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1993

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Articles 211 - 240 of 428

Full-Text Articles in Computer Sciences

Implementing A Tool For Designing Portable Parallel Programs, Geetha Chitti May 1993

Implementing A Tool For Designing Portable Parallel Programs, Geetha Chitti

Theses

The Implementation aspects of a novel parallel programming model called Cluster-M is presented in this thesis. This model provides an environment for efficiently designing highly parallel portable software. The two main components of this model are Cluster-M Specifications and Cluster-M Representations. A Cluster-M Specification consists of a number of clustering levels emphasizing computation and communication requirements of a parallel solution to a given problem. A Cluster-M Representation on the other hand, represents a multi-layered partitioning of a system graph corresponding to the topology of the target architecture. A set of basic constructs essential for writing Cluster-M Specifications using PCN are …


Recursive Soft Morphological Filters, Padmaja Puttagunta May 1993

Recursive Soft Morphological Filters, Padmaja Puttagunta

Theses

Mathematical morphology which is based on set-theoretic concept, extracts object features by choosing a suitable structuring shape as a probe. Morphological filters are set operations that transform an image into a quantitative description of its geometrical structure: Appropriately used, they can eliminate noises or irrelevancies while preserv¬ing the details of the original image. The applications of morphological filters in image processing and analysis are numerous, which include shape recognition, industrial parts inspection, nonlinear filtering, and biomedical image processing.

Soft morphological filters are used for smoothing signals with the advantage of being less sensitive to additive noises and to small variations …


Graphical Deep Knowledge Representation In Vodak/Vml Object-Oriented Database, Jue Wang May 1993

Graphical Deep Knowledge Representation In Vodak/Vml Object-Oriented Database, Jue Wang

Theses

Applying Object-oriented concepts to the design of complex graphical interface has received great attention in the database and knowledge representation disciplines. Traditional CAD systems can not support efficient environments for design processes because they store information about all the objects for display purposes but do not store any knowledge for reasoning purposes. They are called "knowledge poor". "Graphical Deep Knowledge" in Artificial Intelligence has been proven successful to represent knowledge about objects for display purposes as well as reasoning purposes. We introduwd the theory of "Graphical Deep Knowledge" into the object-oriented database s stem VML to design a "Knowledge rich" …


Classification Of Patterns In Eeg Recordings : A Comparison Of Back-Propagation Networks Vs. Predictive Autoencoder Networks, Brian Armieri May 1993

Classification Of Patterns In Eeg Recordings : A Comparison Of Back-Propagation Networks Vs. Predictive Autoencoder Networks, Brian Armieri

Theses

Recent research exploring the use of neural networks for electro-encephalogram (EEG) pattern classification has found that a three-layer back-propagation network could be successfully trained to identify high voltage spike-and-wave spindle (HVS) patterns caused by epileptic seizures (Jando et. al., in press). However, there is no reason to predict that back-propagation is the best possible network architecture for EEG classification. A back-propagation neural network and a predictive autoencoder neural network were compared to determine which network was better at correct classifying both HVS and non-HVS patterns.

Both networks were able to classify 88%-89% of all patterns using a limited set of …


Throughput Of Existing Multiprocessor File Systems (An Informal Study), David Kotz May 1993

Throughput Of Existing Multiprocessor File Systems (An Informal Study), David Kotz

Computer Science Technical Reports

Fast file systems are critical for high-performance scientific computing, since many scientific applications have tremendous I/O requirements. Many parallel supercomputers have only recently obtained fully parallel I/O architectures and file systems, which are necessary for scalable I/O performance. Scalability aside, I show here that many systems lack sufficient absolute performance. I do this by surveying the performance reported in the literature, summarized in an informal table.


The State Of Computer Science Facilities Of Schools Across The United States That Are Comparable To Illinois Wesleyan University, Sarah A. Bartz '93 May 1993

The State Of Computer Science Facilities Of Schools Across The United States That Are Comparable To Illinois Wesleyan University, Sarah A. Bartz '93

Honors Projects

The purpose of this study is to compare Illinois Wesleyan's academic computer facilities with those at other comparable U.S. colleges and universities. This study also investigates factors affecting these facilities such as the methods other institutions use to deal with and plan for the constantly changing computer world. To obtain this information a survey was mailed to over 250 institutions across the U.S. that were considered comparable to IWU. These institutions include the Associated Colleges of the Midwest, the Oberlin Group, and some of the top colleges and universities in the U.S. as ranked in U.S. News and World Report's …


Diagnosis Of Malignant Melanoma Using A Neural Network, Anurag Chawla, Fikret ErçAl May 1993

Diagnosis Of Malignant Melanoma Using A Neural Network, Anurag Chawla, Fikret ErçAl

Computer Science Technical Reports

Malignant melanoma is the deadliest form of all skin cancers. Approximately 32,000 new cases of malignant melanoma were diagnosed in 1991, with approximately 80 percent of patients expected to survive five years [1], Fortunately, if detected early, even malignant melanoma may be treated successfully. Thus, in recent years, there has been a rising interest in the automated detection and diagnosis of skin cancer, particularly malignant melanoma [2]. In this thesis, a novel neural network approach for the automated distinction of melanoma from three benign categories of tumors which exhibit melanoma-like characteristics is presented. The approach is based on devising new …


An Analysis Of Modern Cryptosystems, Thomas Gerald Sauder, Chung You Ho May 1993

An Analysis Of Modern Cryptosystems, Thomas Gerald Sauder, Chung You Ho

Computer Science Technical Reports

Since the ancient Egyptian empire, man has searched for ways to protect information from getting into the wrong hands. Julius Caesar used a simple substitution cipher to protect secrets. During World War II, the Allies and the Axis had codes that they used to protect information. Now that we have computers at our disposal, the methods used to protect data in the past are ineffective. More recently, computer scientists and mathematicians have been working diligently to develop cryptosystems which will provide absolute security in a computing environment.

The three major cryptosystems in use today are DES, RSA, and the Knapsack …


Parallel Genetic Algorithms For The Dag Vertex Splitting Problem, Matthias Mayer, Fikret ErçAl May 1993

Parallel Genetic Algorithms For The Dag Vertex Splitting Problem, Matthias Mayer, Fikret ErçAl

Computer Science Technical Reports

Directed Acyclic Graphs are often used to model circuits and networks. The path length in such Directed Acyclic Graphs represents circuit or network delays. In the vertex splitting problem, the objective is to determine a minimum number of vertices from the graph to split such that the resulting graph has no path of length greater than a given δ. The problem has been proven to be NP-hard.

A Sequential Genetic Algorithm has been developed to solve the DAG Vertex Splitting Problem. Unlike a standard Genetic Algorithm, this approach uses a variable chromosome length to represent the vertices that split the …


The Interpolating Random Spline Cryptosystem And The Chaotic-Map Public-Key Cryptosystem, Fengi Hwu, Chung You Ho May 1993

The Interpolating Random Spline Cryptosystem And The Chaotic-Map Public-Key Cryptosystem, Fengi Hwu, Chung You Ho

Computer Science Technical Reports

The feasibility of implementing the interpolating cubic spline function as encryption and decryption transformations is presented. The encryption method can be viewed as computing a transposed polynomial. The main characteristic of the spline cryptosystem is that the domain and range of encryption are defined over real numbers, instead of the traditional integer numbers. Moreover, the spline cryptosystem can be implemented in terms of inexpensive multiplications and additions.

Using spline functions, a series of discontiguous spline segments can execute the modular arithmetic of the RSA system. The similarity of the RSA and spline functions within the integer domain is demonstrated. Furthermore, …


The Design, Analysis, And Implementation Of Parallel Simulated Annealing And Parallel Genetic Algorithms For The Composite Graph Coloring Problem, Brent S. Elmer, Billy E. Gillett May 1993

The Design, Analysis, And Implementation Of Parallel Simulated Annealing And Parallel Genetic Algorithms For The Composite Graph Coloring Problem, Brent S. Elmer, Billy E. Gillett

Computer Science Technical Reports

The composite graph coloring problem (CGCP) is similar to the standard graph coloring problem (SGCP). Associated with each vertex of a composite graph is a positive integer which represents the chromaticity of that vertex. This number is the number of consecutive integers (colors) which must be assigned to the vertex. The goal of the CGCP is to color the graph with as few colors as possible. The largest integer used in the coloring is called the chromatic number of the graph. The CGCP is proven to be NP-complete.

Exact, heuristic, and stochastic methods are analyzed and compared. Exact methods are …


Considerations For Rapidly Converging Genetic Algorithms Designed For Application To Problems With Expensive Evaluation Functions, Richard Patrick Rankin, Ralph W. Wilkerson May 1993

Considerations For Rapidly Converging Genetic Algorithms Designed For Application To Problems With Expensive Evaluation Functions, Richard Patrick Rankin, Ralph W. Wilkerson

Computer Science Technical Reports

A genetic algorithm is a technique designed to search large problem spaces using the Darwinian concepts of evolution. Solution representations are treated as living organisms. The procedure attempts to evolve increasingly superior solutions. As in natural genetics, however, there is no guarantee that the optimum organism will be produced.

One of the problems in producing optimal organisms in a genetic algorithm is the difficulty of premature convergence. Premature convergence occurs when the organisms converge in similarity to a pattern which is sub-optimal, but insufficient genetic material is present to continue the search beyond this sub-optimal level, called a local maximum. …


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 5, May 1993, College Of Engineering And Computer Science, Wright State University May 1993

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 5, May 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Cartographic Pattern Recognition Using Template Matching, Angela G. Lammers, Ralph W. Wilkerson, Fikret ErçAl May 1993

Cartographic Pattern Recognition Using Template Matching, Angela G. Lammers, Ralph W. Wilkerson, Fikret ErçAl

Computer Science Technical Reports

In creating digital maps from paper maps, the paper map must first be scanned to produce a raster image, and then converted into vector format. Vector format allows non-graphical cartographic information to be stored along with the graphical objects. At the United States Geological Survey, the conversion from raster to vector format is performed by a commercial software package. The package also attempts to classify the graphical objects based on shape, line patterns, and other information gained from the raster file. Since the package frequently fails to classify a significant percentage of the elements in the map, manual map analysis …


The Third International Conference On Expert Systems For Numerical Computing, Elias N. Houstis, John R. Rice, Robert Vichnevetsky May 1993

The Third International Conference On Expert Systems For Numerical Computing, Elias N. Houstis, John R. Rice, Robert Vichnevetsky

Department of Computer Science Technical Reports

No abstract provided.


Broadcast Methods In The Multiswitch Point-To-Point Network, Douglas E. Comer, Victor Norman May 1993

Broadcast Methods In The Multiswitch Point-To-Point Network, Douglas E. Comer, Victor Norman

Department of Computer Science Technical Reports

No abstract provided.


On The Multisearching Problem For Hypercubes, Mikhail J. Atallah, Andreas Fabri May 1993

On The Multisearching Problem For Hypercubes, Mikhail J. Atallah, Andreas Fabri

Department of Computer Science Technical Reports

No abstract provided.


Some Experiments With A Basic Linear Algebra Routine On Distributed Memory Parallel Systems, H. Byun, Elias N. Houstis, E. A. Vavalis May 1993

Some Experiments With A Basic Linear Algebra Routine On Distributed Memory Parallel Systems, H. Byun, Elias N. Houstis, E. A. Vavalis

Department of Computer Science Technical Reports

No abstract provided.


Accurate Verification Of Five-Axis Numerically Controlled Machining, Jerome L. Quinn May 1993

Accurate Verification Of Five-Axis Numerically Controlled Machining, Jerome L. Quinn

Dartmouth College Ph.D Dissertations

Current automated machining systems are composed of a number of components to aid in bringing a surface from design to physical completion. Numerically controlled (NC) milling machines are used to cut parts out of stock. Programming these machines to cut a desired surface is still largely a matter of experienced human participation. Therefore, the need exists to verify that tool programs produce the desired part.

We present recent developments in the verification of NC tool programs. Many of these methods rely on approximating the stock material as vectors whose lengths reflect the amount of uncut material at any point. This …


Disk Subsystem Performance And Reliability Enhancements Through The Use Of Carnival Mirrors, Darrell G. Suggs May 1993

Disk Subsystem Performance And Reliability Enhancements Through The Use Of Carnival Mirrors, Darrell G. Suggs

All Dissertations

Performance and reliability modeling of computer systems continues to be an area of active research. Analytic and simulation modeling of computer systems and subsystems provides a cost effective means of system design, system expansion, and system tuning. Recent breakthroughs in computational power, coupled with the continuing development of the performance and reliability modeling field, now provide us with an opportunity to begin to answer design questions previously considered far out of reach.

Traditional computer systems contained only single-unit disk subsystems. Many current computer systems have multiple-unit disks that are treated as a single logical unit. These multiple disk systems provide …


Partially Preemptible Hash Joins, Hwee Hwa Pang, Michael J. Carey, Miron Livny May 1993

Partially Preemptible Hash Joins, Hwee Hwa Pang, Michael J. Carey, Miron Livny

Research Collection School Of Computing and Information Systems

With the advent of real-time and goal-oriented database systems, priority scheduling is likely to be an important feature in future database management systems. A consequence of priority scheduling is that a transaction may lose its buffers to higher-priority transactions, and may be given additional memory when transactions leave the system. Due to their heavy reliance on main memory, hash joins are especially vulnerable to fluctuations in memory availability. Previous studies have proposed modifications to the hash join algorithm to cope with these fluctuations, but the proposed algorithms have not been extensively evaluated or compared with each other. This paper contains …


The Investigation Of Object-Oriented Methodology As An Enabling Technique For End-User Application Development, Eng Chong Lim Apr 1993

The Investigation Of Object-Oriented Methodology As An Enabling Technique For End-User Application Development, Eng Chong Lim

Honors Theses

This research studies the value of object-oriented methods to design information systems that can then be developed and implemented by end-users.


Resource Utilization Model For The Algorithm To Architecture Mapping Model, Rakesh R. Patel Apr 1993

Resource Utilization Model For The Algorithm To Architecture Mapping Model, Rakesh R. Patel

Electrical & Computer Engineering Theses & Dissertations

The analytical model for resource utilization, and the variable node time and conditional node model for the enhanced ATAMM model for a real-time data flow architecture, is presented in this research. The Algorithm To Architecture Mapping Model, ATAMM, is a Petri net based graph theoretic model developed at Old Dominion University, and is capable of modeling the execution of large-grained algorithms on a real-time data flow architecture. Using the resource utilization model, the resource envelope may be obtained directly from a given graph and, consequently, the maximum number of required resources may be evaluated. The node timing diagram for one …


A Performance Prediction Model For A Fault-Tolerant Computer During Recovery And Restoration, Rodrigo A. Obando Apr 1993

A Performance Prediction Model For A Fault-Tolerant Computer During Recovery And Restoration, Rodrigo A. Obando

Electrical & Computer Engineering Theses & Dissertations

The modeling and design of a fault-tolerant multiprocessor system is addressed in this dissertation. In particular, the behavior of the system during recovery and restoration after a fault has occurred is investigated. Given that a multicomputer system is designed using the Algorithm to Architecture To Mapping Model (ATAMM) model, and that a fault (death of a computing resource) occurs during its normal steady-state operation, a model is presented as a viable research tool for predicting the performance bounds of the system during its recovery and restoration phases. Furthermore, the bounds of the performance behavior of the system during this transient …


Fast Fourier Transforms On Distributed Memory Parallel Machines, Anshu Dubey Apr 1993

Fast Fourier Transforms On Distributed Memory Parallel Machines, Anshu Dubey

Computer Science Theses & Dissertations

One issue which is central in developing a general purpose subroutine on a distributed memory parallel machine is the data distribution. It is possible that users would like to use the subroutine with different data distributions. Thus there is a need to design algorithms on distributed memory parallel machines which can support a variety of data distributions. In this dissertation we have addressed the problem of developing such algorithms to compute the Discrete Fourier Transform (DFT) of real and complex data. The implementations given in this dissertation work for a class of data distributions commonly encountered in scientific applications, known …


Time-Optimal Algorithms On Meshes With Multiple Broadcasting, Dharmavani Bhagavathi Apr 1993

Time-Optimal Algorithms On Meshes With Multiple Broadcasting, Dharmavani Bhagavathi

Computer Science Theses & Dissertations

The mesh-connected computer architecture has emerged as a natural choice for solving a large number of computational tasks in image processing, computational geometry, and computer vision. However, due to its large communication diameter, the mesh tends to be slow when it comes to handling data transfer operations over long distances. In an attempt to overcome this problem, mesh-connected computers have recently been augmented by the addition of various types of bus systems. One such system known as the mesh with multiple broadcasting involves enhancing the mesh architecture by the addition of row and column buses. The mesh with multiple broadcasting …


Recognition Of Quadric Surfaces From Range Data: An Analytical Approach, Ivan X. D. D'Cunha Apr 1993

Recognition Of Quadric Surfaces From Range Data: An Analytical Approach, Ivan X. D. D'Cunha

Electrical & Computer Engineering Theses & Dissertations

In this dissertation, a new technique based on analytic geometry for the recognition and description of three-dimensional quadric surfaces from range images is presented. Beginning with the explicit representation of quadrics, a set of ten coefficients are determined for various three-dimensional surfaces. For each quadric surface, a unique set of two-dimensional curves which serve as a feature set is obtained from the various angles at which the object is intersected with a plane. Based on a discriminant method, each of the curves is classified as a parabola, circle, ellipse, hyperbola, or a line. Each quadric surface is shown to be …


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 4, April 1993, College Of Engineering And Computer Science, Wright State University Apr 1993

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 4, April 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Efficient Parallel Algorithms For Some Tree Layout Problems, J Diaz, A Gibbons, Grammati E. Pantziou, M Serna, Paul G. Spirakis, J Toran Apr 1993

Efficient Parallel Algorithms For Some Tree Layout Problems, J Diaz, A Gibbons, Grammati E. Pantziou, M Serna, Paul G. Spirakis, J Toran

Computer Science Technical Reports

The minimum cut and minimum length linear arrangement problems usually occur in solving wiring problems and have a lot in common with job sequencing questions. Both problems are NP-complete for general graphs and in P for trees. We present here two algorithms in NC. The first solves the minimum length linear arrangement problem for unrooted trees in $O(\log^2 n)$ time and $O(n^2 3^{\log n})$ CREW PRAM processors. The second algorithm solves the minimum cut arrangement for unrooted trees of maximum degree $d$ in $O(d \log^2 n)$ time and $O(n^2 /\log n)$ CREW PRAM processors.


Topology Based Routing Algorithms For Multilayer Ic Layout Design, Moazzem Hossain Apr 1993

Topology Based Routing Algorithms For Multilayer Ic Layout Design, Moazzem Hossain

Masters Theses

In this thesis, we consider the multilayer topological routing problem and also the geometric routing problem based on topological routing solution. We show that the problem of multilayer topological planar routing for any arbitrary routing region can be modeled as a problem in a simple closed routing region. We also show that the solution to the multilayer planar routing leads to a better result of the topological via minimization problem. We present a provably-good approximation algorithm for the multilayer topological planar routing problem for different routing regions.

We also propose a graph theoretic algorithm to find 2-layer topological solutions that …