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Faculty Publications

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Articles 241 - 270 of 321

Full-Text Articles in Computer Engineering

Feature Selection For Real-Time Tracking, D. Frank Hsu, Damian M. Lyons, Jizhou Ai Apr 2006

Feature Selection For Real-Time Tracking, D. Frank Hsu, Damian M. Lyons, Jizhou Ai

Faculty Publications

We address the problem of selecting features to improve automated video tracking of targets that undergo multiple mutual occlusions. As targets are occluded, different feature subsets and combinations of those features are effective in identifying the target and improving tracking performance. We use Combinatorial Fusion Analysis to develop a metric to dynamically select which subset of features will produce the most accurate tracking. In particular we show that the combination of a pair of features A and B will improve the accuracy only if (a) A and B have relative high performance, and (b) A and B are diverse. We …

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Jamming Sensor Networks: Attack And Defense Strategies, Wenyuan Xu, Wade Trappe, Yanyong Zhang Apr 2006

Jamming Sensor Networks: Attack And Defense Strategies, Wenyuan Xu, Wade Trappe, Yanyong Zhang

Faculty Publications

Wireless sensor networks are built upon a shared medium that makes it easy for adversaries to conduct radio interference, or jamming, attacks that effectively cause a denial of service of either transmission or reception functionalities. These attacks can easily be accomplished by an adversary by either bypassing MAC-layer protocols or emitting a radio signal targeted at jamming a particular channel. In this article we survey different jamming attacks that may be employed against a sensor network. In order to cope with the problem of jamming, we discuss a two-phase strategy involving the diagnosis of the attack, followed by a suitable …

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A Reconfigurable Distributed Computing Fabric Exploiting Multilevel Parallelism, Charles L. Cathey, Jason D. Bakos, Duncan A. Buell Apr 2006

A Reconfigurable Distributed Computing Fabric Exploiting Multilevel Parallelism, Charles L. Cathey, Jason D. Bakos, Duncan A. Buell

Faculty Publications

This paper presents a novel reconfigurable data flow processing architecture that promises high performance by explicitly targeting both fine- and course-grained parallelism. This architecture is based on multiple FPGAs organized in a scalable direct network that is substantially more interconnect-efficient than currently used crossbar technology. In addition, we discuss several ancillary issues and propose solutions required to support this architecture and achieve maximal performance for general-purpose applications; these include supporting IP, mapping techniques, and routing policies that enable greater flexibility for architectural evolution and code portability.

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Convergence Of Ipsec In Presence Of Resets, Chin-Tser Huang, Mohamed G. Gouda, E.N. Elnozahy Mar 2006

Convergence Of Ipsec In Presence Of Resets, Chin-Tser Huang, Mohamed G. Gouda, E.N. Elnozahy

Faculty Publications

IPsec is the current security standard for the Internet Protocol IP. According to this standard, a selected computer pair (p, q) in the Internet can be designated a “security association”. This designation guarantees that all sent IP messages whose original source is computer p and whose ultimate destination is computer q cannot be replayed in the future (by an adversary between p and q) and still be received by computer q as fresh messages from p. This guarantee is provided by adding increasing sequence numbers to all IP messages sent from p to q. Thus, p needs to always remember …

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Adaptive Evolution Of Chloroplast Genome Structure Inferred Using A Parametric Bootstrap Approach, Liying Cui, Jim Leebens-Mack, Li-San Wang, Jijun Tang, Linda Rymarquis, David B. Stern, Claude W. Depamphilis Feb 2006

Adaptive Evolution Of Chloroplast Genome Structure Inferred Using A Parametric Bootstrap Approach, Liying Cui, Jim Leebens-Mack, Li-San Wang, Jijun Tang, Linda Rymarquis, David B. Stern, Claude W. Depamphilis

Faculty Publications

Background
Genome rearrangements influence gene order and configuration of gene clusters in all genomes. Most land plant chloroplast DNAs (cpDNAs) share a highly conserved gene content and with notable exceptions, a largely co-linear gene order. Conserved gene orders may reflect a slow intrinsic rate of neutral chromosomal rearrangements, or selective constraint. It is unknown to what extent observed changes in gene order are random or adaptive. We investigate the influence of natural selection on gene order in association with increased rate of chromosomal rearrangement. We use a novel parametric bootstrap approach to test if directional selection is responsible for the …

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Concurrent Multiple- Issue Negotiation For Internet-Based Services, Jiangbo Dang, Michael N. Huhns Jan 2006

Concurrent Multiple- Issue Negotiation For Internet-Based Services, Jiangbo Dang, Michael N. Huhns

Faculty Publications

Negotiation is a technique for reaching a mutually beneficial agreement among autonomous entities. In an Internet-based services context, multiple entities are negotiating simultaneously. The concurrent negotiation protocol extends existing negotiation protocols, letting both service requestors and service providers manage several negotiation processes in parallel. Colored Petri nets, which have greater expressive power than finite state machines and offer support for concurrency, represent the negotiation protocol and facilitate the analysis of desirable properties.

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Loss Aware Rate Allocations In H.263 Coded Video Transmissions, Xiao Su, Benjamin Wah Dec 2005

Loss Aware Rate Allocations In H.263 Coded Video Transmissions, Xiao Su, Benjamin Wah

Faculty Publications

For packet video, information loss and bandwidth limitation are two factors that affect video playback quality. Traditional rate allocation approaches have focused on optimizing video quality under bandwidth constraint alone. However, in the best-effort Internet, packets carrying video data are susceptible to losses, which need to be reconstructed at the receiver side. In this paper, we propose loss aware rate allocations in both group-of-block (GOB) level and macroblock level, given that certain packets are lost during transmissions and reconstructed using simple interpolation methods at the receiver side. Experimental results show that our proposed algorithms can produce videos of higher quality …

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Analysis Of Gaits For A Rotating Tripedal Robot, Damian M. Lyons, Kiran Pamnany Oct 2005

Analysis Of Gaits For A Rotating Tripedal Robot, Damian M. Lyons, Kiran Pamnany

Faculty Publications

A goal of robotics has been to develop mechanisms that have the efficiency and speed of wheeled robots with the terrain flexibility of legged robots. In previous work, we have proposed a unique three-legged mechanism, the rotopod, designed to integrate these two useful approaches to locomotion. In this paper, we present an analysis of the variety of gaits that can be exhibited by the rotopod. We present examples of many of these gaits and discuss their potential use. A trajectory generation algorithm is presented that can be used to generate point to point trajectories using one of three different styles …

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Ontologies In Web Personalization, Magdalini Eirinaki, Michalis Vazirgiannis Oct 2005

Ontologies In Web Personalization, Magdalini Eirinaki, Michalis Vazirgiannis

Faculty Publications

No abstract provided.

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Optimizing Transmission Time Of Scalable Coded Images In Peer-To-Peer Networks, Xiao Su, Rod Fatoohi, Tao Wang Aug 2005

Optimizing Transmission Time Of Scalable Coded Images In Peer-To-Peer Networks, Xiao Su, Rod Fatoohi, Tao Wang

Faculty Publications

In this paper, we study how to optimize image transmission time in peer-to-peer networks by considering the property of bitstreams generated by image coding algorithms. Images can be either scalable coded or nonscalable coded. Since transmission of nonscalable coded images is well understood, we focus on the transmission of scalable coded images in this paper.Because scalable coding embeds lower bit-rate bitstreams into higher bit-rate bitstreams, there exists a many-to-one relationship between supplying and requesting peers. When a requesting peer asks for an image coded in a particular bit rate, multiple peers with the same image but coded in different bit …

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Rotational Legged Locomotion, Damian M. Lyons, Kiran Pamnany Jul 2005

Rotational Legged Locomotion, Damian M. Lyons, Kiran Pamnany

Faculty Publications

In this paper we presented a novel, agile robot mechanism, which we call a rotopod, which combines aspects of wheeled and legged locomotion. A general description of how a tripedal rotopod can be made to step, rotating the mechanism about one leg, and moving the center of the mechanism, is presented. The concept of a gait for this mechanism is defined, and is used to show how extremely agile the mechanism can be. Specific resistance is employed as a way to explore the relative efficiency of this mechanism versus a wheel. Finally, we describe our first prototype rotopod and report …

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Rank-Based Multisensory Fusion In Multitarget Video Tracking, Damian M. Lyons, D. Frank Hsu Jul 2005

Rank-Based Multisensory Fusion In Multitarget Video Tracking, Damian M. Lyons, D. Frank Hsu

Faculty Publications

An attractive approach to improve tracking performance for visual surveillance is to use information from multiple visual sensory cues such as position, color, shape, etc. Previous work in fusion for tracking has tended to focus on fusion by numerically combining the scores assigned by each cue. We argue that for video scenes with many targets in a crowded situation, the splitting and merging of regions associated with targets, and the subsequent dramatic changes in cue values and reliabilities, renders this form of fusion less effective. In this paper we present experimental results showing that use of cue rank information in …

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Salient Closed Boundary Extraction With Ratio Contour, Song Wang, Toshiro Kubota, Jeffrey Mark Siskind, Jun Wang Apr 2005

Salient Closed Boundary Extraction With Ratio Contour, Song Wang, Toshiro Kubota, Jeffrey Mark Siskind, Jun Wang

Faculty Publications

We present ratio contour, a novel graph-based method for extracting salient closed boundaries from noisy images. This method operates on a set of boundary fragments that are produced by edge detection. Boundary extraction identifies a subset of these fragments and connects them sequentially to form a closed boundary with the largest saliency. We encode the Gestalt laws of proximity and continuity in a novel boundary-saliency measure based on the relative gap length and average curvature when connecting fragments to form a closed boundary. This new measure attempts to remove a possible bias toward short boundaries. We present a polynomial-time algorithm …

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A Dynamic Pruning And Feature Selection Strategy For Real-Time Tracking, D. Frank Hsu, Damian M. Lyons Mar 2005

A Dynamic Pruning And Feature Selection Strategy For Real-Time Tracking, D. Frank Hsu, Damian M. Lyons

Faculty Publications

Automated video tracking is useful in a number of applications such as surveillance, multisensor networks, robotics and virtual reality. In this paper we investigate an approach to tracking based on fusing the output of a collection of video trackers, each attending to a different feature or cue on the target. We show both theoretically and experimentally that the method used to prune the growth of target hypotheses can have a great impact on the trackers performance, and indirectly, change the benefit of using linear score combination as opposed to a non-linear rank combination for fusion. We also show that the …

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Delay-Constrained Transmission Of Fine Scalable Coded Content Over P2p Networks, Xiao Su, Yi Shang, Tao Wang, Yuqing Mai Jan 2005

Delay-Constrained Transmission Of Fine Scalable Coded Content Over P2p Networks, Xiao Su, Yi Shang, Tao Wang, Yuqing Mai

Faculty Publications

Images or videos are generally coded before transmission, and they can be either non-scalable coded or scalable coded, which can be further classified into fine-scalable coded and coarse-scalable coded. In this paper, we focus on delivery of fine-scalable coded content. The objective of our work is to design algorithms to optimize the quality of fine-scalable coded images or videos on peer-to-peer networks when a requesting peer is delay-sensitive and has to display content within a certain delay bound. Fine-scalable coding has two properties: (1) it embeds lower bit-rate bitstreams into higher bit-rate bitstreams; and (2) its coding quality increases with …

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Automatic Generation Of Social Network Data From Electronic-Mail Communications, Jason Yee, Robert F. Mills, Gilbert L. Peterson, Summer E. Bartczack Jan 2005

Automatic Generation Of Social Network Data From Electronic-Mail Communications, Jason Yee, Robert F. Mills, Gilbert L. Peterson, Summer E. Bartczack

Faculty Publications

Most organizations have formal and informal elements. Formal structures are usually documented in organizational charts showing chain of command, levels of authority, and personnel resources. The actual effectiveness of the organization or specific individuals may actually depend on informal structures and internal communication networks. These are by definition personality-dependent and may provide significant insight into how work actually gets done within the organization. Effective leaders will want insight into these informal structures for various reasons. Inefficient decision-making or staffing processes may result in unnecessary or redundant communications, chokepoints, or single points of failure, each of which can either delay decisions …

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Research Directions For Service-Oriented Multiagent Systems, Michael N. Huhns, Munindar P. Singh, Mark Burstein, Keith Decker, Edmund Durfee, Tim Finin, Les Gasser, Hrishikesh Goradia, Nick Jennings, Kiran Lakkaraju, Hideyuki Nakashima, H. Van Dyke Parunak, Jeffrey S. Rosenschein, Alicia Ruvinsky, Gita Sukthankar, Samarth Swarup, Katia Sycara, Milind Tambe, Tom Wagner, Laura Zavala, Mas Research Roadmap Project Jan 2005

Research Directions For Service-Oriented Multiagent Systems, Michael N. Huhns, Munindar P. Singh, Mark Burstein, Keith Decker, Edmund Durfee, Tim Finin, Les Gasser, Hrishikesh Goradia, Nick Jennings, Kiran Lakkaraju, Hideyuki Nakashima, H. Van Dyke Parunak, Jeffrey S. Rosenschein, Alicia Ruvinsky, Gita Sukthankar, Samarth Swarup, Katia Sycara, Milind Tambe, Tom Wagner, Laura Zavala, Mas Research Roadmap Project

Faculty Publications

Today's service-oriented systems realize many ideas from the research conducted a decade or so ago in multiagent systems. Because these two fields are so deeply connected, further advances in multiagent systems could feed into tomorrow's successful service-oriented computing approaches. This article describes a 15-year roadmap for service-oriented multiagent system research.

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A Semantic Web Services Architecture, Mark Burstein, Christoph Bussler, Michal Zaremba, Tim Finn, Michael N. Huhns, Massimo Paolucci, Amit P. Sheth, Stuart Williams Jan 2005

A Semantic Web Services Architecture, Mark Burstein, Christoph Bussler, Michal Zaremba, Tim Finn, Michael N. Huhns, Massimo Paolucci, Amit P. Sheth, Stuart Williams

Faculty Publications

The semantic Web services initiative architecture (SWSA) committee has created a set of architectural and protocol abstractions that serve as a foundation for semantic Web service technologies. This article summarizes the committee's findings, emphasizing its review of requirements gathered from several different environments. We also identify the scope and potential requirements for a semantic Web services architecture.

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Service-Oriented Computing: Key Concepts And Principles, Michael N. Huhns, Munindar P. Singh Jan 2005

Service-Oriented Computing: Key Concepts And Principles, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Traditional approaches to software development - the ones embodied in CASE tools and modeling frameworks - are appropriate for building individual software components, but they are not designed to face the challenges of open environments. Service-oriented computing provides a way to create a new architecture that reflects components' trends toward autonomy and heterogeneity. We thus emphasize SOC concepts instead of how to deploy Web services in accord with current standards. To begin the series, we describe the key concepts and abstractions of SOC and the elements of a corresponding engineering methodology.

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Every Polynomial-Time 1-Degree Collapses If And Only If P=Pspace, Stephen A. Fenner, Stuart A. Kurtz, James S. Royer Sep 2004

Every Polynomial-Time 1-Degree Collapses If And Only If P=Pspace, Stephen A. Fenner, Stuart A. Kurtz, James S. Royer

Faculty Publications

No abstract provided.

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Multiagent Systems With Workflows, José M. Vidal, Paul A. Buhler, Christian Stahl Jan 2004

Multiagent Systems With Workflows, José M. Vidal, Paul A. Buhler, Christian Stahl

Faculty Publications

Industry and researchers have two different visions for the future of Web services. Industry wants to capitalize on Web service technology to automate business processes via centralized workflow enactment. Researchers are interested in the dynamic composition of Web services. We show how these two visions are points in a continuum and discuss a possible path for bridging the gap between them.

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Image Segmentation With Ratio Cut, Song Wang, Jeffrey Mark Siskind Jun 2003

Image Segmentation With Ratio Cut, Song Wang, Jeffrey Mark Siskind

Faculty Publications

This paper proposes a new cost function, cut ratio, for segmenting images using graph-based methods. The cut ratio is defined as the ratio of the corresponding sums of two different weights of edges along the cut boundary and models the mean affinity between the segments separated by the boundary per unit boundary length. This new cost function allows the image perimeter to be segmented, guarantees that the segments produced by bipartitioning are connected, and does not introduce a size, shape, smoothness, or boundary-length bias. The latter allows it to produce segmentations where boundaries are aligned with image edges. Furthermore, the …

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Web Mining For Web Personalization, Magdalini Eirinaki, M. Vazirgiannis Feb 2003

Web Mining For Web Personalization, Magdalini Eirinaki, M. Vazirgiannis

Faculty Publications

Web personalization is the process of customizing a Web site to the needs of specific users, taking advantage of the knowledge acquired from the analysis of the user's navigational behavior (usage data) in correlation with other information collected in the Web context, namely, structure, content, and user profile data. Due to the explosive growth of the Web, the domain of Web personalization has gained great momentum both in the research and commercial areas. In this article we present a survey of the use of Web mining for Web personalization. More specifically, we introduce the modules that comprise a Web personalization …

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Identity Management, Duncan A. Buell, Ravi Sandhu Jan 2003

Identity Management, Duncan A. Buell, Ravi Sandhu

Faculty Publications

No abstract provided.

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The Sentient Web, Michael N. Huhns Jan 2003

The Sentient Web, Michael N. Huhns

Faculty Publications

In a startling revelation, a team of university scientists has reported that a network of computers has become conscious and sentient, and is beginning to assume control of online information system. In spite of the ominous tone typically chosen for dramatic effect, a sentient Web would be more helpful and much easier for people to use. An agent is an active, persistent software component that perceives, reasons, and acts, and whose actions include communication. Agents inherently take intentional actions based on sensory information and memories of past actions. All agents have necessary communication ability, but they do not necessarily possess …

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The Zen Of The Web, Jeff Heflin, Michael N. Huhns Jan 2003

The Zen Of The Web, Jeff Heflin, Michael N. Huhns

Faculty Publications

No abstract provided.

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Commitments Among Agents, Ashok U. Mallya, Michael N. Huhns Jan 2003

Commitments Among Agents, Ashok U. Mallya, Michael N. Huhns

Faculty Publications

Commitments are a powerful representation for modeling multiagent interactions. Previous approaches have considered the semantics of commitments and how to check compliance with them. However, these approaches do not capture some of the subtleties that arise in real-life applications such as e-commerce, in which contracts and institutions have implicit temporal references. In this column, we describe a rich representation for the temporal content of commitments that lets us capture realistic contracts and avoid ambiguities. Consequently, this approach lets us reason about whether, and at what point, a commitment is satisfied or breached, and whether it is or ever becomes unenforceable.

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Being And Acting Rational, Michael N. Huhns Jan 2003

Being And Acting Rational, Michael N. Huhns

Faculty Publications

Rationality alone is insufficient to specify agent design. Using economic theory, we can program agents to behave in ways that maximize their utility while responding to environmental changes. However, economic models for agents, although general in principle, are typically limited in practice because the value functions that are tractable essentially reduce an agent to acting selfishly. Building a stable social system from a collection of agents motivated by self-serving interests is difficult. Finally, understanding rationality and knowledge requires interdisciplinary results from artificial intelligence, distributed.

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Massive Deliberation, William H. Turkett Jr., John R. Rose, Michael N. Huhns Jan 2003

Massive Deliberation, William H. Turkett Jr., John R. Rose, Michael N. Huhns

Faculty Publications

Agents are proliferating on the Web, making it conceivable that their collective reasoning ability might someday be harnessed for robust decision-making. The hope is that massive deliberation power can soon help solve problems that require knowledge, reasoning, and intelligence. Until recently, working individually or in small groups, agents across the Web could barely communicate and could only reason under conditions of severely bounded rationality. Projects such as Agentcities showed that widespread heterogeneous agents could collaborate on specific predefined tasks and provide diverse agent-based services. When the tasks are dynamic, of long duration, and ill defined, however, success requires planning that …

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Consensus Software: Robustness And Social Good, Michael N. Huhns Jan 2003

Consensus Software: Robustness And Social Good, Michael N. Huhns

Faculty Publications

In this column I explore some far-reaching issues of software development that lie at the intersection of robust software and sociopolitical systems. These two areas might seem unrelated-and most software developers would likely be horrified to have politics intrude on their programming efforts-but the intersection occurs through these premises: software systems administer and control much of our societal infrastructure; people would appreciate and better accept that control if they had input into the nature of the control and the systems' behavior; designers can make software systems more robust through redundancy, in which different versions of software components might cover for …

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