Matching Items (9)
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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
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
Male victims of commercial sexual exploitation and sex trafficking have been neglected in research literature, and little is known about the experiences of male victims of sex trafficking and sex trading. This research study aims to explore the experiences of male sex trafficking and sex trading in a large urban southwestern city to identify incidences, available resources, and needed services for male sex traders. Research was conducted at a drop-in center for homeless youth ages 18-24 in a large urban city in the southwest. A total of 13 males between the ages of 18 and 24 were interviewed. The results of this study revealed that male sex trafficking does exist among the homeless youth population, that childhood sexual victimization appears to be a precursor to sex trading later in life, that there are limited resources for males that participate in sex trading, and that more research needs to be done within this population.
ContributorsVan Kleeck, Cynthia (Author) / Roe-Sepowitz, Dominique (Thesis advisor) / Risley-Curtiss, Christina (Committee member) / Sheade, Ryan (Committee member) / Arizona State University (Publisher)
Created2014
Description
An asset-based approach to vulnerability, as presented in Voices of the Poor: Can Anyone Hear Us? and World Development Report 2000/2001: Attacking Poverty, provides a possible theoretical framework for understanding vulnerability to human trafficking. Case studies, field studies and narratives of human trafficking provide evidence that the assets of victims of trafficking play a significant role in human trafficking. This appears to be true both with regard to how traffickers exploit victim assets and with regard to how successful human trafficking prevention efforts are implemented. By exploring and further establishing this connection, I hope to provide evidence that a model of human trafficking acquisition incorporating elements of victim assets and the assets of communities deserves field-testing. Such field-testing will hopefully confirm the deep connection between assets and human trafficking activity and establish the necessary connections anti-trafficking activists will need to create a predictive version of the model with regard to individual vulnerability to human trafficking. Lastly, I argue that, provided the connection between human trafficking vulnerability and victim asset levels holds, an asset-based approach provides a rhetorical framework to resist policies that compromise asset levels of particularly vulnerable populations.
ContributorsFees, Kyle Elliot (Author) / Stancliff, Michael (Thesis advisor) / Behl, Natasha (Committee member) / Murphy Erfani, Julie (Committee member) / Arizona State University (Publisher)
Created2015
Description
Interviews of nine managers within the U.S. Department of Labor's Wage and Hour Division's Western Region were conducted by a researcher who also works as a Wage and Hour Investigator. The intention of this research was to survey the differences in trafficking-related training and experience throughout the region, to examine the role of the Wage and Hour Division in human trafficking casework, and to explore potential areas for growth. This thesis recommends that upper level agency management produces standards for training, interagency engagement, and procedures and also provides suggestions for best practices and effective enforcement.
ContributorsNorberg, Katherine Joanne (Author) / Stancliff, Michael (Thesis advisor) / Simmons, William (Committee member) / Téllez, Michelle (Committee member) / Arizona State University (Publisher)
Created2011
Description
The crime of human trafficking has received increased national attention over the past decade. However, the subject of human trafficking is rarely mentioned in criminal justice and criminology curricula in colleges and universities. This study discusses findings from a review of listed courses in 100 criminology and criminal justice bachelor degree programs in colleges and universities in the United States. Implications for further research, including examining criminal justice education programs outside of academe, are discussed. The author advocates adding courses on human trafficking in criminology and criminal justice curricula and makes recommendations for undergraduate criminology and criminal justice education.
ContributorsZhilina, Tatyana (Author) / Stancliff, Michael (Thesis advisor) / Bernat, Francesc (Committee member) / Vaughan, Suzanne (Committee member) / Arizona State University (Publisher)
Created2011
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
This study examined the effects of victim characteristics and past life experiences on attributions of blame to human trafficking victims in hypothetical scenarios. Specifically, this study investigates the main and interaction effects of the victim’s race, age, and victimization disclosure on outsider’s perceptions of blameworthiness. A factorial vignette survey that provided information about a victim altering her race (Black or White), current age (15 or 21), and availability of victimization disclosure was given to a university-based sample (N = 592). Utilizing three-way analysis of variance (ANOVA) for the analysis, the results showed that the main effects of the victim’s age and victimization disclosure significantly influenced attributions of blame. The results also indicated that there are significant two-way and three-way interactions. The conclusion highlights the importance of these findings as well as avenues for future research and potential programming.
ContributorsPuckett, Audrey Lynn (Author) / Maguire, Edward (Thesis advisor) / Fox, Kate (Committee member) / Roe-Sepowitz, Dominique (Committee member) / Arizona State University (Publisher)
Created2020
Description
Human trafficking is the exploitation of people for the use of labor, services or commercial sex. Trafficking varies in different regions of the world, with different vulnerabilities and risk factors that differ based on a number of factors. Thousands of people, most often minors or young adults, are trafficked throughout the United States every year and face a unique set of problems that relate to the black market of ‘sex for sale.’ Human trafficking is not an entirely ‘secret’ issue, in fact most people in the US are aware that it happens in their state and have some recollection of the magnitude of the crisis. With so much data on the topic from documentaries, news stories and nation-wide organizations spreading awareness, we wonder why this underground industry continues to spread and thrive across the country. Through private interviews, surveys, and data collection, I was able to use my field research to determine that there are numerous misconceptions about human trafficking. Inaccurate data, social media trends, Hollywood films and mass fear create a false narrative about the actual risks of trafficking that parents and children should be aware of. Rather than knowing the root causes and predispositions that make children vulnerable to trafficking, we are looking for what television or social media says to be looking for. My study uses qualitative research to gather a unique type of data to understand what traffickers are looking for so that we can collectively keep each other safe from a growing industry that thrives on ignorance and vulnerabilities. By gathering information from those working with survivors and ideas believed by parents living in the US, I am able to determine what misconceptions are most often spread and compare to true data about the crisis in the US.
ContributorsHeath, Heather Allison (Author) / Smith-Cannoy, Heather (Thesis advisor) / Redeker-Hepner, Trisha (Thesis advisor) / Funk, Kendall (Committee member) / Arizona State University (Publisher)
Created2023