The occurrence of some diatoms depends on degree of pollution and water quality. Due to this attribute are diatoms used as indicators for the environmental bioassessment. But the maximum use of diatoms for this purpose is complicated by high number of species which are defined based on the ultrastructural morphological features which are indistinguishable without the electron microscope. The aims of this study were to find out the influence of environmental factors, types of habitat and geography on the structure of diatom community. And find out if richness of higher taxonomic levels is correlated with species richness, in this case if it responds with the genetic diversity within diatom species complex Frustulia crassinervia-saxonica. In this study, 49 permanent slides from natural samples were analyzed. Samples were taken from benthos of different types of freshwater habitat - lakes, dams, pools, peat bogs, stream, wet wall on diverse localities in Europe, Canada, Greenland, Chile and New Zealand. In all slides were counted 300 cells which were determined based on the morphological features on genera level. Altogether 43 benthic genera were identified. The results of this thesis showed that number of genera correlated with pH gradient but do not correlate with other environmental factors -...

The study seeks to determine the effect upon the Marascuilo Ú₀ statistic of violating the small sample assumption. The study employed a Monte Carlo simulation technique to vary the degree of sample size and unequal sample sizes within experiments to determine the effect of such conditions, Twenty-two simulations, with 1200 trials each, were used. The following conclusion appeared to be appropriate: The Marascuilo Ú₀ statistic should not be used with small sample sizes and it is recommended that the statistic be used only if sample sizes are larger than ten.

Orientador: Franco Giuseppe Dedini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-24T21:14:00Z (GMT). No. of bitstreams: 1 NacerColmenero_Alberto_M.pdf: 9387560 bytes, checksum: 8ce3464ab75b288b4b8a9e8615aa96da (MD5) Previous issue date: 1999 / Resumo: Neste trabalho apresenta-se um estudo sobre os aspectos básicos relacionados com os ensaios acelerados utilizados na industria, são apresentados alguns conceitos fundamentais para o melhor entendimento da temática, as relações estresse x vida e distribuições de vida mais utilizadas. Do estudo realizado, foi escolhida uma metodologia para analisar os ensaios acelerados de vida, diferente à que é empregada em muitas industrias atualmente, baseada em um tipo de planejamento aleatorizado por níveis. Por último é apresentado um programa para o processamento dos dados provenientes de ensaios acelerados com estresse constante e modo de falha simples, para dados completos, e com censura a direita ou múltipla, utilizando a distribuição de Weibull, Log-normal e Normal, combinadas com os modelos mais utilizados (Arrhenius e Lei da Potência Inversa), o programa permite o processamento dos dados dos ensaios acelerados por dois métodos, Mínimos Quadrados e Máxima Verossimilhança, o primeiro oferece os estimados iniciais para aplicar o método de Máxima Verossimilhança, e assim assegurar a convergência do método de Newton-Raphson para todos os casos. Outras saídas do programa são; gráficos de residuais, de probabilidades vs. tempo, estresse vs. percentuais, etc. No programa são utilizados testes estatísticos para a validação dos ensaios, dando a possibilidade de utilizar diferentes níveis de confiança para calcular os intervalos de confiança dos parâmetros utilizados / Abstract: This work presents a study on the basie aspects related with the accelerated tests used in the industry, some fundamental concepts are presented for the best understanding of the thematic, the relationships stress x life and the more applied life distributions. A methodology was chosen to analyze the accelerated life tests, different from that commonly applied now in a lot of industries, based on a type of ramdomic planning by levels. Last a software is presented for the processing of the accelerated tests data with constant stress and simple failure mode, for complete data, and with right or multiple censored tests, using the Weibull, Log-normal and Normal distributions, combined with the most used models (Arrhenius model and the Inverse Power Law), the program allows the processing of the accelerated tests data by two methods, Minimum Square and Maximum Likelihood, the first offers the evaluated initial values to apply the method of Maximum Likelihood, and in this way to assure the convergence of the method of Newton-Raphson for alI the cases. Other outputs of the software are; graphs of the residual, probabilities vs. time, stress vs. percentile, ete. In the program, statistical tests are used for the validation of the tests, giving the possibility to use different confidence levels to calculate the confidence intervals of the parameters of interest / Mestrado / Projeto Mecanico / Mestre em Engenharia Mecânica

Diploma thesis extends my Bachelor´s thesis, which was about methods of time distribution of precipitations and differences in that distribution within a small area. The first part of the paper describes the formation and distribution of precipitation, typical variation of precipitation and some characteristics, revealing and describing the behaviour of rainfall in a given station. Following part describes possible methods of evaluation of time distribution. Statistical methods are presented mainly here. Here described methods and evaluations are subsequently applied in time series of daily precipitations, which has been available for this work for the Jenin creek basin. The analysis is focused on characteristics and evaluation of rainfall between terms 1980 - 1988 and 2005 - 2013. The results show us some differences between terms in rainfall characteristics. However, mostly they are not statistically significant. The work also evaluates differences in rainfall totals between rainfall stations Jenín and Dolní Dvořiště (approximate distance of the stations is 4 km) in 2005 - 2013 term. During the evaluation it comes to differences in rainfall totals. They are highly variable and they don´t have neither constant direction nor size.

This diploma thesis disserts mainly on the software application development created through language Visual Basic for Application, which serves to creation of macros and automation of work in Microsoft Excel. The Application is made specially for company PENTACO, spol. s.r.o. The software allows to calculate complete financial analysis of company for last 8 years. Statistical methods are used for prediction of future indicators. The financial analysis will reveal the weaknesses and strengths of the company and on their basis will be suggested solutions for fixing of problems and company situation.

The diploma thesis evaluates the economic situation of BPS Bicycle Industrial s. r. o. time series analysis. The theoretical part describes financial indicators, time series analyzes and regression and correlation analysis. Based on the analyzes, suggestions were made to improve the current situation of the company. BPS has proven to be financially sound. Shortcomings to improvement were identified from the analyzes. For example, share of equity and debt, use of surplus funds and turnover of receivables and payables. This ratio needs to be addressed through greater use of debt. The system of sanctions is solution for problem the turnover of receivables and the use of surplus funds by investing in shares.

The thesis deals with the assessment of the economic situation of a selected company using statistical methods. The theoretical part describes the financial indicators, time series and regression analysis. The analytical part contains the calculation of selected indicators, which are subjected to statistical analysis. Based on the statistical analysis, the future development of indicators in the next two years is predicted. The last part contains suggestions that can lead to the improvement of the current situation of the company.

Partant de problématiques statistiques rencontrées dans l'étude du traitement antirétroviral des adultes infectés par le virus de l'immunodéficience humaine (VIH) en Afrique subsaharienne, cette thèse cherche, d'une part, à favoriser la vulgarisation d'outils méthodologiques relativement récents auprès d'un public d'utilisateurs moins avertis et, d'autre part, à participer au développement de nouveaux outils. Le premier chapitre présente différentes méthodes de modélisation des données longitudinales dont des méthodes d'analyse de l'évolution d'un critère au cours du temps (les modèles linéaires mixtes généralisés et les modèles d'équations d'estimation généralisées) ou de la survenue d'un évènement au cours du temps (le modèle semi-paramétrique de Cox et ses extensions à la prise en compte des covariables dépendantes du temps et de la censure informative). Le deuxième chapitre s'intéresse aux tests de non-infériorité et propose deux développements de la procédure classique de ces tests pour les cas où la marge de non-infériorité est relative. Enfin, le troisième chapitre aborde la question des données manquantes et propose une extension de la méthode d'imputation multiple par les distributions conditionnelles univariées qui consiste à prendre en compte des effets non-linéaires des covariables dans les modèles d'imputation par des fonctions B-splines. Ces méthodes sont illustrées par des études sur le VIH au Cameroun et au Sénégal. / On the basis of statistical challenges encountered in study of antiretroviral treatment of adults infected with human immunodeficiency virus (HIV) in sub-Saharan Africa, this thesis aims to promote the dissemination of relatively recent methodological tools of less aware audience of users on one hand and to participate to development of new tools on the other hand. The first chapter presents various methods for modeling longitudinal data of which analysis methods for changing of a criterion over time (the generalized linear mixed models and models of generalized estimating equations) or the occurrence of an event over time (the semi-parametric Cox model and its extensions to take into account time-dependent covariates and informative censoring). The second chapter focuses on non-inferiority test and provides two developments of the classical procedure of these tests in cases where the non-inferiority margin is relative. The third chapter addresses the question of missing data and proposes an extension of the multiple imputation method based on fully conditional specification, to take into account nonlinear effects of covariates in the imputation models using B-splines functions. These methods are illustrated by studies on HIV in Cameroon and Senegal.

The diploma thesis deals with an assessment of the topical financial situation of BARVY A LAKY TELURIA, s. r. o. using the time series analysis. The theoretical part focuses on the description of the financial indicators, analysis of the time series, and subsequently the regressive and correlative analysis. In the practical part, selected financial indicators are statistically analyzed. The future two-year development of indicators is predicted on the basis of the selected models; subsequently dependencies among the particular indicators are determined. In the conclusion, proposals to ameliorate the current financial situation of the company are recommended, which was carried out on the basis of the identified shortcomings.

The diploma thesis is focused on the creation of a program enabling calculation of selected economic indicators of Arbela s.r.o. The thesis is divided into a theoretical and practical part. The content of the theoretical part is a description of individual methods and procedures of financial analysis, description of principles of time series, and regression analysis. In the practical part, the program created to calculate the selected economic indicators of the company Arbela s.r.o. is presented. These indicators are subsequently evaluated and foreseeable development of the company is determined for the future. At the end of the thesis, solutions for possible improvement of the economic situation of the company can be found.