Global ETD Search

441	Development of methods for characterizing plant and stand architectures and for model comparisons Dzierzon, Helge 07 November 2003 (has links) No description available. Forest Sciences and Forest Ecology Forstwissenschaft Biometrie Regelbasierte Bestandesmodellierung L-Systeme Strukturmodelle Struktur-Funktions-Modelle Bestandesarchitektur Naturverjüngung LIGNUM Aggregation Modellvergleich 500 Naturwissenschaften Forest Science Biometry Rule Based Tree Stand Modelling Tree Stand Architecture Regeneration LIGNUM Structural Models Structural-Funktional Models Aggregation Model Comparison 48 Land- und Forstwirtschaft RA 000: Allgemeine Naturwissenschaften
442	Caractéristiques maternelles, performances et stratégies de reproduction des tortues marines de Guyane / Maternal characteristics, reproductive output and reproductive strategies in sea turtles of French Guiana Plot, Virginie 17 December 2012 (has links) Les organismes font face à des compromis entre leur reproduction, leur maintenance et leur survie, dont découlent des stratégies adaptatives énergétiques, comportementales et écologiques.Ce travail de thèse propose de préciser les stratégies de reproduction chez la tortue luth Dermochelys coriacea nidifiant en Guyane. Nous avons étudié les caractéristiques maternelles, les performances de reproduction et les potentiels liens existants entre la migration et la reproduction chez une population d’individus d’identité connue, suivis grâce à un suivi longitudinal original combinant biométrie, physiologie et biologie moléculaire.Premièrement nous montrons que les tortues luth opèrent comme des reproducteurs sur capital, i.e., leur reproduction repose sur les ressources stockées sous forme de réserves corporelles pendant la migration précédant la saison de ponte. D’autre part, nous suggérons que les femelles ajustent la durée de leur migration en fonction des conditions océanographiques rencontrées pendant la migration. Ceci leur permettrait, à l’échelle de la vie, de répondre au compromis entre la reproduction en cours et les reproductions futures. Enfin, notre démarche souligne l’importance de prendre en compte les caractéristiques individuelles dans la compréhension des stratégies de reproduction, et de manière ultime pour l’établissement de modèles réalistes de la dynamique des populations, notamment dans le cas d’espèces emblématiques telles que les tortues marines. / Organisms face trade-offs between their reproduction, maintenance and survival, from which result adaptative strategies at the energetics, behavioural and ecological levels.This PhD work investigates the reproductive strategies used by leatherback turtles, Dermochelys coriacea, nesting in French Guiana. We investigated maternal characteristics, reproductive output, and the possible links between migration and reproduction in a population of known identity, studied through a unique longitudinal monitoring, based on complementary approaches combining biometry, physiology and molecular biology.First, we found that leatherback turtles are capital breeders, i.e. females’ reproductive output displayed during their nesting season relies on body reserves previously stored during their migration. Second, we suggested that leatherback females adjust the duration of the migration according to the oceanographic conditions they experienced during migration. At a lifetime scale, this may allow females to face the trade-off between current and future reproductions. Finally, our approach highlights the importance to take into account individual characteristics in order to better understand reproductive strategies, and further assess realistic models of population dynamics, particularly when considering emblematic species such as sea turtles. Tortues marines Stratégies de reproduction Compromis Tortue luth Dermochelys coriacea Suivi longitudinal Biométrie Physiologie Télomères Reproduction sur capital Modes de migration Conditions environnementales Sea turtles Reproductive strategies Trade-offs Leatherback turtle Dermochelys coriacea Longitudinal monitoring Biometry Physiology Telomeres Capital breeder Migration’s patterns Environmental conditions 577.7 591.56
443	Central de confrontos para um sistema automático de identificação biométrica: uma abordagem de implementação escalável / Matching platform for an automatic biometric identification system: a scalable implementation approach Nishibe, Caio Arce 19 October 2017 (has links) Com a popularização do uso da biometria, determinar a identidade de um indivíduo é uma atividade cada vez mais comum em diversos contextos: controle de acesso físico e lógico, controle de fronteiras, identificações criminais e forenses, pagamentos. Sendo assim, existe uma demanda crescente por Sistemas Automáticos de Identificação Biométrica (ABIS) cada vez mais rápidos, com elevada acurácia e que possam operar com um grande volume de dados. Este trabalho apresenta uma abordagem de implementação de uma central de confrontos para um ABIS de grande escala utilizando um framework de computação em memória. Foram realizados experimentos em uma base de dados real com mais de 50 milhões de impressões digitais em um cluster com até 16 nós. Os resultados mostraram a escalabilidade da solução proposta e a capacidade de operar em grandes bases de dados. / With the popularization of biometrics, personal identification is an increasingly common activity in several contexts: physical and logical access control, border control, criminal and forensic identification, payments. Thus, there is a growing demand for faster and accurate Automatic Biometric Identification Systems (ABIS) capable to handle a large volume of biometric data. This work presents an approach to implement a scalable cluster-based matching platform for a large-scale ABIS using an in-memory computing framework. We have conducted some experiments that involved a database with more than 50 million captured fingerprints, in a cluster up to 16 nodes. The results have shown the scalability of the proposed solution and the capability to handle a large biometric database. Biometria Identificação biométrica Computação de alto desempenho Big data Antropometria Impressões digitais Sistemas de memória de computadores Engenharia elétrica Biometry Biometric identification High performance computing Big data Anthropometry Fingerprints Computer storage devices Electric engineering Engenharia Elétrica
444	Software pro biometrické rozpoznávání duhovky lidského oka / Software for Biometric Recognition of a Human Eye Iris Maruniak, Lukáš January 2015 (has links) In my thesis, I focus on the task of recognizing human iris from an image.In the beginning, the work deals with a question of biometrics, its importance and basic concepts, which are necessary for use in following text. Subsequently process of human Iris detection is described together with theory of evolution algorithms. In the implementation part, is described the design of implemented solution, which uses evolution algorithms, where is emphasis on correct pupil and iris boundary detection.
445	Variable selection and structural discovery in joint models of longitudinal and survival data He, Zangdong January 2014 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Joint models of longitudinal and survival outcomes have been used with increasing frequency in clinical investigations. Correct specification of fixed and random effects, as well as their functional forms is essential for practical data analysis. However, no existing methods have been developed to meet this need in a joint model setting. In this dissertation, I describe a penalized likelihood-based method with adaptive least absolute shrinkage and selection operator (ALASSO) penalty functions for model selection. By reparameterizing variance components through a Cholesky decomposition, I introduce a penalty function of group shrinkage; the penalized likelihood is approximated by Gaussian quadrature and optimized by an EM algorithm. The functional forms of the independent effects are determined through a procedure for structural discovery. Specifically, I first construct the model by penalized cubic B-spline and then decompose the B-spline to linear and nonlinear elements by spectral decomposition. The decomposition represents the model in a mixed-effects model format, and I then use the mixed-effects variable selection method to perform structural discovery. Simulation studies show excellent performance. A clinical application is described to illustrate the use of the proposed methods, and the analytical results demonstrate the usefulness of the methods. Joint models Mixed effect selection Structural discovery Adaptive LASSO Gaussian quadrature EM algorithm Regression analysis -- Data processing Numerical analysis -- Data processing Spectral theory (Mathematics) Estimation theory -- Analysis Statistics -- Data processing Calculus of variations Structural bioinformatics Parameter estimation
446	Multivariate semiparametric regression models for longitudinal data Li, Zhuokai January 2014 (has links) Multiple-outcome longitudinal data are abundant in clinical investigations. For example, infections with different pathogenic organisms are often tested concurrently, and assessments are usually taken repeatedly over time. It is therefore natural to consider a multivariate modeling approach to accommodate the underlying interrelationship among the multiple longitudinally measured outcomes. This dissertation proposes a multivariate semiparametric modeling framework for such data. Relevant estimation and inference procedures as well as model selection tools are discussed within this modeling framework. The first part of this research focuses on the analytical issues concerning binary data. The second part extends the binary model to a more general situation for data from the exponential family of distributions. The proposed model accounts for the correlations across the outcomes as well as the temporal dependency among the repeated measures of each outcome within an individual. An important feature of the proposed model is the addition of a bivariate smooth function for the depiction of concurrent nonlinear and possibly interacting influences of two independent variables on each outcome. For model implementation, a general approach for parameter estimation is developed by using the maximum penalized likelihood method. For statistical inference, a likelihood-based resampling procedure is proposed to compare the bivariate nonlinear effect surfaces across the outcomes. The final part of the dissertation presents a variable selection tool to facilitate model development in practical data analysis. Using the adaptive least absolute shrinkage and selection operator (LASSO) penalty, the variable selection tool simultaneously identifies important fixed effects and random effects, determines the correlation structure of the outcomes, and selects the interaction effects in the bivariate smooth functions. Model selection and estimation are performed through a two-stage procedure based on an expectation-maximization (EM) algorithm. Simulation studies are conducted to evaluate the performance of the proposed methods. The utility of the methods is demonstrated through several clinical applications. Biostatistics Estimation theory -- Research Biometry -- Methodology -- Research Binary system (Mathematics) -- Research Nonparametric statistics -- Research Probabilities -- Data processing Real-time data processing -- Research Parameter estimation -- Research Latent variables -- Research Meta-analysis -- Research -- Methodology Stochastic processes -- Research Least squares -- Research
447	Application Of The Empirical Likelihood Method In Proportional Hazards Model He, Bin 01 January 2006 (has links) In survival analysis, proportional hazards model is the most commonly used and the Cox model is the most popular. These models are developed to facilitate statistical analysis frequently encountered in medical research or reliability studies. In analyzing real data sets, checking the validity of the model assumptions is a key component. However, the presence of complicated types of censoring such as double censoring and partly interval-censoring in survival data makes model assessment difficult, and the existing tests for goodness-of-fit do not have direct extension to these complicated types of censored data. In this work, we use empirical likelihood (Owen, 1988) approach to construct goodness-of-fit test and provide estimates for the Cox model with various types of censored data. Specifically, the problems under consideration are the two-sample Cox model and stratified Cox model with right censored data, doubly censored data and partly interval-censored data. Related computational issues are discussed, and some simulation results are presented. The procedures developed in the work are applied to several real data sets with some discussion. Dissertations Academic -- Sciences Sciences -- Dissertations Academic Statistical hypothesis testing Survival analysis (Biometry) Bootstrap Confidence interval Cox model Doubly censored data Empirical likelihood function Goodness of fit test Maximum likelihood Partly interval censored data Proportional hazards model Right censored data Survival analysis Mathematics
448	Ursachen des Invasionserfolges von Rhododendron ponticum L. auf den Britischen Inseln: Einfluss von Habitat und Genotyp / The invasion success of Rhododendron ponticum L. in the British Isles: effects of habitat and genotypes Erfmeier, Alexandra 27 April 2004 (has links) No description available. 580 Pflanzen (Botanik) Mathematics and Computer Science Biologische Invasionen Biometrie Blattmerkmale Common Garden Experiment Genetische Veränderung Hierarchisches Beprobungsdesign Invasibilität Invasivität Keimlingsetablierung Keimraten Keimungsgeschwindigkeit Lokale Anpassung Populationsökologie release hypothesis Ressourcen-Verfügbarkeit Rhododendron ponticum Verpflanzungsexperiment Wachstumsraten biological invasions biometry common garden experiment genetic shift germination rates germination velocity growth rates invasibility invasiveness leaf characteristics local adaptation nested sampling design population ecology release hypothesis ressource availability Rhododendron ponticum seedling establishment transplant experiment 42.07 42.44 WL WN
449	Joint models for longitudinal and survival data Yang, Lili 11 July 2014 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Epidemiologic and clinical studies routinely collect longitudinal measures of multiple outcomes. These longitudinal outcomes can be used to establish the temporal order of relevant biological processes and their association with the onset of clinical symptoms. In the first part of this thesis, we proposed to use bivariate change point models for two longitudinal outcomes with a focus on estimating the correlation between the two change points. We adopted a Bayesian approach for parameter estimation and inference. In the second part, we considered the situation when time-to-event outcome is also collected along with multiple longitudinal biomarkers measured until the occurrence of the event or censoring. Joint models for longitudinal and time-to-event data can be used to estimate the association between the characteristics of the longitudinal measures over time and survival time. We developed a maximum-likelihood method to joint model multiple longitudinal biomarkers and a time-to-event outcome. In addition, we focused on predicting conditional survival probabilities and evaluating the predictive accuracy of multiple longitudinal biomarkers in the joint modeling framework. We assessed the performance of the proposed methods in simulation studies and applied the new methods to data sets from two cohort studies. / National Institutes of Health (NIH) Grants R01 AG019181, R24 MH080827, P30 AG10133, R01 AG09956. joint models longitudinal data survival data bivariate change point models prediction Bayesian method EM algorithm Biologically-inspired computing Probability measures Expectation-maximization algorithms Failure time data analysis Numerical analysis -- Data processing Clinical trials -- Statistical methods
450	Dietary intake and urinary excretion of phytoestrogens in relation to cancer and cardiovascular disease Reger, Michael Kent January 2014 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Phytoestrogens that abound in soy products, legumes, and chickpeas can induce biologic responses in animals and humans due to structural similarity to 17β-estradiol. Although experimental studies suggest that phytoestrogen intake may alter the risk of cancer and cardiovascular disease, few epidemiologic studies have investigated this research question. This dissertation investigated the associations of intake of total and individual phytoestrogens and their urinary biomarkers with these chronic conditions using data previously collected from two US national cohort studies (NHANES and PLCO). Utilizing NHANES data with urinary phytoestrogen concentrations and follow-up mortality, Cox proportional hazards regression (HR; 95% CI) were performed to evaluate the association between total cancer, cardiovascular disease, and all-cause mortality and urinary phytoestrogens. After adjustment for confounders, it was found that higher concentrations of lignans were associated with a reduced risk of death from cardiovascular disease (0.48; 0.24-0.97), whereas higher concentrations of isoflavones (2.14; 1.03-4.47) and daidzein (2.05; 1.02-4.11) were associated with an increased risk. A reduction in all-cause mortality was observed for elevated concentrations of lignans (0.65; 0.43-0.96) and enterolactone (0.65; 0.44-0.97). Utilizing PLCO data and dietary phytoestrogens, Cox proportional hazards regression examined the associations between dietary phytoestrogens and the risk of prostate cancer incidence. After adjustment for confounders, a positive association was found between dietary intake of isoflavones (1.58; 1.11-2.24), genistein (1.42; 1.02-1.98), daidzein (1.62; 1.13-2.32), and glycitein (1.53; 1.09-2.15) and the risk of advanced prostate cancer. Conversely, an inverse association existed between dietary intake of genistein and the risk of non-advanced prostate cancer (0.88; 0.78-0.99) and total prostate cancer (0.90; 0.81-1.00). C-reactive protein (CRP) concentration levels rise in response to inflammation and higher levels are a risk factor for some cancers and cardiovascular disease reported in epidemiologic studies. Logistic regression performed on NHANES data evaluated the association between CRP and urinary phytoestrogen concentrations. Higher concentrations of total and individual phytoestrogens were associated with lower concentrations of CRP. In summary, dietary intake of some phytoestrogens significantly modulates prostate cancer risk and cardiovascular disease mortality. It is possible that these associations may be in part mediated through the influence of phytoestrogen intake on circulating levels of C-reactive protein. Epidemiology Phytoestrogens Nutrition Cancer Cardiovascular Disease C-reactive protein Epidemiology -- Research -- Methodology Epidemiology -- Statistical methods Cancer -- Epidemiology Phytoestrogens -- Health aspects C-reactive protein -- Research Nutrition -- Evaluation -- Research Genistein -- Research Logistic regression analysis Biochemical markers -- Research Lignans -- Research Regression analysis Survival analysis (Biometry)

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