US Navy training commands use a local area and a wide area network known as the Versatile Training System II (VTS). VTS furnishes word processing, electronic mail, and data base functions, all of which can be transferred throughout the network. Enabling this rather old system is a mainframe at each training site with user terminals dispersed throughout the command. The system was installed and is maintained by civilian contractors. VTS does not have the capabilities to develop and maintain curriculum, because advanced word processing and graphics are required. This results in the Navy's training commands having redundant computer systems. Due to the shortcomings of VTS, a need exists to establish local area networks at training commands. Additionally, a wide area network is required that would give a standard package of electronic mail and file transfer capabilities. All of this must be accomplished using existing command computer resources and at a more economical price than the remaining life cycle cost of VTS. To facilitate the design, the systems engineering concept is utilized. A specific design is developed to fill the identified deficiency. Existing resources and "off the shelf" material are to be used exclusively. / Master of Science

Chaotic encryption is currently a popular topic in technical journals. A number of articles have been written proposing novel methods of encrypting data using chaotic signals. Most of the encryption schemes rely on the ability of chaotic systems to be synchronized. Pecora and Carroll, the noted experts on this topic, have published a number of papers describing the theory and presenting simulations of synchronized circuits. Their papers are most often cited as the source of synchronization theory. However, no tests have been performed exploring synchronization across anything but ideal channels. This paper presents a brief background of chaotic signals. The basic theory of synchronizing chaotic signals is covered next. Finally a series of experiments are performed testing the ability of a chaotic signal to synchronize over various audio grade channels, the most often used medium for encrypted information. The experiments show that there are considerable problems getting chaotic circuits to synchronize over non-ideal channels. The failure to synchronize is discussed with respect to each channel tested. A number of additional research opportunities are presented. / Master of Science

Computing in a heterogeneous environment requires an exchange of information among computers which have different ways of representing information. This type of information exchange demands a standard external data representation. One such standard, Abstract Syntax Notation One (ASN.l), is defined by the International Organization for Standardization (ISO) and its transfer syntax, the Basic Encoding Rules (BER). This project presents the design of a C++ class hierarchy modeling the concepts presented in ASN.l and encapsulating the BER encoding rules. The goal of this class hierarchy is to utilize the rich features of object-oriented paradigm to provide a clean and simple interface for OSI presentation layer protocols to application developers and implementors. This report discusses the class hierarchy in detail and shows how the primitive and constructed ASN.l types are defined, encoded and decoded using this hierarchy. / Master of Science

<p>Bar coding is an alternative to manual data collection systems, and it provides the means to collect and report information quickly and accurately. Bar coding is widely used in manufacturing environments to track work-in-process, inventory, time and attendance, documents, capital assets, and product quality. In this project, an integrated data collection system using bar code technology is designed and installed in the Automatic Data Collection System Laboratory (ADCSL), at Virginia Tech. In addition, a series of lab exercises and technology demonstrations are developed to better introduce the technology into the Industrial and Systems Engineering curricula. This can provide engineers choosing this major, the necessary background for making meaningful use of bar coding technology once they graduate.</p> / Master of Science

When heterogeneous computers exchange data over a network, they must agree on a common interpretation of the data. The OSI suite of protocols includes a standard notation, Abstract Syntax Notation One (ASN.1), for describing the structure ("abstract syntax") of data. Previous work has shown that C++ is a good language for work with layered network architectures and specifically with ASN.1: the inheritance and polymorphism features of C++ are nicely suited for work with layered protocols, which can be seen and used in object-oriented terms; a C++ class hierarchy, designed to capture the language concepts of ASN.1, successfully separates the abstract syntax (or application level) from the encoding used during transfer (the "transfer syntax" at presentation level); and the class construct and scoping rules of C++ and the design of the class hierarchy much better preserve the structure and content of ASN.1 than do past attempts with C. This report presents CATV (Class-oriented ASN.1 Translator, Yacc-based), a translator from ASN.1 to a corresponding C++ abstract syntax class hierarchy. It is shown in this report that the translations produced by CATV are preferable to those produced by other translators based on the following criteria: preservation of names and types, consistent access to elements, support of modularity and subtypes, resolution of forward references, flexibility of encoding, and generality of use. Furthermore, it is shown that CATV has better throughput than PEPSY, an ASN.1 to C translator from ISODE. / Master of Science

Accurate predict of ASIC power diss ion is possible using VHDL. By using physical data types, timing and power estimations can be based on estimated typical fan-in and fan-out conditions and a pre-characterized circuit library. Actual load conditions can be back annotated to yield actual power dissipation. Methods to determine pattern sensitive and pattern insensitive power diss ion are presented. This approach uses the concept of load ports VHDL to permit self determining load conditions based on historical wiring data for a given technology. <p>Modeling techniques for VHDL circuit descriptions are developed that allow propagation delay, output rise and fall time, power dissipation be determined from VHDL event simulation. An example of an ALU such as the 74LS181 is presented. / Master of Science

<p>New sapphire fiber based sensor structures for high temperature strain measurement are proposed and studied in this report. The self-mixing interferometry has been studied and tested. The advantage of this technique is the source coherence insensitivity and direction distinguishment capability. Fringes of the self-mixing interferometer built with standard multimode fiber and sapphire fiber were observed. The application of this technique to static strain rneasurement seems difficult to stabilize, whereas its implementation to acoustic sensing with single-mode fiber coil as the sensing component will be very interesting. The approach by Moire interferometry and equal-path coherence matching interferometer are two promising methods for high temperature displacement measurement. The advantages of the Moire interferometer are source coherence independence and large measurement range. The advantage of coherence matching absolute interferometer is its simplicity in sensor structure. The structures of coherence matching methods and multiplexing techniques are generalized. From this research, we can conclude that the sapphire fiber based high temperature extensometer may be realized by different methods.</p> / Master of Science

<p>Use of teleconferencing systems can have a major impact on mobility-impaired office workers. This technology helps in bringing jobs to the workers' geographic 10catioIl, thereby integrating mobility-impaired workers into the work force. However, configuration of teleconferencing systems is difficult, time-consuming, and expensive. The aim of the work reported here was to find an affordaLle and efficient way of configuring teleconferencing systems. In the past, expert systems have been successful in solving similar configuration problems. In this report, an expert system is proposed to aid in the configuration of teleconferencing systems. The report also includes detailed problem specifications, justification for choosing an expert system as a solution, and high-level functional specifications for the development of an expert system.</p> / Master of Science

The primary objective of this research effort was to examine the relationships between successful lodging yield management systems and controllable independent variables in the form of critical success factors (CSFs). The identification of variables consequential to system success is considered to be an important step towards improving system design, implementation, and operation. Twenty-three system success constructs, 27 potential CSFs, and three confounding variables were identified through an extensive literature review, discussions with system vendors, developers, and users, and through data analysis. Eleven different lodging yield management systems (LYMSs) were identified, and three of them were sampled. The dependent variables were converted into a single weighted regression factor score using a principal components model. The respondent's position, size of property, and type of property were found to be confounding variables. The dependent and independent variables were correlated to identifY the CSFs. Every independent variable was identified as a CSF for at least one of the three systems, and the strength of the correlations were generally high. System, user, and task factors were found to be highly correlated to system success. Support and environmental factors were found to be moderately to weakly correlated to system success. / Ph. D.

The paradigm of sustainable development has moved center-stage in the development community and strategies for achieving sustainable development are proliferating. However, the capacity of institutions to support sustainable development in non-industrialized countries has not been adequately addressed. There is a need to solve the sustainable development problem conceptually by linking strategy content and implementation issues with processes of strategy formulation internal to institutions. This study investigated the hypothesis that the dominant "technocratic" approach to strategy formulation, in which development problems are treated as technical, apolitical problems, creates strategies that probably will not implement sustainable development as intended. The World Bank's Strategy for Achieving Sustainable Development in Developing Countries (1992) was applied to the international tourism industry by twenty-five persons from industry, academia, non-government organizations and consultancies to identify implementation issues and problems that might be attributed to use of the technocratic approach. The study found that the World Bank's strategy probably will not implement sustainable development as intended due to fundamental conflicts in assumptions about how sustainable development can and should be achieved. The findings of this study support the argument made in the literature that a change in approach to strategy formulation is required. The findings also suggest that the proposed alternative to the technocratic approach may not be sufficient, because it is little more than a modification of the latter approach and does not resolve the fundamental contradiction between "induced" and "sustainable" development. A more fundamental shift in the values governing development may be required to adapt the modus operandi of development institutions to sustainable development and resolve the value conflicts that continue to diminish the possibility of consensus and action. Although this study provides knowledge of a limited scope, its findings and recommendations may guide an improved perception of the complex problem of identifying requirements for sustainable development and adapting institutions accordingly. / Ph. D.