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Computer Engineering Commons

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1996

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Articles 1 - 30 of 61

Full-Text Articles in Computer Engineering

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.


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.


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 ...


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 ...


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 ...


Compile-Time Performance Prediction Of Hpf/Fortran 90d, Manish Parashar, Salim Hariri Jan 1996

Compile-Time Performance Prediction Of Hpf/Fortran 90d, Manish Parashar, Salim Hariri

Electrical Engineering and Computer Science

In this paper we present an interpretive approach for accurate and cost-effective performance prediction in a high performance computing environment, and describe the design of a compile-time HPF/Fortran 90D performance prediction framework based on this approach. The performance prediction framework has been implemented as a part of the HPF/Fortran 90D application development environment that integrates it with a HPF/Fortran 90D compiler and a functional interpreter. The current implementation of the environment framework is targeted to the iPSC/860 hypercube multicomputer system. A set of benchmarking kernels and application codes have been used to validate the accuracy, utility ...


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 ...


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 ...


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 ...


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.


A Framework For Integrated Communication And I/O Placement, Rajesh Bordawekar, Alok Choudhary, J Ramanujam Jan 1996

A Framework For Integrated Communication And I/O Placement, Rajesh Bordawekar, Alok Choudhary, J Ramanujam

Electrical Engineering and Computer Science

This paper describes a framework for analyzing dataflow within an out-of-core parallel program. Dataflow properties of FORALL statement are analyzed and a unified I/O and communication placement framework is presented. This placement framework can be applied to many problems, which include eliminating redundant I/O incurred in communication. The framework is validated by applying it for optimizing I/O and communication in out-of-core stencil problems. Experimental performance results on an Intel Paragon show significant reduction in I/O and communication overhead.


A Framework For Integrated Communication And I/O Placement, Rajesh Bordawekar, Alok Choudhary, J Ramanujam Jan 1996

A Framework For Integrated Communication And I/O Placement, Rajesh Bordawekar, Alok Choudhary, J Ramanujam

Electrical Engineering and Computer Science

This paper describes a framework for analyzing dataflow within an out-of-core parallel program. Dataflow properties of FORALL statement are analyzed and a unified I/O and communication placement framework is presented. This placement framework can be applied to many problems, which include eliminating redundant I/O incurred in communication. The framework is validated by applying it for optimizing I/O and communication in out-of-core stencil problems. Experimental performance results on an Intel Paragon show significant reduction in I/O and communication overhead.


Collaborative Scientific Data Visualization, Byeongseob Ki, Scott Klasky Jan 1996

Collaborative Scientific Data Visualization, Byeongseob Ki, Scott Klasky

Northeast Parallel Architecture Center

We have designed a collaborative scientific visualization package that will aid researchers from distant, diverse locations to work together in developing scientific codes, providing them with a system to analyze their scientific data. We have utilized Java to develop this infrastructure. Two important areas which we have concentrated on developing are 1) a collaborative framework from which the scientific data is interpreted and utilized, and 2) a framework, which is customizable to the suit the needs of a particular task and/or scientific group.


Semantic Correlation Of Behavior For The Interoperability Of Heterogeneous Simulations, Christopher James Dean Jan 1996

Semantic Correlation Of Behavior For The Interoperability Of Heterogeneous Simulations, Christopher James Dean

Retrospective Theses and Dissertations

A desirable goal of military simulation training is to provide large scale or joint exercises to train personnel at higher echelons. To help meet this goal, many of the lower echelon combatants must consist of computer generated forces with some of these echelons composed of units from different simulations. The object of the research described is to correlate the behaviors of entities in different simulations so that they can interoperate with one another to support simulation training. Specific source behaviors can be translated to a form in terms of general behaviors which can then be correlated to any desired specific ...


Analysis Of Mpeg Compressed Video Traffic, Jerome R. Cox Jr., O. Matthew Beal Jan 1996

Analysis Of Mpeg Compressed Video Traffic, Jerome R. Cox Jr., O. Matthew Beal

All Computer Science and Engineering Research

This paper outlines a study of MPEG compressed video sequences and simulation of multiplexed video traffic in the ATM environment. A number of statistical characteristics including autocorrelation and variance of MPEG-1 compressed video sequences are used to characterize the 16 sample traces used in this study. From these measurements, a preliminary model is developed which utilizes basic measurements of the individual component video sequences to predict bandwidth requirements and cell loss of the multiplexed video traffic.


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.


Bringing Real-Time Scheduling Theory And Practice Closer For Multimedia Computing, R. Gopalakrishnan, Guru M. Parulkar Jan 1996

Bringing Real-Time Scheduling Theory And Practice Closer For Multimedia Computing, R. Gopalakrishnan, Guru M. Parulkar

All Computer Science and Engineering Research

This paper seeks to bridge the gap between theory and practice of real-time scheduling in the domain of multimedia computer systems. We show that scheduling algorithms that are good in theory, often have practical limitations. However when these algorithms are modified based on practical considerations, existing theoretical results cannot be used as they are. In this paper we motivate the need for new scheduling schemes for multimedia protocol processing, and demonstrate their real-time performance in our prototype implementation. We then explain the observed results by analysis and measurement. More specifically, we show that using strict preemption can introduce overheads in ...


Design Of A Gigabit Atm Switch, Tom Chaney, Andrew Fingerhut, Margaret Flucke, Jonathan S. Turner Jan 1996

Design Of A Gigabit Atm Switch, Tom Chaney, Andrew Fingerhut, Margaret Flucke, Jonathan S. Turner

All Computer Science and Engineering Research

This report describes the design and implementation of a gigabit ATM switching system supporting link rates from 150 Mb/s to 2.4 Gb/s, with a uniquely efficient multicast switch architecture that enables the construction of systems with essentially constant per port costs for configurations ranging from 8 to 4096 ports and system capacities approaching 1- Tb.s. The system design supports many-to-one and many-to-many forms of multicast, in addition to the usual one-to-many. It also provides multicast virtual paths, constant time configuration of multicast connections and an efficient packet-level discard method, that can achieve 100% link efficiencies, without ...


Mobile Unity: Reasoning And Specification In Mobile Computing, Gruia-Catalin Roman, Peter J. Mccann Jan 1996

Mobile Unity: Reasoning And Specification In Mobile Computing, Gruia-Catalin Roman, Peter J. Mccann

All Computer Science and Engineering Research

Mobile computing represents a major point of departure from the traditional distributed computing paradigm. The potentially very large number of independent computing units, a decoupled computing style, frequent disconnections, continuous position changes, and the location-dependent nature of the behavior and communication patterns present designers with unprecedented challenges in the areas of modularity and dependability. So far, the literature on mobile computing is dominated by concerns having to do with the development of protocols and services. This paper complements this perspective by considering the nature of the underlying formal models that will enable us to specify and reason about such computations ...


Reconsidering Fragmentation And Reassembly, Girish P. Chandranmenon, George Varghese Jan 1996

Reconsidering Fragmentation And Reassembly, Girish P. Chandranmenon, George Varghese

All Computer Science and Engineering Research

We reconsider several issues related to fragmentation and reassembly in IP. We first reconsider reassembly. We describe a simple expected case optimization that improves reassembly performance to 38 instructions per fragment if the fragments arrive in FIFO order (the same assumption made in header prediction) which has been implemented in the NetBSD kernel. Next, we introduce the new idea of Graceful Intermediate Reassembly (GIR), which is a generalization of the existing IP mechanisms of destination and hop-by-hop reassembly. In GIR, we coalesce the fragments at an intermediate router in order to use the largest sized packets on its outgoing interface ...


Leap Forward Virtual Clock: An O(Loglogn) Fair Queuing Scheme With Guaranteed Delays And Throughput Fairness, Subhash Suri, George Varghese, Girish P. Chandranmenon Jan 1996

Leap Forward Virtual Clock: An O(Loglogn) Fair Queuing Scheme With Guaranteed Delays And Throughput Fairness, Subhash Suri, George Varghese, Girish P. Chandranmenon

All Computer Science and Engineering Research

We describe an efficient fair queuing scheme, Leap Forward Virtual Clock, that provides end-to-end delay bounds almost identical to that of PGPS fair queuing, along with throughput fairness. Our scheme can be implemented with a worst-case time O(loglogN) per packet guaranteed delay and throughput fairness. As its name suggests, our scheme is based on Zhang's virtual clock. While the original virtual clock scheme does not achieve throughput fairness, we can modify it with a simple leap forward mechanism that keeps the server clock from lagging too far behind the packet tags. We prove that our scheme guarantees a ...


Efficient User Space Protocol Implementations With Qos Guarantees Using Real-Time Upcalls, R. Gopalakrishnan, Guru M. Parulkar Jan 1996

Efficient User Space Protocol Implementations With Qos Guarantees Using Real-Time Upcalls, R. Gopalakrishnan, Guru M. Parulkar

All Computer Science and Engineering Research

Real-time upcalls (RTUs) are an operating systems mechanism to provide quality-of-service (QoS) guarantees to network applications, and to efficiently implement protocols in user space with (QoS) guarantees. Traditionally, threads (and real-time extensions to threads) have been used to structure concurrent activities in user space protocol implementations. However, preemptive scheduling required for real-time threads leads to excessive context switching, and introduces the need for expensive concurrency control mechanisms such as locking. The RTU mechanism exploits the iterative nature of protocol processing to eliminate the need for locking, and reduce asynchronous preemption, while ensuring real-time operation. In addition to efficiency, eliminating the ...