VictorJuiz/thesis huggingface dataset:
Fine-grain in-memory deduplication for large-scale workloads [electronic resource]

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.

Keywords: Electrical Engineering.
Advisor: Horowitz Mark (Mark Alan) primary advisor. Thesis advisor
Cheriton David R. advisor. Thesis advisor
Hanrahan P. M. (Patrick Matthew) advisor. Thesis advisor
Fishing-driven change in marine parasite assemblages [electronic resource]

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.

Keywords: Biology.
Advisor: Micheli Fiorenza primary advisor. Thesis advisor
Dirzo Rodolfo advisor. Thesis advisor
Kuris Armand
Lafferty Kevin
Palumbi Stephen R. advisor. Thesis advisor
Flame synthesis and applications of metal oxide nanowires [electronic resource]

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.

Keywords: Mechanical Engineering.
Advisor: Zheng Xiaolin
Cappelli Mark A. (Mark Antony) advisor. Thesis advisor
Mitchell Reginald advisor. Thesis advisor
Forms of sentiment in the 21st century U.S. latina/o novel [electronic resource]

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.

Keywords: English.
Advisor: Moya Paula M. L. primary advisor. Thesis advisor
Elam Michele advisor. Thesis advisor
Saldívar Ramón
A framework for rate-independent crystal plasticity in the finite deformation range [electronic resource]

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.

Keywords: Civil and Environmental Engineering.
Advisor: Borja Ronaldo I. (Ronaldo Israel)
Cai Wei
Linder Christian (Engineering professor) advisor. Thesis advisor
François Couperin's harpsichord music and the Parisian public sphere [electronic resource]

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.

Keywords: Music.
Advisor: Berger Karol
Grey Thomas S.
Moroney Davitt advisor. Thesis advisor
Rodin Jesse advisor. Thesis advisor
Frictions in repo markets [electronic resource]

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.

Keywords: Business.
Advisor: Nagel Stefan
Duffie Darrell advisor. Thesis advisor
Zwiebel Jeffrey advisor. Thesis advisor
From intuition and code to score [electronic resource] : modeling musical output

This D.M.A. dissertation consists of a portfolio of four musical works: Areas (for chamber orchestra), Torcal (for great organ), Gotlhar (for chamber ensemble), and Seco (for two pianos and two percussions). These pieces are the compositional application of my research on computational generative models of music material. One substantial idea during the writing of these compositions is that of formalizing the structure and organization of musical events with the aid of programmable algorithms. A common procedure for the composition of these works observes the Sensory Dissonance Curve model proposed by William Sethares. This model establishes a relationship between the spectrum of a sound and a tuning system in which the timbre of the former will appear most consonant (or dissonant otherwise) to a given scale configuration. The reversal process of defining timbral qualities of sounds given arbitrary scale/tuning fields is also possible. 'Dissonance-curve' scales and tunings defined by specific instrumentations (via their spectra), are subsequently mapped to harmonic/inharmonic chord configurations, whose ratio proportions determine the local rhythmic patterns and the durations of the large-scale form of the pieces. To facilitate the translation of the 'sensory dissonance curve' model and its subsequent mappings into music scores with a high level of notational/symbolic expressivity, I have developed Xa-Lan, a computer program written in Common LISP that uses the 'Expressive Notation Package' of PWGL for final output.

Keywords: Music.
Advisor: Ferneyhough Brian
Chafe Chris advisor. Thesis advisor
Sapp Craig Stuart
Ulman Erik
From MIT to Paraguay [electronic resource] : a critical historical and ethnographic analysis of one laptop per child

One Laptop Per Child (OLPC) represents one of the largest experiments in laptop-driven learning currently underway. Since its founding in 2005, OLPC has been promoting their custom-designed green and white "XO" laptops as a solution for learning and economic growth in the developing world. About two and a half million of these laptops are in use -- 85% of them in Latin America -- and the project has inspired other initiatives in both education and low-cost computing. The XO has become a focal point for diverse and sometimes contradictory discourses about children, technology, education, and development, bringing unlikely groups into conversation around this charismatic object. OLPC and the educational philosophy that inspired it, constructionism, both hailing from the MIT Media Lab, frame themselves as a radical break from unchanging educational tradition. I first explore what the laptops developers intended it to do through a reading of literature about the laptop and the features of the laptop itself. I then compare these intentions with what the laptop is actually doing in a small but well-supported project of 9000 laptops in Paraguay, based on six months of ethnographic fieldwork. In the process, I examine the role that a utopian framing plays in evangelizing OLPC and in making the XO laptop a charismatic object on one hand, and limiting its integration into the messy realities of day-to-day use on the other. In closely examining the ideas built into OLPC's laptops and the ways in which children actually use the machines, my research sheds light on the complicated and often contentious debate over the symbolic and actual role of technology in childhood, education, and development.

Keywords: Communication.
Advisor: Turner Fred primary advisor. Thesis advisor
Bailenson Jeremy advisor. Thesis advisor
Luhrmann T. M. (Tanya M.)
Nass Clifford Ivar advisor. Thesis advisor
Willinsky John
Fundamental analysis and equity volatility [electronic resource]

I examine whether financial statement information can predict future realized volatility incremental to the volatility implied by option market prices. Prior research establishes that option-implied volatility is a biased estimator of future realized volatility. I hypothesize that financial statement information, by providing information about economic events correlated with future volatility, is informative in the prediction of future volatility and not fully incorporated in either past volatility or the market's expectation of future volatility. I confirm this empirically and show that the finding is robust to the measurement of option-implied volatility using either the Black-Scholes formula or a model-free approach. I also document abnormal returns to an option-based trading strategy that takes a long (short) position in firms with financial statement information indicative of high (low) future volatility. Additionally, I provide evidence that contradicts a risk-based explanation for the incremental predictive ability of accounting information. Taken together, my results indicate that the market's failure to fully process accounting-based fundamental information explains some of the previously documented bias in implied volatility.

Keywords: Business.
Advisor: Barth Mary E. primary advisor. Thesis advisor
Kasznik Ron advisor. Thesis advisor
Lee Charles M. C. advisor. Thesis advisor
GaAs-based 1550 nm GaInNAsSb lasers [electronic resource]

Low-cost, long-wavelength light sources are indispensable for the widespread deployment of fiber-to-the-home networks. Vertical cavity surface emitting lasers (VCSELs) are ideal for these applications due to their high fiber-coupling efficiency, low power consumption, simple packaging and wafer-scale manufacturability. In particular, VCSELs emitting in the C-band (1530-1565 nm) are highly desirable given that the fiber optical loss is minimal in this wavelength range. High-performance 1550 nm InP-based VCSELs using various distributed Bragg reflector (DBR) technologies have been demonstrated, but these approaches generally require complex and extensive processing, leading to high manufacturing costs. In contrast, GaAs-based VCSELs can be processed in a simple and robust way by exploiting the superior material properties of Al(Ga)As/GaAs DBRs and the oxidation of AlAs layers for electrical and optical confinement. Dilute nitride GaInNAsSb alloys emitting in the 1200-1600 nm wavelength range can be grown coherently on GaAs substrates, enabling the realization of long wavelength GaAs-based lasers. Despite significant challenges in the growth of such highly-mismatched alloys, 1550 nm GaInNAsSb lasers with relatively low threshold current densities have been demonstrated. This dissertation describes recent progress on the development of GaInNAsSb lasers. Optimization of the growth and annealing conditions enabled a four-fold enhancement of the luminescence efficiency of GaInNAsSb quantum wells with GaNAs barriers. In addition, incorporation of GaAsP barriers significantly improved the temperature stability of the lasers. The improved quantum wells enabled the realization of the first electrically-pumped GaInNAsSb VCSELs emitting in the C-band that operate at and above room temperature.

Keywords: Electrical Engineering.
Advisor: Harris J. S. (James Stewart)
Miller D. A. B. advisor. Thesis advisor
Vuckovic Jelena advisor. Thesis advisor
Gas-phase reaction dynamics [electronic resource] : from billiard balls to geometric phase in H + H2

Hydrogen exchange reaction, the simplest chemical transformation, has been studied experimentally by measuring the angular distributions of the H + H2 → H2(v', j') + H reaction products, that were detected with v' and j' state specificity. Although the expected behavior is observed -- wherein the H2 products scatter into a more sideway direction with increasing rotational excitation of the hydrogen product -- we have also uncovered a previously unseen trend, wherein the H2 reaction products scatter into a more backward direction with increasing j', i.e. the opposite behavior to the expected one! In addition, certain rotationally cold products of the H + D2 → HD(v' = 2, j' = 0) + D reaction at a center-of-mass collision energy of 1.25 eV are forward-scattered due to a time-delayed mechanism. Finally, an attempt has been made to measure the theoretically predicted Geometric Phase effects in the H3 system. To this end, a reaction where 'nothing happens' has been studied, namely H + HD → HD(v', j') + H, because the sole Geometric Phase effect is to change the sign in front of the oscillatory term that describes the interference between the experimentally indistinguishable reactive and inelastic scattering pathways. Fine out-of-phase oscillations calculated theoretically have turned out to be beyond the experimental resolution.

Keywords: Chemistry.
Advisor: Zare Richard N. primary advisor. Thesis advisor
Martinez Todd J. (Todd Joseph)
Pecora Robert