VictorJuiz/thesis huggingface dataset:
A small scale system for releasing a test mass into a Geodesic orbit [electronic resource]

Space-based applications in navigation, aeronomy, geodesy, and fundamental physics such as gravitational wave detection and tests of the Equivalence Principle require ultra-sensitive accelerometers or drag-free apparatuses to either measure disturbing forces (such as solar pressure and drag), or cancel them directly. Most solutions utilize a precisely manufactured Test Mass (TM) that is released into a housing (an empty volume) in a satellite in space, and made to follow a geodesic trajectory, with the host spacecraft shielding the TM from external disturbing forces. Depending on its mass, size, shape, and the launch vehicle environment, the TM may be restrained prior to release. Careful attention must be paid to mechanical and electrical forces that may cause the TM to adhere to its restraints or the walls of the cavity. Mechanisms to overcome the force of adhesion (``stiction'') are typically required. In the current state-of-the-art, either the spacecraft has significant propulsive capability to pull the TM from the restraint using inertial force, or the spacecraft uses some compressed gas or mechanical actuator to separate the TM from the housing. The Laser Interferometer Space Antenna (LISA) is the most salient example, as it uses a pure gold coating that is prone to creep and cold welding, and is therefore naturally prone to adhere to itself; its release process removes the caging force in three stages, finishing with a dynamic retraction of two contacting fingers from opposite faces. After release, the system faces a potential critical failure if the TM comes to rest in contact with the housing wall. The host spacecraft must either employ its propulsive capability to accomplish separation, or use some other actuator. Lacking the capability for the former, LISA will use an electrostatic actuator to arrest the resulting motion, since recontact with the housing could cause an unrecoverable condition. Efforts to advance the aforementioned science have been stymied in part by the enormous costs of fielding full-scale drag-free systems. Stanford has previously proposed a gravitational wave observatory called LAser GRavitational-wave ANtenna at GEo-lunar Lagrange Points (LAGRANGE) that would involve a dedicated mission of three spacecraft to the Earth-moon L3, L4 and L5 Lagrange points. Each spacecraft would host a Gravitational Reference Sensor (GRS) comprised of a spherical test mass in an evacuated cavity. The estimated cost for this mission is almost \

Keywords: Aeronautics and Astronautics.
Advisor: Rock Stephen M. primary advisor. Thesis advisor
Buchman Saps
Lipa John A. advisor. Thesis advisor
A small weak scale from a small cosmological constant [electronic resource]

This thesis discusses a framework in which Weinberg's anthropic explanation of the cosmological constant problem also solves the higgs hierarchy problem. The weak scale is selected by chiral dynamics that controls the stabilization of an extra dimension. When the higgs vacuum expectation value is close to a fermion mass scale (the weak scale), the radius of an extra dimension becomes large, and develops an enhanced number of vacua available to scan the cosmological constant down to its observed value. At low energies, the radion, the particle that controls the size of the extra dimension, necessarily appears as an unnaturally light scalar, in a range of masses and couplings accessible to fifth-force searches as well as scalar dark matter searches with atomic clocks and gravitational-wave detectors. The fermion sector that controls the size of the extra dimension consists of a pair of electroweak doublets and several singlets. These leptons satisfy approximate mass relations related to the weak scale and are accessible to the LHC and future colliders.

Keywords: Physics.
Advisor: Dimopoulos Savas
Graham Peter (Peter Wickelgren) advisor. Thesis advisor
Senatore Leonardo
The social and environmental turn in late 20th century art [electronic resource] : a case study of Helen and Newton Harrison after modernism

Contrary to prominent New York art critic Hilton Kramer and others who have lamented the weakening and death of the historical avant-garde and its fomenting political unrest, this dissertation argues that the avant-garde attitude is very much alive and thriving. The drive to challenge what exists and to locate oneself outside of a dominant paradigm in order to change it most certainly continues after the so-called triumph of modernism in the 1960s. Yet the contemporary avant-garde has undergone two significant changes. For one, to be avant-garde is no longer synonymous with antagonism against academic institutions. Secondly and more importantly, the contemporary avant-garde is no longer constrained by the modernist idea of polarizing revolutions as the driving force of change. Scholars Bruno Latour and Rosi Braidotti provide theoretical frameworks for understanding the work of art, for example, as complementary and not inherently oppositional to the work of science and technology. For Braidotti, nomadic studies across academic domains and cultural geographies are necessary to come to terms with the complexity of the world. To substantiate my argument about the ongoing vitality of the avant-garde, I draw primarily from the archive of two California artists named Helen and Newton Harrison. Born in New York City in 1927 and 1932 respectively, Helen and Newton came of age in the years following the Second World War and married in 1953 with ambitions to develop and use their respective abilities in a way that would benefit society. I present an intimate portrait of the young couple in the postwar era to show that training and self-reflection in those early years is key to appreciating their more than 50-year career in the University of California system, first at UC San Diego and subsequently at UC Santa Cruz, from 1967 to the present. For even within the UC system, the Harrisons have maintained a reputation as self-critical and inquiry-based learners. The latter part of this dissertation is dedicated to an expanded discussion on the Harrisons' nomadic approach to avant-garde aesthetics as it developed in the 1970s on the periphery of theoretical formations and artistic movements, driven by the common goal of realizing a life-support system that bridges social and environmental justice.

Advisor: Frank Zephyr L.
Heise Ursula K. advisor. Thesis advisor
Wight Gail
The social fluency hypothesis [electronic resource]

I introduce the Social Fluency Hypothesis, which stipulates that the ease versus difficulty of social interactions shapes social perceptions and behavior, as well as important psychological, relational, and economic outcomes. I propose that experiencing social interactions as smooth and effortless, rather than as strenuous and taxing, fulfills individuals' fundamental need to form positive social connections and satisfies their preference for fluent mental processes, and that individuals draw important inferences about their interaction partners and relationships from their experiences of social fluency versus disfluency. Six studies demonstrated positive effects of social fluency across a range of circumstances. In Studies 1-3, experiencing social fluency in tacit coordination tasks produced a robust Halo effect, leading individuals to perceive their interaction partners as higher in morality, sociality, and competence; expect positive future interactions; and demonstrate greater behavioral trust, to everyone's benefit. In Studies 4 and 5, social fluency explained unique variance in the subjective value that individuals derived from their negotiations, above and beyond individuals' instrumental outcomes and experiences of procedural justice. Study 6, which focused on the role of social fluency in teamwork, found that cultural and racial diversity in teams was associated with lower levels of social fluency. Social fluency positively predicted psychological need fulfillment and affective commitment toward the team, and mediated the negative effects of diversity on these outcomes. Overall, my theory and findings highlight the significance of social fluency for establishing positive connections with others.

Keywords: Business.
Advisor: Halevy Nir
Flynn Francis J. advisor. Thesis advisor
Neale Margaret Ann
Social Support and Eating Disorders on Instagram: Communication Patterns Amongst Users in the Eating Disorder Recovery Community

It is important to address the increasing growth of a group of people turning to social media to express a stigmatized facet of their identity: their eating disorder. This research focuses on the accounts of people using Instagram as a tool for eating disorder recovery. Instagram provides users the opportunity to disclose sensitive information about their eating disorder recovery experiences, and users can respond in ways that may provide the posters with social support and positive validation in their recovery. I conducted a linguistic analysis of 300 posts within the eating disorder recovery community. I analyzed the language in the posts themselves, the language in the comments received by the post, and the relationship between certain types of posts and their associated comments. Results indicate that discourse of the eating disorder recovery community on Instagram is overwhelmingly positive, demonstrating that users find support and encouragement when disclosing sensitive information about their experiences on Instagram. Posts that are higher in positive tone also receive more positive comments, while posts that are longer, higher in narrative style, higher in clout and confident language, and more authentic receive longer responses. Implications of these results and directions for future research are discussed.

Keywords: Communications
Media Studies
Coterminal Masters Program
eating disorders
social media
Instagram
language
psychological well-being
social support
self-disclosure
Thesis
Advisor: Hancock Jeff
Sources of Parenting Information in Rural China: A Mixed-Method Analysis

Active parenting during the first few years of a child’s life can have significant benefits on child development and set the foundation for learning the skills required in a modern economy. China's rural children are lagging behind their urban counterparts partly because so many rural caregivers do not engage in positive parenting behaviors such as reading, singing, and playing with children when they are infants and toddlers.
This thesis contributes to the existing literature on child development in developing countries by examining sources of parenting information in rural China through case studies in southern Shaanxi province. It uses a mix of quantitative and qualitative methods to identify sources of parenting information for caregivers of infants and toddlers. The children in this study range in age from 6 months to 5 years old, as the paper utilizes samples from a study that began in 2013 as well as currently ongoing studies. The quantitative section analyzes the relationship between certain self-reported sources of parenting information and the number of positive parenting behaviors done. In the qualitative section, this paper also asks rural caregivers about the content of their primary information sources to explore what parenting suggestions caregivers are receiving and what specific parenting lessons caregivers actually retain.
This study suggests multiple ways to improve rural parenting. Encouraging more active parenting behavior through disseminating information on parenting is a low-cost way to improve rural child development outcomes starting from infancy. In addition to media programs better tailored toward encouraging positive parenting behaviors toward infants and toddlers, community-based resources of parenting information can help caregivers learn positive parenting behaviors through social interaction. More local involvement can also help foster a culture of positive parenting. Caregivers need information to help rural children compete in the modern Chinese economy and boost the overall economic well-being of Chinese society as its economy matures.
The author would like to acknowledge the support of Professor Scott Rozelle, the staff and colleagues at REAP and CEEE, and a generous Mentored Global Research Fellowship travel grant from FSI.

Keywords: East Asian Studies
Rural China
Economic Development
Parenting
Mixed-Method
Freeman Spogli Institute
Thesis
Advisor: Rozelle Scott
Spaceborne multibaseline SAR tomography for retrieving forest heights [electronic resource]

Climate change is perhaps the biggest challenge of our time, impacting all life on Earth. During the last 50-100 years, changes in global climate have been much bigger and happened much faster than any such changes the planet has ever seen in recorded human history. Forests play a key role in the global carbon cycle, and hence in the global climate. The yearly carbon flux from forests to atmosphere is still an order of magnitude greater than that from human activities. However, the role of forests remains poorly quantitatively characterized as compared to other ecosystems, due to the practical difficulties in measuring forest biomass stocks globally. Without a quantitative model of the global carbon cycle, sensible policies and actions can be hard to make. Synthetic aperture radar (SAR) is a promising candidate for measuring forest biomass. Since low frequency microwaves penetrate the forest canopy, SAR systems operating at low frequencies can provide essential information in the elevation direction for assessing the forest biomass. In addition, a significant number of satellites equipped with SAR sensors will be scheduled and launched in the next five to ten years. Vast amounts of image data will be generated by current and future spaceborne SAR systems. This calls for new algorithms to exploit the diverse SAR images for forest mapping. In this thesis, we present a new technology, called SAR tomography, to retrieve forest heights. SAR tomography utilizes multiple images acquired from slightly different orbital locations to form a synthetic aperture in the elevation direction. Hence, it can achieve a full three dimentional (3-D) reconstruction of the imaged scenes. We first introduce the basic concepts of the SAR imaging system, and then establish the signal model for SAR tomography. Based on the signal model, we propose the Capon beamformer as the reconstruction algorithm and test its performance via simulation. In the second part, we investigate particular problems when using spaceborne repeat-pass SAR systems on forest areas, including phase errors, forest distributed scatterers and temporal decorrelation. For each problem, we propose a mitigation method and evaluate the performance via simulation. In the last part, we show two case studies using the proposed SAR tomography to reconstruct the elevation profiles in urban and forest areas. The SAR images used in this thesis are from the Advanced Land and Ocean Sensor (ALOS).

Keywords: Electrical Engineering.
Advisor: Zebker Howard A. primary advisor. Thesis advisor
Linscott Ivan advisor. Thesis advisor
Pauly John (John M.) advisor. Thesis advisor
Sparse factorizations and scalable algorithms for differential and integral operators [electronic resource]

Sparse factorizations and scalable algorithms for elliptic differential operators and Fourier integral operators (FIOs) are presented in the defense. The former operators are solved by the distributed-memory hierarchical interpolative factorization (DHIF) whereas the later operators are addressed by the butterfly factorization. By exploiting locality and certain low-rank properties of the elliptic differential operators, the hierarchical interpolative factorization achieves quasi-linear complexity for factorizing the discrete positive definite elliptic differential operator and linear complexity for solving the associated linear system. In this dissertation, the DHIF is introduced as a scalable and distributed-memory implementation of the hierarchical interpolative factorization. The DHIF organizes the processes in a hierarchical structure and keeps the communication as local as possible. The computation complexity is O(N/P log N) and O(N/P) for constructing and applying the DHIF, respectively, where N is the size of the problem and P is the number of processes. Extensive numerical examples are performed on the NERSC Edison system with up to 8192 processes. The numerical results agree with the complexity analysis and demonstrate the efficiency and scalability of the DHIF. The butterfly factorization is a data-sparse approximation for the FIOs as well as other matrices that satisfy a complementary low-rank property. The factorization can be constructed efficiently if either fast algorithms for applying the matrix and its adjoint are available or the entries of the matrix can be sampled individually. For an N by N matrix, the resulting factorization is a product of O(log N) sparse matrices, each with O(N) non-zero entries. Hence, it can be applied rapidly in O(N log N) operations. Numerical results are provided to demonstrate the effectiveness of the butterfly factorization and its construction algorithms. For the kernel matrices of multidimensional FIOs, for which the complementary low-rank property is usually not satisfied due to a singularity at the origin, we extend this factorization by combining it with a multiscale decomposition of the integration domain to overcome the singularity. Numerical results are provided to demonstrate the efficiency of the proposed algorithms as well.

Advisor: Ying Lexing primary advisor. Thesis advisor
Ryzhik Leonid advisor. Thesis advisor
Yang Chao advisor. Thesis advisor
Spatiotemporal receptive field of the elementary motion detector in Drosophila [electronic resource]

Visual motion cues are used by many animals to guide a diverse set of behaviors across a wide range of environments. What algorithm does the brain use to extract these cues? What are the neural circuit elements that implement these algorithms? Using a combination of two photon imaging, genetic techniques and modeling, my work has explored these questions in the visual system of the fruit fly Drosophila. My work demonstrates that the algorithmic basis of motion detection in flies is strikingly similar to that used in the vertebrate visual cortex. In the past decade, Drosophila has emerged as a powerful model for understanding neural circuit function. The strength of this system reflects a unique combination of a rich repertoire of innate and learned behaviors, a highly stereotyped wiring diagram and, critically, the development of a wealth of genetic tools. In Chapter 1, I review how these factors have interacted to advance this field at a remarkable pace. A central goal in the dissection of any neural circuit lies in the identification of the neuron types that are central to the computation of interest. Taking advantage of many of the tools outlined in Chapter 1, Chapter 2 describes the characterization of Tm9, a neuron type that this work demonstrates provides essential input to a specific local motion detector. Surprisingly, using a reverse correlation technique for two-photon imaging, I demonstrated that the spatial receptive field of this cell is much larger than one would have predicted from the anatomy of Tm9, and its functional role in providing input to a local motion detector. This observation reveals both the importance of combining functional and anatomical studies, and enriches our understanding of local motion detectors. Motion vision relies on neurons that respond preferentially to stimuli moving in one, preferred direction over the opposite, null direction. Long-standing theoretical models have made predictions about the computations that compare light signals across space and time to detect motion. In Chapter 3, I describe quantitative measurements of the spatiotemporal receptive fields of the first direction-selective cell types in the fly, T4 and T5, and use these measurements to test alternative theoretical models underpinning this computation. These results argue strongly that flies implement a "motion-energy" model for detecting local motion signals, and that the particular algorithmic implementation used by the fly achieves high selectivity for moving edges by all two- and three-point spacetime correlations relevant to motion in this stimulus class. These studies set the stage for future investigation of the cellular and molecular implementation of this computation.

Advisor: Clandinin Thomas R. (Thomas Robert)
Boxer Steven G. (Steven George)
Ganguli Surya
Smith Stephen J.
Wandell Brian A. advisor. Thesis advisor
State Commercial Bank Pay Structure and Industry Metrics in Response to Bank Branching Deregulation

What was the state-level impact of bank branching deregulation on metrics such as profits, bank size, bank efficiency, and bank employee compensation? Did the timing of deregulation influence its effects? In this essay, I will use the American state-by-state deregulation of bank branching restrictions that occurred between the 1970s and 1990s to analyze the effects of branching regulations on the banking industry within each state. I will use a difference-in-difference analysis of metrics including asset size, profits, income, and indicators of industry efficiency. I test my results with additional controls including state per capita GDP, if the state was a unit banking state, and others. I examine branching deregulation’s effect on workers in the industry by race, gender, and state-level banking structure, as well as the effects of a state deregulating early vs. late. I confirm that branching deregulation lowered wages of workers in commercial banking and that wages of men fell further than those of women, but I counterintuitively find that the wages of Hispanics declined by more than those of whites. I also find that bank-level metrics like asset size rise overall, but that these changes are concentrated in non-unit banking states rather than unit banking states that experienced the greatest regulatory shifts over the time period analyzed. I also construct several measures of industry efficiency and find that, by those measures, deregulation did not make the banking industry more efficient.

Keywords:  Department of Economics
finance
bank branching deregulation
pay structure
bank size
bank efficiency
bank compensation
Stanford Department of Economics
Thesis
Advisor: Haber Stephen