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 Collection: UNT Theses and Dissertations
Modeling Infectious Disease Spread Using Global Stochastic Field Simulation

Modeling Infectious Disease Spread Using Global Stochastic Field Simulation

Date: August 2006
Creator: Venkatachalam, Sangeeta
Description: Susceptibles-infectives-removals (SIR) and its derivatives are the classic mathematical models for the study of infectious diseases in epidemiology. In order to model and simulate epidemics of an infectious disease, a global stochastic field simulation paradigm (GSFS) is proposed, which incorporates geographic and demographic based interactions. The interaction measure between regions is a function of population density and geographical distance, and has been extended to include demographic and migratory constraints. The progression of diseases using GSFS is analyzed, and similar behavior to the SIR model is exhibited by GSFS, using the geographic information systems (GIS) gravity model for interactions. The limitations of the SIR and similar models of homogeneous population with uniform mixing are addressed by the GSFS model. The GSFS model is oriented to heterogeneous population, and can incorporate interactions based on geography, demography, environment and migration patterns. The progression of diseases can be modeled at higher levels of fidelity using the GSFS model, and facilitates optimal deployment of public health resources for prevention, control and surveillance of infectious diseases.
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Modeling of land use change effects on storm water quantity and quality in the City of Carrollton and the North Texas Area.

Modeling of land use change effects on storm water quantity and quality in the City of Carrollton and the North Texas Area.

Access: Use of this item is restricted to the UNT Community.
Date: December 2003
Creator: Duncan, Phillip Brent
Description: Development and population are rapidly increasing in urbanizing areas of North Texas and so is the need to understand changes in storm water runoff flow and its contamination by nutrients, sediment, pesticides and other toxicants. This study contributes to this understanding and has two primary components: first, development of a graphical user interface for a geographic information system and storm water management database, and second, performing a two-scale hydrological modeling approach (the US Corp of Engineers HEC-HMS model and the US Environmental Protection Agency SWMM model). Both primary components are used together as a toolkit to support the storm water management program of the City of Carrollton, located in North Texas. By focusing limited city resources, the toolkit helps storm water managers in the process of compliance with federal regulations, especially the National Pollution Discharge Elimination System permit, and provides guidance for reporting, planning and investigation. A planning example was conducted by modeling potential changes in storm water quality due to projections of land use based on the City of Carrollton's Comprehensive Plan. An additional component of this study is the evaluation of future changes in surface water quantity and quality in the North Central Texas area, specifically in a ...
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Modeling Place Vulnerability of HIV/AIDS in Texas

Modeling Place Vulnerability of HIV/AIDS in Texas

Date: August 2011
Creator: Harold, Adam F.
Description: This study provides a measurable model of the concept of place vulnerability for HIV/AIDS that incorporates both community and structural level effects using data provided at the ZIP code level from the Texas Department of State Health Services. Sociological literature on the effects of place on health has been growing but falls short of providing an operational definition of the effects of place on health. This dissertation looks to the literature in medical/health geography to supplement sociology’s understanding of the effects of place on health, to the end of providing a measurable model. Prior research that has recognized the complexity of the effects of place still have forced data into one scale and emphasized individual-level outcomes. A multilevel model allows for keeping the associated spatial unit data, without aggregating or parsing it out for convenience of model fit. The place vulnerability model proposed examines how exposure, capacity and potentiality variables all influence an area’s HIV/AIDS count. To capture the effects of place vulnerability at multiple levels, this dissertation research uses a multilevel zero-inflated poisson (MLZIP) model to examine how factors measured at the ZIP code and county both affect HIV/AIDS counts per ZIP code as an outcome. Furthermore, empirical Bayes ...
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Modeling Student Perception of Web 2.0 Technologies Adoption in Kuwait

Modeling Student Perception of Web 2.0 Technologies Adoption in Kuwait

Date: May 2011
Creator: Alajmi, Mohammad
Description: The primary focus of this dissertation was to explore students' perceptions of adopting Web 2.0 applications at the School of Basic Education (SBE) in Kuwait. Although Web 2.0 applications are becoming more popular among the digital generation, there is still no evidence of students' perceptions of adopting the innovation of Web 2.0 technologies in Kuwait. The problem this study addresses is that the current status of Web 2.0 technologies usage by academic students has remained educationally unknown in Kuwait. Therefore, there was a need to investigate the extent to which academic students in SBE are aware of and their usage of Web 2.0 technologies, as well as the factors and obstacles that affect using these technologies. Rogers' diffusion of innovation theory (DoI) is employed in this study to specify the factors that influence student perceptions of adopting Web 2.0 applications as learning tools. Data used in this dissertation was gathered via a survey instrument from 350 students at the SBE and was statistically analyzed to find out the answers of the research questions. This study identified the low rate of Web 2.0 awareness and adoption by the students. Descriptive statistical analysis, such as mean scores and standard deviation, were used ...
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Modeling Synergistic Relationships Between Words and Images

Modeling Synergistic Relationships Between Words and Images

Date: December 2012
Creator: Leong, Chee Wee
Description: Texts and images provide alternative, yet orthogonal views of the same underlying cognitive concept. By uncovering synergistic, semantic relationships that exist between words and images, I am working to develop novel techniques that can help improve tasks in natural language processing, as well as effective models for text-to-image synthesis, image retrieval, and automatic image annotation. Specifically, in my dissertation, I will explore the interoperability of features between language and vision tasks. In the first part, I will show how it is possible to apply features generated using evidence gathered from text corpora to solve the image annotation problem in computer vision, without the use of any visual information. In the second part, I will address research in the reverse direction, and show how visual cues can be used to improve tasks in natural language processing. Importantly, I propose a novel metric to estimate the similarity of words by comparing the visual similarity of concepts invoked by these words, and show that it can be used further to advance the state-of-the-art methods that employ corpus-based and knowledge-based semantic similarity measures. Finally, I attempt to construct a joint semantic space connecting words with images, and synthesize an evaluation framework to quantify cross-modal ...
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Modeling the chemical and photophysical properties of gold complexes.

Modeling the chemical and photophysical properties of gold complexes.

Date: August 2004
Creator: Barakat, Khaldoon A.
Description: Various gold complexes were computationally investigated, to probe their photophysical, geometric, and bonding properties. The geometry of AuI complexes (ground state singlet) is very sensitive to the electronic nature of the ligands: σ-donors gave a two-coordinate, linear shape; however, σ-acceptors yielded a three-coordinate, trigonal planar geometry. Doublet AuIIL3 complexes distort to T-shape, and are thus ground state models of the corresponding triplet AuIL3. The disproportionation of AuIIL3 to AuIL3 and AuIIIL3 is endothermic for all ligands investigated, however, σ-donors are better experimental targets for AuII complexes. For dimeric AuI complexes, only one gold center in the optimized triplet exciton displays a Jahn-Teller distortion, and the Au---Au distance is reduced versus the ground state distance (i.e., two reasons for large Stokes' shifts).
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Modeling the Impact and Intervention of a Sexually Transmitted Disease: Human Papilloma Virus

Modeling the Impact and Intervention of a Sexually Transmitted Disease: Human Papilloma Virus

Date: May 2006
Creator: Corley, Courtney D.
Description: Many human papilloma virus (HPV) types are sexually transmitted and HPV DNA types 16, 18, 31, and 45 account for more than 75% if all cervical dysplasia. Candidate vaccines are successfully completing US Federal Drug Agency (FDA) phase III testing and several drug companies are in licensing arbitration. Once this vaccine become available it is unlikely that 100% vaccination coverage will be probable; hence, the need for vaccination strategies that will have the greatest reduction on the endemic prevalence of HPV. This thesis introduces two discrete-time models for evaluating the effect of demographic-biased vaccination strategies: one model incorporates temporal demographics (i.e., age) in population compartments; the other non-temporal demographics (i.e., race, ethnicity). Also presented is an intuitive Web-based interface that was developed to allow the user to evaluate the effects on prevalence of a demographic-biased intervention by tailoring the model parameters to specific demographics and geographical region.
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Modeling the Relationship Between Golden Algae Blooms in Lake Texoma, Usa, Versus Nearby Land Use and Other Physical Variables

Modeling the Relationship Between Golden Algae Blooms in Lake Texoma, Usa, Versus Nearby Land Use and Other Physical Variables

Date: August 2012
Creator: Ware, Trudy M.
Description: Pyrmnesium parvum, commonly known as golden algae, is an algal species that under certain circumstances releases toxins which can lead to fish kills and the death of other economically and ecologically important organisms. One of the major objectives of the study was to investigate whether a relationship exists between land use and Prymnesium parvum abundance in littoral sites of Lake Texoma, USA. Another objective was to investigate whether a relationship exists between other physical variables and counts of P. parvum. Lastly, developing a valid model that predicts P. parvum abundance was an objective of the study. Through stepwise regression, a small but highly significant amount of the variation in P. parvum counts was found to be explained by wetlands, soil erodibility and lake elevation. The developed model provides insight for potential golden algae management plans, such as maintaining wetlands and teaching land owners the relationship between soil erosivity and golden algae blooms.
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Modeling the role of blogging in librarianship

Modeling the role of blogging in librarianship

Date: August 2007
Creator: Stephens, Michael
Description: This phenomenological study examines the motivations and experiences of librarians who author professionally-focused Weblogs. I constructed a model of librarianship based on Wilson and Buckland. The results show a close fit between librarian bloggers and the ideals of the field as expressed by two primary library and information science philosophers. A Web survey generated 239 responses to demographic and open-ended questions. Using the results of the survey, I analyzed demographic data and performed a phenomenological analysis of the open-ended questions. A list of category responses was generated from each set of answers via the coding of descriptive words and phrases. Results indicated the motivations of librarian bloggers are based around themes of sharing, participation in community, and enhanced professional development. Respondents reported feeling more connected to the profession and to colleagues across the world because of blogging. Respondents perceived the librarian blogosphere as a community with both positive aspects - feedback, discussion, and support - and negative aspects - insular voices, divides between technologists and librarians, and generational rifts. Respondents also reported an increased ability to keep current, improved writing skills, and opportunities to speak and contribute to professional journals.
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Modeling Transition Metal Catalysts for Small Molecule Activation and Functionalization

Modeling Transition Metal Catalysts for Small Molecule Activation and Functionalization

Date: May 2013
Creator: Figg, Travis M.
Description: There is a high demand for the development of processes for the conversion of ubiquitous molecules into industrially useful commodities. Transition metal catalysts are often utilized for the activation and functionalization of small organic molecules due to their diverse nature and proven utility with a myriad of chemical transformations. The functionalization of methane (CH4) and dinitrogen (N2) to methanol (CH3OH) and ammonia (NH3) respectively is of particular interest; however, both methane and dinitrogen are essentially inert due to the inherit strength of their bonds. In this dissertation a series of computational studies is performed to better understand the fundamental chemistry behind the functionalization of methane and the activation of dinitrogen in a homogeneous environment. A catalytic cycle is proposed for the oxy-functionalization of methane to methanol. The cycle consists of two key steps: (1) C-H activation across a metal-alkoxide bond (M-OR), and (2) regeneration of the M-OR species through an oxy-insertion step utilizing external oxidants. The C-H activation step has been extensively studied; however, the latter step is not as well understood with limited examples. For this work, we focus on the oxy-insertion step starting with a class of compounds known to do C-H activation (i.e., Pt(II) systems). Computational studies ...
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