VictorJuiz/thesis huggingface dataset:
Economic adaptation of immigrants [electronic resource] : a comparative approach

Previous studies on the effects of the context of reception on immigrant economic attainment have generally relied on information from detailed case studies. Focusing simultaneously on the characteristics of immigrant groups and the receiving society, these studies provided valuable information on the experiences of immigrants. However, they produced strikingly different accounts of the dimensions of the context that affect labor market attainment. Defining group membership by the country of birth and using multilevel modeling, I address this problem by constructing a comprehensive and systematic account of the factors affecting immigrant integration. I use data from the 2000 U.S. Census, the 2001 Canadian Census, and the New Immigrant Survey in constructing a model that explains a substantial portion of the variance in assimilation across groups. Specifically, it explains 79% of the group-level variance in earnings upon entry to the U.S. and 61% of the group-level variance in post-migration earnings growth. The model allows me to asses whether integration is shaped mainly by ethnic community resources or by external factors. Results show that ethnic community resources are more important in shaping patterns of incorporation than external conditions. The prominent ethnic community factors identified in this research are group socioeconomic advantage and ethnic concentration. However, I show that, among immigrants, the effects of ethnic community resources on earnings growth and the college wage premium are smaller in the Canadian context due to the combined effects of the differences between the countries in integration and immigration policy.I supplement these findings with a description of those groups with especially unfavorable prospects for earnings advancement, allowing me to contribute to the long-standing debate in immigration literature about the reasons for group differences in economic integration. Specifically, immigrants from certain Latin American and South East Asian countries remain economically vulnerable due to limited relative levels of both initial earnings and earnings growth. I explain the dismal integration prospects of immigrants from those groups by highlighting their disadvantages relative to immigrants from other groups in terms of socioeconomic group location and social distance.

Keywords: Sociology.
Advisor: Grusky David B. primary advisor. Thesis advisor
England Paula advisor. Thesis advisor
Snipp C. Matthew advisor. Thesis advisor
Effective scheduling algorithms for service and computing systems [electronic resource]

A number of dynamic stochastic optimization problems of current interest are difficult to solve from both a practical as well as theoretical perspective. These problems are often said to suffer from the 'curse of dimensionality'. Unfortunately, there are few, if any, general methodologies to address these high dimensional optimization problems; such problems tend to be considered on a case-by-case basis. This is in stark contrast to deterministic optimization, wherein there exists techniques for large well-studied families of tractable problems such as convex optimization for continuous problems and submodular optimization over matroids for combinatorial problems. This thesis takes a first step towards constructing such a framework for high dimensional stochastic optimization problems. The main approaches focus on reducing the time horizon over which to optimize and/or making systematic modeling reductions. The scheduling problems presented in this thesis fall under a broad, general class of dynamic stochastic optimization problems whose objectives can be classified as either profit maximization, cost minimization, or a tradeoff between cost and delay minimization. This thesis presents effective, near optimal solutions to a number of hard scheduling problems which have received considerable attention in their own right including, but not limited to, parallel server queues, multimedia broadcast scheduling, product line design, the Adwords assignment problem, and hospital Intensive Care Unit Scheduling. The focus of this thesis is on evaluating the performance of myopic and myopic-like heuristics. This thesis presents a general framework in which to consider a number of dynamic optimization problems. Problems which can be cast in this framework will inherit the performance guarantees of the presented simple, yet effective, heuristic policies.

Keywords: Electrical Engineering
Advisor: Bambos Nicholas primary advisor. Thesis advisor
Apostolopoulos John G. advisor. Thesis advisor
Glynn Peter W. advisor. Thesis advisor
Essays on consumer credit markets [electronic resource]

This dissertation studies the organization of consumer credit markets using a rich and novel dataset from a large subprime auto lender. Its primary goal is to develop empirical methods for analyzing markets with asymmetric information and to use these methods to better understand the behavior of subprime borrowers and lenders. The first chapter quantifies the importance of adverse selection and moral hazard in the subprime auto loan market and shows how different loan contract terms serve to mitigate these distinct information problems. The second chapter examines the impact of centralized credit scoring on lending outcomes, including the distribution of performance across dealerships within the firm. The third chapter studies borrower repayment behavior and quantifies the impact of ex post moral hazard on interest rates and the costs of default. Collectively, the three chapters provide a better understanding of the functioning of markets for subprime credit in the U.S. They also provide unique empirical evidence on the importance of asymmetric information and the value of screening, monitoring, and contract design in consumer credit markets in general.

Keywords: Economics.
Advisor: Einav Liran primary advisor. Thesis advisor
Levin Jonathan D. (Jonathan David)
Bresnahan Timothy F. advisor. Thesis advisor
Fast photoconductive materials for wideband A/D conversion and monolithic integration with CMOS [electronic resource]

All-electronic analog-to-digital converter (ADC) performance is limited by low input bandwidth and high aperture uncertainty. To benefit from the bandwidth and timing accuracy advantages of photonic devices, we investigated a photoconductive-sampling-based photonic A/D conversion system utilizing low-temperature-grown GaAs (LT-GaAs) metal-semiconductor-metal (MSM) photoconductive switches which were flip-chip-bonded with silicon-CMOS ADCs and demonstrated a two-channel prototype system with ~ 3.5 effective-number-of-bits of resolution over an input bandwidth up to 40 GHz and an estimated sampling jitter of less than 80 fs. We studied three material systems targeting the high-speed photoconductive switch application. First, for LT-GaAs films grown on GaAs substrates, we significantly improved the MSM switch performance by systematic optimization of LT-film growth and annealing conditions according to design-of-experiments (DOE) principles. The full-width at half-maximum switching window characterized by electro-optic sampling is ~ 2 ps. To enable monolithic integration of GaAs devices with finished Si IC chips, we studied low temperature growth of GaAs films, both on Si substrates and on SiO2 films. All the experiments, including film growth, annealing and device processing, were performed at temperatures safe for completed IC chips with final metallization and passivation layers. Testing results showed that the switch performance was comparable to or exceeded the reference LT-GaAs switches made on GaAs wafers which were used to fabricate the prototype ADC system. As a final proof of concept, we successfully integrated polycrystalline GaAs switches monolithically on a completely fabricated CMOS amplifier and achieved a functional optical receiver without modifying the underlying Si circuit performance. The beauty of this approach is its simplicity, minimum fabrication disturbance and greater applicability into other areas. We believe this to be the first successful demonstration of monolithic integration of GaAs devices on a fully completed Si chip, and most importantly, demonstrating fully functional and un-degraded performance.

Keywords: Materials Science and Engineering
Advisor: Harris J. S. (James Stewart)
Miller D. A. B. advisor. Thesis advisor
Nix William D. advisor. Thesis advisor
From calcium channels to autism [electronic resource] : effects of the Timothy Syndrome mutation in CaV1.2 on neuronal development

L-type voltage-gated calcium channels (LTCs) play a key role in neuronal development by activating signalling pathways that regulate neuronal gene expression and morphology. A point mutation in the LTC CaV1.2, which blocks voltage-dependent inactivation (VDI), causes autism in Timothy Syndrome (TS) patients. While it is known how VDI influences the current through LTCs, it is not known how alterations in VDI affect the signaling function of CaV1.2 in neurons and ultimately cause developmental defects that lead to autism. Here I show that expression of CaV1.2 channels containing the TS mutation (TS-CaV1.2) inhibits CRE-dependent transcription and causes dendrite retraction and reduced dendrite branching in cortical neurons. I found that expression of TS-CaV1.2 leads to increased calcium influx in neurons and that this increase in intracellular calcium concentrations was in part responsible for the ability of TS-CaV1.2 channels to inhibit CREB. Surprisingly, however, I found that TS-CaV1.2 causes dendritic retraction independently of Ca2+ influx through the channel suggesting that the voltage-dependent conformational changes associated with VDI play an important and unexpected role in CaV1.2 signalling. In addition, I found that TS-CaV1.2 causes dendrite retraction by activating the RhoA signalling pathway. I found that changes in the interaction of the small GTP-binding protein Gem with the channel beta subunit play a critical role in mediating the activation of RhoA by TS-CaV1.2. These results provide new insight into how LTCs are coupled to cytoskeletal signalling pathways in neurons and shed light on the molecular mechanisms underlying the generation of TS and other Autism Spectrum Disorders.

Advisor: Dolmetsch Ricardo E. primary advisor. Thesis advisor
Garner Craig advisor. Thesis advisor
Lewis Richard (Richard Sheridan) advisor. Thesis advisor
Luo Liqun
GPU parallel processing for fast robotic perception [electronic resource]

In this thesis we detail how we built GPU-executed versions of two modern computer vision applications: one a visual servoing algorithm (to control a robotic arm with visual feedback) and the other a sliding-window object detector (to recognize instances of an object class in an image). Starting from slow reference solutions for both algorithms, our goal was to achieve as close to real-time speeds as possible so that these state-of-the-art algorithms could be incorporated onto a mobile robotics platform. We used general-purpose computing on graphics processing units (GPGPU) to accelerate the programs as this strategy has already been used to achieve large speed-ups (of factors of ten to a hundred) on other complex problems. We furthermore developed our applications with CUDA (Compute Unified Device Architecture), which is a programming interface developed by NVIDIA Corporation to perform GPGPU on their graphics hardware. In this thesis we first give a detailed introduction to CUDA, and then we describe in-depth how we built the GPGPU versions of the two computer vision algorithms. In both cases our goals of real-time execution were achieved, seeing end-to-end speed-ups of around fiftyfold.

Keywords: Electrical Engineering
Advisor: Ng Andrew Y.
Has the Crisis Passed? Assessing the Effectiveness of the Term Auction Facility

A key feature of the ongoing financial crisis has been the dramatic and persistent increase in the spreads between the federal funds rate and longer term inter-bank loans. The Federal Reserve has tried to combat the rise in these spreads by injecting liquidity into the market through the creation of measures such as the Term Auction Facility (TAF). The effectiveness of these measures depends on the causes of increased spreads. Is it the liquidity risk premium that is driving inter-bank rates higher? Or instead, are rates being pushed higher by elevated credit risk premiums resulting from the increased risk of default by banks? Using a no-arbitrage model for defaultable bond pricing, I decompose the inter-bank rate into its liquidity, credit and term risk premiums. I then estimate the effectiveness of the TAF in reducing liquidity premiums and find that it had a moderate effect on spreads, indicating that the liquidity risk premium has been a factor in the inter-bank market. I end with a discussion of the implications this result has on future Fed policy towards lowering spreads in the inter-bank market.

Keywords:  Department of Economics
Stanford Department of Economics
federal funds rate
inter-bank loans
Federal Reserve
Term Auction Facility
liquidity risk premium
credit risk premium
term risk premium
Thesis
Advisor: Taylor John B.
High-fidelity, broadband amplification and filtering for spaceborne instrumentation [electronic resource]

This work presents the first fully integrated analog front-end for satellite-based, wideband plasma wave receivers. To enable the next generation of scientific instruments for comprehensive study of wave particle interactions in the Van Allen radiation belts, it comprises: a programmable-gain, low-noise amplifier for electric-field measurements from 100 Hz to 4 MHz that achieves 90-dB SFDR while consuming less than 2 mW; and, a programmable-bandwidth, sixth-order, anti-aliasing filter predicated on a novel, widely tunable transconductor that offers better than 90-dB odd-harmonic suppression and power-efficient field trimming. Notable contributions of this research include design techniques which assure that both elements not only demonstrate high linearity throughout their wide programming ranges but also maintain their performance well beyond a total absorbed dose of 100 krad(Si) with no latchup for LETs of ~100 MeV-cm^2/mg, despite the intrinsic radiation susceptibilities of the commercial manufacturing process in which they are fabricated. To validate these techniques, extensive baseline, radiation, and burn-in tests have been performed; the corresponding experimental procedures and measured results are also tendered.

Keywords: Electrical Engineering
Advisor: Inan Umran S. primary advisor. Thesis advisor
Dutton Robert W. advisor. Thesis advisor
Linscott Ivan advisor. Thesis advisor
High-resolution diffusion MRI of targeted regions [electronic resource]

Diffusion magnetic resonance imaging (MRI) is an MRI method that provides information about random microscopic motion of water molecules in biological tissues. In addition to offering a higher sensitivity for the diagnosis of white matter diseases such as stroke and multiple sclerosis, and producing connectivity maps of the brain, it is a promising prognostic tool in the assessment and treatment response monitoring of cancer in the body. While high in-plane resolution is desirable for all diffusion MRI applications, it is particularly essential for imaging of small structures. Unfortunately, the performance of diffusion MRI techniques is often hindered by a variety of factors including susceptibility variations, field inhomogeneities and bulk physiologic motion. This thesis presents a reduced field-of-view (FOV) single-shot echo-planar imaging (ss-EPI) method to address these problems and enable high-resolution diffusion MRI of targeted regions. The proposed method utilizes a two-dimensional (2D) echo-planar radio-frequency (RF) excitation pulse to achieve a sharp reduced-FOV profile, while still allowing contiguous multi-slice imaging and suppressing the fat signal. Extensive clinical evaluation of the technique demonstrated that sub-mm diffusion-weighted imaging (DWI) on human spinal cords is feasible with minimal artifacts. High-resolution fiber tractography of the spinal cord successfully visualized the connectivity between the cord and the medulla oblongata, delineating internal structures such as gray/white matter. In vivo DWI of the larynx, breast and prostate validated the effectiveness of this technique in providing detailed depiction of the morphology outside the central nervous system. When the exponential diffusion attenuation is combined with high spatial resolution, DWI may suffer from poor signal-to-noise ratio (SNR). The last part of this thesis presents an optimization strategy for the DWI parameters as a function of the imaging SNR. Specifically, the optimum b-value is shown to be a monotonically increasing function of the imaging SNR, with a convergence asymptote identical to the previously proposed values in literature. The effects of T2 relaxation are also incorporated for a more accurate optimization. In vitro and in vivo experiments demonstrated reduced error in ADC estimations and improved SNR in the diffusion-weighted images with the proposed technique.

Keywords: Electrical Engineering
Advisor: Nishimura Dwight George primary advisor. Thesis advisor
Hu Bob advisor. Thesis advisor
Pauly John (John M.) advisor. Thesis advisor
High-voltage-tolerant I/O design for USB 2.0-compliant systems [electronic resource]

The design of I/O user interfaces continues to grow in importance as the "digital revolution" gathers momentum. In such I/O interfaces, one frequently occurring challenge is the need to accommodate over-voltage conditions, in which the I/O signals range beyond the nominal voltage ratings of the I/O supplies. This vulnerability results from the fact that most I/O ports are exposed to users during operation, resulting in relatively uncontrolled terminations or even user abuse. This problem is exacerbated by a mismatch in the scaling rates of CMOS processes and I/O standards, forcing transistors with reduced voltage tolerance to implement interfaces with higher I/O voltages. The design problems associated with over-voltage conditions are important because it directly affects the lifetime of the product. In this work, we identify design challenges in the presence of over-voltage conditions and derive design guidelines for end-user systems taking a USB 2.0-compliant I/O as a test vehicle. We further demonstrate over-voltage-protected I/O circuits and high-robustness on-chip ESD protection in a 90-nm CMOS process. Our I/O circuit provides over-voltage protection against stress ranging from -1 to 5.25 V with continuous monitoring and compatibility with power-down mode. To enable this protection using today's CMOS technology, an additional bias voltage is used. Also, a dedicated over-voltage detection circuit with no static power consumption centrally controls protection paths to realize continuous monitoring. The protection concept of the I/O circuits integrated in the USB transmitters and receivers has been demonstrated with and without power present. Our ESD design realizes an extremely robust on-chip ESD protection concept, achieving an ESD robustness of 5 A TLP current, equivalent to an 8 kV HBM level, while fulfilling the over-voltage and high-speed requirements of the USB 2.0 system. The proposed architectures, employing SCR devices with triggering circuits implemented using a diode-string or a PMOS device, exhibit high ESD robustness, compatibility with over-voltage conditions, and suppressed interaction between the ESD circuit and regular I/O signaling in any state of system power.

Keywords: Electrical Engineering
Advisor: Lee Thomas primary advisor. Thesis advisor
Wong S. advisor. Thesis advisor
Wooley Bruce A.
How Long Will You Live: Using Life Insurance Prices to Infer Market Expectations About Improvements in Lifespan

Life insurance markets are immensely popular in the United States, helping families to smooth consumption in the event of the death of a primary earner. Insurance firms price these products to reflect the life expectancy of the purchaser. However, life expectancies change over time and steadily lengthened throughout the twentieth century as a result of technological progress in fields like nutrition, sanitation, and healthcare. Given this upward trend in lifespan, I question whether expectations of future increases in life expectancy influence life insurance prices. I build off of research by Alpert, Bhattacharya, and Sood (2004) to construct a theoretical model for insurance prices that excludes any potential expectations effects. By comparing this model to actual life insurance prices from the 1994 Health and Retirement Study (HRS), I observe whether expectations of improvements in medical technology drive life insurance prices downward. After making this comparison, I find no overwhelming evidence that market expectations had a substantial effect on the prices of life insurance products held by HRS respondents.

Keywords:  Department of Economics
Stanford Department of Economics
market expectation
life expectancy
Health and Retirement Study
Thesis
Advisor: Bhattacharya Jayanta
A hybrid model for timbre perception [electronic resource] : quantitative representations of sound color and density

Timbre, or the quality of sound, is a fundamental attribute of sound. It is important in differentiating between musical sounds, speech utterances, everyday sounds in our environment, and novel synthetic sounds. This dissertation presents quantitative and perceptually valid metrics for sound color and density, where sound color denotes an instantaneous (or atemporal) spectral energy distribution, and density denotes the fine-scale temporal attribute of sound. In support of the proposed metrics, a series of psychoacoustic experiments was performed. The quantitative relationship between the spectral envelope and subjective perception of complex tones was investigated using Mel-frequency cepstral coefficients (MFCC) as a representation of sound color. The experiments consistently showed that the MFCC model provides a linear and orthogonal coordinate space for human perception of sound color. The statistics for all twelve MFCC were similar at average correlation (R-squared or R2) of 85%, suggesting that each MFCC contains perceptually important information. The regression coefficients did suggest, however, the lower-order Mel-cepstrum coefficients may be more important in human perception than the higher-order coefficients. The quantitative relationship between the fine-scale temporal attribute and subjective perception of noise-like stimuli was investigated using normalized echo density (NED). Regardless of the sound color of the noise-like stimuli, the absolute difference in NED showed a strong correlation to the perceived dissimilarity with R2 of 93% on average. The other experiments showed that NED could represent the density perception in a consistent and robust manner across bandwidths--static noise-like stimuli having similar NED values were perceived as similar regardless of their bandwidth. Overall, with these experiments, NED showed a strong linear correlation to human perception of density, along with robustness in estimating the perceived density across various bandwidths, demonstrating that NED is a promising model for density perception. The elusive nature of timbre description has been a barrier to music analysis, speech research, and psychoacoustics. It is hoped that the metrics presented in this dissertation will form the basis of a quantitative model of timbre perception.

Keywords: Music
Advisor: Berger Jonathan primary advisor. Thesis advisor
Chafe Chris advisor. Thesis advisor
Smith Julius O. (Julius Orion) advisor. Thesis advisor