Tesis: "Linear discriminant analysis"

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Skinner, Evelina. "Linear Discriminant Analysis with Repeated Measurements." Thesis, Linköpings universitet, Matematisk statistik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162777.

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The classification of observations based on repeated measurements performed on the same subject over a given period of time or under different conditions is a common procedure in many disciplines such as medicine, psychology and environmental studies. In this thesis repeated measurements follow the Growth Curve model and are classified using linear discriminant analysis. The aim of this thesis is both to examine the effect of missing data on classification accuracy and to examine the effect of additional data on classification robustness. The results indicate that an increasing amount of missing data leads to a progressive decline in classification accuracy. With regard to the effect of additional data on classification robustness the results show a less predictable effect which can only be characterised as a general tendency towards improved robustness.

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2

Ganeshanandam, S. "Variable selection in two-group discriminant analysis using the linear discriminant function." Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379265.

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3

Kim, Jiae. "Nonlinear Generalizations of Linear Discriminant Analysis: the Geometry of the Common Variance Space and Kernel Discriminant Analysis." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1607019187556971.

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4

Li, Yongping. "Linear discriminant analysis and its application to face identification." Thesis, University of Surrey, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326513.

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5

Calderini, Matias. "Linear Discriminant Analysis and Noise Correlations in Neuronal Activity." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39962.

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The effects of noise correlations on neuronal stimulus discrimination have been the subject of sustained debate. Both experimental and computational work suggest beneficial and detrimental contributions of noise correlations. The aim of this study is to develop an analytically tractable model of stimulus discrimination that reveals the conditions leading to improved or impaired performance from model parameters and levels of noise correlation. We begin with a mean firing rate integrator model as an approximation of underlying spiking activity in neuronal circuits. We consider two independent units receiving constant input and time fluctuating noise whose correlation across units can be tuned independently of firing rate. We implement a perceptron-like readout with Fisher Linear Discriminant Analysis (LDA). We exploit its closed form solution to find explicit expressions for discrimination error as a function of network parameters (leak, shared inputs, and noise gain) as well as the strength of noise correlation. First, we derive equations for discrimination error as a function of noise correlation. We find that four qualitatively different sets of results exist, based on the ratios of the difference of means and variance of the distributions of neural activity. From network parameters, we find the conditions for which an increase in noise correlation can lead to monotonic decrease or monotonic increase of error, as well as conditions for which error evolves non-monotonically as a function of correlations. These results provide a potential explanation for previously reported contradictory effects of noise correlation. Second, we expand on the dependency of the quantitative behaviour of the error curve on the tuning of specific subsets of network parameters. Particularly, when the noise gain of a pair of units is increased, the error rate as a function of noise correlation increases multiplicatively. However, when the noise gain of a single unit is increased, under certain conditions, the effect of noise can be beneficial to stimulus discrimination. In sum, we present a framework of analysis that explains a series of non-trivial properties of neuronal discrimination via a simple linear classifier. We show explicitly how different configurations of parameters can lead to drastically different conclusions on the impact of noise correlations. These effects shed light on abundant experimental and computational results reporting conflicting effects of noise correlations. The derived analyses rely on few assumptions and may therefore be applicable to a broad class of neural models whose activity can be approximated by a multivariate distribution.

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6

Nguyen, Hoang-Huy [Verfasser]. "Multi-Step Linear Discriminant Analysis and Its Applications / Hoang Huy Nguyen." Greifswald : Universitätsbibliothek Greifswald, 2013. http://d-nb.info/1030246793/34.

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7

Van, Deventer Petrus Jacobus Uys. "Outliers, influential observations and robust estimation in non-linear regression analysis and discriminant analysis." Doctoral thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/4363.

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8

Draper, John Daniel. "Simultaneous Adaptive Fractional Discriminant Analysis: Applications to the Face Recognition Problem." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1331096665.

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9

NAKAGAWA, Seiichi, Norihide KITAOKA, and Makoto SAKAI. "Linear Discriminant Analysis Using a Generalized Mean of Class Covariances and Its Application to Speech Recognition." Institute of Electronics, Information and Communication Engineers, 2008. http://hdl.handle.net/2237/14967.

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10

Hennon, Christopher C. "Investigating Probabilistic Forecasting of Tropical Cyclogenesis Over the North Atlantic Using Linear and Non-Linear Classifiers." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1047237423.

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11

Tekinay, Cagri. "Classification Of Remotely Sensed Data By Using 2d Local Discriminant Bases." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610782/index.pdf.

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In this thesis, 2D Local Discriminant Bases (LDB) algorithm is used to 2D search structure to classify remotely sensed data. 2D Linear Discriminant Analysis (LDA) method is converted into an M-ary classifier by combining majority voting principle and linear distance parameters. The feature extraction algorithm extracts the relevant features by removing the irrelevant ones and/or combining the ones which do not represent supplemental information on their own. The algorithm is implemented on a remotely sensed airborne data set from Tippecanoe County, Indiana to evaluate its performance. The spectral and spatial-frequency features are extracted from the multispectral data and used for classifying vegetative species like corn, soybeans, red clover, wheat and oat in the data set.

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12

Khosla, Nitin, and n/a. "Dimensionality Reduction Using Factor Analysis." Griffith University. School of Engineering, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20061010.151217.

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In many pattern recognition applications, a large number of features are extracted in order to ensure an accurate classification of unknown classes. One way to solve the problems of high dimensions is to first reduce the dimensionality of the data to a manageable size, keeping as much of the original information as possible and then feed the reduced-dimensional data into a pattern recognition system. In this situation, dimensionality reduction process becomes the pre-processing stage of the pattern recognition system. In addition to this, probablility density estimation, with fewer variables is a simpler approach for dimensionality reduction. Dimensionality reduction is useful in speech recognition, data compression, visualization and exploratory data analysis. Some of the techniques which can be used for dimensionality reduction are; Factor Analysis (FA), Principal Component Analysis(PCA), and Linear Discriminant Analysis(LDA). Factor Analysis can be considered as an extension of Principal Component Analysis. The EM (expectation maximization) algorithm is ideally suited to problems of this sort, in that it produces maximum-likelihood (ML) estimates of parameters when there is a many-to-one mapping from an underlying distribution to the distribution governing the observation, conditioned upon the obervations. The maximization step then provides a new estimate of the parameters. This research work compares the techniques; Factor Analysis (Expectation-Maximization algorithm based), Principal Component Analysis and Linear Discriminant Analysis for dimensionality reduction and investigates Local Factor Analysis (EM algorithm based) and Local Principal Component Analysis using Vector Quantization.

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13

Khosla, Nitin. "Dimensionality Reduction Using Factor Analysis." Thesis, Griffith University, 2006. http://hdl.handle.net/10072/366058.

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In many pattern recognition applications, a large number of features are extracted in order to ensure an accurate classification of unknown classes. One way to solve the problems of high dimensions is to first reduce the dimensionality of the data to a manageable size, keeping as much of the original information as possible and then feed the reduced-dimensional data into a pattern recognition system. In this situation, dimensionality reduction process becomes the pre-processing stage of the pattern recognition system. In addition to this, probablility density estimation, with fewer variables is a simpler approach for dimensionality reduction. Dimensionality reduction is useful in speech recognition, data compression, visualization and exploratory data analysis. Some of the techniques which can be used for dimensionality reduction are; Factor Analysis (FA), Principal Component Analysis(PCA), and Linear Discriminant Analysis(LDA). Factor Analysis can be considered as an extension of Principal Component Analysis. The EM (expectation maximization) algorithm is ideally suited to problems of this sort, in that it produces maximum-likelihood (ML) estimates of parameters when there is a many-to-one mapping from an underlying distribution to the distribution governing the observation, conditioned upon the obervations. The maximization step then provides a new estimate of the parameters. This research work compares the techniques; Factor Analysis (Expectation-Maximization algorithm based), Principal Component Analysis and Linear Discriminant Analysis for dimensionality reduction and investigates Local Factor Analysis (EM algorithm based) and Local Principal Component Analysis using Vector Quantization. Thesis (Masters) Master of Philosophy (MPhil) School of Engineering Full Text

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14

Strong, Stephen. "Dimensionality Reduction for the Purposes of Automatic Pattern Classification." Thesis, Griffith University, 2013. http://hdl.handle.net/10072/367333.

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Pattern classification is a common technique used in a variety of applications. From simple tasks, such as password acceptance, to more complex tasks, such as identication by biometrics, speech recognition, and text recognition. As a result, a large number of pattern classification algorithms have emerged, allowing computers to perform these tasks. However, these techniques become less eective when excessive data on a given object is provided in comparison to the number of samples required to train. As a result, much research has been placed in nding ecient methods of reducing the dimensionality of the data while maintaining maximum classification accuracy. Dimensionality reduction aims to maximize the spread between samples of dierent classes, and mimimumize the spread between samples of the same class. A variety of methods aiming to do this have been reported in the literature. The most common methods of dimensionality reduction are Linear Discriminant Analysis and its variants. These typically focus on the spread of all the data, without regard to how spread out sections of the data already are. Few methods disregard the spread of data that is already spread out, but these are not so commonly accepted. While the classication accuracy is often better using these techniques, the computational time is often a large obstacle. This thesis will investigate several methods of dimensionality reduction, and then discuss algorithms to improve upon the existing algorithms. These algorithms utilize techniques that can be implemented on any hardware, making them suitable for any form of hardware. Thesis (Masters) Master of Philosophy (MPhil) School of Microelectronic Engineering Science, Environment, Engineering and Technology Full Text

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15

Azarmehr, Ramin. "Real-time Embedded Age and Gender Classification in Unconstrained Video." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32463.

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Recently, automatic demographic classification has found its way into embedded applications such as targeted advertising in mobile devices, and in-car warning systems for elderly drivers. In this thesis, we present a complete framework for video-based gender classification and age estimation which can perform accurately on embedded systems in real-time and under unconstrained conditions. We propose a segmental dimensionality reduction technique utilizing Enhanced Discriminant Analysis (EDA) to minimize the memory and computational requirements, and enable the implementation of these classifiers for resource-limited embedded systems which otherwise is not achievable using existing resource-intensive approaches. On a multi-resolution feature vector we have achieved up to 99.5% compression ratio for training data storage, and a maximum performance of 20 frames per second on an embedded Android platform. Also, we introduce several novel improvements such as face alignment using the nose, and an illumination normalization method for unconstrained environments using bilateral filtering. These improvements could help to suppress the textural noise, normalize the skin color, and rectify the face localization errors. A non-linear Support Vector Machine (SVM) classifier along with a discriminative demography-based classification strategy is exploited to improve both accuracy and performance of classification. We have performed several cross-database evaluations on different controlled and uncontrolled databases to assess the generalization capability of the classifiers. Our experiments demonstrated competitive accuracies compared to the resource-demanding state-of-the-art approaches.

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16

Zaeri, Naser. "Computation and memory efficient face recognition using binarized eigenphases and component-based linear discriminant analysis for wide range applications." Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/844078/.

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Face recognition finds many important applications in many life sectors and in particular in commercial and law enforcement. This thesis presents two novel methods which make face recognition more practical. In the first method, we propose an attractive solution for efficient face recognition systems that utilize low memory devices. The new technique applies the principal component analysis to the binarized phase spectrum of the Fourier transform of the covariance matrix constructed from the MPEG-7 Fourier Feature Descriptor vectors of the face images. Most of the algorithms proposed for face recognition are computationally exhaustive and hence they can not be used on devices constrained with limited memory; hence our method may play an important role in this area. The second method presented in this thesis proposes a new approach for efficient face representation and recognition by finding the best location component-based linear discriminant analysis. In this regard, the face image is decomposed into a number of components of certain size. Then the proposed scheme finds the best representation of the face image in most efficient way, taking into consideration both the recognition rate and the processing time. Note that the effect of the variation in a face image, when it is taken as a whole, is reduced when it is divided into components. As a result the performance of the system is enhanced. This method should find applications in systems requiring very high recognition and verification rates. Further, we demonstrate a solution to the problem of face occlusion using this method. The experimental results show that both proposed methods enhance the performance of the face recognition system and achieve a substantial saving in the computation time when compared to other known methods. It will be shown that the two proposed methods are very attractive for a wide range of applications for face recognition.

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17

Padovani, Carlos Roberto [UNESP]. "Aplicativo computacional para obtenção de probabilidades a priori de classificação errônea em experimentos agronômicos." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/101872.

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Made available in DSpace on 2014-06-11T19:31:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-07-27Bitstream added on 2014-06-13T21:02:58Z : No. of bitstreams: 1 padovani_crp_dr_botfca.pdf: 793418 bytes, checksum: 8b62c9d520c0086c46554fb418856bb7 (MD5) Nas Ciências Agronômicas, encontram-se várias situações em que são observadas diversas variáveis respostas nas parcelas ou unidades experimentais. Nestas situações, um caso de interesse prático à experimentação agronômica é o que considera a construção de regiões de similaridade entre as parcelas para a discriminação entre os grupos experimentais e ou para a classificação de novas unidades experimentais em uma dessas regiões. Os métodos de classificação ou discriminação exigem, para sua utilização prática, uma quantidade considerável de retenção de informação da estrutura de variabilidade dos dados e, principalmente, alta fidedignidade e competência nas alocações de novos indivíduos nos grupos, mostradas nas distribuições corretas destes indivíduos. Existem vários procedimentos para medir o grau de decisão correta (acurácia) das informações fornecidas pelos métodos classificatórios. Praticamente, a totalidade deles utilizam a probabilidade de classificação errônea como o indicador de qualidade, sendo alguns destes freqüentistas (probabilidade estimada pela freqüência relativa de ocorrências - métodos não paramétricos) e outros baseados nas funções densidade de probabilidade das populações (métodos paramétricos). A principal diferença entre esses procedimentos é a conceituação dada ao cálculo da probabilidade de classificação errônea. Pretende-se, no presente estudo, apresentar alguns procedimentos para estimar estas probabilidades, desenvolver um software para a obtenção das estimativas considerando a distância generalizada de Mahalanobis como o procedimento relativo à da função densidade de probabilidade para populações com distribuição multinormal . Este software será de acesso livre e de fácil manuseio para pesquisadores de áreas aplicadas, completado com o manual do usuário e com um exemplo de aplicação envolvendo divergência genética de girassol. In the Agronomical Sciences, mainly in studies involving biomass production and rational use of energy, there are several situations in which several variable answers in the parts or experimental units are observed. In these situations, a case of practical interest to the agronomical experimentation is that one which considers the construction of similarity regions among parts and or the classification of new experimental units. The classification methods demand, for their utilization, a considerable quantity for utilization of their information retention of data and, mostly, high fidelity and competence in the new individual allocations. There are several procedures to measure accuracy degree of the information supplied by the discrimination method. Practically all of them use the miss-classification probability (erroneous classification) like the quality indicator. The main difference among these evaluation methods is the characterization of the miss-classification probability. Therefore, the aim is to present some estimate procedures of the missclassification probabilities involving repetition frequency and distribution methods and to develop a software to obtain their estimate, which is accessible and easy handling for researchers of applied areas, complementing the study with user's manual and examples in the rational energy application and biomass energy.

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18

Wilgenbus, Erich Feodor. "The file fragment classification problem : a combined neural network and linear programming discriminant model approach / Erich Feodor Wilgenbus." Thesis, North-West University, 2013. http://hdl.handle.net/10394/10215.

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The increased use of digital media to store legal, as well as illegal data, has created the need for specialized tools that can monitor, control and even recover this data. An important task in computer forensics and security is to identify the true le type to which a computer le or computer le fragment belongs. File type identi cation is traditionally done by means of metadata, such as le extensions and le header and footer signatures. As a result, traditional metadata-based le object type identi cation techniques work well in cases where the required metadata is available and unaltered. However, traditional approaches are not reliable when the integrity of metadata is not guaranteed or metadata is unavailable. As an alternative, any pattern in the content of a le object can be used to determine the associated le type. This is called content-based le object type identi cation. Supervised learning techniques can be used to infer a le object type classi er by exploiting some unique pattern that underlies a le type's common le structure. This study builds on existing literature regarding the use of supervised learning techniques for content-based le object type identi cation, and explores the combined use of multilayer perceptron neural network classi ers and linear programming-based discriminant classi ers as a solution to the multiple class le fragment type identi cation problem. The purpose of this study was to investigate and compare the use of a single multilayer perceptron neural network classi er, a single linear programming-based discriminant classi- er and a combined ensemble of these classi ers in the eld of le type identi cation. The ability of each individual classi er and the ensemble of these classi ers to accurately predict the le type to which a le fragment belongs were tested empirically. The study found that both a multilayer perceptron neural network and a linear programming- based discriminant classi er (used in a round robin) seemed to perform well in solving the multiple class le fragment type identi cation problem. The results of combining multilayer perceptron neural network classi ers and linear programming-based discriminant classi ers in an ensemble were not better than those of the single optimized classi ers. MSc (Computer Science), North-West University, Potchefstroom Campus, 2013

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19

Almeida, Larissa Medeiros de. "Avaliação da gravidade da malária utilizando técnicas de extração de características e redes neurais artificiais." Universidade Federal do Amazonas, 2015. http://tede.ufam.edu.br/handle/tede/4093.

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Submitted by Kamila Costa (kamilavasconceloscosta@gmail.com) on 2015-06-15T21:53:52Z No. of bitstreams: 1 Dissertação-Larissa M de Almeida.pdf: 5516102 bytes, checksum: e49d2bccd21168f811140c6accd54e8f (MD5) Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-16T15:05:39Z (GMT) No. of bitstreams: 1 Dissertação-Larissa M de Almeida.pdf: 5516102 bytes, checksum: e49d2bccd21168f811140c6accd54e8f (MD5) Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-16T15:07:25Z (GMT) No. of bitstreams: 1 Dissertação-Larissa M de Almeida.pdf: 5516102 bytes, checksum: e49d2bccd21168f811140c6accd54e8f (MD5) Made available in DSpace on 2015-06-16T15:07:25Z (GMT). No. of bitstreams: 1 Dissertação-Larissa M de Almeida.pdf: 5516102 bytes, checksum: e49d2bccd21168f811140c6accd54e8f (MD5) Previous issue date: 2015-04-17 Não Informada About half the world's population lives in malaria risk areas. Moreover, given the globalization of travel, these diseases that were once considered exotic and mostly tropical are increasingly found in hospital emergency rooms around the world. And often when it comes to experience in tropical diseases, expert opinion most of the time is not available or not accessible in a timely manner. The task of an accurate and efficient diagnosis of malaria, essential in medical practice, can become complex. And the complexity of this process increases as patients have non-specific symptoms with a large amount of data and inaccurate information involved. In this approach, Uzoka and colleagues (2011a), from clinical information of 30 Nigerian patients with confirmed malaria, used the Analytic Hierarchy Process method (AHP) and Fuzzy methodology to conduct the evaluation of the severity of malaria. The results obtained were compared with the diagnosis of medical experts. This paper develops a new methodology to evaluate the severity of malaria and compare with the techniques used by Uzoka and colleagues (2011a). For this purpose the data set used is the same of that study. The technique used is the Artificial Neural Networks (ANN). Are evaluated three architectures with different numbers of neurons in the hidden layer, two training methodologies (leave-one-out and 10-fold cross-validation) and three stopping criteria, namely: the root mean square error, early stop and regularization. In the first phase, we use the full database. Subsequently, the feature extraction methods are used: in the second stage, the Principal Component Analysis (PCA) and in the third stage, the Linear Discriminant Analysis (LDA). The best result obtained in the three phases, it was with the full database, using the criterion of regularization associated with the leave-one-out method, of 83.3%. And the best result obtained in (Uzoka, Osuji and Obot, 2011) was with the fuzzy network which revealed 80% accuracy Cerca de metade da população mundial vive em áreas de risco da malária. Além disso, dada a globalização das viagens, essas doenças que antes eram consideradas exóticas e principalmente tropicais são cada vez mais encontradas em salas de emergência de hospitais no mundo todo. E frequentemente quando se trata de experiência em doenças tropicais, a opinião de especialistas na maioria das vezes está indisponível ou não acessível em tempo hábil. A tarefa de chegar a um diagnóstico da malária preciso e eficaz, fundamental na prática médica, pode tornar-se complexa. E a complexidade desse processo aumenta à medida que os pacientes apresentam sintomas não específicos com uma grande quantidade de dados e informação imprecisa envolvida. Nesse sentido, Uzoka e colaboradores (2011a), a partir de informações clínicas de 30 pacientes nigerianos com diagnóstico confirmado de malária, utilizaram a metodologia Analytic Hierarchy Process (AHP) e metodologia Fuzzy para realizar a avaliação da gravidade da malária. Os resultados obtidos foram comparados com o diagnóstico de médicos especialistas. Esta dissertação desenvolve uma nova metodologia para avaliação da gravidade da malária e a compara com as técnicas utilizadas por Uzoka e colaboradores (2011a). Para tal o conjunto de dados utilizados é o mesmo do referido estudo. A técnica utilizada é a de Redes Neurais Artificiais (RNA). São avaliadas três arquiteturas com diferentes números de neurônios na camada escondida, duas metodologias de treinamento (leave-one-out e 10-fold cross-validation) e três critérios de parada, a saber: o erro médio quadrático, parada antecipada e regularização. Na primeira fase, é utilizado o banco de dados completo. Posteriormente, são utilizados os métodos de extração de características: na segunda fase, a Análise dos Componentes Principais (do inglês, Principal Component Analysis - PCA) e na terceira fase, a Análise Discriminante Linear (do inglês, Linear Discriminant Analysis – LDA). O melhor resultado obtido nas três fases, foi com o banco de dados completo, utilizando o critério de regularização, associado ao leave-one-out, de 83.3%. Já o melhor resultado obtido em (Uzoka, Osuji e Obot, 2011) foi com a rede fuzzy onde obteve 80% de acurácia.

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20

Umunoza, Gasana Emelyne. "Misclassification Probabilities through Edgeworth-type Expansion for the Distribution of the Maximum Likelihood based Discriminant Function." Licentiate thesis, Linköpings universitet, Tillämpad matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-175873.

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This thesis covers misclassification probabilities via an Edgeworth-type expansion of the maximum likelihood based discriminant function. When deriving misclassification errors, first the expectation and variance in the population are assumed to be known where the variance is the same across populations and thereafter we consider the case where those parameters are unknown. Cumulants of the discriminant function for discriminating between two multivariate normal populations are derived. Approximate probabilities of the misclassification errors are established via an Edgeworth-type expansion using a standard normal distribution.

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21

Shin, Hyejin. "Infinite dimensional discrimination and classification." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5832.

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Modern data collection methods are now frequently returning observations that should be viewed as the result of digitized recording or sampling from stochastic processes rather than vectors of finite length. In spite of great demands, only a few classification methodologies for such data have been suggested and supporting theory is quite limited. The focus of this dissertation is on discrimination and classification in this infinite dimensional setting. The methodology and theory we develop are based on the abstract canonical correlation concept of Eubank and Hsing (2005), and motivated by the fact that Fisher's discriminant analysis method is intimately tied to canonical correlation analysis. Specifically, we have developed a theoretical framework for discrimination and classification of sample paths from stochastic processes through use of the Loeve-Parzen isomorphism that connects a second order process to the reproducing kernel Hilbert space generated by its covariance kernel. This approach provides a seamless transition between the finite and infinite dimensional settings and lends itself well to computation via smoothing and regularization. In addition, we have developed a new computational procedure and illustrated it with simulated data and Canadian weather data.

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22

Padovani, Carlos Roberto Pereira 1975. "Aplicativo computacional para obtenção de probabilidades a priori de classificação errônea em experimentos agronômicos /." Botucatu : [s.n.], 2007. http://hdl.handle.net/11449/101872.

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Orientador: Flávio Ferrari Aragon Banca: Adriano Wagner Ballarin Banca: Luís Fernando Nicolosi Bravin Banca: Rui Vieira de Moraes Banca: Sandra Fiorelli de Almeida P. Simeão Resumo: Nas Ciências Agronômicas, encontram-se várias situações em que são observadas diversas variáveis respostas nas parcelas ou unidades experimentais. Nestas situações, um caso de interesse prático à experimentação agronômica é o que considera a construção de regiões de similaridade entre as parcelas para a discriminação entre os grupos experimentais e ou para a classificação de novas unidades experimentais em uma dessas regiões. Os métodos de classificação ou discriminação exigem, para sua utilização prática, uma quantidade considerável de retenção de informação da estrutura de variabilidade dos dados e, principalmente, alta fidedignidade e competência nas alocações de novos indivíduos nos grupos, mostradas nas distribuições corretas destes indivíduos. Existem vários procedimentos para medir o grau de decisão correta (acurácia) das informações fornecidas pelos métodos classificatórios. Praticamente, a totalidade deles utilizam a probabilidade de classificação errônea como o indicador de qualidade, sendo alguns destes freqüentistas (probabilidade estimada pela freqüência relativa de ocorrências - métodos não paramétricos) e outros baseados nas funções densidade de probabilidade das populações (métodos paramétricos). A principal diferença entre esses procedimentos é a conceituação dada ao cálculo da probabilidade de classificação errônea. Pretende-se, no presente estudo, apresentar alguns procedimentos para estimar estas probabilidades, desenvolver um software para a obtenção das estimativas considerando a distância generalizada de Mahalanobis como o procedimento relativo à da função densidade de probabilidade para populações com distribuição multinormal . Este software será de acesso livre e de fácil manuseio para pesquisadores de áreas aplicadas, completado com o manual do usuário e com um exemplo de aplicação envolvendo divergência genética de girassol. Abstract: In the Agronomical Sciences, mainly in studies involving biomass production and rational use of energy, there are several situations in which several variable answers in the parts or experimental units are observed. In these situations, a case of practical interest to the agronomical experimentation is that one which considers the construction of similarity regions among parts and or the classification of new experimental units. The classification methods demand, for their utilization, a considerable quantity for utilization of their information retention of data and, mostly, high fidelity and competence in the new individual allocations. There are several procedures to measure accuracy degree of the information supplied by the discrimination method. Practically all of them use the miss-classification probability (erroneous classification) like the quality indicator. The main difference among these evaluation methods is the characterization of the miss-classification probability. Therefore, the aim is to present some estimate procedures of the missclassification probabilities involving repetition frequency and distribution methods and to develop a software to obtain their estimate, which is accessible and easy handling for researchers of applied areas, complementing the study with user's manual and examples in the rational energy application and biomass energy. Doutor

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23

Arpaci, Erdogan. "Analysis Of Sinusoidal And Helical Buckling Of Drill String In Horizontal Wells Using Finite Element Method." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611003/index.pdf.

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The number of horizontal wells is increasing rapidly in all over the world with the growth of new technological developments. During horizontal well drilling, much more complex problems occur when compared with vertical well drilling, such as decrease in load transfer to the bit, tubular failure, tubular fatigue and tubular lock-up. This makes selection of appropriate tubular and making the right drill string design more important. As the total compression load on the horizontal section increases, the behavior of the tubular changes from straight to sinusoidal buckling, and if the total compression load continues to increase the behavior of the tubular changes to helical buckling. Determination of critical buckling loads with finite element method (FEM) in horizontal wells is the main objective of this study. Initially, a computer program (ANSYS) that uses FEM is employed to simulate different tubular and well conditions. Four different pipe sizes, four different wellbore sizes and three different torque values are used to model the cases. Critical buckling load values corresponding to significant variables are collected from these simulated cases. The results are classified into different buckling modes according to the applied weight on bit values and the main properties of the simulated model, such as modulus of elasticity, moment of inertia of tubular cross section, weight per unit length of tubular and radial clearance between the wellbore and the tubular. Then, the boundary equations between the buckling modes are obtained. The equations developed in this thesis by simulating the cases for the specific tubular sizes are used to make a comparison between the critical buckling load values from the models in the literature and this work. It is observed that the results of this work fit with literature models as the tubular size increases. The influence of torque on critical buckling load values is investigated. It is observed that torque has a slight effect on critical buckling load values. Also the applicability of ANSYS for buckling problems was revealed by comparing the ANSYS results with the literature models&amp #8217 results and the experimental study in the literature.

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24

Mauk, Rachel Grant. "Prediction of Intensity Change Subsequent to Concentric Eyewall Events." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469037273.

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25

Milanez, Karla Danielle Tavares de Melo. "Classificação de óleos vegetais comestíveis usando imagens digitais e técnicas de reconhecimento de padrões." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/7157.

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Made available in DSpace on 2015-05-14T13:21:42Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3270377 bytes, checksum: f7faeeb5a1fdf2284d994edc54a6a265 (MD5) Previous issue date: 2013-08-26 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES This work presents a simple and non-expensive based on digital image and pattern recognition techniques for the classification of edible vegetable oils with respect to the type (soybean, canola, sunflower and corn) and the conservation state (expired and non-expired period of validity). For this, images of the sample oils were obtained from a webcam, and then, they were decomposed into histograms containing the distribution of color levels allowed for a pixel. Three representations for the color of a pixel were used: red-green-blue (RGB), hue-saturation-intensity (HSI) and grayscale. Linear discriminant analysis (LDA) was employed in order to build classification models on the basis of a reduced subset of variables. For the purpose of variable selection, two techniques were utilized, namely the successive projections algorithm (SPA) and stepwise (SW) formulation. Models based on partial least squares-discriminant analysis and (PLS-DA) applied to full histograms (without variable selection) were also employed for the purpose of comparison. For the study evolving the classification with respect to oil type, LDA/SPA, LDA /SW and PLS-DA models achieved a correct classification rate (CCR) of 95%, 90% and 95%, respectively. For the identification of expired non-expired samples, LDA / SPA models were found to the best method for classifying sunflower, soybean and canola oils, achieving a TCC of 97%, 94% and 93%, respectively, while the model LDA/SW correctly classified 100% of corn oil samples. These results suggest that the proposed method is a promising alternative for inspection of authenticity and the conservation state of edible vegetable oils. As advantages, the method does not use reagents to carry out the analysis and laborious procedures for chemical characterization of the samples are not required Este trabalho apresenta um método simples e de baixo custo, baseado na utilização de imagens digitais e técnicas de reconhecimento de padrões, para a classificação de óleos vegetais comestíveis com relação ao tipo (soja, canola, girassol e milho) e ao estado de conservação (prazo de validade expirado e não expirado). Para isso, imagens das amostras de óleos vegetais foram obtidas a partir de uma webcam e, em seguida, as mesmas foram decompostas em histogramas contendo as distribuições dos níveis de cores permitidos a um pixel. Três modelos para a cor de um pixel foram utilizados: vermelho-verde-azul (RGB), matiz-saturação-intensidade (HSI) e tons de cinza. A análise discriminante linear (LDA) foi utilizada para o desenvolvimento de modelos de classificação com base em um subconjunto reduzido de variáveis. Para fins de seleção de variáveis, duas técnicas foram utilizadas: o algoritmo das projeções sucessivas (SPA) e o stepwise (SW). Modelos baseados na análise discriminante por mínimos quadrados parciais (PLS-DA) aplicados aos histogramas completos (sem seleção de variáveis) também foram utilizados com o propósito de comparação. No estudo envolvendo a classificação com respeito ao tipo, modelos LDA/SPA, LDA/SW e PLS-DA atingiram uma taxa de classificação correta (TCC) de 95%, 90% e 95%, respectivamente. Na identificação de amostras expiradas e não expiradas, o modelo LDA/SPA foi considerado o melhor método para a classificação das amostras de óleos de girassol, soja e canola, atingindo uma TCC de 97%, 94% e 93%, respectivamente, enquanto que o modelo LDA/SW classificou corretamente 100% das amostras de milho. Estes resultados sugerem que o método proposto é uma alternativa promissora para a inspeção de autenticidade e estado de conservação de óleos vegetais comestíveis. Como vantagem, a metodologia não utiliza reagentes, a análise é rápida e procedimentos laboriosos para a caracterização química das amostras não são necessários

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DUARTE, Daniel Duarte. "Classificação de lesões em mamografias por análise de componentes independentes, análise discriminante linear e máquina de vetor de suporte." Universidade Federal do Maranhão, 2008. http://tedebc.ufma.br:8080/jspui/handle/tede/1816.

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Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-08-14T18:15:08Z No. of bitstreams: 1 DanielCosta.pdf: 1087754 bytes, checksum: ada5f863f42efd8298fff788c37bded3 (MD5) Made available in DSpace on 2017-08-14T18:15:08Z (GMT). No. of bitstreams: 1 DanielCosta.pdf: 1087754 bytes, checksum: ada5f863f42efd8298fff788c37bded3 (MD5) Previous issue date: 2008-02-25 Female breast cancer is the major cause of death in western countries. Efforts in Computer Vision have been made in order to add improve the diagnostic accuracy by radiologists. In this work, we present a methodology that uses independent component analysis (ICA) along with support vector machine (SVM) and linear discriminant analysis (LDA) to distinguish between mass or non-mass and benign or malign tissues from mammograms. As a result, it was found that: LDA reaches 90,11% of accuracy to discriminante between mass or non-mass and 95,38% to discriminate between benign or malignant tissues in DDSM database and in mini-MIAS database we obtained 85% to discriminate between mass or non-mass and 92% of accuracy to discriminate between benign or malignant tissues; SVM reaches 99,55% of accuracy to discriminate between mass or non-mass and the same percentage to discriminate between benign or malignat tissues in DDSM database whereas, and in MIAS database it was obtained 98% to discriminate between mass or non-mass and 100% to discriminate between benign or malignant tissues. Câncer de mama feminino é o câncer que mais causa morte nos países ocidentais. Esforços em processamento de imagens foram feitos para melhorar a precisão dos diagnósticos por radiologistas. Neste trabalho, nós apresentamos uma metodologia que usa análise de componentes independentes (ICA) junto com análise discriminante linear (LDA) e máquina de vetor de suporte (SVM) para distinguir as imagens entre nódulos ou não-nódulos e os tecidos em benignos ou malignos. Como resultado, obteve-se com LDA 90,11% de acurácia na discriminação entre nódulo ou não-nódulo e 95,38% na discriminação de tecidos benignos ou malignos na base de dados DDSM. Na base de dados mini- MIAS, obteve-se 85% e 92% na discriminação entre nódulos ou não-nódulos e tecidos benignos ou malignos respectivamente. Com SVM, alcançou-se uma taxa de até 99,55% na discriminação de nódulos ou não-nódulos e a mesma porcentagem na discriminação entre tecidos benignos ou malignos na base de dados DDSM enquanto que na base de dados mini-MIAS, obteve-se 98% e até 100% na discriminação de nódulos ou não-nódulos e tecidos benignos ou malignos, respectivamente.

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27

Åman, Agnes. "Predicting consultation durations in a digital primary care setting." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231921.

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The aim of this thesis is to develop a method to predict consultation durations in a digital primary care setting and thereby create a tool for designing a more efficient scheduling system in primary care. The ultimate purpose of the work is to contribute to a reduction in waiting times in primary care. Even though no actual scheduling system was implemented, four machine learning models were implemented and compared to see if any of them had better performance. The input data used in this study was a combination of patient and doctor features. The patient features consisted of information extracted from digital symptom forms filled out by a patient before a video consultation with a doctor. These features were combined with doctor's speed, defined as the doctor's average consultation duration for his/her previous meetings. The output was defined as the length of the video consultation including administrative work made by the doctor before and after the meeting. One of the objectives of this thesis was to investigate whether the relationship between input and output was linear or non-linear. Also the problem was formulated both as a regression and a classification problem. The two problem formulations were compared in terms of achieved accuracy. The models chosen for this study was linear regression, linear discriminant analysis and the multi-layer perceptron implemented for both regression and classification. After performing a statistical t-test and a two-way ANOVA test it was concluded that no significant difference could be detected when comparing the models' performances. However, since linear regression is the least computationally heavy it was suggested for future usage until it is proved that any other model achieves better performance. Limitations such as too few models being tested and flaws in the data set were identified and further research is encouraged. Studies implementing an actual scheduling system using the methodology presented in the thesis is recommended as a topic for future research. Syftet med denna uppsats är att utvärdera olika verktyg för att prediktera längden på ett läkarbesök och därmed göra det möjligt att skapa en mer effektiv schemaläggning i primärvården och på så sätt minska väntetiden för patienterna. Även om inget faktiskt schemaläggningssystem har föreslagits i denna uppsats så har fyra maskininlärningsmodeller implementerats och jämförts. Syftet med detta var bland annat att se om det var möjligt att dra slutsatsen att någon av modellerna gav bättre resultat än de andra. Den indata som använts i denna studie har bestått dels av symptomdata insamlad från symptomformulär ifylld av patienten före ett videomöte med en digital vårdgivare. Denna data har kombinerats med läkarens genomsnittliga mötestid i hens tidigare genomförda möten. Utdatan har definierats som längden av ett videomöte samt den tid som läkaren har behövt för administrativt arbete före och efter själva mötet. Ett av målen med denna studie var att undersöka som sambandet mellan indata och utdata är linjärt eller icke-linjärt. Ett annat mål var att formulera problemet både som ett regressionsproblem och som ett klassifikationsproblem. Syftet med detta var att kunna jämföra och se vilken av problemformuleringarna som gav bäst resultat. De modeller som har implementerats i denna studie är linjär regression, linjär diskriminationsanalys (linear discriminant analysis) och neurala nätverk implementerade för både regression och klassifikation. Efter att ha genomfört ett statistiskt t-test och en två-vägs ANOVA-analys kunde slutsatsen dras att ingen av de fyra studerade modellerna presterade signifikant bättre än någon av de andra. Eftersom linjär regression är enklare och kräver mindre datorkapacitet än de andra modellerna så dras slutsatsen att linjär regression kan rekommenderas för framtida användning tills det har bevisats att någon annan modell ger bättre resultat. De begränsningar som har identifierats hos studien är bland annat att det bara var fyra modeller som implementerats samt att datan som använts har vissa brister. Framtida studier som inkluderar fler modeller och bättre data har därför föreslagits. Dessutom uppmuntras framtida studier där ett faktiskt schemaläggningssystem implementeras som använder den metodik som föreslås i denna studie.

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Elnady, Maged Elsaid. "On-shaft vibration measurement using a MEMS accelerometer for faults diagnosis in rotating machines." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/onshaft-vibration-measurement-using-a-mems-accelerometer-for-faults-diagnosis-in-rotating-machines(cf9b9848-972d-49ff-a6b0-97bef1ad0e93).html.

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The healthy condition of a rotating machine leads to safe and cheap operation of almost all industrial facilities and mechanical systems. To achieve such a goal, vibration-based condition monitoring has proved to be a well-accepted technique that detects incipient fault symptoms. The conventional way of On-Bearing Vibration Measurement (OBVM) captures symptoms of different faults, however, it requires a relatively expensive setup, an additional space for the auxiliary devices and cabling in addition to an experienced analyst. On-Shaft Vibration Measurement (OSVM) is an emerging method proposed to offer more reliable Faults Diagnosis (FD) tools with less number of sensors, minimal processing time and lower system and maintenance costs. The advancement in sensor and wireless communications technologies enables attaching a MEMS accelerometer with a miniaturised wireless data acquisition unit directly to the rotor without altering the machine dynamics. In this study, OSVM is analysed during constant speed and run-up operations of a test rig. The observations showed response modulation, hence, a Finite Element (FE) analysis has been carried out to help interpret the experimental observations. The FE analysis confirmed that the modulation is due to the rotary motion of the on-shaft sensor. A demodulation method has been developed to solve this problem. The FD capability of OSVM has been compared to that of OBVM using conventional analysis where the former provided more efficient diagnosis with less number of sensors. To incorporate more features, a method has been developed to diagnose faults based on Principal Component Analysis and Nearest Neighbour classifier. Furthermore, the method is enhanced using Linear Discriminant Analysis to do the diagnosis without the need for a classifier. Another faults diagnosis method has been developed that ensures the generalisation of extracted faults features from OSVM data of a specific machine to similar machines mounted on different foundations.

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Švábek, Hynek. "Nalezení a rozpoznání dominantních rysů obličeje." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-237180.

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This thesis deals with the increasingly developing field of biometric systems which is the identification of faces. The thesis deals with the possibilities of face localization in pictures and their normalization, which is necessary due to external influences and the influence of different scanning techniques. It describes various techniques of localization of dominant features of the face such as eyes, mouth or nose. Not least, it describes different approaches to the identification of faces. Furthermore a it deals with an implementation of the Dominant Face Features Recognition application, which demonstrates chosen methods for localization of the dominant features (Hough Transform for Circles, localization of mouth using the location of the eyes) and for identification of a face (Linear Discriminant Analysis, Kernel Discriminant Analysis). The last part of the thesis contains a summary of achieved results and a discussion.

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30

Salmon, Elizabeth. "DEVELOPMENT OF AN EEG BRAIN-MACHINE INTERFACE TO AID IN RECOVERY OF MOTOR FUNCTION AFTER NEUROLOGICAL INJURY." UKnowledge, 2013. http://uknowledge.uky.edu/cbme_etds/8.

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Impaired motor function following neurological injury may be overcome through therapies that induce neuroplastic changes in the brain. Therapeutic methods include repetitive exercises that promote use-dependent plasticity (UDP), the benefit of which may be increased by first administering peripheral nerve stimulation (PNS) to activate afferent fibers, resulting in increased cortical excitability. We speculate that PNS delivered only in response to attempted movement would induce timing-dependent plasticity (TDP), a mechanism essential to normal motor learning. Here we develop a brain-machine interface (BMI) to detect movement intent and effort in healthy volunteers (n=5) from their electroencephalogram (EEG). This could be used in the future to promote TDP by triggering PNS in response to a patient’s level of effort in a motor task. Linear classifiers were used to predict state (rest, sham, right, left) based on EEG variables in a handgrip task and to determine between three levels of force applied. Mean classification accuracy with out-of-sample data was 54% (23-73%) for tasks and 44% (21-65%) for force. There was a slight but significant correlation (p<0.001) between sample entropy and force exerted. The results indicate the feasibility of applying PNS in response to motor intent detected from the brain.

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Gul, Ahmet Bahtiyar. "Holistic Face Recognition By Dimension Reduction." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1056738/index.pdf.

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Face recognition is a popular research area where there are different approaches studied in the literature. In this thesis, a holistic Principal Component Analysis (PCA) based method, namely Eigenface method is studied in detail and three of the methods based on the Eigenface method are compared. These are the Bayesian PCA where Bayesian classifier is applied after dimension reduction with PCA, the Subspace Linear Discriminant Analysis (LDA) where LDA is applied after PCA and Eigenface where Nearest Mean Classifier applied after PCA. All the three methods are implemented on the Olivetti Research Laboratory (ORL) face database, the Face Recognition Technology (FERET) database and the CNN-TURK Speakers face database. The results are compared with respect to the effects of changes in illumination, pose and aging. Simulation results show that Subspace LDA and Bayesian PCA perform slightly well with respect to PCA under changes in pose however, even Subspace LDA and Bayesian PCA do not perform well under changes in illumination and aging although they perform better than PCA.

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32

Gao, Hui. "Extracting key features for analysis and recognition in computer vision." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1141770523.

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Gooch, Steven R. "A METHOD FOR NON-INVASIVE, AUTOMATED BEHAVIOR CLASSIFICATION IN MICE, USING PIEZOELECTRIC PRESSURE SENSORS." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/56.

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While all mammals sleep, the functions and implications of sleep are not well understood, and are a strong area of investigation in the research community. Mice are utilized in many sleep studies, with electroencephalography (EEG) signals widely used for data acquisition and analysis. However, since EEG electrodes must be surgically implanted in the mice, the method is high cost and time intensive. This work presents an extension of a previously researched high throughput, low cost, non-invasive method for mouse behavior detection and classification. A novel hierarchical classifier is presented that classifies behavior states including NREM and REM sleep, as well as active behavior states, using data acquired from a Signal Solutions (Lexington, KY) piezoelectric cage floor system. The NREM/REM classification system presented an 81% agreement with human EEG scorers, indicating a useful, high throughput alternative to the widely used EEG acquisition method.

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Kim, Seongsu. "A BAYESIAN EVIDENCE DEFINING SEARCH." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429789001.

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Vaizurs, Raja Sarath Chandra Prasad. "Atrial Fibrillation Signal Analysis." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3386.

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Atrial fibrillation (AF) is the most common type of cardiac arrhythmia encountered in clinical practice and is associated with an increased mortality and morbidity. Identification of the sources of AF has been a goal of researchers for over 20 years. Current treatment procedures such as Cardio version, Radio Frequency Ablation, and multiple drugs have reduced the incidence of AF. Nevertheless, the success rate of these treatments is only 35-40% of the AF patients as they have limited effect in maintaining the patient in normal sinus rhythm. The problem stems from the fact that there are no methods developed to analyze the electrical activity generated by the cardiac cells during AF and to detect the aberrant atrial tissue that triggers it. In clinical practice, the sources triggering AF are generally expected to be at one of the four pulmonary veins in the left atrium. Classifying the signals originated from four pulmonary veins in left atrium has been the mainstay of signal analysis in this thesis which ultimately leads to correctly locating the source triggering AF. Unlike many of the current researchers where they use ECG signals for AF signal analysis, we collect intra cardiac signals along with ECG signals for AF analysis. AF Signal collected from catheters placed inside the heart gives us a better understanding of AF characteristics compared to the ECG. . In recent years, mechanisms leading to AF induction have begun to be explored but the current state of research and diagnosis of AF is mainly about the inspection of 12 lead ECG, QRS subtraction methods, spectral analysis to find the fibrillation rate and limited to establishment of its presence or absence. The main goal of this thesis research is to develop methodology and algorithm for finding the source of AF. Pattern recognition techniques were used to classify the AF signals originated from the four pulmonary veins. The classification of AF signals recorded by a stationary intra-cardiac catheter was done based on dominant frequency, frequency distribution and normalized power. Principal Component Analysis was used to reduce the dimensionality and further, Linear Discriminant Analysis was used as a classification technique. An algorithm has been developed and tested during recorded periods of AF with promising results.

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Ribeiro, Lucas de Almeida. "Algoritmo evolutivo multi-objetivo em tabelas para seleção de variáveis em classificação multivariada." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tede/4405.

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Submitted by Luanna Matias (lua_matias@yahoo.com.br) on 2015-04-01T14:19:27Z No. of bitstreams: 2 Dissertação - Lucas de Almeida Ribeiro - 2014.pdf: 6237054 bytes, checksum: 085446421b01a7e7b9174daf3da9b192 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Approved for entry into archive by Luanna Matias (lua_matias@yahoo.com.br) on 2015-04-01T15:19:35Z (GMT) No. of bitstreams: 2 Dissertação - Lucas de Almeida Ribeiro - 2014.pdf: 6237054 bytes, checksum: 085446421b01a7e7b9174daf3da9b192 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Made available in DSpace on 2015-04-01T15:19:35Z (GMT). No. of bitstreams: 2 Dissertação - Lucas de Almeida Ribeiro - 2014.pdf: 6237054 bytes, checksum: 085446421b01a7e7b9174daf3da9b192 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-10-29 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES This work proposes the use of multi-objective evolutionary algorithm on tables (AEMT) for variable selection in classification problems, using linear discriminant analysis. The proposed algorithm aims to find minimal subsets of the original variables, robust classifiers that model without significant loss in classification ability. The results of the classifiers modeled by the solutions found by this algorithm are compared in this work to those found by mono-objective formulations (such as PLS, APS and own implementations of a Simple Genetic Algorithm) and multi-objective formulations (such as the simple genetic algorithm multi -objective - MULTI-GA - and the NSGA II). As a case study, the algorithm was applied in the selection of spectral variables for classification by linear discriminant analysis (LDA) of samples of biodiesel / diesel. The results showed that the evolutionary formulations are solutions with a smaller number of variables (on average) and a better error rate (average) and compared to the PLS APS. The formulation of the AEMT proposal with the fitness functions: medium risk classification, number of selected variables and number of correlated variables in the model, found solutions with a lower average errors found by the NSGA II and the MULTI-GA, and also a smaller number of variables compared to the multi-GA. Regarding the sensitivity to noise the solution found by AEMT was less sensitive than other formulations compared, showing that the AEMT is more robust classifiers. Finally shows the separation regions of classes, based on the dispersion of samples, depending on the selected one of the solutions AEMT, it is noted that it is possible to determine variables of regions split from the selected variables. Este trabalho propõe o uso do algoritmo evolutivo multi-objetivo em tabelas (AEMT) para a seleção de variáveis em problemas de classificação, por meio de análise discriminante linear. O algoritmo proposto busca encontrar subconjuntos mínimos, das variáveis originais, que modelem classificadores robustos, sem perda significativa na capacidade de classificação. Os resultados dos classificadores modelados pelas soluções encontradas por este algoritmo são comparadas, neste trabalho, às encontradas por formulações mono-objetivo (como o PLS, o APS e implementações próprias de um Algoritmo Genético Simples) e formulações multi-objetivos (como algoritmo genético multi-objetivo simples - MULTI-GA - e o NSGA II). Como estudo de caso, o algoritmo foi aplicado na seleção de variáveis espectrais, para a classificação por análise discriminante linear (LDA - Linear Discriminant Analysis), de amostras de biodiesel/diesel. Os resultados obtidos mostraram que as formulações evolutivas encontram soluções com um menor número de variáveis (em média) e uma melhor taxa de erros (média) se comparadas ao PLS e o APS. A formulação do AEMT proposta com as funções de aptidão: risco médio de classificação, número de variáveis selecionadas e quantidade de variáveis correlacionadas presentes no modelo, encontrou soluções com uma média de erros inferior as encontradas pelo NSGA II e pelo MULTI-GA, e também uma menor quantidade de variáveis se comparado ao MULTI-GA. Em relação à sensibilidade a ruídos a solução encontrada pelo AEMT se mostrou menos sensível que as outras formulações comparadas, mostrando assim que o AEMT encontra classificadores mais robustos. Por fim, são apresentadas as regiões de separação das classes, com base na dispersão das amostras, em função das variáveis selecionadas por uma das soluções do AEMT, nota-se que é possível determinar regiões de separação a partir das variáveis selecionadas.

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37

Zhang, Angang. "Some Advances in Classifying and Modeling Complex Data." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/77958.

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In statistical methodology of analyzing data, two of the most commonly used techniques are classification and regression modeling. As scientific technology progresses rapidly, complex data often occurs and requires novel classification and regression modeling methodologies according to the data structure. In this dissertation, I mainly focus on developing a few approaches for analyzing the data with complex structures. Classification problems commonly occur in many areas such as biomedical, marketing, sociology and image recognition. Among various classification methods, linear classifiers have been widely used because of computational advantages, ease of implementation and interpretation compared with non-linear classifiers. Specifically, linear discriminant analysis (LDA) is one of the most important methods in the family of linear classifiers. For high dimensional data with number of variables p larger than the number of observations n occurs more frequently, it calls for advanced classification techniques. In Chapter 2, I proposed a novel sparse LDA method which generalizes LDA through a regularized approach for the two-class classification problem. The proposed method can obtain an accurate classification accuracy with attractive computation, which is suitable for high dimensional data with p>n. In Chapter 3, I deal with the classification when the data complexity lies in the non-random missing responses in the training data set. Appropriate classification method needs to be developed accordingly. Specifically, I considered the "reject inference problem'' for the application of fraud detection for online business. For online business, to prevent fraud transactions, suspicious transactions are rejected with unknown fraud status, yielding a training data with selective missing response. A two-stage modeling approach using logistic regression is proposed to enhance the efficiency and accuracy of fraud detection. Besides the classification problem, data from designed experiments in scientific areas often have complex structures. Many experiments are conducted with multiple variance sources. To increase the accuracy of the statistical modeling, the model need to be able to accommodate more than one error terms. In Chapter 4, I propose a variance component mixed model for a nano material experiment data to address the between group, within group and within subject variance components into a single model. To adjust possible systematic error introduced during the experiment, adjustment terms can be added. Specifically a group adaptive forward and backward selection (GFoBa) procedure is designed to select the significant adjustment terms. Ph. D.

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38

Bayik, Tuba Makbule. "Automatic Target Recognition In Infrared Imagery." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605388/index.pdf.

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The task of automatically recognizing targets in IR imagery has a history of approximately 25 years of research and development. ATR is an application of pattern recognition and scene analysis in the field of defense industry and it is still one of the challenging problems. This thesis may be viewed as an exploratory study of ATR problem with encouraging recognition algorithms implemented in the area. The examined algorithms are among the solutions to the ATR problem, which are reported to have good performance in the literature. Throughout the study, PCA, subspace LDA, ICA, nearest mean classifier, K nearest neighbors classifier, nearest neighbor classifier, LVQ classifier are implemented and their performances are compared in the aspect of recognition rate. According to the simulation results, the system, which uses the ICA as the feature extractor and LVQ as the classifier, has the best performing results. The good performance of this system is due to the higher order statistics of the data and the success of LVQ in modifying the decision boundaries.

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39

Pacola, Edras Reily. "Uso da análise de discriminante linear em conjunto com a transformada wavelet discreta no reconhecimento de espículas." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1828.

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CAPES Pesquisadores têm concentrado esforços, nos últimos 20 anos, aplicando a transformada wavelet no processamento, filtragem, reconhecimento de padrões e na classificação de sinais biomédicos, especificamente em sinais de eletroencefalografia (EEG) contendo eventos característicos da epilepsia, as espículas. Várias famílias de wavelets-mães foram utilizadas, mas sem um consenso sobre qual wavelet-mãe é a mais adequada para essa finalidade. Os sinais utilizados apresentam uma gama muito grande de eventos e não possuem características padronizadas. A literatura relata sinais de EEG amostrados entre 100 a 600 Hz, com espículas variando de 20 a 200 ms. Nesse estudo foram utilizadas 98 wavelets. Os sinais de EEG foram amostrados de 200 a 1 kHz. Um neurologista marcou um conjunto de 494 espículas e um conjunto de 1500 eventos não-espícula. Esse estudo inicia avaliando a quantidade de decomposições wavelets necessárias para a detecção de espículas, seguido pela análise detalhada do uso combinado de wavelets-mães de uma mesma família e entre famílias. Na sequência é analisada a influência de descritores e o uso combinado na detecção de espículas. A análise dos resultados desses estudos indica que é mais adequado utilizar um conjunto de wavelets-mães, com vários níveis de decomposição e com vários descritores, ao invés de utilizar uma única wavelet-mãe ou um descritor específico para a detecção de espículas. A seleção desse conjunto de wavelets, de níveis de decomposição e de descritores permite obter níveis de detecção elevados conforme a carga computacional que se deseje ou a plataforma computacional disponível para a implementação. Como resultado, esse estudo atingiu níveis de desempenho entre 0,9936 a 0,9999, dependendo da carga computacional. Outras contribuições desse estudo referem-se à análise dos métodos de extensão de borda na detecção de espículas; e a análise da taxa de amostragem de sinais de EEG no desempenho do classificador de espículas, ambos com resultados significativos. São também apresentadas como contribuições: uma nova arquitetura de detecção de espículas, fazendo uso da análise de discriminante linear; e a apresentação de um novo descritor, energia centrada, baseado na resposta dos coeficientes das sub-bandas de decomposição da transformada wavelet, capaz de melhorar a discriminação de eventos espícula e não-espícula. Researchers have concentrated efforts in the past 20 years, by applying the wavelet transform in processing, filtering, pattern recognition and classification of biomedical signals, in particular signals of electroencephalogram (EEG) containing events characteristic of epilepsy, the spike. Several families of mother-wavelets were used, but there are no consensus about which mother-wavelet is the most adequate for this purpose. The signals used have a wide range of events. The literature reports EEG signals sampled from 100 to 600 Hz with spikes ranging from 20 to 200 ms. In this study we used 98 wavelets. The EEG signals were sampled from 200 Hz up to 1 kHz. A neurologist has scored a set of 494 spikes and a set 1500 non-spike events. This study starts evaluating the amount of wavelet decompositions required for the detection of spikes, followed by detailed analysis of the combined use of mother-wavelets of the same family and among families. Following is analyzed the influence of descriptors and the combined use of them in spike detection. The results of these studies indicate that it is more appropriate to use a set of mother-wavelets, with many levels of decomposition and with various descriptors, instead of using a single mother-wavelet or a specific descriptor for the detection of spikes. The selection of this set of wavelets, decomposition level and descriptors allows to obtain high levels of detection according to the computational load desired or computing platform available for implementation. This study reached performance levels between 0.9936 to 0.9999, depending on the computational load. Other contributions of this study refer to the analysis of the border extension methods for spike detection; and the influences of the EEG signal sampling rate in the classifier performance, each one with significant results. Also shown are: a new spike detection architecture by making use of linear discriminant analysis; and the presentation of a new descriptor, the centred energy, based on the response of the coefficients of decomposition levels of the wavelet transform, able to improve the discrimination of spike and non-spike events.

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40

Kartheek, arun sai ram chilla, and Chelluboina Kavya. "Investigating Metrics that are Good Predictors of Human Oracle Costs An Experiment." Thesis, Blekinge Tekniska Högskola, Institutionen för programvaruteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-14080.

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Context. Human oracle cost, the cost associated in estimating the correctness of the output for the given test inputs is manually evaluated by humans and this cost is significant and is a concern in the software test data generation field. This study has been designed in the context to assess metrics that might predict human oracle cost. Objectives. The major objective of this study is to address the human oracle cost, for this the study identifies the metrics that are good predictors of human oracle cost and can further help to solve the oracle problem. In this process, the identified suitable metrics from the literature are applied on the test input, to see if they can help in predicting the correctness of the output for the given test input. Methods. Initially a literature review was conducted to find some of the metrics that are relevant to the test data. Besides finding the aforementioned metrics, our literature review also tries to find out some possible code metrics that can be ap- plied on test data. Before conducting the actual experiment two pilot experiments were conducted. To accomplish our research objectives an experiment is conducted in the BTH university with master students as sample population. Further group interviews were conducted to check if the participants perceive any new metrics that might impact the correctness of the output. The data obtained from the experiment and the interviews is analyzed using linear regression model in SPSS suite. Further to analyze the accuracy vs metric data, linear discriminant model using SPSS pro- gram suite was used. Results.Our literature review resulted in 4 metrics that are suitable to our study. As our test input is HTML we took HTML depth, size, compression size, number of tags as our metrics. Also, from the group interviews another 4 metrics are drawn namely number of lines of code and number of <div>, anchor <a> and paragraph tags as each individual metric. The linear regression model which analyses time vs metric data, shows significant results, but with multicollinearity effecting the result, there was no variance among the considered metrics. So, the results of our study are proposed by adjusting the multicollinearity. Besides, the above analysis, linear discriminant model which analyses accuracy vs metric data was conducted to predict the metrics that influences accuracy. The results of our study show that metrics positively correlate with time and accuracy. Conclusions. From the time vs metric data, when multicollinearity is adjusted by applying step-wise regression reduction technique, the program size, compression size and <div> tag are influencing the time taken by sample population. From accuracy vs metrics data number of <div> tags and number of lines of code are influencing the accuracy of the sample population.

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41

Feng, Qianli. "Automatic American Sign Language Imitation Evaluator." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461233570.

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42

Einestam, Ragnar, and Karl Casserfelt. "PiEye in the Wild: Exploring Eye Contact Detection for Small Inexpensive Hardware." Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20696.

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Ögonkontakt-sensorer skapar möjligheten att tolka användarens uppmärksamhet, vilketkan användas av system på en mängd olika vis. Dessa inkluderar att skapa nya möjligheterför människa-dator-interaktion och mäta mönster i uppmärksamhet hos individer.I den här uppsatsen gör vi ett försök till att konstruera en ögonkontakt-sensor med hjälpav en Raspberry Pi, med målet att göra den praktisk i verkliga scenarion. För att fastställaatt den är praktisk satte vi upp ett antal kriterier baserat på tidigare användning avögonkontakt-sensorer. För att möta dessa kriterier valde vi att använda en maskininlärningsmetodför att träna en klassificerare med bilder för att lära systemet att upptäcka omen användare har ögonkontakt eller ej. Vårt mål var att undersöka hur god prestanda vikunde uppnå gällande precision, hastighet och avstånd. Efter att ha testat kombinationerav fyra olika metoder för feature extraction kunde vi fastslå att den bästa övergripandeprecisionen uppnåddes genom att använda LDA-komprimering på pixeldatan från varjebild, medan PCA-komprimering var bäst när input-bilderna liknande de från träningen.När vi undersökte systemets hastighet fann vi att nedskalning av bilder hade en stor effektpå hastigheten, men detta sänkte också både precision och maximalt avstånd. Vi lyckadesminska den negativa effekten som en minskad skala hos en bild hade på precisionen, mendet maximala avståndet som sensorn fungerade på var fortfarande relativ till skalan och iförlängningen hastigheten. Eye contact detection sensors have the possibility of inferring user attention, which can beutilized by a system in a multitude of different ways, including supporting human-computerinteraction and measuring human attention patterns. In this thesis we attempt to builda versatile eye contact sensor using a Raspberry Pi that is suited for real world practicalusage. In order to ensure practicality, we constructed a set of criteria for the system basedon previous implementations. To meet these criteria, we opted to use an appearance-basedmachine learning method where we train a classifier with training images in order to inferif users look at the camera or not. Our aim was to investigate how well we could detecteye contacts on the Raspberry Pi in terms of accuracy, speed and range. After extensivetesting on combinations of four different feature extraction methods, we found that LinearDiscriminant Analysis compression of pixel data provided the best overall accuracy, butPrincipal Component Analysis compression performed the best when tested on imagesfrom the same dataset as the training data. When investigating the speed of the system,we found that down-scaling input images had a huge effect on the speed, but also loweredthe accuracy and range. While we managed to mitigate the effects the scale had on theaccuracy, the range of the system is still relative to the scale of input images and byextension speed.

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43

Onder, Murat. "Face Detection And Active Robot Vision." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605290/index.pdf.

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The main task in this thesis is to design a robot vision system with face detection and tracking capability. Hence there are two main works in the thesis: Firstly, the detection of the face on an image that is taken from the camera on the robot must be achieved. Hence this is a serious real time image processing task and time constraints are very important because of this reason. A processing rate of 1 frame/second is tried to be achieved and hence a fast face detection algorithm had to be used. The Eigenface method and the Subspace LDA (Linear Discriminant Analysis) method are implemented, tested and compared for face detection and Eigenface method proposed by Turk and Pentland is decided to be used. The images are first passed through a number of preprocessing algorithms to obtain better performance, like skin detection, histogram equalization etc. After this filtering process the face candidate regions are put through the face detection algorithm to understand whether there is a face or not in the image. Some modifications are applied to the eigenface algorithm to detect the faces better and faster. Secondly, the robot must move towards the face in the image. This task includes robot motion. The robot to be used for this purpose is a Pioneer 2-DX8 Plus, which is a product of ActivMedia Robotics Inc. and only the interfaces to move the robot have been implemented in the thesis software. The robot is to detect the faces at different distances and arrange its position according to the distance of the human to the robot. Hence a scaling mechanism must be used either in the training images, or in the input image taken from the camera. Because of timing constraint and low camera resolution, a limited number of scaling is applied in the face detection process. With this reason faces of people who are very far or very close to the robot will not be detected. A background independent face detection system is tried to be designed. However the resultant algorithm is slightly dependent to the background. There is no any other constraints in the system.

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44

Wang, Xuechuan, and n/a. "Feature Extraction and Dimensionality Reduction in Pattern Recognition and Their Application in Speech Recognition." Griffith University. School of Microelectronic Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030619.162803.

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Conventional pattern recognition systems have two components: feature analysis and pattern classification. Feature analysis is achieved in two steps: parameter extraction step and feature extraction step. In the parameter extraction step, information relevant for pattern classification is extracted from the input data in the form of parameter vector. In the feature extraction step, the parameter vector is transformed to a feature vector. Feature extraction can be conducted independently or jointly with either parameter extraction or classification. Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA) are the two popular independent feature extraction algorithms. Both of them extract features by projecting the parameter vectors into a new feature space through a linear transformation matrix. But they optimize the transformation matrix with different intentions. PCA optimizes the transformation matrix by finding the largest variations in the original feature space. LDA pursues the largest ratio of between-class variation and within-class variation when projecting the original feature space to a subspace. The drawback of independent feature extraction algorithms is that their optimization criteria are different from the classifiers minimum classification error criterion, which may cause inconsistency between feature extraction and the classification stages of a pattern recognizer and consequently, degrade the performance of classifiers. A direct way to overcome this problem is to conduct feature extraction and classification jointly with a consistent criterion. Minimum classification Error (MCE) training algorithm provides such an integrated framework. MCE algorithm was first proposed for optimizing classifiers. It is a type of discriminative learning algorithm but achieves minimum classification error directly. The flexibility of the framework of MCE algorithm makes it convenient to conduct feature extraction and classification jointly. Conventional feature extraction and pattern classification algorithms, LDA, PCA, MCE training algorithm, minimum distance classifier, likelihood classifier and Bayesian classifier, are linear algorithms. The advantage of linear algorithms is their simplicity and ability to reduce feature dimensionalities. However, they have the limitation that the decision boundaries generated are linear and have little computational flexibility. SVM is a recently developed integrated pattern classification algorithm with non-linear formulation. It is based on the idea that the classification that a.ords dot-products can be computed efficiently in higher dimensional feature spaces. The classes which are not linearly separable in the original parametric space can be linearly separated in the higher dimensional feature space. Because of this, SVM has the advantage that it can handle the classes with complex nonlinear decision boundaries. However, SVM is a highly integrated and closed pattern classification system. It is very difficult to adopt feature extraction into SVMs framework. Thus SVM is unable to conduct feature extraction tasks. This thesis investigates LDA and PCA for feature extraction and dimensionality reduction and proposes the application of MCE training algorithms for joint feature extraction and classification tasks. A generalized MCE (GMCE) training algorithm is proposed to mend the shortcomings of the MCE training algorithms in joint feature and classification tasks. SVM, as a non-linear pattern classification system is also investigated in this thesis. A reduced-dimensional SVM (RDSVM) is proposed to enable SVM to conduct feature extraction and classification jointly. All of the investigated and proposed algorithms are tested and compared firstly on a number of small databases, such as Deterding Vowels Database, Fishers IRIS database and Germans GLASS database. Then they are tested in a large-scale speech recognition experiment based on TIMIT database.

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45

Wang, Xuechuan. "Feature Extraction and Dimensionality Reduction in Pattern Recognition and Their Application in Speech Recognition." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/365680.

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Conventional pattern recognition systems have two components: feature analysis and pattern classification. Feature analysis is achieved in two steps: parameter extraction step and feature extraction step. In the parameter extraction step, information relevant for pattern classification is extracted from the input data in the form of parameter vector. In the feature extraction step, the parameter vector is transformed to a feature vector. Feature extraction can be conducted independently or jointly with either parameter extraction or classification. Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA) are the two popular independent feature extraction algorithms. Both of them extract features by projecting the parameter vectors into a new feature space through a linear transformation matrix. But they optimize the transformation matrix with different intentions. PCA optimizes the transformation matrix by finding the largest variations in the original feature space. LDA pursues the largest ratio of between-class variation and within-class variation when projecting the original feature space to a subspace. The drawback of independent feature extraction algorithms is that their optimization criteria are different from the classifier’s minimum classification error criterion, which may cause inconsistency between feature extraction and the classification stages of a pattern recognizer and consequently, degrade the performance of classifiers. A direct way to overcome this problem is to conduct feature extraction and classification jointly with a consistent criterion. Minimum classification Error (MCE) training algorithm provides such an integrated framework. MCE algorithm was first proposed for optimizing classifiers. It is a type of discriminative learning algorithm but achieves minimum classification error directly. The flexibility of the framework of MCE algorithm makes it convenient to conduct feature extraction and classification jointly. Conventional feature extraction and pattern classification algorithms, LDA, PCA, MCE training algorithm, minimum distance classifier, likelihood classifier and Bayesian classifier, are linear algorithms. The advantage of linear algorithms is their simplicity and ability to reduce feature dimensionalities. However, they have the limitation that the decision boundaries generated are linear and have little computational flexibility. SVM is a recently developed integrated pattern classification algorithm with non-linear formulation. It is based on the idea that the classification that a.ords dot-products can be computed efficiently in higher dimensional feature spaces. The classes which are not linearly separable in the original parametric space can be linearly separated in the higher dimensional feature space. Because of this, SVM has the advantage that it can handle the classes with complex nonlinear decision boundaries. However, SVM is a highly integrated and closed pattern classification system. It is very difficult to adopt feature extraction into SVM’s framework. Thus SVM is unable to conduct feature extraction tasks. This thesis investigates LDA and PCA for feature extraction and dimensionality reduction and proposes the application of MCE training algorithms for joint feature extraction and classification tasks. A generalized MCE (GMCE) training algorithm is proposed to mend the shortcomings of the MCE training algorithms in joint feature and classification tasks. SVM, as a non-linear pattern classification system is also investigated in this thesis. A reduced-dimensional SVM (RDSVM) is proposed to enable SVM to conduct feature extraction and classification jointly. All of the investigated and proposed algorithms are tested and compared firstly on a number of small databases, such as Deterding Vowels Database, Fisher’s IRIS database and German’s GLASS database. Then they are tested in a large-scale speech recognition experiment based on TIMIT database. Thesis (PhD Doctorate) Doctor of Philosophy (PhD) School of Microelectronic Engineering Full Text

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46

Sanchez, Merchante Luis Francisco. "Learning algorithms for sparse classification." Phd thesis, Université de Technologie de Compiègne, 2013. http://tel.archives-ouvertes.fr/tel-00868847.

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This thesis deals with the development of estimation algorithms with embedded feature selection the context of high dimensional data, in the supervised and unsupervised frameworks. The contributions of this work are materialized by two algorithms, GLOSS for the supervised domain and Mix-GLOSS for unsupervised counterpart. Both algorithms are based on the resolution of optimal scoring regression regularized with a quadratic formulation of the group-Lasso penalty which encourages the removal of uninformative features. The theoretical foundations that prove that a group-Lasso penalized optimal scoring regression can be used to solve a linear discriminant analysis bave been firstly developed in this work. The theory that adapts this technique to the unsupervised domain by means of the EM algorithm is not new, but it has never been clearly exposed for a sparsity-inducing penalty. This thesis solidly demonstrates that the utilization of group-Lasso penalized optimal scoring regression inside an EM algorithm is possible. Our algorithms have been tested with real and artificial high dimensional databases with impressive resuits from the point of view of the parsimony without compromising prediction performances.

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47

Janbain, Ali. "Utilisation d'algorithmes génétiques pour l'identification systématique de réseaux de gènes co-régulés." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT019/document.

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L’objectif de ce travail est de mettre au point une nouvelle approche automatique pour identifier les réseaux de gènes concourant à une même fonction biologique. Ceci permet une meilleure compréhension des phénomènes biologiques et notamment des processus impliqués dans les maladies telles que les cancers. Différentes stratégies ont été développées pour essayer de regrouper les gènes d’un organisme selon leurs relations fonctionnelles : génétique classique et génétique moléculaire. Ici, nous utilisons une propriété connue des réseaux de gènes fonctionnellement liés à savoir que ces gènes sont généralement co-régulés et donc co-exprimés. Cette co-régulation peut être mise en évidence par des méta-analyses de données de puces à ADN (micro-arrays) telles que Gemma ou COXPRESdb. Dans un travail précédent [Al Adhami et al., 2015], la topologie d’un réseau de co-expression de gènes a été caractérisé en utilisant deux paramètres de description des réseaux qui discriminent des groupes de gènes sélectionnés aléatoirement (modules aléatoires, RM) de groupes de gènes avec des liens fonctionnels connus (modules fonctionnels, FM), c’est-à-dire des gènes appartenant au même processus biologique GO. Dans le présent travail, nous avons cherché à généraliser cette approche et à proposer une méthode, appelée TopoFunc, pour améliorer l’annotation existante de la fonction génique. Nous avons d’abord testé différents descripteurs topologiques du réseau de co-expression pour sélectionner ceux qui identifient le mieux des modules fonctionnels. Puis, nous avons constitué une base de données rassemblant des modules fonctionnels et aléatoires, pour lesquels, sur la base des descripteurs sélectionnés, nous avons construit un modèle de discrimination LDA [Friedman et al., 2001] permettant, pour un sous-ensemble de gènes donné, de prédire son type (fonctionnel ou non). Basée sur la méthode de similarité de gènes travaillée par Wang et ses collègues [Wang et al., 2007], nous avons calculé un score de similarité fonctionnelle entre les gènes d’un module. Nous avons combiné ce score avec celui du modèle LDA dans une fonction de fitness implémenté dans un algorithme génétique (GA). À partir du processus biologique d’ontologie de gènes donné (GO-BP), AG visait à éliminer les gènes faiblement co-exprimés avec la plus grande clique de GO-BP et à ajouter des gènes «améliorant» la topologie et la fonctionnalité du module. Nous avons testé TopoFunc sur 193 GO-BP murins comprenant 50-100 gènes et avons montré que TopoFunc avait agrégé un certain nombre de nouveaux gènes avec le GO-BP initial tout en améliorant la topologie des modules et la similarité fonctionnelle. Ces études peuvent être menées sur plusieurs espèces (homme, souris, rat, et possiblement poulet et poisson zèbre) afin d’identifier des modules fonctionnels conservés au cours de l’évolution The aim of this work is to develop a new automatic approach to identify networks of genes involved in the same biological function. This allows a better understanding of the biological phenomena and in particular of the processes involved in diseases such as cancers. Various strategies have been developed to try to cluster genes of an organism according to their functional relationships : classical genetics and molecular genetics. Here we use a well-known property of functionally related genes mainly that these genes are generally co-regulated and therefore co-expressed. This co-regulation can be detected by microarray meta-analyzes databases such as Gemma or COXPRESdb. In a previous work [Al Adhami et al., 2015], the topology of a gene coexpression network was characterized using two description parameters of networks that discriminate randomly selected groups of genes (random modules, RM) from groups of genes with known functional relationship (functional modules, FM), e.g. genes that belong to the same GO Biological Process. We first tested different topological descriptors of the co-expression network to select those that best identify functional modules. Then, we built a database of functional and random modules for which, based on the selected descriptors, we constructed a discrimination model (LDA)[Friedman et al., 2001] allowing, for a given subset of genes, predict its type (functional or not). Based on the similarity method of genes worked by Wang and co-workers [Wang et al., 2007], we calculated a functional similarity score between the genes of a module. We combined this score with that of the LDA model in a fitness function implemented in a genetic algorithm (GA). Starting from a given Gene Ontology Biological Process (GO-BP), AG aimed to eliminate genes that were weakly coexpressed with the largest clique of the GO-BP and to add genes that "improved" the topology and functionality of the module. We tested TopoFunc on the 193 murine GO-BPs comprising 50-100 genes and showed that TopoFunc aggregated a number of novel genes to the initial GO-BP while improving module topology and functional similarity. These studies can be conducted on several species (humans, mice, rats, and possibly chicken and zebrafish) to identify functional modules preserved during evolution

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Macenauer, Oto. "Identifikace obličeje." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-237221.

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This document introduces the reader to area of face recognition. Miscellaneous methods are mentioned and categorized to be able to understand the process of face recognition. Main focus of this document is on issues of current face recognition and possibilities do solve these inconveniences in order to be able to massively spread face recognition. The second part of this work is focused on implementation of selected methods, which are Linear Discriminant Analysis and Principal Component Analysis. Those methods are compared to each other and results are given at the end of work.

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Zhong, Xiao. "A study of several statistical methods for classification with application to microbial source tracking." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0430104-155106/.

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Thesis (M.S.)--Worcester Polytechnic Institute. Keywords: classification; k-nearest-neighbor (k-n-n); neural networks; linear discriminant analysis (LDA); support vector machines; microbial source tracking (MST); quadratic discriminant analysis (QDA); logistic regression. Includes bibliographical references (p. 59-61).

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Novotný, Ondřej. "Adaptace systémů pro rozpoznání mluvčího." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2014. http://www.nusl.cz/ntk/nusl-236084.

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In this paper, we propose techniques for adaptation of speaker recognition systems. The aim of this work is to create adaptation for Probabilistic Linear Discriminant Analysis. Special attention is given to unsupervised adaptation. Our test shows appropriate clustering techniques for speaker estimation of the identity and estimation of the number of speakers in adaptation dataset. For the test, we are using NIST and Switchboard corpora.

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Tesis sobre el tema "Linear discriminant analysis"

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