VictorJuiz/thesis huggingface dataset:
Fast and accurate PET image reconstruction on parallel architectures [electronic resource]
Keywords: Electrical Engineering.

Positron Emission Tomography (PET) has become an invaluable modality for in vivo imaging of molecular signatures of disease. The reconstruction algorithm for PET and the resulting image quality, however, have been limited by the large scale nature of the inverse problem, prohibiting sophisticated statistical algorithms from being used in practice. This work addresses the challenges in PET image reconstruction using state-of-the-art techniques in parallel computing, computer graphics, image processing, and convex optimization. More specifically, we reformulate the image reconstruction algorithm so that it can run efficiently on the massively parallel architecture of the Graphics Processing Unit (GPU). Memory access patterns and execution controls are optimized to maximize device resource utilization. Furthermore, strategies for extending the parallel processing to a cluster of GPUs is developed, taking the inter-node communication overhead into consideration. Finally, the drastic reduction of the computational cost enables practical applications of three methods for image quality and accuracy improvement, including using Point Spread Function (PSF) for resolution modeling, utilizing Compton scattered events in the detectors, and combining multiple reconstructions to achieve higher Signal-to-Noise Ratio (SNR) in motion correction tasks. Experiments show that the proposed methods are able to improve image quality and accuracy while reducing execution time. Part of the work has been integrated into the next generation Philips Time-of-Flight (ToF) PET systems.
Fear and loathing in imperial Japan [electronic resource] : the cultures of Korean peril, 1919-1923
Keywords: East Asian Languages and Cultures.

This dissertation explores the cultures of colonial terror in imperial Japan's metropole. Concomitant to attempts to discursively contain new resistance from colonized Korean subjects after World War I, narratives of conspiracy and terrorism featuring "treacherous Koreans" (futei Senjin) captivated Japan's imperial imagination through state discourse, tabloid journalism, pulp detective novels, travel writing, leftist literature, and popular rumor. This heralded an interwar era of "Korean Peril" in metropolitan print culture, rife with fictional and actual outbreaks of paranoia and violence. By examining the figuration of Korean Peril, this dissertation proposes that, although colonial vocabularies and narrative tropes worked to fix identities and manage the fear and violence attendant to imperial expansion, the process of popular narration frequently drew attention to the ironic gaps and ambivalent contradictions of Japan's approach to colonial empire. Chapter I documents the rise of Korean Peril in Japanese print as it mutated from an official construct of containment and differentiation into a stereotyped discourse of ethnic terror criminalizing all Korean subjects in sensational newspaper reporting. Chapter II considers how Korean Peril was progressively deformed in the process of exploiting the comingled terror and delight evoked by uncanny Korean figures within the unstable genre of Japanese tantei shōsetsu. These generic experiments ended with ambivalent and even unintentionally subversive twists. Chapters III and IV turn to critique and counter-narration of the discursive demonization of Korean rebels, in order to chart the new spaces that both Japanese and Korean writers used to debate and re-signify the terminology of colonial identity and resistance. In the realm of literary counter-discourse, anti-travelogues by the leftist writer Nakanishi Inosuke tread a fine line between complicity and subversion as they parodied both the colonizer's fear of the colonized and the genres of Korean Peril. Finally, Chapter V juxtaposes narratives and images that aimed to ironically reconstruct the 1923 post-earthquake "Korean Panic, " an explosion of communal violence that led to the murders of thousands of Korean residents of Japan, by treating the farcical trope of mistaken identity as a form of national self-critique.
Federal R&D: Analyzing the Shift From Basic and Applied Research Toward Development
Keywords:  Department of Economics
Stanford Department of Economics
United States
federal research and development spending
private firms
Thesis

United States Federal Government research and development spending has shifted in recent years away from basic and applied research and toward development spending. Development is later in the product creation cycle and typically performed by private firms. A 2008 spike in development grants to private firms meant to combat the recession caused the increase, but the level going to private firms has only continued to rise after the recession ended and during the recovery. This paper examines potential explanations for this sudden and sustained increase. I present the economic theory regarding the positive externalities of research and development spending, and argue that basic research provides the largest spillover benefit externalities and is the most under selected in the private market equilibrium. Therefore, economic theory suggests that government focus a greater portion of its spending on basic research, and reverse the recent trend of increasing development grants to the private sector. Spillover benefits of development research have been largely internalized by patent policy that provides monopoly power to firms with innovative products, but intellectual property rights cannot internalize the larger and more powerful basic research externalities because basic research affects many markets. The private sector will never stop funding development research, so I argue that government should allocate more funds to the undervalued basic research fields to help correct the market failure.
Federal Work-Study versus Off-Campus Jobs: Does the type of job matter for post-graduate outcomes?
Keywords:  Department of Economics
Stanford Department of Economics
Work-study
employment
post-graduate outcomes
job quality
Thesis

The Federal Work-Study (FWS) Program was established as part of the Economic Opportunity Act of 1964 to help students find part-time employment to cover the cost of their tuition. Today, the U.S. government allocates nearly $1 billion in FWS funds for students in 3,000 institutions around the country. Even though the FWS program is large, it has not been studied comprehensively because of difficulties finding exogenous variation that explains endogenous work decisions. To overcome this issue, I exploit differences in FWS availability and FWS availability relative to other job opportunities at comparable institutions to instrument for FWS participation and hours worked in school. I find some evidence that FWS participation improves academic and post-graduation outcomes.
Fictions of destruction [electronic resource] : post-1945 narrative and disaster in the collective imaginary
Keywords: Comparative Literature.

In "Fictions of Destruction" I analyze post-1945 narratives that engage with the thematics and aesthetics of mass-scale destruction. The dissertation is based on the thesis that since the explosion of the atomic bombs, a shared imaginary of mass-scale disaster has developed that exhibits a set of concerns particular to the "Nuclear Age, " even while branching out into ecological, scientific and other possible sources of world-destruction. I first redefine the collective imaginary as a product of the oscillating, give-and-take relationship between cultural media and the individual's experience of the world, particularly with the advancement of mass communication technologies. I then give a comparative study of North American narrative fiction, particularly in the U.S., that hone in on issues related to the experience of temporality. These include the trope of the broken road as a move away from the rhetoric of progress and enlightenment and instead toward the impending downfall of modernity; the heightened awareness of risk and how it changes perceptions of futurity; what tropes of disaster fiction such as ephemera, wastelands, and bunkers reveal regarding historicity and possible futures; and how survivor character types illustrate the oscillation between hope and despair through their positions along the spectrum between stasis and action. In addition to its basis in comparative literary studies, this dissertation engages with a variety of disciplines in the humanities such as philosophy, cultural studies, film and media studies and history. Source materials include novels, short stories, graphic narratives, film, television and gaming.
Fine-grain in-memory deduplication for large-scale workloads [electronic resource]
Keywords: Electrical Engineering.

Memory is a large component of computer system cost and current trends indicate this cost is increasing as a fraction of the total. Emerging applications such as in-memory databases, virtual machines, and big-data key-value stores demand more memory relative to compute. Some of these high-memory applications incidentally store many duplicate values in memory: in some cases, duplicates account for over 75% of the total. Recent work on the HICAMP architecture provided a sophisticated hardware mechanism for memory deduplication to implement memory versioning, but without support for current software stacks. This thesis extends work on HICAMP by evaluating a deduplicated memory that is compatible with existing hardware and software. Memory content from actual workloads indicates that deduplicated memory effectively doubles capacity. After understanding the baseline cost-benefit tradeoff in terms of capacity, performance, and energy, this work proposes novel optimizations for machines with deduplicated memory. These optimizations reduce memory traffic and improve performance relative to both the baseline deduplicated memory and, in many cases, relative to the original machine. Energy consumption is reduced because memory devices are reduced with no penalty to performance. Further, deduplication reduces data transfer and improves performance for certain scientific applications. This thesis argues that in-memory deduplication is warranted by its own benefits, which are likely to grow in the future, and that it enables low-cost memory snapshots, as in the HICAMP architecture.
Fishing-driven change in marine parasite assemblages [electronic resource]
Keywords: Biology.

How do anthropogenic environmental impacts affect the abundance, diversity, and species composition of parasite assemblages? Despite the overwhelming ubiquity of parasites -- which constitute at least 40% of species on the planet -- we have only a rudimentary understanding of how parasite abundance and diversity respond to environmental change driven by human activities. My dissertation investigates this question by focusing on marine model systems affected by fishing, one of the most intense and longest-standing impacts on the world's oceans. I assessed how fishing affects parasite abundance, diversity, and taxonomic composition by comparing parasite assemblages of fishes collected from fished and unfished areas. My research suggests that the impacts of fishing on parasites are complex but predictable with an understanding of parasite natural history. Fishing reduced parasite diversity at large spatial scales (i.e., across islands), but had no effect on diversity at smaller spatial scales (i.e., between protected and open-access areas and across a fishing gradient within one island, respectively), where shorter dispersal distances might buffer against local extirpation of rare species. Fishing had negative effects on the abundance of trophically transmitted parasites, particularly cestodes and nematodes, which use as definitive hosts the high trophic-level species most susceptible to fishing impacts. Directly transmitted parasites appeared to track their hosts' response to fishing, increasing in abundance when their host increased in response to fishing pressure. Taken together, the empirical work presented in this dissertation suggests that fishing will have negative effects on parasites, particularly parasites with complex life cycles and those that use exploited hosts. However, the data presented here also emphasize the potential for increases in the abundance of the parasites of hosts that experience compensatory increases due to fishing of their predators or competitors. These results clearly indicate that neither positive nor negative relationships dominate the response of parasite abundance to fishing. Instead -- as has often been documented among free-living species -- there appear to be "winners and losers" among parasites in a changing environment.
Flame synthesis and applications of metal oxide nanowires [electronic resource]
Keywords: Mechanical Engineering.

Herein, two novel methods for the flame synthesis of metal oxide nanowire arrays and related nanomaterials are developed and investigated. Both methods are rapid (micrometer/minute axial growth rate), atmospheric, controllable and scalable, and result in highly pure and crystalline materials. Simultaneously, these methods allow the growth of metal oxide nanowires on diverse, technologically relevant, and often delicate substrates. The first method is flame-heated solid phase diffusion growth, in which a metal substrate is rapidly heated to high temperatures by a flame, and metal oxide nanowires grow by metal diffusion out of the substrate in the hot, oxidative post-flame environment. The second is flame vapor deposition, in which the flame oxidizes and evaporates metals at high temperatures to produce large concentrations of oxide vapors that condense onto cooler substrates in the form of nanowires and other nanostructures. In each method, the chemical composition, growth rate and morphology (shape, packing density and alignment) of the nanostructures can be finely controlled by tuning flame parameters such as the fuel/air ratio and temperature, and substrate parameters such as surface energy and temperature. Moreover, an application of flame synthesized nanowires is demonstrated for the first time. As a result of superior morphology (increased length and packing density), the photoelectrochemical water-splitting performance of flame-synthesized tungsten trioxide nanowires is more than twice that of state of the art tungsten trioxide nanowire photoanodes synthesized by conventional hydrothermal and vapor deposition methods. These flame synthesis methods may enable future generations of technologies based on metal oxide nanowires to be developed and deployed on a large scale.
Forms of sentiment in the 21st century U.S. latina/o novel [electronic resource]
Keywords: English.

My dissertation, Sentimental Forms in the 21st Century U.S. Latina/o Novel, contributes to an emerging body of scholarship on the racialization of feeling within the fields of feminist theory and comparative race and ethnicity studies. Specifically, this project demonstrates how three Latina/o novels, Sandra Cisneros' Caramelo (2002), Salvador Plascencia's The People of Paper (2005), and Junot Díaz The Brief Wondrous Life of Oscar Wao (2007), self-consciously depict the sentiments of first and second generation Latino protagonists. This dissertation argues that these contemporary Latino sentiments are articulated through new character types--acculturated Latinos who form their own sense of Latino identity for the New Millennium while also caring about the political history and fate of immigrants from Latin America. My analysis identifies three historically-aware types: Sandra Cisneros's "pragmatic Chicana, " Salvador Plascencia's "the Melancholic Mexican American, " and Junot Díaz's "Sentimental GhettoNerd." Instead of feeling sympathy and empathy--two emotions associated with the 18th and 19th century sentimental novel that prompts the readers to either "feel for" or "feel with" the less privileged-- these Latino character types emote pragmatism, wistful whimsy, and self-compassion, challenging a traditional model of sentimentality where "identifying with" is a precursor to caring about the pain, struggles and wishes of others. Additionally, these acculturated Latino character types also serve as a model for ethically reading the emotional struggles of the immigrant generation. Overall, this project furthers conversations about the contemporary Latina/o novel, cultural representations of gender and race and how we make sense of the intimate manifestations of history that we deal with on a day-to-day basis.
A framework for rate-independent crystal plasticity in the finite deformation range [electronic resource]
Keywords: Civil and Environmental Engineering.

In this study we present a framework for the stress-strain analysis of polycrystalline materials subjected to quasistatic and isothermal loading conditions. We focus on rate-independent crystal plasticity as the primary micro-mechanism in the plastic deformation of crystalline aggregates. This deformation mechanism is modeled by a nonlinear stress-strain relationship and multiple linearly dependent yield constraints. Convergence problems induced by linear dependency of constraints is one of the challenges in modeling rate-independent crystal plasticity. Failure to converge at a single crystal level can cause numerical stability problems when modeling larger scales such as boundary value problems. In this work we first build a stress point model based on the `ultimate' algorithm in the infinitesimal deformation range. Since this algorithm solves the stress-strain response analytically, the model is unconditionally convergent. Numerical examples are presented to demonstrate the numerical stability of the algorithm and the significance of considering crystal microstructure in modeling the plastic deformation of single crystals. To investigate the overall elasto-plastic behavior of crystalline solids at scales larger than a single crystal, the stress point model at the infinitesimal deformation range is implemented in a nonlinear finite element code. Several boundary value problems are presented to demonstrate the numerical stability of the finite element model and also the effect of considering crystal microstructure on predicting the macro-scale elasto-plastic behavior of crystalline solids. We next formulate crystal plasticity in the finite deformation range. This formulation, which is based on the theory of distribution and strong discontinuity concepts, considers both material and geometric nonlinearity in the plastic deformation of crystals. We propose exact and approximate stress point algorithms to solve the presented framework. To find the set of linearly independent slip systems, we follow the same idea as the `ultimate' algorithm. The presented numerical examples demonstrate that the simplified approximate algorithm is accurate. The examples also indicate the significant impact of geometric nonlinearity on the stress-strain response of single crystals. We derive a framework to analyze the onset and configuration of localization in crystalline solids at infinitesimal and finite deformation ranges. The presented examples demonstrate that geometric nonlinearity has a significant impact on the localization analyses of crystalline solids.
François Couperin's harpsichord music and the Parisian public sphere [electronic resource]
Keywords: Music.

This study salvages François Couperin's eighteenth-century reception from 78 manuscripts containing copies, transcriptions, and altered versions of his harpsichord music. These sources reveal that Couperin's audience knew and appreciated him mainly as a composer of light, charming pieces that spread haphazardly across the public music circuit. This contrasts surprisingly with his reception today, which prizes his richly textured pieces and sophisticated dances instead. The dissertation is organized in four sections supplemented by an extensive inventory of the manuscript sources. The introductory chapter accounts for the disparity between our Couperin and theirs by chronicling Couperin's legacy, focusing primarily on his place in J. S. Bach's first hundred years of posthumous reception and in Debussy's defense of the French Baroque. The second chapter establishes the group of Couperin's pieces that circulated as part of the brunette tradition of popular tunes in his time. It also addresses the thorny issue of dates for Couperin's music and presents previously unknown pieces attributable to the composer. The third chapter contains three case studies that illustrate contrasting conceptions of work identity in the public production and reception of Couperin's music. Here I argue that the dissemination of his popular pieces vividly illustrates a kind of socially configured work concept that Reinhard Strohm claims was operative before the era of the Beethovenian opus. The closing chapter then explores the plurality of social and musical ends that Couperin's music appears to have met in eighteenth-century Europe. Jürgen Habermas's claims about the origins of the public sphere are shown to provide a working framework for the various purposes that steered Couperin's musical efforts.
Frictions in repo markets [electronic resource]
Keywords: Business.

In the first chapter I develop a model of repo lending where the main source of asymmetric information between counterparties is the borrower's initial asset holdings. Borrowers finance a risky asset by taking a repo loan from a monopolist lender, who uses the haircut to infer how well capitalized the borrower may be. Losses stem from the costly liquidation of collateral in case of default. Profits come from borrowers' ability to dilute existing creditors by accepting a higher haircut on the loan, inducing a wealth transfer to the monopolist lender. In the symmetric information case, the lender maximizes the wealth transfer until making the loan absolutely risk free. Under asymmetric information there exist conditions where the optimal contract consists in offering the same lending terms to all borrowers (i.e. pooling equilibrium). In the second chapter, I ask what are the consequences of a potential fire sale stemming from repo's exemption from automatic stay? The chapter shows that repo's exemption from stay alters firms' financing and investment decisions ex-ant by enabling them to purchase defaulted collateral at fire sale prices. Fire sales arise endogenously because of limited capital in the market to purchase collateral posted by defaulted firms, i.e. cash-in-the-market pricing. This effectively creates a premium for holding on to dry powder and concentrates asset ownership with firms who have preferences to hold large risky asset positions and risk default. The premium reduces the initial asset price, potentially inducing more firms to take on risky positions, increasing the fraction of defaulting firms in the economy. When repo is subject to automatic stay, secured lenders do not receive their collateral immediately, eliminating the possibility of a fire sale and ex-ante price distortion.