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2003

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Articles 181 - 210 of 628

Full-Text Articles in Computer Sciences

Integrating Multiple 3d Views Through Frame-Of-Reference Interaction, Matthew D. Plumlee, Colin Ware Jul 2003

Integrating Multiple 3d Views Through Frame-Of-Reference Interaction, Matthew D. Plumlee, Colin Ware

Center for Coastal and Ocean Mapping

Frame-of-reference interaction consists of a unified set of 3D interaction techniques for exploratory navigation of large virtual spaces in nonimmersive environments. It is based on a conceptual framework that considers navigation from a cognitive perspective, as a way of facilitating changes in user attention from one reference frame to another, rather than from the mechanical perspective of moving a camera between different points of interest. All of our techniques link multiple frames of reference in some meaningful way. Some techniques link multiple windows within a zooming environment while others allow seamless changes of user focus between static objects, moving objects, …

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Video Clip Retrieval By Maximal Matching And Optimal Matching In Graph Theory, Yu-Xin Peng, Chong-Wah Ngo, Qing-Jie Dong, Zong-Ming Guo, Jian-Guo Xiao Jul 2003

Video Clip Retrieval By Maximal Matching And Optimal Matching In Graph Theory, Yu-Xin Peng, Chong-Wah Ngo, Qing-Jie Dong, Zong-Ming Guo, Jian-Guo Xiao

Research Collection School Of Computing and Information Systems

In this paper, a novel approach for automatic matching, ranking and retrieval of video clips is proposed. Motivated by the maximal and optimal matching theories in graph analysis, a new similarity measure of video clips is defined based on the representation and modeling of bipartite graph. Four different factors: visual similarity, granularity, interference and temporal order of shots are taken into consideration for similarity ranking. These factors are progressively analyzed in the proposed approach. Maximal matching utilizes the granularity factor to efficiently filter false matches, while optimal matching takes into account the visual, granularity and interference factors for similarity measure. …

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A Novel Scheme For Video Similarity Detection, Steven Hoi, Wei Wang, Michael R. Lyu Jul 2003

A Novel Scheme For Video Similarity Detection, Steven Hoi, Wei Wang, Michael R. Lyu

Research Collection School Of Computing and Information Systems

In this paper, a new two-phase scheme for video similarity detection is proposed. For each video sequence, we extract two kinds of signatures with different granularities: coarse and fine. Coarse signature is based on the Pyramid Density Histogram (PDH) technique and fine signature is based on the Nearest Feature Trajectory (NFT) technique. In the first phase, most of unrelated video data are filtered out with respect to the similarity measure of the coarse signature. In the second phase, the query video example is compared with the results of the first phase according to the similarity measure of the fine signature. …

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Trifocal Morphing, Angus M. K. Siu, Ada S. K. Wan, Rynson W. H. Lau, Chong-Wah Ngo Jul 2003

Trifocal Morphing, Angus M. K. Siu, Ada S. K. Wan, Rynson W. H. Lau, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Image morphing allows smooth transition between 2D images. However, one of the limitations of existing image morphing techniques is the lack of interaction - the viewpoints of the interpolated images are restrained to the line joining the optical centers of the source and the destination images. Another limitation of existing image morphing techniques is that shape warping often causes distortion due to barycentric mapping. In this paper, we present our trifocal morphing technique to address these problems. The new technique allows a user to change the viewpoint of the output images, i.e., increasing the degrees of freedom of interaction, and …

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Investigation Of Third Party Rights Service And Shibboleth Modification To Introduce The Service, Sanket Agrawal Jun 2003

Investigation Of Third Party Rights Service And Shibboleth Modification To Introduce The Service, Sanket Agrawal

Dartmouth College Master’s Theses

Shibboleth is an architecture to support inter-institutional sharing of electronic resources that are subject to access control. Codifying copyright in Shibboleth authorization policies is difficult because of the copyright exceptions which can be highly subjective. Third Party Rights Service is a high-level concept that has been suggested as a solution to approximate the exceptions of copyright law. In this thesis, I investigate the components of the Third Party Rights Service. I design and analyze a modified Shibboleth architecture based on these components. The resulting architecture allows for the phased addition of the resources to make use of the Third Party …

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Multi-Chart Geometry Images, P. V. Sander, Z. J. Wood, S. J. Gortler, H. Hoppe Jun 2003

Multi-Chart Geometry Images, P. V. Sander, Z. J. Wood, S. J. Gortler, H. Hoppe

Computer Science and Software Engineering

We introduce multi-chart geometry images, a new representation for arbitrary surfaces. It is created by resampling a surface onto a regular 2D grid. Whereas the original scheme of Gu et al. maps the entire surface onto a single square, we use an atlas construction to map the surface piecewise onto charts of arbitrary shape. We demonstrate that this added flexibility reduces parametrization distortion and thus provides greater geometric fidelity, particularly for shapes with long extremities, high genus, or disconnected components. Traditional atlas constructions suffer from discontinuous reconstruction across chart boundaries, which in our context create unacceptable surface cracks. Our solution …

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Open Problems From Cccg 2002, Erik D. Demaine, Joseph O'Rourke Jun 2003

Open Problems From Cccg 2002, Erik D. Demaine, Joseph O'Rourke

Computer Science: Faculty Publications

No abstract provided.

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A Generative Programming Framework For Adaptive Middleware, Venkita Subramonian, Christopher Gill Jun 2003

A Generative Programming Framework For Adaptive Middleware, Venkita Subramonian, Christopher Gill

All Computer Science and Engineering Research

Historically, many distributed real-time and embedded (DRE) systems were developed manually from scratch, leading to stove-piped solutions that while correct in both functional and QoS properties were very expensive to develop and difficult to maintain and extend. First-generation middleware technologies such as CORBA 2.x [1], XML [2], and SOAP [3], served to shield application developers from low-level platform details, thus raising the level of abstraction at which distributed systems are developed and supporting reuse of infrastructure to amortize development costs over the lifetime of a system. However, interdependencies between services and object interfaces resulting from these programming models significantly limited …

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Transformation: The Human Obstacles, Jens G. Pohl Jun 2003

Transformation: The Human Obstacles, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper addresses the human aspects of change at a time when the rapid wide-spread implementation of a new infostructure has become the cornerstone of national security policies. The author explores the behavioral characteristics of human beings from a point of view that is not based on inter-human comparisons, but on an examination of the innate physical, biological, intellectual, emotional, and social characteristics of our species. It is argued that the experience-based nature of the human cognitive system greatly reduces our ability to adapt to changes in our environment, exploit opportunities, and create new knowledge. A fundamental biological survival instinct …

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High Speed Video Capturing In The Area Of Earthquake Research, Thomas Wischgoll Jun 2003

High Speed Video Capturing In The Area Of Earthquake Research, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

No abstract provided.

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A Self-Adapting Healthcare Information Infrastructure Using Mobile Computing Devices, James K. Archibald, Eric S. Hall, Charles D. Knutson, David K. Vawdrey Jun 2003

A Self-Adapting Healthcare Information Infrastructure Using Mobile Computing Devices, James K. Archibald, Eric S. Hall, Charles D. Knutson, David K. Vawdrey

Faculty Publications

Despite recent improvements in the gathering and sharing of patient medical information among healthcare providers, there remains a gap in the electronic medical record infrastructure. Patient data is not available in some situations, either because the infrastructure is inaccessible (as in a natural disaster) or because there is no way to link the patient to the infrastructure (e.g., the patient cannot supply necessary identification information). This paper describes the Poket Doktor System, an architecture that allows an individual to carry personal electronic medical information on a wireless handheld device such as a smart card, cell phone, or PDA. Medical workers …

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Discrete-Event Fluid Modeling Of Background Tcp Traffic, David M. Nicol, Guanhua Yan Jun 2003

Discrete-Event Fluid Modeling Of Background Tcp Traffic, David M. Nicol, Guanhua Yan

Computer Science Technical Reports

TCP is the most widely used transport layer protocol used in the internet today. A TCP session adapts the demands it places on the network to observations of bandwidth availability on the network. Because TCP is adaptive, any model of its behavior that aspires to be accurate must be influenced by other network traffic. This point is especially important in the context of using simulation to evaluate some new network algorithm of interest (e.g. reliable multi-cast) in an environment where the background traffic affects---and is affected by---its behavior. We need to generate background traffic efficiently in a way that captures …

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 8, June 2003, College Of Engineering And Computer Science, Wright State University Jun 2003

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 8, June 2003, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

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802.11b Wireless Network Visualization And Radiowave Propagation Modeling, Chris Lentz Jun 2003

802.11b Wireless Network Visualization And Radiowave Propagation Modeling, Chris Lentz

Dartmouth College Undergraduate Theses

This paper outlines the methods of creating detailed coverage maps of 802.11b networks, with an emphasis on minimizing the expenses and time involved. The goal of this work is to develop and present a streamlined, reproducible approach to wireless visualization as well as techniques for predicting coverage area before conducting network installations. After evaluating these coverage maps, a repeated series of field measurements will be checked against interpolated values in order to improve techniques for extrapolation of data for unsampled regions. If successful, these extrapolation techniques will provide additional guidelines for, and assist modeling of, new wireless network installations. However, …

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An Evaluation Of The Impact Of Models For Radio Propagation On The Simulation Of 802.11b Wireless Networks, Evan W. Richardson Jun 2003

An Evaluation Of The Impact Of Models For Radio Propagation On The Simulation Of 802.11b Wireless Networks, Evan W. Richardson

Dartmouth College Undergraduate Theses

Working with an existing wireless network simulator, we describe the addition of both a method for modeling arbitrary terrain, and for calculating signal attenuation with the Irregular Terrain Model (ITM). We also investigate ITM's effects on upper protocol layer in comparison to the Two-Ray Ground Reflection model. Upon examination, it was found that aside from the terrain between the transmitter and receiver, ITM's various parameters are of little significance in the computed signal attenuation. Further, examination of the behavior of the upper protocol layers revealed that at high traffic levels, choice of propagation model can have significant effects on the …

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Power Conservation In The Network Stack Of Wireless Sensors, Michael De Rosa Jun 2003

Power Conservation In The Network Stack Of Wireless Sensors, Michael De Rosa

Dartmouth College Undergraduate Theses

Wireless sensor networks have recently become an incredibly active research area in the networking community. Much attention has been given to the construction of power-conserving protocols and techniques, as battery life is the one factor that prevents successful wide-scale deployment of such networks. These techniques concentrate on the optimization of network behavior, as the wireless transmission of data is the most expensive operation performed by a sensor node. Very little work has been published on the integration of such techniques, and their suitability to various application domains. This paper presents an exhaustive power consumption analysis of network stacks constructed with …

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Enhancing Asynchronous Parallel Computing, Elizabeth Anne Hamon Jun 2003

Enhancing Asynchronous Parallel Computing, Elizabeth Anne Hamon

Dartmouth College Undergraduate Theses

In applications using large amounts of data, hiding the latency inherent in accessing data far from the processor is often necessary in order to achieve high performance. Several researchers have observed that one way to address the challenge of latency is by using a common structure: in a series of passes, the program reads in the data, performs various operations on it, and writes out the data. Passes often consist of a pipeline structure composed of different stages. In order to achieve high performance, the stages are frequently overlapped, for example, by using asynchronous threads. Out-of-core parallel programs provide one …

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Adaptive Filters For Continuous Queries Over Distributed Data Stream, Chris Olston, Jing Jiang, Jennifer Widom Jun 2003

Adaptive Filters For Continuous Queries Over Distributed Data Stream, Chris Olston, Jing Jiang, Jennifer Widom

Research Collection School Of Computing and Information Systems

We consider an environment where distributed data sources continuously stream updates to a centralized processor that monitors continuous queries over the distributed data. Significant communication overhead is incurred in the presence of rapid update streams, and we propose a new technique for reducing the overhead. Users register continuous queries with precision requirements at the central stream processor, which installs filters at remote data sources. The filters adapt to changing conditions to minimize stream rates while guaranteeing that all continuous queries still receive the updates necessary to provide answers of adequate precision at all times. Our approach enables applications to trade …

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Distributed Planning And Control For Modular Robots With Unit-Compressible Modules, Zack Butler, Daniela Rus Jun 2003

Distributed Planning And Control For Modular Robots With Unit-Compressible Modules, Zack Butler, Daniela Rus

Computer Science Technical Reports

Self-reconfigurable robots are versatile systems consisting of large numbers of independent modules. Effective use of these systems requires parallel actuation and planning, both for efficiency and independence from a central controller. This paper presents the PacMan algorithm, a technique for distributed actuation and planning for systems with two- or three-dimensional unit-compressible modules. We give two versions of the algorithm along with correctness analysis. We also analyze the parallel actuation capability of the algorithm, showing that it will not deadlock and will avoid disconnecting the robot. We have implemented PacMan on the Crystal robot, a hardware system developed in our lab, …

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A Surface-Based Approach For Classification Of 3d Neuroanatomic Structures, Li Shen, James Ford, Fillia Makedon, Andrew Saykin Jun 2003

A Surface-Based Approach For Classification Of 3d Neuroanatomic Structures, Li Shen, James Ford, Fillia Makedon, Andrew Saykin

Computer Science Technical Reports

We present a new framework for 3D surface object classification that combines a powerful shape description method with suitable pattern classification techniques. Spherical harmonic parameterization and normalization techniques are used to describe a surface shape and derive a dual high dimensional landmark representation. A point distribution model is applied to reduce the dimensionality. Fisher's linear discriminants and support vector machines are used for classification. Several feature selection schemes are proposed for learning better classifiers. After showing the effectiveness of this framework using simulated shape data, we apply it to real hippocampal data in schizophrenia and perform extensive experimental studies by …

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Digital Art Forensics, Siwei Lyu, Daniel Rockmore, Hany Farid Jun 2003

Digital Art Forensics, Siwei Lyu, Daniel Rockmore, Hany Farid

Computer Science Technical Reports

We describe a computational technique for digitally authenticating works of art. This approach builds statistical models of an artist from a set of authenticated works. Additional works are then authenticated against this model. The statistical model consists of first- and higher-order wavelet statistics. We show preliminary results from our analysis of thirteen drawings by Pieter Bruegel the Elder. We also present preliminary results showing how these techniques may be applicable to determining how many hands contributed to a single painting.

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Efficient And Practical Constructions Of Ll/Sc Variables, Prasad Jayanti, Srdjan Petrovic Jun 2003

Efficient And Practical Constructions Of Ll/Sc Variables, Prasad Jayanti, Srdjan Petrovic

Computer Science Technical Reports

Over the past decade, LL/SC have emerged as the most suitable synchronization instructions for the design of lock-free algorithms. However, current architectures do not support these instructions; instead, they support either CAS or RLL/RSC (e.g. POWER4, MIPS, SPARC, IA-64). To bridge this gap, this paper presents two efficient wait-free algorithms for implementing 64-bit LL/SC objects from 64-bit CAS or RLL/RSC objects. Our first algorithm is practical: it has a small, constant time complexity (of 4 for LL and 5 for SC) and a space overhead of only 4 words per process. This algorithm uses unbounded sequence numbers. For theoretical interest, …

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Topological Features In Vector Fields, Thomas Wischgoll, Joerg Meyer Jun 2003

Topological Features In Vector Fields, Thomas Wischgoll, Joerg Meyer

Computer Science and Engineering Faculty Publications

No abstract provided.

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Adding Semantics To Web Services Standards, Kaarthik Sivashanmugam, Kunal Verma, Amit P. Sheth, John Miller Jun 2003

Adding Semantics To Web Services Standards, Kaarthik Sivashanmugam, Kunal Verma, Amit P. Sheth, John Miller

Kno.e.sis Publications

With the increasing growth in popularity of Web services, discovery of relevant Web services becomes a significant challenge. One approach is to develop semantic Web services where by the Web services are annotated based on shared ontologies, and use these annotations for semantics-based discovery of relevant Web services. We discuss one such approach that involves adding semantics to WSDL using DAML+OIL ontologies. Our approach also uses UDDI to store these semantic annotations and search for Web services based on them. We compare our approach with another initiative to add semantics to support Web service discovery, and show how our approach …

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Flow And Pressure Distributions In Vascular Networks Consisting Of Distensible Vessels, Gary S. Krenz, Christopher A. Dawson Jun 2003

Flow And Pressure Distributions In Vascular Networks Consisting Of Distensible Vessels, Gary S. Krenz, Christopher A. Dawson

Mathematics, Statistics and Computer Science Faculty Research and Publications

We examine the influence of vessel distensibility on the fraction of the total network flow passing through each vessel of a model vascular network. An exact computational methodology is developed yielding an analytic proof. For a class of structurally heterogeneous asymmetric vascular networks, if all the individual vessels share a common distensibility relation when the total network flow is changed, this methodology proves that each vessel will continue to receive the same fraction of the total network flow. This constant flow partitioning occurs despite a redistribution of pressures, which may result in a decrease in the diameter of one and …

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On Detecting Bandwidth Theft Attacks And Sla Violations In Qos Networks, Sonia Fahmy, Srinivas R. Avasarala, Venkatesh Prabhakar Jun 2003

On Detecting Bandwidth Theft Attacks And Sla Violations In Qos Networks, Sonia Fahmy, Srinivas R. Avasarala, Venkatesh Prabhakar

Department of Computer Science Technical Reports

No abstract provided.

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Towards Cost-Effective On-Demand Continuous Media Service: A Peer-To- Peer Approach, Yicheng Tu, Shan Lei Jun 2003

Towards Cost-Effective On-Demand Continuous Media Service: A Peer-To- Peer Approach, Yicheng Tu, Shan Lei

Department of Computer Science Technical Reports

No abstract provided.

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Recovery Performance Of Pgm With Redundancy Estimation For Proactive Fec, Sonia Fahmy, Renin M. Jegadeesan Jun 2003

Recovery Performance Of Pgm With Redundancy Estimation For Proactive Fec, Sonia Fahmy, Renin M. Jegadeesan

Department of Computer Science Technical Reports

No abstract provided.

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Vulnerabilities And Safe-Guards In Networks With Qos Support, Sonia Fahmy, Srinivas R. Avasarala, Venkatesh Prabhakar Jun 2003

Vulnerabilities And Safe-Guards In Networks With Qos Support, Sonia Fahmy, Srinivas R. Avasarala, Venkatesh Prabhakar

Department of Computer Science Technical Reports

No abstract provided.

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Deployment Considerations For The Tcp Vegas Congestion Control Algorithm, Sonia Fahmy, Mridul Sharma Jun 2003

Deployment Considerations For The Tcp Vegas Congestion Control Algorithm, Sonia Fahmy, Mridul Sharma

Department of Computer Science Technical Reports

No abstract provided.

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