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Wills, Rebecca Smith. "When Rank Trumps Precision: Using the Power Method to Compute Google?s PageRank." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-06122007-173712/.
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The PageRank algorithm, developed by Google founders Larry Page and Sergey Brin, assigns ranking scores to webpages that reflect their relative importance. These scores are based primarily on the link structure of the Web graph and correspond to elements of a dominant left eigenvector, called the PageRank vector, of the stochastic Google matrix. When the starting vector is a probability vector, the iterates of the power method applied to the Google matrix converge to the PageRank vector. Determining when to stop the iterations requires deciding when an iterate vector is good enough. Existing termination criteria rely on various measures of distance between successive iterate vectors. In this dissertation, we investigate how well a power method iterate vector approximates the PageRank vector, we show that the existing termination criteria do not guarantee accurate ranking, and we provide a computationally efficient criterion for determining relative rankings, exact rankings, and ranking intervals of PageRank scores.
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Cavender, Terri A. "The Use of the Power Method to Find Dominant Eigenvalues of Matrices." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc501200/.
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This paper is the result of a study of the power method to find dominant eigenvalues of square matrices. It introduces ideas basic to the study and shows the development of the power method for the most well-behaved matrices possible, and it explores exactly which other types of matrices yield to the power method. The paper also discusses a type of matrix typically considered impossible for the power method, along with a modification of the power method which works for this type of matrix. It gives an overview of common extensions of the power method. The appendices contain BASIC versions of the power method and its modification.
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Garcia-Valle, Rodrigo Joel. "Dynamic modelling and simulation of electric power systems using the Newton-Raphson method." Thesis, University of Glasgow, 2007. http://theses.gla.ac.uk/435/.
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The research work presented in this thesis is concerned with the development of a dynamic power flow computer algorithm using Newton's method. It addresses both the development of a positive sequence dynamic power flow algorithm for the dynamic study of balanced power systems and a fully-fledged three-phase dynamic power flow algorithm for the dynamic study of power systems exhibiting a significant degree of either structural or operational unbalance. As a prelude to the research work on dynamic power flows, a three-phase Newton-Raphson power flow algorithm in rectangular co-ordinates with conventional HVDC power plant modelling is presented in this thesis, emphasising the representation of converter control modes. The solution approach takes advantage of the strong numerical solutions for combined HVAC-HVDC systems, where power plant and operational imbalances are explicitly taken into account. The dynamic algorithm is particularly suited to carrying out long-term dynamic simulations and voltage stability assessments. Dynamic model representations of the power plants components and the load tap changing transformer are considered, and to widen the study range of dynamic voltage phenomena using this method, extensions have been made to include induction motor and polynomial load modelling features. Besides, reactive power compensators that base their modus operandi on the switching of power electronic valves, such as HVDC-VSC and the STATCOM are taken into account. The dynamic power flow algorithm has primarily been developed making use of the positive sequence and [dq] representations. Extensions are made to developing a three-phase power flows dynamic algorithm. Test cases for the various dynamic elements developed in this research are presented to show the versatility of the models and simulation tool, including a trip cascading event leading up to a wide-area voltage collaps. Comparisons with the output of a conventional transient stability program carried out where appropriate.
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Almgrund, Jonas. "Alternative Methods for Operational Optimization of Hydro Power Plants." Thesis, KTH, Optimeringslära och systemteori, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-252552.
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The aim of this thesis is to optimize hydro power plants with data generated from observations and field tests at the plants. The output is optimal production tables and curves in order to operate and plan hydro power plants in an optimized way concerning power output, efficiency and distribution of water. The thesis is performed in collaboration with Vattenfall AB, which currently use an internal optimization program called SEVAP. Two alternative methods have been selected, employed and compared with the current optimization program, these are Interior-Point Method and Sequential Quadratic Programming. Three start-point strategies are created to increase the probability of finding a global optima. A heuristic rule is used for selection of strategy in order to prevent rapid changes in load distribution for small variations in dispatched water. The optimization is performed at three plants in Sweden with different size and setup. The results of this evaluation showed marginally better results for the employed methods in comparison to the currently used optimization. Further, the developed program is more flexible and compatible to integrate with future digitalization projects.Syftet med detta examensarbete är att optimera vattenkraftverk med data som genererats från indextester vid kraftverken. Resultatet är optimala produktionstabeller och kurvor för drift och planering av vattenkraftverk. Dessa är baserade på att optimalt fördela vattnet mellan aggregaten för att maximera uteffekt och verkningsgrad. Detta arbete har utförts i samarbete med Vattenfall AB, som för närvarande använder ett internt optimeringsprogram som heter SEVAP. Två optimeringsmetoder har valts, implementerats och jämförts med det nuvarande optimeringsprogrammet. Dessa metoder är inrepunktsmetoden (IPM) och sekventiell kvadratiskt programmering (SQP). Tre startpunktsstrategier har används för att öka sannolikheten att hitta ett globalt optima. För att förhindra hastiga förändringar i lastfördelning för små variationer av avsänt vatten har en heuristisk regel används. Optimeringen har utförts på tre stationer med olika uppsättning och storlek. Resultatet av detta examensarbete visar marginellt bättre resultat för de använda metoderna i jämförelse med den nuvarande optimeringen. Det utvecklade programmet är flexibelt och kompatibelt att integrera med framtida digitaliseringsprojekt.
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Hussein, Anwar. "Fast methods for computing bifurcation points in power systems." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272745.
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Schollin, Malin. "I. A method of detecting episodes of hypoglycemia when missing data occur : II. A simulation study for the comparison of the power of three multivariate procedures." Thesis, Uppsala University, Department of Mathematics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121403.
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Sosa, Paz Carlos. "Numerical optimisation methods for power consumption in multi-hop mobile phone networks." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/752/.
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In recent years the importance of multi hop wireless networks has been growing mainly due to key factors such as: no backbone infrastructure or cost of installation are required and the network can be rapidly deployed and configured. A main problem in this kind of networks is to establish an efficient use of the power involved in the communication between network devices. In this dissertation, we present two different mathematical models which represent a multi hop wireless network: The first model considers the joint routing, scheduling and power control for TDMA/CDMA multi hop wireless network systems; minimising the used power to send messages through a multi hop wireless network. In this model we consider the scheduling of the message transmission. The scheduling is essential since it coordinates the transmission between devices in order to reduce the interference caused by the neighborhood devices and the background noise. Interference plays an important role in this kind of networks since the quality of service depends on it. We use two quality indicators: The Signal to Noise Ratio (SNR) and the Signal to Interference Noise Ratio (SINR). The second model considers the joint routing, power control for CDMA multi hop wireless network systems model in which we include two different filters: the Single User Matched Filter (SUMF) and the Minimum Mean Squared Error (MMSE), without considering the scheduling problem. The nature of the set of constraints inherent to both mathematical models is nonconvex, therefore we have a non convex optimisation problem. Since the problem is non convex, the obtained solutions are only local minimisers. We present and prove two theorems which, in general terms, state that at a local minimiser, the capacity over the links is fully exploited. We present different sets of experiments and numerical solution for both mathematical models.
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Caplen, Mark J. S. "The development and testing of a new integration method for the solution of stiff differential equations arising in the digital simulation of fluid power systems." Thesis, University of Bath, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383310.
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Massa, Julio Cesar. "Acceleration of convergence in solving the eigenvalue problem by matrix iteration using the power method." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101452.
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A modification of the matrix iteration using the power method, in conjunction with Hotelling deflation, for the solution of the problem K.x = ω².M.x is here proposed. The problem can be written in the form D.x =λ.x, and the modification consists of raising the matrix D to an appropriate power p before carrying out the iteration process.
The selection of a satisfactory value of p is investigated, based on the spacing between the eigenvalues. The effect of p on the accuracy of the results is also discussed.M.S.
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Garner, William Howard. "Iteration of the power operation." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941367.
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This thesis is an investigation of the sequence of functions defined by fl (x) -xand fn+1 (x) -x , where the power is the principal value.In the case where the sequence is restricted to positive real this sequence of functions over thecomplex plane, we attack real numbers, the problem yields to the methods of analysis and we prove the behavior of the sequence.The more general problem of describing the behavior of both analytically and numerically. Though no full rigorous solution is given, the results presented suggest the behavior of the sequence over the complex plane is very interesting.Department of Mathematical Sciences
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Uong, Hoang. "The application of the ordered list method and the dynamic programming to the unit commitment." PDXScholar, 1989. https://pdxscholar.library.pdx.edu/open_access_etds/3948.
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Noudjiep, Djiepkop Giresse Franck. "Feeder reconfiguration scheme with integration of renewable energy sources using a Particle Swarm Optimisation method." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2712.
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Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2018.A smart grid is an intelligent power delivery system integrating traditional and advanced control, monitoring, and protection systems for enhanced reliability, improved efficiency, and quality of supply. To achieve a smart grid, technical challenges such as voltage instability; power loss; and unscheduled power interruptions should be mitigated. Therefore, future smart grids will require intelligent solutions at transmission and distribution levels, and optimal placement & sizing of grid components for optimal steady state and dynamic operation of the power systems. At distribution levels, feeder reconfiguration and Distributed Generation (DG) can be used to improve the distribution network performance. Feeder reconfiguration consists of readjusting the topology of the primary distribution network by remote control of the tie and sectionalizing switches under normal and abnormal conditions. Its main applications include service restoration after a power outage, load balancing by relieving overloads from some feeders to adjacent feeders, and power loss minimisation for better efficiency. On the other hand, the DG placement problem entails finding the optimal location and size of the DG for integration in a distribution network to boost the network performance. This research aims to develop Particle Swarm Optimization (PSO) algorithms to solve the distribution network feeder reconfiguration and DG placement & sizing problems. Initially, the feeder reconfiguration problem is treated as a single-objective optimisation problem (real power loss minimisation) and then converted into a multi-objective optimisation problem (real power loss minimisation and load balancing). Similarly, the DG placement problem is treated as a single-objective problem (real power loss minimisation) and then converted into a multi-objective optimisation problem (real power loss minimisation, voltage deviation minimisation, Voltage stability Index maximisation). The developed PSO algorithms are implemented and tested for the 16-bus, the 33-bus, and the 69-bus IEEE distribution systems. Additionally, a parallel computing method is developed to study the operation of a distribution network with a feeder reconfiguration scheme under dynamic loading conditions.
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Mazumdar, Joy. "System and method for determining harmonic contributions from nonlinear loads in power systems." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/23215.
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The objective of this research is to introduce a neural network based solution for the problem of measuring the actual amount of harmonic current injected into a power network by an individual nonlinear load. Harmonic currents from nonlinear loads propagate through the system and cause harmonic pollution. As a result, voltage at the point of common coupling (PCC) is rarely sinusoidal. The IEEE 519 harmonic standard provides customer and utility harmonic limits and many utilities are now requiring their customers to comply with IEEE 519. Measurements of the customer’s current at the PCC are expected to determine the customer’s compliance with IEEE 519. However, results in this research show that the current measurements at the PCC are not always reliable in that determination. In such a case, it may be necessary to determine what the customer’s true current harmonic distortions would be if the PCC voltage could be a pure sinusoidal voltage. However, establishing a pure sinusoidal voltage at the PCC may not be feasible since that would mean performing utility switching to reduce the system impedance. An alternative approach is to use a neural network that is able to learn the customer’s load admittance. Then, it is possible to predict the customer’s true current harmonic distortions based on mathematically applying a pure sinusoidal voltage to the learned load admittance. The proposed method is called load modeling. Load modeling predicts the true harmonic current that can be attributed to a customer regardless of whether a resonant condition exists on the utility power system. If a corrective action is taken by the customer, another important parameter of interest is the change in the voltage distortion level at the PCC due to the corrective action of the customer. This issue is also addressed by using the dual of the load modeling method. Topologies of the neural networks used in this research include multilayer perceptron neural networks and recurrent neural networks. The theory and implementation of a new neural network topology known as an Echo State Networks is also introduced. The proposed methods are verified on a number of different power electronic test circuits as well as field data. The main advantages of the proposed methods are that only waveforms of voltages and currents are required for their operation and they are applicable to both single and three phase systems. The proposed methods can be integrated into any existing power quality instrument or can be fabricated into a commercial standalone instrument that could be installed in substations of large customer loads, or used as a hand-held clip on instrument.
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Li, Xiang. "Mathematical Model for Current Transformer Based On Jiles-Atherton Theory and Saturation Detection Method." UKnowledge, 2016. http://uknowledge.uky.edu/ece_etds/89.
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Current transformer saturation will cause the secondary current distortion. When saturation occurs, the secondary current will not be linearly proportional to the primary current, which may lead to maloperation of protection devices. This thesis researches and tests two detecting methods: Fast Fourier Transform (FFT) and Wavelet Transform based methods. Comparing these two methods, FFT has a better performance in steady state saturation, and Wavelet Transform can determine singularity to provide the moment of distortion.
The Jiles-Atherton (J-A) theory of ferromagnetic hysteresis is one approach used in electromagnetics transient modeling. With decades of development, the J-A model has evolved into different versions. The author summarizes the different models and implements J-A model in both MATLAB and Simulink.
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張啓軍 and Qijun Zhang. "The Galerkin Element Method and power flow in acoustic-structural problems with damped sandwich plates." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31239742.
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Power, Christian Andreas [Verfasser], and Christian [Akademischer Betreuer] Lubich. "Numerical Analysis of the evolving surface finite element method for some parabolic problems / Christian Andreas Power ; Betreuer: Christian Lubich." Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/1167248279/34.
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An, Qian. "A Monte Carlo study of several alpha-adjustment procedures using a testing multiple hypotheses in factorial anova." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1269439475.
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Adams, William Mark 1961. "APPLICATION OF THE VARIANCE-TO-MEAN RATIO METHOD FOR DETERMINING NEUTRON MULTIPLICATION PARAMETERS OF CRITICAL AND SUBCRITICAL REACTORS (REACTOR NOISE, FEYNMAN-ALPHA)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275438.
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Andersson, Johan. "Summation formulae and zeta functions." Doctoral thesis, Stockholm : Department of Mathematics, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1074.
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Vasireddy, Jhansi Lakshmi. "Applications of Linear Algebra to Information Retrieval." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/math_theses/71.
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Some of the theory of nonnegative matrices is first presented. The Perron-Frobenius theorem is highlighted. Some of the important linear algebraic methods of information retrieval are surveyed. Latent Semantic Indexing (LSI), which uses the singular value de-composition is discussed. The Hyper-Text Induced Topic Search (HITS) algorithm is next considered; here the power method for finding dominant eigenvectors is employed. Through the use of a theorem by Sinkohrn and Knopp, a modified HITS method is developed. Lastly, the PageRank algorithm is discussed. Numerical examples and MATLAB programs are also provided.
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Sulemana, Hisham. "Comparison of mortality rate forecasting using the Second Order Lee–Carter method with different mortality models." Thesis, Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-43563.
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Mortality information is very important for national planning and health of a country. Mortality rate forecasting is a basic contribution for the projection of financial improvement of pension plans, well-being and social strategy planning. In the first part of the thesis, we fit the selected mortality rate models, namely the Power-exponential function based model, the ModifiedPerks model and the Heligman and Pollard (HP4) model to the data obtained from the HumanMortality Database [22] for the male population ages 1–70 of the USA, Japan and Australia. We observe that the Heligman and Pollard (HP4) model performs well and better fit the data as compared to the Power-exponential function based model and the Modified Perks model. The second part is to systematically compare the quality of the mortality rate forecasting using the second order Lee–Carter method with the selected mortality rate models. The results indicate that Power-exponential function based model and the Heligman and Pollard (HP4) model gives a more reliable forecast depending on individual countries.
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Altoumaimi, Rasha Talal. "Nonlinear Least-Square Curve Fitting of Power-Exponential Functions: Description and comparison of different fitting methods." Thesis, Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-38606.
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This thesis examines how to find the best fit to a series of data points when curve fitting using power-exponential models. We describe the different numerical methods such as the Gauss-Newton and Levenberg-Marquardt methods to compare them for solving non-linear least squares of curve fitting using different power-exponential functions. In addition, we show the results of numerical experiments that illustrate the effectiveness of this approach.Furthermore, we show its application to the practical problems by using different sets of data such as death rates and rocket-triggered lightning return strokes based on the transmission line model.
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Cavedon, Carolina Christmann. "The Power of Reflective Professional Development in Changing Elementary School Teachers' Instructional Practices." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2075.
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With the new goal of K-12 education being to prepare students to be college and career ready at the end of high school, education needs to start changing at the elementary school level. The literature suggests that teachers need reflective professional development (PD) to effectively teach to the new standards and to demonstrate change to their current instructional practices. This mixed-method multiple-case study investigated the impacts of a reflective professional development (PD) in changing elementary school teachers' instructional practices.
Teachers Instructional Portfolios (TIPs) were scored with a TIP rubric based on best practices in teaching mathematics problem-solving and science inquiry. The TIPs were also analyzed with a qualitative coding scheme. Case descriptions were written and all the collected data were used to explain the impacts of the reflective PD on changes in teachers' instructional practices.
While we found no predictive patterns in relation to teachers changing their classroom practices based on the reflective PD, we claim that teachers' desire to change might contribute to improvements in instruction. We also observed that teachers' self-assessment scores tend to be higher than the actual TIP scores corroborating with the literature on the usage of self-assessment to evaluate teachers' instructional practices.
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Meireles, Eduardo David. "Uma contribuição ao estudo do problema de mal condicionamento de redes eletricas de potencia sob o ponto de vista de estabilidade de tensão." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261719.
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Orientadores: Carlos Alberto de Castro Junior, Luiz Carlos Pereira da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-04T14:18:50Z (GMT). No. of bitstreams: 1 Meireles_EduardoDavid_M.pdf: 1486956 bytes, checksum: 1e441015d6ae62bfd66ac90c0c7635dd (MD5) Previous issue date: 2005
Resumo: A literatura técnica registra uma série de metodologias propostas para a obtenção do estado de operação das chamadas redes mal condicionadas, ou seja, redes cujos modelos resultam em sistemas de equações de difícil resolução [1, 2]. Estas metodologias mostraram-se úteis também em situações em que a operação da rede é infactível, ou seja, situações em que o sistema de equações que representa a rede não apresenta soluções. Nestes casos, os métodos de resolução do problema de fluxo de carga convencionais divergem, não oferecendo informações úteis sobre a rede. Já as metodologias específicas para redes mal condicionadas oferecem, mesmo na situação de divergência, informações que podem ser úteis no sentido de apontar suas possíveis causas. Recentemente, foi levantada a possibilidade de que estas supostas redes mal condicionadas não existissem de fato, mas estivessem simplesmente operando em torno do seu limite de estabilidade de tensão [3], ou seja, o mal condicionamento seria resultado de problemas de estabilidade de tensão e não do mal condicionamento propriamente dito. De acordo com [3], após uma série de simulações não foram encontradas situações em que a rede fosse mal condicionada e estivesse operando em condições normais de operação no que diz respeito à estabilidade de tensão. Os testes mostrados em [3] foram realizados utilizando-se o fluxo de carga da continuação [4]. O objetivo deste trabalho é realizar alguns testes para analisar e discutir as conclusões de [3]. Para isso, algumas simulações adicionais foram realizadas para redes teste mal condicionadas apresentadas em [2], dentre outras. As conclusões deste trabalho apontam para a importância de se continuar a pesquisa para o desenvolvimento de métodos para a resolução de sistemas mal condicionados
Abstract: A number of methods for computing the operating state of the so-called ill-conditioned systems can be found in the literature. A power system is called ill-conditioned if its model results in a set of equations for which the resolution presents numerical difficulties [1, 2]. Those methods also showed to be useful tools in situations where the operation is unfeasible, that is, situations in which the set of equations that represents the network do not present any solution. In these cases the conventional load flow methods diverge and do not provide any useful information about the system operating condition. On the other hand, specific load flow methods for ill-conditioned systems do provide such information, even in divergence situations, and the possible causes of the numerical problems may be inferred. Recently, the possibility that the alleged ill-conditioned systems are in fact systems operating close to or beyond their voltage stability limit was discussed [3]. Therefore, the ill-conditioning would be the result of voltage stability problems rather than ill-conditioning itself. According to [3], after a number of simulations no situations where found such that the system was indeed ill-conditioned and was operating in normal condition as far as voltage stability is concerned. The tests carried out in [3] used continuation load method [4]. The main goal of this work is to carry out some simulation tests to analyze and discuss the conclusion presented in [3]. Also, some additional simulations were done for other ill-conditioned systems shown in [2], among others. The conclusions of this work point towards the importance of a continuing effort in the development of efficient methods for solving ill-conditioned systems
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Wu, Yu-Chi. "Direct nonlinear interior point methods for optimal power flows." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15030.
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Fadda, Mario. "Aspects of power domains and power locales." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24001.
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Several equivalent approaches to power domains are presented: the naturality of this concept for denotational semantics is stressed and its modal interpretation is explained. We show how to solve equations involving power domains and apply the theory to an equation that leads to a characterization of bisimulations. Power locales are introduced, as the analogue of both power domains and power spaces. We study the monads defined by the power locales, their algebras and the points of the power locales.
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Lazzaretti, André Eugenio. "Segmentação, classificação e detecção de novas classes de eventos em oscilografias de redes de distribuição de energia elétrica." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1144.
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CAPESEste trabalho apresenta novas abordagens para duas das etapas fundamentais relacionadas com análise automática de oscilografias de redes de distribuição: a detecção dos instantes transitórios e a sua classificação. Para comparação e validação dos métodos são utilizadas duas bases de dados, sendo uma delas formada por dados simulados no aplicativo Alternative Transient Program e outra contendo dados reais de oscilógrafos instalados em uma rede de distribuição de energia elétrica. Os dados reais apresentam um conjunto de eventos relevante para as análises aqui propostas, principalmente por conter uma gama variada de eventos, incluindo transitórios decorrentes de descargas atmosféricas. Com relação à detecção de transitórios (segmentação de oscilografias), foram testados os métodos atualmente propostos na literatura, os quais contemplam Filtro de Kalman, Transformada Wavelet Discreta e Modelos Autorregressivos, além de serem propostas duas novas técnicas baseadas no Operador de Energia de Teager e Representação de Dados Utilizando Vetores Suporte. Demonstra-se que, tanto para dados simulados quanto para dados reais, o método de detecção baseado na Representação de Dados utilizando Vetores Suporte aponta para um melhor desempenho global no processo de detecção. Com relação à classificação automática de oscilografias, propõe-se uma nova abordagem incluindo um estágio dedicado à detecção de padrões não inseridos no aprendizado prévio do classificador, denominados de novidades, além da própria classificação multiclasse normalmente empregada para diferenciar múltiplas classes conhecidas a priori. São testadas abordagens utilizando a detecção de novidades e classificação multiclasse em estágios simultâneos e subsequentes, com base nos classificadores X-Médias, K-Vizinhos-Mais-Próximos e Representação de Dados Utilizando Vetores Suporte com diferentes formulações, além do próprio classificador multiclasse baseado em Máquinas de Vetor Suporte. Adicionalmente, é proposto um tratamento aos padrões considerados como novidades, com o intuito de fornecer informações ao especialista sobre as similaridades existentes entre os padrões desse conjunto. Para realizar esse processo, optou-se por utilizar modelos de agrupamento automático. Os resultados finais, principalmente para a base de dados incluindo eventos reais, mostram que é possível obter um desempenho de classificação relevante (acima de 80%) para cada um dos estágios do processo de classificação proposto, o qual inclui a detecção de novidades, a classificação multiclasse e o processamento de padrões classificados como novidades (agrupamento automático).
This work presents new approaches for two of the fundamental steps in automatic waveform analysis in electrical distribution systems: transient time detection and its classification. Two datasets were used to compare and validate the proposed methods. The first is composed by simulated waveforms, by using the Alternative Transient Program, while the second is formed by real data from a monitoring system developed for overhead distribution power lines. The real data present a set of relevant events for the analysis proposed here, mainly due to the variety of events, including lightning-related transients. Regarding transient detection (waveform segmentation), the experiments involve usual segmentation methods, such as Kalman filtering, standard Discrete Wavelet Transform, and autoregressive models, besides two new techniques based on the Teager Energy Operator and Support Vector Data Description. The results obtained on both simulated and real world data demonstrate that the method based on Support Vector Data Description outperforms other methods in the transient identification task. Regarding the automatic waveform classification, a new approach including the detection of classes not defined in the training stage (called novelties) is presented. Also, the classifier is able to discriminate among multiple known classes, normally defined as multi-class classification. Two different approaches are compared, by using multi-class classification and novelty detection in two subsequent stages and in a simultaneous way. The following classifiers were assessed: X-Means, K-Nearest-Neighbors, and Support Vector Data Description with different formulations, besides the Support Vector Machine for multi-class classification. Furthermore, a technique for the post-processing of the novelties is presented, in order to provide some useful information for the experts, regarding possible similarities in the novelty set. To accomplish this task, automatic clustering methods were used. The final results, especially for the dataset with real examples, show that it is possible to obtain a relevant classification performance (above 80%) in each one of the three stages of the classification process: multi-class classification, novelty detection, and the post-processing applied to the novelties (automatic clustering).
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Senel, Gunes. "Multigrid method." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494347278971509.
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Ouwehand, Peter. "The power function." Thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/25548.
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The axioms of ZFC provide very little information about the possible values of the power function (i.e. the map K---->2ᴷ). In this dissertation, we examine various theorems concerning the behaviour of the power function inside the formal system ZFC , and we :;hall be p:trticul:trly interested in results which provide eonstraints on the possible values of the power function. Thus most of the results presented here will be consistency results. A theorem of Easton (Theorem 2.3.1) shows that, when restricted to regular cardinals, the power function may take on any reasonable value, and thus a considerable part of this thesis is concerned with the power function on singular cardinals. We also examine the influence of various strong axioms of infinity, and their generalization to smaller cardinals, on the possible behaviour of the power function.
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SOARES, ALBERTO. "A MODEL POWER FLOWS BASED ON THE POWER SUMMATION METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1992. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8982@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOEste trabalho apresenta uma metodologia para o cálculo de Fluxo de Potência em redes radiais através do Método de Soma de Potências, que explora as características dos parâmetros da rede bem como a sua topologia, constituindo- se em um método bastante rápido e robusto. Propõe-se também uma nova metodologia para o controle de tensão na rede através de rotinas de sensibilidade visando a efetuação de manobras ou cortes de carga na rede. São apresentados testes com sistemas realistas.
This work presents a methodology for radial power flows based on the power Summation Method, able to exploit the network particular characteristics in order to achieve accuracy and efficiency. This work also presents a novel model for radial network control based on sensitivity coefficients that evaluate load transfer or curtailment effects on network performance. Some tests with realistic systems are presented.
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Sendrowski, Janek. "Feigenbaum Scaling." Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96635.
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In this thesis I hope to provide a clear and concise introduction to Feigenbaum scaling accessible to undergraduate students. This is accompanied by a description of how to obtain numerical results by various means. A more intricate approach drawing from renormalization theory as well as a short consideration of some of the topological properties will also be presented. I was furthermore trying to put great emphasis on diagrams throughout the text to make the contents more comprehensible and intuitive.
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Tran, Vanthu Thy. "Newton's method as a mean value method." Akron, OH : University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1176739678.
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Thesis (M.S.)--University of Akron, Dept. of Mathematics, 2007."May, 2007." Title from electronic thesis title page (viewed 4/28/2009) Advisor, Ali Hajjafar; Faculty readers, Linda Marie Saliga, Lala Krishna; Department Chair, Joseph W. Wilder; Dean of the College, Ronald F. Levant; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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DITOLLA, ROBERT JOHN. "RANDOM VIBRATION ANALYSIS BY THE POWER SPECTRUM AND RESPONSE SPECTRUM METHODS (WHITE NOISE, FINITE-ELEMENT, VANMARCKE, DENSITY, NASTRAN)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183836.
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Determination of the stresses and displacements which occur in response to random excitations cannot be accomplished by traditional deterministic analysis methods. As the specification of the excitation and the response of the structure become more complex, solutions by direct, closed-form methods require extensive computations. Two methods are presented which can be used in the analysis of structures which are subjected to random excitations. The Power Spectrum Method is a procedure which determines the random vibration response of the structure based upon a frequency response analysis of a structural model. The Response Spectrum Method is a method which is based upon specified forces or displacements as a function of time. A derivation of each of the methods is presented and followed by comparisons of the results which were obtained for single and multiple-degree-of-freedom systems. Assumptions and limitations of the methods are discussed as well as their accuracy over ranges of frequency, damping and loading specification. As a direct application and comparison of the two methods, an analysis of the support system for the primary mirror of the Space Infrared Telescope Facility (SIRTF) has been performed. In addition, a method for the evaluation of the critical damping in a single-degree-of-freedom structure is demonstrated.
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Stewart, Ian 1975. "The rigidity method and applications /." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30748.
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The Inverse Problem of Galois Theory is discussed. In a specific form, the problem asks whether every finite group occurs as a Galois group over Q . An intrinsically group theoretic property called rigidity is described which confirms that many simple groups are Galois groups over Q . Connections between rigidity and geometry are described and applications of rigidity are provided. In particular, after describing some of the theory of groups of Lie type, the rigidity criterion is applied to the exceptional Lie type groups G2(p), for primes p > 5. With the confirmation of a rationality condition, this establishes that G2(p) occurs as a Galois group over Q for all p > 5. Furthermore, the conjugacy classes which arise in the proof of rigidity for G2( p) are explored in detail, in the hope that a new proof might be produced which would illuminate the geometry associated to this rigid situation.
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Wang, Linhong. "NOETHERIAN SKEW POWER SERIES RINGS." Diss., Temple University Libraries, 2008. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/14014.
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MathematicsPh.D.
This dissertation is concerned with noncommutative analogues of formal power series rings in multiple variables. Our motivating examples arises from quantized coordinate rings; the completions of these quantized coordinate rings are iterated noetherian skew power series rings. Our first focus is on $q$-commutative power series rings, having the following form: $R = k_q[[x_1,\ldots,x_n]]$, where $q = (q_{ij})_{n\times n}$ with $q_{ii}=1$ and $q_{ij} = q^{-1}_{ji} \in \k^{\times}$ and where $x_jx_i = q_{ji} x_i x_j$. The corresponding skew Laurent series ring is $L=k_q[[x_1^{\pm 1},\ldots,x_n^{\pm 1}]]$. We first study the ideal structure of $L$. We prove that extension and contraction of ideals produces a bijection between the set of ideals of $L$ and the set of ideals of the center $Z$ of $L$. This bijection further produces a homeomorphism between $\spec L$ and $\spec Z$. Applying the analysis of $L$ to $R$, we prove that the prime spectrum $\spec R$ can be partitioned into finitely many strata each homeomorphic to the prime spectrum of a commutative noetherian ring. The rings $R$ and $L$ are completions, respectively, of the quantum coordinate ring of $n$-space and of the $n$-torus. Our second focus is on power series completions of iterated skew polynomial rings with nonzero derivations. Given an iterated skew polynomial ring $C[y_1;\t_1,\d_1]\ldots [y_n;\t_n,\d_n]$ over a complete local ring $C$ with maximal ideal $\m$, we prove, under suitable assumptions, that the completion at the ideal $\m + \left\langle y_1,y_2,\ldots,y_n\right\rangle$ is an iterated skew power series ring. Under further conditions, this completion is a local, noetherian, Auslander regular domain. Applicable examples include the following quantized coordinate rings: quantum matrices, quantum symplectic spaces, and quantum Euclidean spaces. Results in this dissertation are included in the following two preprints: 1. Prime ideals of $q$-commutative power series rings (joint with E. S. Letzter), submitted for publication. 2. Completions of quantum coordinate rings, to appear in Proceedings of the American Mathematical Society.
Temple University--Theses
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Meegahawatte, Danushka Hansitha. "A design method for specifying power sources for hybrid power systems." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1215/.
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Many efforts have been made in recent years to address issues surrounding the use of fossil fuels for energy. However, it must be conceded that world’s dependence on fossil fuels cannot cease overnight. In reality, the switch is expected to be a relatively slow migration of technologies over many decades. During this transition period the world will need bridging technologies to aid in the transition to alternate energy sources. One such technology, which shows much promise in boosting energy efficiency while reducing emissions and costs, is the adoption of hybrid power systems. This thesis investigates the motives behind seeking alternate energy sources and discusses the future need to move away from fossil fuels and the likely role hybrid power systems will play in the future. A general outline of a hybrid power system is presented, and its key subsystems identified and discussed, paying attention to power generation, energy storage technologies and the performance of these systems. A novel method of specifying the power sources in bespoke hybrid power systems are presented. A custom software tool aimed at evaluating how different hardware configurations and output duty cycles affect the performance of a hybrid power system is then presented and used in several case studies to investigate the effectiveness of the presented method in specifying power sources for a given application. It was found that the hardware, output application and control strategy of a hybrid power system affects the overall performance of the system. Furthermore, if the output duty cycle of a hybrid power system is repetitive and predictable in nature, it was found that the hardware and control strategy of the system can be fine-tuned using simple techniques to optimise the overall system configuration and performance.
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Bokka, Naveen. "Comparison of Power Flow Algorithms for inclusion in On-line Power Systems Operation Tools." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1237.
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The goal of this thesis is to develop a new, fast, adaptive load flow algorithm that "automatically alternates" numerical methods including Newton-Raphson method, Gauss-Seidel method and Gauss method for a load flow run to achieve less run time. Unlike the proposed method, the traditional load flow analysis uses only one numerical method at a time. This adaptive algorithm performs all the computation for finding the bus voltage angles and magnitudes, real and reactive powers for the given generation and load values, while keeping track of the proximity to convergence of a solution. This work focuses on finding the algorithm that uses multiple numerical techniques, rather than investigating programming techniques and programming languages. The convergence time is compared with those from using each of the numerical techniques. The proposed method is implemented on the IEEE 39-bus system with different contingencies and the solutions obtained are verified with PowerWorld Simulator, a commercial software for load flow analysis.
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Tam, Laying. "The general Euler-Borel summability method /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683756124139.
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Kasikci, Ismail. "A new method for power quality improvement." Thesis, Brunel University, 2000. http://bura.brunel.ac.uk/handle/2438/5802.
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A new control method for active power filters in conjunction with a passive filter circuit are presented and analysed in this thesis. A new technique for load modelling is introduced in order to enable the design of compensators to improve the power factor and to reduce harmonic levels in electrical power systems. The principles of analysis, design, operation and control of the new circuit equipped with IGBTs are presented. This enables the compensation of rapidly changing loads and reactive power. A special circuit equipped with IGBTs is able to compensate for the reactive power and harmonic currents of different orders. The important aspect of the present work is based on the compensator control circuit for power factor correction and harmonic elimination, and its application. This new configuration improves the rating of the active power filter, reducing power losses in the switches compared to existing and newly developed active filters. Furthermore, it is very stable in operation and much faster by a factor of 20. The thesis also presents a detailed mathematical modelling of the proposed system with frequency and time domain equations. The frequency response of the proposed system is also discussed. This new proposal has been checked using a dedicated software simulation program, which was specifically developed for this purpose. An experimental set-up has been designed and implemented in order to apply the new method using IGBTs as well as some other devices. This thesis also presents a critical literature survey, which provides a critical overview of previous work relevant to the power quality improvement reactive power compensation and active filtering.
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Gopalan, Sriram. "A method of low power SRAM design /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1546779941&sid=19&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Dandachi, Najib H. "Network flow method for power system analysis." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47398.
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She, Chunfeng. "A mathematical model for power derivatives." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3297110.
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Thesis (Ph.D.)--Indiana University, Dept. of Mathematics, 2007.Title from dissertation home page (viewed Sept. 29, 2008). Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1045. Adviser: Victor W. Goodman.
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Mühlpfordt, Tillmann [Verfasser], and V. [Akademischer Betreuer] Hagenmeyer. "Uncertainty Quantification via Polynomial Chaos Expansion – Methods and Applications for Optimization of Power Systems / Tillmann Mühlpfordt ; Betreuer: V. Hagenmeyer." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1203211872/34.
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Pigno, Vincent. "Prime power exponential and character sums with explicit evaluations." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/18277.
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Doctor of PhilosophyDepartment of Mathematics
Christopher Pinner
Exponential and character sums occur frequently in number theory. In most applications one is only interested in estimating such sums. Explicit evaluations of such sums are rare. In this thesis we succeed in evaluating three types of sums when p is a prime and m is sufficiently large. The twisted monomial sum, the binomial character sum, and the generalized Jacobi sum. We additionally show that these are all sums which can be expressed in terms of classical Gauss sums.
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lin, zhipeng. "Computational Methods in Financial Mathematics Course Project." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/1192.
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This course project is made up of two parts. Part one is an investigation and implementation of pricing of financial derivatives using numerical methods for the solution of partial differential equations. Part two is an introduction of Monte Carlo methods in financial engineering. The name of course is MA573:Computational Methods in Financial Mathematics, spring 2009, given by Professor Marcel Blais.
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Pereira, Rajesh. "Interpolation of operators using Peetre's K-method." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44243.pdf.
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Lagrange, John. "Power Series Solutions to Ordinary Differential Equations." TopSCHOLAR®, 2001. http://digitalcommons.wku.edu/theses/672.
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In this thesis, the reader will be made aware of methods for finding power series solutions to ordinary differential equations. In the case that a solution to a differential equation may not be expressed in terms of elementary functions, it is practical to obtain a solution in the form of an infinite series, since many differential equations which yield such a solution model an actual physical situation. In this thesis, we introduce conditions that guarantee existence and uniqueness of analytic solutions, both in the linear and nonlinear case. Several methods for obtaining analytic solutions are introduced as well. For the sake of pure mathematics, and particularly in the applications involving these differential equations, it is useful to find a radius of convergence for a power series solution. For these reasons, several methods for finding a radius of convergence are given. We will prove all results in this thesis.
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Ganter, Nora 1976. "Orbifold genera, product formulas and power operations." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30147.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2004.Includes bibliographical references (p. 53-56).
There is a formula by the string theorists Dijkgraaf, Moore, Verlinde and Verlinde, expressing the orbifold elliptic genus of the symmetric powers of an almost complex manifold M in terms of the elliptic genus of M itself. We show that from the point of view of elliptic cohomology an analogous p-typical statement follows as an easy corollary from the fact that the map of spectra corresponding to the genus preserves power operations. We define higher chromatic versions of the notion of orbifold genus, involving h-tuples rather than pairs of commuting elements. Using homotopy theoretic methods we are able to prove an integrality result and show that our definition is independent of the representation of the orbifold. Our setup is so simple, that it allows us to prove DMVV-type product formulas for these higher chromatic orbifold genera in the same way that the product formula for the topological Todd genus is proved. More precisely, we show that any genus induced by an H[omega]-map into one of the Morava-Lubin-Tate cohomology theories Eh has such a product formula and that the formula depends only on h and not on the genus. Since the complex H[omega]-genera into Eh have been classified in [And95], a large family of genera to which our results apply is completely understood. Loosely speaking, our result says that some Borcherds lifts have a well-known homotopy theoretic refinement, namely total symmetric powers in elliptic cohomology.
by Nora Ganter.
Ph.D.
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Desjardins, Craig J. (Craig Jeffrey). "Monomization of power Ideals and parking functions." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/64612.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 47-48).
A zonotopal algebra is the quotient of a polynomial ring by an ideal generated by powers of linear forms which are derived from a zonotope, or dually it's hyperplane arrangement. In the case that the hyperplane arrangement is of Type A, we can rephrase the definition in terms of graphs. Using the symmetry of these ideals, we can find monomial ideals which preserve much of the structure of the zonotopal algebras while being computationally very efficient, in particular far faster than Gröbner basis techniques. We extend this monomization theory from the known case of the central zonotopal algebra to the other two main cases of the external and internal zonotopal algebras.
by Craig J. Desjardins.
Ph.D.
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Eriksson, Måns. "A simulation method for skewness correction." Thesis, Uppsala University, Department of Mathematics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-120037.
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