Physical Sciences and Mathematics Commons^™

Availability Modeling And Evaluation On High Performance Cluster Computing Systems, Hertong Song

Doctoral Dissertations

Cluster computing has been attracting more and more attention from both the industrial and the academic world for its enormous computing power, cost effective, and scalability. Beowulf type cluster, for example, is a typical High Performance Computing (HPC) cluster system. Availability, as a key attribute of the system, needs to be considered at the system design stage and monitored at mission time. Moreover, system monitoring is a must to help identify the defects and ensure the system's availability requirement.

In this study, novel solutions which provide availability modeling, model evaluation, and data analysis as a single framework have been investigated. …

Evaluating Online Trust Using Machine Learning Methods, Weihua Song

Doctoral Dissertations

Trust plays an important role in e-commerce, P2P networks, and information filtering. Current challenges in trust evaluations include: (1) fnding trustworthy recommenders, (2) aggregating heterogeneous trust recommendations of different trust standards based on correlated observations and different evaluation processes, and (3) managing efficiently large trust systems where users may be sparsely connected and have multiple local reputations. The purpose of this dissertation is to provide solutions to these three challenges by applying ordered depth-first search, neural network, and hidden Markov model techniques. It designs an opinion filtered recommendation trust model to derive personal trust from heterogeneous recommendations; develops a reputation …

The Bipartite Clique: A Topological Paradigm For Web User Search Customization And Web Site Restructuring, Brenda F. Choyce-Miles

Doctoral Dissertations

The objective of this dissertation research is to aid the Web user to achieve his search objective at a host Web site by organizing a strongly connected neighborhood of Web pages that are thematically and spatially related to the user's search interest. Therefore, methods were developed to (1) find all Web pages at a given Web site that are thematically similar to a user's initial choice of a Web page (selected from the set of Web pages returned in response to a query by any popular search engine), and (2) organize these pages hierarchically in terms of their relevance to …

Developing A B -Tagging Algorithm Using Soft Muons At Level-3 For The Dø Detector At Fermilab, Mayukh Das

Doctoral Dissertations

The current data-taking phase of the DØ detector at Fermilab, called Run II, is designed to aid the search for the Higgs Boson. The neutral Higgs is postulated to have a mass of 117 GeV. One of the channels promising the presence of this hypothetical particle is through the decay of b-quark into a muon. The process of identifying a b-quark in a jet using muon as a reference is b-tagging with a muon tag.

At the current data taking and analysis rate, it will take long to reach the process of identifying valid events. The triggering mechanism of the …

Integrated Modeling And Parallel Computation Of Laser-Induced Axisymmetric Rod Growth, Hong Lan

Doctoral Dissertations

To fully investigate a pyrolytic Laser-induced chemical vapor deposition (LCVD) system for growing an axisymmetric rod, a novel integrated three-dimensional mathematical model was developed not only to describe the heat transport in the deposit and substrate, but also to simulate the gas-phase in the heated reaction zone and its effect on growth rate. The integrated model consists of three components: the substrate, rod, and gas-phase domains. Each component is a separate model and the three components are dynamically integrated into one model for simulating the iterative and complex process of rod deposition.

The gas-phase reaction is modeled by the gas-phase …