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  Partner: UNT Libraries
 Decade: 2010-2019
 Year: 2012
 Collection: UNT Theses and Dissertations
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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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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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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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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“Almost Astronauts”: Short Stories

“Almost Astronauts”: Short Stories

Date: May 2012
Creator: Miller, Laura I.
Description: In this collection of short stories, I abduct experiences from my own life and take them on an imaginative journey. I experiment with elements of structure and point of view, often incorporating the magical or surreal to amplify the narrator’s internal landscape. As demonstrated in the title story, “Almost Astronauts,” these stories all deal with a sudden and sometimes destructive shift in the narrator’s perspective.
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Alterations in Fatty Acid Amide Hydrolase (Faah) Transcript Levels and Activity Lead to Changes in the Abiotic Stress Susceptibility of Arabidopsis Thaliana

Alterations in Fatty Acid Amide Hydrolase (Faah) Transcript Levels and Activity Lead to Changes in the Abiotic Stress Susceptibility of Arabidopsis Thaliana

Date: May 2012
Creator: Gonzalez, Gabriel
Description: N-Acylethanolamines (NAEs) are a class of bioactive lipids, and FAAH is one of the enzymes responsible for degrading NAEs in both plants and animals. in plants, FAAH appears to be closely associated with ABA, a phytohormone which has long been associated with plant stress responses, since the overexpression of FAAH in Arabidopsis results in ABA hypersensitivity. Therefore, it is reasonable to speculate that alterations in FAAH transcript levels will result in altered stress responses in plants. to investigate this hypothesis experiments were carried out in which wild type (WT), FAAH-overexpressing (OE), and T-DNA insertional FAAH knockouts of Arabidopsis (faah) were grown in MS media under stress conditions. the stress conditions tested included chilling stress, heavy metal stress induced by cadmium or copper, nutrient limitations induced by low phosphorus or low nitrogen, salt stress induced with NaCl, and osmotic stress induced with mannitol. the OE plants were consistently hypersensitive to all stress conditions in relation to wild type plants. Inactive FAAH overexpressors did not have the hypersensitivity to the salt and osmotic stress of the active OE plants and were instead tolerant to these stresses. FAAH2 (faah2) knockouts and FAAH 1 and 2 double knockouts (faah 1+2) were based on some ...
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Alternative Complementation in Partially Schematic Constructions:  a Quantitative Corpus-based Examination of COME to V2 and GET to V2

Alternative Complementation in Partially Schematic Constructions: a Quantitative Corpus-based Examination of COME to V2 and GET to V2

Date: May 2012
Creator: Lester, Nicholas A.
Description: This paper examines two English polyverbal constructions, COME to V2 and GET to V2, as exemplified in Examples 1 and 2, respectively. (1) the senator came to know thousands of his constituents (2) Little Johnny got to eat ice cream after every little league game. Previous studies considered these types of constructions (though come and get as used here have not been sufficiently studied) as belonging to a special class of complement constructions, in which the infinitive is regarded as instantiating a separate, subordinate predication from that of the “matrix” or leftward finite verb. These constructions, however, exhibit systematic deviation from the various criteria proposed in previous research. This study uses the American National Corpus to investigate the statistical propensities of the target phenomena via lexico-syntactic (collostructional analysis) and morpho-syntactic (binary logistic regression) features, as captured through the lens of construction grammar.
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Analysis of Roger-ducasse’s Pastorale Pour Orgue

Analysis of Roger-ducasse’s Pastorale Pour Orgue

Date: May 2012
Creator: Kim, Jung-Won
Description: Pastorale pour Orgue (1909) is Jean Jules Aimable Roger-Ducasse’s only solo organ composition, which demonstrates skillful use of organ colors and demands a virtuoso technique for performance. Writing Pastorale in 1909, Roger-Ducasse synthesized compositional styles and techniques of two very different compositional approaches – impressionism and classicism. This study examines the stylistic characteristics of Pastorale by Roger-Ducasse as examples of both of these influences. the synthesis in Pastorale is primarily evident in the combination of classical forms and generic references with impressionist harmony and color. Thus, examining these musical elements provides hitherto unexplored insights into Pastorale as a master solo organ work of the early twentieth century. the dissertation is divided into four chapters. the first chapter presents the purpose, the significance, and the state of research of the piece. in the second chapter, I examine the traits of classicism through genre, form, thematic variation and other classicist elements of the composition. the third chapter presents the traits of impressionism including harmonic parallelism, extended chords, pedal points, ostinatos, and whole-tone scales. in the fourth chapter, I summarize the study and make a suggestion for further research of the piece.
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