VictorJuiz/thesis huggingface dataset:
Explainable and Advisable Learning for Self-driving Vehicles

Deep neural perception and control networks are likely to be a key component of self-driving vehicles. These models need to be explainable - they should provide easy-to-interpret rationales for their behavior - so that passengers, insurance companies, law enforcement, developers, etc., can understand what triggered a particular behavior. Explanations may be triggered by the neural controller, namely introspective explanations, or informed by the neural controller's output, namely rationalizations./nOur work has focused on the challenge of generating introspective explanations of deep models for self-driving vehicles. In Chapter 3, we begin by exploring the use of visual explanations. These explanations take the form of real-time highlighted regions of an image that causally influence the network's output (steering control). In the first stage, we use a visual attention model to train a convolution network end-to-end from images to steering angle. The attention model highlights image regions that potentially influence the network's output. Some of these are true influences, but some are spurious. We then apply a causal filtering step to determine which input regions actually influence the output. This produces more succinct visual explanations and more accurately exposes the network's behavior. In Chapter 4, we add an attention-based video-to-text model to produce textual explanations of model actions, e.g. "the car slows down because the road is wet". The attention maps of controller and explanation model are aligned so that explanations are grounded in the parts of the scene that mattered to the controller. We explore two approaches to attention alignment, strong- and weak-alignment./nThese explainable systems represent an externalization of tacit knowledge. The network's opaque reasoning is simplified to a situation-specific dependence on a visible object in the image. This makes them brittle and potentially unsafe in situations that do not match training data. In Chapter 5, we propose to address this issue by augmenting training data with natural language advice from a human. Advice includes guidance about what to do and where to attend. We present the first step toward advice-giving, where we train an end-to-end vehicle controller that accepts advice. The controller adapts the way it attends to the scene (visual attention) and the control (steering and speed). Further, in Chapter 6, we propose a new approach that learns vehicle control with the help of long-term (global) human advice. Specifically, our system learns to summarize its visual observations in natural language, predict an appropriate action response (e.g. "I see a pedestrian crossing, so I stop"), and predict the controls, accordingly.

Advisor: Canny, John
Electronic and Optical Properties of Materials for Energy-Related Applications

In this dissertation, I discuss the electronic and optical properties of materials for energy-related applications, with a focus on silicon (Si), gallium arsenide (GaAs) and the transition metal dichalcogenides (TMDs) in particular./nSi is the most widely used photovoltaic material today, dominating the photovoltaic industry by more than 90%. This is because Si is non-toxic, abundant and benefits from technologies developed over the years in the microelectronics industry. Despite its widespread usage as a photovoltaic material, Si does not efficiently absorb most of the light in the solar spectrum because it has an indirect bandgap. On the other hand, GaAs has a direct bandgap that is optimal for solar energy conversion, even though it is more expensive than Si and is also toxic due to the presence of arsenide. Nonetheless, in the atomically-thin film limit, both cannot be compared with the TMDs, absorbing significantly less light than the TMDs in the solar spectrum. This optical property of the TMDs makes them a very appealing class of candidate materials for flexible ultra-thin solar cells./nIn Chapter 1, I give an overview of the different approaches that we use to address different problems in this dissertation. In Chapter 2, I discuss our work that aims to understand how the structure of an alternative Si phase can lead to an improved calculated absorption relative to diamond-Si. In Chapter 3, I discuss how we can use first-principles to calculate the hot carrier dynamics in GaAs, such as by calculating its electron-phonon relaxation times. In the Chapters 4, 5 and 6, I discuss the electronic and optical properties of mono- to few-layer TMDs. Not only are their quasiparticle bandgap and exciton energy levels affected by dielectric screening due to substrates, the dielectric screening environment can also be modified to engineer an intrinsic lateral heterojunction within a homogeneous TMD monolayer. In Chapter 7, we report the first observation and control of the Berry-phase induced splitting of the 2p-exciton states in monolayer MoSe2, and in Chapter 8, we study that the dynamics of atomically-sharp lateral heterojunctions between differently-stacked TMD domains.

Advisor: Louie, Steven G
Writing the Postcolonial City: Phnom Penh and Modernity during Sangkum Reastr Niyum, 1955-1970

This dissertation examines novels, essays, films and songs of the Sangkum Reastr Niyum period, 1955-1970, to explore the layers of meanings Cambodians held of Phnom Penh. After the Geneva Accords in 1954, Phnom Penh emerged as the capital city of a newly independent nation-state, the Kingdom of Cambodia. The city under French colonial rule was secondary to Hanoi and Saigon, but once Indochina dissolved, its population exponentially increased. Phnom Penh was at the center of Cambodia’s road networks, its banking system, and was home to the best universities and schools. The many jobs and opportunities attracted rural migrants to the city. The population boom was one of the many ways Phnom Penh transformed. Norodom Sihanouk, then the head of state, made Phnom Penh the epicenter of government modernization projects. Under his watch, the capital transformed from being a marshy, provincial hub into an exciting scene of cosmopolitan innovation. Urban Cambodians combined ideas from Le Corbusier with traditional Khmer architectural details to design their “modern” buildings. Their songs were influenced by the French singer Johnny Halliday and the American Wilson Pickett. They wrote novels that built upon the ideas found in Buddhism and French Existentialism. Through their works, urban intellectuals sought to define a Cambodian identity independent of French colonialism. Phnom Penh, with its new roads, many schools, bars and publishing houses, was a space where Cambodians became modern and developed new identities, such as the neary samey tmey and the pannavoan./nThese changes to the landscape and social composition of Phnom Penh engendered a new consciousness amongst Cambodian intellectuals. Their writings expressed a concern over changes in heterosexual relationships and the behavior of Cambodians in public spaces. To some, not all the changes were good. They mourned the marshes and wooden shacks that asphalt and concrete had replaced. They were aware of ruptures, loss, and fragmentation. This consciousness of the new amongst urban Cambodian intellectuals is what I term postcolonial modernity. This study contributes to the history of Sangkum Reastr Niyum by taking seriously the historical value of Cambodian writings and focuses the lives of everyday urban Cambodians. It describes the Sangkum period as a time of unprecedent change that witnessed the emergence of a new urban middle class.

Advisor: Zinoman, Peter B.
The Linguistic Expression of Affective Stance in Yaminawa (Pano, Peru)

This dissertation explores affective expression in Yaminawa, a Panoan language of Peruvian Amazonia. In this study, ‘affect’ is used to refer broadly to the English language concepts of ‘emotion’ and ‘feeling’. Affective expression is approached as an interactional phenomenon and it is analyzed in terms of affective stancetaking, i.e., the way speakers position themselves to objects in the discourse as well as their interlocutors via linguistic performance. This study considers affective resources at the levels of the lexicon, morphology, prosody, acoustics (voice quality, speech rate and volume, etc.), and interactional features (turn duration, complexity of backchannels, etc.). This study contextualizes affective expression in Yaminawa with a detailed description of Yaminawa ethnopsychology and the lexical resources that describe affective states, as well as behaviors and bodily sensations that are associated with particular affects by the Yaminawa. Using methods from Cognitive Anthropology, I investigate the ways that native Yaminawa speakers categorize emotion terms, and show that prosociality vs. antisociality is a major cultural axis along which emotion terms are conceptually organized. This dissertation also provides both a general ethnographic sketch of daily life among the Yaminawa community of Sepahua and a grammar sketch of the Yaminawa language./nYaminawa is notable for its rich inventory of bound morphemes that are used in affective expression. Some of the affective categories expressed by these bound morphemes, such as sadness, appear to be typologically unusual. In everyday conversation, certain/nmorphological, acoustic, and interactional features cluster together in recurrent affective ways of speaking that are identifiable by speakers even when the propositional content of the utterances cannot be clearly heard. This dissertation describes two salient affective ways of speaking in detail: shĩ́nã̀ì ‘sad’ speech and sídàì ‘angry’ speech. Shĩ́nã̀ì ‘sad’ speech is characterized by creaky voice, low speech volume, and high frequency and complexity of backchannelling by co-participants, among other features. Sídàì ‘angry’ speech is characterized by breathy voice, slow and rhythmic speech rate, and scarcity and simplicity of backchannels. I also briefly describe the key features of three additional, minor affective stances: dúì ‘affection’, rátèì ‘surprise’, and bésèì ‘fear’. Some affective resources are used in more than one type of affective speech, for example, high pitch is used in affectionate speech, surprised speech, and commands issued in angry speech. Other affective resources appear to be unique to a single affective type, such as delayed stop release in fearful speech./nWhile previous descriptions of affective expression in individual languages have tended to focus on single levels of analysis, such as metaphor or morphology, this dissertation aims to provide a model for the holistic description of affective expression in an individual language.

Advisor: Michael, Lev D.
Ecological Genetics of Stipa pulchra in Environmental Restoration

Ecological restoration has become a large enterprise driven by regulatory policies and by public and private initiatives. Regulatory agencies and ecologists call for use of propagules that are adapted to project sites, compatible with other species, and genetically diverse. This project uses a native California grass, Stipa pulchra, to ask whether the cost-management practice of collecting seeds from dense stands of target species can have unintended selective effects on species used in restoration. Absolute cover, standing biomass, species composition, and S. pulchra density and culm count were recorded on plots in three central California sites. S. pulchra seeds from these plots were sown in pots allocated to two watering groups and three temporal blocks./nPot-study plants grown from seed collected from plots with greater absolute cover and S. pulchra density had significantly higher basal diameters, tiller counts, and root: shoot ratios. Plants derived from less-competitive plots reproduced earlier and gave rise to more culms. These results indicate that distribution of S. pulchra genoypes in the field may reflect a competition: colonization pattern, with more fecund S. pulchra plants inhabiting less-competitive patches than those occupied by their more-competitive conspecifics. Other aspects of pot-study plant growth appeared to reflect background vegetation of the field plots. Although plants grown from seeds collected at the three sites were significantly different, there was no evidence that ecological distance reflected geographic distance. Plants receiving more water had relatively greater aboveground growth and lower root: shoot ratios. Statistical interactions of blocking and watering treatments with site may reflect plant adaptation to climate and soil at the various sites. Implications of these results apply to environmental restoration and extend to ecological research, where nonrandomly collected propagules are often used to represent genetic characteristics of entire populations.

Advisor: Huntsinger, Lynn
Exploring Ensemble Coding in Retina

Computational models founded on the prevailing paradigm of retinal processing, while able to replicate the coarse structure of responses to white noise stimulus, fail to replicate responses to natural stimuli. The textbook view of retina, which posits independent filters that decorrelate stimulus features, reduce representational redundancy \cite{barlow1961} and encode local features in retinal ganglion cell (RGC) spike rates, leaves severe puzzles, unexplained about observed retinal anatomy and activity. We present, here, an addendum to the prevailing paradigm hypothesizing that \emph{perhaps}, the retina reduces uninformative correlations in stimulus with outer layers, as claimed, in order to reintroduce informative correlations, observed in RGC responses to ethologically relevant stimuli, with the circuitry in the inner retinal network (bipolar, amacrine, ganglions). Rather than strict independent coding and redundancy reduction, a notion which Barlow himself amended \cite{barlow2001}, we explore ensemble coding in retina and what information beyond the traditional view might exist in the retinal code. This work is in two related, yet independent parts. First, we develop a proof-of-concept abstract computational model of image segmentation using phase coding in the retina, hypothesizing that fine-time correlations in spike trains are induced by phase interactions influenced by the visual stimulus and that these fine-time correlations, informative about segments in an image, are multiplexed into spike-trains along with rate-coded local stimulus features. Following, we present a latent variable statistical model that aims to detect cell assemblies, or groups of cells that fire are often co-active, possessing fine-time correlations irrespective of their source and apply it to retinal spike-trains responding to both white noise and natural movie stimulus. The work presented here is novel and controversial and therefore, worth a read.

Advisor: Sommer, Friedrich
Feller, Marla
Point Defect Engineering of Energy Materials from First-Principles Calculations

Atomic scale imperfections, know as point defects, dictate the performance and efficiency of many modern energy materials. The challenges of climate change require the continued improvement and identification of materials which can have point defects engineered in a favorable fashion for the application of interest. With the rise of computer-aided materials design, the possibility of performing high-throughput, first-principles computation on point defects remains an attractive direction for improved screening of new energy materials. Yet major barriers have prevented the large scale implementation of point defect calculations in non-metals - namely, errors arising from the finite size of the computation cell, compounded with errors associated with the underestimation of the band gap. Moreover, the lack of an organized computational framework for storing and analyzing such calculations, as well as the lack of a reliable benchmark for understanding the quantities which can be reliably computed, have prevented high-throughput point defect calculations from being performed in a practical context. In this dissertation, the notion of performing first principles calculations of point defects in semiconductors and insulators in a high-throughput format is investigated. This begins with an overview of the theoretical requirements for performing first principles computation of defects, as well as the presentation of a set of open source command line tools for doing the same. Then three different application areas in the energy space - thermoelectrics for waste heat recovery, solid state electrolyte batteries, and solar cells - are explored with first principles calculations of point defects. Finally, scaling of the previously presented command line tools to a fully automated framework is demonstrated and used for a large benchmark study of fully-automated point defect calculations with semi-local functionals as compared to a set of previously published point defect calculations with hybrid-functionals. This benchmark work outlines the strengths and weaknesses associated with such an automation framework, and advocates for the use of such a framework for qualitative screening of doping limits and general carrier type for high-throughput computational discovery and design of new energy materials.

Advisor: Asta, Mark
Tropical Lagrangians and Homological Mirror Symmetry

We produce for each tropical hypersurface $V(\phi)\subset Q=\RR^n$ a Lagrangian $L(\phi)\subset (\CC^*)^n$ whose moment map projection is a tropical amoeba of $V(\phi)$. When these Lagrangians are admissible in the Fukaya-Seidel category, we show that they are mirror to hypersurfaces in a toric mirror. These constructions are extended to tropical varieties given by locally planar intersections, and to symplectic 4-manifolds with almost toric fibrations. We also explore relations to wall-crossing, dimer models, and Lefschetz fibrations. A complete example is worked out for the mirror pair $(\CP^2\setminus E, W), X_{9111}$.

Advisor: Auroux, Denis
Writing Spain: Race, Migration, and the Construction of the Pueblo

Abstract/nWriting Spain: Race, Migration, and the Construction of the Pueblo by/nHolly Jackson Weiss/nDoctor of Philosophy in Hispanic Languages and Literatures University of California, Berkeley/nProfessor Daylet Domínguez, Co-Chair/nProfessor Dru Dougherty, Co-Chair/nFocusing on literature from the twentieth century, this dissertation analyzes how intellectuals have represented the pueblo of Spain through the lens of personal or intergenerational experiences of migration and diaspora. The dissertation considers work by Southern Spaniards, Catalans, Latin Americans and North Africans on the Peninsula, asserting the centrality of postcolonial and plurinational figures—largely absent from Spanish cultural studies or confined to niche canons—to antifascist critiques of Spain. The dissertation focuses on the junctures that punctuate narratives of twentieth-century Spain: the Spanish Revolution and Civil War, the Franco dictatorship, and the Transition to Democracy. Noting the unresolved and discursive quality of these events, the dissertation looks at their representation in the work of Nicolás Guillén, Juan Goytisolo, Najat El Hachmi and others; these writers problematize the imaginaries of race, ethnicity and nation that are latent in official national narratives./nThrough analysis of the poetry of Latin American intellectuals, the dissertation shows antifascism in the Spanish Revolution and Civil War to be an anticolonial project, reconceiving the 1930s resurgence of transatlantic solidarity as a decolonial practice of critique. The dissertation then considers the mid-century turn to neoliberalism in Spain through analysis of an exilic memoir, arguing that the economic dispossession of Spain’s southern emigrants and the simultaneous rebranding of the Mediterranean coast as a postcard-ready paradise are the economic and representational legacy of colonial Cuba. From there, the dissertation analyzes two memoirs by Moroccan-born Catalans, arguing that Reconquista-era ethno-racial constructs are central to the discourse of Catalan identity that reemerged in the Transition to Democracy./nTracing the ways in which the (re)appropriation of the idea of Spain happens in the sign of the pueblo, the dissertation invokes this category as one that is as deconstructive as it is constitutive of Spain, and proposes pueblo as the nation in its erased, unofficial, nonlinear and pluralist histories, on the one hand, and as a hermeneutical category for imagining a community through critique of power relations, on the other. In its reading of transatlantic, transmediterranean and subnational constructions of the pueblo, the dissertation posits an archive that dismantles the homogenizing, centralizing and modernizing discourses of the last century in Spain.

Advisor: Dougherty, Dru
Domínguez, Daylet
Developments in the mathematics of the A-model: constructing Calabi-Yau structures and stability conditions on target categories

This dissertation is an exposition of the work conducted by the author in the later years of graduate school, when two main projects were completed. Both projects concern the application of sheaf-theoretic techniques to construct geometric structures on categories appearing in the mathematical description of the A-model, which are of interest to symplectic geometers and mathematicians working in mirror symmetry. This dissertation starts with an introduction to the aspects of the physics of mirror symmetry that will be needed for the exposition of the techniques and results of these two projects. The first project concerns the construction of Calabi-Yau structures on topological Fukaya categories, using the microlocal model of Nadler and others for these categories. The second project introduces and studies a similar local-to-global technique, this time used to construct Bridgeland stability conditions on Fukaya categories of marked surfaces, extending some results of Haiden, Katzarkov and Kontsevich on the relation between stability of Fukaya categories and geometry of holomorphic differentials.

Advisor: Shende, Vivek
Aganagic, Mina