VictorJuiz/thesis huggingface dataset:
A Warping Framework for Wide-Angle Imaging and Perspective Manipulation

Nearly all photographs are created with lenses that approximate an ideal pinhole camera---that is, a perspective projection. This projection has proven useful not only for creating realistic depictions, but also for its expressive flexibility. Beginning in the Renaissance, the notion of perspective gave artists a systematic way to represent three-dimensional space on a two-dimensional canvas. However, unlike photographers---who have traditionally been tied to the optical designs of their cameras---other artists have been able modify the perspective projection relatively easily. They can locally adapt the projection in places where it makes objects look distorted, and they can more easily control the projection via two-dimensional image space features./nIn this thesis we describe two projects based on image warping that give photographers some of the same control over spatial layout that painters have always had. The first is a technique to minimize distortion in a wide-angle image. Any projection of a 3D scene onto a plane unavoidably results in distortion; current methods either bend straight lines in the scene or locally distort the shapes of scene objects. Here, we present a method that minimizes this distortion by adapting the projection to content in the scene, such as salient scene regions and lines, in order to preserve their shapes. Our optimization technique computes a spatially-varying projection that respects user-specified constraints while minimizing a set of energy terms that measure wide-angle image distortion. We demonstrate the effectiveness of our approach by showing results on a variety of wide-angle photographs, as well as comparisons to standard projections./nInspired by the way painters sketch vanishing points and lines to guide the construction of perspective images, the second project is a tool that gives users the ability to manipulate perspective in photographs using similar controls. This approach computes a 2D warp guided by constraints based on projective geometry. A user annotates an image by marking a number of image space constraints, including planar regions of the scene, straight lines, and associated vanishing points. The user can then use these constraints as handles to control the warp. Our system optimizes the warp such that straight lines remain straight, planar regions transform according to a homography, and the entire mapping is as shape-preserving as possible. We demonstrate how this approach can be used to produce a variety of effects, such as changing the perspective composition of a scene, exploring artistic perspectives not realizable with a camera, and matching perspectives of objects from different images so that they appear consistent for compositing./nWhile the results of these techniques are not true perspective projections of a scene, they resemble perspective images and better satisfy a photographer's artistic vision.

Advisor: Agrawala, Maneesh
For SubContinental Political Theory: On the Non-Brahmin Self-Respect Critique of Gandhian Self-Rule

This dissertation documents and deploys the Non-Brahmin self-respect critique of Gandhian self-rule as a way to reconsider the once nascent but now growing field of comparative political theory. There are two audiences for this critique./nThe first audience is composed of those interested in the field of comparative political theory. Many of this field's inaugural and subsequent methodological articulations have been wed to the figure of Gandhi and his demand for swaraj, suggesting that a self-ruling self is central to what it means to do political theory outside the Euro-Atlantic. Yet the Non-Brahmin members of the Self-Respect Movement (Cuya-Mariyātai Iyakkam) from the 1920s-1940s in Tamil-speaking South India were concerned that a priority placed on Gandhian swaraj would entrench, rather than erase, relations of hierarchy they called Brahminism. For Non-Brahmins, any meaningful self-rule would require a prior self, a self of self-respect, forged not in the opposition between colonial dependence and national independence but world-wide interdependence./nThe second audience is composed of those interested in the history and politics of 20th century Tamil-speaking South India. EV Ramasami Naicker [EVR or "Periyar"], the founder of the Self-Respect Movement, persists as a central figure to the political parties of contemporary Tamil Nadu and remains associated with an ethno-linguistic separatism focused on Tamil language and Dravidian identity. This persistence, however, fails to grapple sufficiently with the internationalism behind his self-respect critique of self-rule and his subsequent investments in the wider world./nFocusing on Tamil archival sources related to the Self-Respect Movement as a way to appreciate the role of Tamil in the world and the world in Tamil, I suggest that the basic distinctions between regions or traditions presumed in demands for or of comparative political theory break down. Instead of framings involving encounter, I argue for a shared tradition of political theory forged across a long distance relationship between European Continent and Indian Subcontinent. This shared tradition involves mariyātai and Mission, dharma and Marx, Aryan and Pariah, Jew and Untouchable, Nazi and Congress, Palestine and Pakistan, secularism and love, householder and ascetic, Islam and equality, and innumerable other instances of embrace and refusal, translation and conversion, in order to challenge Brahminical forces of unfreedom in the world. I call this tradition "SubContinental Political Theory."

Advisor: Brown, Wendy
Molecular Simulations of Lipid Bilayers and Membrane Helices Interactions

In this work we use mesoscopic simulation to investigate the short and medium range interaction of transmembrane helices. First, we develop a coarse-grained model of a generic transmembrane α-helix. We use the geometry constraints of an α-helix, along with a set/nof homogeneous hydrophobic beads. We discuss the reasoning behind this modeling and why various other plausible models have failed in describing the short-range interactions of transmembrane helices./nWe then show the effect of hydrophobic mismatch on these model helices. The tilt angle of a single helix is affected by its hydrophobic mismatch with the surrounding bilayer. We show that the hydrophobic mismatch, via its effect on the tilt angle, has a crucial effect on the cross angle of two packed transmembrane helices as well./nWe further show the effect of hydrophobic mismatch on the potential of mean force between the helices as well as on the thickness and tilt angle of the lipids surrounding the helices. We introduce a class of especially long helices, termed super-positive mismatched/nhelices, to which the response of the lipids differs and discuss the origin of this behavior./nThese coarse-grained simulations are performed using the Dissipative Particle Dynamics (DPD) scheme Performing large time and length scale simulations using this scheme is highly CPU-time consuming. To enhance our simulation capabilities we develop a novel, massively parallel simulation algorithm. We introduce this algorithm and the original concepts we developed for parallelizing the DPD scheme. We show that this novel approach provides/nup to 30 times speed up on a Graphical Processing Unit (GPU) over the non-parallel CPU version./nFinally, we use our parallel algorithm to perform simulation on a large time and length scale system. We investigate the effect of Cholesterol on the bending rigidity of lipid bilayers and show the effect of a phase transition on the bending modulus. Extracting the bending modulus from simulation requires a large system that enables long-range height fluctuations. Using a fast, parallel simulation algorithm for such a task is therefore crucial.

Advisor: Smit, Berend
An Integrated Framework for Planning and Control of Semi-Autonomous Vehicles

This thesis presents the design of a novel active/nsafety system preventing unintended roadway departures. The/nproposed framework unifies threat assessment, stability, and/ncontrol of passenger vehicles into a single combined optimization/nproblem. A nonlinear Model Predictive Control (NMPC) problem/nis formulated where the nonlinear vehicle dynamics, in closed-/nloop with a driver model, is used to optimize the steering and/nbraking actions needed to keep the driver safe. A model of the/ndriver's nominal behavior is estimated based on his observed/nbehavior. The driver commands the vehicle while the safety/nsystem corrects the driver's steering and braking action in case/nthere's a risk that the vehicle will unintentionally depart the/nroad. The resulting predictive controller is always active and/nmode switching is not necessary. We show simulation results/ndetailing the behavior of the proposed controller as well as/nexperimental results obtained by implementing the proposed/nframework on embedded hardware in a passenger vehicle. The/nresults demonstrate the capability of the proposed controller to/ndetect and avoid roadway departures while avoiding unnecessary/ninterventions.

Advisor: Hedrick, Karl
Borrelli, Francesco
New finite elements with embedded strong discontinuities to model failure of three-dimensional continua

This work addresses the developments of new finite elements with embedded strong discontinuities for the modeling of three-dimensional solids at failure in the infinitesimal small-strain or finite deformation regimes./nCracks and shear bands involving the localized dissipative mechanism in a relatively narrow zone provide typical examples to be modeled by this strong discontinuity approach. The narrowness of such a localized region compared to the size of the overall mechanical problem then reveals the multi-scale character of the physical phenomena, thus allowing the given problem to be split into the typical global continua involving only smooth displacement fields and a small-scale problem to represent localized solutions./nThe direct consequence of the multi-scale approach is on the element-based enhancement for the associated singular field in the discrete setting,/nleading to the very same number of global degrees of freedom and mesh connectivity as the original problem without the discontinuity. This procedure is then achieved by the direct identification of the discrete kinematics associated to the sought separation modes of the individual finite elements. In particular, we focus on the direct enhancement of infinitesimal strains (for the infinitesimal case) or deformation gradients (for the finite deformation case) rather than attempting to find the associated displacement field in terms of discontinuous shape functions, also allowing the proposed formulations to be more generally applicable to the strain-based high performance finite elements./nGiven the complex kinematics arising from discontinuities in three dimensions, the new finite elements consider full linear interpolations of the displacement jumps on both the normal and tangential components to the discontinuities in the interiors of the respective finite elements. The incorporation of the high order separation modes then allows a complete vanishing of stress locking, namely, over-stiff responses of the approximated solutions due to the poor resolutions of discrete kinematics associated to the discontinuities. A total of nine enhanced parameters for each element are required to represent the linear displacement jumps, but being condensed out at the element level in virtue of the proposed discrete multi-scale framework./nTo illustrate the improved performance of the new three-dimensional finite elements with embedded strong discontinuities, several representative numerical examples such as a series of basic single element tests and a set of benchmark problems are implemented. The elements involving only piecewise constant displacement jumps are also considered there for comparison purposes, showing by design the overall improvement on the new elements in terms of the locking free properties and sharper resolution of the discontinuities that propagate in arbitrary directions.

Advisor: Armero, Francisco
An Empirical Study of the Process of Crafting and Using Definitions

In this dissertation I analyze the process of crafting definitions whose purpose is classification. The context I examine is undergraduate upper-division physical science majors defining and naming sub-categories of a physical phenomenon in the context of a design task over an extended period of time. The goal of the design task is one of classification: help people better identify the phenomenon out in the world./nI first develop an analytic framework for the process of improving a definition. This framework involves an interplay between four main elements: the current state of the definition, criteria for what makes a good definition, examples, and definitionally unarticulated knowledge (DUK). By DUK, I mean implicit judgments that definers make about categorization that have not been incorporated into the definition, per se. I show how criteria and the practices associated with meeting them guide the refinement work./nOnce participants craft their definition a question emerges: to what extent does it serve them as a tool when they make sense of new examples? I zoom in on moments where new examples are introduced by participants or the facilitator and describe the extent to which students rely on their own crafted definition. The consideration of a new example can sometimes lead to participants naming a new sub-category and I analyze this process as well./nThe detailed empirical analysis is bookended by a set of workshop design principles that made the analysis possible and some educational implications of the work. I lay out a set of design principles for creating activities wherein people engage productively in collaboratively defining. I conclude by exploring the educational implications for college physics teaching as well as more general instances where one is interested in crafting a definition for the purpose of classification.

Advisor: diSessa, Andrea A
Light Harvesting and Its Regulation in Photosynthetic Grana Membranes

Photosystem II (PSII) initiates photosynthesis in plants by absorbing and converting light energy from the sun into chemical energy, a process called light harvesting. PSII is composed of proteins bound to pigment cofactors that can be grouped into antenna proteins, which absorb light and transfer excitation energy to other pigment-protein complexes, and reaction centers, which can convert excitation energy into chemical energy via a charge separation reaction. In plants, the proteins associated with PSII are located in the grana membrane, which is densely packed with photosystem II and major light harvesting complexes (LHCII). PSII reversibly binds with LHCII to form PSII supercomplexes. PSII supercomplexes and LHCIIs form a large, variably fluid array of pigment-protein complexes that gives rise to an energy transfer network that operates like a "smart" solar cell. In dim sunlight, the grana membrane harvests light with 90% efficiency. In response to light of fluctuating intensity and wavelength, the antenna proteins of PSII can regulate light harvesting. Understanding the design principles of light harvesting in grana membranes in different light conditions would be useful as a blueprint for designing robust solar cells./nThis thesis presents measurements and models for understanding light harvesting in variable light conditions. We have developed the fluorescence lifetime snapshot technique to monitor changes in the energy transfer network of the grana membrane of green algae and plant leaves in response to changes in incident light. Using this technique, we suggest that there are two mechanisms for green algae to acclimate to changes in light intensity. To fully leverage the snapshot data, a structure-based model of energy transfer for the grana membrane is required. We constructed a detailed model of energy transfer and trapping in PSII supercomplexes and show how to use this model to construct an energy transfer model for the grana membrane. Together, the snapshot technique and membrane model will aid in the elucidation of the principles of light harvesting and its regulation in grana membranes.

Advisor: Fleming, Graham R
From Castus to Casticismo: Conceptions of Purity in Modern Spain

With the exception of the well-known figure of the ángel del hogar, concepts of purity in post-inquisitional Spain have rarely been used as central categories of analysis. This dissertation aims to address an important lacuna within nineteenth-century Spanish studies by tracing the complex ways in which purity, as an ideological regime, continued to operate as a less explicit but important construct in modern Spain. Rather than declining, such regimes metamorphosed into an array of discourses that positioned purity as a foundational ideological category for modern subjectivity and national identity in late imperial Spain. Specifically, I turn to the major realist novelists of the nineteenth century - Juan Valera, Leopoldo Alas, Emilia Pardo Bazán, and Benito Pérez Galdós -- to examine how realist fiction stages counter-narratives to essentialist notions of purity and impurity formulated and consequently deployed by Medicine, the Church, and the State. The dissertation traces the ways in which historical notions of pure lineage or pure blood underwrite "modern" and "post-inquisitional" notions of sexual, racial, and bodily purity, particularly in the last third of the nineteenth century, also known as the Restoration period./nI advance a critical understanding of these diverse forms of purity through what I identify as the discourse of casta. Originating from the Latin castus (clean, pure), casta can be translated into English as "caste" or "chaste," a profoundly revealing ambiguity that drives my analysis. Over the course of the dissertation I chart casta's semantic permutations including: female sexual purity (castidad); heritage, blood, and lineage (casta/o); and national purity (lo castizo/casticismo). The usage of casta/o and its related terms is always a gendered, racialized, and class-specific articulation of purity. The common thread that links these diverse definitions together, I argue, is the regulation of gender. Sexual purity, (and later racial, class- and national purity) is an implicit part of what casta evokes across its semantic evolutions. The texts examined here reveal that the discourse of casta is central to the production of idealized national subjects during a time of political instability and imperial decline. While casticismo appears to be fundamental to the production of the nation, its ambivalent and polyvalent nature complicates and at times undermines the success of nationalist projects

Advisor: Iarocci, Michael
Essays in Applied Economics

In this dissertation, I investigate the relationship between unemployment and grocery purchasing patterns with a particular focus on the health impacts of recession. The first chapter, I analyze food items and in the second chapter, I turn the focus on beer and cigarettes. Both of these chapters investigate possible mechanisms behind the documented phenomenon of decreased morbidity and mortality during recessions./nTo conduct the analysis presented in Chapter 1, I supplement five years of multi-market, multi-chain grocery scanner data with additional information on the positive health attributes of food products to create a unique dataset. First, I find no evidence that products with positive health attributes are systematically more expensive or promoted systematically less. They are, however, purchased on promotion less. Second, I match the scanner data with unemployment rate by market in order to conduct a reduced form analysis of changes in pricing, promotion and quantities sold given a macroeconomic shock. For overall grocery categories, prices go down, promotions weakly increase and overall quantities sold decline; results vary for products with health attributes. While shares for healthy products within category are unaffected by recession in some categories, in other categories I see a marked shift toward higher fat options within category./nIn Chapter 2, I again use retail scanner data to track price and quantity changes for beer and cigarettes subject to changes in unemployment rate. First, I find prices paid do not change significantly as a function of unemployment rate. Next, I find that the percentage of beer and cigarettes purchased on promotion is not significantly related to unemployment rate per se; that said, there is evidence of a period of experimentation with in-store cigarette promotions following the Tobacco Master Agreement that coincided with the 2001 recession and led to more cigarettes being purchased on promotion overall during that period. However, this period of strong in-store promotions gave way to fewer overall purchases made on promotion as states strengthened tobacco regulations in the early 2000's. The quantity of beer sold in supermarkets, which accounts for about 40 percent of total beer sales, and drug stores seems mostly unchanged by recessionary conditions; however, cigarette quantity sold has a modest negative relationship with unemployment./nTaken as a whole, this work suggests that average grocery purchasing patterns do not change greatly due to increases in average unemployment rate. While not entirely inconsistent with the hypothesis that decreased morbidity and mortality during recessions may be due to decreased smoking rates or better eating habits, the small magnitude of the overall effect suggests other mechanisms or heterogeneous effects might be at play.

Advisor: Villas-Boas, Sofia
Software for prediction and estimation with applications to high-dimensional genomic and epidemiologic data

Three add-on packages for the R statistical programming environment (R Core Team, 2013) are described, with simulations demonstrating performance gains and applications to real data. Chapter 1 describes the relaxnet package, which extends the glmnet package with relaxation (as in the relaxed lasso of Meinshausen, 2007). Chapter 2 describes the widenet package, which extends relaxnet with polynomial basis expansions. Chapter 3 describes the multiPIM package, which takes a causal inference approach to variable importance analysis. Section 3.7 describes an analysis of data from the PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study (Rahbar et al., 2012; Hubbard et al., 2013), for which the multiPIM package is used in conjunction with the relaxnet and widenet packages to estimate variable importances.

Advisor: Hubbard, Alan E.