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1993

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Articles 61 - 90 of 428

Full-Text Articles in Computer Sciences

Using Discovery-Based Learning To Prove The Behavior Of An Autonomous Agent, David N. Mezera Dec 1993

Using Discovery-Based Learning To Prove The Behavior Of An Autonomous Agent, David N. Mezera

Theses and Dissertations

Computer-generated autonomous agents in simulation often behave predictably and unrealistically. These characteristics make them easy to spot and exploit by human participants in the simulation, when we would prefer the behavior of the agent to be indistinguishable from human behavior. An improvement in behavior might be possible by enlarging the library of responses, giving the agent a richer assortment of tactics to employ during a combat scenario. Machine learning offers an exciting alternative to constructing additional responses by hand by instead allowing the system to improve its own performance with experience. This thesis presents NOSTRUM, a discovery-based learning DBL system …

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Developing Realistic Cooperative Behaviors For Autonomous Agents In Air Combat Simulation, Dean P. Hipwell Dec 1993

Developing Realistic Cooperative Behaviors For Autonomous Agents In Air Combat Simulation, Dean P. Hipwell

Theses and Dissertations

This thesis investigated, developed and implemented cooperative decision-making behaviors in an air combat simulation by using a knowledge-based system. Knowledge-based systems were well suited for this task because of built- in features such as inference engines and rule-based constructs. This thesis addresses the specific problem of generating autonomous forces for inclusion in the Advanced Research Projects Agency Distributed Interactive Simulation program. Existing autonomous forces implementations lacked flexibility, realistic behaviors, real-time planning and other features. The simulation system in this thesis addresses the problem of realistic behavior by modeling pilot decision processes rather than aircraft platforms. The system is based on …

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Developing Realistic Behaviors In Adversarial Agents For Air Combat Simulation, George S. Hluck Dec 1993

Developing Realistic Behaviors In Adversarial Agents For Air Combat Simulation, George S. Hluck

Theses and Dissertations

This thesis describes an initial effort into creating a rule-based, reactive system for air combat simulation. This program uses the object-oriented extension of the expert system tool known as the C Language Integrated Production System CLIPS. This effort rose out of the need for creating and integrating semi-autonomous forces for the Distributed Interactive System DIS. This thesis describes the basic maneuvers a pilot uses in present air-to-air combat. The methodology includes the design decisions, knowledge-base development, phase architecture, and maneuver architecture development. The actual implementation of the selected architecture is described. This thesis also discusses the results of experimental runs …

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A Method For Populating The Knowledge Base Of Aptas, A Domain-Oriented Application Composition System, Raleigh A. Sandy Iii Dec 1993

A Method For Populating The Knowledge Base Of Aptas, A Domain-Oriented Application Composition System, Raleigh A. Sandy Iii

Theses and Dissertations

A formal process is described for populating the knowledge base of the Automatic Programming Technologies for Avionics Software APTAS system. This process was developed using a general knowledge base population process that applies to many knowledge-based software engineering systems. This general process is also described. The formal process for APTAS was demonstrated by storing new information from the radar tracking domain into the knowledge base of APTAS. Several procedures some automatic and some manual were implemented to support the formal process.

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Investigation Into Formalization Of Domain-Oriented Parallel Software Development, Daniel P. King Dec 1993

Investigation Into Formalization Of Domain-Oriented Parallel Software Development, Daniel P. King

Theses and Dissertations

This research investigates the conceptual design of a semi-automated platform for parallel software development. The proposed semi-automated environment applies transformational techniques and domain-specific knowledge to a parallel software development process. Domain-specific and software design knowledge interact within the transformational development process in the creation of a software application. The underlying parallel specification language requires a set of parallel composition operators in order to capture an application’s concurrent properties. A set of parallel composition operators is proposed that consists of parallel composition, parallel enumeration, nondeterministic choice, sequential composition specific communication and synchronization variable types are also proposed. A semi-automated environment based …

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Performance Measurement Of Three Commercial Object-Oriented Database Management Systems, Timothy J. Halloran Dec 1993

Performance Measurement Of Three Commercial Object-Oriented Database Management Systems, Timothy J. Halloran

Theses and Dissertations

The goal of this thesis was to study the performance of three commercial object-oriented database management systems. The commercial systems studied included Itasca, sold by Itasca Systems Incorporated Matisse, sold by Intellitic International and ObjectStore, sold by Object Design Incorporated. To examine performance of these database management systems two benchmarks were run the OO1 benchmark and a new AFIT Simulation benchmark. The OO1 benchmark was designed, implemented, and run on all three database management systems. ObjectStore was our top performer on all configurations of the OO1 benchmark. The AFIT Simulation benchmark was designed, implemented, and run on the ObjectStore database …

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Developing A Graphical User Interface To Support A Real-Time Digital Signal Processing System, Jeffrey C. Miller Dec 1993

Developing A Graphical User Interface To Support A Real-Time Digital Signal Processing System, Jeffrey C. Miller

Theses and Dissertations

A graphical software user interface for a VMEbus-based real-time digital signal processing system was designed. Use, requirements were defined and the Rumbaugh object-oriented analysis and design technique was applied to analyze the requirements and produce an object-oriented design. The software design includes a graphical, mouse- and keyboard driven user interface, specialized hardware driver modules, and operating system interfaces. An implementation plan was also developed to map the design into the C programming language using existing system code, automatically generated code, and newly written code. Based on the implementation plan, a limited software system prototype w successfully developed and demonstrated. The …

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Domain Modeling Of Time-Dependent Systems, Robert W. Waggoner Dec 1993

Domain Modeling Of Time-Dependent Systems, Robert W. Waggoner

Theses and Dissertations

This research investigated the feasibility of composing time-dependent specifications in Architect, a domain-oriented application composition and generation system being developed at the Air Force Institute of Technology (AFIT). Architect composes formally specified domain objects into an executable software specification that can be used to verify program correctness prior to generation of language specific code. As part of this research, domain modeling techniques were investigated and a candidate process was selected for evaluation. The process was used to develop domain models for two diverse time-dependent domains. Using object-oriented analysis, formal specifications were developed for a collection of event-driven logic circuit components …

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Domain Analysis And Modeling Of A Model-Based Software Executive, Robert L. Welgan Dec 1993

Domain Analysis And Modeling Of A Model-Based Software Executive, Robert L. Welgan

Theses and Dissertations

This research was adapted the domain analysis techniques of Prieto- Diaz and Tracz to specify a domain analysis process which was used to conduct domain analysis over the domain of software executives. This analysis created a set of informal and formal domain model artifacts. The domain model artifacts were instantiated into two application executive subsystems. These executive subsystems operated in Architect, a domain-oriented application composition system based on the Object-Connection-Update OCU model. This research demonstrated and evaluated execution of the instantiated executive domain model in a series of event-driven and time-driven applications. As a consequence of developing the application executive …

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Investigation Into Model-Based Fuzzy Logic Control, Michael W. Logan Dec 1993

Investigation Into Model-Based Fuzzy Logic Control, Michael W. Logan

Theses and Dissertations

This thesis investigates the feasibility of a proposed hybrid linear/Fuzzy controller for nonlinear plants. The proposed controller concept is based on the use of multiple linearizations of a nonlinear plant, which describe the dynamics of perturbations about equilibrium points throughout the desired envelope of operation. A bank of linear compensators is developed, each corresponding to a linearized plant about a different equilibrium. The multiple control signals generated by the bank of compensators are then weighted and summed using Fuzzy Logic to produce a composite control perturbation signal, which is used to drive the nonlinear plant. Experiments were conducted to test …

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Handwritten Word Recognition Based On Fourier Coefficients, Gary F. Shartle Dec 1993

Handwritten Word Recognition Based On Fourier Coefficients, Gary F. Shartle

Theses and Dissertations

A machine which can read unconstrained words remains an unsolved problem. For example, automatic entry o handwritten documents into a computer is yet to be accomplished. Most systems attempt to segment letters o a word and read words one character at a time. Segmenting a handwritten word is very difficult and often, the confidence of the results is low. Another method which avoids segmentation altogether is to treat each word as a whole. This research investigates the use of Fourier Transform coefficients, computed from the whole word, for the recognition of handwritten words. To test this concept, the particular pattern …

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The Development And Use Of An Evaluation Mechanism For The Assessment Of Software Configuration Management Tools, Wayne M. Descheneau, Neil W. Robinson Dec 1993

The Development And Use Of An Evaluation Mechanism For The Assessment Of Software Configuration Management Tools, Wayne M. Descheneau, Neil W. Robinson

Theses and Dissertations

This study investigated the development of a mechanism for use in the evaluation of Software Configuration Management SCM tools. An examination of applicable DoD standards identified the SCM requirements that could be levied on a development contractor, and a literature search revealed the functionality common to various automated tools. These two sets of information were organized into a matrix, and for each requirement that was met, the intersection on the matrix of the requirement and each functionality used to meet that requirement was checked. In addition to the matrix, the mechanism consisted of general information about a given tool and …

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User-Database Interface: The Effect Of Abstraction Levels On Query Performance, Hock Chuan Chan, Kwok Kee Wei, Keng Siau Dec 1993

User-Database Interface: The Effect Of Abstraction Levels On Query Performance, Hock Chuan Chan, Kwok Kee Wei, Keng Siau

Research Collection School Of Computing and Information Systems

A common classification of data models is based on their abstraction levels: physical, logical and conceptual. The user-database interaction can be similarly classified. For the conceptual-level interaction, the user and the database exchange information on the user's world, e.g., information of entities, relationships, and attributes. For the logical-level interaction, the user and the database communicate based on concepts in the database system, e.g., relations and join operations. We expect users to be familiar with concepts in their world but not the concepts in the database system. This is especially so for infrequent or naive database users. The conceptual level should …

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Universal Wormhole Routing, Ronald I. Greenberg, Hyeong-Cheol Oh Dec 1993

Universal Wormhole Routing, Ronald I. Greenberg, Hyeong-Cheol Oh

Computer Science: Faculty Publications and Other Works

We examine the wormhole routing problem in terms of the "congestion" c and "dilation" d for a set of packet paths. We show, with mild restrictions, that there is a simple randomized algorithm for routing any set of P packets in O(cdη + cLηlog P) time, where L is the number of flits in a packet, and η = min {d,L]; only a constant number of flits are stored in each queue at any time. Using this result, we show that a fat-tree network of area Θ(A) can simulate wormhole routing on any network of comparable area with O(log 3 …

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Parallel Algorithms For Single-Layer Channel Routing, Ronald I. Greenberg, Shih-Chuan Hung, Jau-Der Shih Dec 1993

Parallel Algorithms For Single-Layer Channel Routing, Ronald I. Greenberg, Shih-Chuan Hung, Jau-Der Shih

Computer Science: Faculty Publications and Other Works

We provide efficient parallel algorithms for the minimum separation, offset range, and optimal offset problems for single-layer channel routing. We consider all the variations of these problems that have linear-time sequential solutions rather than limiting attention to the ``river-routing'' context, where single-sided connections are disallowed. For the minimum separation problem, we obtain O(lgN) time on a CREW PRAM or O(lgN/lglgN) time on a CRCW PRAM, both with optimal work (processor-time product) of O(N), where N is the number of terminals. For the offset range problem, we obtain the same time and processor bounds as long as only one side of …

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Vulnerability Assessment Using A Fuzzy Logic Based Method, Richard W. Fleming Dec 1993

Vulnerability Assessment Using A Fuzzy Logic Based Method, Richard W. Fleming

Theses and Dissertations

This thesis demonstrates the feasibility of using qualitative analysis methods to evaluate computer security vulnerabilities. Although many risk analysis systems exist, few provide for the adequate analysis of identified vulnerabilities. While the main focus of this thesis is to evaluate computer security vulnerabilities, the methods involved have application in other areas requiring evaluation using qualitative methods. It is proposed, and demonstrated by this thesis, that the use of qualitative analysis using linguistic variables to describe the impact of computer security vulnerabilities is not only feasible, but intrinsically easier to understand and use than quantitative methods.

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Asynchronous Transaction Commitment In Federated Database Systems, San-Yih Hwang, Ee Peng Lim, Jaideep Srivastava Dec 1993

Asynchronous Transaction Commitment In Federated Database Systems, San-Yih Hwang, Ee Peng Lim, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

We propose a new (and restricted) model for global transactions which allows asynchronous commitment of subtransactions. Our model requires each global transaction to have a fixed structure with update to the data in at most one database. Based on this transaction model, we present two concurrency control algorithms, namely Asynchronous Site Graph and Asynchronous VirtGlobalSG, which employ asynchronous commitment and achieve global serializability. Compared to other proposed algorithms, our algorithms employ asynchronous commitment so as to increase transaction performance. Furthermore, our algorithms do not put restrictions on transaction data access or local histories.

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A Probabilistic Approach To Fault Diagnosis In Linear Lightwave Networks, Robert H. Deng, A. A. Lazar, W. Wang Dec 1993

A Probabilistic Approach To Fault Diagnosis In Linear Lightwave Networks, Robert H. Deng, A. A. Lazar, W. Wang

Research Collection School Of Computing and Information Systems

The application of probabilistic reasoning to fault diagnosis in linear lightwave networks (LLNs) is investigated. The LLN inference model is represented by a Bayesian network (or causal network). An inference algorithm is proposed that is capable of conducting fault diagnosis (inference) with incomplete evidence and on an interactive basis. Two belief updating algorithms are presented which are used by the inference algorithm for performing fault diagnosis. The first belief updating algorithm is a simplified version of the one proposed by Pearl (1988) for singly connected inference models. The second belief updating algorithm applies to multiply connected inference models and is …

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Dynamic Decision Modeling In Medicine: A Critique Of Existing Formalisms, Tze-Yun Leong Dec 1993

Dynamic Decision Modeling In Medicine: A Critique Of Existing Formalisms, Tze-Yun Leong

Research Collection School Of Computing and Information Systems

Dynamic decision models are frameworks for modeling and solving decision problems that take into explicit account the effects of time. These formalisms are based on structural and semantical extensions of conventional decision models, e.g., decision trees and influence diagrams, with the mathematical definitions of finite-state semi-Markov processes. This paper identifies the common theoretical basis of existing dynamic decision modeling formalisms, and compares and contrasts their applicability and efficiency. It also argues that a subclass of such dynamic decision problems can be formulated and solved more effectively with non-graphical techniques. Some insights gained from this exercise on automating the dynamic decision …

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Towards A General Distributed Platform For Learning And Generalization, Brent W. Hughes, Tony R. Martinez Nov 1993

Towards A General Distributed Platform For Learning And Generalization, Brent W. Hughes, Tony R. Martinez

Faculty Publications

Different learning models employ different styles of generalization on novel inputs. This paper proposes the need for multiple styles of generalization to support a broad application base. The Priority ASOCS model (Priority Adaptive Self-organizing Concurrent System) is overviewed and presented as a potential platform which can support multiple generalization styles. PASOCS is an adaptive network composed of many simple computing elements operating asynchronously and in parallel. The PASOCS can operate in either a data processing mode or a learning mode. During data processing mode, the system acts as a parallel hardware circuit. During leaming mode, the PASOCS incorporates rules, with …

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The Importance Of Using Multiple Styles Of Generalization, Tony R. Martinez, D. Randall Wilson Nov 1993

The Importance Of Using Multiple Styles Of Generalization, Tony R. Martinez, D. Randall Wilson

Faculty Publications

There are many ways for a learning system to generalize from training set data. There is likely no one style of generalization which will solve all problems better than any other style, for different styles will work better on some applications than others. This paper presents several styles of generalization and uses them to suggest that a collection of such styles can provide more accurate generalization than any one style by itself. Empirical results of generalizing on several real-world applications are given, and comparisons are made on the generalization accuracy of each style of generalization. The empirical results support the …

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Genetic Algorithms For Soft Decision Decoding Of Linear Block Codes, Harpal Maini, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka Nov 1993

Genetic Algorithms For Soft Decision Decoding Of Linear Block Codes, Harpal Maini, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

Electrical Engineering and Computer Science - Technical Reports

Soft-decision decoding is an NP-hard problem of great interest to developers of communication systems. We show that this problem is equivalent to the problem of optimizing Walsh polynomials. We present genetic algorithms for soft-decision decoding of binary linear block codes and compare the performance with various other decoding algorithms. Simulation results show that our algorithms achieve bit-error-probabilities as low as 0.00183 for a [104, 52] code with a low signal-to-noise ratio of 2.5 dB, exploring only 30,000 codewords, whereas the search space contains 4.5 x 1015 codewords. We define a new crossover operator that exploits domain-specific information and compare it …

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

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

BITs and PCs Newsletter

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

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A Computerized Instructional System For Mechanical Motion Of Objects, Jian J. Zhang Nov 1993

A Computerized Instructional System For Mechanical Motion Of Objects, Jian J. Zhang

Electronic Dissertations and Theses

No abstract provided.

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Object-Oriented Design And Implementation Of A Parallel Ada Simulation System, James T. Belford Nov 1993

Object-Oriented Design And Implementation Of A Parallel Ada Simulation System, James T. Belford

Theses and Dissertations

Simulations which model the behavior real world entities are often large and complex, and require frequent changes to the configuration. This research effort examines the benefits of using object-oriented techniques to develop a distributed simulation environment which supports modularity, modifiability, and portability. The components of the Parallel Discrete Event Simulation PDES environment are identified and modeled using the Rumbaugh modeling technique. From the model, a prototype implementation of a Parallel Ada Simulation Environment PASE is accomplished using Classic Ada. A system interface for the Intel ipsc2 Hypercube was developed to illustrate the concepts of modularity and portability. In addition, the …

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On-Line And Dynamic Shortest Paths Through Graph Decompositions, Hristo N. Djidjev, Grammati E. Pantziou, Christos D. Zaroliagis Nov 1993

On-Line And Dynamic Shortest Paths Through Graph Decompositions, Hristo N. Djidjev, Grammati E. Pantziou, Christos D. Zaroliagis

Computer Science Technical Reports

We describe algorithms for finding shortest paths and distances in a planar digraph which exploit the particular topology of the input graph. An important feature of our algorithms is that they can work in a dynamic environment, where the cost of any edge can be changed or the edge can be deleted. For outerplanar digraphs, for instance, the data structures can be updated after any such change in only $O(\log n)$ time, where $n$ is the number of vertices of the digraph. We also describe the first parallel algorithms for solving the dynamic version of the shortest path problem. Our …

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Parallel Max Cut Approximations, Grammati E. Pantziou, Paul G. Spirakis, Christos D. Zaroliagis Nov 1993

Parallel Max Cut Approximations, Grammati E. Pantziou, Paul G. Spirakis, Christos D. Zaroliagis

Computer Science Technical Reports

Given a graph with positive integer edge weights one may ask whether there exists an edge cut whose weight is bigger than a given number. This problem is NP-complete. We present here an approximation algorithm in NC which provides tight upper bounds to the proportion of edge cuts whose size is bigger than a given number. Our technique is based on the methods to convert randomized parallel algorithms into deterministic ones introduced by Karp and Wigderson. The basic idea of those methods is to replace an exponentially large sample space by one of polynomial size. In this work, we prove …

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Asynchronous Parallel Schemes: A Survey, Eric Jui-Lin Lu, Michael Gene Hilgers, Bruce M. Mcmillin Nov 1993

Asynchronous Parallel Schemes: A Survey, Eric Jui-Lin Lu, Michael Gene Hilgers, Bruce M. Mcmillin

Computer Science Technical Reports

It is well known that synchronization and communication delays are the major sources of performance degradation of synchronous parallel algorithms. It has been shown that asynchronous implementations have the potential to reduce the overhead to minimum. This paper surveys the existing asynchronous schemes and the sufficient conditions for the convergence of the surveyed schemes. Some comparisons among these schemes are also presented.

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Ensuring Relaxed Atomicity For Flexible Transactions In Multidatabase Systems, Aidong Zhang, Marian H. Nodine, Omran Bukhres Nov 1993

Ensuring Relaxed Atomicity For Flexible Transactions In Multidatabase Systems, Aidong Zhang, Marian H. Nodine, Omran Bukhres

Department of Computer Science Technical Reports

No abstract provided.

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Curve Fitting With Cubic A-Splines, Chandrajit L. Bajaj, Guoliang Xu Nov 1993

Curve Fitting With Cubic A-Splines, Chandrajit L. Bajaj, Guoliang Xu

Department of Computer Science Technical Reports

No abstract provided.

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