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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
The development of literacy abilities in young children has been a major concern for authorities and teachers in the USA for the last two decades. Significant effort has been devoted to ensure that preschool settings allow and motivate children to engage in literacy activities before entering kindergarten. Research has found that a rich classroom environment in preschool settings enables teachers to encourage literacy interest in children at a young age. While a large amount of research has concentrated in testing the effect of prescriptive modifications in the classroom environment, few have focused on studying the design process and tools that teachers follow to design their classrooms. Public policy and research studies in the United States, mention the design of the classroom environment among teacher's responsibilities, but they do not include practical or methodological guides for them to use. The purpose of this research was to study the design process and tools that teachers use to design literacy rich classrooms in preschool settings. A case study was conducted at the ASU Mary Lou Fulton Teachers College Preschool at Arizona State University. This setting provides a unique opportunity for an exploratory study of this nature because it is a private child development laboratory with a flexible curriculum. Participant observation sessions and in depth semi-structured interviews were conducted to explore the design process used and experienced by the teachers. Findings revealed an iterative and cyclic design process that is repeated over time adjusting to the influence of numerous factors. Results also suggest that teacher's knowledge and beliefs highly influence the organization of their classrooms. Considering these factors as a standpoint allows for further exploration to determine a design process suitable for teachers when designing their learning environments. The use of a structured yet flexible design process, can be a potential tool for educators to design their classrooms, collaborate, document and transmit their knowledge. Although the findings correspond to a specific site studied, the implications are wide reaching as problems and opportunities expressed by the staff are common to other educational settings with similar characteristics.
ContributorsCortes, Catalina (Author) / Patel, Mookesh (Thesis advisor) / Heywood, William (Committee member) / Christie, James (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
Digital Fabrication has played a pivotal role in providing reality to industrial designers' ideas since its first commercial use in late 80's. Making the final prototype of a design project has been the initial assumed use for these technologies in the design process. However, new technology advances in this area offer further opportunities for designers. In this research these opportunities have been carefully explored. This research will be conceptualized through discussing the findings of a case study and theories in the areas of Industrial Design methodology, digital fabrication, and design pedagogy. Considering the span of digital fabrication capabilities, this research intends to look into the design-fabrication relation from a methodology perspective and attempts to answer the question of how the digital fabrication methods can be integrated into the Industrial Design process to increase the tangibility of the design process in very first steps. It will be argued that the above is achievable in certain design topics - i.e. those with known components but unknown architecture. This will be studied through the development of series of hypothetical design processes emphasizing the role of digital fabrication as an ideation tool rather than a presentation tool. In this case study, two differing processes have been developed and given to Industrial Design students to design specific power tools. One of them is developed based on the precedence of digital fabrication. Then the outcome of the two processes is compared and evaluated. This research will introduce the advantages of using the digital fabrication techniques as a powerful ideation tool, which overcomes the imagination problems in many of complicated design topics. More importantly, this study suggests the criteria of selecting the proposed design methodology. It is hoped that these findings along with the advances in the area of additive and subtractive fabrication will assist industrial designers to create unique methodologies to deal with complicated needs both in practice and design education.
ContributorsValamanesh, Roozbeh (Author) / Shin, Dosun (Thesis advisor) / Velasquez, Joseph (Committee member) / Colins, Daniel (Committee member) / Arizona State University (Publisher)
Created2012
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
As the designer is asked to design, create, or simply solve a problem, many factors go into that process. It generally begins with defining the scope or problem that undergoes an iterative process utilizing different tools and techniques to generate the desired outcome. This is often referred to as the design process. Notwithstanding the many factors that influence this process, this study investigates the use of theory for behavior change and its effect on the design process. While social behavioral theories have been extensively discussed in the realm of design, and a well-developed body of literature exists, there is limited knowledge about how designers respond to and incorporate theory into their design process. Fogg’s persuasive design (2003), Lockton’s design with intent (2009) and Tromp’s social implication framework (2011) stand as exemplars of new strategies developed towards design for behavior change that are able to empower designers’ mindsets, providing them with a uniquely insightful perspective to entice change. Instead of focusing on the effectiveness of the design end product, this study focuses on how theory-driven approaches affect the ideation and framing fragment of the design process. A workshop case study with senior design students was utilized with focused observations and post-workshop interviews to answer the research questions. This study contributes by providing a useful method of documenting a behavioral economics theory to the design process in a workshop setting. It also provides insights on how behavioral change theory application can be incorporated in a segment of the design process.
ContributorsAlWazzan, Aysha F. KH. A. A (Author) / Mejia, G. Mauricio (Thesis advisor) / Sanft, Alfred (Committee member) / Fischer, Daniel (Committee member) / Arizona State University (Publisher)
Created2019