Computer Sciences Commons^™

A Pruning Procedure For Exact Graph Coloring, Thomas J. Sager, Shi-Jen Lin

Computer Science Technical Reports

The graph coloring problem can be stated: “Given an undirected graph, using a minimal number of colors, assign each vertex a color so that if two vertices are connected by an edge then they are not assigned the same color.” Graph coloring can be used to solve scheduling problems with constraints of the form: events e and e' can not be scheduled together. Graph coloring is an NP-Complete problem. Generally large problems are solved heuristically, although some of the better heuristic algorithms use an exact graph coloring algorithm to finish coloring a graph after first reducing it heuristically …

On The Worst Case Of Three Algorithms For Computing The Jacobi Symbol, Jeffrey Shallit

Computer Science Technical Reports

We study the worst-case behavior of three iterative algorithms- Eisenstein's algorithm, Lebesgue's algorithm, and the "ordinary" Jacobi symbol algorithm - for computing the Jacobi symbol. Each algorithm is similar in format to the Euclidean algorithm for computing gcd (u,v).

Asymptotically Fast Algorithms For Spherical And Related Transforms, James R. Driscoll, Dennis M. Healy

Computer Science Technical Reports

This paper considers the problem of computing the harmonic expansion of functions defined on the sphere. We begin by proving convolution theorems that relate the convolution of two functions on the sphere to a "multiplication" in the sprectral domain, as well as the multiplication of two functions on the sphere to a "convolution" in the spectral domain. These convolution theorems are then used to develop a sampling theorem on the sphere.

Symbolic Automation And Numerical Synthesis For Robot Kinematics, Jen Sriwattanathamma, Chung You Ho

Computer Science Technical Reports

This research analyzes three topics in robot arm kinematics. First, the direct kinematics which determines the Cartesian position and orientation of the end effector for the specified values of joint parameters is analyzed. Second, the differential motions concerning the differential relationships between the command variables in position and orientation of the end effector and the joint-controlled variables are studied. Finally, the inverse kinematics which determines the joint variables for a specified Cartesian position and orientation of the end effector is considered.

This dissertation presents a methodology for incorporating the artificial intelligence types of knowledge into automating solutions for the direct …

A Parallel Implementation Of Stickel's Ac Unification Algorithm In A Message-Passing Environment, David John Kleikamp, Ralph W. Wilkerson

Computer Science Technical Reports

Unification algorithms are an essential component of automated reasoning and term rewriting systems. Unification finds a set of substitutions or unifiers that, when applied to variables in two or more terms, make those terms identical or equivalent. Most systems use Robinson's unification algorithm or some variant of it. However, terms containing functions exhibiting properties such as associativity and commutativity may be made equivalent without appearing identical. Systems employing Robinson's unification algorithm must use some mechanism separate from the unification algorithm to reason with such functions. Often this is done by incorporating the properties into a rule base and generating equivalent …

A System For The Diagnosis Of Faults Using A First Principles Approach, Barbara A. Smith, Ralph W. Wilkerson

Computer Science Technical Reports

One of the primary areas of application of Artificial Intelligence is diagnosis. Diagnosis from first principles is a diagnostic technique which uses knowledge of the designed structure and function of a device to determine the possible causes of the malfunction.

This work builds on the foundation of a theory of diagnosis by implementing and extending the theory. A correction to the algorithm which defines the theory is presented. The theory is extended for multiple sets of observations of the system and measurement data.

A fundamental problem in diagnosis is selecting the measurement which will be of the most benefit in …

The Ipe-Pc Integrated Programming Environment, Nurcan Coskun, Thomas J. Sager

Computer Science Technical Reports

An Integrated Programming Environment, IPE-PC, that supports pseudo-code development has been designed and implemented. This environment is based on a Pascal-like language which is designed according to the requirements of a language-based environment. The nucleus of IPE-PC is a language-based editor which represents programs as graphs internally. The same representation is used in every mode of the environment (i.e., editing, compilation, execution, debugging and translation). The system provides facilities to take advantage of both top-down and bottom-up programming. Stepwise refinement has been supported by providing comment structures that can be transformed into procedures. Bottom-up programming is supported because it is …

Composite Graph Coloring Algorithms And Applications, Stephen Hong Seng Yek, Billy E. Gillett

Computer Science Technical Reports

A vertex-composite graph is a graph that can have unequal chromaticities on its vertices. Vertex-composite graph coloring or composite graph coloring involves coloring each vertex of a composite graph with consecutive colors according to the vertex's chromaticity with no two vertices adjacent to one another having the same color(s).

New heuristic algorithms including the use of the saturation degree method have been developed in this research. All eleven heuristic algorithms including Clementson and Elphick algorithms were then tested using random composite graphs with five different chromaticity distributions. The best algorithm which uses the least average colors from the experiment is …

Complete Sets Of Reductions Modulo A Class Of Equational Theories Which Generate Infinite Congruence Classes, Timothy B. Baird, Ralph W. Wilkerson

Computer Science Technical Reports

In this paper we present a generalization of the Knuth-Bendix procedure for generating a complete set of reductions modulo an equational theory. Previous such completion procedures have been restricted to equational theories which generate finite congruence classes. The distinguishing feature of this work is that we are able to generate complete sets of reductions for some equational theories which generate infinite congruence classes. In particular, we are able to handle the class of equational theories which contain the associative, commutative, and identity laws for one or more operators.

We first generalize the notion of rewriting modulo an equational theory to …

The Role Of Term Symmetry In E-Unification And E-Completion, Blayne E. Mayfield, Ralph W. Wilkerson

Computer Science Technical Reports

A major portion of the work and time involved in completing an incomplete set of reductions using an E-completion procedure such as the one described by Knuth and Bendix [070] or its extension to associative-commutative equational theories as described by Peterson and Stickel [PS81] is spent calculating critical pairs and subsequently testing them for coherence. A pruning technique which removes from consideration those critical pairs that represent redundant or superfluous information, either before, during, or after their calculation, can therefore make a marked difference in the run time and efficiency of an E-completion procedure to which it is applied.

The …

Computer Control Of A Pbx Washout Plant, Scott Cameron Sharp, Chung You Ho

Computer Science Technical Reports

A fully automated, computer controlled plant has been designed specifically for safe removal of plastic bonded explosives (PBX) from obsolete military munitions. This PBX washout plant consists of a two stage delivery system and robotically operated high pressure waterjet lance. The assigned task was to develop control packages for each component.

The first stage of the delivery system is a battery operated overhead trolley. Its control package consist of a dedicated computer, DC motor and custom positioning subprograms. The dedicated computer communicates through an infrared link to the operator's computer. This link was developed due to requirements of a hazardous …

Micro Database Management System Language, Karen Yingling Tam, George Winston Zobrist

Computer Science Technical Reports

There are two approaches to solve computational problems in a microcomputer environment:

1. Non-database approach: uses a high level programming language with non-database files as input and/or output files.
2. Database approach: uses the programming language embedded in the micro Data Base Management System(DBMS), with the database defined by the integrated database definition language as input and/or output files.

Adopting the appropriate approach in any single application may save cost and time. This paper compares the two different approaches while solving the same Control Section (CSECT) Interaction Hierarchy problem and suggests which to use when.

Deduction Of A Functional Dependency From A Set Of Functional Dependencies, James M. Richardson, Daniel C. St. Clair

Computer Science Technical Reports

This paper describes an algorithm called the Deduction Tracing Algorithm (DTA) which utilizes basic properties of functional dependencies from database systems and a modification of a tree search algorithm from artificial intelligence. The algorithm takes a set of functional dependencies, F, along with a specific functional dependency L → R as input and produces a list of functional dependencies from F that can be used to deduce L → R. The resulting algorithm is easily automated to provide relational database users with a tool for organizing their queries.

Intensity Blending Of Computer Image Generation-Based Displays, Elizabeth Scheppler Reidelberger, Daniel C. St. Clair

Computer Science Technical Reports

State-of-the-art combat simulators require a 360 degree field of view, allowing the pilot and radar intercept officer to have the same visibility in the simulator that they would experience in the aircraft. The sky/earth display must be computer - generated and displayed with a minimum of two channels to provide the most realistic display possible. The two channels of display come together in the dome, forming an equator, that must be as indiscernible to the aircrew as possible. To accomplish this, an algorithm has been developed for controlling the video output which makes the two separate channel displays appear as …

An Application Of A Fast Data Encryption Standard Implementation, Matt Bishop

Computer Science Technical Reports

The Data Encryption Standard is used as the basis for the UNIX password encryption scheme. Some of the security of that scheme depends on the speed of the implementation. This paper presents a mathematical formulation of a fast implementation of the DES in software, discusses how the mathematics can be translated into code, and then analyzes the UNIX password scheme to show how these results can be used to implement it. Experimental results are provided for several computers to show that the given method speeds up the computation of a password by roughly 20 times (depending on the specific computer).

Theft Of Information In The Take-Grant Protection Model, Matt Bishop

Computer Science Technical Reports

(Revised 5/90). Questions of information flow are in many ways more important than questions of access control, because the goal of many security policies is to thwart the unauthorized release of information, not merely the illicit obtaining of access rights to that information. The Take-Grant Protection Model is an excellent theoretical tool for examining such issues because conditions necessary and sufficienct for information to flow between tow objects, and for rights to object to be obtained or stolen, are known. In this paper we extend these results by examinig the question of information flow from an object the owner of …

The Sharing Of Rights And Information In A Capability-Based Protection System, Matt Bishop

Computer Science Technical Reports

The paper examines the question of sharing of rights and information in the Take-Grant Protection Model by concentrating on the similarities between the two; in order to do this, we state and prove new theorems for each that specifically show the similarities. The proof for one of the original theorems is also provided. These statements of necessary and sufficient conditions are contrasted to illustrate the proposition that transferring rights and transferring information are fundamentally the same, as one would expect in a capability-based system. We then discuss directions for future research in light of these results.

Multilist And Inverted File System Performance Measurements, Ashok Chandramouli, George Winston Zobrist

Computer Science Technical Reports

This study evaluates the multilist and inverted file systems. It describes the structure of the two file system and then proceeds to investigate the performance. The performance is based on quantitative estimates of space requirements for file system, time to retrieve records, time to insert a record, time to delete a record, time to update a record and time to exhaustively read and reorganize the file system. The study then investigates specific situations in which one file system seems to perform better than the other.

Performance Parameter Measurements Of Generic Files, Sankarraman Subramanian, George Winston Zobrist

Computer Science Technical Reports

This study discusses the performance parameter measurements of generic files, the pile file, the sequential file, the indexed-sequential file, the indexed file and the direct file. The file performance measurements are compiled in a software package. The study then describes the use of such software package as a simulation tool in a file design environment.

Heuristic Coloring Algorithm For The Composite Graph Coloring Problem, Johnnie C. Roberts, Billy E. Gillett

Computer Science Technical Reports

A composite graph is a finite undirected graph in which a positive integer known as a chromaticity is associated with each vertex of the graph. The composite graph coloring problem (CGCP) is the problem of finding the chromatic number of a composite graph, i.e., the minimum number of colors (positive integers) required to assign a sequence of consecutive colors to each vertex of the graph in a manner such that adjacent vertices are not assigned sequences with colors in common and the sequence assigned to a vertex has the number of colors indicated by the chromaticity of the vertex. The …

A Proposed C Language Binding For The Graphical Kernel System 3-D, M. G. Bolten, C. Y. Ho

Computer Science Technical Reports

This thesis introduces a proposed C language binding definition for the International standards Organization's draft international standard of the Graphical Kernel System-JD. This work augments the earlier C language binding of the two-dimensional version of the Graphical Kernel System commonly known as GKS. The proposed function interface will provide a basis for, if not a final, C language binding for the three-dimensional version of the Graphical Kernel System.

Medial Axis Transform Using Ridge Following, Richard Mark Volkmann, Daniel C. St. Clair

Computer Science Technical Reports

The intent of this investigation has been to find a robust algorithm for generation of the medial axis transform (MAT). The MAT is an invertible, object centered, shape representation defined as the collection of the centers of disks contained in the shape but not in any other such disk. Its uses include feature extraction, shape smoothing, and data compression. MAT generating algorithms include brushfire, Voronoi diagrams, and ridge following. An improved implementation of the ridge following algorithm is given. Orders of the MAT generating algorithms are compared. The effects of the number of edges in the polygonal approximation, shape area, …

Intensional Reasoning About Knowledge, Oliver B. Popov, Arlan R. Dekock

Computer Science Technical Reports

As demands and ambitions increase in Artificial Intelligence, the need for formal systems that facilitate a study and a simulation of a machine cognition has become an inevitability. This paper explores and developes the foundations of a formal system for propositional reasoning about knowledge. The semantics of every meaningful expression in the system is fully determined by its intension, the set of complexes in which the expression is confirmed. The knowledge system is based on three zeroth-order theories of epistemic reasoning for consciousness, knowledge and entailed knowledge. The results presented in the paper determine the soundness and the completeness of …

Matching Multiple Patterns From Right To Left, Samuel W. Bent, M A. Sridhar

Computer Science Technical Reports

We address the problem of matching multiple pattern strings against a text string. Just as the Aho-Corasick algorithm generalizes the Knuth-Morris-Pratt single-pattern algorithm to handle multiple patterns, we exhibit two generalizations of the Boyer-Moore algorithm to handle multiple patterns. In order to obtain worst-case time bounds better than quadratic, our algorithms remember some of the previous history of the matching.

Ethernet Performance: Design And Implementation Study, Michael M. Chaney, Tachen L. Lo, Daniel C. St. Clair

Computer Science Technical Reports

General concepts concerning local area network designs, functions and topologies will be presented. Ethernet as a multipoint bus topology local area network will be presented in detail. The Carrier Sense Multiple Access/Collision Detect (CSMA/CD) method of fairly regulating access to the shared network bus is studied. The Ethernet Network in relation to the Open Systems Interconnect (OSI) is reviewed, but only the layers pertaining to Ethernet are discussed throughout the majority of the paper. The specifications as described by Xerox, Digital and Intel are presented to help the designer understand the network's physical limitations. Analytical models are used to predict …

A Representation For Serial Robotic Tasks, Barry Ross Fox, Arlan R. Dekock

Computer Science Technical Reports

The representation for serial robotic tasks proposed in this thesis is a language of temporal constraints derived directly from a model of the space of serial plans. It was specifically designed to encompass problems that include disjunctive ordering constraints. This guarantees that the proposed language can completely and, to a certain extent, compactly represent all possible serial robotic tasks. The generality of this language carries a penalty. The proposed language of temporal constraints is NP-Complete. Specific methods have been demonstrated for normalizing constraints posed in this language in order to make subsequent sequencing and analysis more tractable. Using this language, …

A Dynamic Caching Algorithm Based On C. C. Chang's Ordered Minimal Perfect Hashing Scheme, Thomas J. Sager

Computer Science Technical Reports

No abstract provided.

Lily-A Generator For Compiler Frontends, Thomas J. Sager

Computer Science Technical Reports

In this paper, LILY, a generator for compiler frontends is described. LILY uses a generator of minimal perfect hash functions, MPHF , to create small fast compilers.

A Dynamic Caching Algorithm Based On C. C. Chang's Ordered Minimal Perfect Hashing Scheme, Thomas J. Sager

Computer Science Technical Reports

An algorithm for storage and retrieval in a small dynamic cache is presented. This algorithm is based on C.C. Chang’s ordered minimal perfect hashing scheme. Our algorithm has the property that it divides the set of objects that could occupy the cache into an arbitrary number of equivalence classes. The only restriction on which objects can occupy the cache are that no two objects in the same equivalence class can be in the cache at the same time. Retrieval from the cache is performed in constant time. Update of the cache is performed in logarithmic time.

Learning Object-Centered Representations, Peter Anthony Sandon

Computer Science Technical Reports

When we look at a familiar object from a novel viewpoint, we are usually able to recognize it. In this thesis, we address the problem of learning to recognize objects under transformations associated with viewpoint. Our vision model combines a hierarchical representation of shape features with an explicit representation of the transformation. Shape features are represented in a layered pyramid-shaped subnetwork, while the transformation is explicitly represented in an auxiliary subnetwork. The two connectionist networks are conjunctively combined to allow object- centered shape features to be computed in the upper layers of the network. A simulation of a 2-D translation …