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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Extended stochastic dynamics : theory, algorithms, and applications in multiscale modelling and data science

Shang, Xiaocheng January 2016 (has links)
This thesis addresses the sampling problem in a high-dimensional space, i.e., the computation of averages with respect to a defined probability density that is a function of many variables. Such sampling problems arise in many application areas, including molecular dynamics, multiscale models, and Bayesian sampling techniques used in emerging machine learning applications. Of particular interest are thermostat techniques, in the setting of a stochastic-dynamical system, that preserve the canonical Gibbs ensemble defined by an exponentiated energy function. In this thesis we explore theory, algorithms, and numerous applications in this setting. We begin by comparing numerical methods for particle-based models. The class of methods considered includes dissipative particle dynamics (DPD) as well as a newly proposed stochastic pairwise Nosé-Hoover-Langevin (PNHL) method. Splitting methods are developed and studied in terms of their thermodynamic accuracy, two-point correlation functions, and convergence. When computational efficiency is measured by the ratio of thermodynamic accuracy to CPU time, we report significant advantages in simulation for the PNHL method compared to popular alternative schemes in the low-friction regime, without degradation of convergence rate. We propose a pairwise adaptive Langevin (PAdL) thermostat that fully captures the dynamics of DPD and thus can be directly applied in the setting of momentum-conserving simulation. These methods are potentially valuable for nonequilibrium simulation of physical systems. We again report substantial improvements in both equilibrium and nonequilibrium simulations compared to popular schemes in the literature. We also discuss the proper treatment of the Lees-Edwards boundary conditions, an essential part of modelling shear flow. We also study numerical methods for sampling probability measures in high dimension where the underlying model is only approximately identified with a gradient system. These methods are important in multiscale modelling and in the design of new machine learning algorithms for inference and parameterization for large datasets, challenges which are increasingly important in "big data" applications. In addition to providing a more comprehensive discussion of the foundations of these methods, we propose a new numerical method for the adaptive Langevin/stochastic gradient Nosé-Hoover thermostat that achieves a dramatic improvement in numerical efficiency over the most popular stochastic gradient methods reported in the literature. We demonstrate that the newly established method inherits a superconvergence property (fourth order convergence to the invariant measure for configurational quantities) recently demonstrated in the setting of Langevin dynamics. Furthermore, we propose a covariance-controlled adaptive Langevin (CCAdL) thermostat that can effectively dissipate parameter-dependent noise while maintaining a desired target distribution. The proposed method achieves a substantial speedup over popular alternative schemes for large-scale machine learning applications.
32

Trauma, Gendered Violence and Coping-mechanisms in Colleen Hoover’s It Ends With Us

Rundqvist, Jonna January 2020 (has links)
This essay analyses the representation of trauma and gendered violence in Colleen Hoover’s novel It Ends With Us. To do this, trauma theory and the notion of gendered violence are applied in the analysis, as well as Dorrit Cohn’s ideas of diary novels, dissonant narrator and consonant narrator. The findings show that the protagonist, Lily’s, way of coping with her trauma and gendered violence during her teenage years, was to keep a diary, effectively using scriptotherapy. When that was not enough, however, she actively suppressed her problems. The essay also shows that Cohn’s ideas of dissonant and consonant narrator play a part in how Lily’s development is shown throughout the novel.
33

From Mission to Megacity: The Changing Concentration of the Los Angeles City-system

Cosby, Kerri L. 20 April 2004 (has links) (PDF)
Having an understanding of when, where, and why people settle in an area is crucial in explaining the growth course of a city. However, this cannot be done by looking at a city in isolation. Its surrounding region has a tremendous impact on its development. The purpose of this thesis is to examine the growth of Los Angeles from a regional perspective, called the Los Angeles city-system, which consists of Los Angeles and its hinterland. Connections are made between the history and the geography of the Los Angeles city-system by examining the spatial distribution of population within the region between 1769 and 2000. The Hoover Index of Population Concentration is used to determine the population concentration, and major shifts in the concentration are illuminated by the geography and historical events of the Los Angeles area. The main factors contributing to the changing concentration were the region's physical geography, the introduction of transportation innovations, the region's economic structure, historical and political events, and migration trends. It was found that the counties in closest proximity to Los Angeles County are becoming more alike, while the more peripheral counties are becoming more different. This has led to a greater understanding of urban/periphery growth economics.
34

Early Leader Effects on the Process of Institutionalization Through Cultural Embedding: The Cases of William J. Donovan, Allen W. Dulles, and J. Edgar Hoover

Painter, Charles N. 09 May 2002 (has links)
This study examines the ways early leaders can influence the process of institutionalization in public organizations. Using Schein's (1983, 1991) model of cultural creation and embedding as a heuristic device, secondary historical sources detailing the creation and development of the Central Intelligence Agency (CIA) and the Federal Bureau of Investigation (FBI) and the careers of three significant leaders are used to understand the institutionalizing effects of those leaders, how they created those effects, and what happened to those effects over time. The case studies of William Donovan and Allen Dulles at CIA and J. Edgar Hoover at the FBI, provide evidence that these early leaders explicitly and implicitly used several of the cultural creation and embedding mechanisms identified by Schein to entrench their beliefs and predispositions into their organizations. These ensconced attitudes and tendencies seemingly played significant roles in the institutionalization of beliefs, rules, and roles that have developed, persisted, and affected the historical evolution of both CIA and the FBI. / Ph. D.
35

Taking Off: The Politics and Culture of American Aviation, 1920-1939

Johnson, McMillan Houston, V 01 May 2011 (has links)
Historians have traditionally emphasized the sharp differences between Herbert Hoover’s vision of an associational state and the activism of Franklin D. Roosevelt’s New Deal. This dissertation highlights an important area of continuity between the economic policies espoused by Hoover—during his tenures as Secretary of Commerce and President—and Roosevelt, focusing on federal efforts to promote the nascent aviation industry from the end of World War I until the passage of the Civil Aeronautics Act in 1938. These efforts were successful, and offer a unique arena in which to document the concrete gains wrought by Hoover’s associationalist ideology and Roosevelt’s New Deal. Moreover, both Hoover’s corporatist policies and New Deal efforts to create aviation infrastructure—largely through the auspices of public works agencies like the Public Works Administration and Works Progress Administration—form a striking example of the government’s ability to successfully foster the development of a new industry, even in the midst of the Great Depression. Significantly, both men’s efforts represented an alternative to nationalization, the path taken by virtually every European nation during the era. This period thus offers the opportunity to examine how both presidents’ aviation policies cohere with their larger visions of government’s proper relationship to the economy, to compare and contrast associationalism and New Deal, and to elucidate aviation’s role in promoting American economic development. During these years government actions expanded from having literally no engagement with commercial aviation to subsidizing airmail routes, creating a regulatory infrastructure to promote safe operations by licensing pilots, inspecting aircraft, approving manufacturing operations, and aggressively promoting flying to the American people. Contextualized by the American public’s well-documented enthusiasm for flying—particularly after Charles Lindbergh’s famous New York-to-Paris flight in 1927—these federal actions created America’s modern air transport network, culminating in the passage of the seminal Civil Aeronautics Act of 1938, the construction and improvement of almost a thousand airports around the country, and the growth of a core group of airlines, including United, Delta, and American, that still dominate commercial flying today.
36

The scales are still unbalanced a phenomenological study of parental involvement of lower socioeconomic students attending school in an affluent Southeastern educational community /

Smith, Debra Walker. January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: Lois M. Christensen, Lynn D. Kirkland, Maryann Manning, Dorothy Riley. Description based on contents viewed June 12, 2008; title from title screen. Includes bibliographical references (p. 121-126).
37

The scales are still unbalanced : a phenomenological study of parental involvement of lower socioeconomic students attending school in an affluent Southeastern educational community /

Smith, Debra Walker. January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: Lois M. Christensen, Lynn D. Kirkland, Maryann Manning, Dorothy Riley. Includes bibliographical references (p. 121-126).
38

Parent perceptions of invitations for involvement : effects on parent involvement at home and school

Cox, Diane Denise 27 January 2011 (has links)
Research has demonstrated much evidence for the positive effect of parent involvement on academic achievement in children (Jeynes, 2003, 2007; Hoover-Dempsey, Walker, Sandler, Whetsel, Green, Wilkins, & Closson, 2005; Fan & Chen, 2001; Griffith, 1996). As children from low income and ethnic minority families are at the greatest risk for academic failure, it is important to study the processes that lead parents to become involved within at-risk populations. A comprehensive model such as the one proposed by Hoover-Dempsey and Sandler (1995, 1997) provides a map of important constructs to study. Research using this model appears promising as a way to conceptualize the processes that lead to parent involvement (Walker, Wilkins, Dallaire, Sandler, & Hoover-Dempsey, 2005). However, there are few studies that have tested this model with minority populations, and none that have focused on a primarily Latino population. Parent involvement research indicates inconsistent findings regarding the role of family background variables in the process of parent involvement (Ho & Willms, 1996; Griffith, 1998). The purpose of this study was to examine the effects of parent perceived invitations for involvement on parent involvement behavior with a primarily low-income, urban, Latino population. Two levels of the Hoover-Dempsey and Sandler model were tested: parent perceived invitations for involvement (child invitations, school invitations, and teacher invitations) and parent involvement behavior (home-based and school-based). Child invitations and teacher invitations were both found to be important types of invitation for total parent involvement (home-based and school-based combined). Home language, employment status, and parent education level moderated the effect of child invitations on total parent involvement. When parent involvement was differentiated into home-based and school-based involvement as separate dependent variables, child invitations had a significant effect on both types of involvement. Home language, employment status, and parent education level moderated the effect of child invitations on home-based parent involvement. For this population, child invitations for involvement appear to be the most important means to invite parent participation. Future research should continue to investigate the utility of Hoover-Dempsey and Sandler’s model of parent involvement with specific ethnic groups, and consider family background variables due to their potentially moderating role. / text
39

ELWOOD MEAD: IRRIGATION ENGINEER AND SOCIAL PLANNER

Kluger, James R. January 1970 (has links)
No description available.
40

Appeals for “One Million Belgian Children”: Understanding the Success of the Commission for Relief in Belgium through the Mudd Family Papers

Key, Brian David 01 January 2015 (has links)
In response to the German occupation of Belgium in World War I, future U.S. president Herbert Hoover and a handful of his colleagues in the mining engineer industry founded the Commission for Relief in Belgium (CRB). The CRB engineered one of the greatest relief movements in history partly on account of its successful public appeals; nevertheless, the success of these appeals has never been fully explained due to a remarkable dearth of scholarship on the topic. This paper seeks to fill in the gap by analyzing salient documents in the Mudd Family Papers, located in Honnold/Mudd Library’s Special Collections section. The artifacts ultimately evince that the CRB tailored its appeals to the American upper and middle classes, appropriating their respective motifs and lexicons to successfully mobilize both groups; that rumors of wartime atrocities against Belgian children augmented its appeals to the middle class; and that it issued targeted messages to its American supporters after the United States’ entry into World War I, maintaining vital public support. The findings of this paper promise to add invaluable knowledge to an exceedingly understudied historical subject.

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