Rover: scalable location-aware computing - Banerjee,S.; Agarwal,S.; Kamel,K.; Kochut, A.; Kommareddy,C.; Nadeem,T.; Thakkar,P.; Trinh,Bao; Youssef,A.; Youssef, M.; Larsen,R.L.; Udaya Shankar,A.; et al. (Computer, 2002)
All the components necessary for realizing location-aware computing are available in the marketplace today. What has hindered the widespread deployment of location-based systems is the lack of an integration architecture that scales with user populations. The authors have completed the initial implementation of Rover, a system designed to achieve this sort of integration and to automatically tailor information and services to a mobile user's location. Their studies have validated Rover's underlying software architecture, which achieves system scalability through high-resolution, application-specific resource scheduling at the servers and network. The authors believe that this technology will greatly enhance the user experience in many places, including museums, amusement and theme parks, shopping malls, game fields, offices, and business centers. They designed the system specifically to scale to large user populations and expect its benefits to increase with them.
Keywords: amusement; application-specific; architecture; automation; business; business; computing; data; entertainment; handheld; humanities; integration; LAN; location-aware; malls; mobile; museums; office; parks; processing; resource; Rover; scalability; scalable; scheduling; shopping; software; system; theme; units; user; wireless

Scalable application layer multicast - Banerjee,Suman; Bhattacharjee, Bobby; Kommareddy,Christopher (SIGCOMM Comput. Commun. Rev., 2002)
We describe a new scalable application-layer multicast protocol, specifically designed for low-bandwidth, data streaming applications with large receiver sets. Our scheme is based upon a hierarchical clustering of the application-layer multicast peers and can support a number of different data delivery trees with desirable properties.We present extensive simulations of both our protocol and the Narada application-layer multicast protocol over Internet-like topologies. Our results show that for groups of size 32 or more, our protocol has lower link stress (by about 25%), improved or similar end-to-end latencies and similar failure recovery properties. More importantly, it is able to achieve these results by using orders of magnitude lower control traffic.Finally, we present results from our wide-area testbed in which we experimented with 32-100 member groups distributed over 8 different sites. In our experiments, average group members established and maintained low-latency paths and incurred a maximum packet loss rate of less than 1% as members randomly joined and left the multicast group. The average control overhead during our experiments was less than 1 Kbps for groups of size 100.
Keywords: application layer multicast; hierarchy; overlay networks; peer-to-peer systems; scalability

Scalable peer finding on the Internet - Banerjee,S.; Kommareddy,C.; Bhattacharjee, Bobby (Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE, 2002)
We consider the problem of finding nearby application peers over the Internet. We define a new peer-finding scheme (called Tiers) that scales to large application peer groups. Tiers creates a hierarchy of the peers, which allows an efficient and scalable solution to this problem. The scheme can be implemented entirely in the application-layer and does not require the deployment of either any additional measurement services, or well-known reference landmarks in the network. We present detailed evaluation of Tiers and compare it to one previously proposed scheme called Beaconing. Through analysis and detailed simulations on 10,000 node Internet-like topologies we show that Tiers achieves comparable or better performance with a significant reduction in control overheads for groups of size 32 or more.
Keywords: application; application-layer; Beaconing; CONTROL; finding; Internet-like; Internet; measurement; network; overhead; peer; peer-finding; peers; protocol; protocols; reduction; scalable; scheme; services; simulations; solution; Tiers; topologies; topology

Scalable secure group communication over IP multicast - Banerjee,S.; Bhattacharjee, Bobby (Selected Areas in Communications, IEEE Journal on, 2002)
We introduce and analyze a scalable rekeying scheme for implementing secure group communications Internet protocol multicast. We show that our scheme incurs constant processing, message, and storage overhead for a rekey operation when a single member joins or leaves the group, and logarithmic overhead for bulk simultaneous changes to the group membership. These bounds hold even when group dynamics are not known a priori. Our rekeying algorithm requires a particular clustering of the members of the secure multicast group. We describe a protocol to achieve such clustering and show that it is feasible to efficiently cluster members over realistic Internet-like topologies. We evaluate the overhead of our own rekeying scheme and also of previously published schemes via simulation over an Internet topology map containing over 280 000 routers. Through analysis and detailed simulations, we show that this rekeying scheme performs better than previous schemes for a single change to group membership. Further, for bulk group changes, our algorithm outperforms all previously known schemes by several orders of magnitude in terms of actual bandwidth usage, processing costs, and storage requirements.
Keywords: access; algorithm; authentication; Bandwidth; communication; CONTROL; costs; cryptography; dynamics; group; group; Internet; Internet-like; Internet; IP; logarithmic; map; membership; message; Multicast; multicast; network; overhead; PROCESSING; protocol; protocols; rekeying; requirements; routers; routing; scalable; secure; security; server; simulation; storage; Telecommunication; topologies; Topology; topology; transport; usage

SpaceTree: Design evolution of a node link tree browser - Plaisant, Catherine; Grosjean,J.; Bederson, Benjamin B. (Proc. InfoVis, 2002)

SpaceTree: supporting exploration in large node link tree, design evolution and empirical evaluation - Plaisant, Catherine; Grosjean,J.; Bederson, Benjamin B. (Information Visualization, 2002. INFOVIS 2002. IEEE Symposium on, 2002)
We present a novel tree browser that builds on the conventional node link tree diagrams. It adds dynamic rescaling of branches of the tree to best fit the available screen space, optimized camera movement, and the use of preview icons summarizing the topology of the branches that cannot be expanded. In addition, it includes integrated search and filter functions. This paper reflects on the evolution of the design and highlights the principles that emerged from it. A controlled experiment showed benefits for navigation to already previously visited nodes and estimation of overall tree topology.
Keywords: browser; camera; data; design; diagrams; dynamic; evolution; experiment; exploration; filter; functions; graphical; icons; integrated; interfaces; large; link; movement; node; novel; optimized; rescaling; search; SpaceTree; structures; topology; tree; user; visualisation; visualization

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

Topology inference from BGP routing dynamics - Andersen,David G.; Feamster, Nick; Bauer,Steve; Balakrishnan,Hari (Proceedings of the 2nd ACM SIGCOMM Workshop on Internet measurment, 2002)
This paper describes a method of inferring logical relationships between network prefixes within an Autonomous System (AS) using only passive monitoring of BGP messages. By clustering these prefixes based upon similarities between their update times, we create a hierarchy linking the prefixes within the larger AS. We can frequently identify groups of prefixes routed to the same ISP Point of Presence (POP), despite the lack of identifying information in the BGP messages. Similarly, we observe disparate prefixes under common organizational control, or with long shared network paths. In addition to discovering interesting network characteristics, our passive method facilitates topology discovery by potentially reducing the number of active probes required in traditional traceroute-based Internet mapping mechanisms.

Trypanosoma cruzi: RNA structure and post-transcriptional control of tubulin gene expression - Bartholomeu,Daniella C.; Silva,Rosiane A.; Galvão,Lucia M. C.; El‐Sayed, Najib M.; Donelson,John E.; Teixeira,Santuza M.R. (Experimental Parasitology, 2002)
Changes in tubulin expression are among the biochemical and morphological adaptations that occur during the life cycle of Trypanosomatids. To investigate the mechanism responsible for the differential accumulation of tubulin mRNAs in Trypanosoma cruzi, we determine the sequences of [alpha]- and [beta]-tubulin transcripts and analyzed their expression during the life cycle of the parasite. Two [beta]-tubulin mRNAs of 1.9 and 2.3 kb were found to differ mainly by an additional 369 nucleotides at the end of the 3' untranslated region (UTR). Although their transcription rates are similar in epimastigotes and amastigotes, [alpha]- and [beta]-tubulin transcripts are 3- to 6-fold more abundant in epimastigotes than in trypomastigotes and amastigotes. Accordingly, the half-lives of [alpha]- and [beta]-tubulin mRNAs are significantly higher in epimastigotes than in amastigotes. Transient transfection experiments indicated that positive regulatory elements occur in the 3' UTR plus downstream intergenic region of the [alpha]-tubulin gene and that both positive and negative elements occur in the equivalent regions of the [beta]-tubulin gene.Index Descriptions and Abbreviations: Kinetoplastida; Trypanosoma cruzi; tubulin; gene regulation; PCR, polymerase chain reaction; UTR, untranslated region; IR, intergenic region; SL, spliced leader; BAC, bacterial artificial chromosome.

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

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

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

Visual space-time geometry - A tool for perception and the imagination - Fermüller, Cornelia; Baker, P.; Aloimonos, J. (Proceedings of the IEEE, 2002)
Although the fundamental ideas underlying research efforts in the field of computer vision have not radically changed in the past two decades, there has been a transformation in the way work in this field is conducted. This is primarily due to the emergence of a number of tools, of both a practical and a theoretical nature. One such tool, celebrated throughout the nineties, is the geometry of visual space-time. It is known under a variety of headings, such as multiple view geometry, structure from motion, and model building. It is a mathematical theory relating multiple views (images) of a scene taken at different viewpoints to three-dimensional models of the (possibly dynamic) scene. This mathematical theory gave rise to algorithms that take as input images (or video) and provide as output a model of the scene. Such algorithms are one of the biggest successes of the field and they have many applications in other disciplines, such as graphics (image-based rendering, motion capture) and robotics (navigation). One of the difficulties, however is that the current tools cannot yet be fully automated, and they do not provide very accurate results. More research is required for automation and high precision. During the past few years we have investigated a number of basic questions underlying the structure from motion problem. Our investigations resulted in a small number of principles that characterize the problem. These principles, which give rise to automatic procedures and point to new avenues for studying the next level of the structure from motion problem, are the subject of this paper.
Keywords: 3-D motion estimation; Buildings; Computer vision; Geometry; Graphics; Image sequences; Layout; Mathematical model; mathematical theory; model building; Motion estimation; multiple view geometry; multiple views; Navigation; optical flow; optical illusions; patch correspondence; Rendering (computer graphics); Robotics and automation; Solid modeling; structure from motion; three-dimensional models; visual space-time

Web question answering: is more always better? - Dumais,Susan; Banko,Michele; Brill,Eric; Jimmy Lin; Ng,Andrew (Proceedings of the 25th annual international ACM SIGIR conference on Research and development in information retrieval, 2002)
This paper describes a question answering system that is designed to capitalize on the tremendous amount of data that is now available online. Most question answering systems use a wide variety of linguistic resources. We focus instead on the redundancy available in large corpora as an important resource. We use this redundancy to simplify the query rewrites that we need to use, and to support answer mining from returned snippets. Our system performs quite well given the simplicity of the techniques being utilized. Experimental results show that question answering accuracy can be greatly improved by analyzing more and more matching passages. Simple passage ranking and n-gram extraction techniques work well in our system making it efficient to use with many backend retrieval engines.

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

Zoomable user interfaces as a medium for slide show presentations - Good,L.; Bederson, Benjamin B. (Information Visualization, 2002)

Adaptive negative cycle detection in dynamic graphs - Chandrachoodan,N.; Bhattacharyya, Shuvra S.; Liu,K. J.R (Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on, 2001)

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

Automatically Tracking and Analyzing the Behavior of Live Insect Colonies - Balch, Tucker; Zia Khan; Veloso, Manuela (AGENTS '01 Proceedings of the Fifth International Conference on Autonomous Agents, 2001)
We introduce the study of {\it live} social insect colonies as a relevant and exciting domain for the development and application of multi-agent systems modeling tools. Social insects provide a rich source of {\it traceable} social behavior for testing multi-agent tracking, prediction and modeling algorithms. An additional benefit of this research is the potential for contributions to experimental biology --- the principled techniques developed for analyzing artificial multi-agent systems can be applied to advance the state of knowledge of insect behavior. We contribute a novel machine vision system that addresses the challenge of tracking hundreds of small animals simultaneously. Fast color-based tracking is combined with movement-based tracking to locate ants in a real-time video stream. We also introduce new methods for analyzing the spatial activity of ant colonies. The system was validated in experiments with laboratory colonies of {\it Camponotus festinatus} and several example analyses of the colonies' spatial behavior are provided.

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

COTS-based systems top 10 list - Basili, Victor R.; Boehm,B. (Computer, 2001)
Presents a COTS-based system (CBS) software defect-reduction list as hypotheses, rather than results, that also serve as software challenges for enhancing our empirical understanding of CBSs. The hypotheses are: (1) more than 99% of all executing computer instructions come from COTS products (each instruction passed a market test for value); (2) more than half the features in large COTS software products go unused; (3) the average COTS software product undergoes a new release every 8-9 months, with active vendor support for only its latest three releases; (4) CBS development and post-deployment efforts can scale as high as the square of the number of independently developed COTS products targeted for integration; (5) CBS post-deployment costs exceed CBS development costs; (6) although glue-code development usually accounts for less than half the total CBS software development effort, the effort per line of glue code averages about three times the effort per line of developed applications code; (7) non-development costs, such as licensing fees, are significant, and projects must plan for and optimize them; (8) CBS assessment and tailoring efforts vary significantly by COTS product class (operating system, database management system, user interface, device driver, etc.); (9) personnel capability and experience remain the dominant factors influencing CBS development productivity; and (10) CBS is currently a high-risk activity, with effort and schedule overruns exceeding non-CBS software overruns, yet many systems have used COTS successfully for cost reduction and early delivery
Keywords: activity; hypotheses; independently; capability; personnel; challenges; software; code; COTS-based; defect; delivery; glue; developed; development; development; high-risk; effort; products; effort; software; efforts; unused; experience; post-deployment; features; software; instructions; costs; development; integration; schedule; management; software; off-the; overruns; software; packages; software; productivity; early; products; personnel; quality; reduction; software; releases; system; shelf; support; commercial; systems; active; systems; computer; vendor

The Design of TerraDir - Bhattacharjee, Bobby; Keleher,Pete; Silaghi,Bujor (Technical Reports from UMIACS, UMIACS-TR-2001-4299, 2001)
We present the design and initial evaluation of TerraDir: an approach forimplementing customizable, distributed, peer-to-peer directories over which a broad range of wide-area resource discovery applications can be implemented. TerraDir's structure is two-tiered, consisting of a base protocol for providing arbitrary application-layer connectivity, and dynamic view materializations that efficiently realize different user-specified views of application-layer resources. TerraDir is specifically designed for data that can be arranged in a rooted hierarchy, and provides very efficient and robust lookups over such data while still being able to allow efficient searching. (Also referenced as UMIACS-TR-2001-4299)
Keywords: Technical Report

Designing an Interactive Message Board as a Technology Probe for Family Communication - Browne,Hilary; Bederson, Benjamin B.; Plaisant, Catherine; Druin, Allison (Technical Reports of the Computer Science Department, 2001)
In this paper, we describe the design issues and technical implementation of aninteractive Family Message Board. The Family Message Board enables members of a distributed family to communicate with one another both synchronously and asynchronously via simple, pen-based, digital notes. Each household running thi$ Java-based software can view, create, and manipulate notes in a zoomable space. The Family Message Board will be used as a technology probe to help us unders$ the communication needs of distributed families, and to help us design new devi$ to meet those needs.
Keywords: Technical Report

Distributed processing of very large datasets with DataCutter - Beynon,Michael D.; Kurc,Tahsin; Catalyurek,Umit; Chang,Chialin; Sussman, Alan; Saltz,Joel (Parallel Computing, 2001)
We describe a framework, called DataCutter, that is designed to provide support for subsetting and processing of datasets in a distributed and heterogeneous environment. We illustrate the use of DataCutter with several data-intensive applications from diverse fields, and present experimental results.
Keywords: Component architectures; Data analysis; Distributed computing; Multi-dimensional datasets; Runtime systems

Editorial: Open source and empirical software engineering - Basili, Victor R. (Empirical Software Engineering, 2001)

Efficient Model Checking Via Buchi Tableau Automata⋆ - Bhat,G. S; Cleaveland, Rance; Groce,A. (Computer aided verification: 13th International conference, CAV 2001, Paris, France, July 18-22, 2001: proceedings, 2001)

Efficient perspective-accurate silhouette computation and applications - Pop, Mihai; Duncan,Christian; Barequet,Gill; Goodrich,Michael; Huang,Wenjing; Kumar,Subodh (Proceedings of the seventeenth annual symposium on Computational geometry, 2001)
Silhouettes are perceptually and geometrically salient features of geo metric models. Hence a number of graphics and visualization applications need to find them to aid further processing. The efficient computation of silhouettes, especially in the context of perspective projection, is known to be difficult. This paper presents a novel efficient and practical algorithm to compute silhouettes from a sequence of viewpoints under perspective projection. Parallel projection is a special case of this algorithm. Our approach is based on a point-plane duality in three dimensions, which allows an efficient computation of the changes in the silhouette of a polygonal model between consecutive frames. In addition, we present several applications of our technique to problems from computer graphics and medical visualization. We also provide experimental data that show the efficiency of our approach. million vertices on an SGI Onyx workstation.
Keywords: rendering; silhouette; simplification

An efficient system for multi-perspective imaging and volumetric shape analysis - Borovikov,E.; Sussman, Alan; Davis, Larry S. (Proceedings of the 2001 Workshop on Parallel and Distributed Computing in Imaging Processing, Video Processing, and Multimedia, 2001)

An experience management system for a software engineering research organization - Basili, Victor R.; Costa,P.; Lindvall,M.; Mendonca,M.; Seaman,C.; Tesoriero,R.; Zelkowitz, Marvin V (Software Engineering Workshop, 2001. Proceedings. 26th Annual NASA Goddard, 2001)
Most businesses rely on the fact that their employees possess relevant knowledge and that they can apply it to the task at hand. The problem is that this knowledge is not owned by the organization. It is owned and controlled by its employees. Maintaining an appropriate level of knowledge in the organization is a very important issue. It is, however, not an easy task for most organizations, and it is particularly problematic for software organizations, which are human- and knowledge-intensive. Knowledge management is a relatively new area that has attempted to address these problems. This paper introduces an approach called the "knowledge dust-to-pearls" approach. This approach addresses some of the issues with knowledge management by providing low-barrier mechanisms to "jump start" the experience base. This approach allows the experience base to become more useful more quickly than traditional approaches. This paper describes the approach and gives an example of its use at the Fraunhofer Center for Experimental Software Engineering, Maryland, USA
Keywords: and; approach; knowledge; base; experience; Center; control; knowledge; data; development; dust-to-pearls; engineering; Engineering; business; engineering; software; experimental; for; Fraunhofer; houses; knowledge; employee; knowledge; experience; level; maintenance; knowledge; management; management; knowledge; management; software; mechanisms; software; organization; software; organizational; organizations; administrative; organizations; knowledge; organizations; low-barrier; ownership; knowledge-intensive; processing; personnel; research; research; software; system; human-intensive

Experimental Analysis of Algorithms for Bilateral-Contract Clearing Mechanisms Arising in Deregulated Power Industry - Barrett,Chris; Cook,Doug; Hicks,Gregory; Faber,Vance; Marathe,Achla; Marathe,Madhav; Srinivasan, Aravind; Sussmann,Yoram; Thornquist,Heidi (Algorithm EngineeringAlgorithm Engineering, 2001)
We consider the bilateral contract satisfaction problem arising from electrical power networks due to the proposed deregulation of the electric utility industry in the USA. Given a network and a (multi)set of pairs of vertices (contracts) with associated demands, the goal is to find the maximum number of simultaneously satisfiable contracts. We study how four different algorithms perform in fairly realistic settings; we use an approximate electrical power network from Colorado. Our experiments show that three heuristics outperform a theoretically better algorithm. We also test the algorithms on four types of scenarios that are likely to occur in a deregulated marketplace. Our results show that the networks that are adequate in a regulated marketplace might be inadequate for satisfying all the bilateral contracts in a deregulated industry.

Eyes from Eyes - Baker,Patrick; Pless,Robert; Fermüller, Cornelia; Aloimonos, J. (3D Structure from Images — SMILE 20003D Structure from Images — SMILE 2000, 2001)
We describe a family of new imaging systems, called Argus eyes, that consist of common video cameras arranged in some network. The system we built consists of six cameras arranged so that they sample different parts of the visual sphere. This system has the capability of very accurately estimating its own 3D motion and consequently estimating shape models from the individual videos. The reason is that inherent ambiguities of confusion between translation and rotation disappear in this case. We provide an algorithm and several experiments using real outdoor or indoor images demonstrating the superiority of the new sensor with regard to 3D motion estimation.

Finding close friends on the Internet - Kommareddy,C.; Shankar,N.; Bhattacharjee, Bobby (Network Protocols, 2001. Ninth International Conference on, 2001)
We consider the problem of finding nearby application-peers (close friends) over the Internet. We focus on unicast-only solutions and introduce a new scheme -Beaconing-for finding peers that are near. Our scheme uses distance measurement points (called beacons) and can be implemented entirely in the application-layer without investing in large infrastructure changes. We present an extensive evaluation of Beaconing and compare it to existing schemes including Expanding Ring searches and Triangulation. Our experiments show that 3-8 beacons are sufficient to provide efficient peer-location service on 10 000 node Internet-like topologies. Further, our results are 2-5 times more accurate than existing techniques. We also present results from an implementation of Beaconing over a non-trivial wide-area testbed. In our experiments, Beaconing is able to efficiently (< 3 K Bytes and < 50 packets on average), quickly (< 1 second on average), and accurately (< 20 ms error on average) find nearby peers on the Internet.
Keywords: application-layer; application-peers; Beaconing; beacons; close; distance; Expanding; friends; Internet-like; Internet; IP; measurement; nearby; network; peer-location; points; protocols; Ring; searches; service; solutions; testbed; topologies; topology; transport; Triangulation; unicast-only; wide-area

Handling uncertainty with active logic - Bhatia,M.; Chi,P.; Chong,W.; Josyula,D. P; Okamoto,Y.; Perlis, Don; Purang,K. (In Proceedings, AAAI Fall Symposium on Uncertainty in Computation, 2001)

Hybrid global/local search strategies for dynamic voltage scaling in embedded multiprocessors - Bambha,N. K; Bhattacharyya, Shuvra S.; Teich,J.; Zitzler,E. (Hardware/Software Codesign, 2001. CODES 2001. Proceedings of the Ninth International Symposium on, 2001)

Implementing the Experience Factory concepts as a set of Experience Bases - Basili, Victor R.; Lindvall,M.; Costa,P. (Proc. 13th Int’l Conf. Software Eng. and Knowledge Eng, 2001)
This talk takes the Experience Factory concept, which was originally developed as organizational support for softwaredevelopment and generalizes it to organizational support for any aspect of a business, e.g., business practices. The Experience Factory supports the evolution of processes and other forms of knowledge, based upon experiences within the organization, and related knowledge gathered from outside the organization. It then discusses how you might design an appropriate experience base for the particular set of organizational needs determined to be of importance. Specific examples are given in developing experience bases for specific organizations and it discusses the Experience Management System (EMS) currently being evolved and how it has been applied.

Integrated Microelectromechanical System (MEMS) Inertial Measurement Unit (IMIMU) - Fedder,Gary K.; Blanton,Shawn; Carley,L. R.; Gupta, Satyandra K.; Koester,David (CARNEGIE-MELLON UNIVERSITY, 2001)
Processes, designs and design tools are developed to enable the monolithic integration of arrays of inertial microsensors with electronics. Accelerometers and gyroscopes, fabricated in a single CMOS process, are functional and demonstrate a single chip IMU. Two integrated post CMOS micro-machining processes are demonstrated. Thin-film microstructures are defined from the metal-dielectric stack of a conventional process. In the second process, a back-side silicon etch, followed by front-side DRIE produces bulk silicon microstructures. Accelerometer and gyroscope designs are developed with accompanying low noise electronic circuitry. Noise performance was limited to 1/f circuit noise. The chip output sensibility is set by the interface circuit design. A thermally stabilized accelerometer and circuit design is demonstrated using embedded polysilicon resistors as temperature sensors and heaters in a closed loop. Nested gyroscope topologies are demonstrated with a lateral MEMS accelerometer used as a coriolis acceleration sensor. Modeling and simulation tools that simultaneously consider the electromechanical transducer and the electronic circuit to predict system performance are developed. Electrical, electromechanical and mechanical parasitics required to enable predictive lumped parameter simulation are identified and can be extracted, enabling a designer to confidently estimate design performance prior to fabrication. Generic physics-based fault models for surface-micromachined actuators and sensors are developed that enable effective testing, diagnosis and design for manufacturability.
Keywords: *ELECTROMECHANICAL DEVICES; *GYROSCOPES; *INERTIAL MEASUREMENT UNITS; *INERTIAL NAVIGATION; *MICROELECTROMECHANICAL SYSTEMS; ACCELEROMETERS; BULK MATERIALS; CHIPS(ELECTRONICS); CIRCUITS; CLOSED LOOP SYSTEMS; CORIOLIS EFFECT; Detectors; DIELECTRICS; ELECTRICAL AND ELECTRONIC EQUIPMENT; EMBEDDING; METALS; MICROSENSORS.; MICROSTRUCTURE; MONOLITHIC STRUCTURES(ELECTRONICS); NAVIGATION AND GUIDANCE; PARASITES; PE63739E; PERFORMANCE(ENGINEERING); POLYSILICONS; RESISTORS; SILICON; TEMPERATURE SENSITIVE ELEMENTS; THERMAL STABILITY; THIN FILMS; tools; Topology; WUAFRLE1170030

On the interactions between layered quality adaptation and congestion control for streaming video - Feamster, Nick; Bansal,D.; Balakrishnan,H. (11th International Packet Video Workshop, 2001)
This paper uses analysis and experiments to study the impact of var-ious congestion control algorithms and receiver buffering strategies on the performance of streaming media delivery. While traditional congestion avoidance schemes such as TCP’s additive-increase/- multiplicativedecrease (AIMD) achieve high utilization, they also cause large oscillations in transmission rates that degrade the smooth- ness and perceptual quality of the video stream. We focus on un- derstanding the interactions of a family of congestion control al- gorithms that generalize AIMD, with buffer-based quality adapta- tion algorithms for hierarchically-encoded and simulcast video. Our work builds on and extends the results of Rejaie et al. [19]; we find that the combination of a non-AIMD algorithm that has smaller os- cillations than AIMD and a suitable receiver buffer allocation and management strategy provides a good combination of low playout delay and TCP-friendly congestion control. The paper describes these mechanisms and the results of experiments conducted using a prototype video server for MPEG-4 video, showing that our ap- proach can improve the interactivity and adaptivity of Internet video.

Interpretation of Compound Nominals Using WordNet - Barrett,Leslie; Davis,Anthony; Dorr, Bonnie J (Computational Linguistics and Intelligent Text ProcessingComputational Linguistics and Intelligent Text Processing, 2001)
We describe an approach to interpreting noun-noun compounds within a question answering system. The system’s lexicon, based on WordNet, provides the basis for heuristics that group noun-noun compounds with seman- tically similar words. The semantic relationship between the nouns in a com- pound is determined by the choice of heuristic for the compound. We discuss procedures for selecting one heuristic in cases where several can apply to a compound, the effects of lexical ambiguity, and some initial results of our methods.

Judging whether multiple silhouettes can come from the same object - Jacobs, David W.; Belhumeur,P.; Jermyn,I. (Visual Form 2001, 2001)
We consider the problem of recognizing an object from its silhouette. We focus on the case in which the camera translates, and rotates about a known axis parallel to the image, such as when a mobile robot explores an environment. In this case we present an algorithm for determining whether a new silhouette could come from the same object that produced two previously seen silhouettes. In a basic case, when cross-sections of each silhouette are single line segments, we can check for consistency between three silhouettes using linear programming. This provides the basis for methods that handle more complex cases. We show many experiments that demonstrate the performance of these methods when there is noise, some deviation from the assumptions of the algorithms, and partial occlusion. Previous work has addressed the problem of precisely reconstructing an object using many silhouettes taken under controlled conditions. Our work shows that recognition can be performed without complete reconstruction, so that a small number of images can be used, with viewpoints that are only partly constrained.

Lambertian reflectance and linear subspaces - Basri,R.; Jacobs, David W. (Computer Vision, 2001. ICCV 2001. Proceedings. Eighth IEEE International Conference on, 2001)
We prove that the set of all reflectance functions (the mapping from surface normals to intensities) produced by Lambertian objects under distant, isotropic lighting lies close to a 9D linear subspace. This implies that the images of a convex Lambertian object obtained under a wide variety of lighting conditions can be approximated accurately with 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 non-negative lighting functions
Keywords: functions; spherical; harmonics; convex; Lambertian; lighting; object; object; convex; objects; convex; optimization; isotropic; programming; object; recognition; recognition; reflectance

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

Multiprocessor clustering for embedded systems - Kianzad,V.; Bhattacharyya, Shuvra S. (Euro-Par 2001 Parallel Processing, 2001)

Optimal collective dichotomous choice under partial order constraints - Ben-Yashar,Ruth; Khuller, Samir; Kraus,Sarit (Mathematical Social Sciences, 2001)
This paper generalizes optimal collective dichotomous choices by including constraints which limit combinations of acceptance and rejection decisions for m projects under consideration. Two types of constraints are examined. The first type occurs when acceptance of some projects requires acceptance of others. This type reduces the choice problem to the tractable (solvable in polynomial time) problem of finding a maximum weight closed subset of a directed acyclic graph. The second type occurs when some projects must be accepted when certain others are rejected. We show that this type renders the choice problem to be NP-complete by reduction from the problem of Vertex Cover. Applicability of the generalization to information filtering is discussed.
Keywords: constraints; Information filtering; Optimal collective dichotomous choice

Parameterized dataflow modeling for DSP systems - Bhattacharya,B.; Bhattacharyya, Shuvra S. (Signal Processing, IEEE Transactions on, 2001)

Performance optimization for data intensive grid applications - Beynon,M. D; Sussman, Alan; Catalyurek,U.; Kurc, T.; Saltz, J. (Active Middleware Services, 2001. Third Annual International Workshop on, 2001)

Projective alignment with regions - Basri,R.; Jacobs, David W. (Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2001)
We have previously proposed (Basri and Jacobs, 1999, and Jacobs and Basri, 1999) an approach to recognition that uses regions to determine the pose of objects while allowing for partial occlusion of the regions. Regions introduce an attractive alternative to existing global and local approaches, since, unlike global features, they can handle occlusion and segmentation errors, and unlike local features they are not as sensitive to sensor errors, and they are easier to match. The region-based approach also uses image information directly, without the construction of intermediate representations, such as algebraic descriptions, which may be difficult to reliably compute. We further analyze properties of the method for planar objects undergoing projective transformations. In particular, we prove that three visible regions are sufficient to determine the transformation uniquely and that for a large class of objects, two regions are insufficient for this purpose. However, we show that when several regions are available, the pose of the object can generally be recovered even when some or all regions are significantly occluded. Our analysis is based on investigating the flow patterns of points under projective transformations in the presence of fixed points
Keywords: algebra; object; alignment; projective; approach; segmentation; errors; image; fixed; objects; pose; occlusion; planar; patterns; partial; points; flow; recognition; recovery; projective; segmentation; matrix; transformations; region-based

A prototype experience management system for a software consulting organization - Mendonça Neto,M. G.; Seaman,C.; Basili, Victor R.; Kim,Y. M (Thirteenth International Conference on Software Engineering and Knowledge Engineering, 2001)
The Experience Management System (EMS) is aimed atsupporting the capture and reuse of software-related experience, based on the Experience Factory concept. It is being developed for use in a multinational software engineering consultancy, Q-Labs. Currently, a prototype EMS exists and has been evaluated. This paper focuses on the EMS architecture, underlying data model, implementation, and user interface.

Rotation, scale, and translation resilient public watermarking for images using a log-polar fourier transform - Bloom,Jeffrey A.; Cox,Ingemar J.; Miller,Matthew L.; M. Wu; Lin,Ching-Yung; Lui,Yui Man (2001)
A method for detecting a watermark signal in digital image data. The detecting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; comparing the extracted signal to a target watermark signal; and declaring the presence or absence of the target watermark signal in the image data based on the comparison. Also provided is a method for inserting a watermark signal in digital image data to obtain a watermarked image. The inserting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; modifying the extracted signal such that it is similar to a target watermark; performing a one-to-many mapping of the modified signal back to...

Rotation, scale, and translation resilient watermarking for images - Lin,C.-Y.; Wu,M.; Bloom,J.A.; Cox,I.J.; Miller,M.L.; Lui,Y.M. (Image Processing, IEEE Transactions on, 2001)
Many electronic watermarks for still images and video content are sensitive to geometric distortions. For example, simple rotation, scaling, and/or translation (RST) of an image can prevent blind detection of a public watermark. In this paper, we propose a watermarking algorithm that is robust to RST distortions. The watermark is embedded into a one-dimensional (1-D) signal obtained by taking the Fourier transform of the image, resampling the Fourier magnitudes into log-polar coordinates, and then summing a function of those magnitudes along the log-radius axis. Rotation of the image results in a cyclical shift of the extracted signal. Scaling of the image results in amplification of the extracted signal, and translation of the image has no effect on the extracted signal. We can therefore compensate for rotation with a simple search, and compensate for scaling by using the correlation coefficient as the detection measure. False positive results on a database of 10 000 images are reported. Robustness results on a database of 2000 images are described. It is shown that the watermark is robust to rotation, scale, and translation. In addition, we describe tests examining the watermarks resistance to cropping and JPEG compression
Keywords: axis; one-dimensional; coding; security; coefficient; cropping; cyclical; compression; RST; coordinates; log-radius; data; detection; correlation; distortions; blind; distortions; images; log-polar; encapsulation; image; Fourier; images; translation; magnitudes; Fourier; measure; geometric; of; protection; data; resilient; shift; detection; signal; public; transform; JPEG; transforms; copy; watermark; resampling; rotation; scale; search; still; watermarking; video; Fourier

Software Defect Reduction Top 10 List - Boehm,Barry; Basili, Victor R. (Computer, 2001)
Software's complexity and accelerated development schedules make avoiding defects difficult. These 10 techniques can help reduce the flaws in your code.

A spherical eye from multiple cameras (makes better models of the world) - Baker, P.; Fermüller, Cornelia; Aloimonos, J.; Pless, R. (Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2001. CVPR 2001, 2001)
The paper describes an imaging system that has been designed specifically for the purpose of recovering egomotion and structure from video. The system consists of six 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. We provide algorithms for the calibration of the system and 3D motion estimation. The calibration is based on a new geometric constraint that relates the images of lines parallel in space to the rotation between the cameras. The 3D motion estimation uses a constraint relating structure directly to image gradients.
Keywords: 3D motion estimation; Calibration; camera network; CAMERAS; Computer vision; egomotion recovery; geometric configuration; geometric constraint; image gradients; image sampling; imaging system; Laboratories; Layout; Motion estimation; multiple cameras; Pixel; Robot vision systems; SHAPE; shape models; Space technology; spherical eye; system calibration; video; video cameras; video signal processing; visual sphere sampling

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

Towards the ultimate motion capture technology - Stuart, B.; Baker, P.; Aloimonos, J. (Deformable avatars: IFIP TC5/WG5. 10 DEFORM'2000 Workshop, November 29-30, 2000, Geneva, Switzerland and AVATARS'2000 Workshop, November 30-December 1, 2000, Lausanne, Switzerland, 2001)

A trend analysis of exploitations - Browne,H. K; Arbaugh, William A.; McHugh,J.; Fithen,W. L (2001 IEEE Symposium on Security and Privacy, 2001. S&P 2001. Proceedings, 2001)
We have conducted an empirical study of a number of computer security exploits and determined that the rates at which incidents involving the exploit are reported to CERT can be modeled using a common mathematical framework. Data associated with three significant exploits involving vulnerabilities in phf, imap, and bind can all be modeled using the formula C=I+S×√M where C is the cumulative count of reported incidents, M is the time since the start of the exploit cycle, and I and S are the regression coefficients determined by analysis of the incident report data. Further analysis of two additional exploits involving vulnerabilities in mountd and statd confirm the model. We believe that the models will aid in predicting the severity of subsequent vulnerability exploitations, based on the rate of early incident reports
Keywords: Computer science; computer security exploits; Data analysis; data mining; Educational institutions; exploitations; Performance analysis; Predictive models; Regression analysis; Risk management; security of data; software engineering; system intrusions; System software; trend analysis; vulnerabilities; vulnerability exploitation

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

VEHICLE SPEED INFORMATION DISPLAYS FOR PUBLIC WEBSITES: A STUDY OF USER PREFERENCES - Plaisant, Catherine; Bhamidipati,P.; Tarnoff,P. (ITS 2001: Conference Proceedings, 2001)

Active source location and beamforming - Duraiswami, Ramani; Zotkin,Dmitry N; Borovikov,Eugene A.; Davis, Larry S. (The Journal of the Acoustical Society of America, 2000)

An API for Runtime Code Patching - Buck, Bryan; Hollingsworth, Jeffrey K (International Journal of High Performance Computing Applications, 2000)
The authors present a postcompiler program manipulation tool called Dyninst, which provides a C++ class library for program instrumentation. Using this library, it is possible to instrument and modify application programs during execution. A unique feature of this library is that it permits machine-independent binary instrumentation programs to be written. The authors describe the interface that a tool sees when using this library. They also discuss three simple tools built using this interface: a utility to count the number of times a function is called, a program to capture the output of an already running program to a file, and an implementation of conditional breakpoints. For the conditional breakpoint example, the authors show that by using their interface compared with gdb, they are able to execute a program with conditional breakpoints up to 900 times faster.

Approximating low-congestion routing and column-restricted packing problems - Baveja,Alok; Srinivasan, Aravind (Information Processing Letters, 2000)
We contribute to a body of research asserting that the fractional and integral optima of column-sparse integer programs are “nearby”. This yields improved approximation algorithms for some generalizations of the knapsack problem, with applications to low-congestion routing in networks, file replication in distributed databases, and other packing problems.
Keywords: algorithms; Approximation algorithms; integer programming; Packing; Routing

Approximation Algorithms for Disjoint Paths and Related Routing and Packing Problems - Baveja,Alok; Srinivasan, Aravind (Mathematics of Operations ResearchMathematics of Operations Research, 2000)
Given a network and a set of connection requests on it, we consider the maximum edge-disjoint paths and related generalizations and routing problems that arise in assigning paths for these requests. We present improved approximation algorithms and/or integrality gaps for all problems considered; the central theme of this work is the underlying multicommodity flow relaxation. Applications of these techniques to approximating families of packing integer programs are also presented.
Keywords: Approximation algorithms; Disjoint paths; integer programming; Linear programming; multicommodity flow; Packing; randomized algorithms; rounding; Routing; unsplittable flow

Comparative Evaluation of a Natural Language Dialog Based System and a Menu-Driven System for Information Access: A Case Study - Chai,J.; Jimmy Lin; Zadrozny,W.; Ye,Y.; Budzikowska,M.; Horvath,V.; Kambhatla,N.; Wolf,C. (In Proceedings of the International Conference on Multimedia Information Retrieval (RIAO 2000), 2000)
This paper describes the evaluation of a natural language dialog based navigation system (HappyAssistant) thathelps users access e-commerce sites to find relevant information about products and services. The prototype system leverages technologies in natural language processing and human computer interaction to create a faster and more intuitive way of interacting with websites, especially for the less experienced users. The result of a comparative study shows that users prefer the natural language enabled navigation two to one over the menu driven navigation. In addition, the study confirmed the efficiency of using natural language dialog in terms of the number of clicks and the amount of time required to obtain the relevant information. In the case study, comparing to the menu driven system, the average number of clicks used in the natural language system was reduced by 63.2% and the average time was reduced by 33.3%.

Convexity in Perceptual Completion - Liu,Z.; Jacobs, David W.; Basri,R. (KLUWER INTERNATIONAL SERIES IN ENGINEERING AND COMPUTER SCIENCE, 2000)

DataCutter: Middleware for filtering very large scientific datasets on archival storage systems - Beynon, M.; Ferreira,R.; Kurc, T.; Sussman, Alan; Saltz, J. (NASA conference publication, 2000)

Design and use of linear models for image motion analysis - Fleet,D. J; Black,M. J; Yacoob,Yaser; Jepson,A. D (International Journal of Computer Vision, 2000)

Design of a Framework for Data-Intensive Wide-Area Applications - Beynon,Michael D.; Kurc,Tahsin; Sussman, Alan; Saltz,Joel (Heterogeneous Computing Workshop, 2000)
Applications that use collections of very large, distributed datasets have become an increasingly important part of science and engineering. With high performance wide-area networks become more pervasive, there is interest in making collective use of distributed computational and data resources. Recent work has converged to the notion of the Grid, which attempts to uniformly present a heterogeneous collection of distributed resources. Current Grid research covers many areas from low-level infrastructure issues to high-level application concerns. However, providing support for efficient exploration and processing of very large scientific datasets stored in distributed archival storage systems remains a challenging research issue.We have initiated an effort that focuses on developing efficient data-intensive applications in a Grid environment. In this paper, we present a framework, called filter-stream programming that represents the processing units of a data-intensive application as a set of filters, which are designed to be efficient in their use of memory and scratch space. We describe a prototype infrastructure that supports execution of applications using the proposed framework. We present the implementation of two applications using the filter-stream programming framework, and discuss experimental results demonstrating the effects of heterogeneous resources on application performance.
Keywords: application decomposition; data analysis and exploration; Data-intensive applications

Designing StoryRooms: interactive storytelling spaces for children - Alborzi,H.; Druin, Allison; Montemayor,J.; Platner,M.; Porteous,J.; Sherman,L.; Boltman,A.; Taxén,G.; Best,J.; Hammer,J.; others (Proceedings of the 3rd conference on Designing interactive systems: processes, practices, methods, and techniques, 2000)

Designing storytelling technologies to encouraging collaboration between young children - Benford,S.; Bederson, Benjamin B.; \AAkesson,K. P; Bayon,V.; Druin, Allison; Hansson,P.; Hourcade,J. P; Ingram,R.; Neale,H.; O'Malley,C.; others (Proceedings of the SIGCHI conference on Human factors in computing systems, 2000)

Detecting independent motion: The statistics of temporal continuity - Pless, R.; Brodsky, T.; Aloimonos, J. (Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2000)

Domain name based visualization of Web histories in a zoomable user interface - Gandhi,R.; Kumar,G.; Bederson, Benjamin B.; Shneiderman, Ben (11th International Workshop on Database and Expert Systems Applications, 2000. Proceedings, 2000)
Users of hypertext systems like the World Wide Web (WWW) often find themselves following hypertext links deeper and deeper, only to find themselves “lost” and unable to find their way back to the previously visited pages. We have implemented a Web browser companion called Domain Tree Browser (DTB) that builds a tree structured visual navigation history while browsing the Web. The Domain Tree Browser organizes the URLs visited based on the domain name of each URL and shows thumbnails of each page in a zoomable window
Keywords: Computer science; data visualisation; domain name; domain name based visualization; Domain Tree Browser; Educational institutions; History; hypermedia; hypertext links; hypertext systems; information resources; Navigation; online front-ends; thumbnails; Tree graphs; tree structured visual navigation history; Uniform resource locators; URLs; User interfaces; Visualization; Web browser companion; Web histories; Web pages; World Wide Web; zoomable user interface; zoomable window

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

Embedded multiprocessors: Scheduling and synchronization - Sriram,S.; Bhattacharyya, Shuvra S. (CRC, 2000)

The experimental validation and packaging of software technologies - Shull, Forrest; Basili, Victor R.; Zelkowitz, Marvin V (ACM SIGSOFT Software Engineering Notes, 2000)

A first step towards automated detection of buffer overrun vulnerabilities - Wagner,D.; Foster, Jeffrey S.; Brewer,E.A.; Aiken,A. (The 2000 Network and Distributed Systems Security Conference. San Diego, CA, 2000)

High performance computing algorithms for land cover dynamics using remote sensing data - Kalluri, SNV; JaJa, Joseph F.; Bader, D.A.; Zhang,Z.; Townshend,J.R.G.; Fallah-Adl,H. (International Journal of Remote Sensing, 2000)
Global and regional land cover studies need to apply complex models on selected subsets of large volumes of multi-sensor and multi-temporal data sets that have been derived from raw instrument measurements using widely accepted pre-processing algorithms. The computational and storage requirements of most of these studies far exceed what is possible on a single workstation environment. We have been pursuing a new approach that couples scalable and open distributed heterogeneous hardware with the development of high performance software for processing, indexing and organizing remotely sensed data. Hierarchical data management tools are used to ingest raw data, create metadata and organize the archived data so as to automatically achieve computational load balancing among the available nodes and minimize input/output overheads. We illustrate our approach with four specific examples. The first is the development of the first fast operational scheme for the atmospheric correction of Landsat Thematic Mapper scenes, while the second example focuses on image segmentation using a novel hierarchical connected components algorithm. Retrieval of the global Bidirectional Reflectance Distribution Function in the red and near-infrared wavelengths using four years (1983 to 1986) of Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land data is the focus of our third example. The fourth example is the development of a hierarchical data organization scheme that allows on-demand processing and retrieval of regional and global AVHRR data sets. Our results show that substantial reductions in computational times can be achieved by the high performance computing technology.

In search of illumination invariants - Chen,H. F; Belhumeur,P. N.; Jacobs, David W. (Computer Vision and Pattern Recognition, 2000. Proceedings. IEEE Conference on, 2000)
We consider the problem of determining functions of an image of an object that are insensitive to illumination changes. We first show that for an object with Lambertian reflectance there are no discriminative functions that are invariant to illumination. This result leads as to adopt a probabilistic approach in which we analytically determine a probability distribution for the image gradient as a function of the surface's geometry and reflectance. Our distribution reveals that the direction of the image gradient is insensitive to changes in illumination direction. We verify this empirically by constructing a distribution for the image gradient from more than 20 million samples of gradients in a database of 1,280 images of 20 inanimate objects taken under varying lighting condition. Using this distribution we develop an illumination insensitive measure of image comparison and test it on the problem of face recognition
Keywords: comparison; image; gradient; face; invariants; image; Lambertian; recognition; recognition; illumination; recognition; object; reflectance; face

Jazz: an extensible zoomable user interface graphics toolkit in Java - Bederson, Benjamin B.; Meyer,J.; Good,L. (Proceedings of the 13th annual ACM symposium on User interface software and technology, 2000)

Kronos: A software system for the processing and retrieval of large-scale AVHRR data sets - Zhang,Z.; JaJa, Joseph F.; Bader, D.A.; Kalluri, SNV; Song,H.; El Saleous,N.; Vermote,E.; Townshend,J.R.G. (PE & RS- Photogrammetric Engineering and Remote Sensing, 2000)
Raw remotely sensed satellite data have to be processed andmapped into a standard projection in order to produce a multi- temporal data set which can then be used for regional or global Earth science studies. However, traditional methods of processing remotely sensed satellite data have inherent limitations because they are based on a fixed processing chain. Different users may need the data in different forms with possibly different processing steps; hence, additional transformations may have to be applied to the processed data, resulting in potentially significant errors. In this paper, we describe a software system, Kronos, for the generation of custom-tailored products from the Advanced Very High Resolution Radiometer (AVHRR) sensor. It allows the generation of a rich set of products that can be easily specified through a simple interface by scientists wishing to carry out Earth system modeling or analysis. Kronos is based on a flexible methodology and consists of four major components: ingest and preprocessing, indexing and storage, a search and processing engine, and a Java interface. After geo-location and calibration, every pixel is indexed and stored using a combination of data structures. Following the users' queries, data are selectively retrieved and secondary processing such as atmospheric correction, compositing, and projection are performed as specified. The processing is divided into two stages, the first of which involves the geo-location and calibration of the remotely sensed data and, hence, results in no loss of information. The second stage involves the retrieval of the appropriate data subsets and the application of the secondary processing specified by the user. This scheme allows the indexing and the storage of data from different sensors without any loss of information and, therefore, allows assimilation of data from multiple sensors. User specified processing can be applied later as needed.

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

The Loading Time Scheduling Problem - Bhatia,Randeep; Khuller, Samir; Naor,Joseph (Seffi) (Journal of Algorithms, 2000)
In this paper we study precedence constrained scheduling problems, where the tasks can only be executed on a specified subset of the set of machines. Each machine has a loading time that is incurred only for the first task that is scheduled on the machine in a particular run. This basic scheduling problem arises in the context of machining on numerically controlled machines and query optimization in databases and in other artificial intelligence applications. We give the first nontrivial approximation algorithm for this problem. We also prove nontrivial lower bounds on best possible approximation ratios for these problems. These improve on the nonapproximability results that are implied by the nonapproximability results for the shortest common supersequence problem. We use the same algorithm technique to obtain approximation algorithms for a problem arising in the context of code generation for parallel machines and for the weighted shortest common supersequence problem.

On local search and placement of meters in networks - Khuller, Samir; Bhatia,Randeep; Pless,Robert (Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms, 2000)

Multi-camera networks: eyes from eyes - Fermüller, Cornelia; Aloimonos, J.; Baker, P.; Pless, R.; Neumann, J.; Stuart, B. (IEEE Workshop on Omnidirectional Vision, 2000. Proceedings, 2000)
Autonomous or semi-autonomous intelligent systems, in order to function appropriately, need to create models of their environment, i.e., models of space time. These are descriptions of objects and scenes and descriptions of changes of space over time, that is, events and actions. Despite the large amount of research on this problem, as a community we are still far from developing robust descriptions of a system's spatiotemporal environment using video input (image sequences). Undoubtedly, some progress has been made regarding the understanding of estimating the structure of visual space, but it has not led to solutions to specific applications. There is, however, an alternative approach which is in line with today's “zeitgeist.” The vision of artificial systems can be enhanced by providing them with new eyes. If conventional video cameras are put together in various configurations, new sensors can be constructed that have much more power and the way they “see” the world makes it much easier to solve problems of vision. This research is motivated by examining the wide variety of eye design in the biological world and obtaining inspiration for an ensemble of computational studies that relate how a system sees to what that system does (i.e. relating perception to action). This, coupled with the geometry of multiple views that has flourished in terms of theoretical results in the past few years, points to new ways of constructing powerful imaging devices which suit particular tasks in robotics, visualization, video processing, virtual reality and various computer vision applications, better than conventional cameras. This paper presents a number of new sensors that we built using common video cameras and shows their superiority with regard to developing models of space and motion
Keywords: Biosensors; CAMERAS; Computer vision; Eyes; Image sequences; intelligent systems; Layout; Machine vision; Robot vision systems; Robustness; Spatiotemporal phenomena; video cameras; Virtual reality

Multidimensional exploration of software implementations for DSP algorithms - Zitzler,E.; Teich,J.; Bhattacharyya, Shuvra S. (The Journal of VLSI Signal Processing, 2000)

New eyes for building models from video - Fermüller, Cornelia; Aloimonos, J.; Brodský,Tomáš (Computational Geometry, 2000)
Models of real-world objects and actions for use in graphics, virtual and augmented reality and related fields can only be obtained through the use of visual data and particularly video. This paper examines the question of recovering shape models from video information. Given video of an object or a scene captured by a moving camera, a prerequisite for model building is to recover the three-dimensional (3D) motion of the camera which consists of a rotation and a translation at each instant. It is shown here that a spherical eye (an eye or system of eyes providing panoramic vision) is superior to a camera-type eye (an eye with restricted field of view such as a common video camera) as regards the competence of 3D motion estimation. This result is derived from a geometric/statistical analysis of all the possible computational models that can be used for estimating 3D motion from an image sequence. Regardless of the estimation procedure for a camera-type eye, the parameters of the 3D rigid motion (translation and rotation) contain errors satisfying specific geometric constraints. Thus, translation is always confused with rotation, resulting in inaccurate results. This confusion does not happen for the case of panoramic vision. Insights obtained from this study point to new ways of constructing powerful imaging devices that suit particular tasks in visualization and virtual reality better than conventional cameras, thus leading to a new camera technology. Such new eyes are constructed by putting together multiple existing video cameras in specific ways, thus obtaining eyes from eyes. For a new eye of this kind we describe an implementation for deriving models of scenes from video data, while avoiding the correspondence problem in the video sequence.
Keywords: model building; shape reconstruction; structure from motion; video analysis

New Eyes for Shape and Motion Estimation - Baker,Patrick; Pless,Robert; Fermüller, Cornelia; Aloimonos, J. (Biologically Motivated Computer VisionBiologically Motivated Computer Vision, 2000)
Motivated by the full field of view of insect eyes and their fast and accurate estimation of egomotion, we constructed a system of cameras to take advantage of the full field of view (FOV) constraints that insects use. In this paper, we develop a new ego-motion algorithm for a rigidly mounted set of cameras undergoing arbitrary rigid motion. This egomotion algorithm combines the unambiguous components of the motion computed by each separate camera. We prove that the cyclotorsion is resistant to errors and show this empirically. We show how to calibrate the system with two novel algorithms, one using secondary cameras and one using self calibration. Given this system calibration, the new 3D motion algorithm first computes the rotation and then the 3D translation. We apply this algorithm to a camera system constructed with four rigidly mounted synchronized cameras pointing in various directions and present motion estimation results at www.cfar.umd.edu/ pbaker/argus.html.

Perceptual Completion Behind Occluders: The Role of Convexity - Liu,Z.; Jacobs, David W.; Basri,R. (Perceptual Organization for Artificial Vision Systems, 2000)
An important problem in perceptual organization is to determine whether two image regions belong to the same object. In this chapter, we consider the situation when two image regions potentially group into a single object behind a common occluder. We study the extent to which two image regions are grouped more strongly than two other image regions. Existing theories in both human and computer vision have mainly emphasized the role of good continuation. Namely, the shorter and smoother the completing contours are between two image regions, the stronger the grouping will be. In contrast, Jacobs [3] has proposed a theory that considers relative positions and orientations of two image regions. For instance, the theory predicts that two image regions that can be linked by convex completing contours are grouped more strongly than those that can only be linked by concave completing contours, even though the completing contours are identical in shape. We present, in addition to our previous work (Liu, Jacobs, and Basri, 1999), human psychophysical evidence that concurs with the predictions of this theory and suggests an important role of convexity in perceptual grouping.

Receiver based management of low bandwidth access links - Spring, Neil; Chesire,M.; Berryman,M.; Sahasranaman,V.; Anderson,T.; Bershad,B. (IEEE INFOCOM 2000. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings, 2000)
In this paper, we describe a receiver-based congestion control policy that leverages TCP flow control mechanisms to prioritize mixed traffic loads across access links. We manage queueing at the access link to: (1) improve the response time of interactive network applications; (2) reduce congestion-related packet losses; while (3) maintaining high throughput for bulk-transfer applications. Our policy controls queue length by manipulating receive socket buffer sizes. We have implemented this solution in a dynamically loadable Linux kernel module, and tested it over low-bandwidth links. Our approach yields a 7-fold improvement in packet latency over an unmodified system while maintaining 94% link utilization. In the common case, congestion-related packet losses at the access link can be eliminated. Finally, by prioritizing short flows, we show that our system reduces the time to download a complex Web page during a large background transfer by a factor of two
Keywords: Bandwidth; buffer storage; bulk-transfer applications; complex Web page; congestion control policy; Delay; dynamically loadable Linux kernel module; information resources; interactive network; Internet; Kernel; link utilization; Linux; low-bandwidth access links; mixed traffic load; packet latency; queue length; queueing theory; receive socket buffer sizes; receiver-based management; response time; short flow prioritizing; Size control; Sockets; subscriber loops; TCP flow control; telecommunication congestion control; telecommunication network management; Telecommunication traffic; Testing; Throughput; Transport protocols; Unix; Web pages

Resynchronization for multiprocessor DSP systems - Bhattacharyya, Shuvra S.; Sriram,S.; Lee,E. A (Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on, 2000)

Retrieval scheduling for collaborative multimedia presentations - Bai,Ping; Prabhakaran,B.; Srinivasan, Aravind (Multimedia Systems, 2000)
The single-system approach is no longer sufficient to handle the load on popular Internet servers, especially for those offering extensive multimedia content. Such services have to be replicated to enhance their availability, performance, and reliability. In a highly replicated and available environment, server selection is an important issue. In this paper, we propose an application-layer broker (ALB) for this purpose. ALB employs a content-based, client-centric approach to negotiate with the servers and to identify the best server for the requested objects. ALB aims to maximize client buffer utilization in order to efficiently handle dynamic user interactions such as skip, reverse presentation, go back in time. We also present details of a collaborative multimedia presentation platform that we have developed based on ALB.

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

Robustly estimating changes in image appearance - Black,M. J; Fleet,D. J; Yacoob,Yaser (Computer Vision and Image Understanding, 2000)

Rotation, scale, and translation resilient public watermarking for images - Lin,C.Y.; Wu,M.; Bloom,J.A.; Cox,I.J.; Miller,M.L.; Lui,Y.M. (PROC SPIE INT SOC OPT ENG, 2000)
Many electronic watermarks for still images and video content are sensitive to geometric distortions. For example,simple rotation, scaling, and/or translation (RST) of an image can prevent detection of a public watermark. In this paper, we propose a watermarking algorithm that is robust to RST distortions. The watermark is embedded into a 1-dimensional signal obtained by first taking the Fourier transform of the image, resampling the Fourier magnitudes into log-polar coordinates, and then summing a function of those magnitudes along the log-radius axis. If the image is rotated, the resulting signal is cyclically shifted. If it is scaled, the signal is multiplied by some value. And if the image is translated, the signal is unaffected. We can therefore compensate for rotation with a simple search, and for scaling by using the correlation coefficient for the detection metric. False positive results on a database of 10,000 images are reported. Robustness results on a database of 2,000 images are described. It is shown that the watermark is robust to rotation, scale and translation. In addition, the algorithm shows resistance to cropping.

Structure from motion: Beyond the epipolar constraint - Brodskỳ, T.; Fermüller, Cornelia; Aloimonos, J. (International Journal of Computer Vision, 2000)

Systematic consolidation of input and output buffers in synchronous dataflow specifications - Murthy,P. K; Bhattacharyya, Shuvra S. (Signal Processing Systems, 2000. SiPS 2000. 2000 IEEE Workshop on, 2000)

Using hardware performance monitors to isolate memory bottlenecks - Buck, B. R; Hollingsworth, Jeffrey K (Proceedings of the 2000 ACM/IEEE conference on Supercomputing (CDROM), 2000)

Vehicle Speed Information Displays for Public Websites A Survey of User Preferences - Plaisant, Catherine; Bhamidipati,Phanikumar (Technical Reports from UMIACS, 2000)
The paper reports on a study comparing alternative presentations offreeway speed data on maps. The goal of the study was to inform the design of displays of real time speed data over the Internet to the general public. Subjects were presented with a series of displays and asked to rate their preferences. We looked at different choices of color (3 colors, 6 colors or a continuous range), and proposed line, sensor, and segment representations of the speed data. We also collected feedback on more complex displays such as comparison between current and "normal" speeds, and a chart of speed variation over a period of time at given locations. (Also cross-referenced as HCIL-TR-2000-23) (Also cross-referenced as UMIACS-TR-2000-73)
Keywords: Technical Report

Web Query Optimizer - Zadorozhny,Vladimir; Bright,Laura; Raschid, Louiqa; Urhan,Tolga; Vidal,Maria Esther (Data Engineering, International Conference on, 2000)
We demonstrate a Web Query Optimizer (WQO) within an architecture of mediators and wrappers, for WebSources of limited capability in a wide area environment. The WQO has several innovative features including a CBR (capability based rewriting) Tool, an enhanced randomized relational optimizer extended to a Web environment, and a WebWrapper cost model that can provide relevant metrics for accessing WebSources. The prototype has been tested against a number of WebSources.

3-d to 2-d pose determination with regions - Jacobs, David W.; Basri,R. (International Journal of Computer Vision, 1999)
This paper presents a novel approach to parts-based object recognition in the presence of occlusion. We focus on the problem of determining the pose of a 3-D object from a single 2-D image when convex parts of the object have been matched to corresponding regions in the image. We consider three types of occlusions: self-occlusion, occlusions whose locus is identified in the image, and completely arbitrary occlusions. We show that in the first two cases this is a convex optimization problem, derive efficient algorithms, and characterize their performance. For the last case, we prove that the problem of finding valid poses is computationally hard, but provide an efficient, approximate algorithm. This work generalizes our previous work on region-based object recognition, which focused on the case of planar models.

Advances in spherical harmonic device modeling: calibration and nanoscale electron dynamics - Lin,Chung-Kai; Goldsman,N.; Mayergoyz, Issak D; Aronowitz,S.; Belova,N. (Simulation of Semiconductor Processes and Devices, 1999. SISPAD '99. 1999 International Conference on, 1999)
Improvements in the Spherical Harmonic (SH) method for solving Boltzmann Transport Equation (BTE) are presented. The simulation results provide the same physical detail as analytical band Monte Carlo (MC) calculations, and are obtained approximately a thousand times faster. A new physical model for surface scattering has also been developed. As a result, the SHBTE model achieves calibration for a complete process of I-V characteristics and substrate current consistently for the first time
Keywords: Boltzmann; characteristics; SHBTE; current; surface; device; dynamics; spherical; electron; equation; calibration; semiconductor; equation; I-V; harmonic; model; substrate; models; surface; scattering; scattering; Boltzmann; simulation; calibration; nanoscale; transport

Application-layer broker for scalable Internet services with resource reservation - Bai,Ping; Prabhakaran,B.; Srinivasan, Aravind (Proceedings of the seventh ACM international conference on Multimedia (Part 2), 1999)

Building dependable distributed applications using AQUA - Ren,J.; Michel Cukier; Rubel,P.; Sanders,W. H.; Bakken,D. E.; Karr,D. A. (1999)
Building dependable distributed systems using ad hoc methods is a challenging task. Without proper support, an application programmer must face the daunting requirement of having to provide fault tolerance at the application level, in addition to dealing with the complexities of the distributed application itself. This approach requires a deep knowledge of fault tolerance on the part of the application designer, and has a high implementation cost. What is needed is a systematic approach to providing dependability to distributed applications. Proteus, part of the AQuA architecture, fills this need and provides facilities to make a standard distributed CORBA application dependable, with minimal changes to an application. Furthermore, it permits applications to specify, either directly or via the Quality Objects (QuO) infrastructure, the level of dependability they expect of a remote object, and will attempt to configure the system to achieve the requested dependability level. Our previous papers have focused on the architecture and implementation of Proteus. This paper describes how to construct dependable applications using the AQuA architecture, by describing the interface that a programmer is presented with and the graphical monitoring facilities that it provides
Keywords: ad hoc methods; application programmer; AQuA; complexities; computational complexity; dependable distributed applications; distributed CORBA application; distributed object management; Fault tolerance; fault tolerant computing; proteus

Building dependable distributed objects with the AQuA architecture - Michel Cukier; Ren,J.; Rubel,P.; Bakken,D. E.; Karr,D. A. (1999)

Designing PETS: a personal electronic teller of stories - Druin, Allison; Montemayor,Jamie; Hendler,Jim; McAlister,Britt; Boltman,Angela; Fiterman,Eric; Plaisant,Aurelie; Kruskal,Alex; Olsen,Hanne; Revett,Isabella; Schwenn,Thomas Plaisant; Sumida,Lauren; et al. (Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit, 1999)
We have begun the development of a new robotic pet that cansupport children in the storytelling process. Children can build their own pet by snapping together the modular animal parts of the PETS robot. After their pet is built, children can tell stories using the My Pets software. These stories can then be acted out by their robotic pet. This video paper describes the motivation for this research and the design process of our intergenerational design team in building the first PETS prototypes. We will discuss our progress to date and our focus for the future.
Keywords: children; cooperative inquiry; design techniques; educational applications; intergenerational design team; PETS; ROBOTICS

Does animation help users build mental maps of spatial information? - Bederson, Benjamin B.; Boltman,A. (Information Visualization, 1999.(Info Vis' 99) Proceedings. 1999 IEEE Symposium on, 1999)

Does zooming improve image browsing - Tammara,T.A.C.; Bederson, Benjamin B. (Proceedings of the fourth ACM conference on Digital libraries, 1999)

Efficient perspective-accurate silhouette computation - Barequet,G.; Duncan,C. A; Goodrich,M. T; Kumar,S.; Pop, Mihai (Proceedings of the fifteenth annual symposium on Computational geometry, 1999)

A hierarchical data archiving and processing system to generate custom tailored products from AVHRR data - Kalluri, SNV; Zhang,Z.; JaJa, Joseph F.; Bader, D.A.; Song,H.; El Saleous,N.; Vermote,E.; Townshend,J.R.G. (Geoscience and Remote Sensing Symposium, 1999. IGARSS '99 Proceedings. IEEE 1999 International, 1999)
A novel indexing scheme is described to catalogue satellite data on a pixel basis. The objective of this research is to develop an efficient methodology to archive, retrieve and process satellite data, so that data products can be generated to meet the specific needs of individual scientists. When requesting data, users can specify the spatial and temporal resolution, geographic projection, choice of atmospheric correction, and the data selection methodology. The data processing is done in two stages. Satellite data is calibrated, navigated and quality flags are appended in the initial processing. This processed data is then indexed and stored. Secondary processing such as atmospheric correction and projection are done after a user requests the data to create custom made products. By dividing the processing in to two stages saves time, since the basic processing tasks such as navigation and calibration which are common to all requests are not repeated when different users request satellite data. The indexing scheme described can be extended to allow fusion of data sets from different sensors
Keywords: archiving; image; AVHRR; GIS; PACS; custom; data; image; land; image; remote; mapping; mapping; PACS; geophysical; measurement; PROCESSING; processing; geophysical; product; data; remote; scheme; infrared; sensing; optical; sensing; terrain; signal; surface; multispectral; system; indexing; tailored; technique; hierarchical; techniques; remote

Human-centered computing, online communities, and virtual environments - Brown,J. R; van Dam,A.; Earnshaw,R.; Encarnacao,J.; Guedj,R.; Preece,J.; Shneiderman, Ben; Vince,J. (IEEE Computer Graphics and Applications, 1999)
This report summarizes results of the first EC/NSF joint Advanced Research Workshop, which identified key research challenges and opportunities in information technology. The group agreed that the first joint research workshop should concentrate on the themes of human-centered computing and VEs. Human-centered computing is perceived as an area of strategic importance because of the move towards greater decentralization and decomposition in the location and provision of computation. The area of VEs is one where increased collaboration should speed progress in solving some of the more intractable problems in building effective applications
Keywords: Books; Collaboration; Collaborative work; Conferences; EC/NSF joint Advanced Research Workshop; Feeds; Human computer interaction; human-centered computing; Internet; Joining materials; Laboratories; Online communities; Research initiatives; USA Councils; User interfaces; Virtual environment; virtual environments; Virtual reality

Independent motion: the importance of history - Pless, R.; Brodsky, T.; Aloimonos, J. (Computer Vision and Pattern Recognition, 1999. IEEE Computer Society Conference on., 1999)
We consider a problem central in aerial visual surveillance applications-detection and tracking of small, independently moving objects in long and noisy video sequences. We directly use spatiotemporal image intensity gradient measurements to compute an exact model of background motion. This allows the creation of accurate mosaics over many frames and the definition of a constraint violation function which acts as an indication of independent motion. A novel temporal integration method maintains confidence measures over long subsequences without computing the optic flow, requiring object models, or using a Kalman filler. The mosaic acts as a stable feature frame, allowing precise localization of the independently moving objects. We present a statistical analysis of the effects of image noise on the constraint violation measure and find a good match between the predicted probability distribution function and the measured sample frequencies in a test sequence
Keywords: aerial visual surveillance; background image; Fluid flow measurement; Frequency measurement; History; Motion detection; Motion estimation; Motion measurement; Noise measurement; Optical computing; Optical noise; spatiotemporal image intensity gradient measurements; Spatiotemporal phenomena; Surveillance; Video sequences

Interface and data architecture for query preview in networked information systems - Plaisant, Catherine; Shneiderman, Ben; Doan,Khoa; Bruns,Tom (ACM Trans. Inf. Syst., 1999)
There are numerous problems associated with formulating queries onnetworked information systems. These include increased data volume and complexity, accompanied by slow network access. This article proposes a new approach to a network query user interfaces that consists of two phases: query preview and query refinement. This new approach is based on the concepts of dynamic queries and query previews, which guides users in rapidly and dynamically eliminating undesired records, reducing the data volume to a manageable size, and refining queries locally before submission over a network. Examples of two applications are given: a Restaurant Finder and a prototype for NASA's Earth Observing Systems Data Information Systems (EOSDIS). Data architecture is discussed, and user feedback is presented.
Keywords: direct manipulation; dynamic query; EOSDIS; graphical user interface; query preview; query refinement; science data

Machine Translation - Bel,N.; Dorr, Bonnie J; Hovy,E.; Knight,K.; Iida,H.; Boitet,C.; Maegaard,B.; Wilks,Y. (Multilingual Information Management: Current Levels and Future Abilities, 1999)

Model-checking concurrent systems with unbounded integer variables: symbolic representations, approximations, and experimental results - Bultan,Tevfik; Gerber,Richard; Pugh, William (ACM Transactions on Programming Languages and SystemsACM Trans. Program. Lang. Syst., 1999)

Motion Segmentation: A Synergistic Approach - Fermüller, Cornelia; Brodsky, Tomas; Aloimonos, J. (Computer Vision and Pattern Recognition, IEEE Computer Society Conference on, 1999)
Since estimation of camera motion requires knowledge of independent motion, and moving object detection and localization requires knowledge about the camera motion, the two problems of motion estimation and segmentation need to be solved together in a synergistic manner. This paper provides an approach to treating both these problems simultaneously. The technique introduced here is based on a novel concept, ``scene ruggedness,'' which parameterizes the variation in estimated scene depth with the error in the underlying three-dimensional (3D) motion. The idea is that incorrect 3D motion estimates cause distortions in the estimated depth map, and as a result smooth scene patches are computed as rugged surfaces. The correct 3D motion can be distinguished, as it does not cause any distortion and thus gives rise to the background patches with the least depth variation between depth discontinuities, with the locations corresponding to independent motion being rugged. The algorithm presented employs a binocular observer whose nature is exploited in the extraction of depth discontinuities, a step that facilitates the overall procedure, but the technique can be extended to a monocular observer in a variety of ways.
Keywords: epipolar minimization; independent motion detection; Motion analysis

Network Programming Using PLAN - Hicks, Michael W.; Kakkar,Pankaj; Moore,Jonathan; Gunter,Carl; Nettles,Scott (Internet Programming LanguagesInternet Programming Languages, 1999)
We present here a methodology for programming active networks in the environment defined by our new language PLAN (Packet Language for Active Networks). This environment presumes a two-level architecture consisting of: 1. active packets carrying PLAN code; and 2. downloadable, node-resident services written in more general-purpose languages. We present several examples which illustrate how these two features can be combined to implement various network functions.

Object-relational queries into multidimensional databases with the active data repository - Ferreira,R.; Kurc, T.; Beynon, M.; Chang,C.; Sussman, Alan; Saltz,J. H (Parallel Processing Letters, 1999)

OSMA Software Program: Domain Analysis Guidebook - Basili, Victor R.; Seaman,Carolyn; Tesoriero,Roseanne; Zelkowitz, Marvin V (Technical Reports from UMIACS, UMIACS-TR-99-16, 1999)
Domain analysis is the process of identifying and organizing knowledge abouta class of problems. This guidebook presents a method of performing experience domain analysis in software development organizations. The purpose of the guidebook is to facilitate the reader in characterizing two given development environments, applying domain analysis to model each, and then applying an evaluation process, based upon the Goal/Metric/Paradigm, to transfer a given development technology from one of the environments to the other. This guidebook describes this process and gives an example of its use within NASA. Also cross-referenced as UMIACS-TR-99-16
Keywords: Technical Report

Perceptual Organization in Computer Vision - Boyer,K.L.; Sarkar,S.; Feldman,J.; Granlund,G.; Horaud,R.; Hutchinson,S.; Jacobs, David W.; Kak,A.; Lowe,D.; Malik,J. (Academic Press, 1999)

Performance impact of proxies in data intensive client-server applications - Beynon,M. D; Sussman, Alan; Saltz, J. (Proceedings of the 13th international conference on Supercomputing, 1999)

Perspective-based Usability Inspection: An Empirical Validation of Efficacy - Zhang,Zhijun; Basili, Victor R.; Shneiderman, Ben (Empirical Software Engineering, 1999)
Inspection is a fundamental means of achieving software usability. Past research showed that the current usability inspection techniques were rather ineffective. We developed perspective-based usability inspection, which divides the large variety of usability issues along different perspectives and focuses each inspection session on one perspective. We conducted a controlled experiment to study its effectiveness, using a post-test only control group experimental design, with 24 professionals as subjects. The control group used heuristic evaluation, which is the most popular technique for usability inspection. The experimental design and the results are presented, which show that inspectors applying perspective-based inspection not only found more usability problems related to their assigned perspectives, but also found more overall problems. Perspective-based inspection was shown to be more effective for the aggregated results of multiple inspectors, finding about 30% more usability problems for 3 inspectors. A management implication of this study is that assigning inspectors more specific responsibilities leads to higher performance. Internal and external threats to validity are discussed to help better interpret the results and to guide future empirical studies.

A practical approach to implementing real-time semantics - Bhat,G.; Cleaveland, Rance; L\üttgen,G. (Annals of Software Engineering, 1999)

Proteus: a flexible infrastructure to implement adaptive fault tolerance in AQuA - Sabnis,C.; Michel Cukier; Ren,J.; Rubel,P.; Sanders,W. H.; Bakken,D. E.; Karr,D. (1999)
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, providing a high-level method for applications to specify their desired dependability, and providing a dependability manager that attempts to reconfigure a system at runtime so that dependability requests are satisfied. This paper describes how dependability is provided in AQuA. In particular it describes Proteus, the part of AQuA that dynamically manages replicated distributed objects to make them dependable. Given a dependability request, Proteus chooses a fault tolerance approach and reconfigures the system to try to meet the request. The infrastructure of Proteus is described in this paper, along with its use in implementing active replication and a simple dependability policy
Keywords: adaptive fault tolerance; AQuA; commercial off-the-shelf components; CORBA applications; cost; dependable distributed systems; distributed object management; object replication; proteus; reconfigurable architectures; Runtime; Software architecture; software fault tolerance

Refining query previews techniques for data with multivalued attributes: the case of NASA EOSDIS - Plaisant, Catherine; Venkatraman,M.; Ngamkajorwiwat,K.; Barth,R.; Harberts,B.; Feng,Wenlan (Research and Technology Advances in Digital Libraries, 1999. ADL '99. Proceedings. IEEE Forum on, 1999)
Query Previews allow users to rapidly gain an understanding of the content and scope of a digital data collection. These previews present overviews of abstracted metadata, enabling users to rapidly and dynamically avoid undesired data. We present our recent work on developing query previews for a variety of NASA EOSDIS situations. We focus on approaches that successfully address the challenge of multi-valued attribute data. Memory requirements and processing time associated with running these new solutions remain independent of the number of records in the dataset. We describe two techniques and their respective prototypes used to preview NASA Earth science data
Keywords: attribute; attributes; processing; collection; memory; computing; meta; data; data; abstracted; data; digital; data; multivalued; data; query; Earth; EOSDIS; NASA; libraries; geophysics; metadata; dataset; digital; NASA; previews; processing; requirements; multi-valued; Science; techniques; undesired; time; query

The role of convexity in perceptual completion: beyond good continuation - Liu,Zili; Jacobs, David W.; Basri,Ronen (Vision Research, 1999)
Since the seminal work of the Gestalt psychologists, there has been great interest in understanding what factors determine the perceptual organization of images. While the Gestaltists demonstrated the significance of grouping cues such as similarity, proximity and good continuation, it has not been well understood whether their catalog of grouping cues is complete — in part due to the paucity of effective methodologies for examining the significance of various grouping cues. We describe a novel, objective method to study perceptual grouping of planar regions separated by an occluder. We demonstrate that the stronger the grouping between two such regions, the harder it will be to resolve their relative stereoscopic depth. We use this new method to call into question many existing theories of perceptual completion (Ullman, S. (1976). Biological Cybernetics, 25, 1–6; Shashua, A., & Ullman, S. (1988). 2nd International Conference on Computer Vision (pp. 321–327); Parent, P., & Zucker, S. (1989). IEEE Transactions on Pattern Analysis and Machine Intelligence, 11, 823–839; Kellman, P. J., & Shipley, T. F. (1991). Cognitive psychology, Liveright, New York; Heitger, R., & von der Heydt, R. (1993). A computational model of neural contour processing, figure-ground segregation and illusory contours. In Internal Conference Computer Vision (pp. 32–40); Mumford, D. (1994). Algebraic geometry and its applications, Springer, New York; Williams, L. R., & Jacobs, D .W. (1997). Neural Computation, 9, 837–858) that are based on Gestalt grouping cues by demonstrating that convexity plays a strong role in perceptual completion. In some cases convexity dominates the effects of the well known Gestalt cue of good continuation. While convexity has been known to play a role in figure/ground segmentation (Rubin, 1927; Kanizsa & Gerbino, 1976), this is the first demonstration of its importance in perceptual completion.
Keywords: Amodal completion; Convexity; Good continuation; Grouping; Stereoscopic depth

A rotation, scale and translation resilient public watermark - Wu,M.; Miller,M.L.; Bloom,J.A.; Cox,I.J. (Acoustics, Speech, and Signal Processing, 1999. Proceedings., 1999 IEEE International Conference on, 1999)
Summary form only given. Watermarking algorithms that are robust to the common geometric transformations of rotation, scale and translation (RST) have been reported for cases in which the original unwatermarked content is available at the detector so as to allow the transformations to be inverted. However, for public watermarks the problem is significantly more difficult since there is no original content to register with. Two classes of solution have been proposed. The first embeds a registration pattern into the content while the second seeks to apply detection methods that are invariant to these geometric transformations. This paper describes a public watermarking method which is invariant (or bares a simple relation) to the common geometric transforms of rotation, scale, and translation. It is based on the Fourier-Mellin transform which has previously been suggested. We extend this work, using a variation based on the Radon transform. The watermark is inserted into a projection of the image. The properties of this projection are such that RST transforms produce simple or no effects on the projection waveform. When a watermark is inserted into a projection, the signal must eventually be back projected to the original image dimensions. This is a one to many mapping that allows for considerable flexibility in the watermark insertion process. We highlight some theoretical and practical issues that affect the implementation of an RST invariant watermark. Finally, we describe preliminary experimental results
Keywords: algorithms; Fourier; coding; coding; image; data; transform; dimensions; projection; Fourier-Mellin; image; invariant; methods; detector; experimental; of; pattern; rotation; projection; mapping; original; public; registration; security; resilient; results; geometric; transform; detection; transform; RST; transformations; image; transforms; image; transforms; Radon; watermark; RST; watermark; scale; watermark; translation; watermark; watermarking; waveform; registration

Running EveryWare on the computational grid - Wolski,R.; Brevik,J.; Krintz,C.; Obertelli,G.; Spring, Neil; Su,A. (Proceedings of the 1999 ACM/IEEE conference on Supercomputing (CDROM), 1999)

Shape from Video - Brodsky, Tomas; Fermüller, Cornelia; Aloimonos, J. (Computer Vision and Pattern Recognition, IEEE Computer Society Conference on, 1999)
This paper presents a novel technique for recovering the shape of a static scene from a video sequence due to a rigidly moving camera. The solution procedure consists of two stages. In the first stage, the rigid motion of the camera at each instant in time is recovered. This provides the transformation between successive viewing positions. The solution is achieved through new constraints which relate 3D motion and shape directly to the image derivatives. These constraints allow the combination of the processes of 3D motion estimation and segmentation by exploiting the geometry and statistics inherent in the data. In the second stage the scene surfaces are reconstructed through an optimization procedure which utilizes data from all the frames of a short video sequence. A number of experimental results demonstrate the potential of the approach.
Keywords: epipolar minimization; model extraction; Motion analysis; vision and graphics

Sheet metal bending: generating shared setups - Gupta,S.K.; Bourne,D. A. (TRANSACTIONS-AMERICAN SOCIETY OF MECHANICAL ENGINEERS JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING, 1999)
Contemporary process planners for sheet metal bending solve the process planning problemfor individual parts. Quite often, many different parts can be produced on shared setups. However, plans generated by current process planning systems fail to exploit this commonality between setups and try to generate optimal setups for individual parts. In this paper, we present an algorithm for multi-part setup planning for sheet metal bending. This algorithm takes a set of parts and operation sequences for these parts, and tries to find a shared setup plan that can work for every part in the set. Setup changes constitute a major portion of the production time in batch production environments. Therefore, multi-part setup planning techniques can be used to significantly cut down the total number of setups and increase the overall through-put.

Simple: A Methodology for Programming High Performance Algorithms on Clusters of Symmetric Multiprocessors (SMPs) - Bader,David A.; JaJa, Joseph F. (Journal of Parallel and Distributed Computing, 1999)
We describe a methodology for developing high performance programs running on clusters of SMP nodes. The SMP cluster programming methodology is based on a small prototype kernel (Simple) of collective communication primitives that make efficient use of the hybrid shared and message-passing environment. We illustrate the power of our methodology by presenting experimental results for sorting integers, two-dimensional fast Fourier transforms (FFT), and constraint-satisfied searching. Our testbed is a cluster of DEC AlphaServer 2100 4/275 nodes interconnected by an ATM switch.
Keywords: cluster computing; communication primitives; experimental parallel algorithms; message passing (MPI); Parallel algorithms; parallel performance; shared memory; symmetric multiprocessors (SMP)

Single display groupware: a model for co-present collaboration - Stewart,J.; Bederson, Benjamin B.; Druin, Allison (Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit, 1999)

A Survey of Current Paradigms in Machine Translation - Dorr, Bonnie J; Jordan,Pamela W.; Benoit,John W. (Advances in Computers, 1999)
This paper is a survey of the current machine translation research in the US, Europe and Japan. A short history of machine translation is presented first, followed by an overview of the current research work. Representative examples of a wide range of different approaches adopted by machine translation researchers are presented. These are described in detail along with a discussion of the practicalities of scaling up these approaches for operational environments. In support of this discussion, issues in, and techniques for, evaluating machine translation systems are addressed.

Synthesis of embedded software from synchronous dataflow specifications - Bhattacharyya, Shuvra S.; Murthy,P. K; Lee,E. A (The Journal of VLSI Signal Processing, 1999)

TennisViewer: A Browser for Competition Trees - Johnson,B.; Shneiderman, Ben; Baker,MJ; Eick,SG (Readings in information visualization: using vision to think, 1999)

A Theory of Efficiency for Markovian Processes - Bernardo,M.; Cleaveland, Rance (University of Bologna, 1999)

XMT-M: A Scalable Decentralized Processor - Berkovich,Efraim; Nuzman,Joseph; Franklin,Manoj; Jacob,Bruce; Vishkin, Uzi (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1999)
A defining challenge for research in computer science and engineering hasbeen the ongoing quest for reducing the completion time of a single computation task. Even outside the parallel processing communities, there is little doubt that the key to further progress in this quest is to do parallel processing of some kind. A recently proposed parallel processing framework that spans the entire spectrum from (parallel) algorithms to architecture to implementation is the explicit multi-threading (XMT) framework. This framework provides: (i) simple and natural parallel algorithms for essentially every general-purpose application, including notoriously difficult irregular integer applications, and (ii) a multi-threaded programming model for these algorithms which allows an ``independence-of-order'' semantics: every thread can proceed at its own speed, independent of other concurrent threads. To the extent possible, the XMT framework uses established ideas in parallel processing. This paper presents XMT-M, a microarchitecture implementation of the XMT model that is possible with current technology. XMT-M offers an engineering design point that addresses four concerns: buildability, programmability, performance, and scalability. The XMT-M hardware is geared to execute multiple threads in parallel on a single chip: relying on very few new gadgets, it can execute parallel threads without busy-waits! Existing code can be run on XMT-M as a single thread without any modifications, thereby providing backward compatibility for commercial acceptance. Simulation-based studies of XMT-M demonstrate considerable improvements in performance relative to the best serial processor even for small, and therefore practical, input sizes. (Also cross-referenced as UMIACS-TR-99-55)
Keywords: Technical Report

AQuA: an adaptive architecture that provides dependable distributed objects - Cukier, Michel; Ren,J.; Sabnis,C.; Henke,D.; Pistole,J.; Sanders,W. H.; Bakken,D. E.; Berman,M.E.; Karr,D. A.; Schantz,R.E. (Seventeenth IEEE Symposium on Reliable Distributed Systems, 1998)
Dependable distributed systems are difficult to build. This is particularly true if they have dependability requirements that change during the execution of an application, and are built with commercial off-the-shelf hardware. In that case, fault tolerance must be achieved using middleware software, and mechanisms must be provided to communicate the dependability requirements of a distributed application to the system and to adapt the system's configuration to try to achieve the desired dependability. The AQuA architecture allows distributed applications to request a desired level of availability using the Quality Objects (QuO) framework and includes a dependability manager that attempts to meet requested availability levels by configuring the system in response to outside requests and changes in system resources due to faults. The AQuA architecture uses the QuO runtime to process and invoke availability requests, the Proteus dependability manager to configure the system in response to faults and availability requests, and the Ensemble protocol stack to provide group communication services. Furthermore, a CORBA interface is provided to application objects using the AQuA gateway. The gateway provides a mechanism to translate between process-level communication, as supported by Ensemble, and IIOP messages, understood by Object Request Brokers. Both active and passive replication are supported, and the replication type to use is chosen based on the performance and dependability requirements of particular distributed applications
Keywords: adaptive architecture; AQuA; availability requests; client-server systems; commercial off-the-shelf hardware; CORBA; dependability manager; dependability requirements; dependable distributed objects; distributed object management; Ensemble protocol stack; Fault tolerance; group communication services; middleware software; Object Request Brokers; process-level communication; proteus; Quality Objects; replication; software fault tolerance; Software quality

Beyond the Epipolar Constraint: Integrating 3D Motion and Structure Estimation - Brodský,Tomáš; Fermüller, Cornelia; Aloimonos, J. (3D Structure from Multiple Images of Large-Scale Environments3D Structure from Multiple Images of Large-Scale Environments, 1998)
This paper develops a novel solution to the problem of recovering the structure of a scene given an uncalibrated video sequence depicting the scene. The essence of the technique lies in a method for recovering the rigid transformation between the different views in the image sequence. Knowledge of this 3D motion allows for self-calibration and for subsequent recovery of 3D structure. The introduced method breaks away from applying only the traditionally used epipolar constraint and introduces a new constraint based on the interaction between 3D motion and shape. Up to now, structure from motion algorithms proceeded in two well defined steps, where the first and most important step is recovering the rigid transformation between two views, and the subsequent step is using this transformation to compute the structure of the scene in view. Here both aforementioned steps are accomplished in a synergistic manner. Existing approaches to 3D motion estimation are mostly based on the use of optic flow which however poses a problem at the locations of depth discontinuities. If we knew where depth discontinuities were, we could (using a multitude of approaches based on smoothness constraints) estimate accurately flow values for image patches corresponding to smooth scene patches; but to know the discontinuities requires solving the structure from motion problem first. In the past this dilemma has been addressed by improving the estimation of flow through sophisticated optimization techniques, whose performance often depends on the scene in view. In this paper the main idea is based on the interaction between 3D motion and shape which allows us to estimate the 3D motion while at the same time segmenting the scene. If we use a wrong 3D motion estimate to compute depth, then we obtain a distorted version of the depth function. The distortion, however, is such that the worse the motion estimate, the more likely we are to obtain depth estimates that are locally unsmooth, i.e., they vary more than the correct ones. Since local variability of depth is due either to the existence of a discontinuity or to a wrong 3D motion estimate, being able to differentiate between these two cases provides the correct motion, which yields the “smoothest” estimated depth as well as the image locations of scene discontinuities. Although no optic flow values are computed, we show that our algorithm is very much related to minimizing the epipolar constraint when the scene in view is smooth. When however the imaged scene is not smooth, the introduced constraint has in general different properties from the epipolar constraint and we present experimental results with real sequences where it performs better.

Clustering appearances of 3D objects - Basri,R.; Roth,D.; Jacobs, David W. (Computer Vision and Pattern Recognition, 1998. Proceedings. 1998 IEEE Computer Society Conference on, 1998)
We introduce a method for unsupervised clustering of images of 3D objects. Our method examines the space of all images and partitions the images into sets that form smooth and parallel surfaces in this space. It further uses sequences of images to obtain more reliable clustering. Finally, since our method relies on a non-Euclidean similarity measure we introduce algebraic techniques for estimating local properties of these surfaces without first embedding the images in a Euclidean space. We demonstrate our method by applying it to a large database of images
Keywords: 3D; clustering; image; clustering; sequences; images; unsupervised; objects; local; of; properties; reliable; recognition; sequences; object

Comparing images under variable illumination - Jacobs, David W.; Belhumeur,P. N.; Basri,R. (Computer Vision and Pattern Recognition, 1998. Proceedings. 1998 IEEE Computer Society Conference on, 1998)
We consider the problem of determining whether two images come from different objects or the same object in the same pose, but under different illumination conditions. We show that this problem cannot be solved using hard constraints: even using a Lambertian reflectance model, there is always an object and a pair of lighting conditions consistent with any two images. Nevertheless, we show that for point sources and objects with Lambertian reflectance, the ratio of two images from the same object is simpler than the ratio of images from different objects. We also show that the ratio of the two images provides two of the three distinct values in the Hessian matrix of the object's surface. Using these observations, we develop a simple measure for matching images under variable illumination, comparing its performance to other existing methods on a database of 450 images of 10 individuals
Keywords: conditions; matching; illumination; visual; images; point; Lambertian; matching; object; model; database; lighting; object; recognition; recognition; image; reflectance; sources; pose; variable

Culture conflicts in software engineering technology transfer - Zelkowitz, Marvin V; Wallace,D. R; Binkley,D. (NASA Goddard Software Engineering Workshop, 1998)
Although the need to transition new technology to improve the process of developing quality software products is well understood, the computer software industry has done a poor job of carrying out that need. All too often new software technology is touted as the next "silver bullet" to be adopted, only to fail and disappear within a very short period. New technologies are often adopted without any convincing evidence that they will be effective, yet other technologies are ignored despite the published data that they will be useful. It is cClearly there is a clash between those developing new technologies and those responsible for developing quality products. In this paper we discuss a study conducted among a large group of computer software professionals in order to understand what techniques can be used to support the introduction of new technologies, and to understand the biases and opinions of those charged with researching, developing or implementing those new technologies. This study indicates which evaluation techniques are viewed as most successful under various conditions. We show that the research and industrial communities do indeed have different perspectives, which leads to a clash between the goals of the technology developers researchers and the needs of the technology users.

Designing to facilitate browsing: A look back at the Hyperties workstation browser - Shneiderman, Ben; Plaisant, Catherine; Botafogo,Rodrigo; Hopkins,Don; Weiland,William (Technical Reports of the Computer Science Department, University of Maryland, 1998)
Since browsing hypertext can present a formidable cognitivechallenge, user interface design plays a major role in determining acceptability. In the Unix workstation version of Hyperties, a research-oriented prototype, we focussed on design features that facilitate browsing. We first give a general overview of Hyperties and its markup language. Customizable documents can be generated by the conditional text feature that enables dynamic and selective display of text and graphics. In addition we present: - an innovative solution to link identification: pop-out graphical buttons of arbitrary shape. - application of pie menus to permit low cognitive load actions that reduce the distraction of common actions, such as page turning or window selection. - multiple window selection strategies that reduce clutter and housekeeping effort. We preferred piles-of-tiles, in which standard-sized windows were arranged in a consistent pattern on the display and actions could be done rapidly, allowing users to concentrate on the contents. (Also cross-referenced as CAR-TR-494)
Keywords: Technical Report

Determining the similarity of deformable shapes - Basri,Ronen; Costa,Luiz; Geiger,Davi; Jacobs, David W. (Vision Research, 1998)
Determining the similarity of two shapes is a significant task in both machine and human vision systems that must recognize or classify objects. The exact properties of human shape similarity judgements are not well understood yet, and this task is particularly difficult in domains where the shapes are not related by rigid transformations. In this paper we identify a number of possibly desirable properties of a shape similarity method, and determine the extent to which these properties can be captured by approaches that compare local properties of the contours of the shapes, through elastic matching. Special attention is devoted to objects that possess articulations, i.e. articulated parts. Elastic matching evaluates the similarity of two shapes as the sum of local deformations needed to change one shape into another. We show that similarities of part structure can be captured by such an approach, without the explicit computation of part structure. This may be of importance, since although parts appear to play a significant role in visual recognition, it is difficult to stably determine part structure. We also show novel results about how one can evaluate smooth and polyhedral shapes with the same method. Finally, we describe shape similarity effects that cannot be handled by current approaches.

Digital dynamic telepathology–the Virtual Microscope. - Afework,A.; Beynon,M. D; Bustamante,F.; Cho,S.; Demarzo,A.; Ferreira,R.; Miller,R.; Silberman,M.; Saltz, J.; Sussman, Alan; others (Proceedings of the AMIA Symposium, 1998)

Direction of Arrival and the Rank-Revealing URV Decomposition - Boman,E. C; Griffen,M. F; Stewart, G.W. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1998)
In many practical direction-of-arrival (DOA) problems the numberof sources and their directions from an antenna array do not remain stationary. Hence a practical DOA algorithm must be able to track changes with a minimal number of snapshots. In this paper we describe DOA algorithms, based on a new decomposition, that are not expensive to compute or difficult to update. The algorithms are compared with algorithms based on the singular value decomposition (SVD). (Also cross-referenced as UMIACS-TR-91-166)
Keywords: Technical Report

Directions of Motion Fields are Hardly Ever Ambiguous - Brodsky, Tomas; Fermüller, Cornelia; Aloimonos, J. (International Journal of Computer Vision, 1998)
If instead of the full motion field, we consider only the direction of the motion field due to a rigid motion, what can we say about the three-dimensional motion information contained in it? This paper provides a geometric analysis of this question based solely on the constraint that the depth of the surfaces in view is positive. The motivation behind this analysis is to provide a theoretical foundation for image constraints employing only the sign of flow in various directions and justify their utilization for addressing 3D dynamic vision problems.

EFFICIENT DETERMINATION OF SHAPE FROM MULTIPLE IMAGES CONTAINING PARTIAL INFORMATION - Basri,Ronen; GROVE,ADAM J.; Jacobs, David W. (Pattern Recognition, 1998)
We consider the problem of reconstructing the shape of a 2-D object from multiple partial images related by scaled translations, in the presence of occlusion. Lindenbaum and Bruckstein have considered this problem in the specific case of a translating object seen by small sensors, for application to the understanding of insect vision. Their solution is limited by the fact that its run time is exponential in the number of images and sensors. We generalize the problem to allow for arbitrary types of occlusion of objects that translate and change scale. We show that this more general version of the problem can be solved in time that is polynomial in the number of sensors, but that even the original problem posed by Lindenbaum and Bruckstein is, in fact, NP-hard when the number of images is unbounded. Finally, we consider the case where the object is known to be convex. We show that Lindenbaum and Bruckstein’s version of the problem is then efficiently solvable even when many images are used, as is the general problem in certain more restricted cases.
Keywords: 2-D shape recovery from multiple images; NP-complete; Shape recovery with occlusion

Emergent patterns of teaching/learning in electronic classrooms - Shneiderman, Ben; Borkowski,Ellen; Alavi,Maryam; Norman,Kent (Educational Technology Research and Development, 1998)
Novel patterns of teaching/learning have emerged from faculty and students who use our three teaching/learning theaters at the University of Maryland, College Park. These fully-equipped electronic classrooms have been used by 74 faculty in 264 semester-long courses since the fall of 1991 with largely enthusiastic reception by both faculty and students. The designers of the teaching/learning theaters sought to provide a technologically rich environment and a support staff so that faculty could concentrate on changing the traditional lecture from its unidirectional information flow to a more collaborative activity. As faculty have evolved their personal styles in using the electronic classrooms, novel patterns of teaching/learning have emerged. In addition to enhanced lectures, we identified three common patterns: (a) active individual learning, (b) small-group collaborative learning, and (c) entire-class collaborative learning.

An Empirical Study of Perspective-Based Usability Inspection - Zhang,Zhijun; Basili, Victor R.; Shneiderman, Ben (Proceedings of the Human Factors and Ergonomics Society Annual MeetingProceedings of the Human Factors and Ergonomics Society Annual Meeting, 1998)
Inspection is a fundamental means of achieving software usability. Past research showed that during usability inspection the success rate (percentage of problems detected) of each individual inspector was rather low. We developed perspective-based usability inspection, which divides the large variety of usability issues along different perspectives and focuses each inspection session on one perspective. We conducted a controlled experiment to study its effectiveness, using a post-test only control group experimental design, with 24 professionals as subjects. The control group used heuristic evaluation, which is the most popular technique for usability inspection. The experimental results are that 1) for usability problems covered by each perspective, the inspectors using that perspective had higher success rate than others; 2) for all usability problems, perspective inspectors had higher average success rate than heuristic inspectors; 3) for all usability problems, the union of three perspective inspectors (with one from each perspective) had higher average success rate than the union of three heuristic inspectors.

Explicit Multi-Threading (XMT) bridging models for instruction parallelism (extended abstract) - Vishkin, Uzi; Dascal,S.; Berkovich,E.; Nuzman,J. (Proceedings of the tenth annual ACM symposium on Parallel algorithms and architectures, 1998)

Extension of Spherical Harmonic Method to RF Transient Regime - Lin,C. K.; Goldsman,N.; Chang,C. H.; Mayergoyz, Issak D; Aronowitz,S.; Dong,J.; Belova,N. (Simulation of semiconductor processes and devices 1998: SISPAD 98, 1998)
The space and time dependent electron Boltzmann transport equation (BTE)is solved sclf-consistently with the Poisson and transient hole current-continuity equation. A transient Spherical Harmonic expansion method is used to solve the BTE. By this method we can efficiently solve the BTE in the RF regime to observe how the complete distribution function responds to a rapid transient. Calculations on a BJT, which give the time dependent distribution function over a large energy range 0-3eV, throughout the device, as well as average quantities, require only 40 minutes CPU time on an Alpha workstation.

Facility Location with Dynamic Distance Functions - Khuller, Samir; Sussmann,Y. J; Bhatia,Randeep; Guha,Sudipto (Journal of Combinatorial Optimization, 1998)
Facility location problems have always been studied with theassumption that the edge lengths in the network are static anddo not change over time. The underlying network could be used to model a city street networkfor emergency facility location/hospitals, or an electronic network for locating information centers. In any case, it is clear that due to trafficcongestion the traversal time on links changes with time. Very often, we have estimates as to how the edge lengths change over time, and our objective is to choose a set of locations (vertices) ascenters, such that at every time instant each vertex has a center close to it (clearly, the center close to a vertex may change over time). We also provide approximation algorithms as well as hardness results forthe K-center problem under this model. This is the first comprehensive study regarding approximation algorithmsfor facility location for good time-invariant solutions.

Feature-recognition for MEMS extraction - Baidya,B.; Gupta,S.K.; Mukherjee,T. (1998)

A framework for modeling appearance change in image sequences - Black,M. J; Fleet,D. J; Yacoob,Yaser (Computer Vision, 1998. Sixth International Conference on, 1998)
Image ldquo;appearance rdquo; may change over time due to a variety of causes such as: 1) object or camera motion; 2) generic photometric events including variations in illumination (e.g. shadows) and specular reflections; and 3) ldquo;iconic changes rdquo; which are specific to the objects being viewed and include complex occlusion events and changes in the material properties of the objects. We propose a general framework for representing and recovering these ldquo;appearance changes rdquo; in an image sequence as a ldquo;mixture rdquo; of different causes. The approach generalizes previous work on optical flow to provide a richer description of image events and more reliable estimates of image motion
Keywords: appearance change; camera motion; complex occlusion events; generic photometric events; iconic changes; illumination; image motion; Image sequences; Motion estimation; optical flow

Genetic nomenclature for Trypanosoma and Leishmania. - Clayton, C; Adams, M; Almeida, R; Baltz, T; Barrett, M; Bastien, P; Belli, S; Beverley, S; Biteau, N; Blackwell, J; Blaineau, C; Boshart, M; et al. (Mol Biochem Parasitol, 1998)
Keywords: Animals; Leishmania; Terminology as Topic; Trypanosoma

Genetic nomenclature for Trypanosoma and Leishmania. - Clayton,C.; Adams,M.; Almeida,R.; Baltz,T.; Barrett,M.; Bastien,P.; Belli,S.; Beverley,S.; Biteau,N.; Blackwell,J.; others (Molecular and biochemical parasitology, 1998)

Implementing a zooming User Interface: experience building Pad++ - Bederson, Benjamin B.; Meyer,Jon (Software: Practice and Experience, 1998)
We are investigating a novel user interface paradigm based on zooming, in which users are presented with a zooming view of a huge planar information surface. We have developed a system called Pad++ to explore this approach. The implementation of Pad++ is related to real-time 3D graphics systems and to 2D windowing systems. However, the zooming nature of Pad++ requires new approaches to rendering, screen management, and spatial indexing. In this paper, we describe the design and implementation of the Pad++ engine, focusing in particular on rendering and data structure issues. Our goal is to present useful techniques that can be adopted in other real-time graphical systems, and also to discuss how 2D zooming systems differ from other graphical systems. © 1998 John Wiley & Sons, Ltd.
Keywords: 3D graphics; animation; Pad++; real‐time computer graphics; User Interface Management Systems (UIMS); windowing systems; zooming User Interfaces (ZUIs)

An intelligent environment for simulating mechanical assembly operations - Gupta,S.K.; Paredis,C. J. J.; Sinha,R.; Wang,C. H.; Brown,P. F. (1998)
Rapid technical advances in many different areas of scientificcomputing provide the enabling technologies for creating a com- prehensive simulation and visualization environment for assembly design and planning. We have built an intelligent environment in which simple simulations can be composed together to create com- plex simulations for detecting potential assembly problems. Our goal in this project is to develop high fidelity assembly simulation and visualization tools that can detect assembly related problems without going through physical mock-ups. In addition, these tools can be used to create easy-to-visualize instructions for performing assembly and service operations.

Looking to Parallel Algorithms for ILP and Decentralization - Berkovich,Efraim; Jacob,Bruce; Nuzman,Joseph; Vishkin, Uzi (Department of Computer Science, University of Maryland, College Park, 1998)
We introduce explicit multi-threading (XMT), a decentralized architecturethat exploits fine-grained SPMD-style programming; a SPMD program can translate directly to MIPS assembly language using three additional instruction primitives. The motivation for XMT is: (i) to define an inherently decentralizable architecture, taking into account that the performance of future integrated circuits will be dominated by wire costs, (ii) to increase available instruction-level parallelism (ILP) by leveraging expertise in the world of parallel algorithms, and (iii) to reduce hardware complexity by alleviating the need to detect ILP at run-time: if parallel algorithms can give us an overabundance of work to do in the form of thread-level parallelism, one can extract instruction-level parallelism with greatly simplified dependence-checking. We show that implementations of such an architecture tend towards decentralization and that, when global communication is necessary, overall performance is relatively insensitive to large on-chip delays. We compare the performance of the design to more traditional parallel architectures and to a high-performance superscalar implementation, but the intent is merely to illustrate the performance behavior of the organization and to stimulate debate on the viability of introducing SPMD to the single-chip processor domain. We cannot offer at this stage hard comparisons with well-researched models of execution. When programming for the SPMD model, the total number of operations that the processor has to perform is often slightly higher. To counter this, we have observed that the length of the critical path through the dynamic execution graph is smaller than in the serial domain, and the amount of ILP is correspondingly larger. Fine-grained SPMD programming connects with a broad knowledge base in parallel algorithms and scales down to provide good performance relative to high-performance superscalar designs even with small input sizes and small numbers of functional units. Keywords: Fine-grained SPMD, parallel algorithms. spawn-join, prefix-sum, instruction-level parallelism, decentralized architecture. (Also cross-referenced as UMIACS-TR- 98-40)
Keywords: Technical Report

A new deterministic parallel sorting algorithm with an experimental evaluation - Helman,David R.; JaJa, Joseph F.; Bader,David A. (Journal of Experimental Algorithmics (JEA), 1998)
We introduce a new deterministic parallel sorting algorithm for distributed memory machines based on the regular sampling approach. The algorithm uses only two rounds of regular all-to-all personalized communication in a scheme that yields very good load balancing with virtually no overhead. Moreover, unlike previous variations, our algorithm efficiently handles the presence of duplicate values without the overhead of tagging each element with a unique identifier. This algorithm was implemented in SPLIT-C and run on a variety of platforms, including the Thinking Machines CM-5, the IBM SP-2-WN, and the Cray Research T3D. We ran our code using widely different benchmarks to examine the dependence of our algorithm on the input distribution. Our experimental results illustrate the efficiency and scalability of our algorithm across different platforms. In fact, the performance compares closely to that of our random sample sort algorithm, which seems to outperform all similar algorithms known to the authors on these platforms. Together, their performance is nearly invariant over the set of input distributions, unlike previous efficient algorithms. However, unlike our randomized sorting algorithm, the performance and memory requirements of our regular sorting algorithm can be deterministically guaranteed.
Keywords: generalized sorting; integer sorting; Parallel algorithms; parallel performance; sorting by regular sampling

Optimization of wrappers and mediators for web accessible data sources (websources) - Bright,L.; Raschid, Louiqa; Vidal,M. E (Workshop Web Inf. Data Management (WIDM), Washington DC, 1998)

Parallel Algorithms for Image Histogramming and Connected Components with an Experimental Study - Bader,David A.; JaJa, Joseph F. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1998)
This paper presents efficient and portable implementations of two useful primitives in image processing algorithms, histogramming and connected components. Our general framework is a single-address space, distributed memory programming model. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. Our connected components algorithm uses a novel approach for parallel merging which performs drastically limited updating during iterative steps, and concludes with a total consistency update at the final step. The algorithms have been coded in Split-C and run on a variety of platforms. Our experimental results are consistent with the theoretical analysis and provide the best known execution times for these two primitives, even when compared with machine specific implementations. More efficient implementations of Split-C will likely result in even faster execution times. (Also cross-referenced as UMIACS-TR-94-133.)
Keywords: Technical Report

A Parallel Sorting Algorithm With an Experimental Study - Helman,David R.; Bader,David A.; JaJa, Joseph F. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1998)
Previous schemes for sorting on general-purpose parallel machineshave had to choose between poor load balancing and irregular communication or multiple rounds of all-to-all personalized communication. In this paper, we introduce a novel variation on sample sort which uses only two rounds of regular all-to-all personalized communication in a scheme that yields very good load balancing with virtually no overhead. This algorithm was implemented in Split-C and run on a variety of platforms, including the Thinking Machines CM-5, the IBM SP-2, and the Cray Research T3D. We ran our code using widely different benchmarks to examine the dependence of our algorithm on the input distribution. Our experimental results are consistent with the theoretical analysis and illustrate the efficiency and scalability of our algorithm across different platforms. In fact, it seems to outperform all similar algorithms known to the authors on these platforms, and its performance is invariant over the set of input distributions unlike previous efficient algorithms. Our results also compare favorably with those reported for the simpler ranking problem posed by the NAS Integer Sorting (IS) Benchmark. (Also cross-referenced as UMIACS-TR-95-102)
Keywords: Technical Report

Parameterized modeling and recognition of activities - Yacoob,Yaser; Black,M. J (Computer Vision, 1998. Sixth International Conference on, 1998)
A framework for modeling and recognition of temporal activities is proposed. The modeling of sets of exemplar activities is achieved by parameterizing their representation in the form of principal components. Recognition of spatio-temporal variants of modeled activities is achieved by parameterizing the search in the space of admissible transformations that the activities can undergo. Experiments on recognition of articulated and deformable object motion from image motion parameters are presented
Keywords: activities recognition; admissible transformations; articulated object motion; deformable object motion; exemplar activities; image motion parameters; Image sequences; Motion estimation; parameterized modeling; recognition; spatio-temporal variants

A Randomized Parallel Sorting Algorithm with an Experimental Study - Helman,David R.; Bader,David A.; JaJa, Joseph F. (Journal of Parallel and Distributed Computing, 1998)
Previous schemes for sorting on general-purpose parallel machines have had to choose between poor load balancing and irregular communication or multiple rounds of all-to-all personalized communication. In this paper, we introduce a novel variation on sample sort which uses only two rounds of regular all-to-all personalized communication in a scheme that yields very good load balancing with virtually no overhead. Moreover, unlike previous variations, our algorithm efficiently handles the presence of duplicate values without the overhead of tagging each element with a unique identifier. This algorithm was implemented in Split-C and run on a variety of platforms, including the Thinking Machines CM-5, the IBM SP-2, and the Cray Research T3D. We ran our code using widely different benchmarks to examine the dependence of our algorithm on the input distribution. Our experimental results illustrate the efficiency and scalability of our algorithm across different platforms. In fact, it seems to outperform all similar algorithms known to the authors on these platforms, and its performance is invariant over the set of input distributions unlike previous efficient algorithms. Our results also compare favorably with those reported for the simpler ranking problem posed by the NAS Integer Sorting (IS) Benchmark.
Keywords: generalized sorting; integer sorting, sample sort, parallel performance; Parallel algorithms

Scalable Data Parallel Algorithms for Texture Synthesis and Compression using Gibbs Random Fields - Bader,David A.; JaJa, Joseph F.; Chellapa, Rama (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1998)
This paper introduces scalable data parallel algorithms for image processing. Focusing on Gibbs and Markov Random Field model representation for textures, we present parallel algorithms for texture synthesis, compression, and maximum likelihood parameter estimation, currently implemented on Thinking Machines CM-2 and CM-5. Use of fine-grained, data parallel processing techniques yields real-time algorithms for texture synthesis and compression that are substantially faster than the previously known sequential implementations. Although current implementations are on Connection Machines, the methodology presented here enables machine independent scalable algorithms for a number of problems in image processing and analysis. (Also cross-referenced as UMIACS-TR-93-80.)
Keywords: Technical Report

Self-calibration from image derivatives - Brodsky, T.; Fermüller, Cornelia; Aloimonos, J. (Sixth International Conference on Computer Vision, 1998, 1998)
This study investigates the problem of estimating the calibration parameters from image motion fields induced by a rigidly moving camera with unknown calibration parameters, where the image formation is modeled with a linear pinhole-camera model. The equations obtained show the flow to be clearly separated into a component due to the translation and the calibration parameters and a component due to the rotation and the calibration parameters. A set of parameters encoding the latter component are linearly related to the flow, and from these parameters the calibration can be determined. However, as for discrete motion, in the general case it is not possible, to decouple image measurements from two frames only into their translational and rotational component. Geometrically, the ambiguity takes the form of a part of the rotational component being parallel to the translational component, and thus the scene can be reconstructed only up to a projective transformation. In general, for a full calibration at least four successive image frames are necessary with the 3D-rotation changing between the measurements. The geometric analysis gives rise to a direct self-calibration method that avoids computation of optical flow or point correspondences and uses only normal flow measurements. In this technique the direction of translation is estimated employing in a novel way smoothness constraints. Then the calibration parameters are estimated from the rotational components of several flow fields using Levenberg-Marquardt parameter estimation, iterative in the calibration parameters only. The technique proposed does not require calibration objects in the scene or special camera motions and it also avoids the computation of exact correspondence. This makes it suitable for the calibration of active vision systems which have to acquire knowledge about their intrinsic parameters while they perform other tasks, or as a tool for analyzing image sequences in large video databases
Keywords: 3D-rotation; active vision; Calibration; CAMERAS; discrete motion; Encoding; Equations; image derivatives; image formation; image measurements; Image motion analysis; image motion fields; Image reconstruction; Image sequences; large video databases; Layout; Levenberg-Marquardt parameter estimation; linear pinhole-camera model; Motion estimation; Motion measurement; Optical computing; parameter estimation; projective transformation; rigidly moving camera; self-calibration; smoothness constraints; unknown calibration parameters

Shape from video: Beyond the epipolar constraint - Brodsky, T.; Fermüller, Cornelia; Aloimonos, J. (Proceedings of the DARPA Image Understanding Workshop, 1998)

Simultaneous estimation of viewing geometry and structure - Brodský,Tomáš; Fermüller, Cornelia; Aloimonos, J. (Computer Vision — ECCV'98Computer Vision — ECCV'98, 1998)
Up to now, structure from motion algorithms proceeded in two well defined steps, where the first and most important step is recovering the rigid transformation between two views, and the subsequent step is using this transformation to compute the structure of the scene in view. This paper introduces a novel approach to structure from motion in which both aforementioned steps are accomplished in a synergistic manner. Existing approaches to 3D motion estimation are mostly based on the use of optic flow which however poses a problem at the locations of depth discontinuities. If we knew where depth discontinuities were, we could (using a multitude of approaches based on smoothness constraints) estimate accurately flow values for image patches corresponding to smooth scene patches; but to know the discontinuities requires solving the structure from motion problem first. In the past this dilemma has been addressed by improving the estimation of flow through sophisticated optimization techniques, whose performance often depends on the scene in view. In this paper we follow a different approach. The main idea is based on the interaction between 3D motion and shape which allows us to estimate the 3D motion while at the same time segmenting the scene. If we use a wrong 3D motion estimate to compute depth, then we obtain a distorted version of the depth function. The distortion, however, is such that the worse the motion estimate, the more likely we are to obtain depth estimates that are locally unsmooth, i.e., they vary more than the correct ones. Since local variability of depth is due either to the existence of a discontinuity or to a wrong 3D motion estimate, being able to differentiate between these two cases provides the correct motion, which yields the “smoothest” estimated depth as well as the image location of scene discontinuities. Although no optic flow values are computed, we show that our algorithm is very much related to minimizing the epipolar constraint and we present a number of experimental results with real image sequences indicating the robustness of the method.

Sorting out searching: a user-interface framework for text searches - Shneiderman, Ben; Byrd,Donald; Croft,W. Bruce (Communications of the ACM, 1998)

SRRIT--A FORTRAN Subroutine to Calculate the Dominant Invariant Subspace of a Nonsymmetric Matrix - Bai,Z.; Stewart, G.W. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1998)
SRRIT is a FORTRAN program to calculate an approximateorthonormal basis for a dominant invariant subspace of a real matrix $A$ by the method of simultaneous iteration \cite{stewart76a}. Specifically, given an integer $m$, {\sl SRRIT} attempts to compute a matrix $Q$ with $m$ orthonormal columns and real quasi-triangular matrix $T$ of order $m$ such that the equation \[ AQ = QT \] is satisfied up to a tolerance specified by the user. The eigenvalues of $T$ are approximations to the $m$ largest eigenvalues of $A$, and the columns of $Q$ span the invariant subspace corresponding to those eigenvalues. {\sl SRRIT} references $A$ only through a user provided subroutine to form the product $AQ$; hence it is suitable for large sparse problems. (Also cross-referenced as UMIACS-TR-92-61)
Keywords: Technical Report

A Survey of Current Paradigms in Machine Translation - Dorr, Bonnie J; Jordan,P.W.; Benoit,J.W. (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 1998)
This is paper is a survey of the current machine translation research in the US, Eu-rope, and Japan. A short history of machine translation is presented first, followed by an overview of the current research work. Representative examples of a wide range of different approaches adopted by machine translation researchers are presented. These are described in detail along with a discussion of the practicalities of scaling up these approaches for operational environments. In support of this discussion, issues in, and techniques for, evaluating machine translation systems are discussed.

Trends in the Early Careers of Life Scientists - Tilghman,S; Astin,HS; Brinkley,W; Chilton,MD; Cummings, Michael P.; Ehrenberg,RG; Fox,MF; Glenn,K; Green,PJ; Hans,S; Kelman,A; LaPidus,J; et al. (National Academy Press, 1998)

Trends in the early careers of life scientists - Preface and executive summary - Tilghman,S; Astin,HS; Brinkley,W; Chilton,MD; Cummings, Michael P.; Ehrenberg,RG; Fox,MF; Glenn,K; Green,PJ; Hans,S; Kelman,A; LaPidus,J; et al. (Mol Biol Cell, 1998)

The Video Yardstick - Brodský,Tomáš; Fermüller, Cornelia; Aloimonos, J. (Modelling and Motion Capture Techniques for Virtual EnvironmentsModelling and Motion Capture Techniques for Virtual Environments, 1998)
Given uncalibrated video sequences, how can we recover rich descriptions of the scene content, beyond two-dimensional (2D) measurements such as color/texture or motion fields — descriptions of shape and three-dimensional (3D) motion? This is the well known structure from motion (SFM) problem. Up to now, SFM algorithms proceeded in two well defined steps, where the first and most important step is recovering the rigid transformation between two views, and the subsequent step is using this transformation to compute the structure of the scene in view. This paper introduces a novel approach to structure from motion in which both steps are accomplished in a synergistic manner. It deals with the classical structure from motion problem considering a calibrated camera as well as the extension to an uncalibrated optical device. Existing approaches to estimation of the viewing geometry are mostly based on the use of optic flow, which, however, poses a problem at the locations of depth discontinuities. If we knew where depth discontinuities were, we could (using a multitude of approaches based on smoothness constraints) accurately estimate flow values for image patches corresponding to smooth scene patches; but to know the discontinuities requires solving the structure from motion problem first. In the past this dilemma has been addressed by improving the estimation of flow through sophisticated optimization techniques, whose performance often depends on the scene in view. In this paper we follow a different approach. We directly utilize the image derivatives and employ constraints which involve the 3D motion and shape of the scene, leading to a geometric and statistical estimation problem. The main idea is based on the interaction between 3D motion and shape which allows us to estimate the 3D motion while at the same time segmenting the scene. If we use a wrong 3D motion estimate to compute depth, we obtain a distorted version of the depth function. The distortion, however, is such that the worse the motion estimate, the more likely we are to obtain depth estimates that are locally unsmooth, i.e., they vary more than the correct ones. Since local variability of depth is due either to the existence of a discontinuity or to a wrong 3D motion estimate, being able to differentiate between these two cases provides the correct motion, which yields the “smoothest” estimated depth as well as the image locations of scene discontinuities. We analyze the new constraints introduced by our approach and show their relationship to the minimization of the epipolar constraint, which becomes a special case of our theory. Finally, we present a number of experimental results with real image sequences indicating the robustness of our method and the improvement over traditional methods. The resulting system is a video yardstick that can be applied to any video sequence to recover first the calibration parameters of the camera that captured the video and, subsequently, the structure of the scene.

Is the Web really different from everything else? - Shneiderman, Ben; Nielsen,Jakob; Butler,Scott; Levi,Michael; Conrad,Frederick (CHI 98 conference summary on Human factors in computing systems, 1998)
Keywords: design; user experience; World Wide Web

What is computed by structure from motion algorithms? - Fermüller, Cornelia; Aloimonos, J. (Computer Vision — ECCV'98, 1998)
In the literature we find two classes of algorithms which, on the basis of two views of a scene, recover the rigid transformation between the views and subsequently the structure of the scene. The first class contains techniques which require knowledge of the correspondence or the motion field between the images and are based on the epipolar constraint. The second class contains so-called direct algorithms which require knowledge about the value of the flow in one direction only and are based on the positive depth constraint. Algorithms in the first class achieve the solution by minimizing a function representing deviation from the epipolar constraint while direct algorithms find the 3D motion that, when used to estimate depth, produces a minimum number of negative depth values. This paper presents a stability analysis of both classes of algorithms. The formulation is such that it allows comparison of the robustness of algorithms in the two classes as well as within each class. Specifically, a general statistical model is employed to express the functions which measure the deviation from the epipolar constraint and the number of negative depth values, and these functions are studied with regard to their topographic structure, specifically as regards the errors in the 3D motion parameters at the places representing the minima of the functions. The analysis shows that for algorithms in both classes which estimate all motion parameters simultaneously, the obtained solution has an error such that the projections of the translational and rotational errors on the image plane are perpendicular to each other. Furthermore, the estimated projection of the translation on the image lies on a line through the origin and the projection of the real translation.

When Two Hands Are Better Than One: Enhancing Collaboration Using Single Display Groupware. CHI’98 - Stewart,J.; Raybourn,E.; Bederson, Benjamin B.; Druin, Allison (Extended Abstracts, 1998)

Wrapper generation for Web accessible data sources - Gruser,J.; Raschid, Louiqa; Vidal,M. E; Bright,L. (3rd IFCIS International Conference on Cooperative Information Systems, 1998. Proceedings, 1998)
There is an increase in the number of data sources that can be queried across the WWW. Such sources typically support HTML forms-based interfaces and search engines query collections of suitably indexed data. The data is displayed via a browser: One drawback to these sources is that there is no standard programming interface suitable for applications to submit queries. Second, the output (answer to a query) is not well structured. Structured objects have to be extracted from the HTML documents which contain irrelevant data and which may be volatile. Third, domain knowledge about the data source is also embedded in HTML documents and must be extracted. To solve these problems, we present technology to define and (automatically) generate wrappers for Web accessible sources. Our contributions are as follows: (1) Defining a wrapper interface to specify the capability of Web accessible data sources. (2) Developing a wrapper generation toolkit of graphical interfaces and specification languages to specify the capability of sources and the functionality of the wrapper (3) Developing the technology to automatically generate a wrapper appropriate to the Web accessible source, from the specifications.
Keywords: application program interfaces; data mining; Databases; Educational institutions; Electrical capacitance tomography; HTML; HTML documents; Internet; Query processing; Read only memory; Search engines; Specification languages; Uniform resource locators; World Wide Web; wrapper generation toolkit; WWW

3-D to 2-D recognition with regions - Jacobs, David W.; Basri,R. (Computer Vision and Pattern Recognition, 1997. Proceedings., 1997 IEEE Computer Society Conference on, 1997)
This paper presents a novel approach to parts-based object recognition in the presence of occlusion. We focus on the problem of determining the pose of a 3-D object from a single 2-D image when convex parts of the object have been matched to corresponding regions in the image. We consider three types of occlusions: self-occlusion, occlusions whose locus is identified in the image, and completely arbitrary occlusions. We derive efficient algorithms for the first two cases, and characterize their performance. For the last case, we prove that the problem of finding valid poses is computationally hard, but provide an efficient, approximate algorithm. This work generalizes our previous work on region-based object recognition, which focused on the case of planar models
Keywords: 2-D; algorithms; object; complexity; image; hard; efficient; image; 3-D; object; computationally; poses; computational; recognition; recognition; occlusion; occlusions; performance; regions; valid; segmentation; object

Algorithm 776: SRRIT: a Fortran subroutine to calculate the dominant invariant subspace of a nonsymmetric matrix - Bai,Z.; Stewart, G.W. (ACM Trans. Math. Softw., 1997)
SRRT is a Fortran program to calculate an approximate orthonomral basis fr a dominant invariant subspace of a real matrix A by the method of simultaneous iteration. Specifically, given an integer m, SRRIT computes a matrix Q with m orthonormal columns and real quasi-triangular matrix T or order m such that the equation AQ = QT is satisfied up to a tolerance specified by the user. The eigenvalues of T are approximations to the m eigenvalues of largest absolute magnitude of A and the columns of Q span the invariant subspace corresponding to those eigenvalues. SRRIT references A only through a user-provided subroutine to form the product AQ; hence it is suitable for large sparse problems.
Keywords: invariant subspace; nonsymmetric eigenvalue problem; project method

APGAN and RPMC: Complementary heuristics for translating DSP block diagrams into efficient software implementations - Bhattacharyya, Shuvra S.; Murthy,P. K; Lee,E. A (Design Automation for Embedded Systems, 1997)

Bringing treasures to the surface: iterative design for the Library of Congress National Digital Library Program - Plaisant, Catherine; Marchionini,Gary; Bruns,Tom; Komlodi,Anita; Campbell,Laura (Proceedings of the SIGCHI conference on Human factors in computing systems, 1997)
Keywords: browse; design process; digital libraries; dynamic query; java; preview; search; web design

Clarifying search: A user-interface framework for text searches - Shneiderman, Ben; Byrd,D.; Croft, W.B. (D-lib magazine, 1997)
Current user interfaces for textual database searching leave much to be desired: individually, they are often confusing, and as a group, they are seriously inconsistent. We propose a four- phase framework for user-interface design: the framework provides common structure and terminology for searching while preserving the distinct features of individual collections and search mechanisms. Users will benefit from faster learning, increased comprehension, and better control, leading to more effective searches and higher satisfaction.

Comments on "Towards a framework for software measurement validation" - Morasca,S.; Briand,L.C.; Basili, Victor R.; Weyuker,E.J.; Zelkowitz, Marvin V; Kitchenham,B.; Lawrence Pfleeger,S.; Fenton,N. (Software Engineering, IEEE Transactions on, 1997)
A view of software measurement that disagrees with the model presented by Kitchenham, Pfleeger, and Fenton (1995), is given. Whereas Kitchenham et al. argue that properties used to define measures should not constrain the scale type of measures, the authors contend that that is an inappropriate restriction. In addition, a misinterpretation of Weyuker's (1988) properties is noted.
Keywords: measurement; metrics; software; testing; program; validation; program; verification; software

Computer models: A new approach to the investigation of disease - Reggia, James A.; Ruppin,E.; Berndt,R. S (MD Computing, 1997)

Constancy and similarity - Basri,R.; Jacobs, David W. (Computer Vision and Image Understanding, 1997)

Design and evaluation of incremental data structures and algorithms for dynamic query interfaces - Tanin,E.; Beigel,R.; Shneiderman, Ben (IEEE Symposium on Information Visualization, 1997. Proceedings, 1997)
A dynamic query interface (DQI) is a database access mechanism that provides continuous real-time feedback to the user during query formulation. Previous work shows that DQIs are elegant and powerful interfaces to small databases. Unfortunately, when applied to large databases, previous DQI algorithms slow to a crawl. We present a new incremental approach to DQI algorithms and display updates that work well with large databases, both in theory and in practice.
Keywords: Algorithm design and analysis; Bars; Computer science; continuous real-time feedback; Data structures; data visualisation; Data visualization; database access mechanism; Displays; DQI algorithms; dynamic query interfaces; Feedback; Graphical user interfaces; Heuristic algorithms; incremental data structures; Information Visualization; large databases; Manipulator dynamics; NASA; query formulation; query languages; Query processing; real-time systems; small databases; User interfaces; very large databases; visual databases; visual languages

The distributed information search component (disco) and the world wide web - Naacke,H.; Kapitskaia,O.; Tomasic,A.; Bonnet,P.; Raschid, Louiqa; Amouroux,R. (Proc. of ACM SIGMOD Conf. on Management of Data, 1997)

Dynamic priorities for modeling real-time - Bhat,G.; Cleaveland, Rance; L\üttgen,G. (Proc. of the Formal Description Techniques and Protocol Specification, Testing and Verification (FORTE X/PSTV XVII’97), 1997)

Editorial: Evaluation and assessment in software engineering - Kitchenham,B.; Brereton,P.; Budgen,D.; Linkman,S.; Almstrum,V. L; Pfleeger,S. L; Zelkowitz, Marvin V; Wallace,D. (Information and Software Technology, 1997)

If your version control system could talk - Ball,T.; Kim,J. M; Porter, Adam; Siy,H. P (ICSE Workshop on Process Modelling and Empirical Studies of Software Engineering, 1997)

Joint minimization of code and data for synchronous dataflow programs - Murthy,P. K; Bhattacharyya, Shuvra S.; Lee,E. A (Formal Methods in System Design, 1997)

KidPad: a design collaboration between children, technologists, and educators - Druin, Allison; Stewart,J.; Proft,D.; Bederson, Benjamin B.; Hollan,J. (Proceedings of the SIGCHI conference on Human factors in computing systems, 1997)

Learning parameterized models of image motion - Black,M. J; Yacoob,Yaser; Jepson,A. D; Fleet,D. J (Computer Vision and Pattern Recognition, 1997. Proceedings., 1997 IEEE Computer Society Conference on, 1997)
A framework for learning parameterized models of optical flow from image sequences is presented. A class of motions is represented by a set of orthogonal basis flow fields that are computed from a training set using principal component analysis. Many complex image motions can be represented by a linear combination of a small number of these basis flows. The learned motion models may be used for optical flow estimation and for model-based recognition. For optical flow estimation we describe a robust, multi-resolution scheme for directly computing the parameters of the learned flow models from image derivatives. As examples we consider learning motion discontinuities, non-rigid motion of human mouths, and articulated human motion
Keywords: image motion; Image sequences; learning; learning (artificial intelligence); model-based recognition; Motion estimation; multi-resolution scheme; non-rigid motion; optical flow; optical flow estimation; parameterized models; Principal component analysis; training set

Local Rules for Protein Folding on a Triangular Lattice and Generalized Hydrophobicity in the HP Model - Agarwala,Richa; Batzoglou,Serafim; DančíK,Vlado; Decatur,Scott E.; Hannenhalli, Sridhar; Farach,Martin; Muthukrishnan,S.; Skiena,Steven (Journal of Computational Biology, 1997)
We consider the problem of determining the three-dimensional folding of a protein given its one-dimensional amino acid sequence. We use the HP model for protein folding proposed by Dill (1985), which models protein as a chain of amino acid residues that are either hydrophobic or polar, and hydrophobic interactions are the dominant initial driving force for the protein folding. Hart and Istrail (1996a) gave approximation algorithms for folding proteins on the cubic lattice under the HP model. In this paper, we examine the choice of a lattice by considering its algorithmic and geometric implications and argue that the triangular lattice is a more reasonable choice. We present a set of folding rules for a triangular lattice and analyze the approximation ratio they achieve. In addition, we introduce a generalization of the HP model to account for residues having different levels of hydrophobicity. After describing the biological foundation for this generalization, we show that in the new model we are able to achieve similar constant factor approximation guarantees on the triangular lattice as were achieved in the standard HP model. While the structures derived from our folding rules are probably still far from biological reality, we hope that having a set of folding rules with different properties will yield more interesting folds when combined.

A note on conjugate gradient convergence - Naiman, A. E; Babuška, I. M; Elman, Howard (Numerische Mathematik, 1997)

Optimized software synthesis for synchronous dataflow - Bhattacharyya, Shuvra S.; America,H. (Proceedings of the ASAP97, 1997)

Optimizing synchronization in multiprocessor DSP systems - Bhattacharyya, Shuvra S.; Sriram,S.; Lee,E. A (Signal Processing, IEEE Transactions on, 1997)

Query previews for networked information systems: a case study with NASA environmental data - Doan,K.; Plaisant, Catherine; Shneiderman, Ben; Bruns,T. (SIGMOD Record, 1997)
Formulating queries on networked information systemsis laden with problems: data diversity, data complexity, network growth, varied user base, and slow network access. This paper proposes a new approach to a network query user interface which consists of two phases: query preview and query refinement. This new approach is based on dynamic queries and tight coupling, guiding users to rapidly and dynamically eliminate undesired items, reduce the data volume to a manageable size, and refine queries locally before submission over a network. A two-phase dynamic query system for NASA’s Earth Observing Systems--Data Information Systems (EOSDIS) is presented. The prototype was well received by the team of scientists who evaluated the interface.

Query previews in networked information systems: the case of EOSDIS - Plaisant, Catherine; Bruns,Tom; Shneiderman, Ben; Doan,Khoa (CHI '97 extended abstracts on Human factors in computing systems: looking to the future, 1997)
Dynamic queries have been shown to be an effective technique to browse information, and to find patterns and exceptions. Dynamic queries involve the interactive control by a user of visual query parameters that generate rapid (100 ms update), animated, and visual displays of database search results. The data of early implementations was stored in local memory to guarantee optimal speed. Problems arise when the data is very large and distributed over a network. To overcome the problems of slow networks and data volume we propose a two-phase approach to query formulation using query previews and query refinements [1]. Preview mechanisms have been used in the past [2] and we believe that their use will be a major component of successful networked information systems interfaces (e.g. [3]).
Keywords: direct manipulation; dynamic query; earth science; network information system; query preview; Visualization

Recognition using region correspondences - Basri,R.; Jacobs, David W. (International Journal of Computer Vision, 1997)
Recognition systems attempt to recover information about the identity of observed objects and their location in the environment. A fundamental problem in recognition is pose estimation. This is the problem of using a correspondence between some portions of an object model and some portions of an image to determine whether the image contains an instance of the object, and, in case it does, to determine the transformation that relates the model to the image. The current approaches to this problem are divided into methods that use ldquoglobalrdquo properties of the object (e.g., centroid and moments of inertia) and methods that use ldquolocalrdquo properties of the object (e.g., corners and line segments). Global properties are sensitive to occlusion and, specifically, to self occlusion. Local properties are difficult to locate reliably, and their matching involves intensive computation.We present a novel method for recognition that uses region information. In our approach the model and the image are divided into regions. Given a match between subsets of regions (without any explicit correspondence between different pieces of the regions) the alignment transformation is computed. The method applies to planar objects under similarity, affine, and projective transformations and to projections of 3-D objects undergoing affine and projective transformations. The new approach combines many of the advantages of the previous two approaches, while avoiding some of their pitfalls. Like the global methods, our approach makes use of region information that reflects the true shape of the object. But like local methods, our approach can handle occlusion.

Symbolic model checking of infinite state systems using Presburger arithmetic - Bultan,T.; Gerber,R.; Pugh, William (Computer Aided Verification, 1997)