Digital Commons Network^™

Network Key Management In A Large Distributed Environment, J. J. Stapleton, D. C. St. Clair

Computer Science Technical Reports

The technique of using encryption for protecting information in a network environment involves managing encryption keys within that same network. In large distributed networks the goal of achieving a secure environment requires a secure method of performing network key management. Network security, system security, and application security by means of data encryption rely on encryption keys remaining secret.

Both international and domestic standards organizations such as the International Organization for Standardization (ISO), the American National Standards Institute (ANSI), and the National Institute of Standards and Technology (NIST) address the issues of encryption through various standards. However, these standards discuss methods …

Multiprocessor File System Interfaces, David Kotz

Dartmouth Scholarship

MIMD multiprocessors are increasingly used for production super-computing. Supercomputer applications often have tremendous file I/O requirements. Although newer I/O sub-systems, which attach multiple disks to the multiprocessor, permit parallel file access, file system software often has insufficient support for parallel access to the parallel disks, which is necessary for scalable performance. Most existing multiprocessor file systems are based on the conventional file system interface (which has operations like open, close, read, write, and seek). Although this provides the familiar file abstraction, it is difficult to use for parallel access to a file. Scalable applications must cooperate to read or write …

Single Object Detection Using Multiple Sensors With Unknown Noise Distributions, Shaofen Chen

Computer Science Theses & Dissertations

We consider the design of an object classification system that identifies single objects using a system of sensors; each sensor outputs a random vector, according to an unknown (noise) probability distribution, in response to a sensed object. We consider a special class of systems, called the linearly separable systems, where the error-free sensor outputs corresponding to distinct objects can be mapped into disjoint intervals on real line. Given a set of sensor outputs corresponding to known objects, we show that a detection rule α_emp that approaches the correct rule with a high probability can be computed. We show …

Deterministic Approximations To Co-Production Problems With Service Constraints And Random Yields, Gabriel R. Bitran, Thin Yin Leong

Research Collection School Of Computing and Information Systems

Production planning problems where multiple item categories are produced simultaneously are examined. The items have random yields and are used to satisfy the demands of many products. These products have specification requirements that overlap. An item originally targeted to satisfy the demand of one product may be used to satisfy the demand of other products when it conforms to their specifications. Customers' demand must be satisfied from inventory. The problem is formulated with service constraints and a near-optimal solution is provided to the problem with a fixed planning horizon. Simple heuristics are proposed for the problem solved with a rolling …

An Enhanced Reconfigurable Embedding Scheme For Rings In Hypercubes, Junlin Liu, Bruce M. Mcmillin

Computer Science Technical Reports

In this paper we present an enhanced version of a reported reconfigurable embedding scheme (i.e., DC scheme) that based on the idea of divide and conquer to efficiently embed even length rings in hypercubes. It was shown that the system with the DC scheme is 3-step recoverable and needs an average of 1.3 steps to recover one single fault. Here, we show that the system with the enhanced embedding scheme will be 2-step recoverable when the dimensions of hypercubes are ~ 5, and the system is able to recover any single fault in an average of 1.1 steps.

Testing A Simple Polygon For Monotonicity Optimally In Parallel, Danny Z. Chen, Sumanta Guha

Department of Computer Science Technical Reports

No abstract provided.

The Development And Application Of Testing Techniques In An Object-Oriented Paradigm, Robert F. Kozal

Masters Theses

This thesis is the study of testing object-oriented programs. Aspects of object-oriented programs for which testing techniques are developed include classes, methods, inheritance, polymorphism, and encapsulation. The application of these techniques are illustrated, and a comparison between traditional testing techniques and object-oriented techniques is also drawn.

Modeling The Darpa Diesel Engine In Proengineer, Christoph M. Hoffmann

Department of Computer Science Technical Reports

No abstract provided.

A Vml Based Implementation Of A Neural Network Library On General Purpose Parallel Processors, H. Byun, S. K. Kortesis, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

Relaxing Synchronization In Distributed Simulated Annealing, Chul-Eui Hong, Bruce M. Mcmillin

Computer Science Technical Reports

Simulated annealing is an attractive, but expensive, heuristic for approximating the solution to combinatorial optimization problems. Attempts to parallelize simulated annealing, particularly on distributed memory multicomputers, are hampered by the algorithm's requirement of a globally consistent system state. In a multicomputer, maintaining the global state S Involves explicit message traffic and is a critical performance bottleneck. To mitigate this bottleneck, it becomes necessary to amortize the overhead of these state updates over as many parallel state changes as possible. By using this technique, errors in the actual cost C(S) of a particular state S will be introduced into the annealing …

The Architecture Of Pde Solving Systems, Elias N. Houstis, John R. Rice

Department of Computer Science Technical Reports

No abstract provided.

Integrating Distributed Data Sources Using Federated Objects, Henry R. Tirri, Jagannathan Srinivasan, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 8, Number 4, April 1992, 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.

Embedding Data Mappers With Distributed Memory Machine Compilers, Ravi Ponnusamy, Joel Saltz, Raja Das, Charles Koelbel, Alok Choudhary

Electrical Engineering and Computer Science - Technical Reports

In scalable multiprocessor systems, high performance demands that computational load be balanced evenly among processors and that interprocessor communication be limited as much as possible. Compilation techniques for achieving these goals have been explored extensively in recent years [3, 9, 11, 13, 17, 18]. This research has produced a variety of useful techniques, but most of it has assumed that the programmer specifies the distribution of large data structures among processor memories. A few projects have attempted to automatically derive data distributions for regular problems [12, 10, 8, 1]. In this paper, we study the more challenging problem of automatically …

A Probabilistic Analysis Of A Locality Maintaining Load Balancing Algorithm, Kishan Mehrotra, Sanjay Ranka, Jhy-Chun Wang

Electrical Engineering and Computer Science - Technical Reports

This paper presents a simple load balancing algorithm and its probabilistic analysis. Unlike most of the previous load balancing algorithms, this algorithm maintains locality. We show that the cost of this load balancing algorithm is small for practical situations and discuss some interesting applications for data remapping.

A Survey Of Computer Use In Occupational Therapy Fieldwork Sites, Martha E. Parks

Masters Theses

Eighty-three Western Michigan University occupational therapy fieldwork sites were surveyed to determine: (a) extent of computer use, (b) diagnostic categories with which computers are used, (c) extent of computer knowledge of registered occupational therapists (OTRs), and (d) adequacy of computer knowledge of fieldwork students. Forty-seven (56.6%) of the 83 surveys were returned. OTRs at 36 (76.6%) of the 47 sites currently use computers. Word processing is the most common way in which these OTRs use computers. The most common clinical use of computers is perceptual/motor assessment and treatment, while the most common research use of computers is for report writing. …

Algorithms For Incomplete Hypercubes, Venkata K. Prabhala

Masters Theses

Networked multiprocessing architectures for parallel com putation offer an alternative to high cost supercomputing. Recently hypercube has emerged as the most versatile architecture for parallel com putations. However, the number of nodes m in a hypercube is a power of 2, 2^d, where d is the dimension of the hypercube. In practice, it m ay not be possible to have a complete hypercube because the cost of upgradation is proportional to the num ber of nodes. Incomplete and Composite hypercubes help remove the exponential node(and hence cost) constraint.

In this thesis we establish the equality of m-node …

Feature Extraction And Classification Of Flir Imagery Using Relative Locations Of Non-Homogeneous Regions With Feedforward Neural Networks, Kevin L. Priddy

Theses and Dissertations

The classification of forward looking infrared (FLIR) imagery is explored using Gabor transform decomposition and relative locations of non- homogeneous regions combined with feedforward neural networks. A feature saliency metric is developed from a Bayesian sensitivity analysis of feedforward neural networks. This metric is then used to reduce the dimensionality of the feature vectors used to identify FLIR imagery without any degradation of classification accuracy. Several system architectures are developed using a roving window combined with a series of Gabor filters to produce feature vectors for presentation to a neural network classifier. One architecture uses the Gabor filter coefficients to …

On Planar Routing Of Multi-Terminal Nets In Vlsi Physical Design, Jahangir A. Hashmi

Masters Theses

In this thesis, we study two problems related to the physical design of VLSI circuits. One problem is related to the VLSI global routing and the other is related to the detailed routing in a bounded region.

We consider the routing of multiple multi-terminal nets on a single layer. We suggest a new approach for this problem. Our approach is based on simultaneously finding a forest of k non-intersecting spanning trees. We present an O(n^3) algorithm for finding two spanning trees corresponding to two nets on a single layer.

We also study the problem of finding a minimum Steiner tree …

Graph Theory Based Routing Algorithms, Bo Wu

Masters Theses

In this thesis, we study two VLSI layout problems.

We investigate the Minimum-Bend Single Row Routing Problem in which the objective function is to minimize the number of doglegs (or blends) per net. Our approach uses a graph theoretic representation in which an instance of the Single Row Routing Problem is represented by three graphs, an overlap graph, a containment graph and an interval graph. Using this graph representation, we develop three algorithms for minimum-bend single row routing problem.

We present a three-layer over-the-cell router (ICR-3) for the standard cell design style based on a new cell model which assumes …

Reasoning By Analogy In A Multi-Level System Architecture For The Design Of Mechanisms, Ghassan F. Issa

Computer Science Theses & Dissertations

Since the first attempts to integrate AI technology and engineering design nearly two decades ago, few expert systems have been shown to demonstrate sufficient reasoning capabilities to solve real-world design problems. The complex nature of design, the lack of understanding of the design process, and the limitations of current expert system technology have all been shown to have adverse effects on the maturity of this research area. Therefore, our direction in this research concentrates on understanding the design process, investigating a novel area of research focusing on creative design, and incorporating the results into a system model feasible for production …

Monitoring Computer Systems: An Intelligent Approach, Myron Zhihong Xu

Computer Science Theses & Dissertations

Monitoring modern computer systems is increasingly difficult due to their peculiar characteristics. To cope with this situation, the dissertation develops an approach to intelligent monitoring. The resulting model consists of three major designs: representing targets, controlling data collection, and autonomously refining monitoring performance. The model explores a more declarative object-oriented model by introducing virtual objects to dynamically compose abstract representations, while it treats conventional hard-wired hierarchies and predefined object classes as primitive structures. Taking the representational framework as a reasoning bed, the design for controlling mechanisms adopts default reasoning backed up with ordered constraints, so that the amount of data …

Formant Estimation From Dctc's Using A Feedforward Neural Network, Shubhangi U. Kelkar

Electrical & Computer Engineering Theses & Dissertations

Formants are the natural frequencies of the human vocal tract. Existing methods for estimating formants from speech signals are computationally complex and subject to errors for certain type of speech sounds. This thesis describes a method for estimating vowel formant frequencies from Discrete Cosine Transform Coefficients (DCTC's), a form of cepstral coefficients, using a feedforward neural network with back-propagation training. Experimental results are based on a large multispeaker data base. The results are obtained for both a linear transformation and a feedforward neural network with a nonlinear hidden layer. In general, the neural network transformation is superior to the linear …

A Visualization System For Correctness Proofs Of Graph Algorithms, Peter A. Gloor, Donald B. Johnson, Fillia Makedon, Panagiotis Metaxas

Computer Science Technical Reports

In this paper we describe a system for visualizing correctness proofs of graph algorithms. The system has been demonstrated for a greedy algorithm. Prim's algorithm for finding a minimum spanning tree of an undirected, weighted graph. We believe that our system is particularly appropriate for greedy algorithms, though much of what we discuss can guide visualization of proofs in other contexts. While an example is not a proof, our system provides concrete examples to illustrate the operation of the algorithm. These examples can be referred to by the user interactively and alternatively with the visualization of the proof where the …

An Algorithm For Generating Executable Assertions For Fault Tolerance, Martina Schollmeyer, Hanan Lutfiyya, Bruce M. Mcmillin

Computer Science Technical Reports

This paper presents an algorithm for deriving executable assertions that can be evaluated in a faulty distributed environment. A transformation from the global auxiliary variable approach into a new proof system based on the history of the auxiliary variables is introduced. This transformation, which matches the operational distributed environment more closely than the global auxiliary variable system, is then shown to retain the properties of this system such as noninterference, satisfaction, soundness, and completeness. An example is presented in which a model problem is transformed from one system into the other.

Macromolecular Electron Density Averaging On Distributed Memory Mimd Systems, Dan C. Marinescu, John R. Rice, Marius A. Cornea-Hasegan, Robert E. Lynch, Michael G. Rossmann

Department of Computer Science Technical Reports

No abstract provided.

A Pde Sparse Solver Benchmark For Massively Parallel Distributed Memory Multiprocessors, Mo Mu, John R. Rice

Department of Computer Science Technical Reports

No abstract provided.

Multiprocessor File System Interfaces, David Kotz

Computer Science Technical Reports

Increasingly, file systems for multiprocessors are designed with parallel access to multiple disks, to keep I/O from becoming a serious bottleneck for parallel applications. Although file system software can transparently provide high-performance access to parallel disks, a new file system interface is needed to facilitate parallel access to a file from a parallel application. We describe the difficulties faced when using the conventional (Unix-like) interface in parallel applications, and then outline ways to extend the conventional interface to provide convenient access to the file for parallel programs, while retaining the traditional interface for programs that have no need for explicitly …

Multiprocessor File System Interfaces, David Kotz

Dartmouth Scholarship

Increasingly, file systems for multiprocessors are designed with parallel access to multiple disks, to keep I/O from becoming a serious bottleneck for parallel applications. Although file system software can transparently provide high-performance access to parallel disks, a new file system interface is needed to facilitate parallel access to a file from a parallel application. We describe the difficulties faced when using the conventional (Unix-like) interface in parallel applications, and then outline ways to extend the conventional interface to provide convenient access to the file for parallel programs, while retaining the traditional interface for programs that have no need for explicitly …

The Interbase Parallel Language: Supporting The Flex Transaction Model And Beyond, Ahmed K. Elmagarmid, Jiansan Chen

Department of Computer Science Technical Reports

No abstract provided.