A Comparison between Internal and External Malicious Traffic - Michel Cukier; Panjwani,S. (2007)
This paper empirically compares malicious traffic originating inside an organization (i.e., internal traffic) with malicious traffic originating outside an organization (i.e., external traffic). Two honeypot target computers were deployed to collect malicious traffic data over a period of fifteen weeks. In the first study we showed that there was a weak correlation between internal and external traffic based on the number of malicious connections. Since the type of malicious activity is linked to the port that was targeted, we focused on the most frequently targeted ports. We observed that internal malicious traffic often contained different malicious content compared to that of external traffic. In the third study, we discovered that the volume of malicious traffic was linked to the day of the week. We showed that internal and external malicious activities differ: where the external malicious activity is quite stable over the week, the internal traffic varied as a function of the users' activity profile.
Keywords: Computer networks; Data analysis; external traffic; honeypot target computers; internal traffic; malicious traffic data; security of data; user activity profile

Conducting In Situ Evaluations for and With Ubiquitous Computing Technologies - Consolvo,Sunny; Harrison,Beverly; Smith,Ian; Chen,Mike Y.; Everitt,Katherine; Jon Froehlich; Landay,James A. (International Journal of Human-Computer Interaction, 2007)
Abstract To evaluate ubiquitous computing technologies, which may be embedded in the environment, embedded in objects, worn, or carried by the user throughout everyday life, it is essential to use methods that accommodate the often unpredictable, real-world environments in which the technologies are used. This article discusses how we have adapted and applied traditional methods from psychology and human-computer interaction, such as Wizard of Oz and Experience Sampling, to be more amenable to the in situ evaluations of ubiquitous computing applications, particularly in the early stages of design. The way that ubiquitous computing technologies can facilitate the in situ collection of self-report data is also discussed. Although the focus is on ubiquitous computing applications and tools for their assessment, it is believed that the in situ evaluation tools that are proposed will be generally useful for field trials of other technology, applications, or formative studies that are concerned with collecting data in situ.Abstract To evaluate ubiquitous computing technologies, which may be embedded in the environment, embedded in objects, worn, or carried by the user throughout everyday life, it is essential to use methods that accommodate the often unpredictable, real-world environments in which the technologies are used. This article discusses how we have adapted and applied traditional methods from psychology and human-computer interaction, such as Wizard of Oz and Experience Sampling, to be more amenable to the in situ evaluations of ubiquitous computing applications, particularly in the early stages of design. The way that ubiquitous computing technologies can facilitate the in situ collection of self-report data is also discussed. Although the focus is on ubiquitous computing applications and tools for their assessment, it is believed that the in situ evaluation tools that are proposed will be generally useful for field trials of other technology, applications, or formative studies that are concerned with collecting data in situ.

Covering array sampling of input event sequences for automated gui testing - Xun Yuan; Cohen,Myra; Memon, Atif M. (Proceedings of the twenty-second IEEE/ACM international conference on Automated software engineering, 2007)
This paper describes a new automated technique to generate test cases for GUIs by using covering arrays (CAs). The key motivation is to generate long GUI event sequences that are systematically sampled at a particular coverage strength. CAs, to date, have not been effectively used in sampling event driven systems such as GUIs which maintain state. We leverage a "stateless" abstraction of GUIs that allows us to use CAs. Once the CAs have been generated, we reuse the abstractions to reinsert ordering relationships between GUI events, thereby creating executable test cases. A feasibility study on a well-studied GUI-based application shows that the new technique is able to detect a large number of previously undetected faults
Keywords: covering arrays; event driven software; GUI testing

Creating a nationwide wireless detection sensor network for chemical, biological and radiological threats - Rita R Colwell; Peeters,J. (Gentag White Paper, 2007)

Cross-layer latency minimization in wireless networks with SINR constraints - Chafekar,Deepti; Kumar,V. S. Anil; Marathe,Madhav V.; Parthasarathy,Srinivasan; Srinivasan, Aravind (Proceedings of the 8th ACM international symposium on Mobile ad hoc networking and computing, 2007)
Recently, there has been substantial interest in the design of cross-layer protocols for wireless networks. These protocols optimize certain performance metric(s) of interest (e.g. latency, energy, rate) by jointly optimizing the performance of multiple layers of the protocol stack. Algorithm designers often use geometric-graph-theoretic models for radio interference to design such cross-layer protocols. In this paper we study the problem of designing cross-layer protocols for multi-hop wireless networks using a more realistic Signal to Interference plus Noise Ratio (SINR) model for radio interference. The following cross-layer latency minimization problem is studied: Given a set V of transceivers, and a set of source-destination pairs, (i) choose power levels for all the transceivers, (ii) choose routes for all connections, and (iii) construct an end-to-end schedule such that the SINR constraints are satisfied at each time step so as to minimize the make-span of the schedule (the time by which all packets have reached their respective destinations). We present a polynomial-time algorithm with provable worst-case performance guarantee for this cross-layer latency minimization problem. As corollaries of the algorithmic technique we show that a number of variants of the cross-layer latency minimization problem can also be approximated efficiently in polynomial time. Our work extends the results of Kumar et al. (Proc. SODA, 2004) and Moscibroda et al. (Proc. MOBIHOC, 2006). Although our algorithm considers multiple layers of the protocol stack, it can naturally be viewed as compositions of tasks specific to each layer --- this allows us to improve the overall performance while preserving the modularity of the layered structure.
Keywords: cross-layer design; end-to-end scheduling; Interference; SINR model; Wireless networks

Dataflow-based mapping of computer vision algorithms onto FPGAs - Sen,M.; Corretjer,I.; Haim,F.; Saha,S.; Schlessman,J.; Lv,T.; Bhattacharyya, Shuvra S.; Wolf,W. (EURASIP Journal on Embedded Systems, 2007)

Description of Computer Science Higher Education in Sub-Saharan Africa: Initial Explorations - Marshini Chetty; Buckhalter, Celeste; Best, Michael L.; Grinter, Rebecca E.; Guzdial, Mark (2007)
Many countries in Sub-Saharan Africa (SSA) are in need oftechnology innovators who are equipped to leverage technologies in locally relevant domains such as health, government and education. To create skilled graduates who can build and shape locally relevant technologies, higher education institutes in Africa must have Computer Science (CS) education programs that meet local needs, for example, to satisfy the demand for entrepreneurs to build industry and strengthen an economy. This paper characterizes the current state of CS education in SSA in order to identify opportunities for addressing education challenges and to make suggestions that may improve the Information and Communication Technology (ICT) infrastructure in this region. We present the results of a survey of CS educators in SSA institutions of higher education, which was aimed at exploring the issues they face. In addition to the continued chronic under-funding of SSA education, we found that universities in SSA have smaller departments, less focus on Human Computer Interaction (HCI) and offer a variety of courses aside from undergraduate Bachelors degrees. We discuss directions to improve CS curricula through investing in locally tailored courses and changing perceptions of the value of SSA CS higher education programs, standards and educators. Further, we reflect on the challenges of conducting research on SSA. We conclude that further research in this area is needed to build on the ideas we offer here to continue to strengthen CS higher education in SSA.
Keywords: Sub-Saharan Africa; Undergraduate computing education

Discovering interesting usage patterns in text collections: integrating text mining with visualization - Don,Anthony; Zheleva,Elena; Gregory,Machon; Tarkan,Sureyya; Auvil,Loretta; Clement,Tanya; Shneiderman, Ben; Plaisant, Catherine (Proceedings of the sixteenth ACM conference on Conference on information and knowledge management, 2007)
This paper addresses the problem of making text mining results more comprehensible to humanities scholars, journalists, intelligence analysts, and other researchers, in order to support the analysis of text collections. Our system, FeatureLens1, visualizes a text collection at several levels of granularity and enables users to explore interesting text patterns. The current implementation focuses on frequent itemsets of n-grams, as they capture the repetition of exact or similar expressions in the collection. Users can find meaningful co-occurrences of text patterns by visualizing them within and across documents in the collection. This also permits users to identify the temporal evolution of usage such as increasing, decreasing or sudden appearance of text patterns. The interface could be used to explore other text features as well. Initial studies suggest that FeatureLens helped a literary scholar and 8 users generate new hypotheses and interesting insights using 2 text collections.
Keywords: digital humanities; frequent closed itemsets; n-grams; text mining; user interface

Distribution-Free Testing Lower Bounds for Basic Boolean Functions - Dana Dachman-Soled; Servedio, Rocco A. (Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques, 2007)
In the distribution-free property testing model, the distance between functions is measured with respect to an arbitrary and unknown probability distribution \mathcal{D} over the input domain. We consider distribution-free testing of several basic Boolean function classes over {0,1} n , namely monotone conjunctions, general conjunctions, decision lists, and linear threshold functions. We prove that for each of these function classes, Ω((n/logn)1/5) oracle calls are required for any distribution-free testing algorithm. Since each of these function classes is known to be distribution-free properly learnable (and hence testable) using Θ(n) oracle calls, our lower bounds are within a polynomial factor of the best possible.
Keywords: Algorithm Analysis and Problem Complexity; Discrete Mathematics in Computer Science; Numeric Computing

Draft Genome of the Filarial Nematode Parasite Brugia Malayi - Ghedin,Elodie; Wang,Shiliang; Spiro,David; Caler,Elisabet; Zhao,Qi; Crabtree,Jonathan; Allen,Jonathan E; Delcher,Arthur L.; Guiliano,David B; Miranda-Saavedra,Diego; Angiuoli,Samuel V; Creasy,Todd; et al. (Science, 2007)
Parasitic nematodes that cause elephantiasis and river blindness threaten hundreds of millions of people in the developing world. We have sequenced the ∼90 megabase (Mb) genome of the human filarial parasite Brugia malayi and predict ∼11,500 protein coding genes in 71 Mb of robustly assembled sequence. Comparative analysis with the free-living, model nematode Caenorhabditis elegans revealed that, despite these genes having maintained little conservation of local synteny during ∼350 million years of evolution, they largely remain in linkage on chromosomal units. More than 100 conserved operons were identified. Analysis of the predicted proteome provides evidence for adaptations of B. malayi to niches in its human and vector hosts and insights into the molecular basis of a mutualistic relationship with its Wolbachia endosymbiont. These findings offer a foundation for rational drug design.

Efficient Indexing For Articulation Invariant Shape Matching And Retrieval - Biswas,S.; Aggarwal,G.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
Most shape matching methods are either fast but too simplistic to give the desired performance or promising as far as performance is concerned but computationally demanding. In this paper, we present a very simple and efficient approach that not only performs almost as good as many state-of-the-art techniques but also scales up to large databases. In the proposed approach, each shape is indexed based on a variety of simple and easily computable features which are invariant to articulations and rigid transformations. The features characterize pairwise geometric relationships between interest points on the shape, thereby providing robustness to the approach. Shapes are retrieved using an efficient scheme which does not involve costly operations like shape-wise alignment or establishing correspondences. Even for a moderate size database of 1000 shapes, the retrieval process is several times faster than most techniques with similar performance. Extensive experimental results are presented to illustrate the advantages of our approach as compared to the best in the field.
Keywords: alignment; image; articulation; geometric; invariant; matching; image; matching; indexing; invariant; relationships; shape-wise; retrieval; indexing; retrieval; pairwise; SHAPE

An empirical study of filesystem activity following a SSH compromise - Molina,J.; Gordon,J.; Chorin,X.; Michel Cukier (2007)
Monitoring filesystem data is a common method used to detect attacks. Once a computer is compromised, attackers will likely alter files, add new files or delete existing files. The changes that attackers make may target any part of the filesystem, including metadata along with files (e.g., permissions, ownerships and inodes). In this paper, we describe an empirical study that focused on SSH compromised attacks. First statistical data on the number of files targeted and the associated activity (e.g., read, write, delete, ownership and rights) is reported. Then, we refine the analysis to identify and understand patterns in the attack activity.
Keywords: attack activity; filesystem activity; filesystem data monitoring; intrusion detection systems evaluation; meta data; metadata; security of data; SSH compromised attacks

Epitomic Representation of Human Activities - Cuntoor, N.P.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
We introduce an epitomic representation for modeling human activities in video sequences. A video sequence is divided into segments within which the dynamics of objects is assumed to be linear and modeled using linear dynamical systems. The tuple consisting of the estimated system matrix, statistics of the input signal and the initial state value is said to form an epitome. The system matrices are decomposed using the Iwasawa matrix decomposition to isolate the effect of rotation, scaling and projective action on the state vector. "We demonstrate the usefulness of the proposed representation and decomposition for activity recognition using the TSA airport surveillance dataset and the UCF indoor human action dataset.
Keywords: action; activities; airport; dataset; epitomic; dataset; UCF; decomposition; modelling; statistics; video; decomposition; TSA; dynamical; human; indoor; Iwasawa; matrix; matrix; human; modeling; input; processing; representation; estimated; sequences; image; sequences; matrix; signal; statistics; linear; Surveillance; system; systems; video

Estimation of contour motion and deformation for nonrigid object tracking - Jie Shao; Porikli,Fatih; Chellapa, Rama (Journal of the Optical Society of America AJ. Opt. Soc. Am. A, 2007)
We present an algorithm for nonrigid contour tracking in heavily cluttered background scenes. Based on the properties of nonrigid contour movements, a sequential framework for estimating contour motion and deformation is proposed. We solve the nonrigid contour tracking problem by decomposing it into three subproblems: motion estimation, deformation estimation, and shape regulation. First, we employ a particle filter to estimate the global motion parameters of the affine transform between successive frames. Then we generate a probabilistic deformation map to deform the contour. To improve robustness, multiple cues are used for deformation probability estimation. Finally, we use a shape prior model to constrain the deformed contour. This enables us to retrieve the occluded parts of the contours and accurately track them while allowing shape changes specific to the given object types. Our experiments show that the proposed algorithm significantly improves the tracker performance.
Keywords: Motion detection; VISION

Evolution of genes and genomes on the Drosophila phylogeny - Clark,Andrew G.; Eisen,Michael B.; Smith,Douglas R.; Bergman,Casey M.; Oliver,Brian; Markow,Therese A.; Kaufman,Thomas C.; Kellis,Manolis; Gelbart,William; Iyer,Venky N.; Pollard,Daniel A.; Sackton,Timothy B.; et al. (Nature, 2007)
Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.

Evolution of genes and genomes on the Drosophila phylogeny - Clark, A.G.; Eisen,M. B; Smith,D. R; Bergman, C.M.; Oliver, B.; Markow, T.A.; Kaufman, T.C.; Kellis, M.; Gelbart, W.; Iyer, V.N.; others (Nature, 2007)

Face and Gesture Recognition-Appearance Characterization of Linear Lambertian Objects, Generalized Photometric Stereo, and Illumination-Invariant Face Recognition - Zhou,S. K; Aggarwal,G.; Chellapa, Rama; Jacobs, David W. (IEEE Transactions on Pattern Analysis and Machine Intelligence, 2007)

Fast Bilinear SfM with Side Information - Ramachandran, M.; Veeraraghavan,A.; Chellapa, Rama (Computer Vision, 2007. ICCV 2007. IEEE 11th International Conference on, 2007)
We study the beneficial effect of side information on the Structure from Motion (SfM) estimation problem. The side information that we consider is measurement of a 'reference vector' and distance from fixed plane perpendicular to that reference vector. Firstly, we show that in the presence of this information, the SfM equations can be rewritten similar to a bilinear form in its unknowns. Secondly, we describe a fast iterative estimation procedure to recover the structure of both stationary scenes and moving objects that capitalizes on this information. We also provide a refinement procedure in order to tackle incomplete or noisy side information. We characterize the algorithm with respect to its reconstruction accuracy, memory requirements and stability. Finally, we describe two classes of commonly occurring real-world scenarios in which this algorithm will be effective: (a) presence of a dominant ground plane in the scene and (b) presence of an inertial measurement unit on board. Experiments using both real data and rigorous simulations show the efficacy of the algorithm.
Keywords: bilinear; Estimation; estimation; estimation; reference; information; image; methods; motion; procedure; motion; procedure; side; reconstruction; iterative; recovery; image; structure; vector; refinement

Filesystem activity following a SSH compromise: an empirical study of file sequences - Molina,Jesus; Chorin,Xavier; Michel Cukier (Springer-Verlag, 2007)
A common method used to detect intrusions is monitoring filesystem data. Once a computer is compromised, an attacker may alter files, add new files or delete existing ones. Attackers may target any part of the filesystem, including metadata along with files (e.g., permissions, ownerships and inodes). In this paper, we will describe an empirical study that focused on computer attack activity after a SSH compromise. Statistical data will be provided on the number of files targeted and the associated activity (e.g., read, write, delete, ownership and rights). We extend this analysis to include the sequence of files and activities targeted. We focused on the most frequent sequences of consecutive files and activities, then explored in greater detail the longer sequences using state machines. Finally, we developed a simple state machine representing three major observed attack activities (i.e., reconnaissance, malware download and password change) with the number of transitions and time for each transition. The analysis of individual and sequences of files and activities will help to better understand attack activity patterns resulting in more efficient intrusion detection.
Keywords: filesystem data; host intrusion detection systems; intrusion detection systems evaluation; SSH compromises

A forward-secure public-key encryption scheme - Canetti,R.; Halevi,S.; Katz, Jonathan (Journal of Cryptology, 2007)
Cryptographic computations are often carried out on insecure devices for which the threat of key exposure represents a serious concern. Forward security allows one to mitigate the damage caused by exposure of secret keys. In a forward-secure scheme, secret keys are updated at regular periods of time; exposure of the secret key corresponding to a given time period does not enable an adversary to "break" the scheme (in the appropriate sense) for any prior time period. We present the first constructions of (non-interactive) forward-secure public-key encryption schemes. Our main construction achieves security against chosen-plaintext attacks in the standard model, and all parameters of the scheme are poly-logarithmic in the total number of time periods. Some variants and extensions of this scheme are also given. We also introduce the notion of binary tree encryption and construct a binary tree encryption scheme in the standard model. Our construction implies the first hierarchical identity-based encryption scheme in the standard model. (The notion of security we achieve, however, is slightly weaker than that achieved by some previous constructions in the random oracle model.)

From Videos to Verbs: Mining Videos for Activities using a Cascade of Dynamical Systems - Turaga, P.K.; Veeraraghavan,A.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
Clustering video sequences in order to infer and extract activities from a single video stream is an extremely important problem and has significant potential in video indexing, surveillance, activity discovery and event recognition. Clustering a video sequence into activities requires one to simultaneously recognize activity boundaries (activity consistent subsequences) and cluster these activity subsequences. In order to do this, we build a generative model for activities (in video) using a cascade of dynamical systems and show that this model is able to capture and represent a diverse class of activities. We then derive algorithms to learn the model parameters from a video stream and also show how a single video sequence may be clustered into different clusters where each cluster represents an activity. We also propose a novel technique to build affine, view, rate invariance of the activity into the distance metric for clustering. Experiments show that the clusters found by the algorithm correspond to semantically meaningful activities.
Keywords: activities; clustering; image; clustering; video; extraction; dynamical; mining; video; processing; sequence; sequences; pattern; signal; stream; video; systems; single; video

Functional connectivity in fMRI: A modeling approach for estimation and for relating to local circuits - Winder,R.; Cortes,C. R; Reggia, James A.; Tagamets,M. A (Neuroimage, 2007)

GATA and Nkx factors synergistically regulate tissue-specific gene expression and development in vivo - Zhang,Yuzhen; Rath,Nibedita; Hannenhalli, Sridhar; Wang,Zhishan; Cappola,Thomas; Kimura,Shioko; Atochina-Vasserman,Elena; Lu,Min Min; Beers,Michael F.; Morrisey,Edward E. (Development, 2007)
In vitro studies have suggested that members of the GATA and Nkx transcription factor families physically interact, and synergistically activate pulmonary epithelial- and cardiac-gene promoters. However, the relevance of this synergy has not been demonstrated in vivo. We show that Gata6-Titf1 (Gata6-Nkx2.1) double heterozygous (G6-Nkx DH) embryos and mice have severe defects in pulmonary epithelial differentiation and distal airway development, as well as reduced phospholipid production. The defects in G6-Nkx DH embryos and mice are similar to those observed in human neonates with respiratory distress syndromes, including bronchopulmonary dysplasia, and differential gene expression analysis reveals essential developmental pathways requiring synergistic regulation by both Gata6 and Titf1 (Nkx2.1). These studies indicate that Gata6 and Nkx2.1 act in a synergistic manner to direct pulmonary epithelial differentiation and development in vivo, providing direct evidence that interactions between these two transcription factor families are crucial for the development of the tissues in which they are co-expressed.

Gaussian Approximations for Energy-Based Detection and Localization in Sensor Networks - Cevher,Volkan; Chellapa, Rama; McClellan,James H. (Statistical Signal Processing, 2007. SSP '07. IEEE/SP 14th Workshop on, 2007)
Energy-based detection and estimation are crucial in sensor networks for sensor localization, target tracking, etc. In this paper, we present novel Gaussian approximations that are applicable to general energy-based source detection and localization problems in sensor networks. Using our approximations, we derive receiver operating characteristics curves and Cramer-Rao bounds, and we provide a factorized variational Bayes approximation to the location and source energy posterior for centralized or decentralized estimation. When the source signal and the sensor noise have uncorrelated Gaussian distributions, we demonstrate that the envelope of the sensor output can be accurately modeled with a multiplicative Gaussian noise model, which results in smaller estimation biases than the other Gaussian models typically used in the literature. We also prove that additive Gaussian noise models result in negatively biased speed estimates under the same signal assumptions, which can be circumvented by the proposed approximations.

Genome Analysis Linking Recent European and African Influenza (H5N1) Viruses - Salzberg,Steven L.; Kingsford, Carl; Cattoli,Giovanni; Spiro,David J.; Janies,Daniel A.; Aly,Mona Mehrez; Brown,Ian H.; Couacy-Hymann,Emmanuel; De Mia,Gian Mario; Dung,Do Huu; Guercio,Annalisa; Joannis,Tony; et al. (Emerging Infectious DiseasesEmerg Infect Dis, 2007)
Although linked, these viruses are distinct from earlier outbreak strains., To better understand the ecology and epidemiology of the highly pathogenic avian influenza virus in its transcontinental spread, we sequenced and analyzed the complete genomes of 36 recent influenza A (H5N1) viruses collected from birds in Europe, northern Africa, and southeastern Asia. These sequences, among the first complete genomes of influenza (H5N1) viruses outside Asia, clearly depict the lineages now infecting wild and domestic birds in Europe and Africa and show the relationships among these isolates and other strains affecting both birds and humans. The isolates fall into 3 distinct lineages, 1 of which contains all known non-Asian isolates. This new Euro-African lineage, which was the cause of several recent (2006) fatal human infections in Egypt and Iraq, has been introduced at least 3 times into the European-African region and has split into 3 distinct, independently evolving sublineages. One isolate provides evidence that 2 of these sublineages have recently reassorted.

Grid Services Base Library: A high-level, procedural application programming interface for writing Globus-based Grid services - Bazinet,A. L; Myers,D. S; Fuetsch,J.; Cummings, Michael P. (Future Generation Comp Syst, 2007)
The Grid Services Base Library (GSBL) is a procedural application programming interface (API) that abstracts many of the high-level functions performed by Globus Grid services, thus dramatically lowering the barriers to writing Grid services. The library has been extensively tested and used for computational biology research in a Globus Toolkit-based Grid system, in which no fewer than twenty Grid services written with this API are deployed.

Grow and Know: Understanding Record-keeping Needs for Tracking the Development of Young Children - Kientz, Julie A.; Arriaga, Rosa I.; Marshini Chetty; Hayes, Gillian R.; Richardson, Jahmeilah; Patel, Shwetak N.; Abowd, Gregory D. (SIGCHI '07, 2007)
From birth through age five, children undergo rapid development and learn skills that will influence them their entire lives. Regular visits to the pediatrician and detailed record-keeping can ensure that children are progressing and can identify early warning signs of developmental delay or disability. However, new parents are often overwhelmed with new responsibilities, and we believe there is an opportunity for computing technology to assist in this process. In this paper, we present a qualitative study aimed at uncovering some specific needs for record-keeping and analysis for new parents and their network of caregivers. Through interviews and focus groups, we have confirmed assumptions about the rationales parents have and the functions required for using technology for record-keeping. We also identify new themes, potential prototypes, and design guidelines for this domain.
Keywords: children; design requirements; developmental delay; healthcare; qualitative study

Guest Editorial: Special Issue on Human Detection and Recognition - Bhanu, B.; Ratha,N. K; Kumar, V.; Chellapa, Rama; Bigun, J. (Information Forensics and Security, IEEE Transactions on, 2007)
The 12 regular papers and three correspondences in this special issue focus on human detection and recognition. The papers represent gait, face (3-D, 2-D, video), iris, palmprint, cardiac sounds, and vulnerability of biometrics and protection against the spoof attacks.

HCI4D: hci challenges in the global south - Marshini Chetty; Grinter, Rebecca E. (SIGCHI EA '07, 2007)
While researchers have designed user-centered systems for the Global South, fewer have discussed the unique challenges facing HCI projects. In this paper, we describe methodological and practical challenges for HCI research and practice in the Global South.
Keywords: global south; hci; methodologies

Heuristic Search and Information Visualization Methods for School Redistricting - desJardins, Marie; Bulka,Blazej; Carr,Ryan; Jordan,Eric; Rheingans,Penny (AI Magazine, 2007)
We describe an application of AI search and information visualization techniques to the problem of school redistricting, in which students are assigned to home schools within a county or school district. This is a multicriteria optimization problem in which competing objectives, such as school capacity, busing costs, and socioeconomic distribution, must be considered. Because of the complexity of the decision-making problem, tools are needed to help end users generate, evaluate, and compare alternative school assignment plans. A key goal of our research is to aid users in finding multiple qualitatively different redistricting plans that represent different trade-offs in the decision space. We present heuristic search methods that can be used to find a set of qualitatively different plans, and give empirical results of these search methods on population data from the school district of Howard County, Maryland. We show the resulting plans using novel visualization methods that we have developed for summarizing and comparing alternative plans.

HIV risk behaviors among female IDUs in developing and transitional countries - Charles,C.; Des Jarlais Don,P. T; Gerry,S. (BMC Public Health, 2007)

How Smart Homes Learn: The Evolution of the Networked Home and Household - Marshini Chetty; Sung, Ja-Young; Grinter, Rebecca E. (UbiComp 2007: Ubiquitous Computing, 2007)
Despite a growing desire to create smart homes, we know little about how networked technologies interact with a house’s infrastructure. In this paper, we begin to close this gap by presenting findings from a study that examined the relationship between home networking and the house itself—and the work that results for householders as a consequence of this interaction. We discuss four themes that emerged: an ambiguity in understanding the virtual boundaries created by wireless networks, the home network control paradox, a new home network access paradox, and the relationship between increased responsibilities and the possibilities of wireless networking.
Keywords: Computer Communication Networks; computers and society; home networking; Information Systems Applications (incl.Internet); infrastructure; smart home; software engineering; Systems and Data Security; User Interfaces and Human Computer Interaction

Human Identification using Gait and Face - Chellapa, Rama; Roy-Chowdhury, A.K.; Kale, A. (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
In general the visual-hull approach for performing integrated face and gait recognition requires at least two cameras. In this paper we present experimental results for fusion of face and gait for the single camera case. We considered the NIST database which contains outdoor face and gait data for 30 subjects. In the NIST database, subjects walk along an inverted Sigma pattern. In (A. Kale, et al., 2003), we presented a view-invariant gait recognition algorithm for the single camera case along with some experimental evaluations. In this chapter we present the results of our view-invariant gait recognition algorithm in (A. Kale, et al., 2003) on the NIST database. The algorithm is based on the planar approximation of the person which is valid when the person walks far away from the camera. In (S. Zhou et al., 2003), an algorithm for probabilistic recognition of human faces from video was proposed and the results were demonstrated on the NIST database. Details of these methods can be found in the respective papers. We give an outline of the fusion strategy here.
Keywords: algorithm; visual-hull; analysis; image; approach; cameras; face; approximation; probabilistic; database; camera; face; databases; fusion; face; fusion; human; fusion; probability; video; Gait; identification; planar; NIST; processing; visual; recognition; recognition; gait; recognition; view-invariant; signal

Hybrid Detectors for Subpixel Targets - Broadwater, J.; Chellapa, Rama (Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2007)
Subpixel detection is a challenging problem in hyperspectral imagery analysis. Since the target size is smaller than the size of a pixel, detection algorithms must rely solely on spectral information. A number of different algorithms have been developed over the years to accomplish this task, but most detectors have taken either a purely statistical or a physics-based approach to the problem. We present two new hybrid detectors that take advantage of these approaches by modeling the background using both physics and statistics. Results demonstrate improved performance over the well-known AMSD and ACE subpixel algorithms in experiments that include multiple targets, images, and area types - especially when dealing with weak targets in complex backgrounds.
Keywords: ACE subpixel algorithm; AMSD subpixel algorithm; hybrid detectors; hyperspectral imagery analysis; physics; statistics; subpixel target detection; subspace detection; object detection; spectral analysis; statistical analysis; target tracking; Algorithms; Artificial In; Automated; Reproducibility of Results; Sensitivity and Specificity; Signal Processing; Computer-Assisted; Computer-Assisted; Models; Computer-Assisted; Pattern Recognition; Statistical; Image Enhancement; Image Interpretation; Statistical; Numerical Analysis

Hyperstereo algorithms for the perception of terrain drop-offs - Mohananchettiar,Arunkumar; Cevher,Volkan; CuQlock-Knopp,Grayson; Chellapa, Rama; Merritt,John (Proceedings of SPIE, 2007)
The timely detection of terrain drop-offs is critical for safe and efficient off-road mobility, whether with human drivers or with terrain navigation systems that use autonomous machine-vision. In this paper, we propose a joint tracking and detection machine-vision approach for accurate and efficient terrain drop-off detection and localization. We formulate the problem using a hyperstereo camera system and build an elevation map using the range map obtained from a stereo algorithm. A terrain drop-off is then detected with the use of optimal drop-off detection filters applied to the range map. For more robust results, a method based on multi-frame fusion of terrain drop-off evidence is proposed. Also presented is a fast, direct method that does not employ stereo disparity mapping. We compared our algorithm's detection of terrain drop-offs with time-code data from human observers viewing the same video clips in stereoscopic 3D. The algorithm detected terrain drop-offs an average of 9 seconds sooner, or 12m farther, than the human observers. This suggests that passive image-based hyperstereo machine-vision may be useful as an early warning system for off-road mobility.

In Situ Evaluation of Tracking Algorithms Using Time Reversed Chains - Wu,Hao; Sankaranarayanan,A. C; Chellapa, Rama (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
Automatic evaluation of visual tracking algorithms in the absence of ground truth is a very challenging and important problem. In the context of online appearance modeling, there is an additional ambiguity involving the correctness of the appearance model. In this paper, we propose a novel performance evaluation strategy for tracking systems based on particle filter using a time reversed Markov chain. Starting from the latest observation, the time reversed chain is propagated back till the starting time t = 0 of the tracking algorithm. The posterior density of the time reversed chain is also computed. The distance between the posterior density of the time reversed chain (at t = 0) and the prior density used to initialize the tracking algorithm forms the decision statistic for evaluation. It is postulated that when the data is generated true to the underlying models, the decision statistic takes a low value. We empirically demonstrate the performance of the algorithm against various common failure modes in the generic visual tracking problem. Finally, we derive a small frame approximation that allows for very efficient computation of the decision statistic.
Keywords: (numerical; algorithm; Markov; chain; tracking; decision; density; time; detection; particle; Evaluation; evaluation; object; filter; performance; Filtering; Markov; methods); tracking; visual; processes; decision; reversed; servoing; situ; statistics; in; strategy; posterior; systems; visual; theory; object; tracking; tracking; particle

Increasing the breadth: applying sensors, inference and self-report in field studies with the MyExperience tool - Jon Froehlich; Chen,Mike Y.; Consolvo,Sunny; Harrison,Beverly; Landay,James A. (Proceedings of the 1st international workshop on System evaluation for mobile platforms, 2007)
Keywords: In situ evaluation; context-aware systems; experience sampling method (ESM); field studies; Mobile computing; toolkits

Indexing Point Triples Via Triangle Geometry - Cranston,C.B.; Samet, Hanan (Data Engineering, 2007. ICDE 2007. IEEE 23rd International Conference on, 2007)
Database search for images containing icons with specific mutual spatial relationships can be facilitated by an appropriately structured index. For the case of images containing subsets each of which consist of three icons, the one-to-one correspondence between (distinct) point triples and triangles allows the use of such triangle attributes as position, size, orientation, and "shape" in constructing a point-based index, in which each triangle maps to a single point in a resulting hyperdimensional index space. Size (based on the triangle perimeter) can be represented by a single linear dimension. The abstract "shape" of a triangle induces a space that is inherently two-dimensional, and a number of alternative definitions of a basis for this space are examined. Within a plane, orientation reduces to rotation, and (after assignment of a reference direction for the triangle) can be represented by a single, spatially closed dimension. However, assignment of a reference direction for triangles possessing a k-fold rotational symmetry presents a significant challenge. Methods are described for characterizing shape and orientation of triangles, and for mapping these attributes onto a set of linear axes to form a combined index. The shape attribute is independent of size, orientation, and position, and the characterization of shape and orientation is stable with respect to small variations in the indexed triangles.
Keywords: database; databases; dimension; spatial; geometry; database; hyperdimensional; index; index; single; index; triangle; indexing; query; linear; point; k-fold; processing; visual; relationships; structured; rotational; search; indexing; space; image; symmetry; point-based

Jmin-image based color-texture segmentation using watershed and hierarchical clustering - Santos, T.T.; Morimoto, CH; Chellapa, Rama (Proceedings of the 8th International Symposium on Mathematical Morphology, 2007)

Joint Acoustic-Video Fingerprinting of Vehicles, Part I - Cevher, V.; Chellapa, Rama; McClellan, J.H. (Acoustics, Speech and Signal Processing, 2007. ICASSP 2007. IEEE International Conference on, 2007)
We address vehicle classification and measurement problems using acoustic and video sensors. In this paper, we show how to estimate a vehicle's speed, width, and length by jointly estimating its acoustic wave-pattern using a single passive sensor that records the vehicle's drive-by noise. The acoustic wave-pattern is approximated using three envelope shape (ES) components, which approximate the shape of the received signal's power envelope. We incorporate the parameters of the ES components along with the estimates of the vehicle engine RPM and number of cylinders to create a vehicle profile vector that forms an intuitive discriminatory feature space. In the companion paper, we discuss vehicle classification and mensuration based on silhouette extraction and wheel detection, using a video sensor. Vehicle speed estimation and classification results are provided using field data.
Keywords: acoustic; acoustic-video; components; joint; detection; acoustic; estimation; video; fingerprinting; passive; processing; processing; acoustic; sensor; vehicle; sensors; acoustic; sensors; wheel; SHAPE; signal; speed; transducers; video; wave-pattern; envelope

Joint Acoustic-Video Fingerprinting of Vehicles, Part II - Cevher, V.; Guo, F.; Sankaranarayanan,A. C; Chellapa, Rama (Acoustics, Speech and Signal Processing, 2007. ICASSP 2007. IEEE International Conference on, 2007)
In this second paper, we first show how to estimate the wheelbase length of a vehicle using line metrology in video. We then address the vehicle fingerprinting problem using vehicle silhouettes and color invariants. We combine the acoustic metrology and classification results discussed in Part I with the video results to improve estimation performance and robustness. The acoustic video fusion is achieved in a Bayesian framework by assuming conditional independence of the observations of each modality. For the metrology density functions, Laplacian approximations are used for computational efficiency. Experimental results are given using field data
Keywords: acoustic-video; analysis; video; approximations; acoustic; Bayesian; colour; density; efficiency; joint; estimation; Bayes; fingerprinting; metrology; framework; Laplacian; functions; performance; fusion; color; identification; image; invariants; computational; methods; acoustic; metrology; acoustic; processing; processing; fingerprint; signal; video

Kernel fully constrained least squares abundance estimates - Broadwater, J.; Chellapa, Rama; Banerjee, A.; Burlina, P. (Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International, 2007)
A critical step for fitting a linear mixing model to hyperspectral imagery is the estimation of the abundances. The abundances are the percentage of each end member within a given pixel; therefore, they should be non-negative and sum to one. With the advent of kernel based algorithms for hyperspectral imagery, kernel based abundance estimates have become necessary. This paper presents such an algorithm that estimates the abundances in the kernel feature space while maintaining the non-negativity and sum-to-one constraints. The usefulness of the algorithm is shown using the AVIRIS Cuprite, Nevada image.
Keywords: abundance; algorithm; kernel; analysis; AVIRIS; based; constrained; constraint; feature; constraint; spectral; estimates; linear; extraction; geophysical; feature; fully; image; hyperspectral; imagery; kernel; least; mixing; model; nonnegativity; processing; geophysical; processing; multidimensional; processing; spectral; signal; space; kernel; squares; techniques; image; unmixing; sum-to-one

Markerless Monocular Tracking of Articulated Human Motion - Liu,Haiying; Chellapa, Rama (Acoustics, Speech and Signal Processing, 2007. ICASSP 2007. IEEE International Conference on, 2007)
This paper presents a method for tracking general 3D general articulated human motion using a single camera with unknown calibration data. No markers, special clothes, or devices are assumed to be attached to the subject. In addition, both the camera and the subject are allowed to move freely, so that long-term view-independent human motion tracking and recognition are possible. We exploit the fact that the anatomical structure of the human body can be approximated by an articulated blob model. The optical flow under scaled orthographic projection is used to relate the spatial-temporal intensity change of the image sequence to the human motion parameters. These motion parameters are obtained by solving a set of linear equations to achieve global optimization. The correctness and robustness of the proposed method are demonstrated using Tai Chi sequences
Keywords: analysis; image; blob; camera; spatial-temporal; Chi; equations; markerless; flow; scaled; human; intensity; cameras; gait; model; articulated; monocular; MOTION; motion; global; optimization; human; orthographic; projection; single; recognition; image; sequence; linear; sequences; anatomical; sequences; optimisation; structure; articulated; Tai; tracking; optical

Measuring variability in sentence ordering for news summarization - Madnani,Nitin; Passonneau,Rebecca; Ayan,Necip Fazil; Conroy,John M.; Dorr, Bonnie J; Klavans,Judith L.; O'Leary, Dianne P.; Schlesinger,Judith D. (Proceedings of the Eleventh European Workshop on Natural Language Generation, 2007)
The issue of sentence ordering is an important one for natural language tasks such as multi-document summarization, yet there has not been a quantitative exploration of the range of acceptable sentence orderings for short texts. We present results of a sentence reordering experiment with three experimental conditions. Our findings indicate a very high degree of variability in the orderings that the eighteen subjects produce. In addition, the variability of reorderings is significantly greater when the initial ordering seen by subjects is different from the original summary. We conclude that evaluation of sentence ordering should use multiple reference orderings. Our evaluation presents several metrics that might prove useful in assessing against multiple references. We conclude with a deeper set of questions: (a) what sorts of independent assessments of quality of the different reference orderings could be made and (b) whether a large enough test set would obviate the need for such independent means of quality assessment.

Method of three-dimensional object reconstruction from a video sequence using a generic model - Chellapa, Rama; Chowdhury,Amit K. Roy; Srinivasan,Sridhar (2007)
In a novel method of 3D modeling of an object from a video sequence using an SfM algorithm and a generic object model, the generic model is incorporated after the SfM algorithm generates a 3D estimate of the object model purely and directly from the input video sequence. An optimization framework provides for comparison of the local trends of the 3D estimate and the generic model so that the errors in the 3D estimate are corrected. The 3D estimate is obtained by fusing intermediate 3D reconstructions of pairs of frames of the video sequence after computing the uncertainty of the two frame solutions. The quality of the fusion algorithm is tracked using a rate-distortion function. In order to combine the generic model with the 3D estimate, an energy function minimization procedure is applied to the 3D estimate. The optimization is performed using a Metropolis-Hasting sampling strategy.

Microarray analysis of gene expression induced by sexual contact in Schistosoma mansoni - Waisberg,Michael; Lobo,Francisco; Cerqueira,Gustavo; Passos,Liana; Carvalho,Omar; Franco,Gloria; El‐Sayed, Najib M. (BMC Genomics, 2007)
BACKGROUND:The parasitic trematode Schistosoma mansoni is one of the major causative agents of Schistosomiasis, a disease that affects approximately 200 million people, mostly in developing countries. Since much of the pathology is associated with eggs laid by the female worm, understanding the mechanisms involved in oogenesis and sexual maturation is an important step towards the discovery of new targets for effective drug therapy. It is known that the adult female worm only develops fully in the presence of a male worm and that the rates of oviposition and maturation of eggs are significantly increased by mating. In order to study gene transcripts associated with sexual maturation and oviposition, we compared the gene expression profiles of sexually mature and immature parasites using DNA microarrays.RESULTS:For each experiment, three amplified RNA microarray hybridizations and their dye swaps were analyzed. Our results show that 265 transcripts are differentially expressed in adult females and 53 in adult males when mature and immature worms are compared. Of the genes differentially expressed, 55% are expressed at higher levels in paired females while the remaining 45% are more expressed in unpaired ones and 56.6% are expressed at higher levels in paired male worms while the remaining 43.4% are more expressed in immature parasites. Real-time RT-PCR analysis validated the microarray results. Several new maturation associated transcripts were identified. Genes that were up-regulated in single-sex females were mostly related to energy generation (i.e. carbohydrate and protein metabolism, generation of precursor metabolites and energy, cellular catabolism, and organelle organization and biogenesis) while genes that were down-regulated related to RNA metabolism, reactive oxygen species metabolism, electron transport, organelle organization and biogenesis and protein biosynthesis.CONCLUSION:Our results confirm previous observations related to gene expression induced by sexual maturation in female schistosome worms. They also increase the list of S. mansoni maturation associated transcripts considerably, therefore opening new and exciting avenues for the study of the conjugal biology and development of new drugs against schistosomes.

Mixed-state models for nonstationary multiobject activities - Cuntoor,Naresh P.; Chellapa, Rama (EURASIP J. Appl. Signal Process., 2007)
We present a mixed-state space approach for modeling and segmenting human activities. The discrete-valued component of the mixed state represents higher-level behavior while the continuous state models the dynamics within behavioral segments. A basis of behaviors based on generic properties of motion trajectories is chosen to characterize segments of activities. A Viterbi-based algorithm to detect boundaries between segments is described. The usefulness of the proposed approach for temporal segmentation and anomaly detection is illustrated using the TSA airport tarmac surveillance dataset, the bank monitoring dataset, and the UCF database of human actions.

MobCast: Overlay Architecture for Seamless IP Mobility using Scalable Anycast Proxies - Lee,C.P.; Attrey,K.; Caballero,C.; Feamster, Nick; Mihail,M.; Copeland,J.A. (Wireless Communications and Networking Conference, 2007.WCNC 2007. IEEE, 2007)
We propose a routing overlay system, MobCast, for simple and efficient routing to mobile hosts. Mobcast nodes advertise the same address space at each proxy location, and each mobile host is assigned a "universal" IP address from this address space, so packets sent to a mobile host's universal IP address automatically go to the nearest proxy on the overlay. The overlay then delivers the packets to the mobile host. Our architecture enables seamless mobility for both micro and macro mobility. While our initial design is not as mature as Mobile IP, it shows great promise to solve the traditional problems of ingress routing, firewalls, NATs, and rapid mobility with much lower complexity. We present our design as a scalable and deployable alternative to mobile IP. In this paper, we focus on describing the MobCast system architecture. We form our arguments for scalability, handoff-speed, and simplicity, and give our initial results for scalability. We postpone a detailed discussion of MobCast's security model for future work.
Keywords: address space; handoff-speed; IP networks; MobCast; mobile hosts; mobile radio; overlay architecture; proxy location; routing overlay system; scalable anycast proxies; seamless IP mobility; telecommunication network routing; universal IP address

Models for advancing PRAM and other algorithms into parallel programs for a PRAM-On-Chip platform - Vishkin, Uzi; Caragea,George C.; Lee,Bryant (IN HANDBOOK OF PARALLEL COMPUTING: MODELS, ALGORITHMS AND APPLICATIONS, EDITORS, 2007)
A bold vision that guided this work is as follows: (i) a parallel algorithms and programming course could become a standard course in every undergraduate computer science program, and (ii) this course could be coupled with a so-called PRAM-On-Chip architecture — a commodity high-end multi-core computer architecture. In fact, the current paper is a tutorial on how to convert PRAM algorithms intoefficient PRAM-On-Chip programs. Coupled with a text on PRAM algorithms as well as an available PRAM-On-Chip tool-chain, comprising a compiler and a simulator, the paper provides the missing link for upgrading a standard theoretical PRAM algorithms class to a parallel algorithms and programming class. Having demonstrated that such a course could cover similar programming projects and material to what is covered by a typical ﬁrst serial algorithms and programming course, the paper suggests that parallel programming in the emerging multi-core era does not need to be more diﬃcult than serial programming. If true, a powerful answer to the so-called parallel programming open problem is being provided. This open problem is currently the main stumbling block for the industry in getting the upcoming generation of multi-core architectures to improve single task completion time using easy-to-program application programmer interfaces. Known constraints of this open problem, such as backwards compatibility on serial code, are also addressed by the overall approach. More concretely, a widely used methodology for advancing parallel algorithmic thinking into parallel algorithms is revisited, and is extended into a methodology for advancing parallel algorithms to PRAM-On-Chip programs. A performance cost model for the PRAM-On-Chip is also presented. It uses as complexity metrics the length of sequence of round trips to memory (LSRTM) and queuing delay (QD) from memory access queues, in addition to standard PRAM computation costs. Highlighting the importance of LSRTM in determining performance is another contribution of the paper. Finally, some alternatives to PRAM algorithms, which, on one hand, are easier-to-think, but, on the other hand, suppress more architecture details, are also discussed.

Multi-Dimensional Range Query over Encrypted Data - Elaine Shi; Bethencourt, J.; Chan, T.-H.H.; Song, Dawn; Perrig, A. (2007)
We design an encryption scheme called multi-dimensional range query over encrypted data (MRQED), to address the privacy concerns related to the sharing of network audit logs and various other applications. Our scheme allows a network gateway to encrypt summaries of network flows before submitting them to an untrusted repository. When network intrusions are suspected, an authority can release a key to an auditor, allowing the auditor to decrypt flows whose attributes (e.g., source and destination addresses, port numbers, etc.) fall within specific ranges. However, the privacy of all irrelevant flows are still preserved. We formally define the security for MRQED and prove the security of our construction under the decision bilinear Diffie-Hellman and decision linear assumptions in certain bilinear groups. We study the practical performance of our construction in the context of network audit logs. Apart from network audit logs, our scheme also has interesting applications for financial audit logs, medical privacy, untrusted remote storage, etc. In particular, we show that MRQED implies a solution to its dual problem, which enables investors to trade stocks through a broker in a privacy-preserving manner.
Keywords: auditing; cryptography; data privacy; decision bilinear Diffie-Hellman; decision linear assumptions; encrypted data; multi-dimensional range query; network audit logs; network gateway; network intrusions

A Multiple-Hypothesis Approach for Multiobject Visual Tracking - Joo,Seong-Wook; Chellapa, Rama (Image Processing, IEEE Transactions on, 2007)
In multiple-object tracking applications, it is essential to address the problem of associating targets and observation data. For visual tracking of multiple targets which involves objects that split and merge, a target may be associated with multiple measurements and many targets may be associated with a single measurement. The space of such data association is exponential in the number of targets and exhaustive enumeration is impractical. We pose the association problem as a bipartite graph edge covering problem given the targets and the object detection information. We propose an efficient method of maintaining multiple association hypotheses with the highest probabilities over all possible histories of associations. Our approach handles objects entering and exiting the field of view, merging and splitting objects, as well as objects that are detected as fragmented parts. Experimental results are given for tracking multiple players in a soccer game and for tracking people with complex interaction in a surveillance setting. It is shown through quantitative evaluation that our method tracks through varying degrees of interactions among the targets with high success rate.
Keywords: Automated; Reproducibility of Results; Sensitivity and Specificity; Signal Processing; bipartite graph edge covering problem; data association; multiobject visual tracking; multiple measurements; multiple-hypothesis approach; multiple-object tracking; object detection; graph theory; object detection; probability; target tracking; Algorithms; Artificial; Computer-Assisted; Motion; Numerical Analysis; Computer-Assisted; Pattern Recognition; Computer-Assisted; Subtraction Technique

MyExperience: a system for in situ tracing and capturing of user feedback on mobile phones - Jon Froehlich; Chen,Mike Y.; Consolvo,Sunny; Harrison,Beverly; Landay,James A. (Proceedings of the 5th international conference on Mobile systems, applications and services, 2007)
This paper presents MyExperience, a system for capturing both objective and subjective in situ data on mobile computing activities. MyExperience combines the following two techniques: 1) passive logging of device usage, user context, and environmental sensor readings, and 2) active context-triggered user experience sampling to collect in situ, subjective user feedback. MyExperience currently runs on mobile phones and supports logging of more than 140 event types, including: 1) device usage such as communication, application usage, and media capture, 2) user context such as calendar appointments, and 3) environmental sensing such as Bluetooth and GPS. In addition, user experience sampling can be targeted to moments of interest by triggering off sensor readings. We present several case studies of field deployments on people's personal phones to demonstrate how MyExperience can be used effectively to understand how people use and experience mobile technology.
Keywords: context-aware systems; experience sampling method (ESM); field studies; in situ evaluation; Mobile computing; SmartPhones; toolkit; usage logging; user surveys; user-centered design

NETB'07: Proceedings of the 3rd USENIX international workshop on Networking meets databases (USENIX Association, 2007)

New records of phytoplankton for Bangladesh. 3. Volvocales - Khondker,Moniruzzaman; Bhuiyan,Rauf Ahmed; Yeasmin,Jenat; Alam,Munirul; Sack,R. Bradley; Huq,Anwar; Rita R Colwell (Bangladesh Journal of Plant Taxonomy, 2007)
This study presents 21 species of Chlamydomonas, four species of Carteria, two species of each of Nephroselmis, Pyramidomonas and Scherffelia, and Collodictyon triciliatum, Polytoma minus, Tetrachloridium ? allorgei and Tetraselmis cordiformis. These species have been reported from some ponds of Mathbaria of Pirojpur and Bakerganj of Barisal districts in Bangladesh.

New records of phytoplankton for Bangladesh. 4. Chlorococcales - Khondker,Moniruzzaman; Bhuiyan,Rauf Ahmed; Yeasim,Jenat; Alam,Munirul; Sack,R. Bradley; Huq,Anwar; Rita R Colwell (Bangladesh Journal of Plant Taxonomy, 2007)
This study presents three species from each of Schroederia, Monoraphidium and Ankistrodesmus, two species and one variety of Dictyosphaerium, two varieties of Pediastrum, and Tetraedron arthrodesmiforme var. contorta, Chlorotetraedron polymorphum, Myrmecia aquatica, Oocystis tainoensis, Nephrocytium spirale, Kirchneriella irregularis, Coelastrum indicum and Scenedesmus similagineus. These taxa have been reported from some ponds of Mathbaria of Pirojpur and Bakerganj of Barisal Districts in Bangladesh.

Optimizing mpf queries - Corrada Bravo, Hector; Ramakrishnan,Raghu (Proceedings of the 2007 ACM SIGMOD international conference on Management of data - SIGMOD '07, 2007)

Password Changes: Empirical Results - Michel Cukier; Sharma,A. (Computers and Software Engineering, 2007)
This paper focuses on a detailed analysis of oneaspect of password evolution based on empirical data: password changes. Passwords can be divided into weak and strong based on how easy it is to crack them. We present a model of password changes and analyze passwords collected during 21 months from a large network of an average of 770 users. The results include tracking the percentage of users with weak passwords over time and the percentage of users changing between weak and strong passwords. Based on the data analysis, the distribution of users switching between weak and strong passwords was characterized and two parameters of the model were estimated.

Pose-Encoded Spherical Harmonics for Face Recognition and Synthesis Using a Single Image - Yue,Zhanfeng; Zhao,Wenyi; Chellapa, Rama (EURASIP Journal on Advances in Signal Processing, 2007)
Face recognition under varying pose is a challenging problem, especially when illumination variations are also present. In this paper, we propose to address one of the most challenging scenarios in face recognition. That is, to identify a subject from a test image that is acquired under different pose and illumination condition from only one training sample (also known as a gallery image) of this subject in the database. For example, the test image could be semifrontal and illuminated by multiple lighting sources while the corresponding training image is frontal under a single lighting source. Under the assumption of Lambertian reflectance, the spherical harmonics representation has proved to be effective in modeling illumination variations for a fixed pose. In this paper, we extend the spherical harmonics representation to encode pose information. More specifically, we utilize the fact that 2D harmonic basis images at different poses are related by close-form linear transformations, and give a more convenient transformation matrix to be directly used for basis images. An immediate application is that we can easily synthesize a different view of a subject under arbitrary lighting conditions by changing the coefficients of the spherical harmonics representation. A more important result is an efficient face recognition method, based on the orthonormality of the linear transformations, for solving the above-mentioned challenging scenario. Thus, we directly project a nonfrontal view test image onto the space of frontal view harmonic basis images. The impact of some empirical factors due to the projection is embedded in a sparse warping matrix; for most cases, we show that the recognition performance does not deteriorate after warping the test image to the frontal view. Very good recognition results are obtained using this method for both synthetic and challenging real images.

Priority and abstraction in process algebra - Cleaveland, Rance; LÃ¼ttgen,Gerald; Natarajan,V. (Information and Computation, 2007)
More than 15 years ago, Cleaveland and Hennessy proposed an extension of the process algebra CCS in which some actions may take priority over others. The theory was equipped with a behavioral congruence based on strong bisimulation.This article gives a full account of the challenges in, and the solutions employed for, defining a semantic theory of observation congruence for this process algebra. A full-abstraction result is presented whose proof relies on a novel approach based on successive approximations for identifying the largest congruence contained in an intuitive but naÃ¯ve equivalence. Prioritized observation congruence is also characterized equationally for the class of finite processes, while its utility for system verification is demonstrated by an illustrative example.
Keywords: Axiomatization; Bisimulation; Full abstraction; Observation congruence; Priority; Process algebra

Profiling Attacker Behavior Following SSH Compromises - Ramsbrock,D.; Berthier,R.; Michel Cukier (2007)
This practical experience report presents the results of an experiment aimed at building a profile of attacker behavior following a remote compromise. For this experiment, we utilized four Linux honeypot computers running SSH with easily guessable passwords. During the course of our research, we also determined the most commonly attempted usernames and passwords, the average number of attempted logins per day, and the ratio of failed to successful attempts. To build a profile of attacker behavior, we looked for specific actions taken by the attacker and the order in which they occurred. These actions were: checking the configuration, changing the password, downloading a file, installing/running rogue code, and changing the system configuration.
Keywords: Linux; Linux honeypot computers; profiling attacker behavior; remote compromise; rogue code; security of data; SSH compromises; system configuration

Protocols in the use of empirical software engineering artifacts - Basili, Victor R.; Zelkowitz, Marvin V; Sjøberg,D. I.K; Johnson,P.; Cowling,A. J (Empirical Software EngineeringEmpirical Software Engineering, 2007)
If empirical software engineering is to grow as a valid scientific endeavor, the ability to acquire, use, share, and compare data collected from a variety of sources must be encouraged. This is necessary to validate the formal models being developed within computer science. However, within the empirical software engineering community this has not been easily accomplished. This paper analyses experiences from a number of projects, and defines the issues, which include the following: (1) How should data, testbeds, and artifacts be shared? (2) What limits should be placed on who can use them and how? How does one limit potential misuse? (3) What is the appropriate way to credit the organization and individual that spent the effort collecting the data, developing the testbed, and building the artifact? (4) Once shared, who owns the evolved asset? As a solution to these issues, the paper proposes a framework for an empirical software engineering artifact agreement. Such an agreement is intended to address the needs for both creator and user of such artifacts and should foster a market in making available and using such artifacts. If this framework for sharing software engineering artifacts is commonly accepted, it should encourage artifact owners to make the artifacts accessible to others (gaining credit is more likely and misuse is less likely). It may be easier for other researchers to request artifacts since there will be a well-defined protocol for how to deal with relevant matters.

QCS: A system for querying, clustering and summarizing documents - Dunlavy,Daniel M.; O’Leary,Dianne P.; Conroy,John M.; Schlesinger,Judith D. (Information Processing & Management, 2007)
Information retrieval systems consist of many complicated components. Research and development of such systems is often hampered by the difficulty in evaluating how each particular component would behave across multiple systems. We present a novel integrated information retrieval system—the Query, Cluster, Summarize (QCS) system—which is portable, modular, and permits experimentation with different instantiations of each of the constituent text analysis components. Most importantly, the combination of the three types of methods in the QCS design improves retrievals by providing users more focused information organized by topic.We demonstrate the improved performance by a series of experiments using standard test sets from the Document Understanding Conferences (DUC) as measured by the best known automatic metric for summarization system evaluation, ROUGE. Although the DUC data and evaluations were originally designed to test multidocument summarization, we developed a framework to extend it to the task of evaluation for each of the three components: query, clustering, and summarization. Under this framework, we then demonstrate that the QCS system (end-to-end) achieves performance as good as or better than the best summarization engines. Given a query, QCS retrieves relevant documents, separates the retrieved documents into topic clusters, and creates a single summary for each cluster. In the current implementation, Latent Semantic Indexing is used for retrieval, generalized spherical k-means is used for the document clustering, and a method coupling sentence “trimming” and a hidden Markov model, followed by a pivoted QR decomposition, is used to create a single extract summary for each cluster. The user interface is designed to provide access to detailed information in a compact and useful format. Our system demonstrates the feasibility of assembling an effective IR system from existing software libraries, the usefulness of the modularity of the design, and the value of this particular combination of modules.
Keywords: clustering; Information retrieval; latent semantic indexing; Sentence trimming; Summarization; TEXT PROCESSING

Recognizing Faces Across Age Progression - Ramanathan,Narayanan; Chellapa, Rama (Face Biometrics for Personal IdentificationFace Biometrics for Personal Identification, 2007)

Recovery in culture of viable but nonculturable Vibrio parahaemolyticus: regrowth or resuscitation? - Coutard,Fran|[ccedil]|ois; Crassous,Philippe; Droguet,Micka|[euml]|l; Gobin,Eric; Rita R Colwell; Pommepuy,Monique; Hervio-Heath,Dominique (The ISME Journal, 2007)
The objective of this study was to explore the recovery of culturability of viable but nonculturable (VBNC) Vibrio parahaemolyticus after temperature upshift and to determine whether regrowth or resuscitation occurred. A clinical strain of V. parahaemolyticus Vp5 was rendered VBNC by exposure to artificial seawater (ASW) at 4°C. Aliquots of the ASW suspension of cells (0.1, 1 and 10 ml) were subjected to increased temperatures of 20°C and 37°C. Culturability of the cells in the aliquots was monitored for colony formation on a rich medium and changes in morphology were measured by scanning (SEM) and transmission (TEM) electron microscopy. Samples of VBNC cells were fixed and examined by SEM, revealing a heterogeneous population comprising small cells and larger, flattened cells. Forty-eight hours after temperature upshift to 20°C or 37°C, both elongation and division by binary fission of the cells were observed, employing SEM and TEM, but only in the 10-ml aliquots. The results suggest that a portion of VBNC cells is able to undergo cell division. It is concluded that a portion of VBNC cells of V. parahaemolyticus subjected to cold temperatures remain viable. After temperature upshift, regrowth of those cells, rather than resuscitation of all bacteria of the initial inoculum, appears to be responsible for recovery of culturability of VBNC cells of V. parahaemolyticus. Nutrient in filtrates of VBNC cells is hypothesized to allow growth of the temperature-responsive cells, with cell division occurring via binary fission, but also including an atypical, asymmetric cell division.
Keywords: ecophysiology; ecosystems; environmental biotechnology; geomicrobiology; ISME J; microbe interactions; microbial communities; microbial ecology; microbial engineering; microbial epidemiology; microbial genomics; microorganisms

Robust Visual Tracking Using the Time-Reversibility Constraint - Wu,Hao; Chellapa, Rama; Sankaranarayanan,A. C; Zhou,S. K (Computer Vision, 2007. ICCV 2007. IEEE 11th International Conference on, 2007)
Visual tracking is a very important front-end to many vision applications. We present a new framework for robust visual tracking in this paper. Instead of just looking forward in the time domain, we incorporate both forward and backward processing of video frames using a novel time-reversibility constraint. This leads to a new minimization criterion that combines the forward and backward similarity functions and the distances of the state vectors between the forward and backward states of the tracker. The new framework reduces the possibility of the tracker getting stuck in local minima and significantly improves the tracking robustness and accuracy. Our approach is general enough to be incorporated into most of the current tracking algorithms. We illustrate the improvements due to the proposed approach for the popular KLT tracker and a search based tracker. The experimental results show that the improved KLT tracker significantly outperforms the original KLT tracker. The time-reversibility constraint used for tracking can be incorporated to improve the performance of optical flow, mean shift tracking and other algorithms.
Keywords: backward; constraint; video; criterion; state; forward; frame; KLT; processing; processing; video; processing; visual; signal; tracker; minimization; tracking; minimisation; video; vectors; time-reversibility

Schistosoma mansoni genome: Closing in on a final gene set - Haas,Brian J.; Berriman,Matthew; Hirai,Hirohisa; Cerqueira,Gustavo G.; LoVerde,Philip T.; El‐Sayed, Najib M. (Experimental Parasitology, 2007)
The Schistosoma mansoni genome sequencing consortium has recently released the latest versions of the genome assembly as well as an automated preliminary gene structure annotation. The combined datasets constitute a vast resource for researchers to exploit in a variety of post-genomic studies with an emphasis of transcriptomic and proteomic tools. Here we present an innovative method used for combining diverse sources of evidence including ab initio gene predictions, protein and transcript sequence homologies, and cross-genome sequence homologies between S. mansoni and Schistosoma japonicum to define a comprehensive list of protein-coding genes.
Keywords: Annotation; Gene finding; Genome; Schistosoma mansoni

Sentiment analysis: Adjectives and adverbs are better than adjectives alone - Benamara,F.; Cesarano,C.; Picariello, A.; Reforgiato,D.; V.S. Subrahmanian (Proceedings of the International Conference on Weblogs and Social Media (ICWSM), 2007)
Most past work on determining the strength of subjective expres-sions within a sentence or a document use specific parts of speech such as adjectives, verbs and nouns. To date, there is almost no work on the use of adverbs in sentiment analysis, nor has there been any work on the use of adverb-adjective combinations (AACs). We propose an AAC-based sentiment analysis technique that uses a lin- guistic analysis of adverbs of degree. We define a set of general axioms (based on a classification of adverbs of degree into five cat- egories) that all adverb scoring techniques must satisfy. Instead of aggregating scores of both adverbs and adjectives using simple scor- ing functions, we propose an axiomatic treatment of AACs based on the linguistic classification of adverbs. Three specific AAC scor- ing methods that satisfy the axioms are presented. We describe the results of experiments on an annotated set of 200 news articles (an- notated by 10 students) and compare our algorithms with some exist- ing sentiment analysis algorithms. We show that our results lead to higher accuracy based on Pearson correlation with human subjects.

Signal Processing for Biometric Systems [DSP Forum] - Jain, A.K.; Chellapa, Rama; Draper, S.C.; Memon, N.; Phillips,P.J.; Vetro, A. (Signal Processing Magazine, IEEE, 2007)
This IEEE signal processing magazine (SPM) forum discuses signal processing applications, technologies, requirements, and standardization of biometric systems. The forum members bring their expert insights into issues such as biometric security, privacy, and multibiometric and fusion techniques. The invited forum members are Prof. Anil K. Jain of Michigan State University, Prof. Rama Chellappa of the University of Maryland, Dr. Stark C. Draper of theUniversity of Wisconsin in Madison, Prof. Nasir Memon of Polytechnic University, and Dr. P. Jonathon Phillips of the National Institute of Standards and Technology. The moderator of the forum is Dr. Anthony Vetro of Mitsubishi Electric Research Labs, and associate editor of SPM.
Keywords: (access; biometric; control); security; signal; forum; signal; magazine; PROCESSING; processing; security; biometric; standardization; fusion; systems; technique; multibiometric; technique; signal; technology; biometrics

Simulation and Analysis of Human Walking Motion - Nandy, K.; Chellapa, Rama (Acoustics, Speech and Signal Processing, 2007. ICASSP 2007. IEEE International Conference on, 2007)
Simulation and analysis of human walking motion has applications in surveillance and healthcare. In this paper we discuss an approach for modeling human walking motion using a mechanical model in the form of a kinematic chain consisting of rigid links and revolute joints. Our goal is to discriminate different types of walking motions using information such as joint torque and angle sequences extracted from the model. The angle sequences are initially extracted using 3D geometry. From these angle sequences we extract the torque sequences using a recursive Newton Euler inverse dynamics algorithm. Time series models and dynamic time warping of the torque and angle sequences are used to characterize and discriminate different walking patterns. A forward dynamics algorithm is also presented for synthesizing different walking sequences like limping from a normal walking torque sequence
Keywords: 3D; algorithm; revolute; analysis; image; chain; mechanical; DYNAMICS; Euler; extraction; image; geometry; angle; inverse; joints; rigid; links; surveillance; time; method; feature; model; recursive; models; torque; MOTION; motion; kinematic; Newton; patterns; Newton; problems; time; sequences; dynamic; sequences; inverse; sequences; walking; series; series; time; simulation; torque; TIME; walking; warp; warping; healthcare; human

Something that is interesting is interesting then: Using text minig and visualizations to aid interpreting repetition in Gertrude Stein’s The Making of Americans - Clement,T.; Don,A.; Plaisant, Catherine; Auvil,L.; Pape,G.; Goren,V. (Proceedings of the Digital Humanities Conference, 2007)

Story creation from heterogeneous data sources - Fayzullin,M.; V.S. Subrahmanian; Albanese, M.; Cesarano,C.; Picariello, A. (Multimedia Tools and Applications, 2007)
There are numerous applications where there is a need to rapidly infer a story about a given subject from a given set of potentially heterogeneous data sources. In this paper, we formally define a story to be a set of facts about a given subject that satisfies a “story length” constraint. An optimal story is a story that maximizes the value of an objective function measuring the goodness of a story. We present algorithms to extract stories from text and other data sources. We also develop an algorithm to compute an optimal story, as well as three heuristic algorithms to rapidly compute a suboptimal story. We run experiments to show that constructing stories can be efficiently performed and that the stories constructed by these heuristic algorithms are high quality stories. We have built a prototype STORY system based on our model—we briefly describe the prototype as well as one application in this paper.

Super-Resolution of Face Images Using Kernel PCA-Based Prior - Chakrabarti,Ayan; Rajagopalan, AN; Chellapa, Rama (Multimedia, IEEE Transactions on, 2007)
We present a learning-based method to super-resolve face images using a kernel principal component analysis-based prior model. A prior probability is formulated based on the energy lying outside the span of principal components identified in a higher-dimensional feature space. This is used to regularize the reconstruction of the high-resolution image. We demonstrate with experiments that including higher-order correlations results in significant improvements
Keywords: analysis; learning-based; analysis; probability; component; Face; image; method; prior; model; face; principal; probability; recognition; image; reconstruction; image; reconstruction; kernel; resolution; principal; super-resolution; high-resolution

Symmetric Objects are Hardly Ambiguous - Aggarwal,G.; Biswas,S.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
Given any two images taken under different illumination conditions, there always exist a physically realizable object which is consistent with both the images even if the lighting in each scene is constrained to be a known point light source at infinity. In this paper, we show that images are much less ambiguous for the class of bilaterally symmetric Lambertian objects. In fact, the set of such objects can be partitioned into equivalence classes such that it is always possible to distinguish between two objects belonging to different equivalence classes using just one image per object. The conditions required for two objects to belong to the same equivalence class are very restrictive, thereby leading to the conclusion that images of symmetric objects are hardly ambiguous. The observation leads to an illumination-invariant matching algorithm to compare images of bilaterally symmetric Lambertian objects. Experiments on real data are performed to show the implications of the theoretical result even when the symmetry and Lambertian assumptions are not strictly satisfied.
Keywords: algorithm; symmetric; bilaterally; images; image; Lambertian; MATCHING; matching; objects; objects; illumination-invariant; objects; symmetric; symmetric

Target Tracking Using a Joint Acoustic Video System - Cevher, V.; Sankaranarayanan,A. C; McClellan, J.H.; Chellapa, Rama (Multimedia, IEEE Transactions on, 2007)
In this paper, a multitarget tracking system for collocated video and acoustic sensors is presented. We formulate the tracking problem using a particle filter based on a state-space approach. We first discuss the acoustic state-space formulation whose observations use a sliding window of direction-of-arrival estimates. We then present the video state space that tracks a target's position on the image plane based on online adaptive appearance models. For the joint operation of the filter, we combine the state vectors of the individual modalities and also introduce a time-delay variable to handle the acoustic-video data synchronization issue, caused by acoustic propagation delays. A novel particle filter proposal strategy for joint state-space tracking is introduced, which places the random support of the joint filter where the final posterior is likely to lie. By using the Kullback-Leibler divergence measure, it is shown that the joint operation of the filter decreases the worst case divergence of the individual modalities. The resulting joint tracking filter is quite robust against video and acoustic occlusions due to our proposal strategy. Computer simulations are presented with synthetic and field data to demonstrate the filter's performance
Keywords: (numerical; acoustic; adaptive; appearance; approach; synchronization; time-delay; data; delay; acoustic; divergence; acoustic; estimate; joint; estimation; hidden; feature; filter; sliding; Filtering; fusion; multitarget; fusion; synchronisation; target; highways; direction-of-arrival; Kullback-Leibler; methods); sensor; model; particle; processing; processing; automated; propagation; removal; optical; signal; system; multimodal; tracking; acoustic; tracking; direction-of-arrival; tracking; occlusion; online; tracking; particle; tracking; video; variable; visual; video; window; state-space

A theoretical model of children's storytelling using physically-oriented technologies (SPOT) - Guha,M.L.; Druin, Allison; Montemayor,J.; Chipman,G.; Farber,A. (Journal of Educational Multimedia and Hypermedia, 2007)

Ultrastructure of coccoid viable but non‐culturable Vibrio cholerae - Chaiyanan,Saipin; Chaiyanan,Sitthipan; Grim,Christopher; Maugel,Timothy; Huq,Anwar; Rita R Colwell (Environmental Microbiology, 2007)
Morphology of viable but non-culturable Vibrio cholerae was monitored for 2 years by scanning and transmission electron microscopy. Morphological changes included very small coccoid forms, after extended incubation at 4°C and room temperature, and sequential transformation from curved rods to irregular (∼1 μm) rods to ∼0.8 μm coccoid cells and, ultimately, to tiny coccoid forms (0.07–0.4 μm). Irregular rod-shaped and coccoid cells were equally distributed in microcosms during the first 30–60 days of incubation at both temperatures, but only coccoid cells were observed after incubation for 60 days at 4°C. When V. cholerae O1 and O139, maintained for 30–60 days at both temperatures, were heated to 45°C for 60 s, after serial passage through 0.45 μm and 0.1 μm filters, and plating on Luria–Bertania (LB) agar, only cells larger than 1 μm yielded colonies on LB agar. Approximately 0.1% of heat-treated cultures were culturable. Cell division in the smallest coccoid cells was observed, yielding daughter cells of equal size, whereas other coccoid cells revealed bleb-like, cell wall evagination, followed by transfer of nuclear material. Coccoid cells of V. cholerae O1 and O139 incubated at 4°C for more than 1 year remained substrate responsive and antigenic.

Usage-based dhcp lease time optimization - Khadilkar,Manas; Feamster, Nick; Sanders,Matt; Clark,Russ (Proceedings of the 7th ACM SIGCOMM conference on Internet measurement, 2007)
The Dynamic Host Configuration Protocol (DHCP) is used to dynamically allocate address space to hosts on a local area network. Despite its widespread usage, few studies exist on DHCP usage patterns, and even less is known about the importance of setting the lease time (the time that a client retains ownership over some IP address) to an appropriate value. Lease time can greatly affect the tradeoff between address space utilization and the number of both renewal messages and client session expirations. In this paper, using a DHCP trace for 5 weekdays from the Georgia Tech campus network, we present the largest known study of DHCP utilization. We also explore how various strategies for setting lease times can dramatically reduce the number of renewals and expirations without prohibitively increasing address space utilization.
Keywords: dhcp; network management; OPTIMIZATION; usage

Using Stereo Matching for 2-D Face Recognition Across Pose - Castillo,C. D; Jacobs, David W. (Computer Vision and Pattern Recognition, 2007. CVPR '07. IEEE Conference on, 2007)
We propose using stereo matching for 2-D face recognition across pose. We match one 2-D query image to one 2-D gallery image without performing 3-D reconstruction. Then the cost of this matching is used to evaluate the similarity of the two images. We show that this cost is robust to pose variations. To illustrate this idea we built a face recognition system on top of a dynamic programming stereo matching algorithm. The method works well even when the epipolar lines we use do not exactly fit the viewpoints. We have tested our approach on the PIE dataset. In all the experiments, our method demonstrates effective performance compared with other algorithms.
Keywords: 2D; estimation; stereo; Face; gallery; image; image; 2D; image; dynamic; matching; dynamic; matching; pose; processing; programming; face; programming; pose; query; recognition; 2D; recognition; image; variation; stereo

Viable but nonculturable Vibrio cholerae O1 in biofilms in the aquatic environment and their role in cholera transmission - Alam,M.; Sultana,M.; Nair,G. B.; Siddique,A. K.; Hasan,N. A.; Sack,R. B.; Sack,D. A.; Ahmed,K. U.; Sadique,A.; Watanabe,H.; Rita R Colwell (Proceedings of the National Academy of Sciences, 2007)
Vibrio cholerae persists in aquatic environments predominantly in a nonculturable state. In this study coccoid, nonculturable V. cholerae O1 in biofilms maintained for 495 days in Mathbaria, Bangladesh, pond water became culturable upon animal passage. Culturability, biofilm formation, and the wbe, ctxA, and rstR2 genes were monitored by culture, direct fluorescent antibody (DFA), and multiplex PCR. DFA counts were not possible after formation of biofilm. Furthermore, wbe, but not ctxA, were amplifiable, even after incubation for 54 and 68 days at room temperature (≈25°C) and 4°C, respectively, when no growth was detectable. Slower biofilm formation and extended culturability were observed for cultures incubated at 4°C, compared with ≈25°C, suggesting biofilm production to be temperature dependent and linked to loss of culturability. Small colonies appearing after incubation in microcosms for 54 and 68 days at 25°C and 4°C, respectively, were wbe positive and ctxA and rstR2 negative, indicating loss of bacteriophage CTXΦ. The coccoid V. cholerae O1 observed as free cells in microcosms incubated for 495 days could not be cultured, but biofilms in the same microcosms yielded culturable cells. It is concluded that biofilms can act as a reservoir for V. cholerae O1 between epidemics because of its long-term viability in biofilms. In contrast to biofilms produced in Mathbaria pond water, V. cholerae O1 in biofilms present in cholera stools and incubated under identical conditions as the Mathbaria pond water biofilms could not be cultured after 2 months, indicating that those V. cholerae cells freshly discharged into the environment are significantly less robust than cells adapted to environmental conditions.Bangladesh bacteriophage CTXΦ DFA multiplex-PCR ctxA

Video Biometrics - Chellapa, Rama; Aggarwal,G. (Image Analysis and Processing, 2007. ICIAP 2007. 14th International Conference on, 2007)
A strong requirement to come up with secure and user- friendly ways to authenticate and identify people, to safeguard their rights and interests, has probably been the main guiding force behind biometrics research. Though a vast amount of research has been done to recognize humans based on still images, the problem is still far from solved for unconstrained scenarios. This has led to an increased interest in using video for the task of biometric recognition. Not only does video provide more information, but also is more suitable for recognizing humans in general surveillance scenarios. Other than the multitude of still frames, video makes it possible to characterize biometrics based on inherent dynamics like gait which is not possible with still images. In this paper, we describe several recent algorithms to illustrate the usefulness of videos to identify humans. A brief discussion on remaining challenges is also included.
Keywords: (access; analysis; video; biometrics; biometrics; control); face; dynamics; ofbiometric; images; surveillance; inherent; MOTION; processing; recognition; image; recognition; still; scenarios; unconstrained; scenarios; video; signal

Acquisition of Articulated Human Body Models Using Multiple Cameras - Sundaresan,Aravind; Chellapa, Rama (Articulated Motion and Deformable ObjectsArticulated Motion and Deformable Objects, 2006)
Motion capture is an important application in different areas such as biomechanics, computer animation, and human-computer interaction. Current motion capture methods typically use human body models in order to guide pose estimation and tracking. We model the human body as a set of tapered super-quadrics connected in an articulated structure and propose an algorithm to automatically estimate the parameters of the model using video sequences obtained from multiple calibrated cameras. Our method is based on the fact that the human body is constructed of several articulated chains that can be visualised as essentially 1-D segments embedded in 3-D space and connected at specific joint locations. The proposed method first computes a voxel representation from the images and maps the voxels to a high dimensional space in order to extract the 1-D structure. A bottom-up approach is then suggested in order to build a parametric (spline-based) representation of a general articulated body in the high dimensional space followed by a top-down probabilistic approach that registers the segments to the known human body model. We then present an algorithm to estimate the parameters of our model using the segmented and registered voxels.

An Adaptive Threshold Method for Hyperspectral Target Detection - Broadwater, J.; Chellapa, Rama (Acoustics, Speech and Signal Processing, 2006. ICASSP 2006 Proceedings. 2006 IEEE International Conference on, 2006)
In this paper, we present a new approach to automatically determine a detector threshold. This research problem is especially important in hyperspectral target detection as targets are typically very similar to the background. While a number of methods exist to determine the threshold, these methods require either large amounts of data or make simplifying assumptions about the background distribution. We use a method called inverse blind importance sampling which requires few samples and makes no a-priori assumptions about the background statistics. Results show the promise of this algorithm to determine thresholds for fixed false alarm densities in hyperspectral detectors
Keywords: adaptive; blind; detection; detection; inverse; importance; method; background; processing; importance; sampling; geophysical; sampling; object; signal; statistics; hyperspectral; target; threshold

Anonymous multi-attribute encryption with range query and conditional decryption - Bethencourt, J.; Chan, H.; Perrig, A.; Elaine Shi; Song,D. (Carnegie Mellon University, 2006)
We introduce the concept of Anonymous Multi-Attribute Encryption with Range Query and Con-ditional Decryption (AMERQCD). In AMERQCD, a plaintext is encrypted under a point in multi- dimensional space. To a computationally bounded adversary, the ciphertext hides both the plaintext and the point under which it is encrypted. In a range query, a master key owner releases the decryp- tion key for an arbitrary hyper-rectangle in space, thus allowing decryption of ciphertexts previ- ously encrypted under any point within the hyper-rectangle. However, a computationally bounded adversary cannot learn any information on ciphertexts outside the range covered by the decryption key (except the fact that they do not lie within this range). We give an efficient construction based on the Decision Bilinear Diffie-Hellman (D-BDH) and Decision Linear (D-Linear) assumption.

Approximate Data Collection in Sensor Networks using Probabilistic Models - Chu,D.; Deshpande, Amol; Hellerstein,J. M; Wei Hong (Proceedings of the 22nd International Conference on Data Engineering, 2006. ICDE '06, 2006)
Wireless sensor networks are proving to be useful in a variety of settings. A core challenge in these networks is to minimize energy consumption. Prior database research has proposed to achieve this by pushing data-reducing operators like aggregation and selection down into the network. This approach has proven unpopular with early adopters of sensor network technology, who typically want to extract complete "dumps" of the sensor readings, i.e., to run "SELECT *" queries. Unfortunately, because these queries do no data reduction, they consume significant energy in current sensornet query processors. In this paper we attack the "SELECT " problem for sensor networks. We propose a robust approximate technique called Ken that uses replicated dynamic probabilistic models to minimize communication from sensor nodes to the network’s PC base station. In addition to data collection, we show that Ken is well suited to anomaly- and event-detection applications. A key challenge in this work is to intelligently exploit spatial correlations across sensor nodes without imposing undue sensor-to-sensor communication burdens to maintain the models. Using traces from two real-world sensor network deployments, we demonstrate that relatively simple models can provide significant communication (and hence energy) savings without undue sacrifice in result quality or frequency. Choosing optimally among even our simple models is NPhard, but our experiments show that a greedy heuristic performs nearly as well as an exhaustive algorithm.
Keywords: Batteries; Biological system modeling; Biosensors; data mining; Databases; Energy consumption; Intelligent networks; Intelligent sensors; Robustness; Wireless sensor networks

An architecture for adaptive intrusion-tolerant applications - Pal,Partha; Rubel,Paul; Atighetchi,Michael; Webber,Franklin; Sanders,William H.; Seri,Mouna; Ramasamy,HariGovind; Lyons,James; Courtney,Tod; Agbaria,Adnan; Michel Cukier; Gossett,Jeanna; et al. (Software: Practice and Experience, 2006)
Applications that are part of a mission-critical information system need to maintain a usable level of key services through ongoing cyber-attacks. In addition to the well-publicized denial of service (DoS) attacks, these networked and distributed applications are increasingly threatened by sophisticated attacks that attempt to corrupt system components and violate service integrity. While various approaches have been explored to deal with DoS attacks, corruption-inducing attacks remain largely unaddressed. We have developed a collection of mechanisms based on redundancy, Byzantine fault tolerance, and adaptive middleware that help distributed, object-based applications tolerate corruption-inducing attacks. In this paper, we present the ITUA architecture, which integrates these mechanisms in a framework for auto-adaptive intrusion-tolerant systems, and we describe our experience in using the technology to defend a critical application that is part of a larger avionics system as an example. We also motivate the adaptive responses that are key to intrusion tolerance, and explain the use of the ITUA architecture to support them in an architectural framework. Copyright © 2006 John Wiley & Sons, Ltd.
Keywords: adaptive defense; adaptive middleware; Byzantine fault tolerance; intrusion tolerance; redundancy; survivability architecture

Assessing the Attack Threat due to IRC Channels - Meyer,R.; Michel Cukier (2006)
This practical experience report presents the results of an investigation into the threat of attacks associated with the chat medium IRC. A combination of simulated users (i.e., bots), some configured with scripts that simulated conversations, and regular users were used. The average number of attacks per day a user on IRC can expect, the effect of channel activity, gender based on the name, and network type on the number of attacks were determined. The social structure of IRC channels and the types of users that use it were analyzed. The results indicate that attacks through IRC channels come from human users selecting targets rather than automated scripts targeting every user in a channel
Keywords: attack threat assessment; channel activity; client-server systems; computer crime; intrusion-resilient channels; IRC channels; IRC protocols; Protocols; telecommunication channels; telecommunication security

Attribute Grammar-Based Event Recognition and Anomaly Detection - Joo,Seong-Wook; Chellapa, Rama (Computer Vision and Pattern Recognition Workshop, 2006. CVPRW '06. Conference on, 2006)
We propose to use attribute grammars for recognizing normal events and detecting abnormal events in a video. Attribute grammars can describe constraints on features (attributes) in addition to the syntactic structure of the input. Events are recognized using an extension of the Earley parser that handles attributes and concurrent event threads. Abnormal events are detected when the input does not follow syntax of the grammar or the attributes do not satisfy the constraints in the attribute grammar to some degree. We demonstrate the effectiveness of our method for the task of recognizing normal events and detecting anomalies in a parking lot.

Back to Basics: CLASSY 2006 - Conroy,John M.; Schlesinger,Judith D.; O'Leary, Dianne P.; Goldstein,Jade (DUC 06 Conference ProceedingsDUC 06 Conference Proceedings, 2006)
The IDA/CCS summarization system, CLASSY, underwent significant change for this year’sDUC. Two changes made processing simpler and faster: 1) we eliminated the use of a POS (part of speech) tagger for sentence splitting and to assist sentence trimming, and 2) we simplified the scoring of sentences for inclusion in the summary by introducing a new “approximate oracle” score. An additional change introduced a modest amount of extra computation: we ordered sentences in the summary using a new Traveling Salesperson (TSP) formulation. These changes improved ROUGE scores on the DUC 2005 data from last year and gave strong performance in the DUC 2006 competition.

A case study of tangible flags: a collaborative technology to enhance field trips - Chipman,G.; Druin, Allison; Beer,D.; Fails,J. A; Guha,M.L.; Simms,S. (Proceedings of the 2006 conference on Interaction design and children, 2006)

Classification-based spatial error concealment for visual communications - Chen,Meng; Yefeng Zheng; M. Wu (EURASIP J. Appl. Signal Process., 2006)
In an error-prone transmission environment, error concealment is an effective technique to reconstruct the damaged visual content. Due to large variations of image characteristics, different concealment approaches are necessary to accommodate the different nature of the lost image content. In this paper, we address this issue and propose using classification to integrate the state-of-the-art error concealment techniques. The proposed approach takes advantage of multiple concealment algorithms and adaptively selects the suitable algorithm for each damaged image area. With growing awareness that the design of sender and receiver systems should be jointly considered for efficient and reliable multimedia communications, we proposed a set of classification-based block concealment schemes, including receiver-side classification, sender-side attachment, and sender-side embedding. Our experimental results provide extensive performance comparisons and demonstrate that the proposed classification-based error concealment approaches outperform the conventional approaches.

CLASSYArabic and English Multi-Document Summarization - Conroy,John M.; O'Leary, Dianne P.; Schlesinger,Judith D. (Multi-Lingual Summarization Evaluation 2006Multi-Lingual Summarization Evaluation 2006, 2006)

Community-oriented network measurement infrastructure (CONMI) workshop report - claffy,kc; Crovella,Mark; Friedman,Timur; Shannon,Colleen; Spring, Neil (ACM SIGCOMM Computer Communication Review, 2006)

Comprehensive analysis of alternative splicing in rice and comparative analyses with Arabidopsis - Campbell,Matthew A.; Haas,Brian J.; Hamilton,John P.; Mount, Stephen M.; Buell,C. Robin (BMC Genomics, 2006)
Recently, genomic sequencing efforts were finished for Oryza sativa (cultivated rice) and Arabidopsis thaliana (Arabidopsis). Additionally, these two plant species have extensive cDNA and expressed sequence tag (EST) libraries. We employed the Program to Assemble Spliced Alignments (PASA) to identify and analyze alternatively spliced isoforms in both species.

Computer Vision, Statistics in - Chellapa, Rama; Chowdhury,Amit K. Roy (Encyclopedia of Statistical SciencesEncyclopedia of Statistical Sciences, 2006)
Computer Vision (CV) broadly refers to the discipline where extraction of useful 2D and/or 3D information from one or more images is of interest. Useful information could consist of features such as edges, lines, curves and textures, or information about depth, motion, object descriptions, etc. CV problems are usually ill-posed inverse problems. Since the image data is usually obtained from sensors such as video cameras, infrared, radar, etc., the information extraction processes often have to deal with data that is corrupted by noise from the sensors and the environment. Statistics can help in obtaining robust and accurate solutions to these inverse problems by modeling the noise processes. We present here a broad overview of the applications of statistics to different computer vision problems and explain in detail two particular applications, tracking and motion analysis, where statistical approaches have been used very successfully.
Keywords: Computer vision; sampling; Statistics; structure from motion; tracking

Configuration and representation of large-scale dataflow graphs using the dataflow interchange format - Corretjer,I.; Hsu,C.; Bhattacharyya, Shuvra S. (Proceedings of the IEEE Workshop on Signal Processing Systems, Banff, Canada, 2006)

Content-based search techniques for searching CAD databases - Gupta, Satyandra K.; Cardone, Antonio; Deshmukh,A. (CAD Conference, 2006)
The popularity of 3D CAD systems is resulting in large assembly and part databases being createdby product development organizations. Over the last few years several content-based techniques have emerged to search these databases. Ability to perform content-based searches on CAD databases is expected to help the designers and manufacturing engineers in many different ways. Representative examples include part-family formation, redesign suggestion generation, supplier selection, cost estimation, tooling design, machine selection, stock selection, and design reuse. This paper covers the following three topics. First, it presents an overview of different types of part search techniques. Second, it presents an overview of the different aspects of assembly search techniques. Finally, it identifies the open challenges in these areas and outlines future research directions.

Covering arrays for efficient fault characterization in complex configuration spaces - Yilmaz,C.; Cohen,M. B; Porter, Adam (IEEE Transactions on Software Engineering, 2006)

Creativity Support Tools: Report From a U.S. National Science Foundation Sponsored Workshop - Shneiderman, Ben; Fischer,Gerhard; Czerwinski,Mary; Resnick,Mitch; Myers,Brad; Candy,Linda; Edmonds,Ernest; Eisenberg,Mike; Giaccardi,Elisa; Hewett,Tom; Jennings,Pamela; Kules,Bill; et al. (International Journal of Human-Computer Interaction, 2006)
Creativity support tools is a research topic with high risk but potentially very high payoff. The goal is to develop improved software and user interfaces that empower users to be not only more productive but also more innovative. Potential users include software and other engineers, diverse scientists, product and graphic designers, architects, educators, students, and many others. Enhanced interfaces could enable more effective searching of intellectual resources, improved collaboration among teams, and more rapid discovery processes. These advanced interfaces should also provide potent support in hypothesis formation, speedier evaluation of alternatives, improved understanding through visualization, and better dissemination of results. For creative endeavors that require composition of novel artifacts (e.g., computer programs, scientific papers, engineering diagrams, symphonies, artwork), enhanced interfaces could facilitate exploration of alternatives, prevent unproductive choices, and enable easy backtracking. This U.S. National Science Foundation sponsored workshop brought together 25 research leaders and graduate students to share experiences, identify opportunities, and formulate research challenges. Two key outcomes emerged: (a) encouragement to evaluate creativity support tools through multidimensional in-depth longitudinal case studies and (b) formulation of 12 principles for design of creativity support tools.Creativity support tools is a research topic with high risk but potentially very high payoff. The goal is to develop improved software and user interfaces that empower users to be not only more productive but also more innovative. Potential users include software and other engineers, diverse scientists, product and graphic designers, architects, educators, students, and many others. Enhanced interfaces could enable more effective searching of intellectual resources, improved collaboration among teams, and more rapid discovery processes. These advanced interfaces should also provide potent support in hypothesis formation, speedier evaluation of alternatives, improved understanding through visualization, and better dissemination of results. For creative endeavors that require composition of novel artifacts (e.g., computer programs, scientific papers, engineering diagrams, symphonies, artwork), enhanced interfaces could facilitate exploration of alternatives, prevent unproductive choices, and enable easy backtracking. This U.S. National Science Foundation sponsored workshop brought together 25 research leaders and graduate students to share experiences, identify opportunities, and formulate research challenges. Two key outcomes emerged: (a) encouragement to evaluate creativity support tools through multidimensional in-depth longitudinal case studies and (b) formulation of 12 principles for design of creativity support tools.

Cross-Path PDMA-Based Error Protection for Streaming Multiuser Video over Multiple Paths - Su,Guan-Ming; Chen,Meng; M. Wu (Image Processing, 2006 IEEE International Conference on, 2006)
In this paper, we consider aggregating multiple video streams and transmitting the merged stream over multiple error-prone paths. We propose a novel multi-stream error protection scheme based on packet division multiplexing access (PDMA) and cross-path forward error coding. Compared with the traditional time division multiplexing access (TDMA)-based error protection scheme, the proposed scheme outperforms 1.43 1.88 dB for the averaged PSNR of all received streams
Keywords: access; error; codes; forward; coding; multiple; coding; video; correction; correction; multi-access; division; error; error-prone; forward; multiplexing; path; multistream; PDMA; cross-path; Protection; scheme; multiuser; streaming; streaming; packet; systems; video; video

Detection, Isolation, and Identification of Vibrio cholerae from the Environment - Huq,Anwar; Grim,Christopher; Rita R Colwell; Nair,G. Balakrish (Current Protocols in MicrobiologyCurrent Protocols in Microbiology, 2006)
Keywords: culturable; DETECTION; Environment; identification; isolation; nonculturable; viable; Vibrio cholerae

Development of a Large-Scale Integrated Neurocognitive Architecture - Part 2: Design and Architecture - Reggia, James A.; Tagamets,M.; Contreras-Vidal,J.; Jacobs, David W.; Weems,S.; Naqvi,W.; Winder,R.; Chabuk,T.; Jung,J.; Yang,C. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2006)
In Part 1 of this report, we outlined a framework for creating an intelligent agentbased upon modeling the large-scale functionality of the human brain. Building on those results, we begin Part 2 by specifying the behavioral requirements of a large-scale neurocognitive architecture. The core of our long-term approach remains focused on creating a network of neuromorphic regions that provide the mechanisms needed to meet these requirements. However, for the short term of the next few years, it is likely that optimal results will be obtained by using a hybrid design that also includes symbolic methods from AI/cognitive science and control processes from the field of artificial life. We accordingly propose a three-tiered architecture that integrates these different methods, and describe an ongoing computational study of a prototype 'mini-Roboscout' based on this architecture. We also examine the implications of some non-standard computational methods for developing a neurocognitive agent. This examination included computational experiments assessing the effectiveness of genetic programming as a design tool for recurrent neural networks for sequence processing, and experiments measuring the speed-up obtained for adaptive neural networks when they are executed on a graphical processing unit (GPU) rather than a conventional CPU. We conclude that the implementation of a large-scale neurocognitive architecture is feasible, and outline a roadmap for achieving this goal.
Keywords: Technical Report

Development of a Large-Scale Integrated Neurocognitive Architecture Part 1: Conceptual Framework - Reggia, James A.; Tagamets,Malle; Contreras-Vidal,Jose; Weems,Scott; Jacobs, David W.; Winder,Ransom; Chabuk,Timur (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2006)
The idea of creating a general purpose machine intelligence that capturesmany of the features of human cognition goes back at least to the earliest days of artificial intelligence and neural computation. In spite of more than a half-century of research on this issue, there is currently no existing approach to machine intelligence that comes close to providing a powerful, general-purpose human-level intelligence. However, substantial progress made during recent years in neural computation, high performance computing, neuroscience and cognitive science suggests that a renewed effort to produce a general purpose and adaptive machine intelligence is timely, likely to yield qualitatively more powerful approaches to machine intelligence than those currently existing, and certain to lead to substantial progress in cognitive science, AI and neural computation. In this report, we outline a conceptual framework for the long-term development of a large-scale machine intelligence that is based on the modular organization, dynamics and plasticity of the human brain. Some basic design principles are presented along with a review of some of the relevant existing knowledge about the neurobiological basis of cognition. Three intermediate-scale prototypes for parts of a larger system are successfully implemented, providing support for the effectiveness of several of the principles in our framework. We conclude that a human-competitive neuromorphic system for machine intelligence is a viable long- term goal, but that for the short term, substantial integration with more standard symbolic methods as well as substantial research will be needed to make this goal achievable.
Keywords: Technical Report

DOCLIB: a Software Library for Document Processing - Jaeger,Stefan; Zhu,Guangyu; David Doermann; Chen,Kevin; Sampat,Summit (International Conference on Document Recognition and Retrieval XIII, 2006)
Most researchers would agree that research in the field of document processing can benefit tremendously from a common software library through which institutions are able to develop and share research-related software and applications across academic, business, and government domains. However, despite several attempts in the past, the research community still lacks a widely-accepted standard software library for document processing. This paper describes a new library called DOCLIB, which tries to overcome the drawbacks of earlier approaches. Many of DOCLIB’s features are unique either in themselves or in their combination with others, e.g. the factory concept for support of different image types, the juxtaposition of image data and metadata, or the add-on mechanism. We cherish the hope that DOCLIB serves the needs of researchers better than previous approaches and will readily be accepted by a larger group of scientists.

Early Recognition Approaches - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
The earliest approaches concerned recognition within small populations, with the volume of data limited largely by the computational resources available then. As illustrated by Fig. 4.1, many sought to derive a human silhouette from an image and, as common in pattern recognition, and then to derive a description which can be associated with the identity of the subject. This gives a ‘statistical’ approach to automatic gait recognition wherein the image sequence is described as a whole, and neither by a model- nor by a motion-based approach, but one which describes the motion content. Given that techniques to separate a moving object from its background have been developed for many years (especially in surveillance) there existed a selection of approaches to derive the silhouette of the moving subject, an example silhouette extraction from the image of Fig. 4.1(a) is shown in Fig. 4.1(b). What was then needed was approaches to process the sequence of silhouettes so as to derive a gait signature — a set of numbers to represent a subject’s identity. A selection of signatures is shown in Fig. 4.1(c) which are displayed in a 3-dimensional space for visualization purposes only (the signature usually has more dimensions than this). These signatures represent ten of walking subjects with four instances of each subject. In this case the signatures derived from the four instances mostly cluster well, representing a good recognition rate. Accordingly, the target of the early approaches was to process video data of the form of Fig. 4.1(a) to obtain silhouettes of the form of Fig. 4.1(b) so as to derive signatures for recognition performance analysis.

Edge Suppression by Gradient Field Transformation Using Cross-Projection Tensors - Agrawal,A.; Raskar, R.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2006 IEEE Computer Society Conference on, 2006)
We propose a new technique for edge-suppressing operations on images. We introduce cross projection tensors to achieve affine transformations of gradient fields. We use these tensors, for example, to remove edges in one image based on the edge-information in a second image. Traditionally, edge suppression is achieved by setting image gradients to zero based on thresholds. A common application is in the Retinex problem, where the illumination map is recovered by suppressing the reflectance edges, assuming it is slowly varying. We present a class of problems where edge-suppression can be a useful tool. These problems involve analyzing images of the same scene under variable illumination. Instead of resetting gradients, the key idea in our approach is to derive local tensors using one image and to transform the gradient field of another image using them. Reconstructed image from the modified gradient field shows suppressed edges or textures at the corresponding locations. All operations are local and our approach does not require any global analysis. We demonstrate the algorithm in the context of several applications such as (a) recovering the foreground layer under varying illumination, (b) estimating intrinsic images in non-Lambertian scenes, (c) removing shadows from color images and obtaining the illumination map, and (d) removing glass reflections.

Effect of transport at ambient temperature on detection and isolation of Vibrio cholerae from environmental samples - Alam,M.; Sadique,A.; Bhuiyan,N. A.; Nair,G. B.; Siddique,A. K.; Sack,D. A.; Ahsan,S.; Huq,A.; Sack,R. B.; Rita R Colwell; others (Applied and environmental microbiology, 2006)
It has long been assumed that prolonged holding of environmental samples at the ambient air temperature prior to bacteriological analysis is detrimental to isolation and detection of Vibrio cholerae, the causative agent of pandemic cholera. The present study was aimed at understanding the effect of transporting environmental samples at the ambient air temperature on isolation and enumeration of V. cholerae. For water and plankton samples held at ambient temperatures ranging from 31°C to 35°C for 20 h, the total counts did not increase significantly but the number of culturable V. cholerae increased significantly compared to samples processed within 1 h of collection, as measured by culture, acridine orange direct count, direct fluorescent-antibody-direct viable count (DFA-DVC), and multiplex PCR analyses. For total coliform counts, total bacterial counts, and DFA-DVC counts, the numbers did not increase significantly, but the culturable plate counts for V. cholerae increased significantly after samples were held at the ambient temperature during transport to the laboratory for analysis. An increase in the recovery of V. cholerae O1 and improved detection of V. cholerae O1 rfb and ctxA also occurred when samples were enriched after they were kept for 20 h at the ambient temperature during transport. Improved detection and isolation of toxigenic V. cholerae from freshwater ecosystems can be achieved by holding samples at the ambient temperature, an observation that has significant implications for tracking this pathogen in diverse aquatic environments.

Efficient position-independent iconic search using an R-theta index - Cranston,Charles B.; Samet, Hanan (Proceedings of the 14th annual ACM international symposium on Advances in geographic information systems, 2006)
An iconic image database is a collection of symbolic images where each image is a collection of labeled point features called icons. A method is presented to support fast position-independent similarity search in an iconic database for symbolic images where the similarity condition involves finding icon pairs that satisfy a specific spatial relationship. This is achieved by introducing an index data structure based on r-θ space, which corresponds to the Cartesian product of separation (i.e., inter-icon distance) and (some representation of) relative spatial orientation. In this space, each pairing of two icons is represented by a single point, and all pairs with the same separation and relative orientation (regardless of absolute position) map to the same point. Similarly, all icon pairs with the same separation but different relative orientations map to points on a line parallel to the θ axis, while all pairs with different separations but the same relative orientation map to points on a line parallel to the r axis. Using such an index, database search for icon pairs with a given spatial relationship or range is accomplished by examining the subarea of the index space into which desired pairs would map. This r-θ index space can be organized using well-known spatial database techniques, such as quadtrees or R-trees. Although the size of such an index grows only linearly with respect to the number of images in the collection, it grows quadratically with the average number of icons in an image. A scheme is described to reduce the size of the index by pruning away a subset of the pairs, at the cost of incurring additional work when searching the database. This pruning is governed by a parameter φ, whose variation provides a continuous range of trade-offs between index size and search time.
Keywords: iconic database; position-independent; spatial indexing

Enhancing reinforcement learning with metacognitive monitoring and control for improved perturbation tolerance - Anderson,M. L; Oates,T.; Chong,W.; Perlis, Don (Journal of Experimental and Theoretical Artificial Intelligence, 2006)

Entity Resolution in Graphs - Bhattacharya,Indrajit; Getoor, Lise (Mining Graph DataMining Graph Data, 2006)
This chapter contains sections titled:Introduction Related Work Motivating Example for Graph-Based Entity Resolution Graph-Based Entity Resolution: Problem Formulation Similarity Measures for Entity Resolution Graph-Based Clustering for Entity Resolution Experimental Evaluation Conclusion References
Keywords: entity resolution in graphs; graph‐based clustering for entity resolution; graph‐based entity resolution problem

Evaluation of Multilingual and Multi-modal Information Retrieval-Seventh Workshop of the Cross-Language Evaluation Forum, CLEF 2006, Alicante, Spain, September 19-21, 2006, Revised Selected Papers - Peters,C.; Clough,P.; Gey,F.; Karlgren,J.; Magnini,B.; Oard, Douglas; De Rijke,M.; Stempfhuber,M. (Seventh Workshop of the Cross-Language Evaluation Forum, CLEF 2006, 2006)

Evolution of non-LTR retrotransposons in the trypanosomatid genomes: Leishmania major has lost the active elements - Bringaud,Frédéric; Ghedin,Elodie; Blandin,Gaëlle; Bartholomeu,Daniella C.; Caler,Elisabet; Levin,Mariano J.; Baltz,Théo; El‐Sayed, Najib M. (Molecular and Biochemical Parasitology, 2006)
The ingi and L1Tc non-LTR retrotransposons - which constitute the ingi clade - are abundant in the genome of the trypanosomatid species Trypanosoma brucei and Trypanosoma cruzi, respectively. The corresponding retroelements, however, are not present in the genome of a closely related trypanosomatid, Leishmania major. To study the evolution of non-LTR retrotransposons in trypanosomatids, we have analyzed all ingi/L1Tc elements and highly degenerate ingi/L1Tc-related sequences identified in the recently completed T. brucei, T. cruzi and L. major genomes. The coding sequences of 242 degenerate ingi/L1Tc-related elements (DIREs) in all three genomes were reconstituted by removing the numerous frame shifts. Three independent phylogenetic analyses conducted on the conserved domains encoded by these elements show that all DIREs, including the 52 L. major DIREs, form a monophyletic group belonging to the ingi clade. This indicates that the trypanosomatid ancestor contained active mobile elements that have been retained in the Trypanosoma species, but were lost from L. major genome, where only remnants (DIRE) are detectable. All 242 DIREs analyzed group together according to their species origin with the exception of 11 T. cruzi DIREs which are close to the T. brucei ingi/DIRE families. Considering the absence of known horizontal transfer between the African T. brucei and the South-American T. cruzi, this suggests that this group of elements evolved at a lower rate when compared to the other trypanosomatid elements. Interestingly, the only nucleotide sequence conserved between ingi and L1Tc (the first 79 residues) is also present at the 5'-extremity of all the full length DIREs and suggests a possible role for this conserved motif, as well as for DIREs.
Keywords: Degenerate retroelement; Evolution; Ingi; L1Tc; Leishmania major; Non-LTR retrotransposon; Retroposon; Trypanosoma brucei; Trypanosoma cruzi

Experiments to understand HPC time to development - Hochstein, Lorin; Nakamura,Taiga; Basili, Victor R.; Asgari, Sima; Zelkowitz, Marvin V; Hollingsworth, Jeffrey K; Shull, Forrest; Carver,Jeffrey; Voelp,Martin; Zazworka, Nico; Johnson,Philip (CTWatch Quarterly, 2006)
In order to understand how high performance computing (HPC) programs are developed, a series of experiments, using students in graduate level HPC classes, have been conducted at many universities in the US. In this paper we discuss the general process of conducting those experiments, give some of the early results of those experiments, and describe a web-based process we are developing that will allow us to run additional experiments at other universities and laboratories that will be easier to conduct and generate results that more accurately reflect the process of building HPC programs.
Keywords: hackystat; HPC; publications-journals

Exploiting independence for branch operations in Bayesian learning of C&RTs - Angelopoulos,N.; Cussens,J.; De Raedt,L.; Dietterich,T.; Getoor, Lise; Muggleton,S. H (Probabilistic, Logical and Relational Learning-Towards a Synthesis, 2006)
In this paper we extend a methodology for Bayesian learning via MCMC, with the ability to grow arbitrarily long branches in C&RT models. We are able to do so by exploiting independence in the model construction process. The ability to grow branches rather than single nodes has been noted as desirable in the literature. The most singular feature of the underline methodology used here in comparison to other approaches is the coupling of the prior and the proposal. The main contribution of this paper is to show how taking advantage of independence in the coupled process, can allow branch growing and swapping for proposal models.

Exploring erotics in Emily Dickinson's correspondence with text mining and visual interfaces - Plaisant, Catherine; Rose,James; Yu,Bei; Auvil,Loretta; Kirschenbaum,Matthew G.; Smith,Martha Nell; Clement,Tanya; Lord,Greg (Proceedings of the 6th ACM/IEEE-CS joint conference on Digital libraries, 2006)
This paper describes a system to support humanities scholars in their interpretation of literary work. It presents a user interface and web architecture that integrates text mining, a graphical user interface and visualization, while attempting to remain easy to use by non specialists. Users can interactively read and rate documents found in a digital libraries collection, prepare training sets, review results of classification algorithms and explore possible indicators and explanations. Initial evaluation steps suggest that there is a rationale for "provocational" text mining in literary interpretation.
Keywords: case studies; humanities; literary criticism; text mining; user interface; Visualization

Face Processing: Advanced Modeling and Methods - Chellapa, Rama; Zhao, W. (Academic Press/Elsevier, 2006)

Face Verification Across Age Progression - Ramanathan,N.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2006)
Human faces undergo considerable amounts of variations with aging. While face recognition systems have been proven to be sensitive to factors such as illumination and pose, their sensitivity to facial aging effects is yet to be studied. How does age progression affect the similarity between a pair of face images of an individual? What is the confidence associated with establishing the identity between a pair of age separated face images? In this paper, we develop a Bayesian age difference classifier that classifies face images of individuals based on age differences and performs face verification across age progression. Further, we study the similarity of faces across age progression. Since age separated face images invariably differ in illumination and pose, we propose preprocessing methods for minimizing such variations. Experimental results using a database comprising of pairs of face images that were retrieved from the passports of 465 individuals are presented. The verification system for faces separated by as many as nine years, attains an equal error rate of 8.5%
Keywords: age; Aging; Bayesian; classification; classification; face; classifier; age; difference; effects; preprocessing; Face; image; images; error; methods; Bayes; methods; error; progression; age; rate; face; recognition; recognition; image; separated; statistics; face; systems; face; verification; facial

Finding Gait in Space and Time - Yang Ran; Chellapa, Rama; Qinfen Zheng (Pattern Recognition, 2006. ICPR 2006. 18th International Conference on, 2006)
We describe an approach to characterize the signatures generated by walking humans in spatio-temporal domain. To describe the computational model for this periodic pattern, we take the mathematical theory of geometry group theory, which is widely used in crystallographic structure research. Both empirical and theoretical analyses prove that spatio-temporal helical patterns generated by legs belong to the Frieze Groups because they can be characterized by a repetitive motif along the direction of walking. The theory is applied to an automatic detection-and-tracking system capable of counting heads and handling occlusion by recognizing such patterns. Experimental results for videos acquired from both static and moving ground sensors are presented. Our algorithm demonstrates robustness to non-rigid human deformation as well as background clutter
Keywords: analysis; analysis; geometry; analysis; group; characterization; occlusion; counting; mathematical; detection-and-tracking; domain; spatiotemporal; Frieze; group; groups; automatic; handling; pattern; helical; humans; computer; MOTION; pattern; spatiotemporal; patterns; walking; recognition; periodic; signature; system; computer; theory; head; theory; image; theory; motion; vision; gait

Flow algorithms for two pipelined filter ordering problems - Condon,Anne; Deshpande, Amol; Hellerstein,Lisa; Wu,Ning (Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems, 2006)
Pipelined filter ordering is a central problem in database query optimization, and has received renewed attention recently in the context of environments such as the web, continuous high-speed data streams and sensor networks. We present algorithms for two natural extensions of the classical pipelined filter ordering problem: (1) a distributional type problem where the filters run in parallel and the goal is to maximize throughput, and (2) an adversarial type problem where the goal is to minimize the expected value of multiplicative regret. We show that both problems can be solved using similar flow algorithms, which find an optimal ordering scheme in time O(n2), where n is the number of filters. Our algorithm for (1) improves on an earlier O(n3 log n) algorithm of Kodialam.
Keywords: flow algorithms; Pipelined filter ordering; Query optimization; selection ordering

From sample similarity to ensemble similarity: probabilistic distance measures in reproducing kernel Hilbert space - Zhou,S. K; Chellapa, Rama (Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2006)
This paper addresses the problem of characterizing ensemble similarity from sample similarity in a principled manner. Using a reproducing kernel as a characterization of sample similarity, we suggest a probabilistic distance measure in the reproducing kernel Hilbert space (RKHS) as the ensemble similarity. Assuming normality in the RKHS, we derive analytic expressions for probabilistic distance measures that are commonly used in many applications, such as Chernoff distance (or the Bhattacharyya distance as its special case), Kullback-Leibler divergence, etc. Since the reproducing kernel implicitly embeds a nonlinear mapping, our approach presents a new way to study these distances whose feasibility and efficiency is demonstrated using experiments with synthetic and real examples. Further, we extend the ensemble similarity to the reproducing kernel for ensemble and study the ensemble similarity for more general data representations.
Keywords: Automated; Sample Size; Signal Processing; Bhattacharyya distance; Chernoff distance; Gram matrix; Kullback-Leibler divergence; data representations; ensemble similarity characterization; nonlinear mapping; probabilistic distance measures; reproducing kernel Hilbert space; sample similarity characterizatio; Computer-Assisted; Statistical; Pattern Recognition

The Function Space of an Activity - Veeraraghavan,A.; Chellapa, Rama; Roy-Chowdhury, A.K. (Computer Vision and Pattern Recognition, 2006 IEEE Computer Society Conference on, 2006)
An activity consists of an actor performing a series of actions in a pre-defined temporal order. An action is an individual atomic unit of an activity. Different instances of the same activity may consist of varying relative speeds at which the various actions are executed, in addition to other intra- and inter- person variabilities. Most existing algorithms for activity recognition are not very robust to intra- and inter-personal changes of the same activity, and are extremely sensitive to warping of the temporal axis due to variations in speed profile. In this paper, we provide a systematic approach to learn the nature of such time warps while simultaneously allowing for the variations in descriptors for actions. For each activity we learn an #145;average #146; sequence that we denote as the nominal activity trajectory. We also learn a function space of time warpings for each activity separately. The model can be used to learn individualspecific warping patterns so that it may also be used for activity based person identification. The proposed model leads us to algorithms for learning a model for each activity, clustering activity sequences and activity recognition that are robust to temporal, intra- and inter-person variations. We provide experimental results using two datasets.

Functional Analysis of Hes-1 in Preadipocytes - Ross,David A; Hannenhalli, Sridhar; Tobias,John W; Cooch,Neil; Shiekhattar,Ramin; Kadesch,Tom (Molecular EndocrinologyMolecular Endocrinology, 2006)
Notch signaling blocks differentiation of 3T3-L1 preadipocytes, and this can be mimicked by constitutive expression of the Notch target gene Hes-1. Although considered initially to function only as a repressor, recent evidence indicates that Hes-1 can also activate transcription. We show here that the domains of Hes-1 needed to block adipogenesis coincide with those necessary for transcriptional repression. HRT1, another basic-helix-loop-helix protein and potential Hes-1 partner, was also induced by Notch in 3T3-L1 cells but did not block adipogenesis, suggesting that Hes-1 functions primarily as a homodimer or possibly as a heterodimer with an unknown partner. Purification of Hes-1 identified the Groucho/transducin-like enhancer of split family of corepressors as the only significant Hes-1 interacting proteins in vivo. An evaluation of global gene expression in preadipocytes identified approximately 200 Hes-1-responsive genes comprising roughly equal numbers of up-regulated and down-regulated genes. However, promoter analyses indicated that the down-regulated genes were significantly more likely to contain Hes-1 binding sites, indicating that Hes-1 is more likely to repress transcription of its direct targets. We conclude that Notch most likely blocks adipogenesis through the induction of Hes-1 homodimers, which repress transcription of key target genes.

Further Gait Developments - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
Human gait characteristics are best analyzed when presented in its canonical view (side view). The dynamics behind an individual’s gait, the quasi-periodicity of an individual’s gait etc. which contribute significantly towards establishing his/her identity are more evident when the canonical view of human gait is presented. Thus, the availability of such a canonical view is crucial to the success of many gait recognition systems. We observe that in surveillance applications a non-canonical view of an individual’s gait is captured more often and this necessitates developing gait recognition algorithms that are view invariant. When individuals walk at an angle oblique to the camera, the performance of gait recognition systems suffers due to the gradual change in the individual’s height and stride length as captured by the camera.

Future Challenges - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
Although a large number of gait recognition algorithms have been reported, it should be noted that gait recognition is still in its infancy. This is because previous work was mainly implemented under some simplified and controlled conditions, e.g., no occlusion during human walking, relatively plain background, the lack of view generality except [142, 103, 102], etc (see Table 8.1). Although reporting good recognition performance, most existing algorithms were usually evaluated on a small and non-realistic database. Further, recognition rates have not yet far reached a possible upper bound even under the above two conditions.

Gait Databases - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
Naturally, the success and evolution of a new application relies largely on the dataset used for evaluation. The early gait databases were collected about 10 years before the time of writing. Then, computers had little power and memory costs were comparatively high. Clearly, this was before digital video and acquisition was based on analogue camcorder technology which resulted in frames being digitized individually. Since techniques were in their infancy, as in face recognition, early databases only had few subjects. The idea then was to determine whether recognition could be achieved at all — or not. At that stage we were not interested in the ramifications of recognition. There were two early databases which were developed independently: the UCSD data was recorded outdoors and the Southampton data was indoors, with subjects wearing special trousers. The current databases are considerably more advanced, but certainly benefited in their development for the early approaches.

The Goal Question Metric Approach - Basili, Victor R.; Caldiera,G.; Rombach,H. D (5th ACM-IEEE International Symposium on Empirical Software Engineering (ISESE’06), 2006)

Heuristic search and information visualization methods for school redistricting - desJardins, Marie; Bulka,Blazej; Carr,Ryan; Hunt,Andrew; Rathod,Priyang; Rheingans,Penny (Proceedings of the 18th conference on Innovative applications of artificial intelligence - Volume 2, 2006)
We describe an application of AI search and information visualization techniques to the problem of school redistricting, in which students are assigned to home schools within a county or school district. This is a multicriteria optimization problem in which competing objectives must be considered, such as school capacity, busing costs, and socioeconomic distribution. Because of the complexity of the decision-making problem, tools are needed to help end users generate, evaluate, and compare alternative school assignment plans. A key goal of our research is to aid users in finding multiple qualitatively different redistricting plans that represent different tradeoffs in the decision space.We present heuristic search methods that can be used to find a set of qualitatively different plans, and give empirical results of these search methods on population data from the school district of Howard County, Maryland. We show the resulting plans using novel visualization methods that we have developed for summarizing and comparing alternative plans.

High-confidence medical device software and systems - Lee,I.; Pappas,G. J; Cleaveland, Rance; Hatcliff,J.; Krogh,B. H; Lee,P.; Rubin,H.; Sha,L. (Computer, 2006)
Given the shortage of caregivers and the increase in an aging US population, the future of US healthcare quality does not look promising and definitely is unlikely to be cheaper. Advances in health information systems and healthcare technology offer a tremendous opportunity for improving the quality of care while reducing costs. The development and production of medical device software and systems is a crucial issue, both for the US economy and for ensuring safe advances in healthcare delivery. As devices become increasingly smaller in physical terms but larger in software terms, the design, testing, and eventual Food and Drug Administration (FDA) device approval is becoming much more expensive for medical device manufacturers both in terms of time and cost. Furthermore, the number of devices that have recently been recalled due to software and hardware problems is increasing at an alarming rate. As medical devices are becoming increasingly networked, ensuring even the same level of health safety seems a challenge.
Keywords: Aging; biomedical equipment; Clinical software engineering; Costs; FDA device; Food and Drug Administration device; health and safety; health care; health information system; health safety; healthcare delivery; Healthcare technology; Information systems; medical computing; medical device manufacturing; medical device software development; medical device systems development; medical information systems; Medical services; Medical software; Medical tests; networked medical devices; Production systems; Software design; Software safety; Software systems; Software testing; US healthcare quality

Human identification based on gait - Nixon,Mark S.; Tan,Tieniu; Chellapa, Rama (Springer Science & Business, 2006)
Biometrics now affect many people's lives, and is the focus of much academic research and commercial development. Gait is one of the most recent biometrics, with its own unique advantages. Gait recognizes people by the way they walk and run, analyzes movement, which in turn implies analyzing sequences of images. This professional book introduces developments from the laboratories of very distinguished researchers within this relatively new area of biometrics and clearly establishes human gait as a biometric. Human Identification Based on Gait provides a snapshot of all the biometric work in human identification by gait (all major centers for research are indicated in this book). To complete the picture, studies are included from medicine, psychology and other areas wherein we find not only justification for the use of gait as a biometric, but also pointers to techniques and to analysis. Human Identification Based on Gait is designed for a professional audience, composed of researchers and practitioners in industry. This book is also suitable as a secondary text for graduate-level students in computer science.
Keywords: Biometric identification; Computers / Computer Graphics; Computers / Computer Science; Computers / Computer Vision & Pattern Recognition; Computers / General; Computers / Information Technology; Computers / Programming / Software Development; Computers / Software Development & Engineering / Systems Analysis & Design; Gait in humans; Medical / Physiology; Social Science / Anthropology / Physical

Image Registration and Fusion Studies for the Integration of Multiple Remote Sensing Data - Le Moigne,J.; Cole-Rhodes,A.; Eastman,R.; Jain,P.; Joshua,A.; Memarsadeghi,N.; Mount, Dave; Netanyahu,N.; Morisette,J.; Uko-Ozoro,E. (Acoustics, Speech and Signal Processing, 2006. ICASSP 2006 Proceedings. 2006 IEEE International Conference on, 2006)
The future of remote sensing will see the development of spacecraft formations, and with this development will come a number of complex challenges such as maintaining precise relative position and specified attitudes. At the same time, there will be increasing needs to understand planetary system processes and build accurate prediction models. One essential technology to accomplish these goals is the integration of multiple source data. For this integration, image registration and fusion represent the first steps and need to be performed with very high accuracy. In this paper, we describe studies performed in both image registration and fusion, including a modular framework that was built to describe registration algorithms, a Web-based image registration toolbox, and the comparison of several image fusion techniques using data from the EO-1/ALI and Hyperion sensors
Keywords: ALI; EO-1; fusion studies; geophysical signal processing; Hyperion sensors; image registration; Internet; multiple remote sensing data; multiple source data; Remote sensing; Web-based image registration toolbox

Integrated Motion Detection and Tracking for Visual Surveillance - Abdelkader, M.F.; Chellapa, Rama; Qinfen Zheng; Chan, A.L. (Computer Vision Systems, 2006 ICVS '06. IEEE International Conference on, 2006)
Visual surveillance systems have gained a lot of interest in the last few years. In this paper, we present a visual surveillance system that is based on the integration of motion detection and visual tracking to achieve better performance. Motion detection is achieved using an algorithm that combines temporal variance with background modeling methods. The tracking algorithm combines motion and appearance information into an appearance model and uses a particle filter framework for tracking the object in subsequent frames. The systems was tested on a large ground-truthed data set containing hundreds of color and FLIR image sequences. A performance evaluation for the system was performed and the average evaluation results are reported in this paper.

Integrating Video Information over Time. Example: Face Recognition from Video - Krüger,Volker; Zhou,Shaohua; Chellapa, Rama (Cognitive Vision SystemsCognitive Vision Systems, 2006)
The ability to integrate information over time in order to come to a conclusion is a strength of cognitive systems. It allows the system, e.g., to 1 verify insecure observations: This is the case when data is noisy or of low-quality, or if conditions in general are non-optimal. 2 exploit general knowledge about spatio-temporal relations: This allows the system to exploit the specific dynamics of an object as an additional feature for, e.g., recognition, interpretation and prediction of actions of other agents. 3 In general, using dynamics allows the system to recursively generate and verify hypotheses for object and scene interpretation and to generate warnings when ‘implausible’ hypotheses occur or to circumvent them altogether. We have studied the effectiveness of temporal integration for recognition purposes by using the face recognition as an example study case. Face recognition is a prominent problem and has been studied more extensively than almost any other recognition problem. An observation is that face recognition works well in ideal conditions. If those conditions, however, are not met, then all present algorithms break down disgracefully. This problem appears to be general to all vision techniques that intend to extract visual information out of low-SNR image data. It is exactly a strength of cognitive systems that they are able to cope with non-ideal situations. In this chapter we will deal with this problem.

Invariant Geometric Representation of 3D Point Clouds for Registration and Matching - Biswas,S.; Aggarwal,G.; Chellapa, Rama (Image Processing, 2006 IEEE International Conference on, 2006)
Though implicit representations of surfaces have often been used for various computer graphics tasks like modeling and morphing of objects, it has rarely been used for registration and matching of 3D point clouds. Unlike in graphics, where the goal is precise reconstruction, we use isosurfaces to derive a smooth and approximate representation of the underlying point cloud which helps in generalization. Implicit surfaces are generated using a variational interpolation technique. Implicit function values on a set of concentric spheres around the 3D point cloud of object are used as features for matching. Geometric-invariance is achieved by decomposing implicit values based feature set into various spherical harmonics. The decomposition provides a compact representation of 3D point clouds while achieving rotation invariance
Keywords: 3D; cloud; computer; function; geometric; graphics; geophysical; graphics; image; Interpolation; matching; image; point; processing; image; reconstruction; image; registration; image; registration; implicit; representation; interpolation; representation; variational; signal; technique; clouds; computer; value; invariant

Issues in writing a parallel compiler starting from a serial compiler - Tzannes,A.; Barua,R.; Caragea,G.; Vishkin, Uzi (draft. Technical report, University of Maryland Institute for Advanced Compuer Studies, 2006)

Key Frame-Based Activity Representation Using Antieigenvalues - Cuntoor,Naresh; Chellapa, Rama (Computer Vision – ACCV 2006Computer Vision – ACCV 2006, 2006)
Many activities may be characterized by a sequence of key frames that are related to important changes in motion rather than dominant characteristics that persist over a long sequence of frames. To detect such changes, we define a transformation operator at every time instant, which relates the past to the future states. One of the useful quantities associated with numerical range of an operator is the eigenvalue. In the literature, eigenvalue-based approaches have been studied extensively for many modeling tasks. These rely on gross properties of the data and are not suitable to detect subtle changes. We propose an antieigenvalue – based measure to detect key frames. Antieigenvalues depend critically on the turning of the operator, whereas eigenvalues represent the amount of dilation along the eigenvector directions aligned with the direction of maximum variance. We demonstrate its application to activity modeling and recognition using two datasets: a motion capture dataset and the UCF human action dataset.

Machining feature-based similarity assessment algorithms for prismatic machined parts - Cardone, Antonio; Gupta, Satyandra K.; Deshmukh,Abhijit; Karnik,Mukul (Computer-Aided Design, 2006)
This paper presents algorithms for identifying machined parts in a database that are similar to a given query part based on machining features. In this paper we only consider parts that are machined on 3-axis machining centers. We utilize reduced feature vectors consisting of machining feature access directions, feature types, feature volumes, feature dimensional tolerances and feature group cardinality as a basis for assessing shape similarity. We have defined a distance function between two sets of reduced feature vectors to assess the similarity between them from the machining effort point of view. To assess the similarity between the two parts, one set of reduced feature vectors is transformed in space using rigid body transformations with respect to the other set such that the distance between them is minimized. The distance between the two sets of aligned reduced feature vectors is used as a measure of similarity between the two parts. The existing machined parts are rank ordered based on the value of the distance with respect to the query part. The cost of previously machined parts that have a very small distance from the query part can be used as a basis for estimating the cost of machining the new part.
Keywords: Feature vector alignment; Machining features; Similarity assessment

Measuring human movement for biomechanical applications using markerless motion capture - Mündermann, L.; Corazza, S.; Chaudhari, A.M.; Andriacchi, T.P.; Sundaresan, A.; Chellapa, Rama (Proceedings of SPIE, 2006)
Modern biomechanical and clinical applications require the accurate capture of normal and pathological humanmovement without the artifacts associated with standard marker-based motion capture techniques such as soft tissue artifacts and the risk of artificial stimulus of taped-on or strapped-on markers. In this study, the need for new markerless human motion capture methods is discussed in view of biomechanical applications. Three different approaches for estimating human movement from multiple image sequences were explored. The first two approaches tracked a 3D articulated model in 3D representations constructed from the image sequences, while the third approach tracked a 3D articulated model in multiple 2D image planes. The three methods are systematically evaluated and results for real data are presented. The role of choosing appropriate technical equipment and algorithms for accurate markerless motion capture is critical. The implementation of this new methodology offers the promise for simple, time-efficient, and potentially more meaningful assessments of human movement in research and clinical practice.

The metacognitive loop I: Enhancing reinforcement learning with metacognitive monitoring and control for improved perturbation tolerance - Anderson,M. L; Oates,T.; Chong,W.; Perlis, Don (Journal of Experimental & Theoretical Artificial Intelligence, 2006)

Method and System for Object Surveillance and Real Time Activity Recognition - Yang Ran; Chellapa, Rama; Qinfen Zheng (2006)
Method and system for objects surveillance and real-time activity recognition is based on analysis of spatio-temporal images of individuals under surveillance where a spatio-temporal volume occupied by each individual is decomposed by crossing the same at specific heights to form 2-dimensional slices, each containing representation of trajectory of the motion of corresponding portions of the individual body. The symmetry of the trajectories (Gait DNA) is analyzed and classified to generate data indicative of a type of activity of the individual based on the symmetry or asymmetry of the Gait DNA in each 2-dimensional slice. An effective occlusion handling ability is implemented which permits to restore the occluded silhouette of an individual.

Microbial diversity in the era of genomics - Rita R Colwell (SYMPOSIA-SOCIETY FOR GENERAL MICROBIOLOGY, 2006)

Model based verification and validation of distributed control architectures - Ray,A.; Cleaveland, Rance; Jiang,S.; Fuhrman,T. (Proceedings of Convergence Convergence International Congress and Exposition on Transportation Electronics, Detroit, USA, 2006)

Model-Based Approaches - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
The model based approaches aim to derive the movement of the torso and/or the legs. The distinction of a structural approach is one which uses static parameters illustrated in Fig. 6.1(a) whereas a model can be the (relative) motion of the angles (α, β, and ϕ) between the limbs, shown in Fig. 6.1(b). As earlier, these angles can also be measured relative to vertical.

Modeling Age Progression in Young Faces - Ramanathan,N.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2006 IEEE Computer Society Conference on, 2006)
We propose a craniofacial growth model that characterizes growth related shape variations observed in human faces during formative years. The model draws inspiration from the #145;revised #146; cardioidal strain transformation model proposed in psychophysical studies related to craniofacial growth. The model takes into account anthropometric evidences collected on facial growth and hence is in accordance with the observed growth patterns in human faces across years. We characterize facial growth by means of growth parameters defined over facial landmarks often used in anthropometric studies. We illustrate how the age-based anthropometric constraints on facial proportions translate into linear and non-linear constraints on facial growth parameters and propose methods to compute the optimal growth parameters. The proposed craniofacial growth model can be used to predict one #146;s appearance across years and to perform face recognition across age progression. This is demonstrated on a database of age separated face images of individuals under 18 years of age.

Modeling and Simulation of the Escalation Archetype in Computer Security - Rosenfeld,S. N.; Rus,I.; Michel Cukier (Symposium on Simulation Software Security (SSSS 06), 2006)
To support decision-making for mitigating computer security risks, we developed and used a system dynamics model of security aspects of an enterprise system. We describe the notion of archetypes in general and the escalation archetype specifically, showing how it can arise in computer security. We show the effects of this instance of escalation through simulation of our model, consider the effects of changes in the simulation, and discuss the prognoses drawn from the archetype literature and their applicability to security.

Modeling the Symptomatic Fixes Archetype in Enterprise Computer Security - Rosenfeld,S. N.; Rus,I.; Michel Cukier (2006)
To support decision-making for security-risk mitigation and the appropriate selection of security countermeasures, we propose a system dynamics model of the security aspects of an enterprise system. We developed such an executable model, incorporating the concept of archetypes. We present here one archetype for computer security, namely symptomatic fixes (or shifting the burden). Using simulation, we show one instance of how this archetype can be used for recognizing and diagnosing typical situations, as well as for fixing problems. The global effects of changes and behavioral trends are examined, and other instances of symptomatic fixes in security are described as well
Keywords: business data processing; decision making; decision-making; enterprise computer security; human factors; security of data; security-risk mitigation; symptomatic fixes archetype modeling; system dynamics model; system modeling

Models for Advancing PRAM and Other Algorithms into Parallel Programs for a PRAM-On-Chip Platform - Vishkin, Uzi; Caragea,George C.; Lee,Bryant (Technical Reports from UMIACS, UMIACS-UMIACS-TR-2006-21, 2006)
A bold vision that guided this work is as follows: (i) a parallel algorithms and programming course could become a standard course in every undergraduate computer science program, and (ii) this course could be coupled with a so-called PRAM-On-Chip architecture --- a commodity high-end multi-core computer architecture.In fact, the current paper is a tutorial on how to convert PRAM algorithms into efficient PRAM-On-Chip programs. Coupled with a text on PRAM algorithms as well as an available PRAM-On-Chip tool-chain, comprising a compiler and a simulator, the paper provides the missing link for upgrading a standard theoretical PRAM algorithms class to a parallel algorithms and programming class. Having demonstrated that such a course could cover similar programming projects and material to what is covered by a typical first serial algorithms and programming course, the paper suggests that parallel programming in the emerging multi-core era does not need to be more difficult than serial programming. If true, a powerful answer to the so-called parallel programming open problem is being provided. This open problem is currently the main stumbling block for the industry in getting the upcoming generation of multi-core architectures to improve single task completion time using easy-to-program application programmer interfaces. Known constraints of this open problem, such as backwards compatibility on serial code, are also addressed by the overall approach. More concretely, a widely used methodology for advancing parallel algorithmic thinking into parallel algorithms is revisited, and is extended into a methodology for advancing parallel algorithms to PRAM-On-Chip programs. A performance cost model for the PRAM-On-Chip is also presented. It uses as complexity metrics the length of sequence of round trips to memory (LSRTM) and queuing delay (QD) from memory access queues, in addition to standard PRAM computation costs. Highlighting the importance of LSRTM in determining performance is another contribution of the paper. Finally, some alternatives to PRAM algorithms, which, on one hand, are easier-to-think, but, on the other hand, suppress more architecture details, are also discussed.
Keywords: Technical Report

Molecular Characterization of Serine-, Alanine-, and Proline-Rich Proteins of Trypanosoma cruzi and Their Possible Role in Host Cell Infection - Baida,Renata C. P.; Santos,Marcia R. M.; Carmo,Mirian S.; Yoshida,Nobuko; Ferreira,Danielle; Ferreira,Alice Teixeira; El Sayed,Najib M.; Andersson,Bjorn; da Silveira,Jose Franco (Infect. Immun., 2006)
We previously reported the isolation of a novel protein gene family, termed SAP (serine-, alanine-, and proline-rich protein), from Trypanosoma cruzi. Aided by the availability of the completed genome sequence of T. cruzi, we have now identified 39 full-length sequences of SAP, six pseudogenes and four partial genes. SAPs share a central domain of about 55 amino acids and can be divided into four groups based on their amino (N)- and carboxy (C)-terminal sequences. Some SAPs have conserved N- and C-terminal domains encoding a signal peptide and a glycosylphosphatidylinositol anchor addition site, respectively. Analysis of the expression of SAPs in metacyclic trypomastigotes by two-dimensional electrophoresis and immunoblotting revealed that they are likely to be posttranslationally modified in vivo. We have also demonstrated that some SAPs are shed into the extracellular medium. The recombinant SAP exhibited an adhesive capacity toward mammalian cells, where binding was dose dependent and saturable, indicating a possible ligand-receptor interaction. SAP triggered the host cell Ca2+ response required for parasite internalization. A cell invasion assay performed in the presence of SAP showed inhibition of internalization of the metacyclic forms of the CL strain. Taken together, these results show that SAP is involved in the invasion of mammalian cells by metacyclic trypomastigotes, and they confirm the hypothesis that infective trypomastigotes exploit an arsenal of surface glycoproteins and shed proteins to induce signaling events required for their internalization.

Motion Based Correspondence for 3D Tracking of Multiple Dim Objects - Veeraraghavan,A.; Srinivasan, M.; Chellapa, Rama; Baird, E.; Lamont, R. (Acoustics, Speech and Signal Processing, 2006. ICASSP 2006 Proceedings. 2006 IEEE International Conference on, 2006)
Tracking multiple objects in a video is a demanding task that is frequently encountered in several systems such as surveillance and motion analysis. Ability to track objects in 3D requires the use of multiple cameras. While tracking multiple objects using multiples video cameras, establishing correspondence between objects in the various cameras is a nontrivial task. Specifically, when the targets are dim or are very far away from the camera, appearance cannot be used in order to establish this correspondence. Here, we propose a technique to establish correspondence across cameras using the motion features extracted from the targets, even when the relative position of the cameras is unknown. Experimental results are provided for the problem of tracking multiple bees in natural flight using two cameras. The reconstructed 3D flight paths of the bees show some interesting flight patterns
Keywords: 3D; analysis; motion; analysis; video; based; cameras; feature; correspondence; motion; dim; extraction; image; extraction; multiple; features; MOTION; objects; video; processing; signal; tracking; motion

Moving Object Verification from Airborne Video - Yue,Zhanfeng; Chellapa, Rama; Guarino, D. (Computer Vision Systems, 2006 ICVS '06. IEEE International Conference on, 2006)
This paper presents an end-to-end verification system for moving objects in airborne video. Lacking prior training data, the object information is collected on the fly from a short real-time learning sequence. Using a sample selection module, the system selects samples from the learning sequence and stores them in an exemplar database. To handle appearance change due to potentially large aspect angle variations, a homography-based view synthesis method is used to generate a novel view of each image in the exemplar database at the same pose as the query object in each frame of a query sequence. A spatial match score is obtained using a Distance Transform to compare the novel view and query object. After looping over all query frames, the set of match scores is passed to a temporal analysis module to examine the behavior of the query object, and calculate a final likelihood. Very good verification performance is achieved over thousands of trials for both color and infrared video sequences using the proposed system.

Multi-camera Tracking of Articulated Human Motion Using Motion and Shape Cues - Sundaresan,Aravind; Chellapa, Rama (Computer Vision – ACCV 2006Computer Vision – ACCV 2006, 2006)
We present a framework and algorithm for tracking articulated motion for humans. We use multiple calibrated cameras and an articulated human shape model. Tracking is performed using motion cues as well as image-based cues (such as silhouettes and “motion residues” hereafter referred to as spatial cues,) as opposed to constructing a 3D volume image or visual hulls. Our algorithm consists of a predictor and corrector: the predictor estimates the pose at the t + 1 using motion information between images at t and t + 1. The error in the estimated pose is then corrected using spatial cues from images at t + 1. In our predictor, we use robust multi-scale parametric optimisation to estimate the pixel displacement for each body segment. We then use an iterative procedure to estimate the change in pose from the pixel displacement of points on the individual body segments. We present a method for fusing information from different spatial cues such as silhouettes and “motion residues” into a single energy function. We then express this energy function in terms of the pose parameters, and find the optimum pose for which the energy is minimised.

Nuclear Envelope Dystrophies Show a Transcriptional Fingerprint Suggesting Disruption of Rb–MyoD Pathways in Muscle Regeneration - Bakay,Marina; Wang,Zuyi; Melcon,Gisela; Schiltz,Louis; Xuan,Jianhua; Zhao,Po; Sartorelli,Vittorio; Seo,Jinwook; Pegoraro,Elena; Angelini,Corrado; Shneiderman, Ben; Escolar,Diana; et al. (BrainBrain, 2006)
Mutations of lamin A/C (LMNA) cause a wide range of human disorders, including progeria, lipodystrophy, neuropathies and autosomal dominant Emery–Dreifuss muscular dystrophy (EDMD). EDMD is also caused by X-linked recessive loss-of-function mutations of emerin, another component of the inner nuclear lamina that directly interacts with LMNA. One model for disease pathogenesis of LMNA and emerin mutations is cell-specific perturbations of the mRNA transcriptome in terminally differentiated cells. To test this model, we studied 125 human muscle biopsies from 13 diagnostic groups (125 U133A, 125 U133B microarrays), including EDMD patients with LMNA and emerin mutations. A Visual and Statistical Data Analyzer (VISDA) algorithm was used to statistically model cluster hierarchy, resulting in a tree of phenotypic classifications. Validations of the diagnostic tree included permutations of U133A and U133B arrays, and use of two probe set algorithms (MAS5.0 and MBEI). This showed that the two nuclear envelope defects (EDMD LMNA, EDMD emerin) were highly related disorders and were also related to fascioscapulohumeral muscular dystrophy (FSHD). FSHD has recently been hypothesized to involve abnormal interactions of chromatin with the nuclear envelope. To identify disease-specific transcripts for EDMD, we applied a leave-one-out (LOO) cross-validation approach using LMNA patient muscle as a test data set, with reverse transcription–polymerase chain reaction (RT–PCR) validations in both LMNA and emerin patient muscle. A high proportion of top-ranked and validated transcripts were components of the same transcriptional regulatory pathway involving Rb1 and MyoD during muscle regeneration (CRI-1, CREBBP, Nap1L1, ECREBBP/p300), where each was specifically upregulated in EDMD. Using a muscle regeneration time series (27 time points) we develop a transcriptional model for downstream consequences of LMNA and emerin mutations. We propose that key interactions between the nuclear envelope and Rb and MyoD fail in EDMD at the point of myoblast exit from the cell cycle, leading to poorly coordinated phosphorylation and acetylation steps. Our data is consistent with mutations of nuclear lamina components leading to destabilization of the transcriptome in differentiated cells.
Keywords: EDMD = Emery–Dreifuss muscular dystrophy; emerin; Emery-Dreifuss muscular dystrophy; FSHD = fascioscapulohumeral muscular dystrophy; IDG = individual discriminatory genes; JDG = jointly discriminatory genes; lamin A/C; LGMD = limb-girdle muscular dystrophy; LOO = leave-one-out; RT–PCR = reverse transcription–polymerase chain reaction; VISDA = Visual and Statistical Data Analyzer; Skeletal muscle; wFC = weighted Fisher criterion

Observations about software development for high end computing - Carver, J. C; Hochstein, L. M; Kendall,R. P; Nakamura, T.; Zelkowitz, Marvin V; Basili, Victor R.; Post,D. E (CTWatch Quarterly, 2006)
In this paper, we have summarized our findings from a series of case studies conducted with ten ASC and MP Codes as a series of observations. Due to different environments in which each code is developed, some of the observations are consistent across code teams while others vary across code teams. Overall, we found high consistency among the ASC Codes and the MP Codes. Due to the different environments and foci of these projects, this result is both surprising and positive. In addition, despite the fact that a large majority of the developers on these teams have little or no formal training in software engineering, they have been able to make use of some basic software engineering principles. Further education and motivation could increase the use of these principles and further increase the quality of scientific and engineering software that has already demonstrated its value.Based on the positive results thus far, we have plans to conduct additional case studies to gather more data in support of or in contradiction to the observations presented in this paper. In future case studies, we will strive to investigate codes from additional domains, thereby allowing broader, more inclusive conclusions to be drawn.

Oceans And Health: Pathogens In The Marine Environment - Belkin,Shimshon; Rita R Colwell (Springer, 2006)
The release of non-disinfected wastewaters into the marine environment is a common worldwide practice, in under-developed as well as in highly developed countries. Consequently, the seas are constantly infused with wastewater bacteria, among them highly pathogenic ones. In view of the public health significance of this phenomenon, it is surprising how little is actually known concerning the fate of such bacteria once they enter the sea. While numerous studies have addressed the effects of various environmental parameters on colony formation, many of them actually ignore the fact that bacteria can retain viability and infectivity while losing colony-forming ability. Only in recent years have efforts also been directed at unraveling the mechanisms determining bacterial sensitivity or survival under these conditions. This, therefore, is one subject of Oceans and Health: Pathogens in the Marine Environment: the survival, infectivity, pathogenicity and viability of enteric bacteria in the sea. Chapters also detail the public health aspects of wastewater release, civil engineering and economic considerations, other sources of pathogens, and much more.
Keywords: Electronic books; Marine microbiology; Medical / Epidemiology; Medical / Microbiology; Nature / Animals / Marine Life; Pathogenic microorganisms; Science / Environmental Science; Science / Life Sciences / Biology; Science / Life Sciences / Marine Biology; Science / Life Sciences / Microbiology; Seawater/ microbiology

Opinion Analysis in Document Databases - Cesarano,C.; Dorr, Bonnie J; Picariello, A.; Reforgiato,D.; Sagoff,A.; V.S. Subrahmanian (Proc. AAAI Spring Symposium on Computational Approaches to Analyzing Weblogs, Stanford, CA, 2006)
There are numerous applications in which we would like toassess what opinions are being expressed in text documents. Forr example, Martha Stewart’s company may have wished to assess the degree of harshness of news articles about her in the recent past. Likewise, a World Bank official may wish to as- sess the degree of criticism of a proposed dam in Bangladesh. The ability to gauge opinion on a given topic is therefore of critical interest. In this paper, we develop a suite of algo- rithms which take as input, a set D of documents as well as a topic t, and gauge the degree of opinion expressed about topic t in the set D of documents. Our algorithms can return both a number (larger the number, more positive the opinion) as well as a qualitative opinion (e.g. harsh, complimentary). We as- sess the accuracy of these algorithms via human experiments and show that the best of these algorithms can accurately re- flect human opinions. We have also conducted performance experiments showing that our algorithms are computationally fast.

A parallel implicit method for the direct numerical simulation of wall-bounded compressible turbulence - Martin, M.P; Candler,Graham V. (Journal of Computational Physics, 2006)
A new second-order accurate implicit temporal numerical scheme for the direct numerical simulation of turbulent flows is presented. The formulation of the implicit method and the corresponding tunable parameters are introduced. The numerical simulation results are compared with the results given by explicit Runge–Kutta schemes, theoretical results, and published experimental and numerical data. An assessment of the accuracy and performance of the method to simulate turbulent flows is made for temporally decaying isotropic turbulence and subsonic and supersonic turbulent boundary layers. Whereas no significant advantage over typical explicit time integration methods are found for the incompressible flows; it is shown that the implicit scheme yields significant reduction in computer cost while assuring time-accurate solutions for compressible turbulence simulations.
Keywords: direct numerical simulation; Implicit time integration; Wall-bounded turbulent flow

PDR: A Performance Evaluation Method for Foreground-Background Segmentation Algorithms - Kim,K.; Chalidabhongse,T.H.; Harwood,D.; Davis, Larry S. (EURASIP Journal on Applied Signal Processing, 2006)
We introduce a performance evaluation methodologycalled Perturbation Detection Rate (PDR) analysis for measuring performance of foreground-background seg- mentation. It has some advantages over the commonly used Receiver Operation Characteristics (ROC) analy- sis. Specifically, it does not require foreground targets or knowledge of foreground distributions. It measures the sensitivity of a background subtraction algorithm in detecting possible low contrast targets against the background as a function of contrast, also depending on how well the model captures mixed (moving) back- ground events. We compare four background subtrac- tion algorithms using the methodology. The experimen- tal results show how PDR is used to measure perfor- mance with respect to detection sensitivity in interest- ing low contrast regions.

Physics-Based Detectors Applied to Long-Wave Infrared Hyperspectral Data - Broadwater,Joshua; Chellapa, Rama (CENTER FOR AUTOMATION RESEARCH, UNIVERSITY OF MARYLAND COLLEGE PARK, 2006)
Long-wave infrared (LWIR) hyperspectral image (HSI) data presents an interesting challenge for automatic target detection algorithms. LWIR HSI data is useful for both day and night operations, but weak signatures like disturbed soil can be problematic for standard matched-filter techniques. In this paper, we augment the standard matched-filter techniques with physics-based information particular to HSI data. Our results show that these physics-based detectors provide improved detection performance with quick processing times.
Keywords: *HYPERSPECTRAL IMAGERY; algorithms; AUTOMATIC; DETECTION; FAR INFRARED RADIATION; LOW STRENGTH; Matched filters; MILITARY OPERATIONS; NIGHT; OPTICS; SIGNATURES; SOILS; SPECTROMETERS; TARGET DETECTION

Postmodern internetwork architecture - Bhattacharjee, Bobby; Calvert,K.; Griffioen,J.; Spring, Neil; Sterbenz,J. P.G (ITTC-FY2006-TR-45030-01, Information and Telecommunication Center, The University of Kansas, 2006)
Network-layer innovation has proven surprisingly difficult, in part because internetworking protocols ignore com-peting economic interests and because a few protocols dominate, enabling layer violations that entrench technologies. Many shortcomings of today’s internetwork layer result from its inflexibility with respect to the policies of the stake- holders: users and service providers. The consequences of these failings are well-known: various hacks, layering violations, and overloadings are introduced to enforce policies and attempt to get the upper hand in various “tus- sles”. The result is a network that is increasingly brittle, hostile to innovation, vulnerable to attack, and insensitive to concerns about accountability and privacy. Our project aims to design, implement, and evaluate through daily use a minimalist internetwork layer and aux- iliary functionality that anticipates tussles and allows them to be played out in policy space, as opposed to in the packet-forwarding path. We call our approach postmodern internetwork architecture, because it is a reaction against many established network layer design concepts. The overall goal of the project is to make a larger portion of the network design space accessible without sacrificing the economy of scale offered by the unified Internet. We will use the postmodern architecture to explore basic architectural questions. These include: • What mechanisms should be supported by the network such that any foreseeable policy requirement can be explicitly addressed? • To what extent can routing and forwarding be isolated from each other while maintaining an efficient and usable network? • What forms of identity should be visible within the network, and what forms of accountability do different identities enable? • What mechanisms are needed to enable efficient access to cross-layer information and mechanisms such that lower layers can express their characteristics and upper layers can exert control downward? We plan to build and evaluate a complete end-to-end networking layer to help us understand feasible solutions to these questions. The Internet has fulfilled the potential of a complete generation of networking research by producing a global platform for innovation, commerce, and democracy. Unfortunately, the Internet also amply demonstrates the com- plexity and architectural ugliness that ensue when competing interests vie for benefits beyond those envisioned in the original design. This project is about redesigning the waist of the architectural hourglass to foster innovation, enhance security and accountability, and accomodate competing interests.

Principal components null space analysis for image and video classification - Vaswani, N.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2006)
We present a new classification algorithm, principal component space analysis (PCNSA), which is designed for classification problems like object recognition where different classes have unequal and nonwhite noise covariance matrices. PCNSA first obtains a principal components subspace (PCA space) for the entire data. In this PCA space, it finds for each class "i", an Mi-dimensional subspace along which the class' intraclass variance is the smallest. We call this subspace an approximate space (ANS) since the lowest variance is usually "much smaller" than the highest. A query is classified into class "i" if its distance from the class' mean in the class' ANS is a minimum. We derive upper bounds on classification error probability of PCNSA and use these expressions to compare classification performance of PCNSA with that of subspace linear discriminant analysis (SLDA). We propose a practical modification of PCNSA called progressive-PCNSA that also detects "new" (untrained classes). Finally, we provide an experimental comparison of PCNSA and progressive PCNSA with SLDA and PCA and also with other classification algorithms-linear SVMs, kernel PCA, kernel discriminant analysis, and kernel SLDA, for object recognition and face recognition under large pose/expression variation. We also show applications of PCNSA to two classification problems in video-an action retrieval problem and abnormal activity detection.
Keywords: approximate null space; classification error probability; face recognition; image classification; object recognition; principal components null space analysis; subspace linear discriminant analysis; video classification; image classification; principal component a; Automated; Principal Component Analysis; Signal Processing; Computer-Assisted; Information Storage and Retrieval; Models; Computer-Assisted; Video Recording; Statistical; Pattern Recognition

Probabilistic I/O automata: Theories of two equivalences - Stark,E.; Cleaveland, Rance; Smolka,S. (CONCUR 2006–Concurrency Theory, 2006)

Query Rewriting in the Semantic Web7 - Vidal,Maria Esther; Raschid, Louiqa; Marquez,Natalia; Cardenas,Marelis; Yao Wu (Data Engineering Workshops, 22nd International Conference on, 2006)
The widespread explosion of Web accessible resources has lead to a new challenge of locating all relevant resources and identifying the best ones to answer a query. This challenge has to address the difficult task of ranking the resources based on user needs, as well as the more expensive computational task of determining all the solutions to answer a query. In this paper, we define a Top K problem for query rewriting on the Semantic Web. We first introduce a three level data model composed of the ontology level, the physical level of the physical resources, and the data level composed of the entries in the different resources. We present a query language for Top K navigational queries over ontology concepts. We then sketch the outline of an efficient search algorithm to compute an approximation of the Top K rewriting options to produce source paths among the physical resources. We briefly discuss the results of an experimental study

Recognition of Multi-Object Events Using Attribute Grammars - Joo,Seong-Wook; Chellapa, Rama (Image Processing, 2006 IEEE International Conference on, 2006)
We present a method for representing and recognizing visual events using attribute grammars. In contrast to conventional grammars, attribute grammars are capable of describing features that are not easily represented by finite symbols. Our approach handles multiple concurrent events involving multiple entities by associating unique object identification labels with multiple event threads. Probabilistic parsing and probabilistic conditions on the attributes are used to achieve a robust recognition system. We demonstrate the effectiveness of our method for the task of recognizing vehicle casing in parking lots and events occurring in an airport tarmac
Keywords: attribute; event; grammar; multiobject; grammars; image; identification; label; probabilistic; parsing; attribute; recognition; object; recognition; probability; representation; object

Reflecting on Health: A System for Students to Monitor Diet and Exercise - Brown, Brandon; Marshini Chetty; Grimes, Andrea; Harmon, Ellie (SIGCHI EA '06, 2006)
Using an iterative design process, we designed and evaluated a system for college students to encourage the development and maintenance of healthy diet and exercise habits. The system has three components: a camera phone application to support photographic diet and exercise journaling, an automatic workout tracking application for exercise machines in the gym, and a visualization application to support users as they reflect on their diet and exercise activities.
Keywords: diet; exercise; journaling; mobile phone; Visualization

Retroviral DNA Integration: Viral and Cellular Determinants of Target-Site Selection - Lewinski,Mary K; Yamashita,Masahiro; Emerman,Michael; Ciuffi,Angela; Marshall,Heather; Crawford,Gregory; Collins,Francis; Shinn,Paul; Leipzig,Jeremy; Hannenhalli, Sridhar; Berry,Charles C; Ecker,Joseph R; et al. (PLoS PathogPLoS Pathog, 2006)
Retroviruses differ in their preferences for sites for viral DNA integration in the chromosomes of infected cells. Human immunodeficiency virus (HIV) integrates preferentially within active transcription units, whereas murine leukemia virus (MLV) integrates preferentially near transcription start sites and CpG islands. We investigated the viral determinants of integration-site selection using HIV chimeras with MLV genes substituted for their HIV counterparts. We found that transferring the MLV integrase (IN) coding region into HIV (to make HIVmIN) caused the hybrid to integrate with a specificity close to that of MLV. Addition of MLV gag (to make HIVmGagmIN) further increased the similarity of target-site selection to that of MLV. A chimeric virus with MLV Gag only (HIVmGag) displayed targeting preferences different from that of both HIV and MLV, further implicating Gag proteins in targeting as well as IN. We also report a genome-wide analysis indicating that MLV, but not HIV, favors integration near DNase I–hypersensitive sites (i.e., +/− 1 kb), and that HIVmIN and HIVmGagmIN also favored integration near these features. These findings reveal that IN is the principal viral determinant of integration specificity; they also reveal a new role for Gag-derived proteins, and strengthen models for integration targeting based on tethering of viral IN proteins to host proteins.

Robust ego-motion estimation and 3-D model refinement using surface parallax - Agrawal,A.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2006)
We present an iterative algorithm for robustly estimating the ego-motion and refining and updating a coarse depth map using parametric surface parallax models and brightness derivatives extracted from an image pair. Given a coarse depth map acquired by a range-finder or extracted from a digital elevation map (DEM), ego-motion is estimated by combining a global ego-motion constraint and a local brightness constancy constraint. Using the estimated camera motion and the available depth estimate, motion of the three-dimensional (3-D) points is compensated. We utilize the fact that the resulting surface parallax field is an epipolar field, and knowing its direction from the previous motion estimates, estimate its magnitude and use it to refine the depth map estimate. The parallax magnitude is estimated using a constant parallax model (CPM) which assumes a smooth parallax field and a depth based parallax model (DBPM), which models the parallax magnitude using the given depth map. We obtain confidence measures for determining the accuracy of the estimated depth values which are used to remove regions with potentially incorrect depth estimates for robustly estimating ego-motion in subsequent iterations. Experimental results using both synthetic and real data (both indoor and outdoor sequences) illustrate the effectiveness of the proposed algorithm.
Keywords: 3D model refinement; algorithms; Artificial intelligence; Automated; Subtraction Technique; Computer-Assisted; Imaging; constant parallax model; depth based parallax model; digital elevation map; epipolar field; Image Enhancement; Image Interpretation; iterative algorithm; iterative methods; Motion estimation; robust ego-motion estimation; smooth parallax field; surface parallax; Three-Dimensional; Information Storage and Retrieval; Pattern Recognition

A robust maximum completion time measure for scheduling - Charikar,Moses; Khuller, Samir (Proceedings of the seventeenth annual ACM-SIAM symposium on Discrete algorithm, 2006)
One popular measure for evaluating the performance of scheduling algorithms, is the maximum response time of any job (makespan). Typically the objective is to find a schedule that minimizes the maximum response time over all jobs. One drawback of this measure is that a relatively small number of jobs in the request set could cause the maximum response time to be very high. Thus, this measure reflects local rather than global properties of the request set. In this paper we consider a robust generalization of this measure. Our goal is to minimize T, such that a given fraction of jobs can be scheduled with a response time of at most T. We demonstrate the applicability of this measure in the context of broadcast scheduling. We show that in the online setting no constant factor online approximation is possible for the problem of minimizing the maximum response time for a given fraction of jobs in the context of broadcast scheduling. We give a factor 5, polynomial time offline approximation algorithm for the problem of minimizing the maximum response time for a given fraction of jobs in the context of broadcast scheduling.

Seasonal Cholera Caused by Vibrio Cholerae Serogroups O1 and O139 in the Coastal Aquatic Environment of Bangladesh - Alam,Munirul; Hasan,Nur A.; Sadique,Abdus; Bhuiyan,N. A.; Ahmed,Kabir U.; Nusrin,Suraia; Nair,G. Balakrish; Siddique,A. K.; Sack,R. Bradley; Sack,David A.; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2006)
Since Vibrio cholerae O139 first appeared in 1992, both O1 El Tor and O139 have been recognized as the epidemic serogroups, although their geographic distribution, endemicity, and reservoir are not fully understood. To address this lack of information, a study of the epidemiology and ecology of V. cholerae O1 and O139 was carried out in two coastal areas, Bakerganj and Mathbaria, Bangladesh, where cholera occurs seasonally. The results of a biweekly clinical study (January 2004 to May 2005), employing culture methods, and of an ecological study (monthly in Bakerganj and biweekly in Mathbaria from March 2004 to May 2005), employing direct and enrichment culture, colony blot hybridization, and direct fluorescent-antibody methods, showed that cholera is endemic in both Bakerganj and Mathbaria and that V. cholerae O1, O139, and non-O1/non-O139 are autochthonous to the aquatic environment. Although V. cholerae O1 and O139 were isolated from both areas, most noteworthy was the isolation of V. cholerae O139 in March, July, and September 2004 in Mathbaria, where seasonal cholera was clinically linked only to V. cholerae O1. In Mathbaria, V. cholerae O139 emerged as the sole cause of a significant outbreak of cholera in March 2005. V. cholerae O1 reemerged clinically in April 2005 and established dominance over V. cholerae O139, continuing to cause cholera in Mathbaria. In conclusion, the epidemic potential and coastal aquatic reservoir for V. cholerae O139 have been demonstrated. Based on the results of this study, the coastal ecosystem of the Bay of Bengal is concluded to be a significant reservoir for the epidemic serogroups of V. cholerae.

Segmentation and Probabilistic Registration of Articulated Body Models - Sundaresan, A.; Chellapa, Rama (Pattern Recognition, 2006. ICPR 2006. 18th International Conference on, 2006)
There are different approaches to pose estimation and registration of different body parts using voxel data. We propose a general bottom-up approach in order to segment the voxels into different body parts. The voxels are first transformed into a high dimensional space which is the eigenspace of the Laplacian of the neighbourhood graph. We exploit the properties of this transformation and fit splines to the voxels belonging to different body segments in eigenspace. The boundary of the splines is determined by examination of the error in spline fitting. We then use a probabilistic approach to register the segmented body segments by utilizing their connectivity and prior knowledge of the general structure of the subjects. We present results on real data, containing both simple and complex poses. While we use human subjects in our experiment, the method is fairly general and can be applied to voxel-based registration of any articulated or non-rigid object composed of primarily 1-D parts
Keywords: (mathematics); and; approach; eigenspace; image; articulated; body; data; voxel-based; eigenfunctions; graph; estimation; probabilistic; fitting; voxel; graph; pose; models; bottom-up; registration; eigenvalues; registration; image; registration; spline; segmentation; neighbourhood; segmentation; probability; splines; theory; image

Sentence Trimming and Selection: Mixing and Matching - Zajic, David; Dorr, Bonnie J; Jimmy Lin; O'Leary, Dianne P.; Conroy,John M.; Schlesinger,Judith D. (DUC 06 Conference Proceedings, 2006)
We describe how components from two distinct multi-document summarization systems were combined. Twenty four possible combinations of components were considered. We observed some contrasts between conservative and aggressive sentence compression (i.e., trimming) in the context of multi-document summarization.

Septaplex PCR assay for rapid identification of Vibrio cholerae including detection of virulence and int SXT genes - Mantri,Chinmay K.; Mohapatra,Saswat S.; Ramamurthy,Thandavarayan; Ghosh,Raikamal; Rita R Colwell; Singh,Durg V. (FEMS Microbiology Letters, 2006)
In this study, we describe a septaplex PCR assay for rapid identification of Vibrio cholerae including detection of the virulence and intsxt genes. Conditions were optimized to amplify fragments of ISRrRNA (encoding for 16S–23S rRNA gene, Intergenic spacer regions), O1rfb (O1 serogroup specific rfb), O139rfb (O139 serogroup specific rfb), ctxA (cholera toxin subunit A), tcpA (toxin coregulated pilus), and intsxt (sxt integron) simultaneously in a single PCR. The septaplex PCR was evaluated using 211 strains of V. cholerae and six water samples for in situ testing. PCR results were correlated with genotype data obtained by individual PCR and slot-blot assays. The one-step PCR described here can be used to identify V. cholerae accurately and rapidly. Also, the virulence and intsxt genes can be simultaneously detected, providing a useful method for monitoring pathogenic, intsxt-positive and nonpathogenic, intsxt-negative V. cholerae serogroups both in the environment and clinical settings.
Keywords: DETECTION; intsxt; septaplex PCR; Vibrio cholerae; virulence

Shape Similarity Assessment Based On Face Alignment Using Attributed Applied Vectors. - Cardone, Antonio; Gupta, Satyandra K. (CAD Conference, 2006)

Shape-Regulated Particle Filtering for Tracking Non-Rigid Objects - Jie Shao; Chellapa, Rama; Porikli, F. (Image Processing, 2006 IEEE International Conference on, 2006)
This paper presents an active contour based algorithm for tracking non-rigid objects in heavily cluttered scenes. We decompose the non-rigid contour tracking problem into three subproblems: 2D motion estimation, deformation detection, and shape regulation. First, we employ a particle filter to estimate the affine transform parameters between successive frames. Second, by using a dynamic object model, we generate a probabilistic map of deformation to reshape its contour. Finally, we project the updated model onto a trained shape subspace to constrain deformations to be within possible object appearances. Our experiments show that the proposed algorithm significantly improves the performance of the tracker
Keywords: (numerical; 2D; algorithm; affine; based; contour; detection; dynamic; detection; motion; detection; parameter; estimation; active; estimation; object; estimation; particle; Filtering; filtering; probabilistic; filters; map; shape-regulation; affine; methods); tracking; model; nonrigid; MOTION; object; scenes; deformation; tracking; parameter; transform; cluttered; transforms; clutter; edge

Shared family calendars: Promoting symmetry and accessibility - Plaisant, Catherine; Clamage,Aaron; Hutchinson,Hilary Browne; Bederson, Benjamin B.; Druin, Allison (ACM Trans. Comput.-Hum. Interact., 2006)
We describe the design and use of a system facilitating the sharing of calendar information between remotely located, multi-generational family members. Most previous work in this area involves software enabling younger family members to monitor their parents. We have found, however, that older adults are equally if not more interested in the activities of younger family members. The major obstacle preventing them from participating in information sharing is the technology itself. Therefore, we developed a multi-layered interface approach that offers simple interaction to older users. In our system, users can choose to enter information into a computerized calendar or write it by hand on digital paper calendars. All of the information is automatically shared among everyone in the distributed family. By making the interface more accessible to older users, we promote symmetrical sharing of information among both older and younger family members. We present our participatory design process, describe the user interface, and report on an exploratory field study in three households of an extended family.
Keywords: calendar; digital paper; elderly; family technology; Home; layered interface; privacy; universal usability

Silhouette-Based Approaches - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
Of the current approaches, most are based on analysis of silhouettes. This is like the earlier analysis which concerned abstracting a walking subject from the background and then deriving set of measurements that describe the shape and motion of that silhouette in a sequence of images. This is similar in approach the classic computer vision approach to recognize objects by using shape descriptions of objects derived, say, by optimal thresholding.

A Software Architectural Approach to Security by Design - Ray,A.; Cleaveland, Rance (Computer Software and Applications Conference, 2006. COMPSAC '06. 30th Annual International, 2006)
This paper shows how an architecture description notation that has support for timed events can be used to provide a meta-language for specifying exact communication semantics. The advantages of such an approach is that a designer is made fully aware of the ramifications of her design choices so that an attacker can no longer take advantage of hidden assumptions
Keywords: architecture description notation; Clocks; communication semantics; Computer architecture; computer crime; computer security; Connectors; Costs; Degradation; Delay; Educational institutions; security design; security of data; Software architecture; software engineering

SParseval: Evaluation metrics for parsing speech - Roark,B.; Harper,M.; Charniak,E.; Dorr, Bonnie J; Johnson,M.; Kahn,J.; Liu,Y.; Ostendorf,M.; Hale,J.; Krasnyanskaya,A.; others (Proc. LREC, 2006)
While both spoken and written language processing stand to benefit from parsing, the standard Parseval metrics (Black et al., 1991) andtheir canonical implementation (Sekine and Collins, 1997) are only useful for text. The Parseval metrics are undefined when the words input to the parser do not match the words in the gold standard parse tree exactly, and word errors are unavoidable with automatic speech recognition (ASR) systems. To fill this gap, we have developed a publicly available tool for scoring parses that implements a variety of metrics which can handle mismatches in words and segmentations, including: alignment-based bracket evaluation, alignment-based dependency evaluation, and a dependency evaluation that does not require alignment. We describe the different metrics, how to use the tool, and the outcome of an extensive set of experiments on the sensitivity of the metrics.

Special Issue on Biometrics: Algorithms and Applications - Chellapa, Rama; Phillips, J.; Reynolds, D. (Proceedings of the IEEE, 2006)

Stabilization and Mosaicing of Airborne Videos - Ramachandran, M.; Chellapa, Rama (Image Processing, 2006 IEEE International Conference on, 2006)
We present an algorithm for stabilizing low-quality and low-resolution video sequences obtained from UAVs and MAVs flying over a predominantly planar terrain. The problem is important for the processing of videos captured from airborne platforms where most of the image region gives little information about the image-motion. The algorithm consists of approximately aligning the images using phase correlation, then refining the transformation parameters using available optical flow measurements and finally performing a minimization of the image difference by carefully selecting the image regions to make the iterations converge. In the second part of the paper, we describe an algorithm for camera ego-motion estimation by incorporating available metadata along with the video sequence. The availability of metadata such as IMU measurements provides a good initial solution for the camera orientation and helps the iterations converge faster by reducing the search space
Keywords: airborne; analysis; image; cameras; convergence; low-resolution; ego-motion; estimation; iterations; flow; measurement; video; mosaicing; camera; MOTION; resolution; image; segmentation; image; sequence; optical; sequences; video; stabilization; image; video; Videos

A Statistical Analysis of Attack Data to Separate Attacks - Michel Cukier; Berthier,R.; Panjwani,S.; Tan,S. (2006)
This paper analyzes malicious activity collected from a test-bed, consisting of two target computers dedicated solely to the purpose of being attacked, over a 109 day time period. We separated port scans, ICMP scans, and vulnerability scans from the malicious activity. In the remaining attack data, over 78% (i.e., 3,677 attacks) targeted port 445, which was then statistically analyzed. The goal was to find the characteristics that most efficiently separate the attacks. First, we separated the attacks by analyzing their messages. Then we separated the attacks by clustering characteristics using the K-Means algorithm. The comparison between the analysis of the messages and the outcome of the K-Means algorithm showed that 1) the mean of the distributions of packets, bytes and message lengths over time are poor characteristics to separate attacks and 2) the number of bytes, the mean of the distribution of bytes and message lengths as a function of the number packets are the best characteristics for separating attacks
Keywords: attack data statistical analysis; attack separation; computer crime; Data analysis; data mining; ICMP scans; K-Means algorithm; pattern clustering; port scans; statistical analysis; vulnerability scans

Structure From Planar Motion - Li,Jian; Chellapa, Rama (Image Processing, IEEE Transactions on, 2006)
Planar motion is arguably the most dominant type of motion in surveillance videos. The constraints on motion lead to a simplified factorization method for structure from planar motion when using a stationary perspective camera. Compared with methods for general motion , our approach has two major advantages: a measurement matrix that fully exploits the motion constraints is formed such that the new measurement matrix has a rank of at most 3, instead of 4; the measurement matrix needs similar scalings, but the estimation of fundamental matrices or epipoles is not needed. Experimental results show that the algorithm is accurate and fairly robust to noise and inaccurate calibration. As the new measurement matrix is a nonlinear function of the observed variables, a different method is introduced to deal with the directional uncertainty in the observed variables. Differences and the dual relationship between planar motion and planar object are also clarified. Based on our method, a fully automated vehicle reconstruction system has been designed
Keywords: algebra; road; analysis; matrix; camera; surveillance; directional; matrix; planar; MOTION; motion; stationary; perspective; processing; reconstruction; signal; system; image; uncertainty; measurement; vehicles; surveillance; video; videos; vehicle

Subjects Allied to Gait - Nixon, M.S.; Tan, T.; Chellapa, Rama (Human Identification Based on GaitHuman Identification Based on Gait, 2006)
There is considerable support for the notion that each person’s gait is unique. As we shall see, it has been observed in literature that people can be recognized by the way they walk. The same notion has been observed in medicine and biomechanics, though not in the context of biometrics but more as an assertion of individuality. Perhaps driven by these notions, though without reference to them, there has been work in psychology on the human ability to recognize each other by using gait. Those suffering myopia often state that they can use gait as a way of recognizing people. There is other evidence too, which suggests that each person’s gait is unique. People have also studied walking from medical and biomechanical perspectives, and this gives insight into how its properties can change which is of general interest in any biometrie deployment. We shall start with literature, with definitions of meaning.

Topic-focused multi-document summarization using an approximate oracle score - Conroy,John M.; Schlesinger,Judith D.; O'Leary, Dianne P. (Proceedings of the COLING/ACL on Main conference poster sessions, 2006)
We consider the problem of producing a multi-document summary given a collection of documents. Since most successful methods of multi-document summarization are still largely extractive, in this paper, we explore just how well an extractive method can perform. We introduce an "oracle" score, based on the probability distribution of unigrams in human summaries. We then demonstrate that with the oracle score, we can generate extracts which score, on average, better than the human summaries, when evaluated with ROUGE. In addition, we introduce an approximation to the oracle score which produces a system with the best known performance for the 2005 Document Understanding Conference (DUC) evaluation.

Toxigenic Vibrio Cholerae in the Aquatic Environment of Mathbaria, Bangladesh - Alam,Munirul; Sultana,Marzia; Nair,G. Balakrish; Sack,R. Bradley; Sack,David A.; Siddique,A. K.; Ali,Afsar; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2006)
Toxigenic Vibrio cholerae, rarely isolated from the aquatic environment between cholera epidemics, can be detected in what is now understood to be a dormant stage, i.e., viable but nonculturable when standard bacteriological methods are used. In the research reported here, biofilms have proved to be a source of culturable V. cholerae, even in nonepidemic periods. Biweekly environmental surveillance for V. cholerae was carried out in Mathbaria, an area of cholera endemicity adjacent to the Bay of Bengal, with the focus on V. cholerae O1 and O139 Bengal. A total of 297 samples of water, phytoplankton, and zooplankton were collected between March and December 2004, yielding eight V. cholerae O1 and four O139 Bengal isolates. A combination of culture methods, multiplex-PCR, and direct fluorescent antibody (DFA) counting revealed the Mathbaria aquatic environment to be a reservoir for V. cholerae O1 and O139 Bengal. DFA results showed significant clumping of the bacteria during the interepidemic period for cholera, and the fluorescent micrographs revealed large numbers of V. cholerae O1 in thin films of exopolysaccharides (biofilm). A similar clumping of V. cholerae O1 was also observed in samples collected from Matlab, Bangladesh, where cholera also is endemic. Thus, the results of the study provided in situ evidence for V. cholerae O1 and O139 in the aquatic environment, predominantly as viable but nonculturable cells and culturable cells in biofilm consortia. The biofilm community is concluded to be an additional reservoir of cholera bacteria in the aquatic environment between seasonal epidemics of cholera in Bangladesh.

Transcriptional Genomics Associates FOX Transcription Factors With Human Heart Failure - Hannenhalli, Sridhar; Putt,Mary E.; Gilmore,Joan M.; Wang,Junwen; Parmacek,Michael S.; Epstein,Jonathan A.; Morrisey,Edward E.; Margulies,Kenneth B.; Cappola,Thomas P. (Circulation, 2006)
Background— Specific transcription factors (TFs) modulate cardiac gene expression in murine models of heart failure, but their relevance in human subjects remains untested. We developed and applied a computational approach called transcriptional genomics to test the hypothesis that a discrete set of cardiac TFs is associated with human heart failure.Methods and Results— RNA isolates from failing (n=196) and nonfailing (n=16) human hearts were hybridized with Affymetrix HU133A arrays, and differentially expressed heart failure genes were determined. TF binding sites overrepresented in the −5-kb promoter sequences of these heart failure genes were then determined with the use of public genome sequence databases. Binding sites for TFs identified in murine heart failure models (MEF2, NKX, NF-AT, and GATA) were significantly overrepresented in promoters of human heart failure genes (P<0.002; false discovery rate 2% to 4%). In addition, binding sites for FOX TFs showed substantial overrepresentation in both advanced human and early murine heart failure (P<0.002 and false discovery rate <4% for each). A role for FOX TFs was supported further by expression of FOXC1, C2, P1, P4, and O1A in failing human cardiac myocytes at levels similar to established hypertrophic TFs and by abundant FOXP1 protein in failing human cardiac myocyte nuclei.Conclusions— Our results provide the first evidence that specific TFs identified in murine models (MEF2, NKX, NFAT, and GATA) are associated with human heart failure. Moreover, these data implicate specific members of the FOX family of TFs (FOXC1, C2, P1, P4, and O1A) not previously suggested in heart failure pathogenesis. These findings provide a crucial link between animal models and human disease and suggest a specific role for FOX signaling in modulating the hypertrophic response of the heart to stress in humans.

Trypanosoma cruzi mitochondrial maxicircles display species- and strain-specific variation and a conserved element in the non-coding region - Westenberger,Scott; Cerqueira,Gustavo; El‐Sayed, Najib M.; Zingales,Bianca; Campbell,David; Sturm,Nancy (BMC Genomics, 2006)
BACKGROUND:The mitochondrial DNA of kinetoplastid flagellates is distinctive in the eukaryotic world due to its massive size, complex form and large sequence content. Comprised of catenated maxicircles that contain rRNA and protein-coding genes and thousands of heterogeneous minicircles encoding small guide RNAs, the kinetoplast network has evolved along with an extreme form of mRNA processing in the form of uridine insertion and deletion RNA editing. Many maxicircle-encoded mRNAs cannot be translated without this post-transcriptional sequence modification.RESULTS:We present the complete sequence and annotation of the Trypanosoma cruzi maxicircles for the CL Brener and Esmeraldo strains. Gene order is syntenic with Trypanosoma brucei and Leishmania tarentolae maxicircles. The non-coding components have strain-specific repetitive regions and a variable region that is unique for each strain with the exception of a conserved sequence element that may serve as an origin of replication, but shows no sequence identity with L. tarentolae or T. brucei. Alternative assemblies of the variable region demonstrate intra-strain heterogeneity of the maxicircle population. The extent of mRNA editing required for particular genes approximates that seen in T. brucei. Extensively edited genes were more divergent among the genera than non-edited and rRNA genes. Esmeraldo contains a unique 236-bp deletion that removes the 5'-ends of ND4 and CR4 and the intergenic region. Esmeraldo shows additional insertions and deletions outside of areas edited in other species in ND5, MURF1, and MURF2, while CL Brener has a distinct insertion in MURF2.CONCLUSION:The CL Brener and Esmeraldo maxicircles represent two of three previously defined maxicircle clades and promise utility as taxonomic markers. Restoration of the disrupted reading frames might be accomplished by strain-specific RNA editing. Elements in the non-coding region may be important for replication, transcription, and anchoring of the maxicircle within the kinetoplast network.

Unconstrained face recognition - Zhou,S. Kevin; Chellapa, Rama; Zhao,Wenyi (Springer Science & Business, 2006)
Face recognition has been actively studied over the past decade and continues to be a big research challenge. Just recently, researchers have begun to investigate face recognition under unconstrained conditions. Unconstrained Face Recognition provides a comprehensive review of this biometric, especially face recognition from video, assembling a collection of novel approaches that are able to recognize human faces under various unconstrained situations. The underlying basis of these approaches is that, unlike conventional face recognition algorithms, they exploit the inherent characteristics of the unconstrained situation and thus improve the recognition performance when compared with conventional algorithms.Unconstrained Face Recognition is structured to meet the needs of a professional audience of researchers and practitioners in industry. This volume is also suitable for advanced-level students in computer science.
Keywords: Computer science; Computer vision; Computers / Computer Graphics; Computers / Computer Science; Computers / Computer Vision & Pattern Recognition; Computers / General; Computers / Image Processing; Computers / Information Technology; Computers / Information Theory; Computers / Interactive & Multimedia; Computers / Security / Cryptography; Computers / User Interfaces; Data encryption (Computer science); Data structures (Computer science); Electronic books; Human face recognition (Computer science); IMAGE PROCESSING; Image processing - Digital techniques; multimedia systems; Optical pattern recognition; Science / Life Sciences / Biology

Vehicle Fingerprinting Using Drive-By Sounds - Cevher, V.; Chellapa, Rama; Gurbuz, A.C.; Shah, F.; McClellan, J.H. (CENTER FOR AUTOMATION RESEARCH, UNIVERSITY OF MARYLAND COLLEGE PARK, 2006)
We estimate a vehicle's speed, width, and length by jointly estimating its acoustic wave-pattern using a single passive acoustic sensor that records the vehicle's drive-by noise. The acoustic wave-pattern is estimated using three envelope shape (ES) components, which approximate the shape of the received signal's power envelope. We incorporate the parameters of the ES components along with estimates of the vehicle engine RPM and number of cylinders to form a vehicle profile vector. This vector provides a compressed statistics that can be used for vehicle identification and classification. Vehicle speed estimation and classification results are provided using field data.
Keywords: *ACOUSTIC DETECTORS; *GROUND VEHICLES; *SIGNAL PROCESSING; ACOUSTIC DETECTION AND DETECTORS; AMPLITUDE; Interference; PASSIVE SYSTEMS; spatial distribution; STATISTICAL PROCESSES; SURFACE TRANSPORTATION AND EQUIPMENT; SYMPOSIA; WAVE PROPAGATION

Video Mensuration Using a Stationary Camera - Guo,Feng; Chellapa, Rama (Computer Vision – ECCV 2006Computer Vision – ECCV 2006, 2006)
This paper presents a method for video mensuration using a single stationary camera. The problem we address is simple, i.e., the mensuration of any arbitrary line segment on the reference plane using multiple frames with minimal calibration. Unlike previous solutions that are based on planar rectification, our approach is based on fitting the image of multiple concentric circles on the plane. Further, the proposed method aims to minimize the error in mensuration. Hence we can calculate the mensuration of the line segments not lying on the reference plane. Using an algorithm for detecting and tracking wheels of an automobile, we have implemented a fully automatic system for wheel base mensuration. The mensuration results are accurate enough that they can be used to determine the vehicle classes. Furthermore, we measure the line segment between any two points on the vehicle and plot them in top and side views.

View Invariance for Human Action Recognition - Parameswaran,Vasu; Chellapa, Rama (International Journal of Computer Vision, 2006)
This paper presents an approach for viewpoint invariant human action recognition, an area that has received scant attention so far, relative to the overall body of work in human action recognition. It has been established previously that there exist no invariants for 3D to 2D projection. However, there exist a wealth of techniques in 2D invariance that can be used to advantage in 3D to 2D projection. We exploit these techniques and model actions in terms of view-invariant canonical body poses and trajectories in 2D invariance space, leading to a simple and effective way to represent and recognize human actions from a general viewpoint. We first evaluate the approach theoretically and show why a straightforward application of the 2D invariance idea will not work. We describe strategies designed to overcome inherent problems in the straightforward approach and outline the recognition algorithm. We then present results on 2D projections of publicly available human motion capture data as well on manually segmented real image sequences. In addition to robustness to viewpoint change, the approach is robust enough to handle different people, minor variabilities in a given action, and the speed of aciton (and hence, frame-rate) while encoding sufficient distinction among actions.

View-invariant estimation of height and stride for gait recognition - BenAbdelkader,C.; Cutler, R.; Davis, Larry S. (Biometric Authentication, 2006)
We present a parametric method to automatically identify people in monocular low-resolution video by estimating the height and stride parameters of their walking gait. Stride parameters (stride length and cadence) are functions of body height, weight, and gender. Previous work has demonstrated effective use of these biometrics for identification and verification of people. In this paper, we show that performance is significantly improved by using height as an additional discriminant feature. Height is estimated by robustly segmenting the person from the background and fitting their apparent height to a time-dependent model. This method is correspondence-free and works with low-resolution images of people. It is also view-invariant, albeit performance is optimal in near fronto-parallel configurations. Identification accuracy is estimated at 47% for fronto-parallel sequences of 41 people, and 65% for non-fronto-parallel sequences of 17 people, compared with 18% and 51%, respectively, when only stride and cadence are used.

VoIP deregulation in South Africa: Implications for underserviced areas - Marshini Chetty; Blake, Edwin; McPhie, Ewan (Telecommunications Policy, 2006)
Several statutory restrictions have recently been lifted on the use of Voice over Internet Protocol (VoIP) in South Africa. Previously, VoIP could only be utilised by the incumbent telecommunications operator, Telkom, the Second National Operator (SNO) and under serviced area licensees (USALs). This means new opportunities and cost savings for both network service providers and consumers. However, in rural and remote regions, further liberalisation is required so that service providers can take advantage of wireless technologies to provide connectivity in these areas. This paper discusses the legislative environment in South Africa and around the world with respect to VoIP and Wireless Fidelity (WiFi). In addition, examples are provided of how these technologies have been combined to provide last mile solutions around the world and particularly in South Africa. The paper concludes that further liberalisation in the telecommunications environment in South Africa is required if the goal of providing affordable access in rural areas is to be attained. Specifically, it is recommended that wireless technologies be deregulated since the combination of VoIP and WiFi may benefit rural areas. Also, the paper finds that USALs may not be the right model for underserviced areas in South Africa. Lastly, it is apparent that applications drive development and dictate which technologies are relevant for rural areas.
Keywords: South Africa; VoIP; WiFi

Voting with Your Feet: An Investigative Study of the Relationship Between Place Visit Behavior and Preference - Jon Froehlich; Chen,Mike; Smith,Ian; Potter,Fred (UbiComp 2006: Ubiquitous Computing, 2006)
Real world recommendation systems, personalized mobile search, and online city guides could all benefit from data on personal place preferences. However, collecting explicit rating data of locations as users travel from place to place is impractical. This paper investigates the relationship between explicit place ratings and implicit aspects of travel behavior such as visit frequency and travel time. We conducted a four-week study with 16 participants using a novel sensor-based experience sampling tool, called My Experience (Me), which we developed for mobile phones. Over the course of the study Me was used to collect 3,458 in-situ questionnaires on 1,981 place visits. Our results show that, first, sensor-triggered experience sampling is a useful methodology for collecting targeted information in situ. Second, despite the complexities underlying travel routines and visit behavior, there exist positive correlations between place preference and automatically detectable features like visit frequency and travel time. And, third, we found that when combined, visit frequency and travel time result in stronger correlations with place rating than when measured individually. Finally, we found no significant difference in place ratings due to the presence of others.

What Is the Range of Surface Reconstructions from a Gradient Field? - Agrawal,Amit; Raskar,Ramesh; Chellapa, Rama (Computer Vision – ECCV 2006Computer Vision – ECCV 2006, 2006)
We propose a generalized equation to represent a continuum of surface reconstruction solutions of a given non-integrable gradient field. We show that common approaches such as Poisson solver and Frankot-Chellappa algorithm are special cases of this generalized equation. For a N × N pixel grid, the subspace of all integrable gradient fields is of dimension N 2 – 1. Our framework can be applied to derive a range of meaningful surface reconstructions from this high dimensional space. The key observation is that the range of solutions is related to the degree of anisotropy in applying weights to the gradients in the integration process. While common approaches use isotropic weights, we show that by using a progression of spatially varying anisotropic weights, we can achieve significant improvement in reconstructions. We propose (a) α-surfaces using binary weights, where the parameter α allows trade off between smoothness and robustness, (b) M-estimators and edge preserving regularization using continuous weights and (c) Diffusion using affine transformation of gradients. We provide results on photometric stereo, compare with previous approaches and show that anisotropic treatment discounts noise while recovering salient features in reconstructions.

3D face modeling from monocular video sequences - Roy-Chowdhury, A.; Chellapa, Rama; Gupta, R. (Face Processing: Advanced Modeling and Methods, 2005)
In this chapter we present two algorithms for 3D face modeling from a monocular video sequence. The firstmethod is based on Structure from Motion (SfM), while the second one relies on contour adaptation over time. The SfM based method incorporates statistical measures of quality of the 3D estimate into the reconstruction algorithm. The initial multi-frame SfM estimate is smoothed using a generic face model in an energy function minimization framework. Such a strategy avoids excessively biasing the final 3D estimate towards the generic model. The second method relies on matching a generic 3D face model to the outer contours of a face in the input video sequence, and integrating this strategy over all the frames in the sequence. It consists of an edge-based head pose estimation step, followed by global and local deformations of the generic face model in order to adapt it to the actual 3D face. This contour adaptation approach is able to separate the geometric subtleties of the human head from the variations in shading and texture, and it does not rely on finding accurate point correspondences across frames. Detailed experimental evaluation of both the methods along with reconstructed 3D models is presented.

3D Facial Pose Tracking in Uncalibrated Videos - Aggarwal,Gaurav; Veeraraghavan,Ashok; Chellapa, Rama (Pattern Recognition and Machine IntelligencePattern Recognition and Machine Intelligence, 2005)
This paper presents a method to recover the 3D configuration of a face in each frame of a video. The 3D configuration consists of the 3 translational parameters and the 3 orientation parameters which correspond to the yaw, pitch and roll of the face, which is important for applications like face modeling, recognition, expression analysis, etc. The approach combines the structural advantages of geometric modeling with the statistical advantages of a particle-filter based inference. The face is modeled as the curved surface of a cylinder which is free to translate and rotate arbitrarily. The geometric modeling takes care of pose and self-occlusion while the statistical modeling handles moderate occlusion and illumination variations. Experimental results on multiple datasets are provided to show the efficacy of the approach. The insensitivity of our approach to calibration parameters (focal length) is also shown.

Adaptively-secure, non-interactive public-key encryption - Canetti,R.; Halevi,S.; Katz, Jonathan (Theory of Cryptography, 2005)
Adaptively-secure encryption schemes ensure secrecy even in the presence of an adversary who can corrupt parties in an adaptive manner based on public keys, ciphertexts, and secret data of already-corrupted parties. Ideally, an adaptively-secure encryption scheme should, like standard public-key encryption, allow arbitrarily-many parties to use a single encryption key to securely encrypt arbitrarily-many messages to a given receiver who maintains only a single short decryption key. However, it is known that these requirements are impossible to achieve: no non-interactive encryption scheme that supports encryption of an unbounded number of messages and uses a single, unchanging decryption key can be adaptively secure. Impossibility holds even if secure data erasure is possible.We show that this limitation can be overcome by updating the decryption key over time and making some mild assumptions about the frequency of communication between parties. Using this approach, we construct adaptively-secure, completely non-interactive encryption schemes supporting secure encryption of arbitrarily-many messages from arbitrarily-many senders. Our schemes additionally provide forward security and security against chosen-ciphertext attacks.

An algebraic approach to surface reconstruction from gradient fields - Agrawal,A.; Chellapa, Rama; Raskar, R. (Computer Vision, 2005. ICCV 2005. Tenth IEEE International Conference on, 2005)
Several important problems in computer vision such as shape from shading (SFS) and photometric stereo (PS) require reconstructing a surface from an estimated gradient field, which is usually non-integrable, i.e. have non-zero curl. We propose a purely algebraic approach to enforce integrability in discrete domain. We first show that enforcing integrability can be formulated as solving a single linear system Ax =b over the image. In general, this system is under-determined. We show conditions under which the system can be solved and a method to get to those conditions based on graph theory. The proposed approach is non-iterative, has the important property of local error confinement and can be applied to several problems. Results on SFS and PS demonstrate the applicability of our method.
Keywords: algebra; algebraic; approach; Computer; confinement; discrete; domain; error; field; from; gradient; graph; image; integrability; linear; local; methods; photometric; reconstruction; shading; SHAPE; stereo; surface; system; theory; vision

An Algebraic Theory Of Boundary Crossing Transitions - Ray,Arnab; Cleaveland, Rance; Skou,Arne (Electronic Notes in Theoretical Computer Science, 2005)
This paper gives a process-algebraic semantics for the hierarchical state machine (HSM) fragment of Statecharts, in which state transitions are permitted to cross state boundaries. Although frowned upon by researchers as promoting unstructured modeling, such transitions are used extensively in practice to model parameterized start states and conditional exit states. The purpose of this work is to develop a compositional semantics for HSMs that may be fit together with compositional semantic accounts for Statecharts without boundary-crossing transitions in order to arrive at a compositional theory for virtually the whole Statecharts language. Our technical development consists of a process algebra for HSMs that is equipped with an operational semantics, an argument that bisimulation is a congruence for the algebra, a syntax-directed translation procedure for HSMs into the process algebra, and an equational axiomatization of the algebra.
Keywords: Compositional Semantics; Formal Methods; Process algebra; Statecharts

Algorithmic and architectural design methodology for particle filters in hardware - Sankaranarayanan,A. C; Chellapa, Rama; Srivastava, A. (Computer Design: VLSI in Computers and Processors, 2005. ICCD 2005. Proceedings. 2005 IEEE International Conference on, 2005)
In this paper, we present algorithmic and architectural methodology for building particle filters in hardware. Particle filtering is a new paradigm for filtering in presence of nonGaussian nonlinear state evolution and observation models. This technique has found wide-spread application in tracking, navigation, detection problems especially in a sensing environment. So far most particle filtering implementations are not lucrative for real time problems due to excessive computational complexity involved. In this paper, we re-derive the particle filtering theory to make it more amenable to simplified VLSI implementations. Furthermore, we present and analyze pipelined architectural methodology for designing these computational blocks. Finally, we present an application using the bearing only tracking problem and evaluate the proposed architecture and algorithmic methodology.
Keywords: (numerical; algorithmic; architectural; architectures; bearing; complexity; computational; design; digital; evolution; Filtering; filtering; filters; implementation; methodology; methods); nonGaussian; nonlinear; only; Parallel; particle; pipeline; pipelined; problem; processing; state; tracking; VLSI; VLSI

Appearance modeling under geometric context - Li,Jian; Zhou,S. K; Chellapa, Rama (Computer Vision, 2005. ICCV 2005. Tenth IEEE International Conference on, 2005)
We propose a unified framework based on a general definition of geometric transform (GeT) for modeling appearance. GeT represents the appearance by applying designed functionals over certain geometric sets. We show that image warping, Radon transform, trace transform, etc. are special cases of our definition. Moreover, three different types of GeTs are designed to handle deformation, articulation and occlusion and applied to fingerprinting the appearance inside a contour. They include the contour-driven GeT, the feature curve based GeT and selecting functionals to model the appearance inside the convex hull of the contour. A multi-resolution representation that combines both shape and appearance information is also proposed. We apply our approach to image synthesis and object recognition. The proposed approach produces promising results when applied to fingerprinting the appearance of human and body parts despite the challenges due to articulated motion and deformations
Keywords: based; curve; geometry; image; GeT; convex; GeT; fingerprinting; geometric; hull; feature; information; trace; modeling; contour-driven; Radon; recognition; recognition; shape; representation; object; synthesis; image; transform; appearance; transform; image; transform; Radon; transforms; computational; warping; multi-resolution

An architectural level design methodology for embedded face detection - Kianzad,V.; Saha,S.; Schlessman,J.; Aggarwal,G.; Bhattacharyya, Shuvra S.; Wolf,W.; Chellapa, Rama (Proceedings of the 3rd IEEE/ACM/IFIP international conference on Hardware/software codesign and system synthesis, 2005)
Face detection and recognition research has attracted great attention in recent years. Automatic face detection has great potential in a large array of application areas, including banking and security system access control, video surveillance, and multimedia information retrieval. In this paper, we discuss an architectural level design methodology for implementation of an embedded face detection system on a reconfigurable system on chip. We present models for performance estimation and validate these models with experimental values obtained from implementing our system on an FPGA platform. This modeling approach is shown to be efficient, accurate, and intuitive for designers to work with. Using this approach, we present several design options that trade-off various architectural features.
Keywords: design space exploration; Face detection; platforms; reconfigurable; system-level models