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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.
671

Lean thinking and the factors necessary for its success

Pearce, Antony January 2014 (has links)
Lean management is becoming the standard for systematic productivity improvement, but the majority of implementations fail to sustain. Hence, the critical success factors for lean were the focus of this work. Literature review showed that the causality for lean success was not empirically developed beyond case study contextualisation. A multifaceted work was developed with contextualisation studies, survey of lean knowledge (758 responses), and a comprehensive case-study questionnaire (1253 responses from 44 countries). The statistical methods included exploratory factor analysis and path analysis by structural equation modelling (SEM). The first questionnaire revealed two different understandings of lean, and the second explored the underlying causality for lean success, including contingency for business size and product variety. Many contributions to the body of knowledge issued from this work. First of all, there was a methodological contribution, pioneering explorative structural modelling of full scope lean implementation. Second, SEMs of the lean knowledge-based view showed the profound positive effects of management knowledge on the primary factors for lean success. These factors were shown to be leadership and employee development. Third, the most beneficial lean methods were highlighted for specific scenarios. Fourth, the negligible and negative effects of a consultant-based approach to lean were uncovered. The results showed that the majority of consultants did not aid the long-term performance and sustainability of lean but significantly hindered it, except where masterful consultants acted as coaches. Fifth, a shortage of lean knowledge was observed in New Zealand; their participants averaged only half of what the USA�s did. Sixth, as culture has been emphasised in current literature, the present danger of overly focusing on it was discussed. Seventh was a conceptual contribution integrating lean and risk management, and a practical application with a risk analysis. This developed a risk matrix for the assessment and prioritisation of implementation components. Eighth, some adjustments to government lean strategies were proposed. And finally, the work integrated the findings in a tangible stage process model for implementation in SMEs. The dissemination of this knowledge has the potential to enhance productivity and commercial success of industries in New Zealand and abroad through successful lean implementations. Lean is not a weak methodology but it has been misunderstood and misapplied.
672

人口老化對於所得分配之影響―以臺灣二十三個縣市為例

俞哲民 Unknown Date (has links)
本研究欲觀察人口老化與所得分配之關係,檢視人口老化對於所得分配之影響,而文中主要分別從「內政部統計年報」、「家庭收支調查表」、「人力統計資源年報」以及各縣市統計要覽獲得各種解釋變數,建立出台灣1998年至2005年總計8年台灣各縣市之資料,並且以各縣市之吉尼係數為被解釋變數,採用最小平方法之方式藉此觀察台灣各縣市所得分配與人口老化之關係。 根據實證結果發現,人口老化與所得分配為顯著並且呈現正相關,亦即當人口老化更加嚴重時,將會導致較大的吉尼係數,造成所得不均之惡化。 其他解釋變數為顯著者分別有:平均每人可支配所得、平均每人可支配所得平方項、婦女勞動參與率以及各區域變數,且除了平均每人可支配所得平方項為負相關外,其餘皆與吉尼係數為正相關,其中所得方面之變數顯示出台灣中存在著Kuznets曲線;婦女勞動參與率的擴張則會導致所得分配更加惡化;中部、南部以及東部地區相對於北部區域來說其所得分配之狀況皆較不平均。而其他解釋變數如社會福利變數、教育變數以及工業變數所得之結果皆不顯著,顯示上述三個變數對台灣各縣市所得分配之影響在本研究中無法確定。 / This research discusses the relationship between aging population and income distribution, and examines how the aging population affects income distribution. The independent variables were acquired from the Statistical Yearbook of the Interior, The Survey of Family Income and Expenditure, the Statistical Yearbook of Labor Force and the Statistical Yearbook from each twenty-three counties and cities in Taiwan to construct a data set from 1998 to 2005. Using the ordinary least squares method and choosing the gini coefficient as a dependent variable to observe the relationship between income distribution and aging population. According to the result of the empirical study, we discover that the effect of aging population is significant and has a positive relationship with income distribution. Income inequality is worse when the aging population increases. Other significant independent variables are disposable income per person, the square of disposable income per person, female labor participation rate and the regional dummy variables. Besides the square of disposable income per person, all variables have a positive relationship with the gini coefficient. In addition, the variable of income shows that Kuznets curve appears in Taiwan. The expansion of the female labor participation will cause the income distribution to change into inequality. Also the north region has the worst income distribution in Taiwan. The results of the social welfare variable, the education variable and the industry variable are insignificant so that in this article we can not observe how the three variables effect the income distribution in Taiwan.
673

Precise Gravimetric Geoid Model for Iran Based on GRACE and SRTM Data and the Least-Squares Modification of Stokes’ Formula : with Some Geodynamic Interpretations

Kiamehr, Ramin January 2006 (has links)
Iran is one of the most complicated areas in the world from the view of rough topography, tectonic activity, large lateral density and geoidal height variations. The computation of a regional gravimetric geoid model with high accuracy in mountainous regions, especially with sparse data, is a difficult task that needs a special attention to obtain reliable results which can meet the needs of the today geodetic community. In this research different heterogeneous data has been used, which includes gravity anomalies, the high-resolution SRTM Digital Elevation Model (DEM), recently published GRACE Global Geopotential Models (GGMs), geological maps and GPS/levelling data. The above data has been optimally combined through the least-squares modification of Stokes formula with additive corrections. Regarding the data evaluation and refinement, the cross-validation technique has been used for detection of outliers. Also, several GGMs and DEMs are evaluated with GPS/levelling data. The impact of utilizing a high resolution SRTM DEM to improve the accuracy of the geoid model has been studied. Also, a density variation model has been established, and its effect on the accuracy of the geoid was investigated. Thereafter a new height datum for Iran was established based on the corrective surface idea. Finally, it was found that there is a significant correlation between the lateral geoid slope and the tectonic activities in Iran. We show that our hybrid gravimetric geoid model IRG04 agrees considerably better with GPS/levelling than any of the other recent local geoid models in the area. Its RMS fit with GPS/levelling is 27 cm and 3.8 ppm in the absolute and relative senses, respectively. Moreover, the relative accuracy of the IRG04 geoid model is at least 4 times better than any of the previously published global and regional geoid models in the area. Also, the RMS fit of the combined surface model (IRG04C) versus independent precise GPS/levelling is almost 4 times better compared to the original gravimetric geoid model (IRG04). These achievements clearly show the effect of the new gravity database and the SRTM data for the regional geoid determination in Iran based on the least-squares modification of Stokes’ formula. / <p>QC 20100906</p>
674

Méthode numérique d'estimation du mouvement des masses molles

Thouzé, Arsène 10 1900 (has links)
L’analyse biomécanique du mouvement humain en utilisant des systèmes optoélectroniques et des marqueurs cutanés considère les segments du corps comme des corps rigides. Cependant, le mouvement des tissus mous par rapport à l'os, c’est à dire les muscles et le tissu adipeux, provoque le déplacement des marqueurs. Ce déplacement est le fait de deux composantes, une composante propre correspondant au mouvement aléatoire de chaque marqueur et une composante à l’unisson provoquant le déplacement commun des marqueurs cutanés lié au mouvement des masses sous-jacentes. Si nombre d’études visent à minimiser ces déplacements, des simulations ont montré que le mouvement des masses molles réduit la dynamique articulaire. Cette observation est faite uniquement par la simulation, car il n'existe pas de méthodes capables de dissocier la cinématique des masses molles de celle de l’os. L’objectif principal de cette thèse consiste à développer une méthode numérique capable de distinguer ces deux cinématiques. Le premier objectif était d'évaluer une méthode d'optimisation locale pour estimer le mouvement des masses molles par rapport à l’humérus obtenu avec une tige intra-corticale vissée chez trois sujets. Les résultats montrent que l'optimisation locale sous-estime de 50% le déplacement des marqueurs et qu’elle conduit à un classement de marqueurs différents en fonction de leur déplacement. La limite de cette méthode vient du fait qu'elle ne tient pas compte de l’ensemble des composantes du mouvement des tissus mous, notamment la composante en unisson. Le second objectif était de développer une méthode numérique qui considère toutes les composantes du mouvement des tissus mous. Plus précisément, cette méthode devait fournir une cinématique similaire et une plus grande estimation du déplacement des marqueurs par rapport aux méthodes classiques et dissocier ces composantes. Le membre inférieur est modélisé avec une chaine cinématique de 10 degrés de liberté reconstruite par optimisation globale en utilisant seulement les marqueurs placés sur le pelvis et la face médiale du tibia. L’estimation de la cinématique sans considérer les marqueurs placés sur la cuisse et le mollet permet d'éviter l’influence de leur déplacement sur la reconstruction du modèle cinématique. Cette méthode testée sur 13 sujets lors de sauts a obtenu jusqu’à 2,1 fois plus de déplacement des marqueurs en fonction de la méthode considérée en assurant des cinématiques similaires. Une approche vectorielle a montré que le déplacement des marqueurs est surtout dû à la composante à l’unisson. Une approche matricielle associant l’optimisation locale à la chaine cinématique a montré que les masses molles se déplacent principalement autour de l'axe longitudinal et le long de l'axe antéro-postérieur de l'os. L'originalité de cette thèse est de dissocier numériquement la cinématique os de celle des masses molles et les composantes de ce mouvement. Les méthodes développées dans cette thèse augmentent les connaissances sur le mouvement des masses molles et permettent d’envisager l’étude de leur effet sur la dynamique articulaire. / Biomechanical analysis of human movement using optoelectronic system and skin markers considers body segments as rigid bodies. However the soft tissue motion relative to the bone, including muscles, fat mass, results in relative displacement of markers. This displacement is the results of two components, an own component which corresponds to a random motion of each marker and an in-unison component corresponding to the common movement of skin markers resulting from the movement of the underlying wobbling mass. While most studies aim to minimize these displacements, computer simulation models have shown that the movement of the soft tissue motion relative to the bones reduces the joint kinetics. This observation is only available using computer simulations because there are no methods able to distinguish the kinematics of wobbling mass of the bones kinematics. The main objective of this thesis is to develop a numerical method able to distinguish this different kinematics. The first aim of this thesis was to assess a local optimisation method for estimating the soft tissue motion using intra-cortical pins screwed into the humerus in three subjects. The results show that local optimisation underestimates of 50% the marker displacements. Also it leads to a different marker ranking in terms of displacement. The limit of local optimisation comes from the fact that it does not consider all the components of the soft tissue motion, especially the in-unison component. The second aim of this thesis was to develop a numerical method that accounts for all the component of the soft tissue motion. More specifically, this method should provide similar kinematics and estimate large marker displacement and distinguish the two components to conventional approaches. The lower limb is modeled using a 10 degree of freedom chain model reconstructed using global optimisation and the markers placed only on the pelvis and the medial face of the shank. The original estimate of joint kinematics without considering the markers placed on the thigh and on the calf avoids the influences of these markers displacement on the kinematic model reconstruction. This method was tested on 13 subjects who performed hopping trials and obtained up to 2.1 times of marker displacement depending the method considered ensuring similar joint-kinematics. A vector approach shown that marker displacements is more induce by the in-unison component. A matrix approach combining the local optimisation and the kinematic model shown that the wobbling mass moves around the longitudinal axis and along the antero-posterior axis of the bone. The originality of this thesis is to numerically distinguish the bone kinematics from the wobbling mass kinematics and the two components of the soft tissue motion. The methods developed in this thesis increases the knowledge on soft tissue motion and allow future studies to consider their movement in joint kinetics calculation.
675

Object Detection and Tracking Using Uncalibrated Cameras

Amara, Ashwini 14 May 2010 (has links)
This thesis considers the problem of tracking an object in world coordinates using measurements obtained from multiple uncalibrated cameras. A general approach to track the location of a target involves different phases including calibrating the camera, detecting the object's feature points over frames, tracking the object over frames and analyzing object's motion and behavior. The approach contains two stages. First, the problem of camera calibration using a calibration object is studied. This approach retrieves the camera parameters from the known locations of ground data in 3D and their corresponding image coordinates. The next important part of this work is to develop an automated system to estimate the trajectory of the object in 3D from image sequences. This is achieved by combining, adapting and integrating several state-of-the-art algorithms. Synthetic data based on a nearly constant velocity object motion model is used to evaluate the performance of camera calibration and state estimation algorithms.
676

Comparação de métodos de estimação para problemas com colinearidade e/ou alta dimensionalidade (p &gt; n ) / Comparison of estimation methods for problems with collinear and/or high dimensionality (p &gt; n)

Casagrande, Marcelo Henrique 29 April 2016 (has links)
Este trabalho apresenta um estudo comparativo do poder de predição de quatro métodos de regressão adequados para situações nas quais os dados, dispostos na matriz de planejamento, apresentam sérios problemas de multicolinearidade e/ou de alta dimensionalidade, em que o número de covariáveis é maior do que o número de observações. No presente trabalho, os métodos abordados são: regressão por componentes principais, regressão por mínimos quadrados parciais, regressão ridge e LASSO. O trabalho engloba simulações, em que o poder preditivo de cada uma das técnicas é avaliado para diferentes cenários definidos por número de covariáveis, tamanho de amostra e quantidade e intensidade de coeficientes (efeitos) significativos, destacando as principais diferenças entre os métodos e possibilitando a criação de um guia para que o usuário possa escolher qual metodologia usar com base em algum conhecimento prévio que o mesmo possa ter. Uma aplicação em dados reais (não simulados) também é abordada. / This paper presents a comparative study of the predictive power of four suitable regression methods for situations in which data, arranged in the planning matrix, are very poorly multicolinearity and / or highdimensionality, wherein the number of covariatesis greater the number of observations. In this study, the methods discussed are: principal component regression,partial least squares regression,ridge regression and LASSO. The work includes simulations, where in the predictive power of each of the techniques is evaluated for different scenarios defined by the number of covariates, sample size and quantity and intensity ratios (effects) significant, high lighting the main dffierences between the methods and allowing for the creating a guide for the user to choose which method to use based on some prior knowledge that it may have. An applicationon real data (not simulated) is also addressed.
677

[en] IDENTIFICATION OF MECHANICAL SYSTEMS PARAMETERS THROUGH INVERSE PROBLEM S RESOLUTION WITH BAYESIAN STATISTICAL INFERENCE / [pt] IDENTIFICAÇÃO DE PARÂMETROS EM SISTEMAS MECÂNICOS ATRAVÉS DA RESOLUÇÃO DO PROBLEMA INVERSO COM INFERÊNCIA ESTATÍSTICA BAYESIANA

MARIO GERMAN SANDOVAL 12 January 2015 (has links)
[pt] O problema de estimação pode ser entendido como um caso particular dos problemas inversos. Dadas observações da resposta de um sistema para certas causas, deseja-se estimar certas características do sistema. Essas características, em um sistema dinâmico, geralmente são representadas por parâmetros. Assim, para uma representação físico-matemática do sistema, dada uma excitação e observando a resposta, é possível obter uma estimação dos parâmetros. A estimação paramétrica é de grande importância e utilizada em diversas situações, desde experimentalistas, ao observar fenômenos no laboratório, até quem estuda o comportamento de setores sociais por amostras populacionais. A parte inicial desta dissertação apresenta uma breve introdução ao problema inverso do marco da estatística Bayesiana. Neste marco trata-se a estimação paramétrica como resultado da resolução de um problema inverso. Duas técnicas de estimação s ao deduzidas a partir da inferência estatística Bayesiana. A primeira delas, mínimos quadrados, coleta todos os dados e logo faz a estimação. A segunda, filtro de Kalman (e filtro de Kalman extendido), melhora o estado do conhecimento dos parâmetros a serem estimados a cada nova observação. Para a abordagem destas técnicas de estimação, de modo de poder compará-las, é apresentada a resolução analítica de um sistema harmônico de um e dois graus de liberdade. Por último, é apresentada uma modelagem de uma bancada experimental, em escala de laboratório, que emula uma coluna de perfura ção acoplada a um motor. Esta bancada foi desenvolvida para estudos de dinâmica torcional, na dissertação de mestrado de Bruno C. Cayres A., de modo que aqui só é de interesse a caracterização da mesma. As técnicas de estimação paramétrica são usadas de forma teórica, simulando os dados a partir de soluções analíticas para diferentes parâmetros da modelagem do motor e da coluna. Também usa-se medições feitas na bancada para estimar os parâmetros da modelagem, obtendo assim um conhecimento melhorado dos parâmetros envolvidos no sistema coluna-motor. / [en] The estimation problem can be understood as a particular case of an inverse problem. Given observations of the response of a system, due to certain causes, one wants to estimate certain characteristics of the problem. These features, in a dynamic system, are usually represented by parameters. Thus, for a mathematical representation of the physical system, given an excitation and given the observing response, it is possible to give an estimation of the parameters. The parameter estimation is of great importance and used in countless situations, such as experimental obseration of a phenomena in the laboratory or even by those who study the behaviors social sectors by population samples. The initial part of this dissertation presents a brief introduction to the inverse problem the framework of the Bayesian statistics. In this context, the parametric estimation is a result of the resolution of an inverse problem. Two estimation techniques are derived from the Bayesian statistical inference. The first of these, least squares, collects all the data and then makes the estimation. The second, Kalman filter (and extended filter Kalman), improves the state of knowledge of the parameters to be estimated, with each new observation. To address these estimation techniques, in order to be able to compare them, presents the analytical resolution of a harmonious system of one and two degrees of freedom. Finally, it is presented a model for an experimental setup, in laboratory scale, which emulates a drillstring coupled to a motor. This experimental setup was developed to study the dynamic torsional and by the author of the dissertation of Bruno C. Cayres A., the mode that is of interest here only the characterization of it. These techniques are used for parameter estimation in theoretical way, simulating data from the analytical solutions, for different parameters involved in the column-motor modeling. Also, we use measurements obtained from the experimental setup to estimate the parameters of the column-motor model. Thereby, we obtain an improved knowledge of the parameters involved in the column-motor.
678

[en] ALGORITHMS FOR PARTIAL LEAST SQUARES REGRESSION / [pt] ALGORITMOS PARA REGRESSÃO POR MÍNIMOS QUADRADOS PARCIAIS

RAUL PIERRE RENTERIA 08 January 2004 (has links)
[pt] Muitos problemas da área de aprendizagem automática tem por objetivo modelar a complexa relação existente num sisitema , entre variáveis de entrada X e de saída Y na ausência de um modelo teórico. A regressão por mínimos quadrados parciais PLS ( Partial Least Squares) constitui um método linear para resolução deste tipo de problema , voltado para o caso de um grande número de variáveis de entrada quando comparado com número de amostras. Nesta tese , apresentamos uma variante do algoritmo clássico PLS para o tratamento de grandes conjuntos de dados , mantendo um bom poder preditivo. Dentre os principais resultados destacamos um versão paralela PPLS (Parallel PLS ) exata para o caso de apenas um variável de saída e um versão rápida e aproximada DPLS (DIRECT PLS) para o caso de mais de uma variável de saída. Por outro lado ,apresentamos também variantes para o aumento da qualidade de predição graças à formulação não linear. São elas o LPLS ( Lifted PLS ), algoritmo para o caso de apenas uma variável de saída, baseado na teoria de funções de núcleo ( kernel functions ), uma formulação kernel para o DPLS e um algoritmo multi-kernel MKPLS capaz de uma modelagemmais compacta e maior poder preditivo, graças ao uso de vários núcleos na geração do modelo. / [en] The purpose of many problems in the machine learning field isto model the complex relationship in a system between the input X and output Y variables when no theoretical model is available. The Partial Least Squares (PLS)is one linear method for this kind of problem, for the case of many input variables when compared to the number of samples. In this thesis we present versions of the classical PLS algorithm designed for large data sets while keeping a good predictive power. Among the main results we highlight PPLS (Parallel PLS), a parallel version for the case of only one output variable, and DPLS ( Direct PLS), a fast and approximate version, for the case fo more than one output variable. On the other hand, we also present some variants of the regression algorithm that can enhance the predictive quality based on a non -linear formulation. We indroduce LPLS (Lifted PLS), for the case of only one dependent variable based on the theory of kernel functions, KDPLS, a non-linear formulation for DPLS, and MKPLS, a multi-kernel algorithm that can result in a more compact model and a better prediction quality, thankas to the use of several kernels for the model bulding.
679

Arborização urbana : estudo das praças do bairro centro de Teresina /

Moura, Ivanaldo Ribeiro de. January 2010 (has links)
Orientador: Sandra Elisa Contri Pitton / Banca: Ana Tereza Caceres Cortez / Banca: Roseana Correa Grilo / Resumo: A cidade é o lugar dos seres humanos. É nesse lugar que encontramos vivendo hoje a maioria das pessoas. É nas cidades que temos as maiores alterações na paisagem, e essas alterações geralmente comprometem a qualidade de vida. A supressão do verde das plantas é uma característica marcante nesse espaço. O presente trabalho procura pesquisar sobre a arborização urbana, dando um maior enfoque nas praças do bairro Centro de Teresina. Tem como objetivo identificar a diversidade vegetal arbórea, considerando a opinião de algumas pessoas sobre a importância da arborização das praças em sua vida. Esta pesquisa está dividida em três etapas distintas. A primeira etapa caracterizou-se pela pesquisa bibliográfica sobre o processo de formação das cidades, especialmente da capital do Piauí, e a importância da arborização para a qualidade de vida nos espaços urbanos. Na segunda etapa foi realizada uma pesquisa de campo para identificação e contagem das espécies vegetais encontradas nas praças do bairro Centro de Teresina. Na terceira fase da pesquisa foram aplicados questionários que serviram para obter a opinião de alguns freqüentadores das praças sobre a importância das árvores encontradas nesses logradouros públicos. Durante o trabalho foram discutidos muitos termos e conceitos utilizados para definir os espaços livres urbanos, o que mostra que ainda não existe um consenso entre os estudantes, pesquisadores e administradores públicos no que se refere à terminologia desses espaços. A pesquisa mostrou que as árvores fornecem diversos benefícios para os ambientes urbanos, estes geralmente muito alterados e degradados. Também é importante salientar sobre os diversos usos e funções das praças na malha urbana, onde o encontro foi destacado como o principal uso feito pelas pessoas que vivem nos espaços urbanos / Abstract: The city is the place of human beings. This is where we find most people living today. It is in cities that we have the largest changes in the landscape, and these changes often compromise the quality of life. The suppression of green plants is a distinguishing feature in this space. This current paper tries to research on urban trees, giving a greater focus on the squares of the district center of Teresina. Aims to identify woody plant diversity, considering the opinion of some people about the importance of afforestation of squares in your life. This research is divided into three distinct stages. The first stage was characterized by the literature on the process of formation of cities, especially in the capital of Piaui, and the importance of afforestation for the quality of life in urban spaces. In the second stage was conducted field research to identify and count plant species found in the streets of the district center of Teresina. In the view of some patrons of the squares on the importance of trees found in these public places. During the work were discussed many terms and concepts used to define urban spaces, which shows that there is still no consensus among students, researchers and public administrators regarding the terminology of these spaces. Research has shown that trees provide many benefits to urban environments, these usually much altered and degraded. It is also important to note about the various uses and functions of the squares on the urban environment, where the meeting was highlighted as the main use made by people living in urban areas / Mestre
680

Estudo de técnicas estatísticas aplicadas à determinação de parâmetros no método k0 de análise por ativação neutrônica / Improvement in statistical techniques applied to the determination of parameters in the k0 method of neutron activation analysis

Ribeiro, Rafael Vanhoz 21 September 2017 (has links)
O presente trabalho procurou aperfeiçoar um código criado para calcular os parâmetros k0 e Q0, denominado COVAR, adicionando um outro método para a determinação do fator k0 e aprimorar a análise de covariância existente, criando uma nova versão: COVAR v4.1. O presente trabalho também desenvolveu um novo método de cálculo para os parâmetros &alpha; e vários fatores k0 em um único ajuste de mínimos quadrados, por meio de uma metodologia inédita, utilizando matrizes de covariância e todas as incertezas parciais envolvidas. Para aplicação deste método, outro código foi desenvolvido, denominado AKFIT v2.1, no qual possui a capacidade de efetuar dois ajustes, linear e não-linear, na determinação de &alpha; e k0 para várias irradiações. Foi utilizado um conjunto de dados com irradiações realizadas nos anos de 2008 e 2010, pelo Laboratório de Metrologia Nuclear (LMN) e por meio do reator nuclear IEAR-1, do IPEN-CNEN/SP, correspondendo aos radionuclídeos 95Zr, 65Zn, 69mZn, 46Sc, 140La e 60Co, resultando em 21 conjuntos de dados a serem analisados para verificar o desempenho dos códigos criados. Para COVAR v 4.1, os resultados do cálculo alternativo para o fator k0 foram próximos dos valores obtidos pelo método original do programa e foram consistentes com a literatura. Para AKFIT v2.1, realizou-se ajustes com ambas irradiações simultâneas e separadas. Os modelos ajustados concordaram com a literatura. O valor de &alpha; foi de 0,0025(83), que está de acordo com resultados obtidos anteriormente pelo LMN. As correlações entre os parâmetros k0 se comportaram como esperado, com valores menores entre diferentes elementos e maiores entre elementos iguais com diferentes energias e usando o mesmo comparador. Pode-se concluir que os métodos propostos foram capazes de calcular os valores de k0, com AKFIT v2.1 sendo uma nova técnica no qual é possível determinar dois parâmetros, &alpha; e k0, ao mesmo tempo, de modo rápido e preciso. Espera-se que o código AKFIT possa ser aperfeiçoado, adicionando mais parâmetros, como Q0 e f, tornando-o uma ferramenta de ajuste completo para a determinação de todos os parâmetros essenciais do Método k0 de AAN. / The present work aims to improve a code for calculating k0 and Q0 parameters, called COVAR, adding another method of calculating k0 factor and improving the covariance analysis, creating a new version: COVAR v4.1. The present work also aims the development of a new method of calculating the alpha and several k0 parameters in a single least square fit, by means of a novel methodology, using covariance matrices and all partial uncertainties. For the calculations applying this new method, another code was developed, called AKFIT v2.1 which performs linear and non-linear fittings for the determination of alpha and k0 parameters for several irradiations in different periods. We used a database with irradiations in the years 2008 and 2010 performed at the IEAR-1 nuclear reactor of the IPEN-CNEN/SP, by the Nuclear Metrology Laboratory (LMN), corresponding to radionuclides 95Zr, 65Zn, 69mZn, 46Sc, 140La and 60Co and resulting in 21 data sets which were analyzed in order to verify the performance of COVAR4.1 and AKFIT2.1. For COVAR v4.1, the results with the alternative calculation of k0 factor were close to the already existing calculation and were consistent with the literature. For AKFIT v2.1 fittings were performed with both irradiations simultaneously and separately. The fitted models agreed with the literature. The &alpha; value was 0,0025(83), which agrees with previous results obtained by the LMN. The correlations between the parameters k0 behaved as expected, with smaller values between different elements and greater correlations between equal elements with different energies and using the same comparator measurement. It can be concluded that the proposed methods were able to calculate the values of k0, with AKFIT v2.1 being a new technique in which it is possible to determine two parameters, alpha and k0 at the same time, quickly and accurately. It is expected that AKFIT code can be improved by adding more parameters, such as Q0 and f, by making a complete fitting for the determination of all the main parameters for the k0 NAA method.

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