Master's thesis is focused on implementing modern statistical methods for fitting propability distribution using kernel estimates with regard to the possibilities of their implementation on the PC and the application of specic data sets. Master's thesis is a part of project from MSMT of the Czech Republic no. 1M06047 Center for Quality and Reliability of Production.

The PERF tool is a part of the Linux kernel since version 2.6. This tool is an event-based profiler and observability tool. It can count various event occurrences in the system, from hardware performance monitoring unit (PMU) events of the CPU at one end, to software tracepoints at the other. It can trace both kernel and userspace functions. The tool is very useful to kernel and application software developers, as well as hardware designers. This thesis aims at describing the PERF tool from the point of view of a PERF test engineer. Additionally, it is also about designing methods for verification of its correct functionality.

No description available.

Atualmente, a caracterização dos resíduos radioativos gerados na operação do reator nuclear de pesquisas IEA-R1 está em curso. O reator IEA-R1 é um reator do tipo piscina aberta, moderado e refrigerado por água leve, utilizando dois leitos de resinas de troca iônica e de carvão ativado para purificação de água de refrigeração. Estes meios filtrantes são substituídos quando já não são capazes de manter a qualidade da água dentro dos limites exigidos e são tratados como rejeitos radioativos. Contendo produtos de fissão, ativação e actinídeos que escapam do núcleo do reator para a água da piscina, apresentam altas taxas de dose devido à quantidade de emissores gama de meias-vidas curtas e intermediárias, emissores alfa, elementos transurânicos de meia-vida longa bem como emissores beta puros. A caracterização destes rejeitos, consequentemente, requer métodos de análise radioquímica que incluem a amostragem e o processamento das amostras, resultando em doses elevadas para os trabalhadores. Nesse contexto, o objetivo deste trabalho consistiu em correlacionar os resultados das análises radioquímicas de amostras de rejeitos, com os resultados das medições radiométricas, utilizando a modelagem das taxas de dose em diferentes distâncias da superfície dos embalados. As taxas de dose medidas foram comparadas com os resultados de cálculos . Massa, volume e geometria das fases sólidas e líquidas de cada um dos tambores também foram determinadas, uma vez que o teor de água varia amplamente entre diferentes tambores, e são essenciais para estimar as atividades totais em cada tambor. / The characterization of the radioactive wastes generated in the operation of the nuclear research reactor IEA-R1 is currently ongoing. The IEA-R1 is an open pool type reactor, moderated and cooled by light water that uses two beds of ion-exchange resins and activated charcoal to remove impurities from the cooling water. These filter media are replaced when they are no longer able to maintain water quality within the required limits and are treated as radioactive waste. They contain the actinides and the fission and activation products that leaked into the reactor pool water. They give off high dose rates due to the amount of gamma-emitters present and are a long-term radiation safety concern because of their content of long-lived alpha- and beta-emitters. The characterization of these wastes requires radiochemical analysis methods, which include the sampling and processing of samples, resulting in high exposure to the workers. The objective of this study was to correlate the results of activity concentrations obtained in previous radiochemical analyses with the results of measurements of dose rates at various distances from the package surfaces, aiming at reducing the exposure of personnel by avoiding more sampling and sample analysis operations. Mass, volume and geometry of solid and liquid phases of each drum, which vary widely among different drums, were also estimated and use to determine total activity. The measured and calculated dose rates were compared to confirm the activity estimates.

Este trabalho tem como objetivo propor e desenvolver uma plataforma para ensino e treinamento em técnicas de projeto e implementação de sistemas operacionais. Após mais de uma década de hegemonia de alguns poucos produtos comerciais, o estabelecimento do paradigma do software livre e a proliferação de arquiteturas embarcadas capazes de executar um sistema operacional (SO) implicam em demanda de especialistas para atuarem diretamente no desenvolvimento de novos SOs, adequados a novos requisitos das aplicações emergentes. Assim, para além de disciplina de formação teórica, o conhecimento em sistemas operacionais tem reforçado seu caráter prático como competência técnica perspectiva que este trabalho atende mediante uma abordagem de aprendizado baseado em projetos. A principal contribuição para o estado da arte nesse domínio é um roteiro de instrução que associa teoria e prática por meio do processo de desenvolvimento integral de um sistema operacional funcional / This work aims at proposing and developing a learning and training platform on design and implementation of operating systems. After more than a decade of hegemony of a few commercial products, the establishment of free software paradigm and the proliferation of embedded architectures capable of running an operating system (OS) increase the demand for specialists to work directly on the development of new operating systems suited to the new requirements of novel applications. Therefore, beyond its function as theoretical background discipline, the area of operating systems has its practical importance highlighted as a technical competence a perspective which this work meets by means of a project-based learning approach. The main contribution to the state of the art in this domain is an instruction program which associates theory and practice through the process of developing integrally a functional operating system

Atualmente, a caracterização dos resíduos radioativos gerados na operação do reator nuclear de pesquisas IEA-R1 está em curso. O reator IEA-R1 é um reator do tipo piscina aberta, moderado e refrigerado por água leve, utilizando dois leitos de resinas de troca iônica e de carvão ativado para purificação de água de refrigeração. Estes meios filtrantes são substituídos quando já não são capazes de manter a qualidade da água dentro dos limites exigidos e são tratados como rejeitos radioativos. Contendo produtos de fissão, ativação e actinídeos que escapam do núcleo do reator para a água da piscina, apresentam altas taxas de dose devido à quantidade de emissores gama de meias-vidas curtas e intermediárias, emissores alfa, elementos transurânicos de meia-vida longa bem como emissores beta puros. A caracterização destes rejeitos, consequentemente, requer métodos de análise radioquímica que incluem a amostragem e o processamento das amostras, resultando em doses elevadas para os trabalhadores. Nesse contexto, o objetivo deste trabalho consistiu em correlacionar os resultados das análises radioquímicas de amostras de rejeitos, com os resultados das medições radiométricas, utilizando a modelagem das taxas de dose em diferentes distâncias da superfície dos embalados. As taxas de dose medidas foram comparadas com os resultados de cálculos . Massa, volume e geometria das fases sólidas e líquidas de cada um dos tambores também foram determinadas, uma vez que o teor de água varia amplamente entre diferentes tambores, e são essenciais para estimar as atividades totais em cada tambor. / The characterization of the radioactive wastes generated in the operation of the nuclear research reactor IEA-R1 is currently ongoing. The IEA-R1 is an open pool type reactor, moderated and cooled by light water that uses two beds of ion-exchange resins and activated charcoal to remove impurities from the cooling water. These filter media are replaced when they are no longer able to maintain water quality within the required limits and are treated as radioactive waste. They contain the actinides and the fission and activation products that leaked into the reactor pool water. They give off high dose rates due to the amount of gamma-emitters present and are a long-term radiation safety concern because of their content of long-lived alpha- and beta-emitters. The characterization of these wastes requires radiochemical analysis methods, which include the sampling and processing of samples, resulting in high exposure to the workers. The objective of this study was to correlate the results of activity concentrations obtained in previous radiochemical analyses with the results of measurements of dose rates at various distances from the package surfaces, aiming at reducing the exposure of personnel by avoiding more sampling and sample analysis operations. Mass, volume and geometry of solid and liquid phases of each drum, which vary widely among different drums, were also estimated and use to determine total activity. The measured and calculated dose rates were compared to confirm the activity estimates.

Este trabalho tem como objetivo propor e desenvolver uma plataforma para ensino e treinamento em técnicas de projeto e implementação de sistemas operacionais. Após mais de uma década de hegemonia de alguns poucos produtos comerciais, o estabelecimento do paradigma do software livre e a proliferação de arquiteturas embarcadas capazes de executar um sistema operacional (SO) implicam em demanda de especialistas para atuarem diretamente no desenvolvimento de novos SOs, adequados a novos requisitos das aplicações emergentes. Assim, para além de disciplina de formação teórica, o conhecimento em sistemas operacionais tem reforçado seu caráter prático como competência técnica perspectiva que este trabalho atende mediante uma abordagem de aprendizado baseado em projetos. A principal contribuição para o estado da arte nesse domínio é um roteiro de instrução que associa teoria e prática por meio do processo de desenvolvimento integral de um sistema operacional funcional / This work aims at proposing and developing a learning and training platform on design and implementation of operating systems. After more than a decade of hegemony of a few commercial products, the establishment of free software paradigm and the proliferation of embedded architectures capable of running an operating system (OS) increase the demand for specialists to work directly on the development of new operating systems suited to the new requirements of novel applications. Therefore, beyond its function as theoretical background discipline, the area of operating systems has its practical importance highlighted as a technical competence a perspective which this work meets by means of a project-based learning approach. The main contribution to the state of the art in this domain is an instruction program which associates theory and practice through the process of developing integrally a functional operating system

Both complex dynamics and the theory of reproducing kernel Hilbert spaces have found widespread application over the last few decades. Although complex dynamics started over a century ago, the gravity of it's importance was only recently realized due to B.B. Mandelbrot's work in the 1980's. B.B. Mandelbrot demonstrated to the world that fractals, which are chaotic patterns containing a high degree of self-similarity, often times serve as better models to nature than conventional smooth models. The theory of reproducing kernel Hilbert spaces also having started over a century ago, didn't pick up until N. Aronszajn's classic was written in 1950. Since then, the theory has found widespread application to fields including machine learning, quantum mechanics, and harmonic analysis. In the paper, Infinite Product Representations of Kernel Functions and Iterated Function Systems, the authors, D. Alpay, P. Jorgensen, I. Lewkowicz, and I. Martiziano, show how a kernel function can be constructed on an attracting set of an iterated function system. Furthermore, they show that when certain conditions are met, one can construct an orthonormal basis of the associated Hilbert space via certain pull-back and multiplier operators. In this thesis we take for our iterated function system, the family of iterates of a given rational map. Thus we investigate for which rational maps their kernel construction holds as well as their orthornormal basis construction. We are able to show that the kernel construction applies to any rational map conjugate to a polynomial with an attracting fixed point at 0. Within such rational maps, we are able to find a family of polynomials for which the orthonormal basis construction holds. It is then natural to ask how the orthonormal basis changes as the polynomial within a given family varies. We are able to determine for certain families of polynomials, that the dynamics of the corresponding orthonormal basis is well behaved. Finally, we conclude with some possible avenues of future investigation.

To meet different requirements for different stakeholders, branches are widely used to maintain multiple product variants simultaneously. For example, Linux Kernel has a main development branch, known as the mainline; 35 branches to maintain older product versions which are called stable branches; and hundreds of branches for experimental features. To maintain multiple branch-based product variants in parallel, developers often port new features or bug-fixes from one branch to another. In particular, the process of propagating bug-fixes or feature additions to an older version is commonly called backporting. Prior to our study, backporting practices in large scale projects have not been systematically studied. This lack of empirical knowledge makes it difficult to improve the current backporting process in the industry. We hypothesized that cross-branch porting practice is frequent, repetitive, and error-prone. It required significant effort for developers to select patches that need to be backported and then apply them to the target implementation. We carried out two complementary studies to examine this hypothesis. To investigate the extent and effort of porting practice, this thesis first conducted a quantitative study of backporting activities in Linux Kernel with a total of 8 years version history using the data of the main branch and the 35 stable branches. Our study showed that backporting happened at a rate of 149 changes per month, and it took 51 days to propagate patches on average. 40% of changes in the stable branches were ported from the mainline and 64% of ported patches propagated to more than one branch. Out of all backporting changes from the mainline to stable branches, 97.5% were applied without any manual modifications. To understand how Linux Kernel developers keep up to date with development activities across different branches, we carried out an online survey with engineers who may have ported code from the mainline to stable branches based on our prior analysis of Linux Kernel version history. We received 14 complete responses. The participants have 12.6 years of Linux development experience on average and are either maintainers or experts of Linux Kernel. The survey showed that most backporting work was done by the maintainers who knew the program quite well. Those experienced maintainers could easily identify the edits that need to be ported and propagate them with all relevant changes to ensure consistency in multiple branches. Inexperience developers were seldom given an opportunity to backport features or bug-fixes to stable branches. In summary, based on the version history study and the online survey, we concluded that cross-branch porting is frequent, periodic, and repetitive. It required a manual effort to selectively identify the changes that need to be ported, to analyze the dependency of the selected changes, and to apply all required changes to ensure consistency. To eliminate human's omission mistakes, most backporting work was done only by experienced maintainers who could identify all relevant changes along with the change that needed to be backported. Currently inexperienced developers were excluded from cross-branch porting activities from the mainline to stable branches in Linux Kernel. Our results call for an automated approach to identify the patches that require to be ported, to collect context information to help developers become aware of relevant changes, and to notify pertinent developers who may be responsible for the corresponding porting events. / text

My dissertation includes three essays that examine or relax classical restrictive assumptions used in econometrics estimation methods. The first chapter proposes methods for examining how a response variable is influenced by a covariate. Rather than focusing on the conditional mean I consider a test of whether a covariate has an effect on the entire conditional distribution of the response variable given the covariate and other conditioning variables. This type of analysis is useful in situations where the econometrician or policy maker is interested in knowing whether a variable or policy would improve the distribution of the response outcomes in a stochastic dominance sense. The response variable is assumed to be continuous, while both discrete and continuous covariate cases are considered. I derive the asymptotic distribution of the test statistics and show that they have simple known asymptotic distributions under the null by using and extending conditional empirical process results given by Horvath and Yandell (1988). Monte Carlo experiments are conducted, and the tests are shown to have good small sample behavior. The tests are applied to a study on father's labor supply. The second chapter is based on previous joint work with Jason Abrevaya. It considers estimation of censored panel-data models with individual-specific slope heterogeneity. The slope heterogeneity may be random (random-slopes model) or related to covariates (correlated-random-slopes model). Maximum likelihood and censored least-absolute deviations estimators are proposed for both models. Specification tests are provided to test the slope-heterogeneity models against nested alternatives. The proposed estimators and tests are used for an empirical study of Dutch household portfolio choice. Strong evidence of correlated random slopes for the age variables is found, indicating that the age profile of portfolio adjustment varies significantly with other household characteristics. The third chapter proposes specification tests in models with endogenous covariates. In empirical studies, econometricians often have little information on the functional form of the structural model, regardless of whether covariates in model are exogenous or endogenous. In this chapter, I propose tests for restricted structural model specifications with endogenous covariates against the fully nonparametric alternative. The restricted model specifications include the nonparametric specification with a restricted set of covariates, the semiparametric single index specification and the parametric linear specification. Test statistics are “leave-one-out” type kernel U-statistic as used in Fan and Lee (1996). They are constructed using the idea of the control function approach. Monte Carlo results are provided and tests are shown to have reasonable small sample behavior. / text