VictorJuiz/thesis huggingface dataset:
Data-Driven Approaches for Robust Signal Plans in Urban Transportation Networks

In urban transportation networks with signalized intersections a robust pre-timed signal plan is a practical alternative to adaptive control strategies, since it has less complexity and an easier implementation process. Recent advances in technology are making data collection at traffic signals economical and data-driven approaches are likely to benefit from the large traffic data. Data-driven approaches are necessary for designing robust timing plans that can satisfy rapid traffic volume fluctuation and demand growth. This dissertation introduces four data-driven approaches for studying and improving traffic conditions at signalized intersections./n/nFirstly, I discuss the development and testing of two algorithms for checking the quality of traffic data and for estimating performance measures at intersections. The first of these algorithms estimates the systematic error of the detector data at signalized intersections by using flow conservation. According to the ground truth data from a real-world network, the algorithm can reduce the error in the data up to 25%. The second algorithm helps in estimating intersection performance measures in real-time by measuring the number of the vehicles in each approach using high resolution(HR) data./n/nAn offset optimization algorithm was developed to adjust signal offsets so as to improve the delay in the system. The performance of three real-world networks using the offsets obtained by the algorithm and those obtained from the widely used Synchro optimization tool, are compared using the VISSIM microscopic simulation model. Simulation results show up to a 30% reduction in the average number of stops and total delay that vehicles experience along the major routes when using the proposed algorithms’ optimized offsets. The fourth algorithm estimates the appropriate switching time between designed timing plans during the day based on the traffic profile of the intersection by using the K-means clustering method./n/nIn conclusion, these four algorithms extract useful information from HR data about traffic at signalized intersections. Moreover, the algorithms assist in designing robust timing plans for satisfying demand fluctuations at signalized intersection. Lastly, simulation results from real-world networks illustrate the significant improvements that the proposed data-driven approaches can make in the control systems at urban transportation networks.

Advisor: Skabardonis, Alexander
Machine Learning Applications to Robot Control

Control of robot manipulators can be greatly improved with the use of velocity and torque feedforward control. However, the effectiveness of feedforward control greatly relies on the accuracy of the model. In this study, kinematics and dynamics analysis is performed on a six axis arm, a Delta2 robot, and a Delta3 robot. Velocity feedforward calculation is performed using the traditional means of using the kinematics solution for velocity. However, a neural network is used to model the torque feedforward equations. For each of these mechanisms, we first solve the forward and inverse kinematics transformations. We then derive a dynamic model. Later, unlike traditional methods of obtaining the dynamics parameters of the dynamics model, the dynamics model is used to infer dependencies between the input and output variables for neural network torque estimation. The neural network is trained with joint positions, velocities, and accelerations as inputs, and joint torques as outputs. After training is complete, the neural network is used to estimate the feedforward torque effort. Additionally, an investigation is done on the use of neural networks for deriving the inverse kinematics solution of a six axis arm. Although the neural network demonstrated outstanding ability to model complex mathematical equations, the inverse kinematics solution was not accurate enough for practical use.

Advisor: Bajcsy, Ruzena
The Use of Liquid Phase Transmission Electron Microscopy for Quantifying Interactions Between Colloidal Nanoparticles and Visualizing Their Self-Assembled Structures

Abstract/n/nThe Use of Liquid Phase Transmission Electron Microscopy for Quantifying Interactions Between Colloidal Nanoparticles and Visualizing Their Self-Assembled Structures/nBy/nHoduk Cho/nDoctor of Philosophy in Chemistry/nUniversity of California, Berkeley/nProfessor A. Paul Alivisatos, Chair/nThis dissertation demonstrates the application of liquid phase transmission electron microscopy for quantifying interactions between colloidal nanoparticles and visualizing their self-assembled structures in their native solution state. Over a decade ago, the first liquid cells that could successfully enclose a thin layer of liquid while maintaining compatibility with the high vacuum conditions inside an electron microscope were developed. Subsequent commercialization of this technology by several companies greatly increased its accessibility and the research field has expanded rapidly as a result. The ability to directly visualize real-time nanoscale dynamics in solution has enabled researchers in physics, chemistry, biology, and materials science to investigate previously unexplored scientific phenomena. Thus far, the vast majority of research in this field has made use of the highly perturbative effect of the electron beam to initiate the dynamic process under study. Although this approach has yielded fruitful knowledge and insights, it has not been straightforward to extrapolate the conclusions formed from these studies to experiments conducted outside of the electron microscope. The effects of electron beam irradiation are still poorly understood, and ways to counteract them are limited. A more widespread application of liquid phase transmission electron microscopy would only be realized if the influence of the electron beam were well-known and could be tuned in a predictable manner. By understanding and controlling the effects of the electron beam on the encapsulated specimen during the imaging process, it will be possible to extract information relating to the behavior of colloidal nanoparticles in solution that can be generalizable to experiments carried out in the wet lab./nChapter 1 introduces the basic concepts of nanoparticle self-assembly, interparticle interactions at the nanoscale, DNA-mediated nanoparticle assembly, liquid phase transmission electron microscopy, and radiation-induced effects that accompany electron microscopy imaging in liquid. Chapter 2 illustrates how the individual trajectories of nanoparticles moving in solution, obtained using liquid phase transmission electron microscopy, can be utilized for quantitative analysis of their interparticle interactions. Chapter 3 describes how the damaging effects of electron beam irradiation on DNA-assembled nanoparticles can be mitigated with the use of graphene and its derivatives as biocompatible radical scavengers. Chapter 4 summarizes the seminal findings that are reported in this dissertation and provides a brief outlook for the future.

Advisor: Alivisatos, Armand P
Biomimetic “Nacre-Like”, Metal-Compliant-Phase Ceramics Produced via Coextrusion

Coextrusion is shown to be a viable processing route for the fabrication of bioinspired ceramic materials that exhibit improved damage tolerance. This provides one of the few examples of the synthesis of "nacre-like" ceramic hybrid structures with “brick-and-mortar” architectures using a method that includes a metallic “mortar” (i.e., the compliant phase) during the entire fabrication process, instead of infiltrating it into a pre-fabricated ceramic scaffold. Detailed examination shows how manipulation of such processing can lead to improved mechanical performance in the resulting biomimetic ceramics by obtaining a model high volume fraction (~90 vol. %) ceramic with a brick-and-mortar architecture containing a metallic compliant phase. Specifically, brick-and-mortar alumina hybrid structures were synthesized containing small volume fractions (<10 vol. %) of nickel (Al2O3/Ni) which were made by the coextrusion of alumina and nickel oxide in a thermoplastic (polyethylene-ethyl acrylate) suspension. Furthermore the contributions from brick morphology as well as size are examined to extrapolate on the mechanical properties of idealized metal compliant phase brick-and-mortar structures. Flexural strength and crack-initiation fracture toughness values were used to compare the performance of various ceramic architectures, with full crack-growth resistance curves (R-curves) measured and compared to similar bioinspired ceramics for the most promising alumina structures. These mechanical tests were performed as a function of temperature to explore the evolution of toughening contributions of the mortar and structure as it relates to changes in the mortar plasticity and to consider the viability of these structures in elevated temperature environments. It was found that even though these structures are significantly coarser than those made with other processing methods, they still exhibit comparable crack-growth resistance despite their lower strength. Toughening was induced by marked crack deflection as the crack path followed the metallic mortar phase coupled with significant crack bridging and brick pull-out in the image of the toughening mechanisms seen in nacre. These effects were shown to be more pronounced as brick size reduced closer to natural structures and additionally it was observed that crack growth resistance improved as a function of increasing temperature due to greater ductility in the metallic mortar.

Advisor: Ritchie, Robert O
New Criticism Int.: The Close Reader in the U.S., Brazil, and Israel

Playing on John Crowe Ransom’s iconic “Criticism Inc.,” my dissertation, New Criticism Int.: The Close Reader in the U.S., Brazil and Israel, reveals the as yet unexplored global circulation of the North American theory of New Criticism, and its influence on international reading practices, literary production, and national identity construction. The dissertation follows the theory as it travels from North America to Brazil and Israel, where New Criticism combines with regional trends to provoke a radical institutional and cultural change. This new map provides a fresh model for understanding close reading, New Criticism’s key practice, which remains the prevailing method of critical reading taught in American institutions and abroad. The New Critics, it is usually assumed, believed that close reading involved a self-enclosed aesthetic object and a detached reader who contemplates the text but takes no part in constructing its meaning. New Criticism Int. demonstrates by contrast that the New Critics viewed the reader as an active participant in the creation of the text as an autonomous object. Specifically, they posited the reader’s mental work of attention as what allows the text to maintain its illusion of independence from the consumer. Consequently, the New Critics were highly invested in disciplining their readers into attention, and developed a sophisticated theory of the reader’s mind, which my study unpacks. Against this backdrop, close reading emerges as a pedagogical tool, which—though initially designed to serve aesthetic goals—was frequently deployed by the New Critics to serve political purposes, such as contouring the reader’s national identity. In other instances, the manipulation of attention was marshaled to open up ethical potentials, cultivating the reader’s receptivity to alterity./nMy dissertation further demonstrates the vital role New Criticism played in the rise of experimental modernist literary forms and in processes of canonization within the U.S., Brazil and Israel. Though the New Critics presented close reading as suitable for any literary text, this method was in effect devised to fit specific works, which these thinkers deemed conducive to attention and therefore helped canonize. Such is the case, for example, with the oeuvre of William Faulkner in the North American context. On the other hand, New Criticism also generated literary counter-reactions to the imperative of attentive reading in the form of satires that mock the close reader, or literary texts fashioned to incite inattentive readerly modes. In this vein, the Brazilian Clarice Lispector exhausts her readers into distraction, and the Israeli Yehuda Amichai concatenates his metaphors to disturb a linear line of thought. New Criticism Int. thus offers a new international genealogy of New Criticism, and links it to global dynamics of literary production.

Advisor: Kronfeld, Chana
The Yeoman Myth: How Land Access Dilemmas Confound Beginning Farmer Aspirations

An aging domestic farmer population and depreciating rural sector provokes “good food” activists and policy makers alike to ask, “Who will farm?” One proposal is the aspirational narrative of beginning farmers, where a new generation eschews urban ambitions for a rural life based around environmental stewardship and food systems transformation. This ideal replicates a classic American imaginary: the self-made yeoman farmer as the foundation of society. In doing so, the beginning farmer movement demonstrates a critical blind spot: How will these new farmers get onto the land? Learning from farmers seeking to fulfill this new agrarian dream in California, this dissertation shows how the problem of land access threatens to dead-end the aspirations of the beginning farmer movement./nFirst, I examine how sociocultural and relational constraints impede land access for former immigrant farmworkers aspiring to independent farming in California’s Central Coast region. Here, I argue that landlord–tenant farmer dynamics dominate and thus complicate beginning farmer narratives. Then, I analyze the flagship federal support program for beginning farmers, the Beginning Farmer and Rancher Development Program (BFRDP). Analysis of the BFRDP’s funding history and discourse reveals a “knowledge deficit” based program focused on the technical rather than the structural aspects of beginning farming. This is contrasted with qualitative analysis of beginning farmer experiences in California’s Central Coast region. The discrepancies between the farmer experiences and the national structure of the BFRDP program ultimately reveal a policy mismatch between the needs of beginning farmers and the programs intended to support them. Finally, searching for methods to re-envision the standard beginning farmer narratives, I explore how web-mapping tools may attend to the entrenched problems of land access. Land access problems are found to be inherently spatial, opening the possibility of mapping interventions. I describe the development of the Farmland Monitoring Project (FMP), a web-mapping framework that interrogates multiple elements of the land access barrier. The reflection-in-practice of the FMP helps explore the juncture between critical GIS and beginning farmer land access dilemmas./nIn summary, I argue that the antiquated yeoman myth limits the transformative potential of beginning farmer aspirations. I offer suggestions for how to escape such a narrow narrative construction. In principle, without structural attention to land redistribution and access, the ideal of the new farmer will remain a niche phenomenon.

Advisor: Iles, Alastair
Next Generation Datacenter Architecture

Modern datacenters are the foundation of large scale Internet services, such as search engines, cloud computing and social networks. In this thesis, I will investigate the new challenges in building and managing large scale datacenters. Specifically, I will show trends and challenges in the software stack, the hardware stack and the network stack of modern datacenters, and propose new approaches to cope with these challenges./nIn the software stack, there is a movement to serverless computing where cloud customers can write short-lived functions to run their workloads in the cloud without the hassle of managing servers. Yet the storage stack has not changed to accommodate serverless workloads. We build a storage system called Savanna that significantly improves the serverless applications performance. In the hardware stack, with the end of Moore's Law, researchers are proposing disaggregated datacenters with pools of standalone resource blades. These resource blades are directly connected by the network fabric, and I will present the requirements of building such a network fabric. Lastly, in the network stack, new congestion control algorithms are proposed (e.g. pFabric) to reduce the flow completion time. However, these algorithms require specialized hardware to achieve desirable performance. I designed pHost, a simple end-host based congestion control scheme that has comparable performance with pFabric without any specialized hardware support.

Advisor: Ratnasamy, Sylvia
Shenker, Scott
Transition Metal-Catalyzed Enantioselective Silylation of C–H bonds: Reaction Development and Mechanistic Studies

The following dissertation discusses the development of catalytic enantioselective silylation of aryl, cyclopropyl and unactivated aliphatic C–H bonds. This work also includes in-depth studies that reveal the mechanism of the enantioselective silylation and the origin of enantioselectivity./nChapter 1 reviews transition metal-catalyzed reactions that functionalize C–H bonds with an emphasis on enantioselective transformations. This review describes the representative strategies of C–H bond functionalization to obtain site-selectivity. Discussions on the development of enantioselective functionalizations of C–H bonds with representative examples follow./nChapter 2 discusses the development of rhodium-catalyzed enantioselecitve silylation of aryl C–H bonds. Hydrosilyl ethers that are formed in situ by hydrosilylation of benzophenone or its derivatives undergo enantioselective C−H silylation in the presence of a rhodium catalyst. Enantioenriched benzoxasilole products from the silylation process undergo a range of transformations to form C−C, C−O, C−I, or C−Br bonds without erosion of enantiomeric excess./nChapter 3 discusses experimental and theoretical studies on the mechanism of rhodium-catalyzed enantioselective silylation of aryl C−H bonds. The identity of the resting states of the catalyst, the kinetic data, and the results of DFT calculations provide detailed insights into the mechanism of intramolecular enantioselective silylation of aryl C−H bonds and the origin of enantioselectivity./nChapter 4 discusses the development of rhodium-catalyzed enantioselecitve silylation of cyclopropyl C–H bonds. Hydrosilyl ethers, generated in situ by the dehydrogenative silylation of cyclopropylmethanols with diethylsilane, undergo enantioselective silylation of cyclopropyl C–H bonds in the presence of a rhodium catalyst. The resulting enantioenriched oxasilolanes are suitable substrates for the Tamao–Fleming oxidation to form cyclopropanols with conservation of the ee value from the C–H silylation./nChapter 5 discusses the development of iridium-catalyzed silylation of unactivated sp3 C–H bonds of amines. The introduction of silylmethyl group on a secondary amine allows a site-selective functionalization of β-C–H bonds of amines to form silapyrrolidines. Development of both non-enantioselective and enantioselective catalysts is described. The silapyrrolidne product serves as a precursor to 1,2-amino alcohols by the oxidation of the silapyrrolidines, leading to an overall site-selective, and even enantioselective, oxidation of amines at the β-C–H bonds.

Advisor: Hartwig, John F
Evaluating Funding Mechanisms for Natural Resource Conservation

The dissertation is composed of three papers. The first paper explored the history of public investment in natural resource conservation in California. First, the paper focused on the history of state trust lands and cost-share programs, and then discussed the costs and benefits of state issued bonds for natural resource protection. Finally, the paper highlighted new opportunities for funding through tax and fee mechanisms. The paper evaluated these public investment tools and discussed the future of natural resource conservation funding in California./nThe second paper is based on a study conducted to understand how a sales tax affected consumers and producers in California’s lumber market. Tax incidence theory was used to analyze the effect of the tax policy on prices and social welfare. The study analyzed the effect of the lumber tax using a theoretical lumber market model. A partial equilibrium model was used to examine the burden of the tax, ignoring the effects on other markets. This framework determined if the burden of the tax was primarily borne by consumers or producers. The study found that the tax burden fell on the consumers, given the inelastic nature of the lumber market./nThe final paper explored examples of privatization of public land management as well as the recent trend of private investments in natural resource conservation. A case study was examined for managing state parks by private interests highlighting the funding crisis with California’s state parks. The paper also investigated the increase in private investment in conservation over the last few years, focused on mitigation banks, innovative private finance, and environmental impact bonds. The goal was to provide the costs and benefits of privatization of natural resource management and conservation.

Advisor: Gilless, J. Keith
in situ Deformation Studies with Scanning Nanobeam Electron Diffraction

In this dissertation, experimental methods and data processing techniques are developed for nanobeam electron diffraction and applied to both crystalline and amorphous materials. Nanobeam electron diffraction is a technique in which a small electron probe is used to acquire diffraction patterns as the beam is rastered across the sample. We develop methods to use nanobeam electron diffraction during in situ deformation in the scanning transmission electron microscope. First, we describe the sample preparation methods used to create samples with the correct geometry for in situ experimentation. We compare and contrast in situ deformation techniques, including holders and experimental data obtained. We then develop and benchmark variations on cross-correlation algorithms for nanobeam electron diffraction strain mapping on simulated and real data. We find that Sobel filtered cross-correlation and "hybrid" correlation minimize the amount of error when diffraction patterns have uneven illumination. We also show that binning can reduce error when signal to noise is low in the diffraction patterns. We use this result to analyze in situ nanobeam electron diffraction strain mapping on a sample of 321 stainless steel being deformed in tension. We observe the motion of the first dislocation in a planar slip band, and measure the resulting lattice expansion in situ. This result is the first direct confirmation of such phenomena, and is theorized to be the reason why planar as opposed to wavy slip occurs. We then develop methodology to measure both strain and local order in amorphous materials, and demonstrate the technique on Cu46Zr46Al8 bulk metallic glass. We observe strains in excess of 2% before the sample fractures along a shear band, small amounts of plasticity, as well as a decrease in local order at high strains in areas where the sample fractured. This is supported by molecular dynamics simulations, and experimentally supports the shear transformation zone model of metallic glass deformation. As a whole, this dissertation presents method developments in in situ nanobeam electron diffraction for both crystalline and amorphous samples, as well as practical results of interest to the materials science community.

Advisor: Minor, Andrew M