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    Showing results [271 - 290] / 1659
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    • Thesis

    • Authors: Bartley, Katherine (2006)

    • Algebraic geometric codes over rings were defined and studied in the late 1990's by Walker, but no decoding algorithm was given. In this dissertation, we present three decoding algorithms for algebraic geometric codes over rings. The first algorithm presented is a modification of the basic algorithm for algebraic geometric codes over fields, and decodes with respect to the Hamming weight. The second algorithm presented is a modification of the Guruswami-Sudan algorithm, a list decoding algorithm for one-point algebraic geometric codes over fields. This algorithm also decodes with respect to the Hamming weight. Finally, we show how the Koetter-Vardy algorithm, a soft-decision decoding...

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    • Thesis

    • Authors: Bhargava, Ankur (2006)

    • The dissertation introduces new tools to derandomize algorithms. These tools find application in derandomizing most approximation algorithms that are based on semidefinite optimization. We also apply these tools to construct deterministic embeddings for dimensionality reduction. These techniques give new ways to approx¬imate conditional probabilities with bounded error and ways to bound conditional probabilities with new pessimistic estimator functions. These ideas are more gener¬ally applicable and not limited to the problems that they are applied to here. In applying some of these new ideas we give a fast deterministic algorithm for the Maximum cut problem. This algorithm gives the...

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    • Thesis

    • Authors: Nguyễn, Quang Nam. (2009)

    • This thesis describes the development of novel high-frequency (>150 kHz) matrix converters for induction heating applications. The primary goal has been to explore the possibility of making high performance direct converters, allowing more compact and reliable power converters to be realised, by removing the bulky energy storage components of the DC-link found in traditional approaches. High input power quality, i.e. unity input power factor and very low input total harmonic distortion (THD), and good efficiency are demanded. A single-phase matrix converter has been developed to firstly explore the possibility of performing high speed commutation of output current, without any DC-li...

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    • Thesis

    • Authors: Helms, Brett Anthony (2006)

    • Polymers have been broadly applied in synthesis applications for decades in part due to their macromolecular nature, which facilitates product recovery, and their multivalency, which enables high loading. Both heterogeneous and homogeneous polymer supported reagents, catalysts, scavengers, etc. are known and have widespread use in industry for the production of fine chemicals. It was clear, however, from the onset of their implementation in chemical synthesis that functional polymers displayed unique behavior in solution that was not observed for their small molecule counterparts. In fact, the reactivity of moieties bound to the support was regulated by steric accessibility, mircoenvi...

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    • Thesis

    • Authors: Murphy, Amanda Ruth (2006)

    • In the past ten years, much progress has been made in producing organic semiconductors with properties that rival amorphous silicon. Organic semiconductors are sought for low-cost or large-area electronic devices such as organic field-effect transistors (OFETs), light-emitting diodes (OLEDs), photovoltaic cells, sensors, and radio frequency identification (RFID) tags. Low temperature processing options and the ductility of organic materials also allow flexible plastics or fabrics to be used as substrates. However, the majority of the newly developed materials are insoluble requiring the use of thermal evaporation to obtain thin films. In order for these organic semiconductors to compe...

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    • Thesis

    • Authors: Gayed, Ramez Botros (2006)

    • Experimental and numerical studies were carried out to investigate the punching shear strength of post-tensioned concrete flat slab-interior column connections under the effects of gravity loads and lateral displacements induced by earthquakes. Seven full-size post-tensioned slab-interior column connections were tested under gravity loads combined with cyclic displacement reversals of increasing amplitude up to failure. The ratio of prestressed to non-prestressed reinforcement was varied, while the flexural strength was constant. The slabs were reinforced with headed studs, a type of shear reinforcement that had been developed at the University of Calgary. The objective of this experi...

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    • Thesis

    • Authors: Hu, Changhong (2006)

    • Ultrasound imaging is a well-established and widely used clinical technique that shows the cross-sectional image of human tissues. Conventional ultrasound systems are targeted at imaging the heart or abdominal organs and the spatial resolution at this frequency range is on the order of a few millimeter. An ultrasound system will be capable of providing a better spatial resolution if higher frequencies are used. High frequency ultrasonic imaging (> 20 MHz) using single element transducers has been shown to be clinically useful in ophthalmology, dermatology, small animal and intravascular imaging. In recent years, more studies have been carried out on the development of high frequency a...

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    • Thesis

    • Authors: Lin, Li (2005)

    • Curcumin is the major yellow pigment isolated from the rhizome of Curcuma longa, known as turmeric. Over a long period of study, curcumin has been found to possess a wide range of bioactivities including anti-prostate cancer activity in vitro and in vivo. Based on these observations, our laboratory has been using curcumin as the lead compound to develop various analogs as potential anti-prostate cancer agents. Two curcumin analogs, dimethyl curcumin (DMC, 4) and 4-ethoxycarbonylethyl curcumin (ECECur, 5) developed previously were found to be active anti-androgen receptor agents, which showed greater potency than hydroxyflutamide, an anti-androgen currently used clinically. However, th...

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    • Thesis

    • Authors: Fan, Li-juan (2006)

    • This dissertation explores the synthesis, characterization, and application of conjugated polymers as fluorescence “turn-on” chemosensors. A series of conjugated polymers using the poly[p-(phenyleneethynelene)-alt-(thienylene-ethylene)](PPETE) polymer backbone were prepared using N,N-diethylamino (dea) and N,N,N’-trimethylethylenediamino (tmeda) groups as receptors. The conjugated polymers were designed as fluorescence “turn-on” chemosensors based on a photoinduced electron transfer (PET) mechanism in which the polymer fluorescence is quenched in the absence of coordinating analytes. A chelation-enhanced fluorescence (CHEF) phenomenon results upon coordination of a cation to the redox...

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    • Thesis

    • Authors: Siles, Rogelio (2006)

    • In an effort to combat cancer, the development of a relatively new type of anti-cancer drugs known as vascular disrupting agents (VDAs) seems to be a promising clinical approach. VDAs selectively interfere with blood flow in the microvessels that carry nutrients and oxygen to the tumor. Blockage of these vessels will stop tumor growth, produce necrosis, and hence prevent proliferation of cancer cells through the body. The discovery of a group of VDAs known as combretastatins (CA) has sparked an exciting area of anti-cancer drug discovery due to their robust biological activity as evidenced through clinical success, particularly for combretastatin A-4 phosphate (CA-4P) and one nitrogen...

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    • Thesis

    • Authors: Welna, Daniel Thomas (2006)

    • The work described in this thesis focuses on the design, synthesis, and characterization of polymeric materials for energy storage applications, which include small molecule electrolyte additives, solid polymer electrolyte, and gel polymer electrolyte systems. In addition, non-woven nanofiberous mats of a pre-ceramic polymer were examined for high-strength and temperature material applications. Chapter 2 of this thesis describes the synthesis of novel polyphosphazene single ion conductors for use in secondary lithium ion batteries. Chapters 3 and 4 details work towards the synthesis and evaluation of highly selective membranes for use in lithium-seawater batteries. The fifth chapter d...

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    • Thesis

    • Authors: Jiang, Jinyue (2006)

    • The practical uses of pentacene, the most promising polyacene in the area of organic field-effect transistors, are limited by its sensitivity to oxygen and poor solubility in organic solvents. To overcome these disadvantages, new organic semiconductors, 2,3,6,9, 10,13 -hexa(trimethylsily lethynyl)pentacene, 2,3,9,10-tetrakis(triisopropylsilylethynyl)-6,13-bis(trimethylsilylethynyl)pentacene, and 2,3,9,10-tetrakis(3,5-di-t-butylphenylethynyl)-6,13-bis(trimethylsilylethynyl)pentacene were designed, synthesized, and fully characterized. In comparison with pentacene, they are stable and soluble and have extended 7t-conjugation. Each demonstrates reduction potentials that are essentially ...

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    • Thesis

    • Authors: Chen, Wei (2005)

    • Well coordinated behaviors greatly improve intelligent entities overall performance, while inappropriate coordination results in reduced system efficiency, unfinished core tasks, misuse of key resources, and even system crashes. Thus, coordination is a central research task in Distributed Artificial Intelligence (DAI). This dissertation discusses our way of approaching the coordination problem, which is to develop an extended set of coordination mechanisms to manage the inter-dependencies between the activities among multiple agents. This dissertation presents four steps to tackle this problem. First, formal representation: articulating a domain-independent approach for specifying a...

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    • Thesis

    • Authors: Baker, Ryan Shaun (2006)

    • Students use intelligent tutors and other types of interactive learning environments in a considerable variety of ways. In this thesis, I detail my work to understand, automatically detect, and re-design an intelligent tutoring system to adapt to a behavior I term "gaming the system". Students who game the system attempt to succeed in the learning environment by exploiting properties of the system rather than by learning the material and trying to use that knowledge to answer correctly. Within this thesis, I present a set of studies aimed towards understanding what effects gaming has on learning, and why students game, using a combination of quantitative classroom observations and ...

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    • Thesis

    • Authors: Escuadro, Henry E. (2006)

    • A basic problem in graph theory is to distinguish the vertices of a connected graph from one another in some manner. In this study, we investigate the problem of coloring the edges of a graph in a manner that distinguishes the vertices of the graph. The method we use combines many of the features of previously introduced methods. Let G be a connected graph of order n > 3 and let c : E(G) -+ {1, 2, ... , k} be a coloring of the edges of G (where adjacent edges may be colored the same). For each vertex v of G, the color code of v with respect to c is the k-tuple c(v) = (al, a2i ... , ak), where a, is the number of edges incident with v that are colored i (1 < i < k). The coloring c is ...