19th Biennial Conference on Mechanical Vibration and Noise - Gupta,A. K.; Fadel,G. M.; Lewicki,D. G.; Shabana,A. A.; Royston,T. J.; Gupta,S.K.; Hayes,C.; Herrmann,J.W.; Dym,C. L.; Schmidt,L. C. (American Society of Mechanical Engineers, 2003)

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 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

Adaptive Probabilistic Search for Peer-to-Peer Networks - Tsoumakos,Dimitrios; Roussopoulos, Nick (Peer-to-Peer Computing, IEEE International Conference on, 2003)
Peer-to-Peer networks are gaining increasing attention from both the scientific and the large Internet user community. Popular applications utilizing this new technology offer many attractive features to a growing number of users. At the heart of such networks lies the search algorithm. Proposed methods either depend on the network-disastrous flooding and its variations or utilize various indices too expensive to maintain. In this paper, we describe an adaptive, bandwidth-efficient algorithm for search in unstructured Peer-to-Peer networks, the Adaptive Probabilistic Search method (APS). Our scheme utilizes feedback from previous searches to probabilistically guide future ones. It performs efficient object discovery while inducing zero overhead over dynamic network operations. Extensive simulation results show that APS achieves high success rates, increased number of discovered objects, very low bandwidth consumption and adaptation to changing topologies.

An Analysis of Smoothing Effects of Upwinding Strategies for the Convection-Diffusion Equation - Elman, Howard; Alison Ramage (SIAM Journal on Numerical Analysis, 2003)
Using a technique for constructing analytic expressions for discrete solutions to the convection-diffusion equation, we examine and characterize the effects of upwinding strategies on solution quality. In particular, for grid-aligned flow and discretization based on bilinear finite elements with streamline upwinding, we show precisely how the amount of upwinding included in the discrete operator affects solution oscillations and accuracy when different types of boundary layers are present. This analysis provides a basis for choosing a streamline upwinding parameter which also gives accurate solutions for problems with non-grid-aligned and variable speed flows. In addition, we show that the same analytic techniques provide insight into other discretizations, such as a finite difference method that incorporates streamline diffusion and the isotropic artificial diffusion method.

Approximation Algorithms for Channel Allocation Problems in Broadcast Networks - Gandhi,Rajiv; Khuller, Samir; Srinivasan, Aravind; Wang,Nan (Approximation, Randomization, and Combinatorial Optimization: Algorithms and Techniques, 2003)
We study two packing problems that arise in the area of dissemination-based information systems; a second theme is the study of distributed approximation algorithms. The problems considered have the property that the space occupied by a collection of objects together could be significantly less than the sum of the sizes of the individual objects. In the Channel Allocation Problem , there are users who request subsets of items. There are a fixed number of channels that can carry an arbitrary amount of information. Each user must get all of the requested items from one channel, i.e., all the data items of each request must be broadcast on some channel. The load on any channel is the number of items that are broadcast on that channel; the objective is to minimize the maximum load on any channel. We present approximation algorithms for this problem and also show that the problem is MAX-SNP hard. The second problem is the Edge Partitioning Problem addressed by Goldschmidt, Hochbaum, Levin, and Olinick ( Networks, 41:13-23, 2003 ). Each channel here can deliver information to at most k users, and we aim to minimize the total load on all channels. We present an O ( n⅓ )–approximation algorithm and also show that the algorithm can be made fully distributed with the same approximation guarantee; we also generalize to the case of hypergraphs.

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.

AUDIO-P2. 1: PITCH AND TIMBRE MANIPULATIONS USING CORTICAL REPRESENTATION OF SOUND - Zotkin,Dmitry N; Shamma,S.A.; Ru,P.; Duraiswami, Ramani; Davis, Larry S. (IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS SPEECH AND SIGNAL PROCESSING, 2003)

Balancing performance and data freshness in web database servers - Labrinidis,A.; Roussopoulos, Nick (Proceedings of the 29th international conference on Very large data bases-Volume 29, 2003)

A characterisation of oscillations in the discrete two-dimensional convection-diffusion equation - Elman, Howard; Ramage, A. (Mathematics of computation, 2003)

Characterization of a Vibrio cholerae phage isolated from the coastal water of Peru - Talledo,Miguel; Rivera,Irma N. G.; Lipp,Erin K.; Neale,Angela; Karaolis,David; Huq,Anwar; Rita R Colwell (Environmental Microbiology, 2003)
A Vibrio cholerae bacteriophage, family Myoviridae, was isolated from seawater collected from the coastal water of Lima, Peru. Genome size was estimated to be 29 kbp. The temperate phage was specific to V. cholerae and infected 12/13 V. cholerae O1 strains and half of the four non-O1/non-O139 strains tested in this study. Vibrio cholerae O139 strains were resistant to infection and highest infection rates were obtained in low nutrient media amended with NaCl or prepared using seawater as diluent.

A collaborative digital library for children - Druin, Allison; Revelle,G.; Bederson, Benjamin B.; Hourcade,J. P; Farber,A.; Lee,J.; Campbell,D. (Journal of Computer Assisted Learning, 2003)

Comparing bootstrap and posterior probability values in the four-taxon case - Cummings, Michael P.; Handley,S. A; Myers,D. S; Reed,D. L; Rokas,A.; Winka,K. (Syst Biol, 2003)
Assessment of the reliability of a given phylogenetic hypothesis is an important step in phylogenetic analysis. Historically, the nonparametric bootstrap procedure has been the most frequently used method for assessing the support for specific phylogenetic relationships. The recent employment of Bayesian methods for phylogenetic inference problems has resulted in clade support being expressed in terms of posterior probabilities. We used simulated data and the four-taxon case to explore the relationship between nonparametric bootstrap values (as inferred by maximum likelihood) and posterior probabilities (as inferred by Bayesian analysis). The results suggest a complex association between the two measures. Three general regions of tree space can be identified: (1) the neutral zone, where differences between mean bootstrap and mean posterior probability values are not significant, (2) near the two-branch corner, and (3) deep in the two-branch corner. In the last two regions, significant differences occur between mean bootstrap and mean posterior probability values. Whether bootstrap or posterior probability values are higher depends on the data in support of alternative topologies. Examination of star topologies revealed that both bootstrap and posterior probability values differ significantly from theoretical expectations; in particular, there are more posterior probability values in the range 0.85-1 than expected by theory. Therefore, our results corroborate the findings of others that posterior probability values are excessively high. Our results also suggest that extrapolations from single topology branch-length studies are unlikely to provide any general conclusions regarding the relationship between bootstrap and posterior probability values.

A comparison of peer-to-peer search methods - Tsoumakos,D.; Roussopoulos, Nick (Proceedings of the Sixth International Workshop on the Web and Databases, 2003)

Cost minimization during simulated evolution of paired neural networks leads to asymmetries and specialization - Shkuro,Y.; Reggia, James A. (Cognitive Systems Research, 2003)

On the Covering Steiner Problem - Gupta,Anupam; Srinivasan, Aravind (FST TCS 2003: Foundations of Software Technology and Theoretical Computer ScienceFST TCS 2003: Foundations of Software Technology and Theoretical Computer Science, 2003)
The Covering Steiner problem is a common generalization of the k -MST and Group Steiner problems. An instance of the Covering Steiner problem consists of an undirected graph with edge-costs, and some subsets of vertices called groups , with each group being equipped with a non-negative integer value (called its requirement ); the problem is to find a minimum-cost tree which spans at least the required number of vertices from every group. When all requirements are equal to 1, this is the Group Steiner problem. While many covering problems (e.g., the covering integer programs such as set cover) become easier to approximate as the requirements increase, the Covering Steiner problem remains at least as hard to approximate as the Group Steiner problem; in fact, the best guarantees previously known for the Covering Steiner problem were worse than those for Group Steiner as the requirements became large. In this work, we present an improved approximation algorithm whose guarantee equals the best known guarantee for the Group Steiner problem.

Designing a digital library for young children: An intergenerational partnership - Druin, Allison; Bederson, Benjamin B.; Hourcade,J. P; Sherman,L.; Revelle,G.; Platner,M.; Weng,S. (The craft of information visualization: readings and reflections, 2003)

Desparately seeking cebuano - Oard, Douglas; David Doermann; Dorr, Bonnie J; He,D.; Resnik, Philip; Weinberg, Amy; Byrne,W.; Khudanpur,S.; Yarowsky,D.; Leuski,A.; others (Third Conference on Human Language Technologies, 2003)
This paper describes an effort to rapidly de-velop language resources and component tech- nology to support searching Cebuano news sto- ries using English queries. Results from the first 60 hours of the exercise are presented.

Direct Detection of Vibrio Cholerae and ctxA in Peruvian Coastal Water and Plankton by PCR - Lipp,Erin K.; Rivera,Irma N. G.; Gil,Ana I.; Espeland,Eric M.; Choopun,Nipa; Louis,Valérie R.; Russek-Cohen,Estelle; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2003)
Seawater and plankton samples were collected over a period of 17 months from November 1998 to March 2000 along the coast of Peru. Total DNA was extracted from water and from plankton grouped by size into two fractions (64 μm to 202 μm and >202 μm). All samples were assayed for Vibrio cholerae, V. cholerae O1, V. cholerae O139, and ctxA by PCR. Of 50 samples collected and tested, 33 (66.0%) were positive for V. cholerae in at least one of the three fractions. Of these, 62.5% (n = 32) contained V. cholerae O1; ctxA was detected in 25% (n = 20) of the V. cholerae O1-positive samples. None were positive for V. cholerae O139. Thus, PCR was successfully employed in detecting toxigenic V. cholerae directly in seawater and plankton samples and provides evidence for an environmental reservoir for this pathogen in Peruvian coastal waters.

The dog genome: survey sequencing and comparative analysis - Kirkness,E. F; Bafna,V.; Halpern,A. L; Levy,S.; Remington,K.; Rusch,D. B; Delcher,A. L; Pop, Mihai; Wang,W.; Fraser,C. M; others (Science, 2003)

The Dog Genome: Survey Sequencing and Comparative Analysis - Kirkness,Ewen F.; Bafna,Vineet; Halpern,Aaron L.; Levy,Samuel; Remington,Karin; Rusch,Douglas B; Delcher,Arthur L.; Pop, Mihai; Wang,Wei; Fraser,Claire M.; Venter,J. Craig (ScienceScience, 2003)
A survey of the dog genome sequence (6.22 million sequence reads; 1.5× coverage) demonstrates the power of sample sequencing for comparative analysis of mammalian genomes and the generation of species-specific resources. More than 650 million base pairs (>25%) of dog sequence align uniquely to the human genome, including fragments of putative orthologs for 18,473 of 24,567 annotated human genes. Mutation rates, conserved synteny, repeat content, and phylogeny can be compared among human, mouse, and dog. A variety of polymorphic elements are identified that will be valuable for mapping the genetic basis of diseases and traits in the dog.

Efficient dissemination of aggregate data over the wireless web - Sharaf,M. A; Sismanis,Y.; Labrinidis,A.; Chrysanthis,P.; Roussopoulos, Nick (International Workshop on the Web and Databases (WebDB), 2003)

Eight lessons learned during COTS-based systems maintenance - Reifer,D.J.; Basili, Victor R.; Boehm,B.W.; Clark,B. (Software, IEEE, 2003)
To make better decisions relative to CBSs, we need empirical knowledge. To gain this knowledge, we must more fully understand the lifecycle processes people use when harnessing COTS packages. The initial findings reported here are but the first step in our attempts to capture this empirical knowledge. We plan to continue collecting data and investigating the phenomenology of COTS-based systems.
Keywords: COTS; COTS-based; cycle; life; lifecycle; Maintenance; maintenance; object-oriented; packages; phase; processes; programming; reusability; software; systems

Errors - Ralston,Anthony; Shneiderman, Ben (Encyclopedia of Computer ScienceEncyclopedia of Computer Science, 2003)
The indignant customer who receives an incorrect bill from a department store probably does not care what the source of the error was or even that, almost certainly, the fault was not a computer's but rather that of its data entry personnel or programmers. Neither is the astronaut who is descending toward the surface of the Moon very concerned about the precise source of the error that caused the onboard computer to fail. But an understanding of the sources of errors in computers is important to anyone who wishes to use or comprehend digital computers.

Evaluating Translational Correspondence using Annotation Projection - Hwa,R.; Resnik, Philip; Weinberg, Amy; Kolak,O. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2003)
Recently, statistical machine translation models have begun to take advantage of higherlevel linguistic structures such as syntactic dependencies. Underlying these models is an assumption about the directness of translational correspondence between sentences in the two languages; however, the extent to which this assumption is valid and useful is not well understood. In this paper, we present an empirical study that quantifies the degree to which syntactic dependencies are preserved when parses are projected directly from En- glish to Chinese. Our results show that although the direct correspondence assumption is often too restrictive, a small set of principled, elementary linguistic transformations can boost the quality of the projected Chinese parses by 76% relative to the unimproved baseline.

Extracting significant features from the HRTF - Raykar,V.C.; Duraiswami, Ramani; Davis, Larry S.; Yegnanarayana,B. (Proceedings of the 2003 International Conference on Auditory Display, 2003)
The Head Related Transfer Function (HRTF) characterizes the au-ditory cues created by scattering of sound off a person’s anatomy. While it is known that features in the HRTF can be associated with various phenomena, such as head diffraction, head and torso re- flection, knee reflection and pinna resonances and anti resonances, identification of these phenomena are usually qualitative and/or heuristic. The objective of this paper is to attempt to decompose the HRTF and extract significant features that are perceptually im- portant for source localization. Some of the significant features that have been identified are the pinna resonances and the notches in the spectrum caused by various parts of the body. We develop signal processing algorithms to decompose the HRTF into compo- nents, and extract the features corresponding to each component. The support of NSF award ITR-0086075 is gratefully acknowl- edged

Extracting significant features from the hrtf - Raykar,V.C.; Duraiswami, Ramani; Davis, Larry S.; Yegnanarayana,B. (Proceedings of the 2003 International Conference on Auditory Display, 2003)
The Head Related Transfer Function (HRTF) characterizes the au-ditory cues created by scattering of sound off a person’s anatomy. While it is known that features in the HRTF can be associated with various phenomena, such as head diffraction, head and torso re- flection, knee reflection and pinna resonances and anti resonances, identification of these phenomena are usually qualitative and/or heuristic. The objective of this paper is to attempt to decompose the HRTF and extract significant features that are perceptually im- portant for source localization. Some of the significant features that have been identified are the pinna resonances and the notches in the spectrum caused by various parts of the body. We develop signal processing algorithms to decompose the HRTF into compo- nents, and extract the features corresponding to each component. The support of NSF award ITR-0086075 is gratefully acknowl- edged

Face recognition: A literature survey - Zhao, W.; Chellapa, Rama; Phillips,P.J.; Rosenfeld, A. (ACM Comput. Surv., 2003)
As one of the most successful applications of image analysis and understanding, face recognition has recently received significant attention, especially during the past several years. At least two reasons account for this trend: the first is the wide range of commercial and law enforcement applications, and the second is the availability of feasible technologies after 30 years of research. Even though current machine recognition systems have reached a certain level of maturity, their success is limited by the conditions imposed by many real applications. For example, recognition of face images acquired in an outdoor environment with changes in illumination and/or pose remains a largely unsolved problem. In other words, current systems are still far away from the capability of the human perception system.This paper provides an up-to-date critical survey of still- and video-based face recognition research. There are two underlying motivations for us to write this survey paper: the first is to provide an up-to-date review of the existing literature, and the second is to offer some insights into the studies of machine recognition of faces. To provide a comprehensive survey, we not only categorize existing recognition techniques but also present detailed descriptions of representative methods within each category. In addition, relevant topics such as psychophysical studies, system evaluation, and issues of illumination and pose variation are covered.
Keywords: face recognition; person identification

Face reconstruction from monocular video using uncertainty analysis and a generic model - Roy Chowdhury,Amit K.; Chellapa, Rama (Computer Vision and Image Understanding, 2003)
Reconstructing a 3D model of a human face from a monocular video sequence is an important problem in computer vision, with applications to recognition, surveillance, multimedia, etc. However, the quality of 3D reconstructions using structure from motion (SfM) algorithms is often not satisfactory. One of the reasons is the poor quality of the input video data. Hence, it is important that 3D face reconstruction algorithms take into account the statistics representing the quality of the video. Also, because of the structural similarities of most faces, it is natural that the performance of these algorithms can be improved by using a generic model of a face. Most of the existing work using this approach initializes the reconstruction algorithm with this generic model. The problem with this approach is that the algorithm can converge to a solution very close to this initial value, resulting in a reconstruction which resembles the generic model rather than the particular face in the video which needs to be modeled. In this paper, we propose a method of 3D reconstruction of a human face from video in which the 3D reconstruction algorithm and the generic model are handled separately. We show that it is possible to obtain a reasonably good 3D SfM estimate purely from the video sequence, provided the quality of the input video is statistically assessed and incorporated into the algorithm. The final 3D model is obtained after combining the SfM estimate and the generic model using an energy function that corrects for the errors in the estimate by comparing the local regions in the two models. The main advantage of our algorithm over others is that it is able to retain the specific features of the face in the video sequence even when these features are different from those of the generic model and it does so even as the quality of the input video varies. The evolution of the 3D model through the various stages of the algorithm and an analysis of its accuracy are presented.
Keywords: Energy function minimization; Face modeling; Generic model; stochastic approximation; structure from motion; uncertainty analysis

Fast two-frame multiscale dense optical flow estimation using discrete wavelet filters - Liu,Haiying; Chellapa, Rama; Rosenfeld,Azriel (Journal of the Optical Society of America AJ. Opt. Soc. Am. A, 2003)
A multiscale algorithm with complexity O(N) (where N is the number of pixels in one image) using wavelet filters is proposed to estimate dense optical flow from two frames. Hierarchical image representation by wavelet decomposition is integrated with differential techniques in a new multiscale framework. It is shown that if a compactly supported wavelet basis with one vanishing moment is carefully selected, hierarchical image, first-order derivative, and corner representations can be obtained from the wavelet decomposition. On the basis of this result, three of the four components of the wavelet decomposition are employed to estimate dense optical flow with use of only two frames. This overcomes the “flattening-out” problem in traditional pyramid methods, which produce large errors when low-texture regions become flat at coarse levels as a result of blurring. A two-dimensional affine motion model is used to formulate the optical flow problem as a linear system, with all resolutions simultaneously (i.e., coarse-and-fine) rather than the traditional coarse-to-fine approach, which unavoidably propagates errors from the coarse level. This not only helps to improve the accuracy but also makes the hardware implementation of our algorithm simple. Experiments on different types of image sequences, together with quantitative and qualitative comparisons with several other optical flow methods, are given to demonstrate the effectiveness and the robustness of our algorithm.
Keywords: digital image processing; Image analysis; optical flow

Formal verification of an intrusion-tolerant group membership protocol - Ramasamy,H. V.; Michel Cukier; Sanders,W. H. (IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS E SERIES D, 2003)
The traditional approach for establishing thecorrectness of group communication protocols is through rigor- ous arguments. While this is a valid approach, the likelihood of subtle errors in the design and implementation of such complex distributed protocols is not negligible. The use of formal verifi- cation methods has been widely advocated to instill confidence in the correctness of protocols. In this paper, we describe how we used the SPIN model checker to formally verify a group mem- bership protocol that is part of an intrusion-tolerant group com- munication system. We describe how we successfully tackled the state-space explosion problem by determining the right abstrac- tion level for formally specifying the protocol. The verification exercise not only formally showed that the protocol satisfies its correctness claims, but also provided information that will help us make the protocol more efficient without violating correctness. key words: intrusion tolerance, group communication systems, validation, formal methods

Gait Analysis for Human Identification - Kale, A.; Cuntoor, N.; Yegnanarayana,B.; Rajagopalan, AN; Chellapa, Rama (Audio- and Video-Based Biometric Person AuthenticationAudio- and Video-Based Biometric Person Authentication, 2003)
Human gait is an attractive modality for recognizing people at a distance. In this paper we adopt an appearance-based approach to the problem of gait recognition. The width of the outer contour of the binarized silhouette of a walking person is chosen as the basic image feature. Different gait features are extracted from the width vector such as the dowsampled, smoothed width vectors, the velocity profile etc. and sequences of such temporally ordered feature vectors are used for representing a person’s gait. We use the dynamic time-warping (DTW) approach for matching so that non-linear time normalization may be used to deal with the naturally-occuring changes in walking speed. The performance of the proposed method is tested using different gait databases.

A generative probabilistic OCR model for NLP applications - Kolak,O.; Byrne,W.; Resnik, Philip (Proceedings of the 2003 Conference of the North American Chapter of the Association for Computational Linguistics on Human Language Technology-Volume 1, 2003)

The genome sequence of Bacillus anthracis Ames and comparison to closely related bacteria - Read,Timothy D.; Peterson,Scott N.; Tourasse,Nicolas; Baillie,Les W.; Paulsen,Ian T.; Nelson,Karen E.; Tettelin,Herv|[eacute]|; Fouts,Derrick E.; Eisen,Jonathan A.; Gill,Steven R.; Holtzapple,Erik K.; |[Oslash]|kstad,Ole Andreas; et al. (Nature, 2003)
Bacillus anthracis is an endospore-forming bacterium that causes inhalational anthrax1. Key virulence genes are found on plasmids (extra-chromosomal, circular, double-stranded DNA molecules) pXO1 (ref. 2) and pXO2 (ref. 3). To identify additional genes that might contribute to virulence, we analysed the complete sequence of the chromosome of B. anthracis Ames (about 5.23 megabases). We found several chromosomally encoded proteins that may contribute to pathogenicity—including haemolysins, phospholipases and iron acquisition functions—and identified numerous surface proteins that might be important targets for vaccines and drugs. Almost all these putative chromosomal virulence and surface proteins have homologues in Bacillus cereus, highlighting the similarity of B. anthracis to near-neighbours that are not associated with anthrax4. By performing a comparative genome hybridization of 19 B. cereus and Bacillus thuringiensis strains against a B. anthracis DNA microarray, we confirmed the general similarity of chromosomal genes among this group of close relatives. However, we found that the gene sequences of pXO1 and pXO2 were more variable between strains, suggesting plasmid mobility in the group. The complete sequence of B. anthracis is a step towards a better understanding of anthrax pathogenesis.

Guidelines for interdomain traffic engineering - Feamster, Nick; Borkenhagen,Jay; Rexford,Jennifer (SIGCOMM Comput. Commun. Rev., 2003)
Network operators must have control over the flow of traffic into, out of, and across their networks. However, the Border Gateway Protocol (BGP) does not facilitate common traffic engineering tasks, such as balancing load across multiple links to a neighboring AS or directing traffic to a different neighbor. Solving these problems is difficult because the number of possible changes to routing policies is too large to exhaustively test all possibilities, some changes in routing policy can have an unpredictable effect on the flow of traffic, and the BGP decision process implemented by router vendors limits an operator's control over path selection.We propose fundamental objectives for interdomain traffic engineering and specific guidelines for achieving these objectives within the context of BGP. Using routing and traffic data from the AT&T backbone we show how certain BGP policy changes can move traffic in a predictable fashion, despite limited knowledge about the routing policies in neighboring AS's. Then, we show how operators can gain greater flexibility by relaxing some steps in the BGP decision process and ensuring that neighboring AS's send consistent advertisements at each peering location. Finally, we show that an operator can manipulate traffic efficiently by changing the routes for a small number of prefixes (or groups of related prefixes) that consistently receive a large amount of traffic.

Help! I’m lost: User frustration in web navigation - Lazar,J.; Bessiere,K.; Ceaparu,I.; Robinson,J.; Shneiderman, Ben (IT & Society, 2003)
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 can lead to increased frustration. Implications for designers and users are discussed.

A hidden Markov model based framework for recognition of humans from gait sequences - Sundaresan,Aravind; RoyChowdhury,Amit; Chellapa, Rama (Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on, 2003)
In this paper we propose a generic framework based on hidden Markov models (HMMs) for recognition of individuals from their gait. The HMM framework is suitable, because the gait of an individual can be visualized as his adopting postures from a set, in a sequence which has an underlying structured probabilistic nature. The postures that the individual adopts can be regarded as the states of the HMM and are typical to that individual and provide a means of discrimination. The framework assumes that, during gait, the individual transitions between N discrete postures or states but it is not dependent on the particular feature vector used to represent the gait information contained in the postures. The framework, thus, provides flexibility in the selection of the feature vector. The statistical nature of the HMM lends robustness to the model. In this paper we use the binarized background-subtracted image as the feature vector and use different distance metrics, such as those based on the L1 and L2 norms of the vector difference, and the normalized inner product of the vectors, to measure the similarity between feature vectors. The results we obtain are better than the baseline recognition rates reported before.
Keywords: analysis; background-subtracted; binarized; discrete; distance; feature; Gait; hidden; human; image; image; Markov; metrics; model; models; postures; recognition; sequences; vector

Hierarchical dwarfs for the rollup cube - Sismanis,Yannis; Deligiannakis,Antonios; Kotidis,Yannis; Roussopoulos, Nick (Proceedings of the 6th ACM international workshop on Data warehousing and OLAP - DOLAP '03, 2003)

Immediate Usability: Kiosk design principles from the CHI 2001 Photo Library - Kules,Bill; Kang,Hyunmo; Plaisant, Catherine; Rose,Anne; Shneiderman, Ben (Technical Reports from UMIACS, 2003)
This paper describes a novel set of design principles and guidelines forensuring the immediate usability of public access systems. These principles and guidelines were formulated while developing PhotoFinder Kiosk, a community photo library. Attendees of CHI 2001 successfully used the tool to browse and annotate collections of photographs spanning 20 years of CHI and related conferences, producing a richly annotated photo history of the field of human-computer interaction. We used observations and log data to evaluate the tool and refine the guidelines. They provide specific guidance for practitioners, as well as a useful framework for additional research in public access interfaces. Keywords Photo collection, community photo library, group annotation, public access system, direct annotation, direct manipulation, drag-and-drop, immediate usability, zero-trial learning, walk-up-and-use, casual use. (UMIACS-TR-2001-71) (HCIL-TR-2001-23)
Keywords: Technical Report

Improving the Arabidopsis genome annotation using maximal transcript alignment assemblies - Haas,Brian J.; Delcher,Arthur L.; Mount, Stephen M.; Wortman,Jennifer R.; Jr,Roger K. Smith; Hannick,Linda I.; Maiti,Rama; Ronning,Catherine M.; Rusch,Douglas B; Town,Christopher D.; Salzberg,Steven L.; White,Owen (Nucleic Acids ResearchNucl. Acids Res., 2003)
The spliced alignment of expressed sequence data to genomic sequence has proven a key tool in the comprehensive annotation of genes in eukaryotic genomes. A novel algorithm was developed to assemble clusters of overlapping transcript alignments (ESTs and full‐length cDNAs) into maximal alignment assemblies, thereby comprehensively incorporating all available transcript data and capturing subtle splicing variations. Complete and partial gene structures identified by this method were used to improve The Institute for Genomic Research Arabidopsis genome annotation (TIGR release v.4.0). The alignment assemblies permitted the automated modeling of several novel genes and >1000 alternative splicing variations as well as updates (including UTR annotations) to nearly half of the ∼27 000 annotated protein coding genes. The algorithm of the Program to Assemble Spliced Alignments (PASA) tool is described, as well as the results of automated updates to Arabidopsis gene annotations.

The interaction between zoning regulations and residential preferences as a driver of urban form - Zellner,M.L.; Riolo,R; Rand, William; Page,S.E.; Brown,D.G.; Fernandez,L.E. (Proceedings of the 2003 UTEP Distinguished Faculty and Student Symposium, 2003)

The International Children's Digital Library - Druin, Allison; Bederson, Benjamin B.; Weeks,A.; Farber,A.; Grosjean,J.; Guha,M.L.; Hourcade,J. P; Lee,J.; Liao,S.; Reuter,K.; others (First Monday, 2003)

The International Children's Digital Library: Description and analysis of first use - Druin, Allison; Bederson, Benjamin B.; Weeks,A.; Farber,A.; Grosjean,J.; Guha,M.L.; Hourcade,J. P; Lee,J.; Liao,S.; Reuter,K.; others (First Monday, 2003)

The International Children's Digital Library: viewing digital books online - Hourcade,J. P; Bederson, Benjamin B.; Druin, Allison; Rose,A.; Farber,A.; Takayama,Y. (Interacting with Computers, 2003)

Kernel snakes: non-parametric active contour models - Abd-Almageed, Wael; Smith,C.E.; Ramadan,S. (IEEE International Conference on Systems, Man and Cybernetics, 2003, 2003)
In this paper, a new non-parametric generalized formulation to statistical pressure snakes is presented. We discuss the shortcomings of the traditional pressure snakes. We then introduce a new generic pressure model that alleviates these shortcomings, based on the Bayesian decision theory. Non-parametric techniques are used to obtain the statistical models that drive the snake. We discuss the advantages of using the proposed non-parametric model compared to other parametric techniques. Multi-colored-target tracking is used to demonstrate the performance of the proposed approach. Experimental results show enhanced, real-time performance.
Keywords: Active contours; Artificial intelligence; Bayes methods; Bayesian decision theory; Bayesian methods; decision theory; Deformable models; Image edge detection; Image segmentation; Intelligent robots; Kernel; kernel snakes; Laboratories; multicolored target tracking; nonparametric active contour models; nonparametric generalized formulation; nonparametric model; nonparametric statistics; nonparametric techniques; real time performance; Robot vision systems; statistical pressure snakes; target tracking

Latency Profiles: Performance Monitoring for Wide Area Applications - Raschid, Louiqa; Wen,Hui-Fang; Gal,Avigdor; Zadorozhny,Vladimir (Internet Applications, IEEE Workshop on, 2003)
Recent technological advances have enabled the deployment of wide area applications against Internet accessible sources. A performance challenge to applications in such a setting is the unpredictable end-to-end latency of accessing these sources. We use passive information gathering mechanisms to learn end-to-end latency distributions and construct Latency Profiles (LPs). We hypothesize that a group of clients, within an autonomous system (AS), that are accessing a content server, in another AS, may be represented by (one or more) LPs. Related networking research on IDMaps, points of congestion, and BGP routes support such hypothesis. We develop aggregate LPs to provide coverage of groups (clusters) of client-server pairs. Using data gathered from a (limited) experiment we demonstrate the feasibility of constructing LPs.

Making miracles: Interactive translingual search for cebuano and hindi - He,D.; Oard, Douglas; Wang,J.; Luo,J.; Demner-Fushman,D.; Darwish,K.; Resnik, Philip; Khudanpur,S.; Nossal,M.; Subotin,M.; others (ACM Transactions on Asian Language Information Processing (TALIP), 2003)

Matrix Algorithms, Volume II: Eigensystems - Stewart, G.W.; Author; Mahajan,A.; Reviewer (Applied Mechanics Reviews, 2003)
Keywords: algorithm theory; Eigenvalues and eigenfunctions; linear algebra; matrix algebra; reviews

Measuring Structural Similarity of Document Pages for Searching Document Image Databases - Shin,C.; David Doermann; Rosenfeld, A. (5th IASTEDInternational Conference on Signal and Image Processing, 2003)
Current document management and database systems provide text search and retrieval capabilities, but generally lack the ability to utilize the documents’ logical and physical structures. This paper describes a general system for document image retrieval that is able to make use of document structure. It discusses the use of structural similarity for retrieval; it defines a measure of structural similarity between document images based on content area overlap, and also compares similarity ratings based on this measure with human relevance judgments.

Method of DNA extraction and application of multiplex polymerase chain reaction to detect toxigenic Vibrio cholerae O1 and O139 from aquatic ecosystems - Rivera,Irma N. G.; Lipp,Erin K.; Gil,Ana; Choopun,Nipa; Huq,Anwar; Rita R Colwell (Environmental Microbiology, 2003)
Vibrio cholerae is a free-living bacterium found in water and in association with plankton. V. cholerae non-O1/non-O139 strains are frequently isolated from aquatic ecosystems worldwide. Less frequently isolated are V. cholerae O1 and V. cholerae O139, the aetiological agents of cholera. These strains have two main virulence-associated factors, cholera toxin (CT) and toxin co-regulated pilus (TCP). By extracting total DNA from aquatic samples, the presence of pathogenic strains can be determined quickly and used to improve a microbiological risk assessment for cholera in coastal areas. Some methods suggested for DNA extraction from water samples are not applicable to all water types. We describe here a method for DNA extraction from coastal water and a multiplex polymerase chain reaction (PCR) for O1 and O139 serogroups. DNA extraction was successfully accomplished from 117 sea water samples collected from coastal areas of Perú, Brazil and the USA. DNA concentration in all samples varied from 20 ng to 480 µg µl−1. The sensitivity of the DNA extraction method was 100 V. cholerae cells in 250 ml of water. The specificity of multiplex O1/O139 PCR was investigated by analysing 120 strains of V. cholerae, Vibrio and other Bacteria species. All V. cholerae O1 and O139 tested were positive. For cholera surveillance of aquatic environments and ballast water, total DNA extraction, followed by V. cholerae PCR, and O1/O139 serogroup and tcpA/ctxA genes by multiplex PCR offers an efficient system, permitting risk analysis for cholera in coastal areas.

The Opsis project: materialized views for data warehouses and the web - Roussopoulos, Nick; Kotidis,Y.; Labrinidis,A.; Sismanis,Y. (Advances in Informatics, 2003)

Pitch and timbre manipulations using cortical representation of sound - Zotkin,Dmitry N; Shamma,S.A.; Ru,P.; Duraiswami, Ramani; Davis, Larry S. (Multimedia and Expo, IEEE International Conference on, 2003)
The sound receiver at the ears is processed by humans using signal processing that separate the signal along intensity, pitch and timbre dimensions. Conventional Fourier-based signal processing, while endowed with fast algorithms, is unable to easily represent signal along these attributes. In this paper we use a cortical representation to represent the manipulate sound. We briefly overview algorithms for obtaining, manipulating and inverting cortical representation of sound and describe algorithms for manipulating signal pitch and timbre separately. The algorithms are first used to create sound of an instrument between a guitar and a trumpet. Applications to creating maximally separable sounds in auditory user interfaces are discussed.

Predictability of Vibrio Cholerae in Chesapeake Bay - Louis,Valérie R.; Russek-Cohen,Estelle; Choopun,Nipa; Rivera,Irma N. G.; Gangle,Brian; Jiang,Sunny C.; Rubin,Andrea; Patz,Jonathan A.; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2003)
Vibrio cholerae is autochthonous to natural waters and can pose a health risk when it is consumed via untreated water or contaminated shellfish. The correlation between the occurrence of V. cholerae in Chesapeake Bay and environmental factors was investigated over a 3-year period. Water and plankton samples were collected monthly from five shore sampling sites in northern Chesapeake Bay (January 1998 to February 2000) and from research cruise stations on a north-south transect (summers of 1999 and 2000). Enrichment was used to detect culturable V. cholerae, and 21.1% (n = 427) of the samples were positive. As determined by serology tests, the isolates, did not belong to serogroup O1 or O139 associated with cholera epidemics. A direct fluorescent-antibody assay was used to detect V. cholerae O1, and 23.8% (n = 412) of the samples were positive. V. cholerae was more frequently detected during the warmer months and in northern Chesapeake Bay, where the salinity is lower. Statistical models successfully predicted the presence of V. cholerae as a function of water temperature and salinity. Temperatures above 19°C and salinities between 2 and 14 ppt yielded at least a fourfold increase in the number of detectable V. cholerae. The results suggest that salinity variation in Chesapeake Bay or other parameters associated with Susquehanna River inflow contribute to the variability in the occurrence of V. cholerae and that salinity is a useful indicator. Under scenarios of global climate change, increased climate variability, accompanied by higher stream flow rates and warmer temperatures, could favor conditions that increase the occurrence of V. cholerae in Chesapeake Bay.

Probabilistic knowledge discovery and management for P2P networks - Tsoumakos,D.; Roussopoulos, Nick (P2P Journal, 2003)

A query language to support scientific discovery - Eckman,B.; Deutsch,K.; Janer,M.; Lacroix,Z.; Raschid, Louiqa (Proc. 2nd IEEE International Computer Society, 2003)

Reduction of Cholera in Bangladeshi Villages by Simple Filtration - Rita R Colwell; Huq,Anwar; M. Sirajul Islam; K. M. A. Aziz; Yunus,M.; N. Huda Khan; A. Mahmud; Sack,R. Bradley; Nair,G. B.; J. Chakraborty; Sack,David A.; E. Russek-Cohen (Proceedings of the National Academy of SciencesPNAS, 2003)
Based on results of ecological studies demonstrating that Vibrio cholerae, the etiological agent of epidemic cholera, is commensal to zooplankton, notably copepods, a simple filtration procedure was developed whereby zooplankton, most phytoplankton, and particulates >20 μm were removed from water before use. Effective deployment of this filtration procedure, from September 1999 through July 2002 in 65 villages of rural Bangladesh, of which the total population for the entire study comprised ≈133,000 individuals, yielded a 48% reduction in cholera (P < 0.005) compared with the control.

Robust Face Recognition in the Presence of Clutter - Rajagopalan, AN; Chellapa, Rama; Koterba,Nathan (Audio- and Video-Based Biometric Person AuthenticationAudio- and Video-Based Biometric Person Authentication, 2003)
We propose a new method within the framework of principal component analysis to robustly recognize faces in the presence of clutter. The traditional eigenface recognition method performs poorly when confronted with the more general task of recognizing faces appearing against a background. It misses faces completely or throws up many false alarms. 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 and this space in conjunction with the eigenface space is used to impart robustness in the presence of background. A suitable classifier is derived to distinguish non-face patterns from faces. When tested on real images, the performance of the proposed method is found to be quite good.

SEB-tree: An approach to index continuously moving objects - Song,Z.; Roussopoulos, Nick (Mobile Data Management, 2003)

Statistical Error Propagation in 3D Modeling From Monocular Video - RoyChowdhury,Amit; Chellapa, Rama (Computer Vision and Pattern Recognition Workshop, 2003. CVPRW '03. Conference on, 2003)
A significant portion of recent research in computer vision has focused on issues related to sensitivity and robustness of existing techniques. In this paper, we study the classical structure from motion problem and analyze how the statistics representing the quality of the input video propagates through the reconstruction algorithm and affects the quality of the output reconstruction. Specifically, we show that it is possible to derive analytical expressions of the first and second order statistics (bias and error covariance) of the solution as a function of the statistics of the input. We concentrate on the case of reconstruction from a monocular video, where the small baseline makes any algorithm very susceptible to noise in the motion estimates from the video sequence. We derive an expression relating the error covariance of the reconstruction to the error covariance of the feature tracks in the input video. This is done using the implicit function theorem of real analysis and does not require strong statistical assumptions. Next, we prove that the 3D reconstruction is statistically biased, derive an expression for it and show that it is numerically significant. Combining these two results, we also establish a new bound on the minimum error in the depth reconstruction. We present the numerical significance of these analytical results on real video data.

Statistical validation of spatial patterns in agent-based models - Rand, William; Brown,D.G.; Page,S.E.; Riolo,R; Fernandez,L.E.; Zellner,M (Proceedings of Agent Based Simulation, 2003)
We present and evaluate an agent-based model(ABM) of land use change at the rural-urban fringe. This paper is part of a project that links the ABM to surveys of residential preferences and historical patterns of development. Validation is an important issue for such models and we discuss the use of distributional phenomena as a method of validation. We then highlight the ability of our ABM to gen- erate two phenomena evident in empirical analysis of urban development patterns: a power law rela- tionship between frequency and cluster size and a negative exponential relationship between density and distance from city center. We discuss these results in the light of validation of ABMs.

Techniques for interdomain traffic engineering - Feamster, Nick; Borkenhagen,J.; Rexford,J. (Computer Communications Review, 2003)
Network operators must have control over the flow of traffic into,out of, and across their networks. However, the Border Gateway Protocol (BGP) does not facilitate common traffic engineering tasks, such as balancing load across multiple links to a neighboring AS or directing traffic to a different neighbor. Solving these problems is difficult because the number of possible changes to routing policies is too large to exhaustively test all possibilities, some changes in routing policy can have an unpredictable effect on the flow of traf- fic, and the BGP decision process implemented by router vendors limits an operator’s control over path selection. We analyze routing and traffic data from the AT&T backbone to identify ways to use BGP policy for traffic engineering tasks. First, we show how cer- tain BGP policy changes can move traffic in a predictable fashion, despite limited knowledge about the routing policies in neighboring AS’s. Then, we show how operators can gain greater flexibility by relaxing some steps in the BGP decision process and ensuring that neighboring AS’s send consistent advertisements at each peering location. Finally, we show that an operator can manipulate traffic efficiently by changing the routes for a small number of prefixes (or groups of related prefixes) that consistently receive a large amount of traffic. These results can help operators accomplish common traffic engineering tasks using existing BGP features.

Technology probes: inspiring design for and with families - Hutchinson,Hilary; Mackay,Wendy; Westerlund,Bo; Bederson, Benjamin B.; Druin, Allison; Plaisant, Catherine; Beaudouin-Lafon,Michel; Conversy,Stéphane; Evans,Helen; Hansen,Heiko; Roussel,Nicolas; Eiderbäck,Björn (Proceedings of the SIGCHI conference on Human factors in computing systems, 2003)
We describe a new method for use in the process of co-designing technologies with users called technology probes. Technology probes are simple, flexible, adaptable technologies with three interdisciplinary goals: the social science goal of understanding the needs and desires of users in a real-world setting, the engineering goal of field-testing the technology, and the design goal of inspiring users and researchers to think about new technologies. We present the results of designing and deploying two technology probes, the messageProbe and the videoProbe, with diverse families in France, Sweden, and the U.S. We conclude with our plans for creating new technologies for and with families based on our experiences.
Keywords: computer mediated communication; ethnography; Home; participatory design and cooperative design

TelegraphCQ: An architectural status report - Krishnamurthy, S.; Chandrasekaran,S.; Cooper,O.; Deshpande, Amol; Franklin,M.J.; Hellerstein,J. M; Hong,W.; Madden,S.; Reiss,F.; Shah,M. A (IEEE Data Engineering Bulletin, 2003)

TelegraphCQ: continuous dataflow processing - Chandrasekaran,Sirish; Cooper,Owen; Deshpande, Amol; Franklin,Michael J.; Hellerstein,Joseph M.; Wei Hong; Krishnamurthy,Sailesh; Madden,Samuel R.; Reiss,Fred; Shah,Mehul A. (Proceedings of the 2003 ACM SIGMOD international conference on Management of data, 2003)

Tracking a moving speaker using excitation source information - Raykar,V.C.; Duraiswami, Ramani; Yegnanarayana,B.; Prasanna,S. R.M (Eighth European Conference on Speech Communication and Technology, 2003)
Microphone arrays are widely used to detect, locate, and track a stationary or moving speaker. The first step is to estimate the time delay, between the speech signals received by a pair of microphones. Conventional methods like generalized cross-correlation are based on the spectral content of the vocal tract system in the speech signal. The spectral content of the speech signal is affected due to degradations in the speech signal caused by noise and reverberation. However, features corresponding to the excitation source of speech are less affected by such degradations. This paper proposes a novel method to estimate the time delays using the excitation source information in speech. The estimated delays are used to get the position of the moving speaker. The proposed method is compared with the spectrum-based approach using real data from a microphone array setup.

Understanding Computer User Frustration: Measuring and Modeling the Disruption from Poor Designs - Bessiere,Katie; Ceaparu,Irina; Lazar,Jonathan; Robinson,John; Shneiderman, Ben (Technical Reports from UMIACS, 2003)
User frustration in the use of information and computing technology is apervasive and persistent problem. When computers crash, network congestion causes delays, and poor user interfaces trigger confusion there are dramatic consequences for individuals, organizations, and society. These frustrations not only cause personal dissatisfaction and loss of self-efficacy, but may disrupt workplaces, slow learning, and reduce participation in local and national communities. We propose a Computing Frustration Model with incident specific and individual variables to guide research. Our study of 108 computer users shows high levels of frustration and loss of 1/3 to 1/2 of time spent. The importance of the users' goals and the severity of the disruption were correlated with frustration. Those who had strong self-efficacy, indicated by a willingness to stick to solving the problem, reported lower levels of frustration. Implications for users, software developers, managers, and policymakers are discussed. Keywords: user frustration, user interface design, training, helpdesk, computer experience, computer anxiety (UMIACS-TR-2002-89) (HCIL-TR-2002-18)
Keywords: Technical Report

User-specified adaptive scheduling in a streaming media network - Hicks, Michael W.; Nagarajan,A.; van Renesse,R. (2003 IEEE Conference on Open Architectures and Network Programming, 2003)
In disaster and combat situations, mobile cameras and other sensors transmit real-time data, used by many operators or analysis tools. Unfortunately, in the face of limited, unreliable resources, and varying demands, not all users may be able to get the fidelity they require. This paper describes MediaNet, a distributed stream processing system designed with the above scenarios in mind. Unlike past approaches, MediaNet's users can intuitively specify how the system should adapt based on their individual needs. MediaNet uses both local and online global resource scheduling to improve user performance and network utilization, and adapts without requiring underlying support for resource reservations. Performance experiments show that our scheduling algorithm is reasonably fast, and that user performance and network utilization are both significantly improved.
Keywords: Adaptive scheduling; CAMERAS; Computer networks; Computer science; distributed stream processing system; Educational institutions; global resource scheduling; Intelligent networks; MediaNet; Mobile computing; network utilization; Process design; Processor scheduling; quality of service; Streaming media; streaming media network; user performance; user-specified adaptive scheduling

Using specularities for recognition - Osadchy,M.; Jacobs, David W.; Ramamoorthi,R. (Computer Vision, 2003. Proceedings. Ninth IEEE International Conference on, 2003)
Recognition systems have generally treated specular highlights as noise. We show how to use these highlights as a positive source of information that improves recognition of shiny objects. This also enables us to recognize very challenging shiny transparent objects, such as wine glasses. Specifically, we show how to find highlights that are consistent with a hypothesized pose of an object of known 3D shape. We do this using only a qualitative description of highlight formation that is consistent with most models of specular reflection, so no specific knowledge of an object's reflectance properties is needed. We first present a method that finds highlights produced by a dominant compact light source, whose position is roughly known. We then show how to estimate the lighting automatically for objects whose reflection is part specular and part Lambertian. We demonstrate this method for two classes of objects. First, we show that specular information alone can suffice to identify objects with no Lambertian reflectance, such as transparent wine glasses. Second, we use our complete system to recognize shiny objects, such as pottery.
Keywords: 3D; formation; object; glass; computer; image; information; specular; light; measurement; reflection; stereo; objects; specular; objects; wine; processing; property; pottery; recognition; recognition; object; recognition; position; reflectance; reflection; compact; reflection; transparent; shape; Lambertian; source; highlight; systems; shiny; vision; lighting; object

Using state modules for adaptive query processing - Vijayshankar Raman; Deshpande, Amol; Hellerstein,J. M (19th International Conference on Data Engineering, 2003. Proceedings, 2003)
We present a query architecture in which join operators are decomposed into their constituent data structures (State Modules, or SteMs), and dataflow among these SteMs is managed adaptively by an eddy routing operator [R. Avnur et al., (2000)]. Breaking the encapsulation of joins serves two purposes. First, it allows the eddy to observe multiple physical operations embedded in a join algorithm, allowing for better calibration and control of these operations. Second, the SteM on a relation serves as a shared materialization point, enabling multiple competing access methods to share results, which can be leveraged by multiple competing join algorithms. Our architecture extends prior work significantly, allowing continuously adaptive decisions for most major aspects of traditional query optimization: choice of access methods and join algorithms, ordering of operators, and choice of a query spanning tree. SteMs introduce significant routing flexibility to the eddy, enabling more opportunities for adaptation, but also introducing the possibility of incorrect query results. We present constraints on eddy routing through SteMs that ensure correctness while preserving a great deal of flexibility. We also demonstrate the benefits of our architecture via experiments in the Telegraph dataflow system. We show that even a simple routing policy allows significant flexibility in adaptation, including novel effects like automatic "hybridization " of multiple algorithms for a single join.
Keywords: adaptive query processing; Bandwidth; Calibration; data encapsulation; data structure; Data structures; Databases; Dictionaries; eddy routing; eddy routing operator; Encapsulation; join operator; multiple algorithm automatic hybridization; multiple competing join algorithm; query architecture; Query processing; query spanning tree; Routing; routing policy; Runtime; shared materialization point; State Module; SteMs; Telegraph dataflow system; Telegraphy; Tree data structures

Using Visualization Tools to Gain Insight Into Your Data - Plaisant, Catherine; Chintalapani,G.; Lukehart,C.; Schiro,D.; Ryan,J. (SPE Annual Technical Conference and Exhibition, 2003)
When the term ‘visualization’ is used in the oil and gas industry, it is usually referring to the viewing of complex geologic structures in three-dimensional space. This paper illustrates insights gained by applying interactive visual environments to petroleum industry data that has traditionally been presented in spreadsheets, line graphs, and bar charts. Two information visualization tools, Treemap and SpaceTree, will be shown applied to a variety of oilfield related data.

Video Mining - Rosenfeld,Azriel; David Doermann; DeMenthon,Daniel (Springer, 2003)
Video Mining is an essential reference for the practitioners and academicians in the fields of multimedia search engines.Half a terabyte or 9,000 hours of motion pictures are produced around the world every year. Furthermore, 3,000 television stations broadcasting for twenty-four hours a day produce eight million hours per year, amounting to 24,000 terabytes of data. Although some of the data is labeled at the time of production, an enormous portion remains unindexed. For practical access to such huge amounts of data, there is a great need to develop efficient tools for browsing and retrieving content of interest, so that producers and end users can quickly locate specific video sequences in this ocean of audio-visual data.Video Mining is important because it describes the main techniques being developed by the major players in industry and academic research to address this problem. It is the first time research from these leaders in the field developing the next-generation multimedia search engines is being described in great detail and gathered into a single volume.Video Mining will give valuable insights to all researchers and non-specialists who want to understand the principles applied by the multimedia search engines that are about to be deployed on the Internet, in studios' multimedia asset management systems, and in video-on-demand systems.
Keywords: Computers / Client-Server Computing; Computers / Computer Science; Computers / Database Management / Data Mining; Computers / Database Management / General; Computers / Information Technology; Computers / Information Theory; Computers / Intelligence (AI) & Semantics; Computers / Interactive & Multimedia; Computers / Networking / General; Computers / Security / Cryptography; data mining; Data mining/ Congresses; Mathematics / General; Medical / General; multimedia systems; Multimedia systems/ Congresses; Technology & Engineering / Electrical; Technology & Engineering / Telecommunications

The World's Information in Digital Libraries - Plaisant, Catherine; Marchimini,G.; Bruns,T.; Komlodi,A.; Campbell,L.; Rose,A.; Ding,G.M.; Beale Jr,J.; Nolet,V.; Shneiderman, Ben; others (The craft of information visualization: readings and reflectionsThe craft of information visualization: readings and reflections, 2003)

1.375-Approximation Algorithm for Sorting by Reversals - Berman,Piotr; Hannenhalli, Sridhar; Karpinski,Marek (Algorithms — ESA 2002Algorithms — ESA 2002, 2002)
Analysis of genomes evolving by inversions leads to a general combinatorial problem of Sorting by Reversals , MIN-SBR, the problem of sorting a permutation by a minimum number of reversals. Following a series of preliminary results, Hannenhalli and Pevzner developed the first exact polynomial time algorithm for the problem of sorting signed permutations by reversals, and a polynomial time algorithm for a special case of unsigned permutations. The best known approximation algorithm for MIN-SBR, due to Christie, gives a performance ratio of 1.5. In this paper, by exploiting the polynomial time algorithm for sorting signed permutations and by developing a new approximation algorithm for maximum cycle decomposition of breakpoint graphs, we design a new 1.375-algorithm for the MIN-SBR problem.

AAAI 2002 Workshops - Blake,Brian; Haigh,Karen; Hexmoor,Henry; Falcone,Rino; Soh,Leen-Kiat; Baral,Chitta; McIlraith,Sheila; Gmytrasiewicz,Piotr; Parsons,Simon; Malaka,Rainer; Krueger,Antonio; Bouquet,Paolo; et al. (AI Magazine, 2002)

Analysis of 16S-23S rRNA intergenic spacer of Vibrio cholerae and Vibrio mimicus for detection of these species - Chun,J.; Rivera,I. N. G.; Rita R Colwell (METHODS IN MOLECULAR BIOLOGY, 2002)

Approximation algorithms for the covering Steiner problem - Konjevod,Goran; Ravi,R.; Srinivasan, Aravind (Random Structures & Algorithms, 2002)
The covering Steiner problem is a generalization of both the k-MST and the group Steiner problems: given an edge-weighted graph, with subsets of vertices called the groups, and a nonnegative integer value (called the requirement) for each group, the problem is to find a minimum-weight tree spanning at least the required number of vertices of every group. When all requirements are equal to 1, this becomes the group Steiner problem, while if there is only one group which contains all vertices of the graph the problem reduces to k-MST with k equal to the requirement of this unique group. We discuss two different (but equivalent) linear relaxations of the problem for the case when the given graph is a tree and construct polylogarithmic approximation algorithms based on randomized LP rounding of these relaxations. By using a probabilistic approximation of general metrics by tree metrics due to Bartal, our algorithms also solve the covering Steiner problem on general graphs with a further polylogarithmic worsening in the approximation ratio. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 20:465–483, 2002

Argument structure saturation in a constraint based model - Drury,J.; Resnik, Philip; Weinberg, Amy; Gennari,S.; Aoshima,S. (2002)

Automatic transcription of Czech language oral history in the MALACH project: resources and initial experiments - Oard, Douglas; Demner-Fushman,D.; Hajic,J.; Ramabhadran,B.; Gustman,S.; Byrne,WJ; Soergel,D.; Dorr, Bonnie J; Resnik, Philip; Picheny,M. (Proceedings of the The 5th International Conference on Text, Speech and Dialogue, 2002)

Breaking the resource bottleneck for multilingual applications - Hwa,R.; Resnik, Philip; Weinberg, Amy (2002)

Combinatorial Algorithms for Design of DNA Arrays - Hannenhalli, Sridhar; Hubbell,Earl; Lipshutz,Robert; Pevzner,Pavel (Chip TechnologyChip Technology, 2002)
Optimal design of DNA arrays requires the development of algorithms with two-fold goals: reducing the effects caused by unintended illumination ( border length minimization problem ) and reducing the complexity of masks ( mask decomposition problem ). We describe algorithms that reduce the number of rectangles in mask decomposition by 20–30% as compared to a standard array design under the assumption that the arrangement of oligonucleotides on the array is fixed. This algorithm produces provably optimal solution for all studied real instances of array design. We also address the difficult problem of finding an arrangement which minimizes the border length and come up with a new idea of threading that significantly reduces the border length as compared to standard designs.

Comparative Genome Sequencing for Discovery of Novel Polymorphisms in Bacillus Anthracis - Read,Timothy D.; Salzberg,Steven L.; Pop, Mihai; Shumway,Martin; Umayam,Lowell; Jiang,Lingxia; Holtzapple,Erik; Busch,Joseph D; Smith,Kimothy L; Schupp,James M; Solomon,Daniel; Keim,Paul; et al. (Science, 2002)
Comparison of the whole-genome sequence ofBacillus anthracis isolated from a victim of a recent bioterrorist anthrax attack with a reference reveals 60 new markers that include single nucleotide polymorphisms (SNPs), inserted or deleted sequences, and tandem repeats. Genome comparison detected four high-quality SNPs between the two sequenced B. anthracischromosomes and seven differences among different preparations of the reference genome. These markers have been tested on a collection of anthrax isolates and were found to divide these samples into distinct families. These results demonstrate that genome-based analysis of microbial pathogens will provide a powerful new tool for investigation of infectious disease outbreaks.

The complex interaction of agents and environments: An example in urban sprawl - Rand, William; Zellner,M; Page,S.E.; Riolo,R; Brown,D.G.; Fernandez,L.E. (Proceedings of Agent Based Simulation, 2002)
We present and evaluate a foundational agent-based model of land use change at therural-urban fringe within the context of a larger project that will link to surveys of the environmental and community preferences of residents with historical data on patterns of development. In this paper, we focus on the dynamics arising from a model of residential location resulting from preferences for services, density, and aesthetics focusing on the relationship between micro level preferences and policy relevant macro phenomena such as scattered development, largest city size, and the number of residential clusters. We consider two representations of agents’ utility functions – one additively separable and one multiplicative – to see if functional form has any impact on the dynamics of the system, and find that they produce similar results. Our analysis includes both representative agent runs, in which all agents have identical preferences, as well as runs in which the agents have diverse preferences. We find that diversity can increase sprawl through feedbacks associated with the spatial locations of services and agents. In addition, we examine cases in which the agents’ location decisions affect the aesthetic quality of neighboring sites and find that these feedbacks further exacerbate the sprawl effect.

A configurable CORBA gateway for providing adaptable system properties - Seri,M.; Courtney,T.; Michel Cukier; Gupta,V.; Krishnmamurthy,S.; Lyons,J.; Ramasamy,H.; Ren,J.; Sanders,W. H. (2002)

DUSTer: A Method for Unraveling Cross-Language Divergences for Statistical Word-Level Alignment - Dorr, Bonnie J; Pearl,Lisa; Hwa,Rebecca; Habash,Nizar (Machine Translation: From Research to Real UsersMachine Translation: From Research to Real Users, 2002)
The frequent occurrence of divergenceS —structural differences between languages—presents a great challenge for statistical word-level alignment. In this paper, we introduce DUSTer, a method for systematically identifying common divergence types and transforming an English sentence structure to bear a closer resemblance to that of another language. Our ultimate goal is to enable more accurate alignment and projection of dependency trees in another language without requiring any training on dependency-tree data in that language. We present an empirical analysis comparing the complexities of performing word-level alignments with and without divergence handling. Our results suggest that our approach facilitates word-level alignment, particularly for sentence pairs containing divergences.

Dwarf - Sismanis,Yannis; Deligiannakis,Antonios; Roussopoulos, Nick; Kotidis,Yannis (Proceedings of the 2002 ACM SIGMOD international conference on Management of data - SIGMOD '02, 2002)

Effects of callosal lesions in a model of letter perception - Shevtsova,N.; Reggia, James A. (Cognitive, Affective, & Behavioral Neuroscience, 2002)

Empirical evaluation of techniques and methods used for achieving and assessing software high dependability - Rus,I.; Basili, Victor R.; Zelkowitz, Marvin V; Boehm,B. (Proc. DSN Workshop on Dependability Benchmarking, 2002)

Evaluating translational correspondence using annotation projection - Hwa,Rebecca; Resnik, Philip; Weinberg, Amy; Kolak,Okan (Association for Computational Linguistics, 2002)
Recently, statistical machine translation models have begun to take advantage of higher level linguistic structures such as syntactic dependencies. Underlying these models is an assumption about the directness of translational correspondence between sentences in the two languages; however, the extent to which this assumption is valid and useful is not well understood. In this paper, we present an empirical study that quantifies the degree to which syntactic dependencies are preserved when parses are projected directly from English to Chinese. Our results show that although the direct correspondence assumption is often too restrictive, a small set of principled, elementary linguistic transformations can boost the quality of the projected Chinese parses by 76% relative to the unimproved baseline.

Evaluating translational correspondence using annotation projection - Hwa,R.; Resnik, Philip; Weinberg, Amy; Kolak,O. (Proceedings of the 40th Annual Meeting on Association for Computational Linguistics, 2002)

Experimental Construction of Very Large Scale DNA Databases with Associative Search - Reif,J. H; LaBean,T. H; Pirrung,M.; Rana,V. S; Guo,B.; Kingsford, Carl; Wickham,G. S (DNA computing: 7th International Workshop on DNA-Based Computers, DNA 7, Tampa, FL, USA, June 10-13, 2001: revised papers, 2002)

Eye tracking using active deformable models - Ramadan,S.; Abd-Almageed, Wael; Smith,C.E. (Proc. of the IIIrd Indian Conference on Computer Vision, Graphics and Image Processing, 2002)

Formal specification and verification of a group membership protocol for an intrusion-tolerant group communication system - Ramasamy,H. V.; Michel Cukier; Sanders,W. H. (2002)
We describe a group membership protocol that is part of an intrusion-tolerant group communication system, and present an effort to use formal tools to model and validate our protocol. We describe in detail the most difficult part of the validation exercise, which was the determination of the right level of abstraction of the protocol for formally specifying the protocol. The validation exercise not only formally showed that the protocol satisfies its correctness claims, but also provided information that will help us make the protocol more efficient without violating correctness.
Keywords: computer network reliability; distributed processing; distributed systems; fault tolerant computing; formal specification; formal verification; group membership protocol; intrusion-tolerant group communication system; PROMELA; Protocols

Genome sequence and comparative analysis of the model rodent malaria parasite Plasmodium yoelii yoelii - Carlton,Jane M.; Angiuoli,Samuel V; Suh,Bernard B.; Kooij,Taco W.; Pertea,Mihaela; Silva,Joana C.; Ermolaeva,Maria D.; Allen,Jonathan E; Jeremy D Selengut; Koo,Hean L.; Peterson,Jeremy D.; Pop, Mihai; et al. (Nature, 2002)
Species of malaria parasite that infect rodents have long been used as models for malaria disease research. Here we report the whole-genome shotgun sequence of one species, Plasmodium yoelii yoelii, and comparative studies with the genome of the human malaria parasite Plasmodium falciparum clone 3D7. A synteny map of 2,212 P. y. yoelii contiguous DNA sequences (contigs) aligned to 14 P. falciparum chromosomes reveals marked conservation of gene synteny within the body of each chromosome. Of about 5,300 P. falciparum genes, more than 3,300 P. y. yoelii orthologues of predominantly metabolic function were identified. Over 800 copies of a variant antigen gene located in subtelomeric regions were found. This is the first genome sequence of a model eukaryotic parasite, and it provides insight into the use of such systems in the modelling of Plasmodium biology and disease.

Genomic profiles of clinical and environmental isolates of Vibrio cholerae O1 in cholera-endemic areas of Bangladesh - Zo,Y. G.; Rivera,I. N. G.; E. Russek-Cohen; Islam,M. S.; Siddique,A. K.; Yunus,M.; Sack,R. B.; Huq,A.; Rita R Colwell (Proceedings of the National Academy of Sciences, 2002)
Diversity, relatedness, and ecological interactions of toxigenic Vibrio cholerae O1 populations in two distinctive habitats, the human intestine and the aquatic environment, were analyzed. Twenty environmental isolates and 42 clinical isolates were selected for study by matching serotype, geographic location of isolation in Bangladesh, and season of isolation. Genetic profiling was done by enterobacterial repetitive intergenic consensus sequence–PCR, optimized for profiling by using the fully sequenced V. cholerae El Tor N16961 genome. Five significant clonal clusters of haplotypes were found from 57 electrophoretic types. Isolates from different areas or habitats intermingled in two of the five significant clusters. Frequencies of haplotypes differed significantly only between the environmental populations (exact test; P < 0.05). Analysis of molecular variance yielded a population genetic structure reflecting the differentiating effects of geographic area, habitat, and sampling time. Although a parameter confounding the latter differences explained 9% of the total molecular variance in the entire population (P < 0.01), the net effect of habitat and time could not be separated because of the small number of environmental isolates included in the study. Five subpopulations from a single area were determined, and from these we were able to estimate a relative differentiating effect of habitat, which was small compared with the effect of temporal change. In conclusion, the resulting population structure supports the hypothesis that spatial and temporal fluctuations in the composition of toxigenic V. cholerae populations in the aquatic environment can cause shifts in the dynamics of the disease.

Handling Translation Divergences: Combining Statistical and Symbolic Techniques in Generation-Heavy Machine Translation - Habash,Nizar; Dorr, Bonnie J (Machine Translation: From Research to Real UsersMachine Translation: From Research to Real Users, 2002)
This paper describes a novel approach to handling translation divergences in a Generation-Heavy Hybrid Machine Translation (GHMT) system. The translation divergence problem is usually reserved for Transfer and Interlingual MT because it requires a large combination of complex lexical and structural mappings. A major requirement of these approaches is the accessibility of large amounts of explicit symmetric knowledge for both source and target languages. This limitation renders Transfer and Interlingual approaches ineffective in the face of structurally-divergent language pairs with asymmetric resources. GHMT addresses the more common form of this problem, source-poor/targetrich, by fully exploiting symbolic and statistical target-language resources. This non-interlingual non-transfer approach is accomplished by using target-language lexical semantics, categorial variations and subcategorization frames to overgenerate multiple lexico-structural variations from a target-glossed syntactic dependency of the source-language sentence. The symbolic overgeneration, which accounts for different possible translation divergences, is constrained by a statistical target-language model.

Hidden loop recovery for handwriting recognition - David Doermann; Intrator,N.; Rivin,E.; Steinherz,T. (Frontiers in Handwriting Recognition, 2002. Proceedings. Eighth International Workshop on, 2002)
One significant challenge in the recognition of off-line handwriting is in the interpretation of loop structures. Although this information is readily available in online representation, close proximity of strokes often merges their centers making them difficult to identify. In this paper a novel approach to the recovery of hidden loops in off-line scanned document images is presented. The proposed algorithm seeks blobs that resemble truncated ellipses. We use a sophisticated form analysis method based on mutual distance measurements between the two sides of a symmetric shape. The experimental results are compared with the ground truth of the online representations of each off-line word image. More than 86% percent of the meaningful loops are handled correctly.
Keywords: analysis; character; contour; cursive; detection; distance; edge; ellipses; form; handwritten; hidden; loop; measurements; mutual; partitioning; recognition; recovery; SHAPE; shape; sophisticated; strokes; symmetric; truncated; word

A hierarchical approach for obtaining structure from two-frame optical flow - Liu,Haiying; Chellapa, Rama; Rosenfeld, A. (Motion and Video Computing, 2002. Proceedings. Workshop on, 2002)
A hierarchical iterative algorithm is proposed for extracting structure from two-frame optical flow. The algorithm exploits two facts: one is that in many applications, such as face and gesture recognition, the depth variation of the visible surface of an object in a scene is small compared to the distance between the optical center and the object; the other is that the time aliasing problem is alleviated at the coarse level for any two-frame optical flow estimate so that the estimate tends to be more accurate. A hierarchical representation for the relationship between the optical flow, depth, and the motion parameters is derived, and the resulting non-linear system is iteratively solved through two linear subsystems. At the coarsest level, the surface of the object tends to be flat, so that the inverse depth tends to be a constant, which is used as the initial depth map. Inverse depth and motion parameters are estimated by the two linear subsystems at each level and the results are propagated to finer levels. Error analysis and experiments using both computer-rendered images and real images demonstrate the correctness and effectiveness of our algorithm.
Keywords: algorithm; aliasing; analysis; computer-rendered; depth; depth; error; estimation; extraction; Face; feature; flow; gesture; hierarchical; image; images; inverse; iterative; methods; MOTION; nonlinear; optical; parameter; processing; real; recognition; sequences; signal; structure-from-motion; system; systems; TIME; two-frame; variation; video

Identification of humans using gait - Kale, A.; Rajagopalan, AN; Cuntoor, N.; Krueger, V.; Chellapa, Rama (IEEE Transactions on Image Processing, 2002)
We propose a view-based approach to recognize humans from their gait. Two different imagefeatures 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.

Interactive, Incremental Scheduling for Virtual Telescopes in Education - Rathod,Priyang; desJardins, Marie; Sansare,Suryakant (THIRD INTERNATIONAL NASA WORKSHOP ON PLANNING AND SCHEDULING FOR SPACE, 2002)
The Telescopes in Education (TIE) project, which began in 1992, provides remote access for students to control large observatory telescopes in real time. TIE began with a single telescope, and with manual evaluation and scheduling of student requests. With the sucess of TIE, 20 or more additional telescopes are expected to come on line. With proportionally more student requests, we anticipate that managing the requests and telescope resources will rapidly become too complex and time-consuming to handle manually. To respond to this problem, the Virtual Telescopes in Education (VTIE) project was begun last year. VTIE will provide networked capabilities for automated proposal preparation and evaluation, scheduling, and data archival. This paper describes the interactive scheduling capability that is under development for VTIE. Accepted observation requests will be incrementally and interactively scheduled by a constraint-based scheduler, and rescheduled as needed in response to dynamically changing weather and telescope conditions. The scheduling system incorporates a novel method for cost-sensitive constraint satisfaction, which will enable modeling of the costs of data gathering and user interaction during schedule repair.

Level of Detail for 3D Graphics - Luebke, David; Watson, Benjamin; Cohen, Jonathan D.; Reddy, Martin; Varshney, Amitabh (Elsevier Science Inc., 2002)
Level of detail (LOD) techniques are increasingly used by professional real-time developers to strike the balance between breathtaking virtual worlds and smooth, flowing animation. Level of Detail for 3D Graphics brings together, for the first time, the mechanisms, principles, practices, and theory needed by every graphics developer seeking to apply LOD methods.Continuing advances in level of detail management have brought this powerful technology to the forefront of 3D graphics optimization research. This book, written by the very researchers and developers who have built LOD technology, is both a state-of-the-art chronicle of LOD advances and a practical sourcebook, which will enable graphics developers from all disciplines to apply these formidable techniques to their own work.

Locating and accessing data repositories with WebSemantics - Mihaila,G. A; Raschid, Louiqa; Tomasic,A. (The VLDB journal, 2002)

Markov models of literary style for authorship identification - Rand, William (Fluctuation and Noise Letters, 2002)
The author introduces a statistical model of literary style that allows for the authorship question to be examined. This model uses Markov modeling to examine underlying patterns in pieces of literature. Different methods for comparing these models are examined. The methods are then applied to an experiment involving the authorship of 16th century sonnets. Finally suggestions for improving on this technique are discussed.

Modeling the Effects of Greenbelts at the Urban-Rural Fringe - Brown,D.G.; Page,S.E.; Riolo,R; Rand, William (Proceedings of IEMSS 2002, 2002)
We present and evaluate an agent based model (ABM) of land use change at the rural-urban fringe,comparing its performance to a mathematical model of the same process. Our simplified model was developed in Swarm using agents with heterogeneous preferences and a landscape with heterogeneous properties. The context of this work is a larger project that includes surveys of the preferences of residents and data on historical patterns of development. Our broader goal is to use the model to evaluate the ecological effects of alternative policies and designs. We begin by evaluating the influence of a greenbelt, which is located next to a developing area and in which no development is permitted. We present results of a mathematical model that illustrates the necessary trade-off between greenbelt placement and greenbelt width on its effectiveness at delaying develop- ment beyond. Experiments run with the ABM are validated by the mathematical model and illustrate analyses that can be performed by extending to two-dimensions, variable agent preferences, and multiple, and ultimately realistic, patterns of landscape variability.

Network-wide BGP route prediction for traffic engineering - Feamster, Nick; Rexford,J. (Proceedings of ITCOM, 2002)
The Internet consists of about 13,000 Autonomous Systems (AS’s) that exchange routing information using the BorderGateway Protocol (BGP). The operators of each AS must have control over the flow of traffic through their network and between neighboring AS’s. However, BGP is a complicated, policy-based protocol that does not include any direct support for traffic engineering. In previous work, we have demonstrated that network operators can adapt the flow of traffic in an efficient and predictable fashion through careful adjustments to the BGP policies running on their edge routers. Nevertheless, many details of the BGP protocol and decision process make predicting the effects of these policy changes difficult. In this paper, we describe a tool that predicts traffic flow at network exit points based on the network topology, the import policy associated with each BGP session, and the routing advertisements received from neighboring AS’s. We present a linear-time algorithm that computes a network-wide view of the best BGP routes for each destination prefix given a static snapshot of the network state, without simulating the complex details of BGP message passing. We describe how to construct this snapshot using the BGP routing tables and router configuration files available from operational routers. We verify the accuracy of our algorithm by applying our tool to routing and configuration data from AT&T’s commercial IP network. Our route prediction techniques help support the operation of large IP backbone networks, where interdomain routing is an important aspect of traffic engineering.

OCR error correction using a noisy channel model - Kolak,O.; Resnik, Philip (Proceedings of the second international conference on Human Language Technology Research, 2002)

Optimal edge-based shape detection - Moon, H.; Chellapa, Rama; Rosenfeld, A. (Image Processing, IEEE Transactions on, 2002)
We propose an approach to accurately detecting two-dimensional (2-D) shapes. The cross section of the shape boundary is modeled as a step function. We first derive a one-dimensional (1-D) optimal step edge operator, which minimizes both the noise power and the mean squared error between the input and the filter output. This operator is found to be the derivative of the double exponential (DODE) function, originally derived by Ben-Arie and Rao (1994). We define an operator for shape detection by extending the DODE filter along the shape's boundary contour. The responses are accumulated at the centroid of the operator to estimate the likelihood of the presence of the given shape. This method of detecting a shape is in fact a natural extension of the task of edge detection at the pixel level to the problem of global contour detection. This simple filtering scheme also provides a tool for a systematic analysis of edge-based shape detection. We investigate how the error is propagated by the shape geometry. We have found that, under general assumptions, the operator is locally linear at the peak of the response. We compute the expected shape of the response and derive some of its statistical properties. This enables us to predict both its localization and detection performance and adjust its parameters according to imaging conditions and given performance specifications. Applications to the problem of vehicle detection in aerial images, human facial feature detection, and contour tracking in video are presented.
Keywords: 1D; 2D; aerial; analysis; boundary; conditions; contour; cross; detection; DODE; double; edge; edge-based; error; error; exponential; extraction; facial; feature; filter; filter; Filtering; function; geometry; global; human; images; imaging; localization; mean; methods; NOISE; operator; optimal; optimisation; output; performance; pixel; power; propagation; properties; section; SHAPE; square; squared; statistical; step; theory; tracking; two-dimensional; vehicle; video

Passive replication schemes in AQuA - Ren,Yansong; Rubel,P.; Seri,M.; Michel Cukier; Sanders,W. H.; Courtney,T. (2002)
Building large-scale distributed object-oriented systems that provide multidimensional quality of service (QoS) in terms of fault tolerance, scalability, and performance is challenging. In order to meet this challenge, we need an architecture that can ensure that applications' requirements can be met while providing reusable technologies and software solutions. This paper describes techniques, based on the AQuA architecture, that enhance the applications' dependability and scalability by introducing two types of group members and a novel passive replication scheme. In addition, we describe how to make the management structure itself dependable by using the passive replication scheme. Finally, we provide performance measurements for the passive replication scheme.
Keywords: AQuA architecture; distributed object management; Fault tolerance; group members; large-scale distributed object-oriented systems; management structure; multidimensional quality of service; passive replication scheme; performance measurements; reusable technologies; scalability; software fault tolerance; software performance evaluation; software reusability; software solutions

Performance analysis of a simple vehicle detection algorithm - Moon, H.; Chellapa, Rama; Rosenfeld, A. (Image and Vision Computing, 2002)
We have performed an end-to-end analysis of a simple model-based vehicle detection algorithm for aerial parking lot images. We constructed a vehicle detection operator by combining four elongated edge operators designed to collect edge responses from the sides of a vehicle. We derived the detection and localization performance of this algorithm, and verified them by experiments. Performance degradation due to different camera angles and illuminations was also examined using simulated images. Another important aspect of performance characterization — whether and how much prior information about the scene improves performance — was also investigated. As a statistical diagnostic tool for the detection performance, a computational approach employing bootstrap was used.
Keywords: Aerial image; Bootstrap; empirical evaluation; Performance analysis; Vehicle detection

A photo history of SIGCHI: evolution of design from personal to public - Shneiderman, Ben; Kang,Hyunmo; Kules,Bill; Plaisant, Catherine; Rose,Anne; Rucheir,Richesh (interactions, 2002)
For 20 years I have been photographing personalities and events in the emerging discipline of human--computer interaction. Until now, only a few of these photos were published in newsletters or were shown to visitors who sought them out. Now this photo history is going from a personal record to a public archive. This archive should be interesting for professional members of this community who want to reminisce, as well as for historians and journalists who want to understand what happened. Students and Web surfers may also want to look at the people who created better interfaces and more satisfying user experiences.

Predicting nearest agent distances in artificial worlds - Schulz,R.; Reggia, James A. (Artificial life, 2002)

Quantifying the cost of providing intrusion tolerance in group communication systems - Ramasamy,H. V.; Pandey,P.; Lyons,J.; Michel Cukier; Sanders,W. H. (2002)
Group communication systems that provide consistent group membership and reliable, ordered multicast properties in the presence of faults resulting from malicious intrusions have not been analyzed extensively to quantify the cost of tolerating these intrusions. This paper attempts to quantify this cost by presenting results from an experimental evaluation of three new intrusion-tolerant microprotocols that have been added to an existing crash-fault-tolerant group communication system. The results are analyzed to identify the parts that contribute the most overhead during provision of intrusion tolerance at the group communication system level.
Keywords: consistent group membership; crash-fault-tolerant group communication system; cryptography; finite state machines; groupware; intrusion-tolerant microprotocols; malicious intrusions; multicast communication; reliable ordered multicast properties; security of data; Transport protocols

Sheet metal bending: forming part families for generating shared press-brake setups - Gupta,S.K.; Rajagopal,D. (Journal of manufacturing systems, 2002)
Sheet metal bending press-brakes can be setup to produce more than one type of part withoutrequiring a setup change. To exploit this flexibility, we need setup planning techniques so that press-brake setups can be shared among many different parts. In this paper, we describe algorithms for partitioning a given set of parts into setup compatible part families that can be produced on the same setup. First, we present a greedy algorithm to form part family using a bottom-up approach that makes use of the mixed integer linear programming formulation for generating shared setups for each part family. Second, we present a mixed integer linear programming formulation to generate a shared setup for a given set of parts if such a setup exists. We expect that by producing many different types of parts on the same setup, we can significantly reduce the number of setup operations, improve machine tool utilization and enable cost-effective small-batch manufacturing.

Supporting access to large digital oral history archives - Gustman,Samuel; Soergel,Dagobert; Oard, Douglas; Byrne,William; Picheny,Michael; Ramabhadran,Bhuvana; Greenberg,Douglas (Proceedings of the 2nd ACM/IEEE-CS joint conference on Digital libraries, 2002)
This paper describes our experience with the creation, indexing, and provision of access to a very large archive of videotaped oral histories - 116,000 hours of digitized interviews in 32 languages from 52,000 survivors, liberators, rescuers, and witnesses of the Nazi Holocaust. It goes on to identify a set of critical research issues that must be addressed if we are to provide full and detailed access to collections of this size: issues in user requirement studies, automatic speech recognition, automatic classification, segmentation, summarization, retrieval, and user interfaces. The paper ends by inviting others to discuss use of these materials in their own research.
Keywords: cataloging; oral history; research agenda

Temporal Color Correlograms in Video Retrieval - Rautiainen,M.; David Doermann (International Conference on Pattern Recognition, 2002)

Three-dimensional visualization of hierarchical task network plans - Kundu,K.; Sessions,C.; desJardins, Marie; Rheingans,P. (In Proceedings of the 3rd International NASA Workshop on Planning and Scheduling for, 2002)
Artificial Intelligence (AI) planning techniques, particularly hierarchical task network (HTN) planners, can produce very complex plans, with many sequential and parallel actions decomposed into multiple levels of abstraction.

Towards a criterion for evaluating the quality of 3D reconstructions - Roy Chowdhury,Amit K.; Chellapa, Rama (Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on, 2002)
Even though numerous algorithms exist for estimating the 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 information than necessary with the hope that the redundancy will help improve the quality. This raises the question about how the accuracy of the solution is related to the amount of information processed by the algorithm. Can we define the accuracy of the solution precisely enough that 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? This paper proposes an information theoretic criterion for evaluating the quality of a 3D reconstruction in terms of the statistics of the observed parameters (i.e. the image correspondences). The accuracy of the reconstruction is judged by considering the change in mutual information (or equivalently the conditional differential entropy) between a scene and its reconstructions and its effectiveness is shown through simulations.

Two-frame multi-scale optical flow estimation using wavelet decomposition - Liu,Haiying; Rosenfeld,Azriel; Chellapa, Rama (Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on, 2002)
A multi-scale algorithm using wavelet decomposition is proposed to estimate dense optical flow using only two frames. Hierarchical image representation by wavelet decomposition is used to exploit the assumption of local rigid motion in a new multi-scale framework. It is shown that if a wavelet basis with one vanishing moment is carefully selected, we can get hierarchical images, edges, and comers from the wavelet decomposition. Based on this result, all the components of the wavelet decomposition are used to estimate relatively accurate optical flow even under the inadequate image sampling condition, and overcome the #x201C;flattening-out #x201D; problem in traditional pyramid methods, which produce high errors when low-texture regions become flat at coarse levels due to blurring. Local affine transforms are also used to speed up flow estimation. Experiments on different types of image sequences together with quantitative and qualitative comparisons with several other optical flow methods are given to demonstrate the effectiveness and robustness of our algorithm.

An unsupervised method for word sense tagging using parallel corpora - Diab,M.; Resnik, Philip (Proceedings of the 40th Annual Meeting on Association for Computational Linguistics, 2002)

Using Hilbert curve in image storing and retrieving - Song,Zhexuan; Roussopoulos, Nick (Information Systems, 2002)
In this paper, we propose a method to accelerate the speed of subset query on uncompressed images. First, we change the method to store images: the pixels of images are stored on the disk in the Hilbert order instead of row-wise order that is used in traditional methods. After studying the properties of the Hilbert curve, we give a new algorithm which greatly reduces the number of data segments in subset query range. Although, we have to retrieve more data than necessary, because the speed of sequential readings is much faster than the speed of random access readings, it takes about 10% less elapsed time in our algorithm than in the traditional algorithms to execute the subset queries. In some systems, the saving is as much as 90%.
Keywords: Hilbert order; Row-wise order; Subset query

Using latency-recency profiles for data delivery on the web - Bright,L.; Raschid, Louiqa (Proceedings of the 28th international conference on Very Large Data Bases, 2002)

Video analysis applications for pervasive environments - Karunanidhi,A.; David Doermann; Parekh,N.; Rautio,V. (1st International Conference on Mobile and Ubiquitous Multimedia, 2002)
Network capabilities are expanding at arate that will soon allow a much wider range of image and video content to be delivered to and transmitted from mobile wireless devices. Current pervasive applications provide image and video content primarily in high performance networks or by streaming video over low-bandwidth networks. For video to be truly integrated into ubiquitous applications, we must carefully consider the role of automated video analysis to move beyond simple content delivery. Compression and content adaptation have been significant areas of research for some time and deal with the problem of moving media to devices with limited network, software and hardware capabilities. In the near future, mobile wireless devices that have been primarily consumers of image and video will be able to produce such content as well. In this paper, we will review some of the significant issues associated with providing video capabilities in pervasive environments. We consider not only streaming video applications, but point-to- point video and video messaging capabilities as well. We will show how our previous work on content adaptation is being applied to these types of environments, show what role more general video analysis can play and describe a general architecture for video capture, storage, analysis and transmission.

View-Based Recognition of Military Vehicles in Ladar Imagery Using CAD Model Matching - Der, S.Z.; Zheng,Q.; Redman, B.; Chellapa, Rama; Mahmoud, H. (OPTICAL ENGINEERING-NEW YORK-MARCEL DEKKER INCORPORATED-, 2002)

Virtual audio system customization using visual matching of ear parameters - Zotkin,Dmitry N; Duraiswami, Ramani; Davis, Larry S.; Mohan,A.; Raykar,V. (16th International Conference on Pattern Recognition, 2002. Proceedings, 2002)
Applications in the creation of virtual auditory spaces (VAS) and sonification require individualized head related transfer functions (HRTFs) for perceptual fidelity. HRTFs exhibit significant variation from person to person due to differences between their pinnae, and their body sizes. We propose and preliminarily implement a simple HRTF customization based on the use of a published database of HRTFs (Algazi et al., 2001) that also contains geometrical measurements of subject pinnae. We measure some of these features via simple image processing, and select the HRTF that has features most closely corresponding to the individual's features. This selection procedure is implemented along with the virtual auditory system described in (Zotkin et al., 2002), and listener tests conducted comparing the customized HRTF and a fixed HRTF. Despite the simplicity of the method, tests reveal average improvement in localization accuracy of about 25 percent, though performance improvement varies with source location and individuals.
Keywords: acoustic signal processing; Audio systems; Auditory system; Computer vision; database; Ear; ear parameter matching; geometrical measurements; Head; head related transfer functions; HRTF customization; Image databases; IMAGE PROCESSING; medical image processing; performance improvement; Position measurement; sonification; Spatial databases; System testing; Transfer functions; virtual audio system customization; virtual auditory spaces; virtual auditory system; visual matching

Virtual Telescopes in Education - Hoban,S.; desJardins, Marie; Farrell,N.; Rathod,P.; Sachs,J.; Sansare,S.; Yesha,Y.; Keating,J.; Busschots,B.; Means,J.; others (Journal of Digital Information, 2002)
Virtual Telescopes in Education is providing the services required to operate a virtual observatory comprising distributed telescopes, including an interactive, constraint-based scheduling service, data and resource archive, proposal preparation and review environment, and a VTIE Journal. A major goal of VTIE is to elicit from learners questions about the nature of celestial objects and the physical processes that give rise to the spectacular imagery that catches their imaginations. Generation of constrained science questions will assist learners in the science process. To achieve interoperability with other NSDL resources, our approach follows the Open Archives Initiative and the W3C Semantic Web activity.

A visual search tool for early elementary science students - Revelle,G.; Druin, Allison; Platner,M.; Bederson, Benjamin B.; Hourcade,J. P; Sherman,L. (Journal of Science Education and Technology, 2002)

What we have learned about fighting defects - Shull, F.; Basili, Victor R.; Boehm,B.; Brown,A. W; Costa,P.; Lindvall,M.; Port,D.; Rus,I.; Tesoriero,R.; Zelkowitz, Marvin V (Software Metrics, 2002. Proceedings. Eighth IEEE Symposium on, 2002)
The Center for Empirically Based Software Engineering helps improve software development by providing guidelines for selecting development techniques, recommending areas for further research, and supporting software engineering education. A central activity toward achieving this goal has been the running of "e- Workshops" that capture expert knowledge with a minimum of overhead effort to formulate heuristics on a particular topic. The resulting heuristics are a useful summary of the current state of knowledge in an area based on expert opinion. This paper discusses the results to date of a series of e-Workshops on software defect reduction. The original discussion items are presented along with an encapsulated summary of the expert discussion. The reformulated heuristics can be useful both to researchers (for pointing out gaps in the current state of the knowledge requiring further investigation) and to practitioners (for benchmarking or setting expectations about development practices).
Keywords: based; Center; Computer; defect; development; education; electronic; Empiric; engineering; engineering; eWorkshops; for; heuristics; reduction; Science; software; workshops

Word-level Alignment for Multilingual Resource Acquisition - Lopez,Adam; Nossal,Michael; Hwa,Rebecca; Resnik, Philip (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2002)
We present a simple, one-pass word alignment algorithm for parallel text. Our algorithm utilizes synchronous parsing and takes advantage of existing syntactic annotations. In our experiments the performance of this model is comparable to more complicated iterative methods. We discuss the challenges and potential benefits of using the model to train syntactic parsers for new languages.
Keywords: *LEARNING MACHINES; *MULTILINGUAL RESOURCES; *WORDS(LANGUAGE); ACQUISITION; algorithms; ALIGNMENT; BENEFITS; ITERATIONS; LANGUAGE; linguistics

An adaptive algorithm for tolerating value faults and crash failures - Ren,Yansong; Michel Cukier; Sanders,W. H. (Parallel and Distributed Systems, IEEE Transactions on, 2001)
The AQuA architecture provides adaptive fault tolerance to CORBA applications by replicating objects and providing a high-level method that an application can use to specify its desired level of dependability. This paper presents the algorithms that AQUA uses, when an application's dependability requirements can change at runtime, to tolerate both value faults in applications and crash failures simultaneously. In particular, we provide an active replication communication scheme that maintains data consistency among replicas, detects crash failures, collates the messages generated by replicated objects, and delivers the result of each vote. We also present an adaptive majority voting algorithm that enables the correct ongoing vote while both the number of replicas and the majority size dynamically change. Together, these two algorithms form the basis of the mechanism for tolerating and recovering from value faults and crash failures in AQuA
Keywords: active replication communication; adaptive algorithm; adaptive fault tolerance; adaptive majority voting algorithm; AQuA architecture; client-server systems; CORBA; crash failures; data consistency; data integrity; Dependability; distributed object management; fault tolerant computing; objects replication; value faults

Analysis and prediction of protein functional sub-types from protein sequence alignments - Hannenhalli, Sridhar; Russell,Robert B. (2001)
Here we present a method for analysis and prediction of functional sub-types from multiple protein sequence alignments. Given an alignment and set of proteins grouped into sub-types according to some definition of function, such as enzymatic specificity, the method identifies positions that are indicative of functional differences by subtraction of sequence profiles, and analysis of positional entropy in the alignment.

Automated Validation of Software Models - Sims,Steve; Cleaveland, Rance; Butts,Ken; Ranville,Scott (Automated Software Engineering, International Conference on, 2001)
This paper describes the application of an automated verification tool to a software model developed at Ford. Ford already has in place an advanced model-based software development framework that employs the Matlab?, Simulink?, and Stateflow? modeling tools. During this project we applied the invariant checker Salsa to a Simulink?/ Stateflow? model of automotive software to check for nondeterminism, missing cases, dead code, and redundant code. During the analysis, a number of anomalies were detected that had not been found during manual review. We argue that the detection and correction of these problems demonstrates a cost-effective application of formal verification that elevates our level of confidence in the model.

Building an Experience Base for Software Engineering: A report on the first CeBASE eWorkshop - Basili, Victor R.; Tesoriero,R.; Costa,P.; Lindvall,M.; Rus,I.; Shull, F.; Zelkowitz, Marvin V (Product Focused Software Process Improvement, 2001)
New information is obtained by research and disseminated by papers in conferences and journals. The synthesis of knowledge depends upon social discourse among the experts in a given domain to discuss the impact of this new information. Meetings among such experts are, however, expensive and time consuming. In this paper we discuss the organization of CeBASE, a center whose goal is the collection and dissemination of empirically-based software engineering knowledge, and the concept of the online workshop or eWorkshop as a way to use the Internet to minimize the needs of face-to-face meetings. We discuss the design of our eWorkshop and give the results of one eWorkshop that discussed the impact of defect reduction strategies.We want to thank Barry Boehm, Scott Henninger, Rayford Vaughn, Winsor Brown, Dan Port and Michael Frey as well as all participants for their contribution to the success of the eWorkshop. We also want to thank students at USC and UMD for their contribution in testing the system and Jennifer Dix for proof reading this paper.

A case for dynamic view management - Kotidis,Yannis; Roussopoulos, Nick (ACM Transactions on Database SystemsACM Trans. Database Syst., 2001)

Conditions enabling the emergence of inter-agent signalling in an artificial world - Reggia, James A.; Schulz,R.; Wilkinson,G. S; Uriagereka,J. (Artificial Life, 2001)

Cortical Spreading depression and the pathogenesis of brain disorders: a computational and neural network-based investigation - Ruppin,E.; Reggia, James A. (Neurological research, 2001)

Efficient algorithms for location and sizing problems in network design - Kumaran,K.; Srinivasan, Aravind; Qiong Wang; Lanning,S.; Ramakrishnan,K. G (IEEE Global Telecommunications Conference, 2001. GLOBECOM '01, 2001)
Large-scale location, sizing and homing problems of distributed network elements, have received much attention recently due to the massive deployment of broadband communication networks for services like Internet telephony and Web caching. Key considerations in designing these networks include modularity of capacity, economies of scale in cost, and reliability. We formulate a general class of such network design problems as Mixed-Integer Programs. These problems are computationally intractable in general; under various asymptotic conditions, we show how to compute near-optimal solutions. To deal with arbitrary instances, we develop new algorithms based on linear programming, as well as greedy randomized adaptive search. These algorithms achieved near-optimal solutions with reasonable computation time for our experiments
Keywords: Algorithm design and analysis; Broadband communication; broadband communication networks; broadband networks; capacity modularity; Communication networks; computer network reliability; distributed network elements; Economies of scale; greedy randomized adaptive search; homing; integer programming; Intelligent networks; Internet telephony; large-scale location problems; Large-scale systems; Linear programming; mixed-integer programs; near-optimal solutions; network design; Optical switches; randomised algorithms; reliability; search problems; sizing; Technological innovation; telecommunication network planning; Web caching

Efficient network and I/O throttling for fine-grain cycle stealing - Ryu, Kyung D.; Hollingsworth, Jeffrey K; Keleher, Peter J. (Proceedings of the 2001 ACM/IEEE conference on Supercomputing (CDROM) - Supercomputing '01, 2001)

An empirical study of regression test selection techniques - Graves,Todd L.; Harrold,Mary Jean; Kim,Jung-Min; Porter, Adam; Rothermel,Gregg (ACM Transactions on Software Engineering and MethodologyACM Trans. Softw. Eng. Methodol., 2001)

Evolving columnar circuitry for lateral cortical inhibition - Ayers,D.; Reggia, James A. (Neural Networks, 2001. Proceedings. IJCNN'01. International Joint Conference on, 2001)

Fragment completion in humans and machines - Jacobs, David W.; Rokers,B.; Rudra,A.; Liu,Z. (NIPS, 2001)

Hashing moving objects - Song,Z.; Roussopoulos, Nick (Mobile Data Management, 2001)

Improved cross-language retrieval using backoff translation - Resnik, Philip; Oard, Douglas; Levow,G. (Proceedings of the first international conference on Human language technology research, 2001)

Independence is good: dependency-based histogram synopses for high-dimensional data - Deshpande, Amol; Garofalakis,Minos; Rastogi,Rajeev (SIGMOD Rec., 2001)
Approximating the joint data distribution of a multi-dimensional data set through a compact and accurate histogram synopsis is a fundamental problem arising in numerous practical scenarios, including query optimization and approximate query answering. Existing solutions either rely on simplistic independence assumptions or try to directly approximate the full joint data distribution over the complete set of attributes. Unfortunately, both approaches are doomed to fail for high-dimensional data sets with complex correlation patterns between attributes. In this paper, we propose a novel approach to histogram-based synopses that employs the solid foundation of statistical interaction models to explicitly identify and exploit the statistical characteristics of the data. Abstractly, our key idea is to break the synopsis into (1) a statistical interaction model that accurately captures significant correlation and independence patterns in data, and (2) a collection of histograms on low-dimensional marginals that, based on the model, can provide accurate approximations of the overall joint data distribution. Extensive experimental results with several real-life data sets verify the effectiveness of our approach. An important aspect of our general, model-based methodology is that it can be used to enhance the performance of other synopsis techniques that are based on data-space partitioning (e.g., wavelets) by providing an effective tool to deal with the “dimensionality curse”.

Integrating distributed scientific data sources with MOCHA and XRoaster - Rodriguez-Martinez,M.; Roussopoulos, Nick; McGann,J. M; Kelley,S.; Mokwa,J.; White,B.; Jala,J. (Thirteenth International Conference on Scientific and Statistical Database Management, 2001. SSDBM 2001. Proceedings, 2001)
MOCHA is a novel middleware system for integrating distributed data sources that we have developed at the University of Maryland. MOCHA is based on the idea that the code that implements user-defined types and functions should be automatically deployed to remote sites by the middleware system itself. To this end, we have developed an XML-based framework to specify metadata about data sites, data sets, and user-defined types and functions. XRoaster is a graphical tool that we have developed to help the user create all the XML metadata elements to be used in MOCHA
Keywords: client-server systems; data sets; data sites; Databases; Distributed computing; distributed databases; distributed scientific data source integration; Educational institutions; graphical tool; hypermedia markup languages; IP networks; java; Large-scale systems; Maintenance engineering; meta data; metadata; Middleware; middleware system; MOCHA; Query processing; remote sites; scientific information systems; user-defined types; visual programming; XML; XML metadata elements; XML-based framework; XRoaster

Intrusion tolerance approaches in ITUA - Michel Cukier; Lyons,J.; Pandey,P.; Ramasamy,H. V.; Sanders,W. H.; Pal,P.; Webber,F.; Schantz,R.; Loyall,J.; Watro,R. (2001)

K-nearest neighbor search for moving query point - Song,Z.; Roussopoulos, Nick (Advances in Spatial and Temporal Databases, 2001)

Learning word pronunciations using a recurrent neural network - Radio,M. J; Reggia, James A.; Berndt,R. S (Neural Networks, 2001. Proceedings. IJCNN'01. International Joint Conference on, 2001)

Mapping lexical entries in a verbs database to WordNet senses - Green,Rebecca; Pearl,Lisa; Dorr, Bonnie J; Resnik, Philip (Proceedings of the 39th Annual Meeting on Association for Computational Linguistics, 2001)
This paper describes automatic techniques for mapping 9611 entries in a database of English verbs to WordNet senses. The verbs were initially grouped into 491 classes based on syntactic features. Mapping these verbs into WordNet senses provides a resource that supports disambiguation in multilingual applications such as machine translation and cross-language information retrieval. Our techniques make use of (1) a training set of 1791 disambiguated entries, representing 1442 verb entries from 167 classes; (2) word sense probabilities, from frequency counts in a tagged corpus; (3) semantic similarity of WordNet senses for verbs within the same class; (4) probabilistic correlations between WordNet data and attributes of the verb classes. The best results achieved 72% precision and 58% recall, versus a lower bound of 62% precision and 38% recall for assigning the most frequently occurring WordNet sense, and an upper bound of 87% precision and 75% recall for human judgment.

Optimized seamless integration of biomolecular data - Eckman,B. A; Lacroix,Z.; Raschid, Louiqa (Proceedings of the IEEE 2nd International Symposium on Bioinformatics and Bioengineering Conference, 2001, 2001)
Today, scientific data is inevitably digitized, stored in a variety of heterogeneous formats, and is accessible over the Internet. Scientists need to access an integrated view of multiple remote or local heterogeneous data sources. They then integrate the results of complex queries and apply further analysis and visualization to support the task of scientific discovery. Building a digital library for scientific discovery requires accessing and manipulating data extracted from flat files or databases, documents retrieved from the Web, as well as data that is locally materialized in warehouses or is generated by software. We consider several tasks to provide optimized and seamless integration of biomolecular data. Challenges to be addressed include capturing and representing source capabilities; developing a methodology to acquire and represent metadata about source contents and access costs; and decision support to select sources and capabilities using cost based and semantic knowledge, and generating low cost query evaluation plans
Keywords: analysis; Bioinformatics; biology computing; cost based knowledge; Costs; Data analysis; data mining; data visualisation; Data visualization; Data warehouses; decision support; digital library; Educational institutions; information resources; Internet; low cost query evaluation plans; Mediation; meta data; metadata; molecular biophysics; multiple local heterogeneous data sources; multiple remote heterogeneous data sources; optimized seamless biomolecular data integration; scientific discovery; scientific information systems; semantic knowledge; software libraries; visual databases; Visualization

Personal secure booting - Itoi,N.; Arbaugh, William A.; Pollack,S.; Reeves,D. (Information Security and Privacy, 2001)

Probabilistic temporal databases - Alex,D.; Robert,R.; V.S. Subrahmanian (ACM Transaction on Database Systems, 2001)

Probabilistic temporal databases, I: algebra - Dekhtyar,Alex; Ross,Robert; V.S. Subrahmanian (ACM Trans. Database Syst., 2001)
Dyreson and Snodgrass have drawn attention to the fact that, in many temporal database applications, there is often uncertainty about the start time of events, the end time of events, and the duration of events. When the granularity of time is small (e.g., milliseconds), a statement such as “Packet p was shipped sometime during the first 5 days of January, 1998” leads to a massive amount of uncertainty (5×24×60×60×1000) possibilities. As noted in Zaniolo et al. [1997], past attempts to deal with uncertainty in databases have been restricted to relatively small amounts of uncertainty in attributes. Dyreson and Snodgrass have taken an important first step towards solving this problem.In this article, we first introduce the syntax of Temporal-Probabilistic (TP) relations and then show how they can be converted to an explicit, significantly more space-consuming form, called Annotated Relations. We then present a theoretical annotated temporal algebra (TATA). Being explicit, TATA is convenient for specifying how the algebraic operations should behave, but is impractical to use because annotated relations are overwhelmingly large. Next, we present a temporal probabilistic algebra (TPA). We show that our definition of the TP-algebra provides a correct implementation of TATA despite the fact that it operates on implicit, succinct TP-relations instead of overwhemingly large annotated relations. Finally, we report on timings for an implementation of the TP-Algebra built on top of ODBC.

Probabilistic Temporal Databases, II: Calculus and Query Processing - Dekhtyar,A.; Ozcan,F.; Ross,R.; V.S. Subrahmanian (Technical Reports from UMIACS, UMIACS-TR-2001-79, 2001)
There is a vast class of applications in which we know that a certain event occurred, but do not know exactly when it occurred. However, as studied by Dyreson and Snodgrass \cite{ds98}, there are many natural scenarios where probability distributions exist and quantify this uncertainty. Dekhtyar et. al. extended Dyreson and Snodgrass's work and defined an extension of the relational algebra to handle such data. The first contribution of this paper is a declarative temporal probabilistic (TP for short) calculus which we show is equivalent in expressive power to the temporal probabilistic algebra of Dekhtyar et. al. Our second major contribution is a set of equivalence and containment results for the TP-algebra. Our third contribution is the development of cost models that may be used to estimate the cost of TP-algebra operations. Our fourth contribution is an experimental evaluation of the accuracy of our cost models and the use of the equivalence results as rewrite rules for optimizing queries by using an implementation of TP-databases on top of ODBC.

Rapidly retargetable interactive translingual retrieval - Levow,Gina-Anne; Oard, Douglas; Resnik, Philip (Proceedings of the first international conference on Human language technology research, 2001)
This paper describes a system for rapidly retargetable interactive translingual retrieval. Basic functionality can be achieved for a new document language in a single day, and further improvements require only a relatively modest additional investment. We applied the techniques first to search Chinese collections using English queries, and have successfully added French, German, and Italian document collections. We achieve this capability through separation of language-dependent and language-independent components and through the application of asymmetric techniques that leverage an extensive English retrieval infrastructure.
Keywords: cross-language; information; retrieval

Rescuing a destabilized protein fold through backbone cyclization - Camarero,Julio A; Fushman, David; Sato,Satoshi; Giriat,Izabela; Cowburn,David; Raleigh,Daniel P; Muir,Tom W (Journal of Molecular Biology, 2001)
We describe the physicochemical characterization of various circular and linear forms of the ∼60 residue N-terminal Src homology 3 (SH3) domain from the murine c-Crk adapter protein. Structural, dynamic, thermodynamic, kinetic and biochemical studies reveal that backbone circularization does not prevent the adoption of the natural folded structure in any of the circular proteins. Both the folding and unfolding rate of the protein increased slightly upon circularization. Circularization did not lead to a significant thermodynamic stabilization of the full-length protein, suggesting that destabilizing enthalpic effects (e.g. strain) negate the expected favorable entropic contribution to overall stability. In contrast, we find circularization results in a dramatic stabilization of a truncated version of the SH3 domain lacking a key glutamate residue. The ability to rescue the destabilized mutant indicates that circularization may be a useful tool in protein engineering programs geared towards generating minimized proteins.
Keywords: circular protein; ligation; SH3 domain

The role of independent verification and validation in maintaining a safety critical evolutionary software in a complex environment: the NASA Space Shuttle program - Zelkowitz, Marvin V; Rus,L. (Software Maintenance, 2001. Proceedings. IEEE International Conference on, 2001)
The National Aeronautics and Space Administration (NASA) Space Shuttle program is a multi-billion dollar activity scheduled to span over 40 years. Maintaining such software with requirements for high reliability and mission safety taxes current development methods. The authors present how independent verification and validation (IV amp;V) activities are used to support these requirements. They also show how the IV amp;V activities for this program differ from those of more traditional software developments
Keywords: activities; NASA; Administration; complex; Aeronautics; amp; V; and; computing; program; critical; developments; aerospace; environment; development; evolutionary; IV; maintenance; software; maintenance; traditional; methods; high; program; National; prototyping; space; reliability; independent; safety; safety; Shuttle; software; software; software; space; validation; mission; vehicles; verification; verification; safety-critical

Shared index scans for data warehouses - Kotidis1⋆,Y.; Sismanis,Y.; Roussopoulos, Nick (Data Warehousing and Knowledge Discovery, 2001)

Source Selection and Ranking in the WebSemantics Architecture Using Quality of Data Metadata-1 Introduction - Mihaila,G. A; Raschid, Louiqa; Vidal,M. E (Advances in Computers, 2001)

Spanish Language Processing at University of Maryland: Building Infrastructure for Multilingual Applications - Cabezas,C.; Dorr, Bonnie J; Resnik, Philip (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2001)
We describe here our construction of lexical resources, tool creation, building of an alignedparallel corpus, and an approach to automatic treebank creation that we have been de- veloping using Spanish data, based on projection of English syntactic dependency infor- mation across a parallel corpus.

Statistical Analysis in Music Information Retrieval - Rand, William; Birmingham,William P. (Proceedings of the Second Annual International Symposium on Music Information Retrieval ISMIR 2001, 2001)
We introduce a statistical model of music that allows for the retrieval of music based upon an audio input. This model uses frequency counts of state transitions to index pieces of music. Several methods of comparing these index values to choose an appropriate match are examined. We describe how this model can serve as the basis for a query-by-humming system. The model is also shown to be robust to several kinds of errors.

Supervised sense tagging using support vector machines - Cabezas,C.; Resnik, Philip; Stevens,J. (Proceedings of the Second International Workshop on Evaluating Word Sense Disambiguation Systems (SENSEVAL-2), 2001)

Understanding IV & V in a safety critical and complex evolutionary environment: the NASA space shuttle program - Zelkowitz, Marvin V; Rus,Ioana (Proceedings of the 23rd International Conference on Software Engineering, 2001)
The National Aeronautics and Space Administration is an internationally recognized leader in space science and exploration. NASA recognizes the inherent risk associated with space exploration; however, NASA makes every reasonable effort to minimize that risk. To that end for the Space Shuttle program NASA instituted a software independent verification and validation (IV&V) process in 1988 to ensure that the Shuttle and its crew are not exposed to any unnecessary risks. Using data provided by both the Shuttle software developer and the IV&V contractor, in this paper we describe the overall IV&V process as used on the Space Shuttle program and provide an analysis of the use of metrics to document and control this process. Our findings reaffirm the value of IV&V and show the impact IV&V has on multiple releases of a large complex software system.
Keywords: Evolutionary software; Life and mission critical software; metrics; Process characterization; Software independent verification and validation; Software safety and reliability; Space Shuttle program

Understanding Manufacturing Systems with a Learning Historian for User-Directed Experimentation - Chipman,G.; Plaisant, Catherine; Gahagan,S.; Herrmann,J.W.; Hewitt,S.; Reaves,L. (Department of Computer Science, University of Maryland, College Park, 2001)
This paper describes a learning historian to improve user-directed experimentation withdiscrete event simulation models of manufacturing systems. In user-directed experimentation, an analyst conducts simulation runs to estimate system performance. Then the analyst modifies the simulation model to evaluate other possibilities. An important characteristic is the ad hoc nature of the experimentation, as the analyst forms and runs new trials based on the results from previous trials. Through user-directed experimentation designers compare alternatives and students learn the relationships between input parameters and performance measures. Recording and reviewing previous trials while using simulation models enhances their benefits, transforming trial-and-error into learning. The learning historian combines a graphical user interface, a discrete event simulation model, and dynamic data visualization. Usability studies indicate that the learning historian is a usable and useful tool because it allows users to concentrate more on understanding system behavior than on operating simulation software.

Update propagation strategies for improving the quality of data on the web - Labrinidis,A.; Roussopoulos, Nick; SCIENCE,MARYLAND UNIV COLLEGE PARK DEPT OF COMPUTER (PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON VERY LARGE DATA BASES, 2001)

User modeling for information access based on implicit feedback - Kim,J.; Oard, Douglas; Romanik,K. (3rd Symposium of ISKO-France, Information Filtering and Automatic Summarisation in networds, 2001)

Validating an access cost model for wide area applications - Zadorozhny,V.; Raschid, Louiqa; Zhan,T.; Bright,L. (Cooperative Information Systems, 2001)

Adaptive query processing: Technology in evolution - Hellerstein,J. M; Franklin,M.J.; Chandrasekaran,S.; Deshpande, Amol; Hildrum,K.; Madden,S.; Raman,V.; Shah,M. A (IEEE Data Engineering Bulletin, 2000)
As query engines are scaled and federated, they must cope with highly unpredictable and changeableenvironments. In the Telegraph project, we are attempting to architect and implement a continuously adaptive query engine suitable for global-area systems, massive parallelism, and sensor networks. To set the stage for our research, we present a survey of prior work on adaptive query processing, focusing on three characterizations of adaptivity: the frequency of adaptivity, the effects of adaptivity, and the extent of adaptivity. Given this survey, we sketch directions for research in the Telegraph project.

Analysis and prediction of functional sub-types from protein sequence alignments - Hannenhalli, Sridhar; Russell,Robert B. (Journal of Molecular Biology, 2000)
The increasing number and diversity of protein sequence families requires new methods to define and predict details regarding function. Here, we present a method for analysis and prediction of functional sub-types from multiple protein sequence alignments. Given an alignment and set of proteins grouped into sub-types according to some definition of function, such as enzymatic specificity, the method identifies positions that are indicative of functional differences by comparison of sub-type specific sequence profiles, and analysis of positional entropy in the alignment. Alignment positions with significantly high positional relative entropy correlate with those known to be involved in defining sub-types for nucleotidyl cyclases, protein kinases, lactate/malate dehydrogenases and trypsin-like serine proteases. We highlight new positions for these proteins that suggest additional experiments to elucidate the basis of specificity. The method is also able to predict sub-type for unclassified sequences. We assess several variations on a prediction method, and compare them to simple sequence comparisons. For assessment, we remove close homologues to the sequence for which a prediction is to be made (by a sequence identity above a threshold). This simulates situations where a protein is known to belong to a protein family, but is not a close relative of another protein of known sub-type. Considering the four families above, and a sequence identity threshold of 30 %, our best method gives an accuracy of 96 % compared to 80 % obtained for sequence similarity and 74 % for BLAST. We describe the derivation of a set of sub-type groupings derived from an automated parsing of alignments from PFAM and the SWISSPROT database, and use this to perform a large-scale assessment. The best method gives an average accuracy of 94 % compared to 68 % for sequence similarity and 79 % for BLAST. We discuss implications for experimental design, genome annotation and the prediction of protein function and protein intra-residue distances.
Keywords: prediction; protein function; protein structure; sequence alignment

Approximation algorithms with bounded performance guarantees for the clustered traveling salesman problem - Guttmann-Beck,N.; Hassin,R.; Khuller, Samir; Raghavachari,B. (Algorithmica, 2000)
Let G=(V,E) be a complete undirected graph with vertex set V , edge set E , and edge weights l(e) satisfying triangle inequality. The vertex set V is partitioned into clusters V 1 , . . ., V k . The clustered traveling salesman problem is to compute a shortest Hamiltonian cycle (tour) that visits all the vertices, and in which the vertices of each cluster are visited consecutively. Since this problem is a generalization of the traveling salesman problem, it is NP-hard. In this paper we consider several variants of this basic problem and provide polynomial time approximation algorithms for them.

Automatic deployment of application-specific metadata and code in MOCHA - Rodriguez-Martinez,M.; Roussopoulos, Nick (Advances in Database Technology—EDBT 2000, 2000)

Centers of sets of pixels - Khuller, Samir; Rosenfeld,Azriel; Wu,Angela (Discrete Applied Mathematics, 2000)
The center of a connected graph G is the set of nodes of G for which the maximum distance to any other node of G is as small as possible. If G is a simply connected set of lattice points (“pixels”) with graph structure defined by 4-neighbor adjacency, we show that the center of G is either a 2×2 square block, a diagonal staircase, or a (dotted) diagonal line with no gaps.
Keywords: Center; Chessboard distance; City block distance; Intrinsic distance; Simply connected set

A computational model of lateralization and asymmetries in cortical maps - Levitan,S.; Reggia, James A. (Neural computation, 2000)

Cortical inhibition as explained by the competitive distribution hypothesis - Reggia, James A.; Sutton III,G. G.; Lynne,C.; D'Autrechy,S. C; Armentrout,S. L (Network models for control and processing, 2000)

Efficient expected-case algorithms for planar point location - Arya,S.; Cheng,S. W; Mount, Dave; Ramesh,H. (Algorithm Theory-SWAT 2000, 2000)

Efficient remote data access in a mobile computing environment - Bright,L.; Raschid, Louiqa (ICPP, 2000)

An empirical study of regression test application frequency - Kim,Jung-Min; Porter, Adam; Rothermel,Gregg (Proceedings of the 22nd international conference on Software engineering - ICSE '00, 2000)

Evaluation of sense disambiguation given hierarchical tag sets - Melamed,I.D.; Resnik, Philip (Computers and the Humanities, 2000)

Exploiting concurrency in a DBMS implementation for production systems - Raschid, Louiqa; Sellis,T.; Lin,C. C (Proceedings of the first international symposium on Databases in parallel and distributed systems, 2000)

Exploiting fine-grained idle periods in networks of workstations - Kyung Dong Ryu; Hollingsworth, Jeffrey K (IEEE Transactions on Parallel and Distributed Systems, 2000)
Studies have shown that for a significant fraction of the time, workstations are idle. In this paper, we present a new scheduling policy called Linger-Longer that exploits the fine-grained availability of workstations to run sequential and parallel jobs. We present a two-level workload characterization study and use it to simulate a cluster of workstations running our new policy. We compare two variations of our policy to two previous policies: Immediate-Eviction and Pause-and-Migrate. Our study shows that the Linger-Longer policy can improve the throughput of foreign jobs on a cluster by 60 percent with only a 0.5 percent slowdown of local jobs. For parallel computing, we show that the Linger-Longer policy outperforms reconfiguration strategies when the processor utilization by the local process is 20 percent or less in both synthetic bulk synchronous and real data-parallel applications
Keywords: cluster of workstations; Computer networks; Concurrent computing; Contracts; Delay; fine-grained availability; Intelligent networks; Linger-Longer; networks of workstations; PARALLEL PROCESSING; Predictive models; Processor scheduling; Resumes; scheduling policy; Throughput; workload characterization; workstation clusters; Workstations

Generating dynamic content at database-backed web servers - Labrinidis,Alexandros; Roussopoulos, Nick (ACM SIGMOD RecordSIGMOD Rec., 2000)

GP+ echo+ subsumption= improved problem solving - Punch,W.F.; Rand, William (Proceedings of the Genetic and Evolutionary Computation Conference (GECCO 2000), 2000)
Real-time, adaptive control is a difficult problemthat can be addressed by EC architectures. We are interested in incorporating into an EC architecture some of the features that Holland’s Echo architecture presents. Echo has been used to model everything from cultures to financial markets. However, the typical application of Echo is a simulation to observe the dynamics of the modeled elements such as found in control problems. We show in this paper that some aspects of Echo can be incorporated into Genetic Programming to solve control problems. The paper discusses EAGP (Echo Augmented Genetic Programming), a modified GP architecture that uses aspects of Echo, and subsumption. We demonstrate the usefulness of EAGP on a robot navigation problem

Improved Algorithms via Approximations of Probability Distributions - Chari,Suresh; Rohatgi,Pankaj; Srinivasan, Aravind (Journal of Computer and System Sciences, 2000)
We present two techniques for constructing sample spaces that approximate probability distributions. The first is a simple method for constructing the small-bias probability spaces introduced by Naor and Naor. We show how to efficiently combine this construction with the method of conditional probabilities to yield improved parallel algorithms for problems such as set discrepancy, finding large cuts in graphs, and finding large acyclic subgraphs. The second is a construction of small probability spaces approximating general independent distributions which are of smaller size than the constructions of Even, Goldreich, Luby, Nisan, and Veličković.
Keywords: derandomization; discrepancy; explicit constructions; graph coloring; Parallel algorithms; small sample spaces

Learning response time for websources using query feedback and application in query optimization - Gruser,J. R; Raschid, Louiqa; Zadorozhny,V.; Zhan,T. (The VLDB Journal—The International Journal on Very Large Data Bases, 2000)

Ligand-Receptor Pairing Via Tree Comparison - Bafna,Vineet; Hannenhalli, Sridhar; Rice,Ken; Vawter,Lisa (Journal of Computational Biology, 2000)
This paper introduces a novel class of tree comparison problems strongly motivated by an important and cost intensive step in drug discovery pipeline viz., mapping cell bound receptors to the ligands they bind to and vice versa. Tree comparison studies motivated by problems such as virus-host tree comparison, gene-species tree comparison and consensus tree problem have been reported. None of these studies are applicable in our context because in all these problems, there is a well-defined mapping of the nodes the trees are built on across the set of trees being compared. A new class of tree comparison problems arises in cases where finding the correspondence among the nodes of the trees being compared is itself the problem. The problem arises while trying to find the interclass correspondence between the members of a pair of coevolving classes, e.g., cell bound receptors and their ligands. Given the evolution of the two classes, the combinatorial problem is to find a mapping among the leaves of the two trees that optimizes a given cost function. In this work we formulate various combinatorial optimization problems motivated by the aforementioned biological problem for the first time. We present hardness results, give an efficient algorithm for a restriction of the problem and demonstrate its applicability.

Logic-based query optimization for object databases - Grant,J.; Gryz,J.; Minker, Jack; Raschid, Louiqa (IEEE Transactions on Knowledge and Data Engineering, 2000)
We present a technique for transferring query optimization techniques, developed for relational databases, into object databases. We demonstrate this technique for ODMG database schemas defined in ODL and object queries expressed in OQL. The object schema is represented using a logical representation (Datalog). Semantic knowledge about the object data model, e.g., class hierarchy information, relationship between objects, etc., as well as semantic knowledge about a particular schema and application domain are expressed as integrity constraints. An OQL object query is represented as a logic query and query optimization is performed in the Datalog representation. We obtain equivalent (optimized) logic queries, and subsequently obtain equivalent (optimized) OQL queries for each equivalent logic query. We present one optimization technique for semantic query optimization (SQO) based on the residue technique of U. Charavarthy et al. (1990; 1986; 1988). We show that our technique generalizes previous research on SQO for object databases. We handle a large class of OQL queries, including queries with constructors and methods. We demonstrate how SQO can be used to eliminate queries which contain contradictions and simplify queries, e.g., by eliminating joins, or by reducing the access scope for evaluating a query to some specific subclass(es). We also demonstrate how the definition of a method or integrity constraints describing the method, can be used in optimizing a query with a method
Keywords: access scope; application domain; class hierarchy information; Constraint optimization; data integrity; Data models; Datalog; Datalog representation; deductive databases; equivalent logic query; integrity constraints; Lifting equipment; Logic; logic based query optimization; logic programming; logic queries; logic query; logical representation; object data model; object databases; object queries; object schema; object-oriented databases; ODL; ODMG database schemas; optimization technique; optimized OQL queries; OQL object query; query languages; Query optimization; query optimization techniques; Query processing; Relational databases; residue technique; semantic knowledge; semantic query optimization

Measuring verb similarity - Resnik, Philip; Diab,M. (Proceedings of the Twenty-second Annual Conference of the Cognitive Science Society: August 13-15, 2000, Institute for Research in Cognitive Science, University of Pennsylvania, Philadelphia, PA, 2000)

MOCHA: a database middleware system featuring automatic deployment of application-specific functionality - Rodrıguez-Martinez,M.; Roussopoulos, Nick; McGann,J. M; Keyley,S.; Katz,V.; Song,Z.; JaJa, Joseph F. (Proceedings of the 2000 ACM SIGMOD International Conference on Management of Data, Dallas, Texas, 2000)

MOCHA: a self-extensible database middleware system for distributed data sources - Rodríguez-Martínez,M.; Roussopoulos, Nick (ACM SIGMOD Record, 2000)

A model for magnetic aftereffect in the presence of time varying demagnetizing fields - Korman,C.E.; Adly,A.A.; Mayergoyz, Issak D; Rugkwamsook,P. (Magnetics, IEEE Transactions on, 2000)
Preisach models driven by stochastic inputs are employed to model magnetic aftereffect in the presence of demagnetizing fields. As a result of thermal relaxation, the magnetization and, consequently, the demagnetizing field vary in time. The new model generalizes earlier work and self-consistently accounts for the effect of time varying demagnetizing fields on the relaxation process. Three practical numerical techniques are proposed to compute the time variation in the magnetic field and the state of the Preisach plane
Keywords: aftereffect; aftereffect; magnetization; numerical; demagnetizing; field; demagnetisation; magnetic; model; magnetic; Preisach; relaxation; time; simulation; thermal; varying

Off-line Skilled Forgery Detection using Stroke and Substroke Features - Guo,K.; David Doermann; Rosenfeld, A. (ICPR, 2000)

Optimal design of signaling networks for Internet telephony - Srinivasan, Aravind; Ramakrishnan,K. G; Kumaran,K.; Aravamudan,M.; Naqvi,S. (IEEE INFOCOM 2000. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings, 2000)
We present an approach for efficient design of a signaling network for a network of software switches supporting Internet telephony. While one may take an integer programming approach to solve this problem, it quickly becomes intractable even for modest-sized networks. Instead, our topology design uses random graphs that we show to be nearly optimal in cost, highly connected, and computationally efficient even for large networks. We then formulate a quadratic assignment problem (QAP) to map the abstract topology into the physical network to achieve optimal load balancing for given demand forecasts, which we solve using randomized heuristics. Numerical results on several example networks illustrate the performance and computational efficiency of our method. A graphical design tool has been developed based on our algorithms
Keywords: bandwidth allocation; Computational efficiency; Computer networks; Cost function; Demand forecasting; demand forecasts; graph theory; graphical design tool; Internet telephony; Linear programming; Load forecasting; Load management; Network topology; optimal design; optimal load balancing; optimisation; performance; quadratic assignment problem; random graphs; randomised algorithms; randomized heuristics; Signal design; signaling networks; Switches; telecommunication signalling; topology design

Producing Interoperable Queries for Relational and Object-Oriented Databases - Chang,Y. H; Raschid, Louiqa (Journal of Intelligent Information Systems, 2000)

Resource-aware meta-computing - Hollingsworth, Jeffrey K; Keleher, Peter J.; Ryu, Kyung D. (Emphasizing Distributed SystemsEmphasizing Distributed Systems, 2000)
Meta-computing, is an increasingly popular and useful method of obtaining resources to solve large computational problems. However, meta-computer environments pose a number of unique challenges, many of which have yet to be addressed effectively. Among these are dynamicism in both applications and environments, and heterogeneity at several different levels. This chapter discusses current approaches to these problems, and uses them in the Active Harmony system as a running example. Harmony supports an interface that allows applications to export tuning alternatives to the higher-level system. By exposing different parameters that can be changed at runtime, applications can be automatically adapted to changes in their execution environment caused by other programs, the addition or deletion of nodes, or changes in the availability of resources like communication links. Applications expose not only options, but also expected resource utilization with each option and the effect that the option will have on the application's performance. We discuss how this flexibility can be used to tune the overall performance of a collection of applications in a system.

Reverse Engineering and UML: A Case Study of AuctionBot - Bangera,R.; Rand, William (University of Michigan, 2000)

A Review of Current Routing Protocols for Ad Hoc - Royer,E.M.; Toh,C.K.; Hicks, Michael W.; Kakkar,P.; Moore,J. T; Hicks, Michael W.; Moore,J. T; Alexander,D. S; Gunter,C. A; Nettles,S.; others (IEEE Personal Communications, 2000)

Simulation based learning environments and the use of learning histories - Rose,A.; Salter,R.; Keswani,S.; Kositsyna,N.; Plaisant, Catherine; Rubloff,G.; Shneiderman, Ben (CHI '00 extended abstracts on Human factors in computing systems, 2000)
We have developed an application framework for constructing simulation-based learning environments using dynamic simulations and visualizations to represent realistic time-dependent behavior. The development environment is described and many examples are given. In particular we will focus on the learning historian which provides users and learners with a manipulatable recording of their actions which facilitates the exchange of annotated history records among peers and mentors.
Keywords: education; engineering; History; learning; simulation

A SIMULATION ENVIRONMENT FOR EVOLVING MULTIAGENT COMMUNICATION - Reggia, James A.; Schultz,Reiner; Uriagereka,Juan; Wilkinson,Jerry (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2000)
A simulation environment has been created to support study of emergentcommunication. Multiple agents exist in a two-dimensional world where they must find food and avoid predators. While non-communicating agents may survive, the world is configured so that survival and fitness can be enhanced through the use of inter-agent communication. The goal with this version of the simulator is to determine conditions under which simple communication (signaling) emerges and persists during an evolutionary process. (Also cross-referenced as UMIACS-TR-2000-64)
Keywords: Technical Report

The temporal correlation hypothesis for self-organizing feature maps - Chen,Y.; Reggia, James A. (International Journal of Systems Science, 2000)

Using Hilbert curve in image storing and retrieving - Song,Zhexuan; Roussopoulos, Nick (Proceedings of the 2000 ACM workshops on Multimedia - MULTIMEDIA '00, 2000)

Using quality of data metadata for source selection and ranking - Mihaila,G. A; Raschid, Louiqa; Vidal,M. E (Proceedings of the Third International Workshop on the Web and Databases, WebDB, 2000)