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Computer Engineering Commons

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1996

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Articles 1 - 30 of 72

Full-Text Articles in Computer Engineering

Trade-Off Study And Computer Simulation For Assessing Spacecraft Pointing Accuracy And Stability Capabilities, Marcelo C. Algrain, Richard M. Powers Dec 1996

Trade-Off Study And Computer Simulation For Assessing Spacecraft Pointing Accuracy And Stability Capabilities, Marcelo C. Algrain, Richard M. Powers

Faculty Publications from the Department of Electrical and Computer Engineering

A case study, written in a tutorial manner, is presented where a comprehensive computer simulation is developed to determine the driving factors contributing to spacecraft pointing accuracy and stability. Models for major system components are described. Among them are spacecraft bus, attitude controller, reaction wheel assembly, star-tracker unit, inertial reference unit, and gyro drift estimators (Kalman filter). The predicted spacecraft performance is analyzed for a variety of input commands and system disturbances. The primary deterministic inputs are the desired attitude angles and rate set points. The stochastic inputs include random torque disturbances acting on the spacecraft, random gyro bias noise ...


Ellipsometer/Polarmeterbased Process Monitor And Control System Suitable For Simultaneous Retrofit On Molecular Beam Epitaxy System Rheed/Leed Interface System, And Method Of Use, John A. Woollam, Blaine D. Johs, Peter P. Chow Dec 1996

Ellipsometer/Polarmeterbased Process Monitor And Control System Suitable For Simultaneous Retrofit On Molecular Beam Epitaxy System Rheed/Leed Interface System, And Method Of Use, John A. Woollam, Blaine D. Johs, Peter P. Chow

Faculty Publications from the Department of Electrical and Computer Engineering

A method of, and system for applying light beam producing systems, such as ellipsometers, polarimeters, polarized light reflectance and functionally similar systems, such that a beam of light produced thereby is caused to be incident upon a process element at an angle in excess of an associated Brewster angle while enabling the production of a signal sufficiently sensitive to changes in process element parameters, for use in "real-time" process element process monitoring and control, is disclosed. In addition, a process element processing system and electron beam producing system and light beam producing system combination system is taught, wherein the electron ...


Detection For A Statistically-Known, Time-Varying Dispersive Channel, David W. Matolak, S. G. Wilson Dec 1996

Detection For A Statistically-Known, Time-Varying Dispersive Channel, David W. Matolak, S. G. Wilson

Faculty Publications

Detection for the statistically known channel (SKC) is aimed at obtaining good performance in situations where our statistical knowledge of a time-varying channel is good, and where other equalization/detection schemes are either too complex to implement, or their performance is limited due to the rapidity of channel fading, or where we are simply unable to perform channel estimation. By using a statistical characterization of the channel, we develop a new detector that performs maximum-likelihood sequence estimation (MLSE) (given the channel model) on blocks of N symbols. Both symbol-spaced and fractionally spaced samples are used, to obtain two different detectors ...


A Specialization Toolkit To Increase The Diversity Of Operating Systems, Calton Pu, Andrew P. Black, Crispin Cowan, Jonathan Walpole, Charles Consel Dec 1996

A Specialization Toolkit To Increase The Diversity Of Operating Systems, Calton Pu, Andrew P. Black, Crispin Cowan, Jonathan Walpole, Charles Consel

Computer Science Faculty Publications and Presentations

Virus and worm attacks that exploit system implementation details can be countered with a diversified set of implementations. Furthermore, immune systems show that attacks from previously unknown organisms require effective dynamic response. In the Synthetix project, we have been developing a specialization toolkit to improve the performance of operating system kernels. The toolkit helps programmers generate and manage diverse specialized implementations of software modules. The Tempo-C specializer tool generates different versions for both compile-time and run-time specialization. We are now adapting the toolkit to improve operating system survivability against implementations attacks.


Controlling Three-Axis Attitude Rates On A Pointing System Using Nonlinear Observer And Two Axis Measurements, Marcelo C. Algrain Nov 1996

Controlling Three-Axis Attitude Rates On A Pointing System Using Nonlinear Observer And Two Axis Measurements, Marcelo C. Algrain

Faculty Publications from the Department of Electrical and Computer Engineering

A new observer design method that allows for estimating the angular rates along a vehicle’s three principal axes is described. The observer uses measurements from a single two-axis angular rate sensor (gyro) and determines the rates for the third axis using a nonlinear observer. Unlike conventional approaches where the equations governing vehicle motion (Euler’s equations) are linearized and then an observer is constructed based on the linear model, this method does not require linearization of the system. Instead, a pseudo-linear representation is used. The pseudo-linear model is obtained by systematically decomposing a nonlinear system into linear and nonlinear ...


Application Of Inversions To Lossless Image Compression, Ziya Arnavut Nov 1996

Application Of Inversions To Lossless Image Compression, Ziya Arnavut

Faculty Publications from the Department of Electrical and Computer Engineering

Linear prediction schemes, such as that of the Joint Photographic Experts Group (JPEG), are simple and normally produces a residual sequence with lower zero-order entropy. Occasionally the entropy of the prediction error becomes greater than that of the original image. Such situations frequently occur when the image data have discrete gray levels located within certain intervals. To alleviate this problem, various authors have suggested different preprocessing methods. However, the techniques reported require two passes. We extend the definition of Lehmer-type inversions (Lehmer 1960 and 1964) from permutations to multiset permutations and present a one-pass algorithm based on inversions of a ...


Arts, Computers And Artificial Intelligence, Sol Neeman Ph.D. Nov 1996

Arts, Computers And Artificial Intelligence, Sol Neeman Ph.D.

Engineering Studies Faculty Publications and Creative Works

Science and art seem to belong to different cultures. Science and technology, mainly the products of the intellect, use terminology and vocabulary that are concise and well defined. In contrast, in artistic expression, ambiguity is a powerful component. Still the relationship between these two different categories of human activity is interesting and fascinating. In this paper, a general comparison of these two disciplines will be introduced. Then the possibility of mechanical creation of art using computers and artificial intelligence will be discussed. This will be followed by two techniques which are used to create poetry and music. First, a statistical ...


Remotely Possible? Simple Remote Access To The Network, Margaret Sylvia Nov 1996

Remotely Possible? Simple Remote Access To The Network, Margaret Sylvia

Faculty Publications

Remote access to the library is possible without a magic wand. we have seen increased use of the library in recent years, either because of, or despite, the possibility of remote access. One reason may be that some full-text material is still only available inside the library. Remote access was first implemented in the St. Mary's University Academic Library in 1991, shortly after the installation of the first network in the library. Various options for remote access are compared and contrasted, including the EA/2 solution.


Multimedia Applications Require Adaptive Cpu Scheduling, Veronica Baiceanu, Crispin Cowan, Dylan Mcnamee, Calton Pu, Jonathan Walpole Nov 1996

Multimedia Applications Require Adaptive Cpu Scheduling, Veronica Baiceanu, Crispin Cowan, Dylan Mcnamee, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

CPU scheduling and admission testing for multimedia applications have been extensively studied, and various solutions have been proposed using assorted simplifying assumptions. However, we believe that the complexity and dynamic behavior of multimedia applications and systems make static solutions hard to apply in real-world situations. We are analyzing the difficulties that arise when applying the rate-monotonic (RM) scheduling algorithm and the corresponding admission tests for CPU management, in the context of real multimedia applications running on real systems. RM requires statically predictable, periodic workloads, and while multimedia applications appear to be periodic, in practice they exhibit numerous variabilities in workload ...


Remotely Possible? Simple Remote Access To The Network, Margaret Sylvia Oct 1996

Remotely Possible? Simple Remote Access To The Network, Margaret Sylvia

Margaret Sylvia

Remote access to the library is possible without a magic wand. we have seen increased use of the library in recent years, either because of, or despite, the possibility of remote access. One reason may be that some full-text material is still only available inside the library. Remote access was first implemented in the St. Mary's University Academic Library in 1991, shortly after the installation of the first network in the library. Various options for remote access are compared and contrasted, including the EA/2 solution.


An Empirical Comparison Of Networks And Routing Strategies For Parallel Computation, Ronald I. Greenberg, Lee Guan Oct 1996

An Empirical Comparison Of Networks And Routing Strategies For Parallel Computation, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

This paper compares message routing capabilities of important networks proposed for general-purpose parallel computing. All the networks have been proven to have some type of universality property, i.e., an ability to simulate other networks of comparable cost with modest slowdown, using appropriate cost and communication models. But in this paper we seek an empirical comparison of communication capability under typical direct use rather than an analysis of worst-case results for simulating message traffic of another network.


A Theory Of Specification-Based Testing For Object-Oriented Software, StéPhane Barbey, Cécile Péraire, Didier Buchs Sep 1996

A Theory Of Specification-Based Testing For Object-Oriented Software, StéPhane Barbey, Cécile Péraire, Didier Buchs

Cécile Péraire

No abstract provided.


Issues And Theory For Unit Testing Of Object-Oriented Software, StéPhane Barbey, Didier Buchs, Cécile Péraire Sep 1996

Issues And Theory For Unit Testing Of Object-Oriented Software, StéPhane Barbey, Didier Buchs, Cécile Péraire

Cécile Péraire

No abstract provided.


Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon Sep 1996

Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon

Electrical Engineering & Computer Science Faculty Publications

This paper presents a new method for the planning of robot trajectories. The method presented assumes that joint-space knots have been generated from Cartesian knots by an inverse kinematics algorithm. The method is based on the globally optimal periodic interpolation scheme derived by Schoenberg, and thus is particularly suited for periodic robot motions. Of all possible periodic joint trajectories which pass through a specified set of knots, the trajectory derived in this paper is the ‘best’. The performance criterion used is the integral (over one period) of a combination of the square of the joint velocity and the square of ...


An Empirical Comparison Of Area-Universal And Other Parallel Computing Networks, Ronald I. Greenberg, Lee Guan Sep 1996

An Empirical Comparison Of Area-Universal And Other Parallel Computing Networks, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

This paper provides empirical comparison of the communication capabilities of two area-universal networks, the fat-tree and the fat-pyramid, to the popular mesh and hypercube networks for parallel computation. While area-universal networks have been proven capable of simulating, with modest slowdown, any computation of any other network of comparable area, prior work has generally left open the question of how area-universal networks compare to other networks in practice. Comparisons are performed using techniques of throughput and latency analysis that have previously been applied to k-ary n-cube networks and using various existing models to equate the hardware cost of the networks being ...


Unified Process Specification Language: Requirements For Modeling Process, Craig Schlenoff, Amy Knutilla, Steven Ray Aug 1996

Unified Process Specification Language: Requirements For Modeling Process, Craig Schlenoff, Amy Knutilla, Steven Ray

Steven R Ray

A wide range of applications deal with the manipulation and expression of collections of activities. Examples include project management, workflow management, business process reengineering, product realization process modeling, manufacturing process planning, production scheduling, simulation, and Computer Aided Software Engineering, each of which is supported by some combination of graphical programming and control languages, Petri nets, PERT charts or other representation methodology. Each of these applications serves a specific audience and need, and focuses on particular aspects of a process. Nevertheless, much could be gained by sharing information among applications. One of the primary obstacles to such integration is the lack ...


Concept Hierarchy Memory Model: A Neural Architecture For Conceptual Knowledge Representation, Learning, And Commonsense Reasoning, Ah-Hwee Tan, Hui-Shin Vivien Soon Jul 1996

Concept Hierarchy Memory Model: A Neural Architecture For Conceptual Knowledge Representation, Learning, And Commonsense Reasoning, Ah-Hwee Tan, Hui-Shin Vivien Soon

Research Collection School Of Information Systems

This article introduces a neural network based cognitive architecture termed Concept Hierarchy Memory Model (CHMM) for conceptual knowledge representation and commonsense reasoning. CHMM is composed of two subnetworks: a Concept Formation Network (CFN), that acquires concepts based on their sensory representations; and a Concept Hierarchy Network (CHN), that encodes hierarchical relationships between concepts. Based on Adaptive Resonance Associative Map (ARAM), a supervised Adaptive Resonance Theory (ART) model, CHMM provides a systematic treatment for concept formation and organization of a concept hierarchy. Specifically, a concept can be learned by sampling activities across multiple sensory fields. By chunking relations between concepts as ...


Genetic Algorithms Vs. Simulated Annealing: A Comparison Of Approaches For Solving The Circuit Partitioning Problem, Theodore W. Manikas, James T. Cain May 1996

Genetic Algorithms Vs. Simulated Annealing: A Comparison Of Approaches For Solving The Circuit Partitioning Problem, Theodore W. Manikas, James T. Cain

Computer Science and Engineering Research

An important stage in circuit design is placement, where components are assigned to physical locations on a chip. A popular contemporary approach for placement is the use of simulated annealing. While this approach has been shown to produce good placement solutions, recent work in genetic algorithms has produced promising results. The purpose of this study is to determine which approach will result in better placement solutions.

A simplified model of the placement problem, circuit partitioning, was tested on three circuits with both a genetic algorithm and a simulated annealing algorithm. When compared with simulated annealing, the genetic algorithm was found ...


Ua3/8/5 Application For Cause Award For Excellence In Campus Networking, Wku President's Office-Meredith Mar 1996

Ua3/8/5 Application For Cause Award For Excellence In Campus Networking, Wku President's Office-Meredith

WKU Archives Records

Application for CAUSE award for excellence in campus networking gives details about the first WKU computer network.


Development Of A Security Network (Secnet) Based On Integrated Services Digital Network (Isdn), Isidro Alvarez Mar 1996

Development Of A Security Network (Secnet) Based On Integrated Services Digital Network (Isdn), Isidro Alvarez

FIU Electronic Theses and Dissertations

The progress in the computing and communication industries together with the fast evolution of the semiconductor industry has made possible advances in the communications field. These advances have been used by other related applications to improve the services that they bring about. On the other hand, business crimes have increased three digits orders of magnitude in one decade, making from 20% to 30% of small businesses fail. These conditions demand new solutions to make security systems more reliable and efficient.

The present work combines ISDN as a network with a security system to create a security network (SECNET). It will ...


An Architecture Of Component - Based Capp Systems For Agile Manufacturing, Chun Zhang, Shaw Feng, Steven Ray Jan 1996

An Architecture Of Component - Based Capp Systems For Agile Manufacturing, Chun Zhang, Shaw Feng, Steven Ray

Steven R Ray

The current manufacturing planning software systems (such as computer aided process planning (CAPP) systems) are general and in a closed form, i.e., it is very difficult to modify these systems to respond to a user's dynamically changing needs. These systems are no longer suitable for agile manufacturing. This research work aims at developing an architecture for rapid development of CAPP systems. The architecture supports the construction of CAPP systems from prepackaged, plug-compatible software components. The specifications of the architecture and its building blocks are defined. A prototype system is under development to prove the concept.


Incorporating Matlab's Signal Processing Toolbox Into A Dsp Course At An Undergraduate E.E. Program, Sol Neeman Ph.D. Jan 1996

Incorporating Matlab's Signal Processing Toolbox Into A Dsp Course At An Undergraduate E.E. Program, Sol Neeman Ph.D.

Engineering Studies Faculty Publications and Creative Works

This paper provides some suggestions for incorporating MATLAB's Signal Processing Toolbox into a DSP course. Often, in a DSP course, students have difficulties understanding abstract and non-intuitive concepts and seeing their relevance to the practical part of their curriculum. The tools offered by MATLAB's Signal Processing Toolbox, can help to make these concepts more tangible and provide a perspective for students. Some basic tools relevant to an undergraduate DSP course will be introduced, including examples of tool use and graphic results. The tools presented will be applied in the areas of synthesis and analysis of signals, FFT computation ...


Power Spectra Of Signal Formats For Ds-Ss Cdma Wireless Lans, Beata J. Wysocki, Tadeusz Wysocki Jan 1996

Power Spectra Of Signal Formats For Ds-Ss Cdma Wireless Lans, Beata J. Wysocki, Tadeusz Wysocki

Faculty Publications in Computer & Electronics Engineering (to 2015)

The paper deals with the spectral analysis of signal formats for DS-SS CDMA WLANs. The main emphasis is put on introduction of a quantitative measure which allows for comparison of different spreading codes and channel modulations from the viewpoint of a uniformity of an in-hand power distribution Such a measure is essential to compare different DS-SS CDMA systems performance in mitigating the effects of frequency selective fading.


Performance Characteristics Of The Is-95 Standard For Cdma Spread Spectrum Mobile Communication Systems, Vijayalakshmi R. Raveendran Jan 1996

Performance Characteristics Of The Is-95 Standard For Cdma Spread Spectrum Mobile Communication Systems, Vijayalakshmi R. Raveendran

Retrospective Theses and Dissertations

No abstract provided.


An Optimistic Concurrency Control Mechanism Based On Clock Synchronization, Myoung Jin Park Jan 1996

An Optimistic Concurrency Control Mechanism Based On Clock Synchronization, Myoung Jin Park

Theses Digitization Project

No abstract provided.


On The Performance Of Early Packet Discard, Maurizio Casoni, Jonathan S. Turner Jan 1996

On The Performance Of Early Packet Discard, Maurizio Casoni, Jonathan S. Turner

All Computer Science and Engineering Research

In a previous paper [3], one of the authors, gave a worst-case analysis for the Early Packet Discard (EPD) technique for maintaining packet integrity during overload in ATM switches. This analysis showed that to ensure 100% goodput during overload under worst-case conditions, requires a buffer with enough storage for one maximum length packet from every active virtual circuit. This paper refines that analysis, using assumptions that are closer to what we expect to see in practice and examines how EPD performs when the buffer is not large enough to achieve 100% goodput. We show that 100% goodput can be achieved ...


Software Quality: Definitions And Strategic Issues, Ronan Fitzpatrick Jan 1996

Software Quality: Definitions And Strategic Issues, Ronan Fitzpatrick

Reports

This paper contains two sections relating to software quality issues. First, the various definitions of software quality are examined and an alternative suggested. It continues with a review of the quality model as defined by McCall, Richards and Walters in 1977 and mentions the later model of Boëhm published in 1978. Each of McCall's quality factors is reviewed and the extent to which they still apply in the late 1990s is commented on. The factors include, integrity, reliability, usability, accuracy, efficiency, maintainability, testability, flexibility,interface facility (interoperability), re-usability and transferability (portability). They are subdivided into external and internal quality ...


Translation Of 'Profiles In Faith', Monish Ranjan Chatterjee Jan 1996

Translation Of 'Profiles In Faith', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

Sarat Chandra Chatterjee (1876-1938) may be considered one of the three most significant figures of the literary component of the Bengal Renaissance, the other two being Bankim Chandra Chatterjee (1838-1894) and Rabindranath Tagore (1861-1941). As much as Bankim Chandra is identified with the new age in the Bengali novel, and the development of serious vernacular journalism, and Rabindranath with modern/classical movements in Bengali poetry and music, along with novel ideas in methods of education and teaching, Sarat Chandra, as a novelist and storyteller, perfected the art of narration and critical analyses of a variety of contemporaneous social and political ...


Design And Implementation Of A Practical Security-Conscious Electronic Polling System, Lorrie Faith Cranor, Ron K. Cytron Jan 1996

Design And Implementation Of A Practical Security-Conscious Electronic Polling System, Lorrie Faith Cranor, Ron K. Cytron

All Computer Science and Engineering Research

We present the design and implementation of Sensus, a practical, secure and private system for conducting surveys and elections over computer networks. Expanding on the work of Fujioka, Okamoto, and Ohta, Sensus uses blind signatures to ensure that only registered voters can vote and that each registered voter only votes once, while at the same time maintaining voters' privacy. Sensus allows voters to verify independently that their votes were counted correctly, and anonymously challenge the results should their votes be miscounted. We outline seven desirable properties of voting systems and show that Sensus satisfied these properties well, in some cases ...


Design Of Nonblocking Atm Networks, J. Andrew Fingerhut, Rob Jackson, Subhash Suri, Jonathan S. Turner Jan 1996

Design Of Nonblocking Atm Networks, J. Andrew Fingerhut, Rob Jackson, Subhash Suri, Jonathan S. Turner

All Computer Science and Engineering Research

This paper considers the problem of designing ATM networks that are nonblocking with respect to virtual circuit requests, subject to specified constraints on the traffic. In this paper, we focus on global traffic constraints that simply limit the total entering and exiting traffic at each switching system. After reviewing prior results for linear link costs, we introduce a more realistic link cost model, and develop a number of results using it. We also describe a technique for converting tree-structured networks to nonblocking hierarchical networks satisfying limits on the capacity of any single switch.