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2002

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Articles 91 - 120 of 208

Full-Text Articles in Computer Engineering

A Formal Object Model For Layered Networks To Support Verification And Simulation, Rasha M. B. E. Morsi Apr 2002

A Formal Object Model For Layered Networks To Support Verification And Simulation, Rasha M. B. E. Morsi

Electrical & Computer Engineering Theses & Dissertations

This work presents an abstract formal model of the interconnection structure of the Open Systems Interconnection Reference Model (OSI-RM) developed using Object-Oriented modeling principles permitting it to serve as a re-usable platform in supporting the development of simulations and formal methods applied to layered network protocols. A simulation of the object model using MODSIM III was developed and Prototype Verification System (PVS) was used to show the applicability of the object model to formal methods by formally specifying and verifying a Global Systems for Mobile communications (GSM) protocol. This application has proved to be successful in two aspects. The first …

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Analysis Of Ultra Wide Band (Uwb) Technology For An Indoor Geolocation And Physiological Monitoring System, Cengiz Alabacak Mar 2002

Analysis Of Ultra Wide Band (Uwb) Technology For An Indoor Geolocation And Physiological Monitoring System, Cengiz Alabacak

Theses and Dissertations

The goal of this research is to analyze the utility of UWB for indoor geolocation and to evaluate a prototype system, which will send information detailing a person’s position and physiological status to a command center. In a real world environment, geolocation and physiological status information needs to be sent to a command and control center that may be located several miles away from the operational environment. This research analyzes and characterizes the UWB signal in the various operational environments associated with indoor geolocation. Additionally, "typical usage scenarios" for the interaction between UWB and other devices are also tested and …

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Exact Bounds On Sample Variance Of Interval Data, Scott Ferson, Lev Ginzburg, Vladik Kreinovich, Monica Aviles Mar 2002

Exact Bounds On Sample Variance Of Interval Data, Scott Ferson, Lev Ginzburg, Vladik Kreinovich, Monica Aviles

Departmental Technical Reports (CS)

We provide a feasible (quadratic time) algorithm for computing the lower bound on the sample variance V of interval data. The problem of computing the upper bound on V is, in general, NP-hard. We provide a feasible algorithm that computes the upper bound on V for many reasonable situations.

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Detecting And Locating Curved Cracks In Thin Plates By Lamb Wave Reflection: Validated Geometric Approach, Roberto A. Osegueda, Vladik Kreinovich Mar 2002

Detecting And Locating Curved Cracks In Thin Plates By Lamb Wave Reflection: Validated Geometric Approach, Roberto A. Osegueda, Vladik Kreinovich

Departmental Technical Reports (CS)

Lamb waves propagate through a thin plate, and thus, provide a way of scanning this plate and detecting cracks and other faults. The equations describing these waves are rather complex, and, as a result, it is difficult to extract, from the received signal, the location of the fault. Recently, a new geometric approach has been proposed which allows, for linear cracks, to determine the presence and the location of a crack by using only the geometry of wave propagation. In this paper, we extend this approach to a more realistic case of curved cracks, and apply interval techniques to provide …

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 6, March 2002, College Of Engineering And Computer Science, Wright State University Mar 2002

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 6, March 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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Performance Evaluation Of Hyperbolic Position Location Technique In Cellular Wireless Networks, Hakan Senturk Mar 2002

Performance Evaluation Of Hyperbolic Position Location Technique In Cellular Wireless Networks, Hakan Senturk

Theses and Dissertations

This study addresses the wireless geolocation problem that has been an attractive subject for the last few years after Federal Communications Commission (FCC) mandate for wireless service providers to locate emergency 911 users with a high degree of accuracy -within a radius of 125 meters, 67 percent of the time by October 2001. There are a number of different geolocation technologies that have been proposed. These include, Assisted GPS (A-GPS), network-based technologies such as Enhanced Observed Time Difference (E-OTD), Time Difference of Arrival (TDOA), Angle of Arrival (AOA), and Cell of Origin (COO). This research focuses on network based techniques, …

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Wavelet Domain Communication System (Wdcs): Packet-Based Wavelet Spectral Estimation And M-Ary Signaling, Marion Jay F. Lee Mar 2002

Wavelet Domain Communication System (Wdcs): Packet-Based Wavelet Spectral Estimation And M-Ary Signaling, Marion Jay F. Lee

Theses and Dissertations

A recently proposed Wavelet Domain Communication System (WDCS) using transform domain processing demonstrated excellent interference avoidance capability under adverse environmental conditions. This work extends previous results by: 1) incorporating a wavelet packet decomposition technique, 2) demonstrating M-Ary signaling capability, and 3) providing increased adaptivity over a larger class of interference signals. The newly proposed packet-based WDCS is modeled and its performance characterized using MATLAB®. In addition, the WDCS response to two scenarios simulating Doppler effects and physical separation of transceivers are obtained. The fundamental metric for analysis and performance evaluation is bit error rate (Pb). Relative to …

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Fabrication Techniques For Micro-Optical Device Arrays, Ryan D. Conk Mar 2002

Fabrication Techniques For Micro-Optical Device Arrays, Ryan D. Conk

Theses and Dissertations

Micro-optical devices are vital components of conventional military data storage, sensor, and communication systems. Two types of micro-optical device arrays exist: individually addressable and matrix addressable. The matrix addressable array has a drastically reduced number of metal lines and can potentially be fabricated into large, dense (over 1k elements) arrays. Such arrays are expected to enable the development of extremely high bandwidth optical interconnect systems for future military applications including optical computing and short-haul fiber optical communication systems. I investigate new fabrication techniques for the assembly of dense matrix-addressed arrays of micro-optical devices such as vertical-cavity surface-emitting lasers. Using a …

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Diagnostics Of Bar And End-Ring Connector Breakage Faults In Polyphase Induction Motors Through A Novel Dual Track Of Time-Series Data Mining And Time-Stepping Coupled Fe-State Space Modeling, Richard J. Povinelli, John F. Bangura, Nabeel Demerdash, Ronald H. Brown Mar 2002

Diagnostics Of Bar And End-Ring Connector Breakage Faults In Polyphase Induction Motors Through A Novel Dual Track Of Time-Series Data Mining And Time-Stepping Coupled Fe-State Space Modeling, Richard J. Povinelli, John F. Bangura, Nabeel Demerdash, Ronald H. Brown

Electrical and Computer Engineering Faculty Research and Publications

This paper develops the fundamental foundations of a technique for detection of faults in induction motors that is not based on the traditional Fourier transform frequency domain approach. The technique can extensively and economically characterize and predict faults from the induction machine adjustable speed drive design data. This is done through the development of dual-track proof-of-principle studies of fault simulation and identification. These studies are performed using our proven Time Stepping Coupled Finite Element-State Space method to generate fault case data. Then, the fault cases are classified by their inherent characteristics, so-called “signatures” or “fingerprints.” These fault signatures are extracted …

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Integrated Manet Mutual Authentication System, Jason T. Ballah Mar 2002

Integrated Manet Mutual Authentication System, Jason T. Ballah

Theses and Dissertations

The Integrated MANET Mutual Authentication System (IMMAS) provides implied mutual authentication of all routing and data traffic within a Mobile Ad Hoc Network (MANET) by combining Elliptic Curve Cryptography, a public-key cryptosystem, with the Dynamic Source Routing (DSR) Protocol. IMMAS provides security by effectively hiding network topology from adversaries while reducing the potential for, among other things, traffic analysis and data tampering, all while providing a graceful degradation for each of the authentication components. Current research in MANETs tends to focus primarily on routing issues leaving topics such as security and authentication for future research. IMMAS focuses on achieving a …

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Performance Analysis Of A Dynamic Bandwidth Allocation Algorithm In A Circuit-Switched Communications Network, Timothy M. Schwamb Mar 2002

Performance Analysis Of A Dynamic Bandwidth Allocation Algorithm In A Circuit-Switched Communications Network, Timothy M. Schwamb

Theses and Dissertations

Military communications networks typically employ a gateway multiplexer to aggregate all communications traffic onto a single link. These multiplexers typically use a static bandwidth allocation method via time-division multiplexing (TDM). Inefficiencies occur when a high-bandwidth circuit, e.g., a video teleconferencing circuit, is relatively inactive rendering a considerable portion of the aggregate bandwidth wasted while inactive. Dynamic bandwidth allocation (DBA) reclaims unused bandwidth from circuits with low utilization and reallocates it to circuits with higher utilization without adversely affecting queuing delay. The proposed DBA algorithm developed here measures instantaneous utilization by counting frames arriving during the transmission time of a single …

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A Direct Sequence Code-Division Multiple-Access Local Area Network Model, James R. Rapallo Jr. Mar 2002

A Direct Sequence Code-Division Multiple-Access Local Area Network Model, James R. Rapallo Jr.

Theses and Dissertations

The United States Air Force relies heavily on computer networks for every-day operations. The medium access control (MAC) protocol currently used by most local area (LAN) permits a single station to access the network at a time (e.g. CSMA/CD or Ethernet). This limits network throughput to, at most, the maximum transmission rate of a single node with overhead neglected. Significant delays are observed when a LAN is overloaded by multiple users attempting to access the common medium. In CSMA/CD, collisions are detected and the data sent by the nodes involved are delayed and transmitted at a later time. The retransmission …

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Information Efficiency In Hyperspectral Imaging Systems, Stephen E. Reichenbach, Luyin Cao, Ram M. Narayanan Feb 2002

Information Efficiency In Hyperspectral Imaging Systems, Stephen E. Reichenbach, Luyin Cao, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

In this work we develop a method for assessing the information density and efficiency of hyperspectral imaging systems that have spectral bands of non-uniform width. Imaging system designs with spectral bands of nonuniform width can efficiently gather information about a scene by allocating bandwidth among the bands according to their information content. The information efficiency is the ratio of information density to data density and is a function of the scene’s spectral radiance, hyperspectral system design, and signal-to-noise ratio. The assessment can be used to produce an efficient system design. For example, one approach to determining the number and width …

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Nanostructures With Small- And Large-Scale Periodic And Random Rough Surfaces And Lateral Fluctuations In The Permittivity And Permeability-Scattered Near Fields, Ezekiel Bahar Feb 2002

Nanostructures With Small- And Large-Scale Periodic And Random Rough Surfaces And Lateral Fluctuations In The Permittivity And Permeability-Scattered Near Fields, Ezekiel Bahar

Department of Electrical and Computer Engineering: Faculty Publications

The scattered electromagnetic near fields due to fluctuations in the surface height and/or lateral variations in the electromagnetic medium parameters are evaluated using a full-wave approach. Since the scales of the height and medium fluctuations considered could be significantly smaller or larger than the electromagnetic wavelengths, the familiar perturbation and physical/geometrical optics solutions cannot be used nor is it possible to investigate subwave length features based on far-field measurements. The full-wave approach employs complete field expansion that includes propagating and evanescent waves as well as lateral waves and surface waves, which are not accounted for in the perturbation and physical …

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Optimization Techniques Under Uncertain Criteria, And Their Possible Use In Computerized Education, Vladik Kreinovich, Richard Alo Feb 2002

Optimization Techniques Under Uncertain Criteria, And Their Possible Use In Computerized Education, Vladik Kreinovich, Richard Alo

Departmental Technical Reports (CS)

The existing successful automated computerized systems more or less simulate the way successful human teachers teach. However, computerized systems provide more individualized options that traditional classroom education, and it is desirable to use this additional freedom to further improve the education success rate. In this papers, we briefly overview the experience of a successful Russian training system, and explain how general techniques of optimization under uncertainty can be used to optimize the content development.

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 5, February 2002, College Of Engineering And Computer Science, Wright State University Feb 2002

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 5, February 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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The Modified Hash Chain Sealed Bid Auction Protocol, Riham Hassan Abdel-Moneim Feb 2002

The Modified Hash Chain Sealed Bid Auction Protocol, Riham Hassan Abdel-Moneim

Archived Theses and Dissertations

No abstract provided.

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Introduction On Intrusion Detection Systems : Focus On Hierarchical Analysis, Ratna Bajaj Jan 2002

Introduction On Intrusion Detection Systems : Focus On Hierarchical Analysis, Ratna Bajaj

Theses

In today's fast paced computing world security is a main concern. Intrusion detection systems are an important component of defensive measures protecting computer systems and networks from abuse. This paper will examine various intrusion detection systems. The task of intrusion detection is to monitor usage of a system and detect and malicious activity, therefore, the architecture is a key component when studying intrusion detection systems. This thesis will also analyze various neural networks for statistical anomaly intrusion detection systems. The thesis will focus on the Hierarchical Intrusion Detection system (HIDE) architecture. The HIDE system detects network based attack as anomalies …

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Attack Visualization For Intrusion Detection System, Mohammad A. Rabie Jan 2002

Attack Visualization For Intrusion Detection System, Mohammad A. Rabie

Theses

Attacks detection and visualization is the process of attempting to identify instances of network misuse by comparing current activity against the expected actions of an intruder. Most current approaches to attack detection involve the use of rule-based expert systems to identify indications of known attacks. However, these techniques are less successful in identifying attacks, which vary from expected patterns. Artificial neural networks provide the potential to identify and classify network activity based on limited, incomplete, and nonlinear data sources. Presenting an approach to the process of Attack visualization that utilizes the analytical strengths of neural networks, and providing the results …

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Cxquery: A Novel Xml Query Language, Peter Revesz, Yi Chen Jan 2002

Cxquery: A Novel Xml Query Language, Peter Revesz, Yi Chen

School of Computing: Conference and Workshop Papers

XML is becoming the data exchange standard on the Internet. Previously proposed XML query languages, such as XQuery, Quilt, YALT, Lorel, and XML-QL, lack schema definition of the query result; therefore, they are limited for defining views, integrating data, updating, and further querying, all of which are often needed in e-Business applications. We propose a novel XML query language called CXQuery, which defines the schema of the query results explicitly and can easily define views, and integrate, update, and query XML data. In addition, CXQuery can express spatial and spatio-temporal queries using a constraint-based querying approach.

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Implementation Of A Si/Sic Hybrid Optically Controlled High-Power Switching Device, Prashant Bhadri, Kuntao Ye, Elena A. Guliants, Fred R. Beyette Jr. Jan 2002

Implementation Of A Si/Sic Hybrid Optically Controlled High-Power Switching Device, Prashant Bhadri, Kuntao Ye, Elena A. Guliants, Fred R. Beyette Jr.

Electrical and Computer Engineering Faculty Publications

The ever-increasing performance and economy of operation requirements placed on commercial and military transport aircraft are resulting in very complex systems. As a result, the use of fiber optic component technology has lead to high data throughput, immunity to EMI, reduced certification and maintenance costs and reduced weight features. In particular, in avionic systems, data integrity and high data rates are necessary for stable flight control. Fly-by-Light systems that use optical signals to actuate the flight control surfaces of an aircraft have been suggested as a solution to the EMI problem in avionic systems. Current fly-by-light systems are limited by …

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Enabling Dynamic Market-Managed Qos Interconnection In The Next Generation Internet By A Modified Bgp Mechanism, Junseok Hwang, Jorn Altmann, Huw Oliver, Alfonso Suarez Jan 2002

Enabling Dynamic Market-Managed Qos Interconnection In The Next Generation Internet By A Modified Bgp Mechanism, Junseok Hwang, Jorn Altmann, Huw Oliver, Alfonso Suarez

School of Information Studies - Faculty Scholarship

We propose a market-managed QoS (Quality of Service) interconnection model for heterogeneous networking environments. The deployment of this model will help autonomous systems to reduce the cost of their network services as well as increase social welfare. We describe a technical solution for a next generation Internet, where networks are managed based on either technology requirements (QoS networks) or market principles (market-managed networks). Our solution requires two technologies: BMP (Bandwidth Management Point) and a modified version of BGP (Border Gateway Protocol). The modified version of BGP, as proposed in this paper, provides additional routing exchange information such as price and …

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 4, January 2002, College Of Engineering And Computer Science, Wright State University Jan 2002

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 4, January 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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Translation Of 'Balika Badhu: A Selected Anthology Of Bengali Short Stories', Monish Ranjan Chatterjee Jan 2002

Translation Of 'Balika Badhu: A Selected Anthology Of Bengali Short Stories', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

This project, which began with the desire to render into English a rather long tale by Bimal Kar about five years ago, eventually grew into a considerably more extended compilation of Bengali short stories by 10 of the most well-known practitioners of that art since the heyday of Rabindranath Tagore. The collection is limited in many ways, not the least of which being that no woman writer has been included, and that it contains only a baker's dozen stories (if we count Bonophool's micro-stories collectively as one ) — a number pitifully small considering the vast and prolific field of …

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Exploring Strengths And Limits On Open Source Software Engineering Processes: A Research Agenda, Kevin Crowston, Barbara Scozzi Jan 2002

Exploring Strengths And Limits On Open Source Software Engineering Processes: A Research Agenda, Kevin Crowston, Barbara Scozzi

School of Information Studies - Faculty Scholarship

Many researchers have investigated the nature and characteristics of open source software (OSS) projects and their developer communities. In this position paper, after examining some success factors, we discuss potential limits on the replicability and portability of OSS engineering processes. Based on this analysis, we propose a research agenda to better understand the current nature of the processes and thus the strengths and the limitations.

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Model Scheme A Good Fit For C4isr, Andreas Tolk Jan 2002

Model Scheme A Good Fit For C4isr, Andreas Tolk

Computational Modeling & Simulation Engineering Faculty Publications

No abstract provided.

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On The Optimal Choice Of Quality Metric In Image Compression, Olga Kosheleva, Vladik Kreinovich, Yeung Yam Jan 2002

On The Optimal Choice Of Quality Metric In Image Compression, Olga Kosheleva, Vladik Kreinovich, Yeung Yam

Departmental Technical Reports (CS)

No abstract provided.

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Open-Ended Configurations Of Radio Telescopes: Towards Optimal Design, Vladik Kreinovich, Scott A. Starks, Olga Kosheleva, Andrei Finkelstein Jan 2002

Open-Ended Configurations Of Radio Telescopes: Towards Optimal Design, Vladik Kreinovich, Scott A. Starks, Olga Kosheleva, Andrei Finkelstein

Departmental Technical Reports (CS)

The quality of radio astronomical images drastically depends on where we place the radio telescopes. During the design of the Very Large Array, it was empirically shown that the power law design, in which n-th antenna is placed at a distance n^b from the center, leads to the best image quality. In this paper, we provide a theoretical justification for this empirical fact.

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Open-Ended Configurations Of Radio Telescopes: Geometrical Analysis, Vladik Kreinovich, Scott A. Starks, Dima Iourinski, Olga Kosheleva, Andrei Finkelstein Jan 2002

Open-Ended Configurations Of Radio Telescopes: Geometrical Analysis, Vladik Kreinovich, Scott A. Starks, Dima Iourinski, Olga Kosheleva, Andrei Finkelstein

Departmental Technical Reports (CS)

No abstract provided.

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Was There Satan's Face In The World Trade Center Fire? A Geometric Analysis, Vladik Kreinovich, Dima Iourinski Jan 2002

Was There Satan's Face In The World Trade Center Fire? A Geometric Analysis, Vladik Kreinovich, Dima Iourinski

Departmental Technical Reports (CS)

Some photos of the 2001 World Trade Center fire reveal a "face" in the smoke which was interpreted, by some people, as the face of Satan. Most journalists believe, however, that the visible smoke configuration can be explained by natural processes, and that the visible "face" is similar to animal shapes that are sometimes observed in the clouds. In this paper, we present a simple geometric analysis that supports this natural-process explanation.

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