Digital Commons Network^™

Virtual Prototyping With Surface Reconstruction And Freeform Geometric Modeling Using Level-Set Method, Weihan Zhang

Doctoral Dissertations

"More and more products with complex geometries are being designed and manufactured by computer aided design (CAD) and rapid prototyping (RP) technologies. Freeform surface is a geometrical feature widely used in modern products like car bodies, airfoils and turbine blades as well as in aesthetic artifacts. How to efficiently design and generate digital prototypes with freeform surfaces is an important issue in CAD. This paper presents the development of a Virtual Sculpting system and addresses the issues of surface reconstruction from dexel data structures and freeform geometric modeling using the level-set method from distance field structure. Our virtual sculpting method …

Densification, Microstructure, And Mechanical Properties Of Zirconium Diboride Based Ultra-High Temperature Ceramics, Sumin Zhu

Doctoral Dissertations

"The first part of this dissertation was aimed at studying the densification of ZrB₂ ceramics by pressureless sintering techniques. Various processes have been applied to coat ZrB₂ powders with polymer precursors, which were used to produce C after charring. After sintering at 1900⁰C, relative density increased of ~70% for uncoated ZrB₂ to >99% for ZrB₂ coated with at least 1.0 wt% C. Thermodynamic analysis suggested that C reacted with and removed oxide impurities (ZrO₂ and B₂O₃) that were present on the ZrB₂ particle surfaces, which promoted densification by minimizing grain coarsening"--Abstract, page iv.

Design And Evaluation Of A Virtual Reality Training System For New Underground Rockbolters, David Nutakor

Doctoral Dissertations

"The need for development of better training techniques for underground rock bolters is signified by the fact that a large number of experienced miners (Baby Boomers) will be retiring soon. This means that there will be very little interface time between the new miners and the experienced miners, which could have been used for training the new inexperienced miners. A new generation of workers (Nexters), who have grown up with computers and video games will replace the Baby Boomers, and the most efficient way to introduce them to the safety and health issues of the mining industry is to use …

Harding University Graduate Catalog 2008-2009, Harding University

Harding Academic Catalogs

Academic catalog for the graduate programs at Harding University.

Harding University Graduate School Of Religion 2008-2009 Catalog, Harding University

Harding Academic Catalogs

Academic catalog for the graduate program in Bible and religion.

Harding University Catalog 2008-2009, Harding University

Harding Academic Catalogs

Academic catalog for the undergraduate programs at Harding University.

Energy Efficient Clustering And Secure Data Aggregation In Wireless Sensor Networks, Julia Albath

Doctoral Dissertations

"Communication consumes the majority of a wireless sensor network's limited energy. There are several ways to reduce the communication cost. Two approaches used in this work are clustering and in-network aggregation. The choice of a cluster head within each cluster is important because cluster heads use additional energy for their responsibilities and that burden needs to be carefully distributed. We introduce the energy constrained minimum dominating set (ECDS) to model the problem of optimally choosing cluster heads in the presence of energy constraints. We show its applicability to sensor networks and give an approximation algorithm of O(log n) for solving …

Energy Efficient Wireless Sensor Network Protocols For Monitoring And Prognostics Of Large Scale Systems, James W. Fonda

Doctoral Dissertations

"In this work, energy-efficient protocols for wireless sensor networks (WSN) with applications to prognostics are investigated. Both analytical methods and verification are shown for the proposed methods via either hardware experiments or simulation. This work is presented in five papers. Energy-efficiency methods for WSN include distributed algorithms for i) optimal routing, ii) adaptive scheduling, iii) adaptive transmission power and data-rate control"--Abstract, page iv.

Modeling And Rendering For Development Of A Virtual Bone Surgery System, Qiang Niu

Doctoral Dissertations

"A virtual bone surgery system is developed to provide the potential of a realistic, safe, and controllable environment for surgical education. It can be used for training in orthopedic surgery, as well as for planning and rehearsal of bone surgery procedures...Using the developed system, the user can perform virtual bone surgery by simultaneously "seeing" bone material removal through a graphic display device, "feeling" the force via a haptic deice, and "hearing" the sound of tool-bone interaction"--Abstract, page iii.

Predicting And Reducing Warranty Costs By Considering Customer Expectation And Product Performance, Naresh Kumar Sharma

Doctoral Dissertations

"This dissertation develops from quality loss function to warranty loss function in which customer expectation is also considered to be a variable. First, Taguchi's quality loss function for the larger-the-better case, which is different from the smaller-the better and nominal-the-best cases, has been assimilated into the other two by introducing a term called the target-mean ratio. Further topics addressed include the implications of a finite target on the classification of LTB characteristics, a new concept of a "Complementary Characteristic", operating window, complexity, and SN ratio based on complexity. A warranty is a buyer's confidence owing to the seller's assurance to …

Stochastic Dynamic Equations, Suman Sanyal

Doctoral Dissertations

"We propose a new area of mathematics, namely stochastic dynamic equations, which unifies and extends the theories of stochastic differential equations and stochastic difference equations. After giving a brief introduction to the theory of dynamic equations on time scales, we construct Brownian motion on isolated time scales and prove some of its properties. Then we define stochastic integrals on isolated time scales. The main contribution of this dissertation is to give explicit solutions of linear stochastic dynamic equations on isolated time scales. We illustrate the theoretical results for dynamic stock prices and Ornstein-Uhlenbeck dynamic equations. Finally we study almost sure …

System And Ic Level Analysis Of Electrostatic Discharge (Esd) And Electrical Fast Transient (Eft) Immunity And Associated Coupling Mechanisms, Jayong Koo

Doctoral Dissertations

"The exposure of electronic circuits to lightning, electrostatic discharge (ESD), electrical fast transients (EFT) or sine wave signals can reveal RF immunity problems. Typical problems include temporary malfunctions or permanent damage of integrated circuits (ICs). In an effort to reproduce those disturbances, a series of electromagnetic compatibility standards has been developed. However, a complete understanding of the root cause of the immunity problems has yet to be established. This dissertation discusses immunity problems in three papers, starting at the system level, via the coupling path into the IC"--Abstract, page iv.

Dynamic Equations With Piecewise Continuous Argument, Christian Keller

Masters Theses

"We extend the theory of differential equations with piecewise continuous argument to general time scales. Linear and quasi-linear systems of functional dynamic equations with alternating retarding and advanced argument will be investigated and conditions for globally asymptotic stability of those systems will be stated and proven. Furthermore, oscillation criteria for linear first-order equations with piecewise continuous argument will be established"--Abstract, page iii.

Manufacturing Of Transparent Composites Using Vacuum Infusion Process, Jason Niles Gallagher

Masters Theses

"Glass is the most commonly used transparent material. However, glass is not suitable where low weight and high strength are required. For many applications there exists a need for mechanically strong composite materials of high optical quality and transparency equivalent to window glass. Glass fiber reinforced transparent composite is a viable solution. Transparency is maintained by precisely matching the refractive index of the matrix with that of the glass fiber. Aircraft canopies and transparent armor can be potential applications for this new class of materials.

In the present work, transparent composites are manufactured using vacuum infusion process. Both rectangular glass …

E-Mentoring Strategies For Cross-Cultural Learning And Community Building, Deborah Lapointe, Carol Richmond, Jennifer Linder-Vanberschot, Charlotte Nirmalani Gunawardena, Kerrin Barret, Marlie Saligumba Cardiff, Jason Skinner

University Libraries & Learning Sciences Faculty and Staff Publications

This paper builds on mentoring practices by describing the strategies and results of cross-cultural group e-mentoring in an inquiry-based online course activity that supported Sri-Lankan faculty as online learners or protégés and higher-education students in their quest for knowledge and community. It focuses on the online e-mentoring experience of eight e-mentors in the United States (master's and doctoral students at the University of New Mexico) who engaged in a three-week-long, cross-cultural problem-solving learning activity using Moodle.

Social And Cultural Diversity In Distance Education, Charlotte Nirmalani Gunawardena, Deborah Lapointe

University Libraries & Learning Sciences Faculty and Staff Publications

With the expansion of global telecommunication networks and the worldwide demand for higher education, distance education has the potential to reach out internationally to enhance learning for diverse learners and increase intercultural awareness and communication. By definition, distance education is borderless (Latchem, 2005), although differences in sociocultural contexts, values and expectations of diverse educational systems and learners may prove to be its greatest challenge (Hanna, 2000). While distance education programs proclaim an international focus with international content and learners, instructional design and methods frequently carry Eurocentric Western bias. Distance educators need to be sensitive to social, cultural and educational differences, …

Dublin Core Metadata Harvested Through Oai-Pmh, Amy S. Jackson, Myung-Ja Han, Kurt Groetsch, Megan Mustafoff, Timothy W. Cole

University Libraries & Learning Sciences Faculty and Staff Publications

The introduction in 2001 of the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) increased interest in and awareness of metadata quality issues relevant to digital library interoperability and the use of harvested metadata to build "union catalogs" of digital information resources. Practitioners have offered wide-ranging advice to metadata authors and have suggested metrics useful for measuring the quality of shareable metadata. Is there evidence of changes in metadata practice in response to such advice and/or as a result of an increased awareness of the importance of metadata interoperability? This paper looks at metadata records created over a six-year period …

Chipimpi, Vulgar Clans, And Lala-Lamba Ethnohistory, Brian Siegel

Anthropology Publications

No abstract provided.

Crossing Borders In Search Of The Mother-Daughter Story: Interdependence Across Time And Distance, Ruth Ann Belknap

College of Nursing Faculty Research and Publications

Although studies have identified the importance of the mother–daughter relationship and of familism in Mexican culture, there is little in the literature about the mother–daughter experience after daughters have migrated to the United States. This study explores relationships between three daughters in America and their mothers in Mexico, and describes ways in which interdependence between mothers and daughters can be maintained when they are separated by borders and distance. Data collection included prolonged engagement with participants, field notes, and tape-recorded interviews. Narrative analysis techniques were used. Findings suggest mother–daughter interdependence remains. Some aspects may change, but the mother–daughter connection continues …

Electromagnetic Modeling Of Distributed Coaxial Cable Crack Sensors In Reinforced Concrete Members, Mei Wang

Masters Theses

"Distributed crack sensors were recently developed with coaxial cables that are composed of inner and outer conductors as well as dielectric layer in between. These sensors were designed based on the change in topology of the cable outer conductor structure under strain effects. Various tests of reinforced concrete (RC) beams and columns indicated that the newly designed sensors are 10~50 times more sensitive than commercial cables to the longitudinal elongation applied on their cable structures. The spatial resolution of the sensors is approximately 50 mm. Limited numerical simulations with the transmission line theory and the finite difference time domain model …

Development Of A Gis-Based Seismic Hazard Screening Tool, Andrew J. Wilding

Masters Theses

"Geotechnical earthquake engineering hazards have consequences that are difficult to mitigate, especially for infrastructure systems with multiple and distributed components. In the last few decades significant progress has been made to provide more accurate and useful methods to evaluate hazards for complex systems. One of these advances involves the application of spatial analysis and geographic information systems (GIS), for not only presenting data as maps, but also providing more practical and usable solutions, such as calculating the hazard potential with spatial distribution. This thesis studies the evaluation of geotechnical earthquake engineering hazards within a GIS environment, using borehole-specific data and …

Co-Optimization: A Generalization Of Coevolution, Travis Service

Masters Theses

"Many problems encountered in computer science are best stated in terms of interactions amongst individuals. For example, many problems are most naturally phrased in terms of finding a candidate solution which performs best against a set of test cases. In such situations, methods are needed to find candidate solutions which are expected to perform best over all test cases. Coevolution holds the promise of addressing such problems by employing principles from biological evolution, where populations of candidate solutions and test cases are evolved over time to produce higher quality solutions...This thesis presents a generalization of coevolution to co-optimization, where optimization …

Asynchronous Nanowire Crossbar Architecture For Manufacturability, Modularity And Robustness, Ravi Bonam

Masters Theses

"This thesis spotlights the dawn of a promising new nanowire crossbar architecture, the Asynchronous crossbar architecture, in the form of three different articles. It combines the reduced size of the nanowire crossbar architecture with the clock-free nature of Null Conventional Logic, which are the primary advantages. The first paper explains the proposed architecture with illustrations, including the design of an optimized full adder. This architecture has an elementary structure termed as a Programmable Gate Macro Block (PGMB) which is analogous to a threshold gate in NCL. The other two papers concentrate on mapping and placement techniques which are important due …

A Time Series Classifier, Christopher Mark Gore

Masters Theses

"A time series is a sequence of data measured at successive time intervals. Time series analysis refers to all of the methods employed to understand such data, either with the purpose of explaining the underlying system producing the data or to try to predict future data points in the time series...An evolutionary algorithm is a non-deterministic method of searching a solution space, and modeled after biological evolutionary processes. A learning classifier system (LCS) is a form of evolutionary algorithm that operates on a population of mapping rules. We introduce the time series classifier TSC, a new type of LCS that …

Fault Propagation Timing Analysis To Aid In The Selection Of Sensors Fro Health Management Systems, Jeremy Johnson

Masters Theses

"Sensor data is processed to assess performance and health of complex systems. Proper sensor selection, placement, and implementation are critical to build an effective health management system. For complex systems in which the timely assessment of the health is desired to avoid expensive consequences of failure, sensor placement is vital. The ability to identify a critical failure early is completely dependent on sensor location within the fault propagation path. A strategy for assessing a sensor suite with respect to timely critical failure detection is presented in this thesis. To illustrate the strategy, Fault Propagation Timing Analysis (FPTA) will be performed …

Carbon Credits And Energy Subsidies In Economic Decision Making For Confined Animal Feedlot Operation Waste Treatment, Taresh Grover

Masters Theses

"Released waste into the environment has always had a societal cost. Current issues with swine waste suggest that improved treatment is needed as agricultural production has become more industry-like and also as we now globally value the mitigation of global warming. The current need for and the economic support of advanced waste treatment has converged for animal agriculture, and now improved waste treatment is possible with concurrent economic benefit through alternative energy and carbon emissions. Recent changes have resulted in renewal of interest in anaerobic digestion (AD) technology with methane capture and energy production. An economic model was constructed to …

Imaging In Karst Terrain Using Electrical Resistivity Tomography, Iana Muchaidze

Masters Theses

"The Missouri Department of Transportation (MoDOT) plans to construct a new intersection between highway 60 and highway 65 to alleviate traffic congestion during peak flow periods. This construction site, which is referred to as the Route 60/65 study site in this thesis, is located on the southeastern side of Springfield, Greene County, Missouri. Bedrock in the study area (Burlington-Keokuk Limestone) is characterized by karstic features such as loosing streams, underground caves, and sinkholes. Prior to the commencement of construction, MoDOT conducted a study of the subsurface conditions in the Route 60/65 study site. The main objective was to identify features, …

Modeling And Measurement Of Thermal Residual Stresses And Isotope Effects On Thermo Physical Properties Of Zrb₂-Sic Ceramics, Michael P. Teague

Masters Theses

"Commercially available finite element modeling software (ABAQUS) was used to investigate the internal residual stresses that develop as a result of cooling from processing temperatures in ZrB₂-SiC ceramics. The size and shape of the SiC particles were varied to evaluate their effect on the residual stresses. Results were compared to experimental data and showed similar trends, where increasing SiC particle size increased tensile stress and also decreased strength. Models were used to analyze benefits of novel shaped SiC inclusions and also better understand the short comings of the composites. An attempt to validate the models using neutron diffraction to measure …

Human Systems Integration: Training And Education Needs Analysis, Hao Zhang

Masters Theses

"Over the past decade, the military (both US and foreign) has developed a wide range of tools, techniques, and technologies for integrating human factors into systems engineering. Human Systems Integration (HSI) came forth as a new multidisciplinary field of study composed of several basic areas including Human Factors Engineering, System Safety, Health Hazards, Personnel Survivability, Manpower, Personnel, Training, and Habitability. An online survey was designed to examine education and training in HSI. 19 HSI experts responded to the survey. The feedback showed that there is a lack of high qualified practitioners in HSI. Many HSI practitioners are lacking of required …

Textural Analysis Of A Rhyolite Dike Of The Southern Oklahoma Aulacogen At Medicine Park, Oklahoma, Sean Patrick O'Donnell

Masters Theses

"Detailed analysis of the modal abundance and crystal size distribution (CSD) of glomerocrystic quartz and alkali feldspar phenocrysts in a porphyritic "rhyolite" dike at Medicine Park, Oklahoma were integrated with known phase relationships in the system SiO₂-NaAlSi₃O₈-KAlSi₃-O₈-H₂O to constrain the history of this intrusion"--Abstract, page iv.