Are GSM phones THE solution for localization? - Varshavsky,A.; Chen,M.Y.; de Lara,E.; Jon Froehlich; Haehnel,D.; Hightower,J.; LaMarca,A.; Potter,F.; Sohn,T.; Tang,K.; others (Mobile Computing Systems and Applications, 2006. WMCSA'06. Proceedings. 7th IEEE Workshop on, 2005)

Automated checking for Windows host vulnerabilities - Tamizi,M.; Weinstein,M.; Michel Cukier (2005)
Evaluation of computing system security requires knowledge of the vulnerabilities present in the system and of potential attacks against the system. Vulnerabilities can be classified based on their location as application vulnerabilities, network vulnerabilities, or host vulnerabilities. This paper describes Ferret-Windows, a new software tool for checking host vulnerabilities on the Windows platforms. This tool helps system administrators by quickly finding vulnerabilities that are present on a host. It is designed and implemented in a modular way: a plug-in module is used for each vulnerability checked, and each possible output format is specified by a plug-in module. Moreover, several vulnerability fixing plug-in modules exist to help users remove specific vulnerabilities. As a result, Ferret-Windows is extensible, and can easily be kept up-to-date through the addition of checks for new vulnerabilities as they are identified. Finally, Ferret-Windows is a freely available open-source software
Keywords: application vulnerabilities; computing system security; Ferret-Windows software tool; host vulnerabilities; network vulnerabilities; open-source software; operating systems (computers); plug-in module; program diagnostics; security of data; software reliability; software tools; system attacks; Windows host vulnerability checking; Windows platforms

Average relative radiance transform for subpixel detection - Broadwater, J.; Meth, R.; Chellapa, Rama (Geoscience and Remote Sensing Symposium, 2005. IGARSS '05. Proceedings. 2005 IEEE International, 2005)

Background learning for robust face recognition with PCA in the presence of clutter - Rajagopalan, AN; Chellapa, Rama; Koterba, N.T. (Image Processing, IEEE Transactions on, 2005)
We propose a new method within the framework of principal component analysis (PCA) to robustly recognize faces in the presence of clutter. The traditional eigenface recognition (EFR) method, which is based on PCA, works quite well when the input test patterns are faces. However, when confronted with the more general task of recognizing faces appearing against a background, the performance of the EFR method can be quite poor. It may miss faces completely or may wrongly associate many of the background image patterns to faces in the training set. In order to improve performance in the presence of background, we argue in favor of learning the distribution of background patterns and show how this can be done for a given test image. An eigenbackground space is constructed corresponding to the given test image and this space in conjunction with the eigenface space is used to impart robustness. A suitable classifier is derived to distinguish nonface patterns from faces. When tested on images depicting face recognition in real situations against cluttered background, the performance of the proposed method is quite good with fewer false alarms.
Keywords: Automated; Principal Component Analysis; Reproducibility of Results; Sensitivity and Specificity; Signal Processing; Biological; Models; Computer-Assisted; Information Storage and Retrieval; Models; Computer-Assisted; Subtraction Technique; PCA; background learning; clutter; eigenface recognition method; face recognition; linear discriminant; principal component analysis; clutter; eigenvalues and eigenfunctions; face recognition; learning (artificial intelligence); principal component analysis; Algorith; Statistical; Pattern Recognition

Bayesian algorithms for simultaneous structure from motion estimation of multiple independently moving objects - Qian,Gang; Chellapa, Rama; Qinfen Zheng (Image Processing, IEEE Transactions on, 2005)
The problem of simultaneous structure from motion estimation for multiple independently moving objects from a monocular image sequence is addressed. Two Bayesian algorithms are presented for solving this problem using the sequential importance sampling (SIS) technique. The empirical posterior distribution of object motion and feature separation parameters is approximated by weighted samples. The first algorithm addresses the problem when only two moving objects are present. A singular value decomposition (SVD)-based sample clustering algorithm is shown to be capable of separating samples related to different objects. A pair of SIS procedures is used to track the posterior distribution of the motion parameters. In the second algorithm, a balancing step is added into the SIS procedure to preserve samples of low weights so that all objects have enough samples to propagate empirical motion distributions. By using the proposed algorithms, the relative motions of all the moving objects with respect to the camera can be simultaneously estimated. Both algorithms have been tested on synthetic and real- image sequences. Improved results have been achieved.
Keywords: Automated; Reproducibility of Results; Sensitivity and Specificity; Signal Processing; Bayesian algorithm; clustering algorithm; empirical posterior distribution; feature separation parameter; monocular image sequence; motion estimation; multiple independently moving object; object motion; real-image sequence; sequential importance sampling techniqu; Biological; Models; Computer-Assisted; Imaging; Computer-Assisted; Pattern Recognition; Computer-Assisted; Subtraction Technique; Video Recording; Walking; Statistical; Movement; Numerical Analysis; Three-Dimensional; Information Storage and Retrieval; Models

Beyond one still image: Face recognition from multiple still images or a video sequence (Face ProcessingFace Processing, 2005)
While face recognition (FR) from a single still image has been extensively studied over a decade, FR based on a group of still images (also referred to as multiple still images) or a video sequence is an emerging topic. This is mainly evidenced by the growing increase in the literature. For instance, a research initiative called Face Recognition Grand Challenge [1] has been organized. One specific challenge directly addresses the use of multiple still images to improve the recognition accuracy significantly [3]. Recently a workshop jointly held with CVPR 2004 was devoted to face processing in video [2]. It is predictable that, with the ubiquity of video sequences, face recognition based on video sequences will become more and more popular.

Bootstrapping parsers via syntactic projection across parallel texts - Hwa,Rebecca; Resnik, Philip; Weinberg, Amy; Cabezas,Clara; Kolak,Okan (Nat. Lang. Eng., 2005)
Broad coverage, high quality parsers are available for only a handful of languages. A prerequisite for developing broad coverage parsers for more languages is the annotation of text with the desired linguistic representations (also known as “treebanking”). However, syntactic annotation is a labor intensive and time-consuming process, and it is difficult to find linguistically annotated text in sufficient quantities. In this article, we explore using parallel text to help solving the problem of creating syntactic annotation in more languages. The central idea is to annotate the English side of a parallel corpus, project the analysis to the second language, and then train a stochastic analyzer on the resulting noisy annotations. We discuss our background assumptions, describe an initial study on the “projectability” of syntactic relations, and then present two experiments in which stochastic parsers are developed with minimal human intervention via projection from English.

Building a Coherent Data Pipeline in Microarray Data Analyses: Optimization of Signal/Noise Ratios Using an Interactive Visualization Tool and a Novel Noise Filtering Method (2003) - Seo,Jinwook; Bakay,Marina; Chen,Yi-Wen; Hilmer,Sara; Shneiderman, Ben; Hoffman,Eric P (Institute for Systems Research Technical Reports, 2005)
Motivation: Sources of uncontrolled noise strongly influence data analysis in microarray studies, yet signal/noise ratios are rarely considered in microarray data analyses. We hypothesized that different research projects would have different sources and levels of confounding noise, and built an interactive visual analysis tool to test and define parameters in Affymetrix analyses that optimize the ratio of signal (desired biological variable) versus noise (confounding uncontrolled variables). Results: Five probe set algorithms were studied with and without statistical weighting of probe sets using Microarray Suite (MAS) 5.0 probe set detection p values. The signal/noise optimization method was tested in two large novel microarray datasets with different levels of confounding noise; a 105 sample U133A human muscle biopsy data set (11 groups) (extensive noise), and a 40 sample U74A inbred mouse lung data set (8 groups) (little noise). Success was measured using F-measure value of success of unsupervised clustering into appropriate biological groups (signal). We show that both probe set signal algorithm and probe set detection p-value weighting have a strong effect on signal/noise ratios, and that the different methods performed quite differently in the two data sets. Among the signal algorithms tested, dChip difference model with p-value weighting was the most consistent at maximizing the effect of the target biological variables on data interpretation of the two data sets. Availability: The Hierarchical Clustering Explorer 2.0 is [url=http://www.cs.umd.edu/hcil/hce/]available[/url] online and the improved version of the Hierarchical Clustering Explorer 2.0 with p-value weighting and Fmeasure is available upon request to the first author. Murine arrays (40 samples) are publicly available at the [url=http://microarray.cnmcresearch.org/pgadatatable.asp]PEPR resource.[/url] (Chen et al., 2004).
Keywords: Technical Report

The Challenge of Personal Information Management - Dix,A.; Jones,W.; Czerwinski,M.; Teevan,J.; Plaisant, Catherine; Moran,TP (INTERACT'05: Communicating Naturally through Computers (Adjunct Proceedings), 2005)

Child's play: a comparison of desktop and physical interactive environments - Fails,J. A; Druin, Allison; Guha,M.L.; Chipman,G.; Simms,S.; Churaman,W. (Proceedings of the 2005 conference on Interaction design and children, 2005)

Cholera: the killer from the deep - Rita R Colwell (The Biochemist, 2005)
The current international attention to the importance ofcombating infectious diseases can provide the opportunity for a multidisciplinary approach that joins medicine with many other scientific and technological disciplines. Science and technology are major forces that have the potential to balance the world’s inequities. The connection between cholera and the environment provides a paradigm for this perspective.

Combining self-reported and automatic data to improve programming effort measurement - Hochstein, Lorin; Basili, Victor R.; Zelkowitz, Marvin V; Hollingsworth, Jeffrey K; Carver, Jeff (Proceedings of the 10th European software engineering conference held jointly with 13th ACM SIGSOFT international symposium on Foundations of software engineering, 2005)
Measuring effort accurately and consistently across subjects in a programming experiment can be a surprisingly difficult task. In particular, measures based on self-reported data may differ significantly from measures based on data which is recorded automatically from a subject's computing environment. Since self-reports can be unreliable, and not all activities can be captured automatically, a complete measure of programming effort should incorporate both classes of data. In this paper, we show how self-reported and automatic effort can be combined to perform validation and to measure total programming effort.
Keywords: effort; experimentation; human factors; manual approaches; measurement; process metrics; verification

Comparative Genomics of Trypanosomatid Parasitic Protozoa - El‐Sayed, Najib M.; Myler,Peter J.; Blandin,Gaëlle; Berriman,Matthew; Crabtree,Jonathan; Aggarwal,Gautam; Caler,Elisabet; Renauld,Hubert; Worthey,Elizabeth A.; Hertz-Fowler,Christiane; Ghedin,Elodie; Peacock,Christopher; et al. (Science, 2005)
A comparison of gene content and genome architecture of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major, three related pathogens with different life cycles and disease pathology, revealed a conserved core proteome of about 6200 genes in large syntenic polycistronic gene clusters. Many species-specific genes, especially large surface antigen families, occur at nonsyntenic chromosome-internal and subtelomeric regions. Retroelements, structural RNAs, and gene family expansion are often associated with syntenic discontinuities that—along with gene divergence, acquisition and loss, and rearrangement within the syntenic regions—have shaped the genomes of each parasite. Contrary to recent reports, our analyses reveal no evidence that these species are descended from an ancestor that contained a photosynthetic endosymbiont.

A Comparison of Voice Controlled and Mouse Controlled Web Browsing (2000) - Christian,Kevin; Kules,Bill; Shneiderman, Ben; Youssef,Adel (Institute for Systems Research Technical Reports, 2005)
Voice controlled web browsers allow users to navigate by speaking the text of a link or an associated number instead of clicking with a mouse. One such browser is Conversa, by Conversational Computing. This within subjects study with 18 subjects compared voice browsing with traditional mouse-based browsing. It attempted to identify which of three common hypertext forms (linear slide show, grid/tiled map, and hierarchical menu) are well suited to voice navigation, and whether voice navigation is helped by numbering links. The study shows that voice control adds approximately 50 percent to the performance time for certain types of tasks. Subjective satisfaction measures indicate that for voice browsing, textual links are preferable to numbered links.
Keywords: Technical Report

Computer vision on FPGAs: Design methodology and its application to gesture recognition - Sen,M.; Corretjer,I.; Haim,F.; Saha,S.; Bhattacharyya, Shuvra S.; Schlessman,J.; Wolf,W. (Computer Vision and Pattern Recognition-Workshops, 2005. CVPR Workshops. IEEE Computer Society Conference on, 2005)

Critical Factors Influencing the Occurrence of Vibrio Cholerae in the Environment of Bangladesh - Huq,Anwar; Sack,R. Bradley; Nizam,Azhar; Longini,Ira M.; Nair,G. Balakrish; Ali,Afsar; Morris,J. Glenn; Khan,M. N. Huda; Siddique,A. Kasem; Yunus,Mohammed; Albert,M. John; Sack,David A.; et al. (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2005)
The occurrence of outbreaks of cholera in Africa in 1970 and in Latin America in 1991, mainly in coastal communities, and the appearance of the new serotype Vibrio cholerae O139 in India and subsequently in Bangladesh have stimulated efforts to understand environmental factors influencing the growth and geographic distribution of epidemic Vibrio cholerae serotypes. Because of the severity of recent epidemics, cholera is now being considered by some infectious disease investigators as a “reemerging” disease, prompting new work on the ecology of vibrios. Epidemiological and ecological surveillance for cholera has been under way in four rural, geographically separated locations in Bangladesh for the past 4 years, during which both clinical and environmental samples were collected at biweekly intervals. The clinical epidemiology portion of the research has been published (Sack et al., J. Infect. Dis. 187:96-101, 2003). The results of environmental sampling and analysis of the environmental and clinical data have revealed significant correlations of water temperature, water depth, rainfall, conductivity, and copepod counts with the occurrence of cholera toxin-producing bacteria (presumably V. cholerae). The lag periods between increases or decreases in units of factors, such as temperature and salinity, and occurrence of cholera correlate with biological parameters, e.g., plankton population blooms. The new information on the ecology of V. cholerae is proving useful in developing environmental models for the prediction of cholera epidemics.

Data sharing in ecology and evolution - Parr,Cynthia S.; Cummings, Michael P. (Trends in Ecology & Evolution, 2005)

Design and implementation of a routing control platform - Caesar,Matthew; Caldwell,Donald; Feamster, Nick; Rexford,Jennifer; Shaikh,Aman; van der Merwe,Jacobus (Proceedings of the 2nd conference on Symposium on Networked Systems Design & Implementation - Volume 2, 2005)
The routers in an Autonomous System (AS) must distribute the information they learn about how to reach external destinations. Unfortunately, today's internal Border Gateway Protocol (iBGP) architectures have serious problems: a "full mesh" iBGP configuration does not scale to large networks and "route reflection" can introduce problems such as protocol oscillations and persistent loops. Instead, we argue that a Routing Control Platform (RCP) should collect information about external destinations and internal topology and select the BGP routes for each router in an AS. RCP is a logically-centralized platform, separate from the IP forwarding plane, that performs route selection on behalf of routers and communicates selected routes to the routers using the unmodified iBGP protocol. RCP provides scalability without sacrificing correctness. In this paper, we present the design and implementation of an RCP prototype on commodity hardware. Using traces of BGP and internal routing data from a Tier-1 backbone, we demonstrate that RCP is fast and reliable enough to drive the BGP routing decisions for a large network. We show that RCP assigns routes correctly, even when the functionality is replicated and distributed, and that networks using RCP can expect comparable convergence delays to those using today's iBGP architectures.

Detecting Independent 3D Movement - Corrochano,Eduardo Bayro; Ogale, Abhijit S.; Fermüller, Cornelia; Aloimonos, J. (Handbook of Geometric ComputingHandbook of Geometric Computing, 2005)

Determining Causes and Severity of End-User Frustration (2002) - Ceaparu,Irina; Lazar,Jonathan; Bessiere,Katie; Robinson,John; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
While computers are beneficial to individuals and society, frequently, users encounter frustrating experiences when using computers. This study attempts to measure, through 111 participants, the frequency, cause, and the level of severity of frustrating experiences. The data showed that frustrating experiences happen on a frequent basis. The applications in which the frustrating experiences happened most frequently were web browsing, e-mail, and word processing. The most-cited causes of frustrating experiences were error messages, dropped network connections, long download times, and hard-to-find features. The time lost due to frustrating experiences ranged from 47-53% of time spent on a computer depending on the location and study method. After discarding extreme cases the time lost was still above 38%. These disturbing results should be a basis for future study.
Keywords: Technical Report

DOCLIB: A document processing research tool - Chen,Kevin; Jaeger,Stefan; Zhu,Guangyu; David Doermann (Symposium on Document Image Understanding Technology, 2005)
Often, valuable document processing intellectual capital is lost due to staff transitions or project restructuring prior to technology transfer. Furthermore, hardware and software integrity, dependencies, and compatibility are critical components that often impede technology migration. While many open source tools attempt to mitigate these issues, they do not always address specific design needs and tailored-process that Government organizations must adhere to. This paper addresses the need for a common document processing research vehicle through which institutions can develop and share research-related software and applications across academic, business, and Government domains.

Efficient temporal-logic query checking for presburger systems - Zhang,Dezhuang; Cleaveland, Rance (Proceedings of the 20th IEEE/ACM international Conference on Automated software engineering, 2005)
This paper develops a framework for solving temporal-logic query-checking problems for a class of infinite-state system models that compute with integer-valued variables (so-called Presburger systems, in which Presburger formulas are used to define system behavior). The temporal-logic query checking problem may be formulated as follows: given a model and a temporal logic formula with placeholders, compute a set of assignments of formulas to placeholders such that the resulting temporal formula is satisfied by the given model. Temporal-logic query checking has proved useful as a means for requirements and design understanding; existing work, however, has focused only on propositional temporal logic and finite-state systems.Our method is based on a symbolic model-checking technique that relies on proof search. The paper first introduces this model-checking approach and then shows how it can be adapted to solving the temporal queries in which formulas may contain integer variables. We also present experimental results showing the computational efficacy of our approach.
Keywords: Formal Methods; Model checking; on-the-fly symbolic model checking; Presburger systems; query checking

Ego-Motion Estimation and 3D Model Refinement in Scenes with Varying Illumination - Agrawal,Amit K; Chellapa, Rama (Application of Computer Vision, 2005. WACV/MOTIONS '05 Volume 1. Seventh IEEE Workshops on, 2005)
We present an iterative algorithm for robustly estimating the ego-motion and refining and updating a coarse depth map using surface parallax and a generalized dynamic image (GDI) model. Given a coarse depth map acquired by a range-finder or extracted from a Digital Elevation Map (DEM), we first estimate the ego-motion by combining a global ego-motion constraint and a local GDI model. Using the estimated camera motion and the available depth estimate, motion of the 3D points is compensated. We utilize the fact that the resulting surface parallax field is an epipolar field and constrain its direction using the previous motion estimates. We then estimate the magnitude of the parallax field and the GDI model parameters locally and use them to refine the depth map estimates. We use a tensor based approach to formulate the depth refinement procedure as an eigen-value problem and obtain confidence measures for determining the accuracy of the estimated depth values. These confidence measures are used to remove regions with potentially incorrect depth estimates for robustly estimating ego-motion in the next iteration. Experimental results using both synthetic and real data are presented. Comparisons with results obtained using a brightness constancy (BC) model show that the proposed algorithm works significantly better when time-varying illumination changes are present in the scene.

Evaluation Methodologies for Visual Analytics - Laskowski,S.; Plaisant, Catherine (Illuminating the Path: The Research and Development Agenda for Visual AnalyticsIlluminating the Path: The Research and Development Agenda for Visual Analytics, 2005)
Keywords: file-import-09-03-18

An evolutionary testbed for software technology evaluation - Lindvall,M.; Rus,I.; Shull, F.; Zelkowitz, Marvin V; Donzelli,P.; Memon, Atif M.; Basili, Victor R.; Costa,P.; Tvedt,R.; Hochstein, L. (Innovations in Systems and Software Engineering, 2005)
Empirical evidence and technology evaluation are needed to close the gap between the state of the art and the state of the practice in software engineering. However, there are difficulties associated with evaluating technologies based on empirical evidence: insufficient specification of context variables, cost of experimentation, and risks associated with trying out new technologies. In this paper, we propose the idea of an evolutionary testbed for addressing these problems. We demonstrate the utility of the testbed in empirical studies involving two different research technologies applied to the testbed, as well as the results of these studies. The work is part of NASArsquos High Dependability Computing Project (HDCP), in which we are evaluating a wide range of new technologies for improving the dependability of NASA mission-critical systems.

Executable requirements specifications using triggered message sequence charts - Sengupta,B.; Cleaveland, Rance (Distributed Computing and Internet Technology, 2005)

An experimental evaluation to determine if port scans are precursors to an attack - Panjwani,S.; Tan,S.; Jarrin,K.M.; Michel Cukier (2005)
This paper describes an experimental approach to determine the correlation between port scans and attacks. Discussions in the security community often state that port scans should be considered as precursors to an attack. However, very few studies have been conducted to quantify the validity of this hypothesis. In this paper, attack data were collected using a test-bed dedicated to monitoring attackers. The data collected consist of port scans, ICMP scans, vulnerability scans, successful attacks and management traffic. Two experiments were performed to validate the hypothesis of linking port scans and vulnerability scans to the number of packets observed per connection. Customized scripts were then developed to filter the collected data and group them on the basis of scans and attacks between a source and destination IP address pair. The correlation of the filtered data groups was assessed. The analyzed data consists of forty-eight days of data collection for two target computers on a heavily utilized subnet.
Keywords: attack data collection; computer crime; filtered data groups; ICMP scans; IP address; IP networks; management traffic; port scans; telecommunication security; Telecommunication traffic; vulnerability scans

Extending the Utility of Treemaps with Flexible Hierarchy (2004) - Chintalapani,Gouthami; Plaisant, Catherine; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
Treemaps is a visualization technique for presenting hierarchical information on two dimensional displays. Prior implementations limit the visualization to pre-defined static hierarchies. Flexible hierarchy, a new capability of Treemap 4.0, enables users to define various hierarchies through dynamically selecting a series of data attributes so that they can discover patterns, clusters and outliers. This paper describes the design and implementation issues of flexible hierarchy. It then reports on a usability study which led to enhancements to the interface.
Keywords: Technical Report

Face recognition in the presence of multiple illumination sources - Aggarwal,G.; Chellapa, Rama (Computer Vision, 2005. ICCV 2005. Tenth IEEE International Conference on, 2005)
Most existing face recognition algorithms work well for controlled images but are quite susceptible to changes in illumination and pose. This has led to the rise of analysis-by-synthesis approaches due to their inherent potential to handle these external factors. Though these approaches work quite well, most of them assume that the face is illuminated by a single light source which is usually not true in realistic conditions. In this paper, we propose an algorithm to recognize faces illuminated by arbitrarily placed, multiple light sources. The algorithm does not need to know the number of light sources and works extremely well even while recognizing faces illuminated by different number of light sources. Results using this algorithm are reported on multiple-illumination datasets generated from PIE by T. Sim, et al. (2003) and Yale Face Database B by W. Zhao, et al. (2003). We also highlight the importance of the hard non-linearity in the Lambert's law which is often ignored, probably to linearize the estimation process
Keywords: approach; estimation; illumination; Lambert; law; analysis-by-synthesis; nonlinearity; multiple; process; face; recognition; hard; recognition; light; source; face; sources

A Factorization Method for Structure from Planar Motion - Li,Jian; Chellapa, Rama (Application of Computer Vision, 2005. WACV/MOTIONS '05 Volume 1. Seventh IEEE Workshops on, 2005)
We propose a factorization method for structure from planar motion using a stationary perspective camera. Compared with [A factorization based algorithm for multi-image projective structure and motion] for general motion, our work has three major differences: a different measurement matrix specialized for planar motion is formed. The measurement matrix has a rank of at most 3, instead of 4; the measurement matrix needs similar scalings, but estimation of fundamental matrices or epipoles is not needed; we have an Euclidean reconstruction instead of a projective reconstruction. The camera is not required to be calibrated. A simple semi-automatic calibration method using vanishing points and lines is sufficient. Experimental results show that the algorithm is accurate and fairly robust to noise and inaccurate calibration.

Fast generic model-checking for data-based systems - Zhang,D.; Cleaveland, Rance (Formal Techniques for Networked and Distributed Systems-FORTE 2005, 2005)

Fast on-the-fly parametric real-time model checking - Zhang,D.; Cleaveland, Rance (Real-Time Systems Symposium, 2005. RTSS 2005. 26th IEEE International, 2005)

Finding Governmental Statistical Data on the Web: Three Empirical Studies of the FedStats Topics Page (2003) - Ceaparu,Irina; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
Keywords: Technical Report

A framework for set-oriented computation in inductive logic programming and its application in generalizing inverse entailment - Corrada Bravo, Hector; Page,D.; Ramakrishnan,R.; Shavlik,J.; Costa,V. S (Inductive Logic Programming, 2005)

Fusing Depth and Video Using Rao-Blackwellized Particle Filter - Agrawal,Amit; Chellapa, Rama (Pattern Recognition and Machine IntelligencePattern Recognition and Machine Intelligence, 2005)
We address the problem of fusing sparse and noisy depth data obtained from a range finder with features obtained from intensity images to estimate ego-motion and refine 3D structure of a scene using a Rao-Blackwellized particle filter. For scenes with low depth variability, the algorithm shows an alternate way of performing Structure from Motion (SfM) starting with a flat depth map. Instead of using 3D depths, we formulate the problem using 2D image domain parallax and show that conditioned on non-linear motion parameters, the parallax magnitude with respect to the projection of the vanishing point forms a linear subsystem independent of camera motion and their distributions can be analytically integrated. Thus, the structure is obtained by estimating parallax with respect to the given depths using a Kalman filter and only the ego-motion is estimated using a particle filter. Hence, the required number of particles becomes independent of the number of feature points which is an improvement over previous algorithms. Experimental results on both synthetic and real data show the effectiveness of our approach.

Gait-based human identification using appearance matching - Kale, A.; Cuntoor, N.; Yegnanarayana,B.; Rajagopalan, A.; Chellapa, Rama (Optical and Digital Techniques for Information Security, 2005)
In this chapter, we present an appearance-based approach for recognizing human gait. Given the gait video of an individual, the images are binarized and the width of the outer contour of the silhouette of that individual is obtained for each image frame. Several gait features are derived from this basic width vector. Temporally ordered sequences of the feature vectors are then used to represent the gait of a person. While matching the feature templates for recognition, dynamic time-warping (DTW), which is a nonlinear time-normalization technique, is used to deal with naturally occurring changes in the walking speeds of individuals. The performance of the proposed method is tested on indoor as well as outdoor gait databases, and the efficacy of different gait features and their noise resilience is studied. The experiments also demonstrate the effect of change in the viewing angle and frame rate of data capture on the accuracy of gait recognition.

Generating testable hypotheses from tacit knowledge for high productivity computing - Asgari, Sima; Hochstein, Lorin; Basili, Victor R.; Zelkowitz, Marvin V; Hollingsworth, Jeffrey K; Carver, Jeff; Shull, Forrest (Proceedings of the second international workshop on Software engineering for high performance computing system applications, 2005)
In this research, we are developing our understanding of how the high performance computing community develops effective parallel implementations of programs by collecting the folklore within the community. We use this folklore as the basis for a series of experiments, which we expect, will validate or negate these assumptions.
Keywords: folklore elicitation; high productivity development time experimental studies; hypothesis generation; tacit knowledge solicitation; testable hypotheses

The genome of the African trypanosome Trypanosoma brucei - Berriman,M.; Ghedin,E.; Hertz-Fowler,C.; Blandin,G.; Renauld,H.; Bartholomeu,D. C; Lennard,N. J; Caler,E.; Hamlin,N. E; Haas,B.; others (Science, 2005)

The Genome Sequence of Trypanosoma cruzi, Etiologic Agent of Chagas Disease - El‐Sayed, Najib M.; Myler,Peter J.; Bartholomeu,Daniella C.; Nilsson,Daniel; Aggarwal,Gautam; Tran,Anh-Nhi; Ghedin,Elodie; Worthey,Elizabeth A.; Delcher,Arthur L.; Blandin,Gaëlle; Westenberger,Scott J.; Caler,Elisabet; et al. (Science, 2005)
Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.

The Genome Sequence of Trypanosoma Cruzi, Etiologic Agent of Chagas Disease - El‐Sayed, Najib M.; Myler,Peter J.; Bartholomeu,Daniella C.; Nilsson,Daniel; Aggarwal,Gautam; Tran,Anh-Nhi; Ghedin,Elodie; Worthey,Elizabeth A.; Delcher,Arthur L.; Blandin,Gaëlle; Westenberger,Scott J.; Caler,Elisabet; et al. (ScienceScience, 2005)
Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.

Genome-Wide Analysis of Chromosomal Features Repressing Human Immunodeficiency Virus Transcription - Lewinski,M. K; Bisgrove,D.; Shinn,P.; Chen,H.; Hoffmann,C.; Hannenhalli, Sridhar; Verdin,E.; Berry,C. C; Ecker,J. R; Bushman,F. D (Journal of VirologyJ. Virol., 2005)
We have investigated regulatory sequences in noncoding human DNA that are associated with repression of an integrated human immunodeficiency virus type 1 (HIV-1) promoter. HIV-1 integration results in the formation of precise and homogeneous junctions between viral and host DNA, but integration takes place at many locations. Thus, the variation in HIV-1 gene expression at different integration sites reports the activity of regulatory sequences at nearby chromosomal positions. Negative regulation of HIV transcription is of particular interest because of its association with maintaining HIV in a latent state in cells from infected patients. To identify chromosomal regulators of HIV transcription, we infected Jurkat T cells with an HIV-based vector transducing green fluorescent protein (GFP) and separated cells into populations containing well-expressed (GFP-positive) or poorly expressed (GFP-negative) proviruses. We then determined the chromosomal locations of the two classes by sequencing 971 junctions between viral and cellular DNA. Possible effects of endogenous cellular transcription were characterized by transcriptional profiling. Low-level GFP expression correlated with integration in (i) gene deserts, (ii) centromeric heterochromatin, and (iii) very highly expressed cellular genes. These data provide a genome-wide picture of chromosomal features that repress transcription and suggest models for transcriptional latency in cells from HIV-infected patients.

Genome-wide analysis of retroviral DNA integration - Bushman,Frederic; Lewinski,Mary; Ciuffi,Angela; Barr,Stephen; Leipzig,Jeremy; Hannenhalli, Sridhar; Hoffmann,Christian (Nat Rev MicroNat Rev Micro, 2005)

Global microbial ecology of Vibrio cholerae - Rita R Colwell (Oceans and health: pathogens in the marine environment, 2005)
The disease cholera can no longer be considered a simple equation of bacteria and human host, but represents a complex network that includes global weather patterns, aquatic reservoirs, phages, zooplankton, collective behavior of surface-attached cells, an adaptable genome, and the deep sea inter alia. This interesting characterization emerges from a view of biological systems termed biocomplexity (Colwell, 2002a, b). The holistic approach to understanding cholera integrates contributions from experts in many fields, with multiple points of view, in models for prediction, prevention, and treatment of the disease that Vibrio cholerae causes. The spiral form shown in Figure 12.1 symbolizes the nonlinear manner in which the many parts of such a model interact. It also shows that these interactions often occur across many different scales.

Grid computing - Cummings, Michael P.; Huskamp,J. C (EDUCAUSE Review, 2005)

Help! I'm Lost: User Frustration in Web Navigation (2003) - Lazar,Jonathan; Bessiere,Katie; Ceaparu,Irina; Robinson,John; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
Computers can be valuable tools, and networked resources via the Internet can be beneficial to many different populations and communities. Unfortunately, when people are unable to reach their task goals due to frustrating experiences, this can hinder the effectiveness of technology. This research summary provides information about the user frustration research that has been performed at the University of Maryland and Towson University. Causes of user frustration are discussed in this research summary, along with the surprising finding that nearly one-third to one-half of the time spent in front of the computer is wasted due to frustrating experiences. Furthermore, when interfaces are planned to be deceptive and confusing, this
Keywords: Technical Report

The Hiero machine translation system: Extensions, evaluation, and analysis - Chiang,D.; Lopez,A.; Madnani,N.; Monz,C.; Resnik, Philip; Subotin,M. (Proceedings of the conference on Human Language Technology and Empirical Methods in Natural Language Processing, 2005)

Human action-recognition using mutual invariants - Parameswaran,Vasu; Chellapa, Rama (Computer Vision and Image Understanding, 2005)
Static and temporally varying 3D invariants are proposed for capturing the spatio-temporal dynamics of a general human action to enable its representation in a compact, view-invariant manner. Two variants of the representation are presented and studied: (1) a restricted-3D version, whose theory and implementation are simple and efficient but which can be applied only to a restricted class of human action, and (2) a full-3D version, whose theory and implementation are more complex but which can be applied to any general human action. A detailed analysis of the two representations is presented. We show why a straightforward implementation of the key ideas does not work well in the general case, and present strategies designed to overcome inherent weaknesses in the approach. What results is an approach for human action modeling and recognition that is not only invariant to viewpoint, but is also robust enough to handle different people, different speeds of action (and hence, frame rate) and minor variabilities in a given action, while encoding sufficient distinction among actions. Results on 2D projections of human motion capture and on manually segmented real image sequences demonstrate the effectiveness of the approach.
Keywords: Human action-recognition; Model based invariants; Mutual invariants; View invariance

Image Sequence Stabilization, Mosaicking, and Superresolution - Chellapa, Rama; Srinivasan, S.; Aggarwal,G.; Veeraraghavan,A. (Handbook of Image and Video Processing (Second Edition)Handbook of Image and Video Processing (Second Edition), 2005)
A sequence of temporal images gathered from a single sensor adds a whole new dimension to two-dimensional (2D) image data. Availability of an image sequence permits the measurement of quantities such as subpixel intensities, camera motion and depth, and detection and tracking of moving objects. In turn, the processing of image sequences necessitates the development of sophisticated techniques to extract this information. With the recent availability of powerful yet inexpensive computers, data storage systems, and image acquisition devices, image sequence analysis has transitioned from an esoteric research domain to a practical area with significant commercial interest.

Image-based face recognition under illumination and pose variations - Zhou,Shaohua Kevin; Chellapa, Rama (Journal of the Optical Society of America AJ. Opt. Soc. Am. A, 2005)
We present an image-based method for face recognition across different illuminations and poses, where the term image-based means that no explicit prior three-dimensional models are needed. As face recognition under illumination and pose variations involves three factors, namely, identity, illumination, and pose, generalizations in all these three factors are desired. We present a recognition approach that is able to generalize in the identity and illumination dimensions and handle a given set of poses. Specifically, the proposed approach derives an identity signature that is illumination- and pose-invariant, where the identity is tackled by means of subspace encoding, the illumination is characterized with a Lambertian reflectance model, and the given set of poses is treated as a whole. Experimental results using the Pose, Illumination, and Expression (PIE) database demonstrate the effectiveness of the proposed approach.
Keywords: illumination; pattern recognition

Improved approximation bounds for planar point pattern matching - Cho,M.; Mount, Dave (Algorithms and Data Structures, 2005)
We consider the well known problem of matching two planar point sets under rigid transformations so as to minimize the directed Hausdorff distance. This is a well studied problem in computational geometry. Goodrich, Mitchell, and Orletsky [GMO94] presented a very simple approximation algorithm for this problem, which computes transformations based on aligning pairs of points. They showed that their algorithm achieves an approximation ratio of 4. We consider a minor modification to their algorithm, which is based on aligning midpoints rather than endpoints. We show that this algorithm achieves an approximation ratio not greater than 3.13. Our analysis is sensitive to the ratio between the diameter of the pattern set and the Hausdorff distance, and we show that the approximation ratio approaches 3 in the limit. Finally, we provide lower bounds that show that our approximation bounds are nearly tight.

Improving Web-based Civic Information Access: A Case Study of the 50 US States (2002) - Ceaparu,Irina; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
An analysis of the home pages of all fifty U. S. states reveals great variety in key design features that influence efficacy. Some states had excessively large byte counts that would slow users connected by commonly-used 56K modems. Many web sites had low numbers of or poorly organized links that would make it hard for citizens to find what they were interested in. Features such as search boxes, privacy policies, online help, or contact information need to be added by several states. Our analysis concludes with ten recommendations and finds many further opportunities for individual states to improve their websites. However still greater benefits will come through collaboration among the states that would lead to consistency, appropriate tagging, and common tools.
Keywords: Technical Report

An integrated framework for scenarios and state machines - Sengupta,B.; Cleaveland, Rance (Integrated Formal Methods, 2005)

Interactive Color Mosaic and Dendogram Displays for Signal/Noise Optimization in Microarray Data Analysis (2003) - Seo,Jinwook; Bakay,Marina; Zhao,Po; Chen,Yi-Wen; Clarkson,Priscilla; Shneiderman, Ben; Hoffman,Eric P (Institute for Systems Research Technical Reports, 2005)
Data analysis and visualization is strongly influenced by noise and noise filters. There are multiple sources of oisein microarray data analysis, but signal/noise ratios are rarely optimized, or even considered. Here, we report a noise analysis of a novel 13 million oligonucleotide dataset - 25 human U133A (~500,000 features) profiles of patient muscle biposies. We use our recently described interactive visualization tool, the Hierarchical Clustering Explorer (HCE) to systemically address the effect of different noise filters on resolution of arrays into orrectbiological groups (unsupervised clustering into three patient groups of known diagnosis). We varied probe set interpretation methods (MAS 5.0, RMA), resent callfilters, and clustering linkage methods, and investigated the results in HCE. HCE interactive features enabled us to quickly see the impact of these three variables. Dendrogram displays showed the clustering results systematically, and color mosaic displays provided a visual support for the results. We show that each of these three variables has a strong effect on unsupervised clustering. For this dataset, the strength of the biological variable was maximized, and noise minimized, using MAS 5.0, 10% present call filter, and Average Group Linkage. We propose a general method of using interactive tools to identify the optimal signal/noise balance or the optimal combination of these three variables to maximize the effect of the desired biological variable on data interpretation.
Keywords: Technical Report

Interpretation of state sequences in HMM for activity representation - Cuntoor, N.P.; Yegnanarayana,B.; Chellapa, Rama (Proc. IEEE Conf. Acoustic Speech and Signal Processing, 2005)
We propose a method for activity representation based on seman-tic events, using the HMM framework. For every time instant, the probability of event occurrence is computed by exploring a subset of state sequences. The idea is that while activity trajectories may have large variations at the data or the state levels, they may ex- hibit similarities at the event level. Our experiments show the ap- plication of these events to activity recognition in an office envi- ronment and to anomalous trajectory detection using surveillance video data.

Kernel-based Bayesian filtering for object tracking - Han,Bohyung; Zhu,Ying; Comaniciu, D.; Davis, Larry S. (Computer Vision and Pattern Recognition, 2005. CVPR 2005. IEEE Computer Society Conference on, 2005)
Particle filtering provides a general framework for propagating probability density functions in nonlinear and non-Gaussian systems. However, the algorithm is based on a Monte Carlo approach and sampling is a problematic issue, especially for high dimensional problems. This paper presents a new kernel-based Bayesian filtering framework, which adopts an analytic approach to better approximate and propagate density functions. In this framework, the techniques of density interpolation and density approximation are introduced to represent the likelihood and the posterior densities by Gaussian mixtures, where all parameters such as the number of mixands, their weight, mean, and covariance are automatically determined. The proposed analytic approach is shown to perform sampling more efficiently in high dimensional space. We apply our algorithm to real-time tracking problems, and demonstrate its performance on real video sequences as well as synthetic examples.
Keywords: approach; approximation; Bayes; Bayesian; Carlo; density; detection; filtering; functions; Gaussian; interpolation; kernel-based; methods; mixtures; Monte; nonGaussian; nonlinear; object; particle; probability; probability; processes; recognition; sampling; sampling; sequences; system; tracking; video

Magic bullets and golden rules: data sampling in molecular phylogenetics - Cummings, Michael P.; Meyer,A. (Zoology (Jena), 2005)
Data collection for molecular phylogenetic studies is based on samples of both genes and taxa. In an ideal world, with no limitations to resources, as many genes could be sampled as deemed necessary to address phylogenetic problems. Given limited resources in the real world, inadequate (in terms of choice of genes or number of genes) sequences or restricted taxon sampling can adversely affect the reliability or information gained in phylogenetics. Recent empirical and simulation-based studies of data sampling in molecular phylogenetics have reached differing conclusions on how to deal with these problems. Some advocated sampling more genes, others more taxa. There is certainly no 'magic bullet' that will fit all phylogenetic problems, and no specific 'golden rules' have been deduced, other than that single genes may not always contain sufficient phylogenetic information. However, several general conclusions and suggestions can be made. One suggestion is that the determination of a multiple, but moderate number (e.g., 6-10) of gene sequences might take precedence over sequencing a larger set of genes and thereby permit the sampling of more taxa for a phylogenetic study.

Markerless Motion Capture using Multiple Cameras - Sundaresan, A.; Chellapa, Rama (Computer Vision for Interactive and Intelligent Environment, 2005, 2005)
Motion capture has important applications in different areas such as biomechanics, computer animation, and human-computer interaction. Current motion capture methods use passive markers that are attached to different body parts of the subject and are therefore intrusive in nature. In applications such as pathological human movement analysis, these markers may introduce an unknown artifact in the motion, and are, in general, cumbersome. We present computer vision based methods for performing markerless human motion capture. We model the human body as a set of super-quadrics connected in an articulated structure and propose algorithms to estimate the parameters of the model from video sequences. We compute a volume data (voxel) representation from the images and combine bottom-up approach with top down approach guided by our knowledge of the model. We propose a tracking algorithm that uses this model to track human pose. The tracker uses an iterative framework akin to an Iterated Extended Kalman Filter to estimate articulated human motion using multiple cues that combine both spatial and temporal information in a novel manner. We provide preliminary results using data collected from 8-16 cameras. The emphasis of our work is on models and algorithms that are able to scale with respect to the requirement for accuracy. Our ultimate objective is to build an end-to-end system that can integrate the above mentioned components into a completely automated markerless motion capture system.

Matching shape sequences in video with applications in human movement analysis - A,Veeraraghavan; Roy-Chowdhury, A.K.; Chellapa, Rama (Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2005)
We present an approach for comparing two sequences of deforming shapes using both parametric models and nonparametric methods. In our approach, Kendall's definition of shape is used for feature extraction. Since the shape feature rests on a non-Euclidean manifold, we propose parametric models like the autoregressive model and autoregressive moving average model on the tangent space and demonstrate the ability of these models to capture the nature of shape deformations using experiments on gait-based human recognition. The nonparametric model is based on dynamic time-warping. We suggest a modification of the dynamic time-warping algorithm to include the nature of the non-Euclidean space in which the shape deformations take place. We also show the efficacy of this algorithm by its application to gait-based human recognition. We exploit the shape deformations of a person's silhouette as a discriminating feature and provide recognition results using the nonparametric model. Our analysis leads to some interesting observations on the role of shape and kinematics in automated gait-based person authentication.
Keywords: Automated; Photography; Reproducibility of Results; Sensitivity and Specificity; Subtraction Technique; Video Recording; autoregressive moving average model; deforming shapes; dynamic time-warping; feature extraction; gait-based human recognition; human movement analysis; matching shape sequences; video; autoregressive moving average processes; feature extraction; image matching; imag; Biological; Models; Computer-Assisted; Imaging; Statistical; Movement; Pattern Recognition; Three-Dimensional; Leg; Models

A method for converting a smiling face to a neutral face with applications to face recognition - Ramachandran, M.; Zhou,S. K; Jhalani, D.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2005. Proceedings. (ICASSP '05). IEEE International Conference on, 2005)
The human face displays a variety of expressions, like smile, sorrow, surprise, etc. All these expressions constitute nonrigid motions of various features of the face. These expressions lead to a significant change in the appearance of a facial image which leads to a drop in the recognition accuracy of a face-recognition system trained with neutral faces. There are other factors like pose and illumination which also lead to performance drops. Researchers have proposed methods to tackle the effects of pose and illumination; however, there has been little work on how to tackle expressions. We attempt to address the issue of expression invariant face-recognition. We present preprocessing steps for converting a smiling face to a neutral face. We expect that this would in turn make the vector in the feature space to be closer to the correct vector in the gallery, in an appearance-based face recognition. This conjecture is supported by our recognition results which demonstrate that the accuracy goes up if we include the expression-normalization block.
Keywords: appearance-based; Expression; Face; face; feature; invariant; motion; neutral; nonrigid; normalization; recognition; smiling

Mitigating risk of data loss in preservation environments - Moore,R.W.; JaJa, Joseph F.; Chadduck,R. (Mass Storage Systems and Technologies, 2005. Proceedings. 22nd IEEE / 13th NASA Goddard Conference on, 2005)
Preservation environments manage digital records for time periods that are much longer than that of a single vendor product. A primary requirement is the preservation of the authenticity and integrity of the digital records while simultaneously minimizing the cost of long-term storage, as the data is migrated onto successive generations of technology. The emergence of low-cost storage hardware has made it possible to implement innovative software systems that minimize risk of data loss and preserve authenticity and integrity. This paper describes software mechanisms in use in current persistent archives and presents an example based upon the NARA research prototype persistent archive.
Keywords: archives; authentication; authenticity; computing; data; databases; digital; distributed; environment; Grid; integrity; management; message; objects; persistent; preservation; record; risk; storage

Morse-Smale decompositions for modeling terrain knowledge - Čomić,L.; De Floriani, Leila; Papaleo,L. (Spatial Information Theory, 2005)
In this paper, we describe, analyze and compare techniques for extracting spatial knowledge from a terrain model. Specifically, we investigate techniques for extracting a morphological representation from a terrain model based on an approximation of a Morse-Smale complex. A Morse-Smale complex defines a decomposition of a topographic surface into regions with vertices at the critical points and bounded by integral lines which connect passes to pits and peaks. This provides a terrain representation which encompasses the knowledge on the salient characteristics of the terrain. We classify the various techniques for computing a Morse-Smale complexe based on the underlying terrain model, a Regular Square Grid (RSG) or a Triangulated Irregular Network (TIN), and based on the algorithmic approach they apply. Finally, we discuss hierarchical terrain representations based on a Morse-Smale decomposition.

Moving Object Detection and Compression in IR Sequences - Vaswani,Namrata; Agrawal,Amit; Qinfen Zheng; Chellapa, Rama (Computer Vision Beyond the Visible SpectrumComputer Vision Beyond the Visible Spectrum, 2005)
We consider the problem of remote surveillance using infrared (IR) sensors. The aim is to use IR image sequences to detect moving objects (humans or vehicles), and to transmit a few “best-view images” of every new object that is detected. Since the available bandwidth is usually low, if the object chip is big, it needs to be compressed before being transmitted. Due to low computational power of computing devices attached to the sensor, the algorithms should be computationally simple. We present two approaches for object detection — one which specifically solves the more difficult long-range object detection problem, and the other for objects at short range. For objects at short range, we also present techniques for selecting a single best-view object chip and computationally simple techniques for compressing it to very low bit rates due to the channel bandwidth constraint. A fast image chip compression scheme implemented in the wavelet domain by combining a non-iterative zerotree coding method with 2D-DPCM for both low-and high-frequency subbands is presented. Comparisons with some existing schemes are also included. The object detection and compression algorithms have been implemented in C/C++ and their performance has been evaluated using the Hitachi’s SH4 platform with software simulation.

Moving Object Segmentation and Dynamic Scene Reconstruction Using Two Frames - Agrawala, Ashok K.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2005. Proceedings. (ICASSP '05). IEEE International Conference on, 2005)
Keywords: 3D; analysis; constraints; dynamic; ego-motion; estimation; flow; image; images; independent; INTENSITY; least; mean; median; method; methods; model; MOTION; motion; moving; object; of; parallax; parallax; parametric; processing; reconstruction; scene; segmentation; signal; squares; squares; static; structure; subspace; surface; translational; two-frame; unconstrained; video

Neuromimetic sound representation for percept detection and manipulation - Zotkin,Dmitry N; Chi,T.; Shamma,S.A.; Duraiswami, Ramani (EURASIP Journal on Applied Signal Processing, 2005)
The acoustic wave received at the ears is processed by the human auditory system to separate different sounds along the intensity,pitch, and timbre dimensions. Conventional Fourier-based signal processing, while endowed with fast algorithms, is unable to easily represent a signal along these attributes. In this paper, we discuss the creation of maximally separable sounds in auditory user interfaces and use a recently proposed cortical sound representation, which performs a biomimetic decomposition of an acoustic signal, to represent and manipulate sound for this purpose. We briefly overview algorithms for obtaining, manipulating, and inverting a cortical representation of a sound and describe algorithms for manipulating signal pitch and timbre separately. The algorithms are also used to create sound of an instrument between a “guitar” and a “trumpet.” Excellent sound quality can be achieved if processing time is not a concern, and intelligible signals can be reconstructed in reasonable processing time (about ten seconds of computational time for a one-second signal sampled at 8 kHz). Work on bringing the algorithms into the real-time processing domain is ongoing.

Non-Stationary "Shape Activities" - Vaswani, N.; Chellapa, Rama (Decision and Control, 2005 and 2005 European Control Conference. CDC-ECC '05. 44th IEEE Conference on, 2005)
The changing configuration of a group of moving landmarks can be modeled as a moving and deforming shape. The landmarks defining the shape could be moving objects(people/vehicles/robots) or rigid components of an articulated shape like the human body. In past work, the term "shape activity" has been used to denote a particular stochastic model for shape deformation. Dynamical models have been proposed for characterizing stationary shape activities (assume constant mean shape). In this work we define stochastic dynamic models for non-stationary shape activities and show that the stationary shape activity model follows as a special case of this. Most activities performed by a group of moving landmarks (here, objects) are not stationary and hence this more general model is needed. We also define a piecewise stationary model with non-stationary transitions which can be used to segment out and track a sequence of activities. Noisy observations coming from these models can be tracked using a particle filter. We discuss applications of our framework to abnormal activity detection, tracking and activity sequence segmentation.

Path dependence and the validation of agent-based spatial models of land use - Corresponding,D.G.B.; Page,S; Riolo,R; Zellner,M; Rand, William (International Journal of Geographical Information Science, 2005)

Pathogenic Vibrio species in the marine and estuarine environment - Pruzzo,C.; Huq,A.; Rita R Colwell; Donelli,G. (Oceans and health: pathogens in the marine environment, 2005)
The genus Vibrio includes more than 30 species, at least 12 of which are pathogenic to humans and/or have been associated with foodborne diseases (Chakraborty et al., 1997). Among these species, Vibrio cholerae, serogroups O1 and O139, are the most important, since they are associated with epidemic and pandemic diarrhea outbreaks in many parts of the world (Centers for Disease Control and Prevention, 1995; Kaper et al., 1995). However, other species of vibrios capable of causing diarrheal disease in humans have received greater attention in the last decade. These include Vibrio parahaemolyticus, a leading cause of foodborne disease outbreaks in Japan and Korea (Lee et al., 2001), Vibrio vulnificus, Vibrio alginolyticus, Vibrio damsela, Vibrio fluvialis, Vibrio furnissii, Vibrio hollisae, Vibrio metschnikovii, and Vibrio mimicus (Altekruse et al., 2000; Høi et al., 1997). In the USA, Vibrio species have been estimated to be the cause of about 8000 illnesses annually (Mead et al., 1999).

Pattern Recognition in Video - Chellapa, Rama; Veeraraghavan,Ashok; Aggarwal,Gaurav (Pattern Recognition and Machine IntelligencePattern Recognition and Machine Intelligence, 2005)
Images constitute data that live in a very high dimensional space, typically of the order of hundred thousand dimensions. Drawing inferences from correlated data of such high dimensions often becomes intractable. Therefore traditionally several of these problems like face recognition, object recognition, scene understanding etc. have been approached using techniques in pattern recognition. Such methods in conjunction with methods for dimensionality reduction have been highly popular and successful in tackling several image processing tasks. Of late, the advent of cheap, high quality video cameras has generated new interests in extending still image-based recognition methodologies to video sequences. The added temporal dimension in these videos makes problems like face and gait-based human recognition, event detection, activity recognition addressable. Our research has focussed on solving several of these problems through a pattern recognition approach. Of course, in video streams patterns refer to both patterns in the spatial structure of image intensities around interest points and temporal patterns that arise either due to camera motion or object motion. In this paper, we discuss the applications of pattern recognition in video to problems like face and gait-based human recognition, behavior classification, activity recognition and activity based person identification.

Pose-Encoded Spherical Harmonics for Robust Face Recognition Using a Single Image - Yue,Zhanfeng; Zhao,Wenyi; Chellapa, Rama (Analysis and Modelling of Faces and GesturesAnalysis and Modelling of Faces and Gestures, 2005)
Face recognition under varying pose is a challenging problem, especially when illumination variations are also present. Under Lambertian model, spherical harmonics representation has proved to be effective in modelling illumination variations for a given pose. In this paper, we extend the spherical harmonics representation to encode pose information. More specifically, we show that 2D harmonic basis images at different poses are related by close-form linear combinations. This enables an analytic method for generating new basis images at a different pose which are typically required to handle illumination variations at that particular pose. Furthermore, the orthonormality of the linear combinations is utilized to propose an efficient method for robust face recognition where only one set of front-view basis images per subject is stored. In the method, we directly project a rotated testing image onto the space of front-view basis images after establishing the image correspondence. Very good recognition results have been demonstrated using this method.

Pose-normalized view synthesis from silhouettes - Yue, Z.; Chellapa, Rama (IEEE Intl. Conf. on Acoustics, Speech, and Signal Processing (ICASSP), 2005)
In this paper, we introduce an active view synthesis approachfrom silhouettes. With the virtual camera moving on a properly se- lected circular trajectory around an object of interest, we achieve a collection of virtual views of the object, which is equivalent to the case that the object is on a rotating turntable and captured by a static camera whose optical axis is parallel to the turntable. We show how to derive the virtual camera’s extrinsic parameters at each position on the trajectory. Using the turning function dis- tance as the silhouette similarity measurement, this approach can be used to generate the desired pose-normalized images for recog- nition applications.

Probabilistic temporal logics via the modal mu-calculus - Cleaveland, Rance; Iyer,S. Purushothaman; Narasimha,Murali (Theoretical Computer Science, 2005)
This paper presents a mu-calculus-based modal logic for describing properties of reactive probabilistic labeled transition systems (RPLTSs) and develops a model-checking algorithm for determining whether or not states in finite-state RPLTSs satisfy formulas in the logic. The logic is based on the distinction between (probabilistic) â€œsystemsâ€ and (nonprobabilistic) â€œobservationsâ€: using the modal mu-calculus, one may specify sets of observations, and the semantics of our logic then enable statements to be made about the measures of such sets at various system states. The logic may be used to encode a variety of probabilistic modal and temporal logics; in addition, the model-checking problem for it may be reduced to the calculation of solutions to systems of non-linear equations. Finally, the logic induces an equivalence on RPLTSs that coincides with accepted notions of probabilistic bisimulation in the literature.
Keywords: Model-checking; Probabilistic bisimulation; Probabilistic temporal logic; Probabilistic transition systems; reactive systems

Real-time foreground-background segmentation using codebook model - Kim,K.; Chalidabhongse,T.H.; Harwood,D.; Davis, Larry S. (Real-time imaging, 2005)

Recognition of Humans and Their Activities Using Video - Chellapa, Rama; Roy-Chowdhury,Amit K.; Zhou,S. Kevin (Synthesis Lectures on Image, Video, and Multimedia Processing, 2005)
The recognition of humans and their activities from video sequences is currently a very active area of research because of its applications in video surveillance, design of realistic entertainment systems, multimedia communications, and medical diagnosis. In this lecture, we discuss the use of face and gait signatures for human identification and recognition of human activities from video sequences. We survey existing work and describe some of the more well-known methods in these areas. We also describe our own research and outline future possibilities.In the area of face recognition, we start with the traditional methods for image-based analysis and then describe some of the more recent developments related to the use of video sequences, 3D models, and techniques for representing variations of illumination. We note that the main challenge facing researchers in this area is the development of recognition strategies that are robust to changes due to pose, illumination, disguise, and aging. Gait recognition is a more recent area of research in video understanding, although it has been studied for a long time in psychophysics and kinesiology. The goal for video scientists working in this area is to automatically extract the parameters for representation of human gait. We describe some of the techniques that have been developed for this purpose, most of which are appearance based. We also highlight the challenges involved in dealing with changes in viewpoint and propose methods based on image synthesis, visual hull, and 3D models. In the domain of human activity recognition, we present an extensive survey of various methods that have been developed in different disciplines like artificial intelligence, image processing, pattern recognition, and computer vision. We then outline our method for modeling complex activities using 2D and 3D deformable shape theory. The wide application of automatic human identification and activity recognition methods will require the fusion of different modalities like face and gait, dealing with the problems of pose and illumination variations, and accurate computation of 3D models. The last chapter of this lecture deals with these areas of future research.

Representing Unevenly-Spaced Time Series Data for Visualization and Interactive Exploration - Aris,Aleks; Shneiderman, Ben; Plaisant, Catherine; Shmueli,Galit; Jank,Wolfgang (Human-Computer Interaction - INTERACT 2005Human-Computer Interaction - INTERACT 2005, 2005)
Visualizing time series is useful to support discovery of relations and patterns in financial, genomic, medical and other applications. Often, measurements are equally spaced over time. We discuss the challenges of unevenly-spaced time series and present fourrepresentationmethods: sampled events, aggregated sampled events, event index and interleaved event index. We developed these methods while studying eBay auction data with TimeSearcher. We describe the advantages, disadvantages, choices for algorithms and parameters, and compare the different methods for different tasks. Interaction issues such as screen resolution, response time for dynamic queries, and learnability are governed by these decisions.

Scheduling on Unrelated Machines Under Tree-Like Precedence Constraints - Kumar, V.; Marathe,Madhav; Parthasarathy,Srinivasan; Srinivasan, Aravind (Approximation, Randomization and Combinatorial Optimization. Algorithms and TechniquesApproximation, Randomization and Combinatorial Optimization. Algorithms and Techniques, 2005)
We present polylogarithmic approximations for the R | prec | C max and R | prec |∑ j w j C j problems, when the precedence constraints are “treelike” – i.e., when the undirected graph underlying the precedences is a forest. We also obtain improved bounds for the weighted completion time and flow time for the case of chains with restricted assignment – this generalizes the job shop problem to these objective functions. We use the same lower bound of “congestion+dilation”, as in other job shop scheduling approaches. The first step in our algorithm for the R | prec | C max problem with treelike precedences involves using the algorithm of Lenstra, Shmoys and Tardos to obtain a processor assignment with the congestion + dilation value within a constant factor of the optimal. We then show how to generalize the random delays technique of Leighton, Maggs and Rao to the case of trees. For the weighted completion time, we show a certain type of reduction to the makespan problem, which dovetails well with the lower bound we employ for the makespan problem. For the special case of chains, we show a dependent rounding technique which leads to improved bounds on the weighted completion time and new bicriteria bounds for the flow time.

Secure requirements elicitation through triggered message sequence charts - Ray,A.; Sengupta,B.; Cleaveland, Rance (Distributed Computing and Internet Technology, 2005)

"Shape Activity": a continuous-state HMM for moving/deforming shapes with application to abnormal activity detection - Vaswani, N.; Roy-Chowdhury, A.K.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2005)
The aim is to model "activity" performed by a group of moving and interacting objects (which can be people, cars, or different rigid components of the human body) and use the models for abnormal activity detection. Previous approaches to modeling group activity include co-occurrence statistics (individual and joint histograms) and dynamic Bayesian networks, neither of which is applicable when the number of interacting objects is large. We treat the objects as point objects (referred to as "landmarks") and propose to model their changing configuration as a moving and deforming "shape" (using Kendall's shape theory for discrete landmarks). A continuous-state hidden Markov model is defined for landmark shape dynamics in an activity. The configuration of landmarks at a given time forms the observation vector, and the corresponding shape and the scaled Euclidean motion parameters form the hidden-state vector. An abnormal activity is then defined as a change in the shape activity model, which could be slow or drastic and whose parameters are unknown. Results are shown on a real abnormal activity-detection problem involving multiple moving objects.
Keywords: abnormal activity detection; activity recognition; co-occurrence statistics; continuous-state hidden Markov model; dynamic Bayesian networks; hidden-state vector; particle filtering; scaled Euclidean motion parameter; shape deforming; belief networks; filtering the; Automated; Subtraction Technique; Video Recording; Biological; Models; Computer-Assisted; Information Storage and Retrieval; Markov Chains; Models; Statistical; Movement; Pattern Recognition

A simulation and data analysis system for large-scale, data-driven oil reservoir simulation studies - Kurc, T.; Catalyurek,U.; Zhang,X.; Saltz, J.; Martino,R.; Wheeler,M.; Peszyńska,M.; Sussman, Alan; Hansen,C.; Sen,M.; others (Concurrency and Computation: Practice and Experience, 2005)

Social and Psychological Influences on Computer User Frustration (Newhagen book chapter, 2002) - Bessiere,Katie; Ceaparu,Irina; Lazar,Jonathan; Robinson,John; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
As computer usage has proliferated, so has user frustration. Even devoted and knowledgeable users encounter annoying delays, incomprehensible messages, incompatible files, and indecipherable menus. The frustration generated by these problems can be personally disturbing and socially disruptive. Psychological and social perspectives on frustration may clarify the relationships among variables such as personality types, cultural factors, goal attainment, workplace anger, and computer anxiety. These perspectives may also help designers, managers, and users understand the range of responses to frustration, which could lead to effective interventions such as redesign of software, improved training, better online help, user discipline, and even resetting of national research priorities.
Keywords: Technical Report

Statistical bias in 3-D reconstruction from a monocular video - Roy-Chowdhury, A.K.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2005)
The present state-of-the-art in computing the error statistics in three-dimensional (3-D) reconstruction from video concentrates on estimating the error covariance. A different source of error which has not received much attention is the fact that the reconstruction estimates are often significantly statistically biased. In this paper, we derive a precise expression for the bias in the depth estimate, based on the continuous (differentiable) version of structure from motion (SfM). Many SfM algorithms, or certain portions of them, can be posed in a linear least-squares (LS) framework Ax=b. Examples include initialization procedures for bundle adjustment or algorithms that alternately estimate depth and camera motion. It is a well-known fact that the LS estimate is biased if the system matrix A is noisy. In SfM, the matrix A contains point correspondences, which are always difficult to obtain precisely; thus, it is expected that the structure and motion estimates in such a formulation of the problem would be biased. Existing results on the minimum achievable variance of the SfM estimator are extended by deriving a generalized Cramer-Rao lower bound. A detailed analysis of the effect of various camera motion parameters on the bias is presented. We conclude by presenting the effect of bias compensation on reconstructing 3-D face models from rendered images.
Keywords: 3D face models; 3D video reconstruction; algorithms; artifacts; Artificial intelligence; Automated; Signal Processing; bias compensation; bundle adjustment; camera motion estimation; Computer simulation; Computer-Assisted; Imaging; Computer-Assisted; Subtraction Technique; Video Recording; depth estimate; error covariance estimation; error statistics; generalized Cramer-Rao lower bound; Image Enhancement; Image Interpretation; Image reconstruction; initialization procedures; least squares approximations; linear least-squares framework; monocular video; motion compensation; Motion estimation; statistical bias; Statistical; Pattern Recognition; structure from motion algorithms; Three-Dimensional; Information Storage and Retrieval; Models; video signal processing

Synthesis of novel views of moving objects in airborne video - Yue, Z.; Chellapa, Rama (Proc. British Machine Vision Conference, 2005)
This paper presents a method for synthesizing novel views of movingobjects in airborne video. The object of interest is tracked using an appear- ance based visual tracking method. The on-object point correspondence is then built and used to estimate the homography induced by the ground plane. With known camera focal length, the surface normal to the ground plane and the camera motion between two views are factored out from the homography. In order to assure robustness of surface normal estimation, a rank one con- straint is applied to decompose a matrix which contains the homographies from multiple frame pairs. Given a desired viewing direction, the novel im- age of the object is generated by warping the reference frame using the new homography between the desired viewpoint and the reference frame. Exper- imental results show that the method is robust and errors due to small depth variations of the object is negligible.

Temperature-Driven Campylobacter Seasonality in England and Wales - Louis,Valérie R.; Gillespie,Iain A.; O'Brien,Sarah J.; Russek-Cohen,Estelle; Pearson,Andrew D.; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2005)
Campylobacter incidence in England and Wales between 1990 and 1999 was examined in conjunction with weather conditions. Over the 10-year interval, the average annual rate was determined to be 78.4 ± 15.0 cases per 100,000, with an upward trend. Rates were higher in males than in females, regardless of age, and highest in children less than 5 years old. Major regional differences were detected, with the highest rates in Wales and the southwest and the lowest in the southeast. The disease displayed a seasonal pattern, and increased campylobacter rates were found to be correlated with temperature. The most marked seasonal effect was observed for children under the age of 5. The seasonal pattern of campylobacter infections indicated a linkage with environmental factors rather than food sources. Therefore, public health interventions should not be restricted to food-borne approaches, and the epidemiology of the seasonal peak in human campylobacter infections may best be understood through studies in young children.

Tracking Algorithm Using Background-Foreground Motion Models and Multiple Cues - Shao, J.; Zhou,S. K; Chellapa, Rama (ICASSP apos, 2005)
We present a stochastic tracking algorithm for surveillance videoswhere targets are dim and of low resolution. Our tracker is mainly based on the particle filter algorithm. Two important novel fea- tures of the tracker include: A motion model consisting of both background and foreground motion parameters is built. Multiple cues are adaptively integrated in a system observation model when estimating the likelihood functions. Based on these features, the accuracy and robustness of the tracker has been improved, which is very important for surveillance problems. We present the results of applying the proposed algorithm to many videos.

Tracking objects in video using motion and appearance models - Sankaranarayanan,A. C; Chellapa, Rama; Qinfen Zheng (Image Processing, 2005. ICIP 2005. IEEE International Conference on, 2005)
This paper proposes a visual tracking algorithm that combines motion and appearance in a statistical framework. It is assumed that image observations are generated simultaneously from a background model and a target appearance model. This is different from conventional appearance-based tracking, that does not use motion information. The proposed algorithm attempts to maximize the likelihood ratio of the tracked region, derived from appearance and background models. Incorporation of motion in appearance based tracking provides robust tracking, even when the target violates the appearance model. We show that the proposed algorithm performs well in tracking targets efficiently over long time intervals.
Keywords: algorithm; analysis; appearance; background; estimation; image; likelihood; maximum; model; models; MOTION; object; processing; signal; target; tracking; tracking; video; visual

Transcriptional profiling of the hyperthermophilic methanarchaeon Methanococcus jannaschii in response to lethal heat and non‐lethal cold shock - Boonyaratanakornkit,Boonchai B; Simpson,Anjana J.; Whitehead,Timothy A; Fraser,Claire M.; El‐Sayed, Najib M.; Clark,Douglas S (Environmental Microbiology, 2005)
Temperature shock of the hyperthermophilic methanarchaeon Methanococcus jannaschii from its optimal growth temperature of 85°C to 65°C and 95°C resulted in different transcriptional responses characteristic of both the direction of shock (heat or cold shock) and whether the shock was lethal. Specific outcomes of lethal heat shock to 95°C included upregulation of genes encoding chaperones, and downregulation of genes encoding subunits of the H+ transporting ATP synthase. A gene encoding an α subunit of a putative prefoldin was also upregulated, which may comprise a novel element in the protein processing pathway in M. jannaschii. Very different responses were observed upon cold shock to 65°C. These included upregulation of a gene encoding an RNA helicase and other genes involved in transcription and translation, and upregulation of genes coding for proteases and transport proteins. Also upregulated was a gene that codes for an 18 kDa FKBP-type PPIase, which may facilitate protein folding at low temperatures. Transcriptional profiling also revealed several hypothetical proteins that respond to temperature stress conditions.

UMD Experiments with FRGC Data - Aggarwal,G.; Biswas,S.; Chellapa, Rama (Computer Vision and Pattern Recognition - Workshops, 2005. CVPR Workshops. IEEE Computer Society Conference on, 2005)
Although significant work has been done in the field of face recognition, the performance of state-of-the art face recognition algorithms is not good enough to be effective in operational systems. Though most algorithms work well for controlled images, they are quite susceptible to changes in illumination and pose. Face Recognition Grand Challenge (FRGC) is an effort to examine such issues to suitably guide future research in the area. This paper describes the efforts made at UMD in this direction. We present our results on several experiments suggested in FRGC. We believe that though pattern classification techniques play an extremely significant role in automatic face recognition under controlled conditions, physical modeling is required to generalize across varying situations. Accordingly, we describe a generative approach to recognize faces across varying illumination. Unlike most current methods, our method does not ignore shadows. Instead we use them to our benefit by modeling attached shadows in our formulation.

Universally composable password-based key exchange - Canetti,R.; Halevi,S.; Katz, Jonathan; Lindell,Y.; MacKenzie,P. (Advances in Cryptology–Eurocrypt 2005, 2005)
We propose and realize a definition of security for password-based key exchange within the framework of universally composable (UC) security, thus providing security guarantees under arbitrary composition with other protocols. In addition, our definition captures some aspects of the problem that were not adequately addressed by most prior notions. For instance, it does not assume any underlying probability distribution on passwords, nor does it assume independence between passwords chosen by different parties. We also formulate a definition of password-based secure channels, and show that such a definition is achievable given password-based key exchange.Our protocol realizing the new definition of password-based key exchange is in the common reference string model and relies on standard number-theoretic assumptions. The components of our protocol can be instantiated to give a relatively efficient solution which is conceivably usable in practice. We also show that it is impossible to satisfy our definition in the “plain” model (e.g., without a common reference string).

User Frustration with Technology in the Workplace (2004) - Lazar,Jonathan; Jones,Adam; Bessiere,Katie; Ceaparu,Irina; Shneiderman, Ben (Institute for Systems Research Technical Reports, 2005)
When hard to use computers cause users to become frustrated, it can affect workplace productivity, user mood, and interactions with other co-workers. Previous research has examined the frustration that graduate students and their families face in using computers. To learn more about the causes and effects of user frustration with computers in the workplace, we collected modified time diaries from 50 workplace users, who spent an average of 5.1 hours on the computer. In this experiment, users reported wasting on average, 42-43% of their time on the computer due to frustrating experiences. The causes of the frustrating experiences, the time lost due to the frustrating experiences, and the effects of the frustrating experiences on the mood of the users are discussed in this paper. Implications for designers, managers, users, information technology staff, and policymakers are discussed.
Keywords: Technical Report

Using Iterative Strategies for Aligning Attributed Points in Space - Cardone, Antonio; Gupta, Satyandra K.; Mount, Dave (Institute for Systems Research, University of Maryland, College Park, 2005)
Signatures based on shape features are expected to be useful for several similarity assessment applications. Such signatures can extract the relevant shape information needed for similarity assessment and ignore the shape information not needed for a particular application. Since different feature-based models are created in different coordinate systems, in order to compute distance between two sets of features, one needs to include geometric transformations for aligning features. Optimal alignment is the alignment that results in the minimum distance between two sets of features. In general, features can be viewed as attributed points in space. Hence, we need to develop techniques for aligning attributed points in space. This report introduces iterative strategies for optimally aligning attributed points in space. Iterative strategies presented in this report involve successively applying algorithms that perform alignment under restricted rigid body transformations (e.g., rotations only or translations only) to solve point alignment problems that require higher dimension transformations (e.g., combinations rotations and translations). Our preliminary experimental results show that the idea of using of iterative strategies to solve higher dimension attributed point alignment problems is promising and can be used to perform feature-based shape similarity assessment.
Keywords: Technical Report

Visualizing Missing Data: Graph Interpretation User Study - Eaton,Cyntrica; Plaisant, Catherine; Drizd,Terence (Human-Computer Interaction - INTERACT 2005, 2005)
Most visualization tools fail to provide support for missing data. In this paper, we identify sources of missing data and describe three levels of impact missing data can have on the visualization: perceivable, invisible or propagating. We then report on a user study with 30 participants that compared three design variants. A between-subject graph interpretation study provides strong evidence for the need of indicating the presence of missing information, and some direction for addressing the problem.

3D model refinement using surface-parallax - Agrawala, Ashok K.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, 2004)
We present an approach to update and refine coarse 3D models of urban environments from a sequence of intensity images using surface parallax. This generalizes the plane-parallax recovery methods to surface-parallax using arbitrary surfaces. A coarse and potentially incomplete depth map of the scene obtained from a digital elevation map (DEM) is used as a reference surface which is refined and updated using this approach. The reference depth map is used to estimate the camera motion and the motion of the 3D points on the reference surface is compensated. The resulting parallax, which is an epipolar field, is estimated using an adaptive windowing technique and used to obtain the refined depth map.
Keywords: 3D; adaptive; arbitrary; camera; coarse; compensation; Computer; DEM; depth; digital; ELEVATION; environments; epipolar; estimation; field; image; incomplete; INTENSITY; map; model; MOTION; parallax; plane-parallax; reconstruction; recovery; refinement; sequence; sequences; surface; surfaces; urban; vision; windowing

3d modelling of human motion using kinematic chains and multiple cameras for tracking - Sundaresan, A.; RoyChowdhury, A.; Chellapa, Rama (Proc. of Eighth International Symposium on the, 2004)

Abstracting workflows: unifying bioinformatics task conceptualization and specification through Semantic Web services - Hashmi,N.; Lee,S.; Cummings, Michael P. (W3C Workshop on Semantic Web for Life Sciences, 2004)

Acinetobacter lipases: molecular biology, biochemical properties and biotechnological potential - Snellman,E. A.; Rita R Colwell (Journal of industrial microbiology & biotechnology, 2004)
Lipases (EC 3.1.1.3) have received increased attention recently, evidenced by the increasing amount of information about lipases in the current literature. The renewed interest in this enzyme class is due primarily to investigations of their role in pathogenesis and their increasing use in biotechnological applications [38]. Also, many microbial lipases are available as commercial products, the majority of which are used in detergents, cosmetic production, food flavoring, and organic synthesis. Lipases are valued biocatalysts because they act under mild conditions, are highly stable in organic solvents, show broad substrate specificity, and usually show high regio- and/or stereo-selectivity in catalysis. A number of lipolytic strains of Acinetobacter have been isolated from a variety of sources and their lipases possess many biochemical properties similar to those that have been developed for biotechnological applications. This review discusses the biology of lipase expression in Acinetobacter, with emphasis on those aspects relevant to potential biotechnology applications.

Adaptively-Secure, Non-Interactive Public-Key Encryption - Canetti,R.; Halevi,S.; Katz, Jonathan (Model reduction methods for vector autoregressive processes, 2004)

Appearance tracking using adaptive models in a particle filter - Zhou, S.; Chellapa, Rama; Moghaddam, B. (Proc. of 6th Asian Conference on Computer Vision (ACCV), 2004)
The particle filter is a popular tool for visual tracking. Usually, the appearance model is eitherfixed or rapidly changing and the motion model is simply a random walk with fixed noise vari- ance. Also, the number of particles used is typically fixed. All these factors make the visual tracker unstable. To stabilize the tracker, we propose the following measures: an observation model arising from an adaptive noise variance, and adaptive number of particles. The adaptive- velocity is computed via a first-order linear predictor using the previous particle configuration. Tracking under occlusion is accomplished using robust statistics. Experimental results on track- ing visual objects in long video sequences such as vehicles, tank, and human faces demonstrate the effectiveness and robustness of our algorithm.

Appearance-based tracking and recognition using the 3D trilinear tensor - Jie Shao; Zhou,S. K; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, 2004)
The paper presents an appearance-based adaptive algorithm for simultaneous tracking and recognition by generalizing the transformation model to 3D perspective transformation. A trilinear tensor operator is used to represent the 3D geometrical structure. The tensor is estimated by predicting the corresponding points using the existing affine-transformation based algorithm. The estimated tensor is used to synthesize novel views to update the appearance templates. Some experimental results using airborne video are presented.
Keywords: 3D; adaptive; affine-transformation; airborne; algorithm; appearance; appearance-based; based; estimation; geometrical; image; mathematical; novel; object; operator; operators; perspective; prediction; processing; recognition; representation; signal; structure; synthesis; template; tensor; tensor; tensors; tracking; transformation; trilinear; updating; video; video-based; video; view

Applying permutation tests to tree-based statistical models: extending the R package rpart - Cummings, Michael P.; Myers,D. S; Mangelson,M (University of Maryland Institute for Advanced Computer Studies, 2004)
Tree-based statistical models are useful for evaluating relationships between predictor and response variables and for generating predictions when the response is unknown. However, current methods of constructing tree-based models do not provide a probabilistic assessment of the models produced. Here we describe our work to use permutation tests to quantitatively estimate the probability of tree-based statistical models. We have extended the rpart (recursive partitioning) package of the R system for statistical data analysis. This extension, rpart.permutation, executes the permutations in parallel, using MPI (Message Passing Interface) to greatly decrease the time necessary to complete the analysis.

Automated cluster-based Web service performance tuning - Chung,I. -H; Hollingsworth, Jeffrey K (13th IEEE International Symposium on High performance Distributed Computing, 2004. Proceedings, 2004)
Active harmony provides a way to automate performance tuning. We apply the Active Harmony system to improve the performance of a cluster-based web service system. The performance improvement cannot easily be achieved by tuning individual components for such a system. The experimental results show that there is no single configuration for the system that performs well for all kinds of workloads. By tuning the parameters, Active Harmony helps the system adapt to different workloads and improve the performance up to 16%. For scalability, we demonstrate how to reduce the time when tuning a large system with many tunable parameters. Finally an algorithm is proposed to automatically adjust the structure of cluster-based web systems, and the system throughput is improved up to 70% using this technique.
Keywords: Active Harmony system; automated performance tuning; business; cluster-based Web service system; Clustering algorithms; Computer science; Educational institutions; electronic commerce; Internet; Middleware; performance evaluation; scalability; Throughput; Transaction databases; Web server; Web services; workstation clusters

Background modeling and subtraction by codebook construction - Kim,Kyungnam; Chalidabhongse,T.H.; Harwood,D.; Davis, Larry S. (Image Processing, 2004. ICIP '04. 2004 International Conference on, 2004)
We present a new fast algorithm for background modeling and subtraction. Sample background values at each pixel are quantized into codebooks which represent a compressed form of background model for a long image sequence. This allows us to capture structural background variation due to periodic-like motion over a long period of time under limited memory. Our method can handle scenes containing moving backgrounds or illumination variations (shadows and highlights), and it achieves robust detection for compressed videos. We compared our method with other multimode modeling techniques.
Keywords: (signal); analysis; background; codebook; coding; colour; compression; construction; data; image; modeling; modeling; MOTION; multimode; quantisation; representation; sequence; sequences; subtraction; technique; video

Bayesian self-calibration of a moving camera - Qian,Gang; Chellapa, Rama (Computer Vision and Image Understanding, 2004)
In this paper, a Bayesian self-calibration approach using sequential importance sampling (SIS) is proposed. Given a set of feature correspondences tracked through an image sequence, the joint posterior distributions of both camera extrinsic and intrinsic parameters as well as the scene structure are approximated by a set of samples and their corresponding weights. The critical motion sequences are explicitly considered in the design of the algorithm. The probability of the existence of the critical motion sequence is inferred from the sample and weight set obtained from the SIS procedure. No initial guess for the calibration parameters is required. The proposed approach has been extensively tested on both synthetic and real image sequences and satisfactory performance has been observed.
Keywords: self-calibration; Sequential Monte Carlo methods; structure from motion; video analysis

A book like its cover - Cummings, Michael P. (Heredity, 2004)
An official journal of the Genetics Society, Heredity publishes high-quality articles describing original research and theoretical insights in all areas of genetics. Research papers are complimented by News & Commentary articles and reviews, keeping researchers and students abreast of hot topics in the field.
Keywords: animal and plant breeding; biometrical and statistical genetics; cytogenetics; ecological; eukaryotes; Genetics; Genomics; human population genetics; population and evolutionary genetics; post-genomics

Challenges in Measuring HPCS Learner Productivity in an Age of Ubiquitous Computing: The HPCS Program - Asgari, S.; Basili, Victor R.; Carver, J.; Hochstein, L.; Hollingsworth, Jeffrey K; Zelkowitz, Marvin V (In Proceedings of ICSE Workshop on High Productivity Computing. May 2004, 2004)

Characterization of human faces under illumination variations using rank, integrability, and symmetry constraints - Zhou, S.; Chellapa, Rama; Jacobs, David W. (Computer Vision-ECCV 2004, 2004)
Photometric stereo algorithms use a Lambertian reflectance model with a varying albedo field and involve the appearances of only one object. This paper extends photometric stereo algorithms to handle all the appearances of all the objects in a class, in particular the class of human faces. Similarity among all facial appearances motivates a rank constraint on the albedos and surface normals in the class. This leads to a factorization of an observation matrix that consists of exemplar images of different objects under different illuminations, which is beyond what can be analyzed using bilinear analysis. Bilinear analysis requires exemplar images of different objects under same illuminations. To fully recover the class-specific albedos and surface normals, integrability and face symmetry constraints are employed. The proposed linear algorithm takes into account the effects of the varying albedo field by approximating the integrability terms using only the surface normals. As an application, face recognition under illumination variation is presented. The rank constraint enables an algorithm to separate the illumination source from the observed appearance and keep the illuminant-invariant information that is appropriate for recognition. Good recognition results have been obtained using the PIE dataset.

Chosen-ciphertext security from identity-based encryption - Canetti,R.; Halevi,S.; Katz, Jonathan (Advances in Cryptology-Eurocrypt 2004, 2004)
We propose a simple and efficient construction of a CCA-secure public-key encryption scheme from any CPA-secure identity-based encryption (IBE) scheme. Our construction requires the underlying IBE scheme to satisfy only a relatively “weak” notion of security which is known to be achievable without random oracles; thus, our results provide a new approach for constructing CCA-secure encryption schemes in the standard model. Our approach is quite different from existing ones; in particular, it avoids non-interactive proofs of “well-formedness” which were shown to underlie most previous constructions. Furthermore, applying our conversion to some recently-proposed IBE schemes results in CCA-secure schemes whose efficiency makes them quite practical.Our technique extends to give a simple and reasonably efficient method for securing any binary tree encryption (BTE) scheme against adaptive chosen-ciphertext attacks. This, in turn, yields more efficient CCA-secure hierarchical identity-based and forward-secure encryption schemes in the standard model.

Classification probability analysis of principal component space analysis - Vaswani, N.; Chellapa, Rama (Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on, 2004)
In a previous paper, we have presented a new linear classification algorithm, principal component space analysis (PCNSA) which is designed for problems like object recognition where different classes have unequal and non-white noise covariance matrices. PCNSA first obtains a principal components space (PCA space) for the entire data and in this PCA space, it finds for each class "i", an Mi dimensional subspace along which the class's intra-class 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's mean in the class's ANS is a minimum. In this paper, we discuss the PCNSA algorithm more precisely and derive tight upper bounds on its classification error probability. We use these expressions to compare classification performance of PCNSA with that of subspace linear discriminant analysis (SLDA).
Keywords: algorithm; analysis; approximate; classification; classification; component; covariance; discriminant; error; intraclass; linear; matrices; matrix; noise; nonwhite; object; pattern; PCA; principal; probability; recognition; space; space; statistics; subspace; variance

Contour-based 3D Face Modeling from a Monocular Video - Gupta, H.; Roy Chowdhury, A.K.; Chellapa, Rama (Proceedings of the British Machine Vision Conference, 2004)
In this paper, we present a novel 3D face modeling approach from a monoc-ular video captured using a conventional camera. The proposed algorithm relies on matching a generic 3D face model to the outer contours of the face to be modeled and a few of its internal features. At the first stage of the method, we estimate the head pose by comparing the edges extracted from video frames, with the contours extracted from a generic face model. Next, the generic face model is adapted to the actual 3D face by global and local deformations. An affine model is used for global deformation. The 3D model is locally deformed by computing the optimal perturbations of a sparse set of control points using a stochastic search optimization method. The deforma- tions are integrated over a set of poses in the video sequence, leading to an accurate 3D model.

Covering arrays for efficient fault characterization in complex configuration spaces - Yilmaz,C.; Cohen,M. B; Porter, Adam (ACM SIGSOFT Software Engineering Notes, 2004)

Data sciences technology for homeland security information management and knowledge discovery - Kolda,T.; Brown,D; Corones,J.; Critchlow,T.; Eliassi-Rad,T.; Getoor, Lise; Hendrickson,B.; Kumar, V.; Lambert,D.; Matarazzo,C. (Report of the DHS Workshop Data Sciences, Jointly Released by Sandia National Laboratories and Lawrence Livermore National Laboratory, Alexandria, Va, 2004)

DateLens: A fisheye calendar interface for PDAs - Bederson, Benjamin B.; Clamage,A.; Czerwinski,M.P.; Robertson,G.G. (ACM Transactions on Computer-Human Interaction (TOCHI), 2004)

Determining Causes and Severity of End-User Frustration - Ceaparu,Irina; Lazar,Jonathan; Bessiere,Katie; Robinson,John; Shneiderman, Ben (International Journal of Human-Computer Interaction, 2004)
Although computers are beneficial to individuals and society, frequently users encounter frustrating experiences when using computers. This study represents an attempt to measure, in 111 participants, the frequency, the cause, and the level of severity of frustrating experiences. The data show that frustrating experiences happen on a frequent basis. The applications in which the frustrating experiences happened most frequently were Web browsing, e-mail, and word processing. The most-cited causes of frustrating experiences were error messages, dropped network connections, long download times, and hard-to-find features. The time lost due to frustrating experiences ranged from 47% to 53% of time spent on a computer, depending on the location and study method. After extreme cases were discarded, the time lost was still above 38%. These disturbing results should be a basis for future study.Although computers are beneficial to individuals and society, frequently users encounter frustrating experiences when using computers. This study represents an attempt to measure, in 111 participants, the frequency, the cause, and the level of severity of frustrating experiences. The data show that frustrating experiences happen on a frequent basis. The applications in which the frustrating experiences happened most frequently were Web browsing, e-mail, and word processing. The most-cited causes of frustrating experiences were error messages, dropped network connections, long download times, and hard-to-find features. The time lost due to frustrating experiences ranged from 47% to 53% of time spent on a computer, depending on the location and study method. After extreme cases were discarded, the time lost was still above 38%. These disturbing results should be a basis for future study.

Developing Locally Relevant Software Applications for Rural Areas: A South African Example - Marshini Chetty; Tucker, William; Blake, Edwin (SAICSIT '04, 2004)
The digital divide between rural and urban areas within developing countries is vast. We investigate how to address this divide by introducing Information and Communication Technologies (ICTs) into remote rural areas. Our aim is to discover how to create locally relevant software applications with appropriate content for these areas. We use a user centred design approach and a modified software development lifecyle that is participatory, iterative and cyclical. This process is based on principles from Participatory Design and Action Research. This paper presents our initial experience of developing a telemedicine application for a rural village in the Eastern Cape Province of South Africa using this process. We present an overview of the methodology, describe the software application we have developed and cite several challenges we have faced. Finally we conclude that an inter-organisational and inter-disciplinary approach is needed to develop software for remote areas.
Keywords: action research; design; human factors; participatory design; telemedicine

Dimensionality Estimation in Hyperspectral Imagery Using Minimum Description Length - Broadwater,Joshua B; Meth,Reuven; Chellapa, Rama (MARYLAND UNIV COLLEGE PARK CENTER FOR AUTOMATION RESEARCH, 2004)
Numerous algorithms have been developed for hyperspectral automatic target recognition (ATR) applications. Many of these algorithms require estimation of a background subspace. The estimation of the background subspace has been addressed using multiple methods. but most of these methods assume a-priori knowledge of the background dimensionality. In order to automate the estimation of the background subspace. we present an algorithm based on minimum description length (MDL) that can identify the background dimension. Results show that the MDL criterion estimates the proper dimension of the background for ATR applications.
Keywords: *ALGORITHMS; *HYPERSPECTRAL IMAGERY; *TARGET DETECTION; *TARGET RECOGNITION; AUTOMATIC; BURIED OBJECTS; COMPONENT REPORTS; MINE DETECTION; NUMERICAL MATHEMATICS; SURFACE TARGETS.; SYMPOSIA; TARGET DIRECTION, RANGE AND POSITION FINDING

Distributed prototyping from validated specifications - Hansel,David; Cleaveland, Rance; Smolka,Scott A. (Journal of Systems and Software, 2004)
We present vpl2cxx, a translator that automatically generates efficient, fully distributed C++ code from high-level system models specified in the mathematically well-founded VPL design language. As the Concurrency Workbench of the New Century (CWB-NC) verification tool includes a front-end for VPL, designers may use the full range of automatic verification and simulation checks provided by this tool on their VPL system designs before invoking the translator, thereby generating distributed prototypes from validated specifications. Besides being fully distributed, the code generated by vpl2cxx is highly readable and portable to a host of execution environments and real-time operating systems (RTOSes). This is achieved by encapsulating all generated code dealing with low-level interprocess communication issues in a library for synchronous communication, which in turn is built upon the adaptive communication environment (ACE) client-server network programming interface. Finally, example applications show that the performance of the generated code is very good, especially for prototyping purposes. We discuss two such examples, including the RETHER real-time Ethernet protocol for voice and video applications.

Divergent Gene Copies in the Asexual Class Bdelloidea (Rotifera) Separated Before the Bdelloid Radiation or Within Bdelloid Families - Welch,David B. Mark; Cummings, Michael P.; Hillis,David M; Meselson,Matthew (Proceedings of the National Academy of Sciences of the United States of AmericaPNAS, 2004)
Rotifers of the asexual class Bdelloidea are unusual in possessing two or more divergent copies of every gene that has been examined. Phylogenetic analysis of the heat-shock gene hsp82 and the TATA-box-binding protein gene tbp in multiple bdelloid species suggested that for each gene, each copy belonged to one of two lineages that began to diverge before the bdelloid radiation. Such gene trees are consistent with the two lineages having descended from former alleles that began to diverge after meiotic segregation ceased or from subgenomes of an alloploid ancestor of the bdelloids. However, the original analyses of bdelloid gene-copy divergence used only a single outgroup species and were based on parsimony and neighbor joining. We have now used maximum likelihood and Bayesian inference methods and, for hsp82, multiple outgroups in an attempt to produce more robust gene trees. Here we report that the available data do not unambiguously discriminate between gene trees that root the origin of hsp82 and tbp copy divergence before the bdelloid radiation and those which indicate that the gene copies began to diverge within bdelloid families. The remarkable presence of multiple diverged gene copies in individual genomes is nevertheless consistent with the loss of sex in an ancient ancestor of bdelloids.

Efficient peer-to-peer namespace searches - Gopalakrishnan,V.; Bhattacharjee, Bobby; Chawathe,S.; Keleher,P. (University of Maryland, College Park, MD, Tech. Rep. CSTR-4568, 2004)
In this paper we describe new methods for efficient and exact search (keyword and full-text) in distributed namespaces. Our methods can be used in conjunction with existing distributed lookup schemes, such as Distributed Hash Tables, and distributed directories. We describe how indexes for implementing distributed searches can be efficiently created, located, and stored. We describe techniques for creating approximate indexes that can be used to bound the space requirement at individual hosts; such techniques are particularly useful for full-text searches that may require a very large number of individual indexes to be created and maintained. Our methods use a new distributed data structure called the view tree. View trees can be used to efficiently cache and locate results from prior queries. We describe how view trees are created, and maintained. We present experimental results, using large namespaces and realistic data, showing that the techniques introduced in this paper can reduce search overheads (both network and processing costs) by more than an order of magnitude.

Empirical-based estimation of the effect on software dependability of a technique for architecture conformance verification - Asgari, S.; Basili, Victor R.; Costa,P.; Donzelli,P.; Hochstein, L.; Lindvall,M.; Rus,I.; Shull, F.; Tvedt,R.; Zelkowitz, Marvin V (Proceedings of the ICSE 2004 Workshop on Architecting Dependable Systems, Edinburgh, UK, 2004)
The High Dependability Computing Program (HDCP)project is a NASA initiative for increasing dependability of software-based systems. It researches achieving high dependability by introducing new technologies. We focus on the evaluation of the effectiveness of technologies with respect to dependability. We employ empirical evaluation methods along with evaluation testbeds. In this paper, our technology evaluation approach is described. A testbed representative of air traffic control applications is used. An experiment to evaluate a technology to for identification of architectural violations is presented.

Extending the utility of treemaps with flexible hierarchy - Chintalapani,G.; Plaisant, Catherine; Shneiderman, Ben (Eighth International Conference on Information Visualisation, 2004. IV 2004. Proceedings, 2004)
Treemaps are a visualization technique for presenting hierarchical information on two-dimensional displays. Prior implementations limit the visualization to pre-defined static hierarchies. Flexible hierarchy, a new capability of Treemap 4.0, enables users to define various hierarchies through dynamically selecting a series of data attributes so that they can discover patterns, clusters and outliers. This work describes the design and implementation issues of flexible hierarchy. It then reports on a usability study, which led to enhancements to the interface.
Keywords: 2D displays; Computer displays; Computer science; data visualisation; Data visualization; Educational institutions; flexible hierarchy; graphical user interface; Graphical user interfaces; hierarchical information; Nominations and elections; Switches; Tree data structures; Tree graphs; Treemap 4.0; Two dimensional displays; usability; visualization technique

Facial similarity across age, disguise, illumination and pose - Ramanathan,N.; Chellapa, Rama; Roy Chowdhury, A.K. (Image Processing, 2004. ICIP '04. 2004 International Conference on, 2004)
Illumination, pose variations, disguises, aging effects and expression variations are some of the key factors that affect the performance of face recognition systems. Face recognition systems have always been studied from a recognition perspective. Our emphasis is on deriving a measure of similarity between faces. The similarity measure provides insights into the role each of the above mentioned variations play in affecting the performance of face recognition systems. In the process of computing the similarity measure between faces, we suggest a framework to compensate for pose variations and introduce the notion of 'half-faces' to circumvent the problem of non-uniform illumination. We used the similarity measure to retrieve similar faces from a database containing multiple images of individuals. Moreover, we devised experiments to study the effect age plays in affecting facial similarity. In conclusion, the similarity measure helps in studying the significance facial features play in affecting the performance of face recognition systems.
Keywords: Aging; database; databases; disguise; effect; Expression; Face; half-face; illumination; image; lighting; pose; recognition; recognition; retrieval; system; variation; visual

Ferret: a host vulnerability checking tool - Sharma,Anil; Martin,J.R.; Anand,N.; Michel Cukier; Sanders,W. H. (2004)
Evaluation of computing system security requires knowledge of the vulnerabilities present in the system and of potential attacks against the system. Vulnerabilities can be classified based on their location as application vulnerabilities, network vulnerabilities, or host vulnerabilities. We describe Ferret, a new software tool for checking host vulnerabilities. Ferret helps system administrators by quickly finding vulnerabilities that are present on a host. It is designed and implemented in a modular way: a different plug-in module is used for each vulnerability checked, and each possible output format is specified by a plug-in module. As a result, Ferret is extensible, and can easily be kept up-to-date through addition of checks for new vulnerabilities as they are discovered; the modular approach also makes it easy to provide specific configurations of Ferret tailored to specific operating systems or use environments. Ferret is a freely available open-source software implemented in Perl.
Keywords: Ferret software tool; host vulnerability checking tool; open-source software; Perl; plug-in module; program verification; security auditing tool; security evaluation; security of data; software tools

Few amino acid positions in ıt rpoB are associated with most of the rifampin resistance in ıt Mycobacterium tuberculosis - Cummings, Michael P.; Segal,M. R (BMC Bioinformatics, 2004)
BACKGROUND: Mutations in rpoB, the gene encoding the beta subunit of DNA-dependent RNA polymerase, are associated with rifampin resistance in Mycobacterium tuberculosis. Several studies have been conducted where minimum inhibitory concentration (MIC, which is defined as the minimum concentration of the antibiotic in a given culture medium below which bacterial growth is not inhibited) of rifampin has been measured and partial DNA sequences have been determined for rpoB in different isolates of M. tuberculosis. However, no model has been constructed to predict rifampin resistance based on sequence information alone. Such a model might provide the basis for quantifying rifampin resistance status based exclusively on DNA sequence data and thus eliminate the requirements for time consuming culturing and antibiotic testing of clinical isolates. RESULTS: Sequence data for amino acid positions 511-533 of rpoB and associated MIC of rifampin for different isolates of M. tuberculosis were taken from studies examining rifampin resistance in clinical samples from New York City and throughout Japan. We used tree-based statistical methods and random forests to generate models of the relationships between rpoB amino acid sequence and rifampin resistance. The proportion of variance explained by a relatively simple tree-based cross-validated regression model involving two amino acid positions (526 and 531) is 0.679. The first partition in the data, based on position 531, results in groups that differ one hundredfold in mean MIC (1.596 micrograms/ml and 159.676 micrograms/ml). The subsequent partition based on position 526, the most variable in this region, results in a > 354-fold difference in MIC. When considered as a classification problem (susceptible or resistant), a cross-validated tree-based model correctly classified most (0.884) of the observations and was very similar to the regression model. Random forest analysis of the MIC data as a continuous variable, a regression problem, produced a model that explained 0.861 of the variance. The random forest analysis of the MIC data as discrete classes produced a model that correctly classified 0.942 of the observations with sensitivity of 0.958 and specificity of 0.885. CONCLUSIONS: Highly accurate regression and classification models of rifampin resistance can be made based on this short sequence region. Models may be better with improved (and consistent) measurements of MIC and more sequence data.

Finding governmental statistical data on the Web: A study of categorically organized links for the FedStats topics page - Ceaparu,Irina; Shneiderman, Ben (Journal of the American Society for Information Science and Technology, 2004)
More than 100 U.S. governmental agencies offer links through FedStats, a centralized Web site that facilitates access to statistical tables, reports, and agencies. This and similar large collections need appropriate interfaces to guide the general public to easily and successfully find information they seek. This paper summarizes the results of 3 empirical studies of alternate organization concepts of the FedStats Topics Web page. Each study had 15 participants. The evolution from 645 alphabetically organized links, to 549 categorically organized links, to 215 categorically organized links tied to portal pages produced a steady rise in successful task completion from 15.6 to 24.4 to 42.2%. User satisfaction also increased. We make recommendations based on these data and our observations of users.

Finding Governmental Statistical Data on the Web: Three Empirical Studies of the FedStats Topics Page - Ceaparu,Irina; Shneiderman, Ben (Journal of the American Society for Information Science and Technology, 2004)
Governmental agencies provide statistical data on their web sites. These large collections of data need appropriate interfaces that would guide the general public, as well as the researchers, to easily and successfully find information they seek. This paper summarizes the results of three empirical studies with 15 users in each group of the FedStats Topics web page. The evolution from 645 alphabetically organized links, to 549 categorically organized links, to 215 categorically organized links tied to portal pages produced a steady rise in successful task completion from 15 % to 28 % to 42%. User satisfaction also increased. We make recommendations based on these data and our observations of users.

Formal Modeling Of Middleware-based Distributed Systems - Ray,Arnab; Cleaveland, Rance (Electronic Notes in Theoretical Computer Science, 2004)
Effective design of middleware-based systems requires modeling notations that allow the use of process-interaction schemes provided by different middleware packages directly in designs. Traditional design notations typically only support a fixed class of interprocess interaction schemes, and designers wishing to use them for modeling middleware-based systems must devote significant effort to encoding the middleware primitives in the notation. In this paper, we demonstrate how a new graphical design notation, Architectural Interaction Diagrams (AIDs), which provides parameterized support for different interaction schemes, may be used to model a real-life middleware-based system like the Event Heap coordination infrastructure of the i-Room ubiquitous computing environment.
Keywords: distributed systems; Formal Methods; Middleware; Software architecture

Free-Living to Freewheeling: The Evolution of Vibrio cholerae from Innocence to Infamy - Rita R Colwell; Faruque,S. M.; Nair,G. B. (Infectious Disease and Host-Pathogen EvolutionInfectious Disease and Host-Pathogen Evolution, 2004)

Fusion of gait and face for human identification - Kale, A.; Roy Chowdhury, A.K.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, 2004)
Identification of humans from arbitrary view points is an important requirement for different tasks including perceptual interfaces for intelligent environments, covert security and access control etc. For optimal performance, the system must use as many cues as possible and combine them in meaningful ways. In this paper, we discuss fusion of face and gait cues for the single camera case. We present a view invariant gait recognition algorithm for gait recognition. We employ decision fusion to combine the results of our gait recognition algorithm and a face recognition algorithm based on sequential importance sampling. We consider two fusion scenarios: hierarchical and holistic. The first involves using the gait recognition algorithm as a filter to pass on a smaller set of candidates to the face recognition algorithm. The second involves combining the similarity scores obtained individually from the face and gait recognition algorithms. Simple rules like the SUM, MIN and PRODUCT are used for combining the scores. The results of fusion experiments are demonstrated on the NIST database which has outdoor gait and face data of 30 subjects.
Keywords: access; algorithm; analysis; combining; control; covert; cues; data; decision; Environment; Face; fusion; Gait; hierarchical; holistic; human; identification; importance; intelligent; interfaces; invariant; perceptual; recognition; recognition; rules; sampling; score; scores; security; sensor; sequential; similarity; view

Gait recognition using image self-similarity - BenAbdelkader,Chiraz; Cutler,Ross G.; Davis, Larry S. (EURASIP J. Appl. Signal Process., 2004)
Gait is one of the few biometrics that can be measured at a distance, and is hence useful for passive surveillance as well as biometric applications. Gait recognition research is still at its infancy, however, and we have yet to solve the fundamental issue of finding gait features which at once have suffcient discrimination power and can be extracted robustly and accurately from low-resolution video. This paper describes a novel gait recognition technique based on the image self-similarity of a walking person. We contend that the similarity plot encodes a projection of gait dynamics. It is also correspondence-free, robust to segmentation noise, and works well with low-resolution video. The method is tested on multiple data sets of varying sizes and degrees of diffculty. Performance is best for fronto-parallel viewpoints, whereby a recognition rate of 98% is achieved for a data set of 6 people, and 70% for a data set of 54 people.
Keywords: behavioral biometrics; gait recognition; human identification at a distance; human movement analysis; pattern recognition

Gait-based human identification from a monocular video sequence - Kale, A.; Sundaresan, A.; Roy Chowdhury, A.K.; Chellapa, Rama (Handbook on Pattern Recognition and Computer Vision, 2004)
Human gait is a spatio-temporal phenomenon that characterizes the motion char-acteristics of an individual. It is possible to detect and measure gait even in low- resolution video. In this chapter, we discuss algorithms for identifying people by their gait from a monocular video sequence. Human identification using gait, sim- ilar to text-based speaker identification, involves different individuals performing the same task and a template-matching approach is suitable for such problems. In situations where the amount of training data is limited, we demonstrate the utility of a simple width feature for gait recognition. By virtue of their determin- istic nature, template matching methods have limited noise resilience. In order to deal with noise we introduce a systematic approach to gait recognition by building representations for the structural and dynamic components of gait using exemplars and hidden Markov models (HMMs). The above methods assume that an exact side-view of the subject is available in the probe sequence. For the case when the person walks at an arbitrary angle far away from the camera we present a view invariant gait recognition algorithm which is based on synthesizing a side view of a person from an arbitrary monocular view.

Generalized photometric stereo and its application to face recognition - Zhou, S.; Chellapa, Rama; Jacobs, David W. (International Journal of Computer Vision, 2004)
Most photometric stereo algorithms employ a Lambertian reflectance model witha varying albedo field and involve the appearances of only one object. The recovered albedos and surface normals are object-specific and appearances not belonging to the object cannot be easily handled. We generalize photometric stereo algorithms to handle all appearances of all objects in a class, in particular the human face class, by assuming that albedos and surface normals of all objects in the class be rank-constrained, i.e. lie in a subspace. Rank constraints lead us to a factorization of an observation matrix that consists of exemplar images of different objects under different illuminations. To fully recover the subspace bases or class- specific albedos and surface normals, we employ integrability and face symmetry constraints and propose a linearized algorithm. This algorithm takes into account the effects of the varying albedo field by approximating the integrability terms using only the surface normals. We then apply our generalized photometric stereo algorithm for recognizing faces under illumination variations. As far as recognition is concerned, we can utilize a bootstrap set which is just a collection of 2D image observations to avoid an explicit requirement that 3D information be available. We obtain good recognition results using the PIE database.

A global-state-triggered fault injector for distributed system evaluation - Chandra,Ramesh; Lefever,R.M.; Joshi,K.R.; Michel Cukier; Sanders,W. H. (Parallel and Distributed Systems, IEEE Transactions on, 2004)
Validation of the dependability of distributed systems via fault injection is gaining importance because distributed systems are being increasingly used in environments with high dependability requirements. The fact that distributed systems can fail in subtle ways that depend on the state of multiple parts of the system suggests that a global-state-based fault injection mechanism should be used to validate them. However, global-state-based fault injection is challenging since it is very difficult in practice to maintain the global state of a distributed system at runtime with minimal intrusion into the system execution. We present Loki, a global-state-based fault injector, which has been designed with the goals of low intrusion, high precision, and high flexibility. Loki achieves these goals by utilizing the ideas of partial view of global state, optimistic synchronization, and offline analysis. In Loki, faults are injected based on a partial, view of the global state of the system, and a post-runtime analysis is performed to place events and injections into a single global timeline and to discard experiments with incorrect fault injections. Finally, the experiments with correct fault injections are used to estimate user-specified performance and dependability measures. A flexible measure language has been designed that facilitates the specification of a wide range of measures.
Keywords: distributed processing; distributed system evaluation; fault tolerant computing; global-state-based fault injection mechanism; Loki; offline clock synchronization; performance evaluation; post-runtime analysis; Synchronisation; system recovery; user-specified performance

A hybrid algorithm for subpixel detection in hyperspectral imagery - Broadwater, J.; Meth, R.; Chellapa, Rama (Geoscience and Remote Sensing Symposium, 2004. IGARSS '04. Proceedings. 2004 IEEE International, 2004)
Numerous subpixel detection algorithms utilizing structured backgrounds have been developed over the past few years. These range from detection schemes based on spectral unmixing to generalized likelihood ratio tests. Spectral unmixing algorithms such as the Fully Constrained Least Squares (FCLS) algorithm have the advantage of physically modeling the interactions of spectral signatures based on reflectance/emittance spectroscopy. Generalized likelihood ratio tests like the Adaptive Matched Subspace Detector (AMSD) have the advantage of identifying targets that are statistically different from the background. Therefore, a hybrid detector based on both AMSD and FCLS was developed to take advantage of each detector's strengths. Results demonstrate that the hybrid detector achieved the lowest false alarm rates while also producing meaningful abundance estimates
Keywords: alarm; algorithm; abundance; algorithm; Fully; algorithm; hybrid; algorithm; statistical; AMSD; Adaptive; analysis; structured; approximations; maximum; backgrounds; subpixel; constrained; detection; alarm; detection; target; Detector; FCLS; detector; hyperspectral; estimation; estimation; emittance; identification; adaptive; imagery; reflectance; least; likelihood; Matched; matching; least; processing; geophysical; rate; generalized; ratio; signal; signatures; spectral; spectra; false; spectra; spectral; squares; subspace; systems; geophysical; techniques; image; tests; hybrid; unmixing

Identification of humans using gait - Kale, A.; Sundaresan, A.; Rajagopalan, AN; Cuntoor, N.P.; Roy-Chowdhury, A.K.; Kruger, V.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2004)
We propose a view-based approach to recognize humans from their gait. Two different image features have been considered: the width of the outer contour of the binarized silhouette of the walking person and the entire binary silhouette itself. To obtain the observation vector from the image features, we employ two different methods. In the first method, referred to as the indirect approach, the high-dimensional image feature is transformed to a lower dimensional space by generating what we call the frame to exemplar (FED) distance. The FED vector captures both structural and dynamic traits of each individual. For compact and effective gait representation and recognition, the gait information in the FED vector sequences is captured in a hidden Markov model (HMM). In the second method, referred to as the direct approach, we work with the feature vector directly (as opposed to computing the FED) and train an HMM. We estimate the HMM parameters (specifically the observation probability B) based on the distance between the exemplars and the image features. In this way, we avoid learning high-dimensional probability density functions. The statistical nature of the HMM lends overall robustness to representation and recognition. The performance of the methods is illustrated using several databases.
Keywords: Automated; Reproducibility of Results; Sensitivity and Specificity; Signal Processing; binary silhouette; frame to exemplar distance; gait databases; gait recognition; hidden Markov model; human identification; image features; observation probability; observation vector; hidden Markov models; image recognition; image representation; image sequences; pro; Biological; Models; Computer-Assisted; Models; Computer-Assisted; Subtraction Technique; Task Performance and Analysis; Video Recording; Statistical; Pattern Recognition

Identifying similar parts for assisting cost estimation of prismatic machined parts - Cardone, Antonio; Gupta,S.K.; Karnik,M. (ASME Design for Manufacturing Conference, Salt Lake City, Utah, 2004)

Illuminating light field: image-based face recognition across illuminations and poses - Zhou,Shaohua; Chellapa, Rama (Automatic Face and Gesture Recognition, 2004. Proceedings. Sixth IEEE International Conference on, 2004)
We present an image-based method for face recognition across different illuminations and different poses, where the term 'image-based' means that only 2D images are used and no explicit 3D models are needed. As face recognition across illuminations and poses involves three factors, namely identity, illumination, and pose, generalizations from known identities to novel identities, from known illuminations to novel illuminations, and from known poses to unknown poses are desired. Our approach, called the illuminating light field, derives an identity signature that is invariant to illuminations and poses, where a subspace encoding is assumed for the identity, a Lambertain reflectance model for the illumination, and a light field model for the poses. Experimental results using the PIE database demonstrate the effectiveness of the proposed approach.
Keywords: Face; field; illuminating; image-based; Lambertain; light; lighting; model; multidimensional; poses; processing; recognition; reflectance; reflectivity; signal

Illumination, Reflectance, and Reflection-Characterization of Human Faces under Illumination Variations Using Rank, Integrability, and Symmetry Constraints - Zhou,S. K; Chellapa, Rama; Jacobs, David W. (Lecture Notes in Computer Science, 2004)

Improved Multiuser Detectors Employing Genetic Algorithms in a Space-Time Block Coded System, Yinggang Du and Kam Tai Chan - Self-Similarity,G.R.U.I.; BenAbdelkader,C.; Cutler,R.G.; Davis, Larry S.; Local,F.R.U.; Global Features,J.H.; Yuen, P.C.; Lai,JH; Li,C. (Signal, 2004)

Incremental density approximation and kernel-based bayesian filtering for object tracking - Han,B.; Comaniciu, D.; Zhu,Y.; Davis, Larry S. (IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004)
Statistical density estimation techniques are used in manycomputer vision applications such as object tracking, back- ground subtraction, motion estimation and segmentation. The particle filter (Condensation) algorithm provides a gen- eral framework for estimating the probability density func- tions (pdf) of general non-linear and non-Gaussian systems. However, since this algorithm is based on a Monte Carlo ap- proach, where the density is represented by a set of random samples, the number of samples is problematic, especially for high dimensional problems. In this paper, we propose an alternative to the classical particle filter in which the un- derlying pdf is represented with a semi-parametric method based on a mode finding algorithm using mean-shift. A mode propagation technique is designed for this new representa- tion for tracking applications. A quasi-random sampling method [14] in the measurement stage is used to improve performance, and sequential density approximation for the measurements distribution is performed for efficient compu- tation. We apply our algorithm to a high dimensional color- based tracking problem, and demonstrate its performance by showing competitive results with other trackers.

Infectious disease and environment: cholera as a paradigm for waterborne disease - Rita R Colwell (International Microbiology, 2004)

An information theoretic criterion for evaluating the quality of 3-D reconstructions from video - Roy-Chowdhury, A.K.; Chellapa, Rama (Image Processing, IEEE Transactions on, 2004)
Even though numerous algorithms exist for estimating the three-dimensional (3-D) structure of a scene from its video, the solutions obtained are often of unacceptable quality. To overcome some of the deficiencies, many application systems rely on processing more data than necessary, thus raising the question: how is the accuracy of the solution related to the amount of data processed by the algorithm? Can we automatically recognize situations where the quality of the data is so bad that even a large number of additional observations will not yield the desired solution? Previous efforts to answer this question have used statistical measures like second order moments. They are useful if the estimate of the structure is unbiased and the higher order statistical effects are negligible, which is often not the case. This paper introduces an alternative information-theoretic criterion for evaluating the quality of a 3-D reconstruction. The accuracy of the reconstruction is judged by considering the change in mutual information (MI) (termed as the incremental MI) between a scene and its reconstructions. An example of 3-D reconstruction from a video sequence using optical flow equations and known noise distribution is considered and it is shown how the MI can be computed from first principles. We present simulations on both synthetic and real data to demonstrate the effectiveness of the proposed criterion.
Keywords: 3D reconstruction; algorithms; Artificial intelligence; Automated; Reproducibility of Results; Sensitivity and Specificity; Signal Processing; Computer Graphics; Computer-Assisted; Imaging; Computer-Assisted; Software Validation; Subtraction Technique; Video Recording; Image Enhancement; Image Interpretation; Image reconstruction; Image sequences; information theoretic criterion; Mutual information; NOISE; noise distribution; optical flow equations; second order moments; statistical analysis; Three-Dimensional; Information Storage and Retrieval; Information Theory; Movement; Pattern Recognition; Video sequences; video signal processing

Interactively Optimizing Signal-to-Noise Ratios in Expression Profiling: Project-Specific Algorithm Selection and Detection P-Value Weighting in Affymetrix Microarrays - Seo,Jinwook; Bakay,Marina; Chen,Yi-Wen; Hilmer,Sara; Shneiderman, Ben; Hoffman,Eric P (BioinformaticsBioinformatics, 2004)
Motivation: The most commonly utilized microarrays for mRNA profiling (Affymetrix) include ‘probe sets’ of a series of perfect match and mismatch probes (typically 22 oligonucleotides per probe set). There are an increasing number of reported ‘probe set algorithms’ that differ in their interpretation of a probe set to derive a single normalized ‘signal’ representative of expression of each mRNA. These algorithms are known to differ in accuracy and sensitivity, and optimization has been done using a small set of standardized control microarray data. We hypothesized that different mRNA profiling projects have varying sources and degrees of confounding noise, and that these should alter the choice of a specific probe set algorithm. Also, we hypothesized that use of the Microarray Suite (MAS) 5.0 probe set detection p-value as a weighting function would improve the performance of all probe set algorithms.Results: We built an interactive visual analysis software tool (HCE2W) to test and define parameters in Affymetrix analyses that optimize the ratio of signal (desired biological variable) versus noise (confounding uncontrolled variables). Five probe set algorithms were studied with and without statistical weighting of probe sets using the MAS 5.0 probe set detection p-values. The signal-to-noise ratio optimization method was tested in two large novel microarray datasets with different levels of confounding noise, a 105 sample U133A human muscle biopsy dataset (11 groups: mutation-defined, extensive noise), and a 40 sample U74A inbred mouse lung dataset (8 groups: little noise). Performance was measured by the ability of the specific probe set algorithm, with and without detection p-value weighting, to cluster samples into the appropriate biological groups (unsupervised agglomerative clustering with F-measure values). Of the total random sampling analyses, 50% showed a highly statistically significant difference between probe set algorithms by ANOVA [F(4,10) > 14, p < 0.0001], with weighting by MAS 5.0 detection p-value showing significance in the mouse data by ANOVA [F(1,10) > 9, p < 0.013] and paired t-test [t(9) = −3.675, p = 0.005]. Probe set detection p-value weighting had the greatest positive effect on performance of dChip difference model, ProbeProfiler and RMA algorithms. Importantly, probe set algorithms did indeed perform differently depending on the specific project, most probably due to the degree of confounding noise. Our data indicate that significantly improved data analysis of mRNA profile projects can be achieved by optimizing the choice of probe set algorithm with the noise levels intrinsic to a project, with dChip difference model with MAS 5.0 detection p-value continuous weighting showing the best overall performance in both projects. Furthermore, both existing and newly developed probe set algorithms should incorporate a detection p-value weighting to improve performance. Availability: The Hierarchical Clustering Explorer 2.0 is available at http://www.cs.umd.edu/hcil/hce/. Murine arrays (40 samples) are publicly available at the PEPR resource (http://microarray.cnmcresearch.org/pgadatatable.asp; http://pepr.cnmcresearch.org; Chen et al., 2004).

Intra-personal kernel space for face recognition - Zhou,Shaohua; Chellapa, Rama; Moghaddam, B. (Automatic Face and Gesture Recognition, 2004. Proceedings. Sixth IEEE International Conference on, 2004)
Intra-personal space modeling proposed by Moghaddam et al. has been successfully applied in face recognition. In their work the regular principal subspaces are derived from the intra-personal spacce using a principal componen analysis and embedded in a probabilistic formulation. In this paper, we derive the principal subspace from the intro-personal kernel space by developing a probabilistic analysis for kernel principal components for face recognition. We test this algorithm on a subset of the FERET database with illumination and facial expression variations. The recognition performance demonstrates its advantage over other traditional subspace approaches.
Keywords: analysis; component; Expression; Face; facial; illumination; intra-personal; Kernel; lighting; principal; probabilistic; probability; recognition; space; variation

Kullback-Leibler distance between two Gaussian densities in reproducing kernel Hilbert space - Zhou,S. K; Chellapa, Rama (IEEE Intl. Symp. Information Theory, 2004)

Left-Brain/Right-Brain Multi-Document Summarization - Conroy,John M.; Schlesinger,Judith D.; Goldstein,Jade; O'Leary, Dianne P. (DUC 04 Conference ProceedingsDUC 04 Conference Proceedings, 2004)

Mandarin-English Information (MEI): investigating translingual speech retrieval - Meng,Helen M.; Chen,Berlin; Khudanpur,Sanjeev; Levow,Gina-Anne; Lo,Wai-Kit; Oard, Douglas; Schone,Patrick; Tang,Karen; Wang,Hsin-Min; Wang,Jianqiang (Computer Speech & Language, 2004)
This paper describes the Mandarin–English Information (MEI) project, where we investigated the problem of cross-language spoken document retrieval (CL-SDR), and developed one of the first English–Chinese CL-SDR systems. Our system accepts an entire English news story (text) as query, and retrieves relevant Chinese broadcast news stories (audio) from the document collection. Hence, this is a cross-language and cross-media retrieval task. We applied a multi-scale approach to our problem, which unifies the use of phrases, words and subwords in retrieval. The English queries are translated into Chinese by means of a dictionary-based approach, where we have integrated phrase-based translation with word-by-word translation. Untranslatable named entities are transliterated by a novel subword translation technique. The multi-scale approach can be divided into three subtasks – multi-scale query formulation, multi-scale audio indexing (by speech recognition) and multi-scale retrieval. Experimental results demonstrate that the use of phrase-based translation and subword translation gave performance gains, and multi-scale retrieval outperforms word-based retrieval.
Keywords: English–Chinese cross-language spoken document retrieval; Multi-scale spoken document retrieval

Mixing ideas: a new technique for working with young children as design partners - Guha,M.L.; Druin, Allison; Chipman,G.; Fails,J. A; Simms,S.; Farber,A. (Proceedings of the 2004 conference on Interaction design and children: building a community, 2004)

Multiple view tracking of humans modelled by kinematic chains - Sundaresan, A.; Chellapa, Rama; RoyChowdhury, R. (Image Processing, 2004. ICIP '04. 2004 International Conference on, 2004)
We use a kinematic chain to model human body motion. We estimate the kinematic chain motion parameters using pixel displacements calculated from video sequences obtained from multiple calibrated cameras to perform tracking. We derive a linear relation between the 2D motion of pixels in terms of the 3D motion parameters of various body parts using a perspective projection model for the cameras, a rigid body motion model for the base body and the kinematic chain model for the body parts. An error analysis of the estimator is provided, leading to an iterative algorithm for calculating the motion parameters from the pixel displacements. We provide experimental results to demonstrate the accuracy of our formulation. We also compare our iterative algorithm to the noniterative algorithm and discuss its robustness in the presence of noise.
Keywords: 3D; algorithm; analysis; body; calibrated; cameras; chain; displacement; error; estimation; human; image; iterative; kinematic; kinematics; methods; model; MOTION; motion; multiple; parameters; perspective; Pixel; processing; projection; sequences; signal; tracking; video; view

Multiple-exemplar discriminant analysis for face recognition - Zhou,S. K; Chellapa, Rama (Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on, 2004)
Face recognition is characteristically different from regular pattern recognition and, therefore, requires a different discriminant analysis other than linear discriminant analysis(LDA). LDA is a single-exemplar method in the sense that each class during classification is represented by a single exemplar, i.e., the sample mean of the class. We present a multiple-exemplar discriminant analysis (MEDA) where each class is represented using several exemplars or even the whole available sample set. The proposed approach produces improved classification results when tested on a subset of FERET database where LDA is ineffective.
Keywords: analysis; database; databases; discriminant; Face; FERET; multiple-exemplar; recognition; visual

Multi-resolution modeling, visualization and streaming of volume meshes - Cignoni,P.; De Floriani, Leila; Lindstrom,P.; Pascucci,V.; Rossignac,J.; Silva,C. (Eurographics 2004, Tutorials 2: Multi-resolution Modeling, Visualization and Streaming of Volume Meshes, 2004)

New directions in design for manufacturing - Herrmann,J.W.; Cooper,J.; Gupta,S.K.; Hayes,C. C.; Ishii,K.; Kazmer,D.; Sandborn,P. A.; Wood,W. H. (2004)
This paper gives an overview of research that is expandingthe domain of design for manufacturing (DFM) into new and important areas. This paper covers DFM and concurrent engineering, DFM for conceptual design, DFM for embodiment design, DFM for detailed design, design for production, platform design for reducing time-to-market, design for system quality, design for life cycle costs, and design for environment. The paper concludes with some general guidelines that suggest how manufacturing firms can develop useful, effective DFM tools.

Oasys: An opinion analysis system - Cesarano,C.; Dorr, Bonnie J; Picariello, A.; Reforgiato,D.; Sagoff,A.; V.S. Subrahmanian (AAAI Spring symposium on Computational Approaches to Analyzing Weblogs, 2004)
There are numerous applications in which we would like toassess what opinions are being expressed in text documents. For 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.

Occurrence and distribution of Vibrio cholerae in the coastal environment of Peru - Gil,Ana I.; Louis,Valérie R.; Rivera,Irma N. G.; Lipp,Erin; Huq,Anwar; Lanata,Claudio F.; Taylor,David N.; Russek‐Cohen,Estelle; Choopun,Nipa; Sack,R. Bradley; Rita R Colwell (Environmental Microbiology, 2004)
The occurrence and distribution of Vibrio cholerae in sea water and plankton along the coast of Peru were studied from October 1997 to June 2000, and included the 1997–98 El Niño event. Samples were collected at four sites in coastal waters off Peru at monthly intervals. Of 178 samples collected and tested, V. cholerae O1 was cultured from 10 (5.6%) samples, and V. cholerae O1 was detected by direct fluorescent antibody assay in 26 out of 159 samples tested (16.4%). Based on the number of cholera cases reported in Peru from 1997 to 2000, a significant correlation was observed between cholera incidence and elevated sea surface temperature (SST) along the coast of Peru (P < 0.001). From the results of this study, coastal sea water and zooplankton are concluded to be a reservoir for V. cholerae in Peru. The climate–cholera relationship observed for the 1997–98 El Niño year suggests that an early warning system for cholera risk can be established for Peru and neighbouring Latin American countries.

Pandemic strains of O3:K6 Vibrio parahaemolyticus in the aquatic environment of Bangladesh - Islam,M. S.; Tasmin,Rizwana; Khan,Sirajul I. s l a m; Bakht,Habibul B. M.; Mahmood,Zahid H. a y a t; Rahman,M. Z. i a u r; Bhuiyan,Nurul A. m i n; Nishibuchi,Mitsuaki; Nair,G. B. a l a k r i s h; Sack,R. B. r a d l e y; Huq,Anwar; Rita R Colwell; et al. (Canadian Journal of Microbiology, 2004)
A total of 1500 environmental strains of Vibrio parahaemolyticus, isolated from the aquatic environment of Bangladesh, were screened for the presence of a major V. parahaemolyticus virulence factor, the thermostable direct haemolysin (tdh) gene, by the colony blot hybridization method using a digoxigenin-labeled tdh gene probe. Of 1500 strains, 5 carried the tdh sequence, which was further confirmed by PCR using primers specific for the tdh gene. Examination by PCR confirmed that the 5 strains were V. parahamolyticus and lacked the thermostable direct haemolysin-related haemolysin (trh) gene, the alternative major virulence gene known to be absent in pandemic strains. All 5 strains gave positive Kanagawa phenomenon reaction with characteristic beta-haemolysis on Wagatsuma agar medium. Southern blot analysis of the HindIII-digested chromosomal DNA demonstrated, in all 5 strains, the presence of 2 tdh genes common to strains positive for Kanagawa phenomenon. However, the 5 strains were found to belong to 3 different serotypes (O3:K29, O4:K37, and O3:K6). The 2 with pandemic serotype O3:K6 gave positive results in group-specific PCR and ORF8 PCR assays, characteristics unique to the pandemic clone. Clonal variations among the 5 isolates were analyzed by comparing RAPD and ribotyping patterns. Results showed different patterns for the 3 serotypes, but the pattern was identical among the O3:K6 strains. This is the first report on the isolation of pandemic O3:K6 strains of V. parahaemolyticus from the aquatic environment of Bangladesh.

Polylysogeny and prophage induction by secondary infection in Vibrio cholerae - Espeland,Eric M.; Lipp,Erin K.; Huq,Anwar; Rita R Colwell (Environmental Microbiology, 2004)
Strains of Vibrio cholerae O1, biotypes El Tor and classical, were infected with a known temperate phage (ΦP15) and monitored over a 15-day period for prophage induction. Over the course of the experiment two morphologically and three genomically distinct virus-like particles were observed from the phage-infected El Tor strain by transmission electron microscopy and field inversion gel electrophoresis, respectively, whereas only one phage, ΦP15, was observed from the infected classical strain. In the uninfected El Tor culture one prophage was spontaneously induced after 6 days. No induction in either strain was observed after treatment with mitomycin C. Data indicate that El Tor biotypes of V. cholerae may be polylysogenic and that secondary infection can promote multiple prophage induction. These traits may be important in the transfer of genetic material among V. cholerae by providing an environmentally relevant route for multiple prophage propagation and transmission.

Pose-normailzed view synthesis of a symmetric object using a single image - Yue, Z.; Chellapa, Rama (Proceedings of the 6th Asian Conference on Computer Vision (ACCV'04), 2004)
Object recognition under varying pose is a challenging prob-lem, especially when illumination variations are also present. In this paper, we propose a pose-normalized view synthe- sis method under varying illuminations for symmetric ob- jects. For a given non-frontal view of a symmetric object under non-frontal illumination, the mirror image of the orig- inal view is equivalent to the view when the object rotates around the Y -axis by the same angle as the original view but in the opposite direction, and under opposite illumina- tion condition in the X direction. Exploiting the bilateral symmetry of the object, we generate the mirror view of the object under the same illumination condition as the original view on a pixel-by-pixel basis. The frontal view under the same illumination is then easily obtained using view mor- phing techniques.

Proactive key distribution using neighbor graphs - Mishra,A.; Min Ho Shin; Petroni,N. L.; Clancy,T. C; Arbaugh, William A. (IEEE Wireless Communications, 2004)
User mobility in wireless data networks is increasing because of technological advances, and the desire for voice and multimedia applications. These applications, however, require that handoffs between base stations (or access points) be fast to maintain the quality of the connections. In this article we introduce a novel data structure, the neighbor graph, that dynamically captures the mobility topology of a wireless network. We show how neighbor graphs can be utilized to obtain a 99 percent reduction in the authentication time of an IEEE 802.11 handoff (full EAP-TLS) by proactively distributing necessary key material one hop ahead of the mobile user. We also present a reactive method for fast authentication that requires only firmware changes to access points and hence can easily be deployed on existing wireless networks.
Keywords: access points; Authentication; authentication time; Base stations; Communication system security; Delay; graph theory; GSM; IEEE 802.11 handoff; Land mobile radio cellular systems; Message authentication; mobile radio; Multiaccess communication; neighbor graph; Network topology; Roaming; telecommunication security; Telephone sets; user mobility; Wi-Fi networks; wireless data networks; Wireless LAN; Wireless networks

Probabilistic analysis of kernel principal components - Zhou, S.; Chellapa, Rama; Moghaddam, B. (NIPS, 2004)
This paper presents a probabilistic analysis of kernel principal compo-nents by unifying the theory of probabilistic principal component analy- sis and kernel principal component analysis. It is shown that, while the kernel component enhances the nonlinear modeling power, the proba- bilistic structure offers (i) a mixture model for nonlinear data structure containing nonlinear sub-structures, and (ii) an effective classification scheme. It turns out that the original loading matrix is replaced by a newly defined empirical loading matrix. The expectation/maximization algorithm for learning parameters of interest is also presented.

Probabilistic identity characterization for face recognition - Zhou,S. K; Chellapa, Rama (Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on, 2004)
We present a general framework for characterizing the object identity in a single image or a group of images with each image containing a transformed version of the object, with applications to face recognition. In terms of the transformation, the group is made of either many still images or frames of a video sequence. The object identity is either discrete- or continuous-valued. This probabilistic framework integrates all the evidence of the set and handles the localization problem, illumination and pose variations through subspace identity encoding. Issues and challenges arising in this framework are addressed and efficient computational schemes are presented. Good face recognition results using the PIE database are reported.
Keywords: characterization; database; database; encoding; Face; identity; identity; image; localization; management; object; PIE; probabilistic; problem; recognition; sequence; sequences; subspace; systems; video

Project portfolio earned value management using treemaps - Cable,J. H; Ordonez,J. F; Chintalapani,G.; Plaisant, Catherine (Proceedings of the Project Management Institute Research Conference, 2004)
Project portfolio management deals with organizing and managing a set of projects in anorganization. Each organization has its own way of managing the portfolio that meets its business goals. One of the main challenges is to track project performance across the entire portfolio in a timely and effective manner. It allows managers to diagnose performance trends and identify projects in need of attention, giving them the opportunity to take management action in a timely fashion. In this paper, we investigate the use of Earned Value Management (EVM) for tracking project performance across the portfolio, and explore the benefits of an interactive visualization technique called Treemaps to display project performance metrics for the entire portfolio on a single screen.

Reconstructing Images of Bar Codes for Construction Site Object Recognition - Gilsinn,David E.; Cheok,Geraldine S.; O'Leary, Dianne P. (Automation in Construction (Elsevier), 2004)

Robust Bayesian cameras motion estimation using random sampling - Qian, G.; Chellapa, Rama; Qinfen Zheng (Image Processing, 2004. ICIP '04. 2004 International Conference on, 2004)
In this paper, we propose an algorithm for robust 3D motion estimation of wide baseline cameras from noisy feature correspondences. The posterior probability density function of the camera motion parameters is represented by weighted samples. The algorithm employs a hierarchy coarse-to-fine strategy. First, a coarse prior distribution of camera motion parameters is estimated using the random sample consensus scheme (RANSAC). Based on this estimate, a refined posterior distribution of camera motion parameters can then be obtained through importance sampling. Experimental results using both synthetic and real image sequences indicate the efficacy of the proposed algorithm.
Keywords: 3D; baseline; Bayesian; CAMERAS; cameras; coarse-to-fine; consensus; density; estimation; feature; function; hierarchy; image; images; importance; matching; MOTION; posterior; probability; probability; processing; random; RANSAC; real; realistic; sample; sampling; scheme; sequences; stereo; strategy; synthetic; wide

Robust ego-motion estimation and 3D model refinement using depth based parallax model - Agrawala, Ashok K.; Chellapa, Rama (Image Processing, 2004. ICIP '04. 2004 International Conference on, 2004)
We present an iterative algorithm for robustly estimating the ego-motion and refining and updating a coarse, noisy and partial depth map using a depth based parallax model and brightness derivatives extracted from an image pair. Given a coarse, noisy and partial depth map acquired by a range-finder or obtained from a Digital Elevation Map (DFM), we first estimate the ego-motion by combining a global ego-motion constraint and a local brightness constancy constraint. Using the estimated camera motion and the available depth map estimate, motion of the 3D 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. Instead of assuming a smooth parallax field or locally smooth depth models, we locally model the parallax magnitude using the depth map, formulate the problem as a generalized eigen-value analysis and obtain better results. In addition, confidence measures for depth estimates are provided which can be used to remove regions with potentially incorrect (and outliers in) depth estimates for robustly estimating ego-motion in the next iteration. Results on both synthetic and real examples are presented.
Keywords: 3D; algorithm; analysis; and; based; camera; coarse; compensation; DEM; depth; digital; ego-motion; eigen-value; eigenfunctions; eigenvalues; ELEVATION; epipolar; estimation; extraction; feature; field; iteration; iterative; map; method; methods; model; model; MOTION; parallax; partial; range-finding; refinement; refining; surface

Robust two-camera tracking using homography - Yue,Zhanfeng; Zhou,S. K; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, 2004)
The paper introduces a two view tracking method which uses the homography relation between the two views to handle occlusions. An adaptive appearance-based model is incorporated in a particle filter to realize robust visual tracking. Occlusion is detected using robust statistics. When there is occlusion in one view, the homography from this view to other views is estimated from previous tracking results and used to infer the correct transformation for the occluded view. Experimental results show the robustness of the two view tracker.
Keywords: Carlo; filter; filters; frame; framework; homography; image; method; methods; Monte; nonlinear; occlusions; optical; particle; processing; robust; sequences; sequential; signal; statistics; tracking; tracking; two; two-camera; video; view; visual

Role of shape and kinematics in human movement analysis - Veeraraghavan,A.; Chowdhury, A.R.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on, 2004)
Human gait and activity analysis from video is presently attracting a lot of attention in the computer vision community. In this paper we analyze the role of two of the most important cues in human motion-shape and kinematics. We present an experimental framework whereby it is possible to evaluate the relative importance of these two cues in computer vision based recognition algorithms. In the process, we propose a new gait recognition algorithm by computing the distance between two sequences of shapes that lie on a spherical manifold. In our experiments, shape is represented using Kendall's definition of shape. Kinematics is represented using a Linear Dynamical system We place particular emphasis on human gait. Our conclusions show that shape plays a role which is more significant than kinematics in current automated gait based human identification algorithms. As a natural extension we study the role of shape and kinematics in activity recognition. Our experiments indicate that we require models that contain both shape and kinematics in order to perform accurate activity classification. These conclusions also allow us to explain the relative performance of many existing methods in computer-based human activity modeling.
Keywords: activity; algorithm; algorithms; analysis; autoregressive; average; based; classification; community; Computer; definition; dynamical; extraction; feature; Gait; hidden; human; identification; image; Kendall; linear; manifold; Markov; modeling; models; MOTION; Movement; moving; processes; recognition; sequences; SHAPE; spherical; system; VISION; vision

Section-level relationships of North American ıt Agalinis (Orobanchaceae) based on DNA sequence analysis of three chloroplast gene regions - Neel,M. C; Cummings, Michael P. (BMC Evol Biol, 2004)
BACKGROUND: The North American Agalinis are representatives of a taxonomically difficult group that has been subject to extensive taxonomic revision from species level through higher sub-generic designations (e.g., subsections and sections). Previous presentations of relationships have been ambiguous and have not conformed to modern phylogenetic standards (e.g., were not presented as phylogenetic trees). Agalinis contains a large number of putatively rare taxa that have some degree of taxonomic uncertainty. We used DNA sequence data from three chloroplast genes to examine phylogenetic relationships among sections within the genus Agalinis Raf. (=Gerardia), and between Agalinis and closely related genera within Orobanchaceae. RESULTS: Maximum likelihood analysis of sequences data from rbcL, ndhF, and matK gene regions (total aligned length 7323 bp) yielded a phylogenetic tree with high bootstrap values for most branches. Likelihood ratio tests showed that all but a few branch lengths were significantly greater than zero, and an additional likelihood ratio test rejected the molecular clock hypothesis. Comparisons of substitution rates between gene regions based on linear models of pairwise distance estimates between taxa show both ndhF and matK evolve more rapidly than rbcL, although the there is substantial rate heterogeneity within gene regions due in part to rate differences among codon positions. CONCLUSIONS: Phylogenetic analysis supports the monophyly of Agalinis, including species formerly in Tomanthera, and this group is sister to a group formed by the genera Aureolaria, Brachystigma, Dasistoma, and Seymeria. Many of the previously described sections within Agalinis are polyphyletic, although many of the subsections appear to form natural groups. The analysis reveals a single evolutionary event leading to a reduction in chromosome number from n = 14 to n = 13 based on the sister group relationship of section Erectae and section Purpureae subsection Pedunculares. Our results establish the evolutionary distinctiveness of A. tenella from the more widespread and common A. obtusifolia. However, further data are required to clearly resolve the relationship between A. acuta and A. tenella.

Selective refinement queries for volume visualization of unstructured tetrahedral meshes - Cignoni,P.; De Floriani, Leila; Magillo,P.; Puppo,E.; Scopigno,R. (Visualization and Computer Graphics, IEEE Transactions on, 2004)
We address the problem of the efficient visualization of large irregular volume data sets by exploiting a multiresolution model based on tetrahedral meshes. Multiresolution models, also called Level-Of-Detail (LOD) models, allow encoding the whole data set at a virtually continuous range of different resolutions. We have identified a set of queries for extracting meshes at variable resolution from a multiresolution model, based on field values, domain location, or opacity of the transfer function. Such queries allow trading off between resolution and speed in visualization. We define a new compact data structure for encoding a multiresolution tetrahedral mesh built through edge collapses to support selective refinement efficiently and show that such a structure has a storage cost from 3 to 5.5 times lower than standard data structures used for tetrahedral meshes. The data structures and variable resolution queries have been implemented together with state-of-the art visualization techniques in a system for the interactive visualization of three-dimensional scalar fields defined on tetrahedral meshes. Experimental results show that selective refinement queries can support interactive visualization of large data sets.
Keywords: Automated; Signal Processing; Computer-Assisted; Imaging; Computer-Assisted; User-Computer Interface; data structure; geometric modeling; interactive visualization; large data sets; multiresolution model; selective refinement queries; unstructured tetrahedral meshes; variable resolution queries; volume data visualization; data visualisation; mesh generation; query p; Three-Dimensional; Online Systems; Pattern Recognition

A semidefinite programming approach to side chain positioning with new rounding strategies - Chazelle,B.; Kingsford, Carl; Singh,M. (INFORMS Journal on Computing, 2004)

Sequential kernel density approximation through mode propagation: applications to background modeling - Han,B.; Comaniciu, D.; Davis, Larry S. (Proc. ACCV, 2004)
Density-based modeling of visual features is very commonin computer vision, either by using non-parametric techniques or through representing the underlying density function as a weighted sum of Gaussians. A number of real-time tasks such as background modeling or modeling the appearance of a moving target require sequential density estimation, where new data is incorporated in the model as it becomes avail- able. Nevertheless, current methods for updating the den- sity function either lack flexibility, by fixing the number of Gaussians in the mixture, or require large memory amounts, by maintaining a non-parametric representation of the den- sity. This paper presents an efficient method for recursive density approximation that relies on the propagation of the density modes. At each time step, the modes of the density are re-estimated and a Gaussian component is assigned to each mode. The covariance of each component is derived from the Hessian matrix estimated at the mode location. To detect the modes we employ the variable-bandwidth mean shift. While the proposed density representation is mem- ory efficient (which is typical for mixture densities), it in- herits the flexibility of non-parametric methods, by allow- ing the number of modes to adapt in time. We show that the same mode propagation principle applies for subspaces derived from eigen analysis. Extensive experimental back- ground modeling results demonstrate the performance of the method.

SESSION 2: STREAMING - Banerjee,S.; Lee,S.; Braud,R.; Bhattacharjee, Bobby; Srinivasan, Aravind; Chu,Y.; Zhang,H.; Sinha,R.; Papadopoulos,C.; Boustead,P.; others (Proceedings of the 14th International Workshop on Network and Operating Systems Support for Digital Audio and Video: NOSSDAV 2003: June 16-18, 2004, Cork, Ireland, 2004)

Simple statistical models predict C-to-U edited sites in plant mitochondrial RNA - Cummings, Michael P.; Myers,D. S (BMC Bioinformatics, 2004)
BACKGROUND: RNA editing is the process whereby an RNA sequence is modified from the sequence of the corresponding DNA template. In the mitochondria of land plants, some cytidines are converted to uridines before translation. Despite substantial study, the molecular biological mechanism by which C-to-U RNA editing proceeds remains relatively obscure, although several experimental studies have implicated a role for cis-recognition. A highly non-random distribution of nucleotides is observed in the immediate vicinity of edited sites (within 20 nucleotides 5' and 3'), but no precise consensus motif has been identified. RESULTS: Data for analysis were derived from the the complete mitochondrial genomes of Arabidopsis thaliana, Brassica napus, and Oryza sativa; additionally, a combined data set of observations across all three genomes was generated. We selected datasets based on the 20 nucleotides 5' and the 20 nucleotides 3' of edited sites and an equivalently sized and appropriately constructed null-set of non-edited sites. We used tree-based statistical methods and random forests to generate models of C-to-U RNA editing based on the nucleotides surrounding the edited/non-edited sites and on the estimated folding energies of those regions. Tree-based statistical methods based on primary sequence data surrounding edited/non-edited sites and estimates of free energy of folding yield models with optimistic re-substitution-based estimates of approximately 0.71 accuracy, approximately 0.64 sensitivity, and approximately 0.88 specificity. Random forest analysis yielded better models and more exact performance estimates with approximately 0.74 accuracy, approximately 0.72 sensitivity, and approximately 0.81 specificity for the combined observations. CONCLUSIONS: Simple models do moderately well in predicting which cytidines will be edited to uridines, and provide the first quantitative predictive models for RNA edited sites in plant mitochondria. Our analysis shows that the identity of the nucleotide -1 to the edited C and the estimated free energy of folding for a 41 nt region surrounding the edited C are the most important variables that distinguish most edited from non-edited sites. However, the results suggest that primary sequence data and simple free energy of folding calculations alone are insufficient to make highly accurate predictions.

Simultaneous background and foreground modeling for tracking in surveillance video - Shao, J.; Zhou,S. K; Chellapa, Rama (Image Processing, 2004. ICIP '04. 2004 International Conference on, 2004)
We present a stochastic tracking algorithm for surveillance video where targets are dim and at low resolution. The algorithm builds motion models for both background and foreground by integrating motion and intensity information. Some other merits of the algorithm include adaptive selection of feature points for scene description and defining proper cost functions for displacement estimation. The experimental results show tracking robustness and precision in a challenging video sequences.
Keywords: algorithm; analysis; background-foreground; displacement; estimation; image; information; INTENSITY; modeling; MOTION; processes; processing; resolution; sequences; signal; Stochastic; Surveillance; surveillance; tracking; tracking; video

SlideBar: Analysis of a linear input device - Chipman,L.E.; Bederson, Benjamin B.; Golbeck,J. (Behaviour & Information Technology, 2004)

Social and psychological influences on computer user frustration - Bessiere,K.; Ceaparu,I.; Lazar,J.; Robinson,J.; Shneiderman, Ben (Media access: Social and psychological dimensions of new technology useMedia access: Social and psychological dimensions of new technology use, 2004)

Structure from Motion Using Sequential Monte Carlo Methods - Qian,Gang; Chellapa, Rama (International Journal of Computer Vision, 2004)
In this paper, the structure from motion (SfM) problem is addressed using sequential Monte Carlo methods. A new SfM algorithm based on random sampling is derived to estimate the posterior distributions of camera motion and scene structure for the perspective projection camera model. Experimental results show that challenging issues in solving the SfM problem, due to erroneous feature tracking, feature occlusion, motion/structure ambiguity, mixed-domain sequences, mismatched features, and independently moving objects, can be well modeled and effectively addressed using the proposed method.

Studying code development for high performance computing: the HPCS program - Carver, J.; Asgari, S.; Basili, Victor R.; Hochstein, L.; Hollingsworth, Jeffrey K; Shull, F.; Zelkowitz, Marvin V (First International Workshop On Software Engineering for High Performance Computing System Applications, 2004)

A system identification approach for video-based face recognition - Aggarwal,G.; Chowdhury, A.K.R.; Chellapa, Rama (Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on, 2004)
The paper poses video-to-video face recognition as a dynamical system identification and classification problem. We model a moving face as a linear dynamical system whose appearance changes with pose. An autoregressive and moving average (ARMA) model is used to represent such a system. The choice of ARMA model is based on its ability to take care of the change in appearance while modeling the dynamics of pose, expression etc. Recognition is performed using the concept of sub space angles to compute distances between probe and gallery video sequences. The results obtained are very promising given the extent of pose, expression and illumination variation in the video data used for experiments.
Keywords: and; autoregressive; average; dynamical; Face; gallery; identification; image; linear; model; moving; processes; processing; recognition; sequences; signal; system; system; video; video-based

A Tangled Bank: Reflections on the Tree of Life and Human Health - Rita R Colwell (Assembling the Tree of LifeAssembling the Tree of Life, 2004)

Tools for children to create physical interactive storyrooms - Montemayor,J.; Druin, Allison; Chipman,G.; Farber,A.; Guha,M.L. (Computers in Entertainment (CIE), 2004)

Ubistatins Inhibit Proteasome-Dependent Degradation by Binding the Ubiquitin Chain - Verma,Rati; Peters,Noel R.; D'Onofrio,Mariapina; Tochtrop,Gregory P.; Sakamoto,Kathleen M.; Varadan,Ranjani; Zhang,Mingsheng; Coffino,Philip; Fushman, David; Deshaies,Raymond J.; King,Randall W. (Science, 2004)
To identify previously unknown small molecules that inhibit cell cycle machinery, we performed a chemical genetic screen in Xenopus extracts. One class of inhibitors, termed ubistatins, blocked cell cycle progression by inhibiting cyclin B proteolysis and inhibited degradation of ubiquitinated Sic1 by purified proteasomes. Ubistatins blocked the binding of ubiquitinated substrates to the proteasome by targeting the ubiquitin-ubiquitin interface of Lys48-linked chains. The same interface is recognized by ubiquitin-chain receptors of the proteasome, indicating that ubistatins act by disrupting a critical protein-protein interaction in the ubiquitin-proteasome system.

Unit verification: the CARA experience - Ray,A.; Cleaveland, Rance (International Journal on Software Tools for Technology Transfer (STTT), 2004)

Variation of toxigenic Vibrio cholerae O1 in the aquatic environment of Bangladesh and its correlation with the clinical strains - Islam,M. S.; Talukder,K. A.; Khan,N. H.; Mahmud,Z. H.; Rahman,M. Z.; Nair,G. B.; Siddique,A. K. M.; Yunus,M.; Sack,D. A.; Sack,R. B.; Rita R Colwell (Microbiology and immunology, 2004)

Vehicle detection and tracking using acoustic and video sensors - Chellapa, Rama; Qian,Gang; Qinfen Zheng (Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, 2004)
Multimodal sensing has attracted much attention in solving a wide range of problems, including target detection, tracking, classification, activity understanding, speech recognition, etc. In surveillance applications, different types of sensors, such as video and acoustic sensors, provide distinct observations of ongoing activities. We present a fusion framework using both video and acoustic sensors for vehicle detection and tracking. In the detection phase, a rough estimate of target direction-of-arrival (DOA) is first obtained using acoustic data through beam-forming techniques. This initial DOA estimate designates the approximate target location in video. Given the initial target position, the DOA is refined by moving target detection using the video data. Markov chain Monte Carlo techniques are then used for joint audio-visual tracking. A novel fusion approach has been proposed for tracking, based on different characteristics of audio and visual trackers. Experimental results using both synthetic and real data are presented. Improved tracking performance has been observed by fusing the empirical posterior probability density functions obtained using both types of sensors.
Keywords: acoustic; applications; audio; audio-visual; beam-forming; Carlo; chain; density; detection; direction-of-arrival; DOA; empirical; estimation; framework; functions; fusion; fusion; joint; Markov; methods; Monte; moving; multimodal; object; optical; posterior; probability; probability; processes; processing; sensing; sensor; sensors; signal; Surveillance; surveillance; systems; target; techniques; tracking; vehicle; video

Viable but Nonculturable Vibrio Cholerae O1 in the Aquatic Environment of Argentina - Binsztein,Norma; Costagliola,Marcela C.; Pichel,Mariana; Jurquiza,Verónica; Ramírez,Fernando C.; Akselman,Rut; Vacchino,Marta; Huq,Anwarul; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2004)
In Argentina, as in other countries of Latin America, cholera has occurred in an epidemic pattern. Vibrio cholerae O1 is native to the aquatic environment, and it occurs in both culturable and viable but nonculturable (VNC) forms, the latter during interepidemic periods. This is the first report of the presence of VNC V. cholerae O1 in the estuarine and marine waters of the Río de la Plata and the Argentine shelf of the Atlantic Ocean, respectively. Employing immunofluorescence and PCR methods, we were able to detect reservoirs of V. cholerae O1 carrying the virulence-associated genes ctxA and tcpA. The VNC forms of V. cholerae O1 were identified in samples of water, phytoplankton, and zooplankton; the latter organisms were mainly the copepods Acartia tonsa, Diaptomus sp., Paracalanus crassirostris, and Paracalanus parvus. We found that under favorable conditions, the VNC form of V. cholerae can revert to the pathogenic, transmissible state. We concluded that V. cholerae O1 is a resident of Argentinean waters, as has been shown to be the case in other geographic regions of the world.

Video-Based Automatic Target Recognition - Zhou,S. K; Chellapa, Rama; Mei,Xue; Wu,Hao; Qinfen Zheng (MARYLAND UNIV COLLEGE PARK CENTER FOR AUTOMATION RESEARCH, 2004)
We present an approach for vehicle classification in IR video sequences by integrating detection, tracking and recognition. The method has two steps. First, the moving target is automatically detected using a detection algorithm. Next, we perform simultaneous tracking and recognition using an appearance-model based particle filter. The tracking result is evaluated at each frame. Low confidence in tracking performance initiates a new cycle of detection, tracking and classification. We demonstrate the robustness of the proposed method using outdoor IR video sequences.
Keywords: *SEQUENCES(MATHEMATICS); *TARGET RECOGNITION; *VEHICLES; *VIDEO RECORDING; algorithms; AUTOMATIC TRACKING.; COMPONENT REPORTS; MOVING TARGETS; SURFACE TRANSPORTATION AND EQUIPMENT; SYMPOSIA; TARGET CLASSIFICATION; TARGET DIRECTION, RANGE AND POSITION FINDING; tracking; VIDEO SIGNALS

View independent human body pose estimation from a single perspective image - Parameswaran, V.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on, 2004)
Recovering the 3D coordinates of various joints of the human body from an image is a critical first step for several model-based human tracking and optical motion capture systems. Unlike previous approaches that have used a restrictive camera model or assumed a calibrated camera, our work deals with the general case of a perspective uncalibrated camera and is thus well suited for archived video. The input to the system is an image of the human body and correspondences of several body landmarks, while the output is the set of 3D coordinates of the landmarks in a body-centric coordinate system. Using ideas from 3D model based invariants, we set up a polynomial system of equations in the unknown head pitch, yaw and roll angles. If we are able to make the often-valid assumption that the torso twist is small, there are finite numbers of solutions to the head-orientation that can be computed readily. Once the head orientation is computed, the epipolar geometry of the camera is recovered, leading to solutions to the 3D joint positions. Results are presented on synthetic and real images.
Keywords: 3D; analysis; biomechanics; body; body-centric; camera; capture; coordinate; coordinates; detection; epipolar; equation; estimation; geometry; human; image; image; images; model-based; models; MOTION; object; optical; perspective; physiological; polynomial; polynomials; pose; real; single; synthetic; system; systems; torso; tracking; twist; uncalibrated

Visual tracking and recognition using appearance-adaptive models in particle filters - Zhou,Shaohua Kevin; Chellapa, Rama; Moghaddam, B. (IEEE Transactions on Image Processing, 2004)
We present an approach that incorporates appearance-adaptive models in a particle filter to realize robust visual tracking and recognition algorithms. Tracking needs modeling interframe motion and appearance changes, whereas recognition needs modeling appearance changes between frames and gallery images. In conventional tracking algorithms, the appearance model is either fixed or rapidly changing, and the motion model is simply a random walk with fixed noise variance. Also, the number of particles is typically fixed. All these factors make the visual tracker unstable. To stabilize the tracker, we propose the following modifications: an observation model arising from an adaptive appearance model, an adaptive velocity motion model with adaptive noise variance, and an adaptive number of particles. The adaptive-velocity model is derived using a first-order linear predictor based on the appearance difference between the incoming observation and the previous particle configuration. Occlusion analysis is implemented using robust statistics. Experimental results on tracking visual objects in long outdoor and indoor video sequences demonstrate the effectiveness and robustness of our tracking algorithm. We then perform simultaneous tracking and recognition by embedding them in a particle filter. For recognition purposes, we model the appearance changes between frames and gallery images by constructing the intra- and extrapersonal spaces. Accurate recognition is achieved when confronted by pose and view variations.
Keywords: adaptive filters; adaptive noise variance; algorithms; appearance-adaptive model; Artificial intelligence; Cluster Analysis; Computer Graphics; Computer simulation; Feedback; Filtering; first-order linear predictor; hidden feature removal; HUMANS; Image Enhancement; Image Interpretation, Computer-Assisted; image recognition; Information Storage and Retrieval; Kinematics; Laboratories; Male; Models, Biological; Models, Statistical; MOTION; Movement; Noise robustness; Numerical Analysis, Computer-Assisted; occlusion analysis; Particle filters; Particle tracking; Pattern Recognition, Automated; Predictive models; Reproducibility of results; robust statistics; Sensitivity and Specificity; Signal Processing, Computer-Assisted; State estimation; statistical analysis; Subtraction Technique; tracking; Training data; visual recognition; visual tracking

Visualizations for taxonomic and phylogenetic trees - Parr,C.S.; Lee,B.; Campbell,D.; Bederson, Benjamin B. (Bioinformatics, 2004)

Wide baseline image registration with application to 3-D face modeling - Roy-Chowdhury, A.K.; Chellapa, Rama; Keaton, T. (Multimedia, IEEE Transactions on, 2004)
Establishing correspondence between features in two images of the same scene taken from different viewing angles is a challenging problem in image processing and computer vision. However, its solution is an important step in many applications like wide baseline stereo, three-dimensional (3-D) model alignment, creation of panoramic views, etc. In this paper, we propose a technique for registration of two images of a face obtained from different viewing angles. We show that prior information about the general characteristics of a face obtained from video sequences of different faces can be used to design a robust correspondence algorithm. The method works by matching two-dimensional (2-D) shapes of the different features of the face (e.g., eyes, nose etc.). A doubly stochastic matrix, representing the probability of match between the features, is derived using the Sinkhorn normalization procedure. The final correspondence is obtained by minimizing the probability of error of a match between the entire constellation of features in the two sets, thus taking into account the global spatial configuration of the features. The method is applied for creating holistic 3-D models of a face from partial representations. Although this paper focuses primarily on faces, the algorithm can also be used for other objects with small modifications.
Keywords: 2D; 3D; algorithm; baseline; biometrics; Computer; configuration; correspondence; doubly; error; extraction; Face; feature; holistic; image; matching; matrix; minimization; modeling; models; normalization; probability; probability; procedure; processes; processing; recognition; registration; representation; sequences; shapes; Sinkhorn; spatial; statistics; Stochastic; video; vision; wide

A 4-Year Study of the Epidemiology of Vibrio Cholerae in Four Rural Areas of Bangladesh - Sack,R. Bradley; Siddique,A. Kasem; Longini,Ira M.; Nizam,Azhar; Yunus,Md; M. Sirajul Islam; Morris,Jr; Ali,Afsar; Huq,Anwar; Nair,G. Balakrish; Qadri,Firdausi; Faruque,Shah M.; et al. (Journal of Infectious DiseasesJ Infect Dis., 2003)
How Vibrio cholerae spreads around the world and what determines its seasonal peaks in endemic areas are not known. These features of cholera have been hypothesized to be primarily the result of environmental factors associated with aquatic habitats that can now be identified. Since 1997, fortnightly surveillance in 4 widely separated geographic locations in Bangladesh has been performed to identify patients with cholera and to collect environmental data. A total of 5670 patients (53% <5 years of age) have been studied; 14.3% had cholera (10.4% due to V. cholerae O1 El Tor, 3.8% due to O139). Both serogroups were found in all locations; outbreaks were seasonal and often occurred simultaneously. Water-use patterns showed that bathing and washing clothes in tube-well water was significantly protective in two of the sites. These data will be correlated with environmental factors, to develop a model for prediction of cholera outbreaks

Accurate dense optical flow estimation using adaptive structure tensors and a parametric model - Liu,Haiying; Chellapa, Rama; Rosenfeld, A. (Image Processing, IEEE Transactions on, 2003)
An accurate optical flow estimation algorithm is proposed in this paper. By combining the three-dimensional (3D) structure tensor with a parametric flow model, the optical flow estimation problem is converted to a generalized eigenvalue problem. The optical flow can be accurately estimated from the generalized eigenvectors. The confidence measure derived from the generalized eigenvalues is used to adaptively adjust the coherent motion region to further improve the accuracy. Experiments using both synthetic sequences with ground truth and real sequences illustrate our method. Comparisons with classical and recently published methods are also given to demonstrate the accuracy of our algorithm.
Keywords: 3D; accuracy; adaptive; and; coherent; confidence; dense; eigenfunctions; eigenvalue; eigenvalues; eigenvectors; estimation; flow; generalized; ground; image; measure; model; MOTION; optical; parameter; parametric; problem; real; region; sequences; structure; synthetic; tensor; tensors; three-dimensional; truth

Activity modeling and recognition using shape theory - Chellapa, Rama; Vaswani, N.; Chowdhury, A.K.R. (Behavior Representation in Modeling and Simulation, 2003)
Understanding activities arising out of the interactions of aconfiguration of moving objects is an important problem in video understanding, with applications in surveillance and monitoring, animation, medicine, etc. In this paper, we in- troduce a novel method for activity modeling based on the observation that that every activity has with it an associated structure characterized by a non-rigid shape and a dynamic model that characterizes the variations in the structure as the activity unfolds. We propose two mathematical models to characterize the non-rigid shape and its dynamics. In our first approach, we propose to model an activity by the polygonal shape formed by joining the locations of these point masses at any time , and its deformation over time. This uses the statistical shape theory of Kendall. The second approach models the trajectories of each separate class of moving objects in 3D shape space, and thus can identify dif- ferent kinds of activities. It is based on the factorization the- orem for matrices, which has been used before in computer vision for structure estimation. Deviations from the learned normal shape for each activity is used to identify abnormal ones. We demonstrate the applicability of our algorithms using real-life video sequences in an airport surveillance environment. We are able to identify the major activities that take place in that setting and detect abnormal ones.

Activity recognition using the dynamics of the configuration of interacting objects - Vaswani, N.; RoyChowdhury, A.; Chellapa, Rama (Computer Vision and Pattern Recognition, 2003. Proceedings. 2003 IEEE Computer Society Conference on, 2003)
Monitoring activities using video data is an important surveillance problem. A special scenario is to learn the pattern of normal activities and detect abnormal events from a very low resolution video where the moving objects are small enough to be modeled as point objects in a 2D plane. Instead of tracking each point separately, we propose to model an activity by the polygonal 'shape' of the configuration of these point masses at any time t, and its deformation over time. We learn the mean shape and the dynamics of the shape change using hand-picked location data (no observation noise) and define an abnormality detection statistic for the simple case of a test sequence with negligible observation noise. For the more practical case where observation (point locations) noise is large and cannot be ignored, we use a particle filter to estimate the probability distribution of the shape given the noisy observations up to the current time. Abnormality detection in this case is formulated as a change detection problem. We propose a detection strategy that can detect both 'drastic' and 'slow' abnormalities. Our framework can be directly applied for object location data obtained using any type of sensors - visible, radar, infrared or acoustic.
Keywords: 2D; abnormal; abnormality; abnormality; acoustic; activity; analysis; change; Computer; configuration; configuration; data; DETECTION; detection; distribution; drastic; dynamics; event; filter; hand-picked; image; infrared; interacting; learning; location; low; mean; model; monitoring; MOTION; moving; noise; noisy; object; object; observation; observation; particle; pattern; plane; point; polygonal; probability; probability; problem; processing; radar; recognition; resolution; sensor; sensors; sequence; SHAPE; shape; signal; slow; statistic; strategy; Surveillance; surveillance; target; test; tracking; video; video; visible; vision

An adaptive quality of service aware middleware for replicated services - Krishnamurthy,Sudha; Sanders,W. H.; Michel Cukier (Parallel and Distributed Systems, IEEE Transactions on, 2003)
A dependable middleware should be able to adaptively share the distributed resources it manages in order to meet diverse application requirements, even when the quality of service (QoS) is degraded due to uncertain variations in load and unanticipated failures. We have addressed this issue in the context of a dependable middleware that adaptively manages replicated servers to deliver a timely and consistent response to time-sensitive client applications. These applications have specific temporal and consistency requirements, and can tolerate a certain degree of relaxed consistency in exchange for better response time. We propose a flexible QoS model that allows clients to specify their timeliness and consistency constraints. We also propose an adaptive framework that dynamically selects replicas to service a client's request based on the prediction made by probabilistic models. These models use the feedback from online performance monitoring of the replicas to provide probabilistic guarantees for meeting a client's QoS specification. The experimental results we have obtained demonstrate the role of feedback and the efficacy of simple analytical models for adaptively sharing the available replicas among the users under different workload scenarios.
Keywords: distributed resource sharing; Middleware; online performance monitoring; probabilistic modeling; QoS specification; quality of service; replica consistency; replicated services; resource allocation; time-sensitive client applications; timeliness constraints

Adaptive visual tracking and recognition using particle filters - Zhou,Shaohua; Chellapa, Rama; Moghaddam, B. (Multimedia and Expo, 2003. ICME '03. Proceedings. 2003 International Conference on, 2003)
This paper presents an improved method for simultaneous tracking and recognition of human faces from video, where a time series model is used to resolve the uncertainties in tracking and recognition. The improvements mainly arise from three aspects: (i) modeling the inter-frame appearance changes within the video sequence using an adaptive appearance model and an adaptive-velocity motion model; (ii) modeling the appearance changes between the video frames and gallery images by constructing intra- and extra-personal spaces; and (iii) utilization of the fact that the gallery images are in frontal views. By embedding them in a particle filter, we are able to achieve a stabilized tracker and an accurate recognizer when confronted by pose and illumination variations.
Keywords: adaptive; adaptive-velocity; appearance; extra-personal; Filtering; filters; image; intra-personal; model; MOTION; particle; processing; recognition; sequence; sequences; series; signal; spaces; theory; TIME; tracking; video; visual

Airborne Video Registration for Activity Monitoring - Shekhar,Chandra; Chellapa, Rama (Video RegistrationVideo Registration, 2003)
The analysis of ground activities involving vehicles and humans is of interest in airborne surveillance applications. The high spatiotemporal resolution of a video camera makes it the sensor of choice for such applications. In the past, video sensors were not preferred, precisely because of the high volume of data generated, which had to be processed manually for the most part. Further, the moving platform gives rise to numerous false alarms.

ANNUAL REVIEW & FORECAST REPORTS-THE OCEANS: TO PROTECT AND TO PLOW - Rita R Colwell (Sea Technology, 2003)

An appearance based approach for human and object tracking - Capellades,M. B; David Doermann; DeMenthon,D.; Chellapa, Rama (Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on, 2003)
A system for tracking humans and detecting human-object interactions in indoor environments is described. A combination of correlogram and histogram information is used to model object and human color distributions. Humans and objects are detected using a background subtraction algorithm. The models are built on the fly and used to track them on a frame by frame basis. The system is able to detect when people merge into groups and segment them during occlusion. Identities are preserved during the sequence, even if a person enters and leaves the scene. The system is also able to detect when a person deposits or removes an object from the scene. In the first case the models are used to track the object retroactively in time. In the second case the objects are tracked for the rest of the sequence. Experimental results using indoor video sequences are presented.
Keywords: algorithm; analysis; background; basis; by; Color; colour; correlogram; detection; distributions; frame; histogram; human; image; information; object; processing; segmentation; sequences; signal; subtraction; tracking; video

AQuA: an adaptive architecture that provides dependable distributed objects - Ren,Yansong; Bakken,D. E.; Courtney,T.; Michel Cukier; Karr,D. A.; Rubel,P.; Sabnis,C.; Sanders,W. H.; Schantz,R.E.; Seri,M. (Computers, IEEE Transactions on, 2003)
Building dependable distributed systems from commercial off-the-shelf components is of growing practical importance. For both cost and production reasons, there is interest in approaches and architectures that facilitate building such systems. The AQuA architecture is one such approach; its goal is to provide adaptive fault tolerance to CORBA applications by replicating objects. The AQuA architecture allows application programmers to request desired levels of dependability during applications' runtimes. It provides fault tolerance mechanisms to ensure that a CORBA client can always obtain reliable services, even if the CORBA server object that provides the desired services suffers from crash failures and value faults. AQuA includes a replicated dependability manager that provides dependability management by configuring the system in response to applications' requests and changes in system resources due to faults. It uses Maestro/Ensemble to provide group communication services. It contains a gateway to intercept standard CORBA IIOP messages to allow any standard CORBA application to use AQuA. It provides different types of replication schemes to forward messages reliably to the remote replicated objects. All of the replication schemes ensure strong, data consistency among replicas. This paper describes the AQuA architecture and presents, in detail, the active replication pass-first scheme. In addition, the interface to the dependability manager and the design of the dependability manager replication are also described. Finally, we describe performance measurements that were conducted for the active replication pass-first scheme, and we present results from our study of fault detection, recovery, and blocking times.
Keywords: active replication pass-first scheme; adaptive architecture; adaptive fault tolerance; AQuA; CORBA; data consistency; data integrity; dependable distributed objects; distributed object management; performance measurements; quality of service; replicated dependability manager; replication schemes; software fault tolerance; system resources

Architectural Interaction Diagrams: AIDs for System Modeling - Ray,Arnab; Cleaveland, Rance (Software Engineering, International Conference on, 2003)
This paper develops a modeling paradigm called Architectural Interaction Diagrams, or AIDs, for the high-level design of systems containing concurrent, interacting components. The novelty of AIDs is that they introduce interaction mechanisms, or buses, as first-class entities into the modeling vocabulary. Users then have the capability, in their modeling, of using buses whose behavior captures interaction at a higher level of abstraction than that afforded by modeling notations such as Message Sequence Charts or process algebra, which typically provide only one fixed interaction mechanism. This paper defines AIDs formally by giving them an operational semantics that describes how buses combine subsystem transitions into system-level transitions. This semantics enables AIDs to be simulated; to incorporate subsystems given in different modeling notations into a single system model; and to use testing, debugging and model checking early in the system design cycle in order to catch design errors before they are implemented.

Bistro: a scalable and secure data transfer service for digital government applications - Golubchik,Leana; Cheng,William C.; Chou,Cheng-Fu; Khuller, Samir; Samet, Hanan; Wan,C. Justin (Communications of the ACM, 2003)
Government at all levels is a major collector and provider of data.Our project focuses on the collection of data over wide-area networks (WANs) and addresses the scalability issues that arise in the context of Internet-based massive data collection applications. Furthermore, security, due to the need for privacy and integrity of the data, is a central issue for data collection applications that use a public infrastructure such as the Internet. Numerous digital government applications require data collection over WANs [5].One compelling example of such an application is the Internal Revenue Service's electronic submission of income tax forms. Other digital government applications include collecting census data, federal statistics, and surveys; gathering and tallying of electronic votes; collecting crime data for the U.S. Justice department; collecting data from sensors for disaster response applications; collecting data from geological surveys; collecting electronic filings of patents, permits, and securities (for SEC) applications; grant proposals and contract bids submissions; and so on. All these applications have scalability and security needs in common.The poor performance that may be experienced by current digital government users, given the existing state of technology (as in Figure 1a), is largely due to how (independent) data transfers using TCP/IP work over the Internet. TCP/IP is good at equally sharing bandwidth between data streams, which in large-scale applications can lead to poor performance for individual clients (as they receive only a very small share of this bandwidth). Given that TCP/IP is here to stay for the foreseeable future, what is needed is a scalable yet cost- effective solution that can be easily deployed over the existing Internet technology.We are designing and developing a system called Bistro, which addresses the scalability needs of digital government data collection applications while allowing them to share the same infrastructure and resources efficiently, cost-effectively, and securely [1]. Bistro's basic approach is to introduce intermediate hosts---bistros---which allow replacement of a traditionally "synchronized client push" approach with a "nonsynchronized combination of client-push and server-pull" approach (as depicted in Figure 1b). This in turn allows spreading of the workload on the destination server and the network over time, with subsequent elimination of hot spots as well as significant improvements in performance for both clients and servers. Our ongoing research [2, 4] indicates that orders of magnitude of improvement can be achieved with the Bistro architecture and the corresponding data collection algorithms it affords.Bistro's design allows for a gradual deployment and experimentation over the Internet (by simply downloading Bistro server software and installing it on public servers). Bistro's security protocol and trust structure [3] are designed such that only encrypted data travels through (not necessarily trusted) bistros. This means a government agency does not need to trust bistros installed by other agencies or commercial institutions. At the same time, these (untrusted) bistros can significantly improve the agency's data collection performance. Each application (within each agency) can have its own scalability, security, fault tolerance, and other data collection needs, and these applications and agencies can still share available resources, if so desired, across all Bistro servers.We believe an appropriately designed single infrastructure such as Bistro can address all digital government wide-area data collection needs in a scalable, secure, and cost-effective manner. (For more information, see bourbon.usc.edu/iml/bistro/.

Bistro: a scalable and secure data transfer service for digital government applications - Golubchik,Leana; Cheng,William C.; Chou,Cheng-Fu; Khuller, Samir; Samet, Hanan; Wan,C. Justin (Commun. ACM, 2003)
Government at all levels is a major collector and provider of data.Our project focuses on the collection of data over wide-area networks (WANs) and addresses the scalability issues that arise in the context of Internet-based massive data collection applications. Furthermore, security, due to the need for privacy and integrity of the data, is a central issue for data collection applications that use a public infrastructure such as the Internet. Numerous digital government applications require data collection over WANs [5].One compelling example of such an application is the Internal Revenue Service's electronic submission of income tax forms. Other digital government applications include collecting census data, federal statistics, and surveys; gathering and tallying of electronic votes; collecting crime data for the U.S. Justice department; collecting data from sensors for disaster response applications; collecting data from geological surveys; collecting electronic filings of patents, permits, and securities (for SEC) applications; grant proposals and contract bids submissions; and so on. All these applications have scalability and security needs in common.The poor performance that may be experienced by current digital government users, given the existing state of technology (as in Figure 1a), is largely due to how (independent) data transfers using TCP/IP work over the Internet. TCP/IP is good at equally sharing bandwidth between data streams, which in large-scale applications can lead to poor performance for individual clients (as they receive only a very small share of this bandwidth). Given that TCP/IP is here to stay for the foreseeable future, what is needed is a scalable yet cost- effective solution that can be easily deployed over the existing Internet technology.We are designing and developing a system called Bistro, which addresses the scalability needs of digital government data collection applications while allowing them to share the same infrastructure and resources efficiently, cost-effectively, and securely [1]. Bistro's basic approach is to introduce intermediate hosts---bistros---which allow replacement of a traditionally "synchronized client push" approach with a "nonsynchronized combination of client-push and server-pull" approach (as depicted in Figure 1b). This in turn allows spreading of the workload on the destination server and the network over time, with subsequent elimination of hot spots as well as significant improvements in performance for both clients and servers. Our ongoing research [2, 4] indicates that orders of magnitude of improvement can be achieved with the Bistro architecture and the corresponding data collection algorithms it affords.Bistro's design allows for a gradual deployment and experimentation over the Internet (by simply downloading Bistro server software and installing it on public servers). Bistro's security protocol and trust structure [3] are designed such that only encrypted data travels through (not necessarily trusted) bistros. This means a government agency does not need to trust bistros installed by other agencies or commercial institutions. At the same time, these (untrusted) bistros can significantly improve the agency's data collection performance. Each application (within each agency) can have its own scalability, security, fault tolerance, and other data collection needs, and these applications and agencies can still share available resources, if so desired, across all Bistro servers.We believe an appropriately designed single infrastructure such as Bistro can address all digital government wide-area data collection needs in a scalable, secure, and cost-effective manner. (For more information, see bourbon.usc.edu/iml/bistro/.