VictorJuiz/thesis huggingface dataset:
Habit analysis : using decision analysis to take control of habits

Every person has hundreds and thousands of habits that they rarely think about having. Every time a person exercises a habit, they automatically choose a course of action. Every time that choice is made is an opportunity to apply decision analysis. However, normal decision analysis is too costly to use for all of a person's habits. In this dissertation I look at ways that decision analysis can be applied to a person's habits to ensure they are good ones. If they are not, they must be updated to match an ever-changing environment, new information, and preferences that evolve over time. Expanding decision analysis to include the numerous tiny decisions that are made with habits opens up the opportunity for massive gains in value when each tiny improvement is aggregated over many habits and a lifetime of use.

Keywords: Management Science and Engineering.
Advisor: Howard Ronald A. (Ronald Arthur)
Robinson Burke Edward
Shachter Ross D.
Hacking the retinal code to restore sight to the blind: localizing current spread in the retina

Epiretinal prostheses are designed to restore vision in people blinded by photoreceptor degenerative diseases, by directly activating retinal ganglion cells (RGCs) using an electrode array implanted on the retina. However, in present-day clinical devices, large current spread to distant grounds often results in the activation of many cells. Achieving greater acuity of artificial vision may require the ability to control RGC activity more finely. In this study, the ability to selectively activate individual RGCs using local return stimulation was evaluated. A custom multi-electrode array was used to simultaneously stimulate and record from hundreds of RGCs in isolated primate retina. Stimulation with a single electrode and a distant ground was compared to stimulation in which the ground was provided by neighboring electrodes. Local return stimulation allowed activation of cells near the central electrode while avoiding activation of cells farther away. This made it possible to more reliably activate a target cell without activating a non-target cell. These results suggest that a device that restricts the electric field through local returns could optimize activation of target neurons at cellular resolution, potentially improving the quality of artificial vision.

Keywords:  Department of Biology
Biology
Artificial Retina
Electrophysiology
Retinal Ganglion Cells
Epiretinal Stimulation
Blindness
Thesis
Advisor: Chichilnisky EJ
McConnell Susan
Haptic feedback system design for MR-guided needle intervention [electronic resource]

Advances in imaging are leading to new opportunities for medical diagnosis and treatment, including the possibility to perform procedures such as biopsies while a patient is undergoing imaging. Along with these new opportunities come new challenges. In particular, for patients undergoing magnetic resonance (MR) imaging, the geometry of the MR machine makes it difficult to perform procedures. One solution is to provide robotic or teleoperated equipment that can fit in the remaining space between a patient and the inner walls of the MR bore and manipulate tools such as biopsy needles. A physician stands near the MR machine, viewing live images and controlling the robotic equipment within. However, in this scenario the physician lacks the tactile sensitivity that she would have if manipulating a needle with her own hands. This thesis presents technology to provide haptic feedback to a physician operating a master device that controls a robotic system for MR-guided procedures. The first part of the solution is a new biopsy needle instrumented with optical fibers with Bragg gratings. The needle is equipped with features to enhance its sensitivity to forces applied at the tip of the needle. The optical fibers are unaffected by the intense MR field, and the needle produces no imaging artifacts beyond those of a standard biopsy needle. The second part of the thesis introduces two different types of haptic displays that present the radial and axial forces, respectively, from the instrumented needle. The radial forces provide guidance to users attempting to target small, compliantly-supported objects (e.g. tumors) in tissue. The axial forces provide users with the ability to detect when the tip of the needle has contacted bone or punctured a membrane. In both cases, the displays use materials and actuators that are MR-compatible. Controlled experiments confirm that human subjects can use the information provided by the displays to improve targeting accuracy and to detect membrane contact. An additional experiment shows that force information provided by the needle can reveal changes in tissue texture, for example, when passing through healthy or fibrotic liver tissue.

Keywords: Mechanical Engineering.
Advisor: Cutkosky Mark R. primary advisor. Thesis advisor
Daniel Bruce (Bruce Lewis) advisor. Thesis advisor
Okamura Allison advisor. Thesis advisor
Harry Bertoia and postwar American design culture

This dissertation investigates the confluence of art, design, and corporate interests in the career and oeuvre of Harry Bertoia (1915-1978). Since the Industrial Revolution, modernist art has labored to distinguish itself from design and the associated threat of being dismissed as 'merely' commercial, decorative, or craft. The decades following World War II saw an amplification of this modernist anxiety. Alongside the rise of Abstract Expressionism, a new design culture flourished in postwar America, bolstered by the powerful economic and political interests of big business. Design assumed unprecedented prominence as a central means of relating to increasingly abstract systems and institutions. Bertoia occupied a fraught position in this cultural landscape. In the course of his four-decade-long career, his practice routinely crisscrossed the categories of fine art, design, and craft. His extensive output includes hollowware, jewelry, monotypes, furniture, welded and cast metal sculpture, and sound recordings. This study demonstrates how his work dramatized the competing aims and claims of modernist art and design in the Cold War period.

Keywords: Art and Art History.
Advisor: Lee Pamela M. 
Keller Sean (Architectural historian)
Troy Nancy J. 
Turner Fred
Have abstraction and eat performance too [electronic resource] : optimized heterogeneous computing with parallel patterns

High performance in modern computing platforms requires programs to be parallel, distributed, and run on heterogeneous hardware. However programming such architectures is extremely difficult due to the need to implement the application using multiple programming models and combine them together in ad-hoc ways. High-level programming frameworks based on parallel patterns have recently become a popular solution to raise the level of abstraction and provide implicitly parallel execution on a variety of architectures. Portable performance is often still difficult to achieve however due to the system's inability to optimize programs across data structure abstractions and nested parallelism. In this dissertation, I introduce the Delite Multiloop Language (DMLL), a new intermediate language based on common parallel patterns that captures the necessary semantic knowledge to efficiently target distributed heterogeneous architectures. Combined with a straightforward array-based data structure model, the language semantics naturally capture a set of powerful transformations over nested parallel patterns that restructure computation to enable distribution and optimize for heterogeneous devices. These transformations enable improved single-threaded performance, greater parallel scalability, smaller memory footprints, transparently targeting distributed memory architectures, and automated data movement and distribution. I also present experimental results for a range of applications spanning multiple domains and demonstrate highly efficient execution compared to manually-optimized counterparts in alternative systems.

Keywords: Electrical Engineering.
Advisor: Olukotun Oyekunle Ayinde primary advisor. Thesis advisor
Kozyrakis Christoforos
Ré Christopher advisor. Thesis advisor
Header Bidding and Auctions with Intermediaries

Widespread usage of real-time bidding to sell digital display advertising has ush- ered in new auction formats such as header bidding. Instead of ad exchanges directly auctioning ad slots, header bidding makes multiple ad exchanges compete in a unified auction run by the publisher. We model this “auction on auctions” and analyze the intermediary and bidder incentives to choose between different auction formats. First, we show that when an intermediary does not commit to a pricing rule but has certain restrictions on what it can charge, the optimal strategy for the bidders is the same as that in the first price auction. Second, when there are direct deals, there are also clear incentives for intermediaries to choose a first price auction. Finally, when the bidder can choose between participating with a first price intermediary and a second price intermediary, we give a condition on the private value distribution that induces participation with only the first price intermediary. These findings help explain a recent shift towards first price auctions in the real-time bidding industry.

Keywords: ads
auctions
digital display advertising
header bidding
real-time bidding
Thesis
Advisor: Milgrom Paul
Health Impacts of Non-Functioning Water Points in Uganda

22% of water points in Sub-Saharan Africa are estimated to be non-functional on any given day (Banks 2016). This paper asks whether a non-functioning water point has an effect on the health of the individuals living nearby. I utilize variation in the location, type, and functionality of wells throughout the Republic of Uganda, as recorded in the Water Point Data Exchange (WPDx). Individual-level data from the Ugandan Demographic and Health Surveys (DHS) is employed to examine how differences in exposure to non-functioning water points affect the prevalence of diarrhea, stunting, and mortality for children under the age of 5. This paper finds that increased exposure to a non-functional water point increases the prevalence of caregiver-reported under 5 diarrhea in rural areas. There is no significant effect of either newly constructed improved water points or non-functional water points on stunting or child mortality. I discuss policy recommendations and suggest new areas of research.

Keywords: development economics
development
community health
diarrhea
childhood mortality
sanitation
WASH
Thesis
Advisor: Bhattacharya Jay
Heartbroken : democratic emotions, political subjectivity, and the unravelling of the Weimar Republic, 1918-1933

This dissertation investigates how German intellectuals, activists, and elected officials wrestled with the relationship between emotions and democracy during the years of the Weimar Republic (1918--1933), Germany's tumultuous first democratic experiment. It upends long-held historiographical assumptions about the sober rationality of Weimar republicans, unearthing rather the startling extent to which Germans both imagined and cultivated particularly democratic feelings in the years after the First World War: erotic desire and neighborly love, nostalgia and solidarity and belonging and righteous anger. This dissertation both charts the emergence of this passionate democratic style and tells an unsettling story about how and why it finally vanished. The following dissertation argues that while this renunciation was not inevitable, it is does help to explain how Germany's interwar democratic culture came to be so brittle. In this way, the dissertation offers an alternative explanation for the unravelling of Weimar democracy in the early 1930s. Most broadly, by tracing shifting ideas about democratic emotions and human nature, this dissertation offers European historians as well as scholars of democracy a novel way of approaching the success and failure of modern democratic states.

Keywords: History.
Advisor: Daughton J. P. (James Patrick) 
Sheffer Edith
Baker Keith
Hoffman Stefan-Ludwig 
Press Steven
A heuristic for varying design parametrization applied to a multidisciplinary rotorcraft problem [electronic resource]

At the aircraft conceptual design stage the potential design space is extremely large and the selection of the right set of design variables can be critical to finding a design optimum of practical value. This selection problem is particularly challenging for the human designer when the space not well understood. A means to improve the parametrization automatically as design and optimization proceeds with a heuristic approach to parametrization discovery is described in this dissertation. The heuristic applies important principles of evolutionary theory including: mutation, competition, and selection in searching for a better parametrization. The principles of parsimony in conjunction with variation in mutation probability are shown to to be important in ensuring efficient use of the degrees of freedom in an optimization problem. These prevent the parametrization size from tending toward infinity over successive generations while still finding better objective function values. Starting from simple geometry matching problems, with well defined objectives, and working up to complex multidisciplinary rotorcraft vehicle design problems, the heuristic is shown to have an ability to discover parametrizations which lead to improved objective function values compared to what can be achieved with the initial parametrization. A set of necessary methods are also developed to enable higher-fidelity analysis of rotorcraft designs earlier in the design process, when coupled with the parametrization discovery heuristic.

Keywords: Aeronautics and Astronautics.
Advisor: Alonso Juan José
Iaccarino Gianluca advisor. Thesis advisor
Senesky Debbie advisor. Thesis advisor
Hidden Injuries: The Challenges of Preventing Fatalities in Horse Racing

There is no easy or reliable method to identify microscopic injuries in horses that can lead to catastrophic breakdowns while racing. In an attempt to prevent as many fatalities as possible, at Golden Gate Fields in Albany, California, veterinarians inspect horses before and after every race. But despite best efforts, some horses that pass the medical examination and show no external signs of injury or lameness will still suffer fatal injuries.
Although it is impossible to prevent all fatalities in horse racing, California has lowered the fatality rate in recent years. There have been extensive efforts to ensure that race horses have a high quality of life during and after their racing career.

Keywords:  Department of Communication
horses
horse racing
thoroughbreds
California Horse Racing Board
fetlock
horse injuries
Golden Gate Fields
Thesis
Advisor: Migielicz Geri
High performance cloud computing

Running fast computations at a large scale increasingly stresses task scheduling performance. As CPU performance becomes the performance bottleneck, it is common to optimize CPU performance, further parallelize computations by using more nodes, and split computations into more finely-grained tasks. As a result, a cloud framework running an application on thousands of cores must schedule hundreds of thousands of tasks per second. A framework must be also able to dynamically reschedule tasks in order to achieve high CPU utilization in the presence of an unbalanced load, stragglers, and node failures. Today, systems must choose either high task throughput or dynamic, centralized scheduling: no existing system can provide both. This dissertation proposes a data-centric asynchronous control plane, which schedules hundreds of thousands of tasks per second while retaining a central interface to dynamically reschedule tasks. In this design, a central controller decides how to redistribute work, but workers locally decide between themselves when to redistribute. The controller avoids issuing per-task scheduling decisions by using data placement as the control signal for load distribution. So this design provides a declarative, central, and asynchronous load control mechanism without limiting task throughput. This control plane depends on a new program abstraction, called task recipes, that enables workers to locally schedule tasks and asynchronously migrate data and computation. This dissertation implements the design in a from-scratch in-memory cloud framework called Canary and evaluates its performance on data analytics and machine learning benchmarks. Furthermore, this dissertation examines how applications benefit from the design by using fluid simulation as a case study, and it proposes a new load-balancing algorithm in this context.

Keywords: Electrical Engineering.
Advisor: Levis Philip 
Aiken Alexander 
Rosenblum Mendel
High resolution photovoltaic retinal prosthesis with three-dimensional neural interface [electronic resource]

The number of electronic implants for restoration of various neural functions is rapidly growing. They include such highly successful systems as cochlear implants for restoration of hearing and deep brain stimulators for reducing the symptoms of Parkinson's disease. Retinal degenerative diseases lead to loss of photoreceptors, while neurons in the inner retinal layers are largely preserved. Retinal prostheses seek to restore sight by reintroducing visual information via electrical stimulation of the surviving neurons in the retina. Most retinal prostheses are powered through inductive coils, requiring complex surgery. At Stanford, our group developed a photovoltaic approach to retinal prosthetics, where silicon photodiodes in each pixel of the sub-retinal array convert pulsed near-infrared illumination projected from video goggles into an electric current to stimulate the nearby neurons. This work presents the design and fabrication process of the implantable photovoltaic arrays, and demonstrates their performance in vitro, as well as the results of preclinical testing in vivo. In particular, we have shown that spatial resolution of prosthetic vision with 70 um pixels in rodents is limited by the pixel pitch, and stimulation thresholds are much lower than the ocular safety limits. Based on this success, we developed a new process that enabled fabrication of pixels as small as 40 um in size. To improve proximity between the electrodes and neurons, we developed three-dimensional pillar electrodes, and found their optimal height for integration with the retina during chronic implantation. We also developed a fabrication process for incorporating these pillar electrodes into photovoltaic arrays. During early in vivo experiments, we observed significant degradation of the retinal implants. To prevent this, we developed a process of using a plasma-enhanced chemical vapor deposited SiC films compatible with the rest of the photovoltaic array fabrication. This coating exhibited excellent stability during accelerated aging tests in vitro as well as during chronic implantation in vivo. The final chapter of this thesis provides outlook toward future directions for advancement and testing of this novel retinal prosthetic technology.

Keywords: Electrical Engineering.
Advisor: Harris J. S. (James Stewart)
Kamins Theodore I.
Palanker Daniel advisor. Thesis advisor
High temperature and transient behavior of GaN heterostructure based high electron mobility micro-pressure sensors [electronic resource]

Gallium nitride (GaN) is a wide bandgap semiconductor that is a promising material platform to build sensors and electronics for operation in harsh environments (e.g., Venus). AlGaN/GaN and InAlN/GaN heterostructures are leveraged to build transistors by utilizing a highly conductive sheet of electrons that forms at the interface of these materials, known as a 2-dimensional electron gas (2DEG). A piezoelectric polarization at the interface of GaN and AlGaN or InAlN are partially responsible for the 2DEG, and also enable strain and pressure sensing. The goal of this work was to design, microfabricate and characterize a temperature-tolerant, pressure sensor to support sensing in high temperature environments. This work characterized the pressure response of an InAlN/GaN micro-pressure sensor from 0 to 28.5 psig and the temperature response of solid state and released device up to 550°C. While InAlN/GaN and AlGaN/GaN devices show promise for high temperature pressure sensing, challenges around repeatability also need to be addressed. In order to understand the temperature dependence of the pressure sensitivity and transient device response, electronic traps are characterized in an AlGaN/GaN device between room temperature and 200°C.

Keywords: Mechanical Engineering.
Advisor: Kenny Thomas William primary advisor. Thesis advisor
Senesky Debbie primary advisor. Thesis advisor
Pruitt Beth advisor. Thesis advisor
High-efficiency ultrathin crystalline silicon solar cells

The climate change associated with burning fossil fuels as dominant energy resource has been a significant concern. Solar photovoltaics (PV) is the dominant type of renewable and eco-friendly energy resource to alleviate this problem. Crystalline silicon (c-Si) PV has been the dominant type of solar cell with more than 90% of the global PV market at the end of 2017, because of its low-cost, good stability and well-developed processing technology. To continue reducing the price of solar modules, ultrathin c-Si solar cells have been investigated: they are a feasible pathway to continue "price scaling" by effectively reducing the c-Si material consumption. However, the performance of ultrathin c-Si cells is constrained by two physical limitations: poor light absorption and contact recombination. To achieve the optimal efficiency from ultrathin c-Si cells, the cells must be designed to overcome these limitations. This dissertation provides comprehensive experimental strategies to overcome these two performance limitations of ultrathin c-Si solar cells. The main part of this dissertation concludes with the characterization of the "free-standing", ultrathin c-Si cell integrated with carrier-selective contacts and light trapping structures. These cells show very consistent performance before and after being released from the substrate. These findings show the capability of ultrathin c-Si technology to not only reduce the material cost, but also maintain high efficiency.

Keywords: Materials Science and Engineering.
Advisor: Harris J. S. (James Stewart)
McIntyre Paul Cameron 
Kamins Theodore I.
High-energy gamma-ray observations of solar flares with the Fermi large area telescope

Solar flares are the most energetic events in our Solar System. They consist of sudden energy release from reconfiguration of magnetic fields, leading to acceleration of particles to relativistic energies. The Fermi Large Area Telescope (LAT) gamma-ray observations of the Sun present a unique opportunity to explore the mechanisms of high-energy emission as well as particle acceleration and transport in solar flares. I will present the results of the first 9 years of observations of the active Sun by the Fermi-LAT, which represents the largest sample to date of detected solar flares with emission greater than 30 MeV. Some of the new detections confirm the standard models for solar flares based on observations from past missions in the 1980s and 90s, but new behaviors have also been identified: detections of delayed gamma-ray emission lasting up to 20 hours and the first detection of gamma-ray emission above 100 MeV from three solar flares originating from behind the visible part of the Sun. Considering all of the 46 flares detected by the Fermi-LAT, I will describe the characteristics of the first gamma-ray solar flare catalog covering Solar Cycle 24, exploring trends and correlations with the most relevant solar events: X-ray emission, coronal mass ejections, and direct detection of solar energetic particles.

Keywords: Physics.
Advisor: Michelson Peter F. 
Omodei Nicola
Petrosian Vahe 
Scherrer Philip H.