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- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- Creators: Peterson, Cory
- Member of: ASU Electronic Theses and Dissertations
Description
There is a popular notion that creativity is highly valued in our culture. However, those "in the trenches," people in creative endeavors that actually produce the acts of creativity, say this is not so. There is a negative correlation between the value stated and the true value placed on creativity by our contemporary culture. The primary purpose of this study was to investigate that correlation as well as a possible contributing factor to this negative correlation--the fear of risk involved in enacting and accepting creativity. The methods used in this study were literature review and interview. An extensive literature review was done, as much has been written on creativity. The review was done in four parts: 1) the difficulty in defining creativity; 2) fear and the fear of creativity; 3) solutions - ways to be, express, and accept creativity; and 4) the plethora of articles written about creativity. Six one-on-one interviews were conducted with creative individuals from a variety of commercial creative endeavors. Creatives in commercial fields were chosen specifically because of their ability to influence the culture. The results of this study showed that the hypothesis, that there is a negative correlation between the value stated and the true value placed on creativity, is true. The fear of risk involved in enacting and accepting creativity as a factor in this dichotomy was also shown to be true.
ContributorsGelman, Howard P (Author) / Heywood, Wil (Thesis advisor) / Patel, Mookesh (Committee member) / Knox, Gordon (Committee member) / Arizona State University (Publisher)
Created2013
Description
Levels of heavy episodic drinking peak during emerging adulthood and contribute to the experience of negative consequences. Previous research has identified a number of trait-like personality characteristics that are associated with drinking. Studies of the Acquired Preparedness Model have supported positive expectancies, and to a lesser extent negative expectancies, as mediators of the relation between trait-like characteristics and alcohol outcomes. However, expectancies measured via self-report may reflect differences in learned expectancies in spite of similar alcohol-related responses, or they may reflect true individual differences in subjective responses to alcohol. The current study addressed this gap in the literature by assessing the relative roles of expectancies and subjective response as mediators within the APM in a sample of 236 emerging adults (74.7% male) participating in a placebo-controlled alcohol challenge study. The study tested four mediation models collapsed across beverage condition as well as eight separate mediation models with four models (2 beverage by 2 expectancy/subjective response) for each outcome (alcohol use and alcohol-related problems). Consistent with previous studies, SS was positively associated with alcohol outcomes in models collapsed across beverage condition. SS was also associated with positive subjective response in collapsed models and in the alcohol models. The hypothesized negative relation between SS and sedation was not significant. In contrast to previous studies, neither stimulation nor sedation predicted either weekly drinking or alcohol-related problems. While stimulation and alcohol use appeared to have a positive and significant association, this relation did not hold when controlling for SS, suggesting that SS and stimulation account for shared variability in drinking behavior. Failure to find this association in the placebo group suggests that, while explicit positive expectancies are related to alcohol use after controlling for levels of sensation seeking, implicit expectancies (at least as assessed by a placebo manipulation) are not. That the relation between SS and stimulation held only in the alcohol condition in analyses separate by beverage condition indicates that sensation seeking is a significant predictor of positive subjective response to alcohol (stimulation), potentially above and beyond expectancies.
ContributorsScott, Caitlin (Author) / Corbin, William (Thesis advisor) / Shiota, Michelle (Committee member) / Chassin, Laurie (Committee member) / Arizona State University (Publisher)
Created2012
Description
Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased efficiency, but at the cost of distortion. Class AB amplifiers have low efficiency, but high linearity. By modulating the supply voltage of a Class AB amplifier to make a Class H amplifier, the efficiency can increase while still maintaining the Class AB level of linearity. A 92dB Power Supply Rejection Ratio (PSRR) Class AB amplifier and a Class H amplifier were designed in a 0.24um process for portable audio applications. Using a multiphase buck converter increased the efficiency of the Class H amplifier while still maintaining a fast response time to respond to audio frequencies. The Class H amplifier had an efficiency above the Class AB amplifier by 5-7% from 5-30mW of output power without affecting the total harmonic distortion (THD) at the design specifications. The Class H amplifier design met all design specifications and showed performance comparable to the designed Class AB amplifier across 1kHz-20kHz and 0.01mW-30mW. The Class H design was able to output 30mW into 16Ohms without any increase in THD. This design shows that Class H amplifiers merit more research into their potential for increasing efficiency of audio amplifiers and that even simple designs can give significant increases in efficiency without compromising linearity.
ContributorsPeterson, Cory (Author) / Bakkaloglu, Bertan (Thesis advisor) / Barnaby, Hugh (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2013
Description
Prior research has looked at the effects of low self-control, unstructured socializing, and risky behaviors on victimization. In previous studies, however, the differences between routine activity and lifestyle theory have been overlooked. The aim of this study is to test the unique characteristics of both theories independently. Specifically, this study addresses: (1) the mediating effects of unstructured socializing on low self-control and victimization and (2) the mediating effects of risky behaviors on low self-control and victimization. Data were collected using a self-administered survey of undergraduate students enrolled in introductory criminal justice and criminology classes (N = 554). Negative binomial regression models show risky behaviors mediate much of the effect low self-control has on victimization. Unstructured socializing, in contrast, does not mediate the impact of low self-control on victimization.
ContributorsWattanaporn, Katelyn A (Author) / Reisig, Michael D (Thesis advisor) / Holtfreter, Kristy (Committee member) / Ready, Justin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Depressive disorders are common among the general populations but are present at an even higher rate among college students. Some research suggests that new stressors during the transition to college may place young adults at increased risk of depressive disorders. In addition, depression in college students has been linked to a variety of risky behaviors such as alcohol use and risky sexual activity. Fortunately, research suggests that religiosity may act as a buffer and lead to lower levels of depressive symptoms and risky behavior. Current research has not adequately examined the relationship between religiosity, depression, and risky behavior among college students. In this study, depressive symptoms were measured using the 20-item Center for Epidemiological Studies Depression scale, while risky behaviors were measured using the section on risky sexual behavior from the Youth Risk Behavior Surveillance survey and the section on alcohol consumption from the Behavioral Risk Factor Surveillance System survey, both developed by the Centers for Disease Control and Prevention. Four questions frequently used in literature to measure critical behaviors and attitudes were used to assess participants' religiosity. It was predicted that engagement in risky behaviors would be associated with higher levels of depressive symptoms while increased religiosity would be associated with lower levels. Additionally, increased religiosity would be associated with lower levels of engagement in risky behavior. Multiple regression analyses revealed that risky behavior were not significantly associated with higher depressive symptoms, while higher church attendance was associated with lower depressive symptoms. Although not considered a risky behavior, ever being forced to have sex was associated with higher depressive symptoms. Linear regression analyses revealed that increased religiosity was associated with increased engagement in risky behavior. These findings suggest that while depressive symptoms and risky behaviors are prevalent among college students, religiosity may act as a buffer and lead to lower levels of depression and risky behavior. Limitations, implications, and future research are discussed.
ContributorsLafarga, Derek Grady (Author) / Vargas, Perla A (Thesis advisor) / Hall, Deborah (Committee member) / Roberts, Nicole (Committee member) / Arizona State University (Publisher)
Created2014
Description
Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly attractive for portable applications. The Digital class D amplifier is an interesting solution to increase the efficiency of embedded systems. However, this solution is not good enough in terms of PWM stage linearity and power supply rejection. An efficient control is needed to correct the error sources in order to get a high fidelity sound quality in the whole audio range of frequencies. A fundamental analysis on various error sources due to non idealities in the power stage have been discussed here with key focus on Power supply perturbations driving the Power stage of a Class D Audio Amplifier. Two types of closed loop Digital Class D architecture for PSRR improvement have been proposed and modeled. Double sided uniform sampling modulation has been used. One of the architecture uses feedback around the power stage and the second architecture uses feedback into digital domain. Simulation & experimental results confirm that the closed loop PSRR & PS-IMD improve by around 30-40 dB and 25 dB respectively.
ContributorsChakraborty, Bijeta (Author) / Bakkaloglu, Bertan (Thesis advisor) / Garrity, Douglas (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
In this thesis, a digital input class D audio amplifier system which has the ability
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
ContributorsBai, Jing (Author) / Bakkaloglu, Bertan (Thesis advisor) / Arizona State University (Publisher)
Created2015
Description
The present study tested the respective mediating effects of sensation seeking and initial level of response (LR) to negative, sedative alcohol effects on the relation between the density of familial history of alcoholism and adolescent alcohol use. Additionally, the present study tested the direct effect of LR to negative, sedative alcohol effects on adolescent drinking over and above the effects of sensation seeking; and also tested the moderating effect of sensation seeking on the relation between level of response negative, sedative alcohol effects and adolescent drinking. Specifically, OLS regression models first estimated the effects of sensation seeking, LR to negative, sedative alcohol effects, and their interaction on alcohol outcomes, over and above the influence of covariates. Indirect effects were then tested using the PRODCLIN method through RMediation. Analyses failed to support sensation seeking as a mediator in the relation between familial history of alcoholism and adolescent drinking, and as a moderator of the relation between LR and adolescent drinking. However, analyses did support a robust direct effect of LR to negative, sedative alcohol effects on adolescent alcohol involvement. A significant mediating effect of initial LR to negative, sedative alcohol effects on the relation between familial alcoholism and adolescent drinking was found, however failed to maintain significance in post-hoc analyses attenuating the downward bias of the measure of initial LR. Initial LR to negative, sedative alcohol effects continued to predict adolescent drinking after attenuating measure bias. These findings strengthen research on initial LR to negative, sedative alcohol effects as a risk for greater alcohol involvement in adolescence, and underscore the complexity of studying the familial transmission of alcoholism in adolescent populations
ContributorsPandika, Danielle (Author) / Chassin, Laurie (Thesis advisor) / Corbin, William (Committee member) / Aiken, Leona (Committee member) / Arizona State University (Publisher)
Created2015