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2002

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Articles 31 - 60 of 497

Full-Text Articles in Computer Sciences

Measuring Packet Reordering, John M. Bellardo, Stefan Savage Nov 2002

Measuring Packet Reordering, John M. Bellardo, Stefan Savage

Computer Science and Software Engineering

The Internet architecture provides an unsequenced datagram delivery service. Nevertheless, many higher-layer protocols, such as TCP, assume that packets are usually delivered in sequence, and consequently suffer significant degradation when packets are reordered in flight. While there have been several recent proposals to create protocols that adapt to reordering, evaluating their effectiveness requires understanding the dynamics of the reordering processes prevalent in the Internet. Unfortunately, Internet packet sequencing is a poorly characterized and understudied behavior. This failing can be largely attributed to the lack of accurate and universally applicable methods for measuring packet reordering. In this paper, we describe a …

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 2, November 2002, College Of Engineering And Computer Science, Wright State University Nov 2002

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 2, November 2002, 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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A Pseudo Nearest-Neighbor Approach For Missing Data Recovery On Gaussian Random Data Sets, Xiaolu Huang, Qiuming Zhu Nov 2002

A Pseudo Nearest-Neighbor Approach For Missing Data Recovery On Gaussian Random Data Sets, Xiaolu Huang, Qiuming Zhu

Computer Science Faculty Publications

Missing data handling is an important preparation step for most data discrimination or mining tasks. Inappropriate treatment of missing data may cause large errors or false results. In this paper, we study the effect of a missing data recovery method, namely the pseudo- nearest neighbor substitution approach, on Gaussian distributed data sets that represent typical cases in data discrimination and data mining applications. The error rate of the proposed recovery method is evaluated by comparing the clustering results of the recovered data sets to the clustering results obtained on the originally complete data sets. The results are also compared with …

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Nsu Graduate Teacher Education Program (Gtep) Computer Science Education Courses 2002, Nova Southeastern University Nov 2002

Nsu Graduate Teacher Education Program (Gtep) Computer Science Education Courses 2002, Nova Southeastern University

Abraham S. Fischler College of Education and School of Criminal Justice College Archive

No abstract provided.

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Design And Implementation Of Interactive Tutorials For Data Structures, Ross Gore, Lewis Barnett Iii Nov 2002

Design And Implementation Of Interactive Tutorials For Data Structures, Ross Gore, Lewis Barnett Iii

Department of Math & Statistics Technical Report Series

The Tutorial Generation Toolkit (TGT) is a set of Java classes that supports authoring of interactive tutorial applications. This paper describes extensions to the capabilities of the TGT and several new tutorials aimed at the Data Structures course which were built using the toolkit.

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Evaluating Probabilistic Queries Over Imprecise Data, Reynold Cheng, Dmitri V. Kalashnikov, Sunil Prabhakar Nov 2002

Evaluating Probabilistic Queries Over Imprecise Data, Reynold Cheng, Dmitri V. Kalashnikov, Sunil Prabhakar

Department of Computer Science Technical Reports

No abstract provided.

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The Capacity Of Multi-Hop Wireless Networks With Tcp Regulated Traffic, Sorav Bansal, Rajeev Shorey, Shobhit Chugh, Anurag Goel, Kapil Kumar, Archan Misra Nov 2002

The Capacity Of Multi-Hop Wireless Networks With Tcp Regulated Traffic, Sorav Bansal, Rajeev Shorey, Shobhit Chugh, Anurag Goel, Kapil Kumar, Archan Misra

Research Collection School Of Computing and Information Systems

We study the dependence of the capacity of multi-hop wireless networks on the transmission range of nodes in the network with TCP regulated traffic. Specifically, we examine the sensitivity of the capacity to the speed of the nodes and the number of TCP connections in an ad hoc network. By incorporating the notion of a minimal acceptable QoS metric (loss) for an individual session, we argue that the QoS-aware capacity is a more accurate model of the TCP-centric capacity of an ad-hoc network. We study the dependence of capacity on the source application (Telnet or FTP) and on the choice …

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Defending Against Redirect Attacks In Mobile Ip, Robert H. Deng, Jianying Zhou, Feng Bao Nov 2002

Defending Against Redirect Attacks In Mobile Ip, Robert H. Deng, Jianying Zhou, Feng Bao

Research Collection School Of Computing and Information Systems

The route optimization operation in Mobile IP Version 6 (MIPv6) allows direct routing from any correspondent node to any mobile node and thus eliminates the problem of "triangle routing" present in the base Mobile IP Version 4 (MIPv4) protocol. Route optimization, however, requires that a mobile node constantly inform its correspondent nodes about its new care-of addresses by sending them binding update messages. Unauthenticated or malicious binding updates open the door for intruders to perform redirect attacks, i.e., malicious acts which redirect traffic from correspondent nodes to locations chosen by intruders. How to protect binding update messages to defend against …

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Modeling The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo Nov 2002

Modeling The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo

Faculty Publications

To support IP multicast, domains must assign a unique multicast address to each application from a limited, globally-shared address space. We examine the performance of several classes of address allocation algorithms withln the context of the MASC architecture. This study is the first of its kind to model the generalized multicast address allocation problem and consider non-contiguous allocation algorithms. We find that prefix-based allocation outperforms our non-contiguous algorithm, despite the apparent advantages of non-contiguous allocation. We also verify the benefits of using worst-fit for new allocations.

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A Theoretical Framework For The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo, Timothy Singer Nov 2002

A Theoretical Framework For The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo, Timothy Singer

Faculty Publications

The multicast address allocation problem requires Internet domains to allocate unique addresses to multicast applications from a globally-shared space. We develop a theoretical framework for multicast allocation algorithms that is influenced by subcube allocation in hypercube computer systems. Based on this framework we derive complexity results for the address allocation problem and describe several new allocation algorithms that use a hypercube model for address representation.

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Knowledge Discovery From Texts: A Concept Frame Graph Approach, Kanagasabai Rajaraman, Ah-Hwee Tan Nov 2002

Knowledge Discovery From Texts: A Concept Frame Graph Approach, Kanagasabai Rajaraman, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

We address the text content mining problem through a concept based framework by constructing a conceptual knowledge base and discovering knowledge therefrom. Defining a novel representation called the Concept Frame Graph (CFG), we propose a learning algorithm for constructing a CFG knowledge base from text documents. An interactive concept map visualization technique is presented for user-guided knowledge discovery from the knowledge base. Through experimental studies on real life documents, we observe that the proposed approach is promising for mining deeper knowledge.

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A Visual Tool For Building Logical Data Models Of Websites, Zehua Liu, Wee-Keong Ng, Feifei Li, Ee Peng Lim Nov 2002

A Visual Tool For Building Logical Data Models Of Websites, Zehua Liu, Wee-Keong Ng, Feifei Li, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Information sources over the WWW contain a large amount of data organized according to different interests and values. Thus, it is important that facilities are there to enable users to extract information of interest in a simple and effective manner. To do this, We propose the Wiccap Data Model, an XML data model that maps Web information sources into commonly perceived logical models, so that information can be extracted automatically according to users' interests. To accelerate the creation of data models, we have implemented a visual tool, called the Mapping Wizard, to facilitate and automate the process of producing Wiccap …

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Web Classification Using Support Vector Machine, Aixin Sun, Ee Peng Lim Nov 2002

Web Classification Using Support Vector Machine, Aixin Sun, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In web classification, web pages from one or more web sites are assigned to pre-defined categories according to their content. Since web pages are more than just plain text documents, web classification methods have to consider using other context features of web pages, such as hyperlinks and HTML tags. In this paper, we propose the use of Support Vector Machine (SVM) classifiers to classify web pages using both their text and context feature sets. We have experimented our web classification method on the WebKB data set. Compared with earlier Foil-Pilfs method on the same data set, our method has been …

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Motion-Based Video Representation For Scene Change Detection, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang Nov 2002

Motion-Based Video Representation For Scene Change Detection, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang

Research Collection School Of Computing and Information Systems

In this paper, we present a new framework to automatically group similar shots into one scene, where a scene is generally referred to as a group of shots taken place in the same site. Two major components in this framework are based on the motion characterization and background segmentation. The former component leads to an effective video representation scheme by adaptively selecting and forming keyframes. The later is considered novel in that background reconstruction is incorporated into the detection of scene change. These two components, combined with the color histogram intersection, establish our basic concept on assessing the similarity of …

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Predicting Bottleneck Bandwidth Sharing By Generalized Tcp Flows, Archan Misra, Teunis Ott, John Baras Nov 2002

Predicting Bottleneck Bandwidth Sharing By Generalized Tcp Flows, Archan Misra, Teunis Ott, John Baras

Research Collection School Of Computing and Information Systems

The paper presents a technique for computing the individual throughputs and the average queue occupancy when multiple TCP connections share a single bottleneck buffer. The bottleneck buffer is assumed to perform congestion feedback via randomized packet marking or drops. We first present a fixed point-based analytical technique to compute the mean congestion window sizes, the mean queue occupancy and the individual throughputs when the TCP flows perform idealized congestion avoidance. We subsequently extend the technique to analyze the case where TCP flows perform generalized congestion avoidance and demonstrate the use of this technique under the Assured Service model, where each …

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Mining Of Correlated Rules In Genome Sequences, L. Lin, L. Wong, Tze-Yun Leong, P. S. Lai Nov 2002

Mining Of Correlated Rules In Genome Sequences, L. Lin, L. Wong, Tze-Yun Leong, P. S. Lai

Research Collection School Of Computing and Information Systems

With the huge amount of data collected by scientists in the molecular genetics community in recent years, there exists a need to develop some novel algorithms based on existing data mining techniques to discover useful information from genome databases. We propose an algorithm that integrates the statistical method, association rule mining, and classification rule mining in the discovery of allelic combinations of genes that are peculiar to certain phenotypes of diseased patients.

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Horizon Occlusion Culling For Real-Time Rendering Of Hierarchical Terrains, Parris K. Egbert, Brandon Lloyd Oct 2002

Horizon Occlusion Culling For Real-Time Rendering Of Hierarchical Terrains, Parris K. Egbert, Brandon Lloyd

Faculty Publications

We present a technique to perform occlusion culling for hierarchical terrains at run-time. The algorithm is simple to implement and requires minimal pre-processing and additional storage, yet leads to 2-4 times improvement in framerate for views with high degrees of occlusion. Our method is based on the well-known occlusion horizon algorithm. We show how to adapt the algorithm for use with hierarchical terrains. The occlusion horizon is constructed as the terrain is traversed in an approximate front to back ordering. Regions of the terrain are compared to the horizon to determine when they are completely occluded from the viewpoint. Culling …

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Toward Interoperability Of Mobile Agent Systems, Arne Grimstrup, Robert Gray, David Kotz, Maggie Breedy, Marco Carvalho, Thomas Cowin, Daria Chacon, Joyce Barton, Chris Garrett, Martin Hofmann Oct 2002

Toward Interoperability Of Mobile Agent Systems, Arne Grimstrup, Robert Gray, David Kotz, Maggie Breedy, Marco Carvalho, Thomas Cowin, Daria Chacon, Joyce Barton, Chris Garrett, Martin Hofmann

Dartmouth Scholarship

Mobile agents are an increasingly popular paradigm and in recent years there has been a proliferation of mobile-agent systems. These systems are, however, largely incompatible with each other. In particular, agents cannot migrate to a host that runs a different mobile-agent system. Prior approaches to interoperability have tried to force agents to use a common API and so far none have succeeded. This goal led to our efforts to develop mechanisms that support dynamic runtime interoperability of mobile-agent systems. This paper describes the Grid Mobile-Agent System, which allows agents to migrate to different mobile-agent systems.

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Rf Rendez-Blue: Reducing Power And Inquiry Costs In Bluetooth-Enabled Mobile Systems, Eric S. Hall, Charles D. Knutson, David K. Vawdrey Oct 2002

Rf Rendez-Blue: Reducing Power And Inquiry Costs In Bluetooth-Enabled Mobile Systems, Eric S. Hall, Charles D. Knutson, David K. Vawdrey

Faculty Publications

In resource-limited mobile computing devices, Bluetooth wireless technology imposes a weighty burden due to inefficient power utilization and a sluggish device discovery process. Buttressing Bluetooth with Radio Frequency Identification (RFID) technology by performing an operation we call “Rendez-Blue” alleviates these limitations. In the Rendez-Blue process, an RFID signal is used as a cue to “wake-up” a sleeping Bluetooth radio. This ensures that the Bluetooth radio is active only when needed, significantly reducing power consumption. In addition, RFID is used to communicate Bluetooth device information, allowing the user to bypass the traditional 10.24-second discovery process.

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 1, October 2002, College Of Engineering And Computer Science, Wright State University Oct 2002

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 1, October 2002, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A sixteen 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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Semantic Web Services And Processes: Semantic Composition And Quality Of Service, Jorge Cardoso, Chistoph Bussler, Amit P. Sheth, Dieter Fensel Oct 2002

Semantic Web Services And Processes: Semantic Composition And Quality Of Service, Jorge Cardoso, Chistoph Bussler, Amit P. Sheth, Dieter Fensel

Kno.e.sis Publications

Web Services are increasingly being adapted by Enterprises as the new approach to component-based solutions for enterprise applications. They hold potential to transform Web from a collection of information resources to a distributed computing platform. Many enterprise applications, including those supporting e-commerce take a form of processes, which need to be created from individual Web Services and other software components.

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Kinematic Path-Planning For Formations Of Mobile Robots With A Nonholonomic Constraint, Timothy D. Barfoot, Christopher M. Clark, Stephen M. Rock, Gabriele M.T. D'Eleuterio Oct 2002

Kinematic Path-Planning For Formations Of Mobile Robots With A Nonholonomic Constraint, Timothy D. Barfoot, Christopher M. Clark, Stephen M. Rock, Gabriele M.T. D'Eleuterio

Computer Science and Software Engineering

A method of planning paths for formations of mobile robots with nonholonomic constraints is presented. The kinematics equations presented in this paper allow a general geometrical formation of mobile robots to be maintained while the group as a whole travels an arbitrary path. It is possible to represent a formation of mobile robots by a single entity with the same type of nonholonomic constraint as the individual members. Thus, any path-planner or control method may be used with the formation as would be applied to an individual robot. Equations are developed for changing the geometrical formation and hardware results are …

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Sensor-Assisted Video Mapping Of The Seafloor, Yuri Rzhanov, Lloyd C. Huff, Randy G. Cutter Jr., Larry A. Mayer Oct 2002

Sensor-Assisted Video Mapping Of The Seafloor, Yuri Rzhanov, Lloyd C. Huff, Randy G. Cutter Jr., Larry A. Mayer

Center for Coastal and Ocean Mapping

In recent years video surveys have become an increasingly important ground-truthing of acousticseafloor characterization and benthic habitat mapping studies. However, the ground-truthing and detailed characterization provided by video are still typically done using sparse sample imagery supplemented by physical samples. Combining single video frames in a seamless mosaic can provide a tool by which imagery has significant areal coverage, while at the same time showing small fauna and biological features at mm resolution. The generation of such a mosaic is a challenging task due to height variations of the imaged terrain and decimeter scale knowledge of camera position. This paper …

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Study Of Transport Properties Of Inas Using Monte Carlo Simulation, Satyanadh Gundimada Oct 2002

Study Of Transport Properties Of Inas Using Monte Carlo Simulation, Satyanadh Gundimada

Electrical & Computer Engineering Theses & Dissertations

The present research is aimed at ascertaining the usefulness of InAs semiconductor material for single photon avalanche photo detectors operating in the Geiger mode at 2 μm wavelengths. InAs is considered as the material suitable for the purpose because of its less bandgap and lower effective mass of the electrons when compared to other semiconductor materials presently in use. Hence, theoretically transient transport properties of bulk InAs are superior and the velocity overshoot phenomena stronger. InAs is a relatively less explored material when compared to other materials like GaAs. The choice of the material is justified with thorough exploration of …

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Yet Another Algorithm For Pitch Tracking (Yaapt), Kavita Kasi Oct 2002

Yet Another Algorithm For Pitch Tracking (Yaapt), Kavita Kasi

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a pitch detection algorithm that is extremely robust for both high quality and telephone speech. The kernel method for this algorithm is the Normalized Cross Correlation (NCCF) reported by David Talkin [16]. Major innovations include: processing of the original acoustic signal and a nonlinearly processed version of the signal to partially restore very weak F0 components; intelligent peak picking to select multiple F0 candidates and assign merit factors; and, incorporation of highly robust pitch contours obtained from smoothed versions of low frequency portions of spectrograms. Dynamic programming is used to find the ''best" pitch track among all …

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A Multilevel Neural Network Architecture For Digital Implementation Of A Face Recognition System Based On Eigenface Approach, Linda Rajan Oct 2002

A Multilevel Neural Network Architecture For Digital Implementation Of A Face Recognition System Based On Eigenface Approach, Linda Rajan

Electrical & Computer Engineering Theses & Dissertations

The design and development of the digital implementation of a multilevel feed forward neural network architecture for face recognition based on statistical features representing Eigenfaces is presented in this thesis. The architecture is divided into three parts: feature extractor, classifier and identifier, The Eigenface extractor architecture is developed based on an efficient design strategy in which all the M weight values corresponding to the Eigenfaces are generated simultaneously from M images representing the Eigen vectors and the test input image. The multilayer neural network classifier is trained using error backpropagation algorithm. A novel multilevel digital architecture is developed for the …

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Recurrent Neural Networks And Algorithms For Reconstruction Of Images From Noisy And/Or Partial Data, Ming-Jung Seow Oct 2002

Recurrent Neural Networks And Algorithms For Reconstruction Of Images From Noisy And/Or Partial Data, Ming-Jung Seow

Electrical & Computer Engineering Theses & Dissertations

In this thesis, modular architectures and neighborhood-distance based learning algorithms for fast and effective convergence with increased storage capacity of Hopfield neural networks are presented. The main objective of this research work is to better understand the function of recurrent neural networks and the influence of modularity within a network, and to design, implement, and test the performance of modular Hopfield neural networks for pattern association. Mathematical analysis and results are provided to show that the speed, storage capacity, and generalization capability of the recurrent networks are improved significantly by incorporating the modular architectures and learning algorithms. A new ratio …

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Distributed Algorithms For Guiding Navigation Across A Sensor Network, Qun Li, Michael Derosa, Daniela Rus Oct 2002

Distributed Algorithms For Guiding Navigation Across A Sensor Network, Qun Li, Michael Derosa, Daniela Rus

Computer Science Technical Reports

We develop distributed algorithms for self-reconfiguring sensor networks that respond to directing a target through a region. The sensor network models the danger levels sensed across its area and has the ability to adapt to changes. It represents the dangerous areas as obstacles. A protocol that combines the artificial potential field of the sensors with the goal location for the moving object guides the object incrementally across the network to the goal, while maintaining the safest distance to the danger areas. We report on hardware experiments using a physical sensor network consisting of Mote sensors.

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Understanding And Measuring Corporate Is Sophistication: An Exploratory Investigation Using Ground Theory, Deepak Khazanchi Oct 2002

Understanding And Measuring Corporate Is Sophistication: An Exploratory Investigation Using Ground Theory, Deepak Khazanchi

Information Systems and Quantitative Analysis Faculty Publications

This paper describes the results of an exploratory study that culminated in the development of a set of theoretical dimensions for “Corporate IS Sophistication”. These indicators were developed utilizing grounded theory to analyze archival corporate data and data from in-depth interviews with functional IT executives in two Norwegian and one North American firm.

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Object-Oriented Architecture For Concurrent Processes In A Port Simulation, Reejo Mathew Oct 2002

Object-Oriented Architecture For Concurrent Processes In A Port Simulation, Reejo Mathew

Electrical & Computer Engineering Theses & Dissertations

An architectural model to represent the resources and infrastructure within a cargo terminal, as well as to support the concurrent but opposite flow of cargo within the terminal, is presented in this thesis. The model supports the configuration of an individual cargo terminal according to its characteristics, as well as the processing involved in the simultaneous flow of cargo in opposite directions through the terminal. This is useful in the analysis of the flow of military cargo and aids the decision-making process to increase the efficiency and throughput of any military operation. This model has been developed with the aim …

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