Thesis (M.A.)--Trinity Evangelical Divinity School, 2002. / Abstract. Includes bibliographical references (leaves 109-116).

Thesis (Ph. D.)--University of California, San Diego, 2003. / Vita. Includes bibliographical references (leaves 227-238).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Our group has developed a Bayesian modeling technique to determine the ages of stellar populations (in particular, open and globular clusters) using white dwarf (WD) cooling physics. As the theory of WD cooling is both simpler than, and essentially independent of, main sequence evolutionary theory, white dwarfs provide an independent measure of the ages of Galactic populations. We have developed a Bayesian technique that objectively incorporates our prior knowledge of stellar evolution, star cluster properties, and data quality estimates to derive posterior probability distributions for a cluster's age, metallicity, distance, and line-of-sight absorption, as well as the individual stellar parameters of mass, mass ratio (for unresolved binaries) and cluster membership probability. The key advantage of our Bayesian method is that we can calculate probability distributions for cluster and stellar parameters with reference only to known, quantifiable, objective, and repeatable quantities. In doing so, we also have more sensitivity to subtle changes in cluster isochrones than traditional ``chi-by-eye'' cluster fitting methods. As a critical test of our Bayesian modeling technique, we apply it to Hyades UBV photometry, with membership priors based on proper motions and radial velocities, where available. We use secular parallaxes derived from Hipparcos proper motions via the moving cluster method to put all members of the Hyades at a common distance. Under the assumption of a particular set of WD cooling and atmosphere models, we estimate the age of the Hyades based on cooling white dwarfs to be 610 +- 110 Myr, consistent with the best prior analysis of the cluster main-sequence turn-off age (Perryman, et al. 1998). Since the faintest white dwarfs have most likely evaporated from the Hyades, prior work provided only a lower limit to the cluster's white dwarf age. Our result demonstrates the power of the bright white dwarf technique for deriving ages (Jeffery, et al. 2007) and further demonstrates complete age consistency between white dwarf cooling and main-sequence turn-off ages for seven out of seven clusters analyzed to date, ranging from 150 Myr to 4 Gyr. We then turn our attention to the white dwarf luminosity function. We use Sloan Digital Sky Survey (SDSS) data to create a white dwarf luminosity function with nearly an order of magnitude (3,358) more spectroscopically confirmed white dwarfs than any previous work. We determine the completeness of the SDSS spectroscopic white dwarf sample by comparing a proper-motion selected sample of WDs from SDSS imaging data with a large catalog of spectroscopically determined WDs. We derive a selection probability as a function of a single color (g-i) and apparent magnitude (g) that covers the range -1.0 < g-i < 0.2 and 15 < g < 19.5. We address the observed upturn in log g for white dwarfs with Teff < ~12,000K and offer arguments that the problem is limited to the line profiles and is not present in the continuum. We offer an empirical method of removing the upturn, recovering a reasonable mass function for white dwarfs with Teff < 12,000K. Finally, we outline several other current and future applications of our method and our code to determine not only ages of Galactic stellar populations, but helium abundances of clusters, ages of individual field WDs, and the initial (main sequence) to final (WD) mass relation. / text

This report looks at the system of alleys that exist in downtown Austin, Texas and proposes a way to integrate them into the open space network within the area by creating a series of alley connections. Through analysis of case studies from other cities and public space theories, alternative methods of use are suggested for implementation throughout the alley system, including “green”, activity based and pedestrian and bicycle priority throughways. The next steps needed to create a Downtown Alley Master Plan and begin alley renovations are also discussed. The renovation of spaces that typically contain unsightly uses and activities can help create attractive places for people to congregate rather than places that people generally avoid. / text

published_or_final_version / Architecture / Master / Master of Landscape Architecture

Modern cities do not only aim at focusing on economic development solely, but they also need to provide high quality of urban living environment which could achieve social, economic and environmental sustainability. Public open space constitutes an indispensible part in achieving this planning objective. Nevertheless, open space is not a unitary planning concept. It has been being constantly redefined to suit changing social and economic needs. This study investigates the development of land supply and land-use planning of public open space in Hong Kong. It attempts to examine how open space was understood, planned, and provided in different periods in Hong Kong. Open space is presumed to be influenced by the interplay of three main social forces, namely the government, the capitalists, and the people. The interplay of the three forces changes in different periods of time in Hong Kong, resulting in the changing meaning and transformation of open space in the aspects of locations, forms, distributions, and ways of provisions. My key arguments are as follows: In the pre-Second World War colonial period, extraction was regarded as the primary objective of the colonial government. Since the colonial atmosphere shared the idea of earning from re-exporting trade and temporal stay, public open space, except for private leisure facilities, was not truly a concern of any of the social groups. While recreational opportunities and open space were still necessary to attract foreign investments and provide political functions, the colonial government provided open space in a residual manner, utilizing urban fringe areas of Victoria City and existing land-uses for open space functions. To maximize the use of open space, though the government was reluctant to provide, open space was utilized for political functions to preach social conforming behaviours and Western lifestyle to the Chinese immigrants as well as to new Chinese generations. The post-Second World War open space development was characterized by an expansion of the scope of open space, as well as political reform of the municipal governments and the planning institution. Triggered by the large influx of Chinese refugees that migrated to Hong Kong and the rising population of the local-born Chinese youngsters, elected representatives were introduced to the municipal councils. These elected representatives endeavoured to urge the government to provide open space where available, persuading the government by giving new meanings to open space. The planning institution, however, continued to plan open space in a residual manner. Inspired by the Abercrombie Plan, open space was planned towards the countryside and new forms of open space were introduced to expand the scope of open space. The contemporary pattern of public open space is examined by quantitative analyses. Three kinds of open space are examined, namely zoned open space, administered public open space, and public open space within private developments. Results show that large-scale zoned open spaces tend to cluster in urban fringe areas and countryside, whereas zoned open spaces in urban areas tend to be fragmentary. Waterfront and coastal areas, whether in urban or rural areas, are commonly utilized for open space purposes. These findings echo the planning strategy, aiming at shifting open space from the inner urban areas to the urban fringe and rural areas. Administered public open spaces are found to be related to the income level and the ratio of occupational status of a community. The analyses of planning applications further suggest that open space serves as the potential land reserve for various uses instead of being a mere recreational site. Public open spaces within private developments are provided more flexibly compared to conventional public open space in terms of their physical forms and regulations. The manipulations are found to be wittingly introduced by the developers to suit their parochial interests. It is expected that open space will be subject to constant redefinition under further socioeconomic developments and changing compositions of the three social forces. / published_or_final_version / Urban Planning and Design / Doctoral / Doctor of Philosophy

First-principles electronic structure theory explains properties of atoms, molecules and solids from underlying physical principles without input from empirical parameters. Time-dependent density functional theory (TDDFT) has emerged as arguably the most widely used first-principles method for describing the time-dependent quantum mechanics of many-electron systems. In this thesis, we will show how the fundamental principles of TDDFT can be extended and applied in two novel directions: The theory of open quantum systems (OQS) and quantum computation (QC). In the first part of this thesis, we prove theorems that establish the foundations of TDDFT for open quantum systems (OQS-TDDFT). OQS-TDDFT allows for a first principles description of non-equilibrium systems, in which the electronic degrees of freedom undergo relaxation and decoherence due to coupling with a thermal environment, such as a vibrational or photon bath. We then discuss properties of functionals in OQS-TDDFT and investigate how these differ from functionals in conventional TDDFT using an exactly solvable model system. Next, we formulate OQS-TDDFT in the linear-response regime, which gives access to environmentally broadened excitation spectra. Lastly, we present a hybrid approach in which TDDFT can be used to construct master equations from first-principles for describing energy transfer in condensed phase systems. In the second part of this thesis, we prove that the theorems of TDDFT can be extended to a class of qubit Hamiltonians that are universal for quantum computation. TDDFT applied to universal Hamiltonians implies that single-qubit expectation values can be used as the basic variables in quantum computation and information theory, rather than wavefunctions. This offers the possibility of simplifying computations by using the principles of TDDFT similar to how it is applied in electronic structure theory. Lastly, we discuss a related result; the computational complexity of TDDFT. / Physics

Not available / text

Virtualization is the key technology which has provided smarter and easier ways for effectively utilizing resources provided by the hypervisor. Virtualization allows multiple operative systems (OS) to run on a single hardware. The resources from a hardware are allocated to virtual machines (VM) by hypervisor. It is important to know how the performance of virtual switches used in hypervisor for network communication affect the network traffic.   Performance of Linux Bridge (LB) and Open vSwitch (OVS) is investigated in this study. The method that has been used in this research is experimentation. Two different scenarios are used to benchmark the performance of LB and OVS in virtual and non-virtual environment. Performance metrics bitrate is used to benchmark the performance LB and OVS. The results received from the experimental runs contains the ingress bitrate and egress bitrate of LB and OVS in virtual and non-virtual environment. The results also contain the ingress and egress bitrate values from scenarios with different memory and CPU cores in virtual environment. Results achieved in this thesis report are from multiple experiment configurations. From results it can concluded that LB and OVS have almost same performance in non-virtual environment. There are small differences in ingress and egress of both virtual switches.