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2002

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Articles 91 - 120 of 497

Full-Text Articles in Computer Sciences

Analysis Of A Campus-Wide Wireless Network, David Kotz, Kobby Essien Sep 2002

Analysis Of A Campus-Wide Wireless Network, David Kotz, Kobby Essien

Dartmouth Scholarship

Understanding usage patterns in wireless local-area networks (WLANs) is critical for those who develop, deploy, and manage WLAN technology, as well as those who develop systems and application software for wireless networks. This paper presents results from the largest and most comprehensive trace of network activity in a large, production wireless LAN. For eleven weeks we traced the activity of nearly two thousand users drawn from a general campus population, using a campus-wide network of 476 access points spread over 161 buildings. Our study expands on those done by Tang and Baker, with a significantly larger and broader population. \par …


On The Area Of Hypercube Layouts, Ronald I. Greenberg, Lee Guan Sep 2002

On The Area Of Hypercube Layouts, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

This paper precisely analyzes the wire density and required area in standard styles for the hypercube. It shows that the most natural, regular layout of a hypercube of N^2 nodes in the plane, in a NxN grid arrangement, uses floor(2N/3)+1 horizontal wiring tracks for each row of nodes. (In the process, we see that the number of tracks per row can be reduced by 1 with a less regular design, as can also be seen from an independent argument of Bezrukov et al.) This paper also gives a simple formula for the wire density at any cut position and a …


Cryptanalysis Of Some Hash Functions Based On Block Ciphers And Codes, Hongjun Wu, Feng Bao, Robert Huijie Deng Sep 2002

Cryptanalysis Of Some Hash Functions Based On Block Ciphers And Codes, Hongjun Wu, Feng Bao, Robert Huijie Deng

Research Collection School Of Computing and Information Systems

At PKC 2000, Inoue and Sakurai proposed some methods to design hash functions from block ciphers and codes (block codes and convolutional codes). They claimed that their hash functions are secure: 2(d-1)m/2 encryptions are necessary to find a collision, where d and m are the minimal distance of the code and the block size of block cipher, respectively. However, we show in this paper that a collision could be found with about a.2m encryptions, where a is a small number.


Pickup And Delivery Problem With Time Windows: Algorithms And Test Case Generation, Hoong Chuin Lau, Zhe Liang Sep 2002

Pickup And Delivery Problem With Time Windows: Algorithms And Test Case Generation, Hoong Chuin Lau, Zhe Liang

Research Collection School Of Computing and Information Systems

In the pickup and delivery problem with time windows (PDPTW), vehicles have to transport loads from origins to destinations respecting capacity and time constraints. In this paper, we present a two-phase method to solve the PDPTW. In the first phase, we apply a novel construction heuristics to generate an initial solution. In the second phase, a tabu search method is proposed to improve the solution. Another contribution of this paper is a strategy to generate good problem instances and benchmarking solutions for PDPTW, based on Solomon' s benchmark test cases for VRPTW. Experimental results show that our approach yields very …


Safe Robot Driving, Chuck Thorpe, Romuald Aufrere, Justin David Carlson, David Duggins, Terrence W. Fong, Jay Gowdy, John Kozar, Robert Maclachlan, Colin Mccabe, Christoph Mertz, Arne Suppe, Chieh Chih Wang, Teruko Yata Sep 2002

Safe Robot Driving, Chuck Thorpe, Romuald Aufrere, Justin David Carlson, David Duggins, Terrence W. Fong, Jay Gowdy, John Kozar, Robert Maclachlan, Colin Mccabe, Christoph Mertz, Arne Suppe, Chieh Chih Wang, Teruko Yata

Research Collection School Of Computing and Information Systems

The Navlab group at Carnegie Mellon University has a long history of development of automated vehicles and intelligent systems for driver assistance. The earlier work of the group concentrated on road following, cross-country driving, and obstacle detection. The new focus is on short-range sensing, to look all around the vehicle for safe driving. The current system uses video sensing, laser rangefinders, a novel light-stripe rangefinder, software to process each sensor individually, and a map-based fusion system. The complete system has been demonstrated on the Navlab 11 vehicle for monitoring the environment of a vehicle driving through a cluttered urban environment, …


A Label-Switching Packet Forwarding Architecture For Multi-Hop Wireless Lans, Arup Acharya, Archan Misra, Sorav Bansal Sep 2002

A Label-Switching Packet Forwarding Architecture For Multi-Hop Wireless Lans, Arup Acharya, Archan Misra, Sorav Bansal

Research Collection School Of Computing and Information Systems

A router in wired network typically requires multiple network interfaces to act as a router or a forwarding node. In an ad-hoc multi-hop wireless network on the other hand, any node with a wireless network interface card can operate as a router or a forwarding node, since it can receive a packet from a neighboring node, do a route lookup based on the packet's destination IP address, and then transmit the packet to another neighboring node using the same wireless interface. This paper investigates a combined medium access and next-hop address lookup based on fixed length labels (instead of IP …


Knowledge Discovery And Modeling In Genomic Databases, Michael M. Yin Aug 2002

Knowledge Discovery And Modeling In Genomic Databases, Michael M. Yin

Dissertations

This dissertation research is targeted toward developing effective and accurate methods for identifying gene structures in the genomes of high eukaryotes, such as vertebrate organisms. Several effective hidden Markov models (HMMs) are developed to represent the consensus and degeneracy features of the functional sites including protein-translation start sites, mRNA splicing junction donor and acceptor sites in vertebrate genes. The HMM system based on the developed models is fully trained using an expectation maximization (EM) algorithm and the system performance is evaluated using a 10-way cross-validation method. Experimental results show that the proposed HMM system achieves high sensitivity and specificity in …


Statistical Image Analysis Of Spotted Arrays, Filippo Posta Aug 2002

Statistical Image Analysis Of Spotted Arrays, Filippo Posta

Theses

There is a lot of systematic and specific variability in microarray experiments, this variability affects measured gene expression levels, leading to unreliable gene profiling or an heavy load of extra experiment to statistically confirm the data observed in one experiment.

The aim of this work is to systematically analyze, using statistics, the image derived from a cDNA microarray experiment to have a better understanding of this variability and thus a better confidence over the data obtained from an experiment.

Using technologies available at the Center for Applied Genomics, Newark, New Jersey. Selected images derived from different type of microarray experiments …


An Algorithm For Estimating The Quality Of Microarrays, Ajeet S. Sodhi Aug 2002

An Algorithm For Estimating The Quality Of Microarrays, Ajeet S. Sodhi

Theses

Microarray technology is currently one of the most valuable gene expression tools in molecular biology allowing the experimenter to simultaneously quantify the expression of thousands of genes. It is also one of the most difficult tools to use accurately as each microarray produces a large amount of information that needs to be inspected and normalized before analysis. As the size of a microarray or number of replicates increase, the use of manual inspection becomes impractical. The aim of this thesis is to introduce an algorithm that evaluates each feature of a microarray from the scanned data file. A quality score …


Intramural, Collaborative Learning Systems, Robert S. Friedman Aug 2002

Intramural, Collaborative Learning Systems, Robert S. Friedman

Theses

This thesis focuses on three related concepts: problem-based collaborative learning; the use of multimedia tools in learning systems; and participatory design as a software engineering methodology to create multimedia tools to be used in learning systems. A literature review of the three areas is followed by an overview of the pedagogical, technological, and business trends that affect the direction of innovation in education, including problem-based learning. A discussion of a software engineering project to develop a multimedia application that enhances the learning of geography skills and puts the programming, interface design and multimedia systems capabilities of college students into action …


Analysis For Cooperative Behavior Effectiveness Of Autonomous Wide Area Search Munitions, Sang M. Park Aug 2002

Analysis For Cooperative Behavior Effectiveness Of Autonomous Wide Area Search Munitions, Sang M. Park

Theses and Dissertations

The purpose of this study is to investigate how a simulation model can accurately represent the performance of the autonomous wide area search munitions, and to find the effectiveness of the cooperative behavior on the autonomous munitions. Though it does not provide a practical solution for the development of the autonomous wide area search munitions, this research will show some meaningful allocations of the munitions tasks that are applicable to the development of the autonomous munitions. For the first phase, this thesis presents how accurately a simplified simulation model can represent a proposed weapon system by comparing the simulation results …


Narendra Jaggi, Charlie Schlenker Aug 2002

Narendra Jaggi, Charlie Schlenker

Interviews for WGLT

Charlie Schlenker interviews Professor of Physics Narendra Jaggi about his work with computer modeling of ethnic living choices. (requires RealPlayer)


Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 5/16/02- 8/15/02, Yitung Chen, Randy Clarksean, Darrell Pepper Aug 2002

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 5/16/02- 8/15/02, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the AAA Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral to …


Algebraic Methods For Computer Aided Geometric Design, Thomas W. Sederberg, Jianmin Zheng Aug 2002

Algebraic Methods For Computer Aided Geometric Design, Thomas W. Sederberg, Jianmin Zheng

Faculty Publications

CAGD draws from several branches of mathematics and computer science, such as approximation theory, differential geometry, and numerical analysis. This chapter reviews some of the tools of algebra and algebraic geometry that have been brought to bear on problems in CAGD.


Object-Oriented Modeling And Fauly Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin Aug 2002

Object-Oriented Modeling And Fauly Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most critical components of a laser metal deposition system is the powder feeder unit. Techniques are required to efficiently design and analyze these systems and to ensure fault tolerance during the operation. In this paper, a model of the powder feeder unit, based on object- oriented abstractions of it components, is developed. This model is modular in that specific components can be efficiently updated or replaced with components that perform a similar function. In addition, the model can be used for simulation allowing for efficient design and analysis. Assurance of the correctness of the powder feeder system …


Object-Oriented Modeling And Fault Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin Aug 2002

Object-Oriented Modeling And Fault Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most critical components of a laser metal deposition system is the powder feeder unit. Techniques are required to efficiently design and analyze these systems and to ensure fault tolerance during the operation. In this paper, a model of the powder feeder unit, based on object-oriented abstractions of it components, is developed. This model is modular in that specific components can be efficiently updated or replaced with components that perform a similar function. In addition, the model can be used for simulation allowing for efficient design and analysis. Assurance of the correctness of the powder feeder system is …


Poet: The Online Preference Elicitation Tool, James Royalty, Robert Holland, Judy Goldsmith, Alex Dekhtyar Aug 2002

Poet: The Online Preference Elicitation Tool, James Royalty, Robert Holland, Judy Goldsmith, Alex Dekhtyar

Computer Science and Software Engineering

If the goal of eliciting accurate user preferences over a complex value space is to be realized, the elicitation process must be through while at the same time not overly burdensome to the user. An ideal preference elicitation tool would maximize the information about preferences acquired from the user while minimizing the number of queries required. To this end, we present POET: the Online Preference Elicitation Tool.
POET is a graphical Java applet designed to elicit complex preference structures to form a utility function. Once the elicitation process is complete POET outputs the resulting utility function as an XML …


Underwater Video Survey: Planning And Data Processing, Yuri Rzhanov, Lloyd C. Huff, Randy G. Cutter Jr. Aug 2002

Underwater Video Survey: Planning And Data Processing, Yuri Rzhanov, Lloyd C. Huff, Randy G. Cutter Jr.

Center for Coastal and Ocean Mapping

The importance of underwater video surveys as an exploration tool has been steadily increasing over recent years [1]. Better photographic equipment, more effective sources of illumination, and improved processing techniques - all make video surveying a reliable tool for seafloor habitat mapping, sediment boundary delineation and groundtruthing, mapping and documentation of forensic and archaeological sites. There is a change in attitude towards video surveying that affects the way the data is collected, and hence its quality. Earlier video data processing algorithms had to cope with whatever was recorded (often simultaneously with acquisition of other data, considered to be more important). …


Future Directions For Mobile-Agent Research, David Kotz, Robert Gray, Daniela Rus Aug 2002

Future Directions For Mobile-Agent Research, David Kotz, Robert Gray, Daniela Rus

Dartmouth Scholarship

The field of mobile agents should shift its emphasis toward mobile code, in all its forms, rather than continue focusing on mobile agents. The development of modular components will help application designers take advantage of code mobility without having to rewrite their applications to fit in monolithic, mobile agent systems.


Scalable And Reliable File Transfer For Clusters Using Multicast., Hardik Dikpal Shukla Aug 2002

Scalable And Reliable File Transfer For Clusters Using Multicast., Hardik Dikpal Shukla

Electronic Theses and Dissertations

A cluster is a group of computing resources that are connected by a single computer network and are managed as a single system. Clusters potentially have three key advantages over workstations operated in isolation—fault tolerance, load balancing and support for distributed computing.

Information sharing among the cluster’s resources affects all phases of cluster administration. The thesis describes a new tool for distributing files within clusters. This tool, the Scalable and Reliable File Transfer Tool (SRFTT), uses Forward Error Correction (FEC) and multiple multicast channels to achieve an efficient reliable file transfer, relative to heterogeneous clusters. SRFTT achieves scalability …


Organizing And Personalizing Intelligence Gathering From The Web, Hwee-Leng Ong, Ah-Hwee Tan, Jamie Ng, Pan Hong, Qiu-Xiang Li Aug 2002

Organizing And Personalizing Intelligence Gathering From The Web, Hwee-Leng Ong, Ah-Hwee Tan, Jamie Ng, Pan Hong, Qiu-Xiang Li

Research Collection School Of Computing and Information Systems

In this paper, we describe how an integrated web‐based application, code‐named FOCI (Flexible Organizer for Competitive Intelligence), can help the knowledge worker in the gathering, organizing, tracking and dissemination of competitive intelligence (CI). It combines the use of a novel user‐configurable clustering, trend analysis and visualization techniques to manage information gathered from the web. FOCI allows its users to define and personalize the organization of the information clusters according to their needs and preferences into portfolios. These personalized portfolios created are saved and can be subsequently tracked and shared with other users. The paper runs through an example to show …


Similarity Join For Low- And High-Dimensional Data, Dmitri V. Kalashnikov, Sunil Prabhakar Aug 2002

Similarity Join For Low- And High-Dimensional Data, Dmitri V. Kalashnikov, Sunil Prabhakar

Department of Computer Science Technical Reports

No abstract provided.


On Efficient On-Line Grouping Of Flows With Shared Bottlenecks At Loaded Servers, Ossama Younis, Sonia Fahmy Aug 2002

On Efficient On-Line Grouping Of Flows With Shared Bottlenecks At Loaded Servers, Ossama Younis, Sonia Fahmy

Department of Computer Science Technical Reports

No abstract provided.


Analyzing Unified Modeling Language Using Concept Mapping, Keng Siau, Z. Shen Aug 2002

Analyzing Unified Modeling Language Using Concept Mapping, Keng Siau, Z. Shen

Research Collection School Of Computing and Information Systems

The Unified Modeling Language (UML) is a visual modeling language for object-oriented software development. Although the Object Management Group (OMG) adopted UML as its standard modeling language in 1997, the consensus in the academic community and the industry is that further research is needed to evaluate, enhance, extend, and formalize UML. A substantial amount of research has been conducted to this end, but most was based on common sense, informal observation, and intuition. Systematic and empirical studies to analyze, evaluate, and enhance UML have been lacking. This paper attempts to evaluate and study UML from a cognitive perspective. Specifically, the …


Visual Execution Analysis For Multiagent Systems, Chong Kil Aug 2002

Visual Execution Analysis For Multiagent Systems, Chong Kil

Theses and Dissertations

Multiagent systems have become increasingly important in developing complex software systems. Multiagent systems introduce collective intelligence and provide benefits such as flexibility, scalability, decentralization, and increased reliability. A software agent is a high-level software abstraction that is capable of performing given tasks in an environment without human intervention. Although multiagent systems provide a convenient and powerful way to organize complex software systems, developing such system is very complicated. To help manage this complexity this research develops a methodology and technique for analyzing, monitoring and troubleshooting multiagent systems execution. This is accomplished by visualizing a multiagent system at multiple levels of …


Integrated Software System For The Collection And Evaluation Of Wellness Information., Rebecca Elizabeth Sweeney Aug 2002

Integrated Software System For The Collection And Evaluation Of Wellness Information., Rebecca Elizabeth Sweeney

Electronic Theses and Dissertations

There is an absence of a complete, easy to use, software system that can evaluate all areas of wellness. Although there are software programs and equipment available to examine certain aspects of wellness, they are incomplete. The solution to the difficulties of assessing wellness is the design and development of a software system that can be used to collect and evaluate wellness information. The system allows for complete reporting as it entails the six major components to wellness: demographics, body composition, lab work, nutritional intake, physical activity, and body measures. The system allows for ease of use by providing a …


A Formal Method To Analyze Framework-Based Software, Trent N. Larson Aug 2002

A Formal Method To Analyze Framework-Based Software, Trent N. Larson

Theses and Dissertations

Software systems are frequently designed using abstractions that make software verification tractable. Specifically, by choosing meaningful, formal abstractions for interfaces and then designing according to those interfaces, one can verify entire systems according to behavioral predicates. While impractical for systems in general, framework-based software architectures are a type of system for which formal analysis can be beneficial and practical over the life of the system. We present a method to formally analyze behavioral properties of framework-based software with higher-order logic and then demonstrate its utility for a significant, modern system.


Hci Research Issues In Electronic Commerce, Fiona Fui-Hoon Nah, Sid Davis Aug 2002

Hci Research Issues In Electronic Commerce, Fiona Fui-Hoon Nah, Sid Davis

Research Collection School Of Computing and Information Systems

This article outlines a number of important research issues in human-computer interaction in the e-commerce environment. It highlights some of the challenges faced by users in browsing Web sites and conducting searches for information, and suggests several areas of research for promoting ease of navigation and search. Also, it discusses the importance of trust in the online environment, describing some of the antecedents and consequences of trust, and provides guidelines for integrating trust into Web site design. The issues discussed in this article are presented under three broad categories of human-computer interaction – Web usability, interface design, and trust – …


Hcl: A Specification Language For Hierarchical Text Classification, Aixin Sun, Ee Peng Lim, Wee-Keong Ng Aug 2002

Hcl: A Specification Language For Hierarchical Text Classification, Aixin Sun, Ee Peng Lim, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

Hierarchical text classification refers to assigning text documents to the categories in a given category tree based on their content. With large number of categories organized as a tree, hierarchical text classification helps users to find information more quickly and accurately. Nevertheless, hierarchical text classification methods in the past have often been constructed in a proprietary manner. The construction steps often involve human efforts and are not completely automated. In this paper, we therefore propose a specification language known as HCL (Hierarchical Classification Language) . HCL is designed to describe a hierarchical classification method including the definition of a category …


Detection Of Slide Transition For Topic Indexing, Chong-Wah Ngo, Ting-Chuen Pong, Thomas S. Huang Aug 2002

Detection Of Slide Transition For Topic Indexing, Chong-Wah Ngo, Ting-Chuen Pong, Thomas S. Huang

Research Collection School Of Computing and Information Systems

This paper presents an automatic and novel approach in detecting the transitions of slides for video sequences of technical lectures. Our approach adopts a foreground vs background segmentation algorithm to separate a presenter from the projected electronic slides. Once a background template is generated, text captions are detected and analyzed. The segmented caption regions as well as background templates together provide salient visual cues to decide whether a slide is flipped and replaced. The partitioning of videos according to slide changes not only structure the content of video according to topics, but also facilitate the synchronization of video, audio and …