Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Computer Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 28951 - 28980 of 29849

Full-Text Articles in Entire DC Network

Software Support For Irregular And Loosely Synchronous Problems, Alok Choudhary, Geoffrey C. Fox, Sanja Ranka, Seema Hiranandani Jan 1992

Software Support For Irregular And Loosely Synchronous Problems, Alok Choudhary, Geoffrey C. Fox, Sanja Ranka, Seema Hiranandani

Northeast Parallel Architecture Center

A large class of scientific and engineering applications may be classified as irregular and loosely synchronous from the perspective of parallel processing. We present a partial classification of such problems. This classification has motivated us to enhance Fortran D to provide language support for irregular, loosely synchronous problems. We present techniques for parallelization of such problems in the context of Fortran D.


Scheduling Regular And Irregular Communication Patterns On The Cm-5, Ravi Ponnusamy, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox Jan 1992

Scheduling Regular And Irregular Communication Patterns On The Cm-5, Ravi Ponnusamy, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox

Northeast Parallel Architecture Center

In this paper, we study the communication characteristics of the CM-5 and the performance effects of scheduling regular and irregular communication patterns on the CM-5. We consider the scheduling of regular communication patterns such as complete exchange and broadcast. We have implemented four algorithms for complete exchange and studied their performances on a 2D FFT algorithm. We have also implemented four algorithms for scheduling irregular communication patterns and studied their performance on the communication patterns of several synthetic as well as real problems such as the conjugate gradient solver and the Euler solver.


Which Applications Can Use High Performance Fortran And Fortran-D: Industry Standard Data Parallel Languages?, Alok Choudhary, Geoffrey C. Fox, Tomasz Haupt, S. Ranka Jan 1992

Which Applications Can Use High Performance Fortran And Fortran-D: Industry Standard Data Parallel Languages?, Alok Choudhary, Geoffrey C. Fox, Tomasz Haupt, S. Ranka

Northeast Parallel Architecture Center

In this paper, we present the first, preliminary results of HPF/Fortran-D language analysis based on compiling and running benchmark applications using a prototype implementation of HPF/Fortran-D compiler. The analysis indicate that the HPF is a very convenient tool for programming many applications on massively parallel and/or distributed systems. In addition, we cumulate experience on how to parallelize irregular problems to extend the scope of Fortran-D beyond HPF and suggest future extensions to the Fortran standard.


Compiling Distribution Directives In A Fortran 90d Compiler, Zeki Bozkus, Alok Choudhary, Geoffrey C. Fox, Sanjay Ranka Jan 1992

Compiling Distribution Directives In A Fortran 90d Compiler, Zeki Bozkus, Alok Choudhary, Geoffrey C. Fox, Sanjay Ranka

Northeast Parallel Architecture Center

Data Partitioning and mapping is one of the most important steps of in writing a parallel program; especially data parallel one. Recently, Fortran D, and subsequently, High Performance Fortran (HPF) have been proposed to allow users to specify data distributions and alignments for arrays in programs. This paper presents the design of a Fortran 90D compiler that takes a Fortran 90D program as input and produces a node program + message passing calls for distributed memory machines. Specifically, we present the design of the Data Partitioning Module that processes the alignment and distribution directives and illustrate what are the important …


A Comparison Of Text And Graphics As Effective User Interfaces In A Proposed Advanced Train Control System, Kenneth A. Organes Jan 1992

A Comparison Of Text And Graphics As Effective User Interfaces In A Proposed Advanced Train Control System, Kenneth A. Organes

UNF Graduate Theses and Dissertations

This study tested the effectiveness of three screen interface formats for use in a proposed on-board computer to be used as part of an advanced train control system. One of the three formats contained only graphic depictions of the data, one contained only textual representations and the third had a mixture of graphic and textual data.

Twenty-eight subjects with varying railroad experience were recruited for the experiment. They were divided into three groups, each of which was presented with a simulation using one of the three interface types. The simulations depicted possible engine, track and train conditions that might be …


Program Maintenance And Code Reuse: Object Oriented Versus Procedure Oriented Programming, Beiramali Moradi Jan 1992

Program Maintenance And Code Reuse: Object Oriented Versus Procedure Oriented Programming, Beiramali Moradi

Theses

The purpose of this thesis is to address the problem of the increasing cost of program maintenance in the data processing world. On average, programmers today spend 60% of their time in program maintenance and that figure is increasing at an estimated rate of 1 % each year. The cost is staggering and almost every business would like to find ways of reducing maintenance costs. One way to help reduce maintenance and development costs is to improve code reusability. Both maintenance programming and code reusability are the focus of this thesis.

Today's most commonly used programming language style is procedure …


Distributed Ray Casting For High-Speed Volume Rendering, Patricia L. Brightbill Jan 1992

Distributed Ray Casting For High-Speed Volume Rendering, Patricia L. Brightbill

Theses and Dissertations

The volume rendering technique known as ray casting or ray tracing is notoriously slow for large volume sizes, yet provides superior images. A technique is needed to accelerate ray tracing volumes without depending on special purpose or parallel computers. The realization and improvements in distributed computing over the past two decades has motivated its use in this work. This thesis explores a technique to speedup ray casting by distributed programming. The work investigates the possibility of dividing the volume among general purpose workstations and casting rays (using Levoy's front-to-back algorithm) through each subvolume independently. The final step being the composition …


System Design Quality And Efficiency Of System Analysts: An Automated Case Tool Versus A Manual Method, Satomi H. Sugishita Jan 1992

System Design Quality And Efficiency Of System Analysts: An Automated Case Tool Versus A Manual Method, Satomi H. Sugishita

UNF Graduate Theses and Dissertations

The purpose of the current research study is to find out if CASE tools help to increase the software design quality and efficiency of system analysts and designers when they modify a system design document. Results of the experimental data analysis show that only the experience level of subjects had an effect on quality of their work. Results indicated that the design methods, either CASE tools or manual, do not have a significant effect on quality of the modification task nor the efficiency of system analysts and designers.


The Group Spreadsheet, George Francis Morrissey Jr. Jan 1992

The Group Spreadsheet, George Francis Morrissey Jr.

UNF Graduate Theses and Dissertations

Groupware is fast becoming an important part of the computing world. This thesis reviews past history and research in which a group oriented spreadsheet is shown to have a real purpose in today's business world. A group oriented spreadsheet was implemented using a public domain package called The Spreadsheet Calculator. Spreadsheet users and programmers tested the implementation. The results and conclusions of this implementation are also presented.


A Universal Method Of Scientific Inquiry, Daniel N. Osherson, Michael Stob, Scott Weinstein Jan 1992

A Universal Method Of Scientific Inquiry, Daniel N. Osherson, Michael Stob, Scott Weinstein

University Faculty Publications and Creative Works

A paradigm of scientific discovery is defined within a first-order logical framework. Within this paradigm, the concept of “successful scientific inquiry” is formalized and investigated. Among other results, it is shown that a simple method of scientific inquiry is universal in the sense that it leads to success on every problem for which success is in principle possible.


Composite Stock Cutting Through Simulated Annealing, Hanan Lutfiyya, Bruce M. Mcmillin, Pipatpong Poshyanonda, Cihan H. Dagli Jan 1992

Composite Stock Cutting Through Simulated Annealing, Hanan Lutfiyya, Bruce M. Mcmillin, Pipatpong Poshyanonda, Cihan H. Dagli

Computer Science Faculty Research & Creative Works

This paper explores the use of Simulated Annealing as an optimization technique for the problem of Composite Material Stock Cutting. The shapes are not constrained to be convex polygons or even regular shapes. However, due to the composite nature of the material, the orientation of the shapes on the stock is restricted. For placements of various shapes, we show how to determine a cost function, annealing parameters and performance. © 1992.


Formation Of Clusters And Resolution Of Ordinal Attributes In Id3 Classification Trees, Chaman Sabharwal, Keith R. Hacke, Daniel C. St. Clair Jan 1992

Formation Of Clusters And Resolution Of Ordinal Attributes In Id3 Classification Trees, Chaman Sabharwal, Keith R. Hacke, Daniel C. St. Clair

Computer Science Faculty Research & Creative Works

Many learning systems have been designed to construct classification trees from a set of training examples. One of the most widely used approaches for constructing decision trees is the ID3 algorithm [Quinlan 1986]. Decision trees are ill-suited to handle attributes with ordinal values. Problems arise when a node representing an ordinal attribute has a branch for each value of the ordinal attribute in the training set. This is generally infeasible when the set of ordinal values is very large. Past approaches have sought to cluster large sets of ordinal values before the classification tree is constructed [Quinlan 1986; Lebowitz 1985; …


A Study Of The Methodologies Currently Available For The Maintenance Of The Knowledge-Base In An Expert System, Kai Teh Jan 1992

A Study Of The Methodologies Currently Available For The Maintenance Of The Knowledge-Base In An Expert System, Kai Teh

Theses: Doctorates and Masters

This research studies currently available maintenance methodologies for expert system knowledge bases and taxonomically classifies them according to the functions they perform. The classification falls into two broad categories. These are: (1) Methodologies for building a more maintainable expert system knowledge base. This section covers techniques applicable to the development phases. Software engineering approaches as well as other approaches are discussed. (2) Methodologies for maintaining an existing knowledge base. This section is concerned with the continued maintenance of an existing knowledge base. It is divided into three subsections. The first subsection discusses tools and techniques which aid the understanding of …


A Comparison Of The Effects Of Reading From A Vdu And From Paper As Measured In Terms Of Reading Speed And Comprehension, Elizabeth Payumo Jan 1992

A Comparison Of The Effects Of Reading From A Vdu And From Paper As Measured In Terms Of Reading Speed And Comprehension, Elizabeth Payumo

Theses: Doctorates and Masters

This study investigates the legibility and visual effects of eight combinations of font and colour on VDU and two different fonts on paper. Forty subjects, sixteen females and twenty-four males, were exposed to three of the ten different conditions, one in each of the set of readings, on either VDU or paper. They were asked to read different sets of stories in each condition on different days where each condition lasted for approximately two hours. Reading speed and comprehension scores were measured in every story read in the set of stories. The change of mood and physical symptoms states of …


Smimd - A Synchronous Multiple Instruction Multiple Data Computer Architecture, Cathy C. Roberts Jan 1992

Smimd - A Synchronous Multiple Instruction Multiple Data Computer Architecture, Cathy C. Roberts

Computer Science Theses & Dissertations

This thesis assesses the feasibility of utilizing a hypercube interconnect topology to link a heterogeneous processor array in a very long instruction word (VLIW) computer architecture. The research focused upon the selection of a suitable arrangement of processors for the computer and the subsequent demonstration of the architecture's capability to handle simple loop iterations. Previous attempts at VLIW computer design are summarized, the new SMIMD architecture is presented, and suggestions for future research are given. The thesis concludes with results of the initial performance evaluations of the architecture design.


The A.D.E. Taxonomy Of Spreadsheet Application Development, Maria Jean Hall Jan 1992

The A.D.E. Taxonomy Of Spreadsheet Application Development, Maria Jean Hall

Theses: Doctorates and Masters

Spreadsheets are a major application in end-user computing, one of the fastest growing areas of computing. Studies have shown that 30% of spreadsheet applications contain errors. As major decisions are often made with the assistance of spreadsheets, the control of spreadsheet applications is a matter of concern to enduser developers, managers, EDP auditors and computer professionals.

The application of appropriate controls to the spreadsheet development process requires prior categorisation of the spreadsheet application. The special-purpose A.D.E. (Application, Development, Environment) taxonomy of spreadsheet application development was evolved by mathematical taxonomic methods to categorise spreadsheet development projects to facilitate their management and …


An Investigation Of Ibm Pc Computer Viruses Infection Rates And Types In A Western Australian Environment, Boon Guan Lee Jan 1992

An Investigation Of Ibm Pc Computer Viruses Infection Rates And Types In A Western Australian Environment, Boon Guan Lee

Theses : Honours

In recent years computer viruses have become increasingly significant as a form of computer abuse. By virtue of their reproductive capability, computer viruses can have cumulative and potentially catastrophic effects to the many people who use those affected computers. There is a growing concern in the computing community about these forms of electronic vandalism. This concern arises from the possible damage to stored information on which the work depends and the ensuing disruption of the work-place. Although the vandalism or purposeful abuse by introducing computer viruses to computer systems was originally mainly an American experience, research reports published by the …


Application Of Expert System Techniques For Award Implementation, Seng-Choon Yeoh Jan 1992

Application Of Expert System Techniques For Award Implementation, Seng-Choon Yeoh

Theses : Honours

This paper describes a pilot expert system project, PESWEA, developed in conjunction with The Western Australian Government Railways Commission (Westrail), to locate and implement an expert system pilot solution to the problems and complexities of the awards. The paper will outline the process used to develop and implement a solution to a business requirement. In particular, the methodologies for the project, shell selection, and knowledge acquisition will be presented and discussed. The fundamentals of expert systems will be discussed to provide the reader an insight into the technology. In addition, this paper reviews the literature relevant to the research questions. …


Porting The Chorus Supervisor And Related Low-Level Functions To The Pa-Risc, Ravi Konuru, Marion Hakanson, Jon Inouye, Jonathan Walpole Jan 1992

Porting The Chorus Supervisor And Related Low-Level Functions To The Pa-Risc, Ravi Konuru, Marion Hakanson, Jon Inouye, Jonathan Walpole

Computer Science Faculty Publications and Presentations

This document is part of a series of reports describing the design decisions made in porting the Chorus Operating System to the Hewlett-Packard 9000 Series 800 workstation.

The Supervisor is the name given by Chorus to a collection of low-level functions that are machine dependent and have to be implemented when Chorus is ported from one machine to another. The Supervisor is responsible for interrupt, trap and exception handling, managing low-level thread initialization, context switch, kernel initialization, managing simple devices (timer and console) and offering a low-level debugger. This document describes the port of the Supervisor and related low-level functions. …


Porting Chorus To The Pa-Risc: Building, Debugging, Testing And Validation, Ravi Konuru, Marion Hakanson, Jon Inouye, Jonathan Walpole Jan 1992

Porting Chorus To The Pa-Risc: Building, Debugging, Testing And Validation, Ravi Konuru, Marion Hakanson, Jon Inouye, Jonathan Walpole

Computer Science Faculty Publications and Presentations

This document is part of a series of reports describing the design decisions made in porting the Chorus Operating System to the Hewlett-Packard 9000 Series 800 workstation. This document describes the environment for building the Chorus kernel, the various kernel tests, and the debugging environment used for porting the Chorus operating system to the HP PA-RISC.

The information contained in this paper will be of interest to people who wish to:

• Use the PA-Chorus kernel for development and/or modification, • Know about the build environment for Chorus kernel on PA-RISC, • Know about the PA-Chorus approach to debugging, • …


Editing Digital Audio Using A Perceptual Model, J. Mark Goode Dec 1991

Editing Digital Audio Using A Perceptual Model, J. Mark Goode

Theses

In this paper we describe an intelligent system used to aid an audio recording producer in the selection of edit points in a musical sequence. It is possible to make meaningful recommendations concerning auditory input data without the ability to fully classify that data or interpret all outside goals. Perceptual modeling of the auditory input can allow sufficient reasoning ability for an intelligent system to be of use editing digital audio. To create a perceptual model, the information which can be extracted by the ear is embodied in several expert sections which communicate with a rule based decision maker via …


Communications Network For Distributed Real-Time Systems, Charles Silva Dec 1991

Communications Network For Distributed Real-Time Systems, Charles Silva

Theses

No abstract provided.


Unix And Security: The Influences Of History, Eugene H. Spafford Dec 1991

Unix And Security: The Influences Of History, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.


Three Letters On Computer Security And Society, Eugene H. Spafford Dec 1991

Three Letters On Computer Security And Society, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.


A Study In Systems Integration Architecture, Sashidhar M. Prasad Dec 1991

A Study In Systems Integration Architecture, Sashidhar M. Prasad

Theses

This Thesis studies the two architectures OSCA and ANSA which support the ODPSE principle in the first two parts. In the third part the framework for integrating these two architectures is described. The idea of integration architectures in relation to open architectures is studied using the enabling technologies.


User Authentication And Related Topics: An Annotated Bibliography, Eugene H. Spafford, Stephen A. Weeber Dec 1991

User Authentication And Related Topics: An Annotated Bibliography, Eugene H. Spafford, Stephen A. Weeber

Department of Computer Science Technical Reports

No abstract provided.


A Note On Many-One And 1-Truth-Table Complete Languages, Steven Homer, Stuart A. Kurtz, James S. Royer Dec 1991

A Note On Many-One And 1-Truth-Table Complete Languages, Steven Homer, Stuart A. Kurtz, James S. Royer

Electrical Engineering and Computer Science - Technical Reports

The polynomial time 1-tt complete sets for EXP and RE are polynomial time many-one complete.


Migrating A C-Based Cad Tool To An Object-Oriented Database/C++ Environment: Conversion Costs And Performance Analysis, Mark A. Roth, Timothy M. Jacobs Dec 1991

Migrating A C-Based Cad Tool To An Object-Oriented Database/C++ Environment: Conversion Costs And Performance Analysis, Mark A. Roth, Timothy M. Jacobs

AFIT Documents

his paper examines the potential of object-oriented databases to support complex design applications. To do this we migrated the Magic very large scale integrated (VLSI) circuit design tool written in the C language to a new environment in which Magic's existing file management code is replaced with a C++ language interface to the commercial object-oriented database management system (OODBMS) product Object Store. In our initial implementation we found the performance of this tool as implemented on the OODBMS to be marginally faster than the tool as currently implemented with a flat file system in several critical areas. Increased functionality, including …


Ccis Networking - December 1991, Nova University Dec 1991

Ccis Networking - December 1991, Nova University

CCIS Networking / SCIS Networking magazines

No abstract provided.


Parallel Divide And Conquer, Per Brinch Hansen Dec 1991

Parallel Divide And Conquer, Per Brinch Hansen

Electrical Engineering and Computer Science - Technical Reports

We develop a generic divide and conquer algorithm for a parallel tree machine. From the generic algorithm we derive balanced, parallel versions of quicksort and the fast Fourier transform by substitution of data types, variables and statements. The performance of these algorithms is analyzed and measured on a Computing Surface configured as a tree machine with distributed memory.