VictorJuiz/thesis huggingface dataset:
Energy Efficient Communication Links for Smart Devices

With the continued development of new sensors, connected devices, and continued scaling data rates there is a serious data problem. This large amount of data needs to be communicated efficiently to where it needs to go for processing, logging or actions. There are many applications where the incoming data that needs to be communicated is not a continuous data rate, the required data rate and latency of the link change over time and settings, so a truly efficient system should be able to take advantage of this burst nature and operate accordingly./nFor the purpose of developing larger channel count systems for brain machine interfaces and neuroscience research, a compression algorithm is proposed to minimize the amount of data required to send by up to 700x. This would enable fully wireless systems with larger channel counts, with the main energy bottleneck still being the communication link. A low duty cycle burst mode millimeter wave phased array is proposed to further improve the energy efficiency of the entire system, enabling efficient wireless transfer of a scalable data rate over more than 1 to 100 Mbps. Similar design techniques to this communication link are also applied towards a high speed serial link design, tailored towards a large scale phased array system. The rapid on and off operation allows for a low latency communication interface throughout the entire array without overhead of a constantly operating link. This enhancement reduces the overhead power required to synchronize all of the elements, allowing for a more efficient overall system level design.

Advisor: Rabaey, Jan
An Implantable Radiation Detector for Cancer Radiotherapy

This dissertation presents a millimeter-scale CMOS 64x64 single charged particle radiation detector system for cancer radiotherapy; this work is applicable to therapies including external beam radiotherapy (EBRT), targeted radionuclide therapy (TRT), and brachytherapy. We demonstrate 1 um x 1 um diode pixels capable of measuring energy deposition into a depletion region by single charged particles. These pixels can be arrayed to provide large detection areas; we demonstrate a 512 mm x 512 mm array. Instead of sensing the voltage drop caused by radiation, the system measures pulse width, i.e., the time it takes for the voltage to return to its baseline. This obviates the need for power-hungry and large analog-to-digital converters. A prototype ASIC is fabricated in TSMC 65 nm LP CMOS process and consumes the average static power of 0.535 mW under 1.2 V power supply. The functionality of the whole system is successfully verified in a clinical 67.5 MeV proton beam setting, as well as MeV range electrons and X-ray beam produced by linear accelerator.

Advisor: Maharbiz, Michel M.
Anwar, Mekhail
In Silico Metabolic Modeling of Single Th17 Cells Reveals Regulators of Autoimmunity

Metabolism is a major regulator of immune cell function, but it remains difficult to study the metabolic status of individual cells with current technologies. Here, we present Compass, an algorithm to characterize cellular metabolic states based on single-cell RNA sequencing (scRNA-Seq) and flux balance analysis. We applied Compass to associate metabolic states with Th17 functional variability (pathogenic potential) and recovered a metabolic switch between glycolysis and fatty acid oxidation, akin to known Th17/Treg differences, which we validated by metabolic assays. Compass also predicted that Th17 pathogenicity was associated with arginine and downstream polyamine metabolism. Indeed, polyamine-related enzymes expression were enhanced in pathogenic Th17 and suppressed in Treg cells. Chemical and genetic perturbation of polyamine metabolism inhibited Th17 cytokines, promoted Foxp3 expression, and remodeled the transcriptome and epigenome of Th17 cells towards a Treg-like state. In vivo perturbations of the polyamine pathway altered the phenotype of encephalitogenic T cells and attenuated tissue inflammation in central nervous system (CNS) autoimmunity./nThe introduction highlights the motivation to this study, which stems from the conjunction of two transformative developments of recent years – the emergence of single-cell RNA sequencing technologies and the growing appreciation of cellular metabolism as key player in health and disease. Chapter 1 introduces lays the groundwork by introducing the fields of computational modeling of metabolism, immunometabolism, and single-cell genomics. Chapter 2 then introduces the Compass algorithm that serves as the computational framework to the rest of the study. Chapter 3 turns to T helper 17 (Th17) cells and emphasizes their diverse effector phenotype, which makes them an attractive system to query with computationally-informed metabolic methods. A Compass-based study reveals a parallel diversity of metabolic phenotypes within the Th17 cell type. In the next chapters we demonstrate our computational framework’s ability to discover metabolic regulators of Th17 inflammatory potential (pathogenicity). Chapters 4 and 5 complement one another; chapter 4 restricts its analysis to the well-studied central carbon metabolism pathways, whereas chapter 5 presents an unsupervised network-wide analysis that uncovers a novel metabolic regulator in the peripheral polyamine pathway. Chapter 6 follows on this discovery and shows that chemical and genetic perturbations of the polyamine pathway lead to a sizable shift in both the molecular and effector profiles of Th17 cells. It is suggested that polyamine metabolism might be a novel therapeutic target in autoimmune disorders by showing that in vivo inhibition of two different enzymes in the pathway alleviates experimental autoimmune encephalomyelitis (EAE) – a murine model for human multiple sclerosis.

Advisor: Yosef, Nir
Essays on Capital Market Implication of Stock Indexing: Price Discovery and Mandatory Reporting Quality

In the first chapter titled “Identifying the Effect of Stock Indexing: Impetus or Impediment to Arbitrage and Price Discovery?”, with Panos N. Patatoukas, we validate Russell reconstitution as a quasi-natural experimental setting and explore securities lending market dynamics and price discovery process at both the upper and lower cutoffs./nThe rise of stock indexing has raised concerns that index investing impedes arbitrage and degrades price discovery. This paper uses Russell’s reconstitution to identify the causal effect of index investing on information arbitrage and price discovery. While index investing has no discernible effect on the ability of arbitrageurs to trade and impound news into the prices of large- and mid-cap stocks, we find that index investing increases the speed of price adjustment to news for micro-cap stocks. Our causal evidence identifies the relaxation of arbitrage constraints as a mechanism through which indexing facilitates informed trading for more arbitrage-constrained micro-cap stocks./nIn the second chapter titled “Does Index Membership Affect the Quality of Mandatory Financial Report? Evidence from Index Deletions”, I examine the effect of stock indexing on mandatory disclosure quality./nThis paper examines whether stock indexing affects the quality of mandatory financial reports. Using a fuzzy regression discontinuity design at the lower cutoff of the Russell 2000 Index, I find that small-cap firms moving out of the Russell 2000 exhibit more errors in annual and quarterly financial statement numbers, reduce the amount of textual disclosure, and increase the ambiguous tone in 10-K filings. On the contrary, mandatory reporting quality does not change following the addition to the Russell 2000. The evidence suggests that index deletion poses a higher informational risk to investors and highlights the positive effect of index membership in ensuring disclosure quality for small-cap firms in a limited information environment.

Advisor: Patatoukas, Panos
Quantum Gravity Beyond Equilibrium

In this thesis, we explore the intersection between relativistic quantum gravity and non-equilibrium physics. We demonstrate a scenario where non-equilibrium physics can provideimportant insights into quantum gravity by non-perturbatively proving a weak gravity con-jecture using entropic considerations. We take a different approach to extending stringtheory to describe scenarios where the universe is not assumed to be static and eternal byapplying the Schwinger-Keldysh technique to Large-N gauge theories. We use the correspon-dence between Large-N gauge theories and string theory to derive a universal structure thatworldsheets must follow out of equilibrium.

Advisor: Horava, Petr
The Transition to Monoculture in the United States Strawberry Industry

This dissertation analyzes the history and evolution of the United States strawberry industry from an economic perspective. Particular emphasis is placed on the location of production, the use of damage control, and the development of capital, elements which I argue gave rise to a system of strawberry monoculture. To do so, I take a multidisciplinary approach and draw on different bodies of literature to address key components of the industry's history, including the economic and biological rationale underlying agents' production choices, how emerging supply chains altered the organization of the industry, and the intransigence of production systems after they have been developed. In Chapters 1 through 3, I provide a cursory overview of the origins of the strawberry industry, its production trends, key innovations, and its status leading up to and following the phaseout of the agricultural chemical methyl bromide. I also discuss the literature and methodological background I intend to draw upon; in particular, the evolution of agricultural systems, innovations and the development of new supply chains, and the economic and biological considerations of crop rotation and monoculture. I then introduce a more detailed depiction of strawberries prior to their commercialization, as well as the characteristics of proto-commercial production in the eastern US; this focuses on the confluence of key transportation supply chains and a breakthrough innovation in strawberry varieties, a combination which led to the formation of a full-fledged strawberry industry. I examine the structures that developed in response to this expansion as well as the costs and profits of a representative grower. In Chapters 4 through 7, the focus of the historical narrative shifts from eastern and southern states to California. I provide a brief overview of the practice of fumigation and its development post-1850; in particular, I examine key fumigants and their uses, as well as their drawbacks, as context for the persistence of methyl bromide. I then discuss how California became the undisputed leader in national strawberry production, and how future innovations have been predicated upon the soil conditions provided by methyl bromide fumigation. I then use this contextual framework to construct a theoretical model of agricultural production in which an agent chooses between rotation and a chemical damage control agent. In Chapters 8 and 9, I introduce the changes occurring to strawberry production in the post-war era, including several of the post-war innovations that depended on fumigation. I additionally fit empirical data to models of adoption suggested by economic literature. I conclude with a short overview of lessons derived from the historical narrative, including how key, seemingly immutable characteristics of strawberry production have persisted through the previous two centuries and continue to shape the industry.

Advisor: Zilberman, David
Essays in Entrepreneurship, Venture Capital and Innovation

In chapter 1, I study a dynamic innovation race, in which firms invest to be the first toattain a breakthrough invention. I examine how delays in monitoring firms' investments affect their ability to achieve a coordinated under-investment equilibrium enforced by the threat of elevated investment by rival firms. When monitoring delays are small, equilibrium investment can be considerably delayed, matching the first-best solution under cooperation. Even with significant delays in monitoring, equilibrium investment is below, and firm values are well above, the no-monitoring competitive outcome. As a result, the regulatory goal of transparency can conflict with the goal of encouraging investment in innovation. In addition I study how changing the number of firms in the race can affect the outcome. As the number of firms increases, the incentive to preempt escalates, and coordinated effort boundaries decline, as does the maximum delay time in which the first best can be achieved with coordination./nIn chapter 2, I study the contracting problem between investors (limited partners or LPs) and venture capitalists ( general partners or GPs) . In real world, GPs are sometimes paid on a deal-by-deal basis and other times on a whole-portfolio basis. When is one method of payment better than the other? I develop a model to see how the method of compensation's payment can affect the behavior of general partners (GP) in a limited partnership agreement (LPA). I show that when assets (projects or firms) are highly correlated or when GPs have low reputation, whole-portfolio contracting is superior to deal-by-deal contracting. In this case, by bundling payouts together, whole- portfolio contracting enhances incentives for GPs to exert effort. Therefore, it is better suited to alleviate the moral hazard problem which is stronger than the adverse selection problem in the case of high correlation of assets or low reputation of GPs. In contrast, for low correlation of assets or high reputation of GPs, information asymmetry concerns dominate and deal-by-deal contracts become optimal, as they can efficiently weed out bad projects one by one. These results shed light on recent empirical findings on the relationship between investors and venture capitalists.

Advisor: Manso, Gustavo
A relative version of Rochlin’s theorem

Rochlin proved that a closed 4-dimensional connected smooth oriented manifold $X^4$ with vanishing second Stiefel-Whitney class has signature $\sigma(X)$ divisible by 16. This was generalized by Kervaire and Milnor to the statement that if $\xi \in H_2(X;\mathbb{Z})$ is an integral lift of an element in $H_2(X; \mathbb{Z}/2\mathbb{Z})$ that is dual to $w_2(X)$, and if $\xi$ can be represented by an embedded sphere in $X$, then the self-intersection number $\xi^2$ is divisible by 16. This was subsequently generalized further by Rochlin and various alternative proofs of this result where given by Freedman and Kirby, Matsumoto, and Kirby./nWe give further generalizations of this result concerning 4-manifolds with boundary. Given a smooth compact orientable four manifold $X^4$ with integral homology sphere boundary and a connected orientable characteristic surface with connected boundary $F^2$ properly embedded in $X$, we prove a theorem relating the Arf invariant of $\partial F$, and the Arf invariant of $F$, and the Rochlin invariant of $\partial X$. We then proceed to generalize this result to the case where $X$ is a topological compact orientable 4-manifold (which brings in the Kirby-Siebenmann invariant), $\partial F$ is not connected (which brings in the condition of being proper as a link), $F$ is not orientable (which brings in Brown invariants), and finally, where $\partial X$ is an arbitrary 3-manifold (which brings in pin structures). The final result gives a ``combinatorial'' description of the Kirby-Siebenmann invariant of a compact orientable 4-manifold with nonempty boundary.

Advisor: Teichner, Peter
Kirby, Robion C.
Goal-Directed Exploration and Skill Reuse

Reinforcement learning is a powerful paradigm for training agents to acquire complex behaviors, but it assumes that an external reward is provided by the environment. In practice, this task supervision is often hand-crafted by a user, a process that is time-consuming to repeat for every possible task and that makes manual engineering a primary bottleneck for behavior acquisition. This thesis describes how agents can acquire and reuse goal-directed behaviors in a completely self-supervised manner. It discusses challenges that arise when scaling up these methods to complex environments: How can an agent set goals for itself when it does not even know the set of possible states to explore? How does an agent autonomously reward itself for reaching a goal? How can an agent reuse this goal-directed behavior to decompose a new task into easier goal-reaching tasks? This thesis presents methods that I have developed to address these problems and share results that apply the methods to image-based, robot environments.

Advisor: Levine, Sergey
White Musical Mythologies: Modernism and the Ontology of Sound from Paris to New York

This is a history of the idea of presence in modern music. Its opening hypothesis is that, whereas in nineteenth-century contexts the performed presence of music in concert halls inspired critics and scholars to write, during the twentieth century writing began to supersede performed music. My narrative follows a series of modernist composers who sought to intensify the presence of sound in their moment, yet who wound up creating what Jacques Derrida termed a “written being” (l’être écrit) of musical presence, a linguistic double or “written echo” that would henceforth play a central role in how Euro-American art music would be understood, created, and even experienced. I then examine the ethical valence of the composerly bid to produce presence. Each of these composers took cues or appropriated forms of expression from non-European others as they adopted what may be termed an ontological disposition toward sound, believing that sound has a deeper metaphysical reality than what had previously been conveyed in western music. Describing Erik Satie’s fascination with medieval Catholicism (Europe’s pre-modern other) and the unconscious states revealed in occult practices like hypnosis (Chapter One), Edgard Varèse’s creation of a fantasy-primitive Mayan soundscape in his 1933-4 composition, Ecuatorial (Chapter Two), Pierre Boulez’s endeavor to recreate in sonic form the spirit possession rituals that he witnessed during travels to Bahia (Chapter Three), and John Cage’s appropriations of “Eastern” ideas (Chapter Four), I approach these musicians in dialogue with contemporaneous French writers (such as Bergson, Bataille, and Artaud) in a narrative that extends from fin-de-siècle Paris to Derrida’s day. My main contention is that the idea of presence in twentieth century music was always a white mythology: a Euro-American ideal of sonic “purity” and autonomy that privileged “the West” over its others.

Advisor: Smart, Mary Ann
Closing the Age Gap in Voter Turnout: The Promise of Election Reform, And the Rising Threat of Youth Voter Suppression

Young Americans consistently vote at lower rates than older Americans, particularly seniors. What explains this age-turnout gap, and which interventions, if any, can help reduce it?/nMy dissertation argues that voting costs are distributed unequally across age groups, and that this unequal distribution plays a central role in explaining the age-turnout gap. I present empirical evidence that when certain voting costs are alleviated via the introduction of voter registration reforms, youth voting rates disproportionately increase: same-day registration laws boost youth turnout by 3.2 to 7.3 percentage points, and automatic voter registration is associated with a 6.3 percentage-point increase in youth turnout. Older age groups see much smaller effects./nUsing data from an original, nationally representative survey, I show that young Americans face higher voting costs than older age groups. In turn, these higher costs predict lower registration and turnout rates. Compared to seniors, today’s youth are less informed about the voting process and how to research candidates and issues; struggle more to find the time to vote, to plan ahead to vote, and to balance voting with other life tasks; face greater transportation issues and tradeoffs between voting and earning money; have greater difficulty with the parts of voting that cannot be done online; disproportionately think mail voting is a hassle; and are less likely to own the documentation they need to register and vote. When asked directly, youth are significantly more likely than older Americans to say that registration and voting are difficult. After adjusting for race and ethnicity, gender, education, and family income, being young (relative to being a senior) is a large and statistically significant predictor of facing voting costs. I also find that young people are the least-informed of any age group about their state’s policies on same-day registration, early voting, mail voting, and policies around updating voter registration./nConsidering the recent rise in youth-targeted voter suppression, I present data from a randomized controlled survey experiment, which finds that informing young people about efforts to limit their ability to vote does not significantly increase their voting intentions. Notably, it does among youth with a strong sense of age identity—but most young people do not identify especially strongly with their age group. Previously documented backlashes to voter suppression may have been larger because they targeted more cohesive or “important” identity groups. Unless young people begin seeing their age as a more important aspect of their identity, we should not expect youth-targeted suppression to spark the same countermobilization.

Advisor: Lerman, Amy
Energy Efficient Vehicle Dynamics and Powertrain Controls for Connected Plug-in Hybrid Electric Vehicles

Plug-in hybrid electric vehicles (PHEVs) are considered energy efficient and predicted to be the dominant vehicle type near the future, together with pure electric vehicles. For PHEVs, a medium-sized battery allows to save energy by reducing the internal combustion engine (ICE) idling time and running the ICE at a highly efficient operating region. EveryPHEV implements an energy management system that allocates the current power demand requested from the driver or longitudinal controller to the on-board power sources. Although commercial energy management systems are tuned for energy efficiency and drivability for various driving conditions, there is still a signicant margin left to improve energy performance by exploiting forecasts of traffic information, which are delivered to the vehicle using connectivity. In this dissertation, we develop novel energy-efficient predictive control strategies for PHEVs for real-world driving scenarios utilizing connectivity. The proposed strategy also applies to HEVs, although the benets might be limited due to the small-sized battery. We consider the two most occurrent real-world driving scenarios: highway driving and urban driving. For highway scenario, we develop an adaptive cruise controller (ACC) that controls longitudinal motion as well as manages on-board energy sources. Classical ACC controls longitudinal motion of the vehicle as a function of feedback from environmental sensors, which typically does not consider energy performance. The proposed ACC uses the sensors and vehicle-to-cloud connectivity to ensure safety and enhance energy performance by predicting future traffic information. For urban scenario, we consider communication with infrastructure and, in particular, with traffic lights to improve energy performance even further. We show how to design and implement model predictive controllers for both scenarios and explain how to construct a terminal safe set and cost function such that both safety and energy performance improvements can be guaranteed. In both scenarios, we demonstrate 15 ~ 30% energy performance improvements in hardware-in-the-loop and on-road experiments with the proposed control strategies.

Advisor: Borrelli, Francesco