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  Partner: UNT Libraries
 Decade: 2010-2019
 Year: 2012
1/F Baseband Noise Suppression in Ofdm Using Kalman Filter

1/F Baseband Noise Suppression in Ofdm Using Kalman Filter

Date: May 2012
Creator: Rodda, Lasya
Description: As the technology is advances the reduced size of hardware gives rise to an additive 1/f baseband noise. This additive 1/f noise is a system noise generated due to miniaturization of hardware and affects the lower frequencies. Though 1/f noise does not show much effect in wide band channels because of its nature to affect only certain frequencies, 1/f noise becomes a prominent in OFDM communication systems where narrow band channels are used. in this thesis, I study the effects of 1/f noise on the OFDM systems and implement algorithms for estimation and suppression of the noise using Kalman filter. Suppression of the noise is achieved by subtracting the estimated noise from the received noise. I show that the performance of the system is considerably improved by applying the 1/f noise suppression.
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9-Lipoxygenase Oxylipin Pathway in Plant Response to Biotic Stress

9-Lipoxygenase Oxylipin Pathway in Plant Response to Biotic Stress

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Date: May 2012
Creator: Nalam, Vamsi J.
Description: The activity of plant 9-lipoxygenases (LOXs) influences the outcome of Arabidopsis thaliana interaction with pathogen and insects. Evidence provided here indicates that in Arabidopsis, 9-LOXs facilitate infestation by Myzus persicae, commonly known as the green peach aphid (GPA), a sap-sucking insect, and infection by the fungal pathogen Fusarium graminearum. in comparison to the wild-type plant, lox5 mutants, which are deficient in a 9-lipoxygenase, GPA population was smaller and the insect spent less time feeding from sieve elements and xylem, thus resulting in reduced water content and fecundity of GPA. LOX5 expression is induced rapidly in roots of GPA-infested plants. This increase in LOX5 expression is paralleled by an increase in LOX5-synthesized oxylipins in the root and petiole exudates of GPA-infested plants. Micrografting experiments demonstrated that GPA population size was smaller on plants in which the roots were of the lox5 mutant genotype. Exogenous treatment of lox5 mutant roots with 9-hydroxyoctadecanoic acid restored water content and population size of GPA on lox5 mutants. Together, these results suggest that LOX5 genotype in roots is critical for facilitating insect infestation of Arabidopsis. in Arabidopsis, 9-LOX function is also required for facilitating infection by F. graminearum, which is a leading cause of Fusarium head ...
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2012 Presidential Primaries

2012 Presidential Primaries

Date: April 2012
Creator: Mondragon-Becker, Antonio
Description: This poster introduces the faculty lecture series UNT Speaks Out on the 2012 Presidential Primaries. This series features Dr. Tony Carey, assistant professor in the Department of Political Science, Dr. Matthew Eshbaugh-Soha, associate professor in the Department of Political Science, and Dr. Brian Lain, associate professor in the Department of Communications Studies and director of UNT's Debate Program.
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3D Reconstruction Using Lidar and Visual Images

3D Reconstruction Using Lidar and Visual Images

Date: December 2012
Creator: Duraisamy, Prakash
Description: In this research, multi-perspective image registration using LiDAR and visual images was considered. 2D-3D image registration is a difficult task because it requires the extraction of different semantic features from each modality. This problem is solved in three parts. The first step involves detection and extraction of common features from each of the data sets. The second step consists of associating the common features between two different modalities. Traditional methods use lines or orthogonal corners as common features. The third step consists of building the projection matrix. Many existing methods use global positing system (GPS) or inertial navigation system (INS) for an initial estimate of the camera pose. However, the approach discussed herein does not use GPS, INS, or any such devices for initial estimate; hence the model can be used in places like the lunar surface or Mars where GPS or INS are not available. A variation of the method is also described, which does not require strong features from both images but rather uses intensity gradients in the image. This can be useful when one image does not have strong features (such as lines) or there are too many extraneous features.
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Absorptive Capacity:  An Empirical Examination of the Phenomenon and Relationships with Firm Capabilities

Absorptive Capacity: An Empirical Examination of the Phenomenon and Relationships with Firm Capabilities

Date: May 2012
Creator: Daspit, Josh
Description: The field of strategic management addresses challenges that firms encounter in an attempt to remain competitive. The ability to explain variation in firm success through examination of knowledge flows has become a prominent focus of research in the strategic management literature. Specifically, researchers have sought to further examine how firms convert knowledge, a phenomenon conceptualized as absorptive capacity. Absorptive capacity is the firm’s ability to acquire, assimilate, transform, and exploit knowledge. Few studies have captured the richness and multi-dimensionality of absorptive capacity, and it remains to be understood how the dimensions of the phenomenon convert knowledge. Furthermore, how absorptive capacity influences the firm remains to be understood. To address these research gaps, this dissertation seeks to (1) determine how absorptive capacity converts knowledge, and (2) determine how absorptive capacity influences firm capabilities. The research questions are investigated using structural modeling techniques to analyze data collected from software-industry firms. The findings offer contributions to the absorptive capacity and capability literatures. For example, absorptive capacity is hypothesized to consist of complex relationships among its internal dimensions. However, findings of this study suggest the relationships among the dimensions are linear in nature. This finding is in line with the theoretical foundations of and ...
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Acculturation and Depression in Older Mexican American Adults: the Role of Social Support

Acculturation and Depression in Older Mexican American Adults: the Role of Social Support

Date: August 2012
Creator: Caballero, Daniela
Description: Despite socioeconomic disadvantages, less acculturated Mexican Americans tend to exhibit better mental health than their more acculturated counterparts. However, in the case of older Mexican American adults, research has demonstrated the opposite to be true (Gonzalez, Haan, & Hinton, 2001). A variable of interest potentially responsible for this difference is social support. Thus, the current study proposed to investigate the mediation and moderation effects that social support has on the relationship between acculturation and depression in older Mexican American adults age 60 or older. Data from the Health and Retirement Study (HRS) was analyzed. Results showed that the mediating effect of contact with one’s children (-.109*) and the moderating effect of total social support and contact with one’s children (-.127*; -.103*) were statistically significant in the relationship between acculturation and depression. Although these effects are small they may still hold important implications for better understanding this population.
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Adoptive Parenthood: an Exploratory Study of the Influence of Pre-adoption Communication Satisfaction on Post-adoption Family Adjustment and Coping

Adoptive Parenthood: an Exploratory Study of the Influence of Pre-adoption Communication Satisfaction on Post-adoption Family Adjustment and Coping

Date: May 2012
Creator: Seebeck, Lara N.
Description: There are over a million adopted children in the United States, which makes up over 2% of the population. in spite of the fact that the majority of children are adopted into loving and caring homes, early life trauma puts them at higher risk for developing behavioral and emotional problems than non-adopted children. Due to these issues, many adoptive parents encounter post-adoption stress. This stress is often linked to minimal education regarding short- and long-term challenges associated with adoption. the adoption agency is likely the best group for addressing challenges, yet few researchers have studied adoption agency communication and adoptive parent adjustment. in this study I examined pre-adoption communication satisfaction, post-adoption adjustment (life change and parental adjustment), and coping strategies. Hypothesis 1 questioned the relationship between adoptive parents’ pre-adoption communication satisfaction with their social workers and post-adoption family adjustment; this hypothesis was supported only for problems related to home and work life adjustment. Hypothesis 2 predicted coping strategies would mediate the relationship between communication satisfaction and family adjustment. H2 was not supported for both life change and parental adjustment. Research Questions 1a and 1b inquired about the coping strategy that had an impact on life change and parental adjustment; escape-avoidance ...
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The Affect of Mobile Performance Support Devices on Anxiety and Self-Efficacy of Hospital Float Staff

The Affect of Mobile Performance Support Devices on Anxiety and Self-Efficacy of Hospital Float Staff

Date: May 2012
Creator: McKee, Megan Riley
Description: Floating describes the act of staff moving from one unit to another based on the needs of the patients in a hospital. Many staff who float to different units express negative feelings, including anxiety and lack in self-efficacy. However, floating is both an economical and efficient method to use staff across the hospital, especially with current staffing shortages in the United States. This study investigated how the use of mobile performance support devices may help reduce anxiety and increase self-efficacy for those staff who float to different units. with access to multiple resources available on the mobile device, Bandura's social learning theory and self-efficacy concept set the framework through modeling, observing, and imitating others in order to reproduce certain behaviors and tasks and believe in one's capability to perform. a quantitative study incorporating the retrospective pretest-posttest design was conducted using the population of float staff, including both nurses and respiratory therapists, from Children's Medical Center of Dallas. Both the State-Trait Anxiety Inventory and General Self-Efficacy Scale, along with a basic demographic tool, were used to explore anxiety and self-efficacy in relation to the usage of mobile performance support devices. Findings can be used to impact the negative feelings of staff ...
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Affective Forecasting: the Effects of Immune Neglect and Surrogation

Affective Forecasting: the Effects of Immune Neglect and Surrogation

Date: August 2012
Creator: Burkman, Summer Dae
Description: Studies of affective forecasting examine people’s ability to predict (forecast) their emotional (affective) responses to future events. Affective forecasts underlie nearly all decisions people make and the actions they take. However, people engage in systematic cognitive errors when making affective forecasts and most often overestimate the intensity and duration of their emotional responses. Understanding the mechanisms that lead to affective forecasting errors (e.g., immune neglect) and examining the utility of methods for improving affective forecasting errors (e.g., surrogation) can provide highly valuable information for clinicians as they assist clients in determining their goals both for therapy and for life. The first purpose of the current study was to determine if affective forecasting errors due to immune neglect lead to misjudgments about the relative emotional impact of minor versus moderate negative experiences (i.e., trauma severity). The second purpose was to examine the utility of surrogation for improving affective forecasts. Potential interaction effects between these two variables were also examined. The current study utilized a 2 (Trauma Severity: minor, moderate) X 3 (Prediction Information: surrogation information only, simulation information only, both types of information) experimental design. Undergraduates were recruited via the SONA system and randomly assigned to one of the six experimental ...
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After the Planes

After the Planes

Date: May 2012
Creator: Boswell, Timothy
Description: The dissertation consists of a critical preface and a novel. The preface analyzes what it terms “polyvocal” novels, or novels employing multiple points of view, as well as “layered storytelling,” or layers of textuality within novels, such as stories within stories. Specifically, the first part of the preface discusses polyvocality in twenty-first century American novels, while the second part explores layered storytelling in novels responding to World War II or the terrorist attacks of 9/11. The preface analyzes the advantages and difficulties connected to these techniques, as well as their aptitude for reflecting the fractured, disconnected, and subjective nature of the narratives we construct to interpret traumatic experiences. It also acknowledges the necessity—despite its inherent limitations—of using language to engage with this fragmentation and cope with its challenges. The preface uses numerous novels as examples and case studies, and it also explores these concepts and techniques in relation to the process of writing the novel After the Planes. After the Planes depicts multiple generations of a family who utilize storytelling as a means to work through grief, hurt, misunderstanding, and loss—whether from interpersonal conflicts or from war. Against her father’s wishes, a young woman moves in with her nearly-unknown grandfather, ...
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