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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
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
The purpose of this study was to examine whether dispositional sadness predicted children's prosocial behavior, and whether empathy-related responding (i.e., sympathy, personal distress) mediated this relation. It was hypothesized that children who were dispositionally sad, but well-regulated (i.e., moderate to high in effortful control), would experience sympathy versus personal distress, and thus would engage in more prosocial behaviors than children who were not well-regulated. Constructs were measured across three time points, when children were 18-, 30-, and 42-months old. In addition, early effortful control (at 18 months) was investigated as a potential moderator of the relation between dispositional sadness and empathy-related responding. Separate path models were computed for sadness predicting prosocial behavior with (1) sympathy and (2) personal distress as the mediator. In path analysis, sadness was found to be a positive predictor of sympathy across time. There was not a significant mediated effect of sympathy on the relation between sadness and prosocial behavior (both reported and observed). In path models with personal distress, sadness was not a significant predictor of personal distress, and personal distress was not a significant predictor of prosocial behavior (therefore, mediation analyses were not pursued). The moderated effect of effortful control was significant for the relation between 18-month sadness and 30-month sympathy; contrary to expectation, sadness was a significant, positive predictor of sympathy only for children who had average and low levels of effortful control (children high in effortful control were high in sympathy regardless of level of sadness). There was no significant moderated effect of effortful control on the path from sadness to personal distress. Findings are discussed in terms of the role of sadness in empathy-related responding and prosocial behavior as well as the dual role of effortful control and sadness in predicting empathy-related responding.
ContributorsEdwards, Alison (Author) / Eisenberg, Nancy (Thesis advisor) / Spinrad, Tracy (Committee member) / Reiser, Mark R. (Committee member) / Arizona State University (Publisher)
Created2012
How gender typicality moderates the relation between preadolescents' empathy and acceptance by peers
Description
Previous research has shown that highly empathic children are generally more emotionally positive, sociable, and altruistic compared to their less empathic peers (Miller & Jansen op de Haar, 1997). These traits and behaviors linked with empathy have been associated with positive outcomes such as popularity in the peer group (Decovic & Gerris, 1994). However, a negative relation between these constructs has been found when studied in the context of preadolescence for boys (Oberle, Schonert-Reichl, & Thomson, 2010), suggesting a potential moderating effect of gender typicality since empathy is classified as a communal and therefore stereotypically feminine trait. The current study examines the relation between the constructs of gender, empathy, gender typicality, and peer acceptance in a preadolescent sample, and mixed findings suggest differential effects of empathy on peer acceptance for preadolescent boys and girls. Future research should continue examining these differential effects for boys and girls throughout childhood and adolescence.
ContributorsPetersen, Shawna Michelle (Author) / Fabes, Richard A. (Thesis advisor) / Martin, Carol L (Committee member) / Miller, Cindy F (Committee member) / Arizona State University (Publisher)
Created2015
Description
“shiFT: An Exploration of Empathy” is a document detailing the process of
creating the evening length dance performance, “shiFT,” through the theoretical,
somatic, kinesthetic and choreographic research of empathy. This research specifically
addressed the ability to consciously take on an empathetic perspective and the change
that must occur within oneself to co-create empathy. It focused on the factors that
impede empathetic function and the role of vulnerability in experiencing empathy.
Throughout the creation of this concert, the choreographer employed empathy building
exercises and concentrated creative processes constructed from her research into the
neurological, emotional and physical aspects of empathy with a cast of ten dancers.
Choreographer and dancers worked collaboratively to create an empathetic
environment, a pre-show film installation titled GREY MATTER, and the culminating
evening length concert piece “shiFT.”
creating the evening length dance performance, “shiFT,” through the theoretical,
somatic, kinesthetic and choreographic research of empathy. This research specifically
addressed the ability to consciously take on an empathetic perspective and the change
that must occur within oneself to co-create empathy. It focused on the factors that
impede empathetic function and the role of vulnerability in experiencing empathy.
Throughout the creation of this concert, the choreographer employed empathy building
exercises and concentrated creative processes constructed from her research into the
neurological, emotional and physical aspects of empathy with a cast of ten dancers.
Choreographer and dancers worked collaboratively to create an empathetic
environment, a pre-show film installation titled GREY MATTER, and the culminating
evening length concert piece “shiFT.”
ContributorsWitt, Rebecca (Author) / Fitzgerald, Mary (Thesis advisor) / Standley, Eileen (Committee member) / Heywood, William (Committee member) / Arizona State University (Publisher)
Created2018
Description
This study investigated the relation between Sensory Processing Sensitivity (SPS) temperament and depression, and whether such a relation might be further influenced by the indirect effects of parenting environment and empathic personal distress. A moderated mediation model was proposed to explain the underlying relations among SPS, depression, parenting environment and empathic personal distress. That is, greater levels of SPS temperament might predict higher levels of empathic personal distress, which then leads to increasing likelihood of experiencing depression. Moreover, it was predicted that this mediation relation might be significantly stronger under a less positive parenting context. The present study recruited 661 participants from a U.S. university and implemented questionnaires in an online survey. There was a significant main effect of SPS temperament in predicting empathic personal distress and depression, such that the more sensitive individuals reported higher empathic personal distress and depression. There also was a significant main effect of parenting environment on depression, where more positive parenting was associated with less depression. Empathic personal distress was found to partially mediate the relation between SPS and depression. That is, the association between SPS and depression could be partially explained by empathic personal distress. However, parenting environment did not moderate the main effect of SPS temperament on depression, the main effect of SPS on empathic personal distress, or the mediation model.
ContributorsYang, Wenxi (Author) / Miller, Paul A. (Thesis advisor) / Hall, Deborah L. (Committee member) / Roberts, Nicole A. (Committee member) / Arizona State University (Publisher)
Created2019
Description
Increasing counselor trainees’ self-efficacy for multicultural counseling competence (MCC) is an essential part of their professional development to serve racially and ethnically diverse clients effectively. The present study examined the impact of multicultural training and the effects of a brief mindfulness intervention, compared to a control condition, on counselor trainees’ self-reported ethnocultural empathy and MCC. Data obtained from a sample of masters (n = 63) and doctoral (n = 23) counselor trainees were analyzed through a series of linear multiple hierarchical regression analyses. Consistent with previous research, results revealed that multicultural training significantly predicted scores of self-reported multicultural counseling knowledge and empathic feeling. The mindfulness intervention significantly predicted self-reported multicultural counseling knowledge. There was a significant interaction between condition (i.e., mindfulness intervention or control) and previous multicultural training when examining ethnocultural empathy’s empathic feeling and expression subscale. Specifically, trainees with lower levels of multicultural training who received the mindfulness intervention scored higher on empathic feeling compared to those in the control condition, while at higher levels of multicultural training there were no differences across condition. Implications for future research and counselor training are discussed.
ContributorsSmith, Bethany E (Author) / Spanierman, Lisa B (Thesis advisor) / Tran, Alisia G. T. (Committee member) / Arredondo, Patricia (Committee member) / Arizona State University (Publisher)
Created2018
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 previous research literature was reviewed on how perpetrator's group membership and individuals' racial identity impact intergroup attitude and behavior, as well as factors contribute to intergroup bias on individuals' empathy level. This study was designed to extend the existing research on intergroup relations by exploring the effect of perpetrator's ingroup/outgroup membership and the strength of racial identity on people's empathy toward the outgroup victims. A web-based survey was disseminated and administrated at a southwest university. One hundred and six Caucasian American college students who completed the survey and met the criterion of eighteen years old or older were involved in this study. Participants were randomly assigned to read one of two target stories and one distracter story, and reported their empathy level toward each story. And then the participants' strength of racial identity was measured.
Controlling for demographic variables, regression analyses revealed that, as expected, the interaction of the perpetrator's group membership and individuals' racial identity significantly predicted the level of empathy toward the outgroup victim. When the perpetrator was an ingroup member, people who highly identified with their group exhibited less empathy for the outgroup victim. However, perpetrator's membership and the strength of racial identity failed to predict individuals' outgroup empathy separately.
Controlling for demographic variables, regression analyses revealed that, as expected, the interaction of the perpetrator's group membership and individuals' racial identity significantly predicted the level of empathy toward the outgroup victim. When the perpetrator was an ingroup member, people who highly identified with their group exhibited less empathy for the outgroup victim. However, perpetrator's membership and the strength of racial identity failed to predict individuals' outgroup empathy separately.
ContributorsOuyang, Yunzhu (Author) / Miller, Paul A. (Thesis advisor) / Hall, Deborah L. (Committee member) / Salerno, Jessica M. (Committee member) / Arizona State University (Publisher)
Created2015
Description
Engineering ethics is preoccupied with technical failure. To ameliorate the risk that engineering works might either blow up or fall down, the engineering code of ethics provides guidance of how engineers should conduct themselves. For example, the Fundamental Canons in the National Society of Professional Engineers code of ethics states that engineers should hold paramount the health, safety and welfare of the public. As a result, engineering designs meet basic human needs such as food, water and shelter -- at risks that are generally considered acceptable. However, even safe designs fail to meet our needs ranked higher in Maslow's hierarchy -- such as belonging, esteem and self-actualization. While these have historically not been ethical priorities, increasing expectations in developed countries now include more complex ethical concepts such as sustainability and social justice. We can expect these trends toward higher and more complex human needs to continue -- although the profession seems ill-prepared. We argue that an empathic approach to engineering design is necessary to meet these higher needs of developed and developing societies. To guide engineers towards this approach, we propose a pluralistic interpretation of empathy grounded in an understanding of the three parts of the mind: cognitive, affective, and conative. In fact, product designers already use empathy in their design processes. However, an exemplar of an empathic design is harder to find in civil engineering disciplines. This paper discusses an example of the Hoover Dam Bypass, which resulted in an award-winning design and construction that improved traffic flow, reduced vulnerability to terrorist attack, and accounted for historical factors and environmental impacts. However, this technical success is an empathic failure. Although project leaders commissioned ethnographic studies to understand the impact the bridge would have on the local Native American populations and their cultural sites, the eventual design showed little consideration of the concerns that were revealed. For engineering designs such as bridges, other infrastructure and systems to meet the needs of the various populations in which they serve, engineers need to incorporate empathy into their designs.
ContributorsVortherms, Kaitlin (Author) / Seager, Thomas (Thesis advisor) / Tracy, Sarah (Committee member) / Spierre/Clark, Susan (Committee member) / Arizona State University (Publisher)
Created2016