VictorJuiz/thesis huggingface dataset:
Closed-Loop Design of Brain-Machine Interface Systems

Brain-machine interface (BMI) systems show great promise for restoring motor function to patients with motor disabilities, but significant improvements in performance are needed before they will be clinically viable. Moreover, BMIs must ultimately provide long-term performance that can be used in a variety of settings. One key challenge is to improve performance such that it can be maintained for long-term use in the varied activities of daily life. Leveraging the closed-loop, co-adaptive nature of BMI systems may be particularly beneficial for meeting these challenges. BMI creates an artificial, closed-loop control system, where the subject actively contributes to performance by volitional modulation of neural activity. In this work, we explore closed-loop design methods for BMI, which exploit the closed-loop and adaptive properties of BMI to improve performance and reliability./nWe use a non-human primate model system, where subjects controlled 2-dimensional virtual cursors using spiking activity recorded from chronic electrode arrays implanted in motor cortex. We first explore closed-loop decoder adaptation (CLDA), which adapts the decoding algorithm as the user controls the BMI to improve performance. We present a CLDA algorithm that can rapidly and reliably improve performance regardless of the initial decoding algorithm, which may be particularly useful for clinical applications with paralyzed patients. We then demonstrate that CLDA can be combined with neural adaptation, and that leveraging both forms of adaptation may be useful for producing high-performance BMIs that can be maintained long-term. We also show that neural adaptation may be important for BMIs used in multiple contexts by exploring simultaneous motor and BMI control. We also show that both the selection of the neural signals for control will influence BMI operation. Finally, we explore neural representations of movement dynamics to explore alternative control signals for BMI. All together, this work shows the power of closed-loop engineering of BMI systems for motor neuroprostheses.

Advisor: Carmena, Jose M
Search for resonant WZ to lvll production using 13 fb^{-1} in \sqrt{s} = 8 TeV p-p collisions with the ATLAS detector

This dissertation presents a search for a resonant state decaying to a W and a Z boson/nusing events with three charged leptons (electrons or muons) and missing transverse energy./nThe search is performed using proton-proton collisions at a center-of-mass energy of 8 TeV,/nproduced by the LHC and measured by the ATLAS detector in 2012. This data sample/ncorresponds to an integrated luminosity of 13.{fb^{−1}. Events are selected with reconstructed/nW and Z bosons found at similar rapidity and large angular separation. The invariant/nmass of three leptons and missing energy is calculated, assuming on-shell W production,/nand compared to the Standard Model expectation. No significant excess is observed and the/nresults are interpreted as cross-section times branching ratio limits for two specific models./nIn the context of an Extended Gauge Model, a W′ boson is excluded at a 95 % confidence/nlevel for masses below 1180 GeV. In the context of a Low Scale Technicolor model, two-/ndimensional limits are set for values of the technipion and technirho mass between 200 GeV/nand 1000 GeV. These limits are generalizable to any model predicting a narrow resonance/nthat decays to a W and a Z boson.

Advisor: Shapiro, Marjorie
Law, Politics and Markets of Corporate Governance: Institutional Investors' Influence

Abstract/nLaw, Politics and Markets of Corporate Governance:/nInstitutional Investors' Influence/nby/nStephen Davis Carniglia/nDoctor of Philosophy in Jurisprudence and Social Policy/nUniversity of California, Berkeley/nProfessor Robert A. Kagan, Chair/nThis dissertation research project examines the role of institutional investors in influencing the corporate governance rules applicable to U.S. public companies, through an interview study of institutional investors and their expert corporate governance advisers, as well as a detailed review of the comments submitted to the SEC in connection with a proposal to regulate the proxy advisory firms which advise institutional investors. The key issue continues to be the "agency problem" identified by Berle and Means in the 1930's: the tendency of management to serve their own interests rather than investors' interests./nDespite a long-standing debate over whether corporate law evolves to serve managers or investors, there is substantial evidence that the resulting legal environment has permitted corporate governance rules which tend to entrench management and increase its discretionary powers. This has led to significant increases in management compensation, which has led to behavior intended to protect management and enhance compensation. A long history of political and legal involvement by business and management interests has served to protect the status quo in most cases. Dispersed shareholders have been at a disadvantage in corporate governance because of the collective action problem; their individual interests are small compared to those of corporate managers./nThe growth of institutional ownership of U.S. corporate shares led many commentators to predict that these new shareholders would have the resources and interests to counter management interests, curb excesses, and reform corporate governance. While they have had some success, institutional investors have not been as influential as expected and executive compensation has grown substantially at the same time as institutional ownership increased./nThis research shows that institutional investors want important changes in corporate governance, especially in aligning management's interests with shareholders', but they have failed to match management's actions in coordination, lobbying, political contributions, litigation, and public relations. It found evidence that institutional investors barely use their vast economic power to influence corporate governance. It found that a significant impediment is a striking mismatch in personality traits and motivation of corporate governance professionals compared to corporate managers, although proxy advisory firms provide an unheralded role in coordinating institutional corporate governance efforts and positions. It concludes that the agency problem is unlikely to be solved without significant increases in institutional investors' political resources and coordination, and without a new mobilizing force.

Advisor: Kagan, Robert A.
Language Brokering among Immigrant Latino Families: Measurement Validation, Moderating Variables, and Youth Outcomes

Language brokering can be defined as interpretation bilingual children provide for their parents or other monolingual persons. Although language brokering is a common practice among immigrant communities, it is still a growing body of literature in need of theoretical and measurement development. This study addressed these gaps in the extant literature in the following ways: (a) the Language Brokering Measure - IV (LBM-IV; Anguiano, 2009) was revised based on empirical examinations of its psychometric properties; (b) a comprehensive theoretical framework of language brokering was put forth, and (c) a theoretical model developed from this framework, which examined the effects of various language brokering experiences and family obligation on perceived stress and academic achievement, was empirically tested using latent variable regression. Participants included 362 Spanish-speaking, Latino adolescents from immigrant families. Structural validity results supported a three-factor structure of the LBM-IV, which included the division of language brokering experiences according to high-stakes, everyday, and low-stakes translating situations. Model-testing results indicated that translating in High-Stakes situations negatively affected the academic achievement of language-brokering youth, while translating in Everyday situations positively affected it. Furthermore, youth who had higher levels of family obligation reported lower levels of perceived stress, higher academic achievement, and were buffered against the negative effects of High-Stakes translating duties on perceived stress. Implications of these results for language brokering scale development and theory development are discussed.

Advisor: Worrell, Frank C
Essays on the Economics of Education

An important question that many educators face is how to motivate students to study. Many programs in the US and other countries give cash or award incentives to encourage students to exert more effort. In the following three essays, I explore different alternatives to raise student effort, which in turn should raise student achievement, measured in grades and standardized test scores./nIn my first essay, I propose that the grading system affects the incentives to exert effort among students. For this purpose, I build a model where students maximize their utility by choosing effort. I investigate how student effort changes when there is a change in the grading system from absolute grading to relative grading. I use data from college students in Chile who faced a change in the grading system to test the implications of my model. My model predicts that, for low levels of uncertainty: (i) total effort is higher with absolute grading; (ii) low ability students exert less effort with absolute grading, and; (iii) high ability students exert more effort with absolute grading. The data confirms that there is a change in the distribution of effort, although I don't find a change in the total level of effort./nOne results from the model discussed in the first essay is that high ability students exert higher effort under higher standards, but a high standard might have a negative impact on low ability students, who could give up and hence exert zero effort. So in my second essay, I explore whether higher grading standards have an effect on student achievement measured by standardized tests. Grading standards are measured as the school intercept in a regression of standardized test scores on grades. Using data from 8th graders in Chile, I find that higher standards have a positive average effect on standardized test scores. This effect is positive for the percentiles 25, 50 and 75 of the achievement distribution and is larger for the 25th percentile./nIn my third essay, I explore whether the gender of the teacher has an impact on student achievement and if this impact is different for boys and girls. Again, I use data from 8th graders in Chile. Within-student comparisons based on these data indicate that/nassignment to a same-gender teacher significantly improves the achievement of girls but doesn't improve the achievement of boys. I find that the effect is larger for subjects that are traditionally considered male dominated, and for girls whose mothers have low levels of education, which is consistent with a role model hypothesis.

Advisor: Card, David
Cooperative Multiplexing in Wireless Relay Networks

Wireless networks are experiencing an explosive growth in the number of users and the demand for data capacity. One of the methods to improve capacity is to use tighter cooperation between terminals. In order to design a cooperative wireless link, several theoretical as well as practical challenges need to be addressed. In this dissertation we develop tools for the design of practical cooperative links that perform very close to fundamental limits./nUsing the tools of information theory, we begin by showing that cooperative relaying provides additional degrees-of-freedom for communication. For a simple network with a single-antenna source, single-antenna half-duplex relay and a two antenna destination, we show that cooperation allows the link throughput to increase approximately by a factor of 2./nThis gain is achievable using the recently introduced quantize-map-and-forward (QMF) cooperation scheme. However, QMF requires joint decoding of multiple information streams at the destination. The computational complexity of joint decoding is prohibitive for practical implementation. We address this problem by developing a low-complexity practical coding and system design framework for QMF relaying. The framework presents several pragmatic design choices to achieve cooperative degree-of-freedom gains in practice. The framework uses a combination of LDPC and LDGM codes decoded jointly over a low complexity factor graph. Signal processing requirements at all terminals are shown to have linear time complexity. Density evolution tools are developed for the design of specialized linear codes and mapping functions. Based on these tools, we demonstrate the design of cooperative links that perform within 0.5-1.0dB of information-theoretic limits.

Advisor: Nikolic, Borivoje
Mixed Conduction in Rare-Earth Phosphates

Abstract/nMixed Conduction in Rare-Earth Phosphates/nby/nHannah Leung Ray/nDoctor of Philosophy in Materials Science and Engineering/nUniversity of California, Berkeley/nProfessor Lutgard C. De Jonghe, Chair/nThe goal of this work is to gain a better fundamental understanding of mixed electronic and protonic conduction in rare earth phosphates. Specifically, the controlled introduction of a small amount of electronic conductivity is found to enhance the proton conductivity of the (La,Ce) orthophosphates. This discovery could change the way that materials for electrolyte applications are designed./n/nRare earth orthophosphates for the past 20 years have been investigated for their applications as intermediate temperature fuel cell electrolytes. They are known to conduct protons, electron-holes, and oxygen vacancies, under different conditions. The rare earth phosphates are tunable in many different ways. The materials can be aliovalently doped; their metal to phosphorous ratio can be varied; and using different synthesis methods can have a large effect on their conduction properties. In addition, the (La,Ce) orthophosphates are an ideal model system for investigating mixed conduction. Systematically varying the Ce content tunes the contribution of electronic component of the total conduction./nIn this work, the defect chemistry of the system is discussed; several synthesis methods for the rare earth phosphate compositions are carried out; different methods for identifying the dominant charge carriers are described; and the effect of increasing the Ce content upon the total conductivity in single atmospheres and in the fuel cell configuration is measured.

Advisor: De Jonghe, Lutgard C
Carnaval, Samba Schools and the Negotiation of Gendered Identities in São Paulo, Brazil

The behaviors and interactions that enact specific gender identities are assumed by many Brazilians to be "natural." Within the context of samba schools, the distribution of specific performance roles has always been informed by the assumption that there are natural feminine and masculine spaces. Thus, samba school members have well defined performance roles that are hierarchically structured. In this dissertation, I argue that gendered identities are constructed and articulated in the process of cultivating specific performance roles within samba schools. I am particularly interested in highlighting the ways in which specific femininities and masculinities came to be taught, learned and naturalized in the lives of samba school members, as they engage in strategies of social- and self-discipline while preparing for the carnaval parade each year. Central to my argument is the idea that dance/musical competence is intertwined with notions about the physical body and the nurturing of particular character dispositions. By analyzing specific historical moments, discourses and samba schools' micro-practices and disciplinary methods, I show how performance roles are determined and defined by perceptions regarding gender as well as age, body type, skin color, behavior and bodily deportment. Furthermore, I demonstrate how the act of dancing and/or playing music in distinctive ways has become, at once, critical markers of specific femininities and masculinities, and also the way through which one learns how to be feminine or masculine. Finally, I explore how some samba school members have been able to construct alternative capacities for themselves by examining the circumstances that have allowed these participants to operate differently despite the given assumptions about the division of gendered identities.

Advisor: Guilbault, Jocelyne
Partial Flexibility in Routing and Scheduling

In many service, production, and traffic systems there are multiple types of customers requiring different types of servers, i.e., different services, products, or routes. Often, however, a proportion of the customers are flexible, i.e., they are willing to change their type in order to achieve faster service, and even if this proportion is small, it/nhas the potential of achieving large performance gains. We study partial flexibility in multi-server queueing systems. Some (dedicated) arrivals are obliged to use a particular station, while others (flexible) have the ability to use any of the stations./nWe first consider the optimal routing policy for the flexible customers under various settings. Flexible customers should be routed by the decision maker to one of queues upon arrival. When the only information available upon arrival is the queue lengths, then "Join the Shortest Queue" (JSQ) has been shown to be optimal in a variety of contexts. We generalize earlier results on the optimality of "Join the Shortest Queue" for flexible arrivals to the following: arbitrary arrivals where only a subset are flexible, multiple-server stations, and abandonments. Our optimality results are very strong; we minimize the queue length process in the weak majorization sense. When the actual workload at each queue is known upon arrival but the required work of the arriving customer is unknown, we show that routing flexible customers to the queue with the shortest workload, known in the literature as the "Join the Shortest Work" (JSW) policy, is optimal for general arrival and service processes./nSecondly, we study the scheduling problem in an alternate design where the flexible customers have a separate queue to wait. We show that the optimal scheduling policy is "Dedicated Customers First" (DCF) policy under various settings. This design is better than the routing design in terms of system performance; however it is not a good design in terms of fairness, because flexible customers face long waiting times./nFinally we consider the marginal impact of customer flexibility. We present our new results showing that the stationary expected waiting time is decreasing and convex in the proportion of flexible customers. Although convexity in the proportion of flexible customers is intuitive, it does not hold in the strong sense that monotonicity holds, and it is surprisingly difficult to prove. We develop a new approach that combines marginal analysis with coupling to show convexity in the stationary mean waiting time. Our results reinforce the idea that a little flexibility goes a long way.

Advisor: Righter, Rhonda L
Colonial Faces: Beauty and Skin Color Hierarchy in the Philippines and the U.S.

"Colonial Faces: Beauty and Skin Color Hierarchy in the Philippines and the U.S." investigates how perceptions of beauty, skin color hierarchy, the globalization of beauty standards, and the ongoing colonial relationship between the Philippines and the U.S. are related. This project takes a transnational approach in order to compare beauty and skin color hierarchy among Filipinas in the Philippines and in the diaspora. It examines how beauty standards are constructed locally and globally, and how Filipino women in the Philippines and the U.S. respond to these standards. It addresses the popularity of skin-lightening products in the Philippines and looks at how Filipino American women are affected by this practice. This project also explores how skin-lightening products are marketed and analyzes the role of mixed-race models in this marketing.

Advisor: Choy, Catherine Ceniza
Mechanisms for Fluorescence Blinking and Charge Carrier Trapping in Single Semiconductor Nanocrystals

Time-resolved fluorescence is measured for single semiconductor nanocrystals with a range of compositions and morphologies. The fluorescence is observed to blink on and off intermittently, a process known as fluorescence blinking or intermittency. Despite its wide-spread occurrence for nanocrystals, the exact cause of the blinking behavior is still highly debated. A large number of blinking models have been proposed, all of which predict charge carrier trapping to play a major role in blinking. Fluorescence blinking is measured as a function of excitation intensity for CdSe/ZnS quantum dots, and two different power-dependent behaviors are observed for the on- and off-states. While the on-state power dependence supports a multi-exciton ionization-induced charge trapping mechanism, the off-state data supports a fluctuating trapping/de-trapping rate that depends on a single exciton. This suggests that multiple charge trapping mechanisms may play a role for a single nanocrystal. Investigation of the fluctuation-based mechanism was extended to several nanocrystal compositions and morphologies through the measurement of on-state memory, or correlations of subsequent on-state durations, and distributed kinetics. The on-state memory was found to decrease for nanocrystals with less distributed blinking kinetics, indicating that both may originate from the same fluctuation-based blinking mechanism. Furthermore, reproducing this correlation using Monte-Carlo simulations required the combined effects of two blinking mechanisms. Consistent with the power-dependent results, a single rate charge trapping process and the fluctuation-based mechanism were considered. Finally, the simultaneous measurement of fluorescence blinking and decay data for CdSe/ZnS quantum dots led to the direct observation of trapping rate fluctuations occurring during the off-state. This result supports one class of blinking models that relies on rate fluctuations, and not long-lived trap states, to account for blinking. Taken together, these results help to construct a larger-scale picture of fluorescence blinking that relies on the combined effects of several charge trapping processes. Fluorescence blinking was also applied to probe the interaction of single CdSe/CdS nanocrystals and a new class of chalcogenidometalate ligand complexes. Hole trapping was identified as the dominant process affecting the optical properties of this composite system.

Advisor: Leone, Stephen R
Enantio- and Diastereoselective Additions to Nitroalkenes via N-Sulfinyl Urea Organocatalysis

Abstract/nEnantio- and Diastereoselective Additions to Nitroalkenes via N-Sulfinyl Urea Organocatalysis/nby/nKyle Lawrence Kimmel/nDoctor of Philosophy in Chemistry/nUniversity of California, Berkeley/nProfessor Robert G. Bergman, Chair/nChapter 1. An introduction to my work with sulfinyl ureas as a new class of hydrogen-bonding catalysts is presented. The conception of this type of catalysis is discussed, and highlights in the sulfinyl urea-catalyzed additions of thioacetic acid and Meldrum's acid are presented./nChapter 2. The sulfinyl urea-catalyzed enantioselective addition of thioacetic acid to a broad range of &beta- and cyclic &alpha,&beta-disubstituted nitroalkenes is described. This method is shown to be useful for accessing pharmaceutically relevant 1,2-aminothiol products./nChapter 3. The enantio- and diastereoselective addition of cyclohexyl Meldrum's acid to &beta- and &alpha,&beta-disubstituted nitroalkenes is presented. This method is demonstrated to be a viable route to &gamma-amino acid derivatives with multiple stereocenters./nChapter 4. The conjugate addition-enantioselective protonation of Meldrum's acid with terminal nitroalkenes is described. This process utilizes a sulfinyl urea catalyst that is chiral solely at the sulfinyl group. Rapid conversion of the addition products to pharmaceutically relevant &alpha,&gamma-disubstituted &gamma-lactams is demonstrated.

Advisor: Ellman, Jonathan A