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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Compensation Methods for Demand Response

Wang, Zhaofeng 01 January 2015 (has links)
Recently, more and more disputations about how demand response should be compensated have arisen. Moreover, the court is about to rehear the Order 745. It probably will have significant impact on the whole working system used to be built for demand response before. Nowadays, some power companies and utilities think that they will endure profits leakage while demand response resources still are compensated. In this research, knowledge of demand response, local marginal price, Order 745 and other related concept will be explained in detail in case of misunderstanding. Associated with all these knowledge, a possible compensation method will be proposed. It combines many existing compensation methods. It mainly can be divided into three parts, i.e., high load period, off-peak period and low load period. The demand response resources will be compensated appropriately through these three periods. The compensation method endeavors to be just and reasonable.
2

Proposição de modelos de fluxo de potência polar intervalar mediante utilização de métodos de compensação

Medeiros, Bárbara da Silva 19 July 2018 (has links)
Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-10-16T13:11:39Z No. of bitstreams: 1 barbaradasilvamedeiros.pdf: 3659351 bytes, checksum: 5f3a83604095b292ba8f61cabaa96f53 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-10-16T14:35:57Z (GMT) No. of bitstreams: 1 barbaradasilvamedeiros.pdf: 3659351 bytes, checksum: 5f3a83604095b292ba8f61cabaa96f53 (MD5) / Made available in DSpace on 2018-10-16T14:35:58Z (GMT). No. of bitstreams: 1 barbaradasilvamedeiros.pdf: 3659351 bytes, checksum: 5f3a83604095b292ba8f61cabaa96f53 (MD5) Previous issue date: 2018-07-19 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta dissertação, duas novas estratégias são propostas para calcular o problema do fluxo de potência sujeito às incertezas nos parâmetros das linhas de transmissão e das cargas dos sistemas elétricos. No estudo de fluxo de potência tradicional, os parâmetros dos sistemas de potência são tratados como quantidades determinísticas. Entretanto, esses dados, como a impedância das linhas de transmissão e a potência aparente das cargas conectadas às barras, podem apresentar incertezas associadas à medição ou à variação ao longo do tempo. Técnicas baseadas em amostragem, como Monte Carlo, apresentam resultados excelentes, porém demandam elevado tempo de processamento computacional. Por isso, atualmente, técnicas soft-computing, que apresentam resultados confiáveis de maneira eficiente, sem necessitar de muitos recursos computacionais, têm sido pesquisadas. O objetivo deste trabalho é, neste sentido, adaptar metodologias existentes na literatura, que não são utilizadas, a princípio, para este fim, para a solução do fluxo de potência intervalar e avaliar se os resultados são confiáveis e eficientes. A adaptação é realizada considerando pequenas incertezas, como geralmente ocorre na realidade, resultando em métodos aproximados de análise de fluxo de potência intervalar. O primeiro método desenvolvido é baseado na técnica de montagem direta da matriz impedância de barras, sem recorrer à inversão da matriz admitância de barras. O segundo método é baseado no Teorema da Compensação, utilizado na análise de sensibilidade. O algoritmo é desenvolvido e testado em Matlab, considerando diferentes casos de incerteza, com os seguintes sistemastestes: brasileiro de 33 barras, IEEE de 57 barras e brasileiro de 107 barras. Os resultados são comparados com aqueles gerados pela simulação de Monte Carlo, a fim de validação. Em geral, os métodos apresentam desempenho satisfatório, pois resultados intervalares viáveis de tensão e fluxo de potência, assim como perdas nas linhas, são encontrados como esperado, sem a aplicação de técnicas existentes na literatura, como a matemática intervalar ou aritmética affine. / In this dissertation, two new strategies are proposed to calculate the problem of power flow subjected to uncertainties in the parameters of transmission lines and loads of electrical systems. In traditional power flow analisys, power system parameters are treated as deterministic quantities. However some data, such as the impedance of transmission lines and the apparent power of loads connected to buses, may present uncertainties associated with measurement or variation over time. Sampling techniques, such as Monte Carlo, present excellent results, but require a high processing time. Therefore, nowadays, soft-computing techniques, which present reliable results in an efficient manner, without the need of many computational resources, have been researched. In this sense, the objective of this work is to adapt existing methodologies in the literature, which are not used for this purpose, for the solution of interval power flow and to evaluate if the results are reliable and efficient. The adaptation is performed considering small uncertainties, as usually occurs in reality, resulting in approximate methods of interval power flow analysis. The first method developed is based on the technique of direct assembly of the bus impedance matrix, without resorting to the inversion of the bus admittance matrix. The second method is based on the Compensation Theorem, used in the sensitivity analysis. The algorithm is developed and tested in Matlab, considering different cases of uncertainty, with the following test systems: Brazilian 33-bus, IEEE 57-bus and Brazilian 107-bus. The results are compared with those generated by the Monte Carlo simulation for validation. In general, the methods present satisfactory performance, as viable intervals of voltage and power flow, as well as losses in the lines, are found as expected, without application of techniques existing in the literature, such as interval mathematics or arithmetic affine.
3

Zpracování MR obrazových dat při měření tkáňových kultur / MR image data processing in study of tissue cultures

Bidman, Petr January 2009 (has links)
Techniques based on principle of nuclear magnetic resonance (NMR) belong to the most modern methods for studying physical, chemical and biological properties of materials [1]. Their universality predestinates them for application in a wide range of scientific disciplines, e.g. in medicine to study properties of tissues. Advantages of techniques utilizing principle of NMR consist in their noninvasiveness and thoughtfulness to human health or studied material. In addition, no undesirable effects of magnetic force field have been so far proved by research. Objectives of this Diploma Thesis are evaluation of MR images of tissue cultures and determination of protons amount included in them. Theoretic part of the Thesis is devoted to the bases of NMR and provides basic overview of MR methods. The spin echo method (SE) is described in more details, including the process of assessment of technique’s parameters, e.g. general magnetization. Practical part of Diploma Thesis is focused on determination of integral of image intensity of clusters of early somatic embryos. Intensity integrals characterizing number of protons in growing cluster were calculated from MR images of spruce embryos contaminated by lead. The intensity of an image weighted by spin density is proportionate to the number of proton nuclei in the chosen slice. The Thesis describes further evaluation of relaxation time T2 from MR images weighted by spin density. Following part is dealing with determination of diffusion from MR images with application of compensation methods, three-measurement arrangement and presentation of obtained results. Images were processed by use of MATLAB and MAREVISI programs.
4

PMD - polarizační vidová disperze a vliv na přenos / PMD - polarization mode dispersion and its effects on data transport

Trávníček, Pavel January 2009 (has links)
My graduation thesis is concerned with the effect of polarization mode dispersion on transmitted signal by optical line. It describes external and internal causes of origination of polarization mode dispersion. On the basis of these effects there is a differential group delay (DGD). It is the time delay in meantime within individual modes. DGD results in a time extension of impulsion and limitation of maximum bit rate. This thesis contains localization methods of part of gossamer filament with increased value of PMD by POTDR method. This method is based on the principium of back dispersion and its modifications SOP a DOP. Very important chapter of this thesis is the measurement of the polarization mode dispersion. There are described methods of PMD measurement. It is the interferometric and polarimetric method and the method of state of polarization. The major part of this thesis is about the reduction of polarization mode dispersion effect. This part is divided into two parts. First part is about the methods of PMD effect reduction and the second one is about the PMD compensation. The discrepancy between these two parts is the reduction way of PMD effect on transmitted channel. The compensation use the compensation components inserted into the transmission path. By PMD reduction methods we can solve the problems from the view of changing of fibre or all cable. For better understanding of polarization mode dispersion effect there are simulated 4 optical lanes of various parameters. The simulation output is the eye diagram which provides the view at results of transmission lane. In the final part there is the evaluation of measured parameters of optical lanes simulated in a laboratory.

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