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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
This study is intended as a catalyst to inspire new ways of thinking by educators, school administrators, and museum educators. It is a study of six K-12 art teachers who have both the technology and the opportunity at their school campuses to use collaborative videoconferencing as part of their instruction in multicultural art, linking their students to the resources of the Smithsonian Institute in Washington D.C. The art unit used for the purpose of this study was Latina/o art. Findings show the Smithsonian American Art Museum program to be of high quality and useful i students see the connection between identity of self and multicultural art.
ContributorsFosnight, Estelle (Author) / Erickson, Mary (Thesis advisor) / Stokrocki, Mary (Committee member) / Young, Bernard (Committee member) / Arizona State University (Publisher)
Created2013
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
Description
This qualitative research study was about art teachers’ perceptions and practices of cultural diversity and its implications for the U.S. The purpose of the study was to provide a rationale for the need for learning institutions to recognize the changing demographics and to respond to the potential educational implications of the new demographics as they prepare their art teachers to educate diverse student populations. The study involved six art teachers who teach in schools with students from diverse cultural backgrounds. To collect data, interviews with participants were transcribed and analyzed. Analysis of teacher interviews showed the importance of helping art teachers to obtain the skills, attitudes, dispositions and knowledge to work effectively with students from diverse cultural backgrounds. The richness of the descriptions obtained from the interviews provides insight into multicultural art education in schools. The results of this study might help art educators and policy makers understand the need for more awareness of multicultural education and its impact on teachers, parents, administrators and students. This study concludes with suggestions on art education, including the need to develop curriculum that are inclusive to multicultural students, especially Islamic from cultures. Art education programs in universities should produce teachers who are prepared for the cultural diversity in their classrooms. It is essential that teachers accept and implement changes in their communities, in their schools, and in their teaching in order to better serve students of culturally diverse backgrounds.
ContributorsMasrya, Mawadah (Author) / Young, Bernard (Thesis advisor) / Stokrocki, Mary (Committee member) / Erickson, Mary (Committee member) / Arizona State University (Publisher)
Created2016
Description
Although women of color have increased their presence in the workplace, many obstacles restricting career opportunities still exist. It is important that mental health professionals contribute in providing interventions to increase career opportunities for women of color. The purpose of this research is to add to the repertoire of interventions by studying the irrational career beliefs of Black women. This research utilizes the Believe It! program, an online career development program that focuses on altering irrational/maladaptive career beliefs that can prevent young females from pursuing career opportunities. An early study of Believe It! found it to be effective for Caucasian females, however the effects for minority females were less clear. The current study re-examined the effectiveness of Believe It! for minorities by altering the appearance of the animated character within the program. It was hypothesized that young African American women interacting with African American animated agents would display greater rationality in terms of career beliefs compared to young African American women interacting with Caucasian animated agents. Forty-four African American girls between the ages of eleven to fifteen were pre-tested with a battery of assessment devices addressing the irrationality of the girls' career beliefs. The measures included the Career Myths Scale, the Career Beliefs Inventory, the Occupational Sex-role Questionnaire, and the Believe It! measure. Four to eight days later, participants engaged in the online Believe It! Program; they were randomly assigned to either a matched condition (viewing the program with an African American animated agent) or a mismatched condition (viewing the program with a Caucasian animated agent). After completion of the intervention, participants were post-tested with the same assessment battery. MANCOVA and ANCOVA analyses showed that participants in the matched condition consistently benefitted from the matched intervention. Implications for this research are discussed.
ContributorsWebster, Jacqueline (Author) / Horan, John J (Thesis advisor) / Atkinson, Robert (Committee member) / Homer, Judith (Committee member) / Arizona State University (Publisher)
Created2010
Description
Employing ethnographic content analysis of 110 top Hip-Hop songs of 2004-2014 from Billboard and BET awards, this study investigated the most popular value themes of 4th generation Hip-Hop music and compared the messages of female and male rap artists. The 12 most frequently referenced messages included: 1) Celebration of Personal Success (77%), 2) Urban Consciousness, Identity, and Pride (68.8%), 3) Sexual Prowess/Seductive Power (62.1%), 4) Recreational Drug Use (54.9%), 5) Ready and Willing to Become Violent (48.8%), 6) Sexual Objectification (48.2%), 7) Reappropriation of Stigma Labels (36.4%), 8) Drive and Ambition (28.5%), 9) Self-Objectification (28.5%), 10) Struggle and Resilience (20%), 11) Providing Resources in Exchange for Sex (15.1%), and 12) Providing Sex in Exchange for Resources (10.3%). Male and female rap artists expressed similar messages. However, female rap artists were more likely to reappropriate stigma labels, promote self-objectifying lyrics, and depict themselves as providing sex in exchange for resources in their lyrics than were male rap artists. Male rap artists were more likely to sexually objectify others in their lyrics and depict themselves as providing resources in exchange for sex than were their female counterparts. Implications for counseling and suggestions for future research are discussed.
ContributorsMartinez-Morales, Vanessa (Author) / Kinnier, Richard (Thesis advisor) / Kurpius, Sharon (Committee member) / Homer, Judith (Committee member) / Arizona State University (Publisher)
Created2015