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 Collection: UNT Theses and Dissertations
Design and Application of Phased Array System

Design and Application of Phased Array System

Date: August 2013
Creator: Ren, Han
Description: Since its invention, phased array has been extensively applied in both military and civil areas. The applications include target detecting and tracking, space probe communication, broadcasting, human-machine interfaces, and remote sensing. Although the phased array applications show a broad range of potential market, there are some limitations of phased array's development: high cost, complex structure, narrow bandwidth, and high power consumption. Therefore, novel ideas are needed to reduce these constraints. In this thesis, several new approaches about the design and application of phased array are presents. First, the principle of phased array and fundamental design equations are introduced. Second, a new application of phased array antenna for radar respiration measurement is presented. By integrating a 4×4 Butler matrix with four-element antenna array, there will be four distinct main beams in radiation pattern. This new approach can improve the measurement accuracy and realize a high detecting rate. Third, a compact phased array antenna system based on dual-band operations is introduced. Dual-band function can make N-antenna system obtain 2N unique radiation beams (N is an integer) and achieve a significant size reduction compared to the conventional single-band system. To verify the design concept, a four-element phased array antenna working at 5GHz and ...
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An Investigation of the Phase Model of Psychotherapy Across Therapeutic Orientations: Are Different Approaches Actually All That Different?

An Investigation of the Phase Model of Psychotherapy Across Therapeutic Orientations: Are Different Approaches Actually All That Different?

Date: August 2013
Creator: Herbert, Gregory L.
Description: The current study investigated the process of change underlying two different evidence-based treatments that yield similar outcome effectiveness in the treatment of depression: Cognitive Therapy (CT) and Interpersonal Therapy (IPT). The phase model of psychotherapeutic change (Howard et al., 1993) change is used to provide both a theoretical and practical framework in which to assess different patterns of change across the treatment modalities. The phase model posits that recovery from distress occurs in three sequential stages: remoralization, remediation and rehabilitation. CT can be conceptualized as a treatment in which the primary focus is on the treatment of symptoms (remediation), whereas IPT can typically be conceptualized as focusing on interpersonal conflicts and functioning (rehabilitation). The study utilized the TDCRP dataset (Elkin et al., 1985). Survival analysis indicated no significant difference in terms of onset or pattern of improvement across treatment orientations. Chi square analyses indicated individuals treated with IPT spend significantly more time engaged in rehabilitation compared to their CT counterparts. Taken together, these findings represent evidence that the process of therapeutic change is similar, if not virtually identical, across therapeutic orientation. The analyses also indicate that the phases of therapy may not necessarily be mutually exclusive and sequential, but may ...
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Development of Novel Semi-conducting Ortho-carborane Based Polymer Films: Enhanced Electronic and Chemical Properties

Development of Novel Semi-conducting Ortho-carborane Based Polymer Films: Enhanced Electronic and Chemical Properties

Date: August 2013
Creator: Pasquale, Frank L.
Description: A novel class of semi-conducting ortho-carborane (B10C2H12) based polymer films with enhanced electronic and chemical properties has been developed. The novel films are formed from electron-beam cross-linking of condensed B10C2H12 and B10C2H12 co-condensed with aromatic linking units (Y) (Y=1,4-diaminobenzene (DAB), benzene (BNZ) and pyridine (PY)) at 110 K. The bonding and electronic properties of the novel films were investigated using X-ray photoelectron spectroscopy (XPS), UV photoelectron spectroscopy (UPS) and Mulliken charge analysis using density functional theory (DFT). These films exhibit site-specific cross-linking with bonding, in the pure B10C2HX films, occurring at B sites non-adjacent to C in the B10C2H12 icosahedra. The B10C2H12:Y films exhibit the same phenomena, with cross-linking that creates bonds primarily between B sites non-adjacent to C in the B10C2H12 icosahedra to C sites in the Y linking units. These novel B10C2HX: Y linked films exhibit significantly different electron structure when compared to pure B10C2HX films as seen in the UPS spectra. The valence band maxima (VBM) shift from - 4.3 eV below the Fermi level for pure B10C2HX to -2.6, -2.2, and -1.7 for B10C2HX:BNZ, B10C2HX:PY, and B10C2HX:DAB, respectively. The top of the valence band is composed of states derived primarily from the Y linking units, suggesting ...
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Central Office Administrators' Perceptions of the Professional Learning Community Process

Central Office Administrators' Perceptions of the Professional Learning Community Process

Date: August 2013
Creator: Pruitt, Mary E.
Description: This study provides a qualitative interpretation of the work done by central office administrators in a school district in Texas as they supported and built capacity for the professional learning community (PLC) process over a five year time period. Literature by PLC scholars, especially R. DuFour, R.B. DuFour, Eaker, Hord, Hipp, Huffman, and Olivier, informed development of the study. In a school district of 19,000 students and 2,000 staff members, ten central office administrators were interviewed to gain their perceptions of their roles in the PLC process. Interviews were analyzed through the processes of initial, focused, and theoretical coding. Documents were examined and used as supplemental sources of data to corroborate the perspectives provided. Findings revealed the story of central office administrators who worked interdependently to support and build capacity in the implementation and sustainment of the PLC process. A thick description of the work based on their perceptions offers actions and behaviors of administrators specific to their roles and practices and protocols developed to hold the work together. A grounded theory was developed with regard to central office administrators' support and capacity-building for the PLC process. From the administrators' perceptions, six theoretical categories relating to central office support and ...
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A Relationship-based Cross National Customer Decision-making Model in the Service Industry

A Relationship-based Cross National Customer Decision-making Model in the Service Industry

Date: August 2013
Creator: Boakye, Kwabena G.
Description: In 2012, the CIA World Fact Book showed that the service sector contributed about 76.6% and 51.4% of the 2010 gross national product of both the United States and Ghana, respectively. Research in the services area shows that a firm's success in today's competitive business environment is dependent upon its ability to deliver superior service quality. However, these studies have yet to address factors that influence customers to remain committed to a mass service in economically diverse countries. In addition, there is little research on established service quality measures pertaining to the mass service domain. This dissertation applies Rusbult's investment model of relationship commitment and examines its psychological impact on the commitment level of a customer towards a service in two economically diverse countries. In addition, service quality is conceptualized as a hierarchical construct in the mass service (banking) and specific dimensions are developed on which customers assess their quality evaluations. Using, PLS path modeling, a structural equation modeling approach to data analysis, service quality as a hierarchical third-order construct was found to have three primary dimensions and six sub-dimensions. The results also established that a country's national economy has a moderating effect on the relationship between service quality and ...
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The Effects of the Texas Reading First Response to Intervention Program on Student Achievement and Campus Special Education Rates

The Effects of the Texas Reading First Response to Intervention Program on Student Achievement and Campus Special Education Rates

Date: August 2013
Creator: Batts, Troy D.
Description: The purpose of this study was to examine special education populations, special education reading achievement, and regular education reading achievement in relation to the implementation of the Reading First three-tiered model as a response to Intervention platform. The population for this study focused on rural schools with Grades K-3 in attendance. Schools participated in the reading first grant period of the 2003-2009 school years. Forty-seven Texas Reading First schools were compared to 47 campuses having similar populations, socioeconomic makeups, and grade structures. This study utilized quantitative research measures to evaluate the level of special education populations on Reading First campuses using a response to intervention model. Quantitative measures were also used to evaluate those same campuses achievement rates of both special education and regular education students on the Texas Assessment of Knowledge and Skills reading tests. The study's outcome data showed little to no statistic significance for the three research questions. However, the inferential statistics showed a decrease in the special education population of the Reading First schools. Inferential statistics also indicated both the special education and the regular education students showed growth on the Texas Assessment of Knowledge and Skills reading tests. The use of a response to intervention ...
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Endocrine Disruption of Levonorgestrel in Early-life Stages of Fathead Minnows, Pimephales Promelas

Endocrine Disruption of Levonorgestrel in Early-life Stages of Fathead Minnows, Pimephales Promelas

Date: August 2013
Creator: Overturf, Matthew D.
Description: Pharmaceuticals have routinely been detected in the environment resulting in a growing concern about whether these drugs could elicit effects on aquatic organisms. The concerns are centered on the highly conserved nature of mammalian therapeutic targets in fish. These pharmaceuticals are found at very low levels in the environment, which can result in sub-lethal effects in aquatic organisms. Therefore, 28 d early-life stage studies were conducted on six pharmaceuticals to assess their impacts on survival and growth fathead minnow larvae. Two pharmaceuticals tested, carbamazepine and fenofibrate, resulted in no alterations to survival and growth. However, amiodarone, clozapine, dexamethasone, and levonorgestrel (LNG) reduced survival at concentrations tested with LNG being the most potent at 462 ng/L. Survival was increased with amiodarone and clozapine; however LNG significantly decreased growth at 86 ng/L. Therefore, the most potent pharmaceutical tested was the synthetic progestin LNG with survival and growth impacts at concentrations less than 1 μg/L. Further analysis was conducted by measuring specific endocrine related mRNA transcript profiles in FHM larvae following the 28 d ELS exposure to LNG. Transcripts of 3β-HSD, 20β-HSD, and FSH were significantly down-regulated following 28 d exposure to both 16.3 and 86.9 ng/L LNG. Also, CYP19a expression was significantly ...
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Student Experiences and Expectations Related to the Vertical Transfer Process From Two Feeder Community Colleges of a Senior Institution

Student Experiences and Expectations Related to the Vertical Transfer Process From Two Feeder Community Colleges of a Senior Institution

Date: August 2013
Creator: Miller, Brandon B. A.
Description: The purpose of this study was to understand the experiences and expectations of community college students attending Temple College and Central Texas College regarding what they may expect as part of the vertical transfer process in order to improve the likelihood of their persistence to graduation at Texas A&M University-Central Texas (TAMUCT). The target population was approximately 700 students enrolled in two feeder Texas community colleges who had expressed intent to transfer to TAMUCT. The response rate was 19%, and 136 useable surveys were used for analysis. The sample was 74% female, 45% White with the majority minority. To assess the relationships between community college experiences and transfer expectation variables, correlations and logistic regression were used. No linear relationships were found regarding gender, age, ethnicity, highest level of parents' education, the aspirational variables of highest academic degree intend to obtain at any college or university and at TAMUCT, and the feeder community college attended and the two scales. A statistically significant relationship was found between parental income level and reported community college experiences (F(4, 79) = 2.612, p = .042) and vertical transfer expectations (F(4, 52) = 3.318, p = .017). Community college students from lower socioeconomic backgrounds may utilize ...
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Glucose As an Energy Source to Increase Self-control in Restrained Eaters

Glucose As an Energy Source to Increase Self-control in Restrained Eaters

Date: August 2013
Creator: Valentine, Lisa. M.
Description: Research evidence is suggestive of a strength model of self-control, also known as ego depletion, in social psychological literature. Engaging in an initial task of self-control depletes a limited resource, resulting in less self-control on a subsequent, unrelated task. The strength model of self-control has been applied to many practical, everyday situations, such as eating behaviors among dieters. Newer studies suggest that blood glucose is the resource consumed during acts of self-control. Consuming glucose seems to "replete" individuals who have been depleted, improving performance and self-control. The current study aimed to examine the effects of ego-depletion on restrained eaters. The hypothesis was that restrained eaters who were depleted by a task of self-control would exhibit more disinhibition on a taste-test task than would restrained eaters who were not depleted. However, if the participants were given glucose following the depletion task, then their self-control would be "repleted" and they would exhibit similar control to that of the non-depleted participants. Contrary to expectations there were no differences between the groups in terms of total amount of cookies consumed. These results are inconsistent with a glucose model of self-control. Suggestions for future research and implications of the findings are discussed.
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Values and Valuing in a College Population

Values and Valuing in a College Population

Date: August 2013
Creator: Hernandez, Nikki C.
Description: Values and valuing behavior have many conceptualizations. Despite how they are defined, values have a significant impact on behavior and are idiosyncratic in nature. The present study reviewed values research and sought to explore values identification and successful valued living among an archived sample of university students. Specifically, in a convenience sample of 282 undergraduate students, variables that affect values identification and behavior such as ethnicity, gender, psychological distress, and psychological flexibility were identified. Results indicated that university students identified with more than one valued living domain (as measured by the PVQ) and that contextual factors such as ethnicity, gender, age, and religiosity/spirituality were associated with specific values endorsed. Furthermore, psychological distress, including depression and anxiety (as measured by the DASS) was negatively correlated with values purity – the extent to which values are freely chosen. Finally, psychological flexibility (low experiential avoidance as measured by the AAQ-2), predicted values purity and successful living in accordance with identified values, and the relationship between these two variables was mediated by psychological flexibility.
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