A crescente demanda por biocombustíveis e a concorrência dos combustíveis fósseis torna necessária a otimização dos meios já existentes e o desenvolvimento de novas tecnologias para produção de biocombustíveis, principalmente em projetos envolvendo biorreatores e fotobiorreatores (FBR) industriais. A dinâmica dos fluidos computacional (CFD) vem sendo utilizada em vários trabalhos para o estudo de parâmetros fluidodinâmicos que podem influenciar no rendimento dos processos químicos envolvidos, como tensão de cisalhamento, perfis de velocidade, tempo de residência e a influência da geometria sobre esses parâmetros. Contudo, não existe ainda um número abrangente de trabalhos que utilize técnicas de otimização acopladas com a resolução numérica do problema fluidodinâmico. Em alguns estudos, algoritmos de otimização são utilizados para determinar os melhores coeficientes das reações químicas. No entanto, não há estudos, até o momento, que reportem a otimização multiobjetivo simultânea dos parâmetros geométricos e do escoamento aplicados a equipamentos da indústria sucro-energética. Neste contexto, o presente trabalho de pesquisa tem como objetivo contribuir para o avanço científico e tecnológico através da implementação de um software aberto (PyCFD-O) que permita o acoplamento CFD-otimização e o desenvolvimento das bases de uma metodologia de projeto otimizado bem como de operação de biorreatores e FBRs de escala industrial. O PyCFD-O foi testado em dois estudos de caso que podem ser estendidos a um fermentador contínuo e um FBR. Os parâmetros geométricos de ambos os reatores foram otimizados de forma a minimizar simultaneamente a tensão de cisalhamento e a variância da distribuição do tempo de residência. O software PyCFD-O mostrou-se robusto, revelando que o processo global de otimização realiza de fato a busca pela fronteira de Pareto. Além da obtenção das geometrias otimizadas, também foram discutidos a influência dos parâmetros geométricos na hidrodinâmica do escoamento em ambos os casos. / The growing demand for biofuels and its competition with fossil fuels create the need to optimize the existing resources and development of new technologies for production of biofuels, particularly in projects involving industrial bioreactors and photobioreactors (PBR). Computational fluid dynamics (CFD) has been used in several studies for the study of fluid dynamics parameters that can influence the performance of the chemical process involved, such as shear stress, velocity profiles, residence time and the influence of these parameters on the reactor geometry. However, there are lacks of studies that utilize optimization techniques coupled with the numerical resolution of the fluid dynamic problem. The use of optimization algorithms has been reported in some cases, but there have not been reports on studies combining the optimization of flow parameters and multiobjective algorithms to choose ideal geometric parameters applied to the equipment of the sugar-energy industry. In this context, this research project aims to contribute to the advancement of scientific and technological knowledge trhough the implementation of open source software (PyCFD-O) for the CFD-optimization coupling and the development of the bases of a methodology for optimal design and operation of industrial scale bioreactors and PBR. The PyCFD-O software was tested in two case studies with characteristics that can be extended to a continuos fermenter and PBR. The geometric parameters of both reactors were simultaneously optimized in order to minimize the shear stress and the variance of residence time distribuition. The PyCFD-O software showed robustness, revealing that overall optimization process actually performs the search of Pareto frontier. In addition to the geometry optimization, the influence of the geometrical parameters of the hydrodynamic of the flow was discussed in both case studies.

We address the task of mapping a given domain model (e.g., an industry-standard reference model) for a given domain (e.g., ERP), with the source code of an independently developed application in the same domain. This has applications in improving the understandability of an existing application, migrating it to a more flexible architecture, or integrating it with other related applications. We build on a previous approach, which uses relationships among source code elements for improving the precision of the mapping process. We extend this approach by considering relationships among domain model elements in addition to relationships among source code elements, and also by stating the mapping process as an optimization problem. We have implemented our approach, and compared it with the previous approach. We show that our approach gives significantly better precision as well as recall than the previous approach when applied on a real industry-standard domain model and an open-source application.

This thesis deals with the development environment for generating client/server database applications. The thesis defines the characteristics of good architecture of database applications and proposes appropriate concepts for the unification of system parts of the application. It also analyzes the characteristics of the development environment to facilitate the implementation of database applications. In thesis is proposed data model. There is implemented a prototype of development enviroment and verified its functionality and correctness of the proposed concepts.

This master's thesis describes the design and implementation of optimizations in the middle-end part of a retargetable decompiler developed by AVG Technologies. The purpose of these optimizations is to improve readability of the produced source code and improve existing optimizations in the back-end part. In the introduction, basic information about reverse engineering and decompilation is provided. Then, a description of state of the retargetable decompiler before this work is given. After that, the main part of this work is presented, which describes the design and implementation of the proposed optimizations. Then, the techniques that were used for testing are described. This description is followed by a summary of the achieved results. The present work is concluded by a discussion of possible future development.

The purpose of this thesis is to design and implement tools for support of a snapshot and a rollback for configuration files on the GNU/Linux distribution. The set of the tools enables an automatic/periodical saving of the configuration files into the selected placement. The creation of backups reacts to file events by watching the changes with kernel subsystem inotify. Tools are enabling to return to the selected backup. The way of the backup actualization is configurable. This tool permits the data comparison from selected backups, to show the differences in configurations and eventually to manage a merge among actual and selected backup. Tools also allows a comparison of a configurations of one client or configurations among clients, and to display the mutual differences, eventually to manage their merge.

The world is becoming more and more digitized which in turn puts pressure on existing applications and systems to be able to handle large quantities of data. And  in some cases, that data also needs to be operated in secure and isolated environments. To address these needs, a new category  of databases has emerged, by the name of NewSQL. The downside of this new category is that it still remains unexplored in some areas, such as how each database under that category performs towards each other, or even towards databases belonging to other categories. One major aspect, in terms of performance is latency, since it affects the overall user-experience. In order to clear up some of the unexplored areas within NewSQL, two databases were studied in the context of their latency performance: CockroachDB and Vitess. The study was divided into two main parts. The first one, was a quantitative study, which was about gathering data on how each database performed in terms of latency when serving the create, read, update, and delete-operations. No clear differences in latency were found for the create- and read-operations. While the results for update- and delete-operations showed significant differences where Vitess had lower latency than CockroachDB.  The second part of this study was a qualitative study, dedicated to analyze and inspect each database architecture and source code. The intention was to identify potential factors that may affect latency performance. The outcome from the analysis was that three main factors could be identified. The first identified factor is that CockroachDB had a layered architecture and that it needed to translate SQL queries into a set of key-value operations. The second one is that the databases makes use of different storage engines, which in turn can have differences in performance. The third and final identified factor is that MySQL, which was integrated with Vitess, had existed for a longer period of time compared to CockroachDB. Which indicates that the database probably has been more optimized over the years.

In today’s digital landscape, maintaining the integrity of source code is crucial for delivering reliable and trustworthy software solutions. However, the increasing prevalence of attacks targeting source code repositories and version control systems (VCSs) poses significant challenges to source code integrity. Unauthorized access to source code repositories can lead to various security risks, including the introduction of malicious code or unauthorized approvals for pull requests. Security measures implemented on the remote server hosting the repository are typically insufficient to detect these types of attacks, resulting in changes potentially remaining undetected and becoming part of the deployed artifact. To address those issues, this study proposes GitBark, a framework that employs cryptographic methods to verify the integrity of a source code repository. GitBark achieves this by enforcing rules and policies on the commits made to the repository. Specifically, the study demonstrates that by formulating rules that utilize digital signatures, GitBark can effectively identify unauthorized changes and approvals. Moreover, GitBark prioritizes maintaining the local repository in a consistent and trustworthy state, reducing reliance on the remote server. Even if changes violating established rules are introduced to the remote repository, GitBark prevents their integration into the local repository. Consequently, users of GitBark can have confidence that their local repository remains a consistent and trustworthy version of the source code, without needing to place full trust on a remote server. An evaluation of GitBark, along with the devised rules, demonstrates its effectiveness in mitigating the threats identified in this study. Additionally, in terms of performance, GitBark incurs a modest overhead, both in time and storage. / I dagens digital värld, så är det viktigare än någonsin att källkodens integritet upprätthålls. Detta är kritiskt för att kunna leverera tillförlitlig och kvalitativ mjukvara. Den ständigt ökade förekomsten av attacker som riktar sig mot källkodsrepon och versionshanteringssystem gör dock upprätthållandet av källkodens integritet svårt. Obehörig åtkomst till källkodsrepo ger upphov till flera säkerhetsrisker såsom inkluderandet av skadlig kod eller obehöriga godkännanden av nya ändringar. De säkerhetsåtgärder som finns implementerade på värdserven där källkodsrepot lagras kan generellt sätt inte detektera dessa typer av attacker, vilket resulterar i att dessa typer av ändringar oftast förblir oupptäckta. För att adressera dessa problem, så presenterar denna studie GitBark, ett verktyg som utnyttjar kryptografiska medel för att verifiera integriteten av ett källkodsrepo. GitBark gör detta genom att kräva regler för commits som görs till källkodsrepot och validera att de upprätthålls. Mer specifikt, så visar att studien att genom att formulera regler som uttnyttjar digitala signaturer så kan GitBark effektivt identifiera oauktoriserade ändringar och godkännanden. Dessutom, prioriterar GitBark att alltid bibehålla det lokala källkodsrepot i ett konsekvent och trovärdigt tillstånd, för att minska beroendet på en remoteserver. Även ifall ändringar som inte uppfyller reglerna introduceras på remote-källkodsrepot så ser GitBark till att dessa ändringar aldrig integreras i det lokala repot. Följaktligen så kan användare av GitBark känna sig säkra i att det lokala källkodsrepot alltid förblir i ett konsekvent och trovärdigt tillstånd i relation till dem etablerade reglerna, utan att behöva förlita sig på en remoteserver. En evaluering av GitBark, tillsammans med de skapade reglerna påvisar dess effektivitet i att adressera de identifierade hoten i denna studie. Dessutom, vad gäller prestanda så har GitBark en liten påverkan både i tid och utrymme.

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