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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.
21

Métodos lineares e não-lineares de análise de dados cronobiológicos de Melipona quadrifasciata (Hymenoptera, Meliponini) / Linear and nonlinear methods of chronobiological data analysis of Melipona quadrifasciata (Hymenoptera, Meliponini)

Talita de Cássia Glingani Sebrian 11 October 2011 (has links)
A Cronobiologia estuda a origem e a manifestação de ritmos biológicos nos mais diversos táxons. A análise dos dados obtidos experimentalmente, contudo, é bastante complexa, haja vista a restrita gama de métodos disponíveis para tal. Os osciladores que determinam a existência dos ritmos biológicos são exemplos de sistemas dinâmicos não-lineares, os quais estão amplamente distribuídos nos seres vivos. Esses sistemas, por suas peculiaridades, são melhor analisados por métodos não-lineares. O objetivo deste trabalho é testar diferentes métodos de análise séries temporais, tanto alguns classicamente empregados na Cronobiologia quanto métodos não-lineares, verificando sua empregabilidade e funcionalidade para dados cronobiológicos, bem como as propriedades que permitem ou não seu uso. Para tanto, foram utilizados dados de ritmos de consumo de O2 obtidos para diferentes grupos etários de operárias de Melipona quadrifasciata (Hymenoptera, Meliponini). Tais dados foram submetidos às seguintes análises: Transformada Rápida de Fourier (TRF), Análise de Potência Espectral (PSA), Estatística Circular (teste de Rayleigh), Teste de Estacionariedade (Teste da Raiz Unitária de Dickey-Fuller Aumentado - ADF), Plot de Poincaré, Entropia Aproximada (ApEn) e Entropia Aproximada Volumétrica (vApEn). Os resultados obtidos demonstram que os métodos não-lineares de análise detectam a existência de ritmo metabólico, assim como os métodos lineares utilizados por Teixeira (2006) e Camargo (em andamento) indicam sua presença. Ressalta-se, contudo, que há certa dificuldade em distinguir se a variabilidade existente nas séries deve-se, possivelmente, a seu comportamento determinístico ou a ruídos externos a elas, cuja detecção não é possível. Outro importante fator limitante da aplicabilidade das análises não-lineares é o número de pontos das séries temporais em questão, que era bastante reduzido nesse estudo. Dessa maneira, conclui-se que alguns métodos não-lineares, e.g. TRF, também são eficazes na detecção de ritmos biológicos, devendo ser observada a restrição devido ao tamanho da série temporal. / Chronobiology is the study of the origin and manifestation of rhythmical phenomena in all sorts of taxons. The analysis of the experimental obtained data is, however, still very complex due to the lack of availability of methods and techniques. The oscillators that determine the existence of rhythmical biological phenomena are examples of non-linear dynamic systems, which are widely spread among organisms. This research intends to present the result of a sort of temporal series analysis methods, some already used for Chronobiology research, as non-linear methods, testing their use and functionality for chronobiological data as well as determining their gaps and limitations for this purpose. For this research, data regarding to rhythm of O2 consumption were obtained from different age groups of Melipona quadrifasciata (Hymenoptera, Meliponini) workers. Such data were submitted to the following analysis: Fast Fourier Transform (FFT), Power Spectrum Analysis (PSA), Circular Statistics (Rayleigh\'s test), Stationarity Test (Unit Root Augmented Dickey-Fuller Test - ADF), Poincaré Plot, Approximate Entropy (ApEn) e Volumetric Approximate Entropy (vApEn). The results indicate that nonlinear methods detect the presence of metabolic rhythm, such as previous researches where linear methods used by Teixeira (2006) and Camargo (ongoing research) indicate its presence. However, there is some difficulty in determining if the variability present in the series is possibly due to its deterministic behavior or to the external noise, from which the determination is still not possible. Another limiting factor is the number of points of analyzed temporal series, which was very small. We conclude that some nonlinear methods, e.g. FFT, are effective to detect biological rhythms, but the constraint to time series length must be observed.
22

Utvärdering av temporala analysmetoder inom brottskategorin bostadsinbrott

Svenhag, Olle January 2015 (has links)
Context. In year 2013 the number of reported residential burglariesin Sweden was 21000, where only 4-5 percent of those actuallygot solved [1]. The Swedish police is trying to improve their way ofworking to increase the number of solved burglaries, this by structuringthe data collection and analysing with computer science methods.Temporal analysis is the key to gure out when crime actually takesplace. Objectives. This thesis study ve dierent methods for analysingthe temporal data of residential burglaries. The temporal analysis isperformed on three time spans: time of day, day of the week and dayof the month. The objective is to evaluate the ve methods in thethree time spans and decide which method is the most suitable foreach of them. Methods. This study includes three experiments testing all ve methodson the three time spans. The experiments focus on comparing theobserved data against the data of burglaries with a known specictime of the crime. In order to test the performance of each method aChi-squared goodness-of-t test was used, as well as a visual comparisonof the produced plots. Results. The results showed that the Aoristic-method was the mostsuitable method to use when analysing temporal data of residentialburglars, if looking at the time of day, day of the week and day ofthe month. Using the methods we also generated plots of the threetemporal distributions, with an R script. Conclusions. We concluded that using the Aoristic-method is themost suitable method to use to generate plots from the temporal data.We also concluded that using this script with the Aoristic-method togenerate plots, would make it possible for the police to resource allocationaccording to when burglaries actually take place.
23

Finanční analýza účetní jednotky ABC/Financial Analysis of Company ABC / Financial Analysis of Company ABC

Kaprálová, Aneta January 2009 (has links)
This thesis is focused on financial analysis of company ABC that works in rubber industry. First part is aimed at theoretical interpretation of financial analysis, its goals, history, users and sources. Attention is paid to sources of information especially financial statements. Further basic methods are defined, which financial analysis uses. Ratios are described in this thesis above all. At the close there is practical display of financial analysis based on data from financial statements of company ABC and its internal sources.
24

Detecção de danos em barras usando propagação de ondas e tempo reverso / Damage detection in rods using wave propagation and time reversal

Lucena, Raimundo Liberato, 1989- 27 August 2018 (has links)
Orientador: José Maria Campos dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T02:09:23Z (GMT). No. of bitstreams: 1 Lucena_RaimundoLiberato_M.pdf: 3221588 bytes, checksum: 2a3c7aed85d815f7b04f953992d3ac0e (MD5) Previous issue date: 2015 / Resumo: O monitoramento da integridade e detecção de danos em estruturas tem recebido considerável atenção nas últimas décadas. Houveram progressos significativos no desenvolvimento de métodos para a detecção de danos estruturais, com base nas técnicas de análise modal e resposta dinâmica do sistema. Estas técnicas têm se mostrado bastante apropriadas para detectar danos de alta intensidade, mas não para danos menores, tais como trincas. Um método alternativo é a utilização de métodos de propagação de ondas elásticas. Uma das vantagens é que as ondas guiadas viajam ao longo do comprimento da estrutura, o que permite um teste rápido de longo alcance e elimina a necessidade de se analisar todas as partes da amostra. Neste trabalho será apresentado um método não destrutivo para a detecção de danos em estruturas tipo barra. A fim de evitar uma demorada análise de toda a estrutura, como é feito com métodos clássicos de ultrassom, guias de ondas elásticas são utilizados. Ondas são excitadas e se propagam ao longo da amostra. Estas ondas interagem com um possível dano o que resulta no espalhamento da onda. Os sinais das ondas geradas pelo espalhamento são medidos em algumas posições. Estes sinais são revertidos no tempo e reinjetados nos mesmos pontos de aquisição sobre o modelo numérico da barra, fornecendo uma indicação da posição da falha. Esta combinação de experimento, tempo reverso e simulação numérica fornece uma ferramenta para a detecção de danos em grandes estruturas. O método foi desenvolvido e simulado em um código numérico para guias de onda tipo barra utilizando o Método do Elemento Espectral (Spectral Element Method - SEM). Exemplos simulados de todo o processo feito para uma barra simples são mostrados e os resultados discutidos e comparados com aqueles encontrados na literatura / Abstract: The health monitoring and damage detection in structures have received considerable attention in recent decades. There have been significant advances in the development of methods for structural damage detection based on the modal analysis techniques and dynamic system response. These techniques have shown to be quite appropriate for high-intensity detecting damages but not for minor damages such as cracks. An alternative method is the use of elastic waves propagation methods. The advantage is that the guided waves travel along the length of the structure, which allows a quick test of long range and eliminates the necessity of analyzing all peer samples. In this work a non-destructive method for damage detection in rod-like structures will be presented. In order to avoid a time-consuming scan of the entire structure, as is done with traditional ultrasound methods, elastic wave guides are used. Waves are excited and propagate along the sample. These waves interact with a possible damage which results in the scattering of the wave. The signals generated by scattering of waves are measured in some positions. These signals are reversed in time and re-injected at the same points of acquisition over the numerical model of the rod, providing an indication of the damage position. This combination of experiment, time reversal and numerical simulation gives a tool for damage detection in large structures. The method was developed and simulated in a numeric code for a rod waveguide using the Spectral Element Method (SEM). Simulated examples of the entire process made for a single rod are shown and results discussed and compared with those found in the literature / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica
25

Hodnocení finanční situace podniku a návrhy na její zlepšení / Evulation of the Financial Situation in the Firm and Proposals to its Improvement

Matoušek, David January 2009 (has links)
This thesis evaluates the financial and economic situation of the company Železárny Štěpánov, spol s. r.o. It uses a prime financial analysis methods based on financial statements from the time period of 2004 –2007. Besides the theoretical and the analytic part contains suggestions and recomendations for an improvement of the company´s current position with regards to company opportunities and strategy of its future enterprise.
26

Alternative Sampling and Analysis Methods for Digital Soil Mapping in Southwestern Utah2

Brungard, Colby W 01 December 2009 (has links)
Digital soil mapping (DSM) relies on quantitative relationships between easily measured environmental covariates and field and laboratory data. We applied innovative sampling and inference techniques to predict the distribution of soil properties, soil attributes, taxonomic classes, and dominant vegetation across a 30,000-ha complex Great Basin landscape in southwestern Utah. This arid rangeland was characterized by rugged topography, diverse vegetation, and intricate geology. Environmental covariates calculated from digital elevation models (DEM) and spectral satellite data were used to represent factors controlling soil development and distribution. We investigated optimal sample size and sampled the environmental covariates using conditioned Latin Hypercube Sampling (cLHS). We demonstrated that cLHS, a type of stratified random sampling, closely approximated the full range of variability of environmental covariates in feature and geographic space with small sample sizes. Site and soil data were collected at 300 locations identified by cLHS. Random forests was used to generate spatial predictions and associated probabilities of site and soil characteristics. Balanced random forests and balanced and weighted random forests were investigated for their use in producing an overall soil map. Overall and class errors (referred to as out-of-bag [OOB] error) were within acceptable levels. Quantitative covariate importance was useful in determining what factors were important for soil distribution. Random forest spatial predictions were evaluated based on the conceptual framework developed during field sampling.
27

Transcriptional and genetic profiling of human uveal melanoma from an immunosuppressed rabbit model

Marshall, Jean-Claude. January 2007 (has links)
No description available.
28

Optical Properties of Rydberg Excitons in Cuprous Oxide

Jacob C DeLange (15209836) 12 April 2023 (has links)
<p>Cuprous oxide (Cu<sub>2</sub>O) has recently been proposed as a promising solid-state host for ex-<br> citonic Rydberg states with large principal quantum numbers (n) whose exaggerated wave-<br> function sizes (∝ n<sup>2</sup>) facilitate gigantic, resonant dipole-dipole (∝ n<sup>4</sup>) and van der Waals<br> (∝ n<sup>11</sup>) interactions, making them an ideal basis for solid-state Rydberg physics and quan-<br> tum technology. Synthetic, thin-film Cu<sub>2</sub>O samples are of particular interest because they<br> can be made defect-free via carefully controlled fabrication and are, in principle, suitable<br> for the observation of extreme single-photon nonlinearities caused by Rydberg blockade. In<br> this work, we present the development of a spectroscopy experiment for characterizing the<br> behavior of Rydberg excitons and use it to study a synthetic thin film of Cu<sub>2</sub>O grown on a<br> transparent substrate. We present evidence for the presence of states up to n = 8 and conduct<br> the first temperature-dependent study of Rydberg excitons in a thin film. We also propose<br> a technique for studying Rydberg-Rydberg interactions via the creation of high exciton den-<br> sities and establish a set of rate equations for modeling the processes by which excitons are<br> created, interact with each other, and decay. Finally, we conclude with a discussion of the<br> project’s outlook, as well as what future work will be undertaken to study the interactions<br> between Rydberg excitons and utilize them in scalable, integrable, Rydberg-based quantum<br> devices.<br> </p>
29

Complications In Clinical Trials: Bayesian Models For Repeated Measures And Simulators For Nonadherence

Ahmad Hakeem Abdul Wahab (11186256) 28 July 2021 (has links)
<p>Clinical trials are the gold standard for inferring the causal effects of treatments or interventions. This thesis is concerned with the development of methodologies for two problems in modern clinical trials. First is analyzing binary repeated measures in clinical trials using models that reflect the complicated autocorrelation patterns in the data, so as to obtain high power when inferring treatment effects. Second is simulating realistic outcomes and subject nonadherence mechanisms in Phase III pharmaceutical clinical trials under the Tripartite Framework.</p><p> </p><p><b>Bayesian Models for Binary Repeated Data: The Bayesian General Logistic Autoregressive Model and the Polya-Gamma Logistic Autoregressive Model</b></p><p>Autoregressive processes in generalized linear mixed effects regression models are convenient for the analysis of clinical trials that have a moderate to large number of binary repeated measurements, collected across a fixed set of structured time points, for each subject. However, much of the existing literature and methods for autoregressive processes on repeated binary measurements permit only one order and only one autoregressive process in the model. This limits the flexibility of the resulting generalized linear mixed effects regression model to fully capture the dynamics in the data, which can result in decreased power for testing treatment effects. Nested autoregressive structures enable more holistic modeling of clinical trials that can lead to increased power for testing effects.</p><p> </p><p>We introduce the Bayesian General Logistic Autoregressive Model (BGLAM) for the analysis of repeated binary measures in clinical trials. The BGLAM extends previous Bayesian models for binary repeated measures by accommodating flexible and nested autoregressive processes with non-informative priors. We describe methods for selecting the order of the autoregressive process in the BGLAM based on the Deviance Information Criterion (DIC) and marginal log-likelihood, and develop an importance sampling-weighted posterior predictive p-value to test for treatment effects in BGLAM. The frequentist properties of BGLAM compared to existing likelihood- and non-likelihood-based statistical models are evaluated by means of extensive simulation studies involving different data generation mechanisms.</p><p> </p><p>Two features of BGLAM that can limit its application in practice is the computational effort involved in executing it and the inability to integrate added heterogeneity across time in its autoregressive processes. We develop the Polya-Gamma Logistic Autoregressive Model (PGLAM) for addressing these limiting features of the BGLAM. This new model enables the integration of additional layers of variability through random effects and heterogeneity across time in nested autoregressive processes. Furthermore, PGLAM is computationally more efficient than BGLAM because it eliminates the need to use the complex types of samplers for truncated latent variables that is involved in the Markov Chain Monte Carlo algorithm for BGLAM.</p><p> </p><p><b>Data Generating Model for Phase III Clinical Trials With Intercurrent Events</b></p><p>Although clinical trials are designed with strict controls, inevitably complications will arise during the course of the trials. One significant type of complication is missing subject outcomes due to subject drop-out or nonadherence during the trial, which are referred to in general as intercurrent events. This complication can arise from, among other causes, adverse reactions, lack of efficacy of the assigned treatment, administrative reasons, and excess efficacy from the assigned treatment. Intercurrent events typically confound causal inferences on the effects of the treatments under investigation because the missingness that occurs as a result corresponds to a Missing Not at Random missing data mechanism, the pharmaceutical industry is increasingly focused on developing methods for obtaining valid causal inferences on the receipt of treatment in clinical trials with intercurrent events. However, it is extremely difficult to compare the frequentist properties and performance of these competing methods, as real-life clinical trial data cannot be easily accessed or shared, and as the different methods consider distinct assumptions for the underlying data generating mechanism in the clinical trial. We develop a novel simulation model for clinical trials with intercurrent events. Our simulator operates under the Rubin Causal Model. We implement the simulator by means of an R Shiny application. This app enables users to control patient compliance through different sources of discontinuity with varying functional trends, and understand the frequentist properties of treatment effect estimators obtained by different models for various estimands.</p>
30

Determination of the 3D Load System for Space Closure Using Keyhole and Teardrop Closing Loops in a Full Arch

Gajda, Steven W. January 2008 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The current movement in dentistry is to provide treatment that is evidence-based rather than opinion-based. Unfortunately, there is a lack of evidence for most orthodontic appliances. Much work has been done to find the appropriate load system to move teeth, but research has only been done with laboratory techniques that may not be applied clinically. Ideally, appliances should be tested in all three dimensions with techniques (e.g. type of ligation) that replicate clinical procedures. This can be accomplished with a new patented technology, the orthodontic force tester (OFT). The OFT allows an entire arch with brackets and a full arch wire to be set up while measurements are made on target teeth. With the OFT, appliances can be tested to ascertain if they provide the prescribed load system, and if not, then modify them or develop new ones. In this experiment two different commercially available prefabricated closing loop arch wires (keyhole and teardrop) were tested with variations in gable bends, interbracket loop position, and activation. The application being tested is closing space between a lateral incisor and canine in a first premolar extraction case after the canine has been retracted. While the trend shows that the keyhole loop produces higher overall force the two loops are not significantly different in the forces or moments that they generate. The one exception is that the keyhole loop produces higher lingual forces at the canine when the loop is in the mesial position. Also, few wire configuration were able to produce M/F sufficient to translate teeth. The wire configurations that can provide the proper load system to translate teeth in the lingual direction at the incisor were in the mesial position and had second order gable bends at the alpha position. The loop design had little effect on the M/F ratios.

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