Master of Arts, Miami University, 2024, Economics

This study attempts to estimate direct network effects within the online video game platform Steam. To overcome Manski's ``reflection problem" in identifying this effect, I use three holidays - the Chinese National Day in 2023, the American Thanksgiving in 2023, and the American Martin Luther King Holiday in 2024 - as exogenous regional shocks and employ the differences-in-differences method on time and players' location. Using data from Steam API, I estimate a model of daily playtime and the choice of whether to play at all, allowing utility to vary with players' own location, day of the week, and their friends' locations. This model permits the localized nature of network effects observed in the data. However, because of the limited number of observed US-to-non-US and Chinese-to-non-Chinese friendships on the platform, the data is underpowered to detect an effect.

Committee: Charles Moul (Advisor); Josh Ederington (Committee Member); Peter Nencka (Committee Member) Subjects: Economics

Doctor of Education (EdD), Ohio University, 2017, Educational Administration (Education)

This study was a quest toward understanding how superintendents prepare districts for change in response to various internal and external environmental forces. This study focused on aspects of the change readiness process. Finally, this study sought to answer questions regarding aspects of a climate and specific strategies superintendents utilize that hinder or assist in preparing a district for change. This research was a qualitative case study bounded by a shared experience. The informants consisted of a purposeful selection of maximum variation, four public school superintendents from Ohio. The four informants were identified and data were collected using the interview process. Saldana's (2010) multi-cycle coding method was used to analyze the data. Interpretation of the data revealed support for the three conditions of a climate included in Schein's (2010) Change Model. Analysis of the interview data also revealed a number of strategies that assisted superintendents in preparing a district for change (persuasive communication, active participation, pacing, and discrepancy.) Lastly, various strategies were identified as hindering the process of preparing a district for change (personal support and discrepancy).

Committee: Krisanna Machtmes Ph.D. (Committee Chair); Dwan Robinson Ph.D. (Committee Member); Charles Lowery Ed.D. (Committee Member); Eugene Geist Ph.D. (Committee Member) Subjects: Education; Education Policy; Educational Leadership; Educational Psychology; Organization Theory; Organizational Behavior

Master of Science, Miami University, 2015, Physics

This thesis presents the application of an empirical model of total internal reflection (TIR) we recently developed in conjunction with a home-built sensor to detect nanoaggregates in highly scattering opaque polystyrene colloidal suspensions. The nanoaggregates are detected directly without any sample dilution or special sample preparation. Additional results on nanoaggregate detection in gold nanoparticle suspensions are presented. Preliminary tests of our model and sensor in an absorbing dye solution are also presented.

Committee: Samir Bali PhD (Advisor); Lalit Bali PhD (Advisor); Jason Berberich PhD (Advisor); Jon Scaffidi PhD (Advisor); James Clemens PhD (Committee Member); Karthik Vishwanath PhD (Committee Member) Subjects: Analytical Chemistry; Biochemistry; Biomedical Engineering; Biomedical Research; Biophysics; Chemical Engineering; Chemistry; Experiments; Materials Science; Medical Imaging; Molecular Physics; Molecules; Nanoscience; Nanotechnology; Optics; Organic Chemistry; Physics; Polymer Chemistry; Polymers; Scientific Imaging

Master of Arts (M.A.), University of Dayton, 2015, Psychology, Clinical

The present study examined student outcomes across a semester of service-learning participation. The study examined two hypotheses: (1) students engaged in service-learning will have significant changes in community service self-efficacy (an in the related civic action construct) and in endorsement of myths and social stigma towards homelessness; and (2) the pre-to-post semester improvements will be greater for students engaged in structured DEAL Model reflection compared to students engaged in the less structured routine reflection. Undergraduate students (N= 30) were randomly assigned to either the DEAL Model reflection or routine reflection condition. Over the course of the semester, students were required to complete four reflections exercises, which differed in structure based on condition. While there were a number of nonsignificant findings, there was partial support for the hypotheses. Specifically, students' endorsement of myths and social stigma significantly decreased from pre-to-post assessment. Further results indicated that the DEAL Model reflection group had a significant decrease in endorsement of myths and social stigma, while the routine reflection did not have this significant decrease. Additionally, the DEAL Model reflection group had a significant increase in civic action from pre-to-post semester assessment. High pre-semester scores on community service self-efficacy measures may have created a ceiling effect that precluded an adequate assessment of pre- to post-semester changes in that construct. However, a retrospective measure of this same construct indicated that students strongly endorsed the notion that participation in the service-learning project substantially contributed to their perceptions of strong community service self-efficacy. The results are interpreted within the context of past theory and research. Recommendations for future research are provided, including future examination of qualitative data (i.e., written ref (open full item for complete abstract)

Committee: Roger Reeb Dr. (Advisor); Ronald Katsuyama Dr. (Committee Member); Theophile Majka Dr. (Committee Member) Subjects: Higher Education; Psychology

Doctor of Philosophy, University of Toledo, 2014, Curriculum and Instruction

Young adult illiteracy is an epidemic in our country, and the traditional model of literacy education will not serve the needs of struggling readers. The purpose of this study was to discover if utilizing my pedagogical provided an impactful experience on our teacher candidates. Can a literacy program provide a transactional learning experience and what is that experience? My study is a qualitative, exploratory study that looks at the experiences of teacher candidates and how they experienced the process of this literacy model. The participants had the opportunity to directly apply the instructional, literacy strategies learned and discussed in class to working with a young adult struggling reader. Through collaboration and dialogue, teacher candidates created connections and literacy materials that applied directly to their students' lives, creating and experiencing an authentic, transactional literacy experience. Candidates documented their tutoring event through case studies, emails, reflections, and interviews and then discussed with me their understanding of the process and what they took away from the experience. This helped me evaluate if the pedagogical model implemented in the teacher preparation class was a success.

Committee: Leigh Chiarelott (Committee Co-Chair); Jenny Denyer (Committee Co-Chair); Mark Templin (Committee Member); Dale Snauwaert (Committee Member) Subjects: Education; Literacy; Reading Instruction; Secondary Education; Teacher Education

Doctor of Philosophy (PhD), Ohio University, 1981, Electrical Engineering & Computer Science (Engineering and Technology)

UTD terrain reflection model with application to ILS glide slope

Committee: Ray Luebbers (Advisor) Subjects:

PHD, Kent State University, 2007, College of Arts and Sciences / Chemical Physics

We investigate the optical properties of liquid crystal devices whose dark states are optically compensated to give minimum transmittance. Firstly, the effect of multiple internal reflections on the extinction ratio of perfectly compensated liquid crystal devices is studied. We find the previously unexplained wavelength dependence of light leakage in an ideally compensated device is caused by the interference of the internally reflected ordinary and extraordinary waves. While these effects have not been previously made clear, they can place a limit on the performance of liquid crystal devices used as displays, optical switches and optical attenuators. Secondly, we study the off-axis light transmission characteristics of the bright state of common liquid crystal device modes. Our research shows there is an unexpected universal shape of the off-axis light transmittance in its bright state, regardless of what liquid crystal mode is used. To understand this surprising fact, we consider simple dark and bright state models in terms of phase retardation and transmittance. We also investigate the luminance and color properties of bright state common LCDs such as ECB, VA, Pi-cell, and TN modes. According to the results, the universality of the optical properties of a bright state is maintained not only in the transmittance but also in the luminance and color properties. Thirdly, we have studied the off-axis light transmission properties of the bright state in Pi-cell devices as a function of the white state director configuration. Above a critical pretilt angle or white state voltage, the light transmittance is a much stronger function of the incident angle of light. To understand the facts, we develop a model that explains this result and provides a description of the basic issues affecting the optics of these types of devices. Finally, we explore the phase compensation of the dark states in LCDs, and find that there is a limitation for the compensation of a uniaxial layer (open full item for complete abstract)

Committee: Philip Bos (Advisor) Subjects: Physics, Optics

Doctor of Philosophy, The Ohio State University, 2013, Electrical and Computer Engineering

In an image, color feature is highly discriminative for identifying the scene objects, but it is often difficult to uniquely extract. The challenge is primarily related to variations in the object's color in different images captured under varying illuminations at different viewpoints. A number of methods have been developed to find true object color, which is independent of illuminations and viewpoints. In this dissertation, we will address the problems of color variations in images and introduce a novel approach for simultaneously estimating the diffuse and specular reflections from a collection of images based on the dichromatic reflection model. By minimizing a cost function, the observed color in a scene can be decomposed into diffuse reflection (modeling the object color), specular reflection (modeling the illumination) and geometry parameters of the dichromatic reflection model. We refer to the resulting color of diffuse reflection as true object color. The estimated parameters of each pixel in the set of images are sequentially obtained by Gauss Seidel iterative approach [60]. The robustness of our method is demonstrated using a set of home-generated and standard image sets. We also demonstrate that our proposed method can be used to estimate the dichromatic reflection model of an object from a single image. The estimated true object color allows for excellent segmentation performance.

Committee: Hooshang Hemami PhD (Advisor); Alper Yilmaz PhD (Committee Member); Bradley Clymer PhD (Committee Member) Subjects: Computer Engineering; Electrical Engineering