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2004

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Articles 301 - 330 of 797

Full-Text Articles in Computer Sciences

Greenpass Radius Tools For Delegated Authorization In Wireless Networks, Sung Hoon Kim Jun 2004

Greenpass Radius Tools For Delegated Authorization In Wireless Networks, Sung Hoon Kim

Dartmouth College Master’s Theses

Dartmouth's Greenpass project extends how public key cryptography can be used to secure the wireless LAN with a RADIUS (Remote Authentication Dial In User Service) server that is responsible for handling authentication requests from clients (called supplicants in the 802.1x authentication model). This thesis describes the design and implementation of the authentication process of Greenpass, specifically what decisions are made in determining who is granted access and how a small modification of already existing protocols can be used to provide guest access in a way that better reflects how delegation of authority works in the real world. Greenpass takes advantage …

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A Novel Distributed Denial-Of-Service Detection Algorithm, Brett Tsudama Jun 2004

A Novel Distributed Denial-Of-Service Detection Algorithm, Brett Tsudama

Master's Theses

The applicability of implementing Ratio-based SYN Flood Detection (RSD) on a network processor is explored, and initial results are presented.

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Haptic Gdraw: A Fun And Easy To Use 3d Haptically Enhanced Sculpting Program, Rick Komerska, Colin Ware Jun 2004

Haptic Gdraw: A Fun And Easy To Use 3d Haptically Enhanced Sculpting Program, Rick Komerska, Colin Ware

Center for Coastal and Ocean Mapping

We have developed a simple haptically-enhanced 3D sculpting application which utilizes Hermite spline-based primitives as building blocks to construct more complex solid models. To accomplish this, we have constructed a VR work environment which is intuitive and whose control affordances are made clear through the use of graspable handles. Haptics is used to support handle selection and provide physical constraints on handle movements consistent with their visual affordances. Our goal is to demonstrate how relatively simple haptic force constraints can combine with a visually intuitive and compelling environment to enable a program that is fun and easy to use.

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A Secure Network Node Approach To The Policy Decision Point In Distributed Access Control, Geoffrey H. Stowe Jun 2004

A Secure Network Node Approach To The Policy Decision Point In Distributed Access Control, Geoffrey H. Stowe

Dartmouth College Undergraduate Theses

To date, the vast majority of access control research and development has been on gathering, managing, and exchanging information about users. But an equally important component which has yet to be fully developed is the Policy Decision Point - the system that decides whether an access request should be granted given certain attributes of the requestor. This paper describes the research and implementation of a new PDP system for an undergraduate honors project. This PDP system employs three unique features which differentiate it from existing technology: collaboration capabilities, trusted management, and interoperability with other access control systems. Security considerations and …

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Content-Based Framework For Component Libraries, Franz J. Kurfess, Ching Kang Cheng, Z. Y. Wang, L. Jololian Jun 2004

Content-Based Framework For Component Libraries, Franz J. Kurfess, Ching Kang Cheng, Z. Y. Wang, L. Jololian

Computer Science and Software Engineering

The construction of large software systems from existing components requires efficient access to possibly large collections of such components. In this paper, we present a content-based framework to organize this large collection of components in a semi-automatic fashion, according to an extensible user-defined ontology. Neural associative memories are used for fast, similarity-based access. Relevant characteristics of components are extracted and stored as a ``signature'' in such an associative memory, and during retrieval the closest matches to the query are indicated in very short time. In addition to content-based characteristics such as keywords, function and variable names, comments, and the location …

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Sweto: Large-Scale Semantic Web Test-Bed, Boanerges Aleman-Meza, Chris Halaschek, Amit P. Sheth, I. Budak Arpinar, Gowtham Sannapareddy Jun 2004

Sweto: Large-Scale Semantic Web Test-Bed, Boanerges Aleman-Meza, Chris Halaschek, Amit P. Sheth, I. Budak Arpinar, Gowtham Sannapareddy

Kno.e.sis Publications

The emergent Semantic Web community needs a common infrastructure for testing the scalability and quality of new techniques and software which use machine processable data. Since ontologies are a centerpiece of most approaches, we believe that for an accurate evaluation of tools for quality, scalability and performance, the research community needs a freely available ontology with a large description base. If the use of tools is to be for advanced semantic applications, such as those in business intelligence and national security, then instances in the knowledge base should be highly interconnected. Thus, we propose and describe a Semantic WEb Technology …

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Algorithmic Fusion Of Gene Expression Profiling For Diffuse Large B-Cell Lymphoma Outcome Prediction, Qiuming Zhu, Hongmei Cui, Kahai Cao, Wing C. Chan Jun 2004

Algorithmic Fusion Of Gene Expression Profiling For Diffuse Large B-Cell Lymphoma Outcome Prediction, Qiuming Zhu, Hongmei Cui, Kahai Cao, Wing C. Chan

Computer Science Faculty Publications

Many different methods and techniques have been investigated for the processing and analysis of microarray gene expression profiling datasets. It is noted that the accuracy and reliability of the results are often dependent on the measurement approaches applied, and no single measurement so far is guaranteed to generate a satisfactory result. In this paper, an algorithmic fusion approach is presented for extracting genes that are predictive to clinical outcomes (survival-fatal) of diffuse large B-cell lymphoma on a set of microarray data for gene expression profiling. The approach integrates a set of measurements from different aspects in terms of the discrepancy …

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Technological Implications For Privacy, David Kotz Jun 2004

Technological Implications For Privacy, David Kotz

Computer Science Technical Reports

The World-Wide Web is increasingly used for commerce and access to personal information stored in databases. Although the Web is ``just another medium'' for information exchange, the fact that all the information is stored in computers, and all of the activity happens in computers and computer networks, makes it easier (cheaper) than every to track users' activities. By recording and analyzing user's activities in the Web, activities that may seem to be quite private to many users, it is more likely than ever before that a person's privacy may be threatened. In this paper I examine some of the technology …

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Experimental Evaluation Of Wireless Simulation Assumptions, David Kotz, Calvin Newport, Robert S. Gray, Jason Liu, Yougu Yuan, Chip Elliott Jun 2004

Experimental Evaluation Of Wireless Simulation Assumptions, David Kotz, Calvin Newport, Robert S. Gray, Jason Liu, Yougu Yuan, Chip Elliott

Computer Science Technical Reports

All analytical and simulation research on ad~hoc wireless networks must necessarily model radio propagation using simplifying assumptions. Although it is tempting to assume that all radios have circular range, have perfect coverage in that range, and travel on a two-dimensional plane, most researchers are increasingly aware of the need to represent more realistic features, including hills, obstacles, link asymmetries, and unpredictable fading. Although many have noted the complexity of real radio propagation, and some have quantified the effect of overly simple assumptions on the simulation of ad~hoc network protocols, we provide a comprehensive review of six assumptions that are still …

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Quantifying Software Maintainability On Re-Engineered Translation Of Fortran To C++ Code, Zane Grey Tomlinson Jr. Jun 2004

Quantifying Software Maintainability On Re-Engineered Translation Of Fortran To C++ Code, Zane Grey Tomlinson Jr.

Theses and Dissertations

Due to the expanding existence of old software, legacy systems, and obsolete platforms with many industries, software re-engineering has become a widespread methodology that assists engineers and software practitioners with translating inflexible, unsupportable legacy software into maintainable software. Many companies today are investing in a variety of re-engineering techniques such as translation of source code to new code structures and target platforms to ensure future software maintenance can be performed in an efficient and effective manner. With sound re-engineering principles, the application of these techniques leverage the knowledge and previous engineering endeavors to mitigate risks and provide adequate performance to …

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Silhouette Lookup For Automatic Pose Tracking, Nicholas Howe Jun 2004

Silhouette Lookup For Automatic Pose Tracking, Nicholas Howe

Computer Science: Faculty Publications

Computers should be able to detect and track the articulated 3-D pose of a human being moving through a video sequence. Current tracking methods often prove slow and unreliable, and many must be initialized by a human operator before they can track a sequence. This paper introduces a simple yet effective algorithm for tracking articulated pose, based upon looking up observed silhouettes in a collection of known poses. The new algorithm runs quickly, can initialize itself without human intervention, and can automatically recover from critical tracking errors made while tracking previous frames in a video sequence.

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Development Of Web Tools For Nlx Simulation Software, Daniel Chai Siriphongs Jun 2004

Development Of Web Tools For Nlx Simulation Software, Daniel Chai Siriphongs

Loma Linda University Electronic Theses, Dissertations & Projects

Valuable mathematical equations have developed within biology and other sciences (physics, chemistry, etc.) that model various processes, but the complexity of the equations are not easily understood by students, scientists, and those with limited knowledge of the subject area. Simulation software used to visually explain a model is normally proprietary to the specific model equations and cannot be easily adapted to new models by non-programmers. Simulation software needs to be modular and based upon web technologies so that the software can be run on multiple platforms. The NLX simulation software is a group of Java-based objects that can be combined …

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Global Incremental Garbage Collection In Distributed Systems, Soha Safwat Labib Jun 2004

Global Incremental Garbage Collection In Distributed Systems, Soha Safwat Labib

Archived Theses and Dissertations

No abstract provided.

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Variations On Particle Swarm Optimization And Their Experimental Evaluation On Maximum Satisfiability, Susan A Abdelshahid Jun 2004

Variations On Particle Swarm Optimization And Their Experimental Evaluation On Maximum Satisfiability, Susan A Abdelshahid

Archived Theses and Dissertations

No abstract provided.

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On The Effects Of Device Mobility Upon Resource-Sharing In A Simulated Wireless Grid Network, Arris Ray Jun 2004

On The Effects Of Device Mobility Upon Resource-Sharing In A Simulated Wireless Grid Network, Arris Ray

Theses and Dissertations

The primary aim of modern computer networks is to permit simplified sharing of resources (e.g., files and data) or to provide access to remote resources (e.g., printers or remote file-systems). Grid networks aim to provide a more sophisticated framework for securely sharing, selecting and/or aggregating a wide-variety of remote resources, whether logical (e.g., files and data) or physical (e.g., remote sensors, processing power or disk storage space). Provided that circuit design continues to improve at the relatively steady pace that it has for the past decade, in addition to standard desktop systems, miniature and mobile devices will soon become substantially …

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Robust Security Mechnisms For Data Streams Systems, Mohamed Ali, Mohamed Eltabakh, Cristina Nita-Rotaru Jun 2004

Robust Security Mechnisms For Data Streams Systems, Mohamed Ali, Mohamed Eltabakh, Cristina Nita-Rotaru

Department of Computer Science Technical Reports

No abstract provided.

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On Time Synchronization In Multi-Hop Sensor Networks, Ossama Younis, Sonia Fahmy Jun 2004

On Time Synchronization In Multi-Hop Sensor Networks, Ossama Younis, Sonia Fahmy

Department of Computer Science Technical Reports

No abstract provided.

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An Inconsistency Sensitive Arrangement Algorithm For Algebraic Curves, Victor Milenkovic, Elisha Sacks Jun 2004

An Inconsistency Sensitive Arrangement Algorithm For Algebraic Curves, Victor Milenkovic, Elisha Sacks

Department of Computer Science Technical Reports

No abstract provided.

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Daisy: A Hybrid Architecture For Anonymity Systems, Chi-Bun Chan, Cristina Nita-Rotaru Jun 2004

Daisy: A Hybrid Architecture For Anonymity Systems, Chi-Bun Chan, Cristina Nita-Rotaru

Department of Computer Science Technical Reports

No abstract provided.

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A Sensor Fusion Approach For Meeting Detection, Jue Wang, Guanling Chen, David Kotz Jun 2004

A Sensor Fusion Approach For Meeting Detection, Jue Wang, Guanling Chen, David Kotz

Dartmouth Scholarship

In this paper we present a context-sensing component that recognizes meetings in a typical office environment. Our prototype detects the meeting start and end by combining outputs from pressure and motion sensors installed on the chairs. We developed a telephone controller application that transfers incoming calls to voice-mail when the user is in a meeting. Our experiments show that it is feasible to detect high-level context changes with ``good enough'' accuracy, using low-cost, off-the-shelf hardware, and simple algorithms without complex training. We also note the need for better metrics to measure context detection performance, other than just accuracy. We propose …

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Tournament Versus Fitness Uniform Selection, Shane Legg, Marcus Hutter, Akshat Kumar Jun 2004

Tournament Versus Fitness Uniform Selection, Shane Legg, Marcus Hutter, Akshat Kumar

Research Collection School Of Computing and Information Systems

In evolutionary algorithms a critical parameter that must be tuned is that of selection pressure. If it is set too low then the rate of convergence towards the optimum is likely to be slow. Alternatively if the selection pressure is set too high the system is likely to become stuck in a local optimum due to a loss of diversity in the population. The recent Fitness Uniform Selection Scheme (FUSS) is a conceptually simple but somewhat radical approach to addressing this problem - rather than biasing the selection towards higher fitness, FUSS biases selection towards sparsely populated fitness levels. In …

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Steganographic Schemes For File System And B-Tree, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou Jun 2004

Steganographic Schemes For File System And B-Tree, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou

Research Collection School Of Computing and Information Systems

While user access control and encryption can protect valuable data from passive observers, these techniques leave visible ciphertexts that are likely to alert an active adversary to the existence of the data. We introduce StegFD, a steganographic file driver that securely hides user-selected files in a file system so that, without the corresponding access keys, an attacker would not be able to deduce their existence. Unlike other steganographic schemes proposed previously, our construction satisfies the prerequisites of a practical file system in ensuring the integrity of the files and maintaining efficient space utilization. We also propose two schemes for implementing …

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A Sensor-Fusion Approach For Meeting Detection, Jue Wang, Guanling Chen, David Kotz Jun 2004

A Sensor-Fusion Approach For Meeting Detection, Jue Wang, Guanling Chen, David Kotz

Dartmouth Scholarship

In this paper we present a context-sensing component that recognizes meetings in a typical office environment. Our prototype detects the meeting start and end by combining outputs from pressure and motion sensors installed on the chairs. We developed a telephone controller application that transfers incoming calls to voice-mail when the user is in a meeting. Our experiments show that it is feasible to detect high-level context changes with “good enough” accuracy, using low-cost, off-the-shelf hardware, and simple algorithms without complex training. We also note the need for better metrics to measure context detection performance, other than just accuracy. We propose …

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The Complexity Of Uml: Differentiating Practical And Theoretical Complexity, J. Erickson, Keng Siau Jun 2004

The Complexity Of Uml: Differentiating Practical And Theoretical Complexity, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

UML (Unified Modeling Language) has been criticized for its complexity, relating to users, and those learning to use it. Using Rossi and Brinkkemper’s [9] complexity metrics, Siau and Cao [10] completed a complexity analysis of UML and 36 other modeling techniques, finding that UML is indeed more complex than other techniques. Siau, Erickson and Lee [11] argued that Rossi and Brinkkemper’s metrics present the theoretical maximum complexity, as opposed to a practitioner-based complexity, that must be less than the theoretical maximum. The current research proposes that a subset of UML (a kernel) composed of the most commonly used constructs, would …

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Furthering The Understanding Of Practical Complexity: Identifying A Kernel Of Uml, J. Erickson, Keng Siau Jun 2004

Furthering The Understanding Of Practical Complexity: Identifying A Kernel Of Uml, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

The Unified Modeling Language (UML) was adopted by the Object Management Group as the standard visual modeling language for OO systems development. However, UML has been criticized in the literature for its complexity, inconsistent semantics, and ambiguous constructs. A set of complexity indices for UML in aggregate, and the nine diagramming techniques individually, was compiled recently. Since this set of metrics is based on inclusion of all possible constructs in UML, it thus provides an indication of the theoretical (maximum) complexity of the modeling methods. This paper contends that in practice, developers do not use all of the possible diagrams …

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Parameter Inference Of Queueing Models For It Systems Using End-To-End Measurements, Laura Wynter, Cathy H. Xia, Fan Zhang Jun 2004

Parameter Inference Of Queueing Models For It Systems Using End-To-End Measurements, Laura Wynter, Cathy H. Xia, Fan Zhang

Research Collection School Of Computing and Information Systems

he scope of available applications, IT systems increase at a fascinating rate in both size and complexity. For example, today, a typical Web service hosting center may have hundreds of nodes and dozens of different applications simultaneously running on it. Each of the nodes in turn has often multiple processors and layered caches. These nodes make use of both local and shared storage systems. The size and complexity of such systems make performance modeling much more difficult, if at all tractable. Detailed modeling, fine tuning and accurate analysis can be carried out only on very small IT systems or very …

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Cryptanalysis Of Two Anonymous Buyer-Seller Watermarking Protocols And An Improvement For True Anonymity, Bok-Min Goi, Raphael C. W. Phan, Yanjiang Yang, Feng Bao, Robert H. Deng, M. U. Siddiqi Jun 2004

Cryptanalysis Of Two Anonymous Buyer-Seller Watermarking Protocols And An Improvement For True Anonymity, Bok-Min Goi, Raphael C. W. Phan, Yanjiang Yang, Feng Bao, Robert H. Deng, M. U. Siddiqi

Research Collection School Of Computing and Information Systems

By combining techniques of watermarking and fingerprinting, a sound buyer-seller watermarking protocol can address the issue of copyright protection in e-commerce. In this paper, we analyze the security of two recent anonymous buyer-seller watermarking protocols proposed by Ju et. al and Choi et. al respectively, and prove that they do not provide the features and security as claimed. In particular, we show that i) the commutative cryptosystem used in Choi et. als protocol fails to prevent the watermark certification authority (WCA) from discovering the watermark (fingerprint) chosen by the buyer; ii) for both protocols, the seller can discover the watermark …

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A Rate-Distortion Framework For Information-Theoretic Mobility Management, Abhishek Roy, Archan Misra, Sajal K. Das Jun 2004

A Rate-Distortion Framework For Information-Theoretic Mobility Management, Abhishek Roy, Archan Misra, Sajal K. Das

Research Collection School Of Computing and Information Systems

A practical information theoretic framework is developed for studying the optimal tradeoff between location update and paging costs in cellular networks. The framework envisions the quantization of location information into a registration area (RA) level granularity, followed by the use of an entropy-coding technique to decrease the location update rate. The rate distortion theory of the lossy quantization is identified as an appropriate measure for capturing the optimal tradeoff between a mobile's update rate and its location uncertainty. Based on LZ-78 compression, two different RA-level location update algorithms (RA-LeZi and LeZi-RA) have been developed, both of which asymptotically approach this …

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Proprietary And Open Systems Adoption In E-Procurement: A Risk-Augmented Transactions Cost Perspective, Robert J. Kauffman, Hamid Mohtadi Jun 2004

Proprietary And Open Systems Adoption In E-Procurement: A Risk-Augmented Transactions Cost Perspective, Robert J. Kauffman, Hamid Mohtadi

Research Collection School Of Computing and Information Systems

We present an economic model that enables the study of incentives for business-to-business (B2B) e-procurement systems investments that permit inventory coordination and improved operational control. We focus on the information technology adoption behavior of firms in the presence of transaction costs, agency costs and information uncertainty. We conclude that it is appropriate to rethink the prior theory and develop an extended transaction-cost theory perspective that incorporates the possibility of shocks. We distinguish among three kinds of B2B e-procurement systems platforms. Proprietary platform procurement systems involve traditional electronic data interchange (EDI) technologies. Open platform procurement systems are associated with e-market Web …

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Empirical Analysis Of Computational And Accuracy Tradeoffs Using Compactly Supported Radial Basis Functions For Surface Reconstruction, Weiming Liu, Bryan S. Morse, Lauralea Otis Jun 2004

Empirical Analysis Of Computational And Accuracy Tradeoffs Using Compactly Supported Radial Basis Functions For Surface Reconstruction, Weiming Liu, Bryan S. Morse, Lauralea Otis

Faculty Publications

Implicit surfaces can be constructed from scattered surface points using radial basis functions (RBFs) to interpolate the surface’s embedding function. Many researchers have used thin-plate spline RBFs for this because of their desirable smoothness properties. Others have used compactly supported RBFs, leading to a sparse matrix solution with lower computational complexity and better conditioning. However, the limited radius of support introduces a free parameter that leads to varying solutions as well as varying computational requirements: a larger radius of support leads to smoother and more accurate solutions but requires more computation. This paper presents an empirical analysis of this radius …

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