As a very special DC-DC converter, VRM (Voltage Regulator Module) design must follow the fast-developing trend of microprocessors. The design challenges are the high current, high di/dt, and stringent load-line requirement. When the energy is transferred from the input of a VRM, through the VRM, then through the power delivery path to the processor, it needs sufficient capacitors to relay this energy. The capacitors' number appears to be unrealistically large if we follow today's approach for the future processors. High frequency VRM with high control bandwidth can solve this problem, however, the degradation of efficiency makes the conventional buck converter and the hard-switching isolated topologies incapable of operating at higher frequency. The research goal is to develop novel means that can help a high-output- current VRM run efficiently at high frequency. A novel Complementary Controlled Bridge (CCB) self-driven concept is proposed. With the proposed self-driven scheme, the combination of the ZVS technique and the self-driven technique recycles the gate driving energy by making use of the input capacitor of the secondary- side synchronous rectifier (SR) as the snubber capacitor of the primary-side switches. Compared to the external driver, the proposed converter can save driving loss and synchronous rectifier body diode conduction loss. Additionally, compared to the existing level-shifted self-driven scheme for bridge-type symmetrical topologies, its gate signal ringing is small and suitable for high-frequency applications. Although the CCB self-driven VRM reduces the switching frequency-related losses significantly, the conduction loss is still high. Inspired by the current-doubler concept, a novel ZVS current-tripler DC-DC converter is proposed in this work. By utilizing more SR devices to share the current during the freewheeling period, the SR conduction loss is reduced. The current-tripler DC-DC converter has a delta/delta connected transformer that can be implemented with integrated magnetics. The transformer then becomes an integrated magnetic with distributed windings, which is preferred in high current applications. The current-tripler DC-DC converter in fact meets the requirements for the CCB self-driven scheme. The two concepts are then combined with an integrated gate drive transformer. The proposed CCB self-driven concept and current-tripler concept can both be applied to the 12V non-isolated VRMs. The proposed topology is basically a buck-derived soft-switching topology with duty cycle extension and SR device self-driven capabilities. Because there is no isolation requirement, the SR gate driving becomes so simple that the voltage at the complementary controlled bridge can be used to directly drive the SR gate. Both the gate driving loss and the SR body diode conduction loss are reduced. The proposed circuit achieves similar overall efficiency to a conventional 300kHz buck converter running at 1MHz. All the circuits proposed in this dissertation can use coupling inductors to improve both the steady-state efficiency and dynamic performances. The essence of the coupling inductors concept is to provide different equivalent inductances for the steady state and the transient. Moreover, when a current loop becomes necessary to achieve proper current sharing among phases, the current loop sample hold effect will make it difficult to push the bandwidth. The sample hold effect is alleviated by the coupling inductors concept. A small-signal model is proposed to study the system dynamic performance difference with different coupling inductor designs. As the verification, the coupling concept is applied to the 12V non-isolated CCB self-driven VRM and the bandwidth as high as one third of the switching frequency is achieved, which means a significant output capacitor reduction. / Ph. D.

This study investigated whether in a modular technology education (MTE) classroom, gender groupings and learning styles predicted degree of curiosity. Based on the assumption that gender grouping and learning style are factors that influence the degree of curiosity of both individuals and teams, it was hypothesized that a student's learning style (i.e., Accommodating, Converging, Diverging, and Assimilating) and gender grouping (girl/girl, boy/boy, and girl/boy) at the module would be essential elements to consider when measuring the degree of curiosity of learners in MTE classrooms. During a meeting with the deputy superintendent and the technology education supervisor in a mid-sized, suburban public school district in Virginia, three MTE teachers from different schools were identified to participate in this study in the spring of 2004. The sample for this study consisted of middle school students (n = 116; 22 girls and 94 boys, grades 6-8) enrolled in technology education classes using Synergistic SystemsTM modules. Students completed three consecutive MTE activities. This study was conducted in the technology education classroom in three different middle schools. Schools were classified as School A, B or C. Students selected technology education as an elective subject. Kolb's Learning Style Inventory (LSI), Version 3 was used to identify students' preferred learning style. The My Point of View (MyPOV) instrument adapted by Brusic and based on Leherissey's instrument, the State Epistemic Curiosity Scale (SECS), was used to measure individual degree of curiosity. The MyPOV instrument was administered three times; once after each module. Data was analyzed using a multiple linear regression analysis. Descriptive statistical analysis revealed that boys (81%; n = 94) continue to outnumber girls (19%; n = 22) in technology education classrooms. Participants (n = 101) preferred the following learning styles as identified by the LSI: Accommodating (35%), learning from "hands-on" experience, followed by Diverging (25%), preferring to brainstorm ideas, Assimilating (24%), interested in abstract ideas and concepts, and Converging (17%), rather deal with technical tasks and problems. Mean curiosity scores for students were analyzed by school. Results revealed scores from School B were lower than students at Schools A and C as measured by the MyPOV instrument. Mean curiosity scores for students were also analyzed by gender, learning style, and gender grouping. Statistics revealed that scores for girls were higher than boys. An independent-samples t-test was done to evaluate the difference between the means of the genders. According to the analyses, the tests were not significant, t(108) = .932, p = .353 (Score 1), t(110) = 1.282, p = .202 (Score 2), and t(104) = 1.564, p = .121 (Score 3). Overall scores for girl/girl groupings were higher than girl/boy and boy/boy groupings, and scores for girl/boy groupings were higher than boy/boy groupings. A one-way analysis of variance was conducted to evaluate whether the gender grouping means differed significantly from each other. According to the analyses, the F-tests revealed no significant differences in gender groupings, F(2, 97) = 1.65, p = .198 (Score 1), F(2, 95) = .50, p = .608 (Score 2), and F(2, 92) = 1.84, p = .165 (Score 3). Additionally, curiosity scores for students by learning styles showed that participants that preferred to deal with technical tasks and problems or Converging had the highest scores followed by Assimilating, Accommodating and Diverging. A multiple regression analysis was conducted to test if there was a significant relationship between the pairing of students of different gender groupings and different learning styles in the prediction of degree of curiosity. The F-tests revealed that the linear combination of gender groupings and learning styles for the three schools were not significantly related to degree of curiosity, R2 = .09, adjusted R2 = .04, F(5, 86) = 1.65, p = .155 (Score 1), R2 = .09, adjusted R2 = .04, F(4, 79) = 1.84 , p = .130 (Score 2), and R2 = .02, adjusted R2 = -.03, F(4, 73) = .382, p = .821 (Score 3). The t-tests analyses indicated that the Converging learning style, t(79) = 2.06, p =.043, in Score 2 was the only significant predictor variable with this sample. Although it seems that learning style and gender grouping might predict degree of curiosity in MTE laboratories, this assumption was not supported by this study. / Ph. D.

The purpose of this thesis is to develop machinery for calculating Hochschild cohomology groups of certain finite dimensional algebras. So let A be a finite dimensional quotient of a path algebra. A method of modeling the enveloping algebra Ae of A on a computer is presented. Adding the extra hypothesis that A is a monomial algebra, we construct a minimal projective resolution of A over A e. The syzygies for this resolution exhibit an alternating behavior which is explained by the construction of a special sequence of paths from the quiver of A. Finally, a technique for calculating Hochschild cohomology groups from these resolutions is presented. An important application involving an invariant characterization for a certain class of monomial algebras is also included. / Ph. D.

Many applications in biomedicine, research, and industry require recognition agents with specificity and selectivity for their target. Protein engineering enables the design of scaffolds that can bind targets of interest while increasing their stability, and expanding the scope of applications in which these scaffolds will be useful. Repeat proteins are instrumental in a wide variety of biological processes, including the recognition of pathogen-associated molecular patterns by the immune system. A number of successes using alternative immune system repeat protein scaffolds have expanded the scope of recognition agents available for targeting glycans and glycoproteins in particular. We have analyzed the innate immune genes of a freshwater polyp and found that they contained particularly long contiguous domains with high sequence similarity between repeats in these domains. We undertook statistical design to create a binding protein based on the H. magnipapillata innate immune TPR proteins. My second research project focused on creating a protein to bind cellulose, as it is the most abundant and inexpensive source of biomass and therefore is widely considered a possible source for liquid fuel. However, processing costs have kept lignocellulosic fuels from competing commercially with starch-based biofuels. In recent years a strategy to protect processing enzymes with synergistic proteins emerged to reduce the amount of enzyme necessary for lignocellulosic biofuel production. Simultaneously, protein engineering approaches have been developed to optimize proteins for function and stability enabling the use of proteins under non-native conditions and the unique conditions required for any necessary application. We designed a consensus protein based on the carbohydrate-binding protein domain CBM1 that will bind to cellulosic materials. The resulting designed protein is a stable monomeric protein that binds to both microcrystalline cellulose and amorphous regenerated cellulose thin films. By studying small changes to the binding site, we can better understand how these proteins bind to different cellulose-based materials in nature and how to apply their use to industrial applications such as enhancing the saccharification of lignocellulosic feedstock for biofuel production. Biomaterials made from natural human hair keratin have mechanical and biochemical properties that make them ideal scaffolds for tissue engineering and wound healing. However, the extraction process leads to protein degradation and brings with it byproducts from hair, which can cause unfavorable immune responses. Recombinant keratin biomaterials are free from these disadvantages, while heterologous expression of these proteins allows us to manipulate the primary sequence. We endeavored to add an RGD sequence to facilitate cell adhesion to the recombinant keratin proteins, to demonstrate an example of useful sequence modification. / Doctor of Philosophy / Many applications in medicine and research require molecular sensors that bind their target tightly and selectively, even in complex mixtures. Mammalian antibodies are the best-studied examples of these sensors, but problems with the stability, expense, and selectivity of these antibodies have led to the development of alternatives. In the search for better sensors, repeat proteins have emerged as one promising class, as repeat proteins are relatively simple to design while being able to bind specifically and selectively to their targets. However, a drawback of commonly used designed repeat proteins is that their targets are typically restricted to proteins, while many targets of biomedical interest are sugars, such as those that are responsible for blood types. Repeat proteins from the immune system, on the other hand, bind targets of many different types. We looked at the unusual immune system of a freshwater polyp as inspiration to design a new repeat protein to recognize nonprotein targets. My second research project focused on binding cellulose, as it is the most abundant and inexpensive source of biological matter and therefore is widely considered a possible source for liquid fuel. However, processing costs have kept cellulose-based fuels from competing commercially with biofuel made from corn and other starchy plants. One strategy to lower costs relies on using helper proteins to reduce the amount of enzyme needed to break down the cellulose, as enzymes are the most expensive part of processing. We designed such a protein for this function to be more stable than natural proteins currently used. The resulting designed protein binds to multiple cellulose structures. Designing a protein from scratch also allows us to study small changes to the binding site, allowing us to better understand how these proteins bind to different cellulose-based materials in nature and how to apply their use to industrial applications. Biomaterials made from natural human hair keratin have mechanical and biochemical properties that make them ideal for tissue engineering and wound healing applications. However, the process by which these proteins are extracted from hair leads to some protein degradation and brings with it byproducts from hair, which can cause unfavorable immune responses. Making these proteins synthetically allows us to have pure starting material, and lets us add new features to the proteins, which translates into materials better tailored for their applications. We discuss here one example, in which we added a cell-binding motif to a keratin protein sequence.

This is a study of patterning and the connection between the proportions created and destroyed through this process. The analytical study of a pure geometry creates spaces and forms at every scale and in every orientation. These patterns can be layed out in modular panels, whether rotated, overlayed, skewed, or mirrored, in order to create architectural design decisions in plan, section, or elevation. Since the proportions of the module grow exponentially, possibilities are endless in terms of project type and scale. Decisions are made at multiple scales, starting with the human and working up to the building scale, as well as the realm of possibilities that fall in between. The module is acting as a matrix which regulates the articulation every architectural element. It creates order and reason for decision making, whether it be the layout for a cityâ s master plan or a small home. Furthermore, it establishes regularity and control for the organization of spaces. The language of the modular system guides the design development through the grammar established in the particular modular panels. For example, human interactions, seating areas, pathways, and transition spaces naturally belong to certain areas based on the module. This way of working allows for simultaneous planning of the entire site while also organizing the practical and material complexities of the space. / Master of Architecture

With the advent of smart devices, Internet of things and cloud computing the amount of information collected about an individual is enormous. Using this meta-data, a complete profile about a person could be created - professional information, personal information like his/her choices, preferences, likes/dislikes etc. The concept of privacy is totally lost with this gamut of technology. The ability to separate one's on-line identity from their personal identity is near impossible. The conflicting interests of the two parties - service providers' need for authentication and the users' privacy needs - is the cause for this problem. Privacy Preserving Authentication could help solve both these problems by creating valid and anonymous identities for the users. And simply by proving the authenticity and integrity of this anonymous identity (without revealing/exposing it) the users can obtain services whilst protecting their privacy. In this thesis, I review and analyze the various types of PPA schemes leading to the discussion of our new scheme 'Lightweight Anonymous Attestation with Efficient Revocation'. Finally, the scenarios where these schemes are applicable are discussed in detail. / Master of Science / With the advent of smart devices, people are almost always connected to the Internet. These smart devices and applications collect information about the user on a massive scale. When all such meta-data are put together, a complete profile of the user - professional and personal information, his/her choices, preferences, likes/dislikes etc. could be created. And all this data is stored somewhere on the Internet. The concept of privacy loses its meaning as this entity knows more about the user than they do themselves. The main reason for this is the inability to separate one’s on-line identity from their personal identity. Service providers need to authenticate the users - the process by which one entity is assured of the identity of the second entity it is interacting with - to ensure only valid members are allowed to use their service. This leads to invasion of the user’s privacy/anonymity as authentication often needs details like address, date-of-birth, credit card details etc. Privacy Preserving Authentication could help solve both these problems by creating valid but anonymous identities for the users. PPA works by issuing the users a secret credential if they can prove their identity. And simply by proving the authenticity and integrity of these secret credentials (without revealing/exposing it) the users can obtain services whilst protecting their privacy. In this thesis, I review and analyze the various types of PPA schemes leading to the discussion of our new scheme Lightweight Anonymous Attestation with Efficient Revocation. Finally, the application scenarios where these schemes are applicable are discussed in detail.

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The use of computers in the modern world has become prevalent in all aspects of life. The size of these machines has decreased dramatically while the capability has increased exponentially. A special DC-DC converter called a VRM (Voltage Regulator Module) is used to power these machines. The VRM faces the task of supplying high current and high di/dt to the microprocessor while maintaining a tight load regulation. As computers have advanced, so have the VRM's used to power them. Increasing the current and di/dt of the VRM to keep up with the increasing demands of the microprocessor does not come without a cost. To provide the increased di/dt, the VRM must use a higher number of capacitors to supply the transient energy. This is an undesirable solution because of the increased cost and real estate demands this would lead to in the future. Another solution to this problem is to increase the switching frequency and control bandwidth of the VRM. As the switching frequency increases the VRM is faced with efficiency and thermal problems. The current buck topologies suffer large drops in efficiency as the frequency increases from high switching losses. Resonant or soft switching topologies can provide a relief from the high switching loss for high frequency power conversion. One disadvantage of the resonant schemes is the increased conduction losses produced by the circulating energy required to produce soft switching. As the frequency rises, the additional conduction loss in the resonant schemes can be smaller than the switching loss encountered in the hard switched buck. The topology studied in this work is the 12V non-isolated ZVS self-driven presented in [1]. This scheme offered an increased efficiency over the state of the art industry design and also increased the switching frequency for capacitor reduction. The goal of this research was to study this topology and improve the magnetic design to decrease the cost while maintaining the superior performance. The magnetics used in resonant converters are very important to the success of the design. Often, the leakage inductance of the magnetics is used to control the ZVS or ZCS switching operation. This work presents a new improved magnetic solution for use in the 12V non-isolated ZVS self-driven scheme which increases circuit operation, flexibility, and production feasibility. The improved magnetic structure is simulated using 3D FEA verification and verified in hardware design. / Master of Science

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Youth with disabilities often struggle to transition into new areas of life; many of these youth have difficulty finding and keeping jobs, making friends, and living independently. The present study evaluated the effects of accessing an online guide detailing how to access supports in one's community. The goal was to increase knowledge of community support options for four students with intellectual and learning disabilities from a transition-support program in the Mountain West. The guide included information on applying for a job, making friends by joining a social club, and finding where to attend church. Results indicated that each student learned how to better access community supports following usage of the guide. Participants also report improved community support following this training. Each participant stated that the intervention meets their goals and that they do not find it aversive to use. Implications for practitioners and practical applications of this research to transition programs are discussed.