988 resultados para Identification parameters


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Os polimorfismos denominados Indels são variações de comprimento geradas por inserção ou deleção de um ou mais nucleotídeos em uma sequência de DNA. Estes marcadores genéticos vêm apresentando um grande potencial para fins forenses e populacionais por combinar características dos marcadores SNPs, tais como a capacidade de analisar fragmentos curtos (menores que 250pb) e baixas taxas de mutação, com a facilidade da genotipagem dos STR em uma única PCR, seguida de detecção dos fragmentos amplificados por eletroforese. Com o objetivo de avaliar a eficiência dos Indels em aplicações forenses e esclarecer os detalhes da formação de diferentes populações brasileiras através de dados genéticos, amostras populacionais de diferentes estados brasileiros foram genotipadas através de dois sistemas multiplex. O primeiro (indelplex-HID) foi otimizado para fins de Identificação Humana (HID) e inclui um grupo de 38 marcadores Indels selecionados por apresentarem altos valores de diversidade genética dentro das principais populações continentais. Já o segundo (46-AI-indels), foi selecionado para estudos de ancestralidade e é composto por um conjunto de 46 marcadores informativos de ancestralidade (AIMs). Nesse último caso, ao contrário do anterior, o sistema multiplex inclui marcadores com alta divergência nas frequências alélicas entre populações continentais. Na primeira etapa, o multiplex HID foi aplicado em uma amostra populacional do Rio de Janeiro e em uma amostra populacional dos índios Terena. Um banco de dados de frequências alélicas foi construído para essas duas amostras populacionais. Os valores das frequências alélicas foram utilizados nas comparações estatísticas e parâmetros de vínculos genéticos e forenses foram calculados. O Poder de Discriminação acumulado na população do Rio de Janeiro para os 38 loci testados foi de 0,9999999999999990 e na população dos índios Terena de 0,9999999999997, validando o uso desse sistema numa população heterogênea como a brasileira. A eficiência do indelplex-HID também mostrou-se elevada nas amostras de casos forenses comprometidas, apresentando melhor resultados que marcadores STR em termos de número de loci genotipados e de qualidade de amplificação. Na segunda etapa, o multiplex 46-AI-indels foi aplicado com objetivo de avaliar a ancestralidade em amostras de diferentes estados do Brasil por permitir a identificação de diferenças entre frequências alélicas de grupos populacionais separados geograficamente. A maioria das populações analisadas apresentou elevada herança européia. As populações do Rio de Janeiro, Pernambuco, Mato Grosso do Sul, Amazonas, Alagoas, Minas Gerais e São Paulo apresentaram cerca de 50% de ancestralidade européia, enquanto que nas populações que formam o sul do país e o Espírito Santo este percentual girou em torno de 70%. De uma maneira geral, as contribuições ameríndias e africanas variaram um pouco de acordo com a região. As amostras de Santa Isabel do Rio Negro e dos índios Terena (amostras indicadas como ameríndio-descendentes) de fato mostraram majoritariamente ancestralidade ameríndia (>70%). Os resultados obtidos indicaram que os dados gerados a partir da tipagem dos AIMs estão em estreita concordância com os registros históricos e com outros estudos genéticos acerca da formação da população brasileira e os loci do sistema HID evidenciaram que os são altamente informativos, constituindo uma ferramenta importante em estudos de identificação humana e de relações de parentesco.

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É descrita a modelagem, para controle, da dinâmica de uma plataforma semisubmersível com seis graus de liberdade. O modelo inclui os efeitos dos tanques de lastro como forças e momentos, assim como a dinâmica da plataforma. Os parâmetros do sistema foram obtidos das características da plataforma e de resultados experimentais obtidos com uma plataforma semisubmersível de dimensões reduzidas. O desenvolvimento de uma metodologia e de um software capazes de determinar o volume submerso e o centro de empuxo de uma estrutura com geometria complexa foram pontos determinantes nessa Dissertação, tendo em vista a complexidade do processo e as importâncias desses parâmetros para o desenvolvimento do modelo. A linearização do modelo permitiu a elaboração de uma estratégia de controle capaz de estabilizar a plataforma mesmo em condições iniciais distantes do equilíbrio. As equações que descrevem o movimento da plataforma nos graus de liberdade vertical, jogo e arfagem foram desenvolvidas. A realocação dos polos e um observador de estado foram utilizados com o objetivo de melhorar o controle do sistema.

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The modernization of the world made the speed, accuracy and reliability of all existing processes become increasingly necessary. For this evolution to occur every day, the evolution of the equipment was strategic, but not as much as needed. It is necessary for such equipment to ensure its function and, in case of failure, an early diagnosis to prevent loss. Therefore the evolution of maintainability and reliability in equipment is also paramount. Thus, the growth of forms of maintenance was driven by this scenario, forming maintenance philosophies. Among many, there is the RCM, which have its focus on the identification, parameters development and performance preview. One of those methodologies from this idea is the FMEA, process that has been studied and implemented this work, aiming the anticipation of failure modes and guidance for the use of a heat exchanger and a pump. This implementation has the aid of another process of RCM, the PHA, which was also shown and implemented, these results being used to start the FMEA process. The results show the activities with the highest chance of failure, presenting also the measures to be taken to avoid or minimize them. It is shown, in this paper, concern with the valves because they maintain control and system security, and its flaws related to accidents with possible danger to people and the whole system, emphasizing the priority of action

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The modernization of the world made the speed, accuracy and reliability of all existing processes become increasingly necessary. For this evolution to occur every day, the evolution of the equipment was strategic, but not as much as needed. It is necessary for such equipment to ensure its function and, in case of failure, an early diagnosis to prevent loss. Therefore the evolution of maintainability and reliability in equipment is also paramount. Thus, the growth of forms of maintenance was driven by this scenario, forming maintenance philosophies. Among many, there is the RCM, which have its focus on the identification, parameters development and performance preview. One of those methodologies from this idea is the FMEA, process that has been studied and implemented this work, aiming the anticipation of failure modes and guidance for the use of a heat exchanger and a pump. This implementation has the aid of another process of RCM, the PHA, which was also shown and implemented, these results being used to start the FMEA process. The results show the activities with the highest chance of failure, presenting also the measures to be taken to avoid or minimize them. It is shown, in this paper, concern with the valves because they maintain control and system security, and its flaws related to accidents with possible danger to people and the whole system, emphasizing the priority of action

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Stormwater is a potential and readily available alternative source for potable water in urban areas. However, its direct use is severely constrained by the presence of toxic pollutants, such as heavy metals (HMs). The presence of HMs in stormwater is of concern because of their chronic toxicity and persistent nature. In addition to human health impacts, metals can contribute to adverse ecosystem health impact on receiving waters. Therefore, the ability to predict the levels of HMs in stormwater is crucial for monitoring stormwater quality and for the design of effective treatment systems. Unfortunately, the current laboratory methods for determining HM concentrations are resource intensive and time consuming. In this paper, applications of multivariate data analysis techniques are presented to identify potential surrogate parameters which can be used to determine HM concentrations in stormwater. Accordingly, partial least squares was applied to identify a suite of physicochemical parameters which can serve as indicators of HMs. Datasets having varied characteristics, such as land use and particle size distribution of solids, were analyzed to validate the efficacy of the influencing parameters. Iron, manganese, total organic carbon, and inorganic carbon were identified as the predominant parameters that correlate with the HM concentrations. The practical extension of the study outcomes to urban stormwater management is also discussed.

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A new approach is proposed for obtaining a non-linear area-based equivalent model of power systems to express the inter-area oscillations using synchronised phasor measurements. The generators that remain coherent for inter-area disturbances over a wide range of operating conditions define the areas, and the reduced model is obtained by representing each area by an equivalent machine. The parameters of the reduced system are identified by processing the obtained measurements, and a non-linear Kalman estimator is then designed for the estimation of equivalent area angles and frequencies. The simulation of the approach on a two-area system shows substantial reduction of non-inter-area modes in the estimated angles. The proposed methods are also applied to a ten-machine system to illustrate the feasibility of the approach on larger and meshed networks.

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Traditionally, it is not easy to carry out tests to identify modal parameters from existing railway bridges because of the testing conditions and complicated nature of civil structures. A six year (2007-2012) research program was conducted to monitor a group of 25 railway bridges. One of the tasks was to devise guidelines for identifying their modal parameters. This paper presents the experience acquired from such identification. The modal analysis of four representative bridges of this group is reported, which include B5, B15, B20 and B58A, crossing the Carajás railway in northern Brazil using three different excitations sources: drop weight, free vibration after train passage, and ambient conditions. To extract the dynamic parameters from the recorded data, Stochastic Subspace Identification and Frequency Domain Decomposition methods were used. Finite-element models were constructed to facilitate the dynamic measurements. The results show good agreement between the measured and computed natural frequencies and mode shapes. The findings provide some guidelines on methods of excitation, record length of time, methods of modal analysis including the use of projected channel and harmonic detection, helping researchers and maintenance teams obtain good dynamic characteristics from measurement data.

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A method is presented for identification of parameters in unconfined aquifers from pumping tests, based on the optimisation of the objective function using the least squares approach. Four parameters are to be evaluated, namely: The hydraulic conductivity in the radial and the vertical directions, the storage coefficient and the specific yield. The sensitivity analysis technique is used for solving the optimisation problem. Besides eliminating the subjectivity involved in the graphical procedure, the method takes into account the field data at all time intervals without classifying them into small and large time intervals and does not use the approximation that the ratio of the storage coefficient to the specific yield tends to zero. Two illustrative examples are presented and it is found that the parameter estimates from the computational and graphical procedures differ fairly significantly.

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When a thin rectangular plate is restrained on the two long edges and free on the remaining edges, the equivalent stiffness of the restraining joints can be identified by the order of the natural frequencies obtained using the free response of the plate at a single location. This work presents a method to identify the equivalent stiffness of the restraining joints, being represented as simply supporting the plate but elastically restraining it in rotation. An integral transform is used to map the autospectrum of the free response from the frequency domain to the stiffness domain in order to identify the equivalent torsional stiffness of the restrained edges of the plate and also the order of natural frequencies. The kernel of the integral transform is built interpolating data from a finite element model of the plate. The method introduced in this paper can also be applied to plates or shells with different shapes and boundary conditions. © 2011 Elsevier Ltd. All rights reserved.

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This paper presents the results of a real bridge field experiment in which damage was applied artificially to a steel truss bridge. The aim of this paper is to identify the dynamic parameters of this bridge using conventional techniques and investigate the effect of various damage conditions on those parameters. In the field experiment, acceleration measurements were recorded at a number of locations on the bridge deck. To excite the bridge, a two-axle van was driven across the bridge at constant speed. Dynamic parameters, such as the bridge mode shape, natural frequency and damping constant, are identified from the acceleration signals using existing techniques such as the fast Fourier transform, logarithmic decrement and frequency domain decomposition. The variation of these parameters under the influence of artificially applied damage conditions is investigated in order to evaluate their sensitivity to the bridge damage.

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Clean and renewable energy generation and supply has drawn much attention worldwide in recent years, the proton exchange membrane (PEM) fuel cells and solar cells are among the most popular technologies. Accurately modeling the PEM fuel cells as well as solar cells is critical in their applications, and this involves the identification and optimization of model parameters. This is however challenging due to the highly nonlinear and complex nature of the models. In particular for PEM fuel cells, the model has to be optimized under different operation conditions, thus making the solution space extremely complex. In this paper, an improved and simplified teaching-learning based optimization algorithm (STLBO) is proposed to identify and optimize parameters for these two types of cell models. This is achieved by introducing an elite strategy to improve the quality of population and a local search is employed to further enhance the performance of the global best solution. To improve the diversity of the local search a chaotic map is also introduced. Compared with the basic TLBO, the structure of the proposed algorithm is much simplified and the searching ability is significantly enhanced. The performance of the proposed STLBO is firstly tested and verified on two low dimension decomposable problems and twelve large scale benchmark functions, then on the parameter identification of PEM fuel cell as well as solar cell models. Intensive experimental simulations show that the proposed STLBO exhibits excellent performance in terms of the accuracy and speed, in comparison with those reported in the literature.

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This paper presents the practical use of Prony Analysis to identify small signal oscillation mode parameters from simulated and actual phasor measurement unit (PMU) ringdown data. A well-known two-area four-machine power system was considered as a study case while the latest PMU ringdown data were collected from a double circuit 275 kV main interconnector on the Irish power system. The eigenvalue analysis and power spectral density were also conducted for the purpose of comparison. The capability of Prony Analysis to identify the mode parameters from three different types of simulated PMU ringdown data has been shown successfully. Furthermore, the results indicate that the Irish power system has dominant frequency modes at different frequencies. However, each mode has good system damping.