No description available.

No description available.

Testing the homogeneity of variances is an important problem in many applications since statistical methods of frequent use, such as ANOVA, assume equal variances for two or more groups of data. However, testing the equality of variances is a difficult problem due to the fact that many of the tests are not robust against non-normality. It is known that the kurtosis of the distribution of the source data can affect the performance of the tests for variance. We review the classical tests and their latest, more robust modifications, some other tests that have recently appeared in the literature, and use bootstrap and permutation techniques to test for equal variances. We compare the performance of these tests under different types of distributions, sample sizes and true ratios of variances of the populations. Monte-Carlo methods are used in this study to calculate empirical powers and type I errors under different settings.

No description available.

No description available.

No description available.

No description available.

No description available.

Att sätta sig in i andra utvecklares kod kan vara svårt och tidskrävande. Kodkonventionerär framtagna i syfte att underlätta underhållsarbetet för andra utvecklare som arbetar medsamma projekt, då det sällan är personen som skrev programmet som sedan underhållersamma program. För lite fokus läggs på kvalitétsaspekten i utvecklingsfasen av projektvilket kostar företag pengar och resurser. Denna studie har för avsikt att undersöka hurhögskoleingenjörsstudenter inom datateknik vid olika lärosäten i Sverige förhåller sig tillJavas kodkonventioner, och om det går att urskilja en signifikant skillnad i kodkvalitémellan lärosäten i avseende på identifierare, kommentarer samt format och struktur. Enwebbenkätundersökning genomfördes vars empiri analyserades med hjälp av ANOVA somär en vedertagen metod för hypotesprövning. 21 av 23 ANOVA-test visade att ingen signifikantskillnad förekom mellan lärosätena i avseende på identifierare, kommentarer samtformat och struktur. Resultatet visade även att de kvalitétsaspekter studenterna tyckerär viktiga och prioriterar att lägga tid på är också de aspekter som studenterna tycks hastörst förståelse och kunskap kring. / To get acquainted with other developers code can be difficult and time consuming. Codeconventions are developed in order to facilitate maintenance work for other developersworking on the same project, where the person who wrote the program rarely is the personthat maintains the same program. Little attention is paid to the aspect of quality ina projects development phase, which costs companies money and resources. This studyintends to investigate how students studying for a Bachelor of Science in Engineering inComputer Science at various universities in Sweden relate to Java code conventions, andif it is possible to discern a significant difference in code quality between these universitiesin terms of identifiers, comments, format and structure. An online survey was conductedwhose empirical data was analyzed using ANOVA, which is a recognized method forstatistical hypothesis testing. 21 of 23 ANOVA test showed that no significant differenceexisted between the institutions in terms of identifiers, comments and format and structure.The results also showed that the aspects of quality, which the students think are themost important, are also in fact the aspects they have the greatest understanding andknowledge about.

A utilização de produtos provenientes de fontes renováveis e livres de substâncias tóxicas é tendência global, prova disso é o constante aumento da demanda por produtos à base de madeira. Segundo o Forest Products Statistics (2015), a produção mundial de painéis de madeira reconstituída, em 2014, foi de 388 milhões de m³, um aumento de 5,5% em comparação com o ano anterior e um aumento de 34% quando comparado com 2010. No entanto, o setor industrial de painéis de madeira há décadas enfrenta um grande desafio com relação às emissões tóxicas vindas dos adesivos convencionais. Diante destes problemas, a proposta do presente trabalho foi testar a viabilidade da produção de painéis aglomerados e painéis OSB, com significativa redução da emissão de formaldeído, a partir de resíduos de madeira de Pinus sp. e Tectona grandis (Teca). Neste sentido, buscou-se contribuir para o aumento do conhecimento científico sobre a utilização do polímero natural polihidroxibutirato (PHB) e do resíduo de tinta à base de resina epóxi como adesivos alternativos. Os painéis foram fabricados variando-se os parâmetros de produção para obtenção de melhores condições de processo, sendo estes: densidade baixa, média e alta; teor de adesivo de 20, 30 e 40%; adição de partículas de Teca nas proporções de 0, 25, 50, 75, 100%. O desempenho físico-mecânico dos painéis foi avaliado com base nas normas ABNT NBR 14810 (2013) e ANSI A208.1 (2009). Realizou-se análise de variância (ANOVA) para testar a influência dos fatores individuais (densidade, percentual de adesivo e fração de Teca), além das interações entre tais fatores nas propriedades físico-mecânicas dos painéis. Os resultados apontaram para excelentes propriedades físicas e mecânicas dos painéis aglomerados de média e alta densidade, tendo resíduo de tinta, principalmente, nas proporções de 30 e 40%. Na maioria dos casos as propriedades de tais painéis foram superiores aos requisitos estipulados pela norma brasileira e pelas internacionais. Assim, ficou confirmada a viabilidade de produção dos aglomerados com pelo menos um dos insumos estudados bem como seu potencial de emprego para as finalidades compatíveis com produtos desta natureza. / The use of products from renewable sources and free of toxic substances is a global trend, the proof is the steady increase in demand for wood-based products. According to the Forest Products Statistics (2015), world production of reconstituted wood panels in 2014 was 388 million cubic meters, an increase of 5.5% compared to the previous year and an increase of 34% compared to 2010. However, the industrial sector of wood panels for decades faces a major challenge with regard to toxic emissions coming from conventional adhesives. Faced with these problems, the purpose of this study was to test the feasibility of production of panels and OSB panels, with significant reduction of formaldehyde emissions from wood waste Pinus sp. and teak (Teak). In this sense, we sought to contribute to the increase of scientific knowledge on the use of natural polymer polyhydroxybutyrate (PHB) and residual ink resin-based epoxy as alternative adhesives. The panels were manufactured by varying the production parameters to obtain the best processing conditions, namely: low density, medium and high; resin content of 20, 30 and 40%; adding particles of Teak in proportions of 0, 25, 50, 75, 100%. The physical-mechanical performance of the panels was evaluated based on the standards NBR 14810 (2013) and ANSI A208.1 (2009). Held analysis of variance (ANOVA) to test the influence of individual factors (density, adhesive percentage and fraction Teak), and the interactions among these factors in the physical-mechanical properties of the panels. The results showed excellent physical and mechanical properties of the panels average clusters and high density, and ink residue, mainly in the proportions of 30 and 40%. In most cases the properties of these boards were superior to the requirements set by the Brazilian and international standards. Thus, it was confirmed production of agglomerates with at least one viability of inputs studied as well as their potential for employment for purposes compatible with products of this nature.