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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
871

Z-source, Full Bridge Dc/dc Converter

Pekuz, Cagdas 01 December 2010 (has links) (PDF)
The thesis is related to investigate characteristics and performance of a Z-source full bridge dc/dc converter which boosts the input voltage to a higher output voltage. Zsource structure increases the reliability of the converter according to current fed full bridge dc/dc converter and also reducing the complexity according to two stage design approach (boost followed by full bridge). Operating principles of the Z-source dc-dc converter is described by current and voltage waveforms of the components and mathematical expressions. Moreover, small signal models and transfer functions are derived for both continuous current mode (CCM) and discontinuous current mode (DCM) operations of the converter. Waveforms obtained, mathematical expressions, small signal models and transfer functions derived are confirmed by simulations. Performance of the converter and controller are both tested in laboratory prototype.
872

Production Of Z + Jet And Hf Jet Energy Scale Calibration At 7 Tev In The Cms Experiment At Lhc

Bilin, Bugra 01 September 2011 (has links) (PDF)
Forward Jet Calibration for CMS detector is presented using Z boson + jet event samples in the pseudorapidity region of 0 &lt / |&eta / | &lt / 5. The results are based on proton-proton collision data at center of mass energy of &radic / s = 7 TeV corresponding to &sim / 1 fb&minus / 1 of data. Z bosons are reconstructed from opposite sign lepton pairs (&mu / +&mu / &minus / , e+e&minus / ) and the transverse momentum balance of the Z boson and the associated jet is used to derive the calibration coefficients. The coefficients are tested on jets from a WW Monte Carlo sample using the W-mass constraint. The W mass peak position is observed to be improved by 20 % without loss of resolution.
873

Search For Z

Sahin, Mehmet Ozgur 01 April 2012 (has links) (PDF)
In this thesis, analysis of the forward backward asymmetry of high energy electron pairs at the CMS - LHC with a centre of mass energy of 7 TeV is presented and the possibility of search for a new neutral weak boson Z&rsquo / via measuring the forward backward asymmetry AFB of high energy electron pairs is discussed. The forward backward asymmetry is a natural result of the interference between the neutral current mediators: Photon and Z boson. A new neutral gauge boson would also interfere with these mediators and this new interference would either enhance the forward backward asymmetry at high energies or suppress it. In this analysis, 4.67 fb&minus / 1 data collected at the CMS experiment in 2011 is used
874

Distribution Network Modeling and Capacitor Placement Application

Su, Yuh-Sheng 14 August 2002 (has links)
Enhancing the quality of services in the distribution system is an important topic for power system research. It is imperative to employ precise network modeling and effective simulation tools, and a good system model is the key. This dissertation starts with modifying the building algorithms of Y-admittance and Z-impedance matrices. The Y-matrix will be built according to phase sequences. With the facts that the line self-impedance is significantly greater than the mutual-coupling terms and the existence of a high r/x ratio in distribution, two decoupled load flow methods (Phase-Decoupled¡BPD and Sub-Phase-Decoupled¡BSPD) with Current Injection Model(CIM) were developed. A new Z-matrix building algorithm was also developed in this dissertation. It decomposed the traditional Z into two sub-matrices, the upper and lower triangular matrices respectively. The matrices represent the relationships between the branch current and the bus injection current, and between the bus voltage and the branch current. Enhancing the quality of services will be effectively achieved by a proper capacitor placement technique. This dissertation develops a linear relationships of voltage changes versus the capacitor compensation, the branch current changes versus the capacitor compensation, and loss reductions versus the capacitor compensation. For loss reduction, a linear optimization function was defined to solve the capacitor placement problem. Tests have shown that the proposed methods were suitable for applications to an unbalance distribution system.
875

Estetisk och teknisk karaktärsdesign : Hur en kvinnlig antagonist skapas med konventioner utifrån etablerade spel .

Hajjar, Elie January 2009 (has links)
<p>Examensarbetets stora fokus baseras på hur en kvinnlig antagonist skapas både utifrånestetiska och praktiska premisser. För den estetiska och tekniska normen utgick jag ifrånspelet Devil May Cry 4 (Capcom, 2008). Utifrån spelets modeller kunde en studie genomföraspå enstaka karaktärer där de tekniska begränsningar och den estetiska utformningen kundefastställas. Först har jag skapat ett koncept som baseras på de estetiska valen, och utifrånstudien fick jag fram informationen där jag kunde med hjälp av 3d program som användsinom spelbranschen tag fram en egen karaktär, i det här fallet en kvinnlig antagonist.Jag har velat skapa en kvinnlig spelkaraktär utifrån konventioner som samtidigt utmanas. Denkvinnliga antagonisten baseras på estetiska val och teman som framhäver karaktärenspersonlighet. Mina problemställningar är Hur kan koder och konventioner användas för attskapa en stark och framträdande kvinnlig karaktär? Och Hur kan de estetiska tillvalenappliceras med dagens tekniska metoder?</p>
876

A comparison of meta-analytic approaches to the analysis of reliability estimates [electronic resource] / by Denise Corinne Mason.

Mason, Denise Corinne. January 2003 (has links)
Includes vita. / Title from PDF of title page. / Document formatted into pages; contains 114 pages. / Thesis (Ph.D.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: In the last few years, several studies have attempted to meta-analyze reliability estimates. The initial study, to outline a methodology for meta-analyzing reliability coefficients, was published by Vacha-Haase in 1998. Vacha-Haase used a very basic meta-analytic model to find a mean effect size (reliability) across studies. There are two main reasons for meta-analyzing reliability coefficients. First, recent research has shown that many studies fail to report the appropriate reliability for the measure and population of the actual study (Vacha-Haase, Ness, Nilsson and Reetz, 1999; Whittington, 1998; Yin and Fan, 2000). Second, very little research has been published describing the way reliabilities for the same measure vary according to moderators such as time, form length, population differences in trait variability and others. / ABSTRACT: Vacha-Haase (1998) proposed meta-analysis, as a method by which the impact of moderators may become better understood. Although other researchers have followed the Vacha-Haase example and meta-analyzed the reliabilities for several measures, little has been written about the best methodology to use for such analysis. Reliabilities are much larger on average than are validities, and thus tend to show greater skew in their sampling distributions. This study took a closer look at the methodology with which reliability can be meta-analyzed. Specifically, a Monte Carlo study was run so that population characteristics were known. This provided a unique ability to test how well each of three methods estimates the true population characteristics. / ABSTRACT: The three methods studied were the Vacha-Haase method as outlined in her 1998 article, the well-known Hunter and Schmidt "bare bones method" (1990) and the random-effects version of Hedges' method as described by Lipsey and Wilson (2001). The methods differ both in how they estimate the random-effects variance component (or in one case, whether the random-effects variance component is estimated at all) and in how they treat moderator variables. Results showed which of these methods is best applied to reliability meta-analysis. A combination of the Hunter and Schmidt (1999) method and weighted least squares regression is proposed. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
877

A rhetorical analysis of the preaching style of three African-American preachers with application for black homiletics

Asberry, Robert Lee. January 2000 (has links)
Thesis (D. Min.)--Dallas Theological Seminary, 2000. / Includes abstract. Includes bibliographical references (leaves 250-263).
878

Yield Spreads and Covenants : is there a negative relationship?

Ågren, Gustaf, Roth, Isak January 2015 (has links)
Research concerning covenants has at large not examined what quantifiable relationship covenants have with yield spreads. We shed light on this topic as we evaluate Swedish bond indentures. By examining the relationship between covenants and yield spread, our results indicate whether covenants effectively mitigate the bondholder-stockholder conflict. The results from our OLS-model indicate that the poison put option and covenants restricting dividends and mergers have a positive relationship with the yield spread, and that the negative pledge has a negative relationship with the yield spread. Furthermore, our results indicate that some covenants are too costly for companies issuing investment grade bonds. Those covenants are therefore only included in bonds with higher yield spreads, where a conflict between bondholders and stockholders could be greater. / Ett kvantifierbart förhållande mellan kovenanter och räntebasmarginalen har överlag i tidigare forskning inte undersökts. I denna uppsats åskådliggör vi detta förhållande genom att undersöka svenska företagsobligationer. Genom att studera relationen mellan kovenanter och räntebasmarginalen kan våra resultat visa på huruvida kovenanter motverkar konflikten mellan obligationsinnehavare och aktieägare. Resultaten från vår OLS-modell visar att poison put option och kovenanter som begränsar utdelningar och fusioner har ett positivt samband med räntebasmarginalen, medan negative pledge har ett negativt samband med räntebasmarginalen. Vidare visar våra resultat att vissa kovenanter är för dyra för företag som ger ut investment grade obligationer. Dessa kovenanter finns därför bara med i obligationer med högre räntebasmarginaler, där en konflikt mellan obligationsinnehavare och aktieägare kan vara större.
879

Mathematical Modelling of The Global Positioning System Tracking Signals

Mama, Mounchili January 2008 (has links)
Recently, there has been increasing interest within the potential user community of Global Positioning System (GPS) for high precision navigation problems such as aircraft non precision approach, river and harbor navigation, real-time or kinematic surveying. In view of more and more GPS applications, the reliability of GPS is at this issue. The Global Positioning System (GPS) is a space-based radio navigation system that provides consistent positioning, navigation, and timing services to civilian users on a continuous worldwide basis. The GPS system receiver provides exact location and time information for an unlimited number of users in all weather, day and night, anywhere in the world. The work in this thesis will mainly focuss on how to model a Mathematical expression for tracking GPS Signal using Phase Locked Loop filter receiver. Mathematical formulation of the filter are of two types: the first order and the second order loops are tested successively in order to find out a compromised on which one best provide a zero steady state error that will likely minimize noise bandwidth to tracks frequency modulated signal and returns the phase comparator characteristic to the null point. Then the Z-transform is used to build a phase-locked loop in software for digitized data. Finally, a Numerical Methods approach is developed using either MATLAB or Mathematica containing the package for Gaussian elimination to provide the exact location or the tracking of a GPS in the space for a given a coarse/acquisition (C/A) code.
880

Leveraging genomic approaches to characterize mitochondrial RNA biology

Wolf, Ashley Robin 04 June 2015 (has links)
Transcription and translation of mammalian mitochondrial DNA (mtDNA) occurs within the mitochondrial matrix to produce oxidative phosphorylation subunits required for efficient energy production. These mtDNA-encoded subunits complex with mitochondrial-localized, nuclear-encoded subunits to form the respiratory chain, and aberrant production or function of these subunits can cause devastating human disease. In addition to 13 oxidative phosphorylation subunits, mtDNA encodes 2 rRNAs and 22 tRNAs. All proteins required for mitochondrial RNA transcription, processing, and translation are encoded in the nucleus and translocated into the mitochondria. Here, I characterize over 100 nuclear-encoded mitochondrial proteins with predicted RNA-binding domains. Using RNAi and an RNA profiling approach, MitoString, we further characterize previously identified RNA processing factors and identify the novel regulator FASTKD4, which influences the abundance of a subset of mitochondrial mRNAs. Next, we apply knowledge of the RNA degradation component SUPV3L1 gleaned from our RNAi studies and previous research to test whether a specific set of variants influence the function of this gene in patient fibroblasts. Using MitoString, we find no evidence of pathogenicity of these variants in our fibroblast model. Our approach highlights the value of a thorough understanding of mitochondrial proteins and the necessity of experimental techniques to validate the effect of variants found in exome-sequencing studies. Finally, we take an unbiased approach to characterizing the mitochondrial transcriptome of mouse liver by sequencing RNA from sequentially enriched mitochondrial fractions. Although we find an abundance of nuclear-encoded 5S rRNA, consistent with previous research, we fail to identify any imported nuclear-encoded tRNAs. Uniting genomics, biochemistry, and medicine, these findings advance our understanding of mitochondrial RNA biology.

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