Digital Commons Network^™

A Comparison Of Error Categorization Schemes For Use In Software System Safety Programs, Richard Escobedo, Jim Thomas

Theses and Dissertations

Software safety is becoming increasingly important in the development of DoD advanced weapon systems. To make software safer, hazard conditions must be avoided along with the errors that accompany them. The first step in identifying errors is classifying error data. The area of software error classification is not as advanced as other software development areas. The technical literature lacks examples of comprehensive taxonomies that can be applied to various computer software domains and applications. The predominant approach is to organize errors into categories particular to the program currently in work. The typical error scheme is made of narrow categories that …

Factors In Human-Computer Interface Design (A Pilot Study), Susan Stewart

Theses and Dissertations

The DoD has budgeted over $9.8 billion for 1995 for information technology, yet many government office workers let their existing systems sit idle. This thesis explores why these computers are sitting idle. This researcher's initial hypothesis was that certain features of the human-computer interface can positively or negatively affect efficiency, retention, and satisfaction level of workers. Although some research is being done in this area, interfaces continue to be of poor quality, especially in the DoD, where long procurement cycles, forced purchases, and limited budgets result in out-of-date software. Intuitively most programmers know the human-computer interface impacts on a person's …

The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz

Theses and Dissertations

The Air Force Institute of Technology (AFIT) has pursued research in virtual environments since 1988. This research expands the current capabilities of the AFIT Virtual Cockpit (VC) by increasing the realism of the cockpit environment and improving the pilot's command interface. Realism is improved creating console elements from texture maps and polygonal models; these elements include working dials, switches and circuit breakers. The pilot command interface is improved in part by adapting the AFIT Information Pod using a two-dimensional mouse input to the virtual three-dimensional environment. This immersive virtual environment is also improved by modifications to the Head Mounted Display …

Parallelization Of The 2d Roe Scheme On The Intel Paragon, John R. Graham Iii

Theses and Dissertations

This study presented a methodology for determining the general performance characteristics of a computational fluid dynamics (CFD) algorithm on the Intel Paragon. By performing a rigorous time complexity analysis of a parallel CFD algorithm, the general performance could be characterized before the code was actually parallelized. This was shown by implementing a serial version of the 2-D Roe Scheme on the Paragon. This explicit code was parallelized by the addition of generic yet efficient routines that decomposed the domain, automatically adjusted partition indices, and performed 2-D and 3-D buffer exchanges. Additionally, efficient global routines available for the Paragon were used …

Easy-Sim: A Visual Simulation System Software Architecture With An Ada 9x Application Framework, Jordan R. Kayloe

Theses and Dissertations

Software architectures increase productivity when used as the basis for developing applications in a problem domain. This thesis describes the creation of Easy-Sim, an object-oriented software architecture for visual simulation systems, and its corresponding implementation as an application framework in Ada 9X. The research built upon ObjectSim, an existing object-oriented simulation architecture implemented as a application framework. Both ObjectSim and Easy-Sim operate on Silicon Graphics platforms and use the IRIS Performer graphics programming library. Easy-Sim is implemented using version 1.83 of the GNAT compiler. The investigation for this thesis involved honing ObjectSim's design, implementing the improved result in both C++ …

Improving Intrusion Detection In Unix-Based Networks, David R. Landry

Theses and Dissertations

Computer security has not kept pace with the rapid growth of networked systems. Through its connection to the Internet, the Department of Defense is vulnerable to computer-based attacks. Current intrusion detection systems are still unproven, too complicated, or too costly for most system security officers to implement. The attack methods used by system intruders are known and can be represented as groups of commands called attack signatures. This thesis investigates methods for detecting intruders by monitoring command usage. Testing was conducted in both controlled and uncontrolled circumstances. With controlled testing, it was shown that 7 of the 11 signatures could …

Transportable Agents, Keith D. Kotay, David Kotz

Dartmouth Scholarship

As network information resources grow in size, it is often most efficient to process queries and updates at the site where the data is located. This processing can be accomplished by using a traditional client-server network interface, which constrains the client to the set of queries supported by the server, or requires the server to send all data to the client for processing. The former is inflexible; the latter is inefficient. Transportable agents, which support the movement of the client computation to the location of the remote resource, have the potential to be more flexible and more efficient. Transportable agents …

The Fat-Pyramid And Universal Parallel Computation Independent Of Wire Delay, Ronald I. Greenberg

Computer Science: Faculty Publications and Other Works

This paper shows that a fat-pyramid of area Θ(A) requires only O(log A) slowdown to simulate any competing network of area A under very general conditions. The result holds regardless of the processor size (amount of attached memory) and number of processors in the competing networks as long as the limitation on total area is met. Furthermore, the result is valid regardless of the relationship between wire length and wire delay. We especially focus on elimination of the common simplifying assumption that unit time suffices to traverse a wire regardless of its length, since the assumption becomes more and more …

Semantics Vs. Syntax Vs. Computations Machine Models For Type-2 Polynomial-Time Bounded Functionals (Preliminary Draft), James S. Royer

Electrical Engineering and Computer Science - Technical Reports

This paper investigates analogs of the Kreisel-Lacombe-Shoenfield Theorem in the context of the type-2 basic feasible functionals, a.k.a. the Mehlhorn-Cook class of type-2 polynomial-time functionals. We develop a direct, polynomial-time analog of effective operation, where the time bound on computations is modeled after Kapron and Cook's scheme for their basic polynomial-time functionals. We show that (i) if P = NP, these polynomial-time effective operations are strictly more powerful on R (the class of recursive functions) than the basic feasible functions, and (ii) there is an oracle relative to which these polynomial-time effective operations and the basic feasible functionals have the …

1.1, Yolanda Jones

E-lert

No abstract provided.

Multiprocessor Document Allocation: A Neural Network Approach, Abdulaziz Sultan Al-Sehibani, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

Electrical Engineering and Computer Science - Technical Reports

We consider the problem of distributing the documents to a given set of processors so that the load on each processor is as equal as possible and the amount of communication is as small as possible. This is an NP-Complete problem. We apply continuous as well as discrete Hopfield neural networks to obtain suboptimal solutions for the problem. These networks perform better than a genetic algorithm for this task proposed by Frieder et al. [4]; in particular, the continuous Hopfield network performs extremely well.

Disk-Directed I/O For Mimd Multiprocessors, David Kotz

Computer Science Technical Reports

Many scientific applications that run on today's multiprocessors are bottlenecked by their file I/O needs. Even if the multiprocessor is configured with sufficient I/O hardware, the file-system software often fails to provide the available bandwidth to the application. Although libraries and improved file-system interfaces can make a significant improvement, we believe that fundamental changes are needed in the file-server software. We propose a new technique, disk-directed I/O, that flips the usual relationship between server and client to allow the disks (actually, disk servers) to determine the flow of data for maximum performance. Our simulations show that tremendous performance gains are …

A Data-Parallel Programming Library For Education (Dapple), David Kotz

Computer Science Technical Reports

In the context of our overall goal to bring the concepts of parallel computing into the undergraduate curriculum, we set out to find a parallel-programming language for student use. To make it accessible to students at all levels, and to be independent of any particular hardware platform, we chose to design our own language, based on a data-parallel model and on C++. The result, DAPPLE, is a C++ class library designed to provide the illusion of a data-parallel programming language on conventional hardware and with conventional compilers. DAPPLE defines Vectors and Matrices as basic classes, with all the usual C++ …

Icdm: Integrated Cooperative Decision Making - In Practice, Leonard Myers, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Multi-agent systems provide an attractive architecture for the implementation of complex systems. Much of the research is focussed on complete automation of the decision making process as a means of duplicating human abilities for working with new problems and environments. There as also a need for systems that employ the human as an agent and rely on human abilities for common sense and deep thought. The CAD Research Center at Cal Poly and CDM Technologies have significant experience in building systems of the latter type that assist human users in solving complex problems in planning, design and economics. This experience …

Multimedia Authoring, Development Environments, And Digital Video Editing, Fillia Makedon, James W. Matthews, Charles B. Owen, Samuel A. Rebelsky

Dartmouth Scholarship

Multimedia systems integrate text, audio, video, graphics, and other media and allow them to be utilized in a combined and interactive manner. Using this exciting and rapidly developing technology, multimedia applications can provide extensive benefits in a variety of arenas, including research, education, medicine, and commerce. While there are many commercial multimedia development packages, the easy and fast creation of a useful, full-featured multimedia document is not yet a straightforward task.

This paper addresses issues in the development of multimedia documents, ranging from user-interface tools that manipulate multimedia documents to multimedia communication technologies such as compression, digital video editing and …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 9, November 1994, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A fourteen page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Covering Radius 1985-1994, G. D. Cohen, S. N. Litsyn, Antoine C. Lobstein, H. F. Mattson Jr

Electrical Engineering and Computer Science - Technical Reports

We survey important developments in the theory of covering radius during the period 1985-1994. We present lower bounds, constructions and upper bounds, the linear and nonlinear cases, density and asymptotic results, normality, specific classes of codes, covering radius and dual distance, tables, and open problems.

Distributed Scheduling In Finite Capacity Networks, Perry Fizzano, Clifford Stein

Computer Science Technical Reports

We consider the problem of scheduling unit-sized jobs in a distributed network of processors. Each processor only knows the number of jobs it and its neighbors have. We give an analysis of intuitive algorithm and prove that the algorithm produces schedules that are within a logarithmic factor of the length of the optimal schedule given that the optimal schedule is sufficiently long.

Building Multimedia Proceedings: The Roles Of Video In Interactive Electronic Conference Proceedings, Samuel A. Rebelsky, Fillia Makedon, James Matthews, Charles Owen, Laura Bright, Kenneth Harker, Nancy Toth

Computer Science Technical Reports

Modern computer systems have changed the way that conference proceedings can be presented and archived. No longer are researchers limited by printed text; electronic proceedings allow one to search the proceedings, add and share annotations, and create paths of related concepts through the proceedings. These additional capabilities extend the opportunities and benefit the thought processes of actual conference participants and the new virtual participants who experience the conference through the electronic proceedings.

In this paper, we discuss the construction of electronic conference proceedings, highlighting the role of talks and other presentations (and, particularly, the audio and video of these talks …

Incremental Equational Programming, Samuel A. Rebelsky

Computer Science Technical Reports

This paper extends Equational Programming (EP)—a declarative, symbolic programming language—to allow programs to manipulate incrementally defined and modified input terms and to avoid repeated work when evaluating these incremental terms. This paper represents two key aspects of this extension: a notation for representing revision and a modification to EP's runtime library to accomodate this notation. Unlike Field's method of incremental term rewriting, which is designed for more general but less efficient term-rewriting systems, this paper's method accomodates EP's restrictions (in particular, EP's decision to disallow overlapping rules) so that it may take advantage of EP's speed.

Characterization Of A Class Of Sigmoid Functions With Applications To Neural Networks, Anil Ravindran Menon, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

Electrical Engineering and Computer Science - Technical Reports

Sigmoid functions, whose graphs are "S-shaped" curves, appear in a great variety of contexts, such as the transfer functions in many neural networks. Their ubiquity is no accident; these curves are the among the simplest non-linear curves, striking a graceful balance between linear and non-linear behavior.

Disk-Directed I/O For Mimd Multiprocessors, David Kotz

Dartmouth Scholarship

Many scientific applications that run on today's multiprocessors are bottlenecked by their file I/O needs. Even if the multiprocessor is configured with sufficient I/O hardware, the file-system software often fails to provide the available bandwidth to the application. Although libraries and improved file-system interfaces can make a significant improvement, we believe that fundamental changes are needed in the file-server software. We propose a new technique, \em disk-directed I/O, that flips the usual relationship between server and client to allow the disks (actually, disk servers) to determine the flow of data for maximum performance. Our simulations show that tremendous performance gains …

Efficient Parallel Algorithms For Closest Point Problems, Peter Su

Dartmouth College Ph.D Dissertations

This dissertation develops and studies fast algorithms for solving closest point problems. Algorithms for such problems have applications in many areas including statistical classification, crystallography, data compression, and finite element analysis. In addition to a comprehensive empirical study of known sequential methods, I introduce new parallel algorithms for these problems that are both efficient and practical. I present a simple and flexible programming model for designing and analyzing parallel algorithms. Also, I describe fast parallel algorithms for nearest-neighbor searching and constructing Voronoi diagrams. Finally, I demonstrate that my algorithms actually obtain good performance on a wide variety of machine architectures. …

Design And Implementation Of Tools To Increase User Control And Knowledge Elicitation In A Virtual Battlespace, Jim J. Rohrer

Theses and Dissertations

AFIT's Synthetic BattleBridge is an immersive command observatory for viewing large-area activity within a virtual environment. Three basic areas for improvement are addressed: (1) an improved, immersive, user interface, (2) direct control of atmospheric effects, and (3) improved knowledge elicitation by means of remote viewers, a new space scope, and an enhanced RADAR scope. These requirements are analyzed and implemented. Some functionality was lost but the results show a general improvement of environmental control and knowledge elicitation.

Contour Ranking On Coarse Grained Machines: A Case Study For Low-Level Vision Computations, Farooq Hameed, Ashfaq A. Khokhar, Susanne E. Hambrusch, Jamshed Patel

Department of Computer Science Technical Reports

No abstract provided.

Locally Resolvable B-Reps, Carlos Gonzalez-Ochoa, George Vanecek

Department of Computer Science Technical Reports

No abstract provided.

Study Of Intrusion Of A Software Trace System In The Execution Of Parallel Programs, Kuei Yu Wang

Department of Computer Science Technical Reports

No abstract provided.

Problem Solving In Human Beings And Computers (Formerly: Heuristic Problem Solving), Zygmunt Pizlo, Anupam Joshi, Scott M. Graham

Department of Computer Science Technical Reports

No abstract provided.

Incremental Construction Of Multi-Dimen- Sional Space Partitioning Trees, George Vanecek, Shankara Shastry M.C.

Department of Computer Science Technical Reports

No abstract provided.

R-By-C Crozzle: An Np-Hard Problem, Michelle Gower, Ralph Wilkerson

Computer Science Technical Reports

In an Auslralian magazine, a monetary prize is awarded to the person with the best answer to a word puzzle called a Crozzle. Each valid placement of given words into a 10x 15 grid is given a score, and the best answer is the placement with the largest score. Various search techniques have been utilized lo solve this problem. No one has shown whether there is a polynomial-time algorithm to find the best Crozzle. This paper proves that the Crozzle is in NP. It also creates a similar word puzzle, called R-by-C Crozzle, by lifting the constraint on the grid …