Digital Commons Network^™

Applications Of Agent Architectures To Decision Support In Distributed Simulation And Training Systems, Plamen V. Petrov

Dissertations

This work develops the approach and presents the results of a new model for applying intelligent agents to complex distributed interactive simulation for command and control. In the framework of tactical command, control communications, computers and intelligence (C₄I), software agents provide a novel approach for efficient decision support and distributed interactive mission training. An agent-based architecture for decision support is designed, implemented and is applied in a distributed interactive simulation to significantly enhance the command and control training during simulated exercises. The architecture is based on monitoring, evaluation, and advice agents, which cooperate to provide alternatives to the …

A Study Of Droplet Burning In The Nearly Adiabatic Limit, Juan C. Gomez

Dissertations

We consider a small drop of liquid fuel that burns in an oxidizing gaseous environment and translates slowly (relative to flow 'at infinity') under the action of gravity. Practical applications include the burning of liquid fuels as sprays in domestic and industrial oil-fired burners, diesel engines, and liquid-propellant rocket motors. More relevant to the simple physical set-up of the present study are wellcharacterized laboratory experiments on the burning of a single, isolated fuel drop.

The drop burns in a nearly spherical, diffusion flame, flame sheet regime. We consider a specific example, or limit, referred to as 'nearly adiabatic burning', in …

Numerical Study Of Particle Dynamics In A Falling-Ball Viscometer, Peiwen Hou

Dissertations

The falling-ball viscometer is a device where a spherical particle falls along the axis of a circular cylinder filled with viscous fluid. The various classical results for this device are developed under the assumption that the Reynolds number of the flow is zero, i.e., Stoke's flow. Inertial effects are not taken into account. To better understand the dynamics of the particle sedimentation process and the role of inertia in this process, we implemented a numerical simulation.

The ADI (Alternating Direction Implicit) scheme is widely used to solve the vorticity-stream function formulation of the Navier-Stokes equation in axisymmetric geometries. However, a …

Interaction Of A Vortex Pair And A Free-Surface : Numerical Simulation, Haisheng Ruan

Dissertations

The interaction between a submerged vortex pair with a deformable free-surface in a viscous, incompressible fluid is directly simulated and the flow is thoroughly analyzed. This is a time-dependent nonlinear free-surface problem which we solve numerically by integrating the two-dimensional Navier-Stokes equations and using boundary-fitted coordinates capable of handling large free-surface deformations. In particular, the numerical simulation of the flow at relatively high Reynolds numbers (Re = 500,1000, 2000 ) and relatively high Froude numbers (Fr = 1. 125, Fr = 2.0) is investigated and analyzed for the first time. Details are given regarding the space-time deformation of …

The Impact And Fate Of Aqueous Sodium Nitrate On Hydrocarbon Flames, Ann Marie Flynn

Dissertations

This study examined the impact and fate of sodium (fed as an aqueous nitrate solution) in fuel-rich methane/air and methane/methyl chloride/air flames as a function of equivalence ratios that experienced diffusion of air from the surroundings. The flames were stabilized on a slotted, uncooled burner. The data set was divided into profiles of relative sodium atom concentrations, temperatures, and selected stable species concentrations. The flames were simulated using a modified version of the Sandia FORTRAN program for modeling steady laminar one-dimensional premixed flames complete with detailed mechanisms. The results showed that maximum sodium atom concentration in the flame is decreased …

Multimedia Modeling Of Organic Contaminants In The Passaic River Watershed, Lansana Coulibaly

Dissertations

A dynamic fate and transport multimedia environmental model was developed and applied to assess the release of five priority contaminants in the Passaic River Watershed, including: napthalene, toluene, trichloroethylene, 1-1-1 trichloroethane and xylene. The model uses the current releases of contaminants as well as cross-boundary advection to determine the fate and environmental distribution of these chemicals in the watershed. The model was developed using a dynamic fugacity approach in order to allow for scenario analysis such as source reductions and no-action alternatives. This modeling effort is expected to achieve a comprehensive assessment of contaminants not only in the proximity of …

Component-Based Software Engineering, Zhiyuan Wang

Dissertations

To solve the problems coming with the current software development methodologies, component-based software engineering has caught many researchers' attention recently. In component-based software engineering, a software system is considered as a set of software components assembled together instead of as a set of functions from the traditional perspective. Software components can be bought from third party vendors as off-the-shelf components and be assembled together.

Component-based software engineering, though very promising, needs to solve several core issues before it becomes a mature software development strategy. The goal of this dissertation is to establish an infrastructure for component-based software development. The author …

Modeling, Design And Fabrication Of Thin-Film Microcrystalline Silicon Solar Cells, Wei Chen

Dissertations

The modeling, design and fabrication of low-cost thin-film microcrystalline silicon(µcSi) solar cells is studied in this thesis. The cell, considered in this investigation, utilizes low-cost glass as the substrate and microcrystalline Si (µc-Si) as the active layer. A comprehensive refractive index (n) and extinction coefficient (k) model of silicon as function of doping, temperature and wavelength is developed to assist the optical design of the cell. In order to obtain acceptable short circuit current density (Jsc) from the cell, it is found that the thickness of the silicon thin film should be more than 10µm. To get the best light …

A Study Of Parental Characteristics And School Choice, Chia-Lin Hsieh

Dissertations

Parental choice of schools has been a hot political issue for more than a decade and has become a cornerstone of federal educational policy. This study investigated the relationship between parental characteristics and school choice, and whether the decision to choose schools is related to family characteristics, school characteristics, parental beliefs, and/or parental satisfaction.

This study used existing national data that were gathered by the National Center for Education Statistics (NCES) and were extracted from the School Safety and Discipline (SS&D) component o f the 1993 National Household Education Survey (NHES:93). 12,680 parents with children in 3rd through 12th grades …

Practitioners’ Perspectives On Alternatives To The Paper-Based System For Preventing Welfare Fraud, Timothy Jerome Cole

Dissertations

Federal agencies have begun to devote greater attention to detecting welfare fraud. This dissertation reviews three proposed alternatives to the current Paper- Based system for preventing welfare fraud, namely, the Paper-Based system with Fingerprint Imaging, Electronic Benefits Transfer (EBT), and EBT with Fingerprint Imaging. It also examines the policy implications likely to result from implementation of these various systems.

Practitioners were randomly selected from agency directories and mailed a survey. Information was sought on their socioeconomic background, professional affiliations, and opinions on several welfare fraud detection systems.

Statistically significant differences in their responses resulted from differences in their socioeconomic backgrounds, …

A Mathematical Model Of Wheelchair Racing, Susan J. Schenk

Dissertations

Wheelchair racing strokes are very complicated movements, which involve a coupling between the athlete and his or her racing chair. Each body segment, as well as the wheel, follows a distinct trajectory as the motion is performed. Understanding the kinematics and kinetics of various stroke techniques would provide the athletes and their coaches with information, which could help guide the racers toward improved performances.

In this thesis, a mathematical model is developed, which is capable of providing such valuable kinematic and kinetic information. This two-dimensional model represents the body segments as a coupled pendulum system of point masses and the …

Experiment, Thermodynamic Properties And Modeling On Combustion Of Methyl Tert-Butyl Ether : Isobutane And Isobutene And Thermodynamic Properties Of Chloro Alkanes And Alkenes, Chiung-Ju Chen

Dissertations

The reaction systems: methyl tert-butyl ether (MTBE) unimolecular decomposition, MTBE radicals + O₂, tert-butyl radical +O₂, isobutene + HOO. (HO₂),isobutene + OH, sobutene-OH adducts + O₂, and allylic isobutenyl radical + O₂, are important systems in the understanding the oxidation chemistry of MTBE, tertiary butyl radical (C3C.), and sobutene, are analyzed. Thermochemical parameters are determined by ah initio Møller-Plesset (MP2(full)/6-31g(d)), complete basis set model chemistry (CBS-4 and CBS-q with MP2(full)/6-31g(d) and B3LYP/6-31g(d) optimized geometries), density functional (B3LYP/631g(d)), semi-empirical MOPAC (PM3) molecular orbital calculations, and by group additivity estimation. Thermochemical …

Development And Application Of Dynamic Models For Predicting Transit Arrival Times, Yuqing Ding

Dissertations

Stochastic variations in traffic conditions and ridership often have a negative impact in transit operations resulting in the deterioration of schedule/headway adherence and lengthening of passenger wait times. Providing accurate information on transit vehicle arrival times is critical to reduce the negative impacts on transit users. In this study, models for dynamically predicting transit arrival times in urban settings are developed, including a basic model, a Kalman filtering model, link-based and stop-based artificial neural networks (ANNs) and Neural/Dynamic (ND) models. The reliability of these models is assessed by enhancing the microscopic simulation program CORSIM which can calculate bus dwell and …

Reconfiguration And Tool Path Planning Of Hexapod Machine Tools, Zhenqun Li

Dissertations

Hexapod machine tools have the potential to achieve increased accuracy, speed, acceleration and rigidity over conventional machines, and are regarded by many researchers as the machine tools of the next generation. However, their small and complex workspace often limits the range of tasks they can perform, and their parallel structure raises many new issues preventing the direct use of conventional tool path planning methods. This dissertation presents an investigation of new reconfiguration and tool path planning methods for enhancing the ability of hexapods to adapt to workspace changes and assisting them in being integrated into the current manufacturing environments.

A …

Collaborative Software Agents Support For The Texpros Document Management System, Jrtian Lin

Dissertations

This dissertation investigates the use of active rules that are embedded in markup documents. Active rules are used in a markup representation by integrating Collaborative Software Agents with TEXPROS (abbreviation for TEXt PROcessing System) [Liu and Ng 1996] to create a powerful distributed document management system. Such markup documents with embedded active rules are called Active Documents. For fast retrieval purposes, when we need to generate a customized Internet folder organization, we first define the Folder Organization Query Language (FO-QL) to solve data categorization problems. FO-QL defines the folder organization query process that automatically retrieves links of documents deposited into …

Polymer Pyrolysis And Oxidation Studies In A Continuous Feed And Flow Reactor : Cellulose, Polystyrene, And Polyethylene, Byung-Ik Park

Dissertations

A dual zone, continuous feed tubular reactor is developed to assessthe potential for formation of products from incomplete combustion in thermal oxidation of common polymers. Solid polymer powder (cellulose,polystyrene, or polyethylene) is fed continuously into a volatilization oven where it fragments and vaporizes under continuous steady state conditions. The gas phase polymer fragments flow directly into a second, main flow reactor oven and undergo further pyrolysis and oxidation reaction. Temperatures in the main flow reactor are varied independently of the volatilization zone to observe conditions needed to convert the initial polymer fragmentsto CO₂ and H₂O. Combustion products …

Multi-User Detection For Multi-Rate Ds/Cdma Systems, Jinwen Ma

Dissertations

Wireless cellular communication is witnessing a rapid growth in market, technology and range of services. Current and future demands for wireless communication services motivate the need for handling multi-media traffic types. In a multimedia communication system, users with different and even time-varying rates and quality of services (QoS) requirements, such as voice, image and data, must be accommodated. The use of Spread Spectrum modulation with Code Division Multiple Access (CDMA) technology is an attractive approach for economical spectrally efficient and high quality cellular and personal communication services. This dissertation explores the technologies of applying different interference cancellation techniques to multi-rate …

Hytexpros : A Hypermedia Information Retrieval System, Hong Shen

Dissertations

The Hypermedia information retrieval system makes use of the specific capabilities of hypermedia systems with information retrieval operations and provides new kind of information management tools. It combines both hypermedia and information retrieval to offer end-users the possibility of navigating, browsing and searching a large collection of documents to satisfy an information need. TEXPROS is an intelligent document processing and retrieval system that supports storing, extracting, classifying, categorizing, retrieval and browsing enterprise information. TEXPROS is a perfect application to apply hypermedia information retrieval techniques. In this dissertation, we extend TEXPROS to a hypermedia information retrieval system called HyTEXPROS with hypertext …

In-Line Measurement Of Solibility Of Physical Blowing Agents In Thermoplastic Melts As Related To Extrusion Foaming, Qiang Zhang

Dissertations

A novel in-line method for measuring physical blowing agent solubility in thermoplastic melts in extrusion foaming equipment has been developed in this study. This method uses video microscopy in connection with a foaming extruder (single or twin-screw) to generate solubility data by observing the onset of gas bubble formation/dissolution. This method offers a number of advantages over the existing conventional methods. It can be easily used to obtain solubility data for many foamable thermoplastic-physical blowing agent systems at high pressure and temperature near actual foaming conditions. Data generated using this method could be directly used to characterize and control a …

Integrated Product And Process Development Methodologies For Environmentally Conscious Electronic Products, Pingtao Yan

Dissertations

This research focuses on integrated product and process development (IPPD) methodologies for environmentally conscious electronic products. After a review of current research issues in the field of product and process development, a generic framework for IPPD is proposed which describes most of the concerned issues formally as constrained optimization problems. These problems may include such optimization objectives as cost, benefit, and environmental impact. Based on this framework, an IPPD methodology is proposed as a systems approach to competitive and environmentally conscious product and process development. A case study on personal computer development is performed illustrating how to apply the methodology …

Data Hiding In Multimedia - Theory And Applications, Mahalingam Ramkumar

Dissertations

Multimedia data hiding or steganography is a means of communication using subliminal channels. The resource for the subliminal communication scheme is the distortion of the original content that can be tolerated. This thesis addresses two main issues of steganographic communication schemes:

1. How does one maximize the distortion introduced without affecting fidelity of the content?

2. How does one efficiently utilize the resource (the distortion introduced) for communicating as many bits of information as possible? In other words, what is a good signaling strategy for the subliminal communication scheme?

Close to optimal solutions for both issues are analyzed. Many techniques …

Experimental And Phenomenological Study Of Persistent Photoconductivity In Yba2cu3o6 Thin Films, Daniel-Dennis Mcalevy Bubb

Dissertations

Persistent Photoconductivity in YBa₂Cu₃O_6+x thin films is studied by means of infrared photoconductivity measurements after the films have been illuminated with visible light at low temperature. Experimentally, the effect is characterized by the samples' electrical response to infrared light, either causing the resistance to decrease or increase.

A cellular automata model is proposed in explanation of these results and is shown to be consistent with current experimental understanding of this unusual effect, both our results and those of others. The cellular automata model may have application to other unusual optical phenomena exhibited by YBa_{2 …}

The Relationships Between Student Diligence, Student Support Systems, Other Related Variables And Student Academic Outcomes In High Schools In Grenada, Christon Arthur

Dissertations

Problem. The Ministry of Education on the Caribbean Island of Grenada has been seeking to find ways to improve students' academic performance. The Ministry's emphasis has been on finding ways to make students more responsible for their education and at the same time trying to examine the level of educator support and parental support students receive. This emphasis on the level of educator and parental support that students receive was due in part to the findings of Hinds et al. (1999) that students in the Eastern Caribbean rate the support from parents and educators as being very important to …

The Current Structure Of Intellect Remediation Lab As An Intervention For Deficient Readers In Grades 3, 4, And 5, Donna Turner Campbell

Dissertations

Problem. Educational testing procedures focus on identification and classification of students rather than on remediation for their abilities. The Structure of Intellect (SOI) model proposes a multidimensional view of intelligence with a focus on remediation for underdeveloped or nonexistent abilities as they relate to school achievement.

Purpose. The purposes of this study were to determine if participation in the SOI remediation lab had a measurable effect on reading achievement with third-, fourth-, and fifth-grade students, and to describe SOI learning profiles of students with below grade reading skills.

Methodology. The subjects for this quasi-experimental study were third-, fourth-, and …

A Cross-Case Study Of Teacher Perceptions Of Program Design And Teaching Efficacy: The Seaview Reading Support Program, Susan L. Bowers Smith Edd

Dissertations

Teachers at Seaview Elementary School developed an innovative reading support program delivered by classroom teachers to increase the achievement of children who struggled to read literature in the district's core curriculum. Although studies of the program's impact on student achievement indicated that many of the children who received services in the classroom were able to fluently read grade level materials and improve their scores on standardized tests, issues created by the additional burden of this instruction on some teachers prevented the integration of the program into other grade levels and schools in the Seaview School District and Seaview Elementary School. …

The Professional Development School : A Descriptive Case Study Of Its History And Development, Denise G. Michaelis

Dissertations

Problem. The development o f school/university partnerships is not a simple process. It requires collaboration between two groups o f professionals who come from different cultures, have developed different forms o f expertise, and operate under different organizational conditions and reward structures (Goodlad, 1990; Stoddart, Winitzky & O ’Keefe, 1992). Throughout much o f the last century, collaboration between schools and universities have often been unsuccessful. In order for Professional Development Schools to be successful in educational reform, it is necessary to focus on defining and delineating the essential characteristics of Professional Development Schools and the process o f their …

An Assessment Of The Perceived Administrative Effectiveness Of Boarding School Principals In The North American Division Of The Seventh-Day Adventist Church, Malcolm E. Hutchinson Jr.

Dissertations

Purpose. The purpose of this study was to examine the views held by those whose duties include the management and day-to-day operations of the secondary boarding schools within the North American Division of the Seventh-day Adventist Church. This refers specifically to superintendents, principals, and staff members

Method. The survey method was used to gather the data. Respondents were asked to complete an 84-item questionnaire. The population sample was made up of 320 staff members, 32 principals, and 31 superintendents. The data were analyzed using mean scores, percentile rankings, and ANOVA at an alpha of p < .05.

Findings. The major findings in …

A Study Of The Out-Of-Class Experiences Of Saint Mary's College Students Studying In Maynooth, Ireland, Carolyn S. Langley

Dissertations

Problem Statement. The purpose of this study is to describe the out-of-class experiences of 21 students who studied in the Saint Mary's College Ireland Program in Maynooth, Ireland, during the 1998-1999 academic year. It examines (1) how the program orientation influenced students' desire to become involved in out-of-class activities, (2) how out-of-class experiences fostered students' learning of the Irish culture, and (3) how the experiences influenced students' attitudes toward cultures other than their own.

Methodology. This study employed descriptive qualitative research. Focus groups were conducted to gather data used in developing questions for long interviews, and these long interviews …

Students' Mental Models Of Electricity In Simple Dc Circuits, Andrew C. Isola Iii

Dissertations

This study presents the results of research into middle school students' knowledge about the nature and mechanisms of action of electricity in simple DC circuits. Sixth, seventh, and eighth graders (n=99) were asked a series of questions about the roles of bulbs, batteries, wires, and electricity in circuits. Almost half the number of students (n=42) were found to have used detailed, well-defined, and logically consistent mental models based on their responses. A total of 15 different detailed mental models were documented in these students that belonged to one of four different general model types: (1) round trip flow using both …

Diagnostic Issues With Attention Deficit Hyperactivity Disorder: Conditional Probabilities And A Measure Of Symptom Ratings, Margo Adams Larsen

Dissertations

Current assessment taxonomy, including the DSM -IV and the International Classification of Diseases (ICD) (World Health Organization, 1990) editions, have provided semistructured criteria sets to aid professionals in making a diagnosis of ADHD or ADD. The diagnostic taxonomy criteria, however, have resulted in a very heterogeneous population of Attention Deficit Hyperactivity Disordered (ADHD) individuals. Several studies have attempted to assess the behavioral syndromes— Attention Deficit Hyperactivity Disorder (ADHD)/Conduct Disorder (CD)/ Oppositional Defiant Disorder (ODD)—in terms of test or symptom sensitivity, specificity, positive predictive power, and negative predictive power (Landau, Milich, & Widiger, 1991; Milich, Widiger, & Landau, 1987; Waldman & …