VictorJuiz/thesis huggingface dataset:
Guest Worker Programs and Immigration

This thesis takes a historical and comparative approach and examines three countries’ approaches to guest workers and each country’s respective immigration policy. The countries considered are all among the countries currently considering immigration reform. This thesis begins with an explanation of how a guest worker program is part of immigration policy and defines what a guest worker program looks like from the perspective of citizens within a country as well as the migrant who crosses borders for purposes of work. It then shifts to finer analyses of the Bracero program in the United States, the Gastarbeiter programs in Germany and the Seasonal Agricultural Workers Program (SAWP) in Canada, to show how guest worker programs have been implemented thus far. These chapters’ accounts on immigration policy span the past seventy years.
The main metrics for assessing the programs are illegal immigration, adverse effect on citizens, economic improvement for the immigrants, and public opinion. These metrics are both used to measure how effective each program was on immigration policy and to understand what factors influenced the terms of that policy. Due to limitations in quantitative data, the focus is on descriptive analyses. This thesis concludes with a policy recommendation regarding a guest worker program based on the historical analyses. The conclusion of the study is that the theoretical model underlying a guest worker program has not worked in practice so significant revisions to the terms of a program would be necessary for it to be effective as immigration policy.

Keywords:  Program in International Relations
Immigration
Guest Workers
Stanford University Program in International Relations
Thesis
Advisor: Padilla Amado
A hardware security application of the nanoelectromechanical relay [electronic resource]

The nanoelectromechanical (NEM) relay is a digital component that offers extremely low sub-threshold swing characteristics and has been studied by researchers in a number of universities including Stanford. Devices with low sub-threshold swing result in circuits with low power dissipation. Not only does a NEM relay gate provide substantially lower sub-threshold swing than a bulk CMOS gate, as feature sizes of these two technologies shrink going forward, the power savings of NEM relay technology vs. CMOS technology widens. Consequently, there has been active research into the feasibility of creating complete digital chips based on NEM relays. Though power savings may be a predominant application for NEM relays, this thesis explores using NEM relays for component level hardware security, a problem that has become serious as reports of chip counterfeiting have increased in recent years along with the real feasibility of successful hardware Trojan attacks. In order to thwart counterfeiters and highly intelligent, well-resourced attackers, security designs must become more sophisticated. The NEM relay is effectively an actuation device. Bias applied to the gate creates an electrostatic force that in turn causes mechanical motion that opens or closes a switch. An enhanced version of the NEM relay has a piezoelectric stack deposited on its cantilever beam with two new contacts connecting to electrodes that sandwich a thin piezoelectric film in the center of the stack. This new device, a piezoelectric NEM relay (PNR), is analyzed using a parallel-plate actuation model, a modified vibration harvester model, a distributed-parameter dynamic model, and finite element method modeling. The models show the natural response of the PNR cantilever beam to a step excitation provides an electrical signal, a damped oscillation whose frequency is structure design dependent, with sufficient duration to serve as a signature of the gate. Modules can be constructed from multiple gates that combine the signatures of each resulting in a composite module signature. Consequently, a legitimate module has a characteristic frequency domain signature that can be monitored. A hierarchal design approach can be used to create a component level device with component signatures. Signatures of a known legitimate component and a test component are compared as part of the screening process that detects corrupted parts. The end result is a digital component that provides a complex frequency domain test signal that can be used as a legitimate component signature to augment standard component test methods. Device security has been described as a continuous cat and mouse game with the forces of good working hard to stay ahead of counterfeiters and attackers. This thesis presents another tool the good forces may employ.

Keywords: Electrical Engineering.
Advisor: Howe Roger Thomas advisor. Thesis advisor
Having the right attitude [electronic resource]

The idea of respect for persons is supposed to play a foundational role in many non-consequentialist moral theories. A prominent Kantian version of these theories says that respect for persons is a matter of responding to the intrinsic value of rational agency and that, accordingly, our basic moral requirements are satisfied by this response to value. I think that this view faces two kinds of problems: it is liable to explanatory circularities, and it is unable to explain how paternalism is generally morally objectionable. My dissertation begins developing an alternative respect-based moral theory that solves these two problems by contrasting with the prominent Kantian theory in two key ways: it starts with an account of how respect for persons shapes our thought and action as an attitude in a certain social practice, rather than with an account of the intrinsic value of rational agency, and it sees respect for persons as a response to someone's authority, rather than to her value.

Keywords: Philosophy.
Advisor: Schapiro Tamar
Bratman Michael advisor. Thesis advisor
Hills David James
Wood Allen W. advisor. Thesis advisor
Hercules at the crossroads of Augustan literature and art [electronic resource]

Two separate and seemingly unrelated myths of Hercules flourished in Rome during the Augustan period: the triumphant Hercules' defeat of the robber-monster Cacus, and the cross-dressed Hercules' enslavement to the Lydian Omphale. The question that this dissertation therefore asks is: why did the Augustan period need not simply one, but two Hercules? Traditional scholarly explanations tie the two myths into post-Actium political propaganda: the Hercules who vanquishes Cacus represents Augustus, while the Hercules in thrall to Omphale represents Antony. I argue instead that the myths address more broadly two separate anxieties about faltering normative power structures in Rome at the end of the first century BCE. The myth of Hercules and Cacus speaks to concerns about political succession and transition, specifically how Augustus and Augustus' Rome fit within the narrative of Roman history. The myth of Hercules and Omphale, on the other hand, answers a growing fear about the status of Roman masculinity in an era that is witnessing the rise of powerful women at home and abroad.

Keywords: Classics.
Advisor: Trimble Jennifer
Barchiesi Alessandro advisor. Thesis advisor
Parker Grant Richard
The hermeneutics of textual hierarchies in the Babylonian Talmud [electronic resource]

In this dissertation I challenge longstanding assumptions regarding the hermeneutical relationships between the various textual layers of the Babylonian Talmud, arguing that inversions of the Talmud's layered hierarchy must not be regarded as aberrant or subversive deviations from a dominant hermeneutical paradigm that is otherwise systematically maintained, but rather must be understood as a key component of the interpretive activity of the creators of the anonymous stratum. Building on a theoretical foundation constructed from observations of canonical textual interpretation more broadly considered, I examine the particular case of the Babylonian Talmud focusing on the ways in which the authors of the anonymous stratum interpret received tradition. By analyzing texts that are constructed around the use of particular repeated terminology, I show how this terminology is employed to create a rhetoric of interpretation that often masks instances in which the anonymous authors assert their own authority over that of their (ostensibly more authoritative) sources. By claiming only to recover the original meaning of statements in received tradition, the anonymous authors are able to rework and even rewrite their canonical sources without threatening the integrity of this corpus, as the authority of the anonymous authors is derived from and contingent upon the continued authority and integrity of received tradition.

Keywords: Religious Studies.
Advisor: Fonrobert Charlotte Elisheva primary advisor. Thesis advisor
Bashir Shahzad
Weitzman Steven
Wimpfheimer Barry S. advisor. Thesis advisor
High quality and effective instruction for young children [electronic resource] : variation by socioeconomic status, race, and language status

By the start of kindergarten, there are already large gaps in achievement between black and Hispanic children and their white peers, between children from lower socioeconomic backgrounds and their higher socioeconomic counterparts, and between dual language learners (DLLs) and their native English-speaking peers. This dissertation examines the degree to which high quality public pre-K and bilingual education in early childhood are likely to narrow achievement gaps and promote faster academic growth trajectories for "at-risk" students. The dissertation is comprised of three papers. The first considers whether there are gaps in the quality of state-funded pre-K experienced among students of different racial, ethnic, socioeconomic, and language backgrounds, and if so, what kinds of state- and classroom-level factors explain these "quality gaps." This paper has implications for whether public pre-K, in its current form, might narrow the achievement gap. For the second and third papers I focus in on one of the four subgroups studied in paper one -- DLLs. In paper two I examine which quality indicators of bilingual pre-K are the strongest predictors of DLLs' academic growth in English, Spanish, and executive functioning skills over time, and whether the predictive validity of these measures varies by DLLs' student backgrounds. Finally, in the third paper I use quasi-experimental methods to examine which specific models of bilingual vs. English-only education in early elementary school predict the best long term academic outcomes for DLLs. I also consider whether these effects vary for Latino versus Chinese DLLs. Across the three papers, I discuss policy implications.

Keywords: Education.
Advisor: Reardon Sean F. primary advisor. Thesis advisor
Goldenberg Claude
Hakuta Kenji advisor. Thesis advisor
Stipek Deborah J.
High-dimensional multivariate regression and reduced rank estimators [electronic resource]

In statistical learning and modeling, when the dimension of the data is higher than the number of samples, the estimation accuracy can be very poor and thus the model can be hard to interpret. One approach to reducing the dimension is based on the assumption that many variables are a nuisance and redundant; consequently, many variable selection methods have been proposed to identify only the most important variables. Another approach to reducing the dimension is factor extraction, which is based on the assumption that the high-dimensional data can be approximately projected on a lower-dimensional space. Factor extraction, such as principal component analysis (PCA) and canonical correlation analysis (CCA), provides a good interpretation of the data, but the dimension of the reduced space (the number of underlying features) is typically not easy to estimate. In the context of regression analysis, where we want to fit a linear model yt = BTxt + et given n observations xi 2 Rp and yi 2 Rq for i = 1; : : : ; n, several important variable selection methods, e.g. lasso-type shrinkage, forward stepwise selection and backward elimination, have been well studied for dimension reduction. However, there are not many theoretical results of these methods for multivariate regression models with stochastic regressors (also called 'stochastic regression models') found in the literature. In this dissertation, we present an effcient algorithm for solving high-dimensional multivariate linear stochastic regression. The motivation comes from modeling and prediction for multivariate time series models in macroeconomics and for linear MIMO (multiple-input and multiple-output) stochastic systems in control theory. By extending the 'orthogonal greedy algorithm' and 'high-dimensional information criterion' for 'weakly sparse' models in Ing and Lai (2011), we can choose a subset of xt and reduce the dimension p to o(n). We can then perform reduced-rank regression of yt on this reduced set of regressors and introduce an information criterion to choose the number of factors and estimate the factors. We provide theoretical results for our algorithm. We carry out simulation studies and an econometric data analysis to evaluate the algorithm.

Keywords: Computational and Mathematical Engineering.
Advisor: Lai T. L. primary advisor. Thesis advisor
Rajaratnam Balakanapathy advisor. Thesis advisor
Saunders Michael A. advisor. Thesis advisor
High-efficiency thin-film crystalline solar cells [electronic resource]

Thin-film high-efficiency crystalline solar cells are expected to play a significant role as a greener, renewable energy source of the future. Such cells have been extensively studied over the past 10 years. Most of this research focused on developing thinner cells to reduce material usage and improving the optical absorption within the thin absorber. Most recently, the active semiconductor layer can be 10 -- 100 times thinner than conventional solar cells by advanced light trapping. However, an improvement in efficiency in thin-film solar cells had not been previously appreciated and is an equally if not more important enhancement of the cells in addition to materials cost saving. This dissertation presents the device physics of thin-film crystalline solar cells and demonstrates the key design principle to achieve higher efficiency by improving two important parameters: open circuit voltage (Voc) and short circuit current (Jsc). The first part of this thesis focuses on achieving high Voc in thin-film c-Si solar cells and demonstrate the voltage enhancement in thin-film Si solar cells in both theoretical simulation and experimental demonstration. Theoretically, thin cells can significantly increase the carrier concentration by confining photo-carriers into a smaller active region and decrease the recombination by reducing the volume of the active region. This results in higher Voc and efficiency. Experimentally, the first Voc enhancement in thin-film solar cells is demonstrated. The 5 µm thick Si cell achieved a Voc of 649 mV, which is superior to the Voc of any other thin-film (sub-25-µm) Si solar cells reported to date. To further improve efficiency, a carrier selective contact of TiO2/Si was developed to reduce the high carrier recombination at the metal contacts associated with the high carrier centration in thin films. Such a contact demonstrates a contact recombination reduction of 33% and a Voc enhancement of 10 mV compared to a conventional metal contact. The second part mainly discusses high Jsc by applying nanoscale light trapping structures to thin-film c-Si and III-V solar cells. Given the challenges in obtaining low surface recombination and high efficiency in nanostructured solar cells, we demonstrated a nanowindow solar cell design with dielectric or wide bandgap semiconductor material that can overcome these challenges. A SiNx nanostructured dielectric layer can provide both light tapping and surface passivation for Si. A thin Si film with such SiNx layer exhibits < 5% reflection over a wide spectra and angular range. The last part focuses on absorption improvement in nanostructured GaAs thin-film solar cells. Applying front-side nanostructures significantly increases optical absorption in a 300 nm thick active region. This results in over 95% absorption from visible light to near infrared light, and enables GaAs solar cells with only 300 nm thick absorber.

Keywords: Electrical Engineering.
Advisor: Harris J. S. (James Stewart)
Cui Yi
Fan Shanhui
High-energy lithium-sulfur batteries [electronic resource] : from theoretical understanding to materials design

Rechargeable lithium-ion batteries have transformed the world of portable electronics and consumer devices today, but their specific energy and cycle life remain insufficient for many emerging, modern-day applications such as electric vehicles and grid energy storage. Lithium-sulfur (Li-S) batteries represent a very promising technology for these applications because their theoretical specific energy is about 7 times that of lithium-ion batteries today. However, the challenges of S and Li2S cathodes include: (1) the formation of intermediate lithium polysulfide species which dissolve into the electrolyte during cycling and (2) the low electronic conductivity of S and Li2S. Thus, there is an urgent need for novel encapsulation materials and morphologies for these cathodes that can effectively confine the polysulfide species and facilitate electronic conduction. In this thesis, I will present my work on developing high-energy Li-S batteries, from theoretical understanding to materials design. First, I will present results from theoretical ab initio simulations which enable the systematic screening of promising encapsulation materials. Next, I will present four different designs of S and Li2S cathodes. The first design is that of S-TiO2 yolk-shell nanostructures, which uses oxygen-rich TiO2 as the encapsulation material. The novelty of this yolk-shell cathode lies in the precise engineering of internal void space to accommodate the volumetric expansion of S during lithiation, enabling long cycle life of 1,000 cycles to be achieved. The second and third designs: Li2S-graphene oxide and Li2S-polypyrrole composite structures, use oxygen-rich and nitrogen-rich materials respectively to encapsulate fully-lithiated and fully-expanded Li2S cathodes. Using these cathodes, we demonstrate high specific capacity and stable cycling performance over hundreds of cycles. The fourth design: Li2S-TiS2 core-shell nanostructures, uses highly-conductive and sulfur-rich TiS2 as an effective 2D encapsulation material. This cathode not only exhibits high rate capability of 4C (fast charge/discharge in 15 min), but also high areal capacity of 3.0 mAh/cm2, both of which are on par with commercial standards today. These works pave the way for the future development of high-performance and long-lasting rechargeable batteries.

Keywords: Materials Science and Engineering.
Advisor: Cui Yi
Cui Bianxiao advisor. Thesis advisor
Melosh Nicholas A. advisor. Thesis advisor
High-resolution SAR A/D converters with loop-embedded input buffer [electronic resource]

Successive-approximation-register (SAR) analog-to-digital converters (ADCs) have generated a significant amount of interest in the past several years. While most of the recent literature focuses on low-to-moderate resolution designs (8-10 bits), we are now beginning to see significant advancements in the high-resolution space, targeting ≥14 bits at 10-100 MS/s. Traditionally, this performance range has been dominated by pipelined and delta-sigma architectures. However, several applications in high-speed control and interference cancellation require low laten-cy and this is where the SAR topology becomes attractive. While several SAR ADCs have demonstrated efficient digitization at high speed and resolution, the difficulty of driving a large sampling capacitor with high accuracy in a short sam-pling window is an important challenge in the System-on-a-Chip (SoC) integration of such ADCs that is often ignored in the literature. The work of this dissertation led to the design of a 14-bit 35 MS/s SAR ADC in 40 nm CMOS with a loop-embedded input buffer that consumes only 23% of the total ADC power. The buffer uses a source follower topology whose nonline-arities are cancelled by the SAR algorithm, allowing us to achieve 99 dB spurious-free dynamic range (SFDR) despite the small amount of invested power. That approach made it possible to reduce the input capacitance of the ADC by a factor of eighteen, easing the drive requirements substantially and resulting in the highest reported SFDR for SAR ADCs with a sampling speed greater than 20 MS/s. Additionally, a second SAR ADC design (30 MS/s) based on a noise filter gear-shifting concept is introduced. Using a comparator with time varying noise performance, this ADC achieves a state-of-the-art figure of merit (FOM) of 161.6 dB and a peak signal to noise-plus-distortion ratio (SNDR) of 77 dB, which is the highest reported value for SAR ADCs with a sampling frequency above 20 MHz.

Keywords: Electrical Engineering.
Advisor: Murmann Boris primary advisor. Thesis advisor
Lee Thomas
Wooley Bruce A.
High-sensitivity diaphragm-based fiber optic acoustic sensors and applications [electronic resource]

Acoustic sensors are used for applications in multiple disciplines, including oil and gas extraction, medical devices (magnetic resonance and acoustic/ultrasonic imaging), underwater communications, seismic research, monitoring large structures, and surveillance. Performance requirements vary greatly, but in general the sensors are expected to have a fairly low minimum detectable pressure (MDP), as low as 10 µPa/√Hz in some cases, a wide bandwidth (hundreds of Hz to a few kHz is typical), and a high dynamic range (60 dB in pressure is common). In the first half of this thesis, I present a highly sensitive fiber optic acoustic sensor that meets these requirements by utilizing a high-reflectivity photonic-crystal diaphragm 450 nm thick to convert the incident acoustic or ultrasonic pressure into a mechanical vibration. The diaphragm is placed ~30 µm from the reflective end of a single-mode fiber to form a miniature Fabry Perot (FP) interferometer, which converts this vibration into an optical readout. Thanks to the high compliance of the diaphragm, this sensor exhibits an extremely low MDP of ~2.6 µPa/√Hz over 1--30 kHz, the lowest value reported in the literature. This sensor has recently been used as a hydrophone to listen to the very weak sound generated by the beating of a small number of heart cells, of critical interest for cell sorting and stem-cell research. When used as a force sensor, this sensor was capable of detecting a force as low as 1.3 pN/√Hz in a laboratory environment. In a quieter environment, the minimum detectable force is predicted to be only ~76 fN/√Hz, which is lower than conventional room-temperature AFM-based force sensors. Additionally, a theoretical model based on a finite element analysis was developed to show that this sensor also operates at ultrasonic frequencies and predict its sensitivity dependence on frequency. Measurements of its sensitivity at 72 kHz and 1.025 MHz were perform to demonstrate this potential. In the second half of the thesis, I discuss a low-noise, compact fiber acoustic sensor that implements a novel transducer design, namely a microfabricated silicon diaphragm with a π/2 phase step combined to a single-mode fiber to form a simple two-wave interferometric sensor head. Compared to the FP sensor, this device has a similar strain resolution, it operates over a broad range of wavelengths (~±150 nm instead of ~±1 nm), and both its microfabrication and assembly are simpler. A prototype is reported with an average MDP as low as 5.4 µPa/√Hz between 1 kHz and 30 kHz, in agreement with a theoretical model.

Keywords: Electrical Engineering.
Advisor: Digonnet Michel J. F. primary advisor. Thesis advisor
Fan Shanhui
Solgaard Olav advisor. Thesis advisor