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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
Although aggression is sometimes thought to be maladaptive, evolutionary theories of resource control and dominance posit that aggression may be used to gain and maintain high social prominence within the peer group. The success of using aggression to increase social prominence may depend on the form of aggression used (relational versus physical), the gender of the aggressor, and the prominence of the victim. Thus, the current study examined the associations between aggression and victimization and social prominence. In addition, the current study extended previous research by examining multiple forms of aggression and victimization and conceptualizing and measuring social prominence using social network analysis. Participants were 339 6th grade students from ethnically diverse backgrounds (50.4% girls). Participants completed a peer nomination measure assessing relational and physical aggression and victimization. They also nominated friends within their grade, which were used to calculate three indices of social prominence, using social network analysis. As expected, results indicated that relational aggression was associated with higher social prominence, particularly for girls, whereas physical aggression was less robustly associated with social prominence. Results for victimization were less clear, but suggested that, for girls, those at mid-levels of social prominence were most highly victimized. For boys, results indicated that those both high and low in prominence were most highly relationally victimized, and those at mid-levels of prominence were most highly physically victimized. These findings help inform intervention work focused on decreasing overall levels of aggressive behavior.
ContributorsAndrews, Naomi C. Z (Author) / Hanish, Laura D. (Thesis advisor) / Martin, Carol Lynn (Committee member) / Updegraff, Kimberly A (Committee member) / Arizona State University (Publisher)
Created2013
Description
The study of tomboys offers useful insights for the field of gender development. Tomboys have been the focus of several studies aimed at defining what a tomboy is (Bailey, Bechtold, & Berenbaum, 2002; Plumb & Cowan, 1984; Williams, Goodman, & Green, 1985) and what it means for children and adults who are tomboys (Morgan, 1998; Williams et al., 1985). These and further questions necessitate understanding the correlates and consequences for children exhibiting tomboy behaviors. This study aims to address these gaps in the literature as part of a longitudinal study assessing children's gendered attitudes, relationships, and beliefs. A group of 4th grade girls (N=98), were administered questionnaires asking them about their tomboy gender identity and related behaviors and beliefs. The first research question concerns how we identify tomboys through parent, teacher, and child self-report, and the application of groupings of tomboys as never, sometimes, and always tomboys. It was found that children who fall into different classifications of tomboyism differ on their similarity to own- and other-sex peers on a number of dimensions (e.g. similarity, peer preference, activity preference). Never tomboys had the most similarity and interest to own-sex peers, always tomboys, to other-sex peers, and sometimes tomboys exhibited the most flexibility with interest similar to both own- and other-sex peers. Peer-related adjustment consequences and experiences were considered for the different groups of tomboys, with always tomboys being the most efficacious with other-sex peers, never tomboys being the most efficacious with own-sex peers, and sometimes tomboys showing both own- and other-sex peer interactions and the least exclusion of any group.
ContributorsEngland, Dawn (Author) / Martin, Carol L (Thesis advisor) / Zosuls, Kristina (Committee member) / Updegraff, Kimberly (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
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
Risk and protective factors of peer victimization: the role of preschoolers' affiliations with peers
Description
Studies of peer victimization typically focus on behavioral characteristics of the victims, and frequently overlook the role that peers may play. The current study extended previous research by examining how time spent with two types of peers (externalizing and socially competent) can serve as a risk or protective factor for preschoolers' victimization, and how victimization may differ for boys and girls. In addition, the study explored how affiliating with same-sex and other-sex externalizing and socially competent peers may differentially relate to victimization. Results showed that girls who affiliated with externalizing female peers were significantly more at risk for victimization. In addition, boys and girls who spent time with socially competent male peers (but not female peers) negatively predicted victimization. The results indicate that children's peers, in certain circumstances, may play an important role in victimization. These findings also highlight the importance of considering children's and peers' gender when studying peer processes.
ContributorsClary, Laura (Author) / Hanish, Laura (Thesis advisor) / Martin, Carol (Committee member) / Updegraff, Kimberly (Committee member) / Arizona State University (Publisher)
Created2011