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sheikh, Umair. "Analysis of Power System Stability by Using Optimally Located SVC and STATCOM." Thesis, KTH, Elektriska energisystem, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119248.
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Ahmed, Sheikh. "PMU based PSS and SVC fuzzy controller design for angular stability analysis." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20547.
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Master of ScienceDepartment of Electrical and Computer Engineering
Shelli Starrett
Variability in power systems is increasing due to pushing the system to limits for economic purposes, the inclusion of new energy sources like wind turbines and photovoltaic, and the introduction of new types of loads such as electric vehicle chargers. In this new environment, system monitoring and control must keep pace to insure system stability and reliability on a wide area scale. Phasor measurement unit technology implementation is growing and can be used to provide input signals to new types of control. Fuzzy logic based power system stabilizer (PSS) controllers have also been shown effective in various studies. This thesis considers several choices of input signals, composed assuming phasor measurement availability, for fuzzy logic-based controllers. The purpose of the controller is to damp power systems’ low frequency oscillations. Nonlinear transient simulation results for a 4-machine two-area system and 50 machine system are used to compare the effects of input choice and controller type on damping of system oscillations. Reactive power in the system affects voltage, which in turn affects system damping and dynamic stability. System stability and damping can be enhanced by deploying SVC controllers properly. Different types of power system variables play critical role to damp power swings using SVC controller. A fuzzy logic based static var compensator (SVC) was used near a generator to damp these electromechanical oscillations using different PMU-acquired inputs. The goal was again improve dynamic stability and damping performance of the system at local and global level. Nonlinear simulations were run to compare the damping performance of different inputs on the 50 machine system.
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Fellah, Clémentine. "Influence de la nature des interfaces carbonées au sein des composites SiC/SiC à renfort Hi-Nicalon S et Tyranno SA3 sur leur comportement mécanique." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM078.
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Les composites SiC/SiC à interphase pyrocarbone (PyC) sont des candidats prometteurs en tant que matériau de gainage du combustible et de structure des réacteurs à neutrons rapides, constituant une alternative aux alliages métalliques. Leur comportement sous irradiation neutronique et leur caractère réfractaire sont de sérieux atouts en milieu irradiant. Néanmoins, les fibres et la matrice en carbure de silicium (SiC) sont, individuellement, des céramiques fragiles. L’intégrité des structures ne peut donc être assurée que si le composite acquiert une tolérance aux déformations. Cette tolérance n’est possible que grâce à la présence d’une interphase de pyrocarbone, entre la matrice et les fibres, assurant le rôle de déviateur de fissures. La capacité des composites SiC/SiC à résister à l’endommagement est dictée par le couplage fibre/matrice (F/M). L’intensité de ce couplage peut être influencée par de nombreux paramètres, tels que la rugosité et la physicochimie de surface du renfort. Les travaux faisant l’objet de cette thèse ont mis en évidence une couche de carbone en surface des fibres par microscopie électronique en transmission à haute résolution (METHR) et via des analyses physicochimiques de surface. Les caractéristiques de cette couche de carbone varient avec le procédé de fabrication des fibres. Son impact sur le couplage F/M a été appréhendé par l’observation des mécanismes locaux d’endommagement. La décohésion fibre/matrice a été étudiée en analysant par METHR les régions interfaciales des composites SiC/SiC ayant subi un essai mécanique. La compréhension de l’origine de cette couche de surface de fibres a permis de mieux connaitre les mécanismes locaux d’interaction. Ces mécanismes dépendent de la structure du carbone de surface des fibres dont découle le mode d’adhésion entre ce carbone de surface et l’interphase de pyrocarbone. Un traitement de surface sur un type de fibres a alors été développé, suggérant une légère amélioration du comportement mécanique des composites SiC/SiC élaborés à partir de ces renforts fibreuxSiC/SiC composites including the third generation SiC fibers with pyrocarbon interphase (PyC) are promising candidates to improve the safety of nuclear reactors, especially for core materials such as cladding and to replace metallic alloys for these applications. Their intrinsic refractory properties, their neutron transparency and their microstructural stability when irradiated or exposed to high temperatures make them attractive for nuclear applications. However SiC fibers and SiC matrix are brittle ceramics. The integrity of the structures can be fulfilled only if the composite is damage tolerant and can acquire a pseudo-ductile mechanical behavior. An interphase is deposited between the fibers and the matrix to provide this damage tolerance of SiC/SiC composites.The ability of SiC/SiC composites to sustain damage is dictated by the fiber/matrix (F/M) coupling mode. The intensity of this coupling can be related to many parameters such as the roughness and the chemistry of the surface of the reinforcement. A carbon layer on the fiberssurface was highlighted by High Resolution Transmission Electronic Microscopy (HRTEM) and by physico-chemical analyses. The characteristics of this carbon layer vary with the fabrication process of the fibers. The impact of this carbon layer on the F/M coupling was investigated by the observation of the local damage mechanisms. To elucidate the local bonding modes governing the damage mechanisms at the F/M interface of these SiC/SiC composites, macroscopic mechanical tests have been coupled with observations of structural modifications occurring in the interface region after loading. Understanding the origin of this carbon layer allowed elucidating the local interaction mechanisms according to these studied materials. These mechanisms depend on the carbon structure of the SiC fibers surface which in turn governs the adhesion between this carbon and the PyC interphase. Thanks to this study, a surface treatment on fibers was developed to optimize the mechanical behavior of SiC/SiC composites, whatever the fibrous reinforcement chosen
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Medová, Alena. "Analýza aplikace statistických metod v podniku AFL Stříbro. Porovnání s požadavky VDA." Master's thesis, Vysoká škola ekonomická v Praze, 2007. http://www.nusl.cz/ntk/nusl-3851.
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Vaughn, Alexis. "How can we grow if we destroy our roots? An analysis of roots as metaphor for growth and urban change." Scripps College, 2010. http://ccdl.libraries.claremont.edu/u?/stc,88.
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Roots: They take hold; they grow, expand and change, creating networks and sub-networks as they start to break above the earth's surface and stretch up higher towards the sky day by day. Roots can be taken out (the stock, stem or trunk removed), but both the memory and the evidence of the roots' existence will continue to remain for a while to come. The idea of "roots" applies to so much: from artists taking inspiration from previous artists, even at times to mirror the change in the world which one artist had previously documented; from the places we establish our families and create our memories, to a good deal more.
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Vase, Ajoy. "The effects of material treatments on the surface properties of polymeric biomaterials." Pomona College, 2007. http://ccdl.libraries.claremont.edu/u?/stc,19.
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This work examines the chemical and physical effects of a material treatment process on the biopolymers PEEK, POM-h, POM-c, PTFE and UHMWPE. The polymers are analyzed physically and chemically using atomic force microscopy, profilometry, scanning electron microscopy, optical microscopy, contact angle measurement, FT infra-red spectroscopy and energy dispersive X-ray spectrometry. PEEK is found to be the most suitable polymer and FT Infra-red spectroscopy an informative analytic tool.
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DiMarino, Christina Marie. "High Temperature Characterization and Analysis of Silicon Carbide (SiC) Power Semiconductor Transistors." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/78116.
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This thesis provides insight into state-of-the-art 1.2 kV silicon carbide (SiC) power semiconductor transistors, including the MOSFET, BJT, SJT, and normally-on and normally-off JFETs. Both commercial and sample devices from the semiconductor industry's well-known manufacturers were evaluated in this study. These manufacturers include: Cree Inc., ROHM Semiconductor, General Electric, Fairchild Semiconductor, GeneSiC Semiconductor, Infineon Technologies, and SemiSouth Laboratories. To carry out this work, static characterization of each device was performed from 25 ºC to 200 ºC. Dynamic characterization was also conducted through double-pulse tests. Accordingly, this thesis describes the experimental setup used and the different measurements conducted, which comprise: threshold voltage, transconductance, current gain, specific on-resistance, parasitic capacitances, internal gate resistance, and the turn on and turn off switching times and energies. For the latter, the driving method used for each device is described in detail. Furthermore, for the devices that require on-state dc currents, driving losses are taken into consideration. While all of the SiC transistors characterized in this thesis demonstrated low specific on-resistances, the SiC BJT showed the lowest, with Fairchild's FSICBH057A120 SiC BJT having 3.6 mΩ•cm2 (using die area) at 25 ºC. However, the on-resistance of GE's SiC MOSFET proved to have the smallest temperature dependency, increasing by only 59 % from 25 ºC to 200 ºC. From the dynamic characterization, it was shown that Cree's C2M0080120D second generation SiC MOSFET achieved dv/dt rates of 57 V/ns. The SiC MOSFETs also featured low turn off switching energy losses, which were typically less than 70 µJ at 600 V bus voltage and 20 A load current.Master of Science
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Rios, Mario Alberto. "Modélisation pour analyses dynamiques des réseaux électriques avec compensateurs de puissance réactive-SVC." Grenoble INPG, 1998. http://www.theses.fr/1998INPG0099.
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Cette Thèse traite de la modélisation des réseaux électriques comportant des compensateurs statiques de puissance réactive (SVC). La modélisation est basée sur des modèles d'ordre réduit utilisant la réduction par troncature des valeurs singulières de Hankel et l'identification dynamique N4Sid. Pour le cas de réseaux comportant plusieurs SVC ou composants FACTS (Flexible AC Transmission Systems), on a proposé une structure de modélisation par sous-systèmes calculée par des techniques d'ordre réduit. Ces modèles réduits permettent de calculer des lois de commande type LQG (Linear Quadratic Gaussian Regulator) et des commandes robustes d'ordre réduit qui ont des performances supérieures par rapport aux correcteurs traditionnels des SVC (commande proportionnelle). Avec la structure en sous-systèmes, on a proposé des méthodes de calcul des correcteurs décentralisés appliqués aux réseaux électriques. D'autre part, on a proposé une technique d'analyse de la robustesse des réseaux en utilisant la théorie d'analyse des valeurs singulières structurées, permettant de déterminer les frontières de stabilité basées en le calcul des fonctions de transfert de l'ensemble système-commande. Les différentes techniques développées dans le cadre de cette thèse sont appliquées à un réseau test de 11 nœuds et à un grand réseau électrique et donnent des résultats très satisfaisantsThis thesis studies the modeling and analysis of power System containing static VAR compensators (SVC). Low-order models, calculated by Hankel singular-value truncation réduction and N4Sid dynamic identification, provide the foundation for the modeling and analysis techniques. For cases where many SVCs or FACTS (Flexible AC Transmission Systems) devices are installed in a power System, a new subsystem structure based on thèse low-order modeling techniques has been developed. The proposed low-order models allow the computation of low-order LQG-type (Linear Quadratic Gaussian Regulator) control laws, as well as low-order robust controls, which provide a better performance relative to traditional SVC controls (proportional type). Using the subsystem structure formulated in this thesis, methods for calculating decentralized controllers for power Systems hâve been conceived. In addition, through the use of structured singular values, a new robustness analysis technique has been developed which allows the détermination of stability boundaries through the calculation of closed-loop transfer functions. The theoretical approaches in this work hâve been applied to a test power system containing 11 nodes, as well as a larger 173-node test system
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Wong, Lilly. "Conformational analysis of C-terminal Src kinase /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3153687.
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Tvedt, Valerie Maria. "Some factors that effect [sic] statistical power in ANCOVA: a population study." CSUSB ScholarWorks, 2000. https://scholarworks.lib.csusb.edu/etd-project/1764.
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A study into the factors that affect power in an analysis of covariance (ANCOVA) design were examined. Four factors - sample size, significance level, dependent variable-covariate correlations and homogeneity of regression - were varied in a population study. Results indicate that power increased when the dependent variable-covariate correlations increased and when sample size increased. Power also increased when a less stringent alpha level was used. Homogeneity of regression did not effect power. Implications and recommendations for the applied researcher are discussed.
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Renkjumnong, Wasuta. "SVD and PCA in Image Processing." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/math_theses/31.
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The Singular Value Decomposition is one of the most useful matrix factorizations in applied linear algebra, the Principal Component Analysis has been called one of the most valuable results of applied linear algebra. How and why principal component analysis is intimately related to the technique of singular value decomposition is shown. Their properties and applications are described. Assumptions behind this techniques as well as possible extensions to overcome these limitations are considered. This understanding leads to the real world applications, in particular, image processing of neurons. Noise reduction, and edge detection of neuron images are investigated.
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Feng, Xiaohu. "SIC BASED SOLID STATE POWER CONTROLLER." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/543.
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The latest generation of fighter aircraft utilizes a 270Vdc power system [1]. Such high voltage DC power systems are difficult to protect with conventional circuit breakers because the current does not automatically go to zero twice per cycle during a fault like it does in an AC power system and thus arcing of the contacts is a problem. Solid state power controllers (SSPCs) are the solid state equivalent of a circuit breaker that do not arc and which can respond more rapidly to a fault than a mechanical breaker [2]. Present SSPCs are limited to lower voltages and currents by the available power semiconductors [8,9]. This dissertation presents design and experimental results for a SSPC that utilizes SiC power JFETs for the SSPC power switch to extend SSPC capability to higher voltages and currents in a space that is smaller than what is practically achievable with a Si power switch. The research started with the thermal analysis of the SSPCs power switch, which will guide the development of a SiC JFET multi-chip power module to be fabricated by Solid State Devices Inc. (SSDI) using JFETs from SiCED and/or Semisouth LLC. Multiple multi-chip power modules will be paralleled to make the SSPC switch. Fabricated devices were evaluated thermally both statically and dynamically and electrically both statically and dynamically. In addition to the SiC module research a detailed design of the high voltage SSPC control circuit capable of operating at 200andamp;ordm;C was completed including detailed analysis, modeling and simulations, detailed schematic diagrams and detailed drawings. Finally breadboards of selected control circuits were fabricated and tested to verify simulation results. Methods for testing SiC JFET devices under transient thermal conditions unique to the SSPC application was also developed.
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MISHRA, OM. "HUMAN MOTION ANALYSIS." Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2020. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18772.
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Human motion analysis in the video has its vast application. The recognition of the human action is the most prominent application of human motion analysis. In this research we analyzed different methodologies for modeling human action. We also discussed challenges and methodologies which are used to handle them. These methodologies are divided into two categories. One is global feature descriptor and other is local feature descriptors. The disadvantage of the global feature descriptor is that they can only give the shape information but fails to give motion information. The local feature descriptors are used to find out the motion information of the action video. The disadvantage is that it cannot give the shape or structure information of the action video. The hybrid descriptors are used to solve these problems but these descriptors suffer from high dimensionality features. In this research we proposed new feature descriptors which are capable to deal with these issues in the following manner:
1) We proposed a new local descriptor evaluated from the Finite Element Analysis for human action recognition. This local descriptor represents the distinctive human poses in the form of the stiffness matrix. This stiffness matrix gives the information of motion as well as shape change of the human body while performing an action. Initially, the human body is represented in the silhouette form. Most prominent points of the silhouette are then selected. This silhouette is discretized into several finite small triangle faces (elements) where the prominent points of the boundaries are the vertices of the triangles. The stiffness matrix of each triangle is then calculated. The feature vector representing the action video
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frame is constructed by combining all stiffness matrices of all possible triangles. These feature vectors are given to the Radial Basis Function-Support Vector Machine (RBF-SVM) classifier. The proposed method shows its superiority over other existing state-of-the-art methods on the challenging datasets Weizmann, KTH, Ballet, and IXMAS.
2) Background cluttering, appearance change due to variation in viewpoint and occlusion are the prominent hurdles that can reduce the recognition rate significantly. Methodologies based on Bag-of-visual-words are very popular because they do not require accurate background subtraction. But the main disadvantage with these methods is that they do not retain the geometrical structural information of the clusters that they form. As a result, they show intra-class mismatching. Furthermore, these methods are very sensitive to noise. Addition of noise in the cluster also results in the misclassification of the action. To overcome these problems we proposed a new approach based on modified Bag-of-visual-word. Proposed methodology retains the geometrical structural information of the cluster based on the calculation of contextual distance among the points of the cluster. Normally contextual distance based on Euclidean measure cannot deal with the noise but in the proposed methodology contextual distance is calculated on the basis of a difference between the contributions of cluster points to maintain its geometrical structure. Later directed graphs of all clusters are formed and these directed graphs are described by the Laplacian. Then the feature vectors representing Laplacian are fed to the Radial Basis Function based Support Vector Machine (RBF-SVM) classifier.
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3) We also proposed a new feature descriptor to detect abnormality in a video captured for surveillance applications in real-time and also overcome the problem of the curse of dimensionality. To extract features related to any change in the video, non linear Gaussian fuzzy lattice functions have been applied on each frame of the video which results in the formation of fuzzy lattices. These fuzzy lattices have been expressed in the form of Schrödinger equation to find the kinetic energy involved corresponding to any change in the video. A number of the fuzzy lattice has been used as a dimension of the feature. It reduces the dimensionality significantly as compared to other state-of-the-art methods. Finally, the kinetic energy parameter is classified into normal and abnormal activities with the help of SVM-based classifier.
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Moos, Sarah. "Analyzing the interconnectedness between space, place, and human interaction with the natural environment: "Ecological reawakening: Organic DNA and evolution"." Scripps College, 2009. http://ccdl.libraries.claremont.edu/u?/stc,51.
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I have organized this paper into four chapters: "The Environmental Situation," "Space and Place," "Art and the Natural Environment," and "Creating Work of My Own." Chapter 1 explains human beings' intrinsic interconnection to the natural environment, outlining why humans should be concerned about the current degraded state of the natural world. Chapter 2 discusses the concepts of space and place. It analyzes how human beings interact with and experience spaces, developing their sense of place - within physical, theoretical, and spiritual realms. It finally illustrates the importance that spaces and places have in humans' lives. Chapter 3 describes the Land Art phenomenon: its development, the different forms within it, and artists producing Land Artworks. The forms and artists included are those that have been inspirational for the development of my own work. It also emphasizes Land Art as a fundamental form for improving humans' relationship with the natural environment and the new realm of eco-feminism that resonates with Land Art ideals. Chapter 4 recounts the development of my art throughout my college career. It describes my work as site-specific, sculptural installations that use natural materials. It also states why this format is the most effective for my senior art thesis project. Focusing mainly on "Ecological Reawakening: organic DNA," it explains the mentality in designing, creating, installing, and completing the work. Overall, Chapter 4 emphasizes the work's two main goals: to demonstrate a new avenue for comprehending humankind's place within earth's environmental spaces, and to advocate for an environmental paradigm shift during the twenty-first century. Finally, Chapter 5 describes the transformation of "Ecological Reawakening: organic DNA" as it developed over time during the spring honors senior thesis course. It details my mentalities in adding living plant matter to the structure, incorporating a stool into the piece, and creating "Evolution," the digital photography composition that documents "Ecological Reawakening" and was included in the Scripps Senior Art Exhibition in the Ruth Chandler Williamson Gallery from May 1 – May 17, 2009.
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Vase, Ajoy. "The effect of materials preparation on polymer surfaces." Pomona College, 2007. http://ccdl.libraries.claremont.edu/u?/stc,25.
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This work examines the chemical and physical effects of a material treatment process on the biopolymers PEEK, POM-h, POM-c, PTFE and UHMWPE. The polymers are analyzed physically and chemically using atomic force microscopy, profilometry, scanning electron microscopy, optical microscopy, contact angle measurement, FT infra-red spectroscopy and energy dispersive X-ray spectrometry. PEEK is found to be the most suitable polymer and FT Infra-red spectroscopy an informative analytic tool.
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Guan, Wei. "New support vector machine formulations and algorithms with application to biomedical data analysis." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41126.
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The Support Vector Machine (SVM) classifier seeks to find the separating hyperplane wx=r that maximizes the margin distance 1/||w||2^2. It can be formalized as an optimization problem that minimizes the hinge loss Ʃ[subscript i](1-y[subscript i] f(x[subscript i]))₊ plus the L₂-norm of the weight vector. SVM is now a mainstay method of machine learning. The goal of this dissertation work is to solve different biomedical data analysis problems efficiently using extensions of SVM, in which we augment the standard SVM formulation based on the application requirements. The biomedical applications we explore in this thesis include: cancer diagnosis, biomarker discovery, and energy function learning for protein structure prediction.
Ovarian cancer diagnosis is problematic because the disease is typically asymptomatic especially at early stages of progression and/or recurrence. We investigate a sample set consisting of 44 women diagnosed with serous papillary ovarian cancer and 50 healthy women or women with benign conditions. We profile the relative metabolite levels in the patient sera using a high throughput ambient ionization mass spectrometry technique, Direct Analysis in Real Time (DART). We then reduce the diagnostic classification on these metabolic profiles into a functional classification problem and solve it with functional Support Vector Machine (fSVM) method. The assay distinguished between the cancer and control groups with an unprecedented 99\% accuracy (100\% sensitivity, 98\% specificity) under leave-one-out-cross-validation. This approach has significant clinical potential as a cancer diagnostic tool.
High throughput technologies provide simultaneous evaluation of thousands of potential biomarkers to distinguish different patient groups. In order to assist biomarker discovery from these low sample size high dimensional cancer data, we first explore a convex relaxation of the L₀-SVM problem and solve it using mixed-integer programming techniques. We further propose a more efficient L₀-SVM approximation, fractional norm SVM, by replacing the L₂-penalty with L[subscript q]-penalty (q in (0,1)) in the optimization formulation. We solve it through Difference of Convex functions (DC) programming technique. Empirical studies on the synthetic data sets as well as the real-world biomedical data sets support the effectiveness of our proposed L₀-SVM approximation methods over other commonly-used sparse SVM methods such as the L₁-SVM method.
A critical open problem in emph{ab initio} protein folding is protein energy function design. We reduce the problem of learning energy function for extit{ab initio} folding to a standard machine learning problem, learning-to-rank. Based on the application requirements, we constrain the reduced ranking problem with non-negative weights and develop two efficient algorithms for non-negativity constrained SVM optimization. We conduct the empirical study on an energy data set for random conformations of 171 proteins that falls into the {it ab initio} folding class. We compare our approach with the optimization approach used in protein structure prediction tool, TASSER. Numerical results indicate that our approach was able to learn energy functions with improved rank statistics (evaluated by pairwise agreement) as well as improved correlation between the total energy and structural dissimilarity.
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Mi, Jian. "SiC Growth by Laser CVD and Process Analysis." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-04062006-135055/.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006.Lackey, W. Jack, Committee Chair ; Cochran, Joe K., Committee Member ; Danyluk, Steven, Committee Member ; Fedorov, Andrei G., Committee Member ; Rosen, David W., Committee Member ; Wang, Zhonglin, Committee Member.
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Olivier, Ezra Jacobus. "Analysis of the extended defects in 3C-SiC." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/730.
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The dissertation focuses on the analysis of the extended defects present in as-grown and proton bombarded β-SiC (annealed and unannealed) grown by chemical vapour deposition (CVD) on (001) Si. The proton irradiation was done to a dose of 2.8 × 1016 protons/cm2 and the annealing took place at 1300°C and 1600°C for 1hr. The main techniques used for the analysis were transmission electron microscopy (TEM) and high resolution TEM (HRTEM). From the diffraction study of the material the phase of the SiC was confirmed to be the cubic beta phase with the zinc-blende structure. The main defects found in the β- SiC were stacking faults (SFs) with their associated partial dislocations and microtwins. The SFs were uniformly distributed throughout the foil. The SFs were identified as having a fault vector of the type 1/3 <111> with bonding partial dislocations of the type 1/6 <121> by using image simulation. The SFs were also found to be predominantly extrinsic in nature by using HRTEM analysis of SFs viewed edge-on. Also both bright and dar-field images of SFs on inclined planes exhibited symmetrical and complementary fringe contrast images. This is a result of the anomalous absorption ratio of SiC lying between that of Si and diamond. The analysis of the annealed and unannealed irradiated β-SiC yielded no evidence of radiation damage or change in the crystal structure of the β-SiC. This confirmed that β-SiC is a radiation resistant material. The critical proton dose for the creation of small dislocation loops seems to be higher than for other compound semiconductors with the zinc-blende structure.
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Moghraby, Jeelan Salah. "Analysis of the human Spr18 SMC-like protein." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368280.
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Bandara, Mikaila Jayaweera. "Analysis of the accessory Sec systems in streptococcus." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.688219.
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The bulk of protein secretion in bacteria occurs through the general secretion (Sec) pathway. Proteins interact via their N-terminal leader peptides with the membrane-associated Sec system where they undergo processing, secretion and folding within the cell wall environment. Some Gram-positive bacteria and mycobacteria have been shown to possess a second Sec pathway known as the accessory Sec system. This exports proteins with specific N-terminalleader peptides and assists in the secretion of other proteins that lack N-terminal leaders. The core component of this system is SecA'2, a functional homologue of SecA in the canonical system. Other core components include SecY2 (homologue of SecY) and accessory Sec proteins Asp l-Asp5. The objective of this study was to characterise the composition and activities of the accessory Sec systems in commensal Streptococcus gordonii and pathogenic Streptococcus pneumoniae.
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Pandey, Vinayak. "Quasi-Static and Creep Behavior of Enhanced SIC/SIC Ceramic Matrix Composites." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/33959.
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Continuous Fiber Reinforced Ceramic Composites (CFCC's) are being currently investigated as potential materials for high temperature applications such as combustor liners in stationary gas turbines. The creep behavior of woven Enhanced SiC/SiC composites was studied at temperatures from 600 to 1200 °C and at 140 to 220 MPa stress levels. Most researchers studying the creep behavior of ceramic matrix composites (CMCs) use the time hardening model and rate equations for expressing the dependence of creep strain on time, temperature and stress. Such laws, although simple and easy to use, are inadequate to represent the creep behavior over a range of stress levels and temperatures and cannot be used to quantify the pest phenomenon commonly observed in CMCs. Hence, these laws were modified to include the pest phenomenon and an empirical equation was developed that can be used to represent the creep behavior at various stresses and temperatures. The modified equation was used in the finite element analysis and the results were compared with the time and strain hardening models. Microscopic observations on the fractured surfaces revealed the pseudo-ductile behavior of the material at high temperatures. A quasi-static test was conducted at 1200 °C to determine the unloading response of the material. The stress-strain response of the composite demonstrates a hysterisis loop and a small amount of permanent strain, which are characteristic of the CMC's [3]. Finally, a test was
conducted at 1200 oC to investigate the recovery behavior of the material. The material exhibits a tendency to recover the accumulated creep strain as well as the small permanent strain upon unloading, if sufficient time is allowed for recovery.
The creep data were also modeled using the representations such as Monkmon-Grant and Larsen-Miller equations. A modified Monkman-Grant equation was used to model the stratification of the creep strain rate data with temperature. A finite element model based on the plasticity theory was developed to simulate the quasi-static cyclic behavior of the material. Though the loading behavior of CMCs can be modeled using the bilinear or multilinear kinematic hardening plasticity models, the unloading behavior as predicted by the models is entirely different from the experimentally observed behavior. Hence, these models were modified to correctly predict the stress-strain behavior. The model, which was input via a user defined subroutine into the ANSYS finite element program uses the concept of state or internal variables to define the unloading portion of the stress-strain curve. The results were compared with the test data and they show very good agreement. The model was then used to predict the stress-strain response of a plate with a notch. The results from the analysis were compared with the experimental data and they show good agreement if average values of strains are considered.
Master of Science
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Vaillancourt, Benoit. "Novel biophysical appliations [sic] of STICS." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111550.
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The object of this thesis is to present two novel applications of Spatiotemporal Image Correlation Spectroscopy (STICS) to biological systems. STICS is a technique which uses the correlations in pixel intensity fluctuations of an image time series, captured under fluorescence microscopy, to measure the speed and direction of a flowing population of fluorescently labeled molecules. The method was first applied to measure the dynamics of transport vesicles inside growing pollen tubes of lily flowers. The measured vector maps allowed to confirm the presence of actin filaments along the periphery of the tubes, as well as the presence of a reverse-fountain pattern in the apical region. In a second set of experiments, STICS was used to measure the retrograde flow of filamentous actin in migrating chick DRG neuronal growth cones. These results serve as proof of principle that STICS can be used to probe the response of the growth cone cytoskeleton to external chemical cues.
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Larsson, Jonatan. "Automatic Test Generation and Mutation Analysis using UPPAAL SMC." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36415.
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Software testing is an important process for ensuring the quality of the software. As the complexity of the software increases, traditional means of manual testing becomes increasingly more complex and time consuming. In most embedded systems, designing software with as few errors as possible is often critical. Resource usage is also of concern for proper behavior because of the very nature of embedded systems. To design reliable and energy-efficient systems, methods are needed to detect hot points of consumption and correct them prior to deployment. To reduce testing effort, Model-based testing can be used which is one testing method that allows for automatic testing of model based systems. Model-based testing has not been investigated extensively for revealing resource usage anomalies in embedded systems. UPPAAL SMC is a statistical model checking tool which can be used to model the system’s resource usage. Currently UPPAAL SMC lacks the support for performing automatic test generation and test selection. In this thesis we provide this support with a framework for automatic test generation and test selection using mutation analysis, a method for minimizing the generated test suite while maximizing the fault coverage and a tool implementing the framework on top of the UPPAAL SMC tool. The thesis also evaluates the framework on a Brake by Wire industrial system. Our results show that we could for a Brake-by-wire system, simulated on a consumer processor with five mutants, in best case find a test case that achieved 100% mutation score within one minute and confidently identify at least one test case that achieved full mutation score within five minutes. The evaluation shows that this framework is applicable and relatively efficient on an industrial system for reducing continues resource usage target testing effort.
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Welham, Melanie J. "Functional and genetic analysis of the v-src oncogene." Thesis, University College London (University of London), 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262020.
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Long, Andrew Edmund. "Cokriging, kernels, and the SVD: Toward better geostatistical analysis." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186892.
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Three forms of multivariate analysis, one very classical and the other two relatively new and little-known, are showcased and enhanced: the first is the Singular Value Decomposition (SVD), which is at the heart of many statistical, and now geostatistical, techniques; the second is the method of Variogram Analysis, which is one way of investigating spatial correlation in one or several variables; and the third is the process of interpolation known as cokriging, a method for optimizing the estimation of multivariate data based on the information provided through variogram analysis. The SVD is described in detail, and it is shown that the SVD can be generalized from its familiar matrix (two-dimensional) case to three, and possibly n, dimensions. This generalization we call the "Tensor SVD" (or TSVD), and we demonstrate useful applications in the field of geostatistics (and indicate ways in which it will be useful in other areas). Applications of the SVD to the tools of geostatistics are described: in particular, applications dependent on the TSVD, including variogram modelling in coregionalization. Variogram analysis in general is explored, and we propose broader use of an old tool (which we call the "corhogram ", based on the variogram) which proves useful in helping one choose variables for multivariate interpolation. The reasoning behind kriging and cokriging is discussed, and a better algorithm for solving the cokriging equations is developed, which results in simultaneous kriging estimates for comparison with those obtained from cokriging. Links from kriging systems to kernel systems are made; discovering kerneIs equivalent to kriging systems will be useful in the case where data are plentiful. Finally, some results of the application of geostatistical techniques to a data set concerning nitrate pollution in the West Salt River Valley of Arizona are described.
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Chen, Yang. "Damage mechanisms in SiC/SiC composite tubes : three-dimensional analysis coupling tomography imaging and numerical simulation." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1056/document.
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Du fait de leurs propriétés physiques et chimiques exceptionnelles à haute température par rapport aux métaux, les composites de carbure de silicium (SiC) sont étudiés comme éventuel matériau de gainage du combustible nucléaire dans les réacteurs de fusion ou fission avancée futurs, ainsi que, depuis plus récemment, dans les réacteurs à eau légère existants. Les tubes composites SiC/SiC tressés en 2D, fabriqués par procédé d'infiltration chimique en phase vapeur (CVI), présentent un comportement mécanique anisotrope, faiblement déformable (~ 1%). La maîtrise des relations entre la microstructure, l’endommagement et le comportement macroscopique est essentielle pour optimiser précisément le dimensionnement structurel de ce matériau pour les applications envisagées. Un paramètre de fabrication important est l'angle de tressage, angle entre les torons de fibres et l'axe du tube. L'objectif de ce travail est de fournir une compréhension détaillée de la relation endommagement-microstructure, en particulier des effets de l'angle de tressage sur les mécanismes d’endommagement. Dans ce but, une étude combinant observations expérimentales à macro et micro-échelle et simulations numériques est menée. Les tubes composites sont d’abord étudiés par des essais de traction in situ sous tomographie par rayons X. Les expériences ont été réalisées sur la ligne PSICHE du synchrotron SOLEIL sous faisceau rose polychromatique. Les images tridimensionnelles sont analysées par la technique de corrélation d’image volumique (DVC), complétée par une série d'algorithmes de traitement d'image originaux, développés spécifiquement pour analyser les microstructures 3D, mesurer les déformations à travers l'épaisseur du tube, détecter et caractériser quantitativement le réseau de microfissures créées par le chargement mécanique. De plus, les microstructures réelles, décrites par les images de haute résolution issues des tests in situ, sont utilisées dans les simulations numériques multi-échelle. Les champs de contrainte à l’échelle microstructurale sont calculés en régime élastique par une technique utilisant la transformée de Fourier rapide (FFT). Ils permettent de mieux comprendre l'initiation des fissures et d’interpréter les observations expérimentales par une comparaison directe. Ces approches expérimentales et numériques sont appliquées à trois tubes présentant différents angles de tressage (30 °, 45 ° et 60 °). L’influence de l'angle de tressage sur l'initiation et l'évolution de l’endommagement à cœur des composites est ainsi mise en évidenceBecause of their outstanding physical and chemical properties at high temperature, in comparison with metals, silicon carbide (SiC) composite materials are studied as possible nuclear fuel cladding materials either for future advanced fission/fusion reactors, or more recently, for the currently existing light water reactors. 2D-braided SiC/SiC composite tubes, manufactured by chemical vapor infiltration (CVI), exhibit an anisotropic, hardly deformable (~1%) mechanical behavior. Understanding the relations between the microstructure, the damage mechanisms and the macroscopic behavior is essential to optimize the structural design of this material for the considered applications. One important manufacturing parameter is the braiding angle, i.e. the angle between the fiber tows and the tube axis. The objective of this work is to provide a comprehensive understanding of the damage-microstructure relations, in particular of the effects of the braiding angle on the damage mechanisms. For this purpose, an investigation combining experimental observations at macro and micro-scale and numerical simulations is developed. The composite tubes are first studied through in situ tensile testing under X-ray computed tomography. Experiments were carried out on the PSICHE beamline at synchrotron SOLEIL using a pink polychromatic beam. The recorded 3D images are processed using the digital volume correlation (DVC) technique, extended by a series of advanced image processing algorithms specifically developed in order to analyze the 3D microstructures, to measure the deformations through the tube thickness, and to detect and quantitatively characterize the network of micro-cracks created by the mechanical loading. In addition, numerical simulations are performed on the real microstructures as observed in the high-resolution images recorded during the in situ tests. Stress fields are calculated at the microstructural scale in the elastic regime using a numerical tool based on the Fast Fourier Transform (FFT). They help to better understand crack initiation and interpret the experimental observations within one-to-one comparisons. Both the experimental and numerical approaches are applied to three tubes with different braiding angles (30°, 45° and 60°). The effect of the braiding angle on the initiation and evolution of damage in the bulk of the composite materials can thus be highlighted
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Lei, Song. "Informative correlation extraction from and for Forex market analysis." AUT University, 2010. http://hdl.handle.net/10292/899.
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The forex market is a complex, evolving, and a non-linear dynamical system, and its forecast is difficult due to high data intensity, noise/outliers, unstructured data and high degree of uncertainty. However, the exchange rate of a currency is often found surprisingly similar to the history or the variation of an alternative currency, which implies that correlation knowledge is valuable for forex market trend analysis. In this research, we propose a computational correlation analysis for the intelligent correlation extraction from all available economic data. The proposed correlation is a synthesis of channel and weighted Pearson's correlation, where the channel correlation traces the trend similarity of time series, and the weighted Pearson's correlation filters noise in correlation extraction. In the forex market analysis, we consider 3 particular aspects of correlation knowledge: (1) historical correlation, correlation to previous market data; (2) cross-currency correlation, correlation to relevant currencies, and (3) macro correlation, correlation to macroeconomic variables. While evaluating the validity of extracted correlation knowledge, we conduct a comparison of Support Vector Regression (SVR) against the correlation aided SVR (cSVR) for forex time series prediction, where correlation in addition to the observed forex time series data is used for the training of SVR. The experiments are carried out on 5 futures contracts (NZD/AUD, NZD/EUD, NZD/GBP, NZD/JPY and NZD/USD) within the period from January 2007 to December 2008. The comparison results show that the proposed correlation is computationally significant for forex market analysis in that the cSVR is performing consistently better than purely SVR on all 5 contracts exchange rate prediction, in terms of error functions MSE, RMSE, NMSE, MAE and MAPE. However, the cSVR prediction is found occasionally differing significantly from the actual price, which suggests that despite the significance of the proposed correlation, how to use correlation knowledge for market trend analysis remains a very challenging difficulty that prevents in practice further understanding of the forex market. In addition, the selection of macroeconomic factors and the determination of time period for analysis are two computationally essential points worth addressing further for future forex market correlation analysis.
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Yip, Lai Ping Rhoda. "Comparing the effectiveness of differenet [sic] task types (information gap tasks and decision making tasks) on the promtotion [sic] of second language acquisition." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/557.
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McDaniel, Caitlin Christine. "Madoff Madness: A Textual Analysis of the SEC's response to the Madoff Ponzi Scheme." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/89486.
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On December 11, 2008, the financial world was in a panic as the United States Securities and Exchange Commission (SEC) announced the arrest of Bernard L. Madoff of Bernard L. Madoff Investment Securities, LLC, for orchestrating a $65 billion Ponzi scheme. An investigation took place into Madoff's practices, and as a result, it was revealed the SEC failed to catch Madoff years earlier as a result of its business practices. After this became known, the SEC faced reputational harm. This qualitative analysis seeks to discover through identification and analysis of themes and sub-themes of response strategies, the extent to which the SEC applied Situational Crisis Communication Theory (SCCT) in its crisis response, in order to examine SCCT's merit as a theory in government crisis communication research. This study also offers additional response strategies imposed by the SEC to suggest further expansion of SCCT in a government context.Master of Arts
On December 11, 2008, Bernard L. Madoff, of Bernard L. Madoff Investment Securities, LLC, was charged by the United States Securities and Exchange Commission (SEC) for his role in a $65 billion fraudulent scheme. During an investigation into Madoff’s business practices, it was revealed that the SEC overlooked many red flags that could have caught Madoff years earlier. As a result, the SEC faced reputational harm. This study examined the SEC’s crisis response to the public following the news of Madoff’s arrest by applying a crisis communication theory to discover “best practices” for government agencies when dealing with a preventable crisis. This study also offers suggestions to further expand crisis communication research and crisis response strategies in a government communication setting.
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Carballo, Jose M. "Residual Stress Analysis in 3C-SiC Thin Films by Substrate Curvature Method." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1590.
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Development of thin films has allowed for important improvements in optical, electronic and electromechanical devices within micrometer length scales. In order to grow thin films, there exist a wide variety of deposition techniques, as each technique offers a unique set of advantages. The main challenge of thin film deposition is to reach smallest possible dimensions, while achieving mechanical stability during operating conditions (including extreme temperatures and external forces, complex film structures and device configurations). Silicon carbide (SiC) is attractive for its resistance to harsh environments, and the potential it offers to improve performance in several microelectronic, micro-electromechanical, and optoelectronic applications. The challenge is to overcome presence of high defect densities within structure of SiC while it is grown as a crystalline thin film. For this reason is important to monitor levels of residual stress, inherited from such grown defects, and which can risk the mechanical stability of SiC- made thin film devices.
Stoney's equation is the theoretical foundation of the curvature method for measuring thin film residual stress. It connects residual film stress with substrate curvature through thin plates bending mechanics. Important assumptions and vii simplifications are made about the film-substrate system material properties, dimensions and loading conditions; however, accuracy is reduced upon applying such simplifications. In recent studies of cubic SiC growth, certain Stoney's equation assumptions are violated in order to obtain approximate values of residual stress average. Furthermore, several studies have proposed to expand the scope of Stoney's equation utility; however, such expansions demand of more extensive substrate deflection measurements to be made, before and after film deposition.
The goal of this work is to improve the analysis of substrate deflection data, obtained by mechanical profilometry, which is a simple and inexpensive technique. Scatter in deflection data complicates the use of simple processes such as direct differentiation or polynomial fitting. One proposed method is total variation regularization of differentiation process; and results are promising for the adaptation of mechanical profilometry for complete measurement of all components of non-uniform substrate curvature.
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Brown, Dennis W. "SPC toolbox : a MATLAB based software package for signal analysis /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA305260.
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Thesis (M.S. in Electrical Engineering ) Naval Postgraduate School, September 1995."September 1995." Thesis advisor(s): Monique P. Fargues. Includes bibliographical references. Also available online.
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Zhang, Yixia, and 張義霞. "Refined non-conforming linear and nonlinear finte [sic] element analysis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242704.
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Lee, Yiu-cheung, and 李耀祥. "Quatitative [sic] analysis of residential property value in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B3126900X.
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Chan, Chunwa. "Design, simulation and analysis of RESURF Si/SiC power LDMOSFETs." Thesis, University of Warwick, 2018. http://wrap.warwick.ac.uk/102005/.
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It is necessary for power laterally diffused MOSFETs (LDMOSFETs) to operate efficiently and reliably in high temperature (< 300 °C), hostile environments such as those found in downhole, space, automotive and aerospace applications. Currently, silicon-oninsulator (SOI) technology is a dominant method to achieve this goal due to low leakage current and complete electrical isolation. However, the buried oxide (BOX) layer causes self-heating, which can impact device performance, cause thermal runaway and shorten device lifetime. To address this issue, one solution is to combine a silicon thin film with a semi-insulating (SI) SiC substrate, forming the Si/SiC architecture. LDMOSFETs built on this substrate are expected to deliver much better thermal performance, with electrical isolation comparable to the SOI case. However, the Si/SiC LDMOSFETs do not have a strong substrate assisted depletion effect, which can result in poorer electrical performance than those of the Reduced Surface Field (RESURF) bulk-Si and SOI LDMOSFETs. This thesis investigates the PN and SOI RESURF layouts and uses them to optimise 190 V and 600 V Si/SiC LDMOSFETs. DC and transient modelling will be conducted on the optimised Si/SiC and their SOI and bulk-Si equivalents. Based upon this, several comparative studies are conducted on their simulation results to see the effects of the Si/SiC architecture on the LDMOS designs. The comparative studies are made on the 600 V Si/SiC LDMOSFETs and their bulk Si and SOI equivalents. It is shown that the Si/SiC devices have the potential to operate with an off-state leakage current as low as the SOI device. However, the low-side resistance of the SOI LDMOSFET is smaller in value and less sensitive to temperature, outperforming both Si/SiC devices. Conversely, under high-side configurations, the Si/SiC transistors have resistances lower than that of the SOI at high substrate bias, and invariable with substrate potential up to −200 V, which behaves similar to the bulk-Si LDMOS at 300 K. A clamped-inductive switching circuit is simulated for the Philips SOI and the Si/SiC equivalent. It is shown that even though the SOI has a smaller chip area and suffered from strong substrate effects during the transient state, the two devices had similar currents and power dissipations at the gate, drain and source. The turn-on losses are higher than that of the turn-off losses due to the presence of parasitic capacitors. However, these similarities do not lead to similar thermal responses in both devices and the SOI is heated up at a much faster rate. By contrast, the SiC substrate in the Si/SiC behaves like an embedded heat sink regulating device temperature close to that of the ambient environment (423 K). In the high current condition, the peak temperature in the Si/SiC is 425 K, lower than 463 K in the SOI, thereby increasing reliability. The comparative studies are carried out on the 190 V LDMOSFETs in SOI, Si/SiC, Partial SOI (PSOI) and PSOSIC technology, based upon a capacitive and an inductive switching circuit. It is revealed that in spite of having a chip area 75% larger than the SOI structure, the Si/SiC solution undergoes negligible heating in any of the switching conditions simulated, exhibiting a very high energy capability. By contrast, the 22% area increase in the PSOSiC does not considerably change the way the energy is handled. This indicates that the Si/SiC is much more effective than PSOI and PSOSIC in dealing with the transient heating.
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Fiorello, Michael D. "An analysis of the major pre-Siniatic [sic] worship narratives." Columbia, SC : Columbia Biblical Seminary and Graduate School of Missions, 2000. http://dx.doi.org/10.2986/tren.023-0154.
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Zhang, Yixia. "Refined non-conforming linear and nonlinear finte [sic] element analysis." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22753060.
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Lee, Yiu-cheung. "Quatitative [sic] analysis of residential property value in Hong Kong /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19872537.
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Macklin, Kendrick R. "Benchmarking and analysis of the SRC-6E reconfigurable computing system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FMacklin.pdf.
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Lalime, Aimee L. "Development of a Computationally Efficient Binaural Simulation for the Analysis of Structural Acoustic Data." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34524.
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Binaural simulation is the recreation of a three-dimensional audio environment around a listener's head. The binaural simulation of structural acoustic data would open new opportunities in virtual prototyping and simulation. By modeling the structure as an array of vibrating monopoles and applying Head Related Transfer Functions (HRTFs) to each of the sources, a binaural simulation of this type can be created. Unfortunately, this simulation method requires an extensive amount of computer power and speed for real-time simulation, more so than is available with current technology.
The objective of this research is to reduce the number of computations required in the binaural simulation of structural acoustic data. This thesis details two methods of reducing the number of real-time calculations required in this binaural analysis: singular value decomposition (SVD), and equivalent source reduction (ESR). The SVD method reduces the complexity of the HRTF computations by breaking the HRTFs into dominant singular values and vectors. The ESR method reduces the number of sources to be analyzed in real-time by replacing sources on the scale of a structural wavelength with sources on the scale of an acoustic wavelength. The ESR and SVD reduction methods can be combined to provide an estimated computation time reduction of 99.4%. In addition, preliminary tests show that there is a 97% correlation between the results of the combined reduction methods and the results found with current binaural simulation techniques.Master of Science
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VanSant, April Nelson. "Studies on Hydrogen-Pinch Analysis and Application of COSMO-SAC to Electrolytes." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/34828.
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This thesis describes the results of two process system engineering studies: (1) hydrogen pinch analysis; and (2) application of COSMO-SAC (conductor-like screening model â segment activity coefficient) to electrolytes. Part (1) presents an automated spreadsheet method that can quickly help minimize fresh hydrogen consumption and maximize hydrogen recovery and reuse in petroleum refineries and petrochemical complexes. Part (1) has appeared as a featured article on engineering practice in the Chemical Engineering Magazine, volume 115, pp. 56-61, June 2008. We present an automated spreadsheet on our research group website (www.design.che.vt.edu) and describe procedures for using the spreadsheet in this thesis. Part (2) discusses the application of the conductor-like screening model â segment activity coefficient (COSMO-SAC), a liquid-phase activity-coefficient model, to electrolytes. We offer detailed procedure for obtaining sigma profiles for electrolytes. A sigma profile is a molecular-specific probability distribution of the surface-charge density, which enables the application of solvation-thermodynamic models to predict vapor-liquid and solid-liquid equilibria, and other properties. We propose to add an additional term to the exchange energy to account for ion-ion attractive and repulsive forces. We also look at the resulting exchange energy behavior. Although accurate numerical results are not achieved, we are able to produce results that match literature data by adding an adjustment factor.Master of Science
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Matras, Jan. "Aplikace reaktivních nanočástic do SAC pájecí pasty." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377074.
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This work is a research on the topic of reactive nanoparticles and their agitation into the solder paste, which it also describes. It describes in detail the properties of each solder alloys. It explains the creation of intermetallic layers in the soldering process and examines their structure. It also focuses on the evaluation and methodology of testing the properties of solder pastes. In the practical part, individual tests are performed with PF606 and PF610 solder paste.
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Zhang, Lianyang 1964. "Analyis [sic] and design of drilled shafts in rock." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9505.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.Includes bibliographical references (p. 713-732).
Drilled shafts are widely used to transfer heavy structural loads (both axial and lateral) through the overburden soil to the underlying rock mass. It is important to consider the effect of discontinuities when designing drilled shafts in rock. This thesis develops (1) a new design method for axially loaded rock-socketed shafts; (b) new design methods for laterally loaded rock-socketed shafts; and (c) a method for assessing the three dimensional (30) geometric characteristics of discontinuities. The new design method for axially loaded rock-socketed shafts concentrates on the prediction of the ultimate side shear resistance and the end bearing capacity. New relations have been developed for both the side shear resistance and the end bearing capacity. Both developments are derived from the analysis of ex.tensive databases. For laterally loaded rock-socketed shafts, a simplified design method and a detailed design method were developed. The simplified design method assumes that the rock mass is isotropic and uses an elasto-plastic continuum model to predict the load-displacement response. This model can consider drilled shafts in rock overlain by soil and it was validated by comparing its results with available theoretical solutions and field test data. The detailed design method considers the effect of anisotropy of jointed rock masses. The key components of this method are the 30 geometric characterization of discontinuities and the estimation of the anisotropic defonnation and strength properties of jointed rock masses. The 30 characterization of discontinuities uses the observed trace data in a finite circular window (on an exposed outcrop or at the bottom of a shaft hole) to determine the corrected trace length distribution, the discontinuity size (diameter) distribution, the total number of discontinuities in an objective volume, and finally the fracture tensor which describes the intensity and orientation of all discontinuities in a rock mass. The method for estimating the anisotropic elastic deformation properties uses the superposhion-principle and adopts an equivalent continuum approach. Hill's criterion is used to describe the anisotropic yield/failure of jointed rock masses. The method was then applied to examine the effect of anisotropy on the lateral deformation of rock-socketed shafts. Also, design charts were developed for considering the effect of anisotropy when predicting the elastic defonnation of laterally loaded rock-socketed shafts. Finally, the applicability of the recommended design methods is discussed and a design example is presented.
by Lianyang Zhang.
Ph.D.
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yin, jian. "High Temperature SiC Embedded Chip Module (ECM) with Double-sided Metallization Structure." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/30076.
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The work reported in this dissertation is intended to propose, analyze and demonstrate a technology for a high temperature integrated power electronics module, for high temperature (e.g those over 200oC) applications involving high density and low stress.
To achieve this goal, this study has examined some existing packaging approaches, such as wire-bond interconnects and solder die-attach, flip-chip and pressure contacts. Based on the survey, a high temperature, multilayer 3-D packaging technology in the form of an Embedded Chip Module (ECM) is proposed to realize a lower stress distribution in a mechanically balanced structure with double-sided metallization layers and material CTE match in the structure.
Thermal and thermo-mechanical analysis on an ECM is then used to demonstrate the benefits on the cooling system, and to study the material and structure for reducing the thermally induced mechanical stress. In the thermal analysis, the high temperature ECM shows the ability to handle a power density up to 284 W/in3 with a heat spreader only 2.1x2.1x0.2cm under forced convection. The study proves that the cooling system can be reduced by 76% by using a high temperature module in a room temperature environment.
Furthermore, six proposed structures are compared using thermo-mechanical analysis, in order to obtain an optimal structure with a uniform low stress distribution. Since pure Mo cannot be electroplated, the low CTE metal Cr is proposed as the stress buffering material to be used in the flat metallization layers for a fully symmetrical ECM structure. Therefore, a chip area stress as low as 126MPa is attained.
In the fabrication process, the high temperature material glass and a ceramic adhesive are applied as the insulating and sealing layers. Particularly, the Cr stress buffering layer is successfully electroplated in the high temperature ECM by means of the hard chrome plating process. The flat metallization layer is accomplished by using a combined structure with Cr and Cu metallization layers.
The experimental evaluations, including the electrical and thermal characteristics of the ECM, have been part of in the study. The forward and reverse characteristics of the ECM are presented up to 250oC, indicating proper device functionality. The study on the reverse characteristics of the ECM indicates that the large leakage current at high temperature is not due to the package surrounding the chip, but chiefly caused by the Schottky junction and the chip passivation layer. Finally, steady-state and transient measurements are conducted in terms of the thermal measurements. The steady-state thermal measurement is used to demonstrate the cooling system reduction. To obtain the thermal parameters of the different layers in the high temperature ECM, the transient thermal measurement is applied to a single chip ECM based on the temperature cooling-down curve measurement.Ph. D.
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Soueidan, Maher. "Croissance hétéroépitaxiale du SiC-3C sur substrats SiC hexagonaux; Analyses par faisceaux d'ions accélérés des impuretés incorporées." Phd thesis, Université Claude Bernard - Lyon I, 2006. http://tel.archives-ouvertes.fr/tel-00136231.
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L'utilisation de germes Si pour l'épitaxie du SiC-3C génère de nombreux défauts dans les couches enraison du désaccord de maille et de la dilatation thermique. Le SiC-3C peut aussi être déposé sur
substrats SiC-α(0001) en s'affranchissant des problèmes rencontré sur substrat Si. La difficulté de
contrôler la germination initiale génère cependant des macles qui sont difficiles à éviter ou éliminer
ensuite.
L'utilisation de l'épitaxie en phase vapeur comme technique de croissance n'a pas permis de
s'affranchir de ces macles malgré l'optimisation de la préparation de surface des germes SiC- α. En revanche, des couches de SiC-3C exemptes de macle ont été obtenues en utilisant une technique de
croissance originale, les mécanismes vapeur-liquid-solide, qui consiste à alimenter un bain Si-Ge avec
du propane.
La caractérisation des couches ainsi élaborées a montré une excellente qualité cristalline avec toutefois une incorporation non négligeable d'impuretés. Les éléments Al, Ge, B et Sn ont été dosés avec succès en utilisant des analyses par faisceaux d'ions accélérés, techniques peu conventionnelles pour SiC et présentant un challenge analytique.
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Soueidan, Maher. "Croissance hétéroépitaxiale du SiC-3C sur substats SiC hexagonaux : analyses par faisceaux d'ions accélérés des impuretés incorporées." Lyon 1, 2006. http://tel.archives-ouvertes.fr/docs/00/13/62/31/PDF/these_soueidan.pdf.
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L’utilisation de germes Si pour l’épitaxie du SiC-3C génère de nombreux défauts dans les couches en raison du désaccord de maille et de la dilatation thermique. Le SiC-3C peut aussi être déposé sur substrats SiC-α(0001) en s’affranchissant des problèmes rencontré sur substrat Si. La difficulté de contrôler la germination initiale génère cependant des macles qui sont difficiles à éviter ou éliminer ensuite. L'utilisation de l'épitaxie en phase vapeur comme technique de croissance n'a pas permis de s'affranchir de ces macles malgré l'optimisation de la préparation de surface des germes SiC- α. En revanche, des couches de SiC-3C exemptes de macle ont été obtenues en utilisant une technique de croissance originale, les mécanismes vapeur-liquid-solide, qui consiste à alimenter un bain Si-Ge avec du propane. La caractérisation des couches ainsi élaborées a montré une excellente qualité cristalline avec toutefois une incorporation non négligeable d'impuretés. Les éléments Al, Ge, B et Sn ont été dosés avec succès en utilisant des analyses par faisceaux d’ions accélérés, techniques peu conventionnelles pour SiC et présentant un challenge analytiqueUsing silicon as substrate for growing 3C-SiC monocrystalline material generates too many defects in the layers due to lattice and thermal expansion mismatch. Though these difficulties are avoided by using hexagonal SiC substrates, the random formation of 60° rotated domains in the 3C layers generate a high density of twins. The use of vapour phase epitaxy for the growth did not allow reducing significantly the twin density despite the optimization of the in situ surface preparation of the seeds. On the other hand, these defects were eliminated by using Vapor-Liquid-Solid mechanism which consists in feeding a Si-Ge melt with propane. The characterization of these twin-free layers showed excellent crystalline quality. Some of the impurities incorporated during growth (Ge, Al, B, Sn) were successfully analysed using accelerated ion beam techniques though the detection and quantification of these elements inside SiC thin films are challenging
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Das, Abhishek. "Analyses of crash occurence [sic] and inury [sic] severities on multi lane highways using machine learning algorithms." Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002928.
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Perry, Kourtnie. "An analysis of race and gender portrayls [sic] on television commercials." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1163799784.
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Thesis (M.A.)--University of Akron, School of Communication, 2006."December, 2006." Title from electronic thesis title page (viewed 10/15/2007) Advisor, Dudley B. Turner; Faculty readers, N. J. Brown, Kathleen D. Clark; Director, School of Communication, Carolyn Anderson ; Dean of the College, James Lynn; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Char, Srinidhi Narasimha. "Transmission gate based logic for differential power analysis resistant circcuits [sic]." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1193079255/.
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Patience, Trudy. "Sequence analysis of a Cowdria ruminantium lamdba (sic) GEM-11 clone." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53052.
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Thesis (MSc)--Stellenbosch University, 2002.ENGLISH ABSTRACT: Heartwater is a major threat to livestock in Africa due to its high mortality rate. The intracellular nature of the causative organism, Cowdria ruminantium, makes it difficult to study, hence an effective and user-friendly vaccine has been extremely difficult to obtain. Two C. ruminantium DNA libraries have recently been constructed, the lambda GEM11 bacteriophage DNA library and the lambda ZAPII bacteriophage DNA library, and this has lead to a renewed search for protective genes that could be used as a vaccine against heartwater. In this study, several molecular techniques including PCR, cloning and sequencing were used to identify genes in the lambda GEM11 bacteriophage DNA library that code for proteins, which could be used as vaccines to protect susceptible animals against heartwater. The lambda GEM11 library was screened with a rickettsial secretory protein gene sequence, known as seeD. One positive colony was selected from which the bacteriophage DNA was isolated. The C. ruminantium DNA was amplified from the bacteriophage DNA by using PCR and C. ruminantium-specific primers. The C. ruminantium DNA was screened with Mycoplasma, bovine and Cowdria DNA probes. The amplified DNA was subeloned into two vectors and the clones were screened by restriction analysis to identify clones containing inserts. The appropriate clones were sequenced and overlapping sequences matched, ordered and aligned. Two sequences were continuous with a short sequence of unidentified bases in between. Oligonucleotide primers were designed to amplify the DNA sequence between the two contiguous sequences. This led to the identification of the entire sequence of the C. ruminantium genome contained within the bacteriophage plaque. The single contiguous sequence was analysed and the putative protein-coding sequences were obtained and compared to DNA sequences of known organisms using the BLAST program. Five open reading frames were identified with homology to genes encoding specific proteins in bacteria. Two open reading frames showed homology to the genes encoding the transporter proteins, FtsY and the ABC transporter, and three open reading frames were found to be homologous to genes encoding the essential enzymes dethiobiotin synthetase, pro lipoprotein diacylglycerol transferase and the putative NADH-ubiquinone oxidoreductase subunit. The five open reading frames encode for genes, which are essential for the normal functioning of the C. ruminantium organism. However, these open reading frames might not be effective for use in a DNA vaccine since none of the open reading frames showed homology to obvious genes that could play a role in immunity and therefore confer protection. The open reading frames can be used in mutagenesis studies to produce attenuated strains of the organism that possess mutated versions of these proteins. These attentuated strains could be used for the vaccination of cattle, and thereby confer protection against viable pathogenic C. ruminantium isolates.
AFRIKAANSE OPSOMMING: Hartwater is 'n bedreiging vir vee in Afrika weens die hoë mortaliteitssyfer verbonde aan die siekte. Die intrasellulêre aard van die organisme wat hartwater veroorsaak, Cowdria ruminantium, bemoeilik navorsing aangaande die organisme. Dit het tot gevolg dat 'n effektiewe en gebruikersvriendelike entstof moeilik bekombaar is. Daar is onlangs sukses behaal met die konstruksie van twee C. ruminantium DNA genoteke, die lambda GEM11 bakteriofaag genoteek en die lambda ZAPII bakteriofaag genoteek. Dit het gelei tot 'n herlewing in die soektog na beskermende gene, wat in 'n entstof teen hartwater gebruik kan word. In hierdie studie is verskeie molekulêre tegnieke insluitende PKR, klonering en geenopeenvolging bepaling, gebruik om gene te identifiseer in die lambda GEM11 bakteriofaag genoteek wat kodeer vir proteïene wat in entstowwe gebruik kan word as beskerming teen hartwater. Die secD geen is gebruik om die lambda GEM11 bakteriofaag genoteek te sif. Een positiewe plaak is gevind waarna die DNA uit die bakteriofaag plaak geïsoleer en die C. ruminantium DNA vanuit die bakteriofaag plaak geamplifiseer is deur gebruik te maak van PKR en spesifieke C. ruminantium inleiers. Die C. ruminantium DNA is gesif met Mycoplasma, bees en Cowdria radioaktief gemerkte DNA peilers. Die C. ruminantium DNA is vervolgens in twee vektore gekloneer. Die klone is gesif deur middel van restriksie analise. Die DNA volgorde van die klone is bepaal en twee ononderbroke sekwense is geïdentifiseer met 'n gaping in die middel tussen die twee sekwense. Oligonukleotied inleiers is daarna ontwerp om die geenopeenvolging van die gaping tussen die twee sekwense te vul. Hierdeur kon die volledige geenopeenvolging van die genoom van C. ruminantium wat in die lambda GEM 11 bakteriofaag plaak voorkom, bepaal word. Hierdie volledige geenopeenvolging is vervolgens geanaliseer en die oop leesrame wat daarin voorkom geïdentifiseer. Vyf leesrame is gevind om homologie met gene wat kodeer vir proteïene wat in bakterieë voorkom, te toon. Twee leesrame het homologie met die gene wat kodeer vir transport proteïene, FtsYen die ABC transporter getoon, en drie leesrame het homologie met gene wat kodeer vir die essensiële ensieme detiobiotin sintetase, prolipoproteïen diasielgliserol transferase en die NADHubikinoon oksidoreduktase subeenheid getoon. Dié vyf leesrame het die potensiaal om as entstowwe gebruik te word aangesien al vyf leesrame kodeer vir gene wat 'n belangrike rol speel in die oorlewing van die C. ruminantium organisme. Alhoewel die leesrame moontlik nie so effektief sal wees in 'n DNA entstof nie, toon dit potensiaal om in mutasieeksperimente gebruik te word. Organismes wat die gemuteerde weergawe van die geen besit sal nie-funksionele proteïene produseer, wat 'n invloed kan hê op die normale fisiologiese funksies van die organisme en dus sal lei tot 'n minder virulente organisme. Die geattenueerde organisme kan moontlik gebruik word om diere te immuniseer en daardeur immuniteit aan diere lewer wat beskerming sal bied teen patogeniese C. ruminantium isolate.
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Waschura, Thomas E. "625 MBIT/SEC BIT ERROR LOCATION ANALYSIS FOR INSTRUMENTATION RECORDING APPLICATIONS." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609650.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaThis paper describes techniques for error location analysis used in the design and testing of high-speed instrumentation data recording and communications applications. It focuses on the differences between common bit error rate testing and new error location analysis. Examples of techniques presented include separating bit and burst error components, studying probability of burst occurrences, looking at error free interval occurrence rates as well as auto-correlating error position. Each technique contributes to a better understanding of the underlying error phenomenon and enables higher-quality digital recording and communication. Specific applications in error correction coding emulation, magnetic media error mapping and systematic error interference are discussed.