VictorJuiz/thesis huggingface dataset:
Designing Automated Assistants for Visual Data Exploration

Visual data exploration enables analysts to identify trends and patterns, generate and verify hypotheses, and detect outliers and anomalies. However, the overwhelming number of decisions required in visual data exploration presents a barrier to discovering useful, actionable insights from data. To address this challenge, in this dissertation, we investigate how automated assistance via tooling aids visual data exploration./nWe introduce four systems to survey the design space of visual exploration assistants across different analytical tasks and interface modalities. We first describe VisPilot and Zenvisage++, two novel visual exploration assistants that accelerate the data exploration process for individual visual analysis tasks: drill-down analysis and pattern search. Next, we examine visual exploration assistants aimed at supporting multiple types of visual analysis tasks. We introduce Frontier, a general-purpose visual exploration assistant within a GUI-based charting tool that recommends potential next steps in a mixed-initiative visual analysis workflow. We further develop Lux, a general-purpose visual exploration assistant situated within a computational notebook that provides proactive, always-on recommendations within an exploratory programming workflow. Findings from this dissertation contribute towards designing an intelligent visual exploration assistant that suggests helpful tailored feedback based on user’s analytical needs and seamlessly guides users towards data-driven insights.

Advisor: Parameswaran, Aditya G
Long-term Radiation Monitoring Strategies after Nuclear Power Plant Accidents

Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, radiation measurements and monitoring have been conducted continuously. Radiation air dose rate datasets have been archived extensively in this area. There are several different types of measurements: fixed-point measurements, walk surveys, car surveys, airborne surveys, and monitoring posts. They have different spatial coverage, footprints, and uncertainty. Currently, the monitoring program is expected to transition to long-term monitoring after ten years’ monitoring. The challenge of long-term monitoring is to build a cost effective and sustainable strategy for minimizing the cost associated with the number of monitoring locations or sampling, while maximizing the ability to meet the objectives of long-term monitoring./nThis study aims to develop the long-term radiation monitoring strategies after the FDNPP accident. In this dissertation, we tackle three key challenges: (1) multiscale spatial data integration, (2) monitoring optimization, and (3) spatiotemporal data integration. First, we developed an efficient algorithm for integrating the multiscale data sets; the algorithm is based on Kriging to estimate the dose rates for unobserved locations. Secondly, we developed a strategy and an algorithm to optimize the monitoring post placement and their number. This strategy is designed in order to reduce the number of sensors while capturing spatial heterogeneity. The algorithm is based on Gaussian process model to capture and estimate the heterogeneity of air-dose rates across the domain. Lastly, we built a Kalman-filter based algorithm combined with Gaussian Process Model to predict the spatial–temporal distribution of radiation dose rates. We expect that these methods will have valuable contributions for the long-term monitoring in the Fukushima region, but also for the preparation for the future nuclear accidents.

Advisor: Wainwright, Haruko
Solution Processed Electronics for Flexible Hybrid Electronic Systems

Recently, form factors of electronics have been changing from conventional rigid electronics to more novel and complex form factors including soft, flexible, and even stretchable forms. These unique form factors are lightweight and enable conformal interfaces between electronics and the objects they rest upon. Printing is a commercially viable manufacturing technology for fabricating these types of electronics, capable of depositing materials including conducting, insulating, and semiconducting materials. However, printed flexible electronics are not as efficient as silicon integrated circuits (ICs) in certain regimes, such as computation or communication. Flexible hybrid electronics (FHE) leverage the benefits of flexible printed electronics and ICs by combining the two onto flexible substrates./nIn this dissertation, I will discuss the various components of an FHE system and the range of printing techniques that are used to fabricate them. This dissertation will also overview specific works highlighting advancements in developing FHE systems. For passive sensing applications, I will focus on our work on screen-printed thermistor arrays, and their applications in battery health monitoring. For active sensing applications, I will discuss our work using doctor-blade coated arrays of organic light-emitting diodes (OLEDs) and organic photodiodes (OPDs) for reflection mode blood oximetry, which accurately measures pulse rate and oxygenation. In addition to the discussion of the flexible sensor composed of OLEDs and OPDs, I will present our work on various unique geometries of optoelectronics and their significance in improving sensor efficiency. For power sources, I will present our work on screen-printed Zn-Ag2O battery arrays, and the scalability of these devices. Finally, I will discuss other techniques to develop robust conformal electronics, using a class of FHE systems called in-mold electronics.

Advisor: Arias, Ana C
Synthetic Studies Towards Quassinoid Natural Products and Development of a Copper-Catalyzed Double Coupling

Innovative carbon-carbon bond forming reactions have been integral to the synthesis of a myriad of complex molecules such as densely functionalized terpene natural products. Key to this effort is the development of novel methodology to generate strategic carbon-carbon bonds to rapidly access complex scaffolds. This dissertation describes a novel approach to the quassinoid natural products and the development of new methodology to help realize this goal. In Chapter 1 we provide an introduction to the quassinoid family of natural products including isolation, structural elucidation, the proposed biosynthesis, biological activity, and previous syntheses. In this chapter, we seek to provide the context with which our synthetic approach is based. Previous total syntheses of quassinoid natural products were hampered by lengthy oxidation sequences following construction of the carbon scaffold. To this end, in Chapter 2, we proposed to leverage the pseudo-symmetry of quassin to construct the carbon scaffold in tandem with the oxidation. To implement this strategy, we developed a novel copper-catalyzed double coupling of epoxy ketones to generate highly diastereo- and regioselective pseudo-symmetric products. We then extended this methodology to couple two different units in a three-component coupling. Finally, to conclude this chapter, the previously developed methodology was applied to the synthesis of the quassinoid core architecture. Having laid the foundation, in Chapter 3, we seek to extend our copper-catalyzed methodology to the construction of quaternary centers and ultimately the full quassinoid carbon skeleton; however, an unexpected rearrangement occured during dioxene cross coupling making a tandem allylic substitution/cross- coupling transformation unfeasible. We therefore surmised that any approach moving forward would need to first generate the quaternary center at the A/B-ring junction prior to dioxene cross-coupling. Accordingly, we first constructed a bicyclic using an ene/condensation/alkylation sequence before elaborating our system with dioxene. Finally, we are able to rapidlyassemble an advanced intermediate containing all the carbons necessary for construction of C19 quassinoids and set the foundation for future work in this area.

Advisor: Maimone, Thomas
Experimental studies of water wave forces on submerged plates and a low-cost image-based way to characterize wave shapes

Accurately determining water surface elevation and wave shapes in the hydraulic laboratory is critical for experimental research and physical understanding of ocean waves. Existing technologies such as wave gauges cannot capture the continuous wave profile across both space and time. This poses an issue, as nonlinear wave characteristics vary as a function of position and cannot be fully described using such point measurements. Furthermore, wave gauges are intrusive to the flow field. Alternative single-camera methods can't capture wave characteristics in a large field-of-view properly without sacrificing resolution. In the first part of this thesis, we propose an easy-to-use, low-cost method for measuring wave height and shape along the length of the flume over time. The method utilizes stitching of multiple web-cameras and the application of a Canny-based edge detection algorithm with experimentally determined thresholds and additional filters for maximum robustness and efficacy. Additionally, distortion correction is implemented in a computationally efficient manner. Video is acquired by three Logitech C920 PRO HD cameras recording at a resolution of 1280x720 at 24fps. The wave generator can generate waves with frequency between 0.1Hz and 1Hz. The experimental results show that wave height measurements can be obtained with a maximum resolution of 0.83mm with a relative error of $\pm1.5\%$ when compared with a reference wave gauge measurement. This work demonstrates the ability to arbitrarily extend the horizontal field-of-view while providing more accurate measurement results. The second part of this thesis discusses experimental studies of vertical water wave forces on the submerged plate. Submerged plates can serve as a model for submerged wave energy converters. Newly developed floating wave energy converters are designed to be submerged under the water surface to survive harsh ocean environments. These wave energy converter designs require a better understanding of the vertical wave load on submerged plates to help minimize the production cost while maintaining survivability. These experiments investigate a range of plate lengths and submergence depth ratios. The experimentally measured normalized vertical wave force results are compared with those of a linear wave finite element method model.

Advisor: Alam, Mohammad-Reza
A Chemist’s Approach to Graphene Nanoribbon Electronics

As semiconductor electronics are miniaturized to nanometer dimensions, new materials and device concepts are needed to meet the increasing demand for performance and energy at scale. A paradigm shift towards electronic components built at the molecular level is necessary to keep pace with this demand while maintaining the precision requirements and miniaturization trend set by the semiconductor industry. Bottom-up synthesized graphene nanoribbons (GNRs) are ideal candidates for this new paradigm due to their widely tunable electronic properties enabled by atomically precise synthesis from molecular precursors. GNRs have the potential to improve existing semiconductor technology while paving the way towards transformational semiconductor electronics based on tunneling devices, quantum bits, and spin transport. With the outstanding potential of GNRs comes a number of integration challenges to these applications. Chapter 2 of this dissertation introduces challenges faced to GNR integration into CMOS transistors and sensors related to (i) aggregation, (ii) structural homogeneity, and (iii) reproducibility that all serve to degrade device performance and yield. Chapter 3 introduces a method to synthesize atomically-thin, covalently-bonded 2D films of GNRs that resolves (i) aggregation and (iii) reproducibility challenges, resulting in improved device yield and performance. Further, Chapter 4 outlines a novel transfer method that enables access to (ii) structurally homogenous, spatially isolated graphene nanostructures on virtually any substrate. Finally, with a handle on solving the major integration challenges to GNR electronics, the work in Chapter 5 demonstrates a method for accessing intrinsically metallic GNRs – the final component towards a transformational GNR-based tunneling device concept described in Chapter 1.

Advisor: Fischer, Felix R
Revealing coupled electronic-vibrational dynamics at conical intersections by attosecond transient absorption spectroscopy

Molecular dynamics in modern chemistry are typically viewed within the Born-Oppenheimer approximation, which assumes that electronic and vibrational states can be treated independently. However, the coupling of ultrafast electronic and nuclear motions at crossings between molecular electronic states known as conical intersections render this approximation invalid. Due to the ubiquitous occurrence of conical intersections among excited electronic states, the majority of photoinduced processes including light detection in the human eye and photosynthesis extend beyond the traditional Born-Oppenheimer framework of molecular physics. Attosecond transient absorption spectroscopy (ATAS) represents an ideal tool for investigating such regimes through the direct probing of conical intersections with attosecond XUV pulses. In this thesis, I will present the application of attosecond XUV pulses produced by high-harmonic generation to the observation of conical intersections in benchmark molecular systems. These studies center on the photodissociation of alkyl iodides (R-I, R = C\textsubscript{n}H\textsubscript{m}), a prototype class of reactions triggered by valence excitation in the UV. To excite and probe their dynamics, we develop and integrate a source of ultrashort UV pump pulses, based on nonlinear frequency mixing, into an ATAS setup. With this source, we first target \textit{i}-C\textsubscript{3}H\textsubscript{7}I and \textit{t}-C\textsubscript{4}H\textsubscript{9}I molecules, and directly reveal sub-100 fs conical intersection dynamics governing differences in their reaction outcomes. Next, we systematically extend our methodology to a series of alkyl iodides (CH\textsubscript{3}I, C\textsubscript{2}H\textsubscript{5}I, \textit{i}-C\textsubscript{3}H\textsubscript{7}I, and\textit{t}-C\textsubscript{4}H\textsubscript{9}I) with varying in R-group structure. Through ATAS, we discover that multidimensional vibrational motions and electronic state-switching at a conical intersection become progressively enhanced with increasing R-group complexity. These results demonstrate the potential of ATAS for elucidating the interplay of electronic and vibrational degrees of freedom defining non-Born-Oppenheimer molecular chemistry in nature.

Advisor: Leone, Stephen R.
Neumark, Daniel M.
Synchrotron-based Techniques for Studying Emergent Phenomena in Complex Oxide Heterostructures

This dissertation focuses on the study of complex oxide materials using synchrotron-based X-ray characterization techniques. Advanced synthesis methods allow oxide heterostructures to be built with atomic-layer precision, enabling the study of low-dimensional materials and creating a platform to easily manipulate key properties such as strain and electrostatic boundary conditions. Studies that focus on nanoscale heterostructures and emergent ordered phases require new techniques to study their properties, for which X-rays are invaluable. This work explores chiral polar textures (vortices and skyrmions) that emerge in ferroelectric/dielectric heterostructures and superlattices of PbTiO3/SrTiO3. To probe the structure and chirality of these phases, non-resonant hard X-ray diffraction and resonant soft X-ray diffraction are used. First, hard X-ray diffraction is used to characterize the structure of polar vortices and skyrmions. Next, to investigate chirality, resonant soft X-ray diffraction is used. Detailed circular dichroism measurements and reciprocal space scans are performed using resonant X-ray diffraction. Changes of the magnitude and sign of circular dichroism in reciprocal space reflect the three-dimensional structure of polar vortices and skyrmions. These structures have chiral arrays of electric dipole and quadrupole moments, and the scattering from these chiral arrays is modeled to reproduce the observations from resonant diffraction. Overall, this dissertation shows how the reciprocal space dependence of circular dichroism in resonant diffraction can be combined with theoretical modeling to sensitively probe the three-dimensional chiral structure of polar vortices and skyrmions. This technique can be extended to study ordered electric or magnetic phases in similar systems.

Advisor: Ramesh, Ramamoorthy
Ways of Perceiving

Listen to music, and you can feel a beat under the sounds. But you can feel it differently, while hearing the sounds as otherwise alike. Heard each way, the music sounds different. But there is no difference in what seems to happen around you. Instead, you perceive the same events in different ways. What are these ways of perceiving? And how do they affect how things appear? I develop a view that answers these questions, and explain how the view resolves longstanding problems about temporal, spatial, and color perception.

Advisor: Martin, Michael
Campbell, John
The social cost of ecosystem loss and degradation

Effective, fair, and efficient policy designed to manage ecosystems requires that we quantify the benefits these systems provide to society – so that they can be weighed against the costs of environmental regulation. A large ecological literature documents how ecosystem loss and degradation affect environmental outcomes, but these changes are difficult to price because many of the societal benefits ecosystems provide lack a formal market and are therefore absent from society’s balance sheet. This dissertation aims to fill this knowledge gap by systematically evaluating the effects of changes in ecosystem conditions on human well-being. I focus on natural endowments that have plausibly large social values but face significant challenges to their persistence and health. The first two essays provide new estimates of how large-scale disturbances to forests and wetlands affect market and non-market outcomes. By quantifying the value of benefits that these ecosystems provide, my findings can assist decision makers in trading off the costs and benefits of environmental protection. To facilitate future research into the economic and social value of other natural resources, the final chapter of my dissertation develops a new research design to estimate causal effects in cross-sectional settings. I then demonstrate the efficacy and utility of this approach by providing new estimates for the effect of average climate and soil conditions on agricultural yields – relationships notoriously confounded by unobserved farmer and location characteristics but crucial for guiding economic and policy decisions.

Advisor: Hsiang, Solomon M
Shapiro, Joseph S
Towards High-Endurance, Nonvolatile, CMOS-Compatible Ferroelectric Memories for Next-Generation Computing

As modern computing workloads become more and more data-centric, there has been an increasing need in recent years to develop memory solutions which can adequately pro- vide the high performance, speed, and energy efficiencies required by data-intensive applications. Simultaneously, with the timely discovery of ferroelectricity in a well-investigated CMOS-compatible material – hafnium oxide, or HfO2 – memory devices integrating ferroelectrics have also made a resurgence on the nonvolatile memory landscape./nThis work presents the ground-up development of a novel CMOS-compatible ferroelectric oxide, doped HfO2, and demonstrates its successful integration into ferroelectric memory capacitors (FeRAMs), transistors (FeFETs), and content addressable memory cells (FeCAMs). As HfO2-based memories are still a nascent technology, special emphasis is placed on developing a deeper physical understanding of the various engineering challenges associated with process integration and device performance. Underlying reliability concerns related to limited cycling endurance and premature device failure are identified, and methods to mitigate some of these bottlenecks are presented and investigated. Based upon the understanding derived from identifying the physical root causes for degradation, a highly effective gate oxide engineering technique for boosting the endurance metric of the FeFET by roughly 5 orders of magnitude, which enables the highest endurance numbers reported on FeFETs with a crystalline silicon channel to date, is demonstrated. Lastly, the successful fabrication and characterization of content addressable memory cells based on the FeFET is reported. The simple 2-FeFET FeCAM cell boasts both nonvolatility and substantially smaller on-chip footprint in contrast to its existing SRAM-based CMOS counterpart./nThe overall objective of this work is to provide a pathway forward for continued development on a CMOS-compatible nonvolatile memory element that can be used for embedded memory applications or for in-memory computing. The operational properties of the doped HfO2-based FeFET, in considering its intrinsic fast write/read speeds, low voltage requirements, and retention robustness, makes it well-suited to accommodate demanding modern computational needs by sealing the gaps between conventional memory, logic, and continued device scaling.

Advisor: Salahuddin, Sayeef
Macroecological Patterns Out Of Steady State

Prevalent macroecological patterns have been identified across a wide range of ecosystems, and these patterns have proven effective for understanding ecosystems at scales relevant for conservation and management. However, empirical studies and macroecological theory to this point have largely focussed on static patterns for ecosystems in steady state, and there is increasing interest in understanding how these metrics change over time and in respond to disturbance./nIn my dissertation, I use the Maximum Entropy Theory of Ecology (METE) as a starting point to predict how ecosystems will respond to disturbance and analyze the corresponding shifts in macroecological patterns. METE uses the principal of maximum entropy to predict various macroecological patterns and has proven effective for ecosystems at steady state, though its predictions appear to fail for disturbed ecosystems. The first chapter of my dissertation studies how deviations from METE predictions can inform us about underlying biology by studying macroecological patterns across land uses of different intensities for arthropods in the Azores. I then look at how we can modify METE to improve its predictions for ecosystems out of steady state. In my second chapter I present a new model that extends the spatial predictions of the theory to include intraspecific negative density dependence. Finally, in my third chapter I discuss my work developing DynaMETE: a new hybrid theory of macroecology that combines the maximum entropy methods of METE with explicit mechanisms to predict how patterns change in time. I present a method for iterating this theory in time, and code that implements this iteration scheme./nEcosystems are faced with increasing levels of human disturbance from habitat fragmentation, to land management, to climate change. This makes it important to study macroecological patterns out of steady state as we work toward understanding how ecosystems will respond to disturbances at the large scales relevant for conservation and management.

Advisor: Harte, John
Hallatschek, Oskar