VictorJuiz/thesis huggingface dataset:
Consensus [electronic resource] : bridging theory and practice

Distributed consensus is fundamental to building fault-tolerant systems. It allows a collection of machines to work as a coherent group that can survive the failures of some of its members. Unfortunately, the most common consensus algorithm, Paxos, is widely regarded as difficult to understand and implement correctly. This dissertation presents a new consensus algorithm called Raft, which was designed for understandability. Raft first elects a server as leader, then concentrates all decision-making onto the leader. These two basic steps are relatively independent and form a better structure than Paxos, whose components are hard to separate. Raft elects a leader using voting and randomized timeouts. The election guarantees that the leader already stores all the information it needs, so data only flows outwards from the leader to other servers. Compared to other leader-based algorithms, this reduces mechanism and simplifies the behavior. Once a leader is elected, it manages a replicated log. Raft leverages a simple invariant on how logs grow to reduce the algorithm's state space and accomplish this task with minimal mechanism. Raft is also more suitable than previous algorithms for real-world implementations. It performs well enough for practical deployments, and it addresses all aspects of building a complete system, including how to manage client interactions, how to change the cluster membership, and how to compact the log when it grows too large. To change the cluster membership, Raft allows adding or removing one server at a time (complex changes can be composed from these basic steps), and the cluster continues servicing requests throughout the change. We believe that Raft is superior to Paxos and other consensus algorithms, both for educational purposes and as a foundation for implementation. Results from a user study demonstrate that Raft is easier for students to learn than Paxos. The algorithm has been formally specified and proven, its leader election algorithm works well in a variety of environments, and its performance is equivalent to Multi-Paxos. Many implementations of Raft are now available, and several companies are deploying Raft.

Advisor: Ousterhout John K. primary advisor. Thesis advisor
Mazières David (David Folkman)
Rosenblum Mendel advisor. Thesis advisor
Constraints on the form and formation of branched channel networks [electronic resource]

This thesis focuses on the form and formation of Branched Channel Networks (BCNs). These networks are among the most striking forms that define the surface of our planet, and are the primary means that transport rock and water from high to low elevations across Earth's surface. As such, they play a fundamental role in shaping the elevation structure of continents, the spatial distribution of vegetation, and the rates and routes by which rocks, nutrients, and water are transported across different terrestrial reservoirs. BCNs also exist in extraterrestrial environments, where, as on Earth, they may encapsulate information regarding the processes and physical conditions under which these environments are shaped. In studying these networks, I pose two main hypotheses: (a) the structure of BCNs is sensitive to the erosional mechanics of the processes that carve them, and (b) a common set of constraints rationalizes the ubiquity of BCNs across disparate physical conditions (e.g., subaerial, submarine, extraterrestrial). First, I evaluate the limitations of the numerical tools with which I test these hypotheses, and show that the flow-routing rules used for the downslope routing of water and sediment over gridded Digital Elevation Models (DEMs) have a statistically significant impact on the form of modeled topography and the spatial distribution of modeled geomorphic processes. Having these limitations in mind, I address the first hypothesis, and show that the structure of BCNs reflects two coupled constraints: (1) the characteristic along-flow channel profile shaped by the channel forming processes, and (2) the fact that two flows initiating at an infinitesimal distance apart on each side of a drainage divide must experience an identical elevation drop between the divide and the junction where these flows once again meet. I then use numerical Landscape Development Model (LDMs) and analysis tools to demonstrate that these constraints impact the plan-view structure of BCNs as well as their temporal evolution, and that the form of these networks is indeed sensitive to the erosional mechanics of the processes that shape them. To address the second hypotheses, I analytically show that a simple dependence between sediment transport rate and the frequency at which geophysical flows traverse landscapes rationalizes the formation of BCNs by a wide variety of process, regardless of the stochasticity or homogeneity in which these processes are generated in time and/or space. Thus, as long as this dependency exists, networks may form by a variety of processes across disparate physical conditions. I then use LDMs based on this analytical framework to demonstrate the conditions for network formation and the relationships between the physical characteristics of flows and the landscape features they form.

Keywords: Geological and Environmental Sciences.
Advisor: Hilley George E. primary advisor. Thesis advisor
Loague Keith M. (Keith Michael)
McHargue Timothy R.
Pollard David D. advisor. Thesis advisor
Constructing novel, genetically encodable tools to study the role of actin in developmental myelination

The insulating myelin sheath formed by oligodendrocytes is crucial for rapid conduction of action potentials. The understanding of how oligodendrocytes wrap this specialized membrane is limited. Actin, a key regulator of cell structure and movement, is hypothesized to play an important role (Bauer et al., 2009). Further investigation of the role of actin in myelination necessitates a cell-specific tool with fine temporal and dose- dependent control. We developed genetically encodable actin-modifying tools (gACTs). Using DNA sequences from endogenous actin-modifying proteins or bacterial toxins allowed us to harness their actin modifying power. At this stage, the constructs allow for temporal control and either dose-dependent or cell-specific control, but ultimately the tool will have all three features. To validate the constructs, we transfected HeLa cells and visualized actin morphology. We found clear actin morphology changes upon transfection for all five constructs with variable effectiveness and cytotoxicity. To provide temporal and dose-dependent control, we fused the destabilization domain (DD) to the constructs (Banaszynski et al., 2006). To provide temporal control and cell specificity, we replaced the strong cytomegalovirus (CMV) promoter with a myelin basic protein (MBP) promoter, conferring expression only in mature stages of oligodendrocytes. In addition to elucidating the role of actin in myelination, gACTs are a useful general cell biology tool to study actin in multicellular processes such as development or diseases such as multiple sclerosis.

Keywords:  Department of Biology
Biology
Neurobiology
Cell Biology
Thesis
Advisor: Zuchero J. Bradley
McConnell Susan K.
Barres Ben
Contemporary Women in Romantic Contexts: Time-travel Period Dramas as Didactic Cultural Productions

Time-travel period dramas, as defined by much of the popular discourse, refer to a kind of costume drama that entails a modern character traveling into the past and taking up a dramatic journey of both romance and personal growth. In this thesis, I study Chinese and Western time-travel period dramas from a feminist perspective. In chapter 1, I discuss the theme of escape as central to time-travel period dramas. Escape functions to criticize women’s conditions in the present and offer a way to leave behind the unsatisfying lifestyles led by the female protagonists. Escape also works as exile, at least in Palace, a compulsory means to punish and educate. This is because it also presents an opportunity for these protagonists to undergo a journey that promises the resolution of those problems with which they struggle at the beginning of the show. In chapter 1, I hope to set up the didactic nature of time-travel period dramas by virtue of its promise to present “solutions” at the end of the shows. In chapter 2, I will observe what defines feminine success in each of the shows. To do this, I will first observe the competitive female homosocial space in Palace and argue why it creates a kind of feminine success that require “beating” other women. This conclusion is drawn with comparison to the cooperative and friendly female homosocial space in Lost in Austen, where the protagonist’s path to happiness is not mutually exclusive with that of the other female characters. Ultimately, I hope to show that an important mode of feminine success in Palace has to do with the manipulation of men, whereas feminine success in Lost in Austen revolves around internal struggles of self-understanding. In chapter 3, these analyses culminate in an examination of the endings of the show, which present the dilemma of staying or leaving the ideal mate/ the past. This is where I will account for most of the tension in study “feminism” across cultures and societies by diving into a deeper exploration of different strategies of interpreting a text. With regard to the Western text, Lost in Austen, I believe that its solution to women’s problems in modern society take on a radical postfeminist message, preaching the freedom of choice without moral, social historical qualifications. In turn, I will argue that the ending of Palace presents a kind of socially subversive narrative by breaking out of the Chinese post-Revolutionary, liberation narrative and confronting the continuity of women’s oppression.

Keywords:  Program in Feminist
Time travel
period drama
feminist studies
Chinese women
contemporary Chinese women's issues
female homosociality
women and television
Chinese television
female success
Palace
Lost in Austen
Janeites
Thesis
Advisor: Sohn Stephen Hong
Contributions to reducing greenhouse gas emissions using computationally evolved lens designs and organic electronics [electronic resource]

The need for reducing greenhouse gas emissions and generating energy from renewable sources is more crucial now than ever before. This has now become imperative because the planet is on the verge of a tipping point with regards to the effects of greenhouse gases on the average temperature of the earth. The work described in this thesis is divided into two parts. The first facilitates the adoption of more renewable energy generation methods, specifically concentrated photovoltaics, in which nonimaging lenses for solar concentration are used. Genetic algorithms will be utilized as a way of designing and evolving such novel shaped lenses with a high half acceptance angle. Two main categories of lenses will be highlighted; the first with a uniform material composition and the second with a gradient refractive index along one and both axes of the lens. The details of the genetic algorithm and operators developed and designed for this purpose will also be discussed. In the second part of the thesis, the emphasis is on creating thin film organic based electronics. These organic electronics are also lightweight, flexible and can be stretched to cover large surface areas. Many applications benefit from thin film embedded electronics such as carbon fiber composite structures. This new kind of smart electronics integrated within composite materials can help in significantly slashing the emissions of greenhouse gases in the transportation sector. This is especially the case in high emissions transport vehicles such as air planes. Light weight, low emissions aircraft that are also safe because of the redundant smart electronics within their design make them more adoptable.

Keywords: Electrical Engineering.
Advisor: Howe Roger Thomas primary advisor. Thesis advisor
Chang Fu-Kuo advisor. Thesis advisor
Solgaard Olav advisor. Thesis advisor
Controlling T cell activation through manipulation of cytoskeletal balance [electronic resource]

T cells must remain sensitive enough to respond to even a single low-affinity peptide presented on an antigen presenting cell while maintaining an activation threshold high enough to prevent spurious activation. Effector and memory T cells have a significantly lower activation threshold than naive T cells, enabling the former to rapidly mount a recall response and clear the nascent infection. While many differences in protein expression and localization between effector, memory, and naive T cells have been discovered, the cellular mechanisms underlying the variable activation threshold are largely unknown. Chapter 2 examines the effects of local stimulation on T cell activation and cytoskeletal regulation. I delivered local signals to naive and effector T cells using an atomic force microscope to measure the generation of force by T cells and the mechanical properties of their cortical cytoskeleton. I found that effector T cells are mechanically soft (reduced elastic modulus) compared to naive cells and that cells contacted with an anti-CD3--coated cantilever have slower stress relaxation kinetics. The latter result suggests active rearrangements of the cortical cytoskeleton. I discovered that effector T cells flux more calcium than naive T cells, but the timing and tempo of calcium flux do not differ. T cells push and pull in response to this local stimulation and produce oscillatory forces with 50-100s periods. Chapter 3 examines global cytoskeletal regulation in T cells. Cells soften within one hour of activation, requiring actin remodeling. This cytoskeletal softening is a general feature of T cell activation, observable whether the cells are activated with anti-CD3, peptide-pulsed antigen presenting cells, or \emph{in vivo} immunization. Cytoskeletal softening was durable, persisting in lymphoblasts several days after removing TCR stimulation and in memory phenotype T cells, suggesting that the cortical cytoskeleton is a `storage' mechanism controlling the threshold of activation. This softening process occured downstream of CD28 costimulation, particularly requiring Rho kinase (ROCK) to maintain basal cytoskeletal stiffness and PI3K to soften the cytoskeleton. Inhibitors of ROCK made T cells mechanically soft without activation, and those cells had larger lamella and flux more calcium. Overall, this work demonstrates bidirectional regulation of T cell activation and the cortical actin cytoskeleton. A mechanically stiff cortex antagonizes activation of naive T cells, raising the activation threshold. Durable softening of the cytoskeleton in effector and memory T cells thus represents a physical mechanism to `store' the activation state of the cell and reduce the threshold.

Advisor: Butte M. (Manish)
Davis Mark advisor. Thesis advisor
Lewis Richard (Richard Sheridan) advisor. Thesis advisor
Melosh Nicholas A. advisor. Thesis advisor
A convex-programming framework for super-resolution [electronic resource]

This thesis proposes a general framework to extract information from low-resolution data, a crucial challenge in applications ranging from microscopy, astronomy and medical imaging to geophysics, signal processing and spectroscopy. Assume that we only have information about the spectrum of a superposition of point sources in the low-frequency band $[-f, f]$. We show that as long as the sources are separated by 2/f, solving a simple convex program achieves exact recovery, in the sense that the original signal is the unique solution to the optimization problem. This is established by leveraging a novel proof technique which constructs a dual certificate by interpolation. In addition, we describe how to implement the recovery algorithm by solving a finite-dimensional semidefinite program, which locates the support of the signal with infinite precision. The guarantees extend to higher dimensions and other models. They imply, for instance, that we can recover a piecewise-smooth function from bandlimited data by super-resolving the discontinuity points. We also provide an analysis of the stability of our method in the presence of noise. On the one hand, we prove that it is possible to extrapolate the spectrum of the original signal up to a frequency F > f to obtain an approximation error between the higher-resolution reconstruction and the truth that is proportional to the noise level times the square of the super-resolution factor (SRF) F/f. On the other hand, we derive support-detection guarantees that quantify the precision with which we can determine the location of each individual point source in the signal.

Keywords: Electrical Engineering.
Advisor: Candès Emmanuel J. (Emmanuel Jean) primary advisor. Thesis advisor
Boyd Stephen P. advisor. Thesis advisor
El Gamal Abbas A. advisor. Thesis advisor
Copyright and incentive [electronic resource] : a music industry with Chinese characteristics

Copyright law is widely perceived as the means to promote social welfare by providing necessary incentive for intellectual creation. There however has been little consensus in copyright literature how artists actually respond to copyright incentives: What factors motivate artists to create works? How do artists perceive the usefulness of copyright protection? Would artists continue their artistic careers in a world without copyright law? This dissertation reports the empirical evidence on copyright and incentive based on the industrial statistics and extensive interviews in the music industry in China, a virtual copyright-free environment featuring one of the highest piracy rates in the world and having generated dramatic developments of the music businesses. The qualitative research indicates three seemingly paradoxical phenomena: While merely 17.9% of all the musicians in the sample referred to economic benefits as at least part of their motivations for music creation, 97.4% specifically recognized money as being important and helpful for music creation. While 56.4% of all the musicians alleged that copyright piracy does not affect their creative motivations, 72% agreed that copyright piracy does affect music creation. While 53.8% of all the musicians explicitly admitted that they had little awareness or knowledge about copyright, 92.3% indicated that the current level of copyright protection is insufficient and 71.8% suggested that copyright law should provide strong incentives for music creation. The empirical evidence itself provides compelling explanations for such paradoxes: Even though musicians primarily create music for the music's sake, copyright law could still supply powerful incentive for music production in a way that not only caters to market demand but allows for wider artistic freedom. Copyright piracy that does not necessarily affect musicians' intrinsic motivations could nevertheless affect music creation in terms of the time spent on music creation, the volume of investment in music creation and ultimately the quality of music creation. Most importantly, copyright incentives do not function as a reward that musicians consciously bargain for and chase after but as a mechanism that preserves market conditions for gifted musicians to prosper, including a decent standard of living, sufficient income to cover production costs, and maximum artistic autonomy during the creative process.

Keywords: Law JSD.
Advisor: Goldstein Paul
Friedman Lawrence M. (Lawrence Meir)
Lemley Mark A.
Coral [delta] 18 O records from Palau and Eastern Island [electronic resource] : contributions to the network of Pan-Pacific high-resolution paleoclimate records

Coral-based proxy records are one of the most powerful tools for extending our understanding of interannual to centennial modes associated with El Niño-Southern Oscillation (ENSO) variability. Such records are also crucial for constraining forecasts under various greenhouse gas emission scenarios. In this dissertation I present an examination of records obtained from two study sites: The Republic of Palau (7.5°N 134.5°E) and Easter Island (27°S 109°W). This dissertation is organized into five chapters and an appendix. Chapter 1 is an introduction to paleoclimate, ENSO, and coral-based proxy records. In Chapter 2, I present the analysis of four records from Palau that were sampled from diverse localities within this study region. We take advantage of the multiple instrumental products and previously published results in our evaluation of the Palau coral [delta] 18O ([delta] 18OCRL) signal. Our primary conclusion in Chapter 2 is that Palau [delta] 18OCRL is well suited to capture ENSO, regardless of the coral environmental setting. We also show that Palau [delta] 18OCRL is primarily related to salinity, with temperature exerting a secondary influence. In Chapter 3 we apply our [delta] 18OCRL calibration results from Palau to the pre-instrumental period. Our records exhibit excellent reproducibility over the 20th century, and show strong coherence with other tropical Pacific [delta] 18OCRL records. We identify a 23/24 year cycle which is robust throughout the West Pacific Warm Pool (WPWP) following the end of the Little Ice Age (LIA). The Palau records show a long-term trend indicative of warming and/or freshening. Chapter 4 presents the results of three previously unpublished [delta] 18OCRL records from Easter Island, which resides in a region that is particularly devoid of high-resolution paleoclimate observations. All of the Easter Island corals display complex growth morphology. As a result, we deploy a range of techniques to develop age models. Our chief conclusion is that the Easter Island [delta] 18OCRL records closely follow hemispheric and global scale temperature trends over the 20th century. We also observe unique seasonal trends, which are likely attributable biases in seasonal carbonate precipitation and our age model schemes. Our analyses of the Easter Island [delta] 18OCRL records support the assertion that decadal variability across the Pacific basin originates in the tropics. All of the [delta] 18OCRL records presented in this dissertation represent significant contributions our understanding of Pan-Pacific climate variability over the past two centuries.

Keywords: Environmental Earth System Science.
Advisor: Dunbar Robert
Arrigo Kevin R. advisor. Thesis advisor
Chamberlain C. Page advisor. Thesis advisor
Maher Katharine advisor. Thesis advisor