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Computer Sciences

1993

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Articles 31 - 60 of 415

Full-Text Articles in Physical Sciences and Mathematics

Script-Based Qos Specifications For Multimedia Presentations, Richard Staehli, Jonathan Walpole Dec 1993

Script-Based Qos Specifications For Multimedia Presentations, Richard Staehli, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Multimedia presentations can convey information not only by the sequence of events but by their timing. The correctness of such presentations thus depends on the timing of events as well as their sequence and content. This paper introduces a formal specification language for playback of real-time presentations. The main contribution of this language is a quality of service (QOS) specification that relaxes resolution and synchronization requirements for playback. Our definitions give a precise meaning to the correctness of a presentation. This specification language will form the basis for a QOS interface for reservation of operating system resources.

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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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Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall Dec 1993

Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall

Theses and Dissertations

This thesis develops and evaluates a number of new concepts and tools for the analysis of signals using Malvar wavelets lapped orthogonal transforms . Windowing, often employed as a spectral estimation technique, can result in irreparable distortions in the transformed signal. By utilizing the Malvar wavelet, any signal distortion resulting from the transformation can be eliminated or cancelled during reconstruction. This is accomplished by placing conditions on the window and the basis function and then incorporating the window into the orthonormal representation. Paradigms for both a complex-valued and a real-valued Malvar wavelet are summarized. I-lie algorithms for the wavelets were …

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An Analysis Of The Root Causes Of Delays And Deficiencies In The Development Of Embedded Software For Air Force Weapon Systems, Jay R. Hopkins, Curtis De Keyrel Dec 1993

An Analysis Of The Root Causes Of Delays And Deficiencies In The Development Of Embedded Software For Air Force Weapon Systems, Jay R. Hopkins, Curtis De Keyrel

Theses and Dissertations

The importance of embedded software, used in every subsystem of ah major weapon systems used by the United States Air Force, has increased drastically over the last decades. However, in spite of the regulations currently in existence, developing and acquiring software which meets the user requirements within the original cost and schedule estimates continues to be difficult. At the same time, the Air Force has pushed to improve the development process with the Total Quality Management TQM program. The primary method used to improve the process has been to create metrics, collect data on these metrics, and then perform a …

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Design And Construction Of The Aerobot Robotic Manipulator (Arm), William L. Cochran Dec 1993

Design And Construction Of The Aerobot Robotic Manipulator (Arm), William L. Cochran

Theses and Dissertations

This thesis designed, constructed, and tested a robotic arm for the Aerobot Aerial Robot. The main purpose of the ARM is to enable the Aerobot to retrieve objects for use in an annual robotics competition. Design of the ARM involved synthesizing the characteristics of simplicity, weight, strength, and size. The result was a three-degree-of-freedom manipulator that uses electric motors, cable linkages, and telescoping tubes to access a work space below the Aerobot. Forward and inverse kinematics were investigated to enable automation of the ARM. Data was collected from infrared sensors to validate the model. Manipulation of the ARM is presently …

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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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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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Alternative Architectures For Domain-Oriented Application Composition And Generation Systems, Warren E. Gool Dec 1993

Alternative Architectures For Domain-Oriented Application Composition And Generation Systems, Warren E. Gool

Theses and Dissertations

This thesis presents a formalized framework for comparing the structure and semantics of software architectures. The framework uses object diagrams for analyzing the structure of the architectures and the axiomatic approach for analyzing the semantics. This framework is used to compare the Object Connection Update OCU model developed by the Software Engineering Institute against four other software architectures VHDL defined by Lipsett, MetaH defined by Honeywell, microRapide defined by Luckham, and hierarchical software systems as defined by Batory. The goal of the comparison was to evaluate the OCU model for suitability within prototype application composition and generation systems. This research …

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Integration And Enhancement Of The Saber Wargame, Karl S. Mathias Dec 1993

Integration And Enhancement Of The Saber Wargame, Karl S. Mathias

Theses and Dissertations

The Saber wargame is a theater-level air/land battle wargame written in Ada that is being developed for the Air Force Wargaming Center at Maxwell AFB, AL. This thesis documents how the user interface and simulation engine were integrated. Integration was accomplished by developing a portable object-oriented database system (OODBMS) interface. The interface was implemented in Ada and tied to an OODBMS also written in Ada. Using the interface, both subsystems were able to work from a consistent database and exchange information. The user interface was enhanced by converting it from the Software Technology for Adaptable Reliable Systems Ada/X Window System …

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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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Three Dimensional Object Recognition Using A Complex Autoregressive Model, David E. Chelen Dec 1993

Three Dimensional Object Recognition Using A Complex Autoregressive Model, David E. Chelen

Theses and Dissertations

Based on an autoregressive model, Complex Partial Correlation CPARCOR features are known to provide exceptional Position, Scale, and Rotation Invariant PSRI properties for planar 2-Dimensional 2-D object recognition. Although autogressive models have been successfully applied to numerous spatio-temporal recognition tasks, the effects of out-of-plane image rotations were never considered. This study investigates application of the CPAR-COR model to a five class problem of nonplanar 2-D views of 3-D objects. Recognition based on CPAR-COR features is evaluated using a Template Matching algorithm, two K-Nearest-Neighbor KNN classifiers, and a Hidden Markov Model HMM. Direct comparisons to recognition based on Fourier features are …

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Multiple Model Adaptive Estimation Applied To The Lambda Urv For Failure Detection And Identification, David W. Lane Dec 1993

Multiple Model Adaptive Estimation Applied To The Lambda Urv For Failure Detection And Identification, David W. Lane

Theses and Dissertations

Multiple Model Adaptive Estimation (MMAE) is a method of estimating unknown system parameters by modeling all possible parameter configurations in several models. The parameters for this research are failure status conditions associated with flight control actuators and sensors on the LAMBDA Unmanned Research Vehicle, an experimental aircraft operated by Wright Laboratory Flight Controls Division at Wright-Patterson Air Force Base, Ohio. Six actuator failures and eight sensor failures are modeled, along with the fully functional aircraft, in fifteen elemental Kalman filters. These filters propagate and update their own aircraft state estimates in real time. A probability computation representing the likelihood of …

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The Afit Multielectrode Array For Neural Recording And Simulation: Design, Testing, And Encapsulation, James R. Reid Jr Dec 1993

The Afit Multielectrode Array For Neural Recording And Simulation: Design, Testing, And Encapsulation, James R. Reid Jr

Theses and Dissertations

A two-dimensional, X-Y addressable, multiplexed array of 256 electrodes (16 x 16) has been fabricated using conventional semiconductor processing techniques. The individual electrodes are 16O microns x 160 microns, approximating the size of the cortical columns; the overall array size is 3910 microns x 3910 microns. The array has been fitted to a chronically implantable package and tested for several days in a simulated neural environment. EEG-like data were collected successfully from individual electrodes in the array. This array improves on a previous design of a 16 electrode (4 x 4) array that was chronically implanted on the cortex of …

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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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Using Database Technology To Support Domain-Oriented Application Composition Systems, Danny A. Cecil, Joseph A. Fullenkamp Dec 1993

Using Database Technology To Support Domain-Oriented Application Composition Systems, Danny A. Cecil, Joseph A. Fullenkamp

Theses and Dissertations

This research designed and prototyped an OODBMS technology base to store and retrieve various types of domain artifacts for domain-oriented application composition systems (DOACS). We developed object-oriented database schemas for a validating domain and the Object-Connection-Update software architecture. We implemented an inheritance relationship between the schemas so a domain model can inherit an architectural structure from an architecture model allowing us to isolate domain-specific knowledge from architecture-specific knowledge. We also developed a meta-model to formally define domain models in the database. We then developed a set of database methods to transform a domain model into a database schema for storing …

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A Parallel Computational Fluid Dynamics Unstructured Grid Generator, Deborah E. Davis Dec 1993

A Parallel Computational Fluid Dynamics Unstructured Grid Generator, Deborah E. Davis

Theses and Dissertations

This research addressed the development of a parallel computational fluid dynamics unstructured grid generator using Delaunay triangulation. The generator is applied to simple elliptical and cylindrical two-dimensional bodies. The methodologies used included Watsons point insertion algorithm, Holmes and Snyders point creation algorithm, a discretized surface definition, Andersons clustering function, and a Laplacian smoother. The first version of the software involved a processor boundary exchange at the end of each iteration with no inter-processor communications during the iterations The second version used inter-processor communication during each iteration instead of the boundary exchange. Version 1 demonstrated a speedup of 1.8 for some …

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Developing A Sophisticated User Interface To Support Domain-Oriented Application Composition And Generation Systems, Jay A. Cossentine Dec 1993

Developing A Sophisticated User Interface To Support Domain-Oriented Application Composition And Generation Systems, Jay A. Cossentine

Theses and Dissertations

This research refined the visual presentation and usability of a previously developed visual interface for a domain-oriented application composition and generation system. The refined visual interface incorporated domain-specific bit-mapped graphics and sophisticated user interface design concepts to reduce user workload. User workload was reduced through object layout, window design, and color utilization techniques; by combining repetitive procedures into single commands; and reusing, rather than recreating, composition information throughout the application composition process. The Software Refinery environment, including its graphical interface tool INTERVISTA, was used to develop techniques for visualizing and manipulating objects contained in a formal object base. INTERVISTA was …

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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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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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A Numerical Study Of High-Speed Missile Configurations Using A Block- Structured Parallel Algorithm, Douglas C. Blake Dec 1993

A Numerical Study Of High-Speed Missile Configurations Using A Block- Structured Parallel Algorithm, Douglas C. Blake

Theses and Dissertations

A numerical analysis of the aerodynamic phenomena associated with the high-speed flight of a sharp-nosed, four-finned, high-fineness ratio missile using a block-structured, parallel computer algorithm is presented. The algorithm, PANS-3EM, utilizes a second-order-accurate, shock-capturing, Total Variation Diminishing scheme and incorporates a Baldwin-Lomax turbulence model. PANS-3EM allows for extreme flexibility in the choice of computational domain decomposition and computing machine of implementation. Developmental work consists of conceptualization and verification of the algorithm as well as parallel performance and scalability studies conducted on a variety of computing platforms. Using PANS-3EM, the aerodynamic characteristics of the missile are investigated. Drag and pitching moment …

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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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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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A Prototype Architecture For An Automated Scenario Generation System For Combat Simulations, Mark W. Pfefferman Dec 1993

A Prototype Architecture For An Automated Scenario Generation System For Combat Simulations, Mark W. Pfefferman

Theses and Dissertations

This research effort examines the problem of automating the scenario generation process and presents a prototype architecture for an automated scenario generation system. This architecture is designed using an object- oriented approach which leads to a modular and modifiable design. The architecture provides a mechanism for automatically generating scenario files from a textual US Army operation order. This translation process occurs in two phases. First, the text operation order is translated into an intermediate format called the mission file. In the second phase, the system reads the mission file, instantiates intelligent entities, and assigns missions to those entities. The intelligent …

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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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Design Of A Shared Coherent Cache For A Multiple Channel Architecture, John A. Reisner Dec 1993

Design Of A Shared Coherent Cache For A Multiple Channel Architecture, John A. Reisner

Theses and Dissertations

The Multiple Channel Architecture MCA is a recently proposed computer architecture which uses fiber optic communications to overcome many of the problems associated with interconnection networks. There exists a detailed MCA simulator which faithfully simulates an MCA system, however, the original version of the simulator did not cache shared data. In order to improve the performance of the MCA, a cache coherency protocol was developed and implemented in the simulator. The protocol has two features which are significant: (1) a time-division multiplexed TDM communication bus is used for coherency traffic, and (2) the shared data is cached in an independent …

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Objectsim - A Reusable Object Oriented Dis Visual Simulation, Mark I. Snyder Dec 1993

Objectsim - A Reusable Object Oriented Dis Visual Simulation, Mark I. Snyder

Theses and Dissertations

This research designed and implemented a reusable Distributed Interactive Simulation DIS visual simulation architecture for Silicon Graphics platforms. The goal was to research software architecture technologies and to create a design and implementation using these ideas. The architecture was designed using object oriented techniques to provide the ability to customize it via inheritance extension. The resulting design was implemented using C and applied to several DIS visual simulation projects in the Graphics Lab at AFIT. The architecture, named ObjectSim, was successful in its goal of providing a reusable core for the DIS visual simulation projects in the Graphics Lab at …

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A Distributed Interactive Simulation Based Remote Debriefing Tool For Red Flag Missions, Michael T. Gardner Dec 1993

A Distributed Interactive Simulation Based Remote Debriefing Tool For Red Flag Missions, Michael T. Gardner

Theses and Dissertations

Air Force leaders, recognizing the need for improved training following the Vietnam War, implemented the Red Flag exercises at Nellis AFB. At the heart of this training is the Red Flag Measurement and Debriefing System RFMDS and its capability to accurately reconstruct the elements of an intense exercise fought over the deserts of Nevada. This thesis uses the technology of distributed interactive simulation DIS to transmit aircraft telemetry onto computer networks, allowing the monitoring and analysis of live Red Flag missions at any site with compatible communications equipment and thesis software. The use of standard DIS protocols enables simulators to …

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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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