VictorJuiz/thesis huggingface dataset:
Covariance estimation and graphical models for infinite collections of random variables [electronic resource]

Estimating correlations for a large collection of random variables is an important part of an enormous number of modern applications of data science, statistics, and mathematics. In particular, it is often necessary to work with either an infinite collection of variables (such as in a spatial-temporal field) or to approximate a large high-dimensional finite stochastic system with an infinite-dimensional system. Two of the most common techniques used for high dimensional covariance estimation are Markov random fields, also known as graphical models, and positive definite functions, also known as covariance functions, but neither of these approaches has been adequately explored for use with infinite collections of random variables. In particular, the theory of Markov random fields is highly dependent on the finiteness of the graphs used to represent the random variables, and while covariance functions can be used for high-dimensional covariance estimation in certain contexts, they generalize poorly to non-spatiotemporal collections of random variables and have other drawbacks (e.g., they may induce poorly conditioned covariance matrices). This dissertation attempts to expand the mathematical theory of Markov random fields to enable infinite dimensional applications, and explores the relationship between graphical approaches to covariance estimation and positive definite functions.

Keywords: Mathematics.
Advisor: Rajaratnam Balakanapathy primary advisor. Thesis advisor
Dembo Amir advisor. Thesis advisor
Ying Lexing advisor. Thesis advisor
Creativity Machines: How Video Game Hardware Characteristics Influence Software Variety

In writing this thesis, I explored the following research questions: What is the relationship between a console’s design characteristics and the types of video games developers tend to create for it? Do increases in hardware capabilities (i.e., processing power and storage capacity) correspond to increases in the creativity of video game developers, as reflected by increased software variety? Is there a relationship between increased software variety and console sales? Most specifically, this thesis evaluated the hypothesis that unconventional hardware corresponds to increased developer creativity. I found that ‘unconventional’ consoles (i.e., consoles that upended preexisting hardware paradigms in one or more ways) corresponded to increased genre variety, but processing power and media storage capacity had little correlation to genre variety. I also identified a correlation between genre variety and console unit sales: consoles with greater genre variety tended to outsell consoles with lower genre variety.

Keywords: Brandon Evans
Stanford University
Program in Science Technology and Society
STS
Honors Thesis
Video Game
Software Variety
Thesis
Advisor: Crum Poppy
Creatures of two worlds [electronic resource] : small robots and hybrid aerial-terrestrial locomotion

This thesis is about the design and analysis of small, mobile robots that operate in various combinations of air and surface locomotion. Our goal is to create robots that traverse unstructured environments with speed and efficiency. Our analysis focuses on the physics of the transitions between states that make this kind of locomotion possible. Throughout the work, we will find connections with the natural world, where operation in multiple modes and at small scales defines the operational life of many animals. We note how advances in processors, sensors, and actuators have made it easier to create robots which explore these spaces, and look forward to the potential future growth of inexpensive, active platforms.

Keywords: Mechanical Engineering.
Advisor: Cutkosky Mark R. primary advisor. Thesis advisor
Lentink David
Waldron Kenneth J. advisor. Thesis advisor
Cross-cultural understanding [electronic resource] : an examination on its measurement, teachability, and application

Markus and Kitayama's seminal work (1991) on the independent and interdependent self-way has greatly benefited psychologists in understanding and interpreting cultural differences observed in the East and the West in the past decades. But it is unclear how much insight lay people have about this framework. How well do people from independent and interdependent cultures understand each other? I studied this question with two cultures that had been used frequently in past research: The mainstream American culture (an example of independent culture) and the traditional Chinese culture (an example of interdependent culture). I developed a scale that measured independent/interdependent cultural understanding, and used it to examine and compare Chinese and American people's understanding of each other (Study 1). I found that, in general, American participants were more "accurate" in their cross-cultural understanding than Chinese participants, and while Americans tended to stereotype the Chinese culture, the Chinese were more likely to project their own cultural values on Americans. I then looked at whether we could teach people about the independent/interdependent framework to help them gain insight into the other culture (Study 2). I found that learning about the framework led American participants to exaggerate the difference between Chinese and American culture. Lastly, I selected one cross-cultural setting to examine whether greater insight would lead to better cross-cultural interaction (Study 3), and found that cultural insight did not readily translate into culturally appropriate behaviors. Taken together, these studies begin to look at lay people's understanding of culture and of other cultures. It creates a space for research and discussion of how psychologists can best help people to understand and appreciate other cultures and "culture" itself as a construct that shapes and is shaped by every one of us.

Keywords: Psychology.
Advisor: Walton Gregory M. (Gregory Mariotti) primary advisor. Thesis advisor
Markus Hazel Rose advisor. Thesis advisor
Tsai Jeanne Ling advisor. Thesis advisor
Cross-species immune system atlas [electronic resource]

Animal models are an integral part of the drug development and evaluation process. However, they are unsurprisingly imperfect reflections of humans. With the rise of targeted and biological therapeutics, it is increasingly important that we understand the molecular differences in immunological behavior of humans and model organisms. Thus, we profiled a large number of healthy humans, along with the model organisms most similar to humans: rhesus and cynomolgus macaques and African green monkeys, and the most widely used mammalian model: mice. Immune cell signaling responses to a panel of 15 stimuli were measured using CyTOF mass cytometry to read out universal signaling and phenotyping panels. We found numerous instances of different immune signaling events occurring between species with likely effects on evaluation of therapeutics. We frame these differences in the context of the immune system as a modular network.

Keywords: Microbiology and Immunology.
Advisor: Nolan Garry P. primary advisor. Thesis advisor
Arvin Ann M. advisor. Thesis advisor
Engleman Edgar G. advisor. Thesis advisor
Greenberg Harry B. advisor. Thesis advisor
Relman David A. advisor. Thesis advisor
Crystal structure determinations of xenon nanoparticles and X-ray induced transient lattice contraction in the solid-to-plasma transition [electronic resource]

With the advent of free-electron lasers, the electronic and mechanical properties of single nanoparticles can be studied with intense, femtosecond x-ray bursts. X-ray coherent diffractive imaging techniques on single, non-periodic structures under the `diffraction-before-destruction' principle proves atomic resolution is within reach, but before the full potential of free-electron lasers is realized, a complete understanding of x-ray--matter interaction is of utmost importance. Xenon nanoclusters in the gas phase are ideal model systems for investigating light--matter interactions and x-ray induced electronic and structural effects. The experiments presented in this work were performed on such systems at the Coherent X-ray Imaging (CXI) Instrument of the Linac Coherent Light Source (LCLS). So far, serial femtosecond crystallography (SFX) experiments at the LCLS have been limited to particles larger than 100 nm, but in this study these techniques are extended to investigate nanoparticles 10--30 nm in diameter. In a first experiment, xenon nanoparticles were illuminated with hard x-ray flashes. When properly oriented in the ~100 nm FEL focus, Bragg scattering from the xenon crystals was recorded on a high resolution x-ray pixel array detector. Crystallite size, determined from Bragg peak shape, conform well to known scaling parameters. Structural determinations highlight the `crystal structure problem' for rare gas clusters, and suggest complex growth dynamics. Namely, the xenon cluster crystal structure is highly dependent on particle size, with more observed crystal faults as the particle size is increased. The data suggests a hexagonal close-packed (hcp) structure emerges from stacking faults in the face-centered cubic (fcc) structure of large clusters. All matter irradiated by intense FEL pulses is ionized within femtoseconds. The nanoplasma formation process is crucial for understanding x-ray--matter interactions. In a second experiment, the novel twin bunch operating mode for producing two hard x-ray pulses at the LCLS is utilized to investigate nanoplasma dynamics in 70 nm Xe clusters. An initial hard x-ray pump pulse (~15 fs, 1/3 mJ) isochorically heats the nanocluster and a second hard x-ray probe pulse (~15 fs, 2/3 mJ), delayed by up to 80 fs, probes the state of the nanoplasma. In addition to electronic and structural damage, time-resolved signals show an unexpected lattice contraction as the nanoplasma evolves. This contraction is attributed to the strongly enhanced electron mobility, resulting in a drastic change in bond character.

Keywords: Applied Physics.
Advisor: Bucksbaum Philip H. primary advisor. Thesis advisor
Hastings Jerome
Reis David A.
Crystallography of Prussian blue analogues and its effect on electrochemistry [electronic resource]

Rechargeable batteries have revolutionized portable electronics and electric vehicles. Soon, they may also play an instrumental role in the integration of intermittent solar and wind resources by providing cost-effective grid-scale energy. Prussian Blue analogue (PBA) materials have demonstrated exceptional electrochemical properties that make them suitable for a variety of battery applications. However, little is understood about the specific mechanisms that enable these unique properties. In my work, I have demonstrated how the unique crystal structure of PBAs directly affects and enhances their electrochemical properties. In the first part of my dissertation, I showed that a wide variety of divalent and trivalent cations in aqueous solution can be electrochemically inserted and extracted with high speed and reversibility. I used synchrotron X-ray diffraction (XRD) to establish a novel vacancy-mediated pathway for multivalent ion conduction that could be valuable in the future development of multivalent-ion batteries. In the second part of my dissertation, I presented a PBA cathode material (manganese hexacyanomanganate) that exhibits promise as a high-capacity sodium-ion cathode in organic electrolyte. This system possessed the highest sodium-ion capacity (209 mAh/g) ever recorded, and I used synchrotron XRD to understand the structural distortions that enable this unusually high capacity. In the third part of my dissertation, I developed a framework to understand high-capacity PBA cathodes in aqueous systems. Using in situ synchrotron XRD and soft X-ray absorption spectroscopy, I investigated the complex interactions between the electronic structures of metal ions, the crystal structure, and electrochemical properties in this system. These experiments demonstrated fundamental kinetic limitations associated with electronic structure that may affect the future development of high-capacity PBA electrodes.

Keywords: Materials Science and Engineering.
Advisor: Cui Yi
Chueh William
Salleo Alberto
Cultivating the next generation [electronic resource] : three studies of college access among the children of immigrants

Ensuring smooth transitions to college may be difficult for the children of immigrants since their families are likely unfamiliar with the U.S. system of higher education, which is horizontally stratified and requires a number of steps before admission. Bridging social science literature on immigrant assimilation, cultural, social, and human capital, and college choice, I study the pathway to college among immigrant youth, focusing on heterogeneity by generation and legal status and how community and state contexts moderate educational outcomes. In the first paper, I explore inequalities in college knowledge using data from the High School Longitudinal Study of 2009. Specifically, I examine whether 11th graders can accurately estimate tuition and fees at two- and four-year institutions and the expected earnings of various levels of educational attainment. The second paper builds on the first by testing for heterogeneous treatment effects of social interactions in high school using the Education Longitudinal Study of 2002. If there are differences in college knowledge, it is possible that discussing college with teachers, counselors, or college representatives has disproportionate impacts for the children of immigrants. Since 2001, 27 states have passed policies that limit or facilitate college access for undocumented students. Some states have banned them from receiving in-state resident tuition, while others allow it and provide financial aid. The final paper uses survey data from the Current Population Survey and administrative data from California and Texas to determine whether these policy regimes affect college choice and preparation for likely-undocumented Mexican and Hispanic youth. The findings from this dissertation may prove useful to practitioners and policymakers interested in improving the knowledge acquisition, academic preparation, and enrollment decisions of the children of immigrants, a group comprising nearly a quarter of schoolchildren today.

Keywords: Education.
Advisor: Antonio Anthony Lising
Bettinger Eric advisor. Thesis advisor
Jackson Michelle R. (Michelle Renee)
Jiménez Tomás R. (Tomás Roberto)
Cultivating Upstanding Democratic Citizens in the English Classroom: Reader-Response and Teaching the Conflicts Pedagogies

In Stealth Democracy, Elizabeth Theiss-Morse and John R. Hibbing demonstrate that the majority of American citizens are unable to properly engage in conflict because they do not take the perspective of others seriously. Louise Rosenblatt’s vision for the English classroom in Literature as Exploration seeks to address these democratic problems, arguing that students must develop (1) critical thinking skills, where students can reflect on their own positions, and (2) a robust moral imagination, where students can imagine the perspective of someone different from them. This thesis examines and assesses two pedagogical candidates for fulfilling that Rosenblatt’s vision. The first is a variation of “reader-response theory” that aims to address the criticisms against traditional reader-response for being too self-focused and atheoretical. The second is Gerald Graff’s “teaching the conflicts,” which aims to prepare students for conflict by exposing students to conflicts surrounding literature and having students read opposing critical essays about a text. To conduct this study, I taught two 9th Literature classes for four weeks during a summer program, and I taught one class (n = 12) using a critical and multicultural variation of reader-response, and the other (n = 14) using teaching the conflicts. In analyzing the classroom discourse, I found traces of Rosenblatt’s vision fulfilled. While students in reader-response did less well with textual engagement than teaching the conflicts, it did better than its critics claim and facilitated impressive and meaningful personal discussions among students. Students in teaching the conflicts had fewer opportunities for personal engagement than reader-response, but they excelled in cultivating rigorous textual discussion and cultivating critical thinking skills. Both pedagogies are also educationally worthwhile insofar as they facilitate impressive student-to-student discussion.

Keywords: English Education
Literature
moral imagination
Graduate School of Education
high school English
Breakthrough
Louise Rosenblatt
dialogic
student uptake
student discussion
multicultural literature
democracy
textual engagement
teaching the lenses
education
teaching the conflicts
reader-response
Thesis
Advisor: Willinsky John
Levine Sarah
Data driven and uncertainty aware physical modeling [electronic resource]

As computing capabilities grow and the amount of experimental and numerical data increases, computational strategies can be designed to automatically test and assess different modeling assumptions. We introduce a general data-driven statistical framework that bridges the gap between (numerical or laboratory) experimentation, physical modeling and uncertainty quantification. The framework enables the study of uncertainties and bias in physical models estimated from data. We differentiate between two types of modeling uncertainties and bias, the first one due to physical errors in the models and the second one due to noise introduced by the data-acquisition process. We also present different procedures to build models under different noise assumptions and propose a metric to quantify the quality of the data-driven estimations. The framework is tested in the context of combustion science and chemical kinetics and it is driven by empirical data and simple chemistry models. Why reaction rates? A combination of a rigorous application of the statistical framework as well as recently measured kinetic rates data will allow us to propose new modeling strategies for chemical reaction rates, their associated uncertainties, and how these uncertainties propagate into relevant combustion problems. This thesis also shows that the current state of the art of reporting kinetic uncertainties relevant for predictive problems in combustion sciences is incomplete and only focuses on describing the experimental variability. We propose a technique to report uncertainties in a useful manner for scientists interested in studying the predictive capabilities of their numerical simulations where chemical reaction rates are input parameters. Applications include hydrogen chemistry, explosion limits and initial mixture compositions uncertainties in gaseous mixtures. To represent as closely as possible actual experiments in our models, we will review the process of inferring reaction rates from shock tubes devices. Shock tubes are one of the most popular devices used to measure kinetic rates. We will closely examine the uncertainties of measurements inside a shock tube: 1- due to the presence of non-ideal phenomena in the real device (departures from the ideal operation sequence), 2- incomplete knowledge (unknown parameters needed to model the operation of shock tubes) and 3- sensor uncertainties. This framework can be extended to complex predictive problems relevant to turbulence, turbulent combustion and safety related applications (e.g. nuclear waste treatment, detonations etc.) - and to more complicated reaction rates and larger chemical mechanisms when both raw experimental signals and processed reaction rates become more accessible.

Keywords: Mechanical Engineering.
Advisor: Iaccarino Gianluca primary advisor. Thesis advisor
Alonso Juan José
Ihme Matthias
Data-driven cooperative control for wind farm power maximization [electronic resource]

Among the various renewable energy sources, wind power has proven effective for large-scale energy production. To increase wind power production, it is essential not only to increase the number of wind farms but also to operate them efficiently. Conventionally, for a given wind condition, each individual wind turbine maximizes its own power production without taking into consideration the conditions of other wind turbines. Under this greedy control strategy, the wake formed by the upstream wind turbine, resulting in reduced wind speed and increased turbulence intensity inside the wake, would affect and lower the power production of downstream wind turbines. This thesis investigates a cooperative wind farm control approach to optimally coordinate the control actions (i.e., the operational conditions) of the wind turbines. The optimally coordinated control actions minimize the wake interference among the wind turbines and would therefore increase the total wind farm power production. To determine the optimum coordinated control actions, two methods are discussed in this thesis. First, the optimum coordinated control actions for wind turbines are determined using an analytical approach by employing mathematical optimization. In this approach, the total wind farm power is expressed as a function of the control actions of all the wind turbines. The wind farm power function is then maximized using sequential quadratic programming to determine the optimum coordinated control actions for the wind turbines. The effectiveness of the cooperative control strategy is studied using an example wind farm site and available wind data. For the second approach, the optimum coordinated control actions of the wind turbines are derived using the input (control actions of wind turbines) and output (wind farm power) data of a target wind farm. For real-time, data-driven wind farm control, an optimization algorithm should be able to improve target wind farm power production by executing as few trial actions as possible using the wind farm power monitoring data. To achieve this goal, a Bayesian Ascent (BA) algorithm is developed by incorporating into the Bayesian Optimization framework a trust region strategy that regulates the search domain. Numerical simulations using the wind farm power function show that the BA algorithm can be as effective as the analytical approach. Wind tunnel experiments with scaled wind turbines are conducted to further demonstrate the effectiveness of the data-driven BA algorithm for real-time control. Experimental results show that the BA algorithm can achieve a monotonic increase in the total wind farm power production using a small number of trial actions and demonstrate the potential of the BA algorithm for the real-time wind farm control problem.

Keywords: Civil and Environmental Engineering.
Advisor: Law K. H. (Kincho H.) primary advisor. Thesis advisor
Baker Jack W. advisor. Thesis advisor
Murray Walter advisor. Thesis advisor