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- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- 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
Postwar suburban sprawl resulted in environmental consequences that engendered backlash from those concerned about the quality life in the places they lived, played, and worked. Few cities grew as rapidly as Phoenix and therefore the city offers an important case study to evaluate the success and limits of environmentalism in shaping urban growth in the postwar period.
Using three episodes looking at sanitation and public health, open space preservation, and urban transportation, I argue three factors played a critical role in determining the extent to which environmental values were incorporated into Phoenix's urban growth policy. First, the degree to which environmental values influenced urban policy depends on the degree to which they fit into the Southwestern suburban lifestyle. A desire for low-density development and quality of life amenities like outdoor recreation resulted in decisions to extend municipal sewers further into the desert, the creation of a mountain preserve system, and freeways as the primary mode of travel in the city. Second, federal policy and the availability of funds guided policies pursued by Phoenix officials to deal with the unintended environmental impacts of growth. For example, federal dollars provided one-third of the funds for the construction of a centralized sewage treatment plant, half the funds to save Camelback Mountain and ninety percent of the construction costs for the West Papago-Inner Loop. Lastly, policy alternatives needed broad and diverse public support, as the public played a critical role, through bond approvals and votes, as well as grassroots campaigning, in integrating environmental values into urban growth policy. Public advocacy campaigns played an important role in setting the policy agenda and framing the policy issues that shaped policy alternatives and the public's receptivity to those choices.
Urban policy decisions are part of a dynamic and ongoing process, where previous decisions result in new challenges that provide an opportunity for debate, and the incorporation of new social values into the decision-making process. While twenty-first century challenges require responses that reflect contemporary macroeconomic factors and social values, the postwar period demonstrates the need for inclusive, collaborative, and anticipatory decision-making.
Using three episodes looking at sanitation and public health, open space preservation, and urban transportation, I argue three factors played a critical role in determining the extent to which environmental values were incorporated into Phoenix's urban growth policy. First, the degree to which environmental values influenced urban policy depends on the degree to which they fit into the Southwestern suburban lifestyle. A desire for low-density development and quality of life amenities like outdoor recreation resulted in decisions to extend municipal sewers further into the desert, the creation of a mountain preserve system, and freeways as the primary mode of travel in the city. Second, federal policy and the availability of funds guided policies pursued by Phoenix officials to deal with the unintended environmental impacts of growth. For example, federal dollars provided one-third of the funds for the construction of a centralized sewage treatment plant, half the funds to save Camelback Mountain and ninety percent of the construction costs for the West Papago-Inner Loop. Lastly, policy alternatives needed broad and diverse public support, as the public played a critical role, through bond approvals and votes, as well as grassroots campaigning, in integrating environmental values into urban growth policy. Public advocacy campaigns played an important role in setting the policy agenda and framing the policy issues that shaped policy alternatives and the public's receptivity to those choices.
Urban policy decisions are part of a dynamic and ongoing process, where previous decisions result in new challenges that provide an opportunity for debate, and the incorporation of new social values into the decision-making process. While twenty-first century challenges require responses that reflect contemporary macroeconomic factors and social values, the postwar period demonstrates the need for inclusive, collaborative, and anticipatory decision-making.
ContributorsDi Taranto, Nicholas (Author) / Hirt, Paul (Thesis advisor) / Vandermeer, Philip (Committee member) / Smith, Karen (Committee member) / Arizona State University (Publisher)
Created2015
Description
This thesis explores the implications that the outcome of a certain U.S. lawsuit involving antiquities could have on practices and programs in the United States, related to cultural heritage and history. This paper examines the Rubin et al case, which sought to attach a collection of ancient Persian artifacts (known as The Persepolis Tablets) as a source of legal compensation. Presented as a case study, and using primary and secondary research sources, this paper analyzes the Rubin et al lawsuit and the factors that led to its initiation, and seeks to determine how and why adverse consequences could result from its final ruling. This thesis demonstrates that the final decision in the lawsuit could leave a negative impact on a number of practices related to cultural heritage in the United States, especially with regards to cultural and academic institutions such as museums and universities.
ContributorsAhouraiyan, Taraneh (Author) / Warren-Findley, Jannelle (Thesis advisor) / Warrren-Findley, Jannelle (Committee member) / Thompson, Victoria (Committee member) / Smith, Louis (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
Food banks are the foundation of the emergency food network, and while their chief mission is to mitigate hunger, the rise in obesity and other diet-related diseases among clientele has incited the need for better nutritional control with regards to procurement of inventory at food banks. The purpose of this research was to determine if procured inventory at United Food Bank in Mesa, Arizona could meet minimum MyPlate recommendations for a typical food bank client and what implications the results could have for future policy. Inventory data was obtained from United Food Bank for fiscal year 2013-2014 and analyzed utilizing the MyPlate Analysis Program to determine contributions of each food category to MyPlate recommendations. Inventory was separated by MyPlate food category and analyzed to determine contribution towards a meal built around MyPlate recommendations. Results showed that the inventory could meet the minimum requirements for protein and grains for a family of four for at least three days, the amount of time an emergency food box is designed to last. On the contrary, the inventory did not meet minimum vegetable, fruit or dairy requirements. These results indicate that typical food bank inventory does not meet USDA MyPlate recommendations and that having nutritional policy in place could potentially drive donations and purchases to enhance the nutritional quality of future food bank inventory.
ContributorsLick, Linda (Author) / Bruening, Meredith (Thesis advisor) / Vaughan, Linda (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2015
Description
Informal public transport is commonplace in the developing world, but the service exists in the United States as well, and is understudied. Often called "dollar vans", New York's commuter vans serve approximately 120,000 people every day (King and Goldwyn, 2014). While this is a tiny fraction of the New York transit rider population, it is comparable to the total number of commuters who ride transit in smaller cities such as Minneapolis/St Paul and Phoenix. The first part of this study reports on the use of commuter vans in Eastern Queens based on a combination of surveys and a ridership tally, all conducted in summer 2016. It answers four research questions: How many people ride the vans? Who rides the commuter vans? Why do they ride commuter vans? Do commuter vans complement or compete against formal transit? Commuter van ridership in Eastern Queens was approximately 55,000 with a high percentage of female ridership. Time and cost savings were the main factors influencing commuter van ridership. Possession of a MetroCard was shown to negatively affect the frequency of commuter van ridership. The results show evidence of commuter vans playing both a competing and complementary role to MTA bus and subway transit. The second part of this study presents a SWOT analysis results of commuter vans, and the policy implications. It answers 2 research questions: What are the main strengths, weaknesses, opportunities and threats of commuter vans in Eastern Queens? and How do the current policies, rules and regulations affect commuter van operation? The SWOT analysis results show that the commuter van industry is resilient, performs a necessary service, and, with small adjustments that will help reduce operating costs and loss of profits have a chance of thriving in Eastern Queens and the rest of New York City. The study also discusses the mismatch between policy and practice offering recommendations for improvement to ensure that commuter vans continue to serve residents of New York City.
ContributorsMusili, Catherine (Author) / Salon, Deborah (Thesis advisor) / King, David (Committee member) / Kelley, Jason (Committee member) / Arizona State University (Publisher)
Created2017
Description
There is a gap between today's scientific advances and their application--between what is known and what is actually being done. This gap occurs because of the process of knowledge translation required to digest research findings for policymakers and practitioners. Studies have repeatedly shown that because of this "know-do" gap, approximately one-half of patients in the United States and Europe are not receiving care according to the most recent scientific evidence. Children are a medically unique and underserved population that stands to be most affected by this gap. Therefore, in this study, the research-practice gap in the pediatric field was calculated and discussed in the context of knowledge brokers, who facilitate opportunities for knowledge translation. Article mentions from the journal Pediatrics were identified in policy documents and analyzed for the years 2010, 2013, and 2016 with the use of the Altmetric platform as a quantitative means of identifying patterns and drawing conclusions about the knowledge translation gap in pediatrics. Altmetric is a bibliometric tool that offers viable insights into the types of impact not covered with traditional methods of citation analysis. The expert policymaking bodies that cited the Pediatrics articles in their policy documents were coded, categorized, and subcategorized to clarify how and where Pediatrics research is ultimately being used to create health policy and to discover whether the gap is similar or different between the various types of policymaking organizations. This allowed the quantitative findings to be nested within a qualitative context. It took a mean of 7.1 years for research to reach the point of policy uptake for practitioners, with a range of 0-32.8 years. There were more international policy mentions than U.S. mentions, but information made its way through the knowledge translation process more quickly in the United States than it did elsewhere. In fact, nearly 40% of articles were cited in policy fewer than five years after original publication. The gap in pediatrics is thus significantly shorter than the 17-year average reported in the literature. However, knowledge brokerage activities performed by technical communicators are continually needed to build links between research, policy applications, and practice.
ContributorsBabiar, Heather (Author) / D'Angelo, Barbara (Thesis advisor) / Brumberger, Eva (Committee member) / Maid, Barry (Committee member) / Arizona State University (Publisher)
Created2018
Description
Advocacy groups work across many aspects of “death with dignity” practice and treatment, and provide insight across multiple aspects of “death with dignity”. This study argues that key advocacy groups in the American death with dignity movement influenced the broader conceptualization of death with dignity in a way that makes patients more able to achieve it. This influence has been a dynamic process across different periods of practice starting the discussion of “death with dignity” in 1985 through today, although this thesis extends only to 2011. The question in this study is how do the three main historical advocacy groups in the US: the Hemlock Society, Compassion in Dying, and Compassion and Choices, conceptualize death with dignity with regards to patient and doctor relationship, legal and policy factors, and medical technologies and protocols? This study found that the Hemlock Society (1980-2005) characterized death with dignity as a terminally ill patient being able to “self-deliver” from suffering via autoeuthanasia regardless of medical community approval or legality. Compassion in Dying (1993-2007) characterized death with dignity as involved advocacy work with terminal patients and their communities to pursue palliative care and hospice up to the point of assisted death. This organization was also involved in the passing of Oregon Death with Dignity Act. Compassion and Choices (2007-present) characterized death with dignity similarly to Compassion in Dying but also advocated for adequate management of pain and suffering symptoms in palliative care to prevent people from desiring death over the illness. Conceptualizing death with dignity is important for understanding why patients want death with dignity and better accommodating their end of life needs when they are suffering with terminal illness.
ContributorsCohan, Hailey Elizabeth (Author) / Ellison, Karin (Thesis advisor) / O'Neil, Erica (Committee member) / Piemonte, Nicole (Committee member) / Arizona State University (Publisher)
Created2019
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
2023 has been a record-breaking year for legislation aimed at restricting and even criminalizing access to gender affirming care for minors. In response to these legislative efforts, many advocates rely on invocations of medical authority to defend the right of individuals to access gender affirming care. However, this reliance on the pathologization of transgender identity both reaffirms stigmatization of transgender identity as mental illness as well as forecloses on opportunities to affirm access to gender affirming care otherwise. The purpose of this research is to use disability justice scholarship, predominantly crip theory, to analyze these legislative efforts in-depth beyond the predominant critique offered by the medical-model. I demonstrate that these legislative moves to ban access to gender affirming care are part of a larger effort to prevent a trans future more broadly. Trans childhood has become a particularly fruitful site for this political action due to the ways in which normativities relating to time, biological plasticity, and capacity shape the way that their bodies are understood. I term those individual bodies which have such characteristics of non-normative temporalities, plasticity, and capacity/incapacity grafted onto them become “bodies of normative intervention” and explore how they become the laboratory sites for producing population-wide normative interventions. This legislative effort to restrict access to gender affirming care for minors represents a broader effort to legislate a trans future out of existence through the strategic targeting of trans children. This robs society of valuable trans knowledge and experience.
ContributorsMills, Raegan Lenore (Author) / Hurlbut, Ben (Thesis advisor) / Brian, Jennifer (Thesis advisor) / Hlava, Terri (Committee member) / Arizona State University (Publisher)
Created2023