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

DIF: An interchange format for dataflow-based design tools - Hsu,C. J; Keceli,F.; Ko,M. Y; Shahparnia,S.; Bhattacharyya, Shuvra S. (Computer Systems: Architectures, Modeling, and Simulation, 2004)

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

Efficient peer location on the Internet - Banerjee,Suman; Kommareddy,Chris; Bhattacharjee, Bobby (Computer Networks, 2004)
We consider the problem of locating nearby application peers over the Internet. We define a new peer-location scheme (called Tiers), that scales to large application peer groups. Tiers creates a hierarchy of peers, and provides an efficient and scalable solution to the peer-location problem. Tiers can be implemented entirely in the application-layer and does not require the deployment of either any additional measurement services, or well-known reference points in the network.We have evaluated the performance of Tiers through detailed experiments. Our results show that Tiers is able to locate the nearest peers quickly (≪1 s) and accurately on wide-area Internet-like topologies. We have also compared the performance of Tiers with two other schemes, Beaconing and Distributed Binning, both of which are known to have good performance. Both these techniques are reference-points based schemes and are efficient for overlays with a small number of peers (e.g. ⩽32). Our results show that Tiers significantly outperforms both these schemes. Tiers is particularly efficient for large overlay networks, has an order of magnitude lower control overhead for overlays with 512 peers and still achieves greater accuracy in locating the nearest peers.
Keywords: Group communication; hierarchy; overlays; Peer location; triangle inequality

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

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

Enhancement of mechanical engineering curriculum to introduce manufacturing techniques and principles for bio-inspired product development - Bruck,H. A.; Gershon,A. L.; Gupta,S.K. (2004)

Finite-element computation of nonlinear magnetic diffusion and its effects when coupled to electrical, mechanical, and hydraulic systems - Brauer,J.R.; Mayergoyz, Issak D (Magnetics, IEEE Transactions on, 2004)
Finite elements are used to compute eddy currents and magnetic diffusion times in steel cylinders with nonlinear B–H curves. Computations are made of diffusion times versus current in a typical axisymmetric magnetic actuator, showing good agreement with recently published approximate analytical formulas. The computed nonlinear diffusion times are then used to derive an equivalent resistor that is used in a model of an electrohydraulic system. The diffusion time causes delays in the coupled mechanical and hydraulic responses.
Keywords: actuator; actuators; analysis; axisymmetric; B-H; coupled; currents; curves; cylinders; diffusion; diffusion; eddy; electrical; electrohydraulic; electrohydraulics; electromagnetic; element; equivalent; finite; finite-element; flux; hydraulic; magnetic; mechanical; methods; nonlinear; resistor; responses; steel; system; systems; times; transducers

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

A game-theoretic framework for analyzing trust-inference protocols - Morselli,R.; Katz, Jonathan; Bhattacharjee, Bobby (Workshop on Economics of Peer-to-Peer Systems, 2004)
We propose a novel game-theoretic framework foranalyzing the robustness of trust-inference protocols in the presence of adversarial (but rational) users. To the best of our knowledge, this is the first such framework which simultaneously (1) admits a rigor- ous and precise definition, thereby enabling formal proofs of security (in various adversarial settings) for specific trust-inference protocols; (2) is flexible enough to accommodate a full range of (realistic) ad- versarial behavior and network models; and (3) is ap- propriate for decentralized networks, and in particu- lar does not posit a trusted, centralized party with complete knowledge of the system history. We also show some preliminary results regarding the design of trust-inference protocols which can be rigorously proven secure within our model. In addition to establishing a solid foundation for future work, our framework also enables a rigorous and objective comparison among existing trust inference protocols.

Hierarchical routing with soft-state replicas in TerraDir - Silaghi,B.; Gopalakrishnan,Vijay; Bhattacharjee, Bobby; Kelcher,P. (Parallel and Distributed Processing Symposium, 2004. Proceedings. 18th International, 2004)
Summary form only given. Recent work on peer-to-peer systems has demonstrated the ability to deliver low latencies and good load balance when demand for data is relatively uniform. We describe an adaptive replication protocol that delivers low latencies, good load balance even when demand is heavily skewed. The protocol can withstand arbitrary and instantaneous changes in demand distribution. Our approach also addresses classical concerns related to topological constraints of asymmetrical namespaces, such as hierarchical bottlenecks in the context of hierarchical namespaces. The protocol replicates routing state in an ad-hoc manner based on profiled information, is lightweight, scalable, and requires no replica consistency guarantees.
Keywords: ad-hoc; adaptive; allocation; asymmetrical; balancing; bottlenecks; consistency; constraints; delivering; demand; distribution; guarantees; hierarchical; latency; load; low; namespaces; peer-to-peer; protocol; protocols; replica; replicas; replication; resource; routing; soft-state; systems; TerraDir; topological

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

iCLEF 2003 at Maryland: Translation Selection and Document Selection - Dorr, Bonnie J; He,Daqing; Luo,Jun; Oard, Douglas; Schwartz,Richard; Wang,Jianqiang; Zajic, David (Comparative Evaluation of Multilingual Information Access SystemsComparative Evaluation of Multilingual Information Access Systems, 2004)
Maryland performed two sets of experiments for the 2003 Cross-Language Evaluation Forum’s interactive track, one focused on interactive selection of appropriate translations for query terms, the second focused on interactive selection of relevant documents. Translation selection was supported using possible synonyms discovered through back translation and two techniques for generating KeyWord In Context (KWIC) examples of usage. The results indicate that searchers typically achieved a similar search effectiveness using fewer query iterations when interactive translation selection was available. For document selection, a complete extract of the first 40 words of each news story was compared to a compressed extract generated using an automated parse-and-trim approach that approximates one way in which people can produce headlines. The results indicate that compressed “headlines” result in faster assessment, but with a 20% relative reduction in the F α = 0.8 search effectiveness measure.

Implementing stable semantics by linear programming - Bell,C.; Nerode,A.; Ng,R. T; V.S. Subrahmanian (Logic Programming and Non-Monotonic Reasoning, Proceedings of the Second International Workshop, 2004)

Importing abstract spatial data into the SAND database system - Samet, Hanan; Brabec,Frantisek; Sankaranarayanan,Jagan (Proceedings of the 2004 annual national conference on Digital government research, 2004)
The World Wide Web has opened ways to operate large applications by users with simple client platforms located half way around the world by connecting servers around the world together. We present a system that makes a centrally stored spatial database available to off-site users. Regardless of the specific platform available to a user, all they need to do is simply establish a link between their client and the server. Unlike well-known web-based services such as MapQuest [2] that rely on computational power of the server, our system distributes the workload among the client and the server in such a manner that the user will observe the system as being interactive, with minimal delay between the user action and appropriate response for most types of operations.

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

The ingi and RIME non-LTR retrotransposons are not randomly distributed in the genome of Trypanosoma brucei - Bringaud,F.; Biteau,N.; Zuiderwijk,E.; Berriman,M.; El‐Sayed, Najib M.; Ghedin,E.; Melville,S. E.; Hall,N.; Baltz,T. (Molecular biology and evolution, 2004)

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

Interconnect Synthesis for Systems on Chip - Bhattacharyya, Shuvra S.; Bambha,N. K (MARYLAND UNIV COLLEGE PARK DEPT OF ELECTRICAL AND COMPUTER ENGINEERING, 2004)

Iterative record linkage for cleaning and integration - Bhattacharya,Indrajit; Getoor, Lise (Proceedings of the 9th ACM SIGMOD workshop on Research issues in data mining and knowledge discovery, 2004)
Record linkage, the problem of determining when two records refer to the same entity, has applications for both data cleaning (deduplication) and for integrating data from multiple sources. Traditional approaches use a similarity measure that compares tuples' attribute values; tuples with similarity scores above a certain threshold are declared to be matches. While this method can perform quite well in many domains, particularly domains where there is not a large amount of noise in the data, in some domains looking only at tuple values is not enough. By also examining the context of the tuple, i.e. the other tuples to which it is linked, we can come up with a more accurate linkage decision. But this additional accuracy comes at a price. In order to correctly find all duplicates, we may need to make multiple passes over the data; as linkages are discovered, they may in turn allow us to discover additional linkages. We present results that illustrate the power and feasibility of making use of join information when comparing records.
Keywords: clustering; deduplication; distance measure; record linkage

Java-through-c compilation: An enabling technology for java in embedded systems - Varma,A.; Bhattacharyya, Shuvra S. (Proceedings of the conference on Design, automation and test in Europe-Volume 3, 2004)

Low-dimensional embedding with extra information - Bǎdoiu,M.; Demaine,E. D; Hajiaghayi, Mohammad T.; Indyk,P. (Proceedings of the twentieth annual symposium on Computational geometry, 2004)

Managing the 802.11 energy/performance tradeoff with machine learning - Monteleoni,C.; Balakrishnan,H.; Feamster, Nick; Jaakkola,T. (Massachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory, 2004)
This paper addresses the problem of managing the tradeoff betweenenergy consumption and performance in wireless devices implementingthe IEEE 802.11 standard. To save energy, the 802.11 specificationproposes a power-saving mode (PSM), where a device can sleep to saveenergy, periodically waking up to receive packets from a neighbor(e.g., an access point) that may have buffered packets for thesleeping device. Previous work has shown that a fixed polling time forwaking up degrades the performance of Web transfers, because networkactivity is bursty and time-varying. We apply a new online machinelearning algorithm to this problem and show, using ns simulation andtrace analysis, that it is able to adapt well to network activity. Thelearning process makes no assumptions about the underlying networkactivity being stationary or even Markov. Our learning power-savingalgorithm, LPSM, guides the learning using a "loss function" thatcombines the increased latency from potentially sleeping too long andthe wasted use of energy in waking up too soon. In our nssimulations, LPSM saved 7%-20% more energy than 802.11 in power-savingmode, with an associated increase in average latency by a factor of1.02, and not more than 1.2. LPSM is straightforward to implementwithin the 802.11 PSM framework.

An MCMC-Based Particle Filter for Tracking Multiple Interacting Targets - Zia Khan; Balch, Tucker; Dellaert, Frank (Computer Vision - ECCV 2004, 2004)
We describe a Markov chain Monte Carlo based particle filter that effectively deals with interacting targets, i.e., targets that are influenced by the proximity and/or behavior of other targets. Such interactions cause problems for traditional approaches to the data association problem. In response, we developed a joint tracker that includes a more sophisticated motion model to maintain the identity of targets throughout an interaction, drastically reducing tracker failures. The paper presents two main contributions: (1) we show how a Markov random field (MRF) motion prior, built on the fly at each time step, can substantially improve tracking when targets interact, and (2) we show how this can be done efficiently using Markov chain Monte Carlo (MCMC) sampling. We prove that incorporating an MRF to model interactions is equivalent to adding an additional interaction factor to the importance weights in a joint particle filter. Since a joint particle filter suffers from exponential complexity in the number of tracked targets, we replace the traditional importance sampling step in the particle filter with an MCMC sampling step. The resulting filter deals efficiently and effectively with complicated interactions when targets approach each other. We present both qualitative and quantitative results to substantiate the claims made in the paper, including a large scale experiment on a video-sequence of over 10,000 frames in length.
Keywords: Artificial Intelligence (incl. Robotics); Computer Graphics; Image Processing and Computer Vision; pattern recognition

Measurement based optimal multi-path routing - Guven,T.; Kommareddy,C.; La,R.J.; Shayman,M.A.; Bhattacharjee, Bobby (INFOCOM 2004. Twenty-third AnnualJoint Conference of the IEEE Computer and Communications Societies, 2004)
We propose a new architecture for efficient network monitoring and measurements in a traditional IP network. This new architecture enables establishment of multiple paths (tunnels) between source-destination pairs without having to modify the underlying routing protocol(s). Based on the proposed architecture we propose a measurement-based multipath routing algorithm derived from simultaneous perturbation stochastic approximation. The proposed algorithm does not assume that the gradient of analytical cost function is known to the algorithm, but rather relies on noisy estimates from measurements. Using the analytical model presented in the paper we prove the convergence of the algorithm to the optimal solution. Simulation results are presented to demonstrate the advantages of the proposed algorithm under a variety of network scenarios. A comparative study with an existing optimal routing algorithm, MATE, is also provided
Keywords: algorithm; network; approximation; routing; IP; measurement; network; monitoring; optimization; perturbation; multipath; network; measurement-based; networks; Internet; optimisation; routing; processes; protocol; IP; protocols; stochastic; Routing; Stochastic

Multi-dimensional quorum sets for read-few write-many replica control protocols - Silaghi,B.; Keleher,P.; Bhattacharjee, Bobby (Cluster Computing and the Grid, 2004. CCGrid 2004. IEEE International Symposium on, 2004)
We describe d-spaces, a replica control protocol defined in terms of quorum sets on multi-dimensional logical structures. Our work is motivated by asymmetrical access patterns, where the number of read accesses to data are dominant relative to update accesses, i.e. where the protocols should be read-few write-many. D-spaces are optimal with respect to quorum group sizes. The quality of the tradeoff between read efficiency and update availability is not matched by existing quorum protocols. We also propose a novel scheme for implementing d-spaces that combines caching and local information to provide a best-effort form of global views. This allows quorum reconfiguration to be lightweight without impacting access latencies, even when the rate of membership changes is very high.
Keywords: accesses; availability; cache; caching; Communication; complexity; CONTROL; d-spaces; distributed; efficiency; lightweight; logical; multi-dimensional; processing; protocols; quorum; read; read-few; reconfiguration; replica; sets; storage; structures; update; write-many

Multiscale advanced raster map analysis system: definition, design and development - Patil,G. P.; Balbus,J.; Biging,G.; JaJa, Joseph F.; Myers,W. L.; Taillie,C. (Environmental and Ecological Statistics, 2004)
This paper brings together a multidisciplinary initiative to develop advanced statistical and computational techniques for analyzing, assessing, and extracting information from raster maps. This information will provide a rigorous foundation to address a wide range of applications including disease mapping, emerging infectious diseases, landscape ecological assessment, land cover trends and change detection, watershed assessment, and map accuracy assessment. It will develop an advanced map analysis system that integrates these techniques with an advanced visualization toolbox, and use the system to conduct large case studies using rich sets of raster data, primarily from remotely sensed imagery. As a result, it will be possible to study and evaluate raster maps of societal, ecological, and environmental variables to facilitate quantitative characterization and comparative analysis of geospatial trends, patterns, and phenomena. In addition to environmental and ecological studies, these techniques and tools can be used for policy decisions at national, state, and local levels, crisis management, and protection of infrastructure. Geospatial data form the foundation of an information-based society. Remote sensing has been a vastly under-utilized resource involving a multi-million dollar investment at the national levels. Even when utilized, the credibility has been at stake, largely because of lack of tools that can assess, visualize, and communicate accuracy and reliability in timely manner and at desired confidence levels. Consider an imminent 21st century scenario: What message does a multi-categorical map have about the large landscape it represents? And at what scale, and at what level of detail? Does the spatial pattern of the map reveal any societal, ecological, environmental condition of the landscape? And therefore can it be an indicator of change? How do you automate the assessment of the spatial structure and behavior of change to discover critical areas, hot spots, and their corridors? Is the map accurate? How accurate is it? How do you assess the accuracy of the map? How do we evaluate a temporal change map for change detection? What are the implications of the kind and amount of change and accuracy on what matters, whether climate change, carbon emission, water resources, urban sprawl, biodiversity, indicator species, human health, or early warning? And with what confidence? The proposed research initiative is expected to find answers to these questions and a few more that involve multi-categorical raster maps based on remote sensing and other geospatial data. It includes the development of techniques for map modeling and analysis using Markov Random Fields, geospatial statistics, accuracy assessment and change detection, upper echelons of surfaces, advanced computational techniques for geospatial data mining, and advanced visualization techniques.

New year’s resolutions for software quality - Basili, Victor R.; Boehm,B.; Davis,A.; Humphrey,W. S; Leveson,N.; Mead,N. R; Musa,J. D; Parnas,D. L; Pfleeger,S. L; Weyuker,E. (IEEE Software, 2004)
In the spirit of making resolutions for betterment in the New Year, ten distinguished individuals in the software quality field offer their recommendations on how organizations can improve software quality In the spirit of making resolutions for betterment in the New Year, ten distinguished individuals in the software quality field offer their recommendations on how organizations can improve software quality.

A Note on Efficient Computation of Haplotypes via Perfect Phylogeny - Bafna,Vineet; Gusfield,Dan; Hannenhalli, Sridhar; Yooseph,Shibu (Journal of Computational Biology, 2004)
The problem of inferring haplotype phase from a population of genotypes has received a lot of attention recently. This is partly due to the observation that there are many regions on human genomic DNA where genetic recombination is rare (Helmuth, 2001; Daly et al., 2001; Stephens et al., 2001; Friss et al., 2001). A Haplotype Map project has been announced by NIH to identify and characterize populations in terms of these haplotypes. Recently, Gusfield introduced the perfect phylogeny haplotyping problem, as an algorithmic implication of the no-recombination in long blocks observation, together with the standard population-genetic assumption of infinite sites. Gusfield's solution based on matroid theory was followed by direct θ(nm2 ) solutions that use simpler techniques (Bafna et al., 2003; Eskin et al., 2003), and also bound the number of solutions to the PPH problem. In this short note, we address two questions that were left open. First, can the algorithms of Bafna et al. (2003) and Eskin et al. (2003) be sped-up to O(nm + m2 ) time, which would imply an O(nm) time-bound for the PPH problem? Second, if there are multiple solutions, can we find one that is most parsimonious in terms of the number of distinct haplotypes.We give reductions that suggests that the answer to both questions is "no." For the first problem, we show that computing the output of the first step (in either method) is equivalent to Boolean matrix multiplication. Therefore, the best bound we can presently achieve is O(nmω–1), where ω ≤ 2.52 is the exponent of matrix multiplication. Thus, any linear time solution to the PPH problem likely requires a different approach. For the second problem of computing a PPH solution that minimizes the number of distinct haplotypes, we show that the problem is NP-hard using a reduction from Vertex Cover (Garey and Johnson, 1979).

Only in Europe?: The Economic and Military Foundations of European World Empires - Jordan Boyd-Graber (Typescript. Princeton University, 2004)

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

Pocket PhotoMesa: a Zoomable image browser for PDAs - Khella,A.; Bederson, Benjamin B. (Proceedings of the 3rd international conference on Mobile and ubiquitous multimedia, 2004)

Preschool children's use of mouse buttons - Hourcade,J. P; Bederson, Benjamin B.; Druin, Allison (CHI'04 extended abstracts on Human factors in computing systems, 2004)

Querying Web-Accessible Life Science Sources: Which paths to choose? - Bleiholder,J.; Naumann,F.; Raschid, Louiqa; Vidal,M. E (Proceedings of VLDB Workshop on Information Integration on the Web (IIWeb-2004), 2004)

A Rao-Blackwellized particle filter for EigenTracking - Zia Khan; Balch, T.; Dellaert, F. (Proceedings of the 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004. CVPR 2004, 2004)
Subspace representations have been a popular way to model appearance in computer vision. In Jepson and Black's influential paper on EigenTracking, they were successfully applied in tracking. For noisy targets, optimization-based algorithms (including EigenTracking) often fail catastrophically after losing track. Particle filters have recently emerged as a robust method for tracking in the presence of multi-modal distributions. To use subspace representations in a particle filter, the number of samples increases exponentially as the state vector includes the subspace coefficients. We introduce an efficient method for using subspace representations in a particle filter by applying Rao-Blackwellization to integrate out the subspace coefficients in the state vector. Fewer samples are needed since part of the posterior over the state vector is analytically calculated. We use probabilistic principal component analysis to obtain analytically tractable integrals. We show experimental results in a scenario in which we track a target in clutter.
Keywords: analytically tractable integrals; Computer vision; EigenTracking; Filters; Gaussian processes; modal analysis; multi-modal distributions; NOISE; noisy targets; optimisation; optimization-based algorithms; Particle filters; Particle measurements; Particle tracking; Principal component analysis; probabilistic principal component analysis; Rao-Blackwellized particle filter; Robustness; SHAPE; State estimation; state vector; subspace coefficients; Subspace representations; target tracking; vectors

Robotics & Automation Magazine Vol. 11 - Aliaga, D.G.; Allen,PK; Archibald,JK; Argyros,AA; Arkin,RC; Baker,C.; Baker, P.; Beard,RW; Bicchi,A.; Birgmajer,B.; others (IEEE Robotics & Automation Magazine, 2004)

Running on the bare metal with GeekOS - Hovemeyer, David; Hollingsworth, Jeffrey K; Bhattacharjee, Bobby (Proceedings of the 35th SIGCSE technical symposium on Computer science education, 2004)
Undergraduate operating systems courses are generally taught using one of two approaches: abstract or concrete. In the abstract approach, students learn the concepts underlying operating systems theory, and perhaps apply them using user-level threads in a host operating system. In the concrete approach, students apply concepts by working on a real operating system kernel. In the purest manifestation of the concrete approach, students implement operating system projects that run on real hardware.GeekOS is an instructional operating system kernel which runs on real hardware. It provides the minimum functionality needed to schedule threads and control essential devices on an x86 PC. On this foundation, we have developed projects in which students build processes, semaphores, a multilevel feedback scheduler, paged virtual memory, a filesystem, and inter-process communication. We use the Bochs emulator for ease of development and debugging. While this approach (tiny kernel run on an emulator) is not new, we believe GeekOS goes further towards the goal of combining realism and simplicity than previous systems have.
Keywords: education; emulation; Hardware; Operating systems

Scalable resilient media streaming - Banerjee,Suman; Lee,Seungjoon; Braud,Ryan; Bhattacharjee, Bobby; Srinivasan, Aravind (Proceedings of the 14th international workshop on Network and operating systems support for digital audio and video, 2004)
We present a low-overhead media streaming system, called SRMS (Scalable Resilient Media Streaming) that can be used to scalably deliver streaming data to a large group of receivers. SRMS uses overlay multicast for data distribution. to a large group of users. SRMS leverages a probabilistic loss recovery technique to provide high data delivery guarantees even under large network losses and overlay node failures. The clients in the SRMS system are able to interoperate with existing media streaming servers that use RTP for data transport. One of the interesting features of SRMS is that it can simultaneously support clients with disparate access bandwidths. It enables the necessary bandwidth adaptations using standard Real-time Transport Protocol (RTP) mechanisms, e.g. RTP translators. We have implemented and evaluated the SRMS system in detail on an emulated network as well as on a wide-area testbed with up to 128 clients. Our results show that clients using SRMS achieve high (97%) data delivery ratios with low overheads (<5%) even for a very dynamic network (up to five membership changes per minute).
Keywords: media streaming; Multicast; overlay network; Resilience

Self-Calibration from Image Derivatives - Brodskỳ, T.; Fermüller, Cornelia (International Journal of Computer Vision, 2004)

Sequencing Strategies for Parasite Genomes - Bartholomeu,D.; El‐Sayed, Najib M.; Melville,S. E. (METHODS IN MOLECULAR BIOLOGY-CLIFTON THEN TOTOWA-, 2004)

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

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

Slurpie: a cooperative bulk data transfer protocol - Sherwood,R.; Braud,R.; Bhattacharjee, Bobby (INFOCOM 2004. Twenty-third AnnualJoint Conference of the IEEE Computer and Communications Societies, 2004)
We present Slurpie: a peer-to-peer protocol for bulk data transfer. Slurpie is specifically designed to reduce client download times for large, popular files, and to reduce load on servers that serve these files. Slurpie employs a novel adaptive downloading strategy to increase client performance, and employs a randomized backoff strategy to precisely control load on the server. We describe a full implementation of the Slurpie protocol, and present results from both controlled local-area and wide-area testbeds. Our results show that Slurpie clients improve performance as the size of the network increases, and the server is completely insulated from large flash crowds entering the Slurpie network.
Keywords: adaptive; bulk; client-server; clients; computing; cooperative; data; data; downloading; network; peer-to-peer; protocol; protocols; Slurpie; strategy; systems; transfer; transport

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

Some foundational problems in interdomain routing - Feamster, Nick; Balakrishnan,H.; Rexford,J. (Proceedings of Third Workshop on Hot Topics in Networks (HotNets-III), 2004)
The substantial complexity of interdomain routing in theInternet comes from the need to support flexible poli- cies while scaling to a large number of Autonomous Systems. Despite impressive progress in characterizing the various ills of the Border Gateway Protocol (BGP), many problems remain unsolved, and the behavior of the routing system is still poorly understood. This paper argues that we must understand interdomain routing in terms of: (1) intrinsic properties and design tradeoffs of policy-based routing, independent of the specific routing protocol and (2) properties that relate to artifacts in to- day’s protocol. We pose open questions for the research community that, if answered, should help us understand why BGP’s many problems are so difficult to fix. Un- derstanding the fundamental properties of interdomain routing will help us decide how to make progress, be it making backward-compatible modifications to BGP or designing a radically different protocol.

Spiral acquisition of software-intensive systems of systems - Boehm,B.; Brown,A. W; Basili, Victor R.; Turner,R. (CrossTalk, 2004)

Structure from motion of parallel lines - Baker, P.; Aloimonos, J. (Computer Vision-ECCV 2004, 2004)

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

Systematic exploitation of data parallelism in hardware synthesis of DSP applications - Sen,M.; Bhattacharyya, Shuvra S. (Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, 2004)
We describe an approach that we have explored for low-power synthesis and optimization of image, video, and digital signal processing (DSP) applications. In particular, we consider the systematic exploitation of data parallelism across the operations of an application dataflow graph when synthesizing a dedicated hardware implementation. Data parallelism occurs commonly in DSP applications, and provides flexible opportunities to increase throughput or lower power consumption. Exploiting this parallelism in a dedicated hardware implementation comes at the expense of increased resource requirements, which must be balanced carefully when applying the technique in a design tool. We propose a high level synthesis algorithm to determine the data parallelism factor for each computation, and, based on the area and performance trade-off curve, design an efficient hardware representation of the dataflow graph. For performance estimation, our approach uses a cyclostatic dataflow intermediate representation of the hardware structure under synthesis. We then apply an automatic hardware generation framework to build the actual circuit.
Keywords: area-performance trade-off curve; automatic Verilog code generation; circuit optimisation; data flow graphs; data parallelism; dedicated hardware implementation synthesis; design tool; Digital signal processing; DSP applications; embedded systems; hardware description languages; hardware synthesis; high level synthesis; high level synthesis algorithm; IMAGE PROCESSING; PARALLEL PROCESSING; power consumption; Signal processing; synchronous dataflow graph; video processing

Systematic Integration of Parameterized Local Search Techniques in Evolutionary Algorithms - Bambha,N. K; Bhattacharyya, Shuvra S.; Teich,J.; Zitzler,E. (Genetic and Evolutionary Computation–GECCO 2004, 2004)

Toolkit design for interactive structured graphics - Bederson, Benjamin B.; Grosjean,J.; Meyer,J. (Software Engineering, IEEE Transactions on, 2004)

Trust-preserving set operations - Morselli,R.; Bhattacharjee, Bobby; Katz, Jonathan; Keleher,P. (INFOCOM 2004. Twenty-third AnnualJoint Conference of the IEEE Computer and Communications Societies, 2004)
We describe a method for performing trust-preserving set operations by untrusted parties. Our motivation for this is the problem of securely reusing content-based search results in peer-to-peer networks. We model search results and indexes as data sets. Such sets have value for answering a new query only if they are trusted. In the absence of any system-wide security mechanism, a data set is trusted by a node a only if it was generated by some node which is trusted by a. Our main contributions are a formal definition of the problem as well as an efficient scheme that solves this problem by allowing untrusted peers to perform set operations on trusted data sets while also producing unforgeable proofs of correctness. This is accomplished by requiring trusted nodes to sign appropriately-defined digests of generated sets; each such digest consists of an RSA accumulator and a Bloom filter. The scheme is general, and has other applications as well. We give an analysis demonstrating the low overhead of the scheme, and we include experimental data which confirm the analysis.
Keywords: accumulator; Bloom; computing; filter; mechanism; network; operation; peer-to-peer; RSA; Security; security; set; system-wide; Telecommunication; theory; trust-preserving

Unsupervised sense disambiguation using bilingual probabilistic models - Bhattacharya,Indrajit; Getoor, Lise; Bengio,Yoshua (Proceedings of the 42nd Annual Meeting on Association for Computational Linguistics, 2004)
We describe two probabilistic models for unsupervised word-sense disambiguation using parallel corpora. The first model, which we call the Sense model, builds on the work of Diab and Resnik (2002) that uses both parallel text and a sense inventory for the target language, and recasts their approach in a probabilistic framework. The second model, which we call the Concept model, is a hierarchical model that uses a concept latent variable to relate different language specific sense labels. We show that both models improve performance on the word sense disambiguation task over previous unsupervised approaches, with the Concept model showing the largest improvement. Furthermore, in learning the Concept model, as a by-product, we learn a sense inventory for the parallel language.

Using Trust in Recommender Systems: An Experimental Analysis - Massa,Paolo; Bhattacharjee, Bobby (Trust ManagementTrust Management, 2004)
Recommender systems (RS) have been used for suggesting items (movies, books, songs, etc.) that users might like. RSs compute a user similarity between users and use it as a weight for the users’ ratings. However they have many weaknesses, such as sparseness, cold start and vulnerability to attacks. We assert that these weaknesses can be alleviated using a Trust-aware system that takes into account the “web of trust” provided by every user. Specifically, we analyze data from the popular Internet web site epinions.com . The dataset consists of 49290 users who expressed reviews (with rating) on items and explicitly specified their web of trust, i.e. users whose reviews they have consistently found to be valuable. We show that any two users have usually few items rated in common. For this reason, the classic RS technique is often ineffective and is not able to compute a user similarity weight for many of the users. Instead exploiting the webs of trust, it is possible to propagate trust and infer an additional weight for other users. We show how this quantity can be computed against a larger number of users.
Keywords: Computer; Science

Verifying the Correctness of Wide-Area Internet Routing - Feamster, Nick; Balakrishnan,Hari (Massachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory, 2004)
Several studies have shown that wide-area Internet routing is fragile, with failures occurring for a variety of reasons. Routing fragility is largely due to the flexible and powerful ways in which BGP can be configured to perform various tasks, which range from implementing the policies of commercial relationships to configuring backup paths. Configuring routers in an AS is like writing a distributed program, and BGP's flexible configuration and today's relatively low-level configuration languages make the process error-prone. The primary method used by operators to determine whether their complex configurations are correct is to try them out in operation.We believe that there is a need for a systematic approach to verifying router configurations before they are deployed. This paper develops a static analysis framework for configuration checking, and uses it in the design of rcc, a ``router configuration checker''. rcc takes as input a set of router configurations and flags anomalies and errors, based on a set of well-defined correctness conditions. We have used rcc to check BGP configurations from 9 operational networks, testing nearly 700 real-world router configurations in the process. Every network we analyzed had configuration errors, some of which were potentially serious and had previously gone unnoticed. Our analysis framework and results also suggest ways in which BGP and configuration languages should be improved. rcc has also been downloaded by 30 network operators to date.

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

Visualization and analysis of microarray and gene ontology data with treemaps - Baehrecke,Eric H; Dang,Niem; Babaria,Ketan; Shneiderman, Ben (BMC Bioinformatics, 2004)
The increasing complexity of genomic data presents several challenges for biologists. Limited computer monitor views of data complexity and the dynamic nature of data in the midst of discovery increase the challenge of integrating experimental results with information resources. The use of Gene Ontology enables researchers to summarize results of quantitative analyses in this framework, but the limitations of typical browser presentation restrict data access.

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

Web search intent induction via automatic query reformulation - Daumé, Hal; Brill,E. (Proceedings of HLT-NAACL 2004: Short Papers on XX, 2004)

What works better for question answering: Stemming or morphological query expansion - Bilotti,M. W; Katz,B.; Jimmy Lin (Proceedings of the Information Retrieval for Question Answering (IR4QA) Workshop at SIGIR 2004, 2004)
How do different information retrieval techniques affect theperformance of document retrieval in the context of question answering? An exploration of this question is our overall re- search goal. In this paper, we specifically examine strategies for coping with morphological variation. This work quanti- tatively compares two different approaches to handling term variation: applying a stemming algorithm at indexing time, and performing morphological query expansion at retrieval time. We discovered that, compared to the no-stemming baseline, stemming results in lower recall, and morphologi- cal expansion yields higher recall. By separately weighting different term variants, we were able to achieve even higher recall, which opens the door to interesting question analy- sis algorithms for sophisticated query generation. Another significant contribution of our work is the development of a reusable question answering test collection to support our experiments.

Accessing diverse geo-referenced data sources with the SAND spatial DBMS - Sankaranarayanan,Jagan; Tanin,Egemen; Samet, Hanan; Brabec,Frantisek (Proceedings of the 2003 annual national conference on Digital government research, 2003)
The Internet has become the most frequently accessed medium for obtaining various types of data. In particular, government agencies, academic institutions, and private enterprises have published gigabytes of geo-referenced data on the Web. However, to obtain geo-referenced data from the Web successfully, systems must be designed to be capable of understanding the data sets published in different data formats. Also, even if the data sets are available in a simple known format, they often have poorly defined structures. With these issues in mind, we have developed an Internet-enabled data collection and conversion utility that interfaces with our prototype spatial database system, SAND. Using this utility, data can be retrieved from many different sources on the Web and converted into a format understandable by the SAND spatial database management system. Our collection and conversion utility is able to import the most popular data formats; namely, ESRI Shapefiles, Microsoft Excel files, HTML files, and GML files. Data in unstructured formats are verified for correct selection of the data types and handling of missing tuples before the insertion operation into the database. Moreover, our utility makes it possible to download any nonspatial data set and combine it internally with a relevant spatial data set. These features are accessible through a spreadsheet-like interface for online editing and structuring of data.

Accuracy, Target Reentry and Fitts’ Law Performance of Preschool Children Using Mice - Hourcade,J. P; Bederson, Benjamin B.; Druin, Allison; Guimbretiere,F. (University of Maryland Technical Report, HCIL-2003, 2003)

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

Automatic classification of multi-word expressions in print dictionaries - Geyken,Alexander; Jordan Boyd-Graber (Lingvisticae Investigationes, 2003)
SummaryThis work demonstrates the assignment of multi-word expressions in print dictionaries to POS classes with minimal linguistic resources. In this application, 32,000 entries from the Wörterbuch der deutschen Idiomatik (H. Schemann 1993) were classified using an inductive description of POS sequences in conjunction with a Brill Tagger trained on manually tagged idiomatic entries. This process assigned categories to 86% of entries with 88% accuracy. This classification supplies a meaningful preprocessing step for further applications: the resulting POS-sequences for all idiomatic entries might be used for the automatic recognition of multi-word lexemes in unrestricted text.

Automatic thumbnail cropping and its effectiveness - Suh,Bongwon; Ling,Haibin; Bederson, Benjamin B.; Jacobs, David W. (Proceedings of the 16th annual ACM symposium on User interface software and technology, 2003)
Thumbnail images provide users of image retrieval and browsing systems with a method for quickly scanning large numbers of images. Recognizing the objects in an image is important in many retrieval tasks, but thumbnails generated by shrinking the original image often render objects illegible. We study the ability of computer vision systems to detect key components of images so that automated cropping, prior to shrinking, can render objects more recognizable. We evaluate automatic cropping techniques 1) based on a general method that detects salient portions of images, and 2) based on automatic face detection. Our user study shows that these methods result in small thumbnails that are substantially more recognizable and easier to find in the context of visual search.
Keywords: Face detection; image cropping; saliency map; thumbnail; usability study; visual search; zoomable user interfaces

Automatic thumbnail cropping and its effectiveness - Suh,B.; Ling,H.; Bederson, Benjamin B.; Jacobs, David W. (Proceedings of the 16th annual ACM symposium on User interface software and technology, 2003)

Bootstrapping security associations for routing in mobile ad-hoc networks - Bobba,R. B; Eschenauer,L.; Gligor,V.; Arbaugh, William A. (IEEE Global Telecommunications Conference, 2003. GLOBECOM '03, 2003)
To date, most solutions proposed for secure routing in mobile ad-hoc networks (MANETs), assume that secure associations between pairs of nodes can be established on-line; e.g., by a trusted third party, by distributed trust establishment. However, establishing such security associations, with or without trusted third parties, requires reliance on routing layer security. In this paper, we eliminate this apparent cyclic dependency between security services and secure routing in MANETs and show how to bootstrap security for the routing layer. We use the notion of statistically unique and cryptographically verifiable (SUCV) identifiers to implement a secure binding between IP addresses and keys that is independent of any trusted security service. We illustrate our solution with the dynamic source routing (DSR) protocol and compare it with other solutions for secure routing.
Keywords: ad hoc networks; bootstrapping security association; Cryptographic protocols; dynamic source routing protocol; Fabrics; Intelligent networks; IP address; IP key; IP networks; Message authentication; mobile ad-hoc network; mobile radio; Protection; Public key; public key cryptography; routing layer security reliability; routing protocols; secure routing; Security; security service; statistically unique cryptographically verification; telecommunication security

Bringing Treasures to the Surface: Previews and Overviews in a Prototype for the Library of Congress National Digital Library - Marchionini,A.S.; Nation,D.; Karasik,S.; Cronnell,T.; Shneiderman, Ben; Spotfire,V.D.M.U.; Bederson, Benjamin B.; Data,T.S.; Hochheiser,H.; Shneiderman, Ben; others (The craft of information visualization: readings and reflections, 2003)

Broadening Access to Large Online Databases by Generalizing Query Previews - Tanin,Egemen; Plaisant, Catherine; Shneiderman, Ben (The Craft of Information VisualizationThe Craft of Information Visualization, 2003)
Companies, government agencies, and other types of organizations are making their large databases available to the world over the Internet. Current database front-ends do not give users information about the distribution of data. This leads many users to waste time and network resources posing queries that have either zero-hit or mega-hit result sets. Query previews form a novel visual approach for browsing large databases. Query previews supply data distribution information about the database that is being searched and give continuous feedback about the size of the result set for the query as it is being formed. On the other hand, query previews use only a few pre-selected attributes of the database. The distribution information is displayed only on these attributes. Unfortunately, many databases are formed of numerous relations and attributes. This paper introduces a generalization of query previews. We allow users to browse all of the relations and attributes of a database using a hierarchical browser. Any of the attributes can be used to display the distribution information, making query previews applicable to many public online databases.

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)

Construction of an efficient overlay multicast infrastructure for real-time applications - Banerjee,S.; Kommareddy,C.; Kar,K.; Bhattacharjee, Bobby; Khuller, Samir (INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications. IEEE Societies, 2003)
This paper presents an overlay architecture where service providers deploy a set of service nodes (called MSNs) in the network to efficiently implement media-streaming applications. These MSNs are organized into an overlay and act as application-layer multicast forwarding entities for a set of clients. We present a decentralized scheme that organizes the MSNs into an appropriate overlay structure that is particularly beneficial for real-time applications. We formulate our optimization criterion as a "degree-constrained minimum average-latency problem" which is known to be NP-hard. A key feature of this formulation is that it gives a dynamic priority to different MSNs based on the size of its service set. Our proposed approach iteratively modifies the overlay tree using localized transformations to adapt with changing distribution of MSNs, clients, as well as network conditions. We show that a centralized greedy approach to this problem does not perform quite as well, while our distributed iterative scheme efficiently converges to near-optimal solutions.
Keywords: application-layer; applications; communication; criterion; decentralized; distributed; entities; forwarding; infrastructure; Internet; iterative; media-streaming; methods; MSN; Multicast; nodes; NP-hard; OPTIMIZATION; overlay; real; real-time; scheme; service; systems; TIME

Cooperative peer groups in NICE - Lee,S.; Sherwood,R.; Bhattacharjee, Bobby (INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications. IEEE Societies, 2003)
A distributed scheme for trust inference in peer-to-peer networks is presented. Our work is in context of the NICE system, which is a platform for implementing cooperative applications over the Internet. We describe a technique for efficiently storing user reputation information in a completely decentralized manner, and show how this information can be used to efficiently identify noncooperative users in NICE. We present a simulation based study of our algorithms, in which we show our scheme scales to thousands of users using modest amounts of storage, processing, and bandwidth at any individual node. Lastly, we show that our scheme is robust and can form cooperative groups in systems where the vast majority of users are malicious.
Keywords: algorithm; cooperative; decentralized; distributed; identification; individual; inference; inference; information; Internet; malicious; manner; mechanisms; networks; NICE; node; noncooperative; peer-to-peer; platform; reputation; retrieval; storage; system; trust; users; users

The craft of information visualization: readings and reflections - Bederson, Benjamin B.; Shneiderman, Ben (Morgan Kaufmann, 2003)
Since the beginning of the computer age, researchers from many disciplines have sought to facilitate people's use of computers and to provide ways for scientists to make sense of the immense quantities of data coming out of them. One gainful result of these efforts has been the field of information visualization, whose technology is increasingly applied in scientific research, digital libraries, data mining, financial data analysis, market studies, manufacturing production control, and data discovery.This book collects 38 of the key papers on information visualization from a leading and prominent research lab, the University of Maryland's Human-Computer Interaction Lab (HCIL). Celebrating HCIL's 20th anniversary, this book presents a coherent body of work from a respected community that has had many success stories with its research and commercial spin-offs. Each chapter contains an introduction specifically written for this volume by two leading HCI researchers, to describe the connections among those papers and reveal HCIL's individual approach to developing innovations.*Presents key ideas, novel interfaces, and major applications of information visualization tools, embedded in inspirational prototypes.*Techniques can be widely applied in scientific research, digital libraries, data mining, financial data analysis, business market studies, manufacturing production control, drug discovery, and genomic studies.*Provides an "insider" view to the scientific process and evolution of innovation, as told by the researchers themselves.*This work comes from the prominent and high profile University of Maryland's Human Computer Interaction Lab
Keywords: Computers / Computer Graphics; Computers / Computer Science; Computers / Digital Media / Desktop Publishing; Computers / General; Computers / Social Aspects / Human-Computer Interaction; Computers / User Interfaces; Human-computer interaction; Information Visualization; Science / General; User-centered system design

Critical fields and pulse durations for precessional switching of thin magnetic films - Bertotti,G.; Mayergoyz, Issak D; Serpico,C. (Magnetics, IEEE Transactions on, 2003)
The precessional switching process of a uniformly magnetized thin film with in-plane anisotropy subject to pulsed magnetic fields applied in the film plane is analyzed. Critical fields required to achieve switching are studied for the case when the applied field is constant during the pulse duration and forms arbitrary angles with the hard axis. By using two integrals of magnetization motion, the explicit expressions for the critical field are derived. The formulas for durations of rectangular magnetic field pulses that guarantee the precessional switching of magnetization are presented as well.
Keywords: anisotropy; axis; critical; durations; field; fields; film; films; hard; in-plane; integrals; magnetic; magnetisation; magnetization; magnetization; magnetized; motion; precessional; pulse; pulsed; rectangular; reversal; switching; thin; uniformly

DART: a framework for regression testing "nightly/daily builds" of GUI applications - Memon, Atif M.; Banerjee,I.; Hashmi,N.; Nagarajan,A. (Software Maintenance, 2003. ICSM 2003. Proceedings. International Conference on, 2003)
"Nightly/daily building and smoke testing" have become widespread since they often reveal bugs early in the software development process. During these builds, software is compiled, linked, and (re)tested with the goal of validating its basic functionality. Although successful for conventional software, smoke tests are difficult to develop and automatically rerun for software that has a graphical user interface (GUI). In this paper, we describe a framework called DART (daily automated regression tester) that addresses the needs of frequent and automated re-testing of GUI software. The key to our success is automation: DART automates everything from structural GUI analysis; test case generation; test oracle creation; to code instrumentation; test execution; coverage evaluation; regeneration of test cases; and their re-execution. Together with the operating system's task scheduler, DART can execute frequently with little input from the developer/tester to retest the GUI software. We provide results of experiments showing the time taken and memory required for GUI analysis, test case and test oracle generation, and test execution. We also empirically compare the relative costs of employing different levels of detail in the GUI test cases.
Keywords: automated retesting; automatic test software; coverage evaluation; daily automated regression tester; DART; frequent retesting; graphical user interface; Graphical user interfaces; GUI software; instrumentation coding; program testing; regression testing; Software development management; Software development process; Software maintenance; Software quality; structural GUI analysis; Test Case Generation; test cases regeneration; Test execution; test oracle creation

Data partitioning for DSP software synthesis - Ko,M. Y; Bhattacharyya, Shuvra S. (Lecture Notes in Computer Science, 2003)

Data Structures, Optimal Choice of Parameters, and Complexity Results for Generalized Multilevel Fast Multipole Methods in $d$ Dimensions - Gumerov, Nail A.; Duraiswami, Ramani; Borovikov,Eugene A. (Technical Reports from UMIACS UMIACS-TR-2003-28, 2003)
We present an overview of the Fast Multipole Method, explain the use ofoptimal data structures and present complexity results for the algorithm. We explain how octree structures and bit interleaving can be simply used to create efficient versions of the multipole algorithm in $d$ dimensions. We then present simulations that demonstrate various aspects of the algorithm, including optimal selection of the clustering parameter, the influence of the error bound on the complexity, and others. The use of these optimal parameters results in a many-fold speed-up of the FMM, and prove very useful in practice. UMIACS-TR-2003-28
Keywords: Technical Report

A Deductive Database Approach to AI Planning - Brogi,A.; V.S. Subrahmanian; Zaniolo,C. (Journal of Intelligent Information Systems, 2003)
In this paper, we show that the classical A.I. planning problem can be modelled using simple database constructs with logic-based semantics. The approach is similar to that used to model updates and nondeterminism in active database rules. We begin by showing that planning problems can be automatically converted to Datalog1S programs with nondeterministic choice constructs, for which we provide a formal semantics using the concept of stable models. The resulting programs are characterized by a syntactic structure (XY-stratification) that makes them amenable to efficient implementation using compilation and fixpoint computation techniques developed for deductive database systems. We first develop the approach for sequential plans, and then we illustrate its flexibility and expressiveness by formalizing a model for parallel plans, where several actions can be executed simultaneously. The characterization of parallel plans as partially ordered plans allows us to develop (parallel) versions of partially ordered plans that can often be executed faster than the original partially ordered plans.

Defeating Web censorship with untrusted messenger discovery - Feamster, Nick; Balazinska,M.; Wang,W.; Balakrishnan,H.; Karger,D. (Workshop on Privacy Enhancing Technologies, 2003)

Deno: a decentralized, peer-to-peer object-replication system for weakly connected environments - Cetintemel,U.; Keleher,P. J; Bhattacharjee, Bobby; Franklin,M.J. (Computers, IEEE Transactions on, 2003)
This paper presents the design, implementation, and evaluation of the replication framework of Deno, a decentralized, peer-to-peer object-replication system targeted for weakly connected environments. Deno uses weighted voting for availability and pair-wise, epidemic information flow for flexibility. This combination allows the protocols to operate with less than full connectivity, to easily adapt to changes in group membership, and to make few assumptions about the underlying network topology. We present two versions of Deno's protocol that differ in the consistency levels they support. We also propose security extensions to handle a class of malicious actions that involve misrepresentation of protocol information. Deno has been implemented and runs on top of Linux and Win32 platforms. We use the Deno prototype to characterize the performance of the Deno protocols and extensions. Our study reveals several interesting results that provide fundamental insight into the benefits of decentralization and the mechanics of epidemic protocols.
Keywords: actions; connected; consistency; data; data; databases; decentralized; Deno; distributed; environments; epidemic; group; levels; Linux; malicious; management; membership; network; object; object-replication; of; operating; peer-to-peer; protocols; replicated; replication; Security; security; synchronisation; system; systems; topology; Unix; voting; weakly; weighted; Win32

Design Considerations for Optically Connected Systems on Chip - Bhattacharyya, Shuvra S.; Bambha,N. K; Euliss,G. (MARYLAND UNIV COLLEGE PARK DEPT OF ELECTRICAL AND COMPUTER ENGINEERING, 2003)

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.

Digital government - Marchionini,G.; Samet, Hanan; Brandt,L. (Communications of the ACM, 2003)
Information technologies are being applied vigorously by governmental units at national,regional, and local levels around the world. The application of IT to government service is often termed “e-government” and the larger concept of government that depends upon IT to achieve basic missions is termed “digital government.” This distinction is, of course, lexically arbitrary, but serves to distinguish R&D specifically aimed at creating techniques for applying IT to government operations. Such R&D efforts also consider the long-term impact of these applications on citizens and government itself.

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.

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)

Driving scientific applications by data in distributed environments - Saltz, J.; Catalyurek,U.; Kurc, T.; Gray,M.; Hastings,S.; Langella,S.; Narayanan,S.; Martino,R.; Bryant,S.; Peszynska,M.; others (Computational Science—ICCS 2003, 2003)

Dynamic querying for pattern identification in microarray and genomic data - Hochheiser,H.; Baehrecke,E. H; Mount, Stephen M.; Shneiderman, Ben (2003 International Conference on Multimedia and Expo, 2003. ICME '03. Proceedings, 2003)
Data sets involving linear ordered sequences are a recurring theme in bioinformatics. Dynamic query tools that support exploration of these data sets can be useful for identifying patterns of interest. This paper describes the use of one such tool - timesearcher - to interactively explore linear sequence data sets taken from two bioinformatics problems. Microarray time course data sets involve expression levels for large numbers of genes over multiple time points. Timesearcher can be used to interactively search these data sets for genes with expression profiles of interest. The occurrence frequencies of short sequences of DNA in aligned exons can be used to identify sequences that play a role in the pre-mRNA splicing. Timesearcher can be used to search these data sets for candidate splicing signals.
Keywords: Bioinformatics; data sets; Displays; dynamic querying; expression profiles; Frequency; Gene expression; genes; Genetics; genomic data; Genomics; linear ordered sequences; macromolecules; medical signal processing; Mice; Microarray; pattern identification; pattern recognition; premRNA splicing; Query processing; sequences; Signal processing; splicing; TimeSearcher

Dynamic rebinding for marshalling and update, with destruct-time ? - Bierman,Gavin; Hicks, Michael W.; Sewell,Peter; Stoyle,Gareth; Wansbrough,Keith (Proceedings of the eighth ACM SIGPLAN international conference on Functional programming, 2003)
Most programming languages adopt static binding, but for distributed programming an exclusive reliance on static binding is too restrictive: dynamic binding is required in various guises, for example when a marshalled value is received from the network, containing identifiers that must be rebound to local resources. Typically it is provided only by ad-hoc mechanisms that lack clean semantics.In this paper we adopt a foundational approach, developing core dynamic rebinding mechanisms as extensions to simply-typed call-by-value ? -calculus. To do so we must first explore refinements of the call-by-value reduction strategy that delay instantiation, to ensure computations make use of the most recent versions of rebound definitions. We introduce redex-time and destruct-time strategies. The latter forms the basis for a ?marsh calculus that supports dynamic rebinding of marshalled values, while remaining as far as possible statically-typed. We sketch an extension of ? marsh with concurrency and communication, giving examples showing how wrappers for encapsulating untrusted code can be expressed. Finally, we show that a high-level semantics for dynamic updating can also be based on the destruct-time strategy, defining a ?marsh calculus with simple primitives to provide type-safe updating of running code. We thereby establish primitives and a common semantic foundation for a variety of real-world dynamic rebinding requirements.
Keywords: distributed programming; dynamic binding; dynamic update; lambda calculus; marshalling; programming languages; serialisation

Efficient particle filter-based tracking of multiple interacting targets using an MRF-based motion model - Zia Khan; Balch, T.; Dellaert, F. (2003 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2003. (IROS 2003). Proceedings, 2003)
We describe a multiple hypothesis particle filter for tracking targets that are influenced by the proximity and/or behavior of other targets. Our contribution is to show how a Markov random field motion prior, built on the fly at each time step, can model these interactions to enable more accurate tracking. We present results for a social insect tracking application, where we model the domain knowledge that two targets cannot occupy the same space, and targets actively avoid collisions. We show that using this model improves track quality and efficiency. Unfortunately, the joint particle tracker we propose suffers from exponential complexity in the number of tracked targets. An approximation to the joint filter, however, consisting of multiple nearly independent particle filters can provide similar track quality at substantially lower computational cost.
Keywords: collision avoidance; computational cost; Computational efficiency; Educational institutions; exponential complexity; Filtering; filtering theory; Insects; joint particle tracker; Markov processes; Markov random field motion; Markov random fields; multiple interacting targets; particle filter-based tracking; Particle filters; Particle tracking; Radar tracking; social insect tracking application; target tracking; Trajectory

Efficient peer-to-peer searches using result-caching - Bhattacharjee, Bobby; Chawathe,S.; Gopalakrishnan,V.; Keleher,P.; Silaghi,B. (Peer-to-Peer Systems II, 2003)
Existing peer-to-peer systems implement a single function well: data lookup. There is now a wealth of research describing how to reliably disseminate, and to later retrieve, data in a scalable and load-balanced manner.

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

Electronic voting system usability issues - Bederson, Benjamin B.; Lee,B.; Sherman,R.M.; Herrnson,P.S.; Niemi,R.G. (Proceedings of the SIGCHI conference on Human factors in computing systems, 2003)

Energy reduction techniques for multimedia applications with tolerance to deadline misses - Hua,S.; Qu,G.; Bhattacharyya, Shuvra S. (Proceedings of the 40th annual Design Automation Conference, 2003)

Energy-efficient broadcast and multicast trees for reliable wireless communication - Banerjee,S.; Misra,A.; Yeo,Jihwang; Agrawala, Ashok K. (Wireless Communications and Networking, 2003. WCNC 2003. 2003 IEEE, 2003)
We define energy-efficient broadband and multicast schemes for reliable communication in multi-hop wireless networks. Unlike previous techniques, the choice of neighbors in the broadband and multicast trees in these schemes, are based not only on the link distance, but also on the error rates associated with the link. Our schemes can be implemented using both positive and negative acknowledgement based reliable broadcast techniques in the link layer. Through simulations, we show that our scheme achieves up to 45% improvement over previous schemes on realistic 100-node network topologies. A positive acknowledgment based implementation is preferred. Our simulations show that the additional benefits of a positive acknowledgement based implementation is marginal (1-2%). Therefore a negative acknowledgement based implementation of our schemes is equally applicable in constructing energy-efficient reliable and multicast data delivery paths.
Keywords: broadcast; channels; multicast; communication; broadcast; communication; network; data; delivery; energy-efficient; layer; multicast; network; networks; network; networks; telecommunication; paths; multicast; rates; link; reliability; topologies; wireless; topology; radio; trees; error; trees; multihop; wireless

Experimental validation of new software technology - Zelkowitz, Marvin V; Wallace,D. R; Binkley,D. W (SERIES ON SOFTWARE ENGINEERING AND KNOWLEDGE ENGINEERING, 2003)
When to apply a new technology in an organization is acritical decision for every software development organization. Earlier work defines a set of methods that the research community uses when a new technology is developed. This chapter presents a discussion of the set of methods that industrial organizations use before adopting a new technology. First there is a brief definition of the earlier research methods and then a definition of the set of industrial methods. A comparison of the two sets leads into the perspectives of these methods of experts in the research and industrial community via surveys made to those communities.

Exploring the probabilistic design space of multimedia systems - Shaoxiong Hua; Gang Qu; Bhattacharyya, Shuvra S. (14th IEEE International Workshop on Rapid Systems Prototyping, 2003. Proceedings, 2003)
In this paper, we propose the novel concept of probabilistic design for multimedia systems and a methodology to quickly explore such design space at an early design stage. The probabilistic design is motivated by the challenge of how to design, but not over-design, multimedia embedded systems while systematically incorporating such application's performance requirements, uncertainties in execution time, and tolerance for reasonable execution failures. Our goal is to bridge the gap between real-time analysis and embedded software implementation for rapid and economic (multimedia) system prototyping. Our method takes advantage of multimedia system's unique features mentioned above to relax the rigid hardware requirements for software implementation and eventually avoid over-designing the system.
Keywords: economic system prototyping; embedded software implementation; Embedded system; Energy consumption; execution time uncertainties; Hardware; multimedia embedded systems; multimedia system prototyping; multimedia systems; performance requirements; probabilistic design space; rapid system prototyping; Real time systems; real-time analysis; reasonable execution failure tolerance; Resource management; software prototyping; Space exploration; Streaming media; systems analysis; Timing; Uncertainty

Family Calendar Survey - Hutchinson,Hilary; Bederson, Benjamin B.; Plaisant, Catherine; Druin, Allison (Technical Reports from UMIACS, 2003)
Beginning in late July 2002, we conducted a survey about people's personal andfamily calendaring habits. By the end of September, we had over 400 responses, which are summarized below. The survey was conducted to help inform our work in designing new technologies for families, motivated in part by our work on the interLiving project. InterLiving is a 3 year, European Union-funded project where we work with distributed, multi-generational families as design partners to create new technologies (see http://www.cs.umd.edu/hcil/interliving for details). The survey was administered from a web page (https://www.cs.umd.edu/users/hilary/survey/survey.htm), and participants were solicited via a "chain-mail" email approach. We began by sending a request to fill out a survey to our friends, families, and colleagues. We asked that they forward the request on to their friends, family and colleagues as well. While we realize that this was an imperfect approach, we believed that the respondents would be representative of the users we are initially targeting in our research on family calendaring and coordination - individuals who are already making relatively heavy use of computers at home and/or work. The results seem to validate this assumption. Many of our respondents likely come from the HCI community as the mailing went to our large lab mailing list. We may have some pollution in the data as a result of people in the same household (e.g. husband and wife) both filling out the survey. Despite these issues, the results we got were helpful in eliciting a number of important findings, namely that people rely on multiple calendars, many of which are still paper. (UMIACS-TR-2002-92) (HCIL-TR-2002-21)
Keywords: Technical Report

Formalizing dynamic software updating - Bierman,G.; Hicks, Michael W.; Sewell,P.; Stoyle,G. (Proceedings of the Second International Workshop on Unanticipated Software Evolution (USE), 2003)
Dynamic software updating (DSU) enables running programs to beupdated with new code and data without interrupting their execution. A number of DSU systems have been designed, but there is still little rig- orous understanding of how to use DSU technology so that updates are safe. As a first step in this direction, we introduce a small update calculus with a precise mathematical semantics. The calculus is formulated as an extension of a typed lambda calculus, and supports updating technology similar to that of the programming language Erlang [2]. Our goal is to provide a simple yet expressive foundation for reasoning about dynam- ically updateable software. In this paper, we present the details of the calculus, give some examples of its expressive power, and discuss how it might be used or extended to guarantee safety properties.

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.

Geometrical analysis of precessional switching and relaxation in uniformly magnetized bodies - Bertotti,G.; Mayergoyz, Issak D; Serpico,C.; d'Aquino,M. (Magnetics, IEEE Transactions on, 2003)
Precessional switching and relaxation in a single-domain particle or film is studied by using the Landau-Lifshitz-Gilbert equation. The analysis of the switching process is based on the explicit knowledge of two integrals of motion for the magnetization dynamics in the conservative case. The knowledge of these integrals of motions enables one to carry out the geometrical analysis of the system and give the complete phase portrait. The relaxation process which occurs after the magnetization is reversed is analyzed by using geometrical methods and it is showed that the dynamical system exhibits entanglement of separatrices and riddled basins of attraction.
Keywords: analysis; attraction; basins; bodies; dynamical; dynamics; entanglement; equation; film; films; geometrical; integrals; Landau-Lifshitz-Gilbert; magnetic; magnetisation; magnetization; magnetized; motion; of; particle; particles; phase; portrait; precessional; relaxation; reversal; riddled; separatrices; single-domain; spin; switching; system; thin; uniformly

Goal-Driven Reconfiguration of Polymorphous Architectures - Lohani,S.; Bhattacharyya, Shuvra S. (Domain-specific processors: systems, architectures, modeling, and simulation, 2003)

GUI ripping: Reverse engineering of graphical user interfaces for testing - Memon, Atif M.; Banerjee,I.; Nagarajan,A. (Proceedings of the 10th working conference on reverse engineering (WCRE’03), 2003)
Graphical user interfaces (GUIs) are important parts oftoday’s software and their correct execution is required to ensure the correctness of the overall software. A popular technique to detect defects in GUIs is to test them by exe- cuting test cases and checking the execution results. Test cases may either be created manually or generated auto- matically from a model of the GUI. While manual testing is unacceptably slow for many applications, our experience with GUI testing has shown that creating a model that can be used for automated test case generation is difficult. We describe a new approach to reverse engineer a model represented as structures called a GUI forest, event-flow graphs and an integration tree directly from the executable GUI. We describe “GUI Ripping”, a dynamic process in which the software’s GUI is automatically “traversed” by opening all its windows and extracting all their widgets (GUI objects), properties, and values. The extracted infor- mation is then verified by the test designer and used to auto- matically generate test cases. We present algorithms for the ripping process and describe their implementation in a tool suite that operates on Java and Microsoft Windows’ GUIs. We present results of case studies which show that our approach requires very little human intervention and is es- pecially useful for regression testing of software that is mod- ified frequently. We have successfully used the “GUI Rip- per” in several large experiments and have made it avail- able as a downloadable tool.

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 high performance multi-perspective vision studio - Borovikov,Eugene; Sussman, Alan (Proceedings of the 17th annual international conference on Supercomputing, 2003)
We describe a multi-perspective vision studio as a flexible high performance framework for solving complex image processing and machine vision problems on multi-view image sequences. The studio abstracts multi-view image data from image sequence acquisition facilities, stores and catalogs sequences in a high performance distributed database, allows customization of back-end processing services, and can serve custom client applications, thus helping make multi-view video sequence processing efficient and generic. To illustrate our approach, we describe two multi-perspective studio applications, and discuss performance and scalability results.
Keywords: database; distributed system; high-performance; IMAGE PROCESSING; multi-perspective; VISION; volumetric reconstruction

Identifying Relevant Information for Testing Technique Selection: An Instantiated Characterization Schema - Vegas,Sira; Juristo,Natalia; Basili, Victor R. (Springer, 2003)
The importance of properly selecting testing techniques is widely accepted in the software engineering community today. However, there are chiefly two reasons why the selections now made by software developers are difficult to evaluate as correct. First, there are several techniques with which the average developer is unfamiliar, often leaving testers with limited knowledge of all the techniques currently available. Second, the available information regarding the different testing techniques is primarily procedure (focused on how to use the technique), rather than pragmatic (focused on the effect and appropriateness of using the technique). The problem addressed in this book is aimed at improving software testing technique selection.Identifying Relevant Information for Testing Technique Selection: An Instantiated Characterization Schema will train its readers how to use the conceptual tool presented here in various ways. Developers will improve their testing technique selection process by systematically and objectively selecting the testing techniques for a software project. Developers will also build a repository containing their own experience with the application of various software testing techniques. Researchers will focus their research on the relevant aspects of testing technique when creating it, and when comparing different techniques.Identifying Relevant Information for Testing Technique Selection: An Instantiated Characterization Schema is designed to meet the needs of a professional audience in software engineering. This book is also suitable for graduate-level students in computer science and engineering.
Keywords: Business & Economics / Information Management; Computer software; Computer software - Testing; Computer software/ Testing; Computers / Information Technology; Computers / Internet / Application Development; Computers / Programming / General; Computers / Programming Languages / General; Computers / Software Development & Engineering / General; Computers / Software Development & Engineering / Quality Assurance & Testing; Technology & Engineering / Materials Science

Innovating the Interaction - Bederson, Benjamin B.; Plaisant, Catherine; Mushlin,R.; Snyder,A.; Li,J.; Heller,D.; Shneiderman, Ben; Hochheiser,H.; Fekete,J. D; Czenvinski,M. (The craft of information visualization: readings and reflectionsThe craft of information visualization: readings and reflections, 2003)

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)

Interactive color mosaic and dendrogram displays for signal/noise optimization in microarray data analysis - Seo,J.; Bakay,M.; Zhao,P.; Chen,Y.W.; Clarkson,P.; Shneiderman, Ben; Hoffman,E.P. (Multimedia and Expo, 2003. ICME'03. Proceedings. 2003 International Conference on, 2003)
Data analysis and visualization is strongly influenced by noise and noise filters. There are multiple sources of oisein microarray data analysis, but signal/noise ratios are rarely optimized, or even considered. Here, we report a noise analysis of a novel 13 million oligonucleotide dataset - 25 human U133A (~500,000 features) profiles of patient muscle biposies. We use our recently described interactive visualization tool, the Hierarchical Clustering Explorer (HCE) to systemically address the effect of different noise filters on resolution of arrays into orrectbiological groups (unsupervised clustering into three patient groups of known diagnosis). We varied probe set interpretation methods (MAS 5.0, RMA), resent callfilters, and clustering linkage methods, and investigated the results in HCE. HCE interactive features enabled us to quickly see the impact of these three variables. Dendrogram displays showed the clustering results systematically, and color mosaic displays provided a visual support for the results. We show that each of these three variables has a strong effect on unsupervised clustering. For this dataset, the strength of the biological variable was maximized, and noise minimized, using MAS 5.0, 10% present call filter, and Average Group Linkage. We propose a general method of using interactive tools to identify the optimal signal/noise balance or the optimal combination of these three variables to maximize the effect of the desired biological variable on data interpretation.

Interactive subsurface scattering for translucent meshes - Hao,Xuejun; Baby,Thomas; Varshney, Amitabh (Proceedings of the 2003 symposium on Interactive 3D graphics, 2003)
We propose a simple lighting model to incorporate subsurface scattering effects within the local illumination framework. Subsurface scattering is relatively local due to its exponential falloff and has little effect on the appearance of neighboring objects. These observations have motivated us to approximate the BSSRDF model and to model subsurface scattering effects by using only local illumination. Our model is able to capture the most important features of subsurface scattering: reflection and transmission due to multiple scattering.In our approach we build the neighborhood information as a preprocess and modify the traditional local illumination model into a run-time two-stage process. In the first stage we compute the reflection and transmission of light on the surface. The second stage involves bleeding the scattering effects from a vertex's neighborhood to produce the final result. We then show how to merge the run-time two-stage process into a run-time single-stage process using precomputed integral. The complexity of our run-time algorithm is O(N), where N is the number of vertices. Using this approach, we achieve interactive frame rates with about one to two orders of magnitude speedup compared with the state-of-the-art methods.
Keywords: BSSRDF; local illumination; reflection models; subsurface scattering

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)

Intradomain Overlays: Architecture and Applications - Kommareddy,Christopher; Guven,Tuna; Bhattacharjee, Bobby; La,Richard; Shayman,Mark (Technical Reports from UMIACS, UMIACS-TR-2003-70, 2003)
We introduce an architecture for ``Intradomain Overlays'', where a subset of routers within a domain is augmented with a dedicated host. These strategically placed hosts form an overlay network, and we describe a number of applications for such overlays. These applications include efficient network monitoring, policy- and load-based packet re-routing, and network resource accounting. In this paper, we elaborate on the network monitoring application and describe a distributed protocol for monitoring routers within an AS which has been augmented with a few overlay nodes. The routers and other infrastructure are unaware of the overlay nodes, and the monitoring of individual elements is conducted using plain SNMP. We describe techniques for efficiently synthesizing and transporting the monitored SNMP data, and present results using trace data collected from an AS with 400+ routers. Our results show that the overlay-based monitoring reduces overheads by 2--4 orders of magnitude, and thus enables much finer grained monitoring and traffic engineering than is otherwise possible. (UMIACS-TR-2003-70)
Keywords: Technical Report

Iterative and incremental developments. a brief history - Larman,C.; Basili, Victor R. (Computer, 2003)
Although many view iterative and incremental development as a modern practice, its application dates as far back as the mid-1950s. Prominent software-engineering thought leaders from each succeeding decade supported IID practices, and many large projects used them successfully. These practices may have differed in their details, but all had a common theme-to avoid a single-pass sequential, document-driven, gated-step approach.
Keywords: agile; and; developments; iterative; engineering; engineering; software; enhancement; software; incremental; methods; iterative; system; history; software

Lambertian reflectance and linear subspaces - Basri,R.; Jacobs, David W. (Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2003)
We prove that the set of all Lambertian reflectance functions (the mapping from surface normals to intensities) obtained with arbitrary distant light sources lies close to a 9D linear subspace. This implies that, in general, the set of images of a convex Lambertian object obtained under a wide variety of lighting conditions can be approximated accurately by a low-dimensional linear subspace, explaining prior empirical results. We also provide a simple analytic characterization of this linear space. We obtain these results by representing lighting using spherical harmonics and describing the effects of Lambertian materials as the analog of a convolution. These results allow us to construct algorithms for object recognition based on linear methods as well as algorithms that use convex optimization to enforce nonnegative lighting functions. We also show a simple way to enforce nonnegative lighting when the images of an object lie near a 4D linear space. We apply these algorithms to perform face recognition by finding the 3D model that best matches a 2D query image.
Keywords: 2D; 4D; 9D; analog; analytic; characterization; convex; convolution; distant; functions; harmonics; image; image; intensities; Lambertian; light; lighting; linear; methods; nonnegative; normals; object; optimization; programming; query; recognition; reflectance; reflectivity; set; sources; space; spherical; subspace; subspaces; surface

LifeLines: Using Visualization to Enhance Navigation and Analysis of Patient Records - Plaisant, Catherine; Mushlin,Richard; Snyder,Aaron; Li,Jia; Heller,Dan; Shneiderman, Ben (The Craft of Information VisualizationThe Craft of Information Visualization, 2003)

Logic foundry: rapid prototyping for FPGA-based DSP systems - Spivey,Gary; Bhattacharyya, Shuvra S.; Nakajima,Kazuo (EURASIP J. Appl. Signal Process., 2003)
We introduce the Logic Foundry, a system for the rapid creation and integration of FPGA-based digital signal processing systems. Recognizing that some of the greatest challenges in creating FPGA-based systems occur in the integration of the various components, we have proposed a system that targets the following four areas of integration: design flow integration, component integration, platform integration, and software integration. Using the Logic Foundry, a system can be easily specified, and then automatically constructed and integrated with system level software.
Keywords: CAD tools; Design methodology; DSP; FPGA; integration; rapid prototyping

Matching Software Measurements to Business Goals - Basili, Victor R. (Keynote Address at the 2003 Software Management Conference, San Jose, California, 2003)

Measuring the effects of internet path faults on reactive routing - Feamster, Nick; Andersen,David G.; Balakrishnan,Hari; Kaashoek,M. Frans (SIGMETRICS Perform. Eval. Rev., 2003)
Empirical evidence suggests that reactive routing systems improve resilience to Internet path failures. They detect and route around faulty paths based on measurements of path performance. This paper seeks to understand why and under what circumstances these techniques are effective.To do so, this paper correlates end-to-end active probing experiments, loss-triggered traceroutes of Internet paths, and BGP routing messages. These correlations shed light on three questions about Internet path failures: (1) Where do failures appear? (2) How long do they last? (3) How do they correlate with BGP routing instability?Data collected over 13 months from an Internet testbed of 31 topologically diverse hosts suggests that most path failures last less than fifteen minutes. Failures that appear in the network core correlate better with BGP instability than failures that appear close to end hosts. On average, most failures precede BGP messages by about four minutes, but there is often increased BGP traffic both before and after failures. Our findings suggest that reactive routing is most effective between hosts that have multiple connections to the Internet. The data set also suggests that passive observations of BGP routing messages could be used to predict about 20% of impending failures, allowing re-routing systems to react more quickly to failures.

Modelling pedestrian shapes for outlier detection: a neural net based approach - Nanda,H.; Benabdelkedar,C.; Davis, Larry S. (Intelligent Vehicles Symposium, 2003. Proceedings. IEEE, 2003)
In this paper we present an example-based approach to learn a given class of complex shapes, and recognize instances of that shape with outliers. The system consists of a two-layer custom-designed neural network. We apply this approach to the recognition of pedestrians carrying objects from a single camera. The system is able to capture and model an ample range of pedestrian shapes at varying poses and camera orientations, and achieves a 90% correct recognition rate.
Keywords: (artificial; complex; Computer; computing; custom; design; detection; engineering; intelligence); layer; learning; method; modelling; net; nets; neural; object; outlier; pedestrian; pedestrians; rate; recognition; recognition; SHAPE; shapes; traffic; two; vision

Navigation Patterns and Usability of Zoomable User Interfaces With and Without an Overview - Bederson, Benjamin B.; Plaisant, Catherine (The craft of information visualization: readings and reflections, 2003)

Navigation patterns & usability of zoomable user interfaces: with and without an overview - Hornbaek,Kasper; Bederson, Benjamin B.; Plaisant, Catherine (interactions, 2003)
The following abstracts are from recent issues and the forthcoming issue of ACM's Transactions of Computer Human Interaction (ToCHI). They are included here to alert interactions' readers to what research is being done in the field of Computer Human Interaction. The complete papers, when published, can be found in ACM's Digital Library at www.acm.org/pubs/contents/journals/tochi/

New eyes for robotics - Baker, P.; Ogale, A. S; Fermüller, Cornelia; Aloimonos, J. (2003 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2003. (IROS 2003). Proceedings, 2003)
This paper describes an imaging system that has been designed to facilitate robotic tasks of motion. The system consists of a number of cameras in a network arranged so that they sample different parts of the visual sphere. This geometric configuration has provable advantages compared to small field of view cameras for the estimation of the system's own motion and consequently the estimation of shape models from the individual cameras. The reason is that inherent ambiguities of confusion between translation and rotation disappear. Pairs of cameras may also be arranged in multiple stereo configurations which provide additional advantages for segmentation. Algorithms for the calibration of the system and the 3D motion estimation are provided.
Keywords: 3D motion estimation; Argus eye; array signal processing; Birds; Calibration; CAMERAS; Control systems; Eyes; geometric configuration; imaging; imaging system; Layout; Motion estimation; multiple stereo configurations; Robot kinematics; robot vision; Robot vision systems; ROBOTICS; Robotics and automation; SHAPE; shape models

Preserving Context with Zoomable User Interfaces - Hombsek,K.; Bederson, Benjamin B.; Plaisant, Catherine (The craft of information visualization: readings and reflectionsThe craft of information visualization: readings and reflections, 2003)

Recovery of a Digital Image Collection Through the SDSC/UMD/NARA Prototype Persistent Archive - Smorul,Mike; JaJa, Joseph F.; McCall,Fritz; Brown,Susan Fitch; Moore,Reagan; Marciano,Richard; Chen,Sheau-Yen; Lopez,Rick; Chadduck,Robert (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2003)
The San Diego Supercomputer Center (SDSC), the University of Maryland, and theNational Archives and Records Administration (NARA) are collaborating on building a pilot persistent archive using and extending data grid and digital library technologies. The current prototype consists of node servers at SDSC, University of Maryland, and NARA, connected through the Storage Request Broker (SRB) data grid middleware, and currently holds several terabytes of NARA selected collections. In particular, a historically important image collection that was on the verge of becoming inaccessible was fully restored and ingested into our pilot system. In this report, we describe the methodology behind our approach to fully restore this image collection and the process used to ingest it into the prototype persistent archive. (UMIACS-TR-2003-105)
Keywords: Technical Report

Replicated studies: building a body of knowledge about software reading techniques - Shull, F.; Carver, J.; Travassos,G.H.; Maldonado,J.C.; Conradi,R.; Basili, Victor R. (SERIES ON SOFTWARE ENGINEERING AND KNOWLEDGE ENGINEERING, 2003)

Resilient multicast using overlays - Banerjee,Suman; Lee,Seungjoon; Bhattacharjee, Bobby; Srinivasan, Aravind (SIGMETRICS Perform. Eval. Rev., 2003)
We introduce PRM (Probabilistic Resilient Multicast): a multicast data recovery scheme that improves data delivery ratios while maintaining low end-to-end latencies. PRM has both a proactive and a reactive component; in this paper we describe how PRM can be used to improve the performance of application-layer multicast protocols, especially when there are high packet losses and host failures. Further, using analytic techniques, we show that PRM can guarantee arbitrarily high data delivery ratios and low latency bounds. As a detailed case study, we show how PRM can be applied to the NICE application-layer multicast protocol. We present detailed simulations of the PRM-enhanced NICE protocol for 10,000 node Internet-like topologies. Simulations show that PRM achieves a high delivery ratio (> 97%) with a low latency bound (600 ms) for environments with high end-to-end network losses (1-5%) and high topology change rates (5 changes per second) while incurring very low overheads (< 5%).
Keywords: overlay multicast; randomized forwarding; Resilience

Secure agents - Bonatti,P. A; Kraus,S.; V.S. Subrahmanian (Annals of Mathematics and Artificial Intelligence, 2003)
With the rapid proliferation of software agents, there comes an increased need for agents to ensure that they do not provide data and/or services to unauthorized users. We first develop an abstract definition of what it means for an agent to preserve data/action security. Most often, this requires an agent to have knowledge that is impossible to acquire – hence, we then develop approximate security checks that take into account, the fact that an agent usually has incomplete/approximate beliefs about other agents. We develop two types of security checks – static ones that can be checked prior to deploying the agent, and dynamic ones that are executed at run time. We prove that a number of these problems are undecidable, but under certain conditions, they are decidable and (our definition of) security can be guaranteed. Finally, we propose a language within which the developer of an agent can specify her security needs, and present provably correct algorithms for static/dynamic security verification.

Seeing the World Through Image Libraries - North,C.; Shneiderman, Ben; Plaisant, Catherine; Kang,H.; Bederson, Benjamin B. (The craft of information visualization: readings and reflectionsThe craft of information visualization: readings and reflections, 2003)

The sequence and analysis of Trypanosoma brucei chromosome II - El‐Sayed, Najib M.; Ghedin,E.; Song,J.; MacLeod,A.; Bringaud,F.; Larkin,C.; Wanless,D.; Peterson,J.; Hou,L.; Taylor,S.; others (Nucleic acids research, 2003)

Special section on perceptual organization in computer vision - Jacobs, David W.; Lindenbaum,M.; August,J.; Zucker,SW; Ben-Shahar,O.; Zucker,SW; Tuytelaars,T.; Turina,A.; Van Gool,L.; Mahamud,S. (IEEE Computer Society, 2003)

Starting an intergenerational technology design team: a case study - Knudtzon,Kendra; Druin, Allison; Kaplan,Nancy; Summers,Kathryn; Chisik,Yoram; Kulkarni,Rahul; Moulthrop,Stuart; Weeks,Holly; Bederson, Benjamin B. (Proceedings of the 2003 conference on Interaction design and children, 2003)
This paper presents a case study of the first three months of a new intergenerational design team with children ages 10--13. It discusses the research and design methods used for working with children of this age group, the challenges and opportunities of starting a new team, and the lessons learned.
Keywords: children; cooperative inquiry; design methods; educational applications; intergenerational design teams; participatory design

Statistical physical model for foliage clutter in ultra-wideband synthetic aperture radar images - Banerjee,Amit; Chellapa, Rama (Journal of the Optical Society of America AThe Journal of the Optical Society of America A, 2003)
Analyzing foliage-penetrating (FOPEN) ultra-wideband synthetic aperture radar (SAR) images is a challenging problem owing to the noisy and impulsive nature of foliage clutter. Indeed, many target-detection algorithms for FOPEN SAR data are characterized by high false-alarm rates. In this work, a statistical–physical model for foliage clutter is proposed that explains the presence of outliers in the data and suggests the use of symmetric alpha-stable (SαS) distributions for accurate clutter modeling. Furthermore, with the use of general assumptions of the noise sources and propagation conditions, the proposed model relates the parameters of the SαS model to physical parameters such as the attenuation coefficient and foliage density.
Keywords: IMAGE PROCESSING; Remote sensing and sensors

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

Temporal probabilistic object bases - Biazzo,V.; Giugno,R.; Lukasiewicz,T.; V.S. Subrahmanian (Knowledge and Data Engineering, IEEE Transactions on, 2003)
There are numerous applications where we have to deal with temporal uncertainty associated with objects. The ability to automatically store and manipulate time, probabilities, and objects is important. We propose a data model and algebra for temporal probabilistic object bases (TPOBs), which allows us to specify the probability with which an event occurs at a given time point. In explicit TPOB-instances, the sets of time points along with their probability intervals are explicitly enumerated. In implicit TPOB-instances, sets of time points are expressed by constraints and their probability intervals by probability distribution functions. Thus, implicit object base instances are succinct representations of explicit ones; they allow for an efficient implementation of algebraic operations, while their explicit counterparts make defining algebraic operations easy. We extend the relational algebra to both explicit and implicit instances and prove that the operations on implicit instances correctly implement their counterpart on explicit instances.
Keywords: algebra; algebraic; bases; constraints; data; database; database; databases; distribution; explicit; functions; handling; implicit; instances; integrity; intervals; management; model; models; object; object-oriented; operations; probabilistic; probability; probability; relational; temporal; theory; Uncertainty; uncertainty

Thwarting Web Censorship with Untrusted Messenger Discovery - Feamster, Nick; Balazinska,Magdalena; Wang,Winston; Balakrishnan,Hari; Karger,David (Privacy Enhancing TechnologiesPrivacy Enhancing Technologies, 2003)
All existing anti-censorship systems for the Web rely on proxies to grant clients access to censored information. Therefore, they face the proxy discovery problem : how can clients discover the proxies without having the censor discover and block these proxies? To avoid widespread discovery and blocking, proxies must not be widely published and should be discovered in-band. In this paper, we present a proxy discovery mechanism called keyspace hopping that meets this goal. Similar in spirit to frequency hopping in wireless networks, keyspace hopping ensures that each client discovers only a small fraction of the total number of proxies. However, requiring clients to independently discover proxies from a large set makes it practically impossible to verify the trustworthiness of every proxy and creates the possibility of having untrusted proxies. To address this, we propose separating the proxy into two distinct components—the messenger , which the client discovers using keyspace hopping and which simply acts as a gateway to the Internet; and the portal , whose identity is widely-published and whose responsibility it is to interpret and serve the client’s requests for censored content. We show how this separation, as well as in-band proxy discovery, can be applied to a variety of anti-censorship systems.
Keywords: Computer science

Towards a logic for wide-area Internet routing - Feamster, Nick; Balakrishnan,Hari (SIGCOMM Comput. Commun. Rev., 2003)
Interdomain routing is a massive distributed computing task that propagates topological information for global reachability. Today's interdomain routing protocol, BGP4, is exceedingly complex because the wide variety of goals that it must meet---including fast convergence, failure resilience, scalability, policy expression, and global reachability---are accomplished by mechanisms that have complicated interactions and unintended side effects. The complexity of wide-area routing configuration and protocol dynamics requires mechanisms for expressing wide-area routing that adhere to a set of logical rules. We propose a set of rules, called the routing logic, which can be used to determine whether a routing protocol satisfies various properties. We demonstrate how this logic can aid in analyzing the behavior of BGP4 under various configurations. We also speculate on how the logic can be used to analyze existing configuration in real-world networks, synthesize network-wide router configuration from a high-level policy language, and assist protocol designers in reasoning about new routing protocols.

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

On the use of flow migration for handling short-term overloads - Kuo,Kuo-Tung; Phuvoravan,S.; Bhattacharjee, Bobby; Jun La,R.; Shayman,M.; Chang,Hyeong Soo (Global Telecommunications Conference, 2003. GLOBECOM '03. IEEE, 2003)
In this work, we investigate flow migration as a mechanism to sustain QoS to network users during short-term overloads in the context of an MPLS IP network. We experiment with three different control techniques: static long-term optimal mapping of flows to LSPs; on-line locally optimal mapping of flows to LSPs at flow set-up time; and dynamic flow migration in response to transient congestion. These techniques are applicable over different timescales, have different run-time overheads, and require different levels of monitoring and control software inside the network. We present results both from detailed simulations and a complete implementation using software IP routers. We use voice-over-IP as our test application, and show that if end-to-end quality is to be maintained during short unpredictable bursts of high load, then a fast-timescale control such as migration is required.
Keywords: computing; CONGESTION; congestion; CONTROL; control; dynamic; end-to-end; engineering; fast-timescale; flow; Internet; IP; label; long-term; mapping; migration; MPLS; multiprotocol; network; network; networks; of; optimal; overloads; protocol; QoS; QUALITY; quality; routers; routing; service; set-up; short-term; software; software; static; switching; Telecommunication; telephony; time; transient; voice-over-IP

Use of the SAND spatial browser for digital government applications - Samet, Hanan; Alborzi,Houman; Brabec,František; Esperança,Claudio; Hjaltason,Gísli R.; Morgan,Frank; Tanin,Egemen (Commun. ACM, 2003)
Numerous federal agencies produce official statistics made accessible to ordinary citizens for searching and data retrieval. This is frequently done via the Internet through a Web browser interface. If this data is presented in textual format, it can often be searched and retrieved by such attributes as topic, responsible agency, keywords, or press release. However, if the data is of spatial nature, for example, in the form of a map, then using text-based queries is often too cumbersome for the intended audience. We describe the use of the SAND Spatial Browser to provide more power to users of these databases by enabling them to define and explore the specific spatial region of interest graphically. The SAND Spatial Browser allows users to form either purely spatial or mixed spatial/nonspatial queries intuitively, which can present information to users that might have been missed if only a textual interface was available.
Keywords: GIS

User interface evaluation and empirically-based evolution of a prototype experience management tool - Seaman,C.B; Mendonca,M.G.; Basili, Victor R.; Kim,Y. M (Software Engineering, IEEE Transactions on, 2003)
Experience management refers to the capture, structuring, analysis, synthesis, and reuse of an organization's experience in the form of documents, plans, templates, processes, data, etc. The problem of managing experience effectively is not unique to software development, but the field of software engineering has had a high-level approach to this problem for some time. The Experience Factory is an organizational infrastructure whose goal is to produce, store, and reuse experiences gained in a software development organization. This paper describes The Q-Labs Experience Management System (Q-Labs EMS), which is based on the Experience Factory concept and was developed for use in a multinational software engineering consultancy. A critical aspect of the Q-Labs EMS project is its emphasis on empirical evaluation as a major driver of its development and evolution. The initial prototype requirements were grounded in the organizational needs and vision of Q-Labs, as were the goals and evaluation criteria later used to evaluate the prototype. However, the Q-Labs EMS architecture, data model, and user interface were designed to evolve, based on evolving user needs. This paper describes this approach, including the evaluation that was conducted of the initial prototype and its implications for the further development of systems to support software experience management.
Keywords: data; development; empirical; EMS; engineering; evaluation; experience; experience; Factory; interface; interfaces; knowledge; management; management; model; models; organization; performance; prototype; Q-Labs; re-engineering; reusability; reuse; software; system; systems; tool; user

VASCO: visualizing and animating spatial constructs and operations - Brabec,Frantivsek; Samet, Hanan; Yilmaz,Cemal (Proceedings of the nineteenth annual symposium on Computational geometry, 2003)
A video is used to demonstrate a set of spatial index JAVA applets that enable users on the worldwide web to experiment with a number of variants of the quadtree spatial data structure for different spatial data types, and, most importantly, enable them to see in an animated manner how a number of basic search operations are executed for them. The spatial data types are points, line segments, rectangles, and regions. The search operations are the window query (i.e., a spatial range query) and a nearest neighbor query that enables ranking spatial objects in the order of their distance from a given query object. The representations and algorithms are visualized and animated in a consistent manner using the same primitives and colors so that the differences between the effects of the representations can be easily understood. The video demonstrates the PR quadtree, PM1 quadtree, and R-tree. The applets can be found at: www.cs.umd.edu/~hjs/quadtree/.
Keywords: k-d trees; Nearest neighbor algorithms; quadtrees; R-trees; Visualization

The virtual microscope - Catalyurek,U.; Beynon,M. D; Chang,Chialin; Kurc, T.; Sussman, Alan; Saltz, J. (IEEE Transactions on Information Technology in Biomedicine, 2003)
We present the design and implementation of the virtual microscope, a software system employing a client/server architecture to provide a realistic emulation of a high power light microscope. The system provides a form of completely digital telepathology, allowing simultaneous access to archived digital slide images by multiple clients. The main problem the system targets is storing and processing the extremely large quantities of data required to represent a collection of slides. The virtual microscope client software runs on the end user's PC or workstation, while database software for storing, retrieving and processing the microscope image data runs on a parallel computer or on a set of workstations at one or more potentially remote sites. We have designed and implemented two versions of the data server software. One implementation is a customization of a database system framework that is optimized for a tightly coupled parallel machine with attached local disks. The second implementation is component-based, and has been designed to accommodate access to and processing of data in a distributed, heterogeneous environment. We also have developed caching client software, implemented in Java, to achieve good response time and portability across different computer platforms. The performance results presented show that the Virtual Microscope systems scales well, so that many clients can be adequately serviced by an appropriately configured data server.
Keywords: biomedical optical imaging; client software; client/server architecture; Computer architecture; Computer Graphics; computer platforms; Computer simulation; Concurrent computing; configured data server; data server software; database management systems; database software; Database systems; digital slide images; digital telepathology; diseases; emulation; Environment; Equipment Design; Equipment Failure Analysis; high power light microscope; Image databases; Image Enhancement; Image Interpretation, Computer-Assisted; Image retrieval; Information retrieval; Information Storage and Retrieval; java; local disks; microscope image data; Microscopy; multiple clients; optical microscopy; PACS; software; Software design; software system; Software systems; Systems Integration; Telepathology; User-Computer Interface; virtual microscope design; Virtual reality; Workstations

Visual Information Management for Network Configuration - Kumar,Harsha; Plaisant, Catherine; Teittinen,Marko; Shneiderman, Ben (The Craft of Information VisualizationThe Craft of Information Visualization, 2003)
Current network management systems rely heavily on forms in their user interfaces. The interfaces reflect the intricacies of the network hardware components but provide little support for guiding users through tasks. There is a scarcity of useful graphical visualizations and decision-support tools.

What makes a good answer? The role of context in question answering - Jimmy Lin; Quan,D.; Sinha,V.; Bakshi,K.; Huynh,D.; Katz,B.; Karger,D. R (Human-Computer Interaction, Interact '03, 2003)

What test oracle should I use for effective GUI testing? - Memon, Atif M.; Banerjee,I.; Nagarajan,A. (Automated Software Engineering, 2003. Proceedings. 18th IEEE International Conference on, 2003)
Test designers widely believe that the overall effectiveness and cost of software testing depends largely on the type and number of test cases executed on the software. In this paper we show that the test oracle used during testing also contributes significantly to test effectiveness and cost. A test oracle is a mechanism that determines whether software executed correctly for a test case. We define a test oracle to contain two essential parts: oracle information that represents expected output; and an oracle procedure that compares the oracle information with the actual output. By varying the level of detail of oracle information and changing the oracle procedure, a test designer can create different types of test oracles. We design 11 types of test oracles and empirically compare them on four software systems. We seed faults in software to create 100 faulty versions, execute 600 test cases on each version, for all 11 types of oracles. In all, we report results of 660,000 test runs on software. We show (1) the time and space requirements of the oracles, (2) that faults are detected early in the testing process when using detailed oracle information and complex oracle procedures, although at a higher cost per test case, and (3) that employing expensive oracles results in detecting a large number of faults using relatively smaller number of test cases.
Keywords: empirical studies; graphical user interface; Graphical user interfaces; GUI testing; oracle information; oracle procedure; oracle space requirement; oracle time requirements; program testing; software engineering; Software testing; test cost; test effectiveness; test oracle

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)

ALLI: An Information Integration System Based on Active Logic Framework - Barfourosh,A. A.; Nezhad,H. R.M; Anderson,M.; Perlis, Don (Proceedings of the Third International Conference on Management Information Systems, Greece, 2002)

Analysis of the NICE Application Layer Multicast Protocol - Banerjee,Suman; Bhattacharjee, Bobby (Technical Reports from UMIACS, UMIACS-TR-2002-60, 2002)
Application layer multicast protocols organize a set of hosts intoan overlay tree for data delivery. Each host on the overlay peers with a subset of other hosts. Since application layer multicast relies only on an underlying unicast architecture, multiple copies of the same packet can be carried by a single physical link or node on the overlay. The stress at a link or node is defined as the number of identical copies of a packet carried by that link or node. Stretch is another important metric in application layer multicast, which measures the relative increase in delay incurred by the overlay path between pairs of members with respect to the direct unicast path. In this paper we study the NICE application layer multicast protocol to quantify and study the tradeoff between these two important metrics --- stress and stretch in scalably building application layer multicast paths. Also UMIACS-TR-2002-60
Keywords: Technical Report

Are virtualized overlay networks too much of a good thing? - Keleher,P.; Bhattacharjee, Bobby; Silaghi,B. (Peer-to-Peer Systems, 2002)
The majority of recent high-profile work in peer-to-peer networks has approached the problem of location by abstracting over object lookup services. Namespace virtualization in the overlay layer provides load balance and provable bounds on latency at low costs.We contend that namespace virtualization comes at a significant cost for applications that naturally describe their data sets in a hierarchical manner. Opportunities for enhancing browsing, prefetching and efficient attribute-based searches are lost. A hierarchy exposes relationships between items near to each other in the topology; virtualization of the namespace discards this information even if present at client, higherlevel protocols. We advocate encoding application hierarchies directly into the structure of the overlay network, and revisit this argument through a newly proposed distributed directory service.

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)

On cache replacement policies for servicing mixed data intensive query workloads - Andrade,H.; Kurc, T.; Sussman, Alan; Borovikov,E.; Saltz, J. (Proceedings of the 2nd Workshop on Caching, Coherence, and Consistency, held in conjunction with the 16th ACM International Conference on Supercomputing, 2002)
When data analysis applications are employed in a multi-client environment, a data server must service multiple si- multaneous queries, each of which may employ complex user-defined data structures and operations on the data. It is then necessary to harness inter- and intra-query com- monalities and system resources to improve the performance of the data server. We have developed a framework and customizable middleware to enable reuse of intermediate and final results among queries, through an in-memory ac- tive semantic cache and user-defined transformation func- tions. Since resources such as processing power and mem- ory space are limited on the machine hosting the server, ef- fective scheduling of incoming queries and efficient cache replacement policies are challenging issues that must be ad- dressed. We have worked on the scheduling problem in ear- lier work, and in this paper we describe and evaluate several cache replacement policies. We present experimental eval- uation of the policies on a shared-memory parallel system using two applications from different application domains.

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.

A comparative study of application layer multicast protocols - Banerjee,S.; Bhattacharjee, Bobby (Network, 2002)
Due to the sparse deployment of IP multicast inthe Internet today, some researchers have proposed applica- tion layer multicast as a new approach to implement wide- area multicast services. In this approach multicast func- tionality is implemented at the end-hosts instead of network routers. Unlike network-layer multicast, application layer multicast requires no infrastructure support and can be eas- ily deployed in the Internet. In this paper, we describe a set of application layer multicast protocols that have been pro- posed in recent literature, classify them based on some prop- erties and present a comparison of performance and appli- cability of these schemes.

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 component architecture for FPGA-based, DSP system design - Spivey,G.; Bhattacharyya, Shuvra S.; Nakajima,K. (Application-Specific Systems, Architectures and Processors, 2002. Proceedings. The IEEE International Conference on, 2002)

COTS-based software development: Processes and open issues - Morisio,M; Seaman,C.B; Basili, Victor R.; Parra,A.T; Kraft,S.E; Condon,S.E (Journal of Systems and Software, 2002)
The work described in this paper is an investigation of the COTS-based software development within a particular NASA environment, with an emphasis on the processes used. Fifteen projects using a COTS-based approach were studied and their actual process was documented. This process is evaluated to identify essential differences in comparison to traditional software development. The main differences, and the activities for which projects require more guidance, are requirements definition and COTS selection, high level design, integration and testing. Starting from these empirical observations, a new process and set of guidelines for COTS-based development are developed and briefly presented.
Keywords: Commercial off-the-shelf; Component-based; COTS; empirical study; Software development process

Efficient Data Processing using Cross Layer Hints - Banerjee,Suman; Agrawala, Ashok K.; Kramer,Michael J (Technical Reports from UMIACS, UMIACS-TR-2002-59, 2002)
Conventional network stacks define a layered architecture, whereeach layer implements a set of services and exports a well-defined interface to be used by its immediate upper layer. A key design choice of the layered architecture has been to provide isolation between the functional modules of distinct layers. While such an architecture provides an useful abstraction for system development, the strict isolation of this layered architecture limits the flexibility of tailoring the behavior of the lower layers of the stack to the needs of the application. In this paper we define a new architecture, called X-Tags, which allows flexible interaction between layers for cooperative data processing without impacting the isolation property. In this architecture, applications use special tags to provide semantic hints for data processing to lower layers. We motivate the usefulness of this architecture by describing ts applicability to some emerging applications. UMIACS-TR-2002-59
Keywords: Technical Report

Efficient Manipulation of Large Datasets on Heterogeneous Storage Systems - Beynon,Michael D.; Sussman, Alan; Kurc,Tahsin; Catalyurek,Umit; Saltz,Joel (Parallel and Distributed Processing Symposium, International, 2002)
In this paper we are concerned with the efficient use of a collection of disk-based storage systems and computing platforms in a heterogeneous setting for retrieving and processing large scientific datasets. We demonstrate, in the context of a data-intensive visualization application, how heterogeneity affects performance and show a set of optimization techniques that can be used to improve performance in a component-based framework. In particular, we examine the application of parallelism via transparent copies of application components in the pipelined processing of data.
Keywords: component-based frameworks; data-intensive computing; load balancing

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)

Empirical findings in agile methods - Lindvall,M.; Basili, Victor R.; Boehm,B.; Costa,P.; Dangle,K.; Shull, F.; Tesoriero,R.; Williams,L.; Zelkowitz, Marvin V (Extreme Programming and Agile Methods—XP/Agile Universe 2002, 2002)
In recent years, the use of, interest in, and controversy about Agile methodologies have realized dramatic growth. Anecdotal evidence is rising regarding the effectiveness of agile methodologies in certain environments and for specified projects. However, collection and analysis of empirical evidence of this effectiveness and classification of appropriate environments for Agile projects has not been conducted. Researchers from four institutions organized an eWorkshop to synchronously and virtually discuss and gather experiences and knowledge from eighteen Agile experts spread across the globe. These experts characterized Agile Methods and communicated experiences using these methods on small to very large teams. They discussed the importance of staffing Agile teams with highly skilled developers. They shared common success factors and identified warning signs of problems in Agile projects. These and other findings and heuristics gathered through this valuable exchange can be useful to researchers and to practitioners as they establish an experience base for better decision making.

Executing Multiple Pipelined Data Analysis Operations in the Grid - Spencer,Matthew; Ferreira,Renato; Beynon,Michael; Kurc,Tahsin; Catalyurek,Umit; Sussman, Alan; Saltz,Joel (SC Conference, 2002)
Processing of data in many data analysis applications can be represented as an acyclic, coarse grain data flow, from data sources to the client. This paper is concerned with scheduling of multiple data analysis operations, each of which is represented as a pipelined chain of processing on data. We define the scheduling problem for effectively placing components onto Grid resources, and propose two scheduling algorithms. Experimental results are presented using a visualization application.

The Experience factory organization - Basili, Victor R.; Seaman,C. (IEEE Software, 2002)

Experience in implementing a learning software organization - Schneider,K.; von Hunnius,J.-P.; Basili, Victor R. (Software, IEEE, 2002)
In an effort to improve software development and acquisition processes and explicitly reuse knowledge from previous software projects, DaimlerChrysler created a software experience center (SEC). The authors report on challenges the company faced in creating the SEC
Keywords: ACQUISITION; center; software; centres; project; DaimlerChrysler; explicit; development; experience; improvement; improvement; automobile; industry; computer; knowledge; management; software; organization; previous; process; processes; software; projects; software; reuse; learning; software

Experimental Evaluation of the Unavailability Induced by a Group Membership Protocol - Joshi,Kaustubh; Michel Cukier; Sanders,William (Dependable Computing EDCC-4, 2002)
Group communication is an important paradigm for building highly available distributed systems. However, group membership operations often require the system to block message traffic, causing system services to become unavailable. This makes it important to quantify the unavailability induced by membership operations. This paper experimentally evaluates the blocking behavior of the group membership protocol of the Ensemble group communication system using a novel global-state-based fault injection technique. In doing so, we demonstrate how a layered distributed protocol such as the Ensemble group membership protocol can be modeled in terms of a state machine abstraction, and show how the resulting global state space can be used to specify fault triggers and define important measures on the system. Using this approach, we evaluate the cost associated with important states of the protocol under varying workload and group size. We also evaluate the sensitivity of the protocol to the occurrence of a second correlated crash failure during its operation.
Keywords: Computer science

An extraction-based verification methodology for MEMS - Baidya,B.; Gupta,S.K.; Mukherjee,T. (Microelectromechanical Systems, Journal of, 2002)
Micromachining techniques are being increasingly used to develop miniaturized sensor and actuator systems. These system designs tend to be captured as layout, requiring extraction of the equivalent microelectromechanical circuit as a necessary step for design verification. This paper presents an extraction methodology to (re-)construct a circuit schematic representation from the layout, enabling the designer to use microelectromechanical circuit simulators to verify the functional behavior of the layout. This methodology uses a canonical representation of the given layout on which feature-based and graph-based recognition algorithms are applied to generate the equivalent extracted schematic. Extraction can be performed to either the atomic level or the functional level representation of the reconstructed circuit. The choice of level in hierarchy is governed by the trade off between simulation time and simulation accuracy of the extracted circuit. The combination of the MEMS layout extraction and lumped-parameter circuit simulation provides MEMS designers with VLSI-like tools enabling faster design cycles, and improved design productivity
Keywords: atomic level; canonical representation; circuit schematic representation; circuit simulation; design cycles; design productivity; design verification; digital simulation; equivalent circuits; equivalent microelectromechanical circuit; extraction-based verification methodology; feature-based recognition algorithms; functional behavior; functional level; graph-based recognition algorithms; layout extraction; lumped parameter networks; lumped-parameter circuit simulation; MEMS; microelectromechanical circuit simulators; micromachining techniques; micromechanical devices; simulation accuracy; simulation time

Generating 3D Models of MEMS Devices by Process Emulation - Bellam,S.; Gupta, Satyandra K.; Priyadarshi,A. K. (Institute for Systems Research, University of Maryland, College Park, 2002)
MEMS designers often use numerical simulation for detecting errors in the mask layout. Numerical simulation involves generating 3D models of MEMS device from the mask layout and process description. The generated models can be meshed and simulated over different domains. This report describes an efficient algorithm that can generate 3D geometric models of MEMS devices. Specifically, the algorithm emulates the manufacturing of a single functional polysilicon layer MEMS devices using the MUMPSprocess.
Keywords: Next-Generation Product Realization Systems

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.

Getting real about speech: overdue or overhyped? - James,Frankie; Lai,Jennifer; Suhm,Bernhard; Balentine,Bruce; Makhoul,John; Nass,Clifford; Shneiderman, Ben (CHI '02 extended abstracts on Human factors in computing systems, 2002)
Speech has recently made headway towards becoming a more mainstream interface modality. For example, there is an increasing number of call center applications, especially in the airline and banking industries. However, speech still has many properties that cause its use to be problematic, such as its inappropriateness in both very quiet and very noisy environments, and the tendency of speech to increase cognitive load. Concerns about such problems are valid; however, they do not explain why the use of speech is so controversial in the HCI community. This panel would like to address the issues underlying the controversy around speech, by discussing the current state of the art, the reasons it is so difficult to build a good speech interface, and how HCI research can contribute to the development of speech interfaces.
Keywords: cognitive load; social responses; speech interfaces

High-level synthesis of DSP applications using adaptive negative cycle detection - Chandrachoodan,Nitin; Bhattacharyya, Shuvra S.; Liu,K. J.R (EURASIP J. Appl. Signal Process., 2002)
The problem of detecting negative weight cycles in a graph is examined in the context of the dynamic graph structures that arise in the process of high level synthesis (HLS). The concept of adaptive negative cycle detection is introduced, in which a graph changes over time and negative cycle detection needs to be done periodically, but not necessarily after every individual change. We present an algorithm for this problem, based on a novel extension of the well-known Bellman-Ford algorithm that allows us to adapt existing cycle information to the modified graph, and show by experiments that our algorithm significantly outperforms previous incremental approaches for dynamic graphs. In terms of applications, the adaptive technique leads to a very fast implementation of Lawlers algorithm for the computation of the maximum cycle mean (MCM) of a graph, especially for a certain form of sparse graph. Such sparseness often occurs in practical circuits and systems, as demonstrated, for example, by the ISCAS 89/93 benchmarks. The application of the adaptive technique to design-space exploration (synthesis) is also demonstrated by developing automated search techniques for scheduling iterative data-flow graphs.
Keywords: adaptive performance estimation; dynamic graphs; maximum cycle mean; negative cycle detection

Identification of non-autonomous non-LTR retrotransposons in the genome of Trypanosoma cruzi - Bringaud,Frédéric; García-Pérez,José Luis; Heras,Sara R.; Ghedin,Elodie; El‐Sayed, Najib M.; Andersson,Björn; Baltz,Théo; Lopez,Manuel C. (Molecular and Biochemical Parasitology, 2002)
As observed for most eukaryotic cells, trypanosomatids contains non-LTR retrotransposons randomly inserted in the nuclear genome. Autonomous retroelements which, code for their own transposition, have been characterized in Trypanosoma brucei (ingi) and Trypanosoma cruzi (L1Tc), whereas non-autonomous retroelements have only been characterized in T. brucei (RIME). Here, we have characterized in the genome of Trypanosoma cruzi four complete copies of a non-autonomous non-LTR retrotransposon, called NARTc. This 0.26 kb NARTc element has the characteristics of non-LTR retrotransposons: the presence a poly(dA) tail and of a short flanking duplicated motif. Analysis of the Genome Survey Sequence databases indicated that the Trypanosoma cruzi haploid genome contains about 140 NARTc copies and about twice as many L1Tc copies. Interestingly, the NARTc and L1Tc retroelements share, with the Trypanosoma brucei ingi and RIME retrotransposons, a common sequence (the first 45 bp with 91% identity), whereas the remaining sequences are very divergent. This suggests that these four trypanosome non-LTR retrotransposons were derived from the same common ancester and the sequence of their 5'-extremity may have a functional role. In addition, the genome of Leishmania major contains the same conserved motif present in the trypanosome retroelements, whicle no transposable elements have been detected so far in Leishmania sp.
Keywords: Ingi; L1Tc; Non-LTR retrotransposon; RIME; Trypanosoma brucei; Trypanosoma cruzi

Impediments to software engineering technology transfer - Zelkowitz, Marvin V; Wallace,D. R; Binkley,D. W (Journal of Systems and Software. Forthcoming, 2002)

Incremental unforgeable encryption - Buonanno,E.; Katz, Jonathan; Yung,M. (Fast Software Encryption, 2002)
The recent selection of the AES block cipher to replace DES has generated interest in developing new modes of operation to supplement the modes defined as part of the DES standard [1,16,23]. We initiate the study of modes of encryption which are both incremental and unforgeable, and point out a number of applications for modes meeting these requirements. We also propose three specific modes achieving these goals, and discuss the strengths and weaknesses of each.

Infranet: Circumventing web censorship and surveillance - Feamster, Nick; Balazinska,M.; Harfst,G.; Balakrishnan,H.; Karger,D. (Proceedings of the 11th USENIX Security Symposium, 2002)
An increasing number of countries and companies routinely block or monitor access to parts of the Internet. To counteract these measures, we propose Infranet, a system that enables clients to surreptitiously retrieve sensitive content via cooperating Web servers distributed across the global Internet. These Infranet servers provide clients access to censored sites while continuing to host normal uncensored content. Infranet uses a tunnel protocol that provides a covert communication channel between its clients and servers, modulated over standard HTTP transactions that resemble innocuous Web browsing. In the upstream direction, Infranet clients send covert messages to Infranet servers by associating meaning to the sequence of HTTP requests being made. In the downstream direction, Infranet servers return content by hiding censored data in uncensored images using steganographic techniques. We describe the design, a prototype implementation, security properties, and performance of Infranet. Our security analysis shows that Infranet can successfully circumvent several sophisticated censoring techniques.

Intermediate representations for design automation of multiprocessor DSP systems - Bambha,N.; Kianzad,V.; Khandelia,M.; Bhattacharyya, Shuvra S. (Design Automation for Embedded Systems, 2002)

Lessons learned from 25 years of process improvement: the rise and fall of the NASA software engineering laboratory - Basili, Victor R.; McGarry,Frank E.; Pajerski,Rose; Zelkowitz, Marvin V (Proceedings of the 24th International Conference on Software Engineering, 2002)
For 25 years the NASA/GSFC Software Engineering Laboratory (SEL) has been a major resource in software process improvement activities. But due to a changing climate at NASA, agency reorganization, and budget cuts, the SEL has lost much of its impact. In this paper we describe the history of the SEL and give some lessons learned on what we did right, what we did wrong, and what others can learn from our experiences. We briefly describe the research that was conducted by the SEL, describe how we evolved our understanding of software process improvement, and provide a set of lessons learned and hypotheses that should enable future groups to learn from and improve on our quarter century of experiences.

A light-weight process for capturing and evolving defect reduction experience - Basili, Victor R.; Lindvall,M.; Shull, F. (Engineering of Complex Computer Systems, 2002. Proceedings. Eighth IEEE International Conference on, 2002)
Selecting technologies for developing software is a crucial activity in software projects. Defect reduction is an example of an area in which software developers have to decide what technologies to use. CeBASE is a NSF funded project that has the role of improving software development by providing decision support on the selection of techniques and tools. The decision support is based on empirical data organized in experience bases and refined into high-level models. Empirical data is collected through various activities, for example through eWorkshops in which experts discuss important issues, and formalized using the lightweight knowledge dust to knowledge pearl process.
Keywords: bases; experience; CeBASE; NSF; defect; development; software; experience; software; funded; knowledge; software; management; lightweight; management; software; project; decision; projects; software; reduction; reusability; software; reuse; software; support; eWorkshops; experience; tools; tools; knowledge

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.

Navigation patterns and usability of zoomable user interfaces with and without an overview - Hornbaek,K.; Bederson, Benjamin B.; Plaisant, Catherine (ACM Transactions on Computer-Human Interaction (TOCHI), 2002)

A new, expressed multigene family containing a hot spot for insertion of retroelements is associated with polymorphic subtelomeric regions of Trypanosoma brucei - Bringaud,F.; Biteau,N.; Melville,S. E.; Hez,S.; El‐Sayed, Najib M.; Leech,V.; Berriman,M.; Hall,N.; Donelson,J. E; Baltz,T. (Eukaryotic cell, 2002)

A non-intrusive Kalman filter-based tracker for pursuit eye movement - Abd-Almageed, Wael; Fadali,M. S; Bebis,G. (American Control Conference, 2002. Proceedings of the 2002, 2002)
In this paper, we introduce a new non-intrusive approach to estimating the eye position during pursuit motion of the eye. We introduce a new characterization for the pursuit eye movement. Our characterization is based on the decomposition of the pursuit eye motion into a deterministic component and random component. We use a discrete Kalman filter to estimate the random component and calculate the deterministic component. We add the two components to obtain an estimate of the eye position. Simulation results are provided to illustrate the eye position estimation.
Keywords: Application software; characterization; Computer vision; Current measurement; deterministic component; Electric variables measurement; eye position estimation; eye tracking; gaze tracking; Human computer interaction; Kalman filter; Kalman filters; Lenses; Motion estimation; Optical reflection; pursuit eye movement; pursuit motion; random component; Skin; tracking

An operational process for goal-driven definition of measures - Briand,L.C.; Morasca,S.; Basili, Victor R. (Software Engineering, IEEE Transactions on, 2002)
We propose an approach (GOM/MEDEA) for defining measures of product attributes in software engineering. The approach is driven by the experimental goals of measurement, expressed via the GQM paradigm, and a set of empirical hypotheses. To make the empirical hypotheses quantitatively verifiable, GQM/MEDEA supports the definition of theoretically valid measures for the attributes of interest based on their expected mathematical properties. The empirical hypotheses are subject to experimental verification. This approach integrates several research contributions from the literature into a consistent, practical, and rigorous approach.
Keywords: attributes; definition; development; empirical; engineering; expected; experimental; goal-driven; GQM; GQM/MEDEA; hypotheses; management; mathematical; measure; measurement; metrics; operational; paradigm; process; Product; properties; quality; software; verification

Optimizing execution of component-based applications using group instances - Beynon,Michael D.; Kurc,Tahsin; Sussman, Alan; Saltz,Joel (Future Generation Computer Systems, 2002)
Recent research on programming models for developing applications on the Grid has proposed component-based models as a viable approach, in which an application is composed of multiple interacting computational objects. We have been developing a framework, called filter-stream programming, for building data-intensive applications that query, analyze and manipulate very large datasets in a distributed environment. In this model, the processing structure of an application is represented as a set of processing units, referred to as filters. In this paper, we develop the problem of scheduling instances of a filter group. A filter group is a set of filters collectively performing a computation for an application. In particular, we seek the answer to the following question: should a new instance be created, or an existing one reused? We experimentally investigate the effects on performance of instantiating multiple filter groups under varying application characteristics.
Keywords: DataCutter; Grid; Wide-area network

Ordered and quantum treemaps: Making effective use of 2D space to display hierarchies - Bederson, Benjamin B.; Shneiderman, Ben; Wattenberg,Martin (ACM Transactions on Graphics (TOG), 2002)
Treemaps, a space-filling method for visualizing large hierarchical data sets, are receiving increasing attention. Several algorithms have been previously proposed to create more useful displays by controlling the aspect ratios of the rectangles that make up a treemap. While these algorithms do improve visibility of small items in a single layout, they introduce instability over time in the display of dynamically changing data, fail to preserve order of the underlying data, and create layouts that are difficult to visually search. In addition, continuous treemap algorithms are not suitable for displaying fixed-sized objects within them, such as images.This paper introduces a new "strip" treemap algorithm which addresses these shortcomings, and analyzes other "pivot" algorithms we recently developed showing the trade-offs between them. These ordered treemap algorithms ensure that items near each other in the given order will be near each other in the treemap layout. Using experimental evidence from Monte Carlo trials and from actual stock market data, we show that, compared to other layout algorithms, ordered treemaps are more stable, while maintaining relatively favorable aspect ratios of the constituent rectangles. A user study with 20 participants clarifies the human performance benefits of the new algorithms. Finally, we present quantum treemap algorithms, which modify the layout of the continuous treemap algorithms to generate rectangles that are integral multiples of an input object size. The quantum treemap algorithm has been applied to PhotoMesa, an application that supports browsing of large numbers of images.
Keywords: hierarchies; Human-computer interaction; image browsers; Information Visualization; jazz; ordered treemaps; treemaps; TREES; zoomable user interfaces (ZUIs).

OZONE: A zoomable interface for navigating ontology information - Suh,B.; Bederson, Benjamin B. (Proceedings of the Working Conference on Advanced Visual Interfaces, 2002)

P5 : a protocol for scalable anonymous communication - Sherwood,R.; Bhattacharjee, Bobby; Srinivasan, Aravind (2002 IEEE Symposium on Security and Privacy, 2002. Proceedings, 2002)
We present a protocol for anonymous communication over the Internet. Our protocol, called P5 (peer-to-peer personal privacy protocol) provides sender-, receiver-, and sender-receiver anonymity. P5 is designed to be implemented over current Internet protocols, and does not require any special infrastructure support. A novel feature of P5 is that it allows individual participants to trade-off degree of anonymity for communication efficiency, and hence can be used to scalably implement large anonymous groups. We present a description of P5, an analysis of its anonymity and communication efficiency, and evaluate its performance using detailed packet-level simulations.
Keywords: Broadcasting; communication efficiency; Computer science; cryptography; data privacy; Educational institutions; Internet; large anonymous groups; P5 protocol; packet-level simulations; Particle measurements; Peer to peer computing; peer-to-peer personal privacy protocol; privacy; Protocols; receiver anonymity; scalable anonymous communication; security of data; sender anonymity; sender-receiver anonymity; Size measurement; telecommunication security

Packet loss recovery for streaming video - Feamster, Nick; Balakrishnan,H. (12th International Packet Video Workshop, 2002)
While there is an increasing demand for streaming video applica-tions on the Internet, various network characteristics make the de- ployment of these applications more challenging than traditional TCP-based applications like email and the Web. Packet loss can be detrimental to compressed video with interdependent frames be- cause errors potentially propagate across many frames. While la- tency requirements do not permit retransmission of all lost data, we leverage the characteristics of MPEG-4 to selectively retrans- mit only the most important data in the bitstream. When latency constraints do not permit retransmission, we propose a mechanism for recovering this data using postprocessing techniques at the re- ceiver. We quantify the effects of packet loss on the quality of MPEG-4 video, develop an analytical model to explain these ef- fects, present a system to adaptively deliver MPEG-4 video in the face of packet loss and variable Internet conditions, and evaluate the effectiveness of the system under various network conditions.

Perturbation technique for LLG dynamics in uniformly magnetized bodies subject to RF fields - Bertotti,G.; Mayergoyz, Issak D; Serpico,C. (Magnetics, IEEE Transactions on, 2002)
The problem of magnetization dynamics of a uniformly magnetized uniaxial particle or film, under elliptically polarized applied field, is considered. In the special case of circularly polarized applied field and particles (films) with a symmetry axis, pure time-harmonic magnetization modes exist that can be computed analytically. Deviations from these highly symmetric conditions are treated as perturbation of the symmetric case. The perturbation technique leads to the exactly solvable system of linear differential equations for the perturbations which enables one to compute higher order magnetization harmonic. The analytical solutions are obtained and then compared with numerical results.
Keywords: analytical; anisotropy; anisotropy; applied; bodies; circularly; component; constant-in-time; constant; damping; demagnetisation; demagnetizing; differential; dynamics; effective; elliptically; equation; equations; exactly; factors; field; film; films; Frequency; gyromagnetic; harmonic; higher; Landau-Lifshitz-Gilbert; large; linear; magnetic; magnetisation; magnetization; magnetization; magnetized; modes; MOTION; order; partial; particle; particles; perturbation; polarized; radio; ratio; RF; saturation; solution; solvable; system; technique; techniques; thin; time-harmonic; uniaxial; uniformly

Processing large-scale multi-dimensional data in parallel and distributed environments - Beynon,Michael; Chang,Chialin; Catalyurek,Umit; Kurc,Tahsin; Sussman, Alan; Andrade,Henrique; Ferreira,Renato; Saltz,Joel (Parallel Computing, 2002)
Analysis of data is an important step in understanding and solving a scientific problem. Analysis involves extracting the data of interest from all the available raw data in a dataset and processing it into a data product. However, in many areas of science and engineering, a scientist's ability to analyze information is increasingly becoming hindered by dataset sizes. The vast amount of data in scientific datasets makes it a difficult task to efficiently access the data of interest, and manage potentially heterogeneous system resources to process the data. Subsetting and aggregation are common operations executed in a wide range of data-intensive applications. We argue that common runtime and programming support can be developed for applications that query and manipulate large datasets. This paper presents a compendium of frameworks and methods we have developed to support efficient execution of subsetting and aggregation operations in applications that query and manipulate large, multi-dimensional datasets in parallel and distributed computing environments.
Keywords: Data-intensive applications; Distributed computing; Multi-dimensional datasets; PARALLEL PROCESSING; Runtime systems

Query routing in the TerraDir distributed directory - Silaghi,B.; Bhattacharjee, Bobby; Keleher,P. (Proceedings of the SPIE ITCOM, 2002)
We present the design and evaluation of the query-routing protocol of the TerraDir distributed directory.TerraDir is a wide-area distributed directory designed for hierarchical namespaces, and provides a lookup service for mapping keys to objects. We introduce distributed lookup and caching algorithms that leverage the underlying data hierarchy. Our algorithms provide efficient lookups while avoiding the load imbalances often associated with hierarchical systems. The TerraDir load balancing scheme also incorporates a node replication algorithm that provides configurable failure resilience with provably low overheads.

Remote access to large spatial databases - Tanin,Egemen; Brabec,František; Samet, Hanan (Proceedings of the 10th ACM international symposium on Advances in geographic information systems, 2002)
Enterprises in the public and private sectors have been making their large spatial data archives available over the Internet. However, interactive work with such large volumes of online spatial data is a challenging task. We propose two efficient approaches to remote access to large spatial data. First, we introduce a client-server architecture where the work is distributed between the server and the individual clients for spatial query evaluation, data visualization, and data management. We enable the minimization of the requirements for system resources on the client side while maximizing system responsiveness as well as the number of connections one server can handle concurrently. Second, for prolonged periods of access to large online data, we introduce APPOINT (an Approach for Peer-to-Peer Offloading the INTernet). This is a centralized peer-to-peer approach that helps Internet users transfer large volumes of online data efficiently. In APPOINT, active clients of the client-server architecture act on the server's behalf and communicate with each other to decrease network latency, improve service bandwidth, and resolve server congestions.
Keywords: client/server; GIS; Internet; peer-to-peer

Remote thin-client access to spatial database systems - Samet, Hanan; Brabec,František (Proceedings of the 2002 annual national conference on Digital government research, 2002)
Numerous federal agencies produce official statistics that are made accessible to ordinary citizens for searching and data retrieval. This is often done via the Internet through a web browser interface. If this data is presented in textual format, it can often be searched and retrieved by such attributes as topic, responsible agency, keywords, or press release. However, if the data is of spatial nature, e.g., in the form of a map, then using text-based queries is often too cumbersome for the intended audience. We propose to use the capabilities of the SAND Spatial Browser to provide more power to users of these databases. Using the SAND Spatial Browser allows users to define the spatial region of interest with greater specificity, instead of forcing them to retrieve data just for a particular location or a region with a predefined boundary. They can also make use of ranking which is the ability to retrieve data in the order of distance from other instances of the data or aggregates of data that are user-defined. Work is distributed between the SAND server and the individual clients for query evaluation, data visualization and data management. This enables the minimization of the necessary requirements for system resources on the client side while maximizing the number of connections one server can handle concurrently. Concrete experience with interfacing the SAND system with FedStats data is also discussed.