VictorJuiz/thesis huggingface dataset:
Lateral interactions in organic functionalization of semiconductor surfaces [electronic resource]

As the size scale of current electronic devices is reaching a fundamental physical limit, new and innovative materials solutions are required for continuous progress of semiconductor technologies. Moreover, the development of nanotechnologies comprised of nanoscale materials is burgeoning in various fields. Nanomaterials often show completely different properties compared to their bulk, dominated by surfaces or interfaces. Given the importance of these interfaces, organic functionalization of semiconductor surfaces, or direct attachment of organic molecules, is a topic of increasing interest. By creating interfaces between inorganic and organic functionalities, we may be able to tune the properties of the surface with the versatility and tailorability of organic molecules. In order to utilize organic functionalization in such applications, a deep understanding of the adsorption of the molecules on the surfaces is necessary. In this work, we focus on the fundamental aspects of the adsorption chemistry of organic molecules on a semiconductor surface, and on the lateral interactions between the adsorbed molecules. We explore several molecules' adsorption chemistry on the Ge(100)-2×1 surface. Experimental techniques such as infrared spectroscopy, X-ray photoelectron spectroscopy, and temperature programmed desorption, in addition to theoretical methods including density functional theory calculations and Monte Carlo simulations, are utilized. The strongest interaction that drives the adsorption of the molecules on the surface is local bond formation between the molecules and "dimers" of the Ge(100)-2×1 surface, such as C-dative bonding of isocyanides, dissociative adsorption of phenols, and cycloaddition of nitrobenzene. However, weaker lateral interactions between the adsorbates or between adsorbates and the surface are also present, and they significantly affect the adsorption of the molecules, especially at higher coverages of the adsorbates. In studies of adsorption of small molecules that interact with one dimer, we observe a coverage-dependant spectral shift of tert-butyl isocyanide, and explain self-assembly of methanol and ethylene that had been reported in the literature. Slightly larger molecules can interact with other neighboring dimers: we show that phenol undergoes a shift in molecular orientation due to non-covalent adsorbate-surface interactions, and we determine that coverage-dependent evolution of dual and single adsorption products of benzenediols originates from inter-adsorbate interactions. Overall, this dissertation provides new insights toward the organic functionalization of semiconductor surfaces.

Keywords: Chemical Engineering.
Advisor: Bent Stacey primary advisor. Thesis advisor
Bao Zhenan advisor. Thesis advisor
Nørskov Jens K.
Learning to "stick to your guns": Exploring gender perceptions among Chinese graduate students in STEM fields

Women’s access to science education is receiving a growing amount of attention from the international community (Wotipka & Ramirez, 2003; Mok, 2005; Blickenstaff, 2005; Kabeer, 2005). China is increasing women’s access to higher education by encouraging women to pursue graduate degrees in the sciences. Although more women are completing graduate degrees, most women are not entering the sciences (Liu & Li, 2010). The following study examines gender-specific challenges that Chinese women face while pursuing graduate degrees in Science, Technology, Engineering, and Math (STEM) fields through an exploration of how participants perceive the role of Chinese culture in their relationships with peers and mentors.
Using a combination of psychological, sociological, and historical frameworks to contextualize gender inequality, I analyzed 8 interviews and 35 survey responses from graduate students pursuing STEM degrees in China. The experiences of my participants reveal culturally determined behavioral barriers that may limit a woman’s ability to challenge authority in higher education settings. Exploring the experiences of female scientists in a different cultural context might help us better understand how to create more inclusive scientific communities by revealing any culturally constructed barriers that discourage or exclude. By acknowledging certain barriers to access, we can then address how to eliminate these barriers.

Keywords: gender
science
China
education
Graduate School of Education
Thesis
Leases [electronic resource] : service contracts or investment and financing?

This study seeks to address what lease attributes separate service contracts from investment and financing for leases from the perspectives of both users and preparers. Based on the prediction of future operating income and the assessment of equity risk, my findings suggest that the lessee's effective ownership percentage, not the real estate/equipment partition proposed by the standard setters, helps separate service contracts from investment and financing transactions for leases. Hence, a classification method based on the lessee's effective ownership percentage reflects the heterogeneity of leases better than that based on the real estate/equipment partition. Using disclosed contingent and minimum rental payments from retailers, I find that only contingent rental payments are significantly reduced in economic downturns. For instance, the ratio of contingent rental payments to sales declines by 32% from 2008 to 2009, whereas the ratio of minimum rental payments to sales increases by 6% in the same period. I also provide evidence that investors include minimum rental payments but ignore contingent rental payments in the assessment of equity risk. Therefore, based on different behaviors in business cycles and equity risk assessment, my findings support excluding contingent rental payments from the measurement of lease assets and liabilities. Finally, I analyze the comment letters submitted by preparers, and find that real estate lessees are more likely to oppose treating all leases as investment and financing than equipment lessees.

Keywords: Business.
Advisor: Barth Mary E. primary advisor. Thesis advisor
Beaver William advisor. Thesis advisor
McNichols Maureen
Piotroski Joseph D. (Joseph David) advisor. Thesis advisor
Legion [electronic resource] : programming distributed heterogeneous architectures with logical regions

Modern supercomputers now encompass both heterogeneous processors and deep, complex memory hierarchies. Programming these machines currently requires expertise in an eclectic collection of tools (MPI, OpenMP, CUDA, etc) that primarily focus on describing parallelism while foisting the burden of data movement onto the programmer. Legion is an alternative approach to programming supercomputers that introduces logical regions as a relational model for describing program data. Logical regions can be dynamically partitioned into sub-regions giving applications an explicit mechanism for directly conveying information about the structure and usage of program data to the Legion runtime system. Using this information, the Legion runtime can automatically extract task parallelism from programs based on logical region usage. Furthermore, Legion can automate the movement of data through the memory hierarchy consistent with programmer-specified privilege and coherence annotations on logical regions. A novel mapping interface places total control over the placement of tasks and regions in the machine in the hands of the programmer. The Legion mapping interface also decouples the correctness of applications from performance decisions making Legion applications easy to port and tune for new architectures. We evaluate our implementation of Legion on several benchmark applications as well as a full port of S3D, a production combustion simulation running on Titan, the number two supercomputer in the world.

Advisor: Aiken Alexander primary advisor. Thesis advisor
Dally William J. advisor. Thesis advisor
Hanrahan P. M. (Patrick Matthew) advisor. Thesis advisor
Legitimacy and democracy [electronic resource] : a platonic defense of voluntary rule

Democracy is widely recognized as a distinctively legitimate form of government. In this dissertation I evaluate democracy's claim to political legitimacy. I propose a new theory of political legitimacy based on an ideal of voluntary rule, and I call this view the sovereignty conception. The sovereignty conception of legitimacy employs an interpretation of political freedom as voluntary acceptance of rule, based on the positive governance assessments of individual subjects. Thus, I develop and defend the view that a political order is legitimate to the degree that it achieves widespread consent among subjects on the basis of governance outcomes. Due to its orientation to both quality of outcomes and actual consent to rule, the sovereignty conception offers a novel way to value consent in the political domain. Accordingly, I argue that it addresses important shortcomings in other consent theories of legitimacy, namely, voluntarism and contractualism. I also show the advantages of the sovereignty conception of political legitimacy as compared to two alternative accounts that are not based on consent, Philip Pettit's republicanism and Bernard Williams's political realism. Furthermore, I argue that an ideal of voluntary rule that resonates with the sovereignty conception can be found in Plato's Laws, in which he both distinguishes freedom from justice and emphasizes freedom's distinct value. I develop and defend a new interpretation of the Laws, according to which proper political rule involves respect for the freedom of citizens by aiming at their free acceptance of rule. Finally, I utilize the sovereignty conception of legitimacy to propose an alternative argument for the legitimacy of democracy. According to the sovereignty conception, a democracy is legitimate because it prioritizes actual quality consent over other welfare outcomes through its institutional mechanisms of responsiveness to popular approval and disapproval. I argue that the legitimacy of democracy is better defended by the sovereignty conception than by views based on equality or hypothetical consent, and I analyze in particular the democratic theories of Thomas Christiano, David Estlund, and Joshua Cohen. I propose a new way of combining instrumental and non-instrumental elements in an argument for democracy, resulting in a defense that preserves the distinct contributions of democracy's instrumental and non-instrumental value. Ultimately, I show that the personal sovereignty conception of political legitimacy affords a promising new route to justifying the legitimacy of democracy. Thus, the sovereignty conception of political legitimacy represents a novel approach, one that seeks to articulate the distinct value of political legitimacy vis-à-vis other political values.

Keywords: Philosophy.
Advisor: Cohen Joshua
Bobonich Christopher advisor. Thesis advisor
Satz Debra advisor. Thesis advisor
Wood Allen W. advisor. Thesis advisor
Leveraging intuitive theories to teach nutrition to young children [electronic resource]

A large body of research in cognitive development suggests that from early in life, children construct coherent belief systems, or intuitive theories, to understand, predict, and explain the world. Gripshover and Markman (2013) harnessed this insight to create an intervention tailored for teaching young children that foods have different nutritional profiles—no one food provides all the nutrients the body needs—and therefore we need a variety of healthy foods. Learning this framework required children to overcome gaps and misconceptions in their developing intuitive theories, but children nevertheless learned and generalized this new theory, used it to explain the importance of variety, and even ate more vegetables at snack time. The current research demonstrates that the materials are likely to be appropriate educational for a wide range of populations of preschool to first-grade children (Study 1), that children spontaneously appeal to the conceptual framework to explain a wide range of novel facts and claims (Study 2), and that the intervention may even encourage children to recognize the importance of individual ingredients in determining the health value of composite dishes, such as stew and salad (Study 3). Together, these results provide a model of how to construct and evaluate health education materials that teach young children the science behind health-related domains such as nutrition.

Keywords: Psychology.
Advisor: Markman Ellen M.
Frank Michael C. (Professor of human biology) advisor. Thesis advisor
Walton Gregory M. (Gregory Mariotti) advisor. Thesis advisor
Live imaging of biological processes [electronic resource] : from single-cell NF-[kappa]B signaling to single-molecules in bacterial cell growth

Cellular systems are constantly undergoing change, ranging from sudden responses to shifts in the extracellular environment to the more constant advancement of cell growth and cell division. Given the dynamic nature of biological processes, a great deal of insight can be gained simply by watching and recording their behavior over time. With improvements in microscopy and imaging techniques, we are now able to observe the dynamics of biological processes in live systems at the single-cell and single-molecule level. In this dissertation, I discuss two research projects where quantifying the behavior of live, individual cells provide new insights into how noise and variation play important roles. In the first study, we quantified and modeled the activation dynamics of the transcription factor nuclear factor (NF)-[kappa] B in response to stimulation by the cytokine tumor necrosis factor-[alpha] (TNF-[alpha]) and the bacterial immune challenge lipopolysaccharide (LPS). Using live, single-cell imaging, we show that the variation in LPS responses can be attributed to a 'noisy' paracrine signal. In the second study, we characterized the coordination between two proteins that confer cell shape in the bacterium Escherichia coli, the cytoskeletal protein MreB and the cell wall synthase penicillin binding protein 2 (PBP2). Our measurements of PBP2 suggest that single molecules of PBP2 undergo random, diffusive movements where PBP2 transiently interacts with the rest of the synthesis machinery. Furthermore, we show that one feature of this behavior is to buffer cell wall growth rate against large fluctuations in enzyme abundance.

Keywords: Bioengineering.
Advisor: Huang Kerwyn Casey
Bryant Zev David advisor. Thesis advisor
Covert Markus advisor. Thesis advisor
Long-time atom interferometry for precision tests of fundamental physics [electronic resource]

Light-pulse atom interferometry is a technique that is exquisitely sensitive to inertial forces. As such, it has exciting applications both in fundamental physics for precision tests of gravity, electrodynamics and quantum mechanics, as well as in practical situations for inertial navigation, geodesy, and timekeeping. In this work, I describe a 10 meter atomic fountain, designed for a precision test of the weak equivalence principle but with additional relevance in bounding proposed modifications of quantum mechanics, directly measuring general relativistic corrections, and detecting gravitational waves. This system is demonstrated to have the largest acceleration sensitivity to date by two orders of magnitude (6.7e-12 g). I also present precision measurements of Earth's rotation, the preparation of ultracold clouds to picokelvin effective temperatures, and current work to further improve the acceleration sensitivity through meter-scale separation between two halves of the atomic wavepacket. I close with a discussion of the next step towards an equivalence principle test: the creation of a well-overlapped, dual-species ultracold cloud.

Keywords: Physics.
Advisor: Kasevich Mark A. primary advisor. Thesis advisor
Mabuchi Hideo advisor. Thesis advisor
Michelson Peter F. advisor. Thesis advisor
Loose Lips Build Ships? Secrecy and Human Capital Management in US NSA and Israel Unit 8200

How do intelligence organizations attract and make use of top talent? This paper approaches this question through a comparative case study of the labor ecosystems surrounding both the US’ National Security Agency and IDF’s signals intelligence branch, Unit 8200. As the cyber realm continues to assume a growing role in modern national security threat environments, intelligence organizations must grow and adapt to accommodate these new objectives. This inevitably involves the question of how to attract and make use of top talent in order to solve difficult and highly technical national security problems. Israel and the United States share similar national security interests, and both possess burgeoning and impressive high-technology clusters. This paper claims that a growing, public network of Unit 8200 and other Intelligence Corps alumni is extant in Israel’s high-technology sector. Furthermore, affiliation with Unit 8200 has a positive signaling and social capital value. By contrast, this paper argues that alumni from the NSA do not possess as strong of a signaling or social capital value in the US. This paper argues that the NSA is hindered by the ontology, secrecy, and culture of the organization itself, as well as US public understanding of national security organizations and cyber threats. In Israel, this paper suggests that that Unit 8200’s associated signaling and social capital value benefits its alumni, Israel’s technology sector, and the unit itself. This paper argues that this phenomenon is unusual, and despite the uniqueness of Israel’s national security system, is prescriptive for the United States, where social capital and signaling is not directly leveraged by intelligence organizations as a recruiting tool. This paper argues that increasing the professional signaling and social capital value associated with intelligence organization affiliation is good for the organizations themselves by helping attract and make use of talent.

Keywords: Israel
IDF
Unit 8200
NSA
Signalling Theory
Networks
Human Capital
Center for International Security and Cooperation
Thesis
Advisor: Cuellar Mariano-Florentino
Felter Colonel Joseph
Macro-adaptive algorithms [electronic resource]

Traditionally, new adaptive algorithms were developed 'microscopically' by changing the internal structure of LMS, Recursive Least Squares (RLS) and their variants, such as update equations and optimization criteria. This research attempts to reignite the interest in improving adaptive algorithms by considering a different question: by treating any known adaptive algorithm as a black-box learning agent, what can we do to leverage these little learner(s) to form a more intelligent adaptive algorithm? A framework is developed in this thesis to guide the design process, in which algorithms created from the framework are only allowed to manipulate these little black-boxes without hacking into their inner workings. Since it is a block-level (macroscopic) design strategy, the framework is called 'Macro-Adaptive Framework' (MAF) and algorithms developed from the framework are called 'Macro-Adaptive Algorithms' (MAA), hence the name of the thesis. In this thesis, macro-adaptive framework (MAF) will be defined. Algorithms satisfying the framework, including new ones developed by the author, will be discussed, analyzed, and compared with other existing algorithms, followed by simulation results in adaptive system identification. Since MAF opened the flood-gate for aggressive optimization (squeezing more information out of limited number of samples) that was not previously available, one possible side effect is over-adaptation, which is rarely studied in adaptive filtering literature. In addition to solutions developed in the thesis, the author did some original research on the phenomenon and the results are presented in the thesis as well.

Keywords: Electrical Engineering.
Advisor: Widrow Bernard
Making with understanding [electronic resource] : research on studies from a constructionist learning environment

"Making" has become a 21st century education buzzword. Educators, entrepreneurs, researchers and politicians all seem to galvanize around the possibility for "making" to launch an educational revolution. However, to date, there has been little research that systematically investigates what and how students are learning in the context of "making." This dissertation serves to shed light on these questions, while also providing recommendations for how to improve the culture and practices of "making." Specifically I use data from three studies to document common strategies students use in constructionist learning, and demonstrate how those strategies result in differences in project quality, student learning, and the overall process in which students engage.

Keywords: Education.
Advisor: Blikstein Paulo
Brown Bryan Anthony advisor. Thesis advisor
Schwartz Dan
Markov process regression [electronic resource]

Regression analysis, the process of estimating the relationship between some dependent and independent variables from empirical data is widely used in many fields including medicine, economics, and machine learning. While many different approaches to regression exist, two important distinctions are whether it is assumed that the relationship has a specific parametric form (e.g., linear) and whether the resultant prediction is deterministic (e.g., when minimizing the sum of squares) or probabilistic. When no specific parametric form is assumed and the prediction is probabilistic, the regression is referred to as nonparametric and Bayesian, respectively. In this dissertation, a broad family of nonparametric Bayesian regression models is introduced, where the prior is assumed to be a Markov process. In comparison to the more common Gaussian process prior, this choice has several advantages such as performance which is not dependent on the form of the likelihood functions and the ability to enforce monotonicity of a relationship a priori. A primary contribution of this dissertation is an algorithm for efficiently updating Markov process priors from experimental data. While this algorithm is based on the forward-backward algorithm for discrete hidden Markov models, extension to the continuous case is not trivial. First, since the transition densities for Markov processes cannot be calculated analytically, simulation methods are used instead. Secondly, existing simulation methods can be extremely inefficient for calculating these updated densities. To circumvent this issue, a new simulation technique is developed that significantly improves the efficiency of these calculations. Lastly, some benefits that Markov process regression has over existing regression methods are illustrated through applied problems. In particular, applications in medicine, consumer science, and manufacturing are presented.

Keywords: Management Science and Engineering.
Advisor: Howard Ronald A. (Ronald Arthur)
Chiu Samuel S. advisor. Thesis advisor
Shachter Ross D. advisor. Thesis advisor