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  • Thesis

  • Authors: Gamber, Emily (2006)

  • We give a classification of cellular automata in arbitrary dimensions and on arbitrary subshift spaces from the point of view of symbolic and topological dynamics. A cellular automaton is a continuous, shift-commuting map on a subshift space; these objects were first investigated from a purely mathematical point of view by Hedlund in 1969. In the 1980’s, Wolfram categorized one-dimensional cellular automata based on features of their asymptotic behavior which could be seen on a computer screen. Gilman’s work in 1987 and 1988 was the first attempt to mathematically formalize these characterizations of Wolfram’s, using notions of equicontinuity, expansiveness, and measure-theoretic analogs of each. We introduce a topological classification of cellular automata in dimensions two and hi...

  • Thesis

  • Authors: Tam, Mary C. (2006)

  • Coupled cluster (CC) and density functional theory (DFT) are highly regarded as robust quantum chemical methods for accurately predicting a wide variety of properties, such as molecular structures, thermochemical data, vibrational spectra, etc., but there has been little focus on the theoretical prediction of optical rotation. This property, also referred to as circular birefringence, is inherent to all chiral molecules and occurs because such samples exhibit di erent refractive indices for left- and right- circularly polarized light. This thesis focuses on the theoretical prediction of this chiroptic property using CC and DFT quantum chemical models. Several small chiral systems have been studied, including (S)-methyloxirane, (R)-epichlorohydrin, (R)-methylthiirane, and the conform...

  • Thesis

  • Authors: Mehmood, Faisal (2006)

  • Ab initio electronic structure calculations based on density functional theory with the generalized gradient approximation and ultrasoft pseudopotentials have been applied to understand the effect of the local environment on the characteristics of chemisorption of selected atoms and molecules on low and high Miller index surfaces of transition metals. In some calculations the full-potential linearized augmented plane wave method was employed for a more accurate description of electronic struc¬ture. On a set of low and high Miller index surfaces of Cu with coordination ranging from 6 to 9 we find a decrease in CO adsorption energy with an increase in the local coordination. This general trend is found to be in qualitative agreement with experiment. The largest binding energy of CO i...

  • Thesis

  • Authors: Shepler, Benjamin C. (2006)

  • Recent measurements in the Arctic troposphere have revealed episodic depletions of mercury during polar sunrise. The depletion events are thought to be the result of reactions between gas phase elemental mercury with reactive halogen species. The goal of this work has been to characterize reactions between mercury and reactive halogen species with accurate ab initio calculations. The main body of the thesis is divided into eight chapters and two appendices with Chapter 1 being an introduction and summary. Chapter 2 discusses the calculation of potential energy curves for the ground and low-lying excited states of the BrC1 molecule. BrC1 is thought to be a major source of photolyzable halogens in the arctic troposphere. In Chapter 3 the characterization of the ground state of HgO ...

  • Luận văn, Luận án (Theses)

  • Authors: Hoang, Thi Thuc;  Advisor: Genoni, Paul (2015)

  • This research investigated whether Vietnam, as an example of a developing country with limited history of academic library cooperation, is able to adopt and successfully develop consortia as a model to improve access to content and the delivery of services. The research used a mixed methods approach in a two-phase sequential research design consisting of a questionnaire and interviews to collect data relevant to addressing the research question: Are library consortia suited as a means of cooperation by Vietnamese academic libraries, and if so how can they be successfully developed and implemented? The findings provide a picture of the current and likely future state of cooperation and consortia among Vietnamese academic libraries, and support the view that they have not as yet adopt...

  • Thesis

  • Authors: Walker, Megon Jarmaine (2006)

  • Understanding molecular interactions is at the core of computational biology and includes problems such as characterizing protein-protein, protein-small molecule, protein-DNA, and Protein-RNA binding events. These interactions are often elucidated by expensive and time-consuming assays during which candidate binders are screened against a target. The main aim of this dissertation is to improve the speed, cost, and overall efficiency of screening assays in the context of drug design and molecular systems biology. Sequential screening is an iterative process of experimentation and model refinement. Target binding activity is determined for samples of putative binders, results are used to update a classification model, and subsequent binding experiments are performed based on knowledg...

  • Thesis

  • Authors: Reck, Gregory M. (2006)

  • While most proteins in biological systems are inherently stable as a prerequisite to performing their functions, a small number of normally well-behaved proteins can engage in a process of aggregation that eventually leads to the formation of an insoluble material identified as an amyloid. Details of the aggregation process are not fully known, but for some model proteins the process can be initiated with known destabilizing conditions. While no sequence or structural similarities have been observed among the proteins, structural instability associated with a characteristic motif in the protein could be a common thread. The proposed strategy to search for such a feature employs a knowledge-based tool that examines the sequence-structure relationship in a specific target protein base...

  • Thesis

  • Authors: Gu, Zhenmei (2006)

  • As text-based resources available online continue to grow explosively, there is ever-increasing need for automatically extracting useful information from these textual data. Information Extraction (IE) is the problem of extracting specific information from textual documents for generating structured summaries. The research in IE has evolved from the IE systems that were manually built with hand-crafted rules, to more recent ones that obtain extraction knowledge automatically from annotated texts. The advantage of using machine learning is that it is easier to adapt an IE system to different extraction tasks. Such adapt-ability is a key requirement for practical IE systems. In view of these, in this thesis we focus our work on the IE systems that can learn extraction knowledge from d...

  • Thesis

  • Authors: Gowing, Glyn Thomas (2007)

  • Computer networks continue to be the targets of numerous types of attacks, which can expose sensitive data or simply deny service to legitimate users. Current intrusion detection technologies utilize signature bases that allow them to rapidly and accurately identify known attacks. This, however, leaves them vulnerable to previously unknown attacks. An adaptive approach, capable of recognizing novel attacks, is warranted. The proposed research presents an adaptive agent-based intrusion detection sys¬tem. The approach is innovative in several respects: the agents self-organize into a scale-free peer-to-peer network, emergent behavior is facilitated by allowing simple communication between the agents, and the system is adaptive both to recognize new attacks and to the loss of agents, ...