Дисертації з теми "Complex power systems"
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Zhou, Keming. "Computation of asymmetric fault current in complex power systems." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287924.
Повний текст джерелаBremner, Jonathan James. "Complex torque coefficient analysis of multi-device power systems." Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362955.
Повний текст джерелаBerry, T. "Real time simulation of complex power systems using parallel processors." Thesis, University of Bath, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328841.
Повний текст джерелаLiu, Zifan. "Complex systems and health systems, computational challenges." Thesis, Versailles-St Quentin en Yvelines, 2015. http://www.theses.fr/2015VERS001V/document.
Повний текст джерелаThe eigenvalue equation intervenes in models of infectious disease prop- agation and could be used as an ally of vaccination campaigns in the ac- tions carried out by health care organizations. The epidemiological model- ing techniques can be considered by analogy, as computer viral propagation which depends on the underlying graph status at a given time. We point out PageRank as method to study the epidemic spread and consider its calcula- tion in the context of small-world phenomenon. A parallel implementation of multiple implicitly restarted Arnoldi method (MIRAM) is proposed for calculating dominant eigenpair of stochastic matrices derived from very large real networks. Their high damp- ing factor makes many existing algorithms less efficient, while MIRAM could be promising. We also propose in this thesis a parallel graph gen- erator that can be used to generate distributed synthesized networks that display scale-free and small-world structures. This generator could serve as a testbed for graph related algorithms. MIRAM is implemented within the framework of Trilinos, targeting big data and sparse matrices representing scale-free networks, also known as power law networks. Hypergraph partitioning approach is employed to minimize the communication overhead. The algorithm is tested on a nation wide cluster of clusters Grid5000. Experiments on very large networks such as twitter and yahoo with over 1 billion nodes are conducted. With our parallel implementation, a speedup of 27× is met compared to the sequential solver
Oliver, John M. "Multi-objective optimisation methods applied to complex engineering systems." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/11707.
Повний текст джерелаPezdirc, Marjetka. "The terrorism complex." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/19149.
Повний текст джерелаCase, Denise Marie. "Engineering complex systems with multigroup agents." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/19045.
Повний текст джерелаComputing and Information Sciences
Scott A. DeLoach
As sensor prices drop and computing devices continue to become more compact and powerful, computing capabilities are being embedded throughout our physical environment. Connecting these devices in cyber-physical systems (CPS) enables applications with significant societal impact and economic benefit. However, engineering CPS poses modeling, architecture, and engineering challenges and, to fully realize the desired benefits, many outstanding challenges must be addressed. For the cyber parts of CPS, two decades of work in the design of autonomous agents and multiagent systems (MAS) offers design principles for distributed intelligent systems and formalizations for agent-oriented software engineering (AOSE). MAS foundations offer a natural fit for enabling distributed interacting devices. In some cases, complex control structures such as holarchies can be advantageous. These can motivate complex organizational strategies when implementing such systems with a MAS, and some designs may require agents to act in multiple groups simultaneously. Such agents must be able to manage their multiple associations and assignments in a consistent and unambiguous way. This thesis shows how designing agents as systems of intelligent subagents offers a reusable and practical approach to designing complex systems. It presents a set of flexible, reusable components developed for OBAA++, an organization-based architecture for single-group MAS, and shows how these components were used to develop the Adaptive Architecture for Systems of Intelligent Systems (AASIS) to enable multigroup agents suitable for complex, multigroup MAS. This work illustrates the reusability and flexibility of the approach by using AASIS to simulate a CPS for an intelligent power distribution system (IPDS) operating two multigroup MAS concurrently: one providing continuous voltage control and a second conducting discrete power auctions near sources of distributed generation.
Johan, Fredrik Raak. "Data-driven analysis of wind power and power system dynamics via Koopman mode decomposition". Kyoto University, 2017. http://hdl.handle.net/2433/227628.
Повний текст джерелаHa, Dinh Truc. "Line outage vulnerabilities of power systems : models and indicators." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT018/document.
Повний текст джерелаThe vulnerability of electrical systems is one of the problems related to their complexity. It has received increasing attention from researchers in recent decades. Despite this, the fundamental phenomena that govern the vulnerability of the system are still not well understood.Understanding how the vulnerability of power systems emerges from their complex organization is, therefore, the main motivation of the present work. It proposes the definition of a standard method to assess the vulnerability of power systems and identify their most critical elements. The method enables a better understanding of the links between the topology of the grid and the line outage vulnerabilities.The first part of this research work offers a critical review of literature approaches used to assess system vulnerability. The results provided by these approaches for four IEEE test systems are confronted to a reference contingency analysis using AC power flow calculations. From these analyses, pros and cons of each approach are outlined. An improved method for assessment of system vulnerability to line outages is defined from this confrontation. It is based on DC load flow and graph theory.The second part proposes a new approach based on spectral graph theory and solving of DC power flow to identify how system vulnerability and critical components emerge from the power network topology
Popli, Nipun. "Multi-layered Energy Conversion and Frequency Control in Complex Electric Power Systems." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/916.
Повний текст джерелаCoey, Charles A. "Complexity and Coordination: Power-Law Scaling in the Temporal Coordination of Complex Systems." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439282201.
Повний текст джерелаHamm, Andreas. "Methodology and Modelling Approach for Strategic Sustainability Analysis of Complex Energy-Environment Systems." Thesis, University of Canterbury. Mechanical Engineering, 2007. http://hdl.handle.net/10092/1207.
Повний текст джерелаBhang, Kon Joon. "Remote Sensing Approach for Hydrologic Assessments of Complex Lake Systems." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1212787335.
Повний текст джерелаIVANOVA, OLGA. "Development of Decision Support System for Optimization of Dams’ Management on Complex River Systems." Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1010257.
Повний текст джерелаSECCHI, SIMONE. "Simulating complex multi-core computing systems: techniques and tools." Doctoral thesis, Università degli Studi di Cagliari, 2011. http://hdl.handle.net/11584/266327.
Повний текст джерелаGeorge-Williams, H. "Efficient reliability modelling & analysis of complex systems with application to nuclear power plant safety." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3027659/.
Повний текст джерелаKandia, Effrosyni <1979>. "Evaluation of Human Exposure to Magnetic Fields Generated by Electric Power Systems in Complex Configurations." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/6101/1/PhD_Thesis_-_KANDIA.Pdf.
Повний текст джерелаKandia, Effrosyni <1979>. "Evaluation of Human Exposure to Magnetic Fields Generated by Electric Power Systems in Complex Configurations." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/6101/.
Повний текст джерелаDeng, Weibing. "On the ranking property and underlying dynamics of complex systems." Thesis, Le Mans, 2013. http://www.theses.fr/2013LEMA1010/document.
Повний текст джерелаRanking procedures are widely used to describe the phenomena in many differentfields of social and natural sciences, e.g., sociology, economics, linguistics, demography,physics, biology, etc. In this dissertation, we dedicated to study the ranking propertiesand underlying dynamics embedded in complex systems. In particular, we focused onthe scores/prizes ranking in sports systems and the words/characters usage ranking inhuman languages. The aim is to understand the mechanisms behind these issues byusing the methods of statistical physics, Bayesian statistics and agent-based modeling.The concrete results concern the following aspects.We took up an interesting topic on the scores/prizes ranking in sports systems, andanalyzed 40 data samples in 12 different sports fields. We found the striking similaritiesin different sports, i.e., the distributions of scores/prizes follow the universal powerlaws. We also showed that the data yielded the Pareto principle extensively observedin many social systems: 20% of the players accumulate 80% of the scores and money.For the tennis head-to-head data, we revealed that when two players compete, theprobability that the higher-ranked player will win is related to the rank difference ofthe two opponents. In order to understand the origins of the universal scaling, weproposed an agent-based model, which can simulate the competitions of players indifferent matches, and results from our simulations are consistent with the empiricalfindings. Extensive simulation studies indicate that the model is quite robust withrespect to the modifications of some parameters.Zipf’s law is the major regularity of statistical linguistics that served as a prototypefor the rank-frequency relations and scaling laws in natural sciences. We investigatedseveral English texts, clarified the valid range of Zipf’s law, and found this valid rangeincreases upon mixing different texts. Based on the latent semantic analysis, we proposeda probabilistic model, in which we assumed that the words are drawn into thetext with random probabilities, while their apriori density relates, via Bayesian statistics,to the general features of mental lexicon of the author who produced the text. Ourmodel explained the Zipf’s law together with the limits of its validity, its generalizationto high and low frequencies and hapax legomena. In another work, we specified the rank-frequency relations for Chinese characters. We chose to study the short texts first, since for the sake of the rank-frequency analysis,long texts are just mixtures of shorter, thematically homogenous pieces. Our resultsshowed that the Zipf’s law for Chinese characters perfectly holds for sufficiently shorttexts (few thousand different characters), and the scenario of its validity is similar tothat for short English texts. We argued long Chinese texts display a two-layer, hierarchicstructure: power-law rank-frequency characters (first layer) and the exponentialones (second layer). The previous results on the invalidity of the Zipf’s law for longtexts are accounted for by showing that in between of the Zipfian range and the regionof very rare characters (hapax legomena) there emerges a range of ranks, wherethe rank-frequency relation is approximately exponential. From comparative analysisof rank-frequency relations for Chinese and English, we suggested the characters playfor Chinese writers the same role as the words for those writing within alphabeticalsystems
Wärja, Mathias. "Maintenance management of complex industrial systems : a methodology for renewal strategies." Doctoral thesis, KTH, School of Electrical Engineering (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-542.
Повний текст джерелаFor complex technical systems in the electricity and pulp and paper industries, maintenance management addresses how to exploit physical assets in the most profitably way. This is a difficult task that requires taking into consideration parameters of totally different natures – e.g. reliability data, operating costs, condition of technical systems, the environment and rules and regulation.
An incorrect estimate of a residual lifetime can result in a premature renewal with accompanying high capital costs. If, however, renewal is delayed, a breakdown may occur which can cause major damage to technical equipment and a loss of income due to outages. Because of the complexity of many technical systems, it can be hard to select adequate data to use when making decisions about renewal strategies. To cope with this, one approach is to use less detailed models that are operated by skilled analysts.
This work demonstrates the advantage of such an approach by proposing two methods applied in a joint methodology that has its origins in RCM. The methodology consists of Dynamic Lifetime Model (DLA) and the Condition Based Index (CBI). The DLA method copes with the financial risk associated with the point in time for when a renewal is carried out and the CBI method uses critical parameters to estimate the condition of a technical system. The two methods together create a quantitative connection between reliability, maintenance and financial risk. A case study based validation of the methodology was carried out at SCA Ortvikens paper mill on a refiner system and Forsmark nuclear power plant. Lessons learned from the case study showed that the methodology could be used to identify which components could cause costly breakdown. By using the methodology a manager gets a decision support tool for estimating short-term and long-term consequences of decisions regarding maintenance management in order to maximize utility of the system concerned
Öztürk, Esma. "WAKE INDUCED POWER DEFICIT ANALYSIS ON WIND TURBINES IN FORESTED MODERATELY COMPLEX TERRAIN USING SCADA DATA." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-346639.
Повний текст джерелаJiao, Xiangqing. "Fault Location in Transmission Systems Using Synchronized Measurements." UKnowledge, 2017. http://uknowledge.uky.edu/ece_etds/100.
Повний текст джерелаGensollen, Nicolas. "Modeling and optimizing a distributed power network : a complex system approach of the "prosumer" management in the smart grid." Thesis, Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0019/document.
Повний текст джерелаThis thesis is devoted to the study of agents called prosumers because they can, from renewable, both produce and consume electricity. If their production exceeds their own needs, they are looking to sell their surplus on electricity markets. We propose to model these prosumers from meteorological data, which has allowed us to highlight non trivial spatial and temporal correlations. This is of great importance for aggregators that form portfolios of equipments to sell services to the network operator. As an aggregator is bound by a contract with the operator, it can be subject to penalties if it does not fulfill its role. We show that these correlations impact the stability of aggregates, and therefore the risk taken by the aggregators. We propose an algorithm minimizing the risk of the aggregations, while maximizing the expected gain. The placement of storage devices in a network where generators and loads are stochastic and not fixed is complex. We propose to answer this question with control theory. We model the electrical system as a network of coupled oscillators, whose phase angles dynamics is an approximation of the actual dynamics of the system. The goal is to find the subset of nodes in the graph that, during a disturbance of the system, allows returning to equilibrium if the right signals are injected and this with a minimum energy. We propose an algorithm to find a near optimal placement to minimize the average energy control
GIUFFRIDA, STEFANIA. "The role of the power law distributions in describing social complex systems. Implications in the field of knowledge performance assessment." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2013. http://hdl.handle.net/2108/204149.
Повний текст джерелаMcAndrew, Thomas Charles. "Weighted Networks: Applications from Power grid construction to crowd control." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/668.
Повний текст джерелаFourie, Tamryn-Lee. "The application of system dynamics to resource allocation in international NGOs: exploring and modelling power inequalities whilst increasing efficiencies in complex international NGO management systems." Master's thesis, Faculty of Science, 2018. http://hdl.handle.net/11427/30148.
Повний текст джерелаMUREDDU, MARIO. "A novel complex system approach for the determination of renewable energy sources impact on electricity infrastructures." Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266793.
Повний текст джерелаAbell, Barry J. "Planning concepts to sustain, develop, and test complex naval combat systems at the Surface Combat Systems Center, Wallops Island, Virginia." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FAbell.pdf.
Повний текст джерелаThesis Advisor(s): Scott Carlson, Benjamin Roberts. Includes bibliographical references (p. 145-152) Also available online.
Schinaider, Sidney Jorge. "Distribuição de lei de potência gradualmente truncada aplicada na educação : vestibular da Academia da Força Aérea /." Rio Claro : [s.n.], 2006. http://hdl.handle.net/11449/91932.
Повний текст джерелаBanca: Gerson Antonio Santarine
Banca: Osvaldo Missiato
Resumo: Educação e aprendizado são assuntos de grande importância para a sociedade em vista do desenvolvimento tecnológico e do progresso social. No presente trabalho analisamos a distribuição estatística das notas dos candidatos ao vestibular (Exame de Admissão) da Academia da Força Aérea, situada em Pirassununga, Estado de São Paulo Brasil, onde se formam os Oficiais da Aeronáutica (Força Aérea Brasileira), entre os anos de 1999 a 2004, em busca de algumas características que indiquem o processo de aprendizagem em cada disciplina do vestibular. O exame de admissão consta de 4 disciplinas: Física, Matemática, Inglês e Português, todos com questões objetivas. Os candidatos melhor classificados são selecionados de acordo com o número de vagas determinado pelo Comando da Aeronáutica. Notou-se, claramente, que, nas disciplinas Física, Matemática e Inglês, as notas obedecem a uma distribuição do tipo Lei de Potência Gradualmente Truncada, como também foi observado anteriormente nas disciplinas, em conjunto, de Ciências Exatas e Biológicas. Na disciplina Português as notas obedecem a uma distribuição normal, resultado que se explica, considerando-se a dependência dos assuntos dados na área de Física, Matemática e Inglês (língua estrangeira) aos assuntos ministrados anteriormente, enquanto em Português, (língua materna) cada capítulo é relativamente independente. Também apresentamos sugestão para melhorar o ensino de ciências e matemáticas.
Abstract: Science and Mathematic Education is a subject of great importance for the society in sight of recent technological and social program. In the present work, we study the statistical distribution of the marks obtained by the candidates in entrance examination of Air Force Academy, which prepare officers for Brazilian Air Force and is situated at Pirassununga São Paulo, in the period of 1999-2004. Our object is to find some characteristics of the process of learning in various disciplines. The admission examination consist of four disciplines; Physics, Mathematics, English and Portuguese. The candidates are selected in accordance with the merit list in the examination and number of seats available as determined by the Air Force Command. We showed that in the discipline of Physics, Mathematics and English, the distribution of marks obtained is in accordance with Gradually Truncated Power Law as also have been reported earlier in Exact and Biological Sciences in University entrance examination. In Portuguese the Distribution is Normal. We explained these results considering importance of the understanding of material given previously to understand a new chapter in area of Physics, Mathematics and English as our foreign language. In the case of Portuguese (Native Language), each chapter is relatively independent and thus not require knowledge of previous chapters. We also presented some suggestions to improve the science and Mathematics Education at High School level.
Mestre
Schinaider, Sidney Jorge [UNESP]. "Distribuição de lei de potência gradualmente truncada aplicada na educação: vestibular da Academia da Força Aérea." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/91932.
Повний текст джерелаEducação e aprendizado são assuntos de grande importância para a sociedade em vista do desenvolvimento tecnológico e do progresso social. No presente trabalho analisamos a distribuição estatística das notas dos candidatos ao vestibular (Exame de Admissão) da Academia da Força Aérea, situada em Pirassununga, Estado de São Paulo Brasil, onde se formam os Oficiais da Aeronáutica (Força Aérea Brasileira), entre os anos de 1999 a 2004, em busca de algumas características que indiquem o processo de aprendizagem em cada disciplina do vestibular. O exame de admissão consta de 4 disciplinas: Física, Matemática, Inglês e Português, todos com questões objetivas. Os candidatos melhor classificados são selecionados de acordo com o número de vagas determinado pelo Comando da Aeronáutica. Notou-se, claramente, que, nas disciplinas Física, Matemática e Inglês, as notas obedecem a uma distribuição do tipo Lei de Potência Gradualmente Truncada, como também foi observado anteriormente nas disciplinas, em conjunto, de Ciências Exatas e Biológicas. Na disciplina Português as notas obedecem a uma distribuição normal, resultado que se explica, considerando-se a dependência dos assuntos dados na área de Física, Matemática e Inglês (língua estrangeira) aos assuntos ministrados anteriormente, enquanto em Português, (língua materna) cada capítulo é relativamente independente. Também apresentamos sugestão para melhorar o ensino de ciências e matemáticas.
Science and Mathematic Education is a subject of great importance for the society in sight of recent technological and social program. In the present work, we study the statistical distribution of the marks obtained by the candidates in entrance examination of Air Force Academy, which prepare officers for Brazilian Air Force and is situated at Pirassununga São Paulo, in the period of 1999-2004. Our object is to find some characteristics of the process of learning in various disciplines. The admission examination consist of four disciplines; Physics, Mathematics, English and Portuguese. The candidates are selected in accordance with the merit list in the examination and number of seats available as determined by the Air Force Command. We showed that in the discipline of Physics, Mathematics and English, the distribution of marks obtained is in accordance with Gradually Truncated Power Law as also have been reported earlier in Exact and Biological Sciences in University entrance examination. In Portuguese the Distribution is Normal. We explained these results considering importance of the understanding of material given previously to understand a new chapter in area of Physics, Mathematics and English as our foreign language. In the case of Portuguese (Native Language), each chapter is relatively independent and thus not require knowledge of previous chapters. We also presented some suggestions to improve the science and Mathematics Education at High School level.
Menck, Peter-Johannes. "How wires shape volumes." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2014. http://dx.doi.org/10.18452/16930.
Повний текст джерелаThis thesis addresses the question how the stability of a power grid depends on the network topology. Stability is assessed here by means of basin stability, a nonlocal and nonlinear inspection scheme that allows to quantify how stable a power grid is against large perturbations. Networked systems are characterized using the instruments of complex network theory. A rigorous definition of basin stability is provided. Then, basin stability is applied once in an abstract and once in a more applied way. The abstract approach is motivated by the fact that power grids rely on the synchronous operation of their components, and focusses on the problem how general dynamical networks should be structured to support a stable synchronous state. It turns out that networks with maximum basin stability are located at the opposite end of a certain network-theoretical spectrum than networks optimal with respect to local stability. This suggests that, during the evolution of synchronizing networks, the optimization for local stability and the simultaneous optimization for nonlocal stability have acted as opposing forces. The more applied approach draws on a power grid model from the engineering literature. A component-wise version of basin stability is used to assess how a grid''s degree of stability against large single-node perturbations is influenced by certain patterns in the wiring topology. Simulations in an ensemble of power grids yield various statistics that all support one main finding: The widespread and cheapest of all connection schemes, so-called dead ends and dead trees, strongly diminish stability. The inverse is also true: `Healing'' dead ends by addition of transmission lines substantially enhances stability. This indicates a basic design principle for future power grids: avoid dead ends.
Thorup, Pernille. "Strategy-making in a senior leadership team in the public sector in Denmark : taking experience seriously as co-creation, conflict and paradox." Thesis, University of Hertfordshire, 2016. http://hdl.handle.net/2299/17226.
Повний текст джерелаMasca, Gregoria Magda Ticona. "Um estudo sobre raios de estabilidade real e complexo e valores singulares estruturados." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-31102017-102818/.
Повний текст джерелаIn this work, two techniques of robust control (LQG/LTR) and LMI), applied to a power electric system, are available via stability radii of the system. The structured uncertainties of the nominal model are considered in both designs. A set of models is generated considering the combinations of the parametric uncertainties. The structured singular values of both systems are analysed.
Barroca, Neto ?lvaro. "Simula??o de fluxo de fluidos em meios porosos desordenados uma an?lise de efeito de escala na estimativa da permeabilidade e do coeficiente de arrasto." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13015.
Повний текст джерелаThe present study provides a methodology that gives a predictive character the computer simulations based on detailed models of the geometry of a porous medium. We using the software FLUENT to investigate the flow of a viscous Newtonian fluid through a random fractal medium which simplifies a two-dimensional disordered porous medium representing a petroleum reservoir. This fractal model is formed by obstacles of various sizes, whose size distribution function follows a power law where exponent is defined as the fractal dimension of fractionation Dff of the model characterizing the process of fragmentation these obstacles. They are randomly disposed in a rectangular channel. The modeling process incorporates modern concepts, scaling laws, to analyze the influence of heterogeneity found in the fields of the porosity and of the permeability in such a way as to characterize the medium in terms of their fractal properties. This procedure allows numerically analyze the measurements of permeability k and the drag coefficient Cd proposed relationships, like power law, for these properties on various modeling schemes. The purpose of this research is to study the variability provided by these heterogeneities where the velocity field and other details of viscous fluid dynamics are obtained by solving numerically the continuity and Navier-Stokes equations at pore level and observe how the fractal dimension of fractionation of the model can affect their hydrodynamic properties. This study were considered two classes of models, models with constant porosity, MPC, and models with varying porosity, MPV. The results have allowed us to find numerical relationship between the permeability, drag coefficient and the fractal dimension of fractionation of the medium. Based on these numerical results we have proposed scaling relations and algebraic expressions involving the relevant parameters of the phenomenon. In this study analytical equations were determined for Dff depending on the geometrical parameters of the models. We also found a relation between the permeability and the drag coefficient which is inversely proportional to one another. As for the difference in behavior it is most striking in the classes of models MPV. That is, the fact that the porosity vary in these models is an additional factor that plays a significant role in flow analysis. Finally, the results proved satisfactory and consistent, which demonstrates the effectiveness of the referred methodology for all applications analyzed in this study.
O presente trabalho proporciona uma metodologia que d? um car?ter preditivo ?s simula??es computacionais baseadas em modelos detalhados da geometria porosa de um meio. N?s utilizando o software FLUENT para investigar o escoamento de um fluido newtoniano viscoso atrav?s de um meio fractal aleat?rio que simplifica um meio poroso desordenado bidimensional representando um reservat?rio de petr?leo. Este modelo fractal ? formado por obst?culos de diversos tamanhos, cuja fun??o de distribui??o segue uma lei de pot?ncia, onde o expoente ? definido como sendo a dimens?o fractal de fracionamento Dff do modelo e caracteriza o processo de fragmenta??o desses obst?culos. Eles s?o aleatoriamente dispostos em um canal retangular. O processo de modelagem incorpora conceitos modernos, leis de escala, para analisar a influ?ncia das heterogeneidades encontradas nos campos da porosidade e da permeabilidade de tal maneira que se possa caracterizar o meio em fun??o de suas propriedades fractais. Este procedimento permite analisar numericamente as medidas da permeabilidade k e do coeficiente de arrasto Cd propondo rela??es, tipo lei de pot?ncia, para essas propriedades sobre v?rios esquemas de modelagem. O prop?sito desta pesquisa ? estudar a variabilidade proporcionada por estas heterogeneidades onde o campo de velocidade e outros detalhes da din?mica dos fluidos viscosos s?o obtidos resolvendo numericamente as equa??es da continuidade e de Navier-Stokes no n?vel de poros e observar como a dimens?o fractal de fracionamento do modelo pode afetar as suas propriedades hidrodin?micas. Neste estudo foram consideradas duas classes de modelos, modelos com porosidade constante, MPC, e modelos com porosidade vari?vel, MPV. Os resultados permitiram-nos encontrar rela??es num?ricas entre a permeabilidade, coeficiente de arrasto e os par?metros geom?tricos do modelo. Com base nestes resultados num?ricos propusemos rela??es de escala envolvendo os par?metros relevantes do fen?meno. Nesta pesquisa foram determinadas equa??es anal?ticas para Dff em fun??o dos par?metros geom?tricos dos modelos. Constatamos tamb?m uma rela??o entre a permeabilidade e o coeficiente de arrasto onde uma ? inversamente proporcional ? outra. Quanto ? diferen?a de comportamento ela ? mais marcante nas classes de modelos MPV. Isto ?, o fato da porosidade variar nestes modelos constitui um fator adicional que desempenha um papel significativo na an?lise de fluxo. Finalmente, os resultados encontrados se mostraram consistentes e satisfat?rios, o que demonstra a efic?cia da referida metodologia para todas as aplica??es analisadas nesta pesquisa.
Rodney, Elodie. "Développement d’une méthode de gestion des risques de projet et d’aide à la décision en contexte incertain : application au domaine des énergies renouvelables." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0399/document.
Повний текст джерелаRisk is an inherent property of each project. Indeed, any project faces, throughout its whole life cycle, numerous risks. Those risks can have an internal or an external origin. Be able to control risks is a crucial stake for the project success. Many risk management tools have been developed, but have the recurring weakness of representing only the project and treating the risk in isolation. Risks affect the project and are generated by the project itself. So, it is necessary to consider the numerous and complex interactions between project, environment and risks.The work carried out aims to develop a risk management method suitable for all types of projects and more particularly for projects of the competitive field of renewable energies.This method relies on a formal framework, as well as on application tools to optimize project risk management. Indeed, a modeling framework which supports the method and aims to facilitate the modeling of the project as a complex system has been developed. Moreover, the representation of the interactions and the decision making have been allowed by the nature of the attributes characterizing the entities of the project and its environment and the different models for evaluation, interpretation and selection of alternatives. This method was adapted to the uncertain context. For this purpose, uncertainties have been identified and described via the realization of a data base on risk factors. Then, uncertainties have been formalized, propagated and evaluated
Wang, Zhuoyang. "Application of Complex Network Theory in Power System Security Assessment." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/17367.
Повний текст джерелаOliveira, Josà Dickson AraÃjo de. "Evaluation of the operation of the HVDC system of Madeira River complex interconnection to the Southern Region of the brazilian electric system." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15766.
Повний текст джерелаEste trabalho propÃe um modelo do sistema de transmissÃo HVDC do Complexo do Rio Madeira, desenvolvido no ambiente PSCAD/EMTDC e baseado no projeto disponibilizado pela Empresa de Pesquisa EnergÃtica - EPE na fase de concessÃo das instalaÃÃes. O modelo construÃdo à avaliado por meio da comparaÃÃo entre os resultados de simulaÃÃo e os dados reais de ocorrÃncias no Sistema Interligado Nacional - SIN que envolveram o complexo. O HVDC do Rio Madeira possui capacidade total de conversÃo de 7.100 MW, e transporta a energia gerada nas usinas hidroelÃtricas de Santo AntÃnio e Jirau, prÃximas a Porto Velho, para centros de carga locais e para o sudeste do Brasil, chegando à subestaÃÃo Araraquara, no estado de SÃo Paulo, atravÃs de duas linhas em corrente contÃnua de 2.350 km de extensÃo. O sistema à composto por dois blocos back-to-back (anti-paralelo) de 400 MW cada, com estaÃÃes conversoras comutadas por capacitores, para atender as cargas dos estados de RondÃnia e Acre, e dois elos bipolares de 3.150 MW cada, constituÃdos de conversores fonte de corrente de 12 pulsos com comutaÃÃo natural de linha, para transmissÃo de energia para o sudeste do paÃs. Os resultados da comparaÃÃo entre os dados reais e a simulaÃÃo mostraram que as diferenÃas percentuais entre grandezas avaliadas se mantiveram dentro de limites satisfatÃrios, podendo-se concluir que o modelo construÃdo foi considerado validado.
Daza, Enrique Acha. "Modelling of power system transformers in the complex conjugate harmonic space." Thesis, University of Canterbury. Electrical Engineering, 1988. http://hdl.handle.net/10092/5450.
Повний текст джерелаMoran, José. "Statistical physics and anomalous macroeconomic fluctuations." Thesis, Paris, EHESS, 2020. http://www.theses.fr/2020EHES0106.
Повний текст джерелаHow do microscopic perturbations at the level of an individual grow to become macroscopic fluctuations of the whole economy? Despite decades of effort, this puzzle remains open. In this work, I tackle this problem using methods and techniques from statistical physics. Beginning with a thorough analysis of power law distributions, I argue that understanding their origin and properties helps in elucidating their socio-economic consequences. I then explore a model of an economy where firms interact through a {\em production network} in a way that causes them to be intrinsically prone to amplify fluctuations. Later on, I conduct an empirical survey of the statistical properties of firm growth rates and provide a framework to study their dynamics. I finally move onto models where non-trivial collective phenomena arise from imitation and memory effects at the level of the individual, highlighting the need of accounting for complexity in economic modelling
PIRES, Robson Celso. "Complex-Valued Steady-State Models as Applied to Power Flow Analysis and Power System State Estimation." reponame:Repositório Institucional da UNIFEI, 2018. http://repositorio.unifei.edu.br/xmlui/handle/123456789/1359.
Повний текст джерелаMade available in DSpace on 2018-06-15T13:12:49Z (GMT). No. of bitstreams: 1 tese_2018_pires_robson.pdf: 2114807 bytes, checksum: d730bc3798b4777ca67282b62e72c7e0 (MD5) Previous issue date: 2018-06
Nonlinear systems of equations in complex domain are frequently encountered in applied mathematics, e.g., power systems, signal processing, control theory, neural networks and biomedicine, to name a few. The solution of these problems often requires a first- or second-order approximation of these nonlinear functions to generate a new step or descent direction to meet the solution iteratively. However, such methods cannot be applied to real functions of complex variables because they are necessarily non-analytic in their argument, i.e., the Taylor series expansion in their argument alone does not exist. To overcome this problem, the nonlinear function is usually redefined as a function of the real and imaginary parts of its complex argument so that standard methods can be applied. Although not widely known, it is possible to build an expansion of these nonlinear functions in its original complex variables by noting that functions of complex variables can be analytic in their argument and its complex conjugate as a whole. This property lies in the fact that if a function is analytic in the space spanned by ℜ{} and ℑ{}in ℝ, it is also analytic in the space spanned by and * in ℂ. The main contribution of this work is the application of this methodology to a complex Taylor series expansions aiming algorithms commonly used for solving complex-valued nonlinear systems of equations emerged from power systems problems. In our proposal, a complex-valued power ow analysis (CV PFA) model solved by Newton-Raphson method is revisited and enhanced. Nonetheless, especially emphasis is addressed to Gauss-Newton method when derived in complex domain for solving power system state estimation (CV PSSE) problems, whichever they are applied in transmission or distribution systems. The factorization method of the complex Jacobian matrices emerged from CV PFA and CV PSSE approaches is the Three Angle Complex Rotation (TACR) algorithm that comes from the Givens Rotations algorithm in real domain. In this research one demonstrates that Wirtinger derivatives can lead to greater insights in the structure of both problems, i.e., CV PFA & CV PSSE. Moreover, it can often be exploited to mitigate computational overhead, storage cost and enhance the network's component modeling as FACTS devices, e.g., STATCOM, VSC-HVDC, besides easily handle PMU measurements and embedding new technologies towards smart grids. Finally, in order to add numerical robustness, a fourth-order Levenberg-Marquardt algorithm is employed to the CV PFA & CV PSSE approaches because of its nice bi-quadratic convergence property, instead of the well-known quadratic convergence property of the classical Newton-Raphson and Gauss-Newton algorithms. Recall that these latter algorithms are prone to collapse when the power system network is ill-conditioned, i.e., it is heavily loaded or presents branches with high R/X ratio. These results are partially presented in this thesis because they are still under study and development. But most of them will appear in forthcoming papers submitted to IEEE-PES Transactions on Power Systems and coming up Top Conferences.
LUO, LINGEN. "Power system vulnerability and performance: application from complexity scienze and complex network." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2538888.
Повний текст джерелаPeddersen, Jorgen Computer Science & Engineering Faculty of Engineering UNSW. "Run-time energy-driven optimisation of embedded systems: a complete solution." Publisher:University of New South Wales. Computer Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/43240.
Повний текст джерелаWenzel, Eric. "An exploration of processes of mutual recognition in organization development initiatives from the standpoint of a practising consultant." Thesis, University of Hertfordshire, 2012. http://hdl.handle.net/2299/7658.
Повний текст джерелаMcCubbin, Michael. "The political economy of mental health, power and interests within a complex system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0023/NQ33057.pdf.
Повний текст джерелаBaek, Seong Cheol. "Dynamical Analysis and Decentralized Control of Power Packet Network." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263664.
Повний текст джерелаPack, Maria Joyce. "Complex metal oxide materials : synthesis, structural characterisation and development of combined EXAFS and powder differaction analysis." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243098.
Повний текст джерелаLevy, Renato. "Optimization Techniques for Energy-Aware Memory Allocation in Embedded Systems." Diss., Computer Science, George Washington University, 2004. http://hdl.handle.net/1961/116.
Повний текст джерелаA common practice to save power and energy in embedded systems is to "put to sleep" or disable parts of the hardware. The memory system consumes a significant portion of the energy budget of the overall system, so it is a natural target for energy optimization techniques. The principle of software locality makes the memory subsystem an even better choice, since all memory blocks but the ones immediately required can be disabled at any given time. This opportunity is the motivation for developing energy optimization techniques to dynamically and selectively control the power state of the different parts of the memory system. This dissertation develops a set of algorithms and techniques that can be organized into a hardware/software co-development tool to help designers apply the selective powering of memory blocks to minimize energy consumption. In data driven embedded systems, most of the data memory is used either by global static variables or by dynamic variables. Although techniques already exist for energy-aware allocation of global static arrays under certain constraints, very little work has focused on dynamic variables, which are actually more important to event driven/data driven embedded systems than their static counterparts. This dissertation addresses this gap, and extends and consolidates previous allocation techniques in a unique framework. A formal model for memory energy optimization for dynamic and global static variables and efficient algorithms for energy aware allocation of variables to memory are presented. Dependencies between generic code and data are uncovered, and this information is exploited to fine-tune a system. A framework is presented for retrieving this profile information which is then used to design energy aware allocation algorithms for dynamic variables, including heuristics for segmentation and control of the memory heap. By working at the assembly code level, these techniques can be integrated into any compiler regardless of the source language. The proposed techniques were implemented and tested against data intensive benchmarks, and experimental results indicate significant savings of up to 50% in the memory system energy consumption.
Advisory Committee: Professor Bhagirath Narahari, Professor Hyoeong-Ah Choi (Chair), Professor Rahul Simha, Professor Shmuel Rotenstreich, Professor Can E. Korman, Dr. Yul Williams
Jun, Min Su. "Three Essays on Complex Contractual Networks of Farmers." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1470869524.
Повний текст джерелаZhao, Shuang. "FORWARD AND BACKWARD EXTENDED PRONY (FBEP) METHOD WITH APPLICATIONS TO POWER SYSTEM SMALL-SIGNAL STABILITY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1480948469362031.
Повний текст джерелаBecher, Dirk. "Electrohydrostatic actuation system – an (almost) complete system view." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71207.
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