Computer Sciences Commons^™

Modeling Of Supersonic Combustor Flows Using Parallel Computing, Bruce M. Mcmillin, Eric Jui-Lin Lu, Larry Reeves

Computer Science Technical Reports

Computational Fluid Dynamics (CFD) has matured rapidly in the past 20 years and is now an important tool for analyzing and understanding complex fluid flows. Since 1985, CFD has played a vital role in the study of hypersonic flight. It has provided the capability for scientists and engineers to model both internal and external hypersonic flow-fields. Such flows are often impractical or impossible to analyze in laboratory conditions. In particular, the recent application of CFD to the modeling of internal reacting supersonic combustor flows has significantly advanced the understanding of such flows and has increased confidence in the predictive ability …

The Computation Of Supersonic Combustor Flows Using Multi-Computers, Bruce M. Mcmillin, Eric Jui-Lin Lu, Larry Reeves

Computer Science Technical Reports

An explicit computational fluid dynamics (CFD) computer code with parallel processing capability has been developed for the purpose of simulating internal high-speed reacting flows. The code solves the three-dimensional Navier-Stokes equations for compressible flows. The CFD code can be executed on either sequential (single processor) computers or multi-computers (multiple processor machines with distributed memory and message passing between processors). The parallel implementation involves homogeneous domain decomposition between processors with message passing needed only between neighbor processors. The code is validated for a compression ramp, an expansion ramp, a viscous flat plate, and a viscous flat plate with wall injection. These …

How To Program In Ccsp, Elizabeth Arrowsmith, Bruce M. Mcmillin

Computer Science Technical Reports

No abstract provided.

Formal Method For Scheduling, Routing And Communication Protocol, Lenore Mullin, S. A. Thibault, D. R. Dooling, E. A. Sandberg

Computer Science Faculty Research & Creative Works

The PRAM model has been shown to be an optimal design for emulating both loose and tightly coupled multiprocessors for unit time operations. When virtual processors are required, multiplexing work to available processors is employed. This introduces a form of latency incurred by operating system overhead. Further complications arise when bandwidth creates bottlenecking of work units. G.E. Blelloch (1989) showed how to add parallel prefix operations (scans) to an extended PRAM model which uses unit step, not time operations. This paper shows how the psi) calculus can be used to group work units, i.e., pipelining the work units, so that …

Functional Representation And Reasoning About The F/A-18 Aircraft Fuel System, M. Pegah, J. Sticklen, William E. Bond

Computer Science Faculty Research & Creative Works

Functional reasoning, a subfield of model-based reasoning, is discussed. This approach uses abstractions of a device's purpose to index behaviors that achieve that purpose. Functional modeling, a variation on this method, also uses simulation as a core reasoning strategy. The complex causal knowledge of a device along functional lines is decomposed, then a causal story of how the device will operate in a particular situation given stated boundary conditions is composed. The application of the functional approach to modeling the fuel system of a F/A-18 aircraft is described. The representation of the F/A-18 fuel system includes 89 component devices, 92 …

Genetic Algorithms With 3-Parent Crossover, L. Vincent Edmondson

Doctoral Dissertations

"A new genetic algorithm which uses a 3-parent uniform crossover operator is developed and analyzed. Uniform crossover operators are shown to be based on the premise that all bit-level genetic information should be passed from parents to children. The 3-parent uniform crossover operator is shown to adhere to this premise. The 3-parent uniform crossover operator is shown to be better than the 2-parent uniform crossover operator on the De Jong test functions.

Two new genetic algorithms which use 3-parent traditional crossover operators are developed and analyzed. The first uses a strategy of randomly selecting 3 of the 6 children resulting …

Detection Of Skin Tumor Boundaries In Color Images, Fikret Erçal, M. Moganti, William V. Stoecker, Randy Hays Moss

Computer Science Faculty Research & Creative Works

A simple and yet effective method for finding the borders of tumors is presented as an initial step towards the diagnosis of skin tumors from their color images. The method makes use of an adaptive color metric from the red, green, and blue planes that contains information for discriminating the tumor from the background. Using this suitable coordinate transformation, the image is segmented. The tumor portion is then extracted from the segmented image and borders are drawn. Experimental results that verify the effectiveness of this approach are given

Ensuring The Satisfaction Of A Temporal Specification At Run-Time, Grace Tsai, Matt Insall, Bruce M. Mcmillin

Computer Science Technical Reports

This paper presents an approach to operationally evaluate a temporal specification in a distributed computing environment. First, an algorithm Compute History is proposed to allow every distributed processor to collect events executed by itself and by other processors, and to order the collected events by causality. This algorithm employs neither monitors nor a global clock to order collected events of a processor. These collected events of a processor form an execution history of a distributed computation, and they represent behaviors of all the processors during execution. Next, the semantics of operational evaluation of a temporal assertion is presented. The evaluation …

An Object Oriented Preemptive Multitasking Kernel, Lee Gene Shipman

Masters Theses

“This paper describes a preemptive multitasking kernel designed and coded using C++ using an object oriented paradigm. The kernel design, while implemented on an Intel 80386 based IBM PC running MS-DOS 4.01, can be ported to any platform, rewriting only the low level, hardware specific code.

The kernel, in application framework form, enables the applications developer to create real-time multitasking applications. This can be done in a systematic way by capitalizing on the power of object oriented program development.

A simulation was created to verify the correctness of the kernel against a traditional non-multitasking approach. This simulation provides the proof …

X.500 Directory Service Support For Electronic Mail, Mihai G. Sirbu

Masters Theses

"One of the difficult problems on the Internet is finding the electronic mail addresses of users. In practice, there are some indirect ways of finding these addresses such as the finger program in UNIX, but almost all of these methods require the user to know the exact host name of the destination. What is most desirable is an automated mechanism which provides the e-mail addresses of users if some minimal information about the destination site is known.

This thesis describes the design of such a directory service support system, based on the X.500 Series of CCITT Recommendation, for the elm …

Neural Network Diagnosis Of Malignant Melanoma From Color Images, Fikret ErçAl, C. Chawla, William V. Stoecker, Randy Hays Moss

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 paper, we present a novel neural network approach for the automated separation of melanoma from three other benign categories of tumors which exhibit melanoma-like characteristics. Our approach is based on devising …

Visual Inspection Algorithms For Printed Circuit Board Patterns A Survey, Madhav Moganti, Fikret ErçAl, Cihan H. Dagli

Computer Science Technical Reports

The importance of the inspection process has been magnified by the requirements of the modern manufacturing environment. In electronics mass-production manufacturing facilities, an attempt is often made to achieve 100 % quality assurance of all parts, subassemblies, and finished goods. A variety of approaches for automated visual inspection of printed circuits have been reported over the last two decades. In this survey, algorithms and techniques for the automated inspection of printed circuit boards are examined. A classification tree for these algorithms is presented and the algorithms are grouped according to this classification. This survey concentrates mainly on image analysis and …

An Application-Oriented Approach To Distributed Error-Detecting Branch & Bound, Aggie Y. Sun, Hanan Lutfiyya, Bruce Mcmillin

Computer Science Technical Reports

An important aspect which is often overlooked in software _design of distributed environments is that of fault tolerance. Many methodologies in the past have attempted to provide fault tolerance efficiently, but have never been successful at eliminating explicit time and space redundancy. One approach is the Application-Oriented Fault Tolerance Paradigm, which provides fault tolerance by examining the behavior and properties of the application and deriving executable assertions for the detection of faults. Previous work has demonstrated the feasibility of the application-oriented fault tolerance paradigm for various applications. However, the executable assertions were guided by the natural constraints of the problem. …

An Improved Characterization Of 1-Step Recoverable Embeddings: Rings In Hypercubes, Junlin Liu, Thomas J. Sager, Bruce M. Mcmillin

Computer Science Technical Reports

An embedding is said to be 1-step recoverable if any single fault in the embedding can be recovered in one reconfiguration step. In this paper we present a heuristic approach to construct such 1-step recoverable embeddings. We show that to embed a k (even) length ring in ad-cube, where 6 < = k < = 3/4 2d and d < = 3, our scheme will guarantee finding a 1-step recoverable embedding, provided such an embedding exists. Compared to other previously proposed schemes, our scheme achieves much better results. A sufficient condition for the non-existence of 1-step recoverable embeddings for embedding rings of length > 3/4 2d in d-cubes is also given.

Using Minimal And Maximal Fault Tolerance For The Assessment Of Fault-Tolerant Algorithms, Martina Schollmeyer, Bruce M. Mcmillin

Computer Science Technical Reports

No abstract provided.

Fault-Tolerant Distributed Deadlock Detection / Resolution, Pei-Yu Liu, Bruce M. Mcmillin

Computer Science Technical Reports

The problem of deadlock detection in a distributed system has been extensively studied in the past few years. Many algorithms on distributed deadlock detection have been proposed under the assumption that the processors and communication in the system are fault-free. However, in an unreliable distributed system, faulty processors may prevent a deadlock detection algorithm from properly detecting deadlocks. Few of the algorithms proposed in the literature address the issue of handling process failures in a distributed system. This paper proposes a fault-tolerant distributed deadlock detection algorithm which integrates a priority-based probe algorithm with a PMC-based diagnosis model. This algorithm detects …

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. Since simulated annealing is a general purpose method, it can be applied to the broad range of NP-complete problems such as the traveling salesman problem, graph theory, and cell placement with a careful control of the cooling schedule.

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. One way to mitigate this bottleneck …

A Process-Learning Pid Controller Algorithm Utilizing An On-Line Iterative Improvement Technique, Ryan Rosandich, Ralph W. Wilkerson

Computer Science Technical Reports

Three iterative improvement algorithms are presented for the determination of process controller gains. An offline algorithm is developed and tested as a basis for comparison, and a simple on-line algorithm is developed as an incremental step toward the final algorithm, proportional on-line iterative improvement. The algorithms are based on an Artificial Neural Network learning method, and this method is compared with other control optimization techniques. The performance of each of the algorithms was experimentally evaluated in numerous realistically simulated process control situations consisting of flow, level, and temperature control loops with various values of dead-time and process noise. The experimental …

The Management Of Replicated Data, Hsueh-Chi Shih, C. Y. Ho, S. Alptekin

Computer Science Technical Reports

Data replication, which has the benefits of improving system availability and read performance, proved to be indispensable to many database applications. In a replicated database, the one-copy serializability of transaction executions can be ensured by employing a replica control mechanism on top of the traditional concurrency control mechanism. This work contains two replica control algorithms and a read-only transaction processing algorithm. Both replica control algorithms handle multiple site, communication and partitioning failures. The replica control algorithms achieve read operation efficiency by always translating a logical read operation into one local physical read operation and by taking advantage of the locality …

Formal Derivation Of An Error-Detecting Distributed Data Scheduler Using Changeling, Hanan Lutffiya, Bruce M. Mcmillin, Alan Su

Computer Science Technical Reports

Distributed database applications are a wide use of distributed systems. One of the major advantages of distributed database systems is the potential for achieving high availability in the presence of faults. Faults must be handled so that the system still operates or operates in a degraded mode. This paper focuses on being able to detect component errors which can lead to system failures in the scheduling part of the lock manager portion of the distributed database system by using embedded executable assertions. Changeling provides a systematic approach, based on the mathematical model of program verification, to deriving executable assertions that …

An Analysis Of Product Metrics In Terms Of Qualitative And Formal Metric Properties, Tuliz Dengi, George Zobrist

Computer Science Technical Reports

In recent years, the increased concern for developing reliable, cost-efficient software systems has been accompanied by a higher need to analyze and measure software complexity. Numerous metrics have been proposed to measure software complexity and functionality. Yet, testing the validity of these metrics has been a difficult and long process. As an initial test of metric validity, some researchers have suggested the use of formal metric properties so that metrics without a sound theoretical base are rejected right away. This approach has the additional advantage of allowing a reasonable and fair comparison of software metrics.

In this study, a discussion …

An Object-Oriented Approach To Data Exchange Applications: Development Of A Class Library For The Spatial Data Transfer Standard, Phyllis Altheida, John Prater

Computer Science Technical Reports

The object-orienced paradigm embodies a set of concepts that differentiates it from process-oriented and data-oriented methods. Among che commonly included principles are object, class, encapsulation, inheritance and polymorphism. The synergism of the concepts creates a powerful and new perspective that can be applied to all phases of systems development. Application developers need to try out the object-oriented languages, methodologies and development tools to help define its niche. The problem domain of data transfer standards is used to test the applicability of object-oriented techniques. Data transfer standards have three levels of abstraction: conceptual, logical, and format. The Spatial Data Transfer Standard …

An Animation System For Shift Reduce Parsers, M. S. Mandl, T. J. Sager, D. C. St. Clair

Computer Science Technical Reports

This paper presents the design and implementation of the Parse Display Utility (POU) system. This system introduces a mechanism to augment traditional methods of exploring parsing theory by providing a PRESENTATION scheme which allows a user to view the operation of a shift-reduce parser.

The overall operation of the tool revolves around an LALR (LookAhead LR) parser/parser generator and is managed by a Graphical User-Interface (GUI) developed using Borland's Turbo Vision product. The GUI allows access to a facility which draws derivation trees in Turbo Pascal graphics. This parse tree facility utilizes an algorithm which can easily be ported to …

Effect Of The X² Test On Construction Of Id3 Decision Trees, Mayank Thakore, Daniel C. St. Clair

Computer Science Technical Reports

Inductive machine learning algorithms are knowledge-based learning algorithms which take training instances as input and produce knowledge as output. One popular induction algorithm is Quinlan's ID3 [1986]. This algorithm produces knowledge in the form of a decision tree. Each path in the tree can be interpreted as a rule with the leaves representing rule conclusions. Selected attributes which describe the training instances form the interior nodes of the tree.

The ID3 algorithm is extremely sensitive to noisy training data. In an effort to reduce the effects of noise on tree construction, Quinlan used the X² test to identify noisy …

Formal Generation Of Executable Assertions For Application-Oriented Fault Tolerance, Hanan Lutfiyya, Martina Schollmeyer, Bruce M. Mcmillin

Computer Science Technical Reports

Executable assertions embedded into a distributed computing system can provide run-time assurance by ensuring that the program state, in the actual run-time environment, is consistent with the logical stage specified in the assertions; if not, then an error has occurred and a reliable communication of this diagnostic information is provided to the system such that reconfiguration and recovery can take place. Application- oriented fault tolerance is a method that provides fault detection using executable assertions based on the natural constraints of the application.

This paper focuses on giving application-oriented fault tolerance a theoretical foundation by providing a mathematical model for …

Neural Modeling And Control Of A Distillation Column, James Edward Steck, K. Krishnamurthy, Bruce M. Mcmillin, Gary G. Leininger

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Control of a nine-stage three-component distillation column is considered. The control objective is achieved using a neural estimator and a neural controller. The neural estimator is trained to represent the chemical process accurately, and the neural controller is trained to give an input to the chemical process which will yield the desired output. Training of both the neural networks is accomplished using a recursive least squares training algorithm implemented on an Intel iPSC/2 multicomputer (hypercube). Simulated results are presented for a numerical example.

Fault Tolerance In Concurrent Systems Through Formal Methods, H. Lutfiyya, B. M. Mcmillin

Computer Science Technical Reports

An important aspect which is often overlooked in the software design cycle is the question of assurance. Many methodologies in the past have attempted to provide assurance efficiently, but have never been sucessful at eliminating explicit time and space redundancy. One approach is the Application-Oriented Fault Tolerance Paradigm, which provides assurance by examining the behavior and propenies of the application and deriving executable assertions for the detection of faults. Previous work has demonstrated the feasibility of the application-oriented fault tolerance paradigm for various applications. However, the executable assertions were guided by the natural constraints of the problem. This work focuses …

Effects Of Nonsymmetric Release Times On Rate Monotonic Scheduling, R. G. Karl, T. L. Lo, D. C. St. Clair

Computer Science Technical Reports

This paper discusses problems associated with scheduling periodic tasks in a hard, real-time processing or computing environment using a static-priority, preemptive-resume operating system . The scheduling problems associated with a task set containing a single periodic task which has two fixed release periods of unequal length are examined. Some real-world applications may require task release times which are periodic, but whose tasking periods are not symmetric. A scheduling algorithm for task sets with a single nonsymmetric task has been developed for staticpriority, preemptive-resume operating systems. The nonsymmetric scheduling algorithm is based on the rate monotonic scheduling algorithm which assigns higher …

Design Of Backpropagation Neural Network Architectures Using A Decision Tree Classifier, B. M. Van Horn, D. C. St. Clair

Computer Science Technical Reports

The backpropagation neural network algorithm is a popular machine learning methodology. One difficulty with using the algorithm is that the network architecture must be designed before learning can occur. This includes deciding the number of layers, the number of nodes in each layer, and the number of connections. Traditionally this problem is solved by heuristics gained by an expert through experience.

This paper presents an algorithm for using ID3 decision trees to design the network architecture. Previous approaches rely on binary decision trees. The proposed technique utilizes n-ary trees. These trees are easier to understand, are better suited for continuous-valued …

Optimizing Accuracy And Generalization In Numeric Classification Systems, M. D. Walters, D. C. St. Clair

Computer Science Technical Reports

Classifier systems are knowledge-based learning algorithms that take training instances as input and produce a set of rules as output. The classifier systems focused on in this paper represent the knowledge they learn in the form of decision trees, and are built upon Quinlan's [ 1986] inductive algorithm ID3.

The ID3 algorithm suffers from the inability to easily and effectively handle domains with numeric-valued attributes. Numeric attributes are those whose values are taken from a continuous domain or from a domain with a large number of discrete values. A number of approaches have been developed for extending ID3 to handle …