Engineering Commons^™

Object-Oriented Analysis, Design, And Implementation Of The Saber Wargame, David S. Douglass

Theses and Dissertations

Saber is a two-sided, air and land war game that simulates decisions made of commanders at the theater-level. It is being developed by the Air Force Institute of Technology for the Air Force Wargaming center at Maxwell AFB, Alabama. Saber models conventional, chemical, and nuclear warfare between aggregated air and land forces. It also portrays the effects of logistics, satellites, weather, terrain, and intelligence which add to the realism of the Saber war game. The Saber war game has three main components, the preprocessor. which is responsible for scenario development and pregame activities, the simulation. the guts of the war …

An Investigation Of Structural Locality In The Memory Referencing Behavior Of Computer Programs, Michael E. Bletzinger

Theses and Dissertations

The nature of structural locality as defined by same stack distance access is investigated in this thesis. The question is whether structural locality can be characterized as an inherent type of behavior. The results revealed that structural locality is strongly influenced by a program's design and phase of execution. Entropy measurements revealed that the predictiveness of structural locality is also influenced by program design. A Markov model was refined to capture the characteristics of structural locality that were measured. Trace synthesis demonstrated some success in reproducing same stack distance run distributions when the model had enough states to encompass the …

An Intelligent Real-Time System Architecture Implemented In Ada, Michael A. Whelan

Theses and Dissertations

Conventional real-time systems are fully deterministic allowing for off-line, optimal, task scheduling under all circumstances. Real-time intelligent systems add non-deterministic task execution times and non- deterministic task sets for scheduling purposes. Non-deterministic task sets force intelligent real-time systems to trade-off execution time with solution quality during run-time and perform dynamic task scheduling. Four basic design considerations addressing those tradeoffs have been identified: control reasoning, focus of attention, parallelism, and algorithm efficacy. Non-real- time intelligent systems contain an environment sensor, a model of the environment, a reasoning process, and a large collection of procedural processes. Real-time intelligent systems add to these …

Satcom General Purpose Modem Dscs Iii Sct Beacon Telemetry Display, James D. Coppola

Theses and Dissertations

This thesis documents the design and implementation of a DSCS III single Channel Transponder (SCT) beacon telemetry display. The system is a personal computer based design which interfaces to three SCT beacon receiver/demodulators. The software was designed to decode and display both the DSCS III A and DSCS HI B satellite beacons. Recordings of the SCT beacon display can be made on paper and/or magnetic media when triggered by the user, a watchdog timer, or the SCT command accept telemetry bit. In addition, the system can be configured with an IRIG B Universal Time Coordinates (UTC) card which enables the …

Parallel Simulation Of Structural Vhdl Circuits On Intel Hypercubes, Thomas A. Breeden

Theses and Dissertations

Many VLSI circuit designs are too large to be simulated with VHDL in a reasonable amount of time. One approach to reducing the simulation time is to distribute the simulation over several processors. This research creates an environment for designing and simulating structural VHDL circuits on the Intel iPSC/2 and iPSC/860 Hypercubes. Logic gates and system behaviors are partitioned among the processors, and signed changes are shared via event messages. Circuit simulations are run over the SPECTRUM parallel simulation testbed, and the null- message paradigm is used to avoid deadlock. Structural circuits ranging from forty to over one thousand logic …

Development Of A Protocol Usage Guideline For Conservative Parallel Simulations, Prescott J. Van Horn

Theses and Dissertations

The objective of distributed simulation is to speedup simulation execution by partitioning the simulation processing load over multiple processors, This thesis reviews current synchronization protocol methods for distributed simulations, and proposes guidelines for obtaining optimal conservative simulation partitionings using empirical evidence. An analysis is performed using three protocol variations of the Chandy-Misra HULL message algorithm, two using a pending message blocking strategy, and the other using a safetime blocking strategy. A fourth protocol evaluated is based on the SRADS algorithm proposed by Reynolds. The analysis involves a study of all possible 2 and 4 node configurations, for three queuing simulations, …

Solution To A Multicriteria Aircraft Routing Problem Utilizing Parallel Search Techniques, James J. Grimm Iii

Theses and Dissertations

Pilots select routes based on factors such as threats, fuel, time on target, distance, and refueling points. This is a time consuming task. This thesis presents the software engineering synthesis of a software tool, based on a parallelized A* search algorithm, to select routes. For simplicity only threats and distance are used. A centralized open list is used with one processor managing the list while the other processors perform the node expansions. This decomposition result in a dynamically load balanced system. A number of parameters are changed to study their impact on the execution time. The use of a branch …

Computer Simulation Of A General Purpose Satellite Modem, William L. Montgomery Jr.

Theses and Dissertations

The purpose of this research was to model and simulate the performance of a digital phase shift keyed satellite modem. The probability of bit error (P sub b) at different levels of energy per bit to noise power ratio (E sub b/N sub o) was the performance measure. The channel was assumed to contribute only additive white Gaussian noise. A second order Costas loop performs demodulation in the modem and was the key part of the simulation. The Costas loop with second order Butterworth arm filters was tested by finding the response to a phase or frequency step. The Costas …

A Vhdl Interpreter For Model-Based Diagnoses, David R. Griffin

Theses and Dissertations

Model-based reasoning permits diagnostic applications to be written without waiting for someone to become an 'expert' of the system. For model-based diagnostics, there must be a model to reason from. This thesis explores using a VHDL description of the system as that model. A system based around a VHDL interpreter was written specifically for a model-based diagnostic algorithm. Currently, the diagnostic system uses an algorithm by Dries. This algorithm was derived from Scarl's Full Consistency Algorithm. The system was designed to be modular so that different diagnostic techniques could be implemented. It is divided into three parts: a VHDL parser, …

Design And Development Of A High-Speed Winograd Fast Fourier Transform Processor Board, James F. Herron

Theses and Dissertations

Since 1985, the Air Force Institute of Technology has pursued a project to develop a 4080-point Discrete Fourier Transform processor using the Winograd Fourier Transform Algorithm (WFTA) and Good-Thomas Prime Factoring Algorithm (PFA). In the first attempt to build a working system, this research effort designed and constructed, in part, a modified single processor architecture in order to demonstrate the proof of concept of the WFTA system design. This prototype architecture is simpler in implementation but uses the same principles and procedures as those of the 4080-point WFTA design. The design developed in this thesis was validated using the Very …

Generalization And Parallelization Of Messy Genetic Algorithms And Communication In Parallel Genetic Algorithms, Laurence D. Merkle

Theses and Dissertations

Genetic algorithms (GA) are highly parallelizable, robust semi- optimization algorithms of polynomial complexity. The most commonly implemented GAs are 'simple' GAs (SGAs). Reproduction, crossover, and mutation operate on solution populations. Deceptive and GA-hard problems are provably difficult for simple GAs. Messy GAs (MGA) are designed to overcome these limitations. The MGA is generalized to solve permutation type optimization problems. Its performance is compared to another MGA's, an SGA's, and a permutation SGA's. Against a fully deceptive problem the generalized MGA (GMGA) consistently performs better than the simple GA. Against an NP-complete permutation problem, the GMGA performs better than the other …

Formalizing, Validating, And Verifying Real-Time System Requirements With Reacto And Vhdl, Frank C. Young

Theses and Dissertations

We develop a methodology for formalizing, verifying, and validating the requirements specification of real-time systems based on a graphical and formal hierarchical Finite State Machine (FSM) language Reacto. We define a means to quantify time and express real-time constraints in Reacto and a transformation from Reacto to the Very High Speed Integrated Circuit (VHSIC) hardware Description Language (VHDL). Reacto's high level abstractions, graphical nature, and theorem prover produce efficient, accurate, and easily understood specifications. We use VHDL's event driven simulation capability, concurrency, and temporal operators to thoroughly examine temporal dependencies between the state machine transitions, and to increase simulation power …

Creating And Manipulating Formalized Software Architectures To Support A Domain-Oriented Application Composition System, Cynthia G. Anderson

Theses and Dissertations

This research investigated technology which enables sophisticated users to specify, generate, and maintain application software in domain-oriented terms. To realize this new technology, a development environment, called Architect, was designed and implemented. Using canonical formal specifications of domain objects, Architect rapidly composes these specifications into a software application and executes a prototype of that application as a means to demonstrate its correctness before any programming language specific code is generated. Architect depends upon the existence of a formal object base (or domain model) which was investigated by another student in related research. The research described in this thesis relied on …

Automatic Surface Mount Solder Joints Inspection, Zhu Liu

Theses

This thesis reports the research results on automatic inspection of solder joints on printed circuit boards. The previous work on this subject has been advanced significantly in the following three aspects. With the support of AT&T Bell Lab, the most updated surface mount solder joints are inspected in this work instead of larger simulation solder joints or traditional through hole solder joints in the previous work. A small set of features is extracted for surface mount solder joints in both infrared and visual light inspection. A new image processing software named Khoros has been applied to improve the quality of …

An Application Of Neural Networks In Data Communication Real-Time Resource Reallocation, Qing Fan

Electrical & Computer Engineering Theses & Dissertations

This thesis presents an application of artificial neural networks in real-time resource reallocation, a methodology used in the implementation of an intelligent interface node in the Computer Integrated Manufacturing (CIM) environment. In particular, the problem is formulated using a Hopfield neural network model. The real-time reallocation problem is mapped into a two-dimensional matrix of neurons similar to Hopfield and Tank's approach to the traveling salesman problem (TSP) . An energy function is formulated in terms of the hard constraints and the solution cost. The interconnection weights and the input biases are determined by the energy function. It is shown through …

Implementation And Analysis Of Np-Complete Algorithms On A Distributed Memory Computer, Joel S. Garmon

Theses and Dissertations

The purpose of this research is to explore methods used to parallelize NP-complete problems and the degree of improvement that can be realized using different methods of load balancing. A serial and four parallel A* branch and bound algorithms were implemented and executed on an Intel iPSC/2 hypercube computer. One parallel algorithm used a global, or centralized, list to store unfinished work and the other three parallel algorithms used a distributed list to store unfinished work locally on each processor. the three distributed list algorithms are: without load balancing, with load balancing, and with load balancing and work distribution. The …

Boolean Reasoning And Informed Search In The Minimization Of Logic Circuits, James J. Kainec

Theses and Dissertations

The minimization of logic circuits has been an important area of research for more than a half century. The approaches taken in this field, however, have for the most part been ad hoc. Boolean techniques have been employed to manipulate formulas, but not to perform symbolic reasoning. Boolean equations are employed principally as icons; they are never solved. The first objective of this dissertation is to apply Boolean reasoning systematically and uniformly to the minimization problem. Boolean reasoning entails the reduction of systems of Boolean equations to a single equation; the single equation is an abstraction, independent of the form …

Developing Image Processing Tools In X Window System, Xin Zhang

Dissertations and Theses

The X Window System is an industry-standard software system which facilitates programmers to develop portable graphical user interfaces. This thesis describes an image processing tool developed under the X Window System. A multiwindow image display software with image editing and improvement functions is developed. The software has four modules: environment generation, image creation, image editing and image improvement.

The environment generation module creates working windows, scrollbars, dialogbox and pulldown menu buttons, and tracks mouse cursor positions. The working windows are three adjacent windows allowing display of three different images simultaneously. The dialogbox provides an interface between the user and the …

Ignoring Interprocessor Communication During Scheduling, Chintamani M. Patwardhan

Dissertations and Theses

The goal of parallel processing is to achieve high speed computing by partitioning a program into concurrent parts, assigning them in an efficient way to the available processors, scheduling the program and then executing the concurrent parts simultaneously. In the past researchers have combined the allocation of tasks in a program and scheduling of those tasks into one operation. We define scheduling as a process of efficiently assigning priorities to the already allocated tasks in a program. Assignment of priorities is important in cases when more than one task at a processor is ready for execution. Most heuristics for scheduling …