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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Aprendizado de estruturas de dependência entre fenótipos da síndrome metabólica em estudos genômicos / Structure learning of the metabolic syndrome phenotypes network in family genomic studies

Wilk, Lilian Skilnik 26 June 2017 (has links)
Introdução: O número de estudos relacionados à Síndrome Metabólica (SM) vem aumentando nos últimos anos, muitas vezes motivados pelo aumento do número de casos de sobrepeso/obesidade e diabetes Tipo II levando ao desenvolvimento de doenças cardiovasculares e, como consequência, infarto agudo do miocárdio e AVC, dentre outros desfechos desfavoráveis. A SM é uma doença multifatorial composta de cinco características, porém, para que um indivíduo seja diagnosticado com ela, possuir pelo menos três dessas características torna-se condição suficiente. Essas cinco características são: Obesidade visceral, caracterizada pelo aumento da circunferência da cintura, Glicemia de jejum elevada, Triglicérides aumentado, HDL-colesterol reduzido, Pressão Arterial aumentada. Objetivo: Estabelecer a rede de associações entre os fenótipos que compõem a Síndrome Metabólica através do aprendizado de estruturas de dependência, decompor a rede em componentes de correlação genética e ambiental e avaliar o efeito de ajustes por covariáveis e por variantes genéticas exclusivamente relacionadas à cada um dos fenótipos da rede. Material e Métodos: A amostra do estudo corresponderá a 79 famílias da cidade mineira de Baependi, composta por 1666 indivíduos. O aprendizado de estruturas de redes será feito por meio da Teoria de Grafos e Modelos de Equações Estruturais envolvendo o modelo linear misto poligênico para determinar as relações de dependência entre os fenótipos que compõem a Síndrome Metabólica / Introduction: The number of studies related to Metabolic Syndrome (MetS) has been increasing in the last years, encouraged by the increase on the overweight / obesity and Type II Diabetes cases, leading to the development of cardiovascular disease and, therefore, acute myocardial infarction and stroke, and others unfavorable outcomes. MetS is a multifactorial disease containing five characteristics, however, for an individual to be diagnosed with MetS, he/she may have at least three of them. These characteristics are: Truncal Obesity, characterized by increasing on the waist circumference, increasing on Fasting Blood Glucose, increasing on Triglycerides, decreasing on HDL cholesterol and increasing on Blood Pressure. Aims: Establish the best association network between MetS phenotypes through structured dependency learning between phenotypes considering genetic variants exclusively related to each phenotype. Materials and Methods: The study sample is composed of 79 families, 1666 individuals of a city in a rural area of Brazil, called Beapendi. Structured learning will use graph theory and Structural Equations Models to establish the dependency relations between MetS phenotypes
12

Uncovering Structure in High-Dimensions: Networks and Multi-task Learning Problems

Kolar, Mladen 01 July 2013 (has links)
Extracting knowledge and providing insights into complex mechanisms underlying noisy high-dimensional data sets is of utmost importance in many scientific domains. Statistical modeling has become ubiquitous in the analysis of high dimensional functional data in search of better understanding of cognition mechanisms, in the exploration of large-scale gene regulatory networks in hope of developing drugs for lethal diseases, and in prediction of volatility in stock market in hope of beating the market. Statistical analysis in these high-dimensional data sets is possible only if an estimation procedure exploits hidden structures underlying data. This thesis develops flexible estimation procedures with provable theoretical guarantees for uncovering unknown hidden structures underlying data generating process. Of particular interest are procedures that can be used on high dimensional data sets where the number of samples n is much smaller than the ambient dimension p. Learning in high-dimensions is difficult due to the curse of dimensionality, however, the special problem structure makes inference possible. Due to its importance for scientific discovery, we put emphasis on consistent structure recovery throughout the thesis. Particular focus is given to two important problems, semi-parametric estimation of networks and feature selection in multi-task learning.
13

Learning with Sparcity: Structures, Optimization and Applications

Chen, Xi 01 July 2013 (has links)
The development of modern information technology has enabled collecting data of unprecedented size and complexity. Examples include web text data, microarray & proteomics, and data from scientific domains (e.g., meteorology). To learn from these high dimensional and complex data, traditional machine learning techniques often suffer from the curse of dimensionality and unaffordable computational cost. However, learning from large-scale high-dimensional data promises big payoffs in text mining, gene analysis, and numerous other consequential tasks. Recently developed sparse learning techniques provide us a suite of tools for understanding and exploring high dimensional data from many areas in science and engineering. By exploring sparsity, we can always learn a parsimonious and compact model which is more interpretable and computationally tractable at application time. When it is known that the underlying model is indeed sparse, sparse learning methods can provide us a more consistent model and much improved prediction performance. However, the existing methods are still insufficient for modeling complex or dynamic structures of the data, such as those evidenced in pathways of genomic data, gene regulatory network, and synonyms in text data. This thesis develops structured sparse learning methods along with scalable optimization algorithms to explore and predict high dimensional data with complex structures. In particular, we address three aspects of structured sparse learning: 1. Efficient and scalable optimization methods with fast convergence guarantees for a wide spectrum of high-dimensional learning tasks, including single or multi-task structured regression, canonical correlation analysis as well as online sparse learning. 2. Learning dynamic structures of different types of undirected graphical models, e.g., conditional Gaussian or conditional forest graphical models. 3. Demonstrating the usefulness of the proposed methods in various applications, e.g., computational genomics and spatial-temporal climatological data. In addition, we also design specialized sparse learning methods for text mining applications, including ranking and latent semantic analysis. In the last part of the thesis, we also present the future direction of the high-dimensional structured sparse learning from both computational and statistical aspects.
14

Aprendizado de estruturas de dependência entre fenótipos da síndrome metabólica em estudos genômicos / Structure learning of the metabolic syndrome phenotypes network in family genomic studies

Lilian Skilnik Wilk 26 June 2017 (has links)
Introdução: O número de estudos relacionados à Síndrome Metabólica (SM) vem aumentando nos últimos anos, muitas vezes motivados pelo aumento do número de casos de sobrepeso/obesidade e diabetes Tipo II levando ao desenvolvimento de doenças cardiovasculares e, como consequência, infarto agudo do miocárdio e AVC, dentre outros desfechos desfavoráveis. A SM é uma doença multifatorial composta de cinco características, porém, para que um indivíduo seja diagnosticado com ela, possuir pelo menos três dessas características torna-se condição suficiente. Essas cinco características são: Obesidade visceral, caracterizada pelo aumento da circunferência da cintura, Glicemia de jejum elevada, Triglicérides aumentado, HDL-colesterol reduzido, Pressão Arterial aumentada. Objetivo: Estabelecer a rede de associações entre os fenótipos que compõem a Síndrome Metabólica através do aprendizado de estruturas de dependência, decompor a rede em componentes de correlação genética e ambiental e avaliar o efeito de ajustes por covariáveis e por variantes genéticas exclusivamente relacionadas à cada um dos fenótipos da rede. Material e Métodos: A amostra do estudo corresponderá a 79 famílias da cidade mineira de Baependi, composta por 1666 indivíduos. O aprendizado de estruturas de redes será feito por meio da Teoria de Grafos e Modelos de Equações Estruturais envolvendo o modelo linear misto poligênico para determinar as relações de dependência entre os fenótipos que compõem a Síndrome Metabólica / Introduction: The number of studies related to Metabolic Syndrome (MetS) has been increasing in the last years, encouraged by the increase on the overweight / obesity and Type II Diabetes cases, leading to the development of cardiovascular disease and, therefore, acute myocardial infarction and stroke, and others unfavorable outcomes. MetS is a multifactorial disease containing five characteristics, however, for an individual to be diagnosed with MetS, he/she may have at least three of them. These characteristics are: Truncal Obesity, characterized by increasing on the waist circumference, increasing on Fasting Blood Glucose, increasing on Triglycerides, decreasing on HDL cholesterol and increasing on Blood Pressure. Aims: Establish the best association network between MetS phenotypes through structured dependency learning between phenotypes considering genetic variants exclusively related to each phenotype. Materials and Methods: The study sample is composed of 79 families, 1666 individuals of a city in a rural area of Brazil, called Beapendi. Structured learning will use graph theory and Structural Equations Models to establish the dependency relations between MetS phenotypes
15

Exploiting non-redundant local patterns and probabilistic models for analyzing structured and semi-structured data

Wang, Chao 08 January 2008 (has links)
No description available.
16

[en] EVOCATIVE METHODOLOGY FOR CAUSAL MAPPING AND ITS PERSPECTIVE IN THE OPERATIONS MANAGEMENT WITH INTERNET-BASED APPLICATIONS FOR SUPPLY CHAIN MANAGEMENT AND SERVICE MANAGEMENT / [pt] METODOLOGIA EVOCATIVA PARA MAPEAMENTO CAUSAL E SUA PERSPECTIVA NA GERÊNCIA DE OPERAÇÕES COM APLICAÇÕES VIA INTERNET EM GESTÃO DA CADEIA DE SUPRIMENTO E ADMINISTRAÇÃO DE SERVIÇOS

25 August 2004 (has links)
[pt] A compreensão dos atuais processos produtivos é essencial neste momento em que o conhecimento tornou-se um importante gerador de valor. Uma visão holística dos conhecimentos que estão disseminados, de forma dispersa, entre profissionais, consultores e acadêmicos é necessária para a síntese de novas teorias da produção. Pesquisadores de gerência de operações freqüentemente usam mapeamento causal como um mecanismo para construir e comunicar teorias, particularmente em suporte à pesquisa empírica. As abordagens mais usuais para capturar dados cognitivos para um mapa causal são brainstorming e entrevistas, os quais exigem muito tempo e apresentam um significativo custo em sua implementação. Esta tese visa gerar uma metodologia (Metodologia Evocativa para Mapeamento Causal - ECMM) voltada para aplicação em pesquisa sobre gerência de operações para coletar e estruturar dados disseminados de forma desagregada, como conhecimento e experiência profissional e acadêmica, contidos nas opiniões de um grande número de especialistas dispersos demograficamente e geograficamente. Isto é alcançado evocando opiniões, codificando-as em variáveis e reduzindo o grupo em conceitos e relações. Tem-se uma especial preocupação em conseguir este objetivo em tempo factível e com baixo custo. A coleta de dados é assíncrona, via Internet, possui dois ou três turnos (à semelhança do método Delfos). A análise de dados usa codificação, técnica de grupamento hierárquica e escalamento multidimensional para identificar conceitos na forma de mapas cognitivos. A ECMM foi ilustrada com aplicações que demonstram sua viabilidade. Aplicou-se nas áreas de gestão da cadeia de suprimento (SCM) e administração de serviços (SM) com a participação de aproximadamente 1.300 respondentes de empresas e universidades de quase 100 países. Dentre os desdobramentos para pesquisas futuras propõe-se aplicar nas áreas de ECMM em SCM e SM visando a uni-las em um tema: gestão da cadeia de suprimento de serviços. / [en] The understanding of the present productive processes is essential at this moment when knowledge became an important value creator. A holistic vision of the pieces of knowledge that are spread out and dispersed among practitioners, consultants and academics is necessary for the synthesis of new theories of production. Operations management researchers often use causal mapping as a key tool for building and communicating theory, particularly in support of empirical research. The widely accepted approaches for capturing cognitive data for a causal map are informal brainstorming and interviews, which require a time- consuming and significant cost of implementation. This dissertation aims at creating a methodology (Evocative Causal Mapping Methodology - ECMM) intended for use in operations management research for collecting and structuring dispersed data spread out as practical and research knowledge, and experience contained in the opinions of a large number of specialists demographically and geographically scattered. This is accomplished by evoking opinions, encoding them into variables and reducing the resulting set to concepts and relationships. A special concern is to achieve this goal in a feasible time and cost- efficient way. ECMM consists of two or three round, Delphi- like, Internet-based asynchronous data collection, and a data analysis that uses a coding panel of experts, hierarchical cluster analysis and multidimensional scaling for identifying concepts on cognitive map formats. Applications illustrate ECMM and demonstrate its feasibility. They were developed on supply chain management (SCM) and service management (SM) involving about 1,300 respondents of companies and universities of about 100 countries. Among possible unfolding future studies, this dissertation proposes to apply ECMM in SCM and SM aiming at unifying them into a single topic: service supply chain management.
17

Srovnání algoritmů při řešení problému obchodního cestujícího / The Comparison of the Algorithms for the Solution of Travel Sales Problem

Kopřiva, Jan January 2009 (has links)
The Master Thesis deals with logistic module innovation of information system ERP. The principle of innovation is based on implementation of heuristic algorithms which solve Travel Salesman Problems (TSP). The software MATLAB is used for analysis and tests of these algorithms. The goal of Master Thesis is the comparison of selections algorithm, which are suitable for economic purposes (accuracy of solution, speed of calculation and memory demands).

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