Digital Commons Network^™

A Semantic-Based Middleware For Multimedia Collaborative Applications, Agustin Jose Gonzalez

Computer Science Theses & Dissertations

The Internet growth and the performance increase of desktop computers have enabled large-scale distributed multimedia applications. They are expected to grow in demand and services and their traffic volume will dominate. Real-time delivery, scalability, heterogeneity are some requirements of these applications that have motivated a revision of the traditional Internet services, the operating systems structures, and the software systems for supporting application development. This work proposes a Java-based lightweight middleware for the development of large-scale multimedia applications. The middleware offers four services for multimedia applications. First, it provides two scalable lightweight protocols for floor control. One follows a centralized model …

An Object-Oriented Algorithmic Laboratory For Ordering Sparse Matrices, Gary Karl Kumfert

Computer Science Theses & Dissertations

We focus on two known NP-hard problems that have applications in sparse matrix computations: the envelope/wavefront reduction problem and the fill reduction problem. Envelope/wavefront reducing orderings have a wide range of applications including profile and frontal solvers, incomplete factorization preconditioning, graph reordering for cache performance, gene sequencing, and spatial databases. Fill reducing orderings are generally limited to—but an inextricable part of—sparse matrix factorization.

Our major contribution to this field is the design of new and improved heuristics for these NP-hard problems and their efficient implementation in a robust, cross-platform, object-oriented software package. In this body of research, we (1) examine …

On The Validity Of Digital Signatures, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

An important feature of digital signatures is to serve as non-repudiation evidence. To be eligible as non-repudiation evidence, a digital signature on an electronic document should remain valid until its expiry date which is specified by some non-repudiation policy. As signature keys may be compromised and the validity of signatures may become questionable, additional security mechanisms need to be imposed on digital signatures. This paper examines the mechanisms for maintaining the validity of digital signatures, and provides a guideline on the use of these mechanisms in various context of applications.

A Generic Object-Oriented Server Model, Brian Douglas Jones

Electrical & Computer Engineering Theses & Dissertations

The purpose of this paper is to introduce a generic, object-oriented model for the simulation of networks of queues. Generic simulation modeling provides robust ways of laying out processes in stochastic, event driven simulations. The approach taken is to define a methodology that will be implementation independent, termed the Generic Server Simulation Model (GSSM); thus, leaving the implementers to choose the best (most suited for their use) means of implementation. GSSM uses many object-oriented concepts to provide its basic structure and has in its design the ability to take advantage of these object-oriented concepts, including reuse of (existing) code. GSSM …

A Formal Semantics For Spki, Jon Howell, David Kotz

Computer Science Technical Reports

We extend the logic and semantics of authorization due to Abadi, Lampson, et al. to support restricted delegation. Our formal model provides a simple interpretation for the variety of constructs in the Simple Public Key Infrastructure (SPKI), and lends intuition about possible extensions. We discuss both extensions that our semantics supports and extensions that it cautions against.

Web Frauds And Possible Solutions, Hemant Joshi

IIMB Management Review

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 16, Number 3, March 2000, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Extensible Markup Language As A Weather Tool, Michael J. Calidonna

Theses and Dissertations

This thesis is a proof of concept work that will extend the Core Mapping Application Program Interface (CMAPI) components to include weather data. The CMAPI project is headed by Air Force Research Lab (AFRL)/Information Directorate Information Handling Branch (IFEB) at Rome labs in Rome, New York. This work extends the CMAPI project in two distinct areas. The first goal is to figure out how to overlay and display weather data on a dynamically linked Internet platform. This was accomplished by incorporating existing data from the Air Force Weather Agency (AFWA) into the CMAPI program in a static environment. The other …

A Formal Methodology And Technique For Verifying Communication Protocols In A Multi-Agent Environment, Timothy H. Lacey

Theses and Dissertations

As network bandwidth increases, distributed applications are becoming increasingly prevalent. Systems using these applications are very complicated to build and must be dependable. Software agents are ideal for breaking complicated problems into manageable subtasks. Agent conversations, a series of messages passed between agents, are the cornerstone of multi-agent systems and must be deemed correct before being placed into service. The purpose of this research was to develop a formal methodology and technique to verify that the communication protocols defined in a multi-agent environment were valid. This was accomplished by examining agent conversations before deploying the system. An additional goal of …

Stochastic Modeling-Based Dgps Estimation Algorithm, James T. Broaddus

Theses and Dissertations

A Kinematic Differential Global Positioning System (KDGPS) algorithm is developed. A number of mobile receivers is considered, one of which will be designated the reference station' which will have known position and velocity information at the beginning of the time interval examined. Satellite clock biases are used to model Selective Availability. The measurement situation on hand is properly modeled and a centralized estimation algorithm processing several epochs of data. The effect of uncertainty in the reference receiver's position and the level of receiver noise is examined. Monte Carlo simulations are performed to examine the ability of the algorithm to correctly …

An Object-Oriented Repository-Based Software Synthesis System, Gary L. Cornn Jr.

Theses and Dissertations

This research provides a repository on which various Air Force Institute of Technology (AFIT) transformational software synthesis tools can store, share, and manage data using a common repository information model. This information model was created by integrating a variety of separately developed AFIT software synthesis object models into a "wide-spectrum" model. Additionally, a methodology for describing complex relationships between artifacts in the repository is described. These relationships can be used to relate software synthesis artifacts created in a variety of formats, including text, binary, and the AFIT Wide-Spectrum Object Modeling Environment (AWSOME) information model. The relationships can be exploited for …

An Information Visualization Solution For The Analysis Of The Afm Simulation Output Data, Stuart H. Kurkowski

Theses and Dissertations

With the advancement of computer hardware and software computer simulations are now able to run faster and track more elements than ever before burdening the analyst with more and more data to analyze. Air Mobility Command's (AMC) Airlift Flow Model (AFM) is the Air Force's logistics simulator that simulates multi-day mobility scenarios in a matter of minutes producing megabytes of output data. Because the analysts' needs for summaries, trends, and comparisons of the data have surpassed the capabilities of current desktop spreadsheet analysis techniques new tools are needed.

A Human-Centered Approach For Designing Decision Support Systems, Sean G. Kern

Theses and Dissertations

The choice to include the human in the decision process affects four key areas of system design: problem representation, system analysis and design, solution technique selection, and interface requirements specification. I introduce a design methodology that captures the necessary choices associated with each of these areas. In particular I show how this methodology is applied to the design of an actual decision Support system for satellite operations scheduling. Supporting the user's ability to monitor the actions of the system and to guide the decision process of the system are two key considerations in the successful design of a decision support …

A Component Based Approach To Agent Specification, David J. Robinson

Theses and Dissertations

The Air Force, as well as all of industry, is currently faced with the problem of having to produce larger and more complex software systems that run efficiently and reliably as well as being extensible and maintainable. This research addresses this problem by developing a knowledge representation language that can be used to unambiguously specify and design software systems in a verifiable, efficient, and understandable manner. The language is a combination of object-oriented and component-based methodologies and makes use of both graphics and text to represent information. Although designed for the development of any type of software system, the language …

A Method Of Focusing The Attention Of The Decision-Maker On Uncertain Information, John F. Moesner Iv

Theses and Dissertations

Military decision-makers need to be able to synthesize large amounts of information quickly and make accurate and timely decisions. However, all too often, when a decision-maker is bombarded with important information that has an uncertainty associated with it, that information is often neglected. One method of dealing with this type of information overload is through proper data orientation. By reducing the clutter of irrelevant information, the proportions of useful and relevant data can be increased. At the same time, the attention of the decision-maker is directed to the critical tasks or centers of gravity. The WATCHDOG Decision Support Tool is …

Knowledge Base Support For Design And Synthesis Of Multi-Agent Systems, Marc J. Raphael

Theses and Dissertations

AgentTool is an AFIT-produced, AFOSR-sponsored multi-agent system (MAS) development tool intended for production of MASs that meet military requirements. This research focuses on enabling MAS design and synthesis tools like agentTool to store, retrieve, and filter persistent, reusable, and reliable agent domain knowledge. This "enabling" is vital if such tools are expected to produce consistent, maintainable, and verifiable agent applications on short timetables. Enabling requires: 1) modeling the agent knowledge domain, 2) designing and employing a persistent knowledge base, and 3) bridging that domain model to the knowledge base with an extensible domain interchange grammar. The achieved interchange grammar, called …

Enhancing A Virtual Distributed Library User Interface Via Server-Side User Profile Caching, Jason T. Ward

Theses and Dissertations

Various Department of Defense (DoD) agencies archive terabytes of intelligence imagery and electrooptical signature data. The Air Force Research Laboratory, Sensors Directorate (AFRL/SN), is tasked with creating and managing a virtual distributed library that facilitates secure, detailed queries across these distributed holdings using the internally developed Advanced Query Tool (AQT). In this research, a methodology is proposed to utilize user profiling techniques to augment a digital library. As part of this methodology, product-oriented usability analysis metrics are introduced that quantitatively verify the usability of an interface. The methodology is applied to the AFRL/SN's Virtual Distributed Laboratory AQT and subsequently analyzed …

Improving The Analyst And Decision-Maker’S Perspective Through Uncertainty Visualization, Evan T. Watkins

Theses and Dissertations

This thesis constructs the Taxonomy of Uncertainty and an approach for enhancing the information in decision support systems. The hierarchical categorization of numerous causes for uncertainty defines the taxonomy, which fostered the development of a technique for visualizing uncertainty. This technique is fundamental to expressing the multi-dimensional uncertainty that can be associated with any object. By including and intuitively expressing uncertainty, the approach facilitates and enhances intuition and decision-making without undue information overload. The resulting approach for enhancing the information involves recording uncertainty, identifying the relevant items, computing and visualizing uncertainty, and providing interaction with the selection of uncertainty. A …

Explicitly Modeling Hierarchically Heterogeneous Software Architectures In An Object-Oriented Formal Transformation System, Darin L. Williams

Theses and Dissertations

Formal software transformation systems are software development environments typified by the semi-automated application of a series of correctness-preserving transformations to formal data models. The range of software architectures such systems are capable of producing is often restricted by the limited ability to accept high-level design inputs as constraints on the transformation process. When architectural inputs are acceptable, often the modeling language excludes the explicit representation of architectural constructs and provides, at best, an extremely limited architectural analysis capability. This research defines a high-level taxonomy of software architectures and proposes a way to explicitly model a broad class of architectures by …

Multiagent Systems Engineering: A Methodology For Analysis And Design Of Multiagent Systems, Mark F. Wood

Theses and Dissertations

This thesis defines a methodology for the creation of multiagent systems, the Multiagent Systems Engineering (MaSE) methodology. The methodology is a key issue in the development of any complex system and there is currently no standard or widely used methodology in the realm of multiagent systems. MaSE covers the entire software lifecycle, starting from an initial prose specification, and creating a set of formal design documents in a graphical style based on a formal syntax. The final product of MaSE is a diagram describing the deployment of a system of intelligent agents that communicate through structured conversations. MaSE was created …

Generating Executable Persistent Data Storage/Retrieval Code From Object-Oriented Specifications, Steven R. Buckwalter

Theses and Dissertations

This research creates a methodology and corresponding prototype for the transformation of object-oriented (OO) specifications to represent the corresponding relational schemas that are used to automatically generate database design language (DDL). The transformation design decisions and specifications are then used to generate database manipulation language (DML) that can be embedded within the software application code generated from the same OO specifications. This concept of developing a model for producing compilable and executable code from formal software specifications has long been a goal of software engineers. Previous research at the Air Force Institute of Technology (AFIT) has not focused on the …

Extracting Mission Semantics From Unmanned Aerial Vehicle Telemetry And Flight Plans, Walter T. Berridge

Theses and Dissertations

With the acceptance of Unmanned Aerial Vehicles (UAVs) as a primary platform within the Department of Defense (DOD) for gathering intelligence data, the amount of video information being recorded, analyzed, and archived continues to grow. Mechanisms for quickly locating and retrieving video segments of interest amongst the many hours of recorded video are required to accommodate the rapid turnaround expected in today's wartime planning environments. This research demonstrates that text-based data accompanying UAV video yields sufficient information to identify and create data items that can be indexed to provide for rapid identification and retrieval of video segments of interest. Four …

Global Positioning System (Gps) Error Source Prediction, Marcus G. Ferguson

Theses and Dissertations

With the initiation of the navigation accuracy prediction algorithm used to estimate the amount of GPS solution (location and time) error for receivers, the capability to accurately predict solution errors due to the major GPS error sources is growing. Although some sources of error within the GPS solution have been previously analyzed, modeled, and/or accounted for within various modeling efforts, a formal evaluation of the seven major error sources that distort GPS activity has not been officially conducted up until this point. This research offers a logical assessment of all the major GPS error sources and their definitive impact on …

Distributed Object System Engineering For Terminal Aerodrome Forecast Validation And Metrics Processing, James S. Douglas

Theses and Dissertations

Distributed object systems are a very complex intertwining of heterogeneous hardware, software, and operating systems coupled with communication networks of varying protocols and capacities. Distributed components offer improved performance through parallel processing, improved expansion and scalability opportunities through modularity, improved availability through replication, and improved resource sharing and interoperability through interconnection. This research provides a distributed system design methodology to validate terminal forecasts and gather metrics for the Air Force Weather Agency. Proven principles such as component reuse and architectural development are applied through the use of parameterized types and design patterns. A client/server measurement model is developed to show …

Three-Dimensional Data Visualization Of Electronic Military Intelligence Using The Project Broadsword System, Michael L. Goeringer

Theses and Dissertations

Today's military electronic infrastructure solves many problems while creating others. Using computers, battlefield and global awareness is brought to bear through the near real-time linking of sensor platforms from around the globe. These intelligence networks produce vast amounts of data that must be parsed, interpreted, digested and stored by information gathering systems. As the amount of intelligence data continues to increase, these text-based systems become cumbersome and inadequate. To ensure vital information is not overlooked or discovered too late, other forms of intelligence product management and data navigation need to be investigated. This thesis explores procedures for enhancing the capabilities …

A Distributed Agent Architecture For A Computer Virus Immune System, Paul K. Harmer

Theses and Dissertations

Information superiority is identified as an Air Force core competency and is recognized as a key enabler for the success of future missions. Information protection and information assurance are vital components required for achieving superiority in the Infosphere, but these goals are threatened by the exponential birth rate of new computer viruses. The increased global interconnectivity that is empowering advanced information systems is also increasing the spread of malicious code and current anti-virus solutions are quickly becoming overwhelmed by the burden of capturing and classifying new viral stains. To overcome this problem, a distributed computer virus immune system (CVIS) based …

A Java Universal Vehicle Router In Support Of Routing Unmanned Aerial Vehicles, Robert W. Harder

Theses and Dissertations

Unmanned Aerial Vehicles (UAVs) help the military gather information in times of peace and war. During a mission, typically 100 sites or more, a UAV will frequently be re-tasked to visit a pop-up threat, leaving the operator to determine the best way to finish the day's list of sites after the re-tasking. I develop a prototype application to serve the needs of a specific customer, the 11th Reconnaissance Squadron, by helping them preplan missions and dynamically re-task UAVs. This prototype application is built on a reusable airframe router called the core AFIT Router, which can later be added to more …

An Intelligent User Interface To Support Air Force Weather Product Generation And Automated Metrics, Darryl N. Leon

Theses and Dissertations

Air Force pilots require dependable weather reports so they may avoid unsafe flying conditions. In order to better gauge the accuracy of its weather products, Air Force Weather has established the requirement for an Air Force-wide automated weather metrics program. Under the guidelines for this program, forecasts will automatically be compared to observed weather to determine their accuracy. Statistics will be collected in the hopes of determining forecast error trends that can be corrected through education and training. In order for the statistical data produced by such a program to draw reliable conclusions about forecast accuracy, however, the correct format …

Formal Object State Model Transformations For Automated Agent System Synthesis, David W. Marsh

Theses and Dissertations

Automated agent system synthesis is the process of generating code from a requirements specification with appropriate inputs from the software engineer. Object-oriented (OO) specifications are frequently used to model intelligent software agent systems and software requirements in general; formal representations capture precisely the intentions of the specifier. Portions of OO specifications can be classified as the structural, functional, and state (or dynamic) models; major strides have been taken in the development of transformations for creating code from formal OO specifications, specifically the structural and functional aspects, and are captured within the AFIT Wide-Spectrum Object Modeling Environment (AWSOME). This research creates …

The Bond Agent System And Applications, Ladislau Boloni, Kyungkoo Jun, Krzysztof Palacz, Radu Sion, Dan C. Marinescu

Department of Computer Science Technical Reports

No abstract provided.