VictorJuiz/thesis huggingface dataset:
Magnetoresistive and magnetostrictive sensors for the mobile era

Magnetoresistance is the property of a material to change the value of its electrical resistance in an external magnetic field, which has been utilized in a variety of sensing applications. Magnetostriction is the phenomenon of a magnetic body to change its shape and dimension as a function of an applied magnetic field. Magnetostrictive materials have been widely used as bulk resonators in electrical article surveillance system and studied for small-mass-detection-based portable sensing applications。 The first part of this work focuses on developing magnetoresistive and magnetostrictive sensors towards higher accuracy, higher sensitivity, and smaller physical sizes for mobile applications. Here a new methodology has been developed to guide the sensing system design. Besides, we have fabricated magnetostrictive resonators with miniaturized sizes and much larger resonant frequencies. Moreover, the resonant signals maintain good signal-to-noise ratios and quality factors. Second, a novel anisotropic magnetoresistive (AMR) angle sensor with multilayer material stack has been proposed and fabricated. Compared with traditional single layer sensors, our fabricated quadruple-layer AMR angle sensors have improved the sensing accuracy by a factor of 5. In addition, the quadruple layer AMR angle sensor demonstrates good detection accuracy even at small magnetic fields, which helps to lower the requirement of hard magnets in AMR angle sensing system Finally, the development of AMR angle sensors with stray field immunity is discussed. The signal of AMR angle sensors can be corrupted with significant errors due to the existence of stray fields in real application environments. Here we have designed a new system consisted of four AMR angle sensors along with a multipole magnet. Using the output signals from all the four sensors, the errors from stray fields are effectively reduced, which enables the implementation of AMR angle sensors in a wider range of applications

Keywords: Materials Science and Engineering.
Advisor: Wang Shan X. 
Dauskardt R. H. (Reinhold H.)
Suzuki Yuri (Applied physicist)
Making causal conclusions from heterogeneous data sources

The modern proliferation of large observational databases -- in fields such as e-commerce and electronic health -- presents challenges and opportunities for applied researchers. Such data can contain rich information about causal effects of interest, but the effects can only be estimated if we make untestable assumptions and carefully model the assignment mechanism. Experimental data provides a "virtuous" counterpart for the purposes of inferring causal effects, but randomized trials are often limited in size and, consequentially, lack precision. In this thesis, we consider problems of "data fusion, " in which observational and experimental datasets are used together to estimate causal effects. The problem is considered from three angles. First, we develop methods for merging experimental and observational causal effect estimates in the case when all confounding variables are measured in the observational studies. Next, we remove the unconfoundedness assumption, which leads to a new class of estimators based on a shrinkage approach. Finally, we propose a novel solution for designing experiments informed by observational studies, making use of the regret minimization framework. Throughout, we deploy tools from disparate areas of the literature, including Empirical Bayes, decision theory, and convex optimization

Keywords: Statistics.
Advisor: Baiocchi Michael
Owen Art B.
Palacios Roman Julia Adela
Making sense of the feedback loop between the media and the criminal justice system

My dissertation focuses on the connections between criminal law, race, media, and society. Adopting an interdisciplinary approach, I focus on three interrelated components: the criminal law in action, in particular sentencing decisions; media representations of crime, criminals and victims; and how the interactions between these institutions and representations shape the criminal justice system. My dissertation aims to push the scholarship on the effects of mass media on the criminal justice system a step forward, and to empirically assess and explain both the existence and the magnitude of such effects, with particular attention to the treatment disadvantaged minorities receive from the criminal justice system. My first two papers explore racially skewed media representations of defendants and victims, and discuss how these representations dominate the criminal justice system and affect criminal law and policy. The third paper investigates how increased coverage on crime leads to increased harshness in sentencing among judges in state trial courts, and explain these relationships based on the media's role in instilling fear of crime in society. Utilizing mainly quantitative research methods, I bridge a gap in the empirical scholarship and provide evidence to better understand the feedback loop between the media and the criminal justice system. I demonstrate how institutional dynamics shape social learning on crime in society, corroborate stereotypical thinking, and preserve and perpetuate inequalities in the criminal justice system. By doing so, I go beyond traditional institutional exploration of the criminal justice system to provide a more holistic view of how Americans in general, and legal professionals in particular, perceive and discuss crime in society. Moreover, I offer a novel multidisciplinary lens to address recurrent themes in the scholarship on racial disparities in the criminal justice system

Keywords: Law JSD.
Advisor: Engstrom David Freeman 
Donohue John J.
Iyengar Shanto
Many Faces of Many-Body Quantum Chaos: From Periodic Orbits to Semiclassical Fields and Back

The conventional paradigm for statistical physics starts with the assumption that all microstates of an isolated system are equally probable in equilibrium. In classical mechanics, due to inherent non-linearities in the equations of motion, an ensemble of states concentrated in a small region of phase space very rapidly explore the entire allowable phase space. This ergodic property justifies the fundamental statistical assumption. In quantum mechanics, however, Schrodinger evolution is always linear in Hilbert space and ergodicity in the naïve sense does not apply. In this thesis, we explore one notion of quantum ergodicity: random matrix statistics of the energy spectrum. For few-body quantum systems that admit a semiclassical limit, Andreev et al. (arXiv:cond-mat/9601001) have proven that this notion of quantum ergodicity follows directly from the classical notion of ergodicity. We extend this work in two ways, first to many-body quantum systems (including various large N systems familiar in high energy physics) with emergent semiclassical limits, and then to a class of many-body Floquet spin chains with no semiclassical limit. In the end, we discuss limitations of our approach and make some comments on future directions to pursue.

Keywords:  Department of Physics
Quantum Chaos
BGS conjecture
Large N systems
Floquet systems
Quantum Dynamics
Thesis
Advisor: Hartnoll Sean
Shenker Stephen
Many-body spin dynamics with rydberg-dressed atoms

A fundamental challenge of quantum science is to introduce controllable interactions in well isolated quantum systems. One approach is to excite neutral atoms to Rydberg states, thereby creating optically controlled long-range interactions. In order to take advantage of both the long-range interactions of the Rydberg states and the long spin-coherence times of ground-state atoms, we off-resonantly couple a cold dilute gas of cesium atoms to Rydberg states, using the technique of Rydberg dressing. In this thesis, I present the first experimental realization of the transverse-field Ising model with Rydberg dressing. We first demonstrate the creation of Ising interactions and characterize them via Ramsey spectroscopy. We observe one-axis twisting dynamics, a step towards creating spin-squeezed states with finite range interactions. By adding a periodic microwave drive, we are able to detect dynamical signatures of the paramagnetic-to-ferromagnetic phase transition. These results highlight the capability for locally and dynamically controlling the interaction strength. The apparatus constructed to realize these interactions additionally includes capabilities of quickly switching on and off the atomic interactions and dynamically changing the sign of the interactions. This work paves the way for many applications requiring spatiotemporal control of interactions in the fields of quantum simulation, quantum optimization, and quantum metrology

Keywords: Applied Physics.
Advisor: Kasevich Mark A.
Schleier-Smith Monika
Hollberg Leo (Leo William)
Mapping functional and structural plasticity in the adult brain with novel volume imaging-based methods

The brain's capacity to reorganize is thought to diminish with age, yet ongoing anatomical plasticity in mature neural circuits is critical for functions like learning, memory, and the ability to recover from neurological injury and disease. Organismal experience can induce activity-dependent changes in axons, including outgrowth, branching, elongation, pruning, and elimination. Such changes have been well-studied during the "critical period" in early postnatal life. Changes of this nature have also been documented in the adult, but the logic, timing, and magnitude of axonal dynamics in this setting, and the molecular mechanisms that mediate them, remain poorly understood. This is due, in part, to the difficulty of developing robust systems to visualize and quantify concurrent structural, functional, and molecular changes across large volumes of the intact brain in 3D. In this dissertation I present several novel approaches to surmount this challenge, and I apply them to the study of activity-dependent axonal reorganization in the adult. First, I discuss critical improvements made to a whole-mount immunolabeling and tissue-clearing method called iDISCO which enable the automated registration of large cohorts of samples, imaged in volume by light sheet microscopy, to a standard reference brain atlas. Second, I describe the creation and optimization of a computational toolkit for the quantitative image analysis of immunolabeled structures in 3D. Third, I validate a data production pipeline combining these two innovations by mapping whole-brain perturbations in molecular markers of activity following acute and chronic sensory deprivation. Fourth, I employ novel viral and genetic tracing strategies to label, perturb, and quantify changes in activity-defined subcircuits following chronic sensory deprivation. Specifically, I demonstrate that different subcircuits in the mouse whisker barrel system follow different reorganizational rules, while the molecular mechanisms underlying their execution may be shared. This work advances our understanding of axonal plasticity in the adult brain and lays a methodologic foundation for future studies to systematically explore causal links between molecular, structural, and functional changes in intact neural circuits in both health and disease

Advisor: Luo Liqun
Tessier-Lavigne Marc
Huguenard John
Monje-Deisseroth Michelle
Shatz Carla J.
Marijuana in NYT

Within the last few decades, the valence of marijuana on the stage of public
opinion has changed dramatically. As of 2020, 33 states have legalized
medical marijuana, and eleven have legalized marijuana for recreational use.
In this paper, I use word embeddings to explore changing media framing of marijuana, applying a potentially more granular methodology to see how media representations of charged topics change over time.

Keywords: marijuana
distributional semantics
word embeddings
cannabis
media
Thesis
Market structure and dynamics

This thesis consists of three self-contained essays that investigate the algebraic structure of matching markets and the stabilization dynamics in decentralized markets. Chapter 2 is based on Wu and Roth (2018). It studies envy-free matchings that naturally arise from workers retiring or companies expanding. We show that the set of envy-free matchings forms a lattice that has a Conway-like join, but not a Conway-like meet. Furthermore, a job hopping process in which companies make offers to their favorite blocking workers, and workers accept their favorite offers, producing a sequence of vacancy chains, is a Tarski operator on this lattice. The fixed points of this Tarski operator correspond to the set of stable matchings; and the steady state matching starting from any given initial state is derived analytically. Chapter 3 is based on Wu (2020). The goal of this chapter, is to provide a systematic approach for analyzing entering classes in the college admissions model. When dealing with a many-to-one matching model, we often convert it into a one-to-one matching problem by assigning each seat of a college to a single student, instead of matching each college to multiple students. The preferences in this new model are significantly correlated and severely restrict the possible changes to entering classes. Through the so-called "rotations" that correspond to the join-irreducible elements in the lattice of stable matchings, we present a unified treatment for several results on entering classes, including the famous "Rural Hospital Theorem". We also show that, the least preferred student in an entering class appears to play a very interesting role. For example, each entering class can be completely characterized by its worst student. Chapter 4 is based on Gu, Roth, and Wu (2020). The motivating question is that, how come some black markets, such as the market for hitmen are well-regulated, but many others like the market for drugs are far from being under our control, even though we try very hard to eliminate them. To understand this, we build a three-dimensional discrete time Markov chain to study how black markets evolve over time, focusing on social repugnance and search frictions. We borrow tools from Markov jump processes, random walks, exponential martingales and optional sampling theory to analyze both the steady state limit and the realizations along the way. In the first part of the chapter, we identify conditions that lead to market survival or extinction. And the second part studies speed of convergence. We show that if a market is going to die eventually, then it dies exponentially fast. This further implies if a market has survived for a long time, then it is likely to survive forever

Keywords: Economics.
Advisor: Roth Alvin E.
Ashlagi Itai 
Kojima Fuhito
Markets, morality, and the environment

Environmental governance scholarship typically considers how to use financial and legal incentives to encourage firms to internalize externalities. This dissertation examines how moral identity concerns and social influence—the desire to look and feel like a moral actor, and the social context in which an act occurs—can also shape regulation and firm behavior. Chapter 1 employs eight sets of studies to empirically evaluate patterns of moral judgment and so contribute to a deeper understanding of moral identity concerns. Applying those patterns of moral judgment to policy, Chapter 2 tests tradeoffs in proposals to alter corporate director fiduciary duties and thus encourage greater corporate social responsibility. I combine an analysis of legal doctrine and theory on motivational crowding to inform three preregistered experiments with over 900 participants. I find that mandating consideration of society—as compared to merely allowing such consideration—can backfire by reducing the reputational rewards for prosocial action. Chapter 3 explores behavioral distinctions between economically equivalent market-based price- and quantity-regulatory regimes (e.g., pollution tax and cap-and-trade programs). Using a preregistered experiment with over 500 participants, the chapter finds that negotiators reach more environmentally protective tax than cap-and-trade policy deals. This dissertation contributes to a better understanding of the social and moral influences that shape regulation and firm behavior

Advisor: Miller Dale T. 
Thompson Barton H.
Lambin Eric F.
MacCoun Robert J.
Markups to financial intermediation in foreign exchange markets

Even in deep, liquid asset markets, financial intermediaries may have market power. To identify the effects of market power on asset prices, I study foreign exchange market arbitrages implied by deviations from covered interest rate parity. Previous literature equates these arbitrages to the shadow price of a balance sheet constraint on foreign exchange dealer banks. My work identifies cross-sectional variation in arbitrage returns that is inconsistent with the standard balance sheet constraint channel. My identification strategy relies on cross-country differences in the enforcement of capital constraints that decrease competition near quarter-end. Using a model of imperfect competition, I decompose CIP arbitrage returns into balance sheet cost and markup. Markups explain a significant portion of CIP arbitrage returns

Keywords: Business.
Advisor: Hebert Benjamin 
Krishnamurthy Arvind 
Duffie Darrell 
Lustig Hanno 
Somaini Paulo
Massive MIMO and robust modulation for high-performance wireless systems

First, we consider physical layer cryptography in the context of the computational complexity associated with desired and undesired receivers decoding signals from massive MIMO arrays. We show that under proper conditions, decoding a massive MIMO signal by an eavesdropper is at least as hard as solving standard lattice problems that are conjectured to be prohibitively complex to solve even with a quantum computer. We use this result to design a wireless system where two users can reliably communicate with low overhead but decoding by an eavesdropper is prohibitively complex. Next, we study MIMO decoding when channel state information (CSI) is unknown to both the transmitter and receiver. We present an algorithm that leverages concepts of linear and mixed-integer linear programming to efficiently perform blind decoding with similar error probability as decoding under perfect CSI. Moreover, measures of the runtime of this algorithm suggest that the real-time blind decoding of MIMO signals is feasible for moderately large MIMO systems and offers several orders of magnitude increase in performance over existing techniques. Thus, our technique enables real-time blind MIMO decoding in rapidly time-varying channels with low probability of error. Finally, we present two novel modulation and detection techniques for channels that exhibit an arbitrary Doppler spread, assuming that the delay spread of the channel is low. These techniques, termed Frequency-Domain Multiplexing with a Frequency-Domain Cyclic Prefix (FDM-FDCP) and Single-Carrier Modulation with Time-Domain Equalization (SC-TDE), are able to compensate for the time variations associated with the Doppler spread. This compensation is done via a simple time-domain equalization method of comparable complexity to the frequency-domain equalization of OFDM. These modulation techniques are shown to outperform OFDM in terms of reliability and spectral efficiency in both high-mobility environments and in systems with high-carrier frequencies

Keywords: Electrical Engineering.
Advisor: Goldsmith Andrea
Kahn Joseph H.
Wootters Mary
Masterless renaissance : rogue form from Lazarillo to Cutpurse

Treating "masterlessness" as both a historical event and an evolving discourse, "Masterless Renaissance: Rogue Form from Lazarillo to Cutpurse" recovers one of the early modern period's central vocabularies for theorizing social change. Where much of early modern literature, and its criticism, investigates the subtle and contested dynamics of the master-servant dyad, this project moves beyond the paradigm of patronage and the English "rogue literature" which has so far dominated literary-critical discussion of early modern modes of labor and subjecthood, and turns toward the era's much less well understood emerging forms and conceptions of masterlessness. Masterless Renaissance shows how the idea of the masterless person transformed throughout the period from that of the social pariah—the rogue, outlaw, vagabond, and apostate—to the bourgeois ideal of freedom and autonomy. From Spanish picaresque fiction and its influential English translations, and Thomas Nashe's narrative invention to interrogate the mechanics of precarious commodification; to William Shakespeare's republican tragedies and their rich engagement with the notion of akrasia as a way to reckon with what Jürgen Habermas has termed the "disintegration" of the bourgeois public sphere; to Mary "Moll Cutpurse" Frith and Catalina "The Lieutenant Nun" Erauso, their criminalized cross-dressing mobility and questions of gender and imperial war machines, Masterless Renaissance reveals masterlessness as an overlooked complex of aesthetic innovation, incipient sociological paradigms, and an evolving philosophical and theological tradition

Advisor: Greene Roland
Lupic Ivan
Parker Patricia A.