Digital Commons Network^™

An Account Of Expert Phylogenetic Tree Construction From The Problem-Solving Research Tradition In Science Education, Steven D. Brewer

Dissertations

Content knowledge, strategic knowledge, and forms of knowledge organization used in phylogenetic tree construction are described to account for expert performance. A literature review is used to situate this research with respect to studies of: (a) the teaching of evolution, (b) problem-solving expertise, (c) physics and biology problem solving, and (d) the practice of phylogenetic systematics. Rationales are provided for the development of a computer-based problem-solving environment, model problems, and research problems and methodology.

Each problem consisted of a matrix of coded and polarized phylogenetic data organized by taxa and characters. Four series of research problems were constructed that varied …

Experimental And Analytical Investigation Of Waterjet Cleaning Process, Ping Meng

Dissertations

This doctoral dissertation is concerned with the development of water based cleaning technology required by industry which may substitute the traditional approach based upon the use of various chemical cleansers.

The experimental study involves the waterjet removal of various coatings (rust, oil and epoxy based paints, etc.). Cleaning was carried out under a wide range of operational and geometrical conditions (standoff distance, travel speed, water pressure, diameters of sapphire nozzle and focusing tube, nozzle body type). A new designed spiral nozzle body was tested in this work. The use of surfactant was also investigated. Microscope and SEM surface were used …

Characterization And Fabrication Of A (6h)-Sic As A Piezoresistive Pressure Sensor For High Temperature Applications, Robert Sylvester Okojie

Dissertations

A prototype monolithic 6H-SiC pressure sensor operational up to 350°C, with potential to operate up to 600°C, was batch fabricated and tested. At temperatures higher than 450°C, silicon diaphragms creep under minimal load. To operate beyond 450°C, therefore, the use of 6H-SiC was proposed. However, three key technological issues - fabrication, high temperature metallization, and gage factor characterization - had to be resolved. Since conventional fabrication technology is not applicable to SiC due to its near inert chemistry, photoconductive selectivity techniques to etch the piezoresistors were developed. Techniques to wet etch the cavities in a dark current mode were developed, …

Experimental And Numerical Investigation Of Abrasive Waterjet Polishing Technology, Fenggang Li

Dissertations

The objective of this investigation is the development of the abrasive waterjet (AWJ) based polishing technology. The result of the investigation will assist the implementation of AWJ polishing for manufacturing processes and procedures.

Experimental exploration of AWl polishing involving processing of difficultmachine materials such as Alumina ceramic and stainless steel. Surface improvement due to this processing is evaluated by measuring the roughness of the generated surfaces and examining the microhardness and micro-topography of the surfaces using Scanning Electronic Microscopy (SEM). The surface roughness of 0.3 micron was obtained at samples of ceramic and metal alloys at a reasonable rate using …

The Constant Fracture Angle Model For Cementitious Materials, Suk Ki Kim

Dissertations

Fracture mechanics of concrete has been investigated for the past two decades using linear elastic and nonlinear fracture mechanics concepts. The models proposed so far remain questionable largely due to specimen dependency of the proposed fracture parameters.

In this study, a new approach for modeling the fracture characteristics of concrete and fiber reinforced concrete is proposed. The model depends on the load CMOD relationship rather than the traditional load-deflection principle. Although energy consumed during fracture is definitely a direct function of the load displacement response, it was observed that traditional displacement measurement included an extraneous and erratic portion due to …

Towards Designing A Knowledge-Based Tutoring System : Sql-Tutor As An Example, Gang Zhou

Dissertations

A Knowledge-Based Tutoring System, also sometimes called an Intelligent Tutoring System, is a computer based instructional system that uses artificial intelligence techniques to help people learn some subject. The goal of the system is to provide private tutoring to its students based on their different backgrounds, requests, and interests. The system knows what subject materials it should teach, when and how to teach them, and can diagnose the mistakes made by the students and help them correct the mistakes.

The major objective of this dissertation is to investigate and develop a generic framework upon which we can build a Knowledge-Based …

Emulsion Liquid Membrane Removal Of Arsenic And Strontium From Wastewater : An Experimental And Theoretical Study, Ding-Wei Zhou

Dissertations

The emulsion liquid membrane (ELM) technique has been successfully applied on the removal of arsenic (As) from metallurgical wastewater and the removal of strontium (Sr) horn radioactive wastewater. This study consisted of experimental work and mathematical modeling.

Extraction of arsenic by an emulsion liquid membrane was firstly investigated. The liquid membrane used was composed of 2-ethylhexyl alcohol (2EHA) as the extractant, ECA436OJ as the surfactant, and Exxsol D-8O solvent (or heptane) the diluent. The sulfuric acid and sodium hydroxide solutions were use I as the external and internal phases, respectively. The arsenic removal efficiency reached 92% within 15 minutes in …

Explicit Congestion Control Algorithms For Available Bit Rate Services In Asynchronous Transfer Mode Networks, Ambalavanar Arulambalam

Dissertations

Congestion control of available bit rate (ABR) services in asynchronous transfer mode (ATM) networks has been the recent focus of the ATM Forum. The focus of this dissertation is to study the impact of queueing disciplines on ABR service congestion control, and to develop an explicit rate control algorithm.

Two queueing disciplines, namely, First-In-First-Out (FIFO) and per-VC (virtual connection) queueing, are examined. Performance in terms of fairness, throughput, cell loss rate, buffer size and network utilization are benchmarked via extensive simulations. Implementation complexity analysis and trade-offs associated with each queueing implementation are addressed. Contrary to the common belief, our investigation …

Design, Process And Performance Simulation Of A 360x360-Element Very High Frame Rate Burst-Image Sensor, Guang Yang

Dissertations

A process was developed for fabrication of 360x360-element Very High Frame Rate (VHFR) burst-image sensor on the bases of one-dimensional (1-D) and two-dimensional (2-D) device and process simulations using SUPREM III, SUPREM IV, PISCES IIB and ISE-TCAD software, and the process data provided by the David Sarnoff Research Center. This process includes SiO₂-Si₃N₄ gate dielectric, four-levels of polysilicon, three-levels of metal, eight implants, and requires twenty-one mask levels. The imagers with a 2-cmx2-cm chip size were fabricated at the David Sarnoff Research Center. The VHFR burst-image sensor is capable of capturing images at frame rates …

Pattern Discovery In Sequence Databases : Algorithms And Applications To Dna/Protein Classification, Gung-Wei Chirn

Dissertations

Sequence databases comprise sequence data, which are linear structural descriptions of many natural entities. Approximate pattern discovery in a sequence database can lead to important conclusions or prediction of new phenomena. Traditional database technology is not suitable for accomplishing the task, and new techniques need to be developed.

In this dissertation, we propose several new techniques for discovering patterns in sequence databases. Our techniques incorporate pattern matching algorithms and novel heuristics for discovery and optimization. Experimental results of applying the techniques to both generated data and DNA/proteins show the effectiveness of the proposed techniques.

We then develop several classifiers using …

Global Fuzzy Control Based On Cell Mapping, Tea-Quin Kim

Dissertations

Cell mapping methods can generate global optimal controls for nonlinear dynamic systems. However, the implementation of this approach for on-line control is difficult due to its use of a table-based controller which requires a large amount of memory.

In this dissertation, a cell mapping based systematic method is developed to construct a fuzzy controller to replace the table-based controller for global optimal control of dynamic systems. The method consists of four steps: 1) An optimal control table is generated using a cell mapping algorithm. 2) The cells are linked into trajectories to characterize the optimal dynamic evolution of various cell. …

Development Of A Traffic Safety Index For Urban Intersections, Jae-Hong Kang

Dissertations

Conventional safety analysis focuses on the accident environment at specific locations or a limited segment of highways or arterials, and attempts to identify the effects of accident contributing factors. The development of a safety index in the past was based on a statistical summary for county or statewide areas, using general indicators such as population, number of registered vehicles, vehicle miles traveled and so on. This research effort presents a state-of-the-art procedural analytical approach for the safety analysis of Manhattan intersections that are exposed to a unique urban environment. The computed index provides safety ratings that can identify potential safety …

Knowledge Discovering For Document Classification Using Tree Matching In Texpros, Ching-Song Wei

Dissertations

This dissertation describes a knowledge-based system for classifying documents based upon the layout structure and conceptual information extracted from the content of the document. The spatial elements in a document are laid out in rectangular blocks which are represented by nodes in an ordered labelled tree, called the "layout structure tree" (L-S Tree). Each leaf node of a L-S Tree points to its corresponding block content. A knowledge Acquisition Tool (KAT) is devised to create a Document Sample Tree from L-S Tree, in which each of its leaves contains a node content conceptually describing its corresponding block content. Then, applying …

Integrating Hypertext With Information Systems Through Dynamic Mapping, Jiangling Wan

Dissertations

This dissertation presents a general hypertext model (GHMI) supporting integration of hypertext and information systems through dynamic mapping. Information systems integrated based on this model benefit from hypertext function-alities (such as linking, backtracking, history, guided tours, annotations, etc.) while preserving their own computation capabilities. Although systems supporting integration of hypertext and interface-oriented information systems do exist in hypertext literature, there is no existing model or system effectively supporting integration of hypertext and computation-oriented information systems. GHMI makes its major contributions by both extending and specifying the well-known Dexter Hypertext Reference Model. GHMI extends the Dexter model to overcome its limitations. …

Theory And Design Of Portable Parallel Programs For Heterogeneous Computing Systems And Networks, Ying-Chieh Wu

Dissertations

A recurring problem with high-performance computing is that advanced architectures generally achieve only a small fraction of their peak performance on many portions of real applications sets. The Amdahl's law corollary of this is that such architectures often spend most of their time on tasks (codes/algorithms and the data sets upon which they operate) for which they are unsuited. Heterogeneous Computing (HC) is needed in the mid 90's and beyond due to ever increasing super-speed requirements and the number of projects with these requirements. HC is defined as a special form of parallel and distributed computing that performs computations using …

Development Of A Multivariate Qsar Model To Predict Desorption Of Halogenated Aliphatic Hydrocarbons From Activated Sludge Solids, Sudhi Ranjan Mukherjee

Dissertations

Data collected from different wastewater treatment processes have provided statistically significant evidence that many toxic organic contaminants on EPA's list of priority pollutants concentrate several orders of magnitude greater than influent concentrations in industrial and municipal wastewater sludges. Because of the reversibility of sorption processes, it is possible for sorbed organic compounds to desorb at a later time, hence making disposal of these sludges a potential problem. Although a number of models have been developed to predict sorption parameters, they have all been based on empirically derived descriptors whose validity is seriously compromised by the variation in available data for …

Continuous Monitoring Of Volatile Organic Compounds Using Microtrap Based Gas Chromatographic Systems, Yonghua Xu

Dissertations

Continuous analysis allows a representative portion of a sample to flow continuously through an analytical instrument, which gives analytical information with little or no delay in time. A microtrap is a small diameter tube packed with adsorbents in series. When a gaseous sample containing volatile organic compounds (VOCs) flows through the microtrap, the VOCs can be trapped selectively by adsorbents. Then a pulse of electrical current is applied to the microtrap. This rapid heating results in a desorption that can act as a sharp injection for GC separation. Thus the microtrapped sample is the total amount of VOC present in …

A Full Wave Method For Rough Surface Scattering Using Fictitious Current Distributions, Anthony A. Triolo

Dissertations

Rough surface scattering is a current topic of interest in many diverse fields. But, despite its importance, the two most widely used solution methods, the Kirchhoff and first order perturbation methods, are valid only for a restricted range of surface types. There is a large range of surface statistics for which neither of these theories is valid. There are purely numerical solutions to the problem, i.e., the integral equation technique and FDTD method, but these methods require a prohibitively large amount of computer time and storage space for use in practical applications. A full wave method has been introduced by …

Reduction Of Inertia-Induced Forces In A General Spatial Mechanism, Sahidur Rahman

Dissertations

A computer-aided design procedure has been developed for minimizing the adverse effects of the inertia-induced forces by optimum mass redistribution amongst the links of high speed general spatial linkages. The evaluation of an optimality criterion for the mass redistribution of the mechanism will be carried out with the aid of a quadratic programming technique. This has been found to be successful in minimizing inertia induced forces and torques. The validity of the optimization procedure will be demonstrated by application to one kind of spatial linkage.

No literature has been found on the balancing of a general spatial mechanism, since its …

Discrete Element Modeling Of Dry Granular Material Using A Massively Parallel Supercomputer, David W. Washington

Dissertations

It is the state-of -the-art within Geotechnical Engineering to model soils as systems of particles rather than using the traditional continuum approach. Simulating these systems of particles for geotechnical boundary value problems results in systems which are of necessity large, motivating the application of massively parallel supercomputers. This thesis pursues such an approach.

The following work describes numerical experiments using a Discrete Element Method (DEM) paradigm for soils (Trubal) together with massively parallel computers with Single Instruction Multiple Data (SIMD) architecture. The discrete element method describes the behavior of granular assemblies using the classical mechanics of discrete bodies. The computational …

All The Profound Scenes: Federal Preservation Of Civil War Battlefields, 1861-1990, Mary Munsell Abroe

Dissertations

No abstract provided.

Nursing Faculty Connecting With Students: A Heideggerian Hermenteutical Study, Debra I. Craig Dnsc, Msn, Rn

Dissertations

This study sought to gain an insight into the phenomenon of nursing faculty members connecting with students. Caring has been espoused as a key component of nursing education for many decades. In the last 10 years the terms caring and connecting are commonly found associated with each other, and yet there is no clear definition of connecting. It is important to understand a phenomenon from the point of view of those who are experiencing it. Therefore, a study which asked nursing educators to tell stories of the times they had connected with students was undertaken. Ten nurse educators in the …

The Effect Of Written Information And Reassurance On Patient Satisfaction, Anxiety, And Intent To Return For Emergency Care, June Andrea Dnsc

Dissertations

Patients' satisfaction is one of the primary goals of emergency department (ED) providers today. As emergency departments are overcrowded, stressful environments, anxious patients want to be kept informed. Nurses have the opportunity to meet these needs and possibly influence the patients' perception of the experience and intent to return for future care. This study examined the effects of providing written information and reassurance on patient satisfaction, anxiety, and intent to return for emergency care. The design was a posttest design involving a comparison between the control and three experimental groups. Two hundred and forty patients participated in the study, approximately …

Ethical Decision-Making Among Critical Care Unit Nurses, Mary Ellen Bowen Dnsc, Mn, Rn, Cnaa

Dissertations

The health care business has created complex relationships between consumers and health care institutions. Rising health costs, rationing of health care and medical technology have put critical care unit (CCU) nurses in complex environments where they must face ethical conflict. CCU nurses find themselves ill equipped to make sound decisions concerning ethical dilemmas. Nurses must ensure the patient's choices are respected and honored due to the duties inherent in the nurse-patient relationship. The purpose of this study was to explore the process of ethical decision making (EDM) as it is experienced by CCU nurses. Gaining an understanding of this process …

The Journey From Nonexerciser To Exerciser: A Grounded Theory Study, Keri Kuniyoshi Medina Dnsc, Ms, Rn

Dissertations

The physiological and psychological health benefits of regular physical exercise are well-documented; however, drop-out rates from both supervised and unsupervised exercise remain high. Many potential influences on exercise behavior have been studied, but with largely inconsistent results, making it difficult to identify key targets for intervention. The purpose of this study was to explore the process through which nonexercisers become exercisers, and the contextual factors which affect movement through this process, in order to enable nurses to more successfully assist clients to incorporate exercise into their lifestyles. The exercise experiences of 22 individuals who had successfully made the transition from …

The Relationship Between Principals' Length Of Administrative Experience And Organizational Leadership Behavior In Elementary Schools In Saudi Arabia, Hamad Adbulaziz Alkherb

Dissertations

The study examined educational leadership behaviors among elementary school principals in Qasim region of Saudi Arabia. Seven independent variables using a survey questionnaire among a randomly selected sample from the identified population. Self-reporting elicited, first, critical background information and, second, data concerning 60 specific leadership behavior items important to work issues, critical areas of educational administration, professional relationship situations, and leadership problems ordinarily confronted. Items were grouped according to five categories of twelve items each.

Ninety-six principals or 80% of the survey sample of 120 responded. Focus of the study derived importantly from an extensive and complex review of literature …

Evaluation Of A Home-School-Community Liaison Scheme In Irish Elementary Schools, Sandra Ryan

Dissertations

This dissertation describes an evaluation of a Home-School-Community Liaison scheme in Irish elementary schools. The scheme represented an effort to combat educational failure in areas suffering from social and economic disadvantage associated with poor quality housing, high levels of unemployment, dependence on state aid, and crime. The central aim of the scheme was to increase parents' involvement in their children's education. The evaluation study examined how programs in the scheme were constructed and implemented over a three-year period and monitored specified outcomes of program activity. Methodology included questionnaires, interviews, site visits and observations, and standardized achievement testing.

The scheme generated …

A Comparison Of Youth Living Environment In Small And Large Communities Of Michigan, Huilan Yang

Dissertations

This study compares youth living environment in small and large communities in Michigan. The comparison includes three areas of youth living environment: community environment, financial environment, and educational environment. Community in this study is defined as school district. Data are extracted from an existing database developed by the National Center for Educational Statistics titled School District Data Book (SDDB). Out of 560 Michigan school districts included in SDDB, 370 are used in the data analysis, excluding the Detroit City School District and 189 medium-sized districts. Fifteen variables are selected for comparison, categorized under the three areas of youth environment. The …

Integrating Knowledge And Action: A Study Of Leadership In The Development Of Master's Degree Programs In Liberal Studies, Janet L. Littrell Edd

Dissertations

Master's degree programs in liberal studies (MALS programs) have proliferated in the United States over the past twenty years. Studying the leadership relationships that faculty and administration form during the MALS program development process provides insight into how non-traditional graduate programs may be developed in the future. The purposes of the study were to investigate the development of MALS programs, and to examine the leaders and followers who successfully advanced the MALS program development agenda. The specific objectives of the study were (1) to examine the theoretical bases and curricular frameworks of MALS programs; (2) to explore how individuals and …

Ground Water Movement Through The Highly-Fractured Crystalline Core Of A Large-Scale, Foreland Uplift, Roy Al Gorge Arch, South-Central Colorado, Timothy L. Clarey

Dissertations

The objectives of this study were twofold: ( 1) to examine the well-exposed, basement core of the Royal Gorge arch as a large-scale, field test of ground water flow through a fractured, crystalline, aquifer system; and (2) to devise a method to more accurately determine the direction of maximum aperture of a fractured aquifer through structural and hydrogeologic analysis.

The recognition of a preferred direction of maximum aperture in a fractured aquifer remains an important hydrogeologic consideration because flow through a fracture is proportional to the cube of the aperture width. Previous studies of hydraulic directions using fracture orientation techniques …