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.

The teaching and learning process of computer programming is a complex task which requires a lot of practice and creativity. Usually, there are numerous solutions to the same problem. Therefore, the student needs that his solutions are evaluated quickly for a faster and effective learning. To face these challenges, teachers and students can rely on resources from the evolution of Information and Communication Technology. Virtual learning environments and online judge systems are attractive alternatives used in this context. This work presents a unified approach to specify and check source code restrictions supported by a static analyzer. Although current tools are able to indicate if the program produced the expected output from a given input, not all are able to determine if the student used (or not) a given programming language construct, such as creating a function and using it in the program. Among those that are capable, there are problems that were solved in the approach proposed in this work, such as: ease of use, unified approach and degree of flexibility. In addition, this work presents an analysis of the database of The Huxley with the purpose of discovering the main restrictions of source code used by the teachers and attended by the students. This analysis was done based on data obtained from the use of the developed static analyzer and in conjunction with a survey applied to the teachers of introduction to programming with the purpose of knowing the main restrictions that would be used by them if they had a tool to specify and check restrictions. / O processo de ensino e aprendizagem da programação de computadores é uma tarefa complexa que requer bastante prática e criatividade. Geralmente há inúmeras soluções para um mesmo problema. Por isso, o aluno precisa que suas soluções sejam avaliadas rapidamente visando um aprendizado mais ágil e eficaz. Para enfrentar esses desafios, os professores e alunos podem contar com recursos provenientes da evolução da Tecnologia da Informação e Comunicação. Os ambientes de aprendizagem virtual e os sistemas de juiz on-line são alternativas atrativas utilizadas nesse contexto. Este trabalho apresenta uma abordagem unificada de especificação e checagem de restrições de código-fonte apoiada por um analisador estático. Apesar das ferramentas atuais serem capazes de indicar se o programa produziu a saída esperada a partir de uma entrada fornecida, nem todas são capazes de determinar se o aluno utilizou (ou não) determinada construção de linguagem de programação, como por exemplo criar uma função e utilizá-la no programa. Entre as que são capazes, existem problemas que foram sanados na abordagem proposta neste trabalho, como: facilidade de uso, abordagem unificada e grau de flexibilidade. Além disto, este trabalho conta com uma análise da base de dados do The Huxley com o objetivo de descobrir quais são as principais restrições de código-fonte utilizadas pelos professores e atendidas pelos alunos. Esta análise foi feita com os dados obtidos da aplicação do analisador estático de código-fonte desenvolvido e em conjunto com um survey aplicado aos professores de introdução à programação com o propósito de conhecer as principais restrições que seriam utilizadas por eles se possuíssem uma ferramenta de especificação e checagem de restrições. / São Cristóvão, SE

<p>This dissertation proposes an approach to reduce the cost of manual inspections for as large a number of false positive warnings that are being reported by Static Code Analysis (SCA) tools as much as possible using Machine Learning (ML) techniques. The proposed approach neither assume to use the particular SCA tools nor depends on the specific programming language used to write the target source code or the application. To reduce the number of false positive warnings we first evaluated a number of SCA tools in terms of software engineering metrics using a highlighted synthetic source code named the Juliet test suite. From this evaluation, we concluded that the SCA tools report plenty of false positive warnings that need a manual inspection. Then we generated a number of datasets from the source code that forced the SCA tool to generate either true positive, false positive, or false negative warnings. The datasets, then, were used to train four of ML classifiers in order to classify the collected warnings from the synthetic source code. From the experimental results of the ML classifiers, we observed that the classifier that built using the Random Forests</p> <p>(RF) technique outperformed the rest of the classifiers. Lastly, using this classifier and an instance-based transfer learning technique, we ranked a number of warnings that were aggregated from various open-source software projects. The experimental results show that the proposed approach to reduce the cost of the manual inspection of the false positive warnings outperformed the random ranking algorithm and was highly correlated with the ranked list that the optimal ranking algorithm generated.</p>

Cars, trains, trucks, telecom networks and industrial robots are examples of products relying on complex embedded software systems, running on embedded computers. Such systems may consist of millions of lines of program code developed by hundreds of engineers over many years, often decades. Over the long life-cycle of such systems, the main part of the product development costs is typically not the initial development, but the software maintenance, i.e., improvements and corrections of defects, over the years. Of the maintenance costs, a major cost is the verification of the system after changes has been applied, which often requires a huge amount of testing. However, today's techniques are not sufficient, as defects often are found post-release, by the customers. This area is therefore of high relevance for industry. Complex embedded systems often control machinery where timing is crucial for accuracy and safety. Such systems therefore have important requirements on timing, such as maximum response times. However, when maintaining complex embedded software systems, it is difficult to predict how changes may impact the system's run-time behavior and timing, e.g., response times.Analytical and formal methods for timing analysis exist, but are often hard to apply in practice on complex embedded systems, for several reasons. As a result, the industrial practice in deciding the suitability of a proposed change, with respect to its run-time impact, is to rely on the subjective judgment of experienced developers and architects. This is a risky and inefficient, trial-and-error approach, which may waste large amounts of person-hours on implementing unsuitable software designs, with potential timing- or performance problems. This can generally not be detected at all until late stages of testing, when the updated software system can be tested on system level, under realistic conditions. Even then, it is easy to miss such problems. If products are released containing software with latent timing errors, it may cause huge costs, such as car recalls, or even accidents. Even when such problems are found using testing, they necessitate design changes late in the development project, which cause delays and increases the costs. This thesis presents an approach for impact analysis with respect to run-time behavior such as timing and performance for complex embedded systems. The impact analysis is performed through optimizing simulation, where the simulation models are automatically generated from the system implementation. This approach allows for predicting the consequences of proposed designs, for new or modified features, by prototyping the change in the simulation model on a high level of abstraction, e.g., by increasing the execution time for a particular task. Thereby, designs leading to timing-, performance-, or resource usage problems can be identified early, before implementation, and a late redesigns are thereby avoided, which improves development efficiency and predictability, as well as software quality. The contributions presented in this thesis is within four areas related to simulation-based analysis of complex embedded systems: (1) simulation and simulation optimization techniques, (2) automated model extraction of simulation models from source code, (3) methods for validation of such simulation models and (4) run-time recording techniques for model extraction, impact analysis and model validation purposes. Several tools has been developed during this work, of which two are in commercialization in the spin-off company Percepio AB. Note that the Katana approach, in area (2), is subject for a recent patent application - patent pending. / PROGRESS

A new method for making software is stealthily gaining ground in the computer industry, offering a promise of better, cheaper software and the empowerment of the user. The open source movement could revolutionize the software industry...if it succeeds. Open source means software that you are allowed to copy, modify, and give to friends. Source code , the lists of instructions which tell computers how to run, is readily available, allowing you to look inside the workings of a program and change it to suit your needs. A group of programmers, companies, users, and activists have gathered in support of this empowering technology, seeking to persuade businesses and users that open source is the way to go. However, open source faces stiff challenges. The economic basis for the software industry is to charge users by the copy when they buy software. Copying and modification are illegal. The industry and its customers are so mired in this worldview that the idea of giving out a program's "recipe," along with a license to change or copy it at will, seems preposterous. Powerful players in the software industry, such as Microsoft, see open source as a threat to their bottom line, and have devoted their energies to discrediting and marginalizing the movement. Beginning from the assumption that cheap, reliable software that empowers the user is a good thing, this thesis looks at the claims made by advocates about the benefits of open source. I explore how the advocates make their case to the business world, the public, and government. I also look at ways in which the government could help bring about an open source revolution, using the policy tools of procurement, research funding, standards enforcement, and antitrust law. I conclude that programmers and public interest lobbyists must join forces to carry this revolution forward, and that the time for action is now, while Microsoft is on trial.

Power consumption is gradually becoming an important issue of designing computing systems. Most of the researches of low power issues have focused on semiconductor techniques or hardware architecture designs, but less utilized the techniques of software optimization. This paper presents a new scheduling methodology in source code level for Intelligent Memory System, which reduces the energy consumption by means of code compilation techniques. The scheduling kernel provides two options for users: performance-oriented low power scheduling and energy-oriented low power scheduling, to achieve the objective of considering high performance and low power issues. The experimental results are also presented and discussed.

Wireless multimedia sensor networks (WMSNs) are networks of interconnected devices that allow retrieving video and audio streams, still images, and scalar data from the environment. In a densely deployed WMSN, there exists correlation among the observations of camera sensors with overlapped coverage areas, which introduces substantial data redundancy in the network. In this dissertation, efficient communication schemes are designed for WMSNs by leveraging the correlation of visual information observed by camera sensors. First, a spatial correlation model is developed to estimate the correlation of visual information and the joint entropy of multiple correlated camera sensors. The compression performance of correlated visual information is then studied. An entropy-based divergence measure is proposed to predict the compression efficiency of performing joint coding on the images from correlated cameras. Based on the predicted compression efficiency, a clustered coding technique is proposed that maximizes the overall compression gain of the visual information gathered in WMSNs. The correlation of visual information is then utilized to design a network scheduling scheme to maximize the lifetime of WMSNs. Furthermore, as many WMSN applications require QoS support, a correlation-aware QoS routing algorithm is introduced that can efficiently deliver visual information under QoS constraints. Evaluation results show that, by utilizing the correlation of visual information in the communication process, the energy efficiency and networking performance of WMSNs could be improved significantly.

Šiame dokumente aprašytas darbas susideda ir trijų pagrindinių dalių. Pirmojoje, inžinerinėje dalyje atlikome vizitų registravimo sistemos (toliau - „PharmaCODE“) analizę ir projektavimą. Čia pateikėme esmines verslo aplinkos, reikalavimų ir konkurentų analizės, o taipogi ir projektavimo detales. Pateikėme pagrindinius architektūrinius sprendimus. Antrojoje darbo dalyje aprašėme sistemos kokybės tyrimus, naudojant statinės išeities kodų analizės įrankius ir metodus. Šioje dalyje aprašėme kokius įrankius naudojome ir pateikėme pagrindinius kodo analizės rezultatus. Trečiojoje darbo dalyje gilinomės į išeities tekstų analizės metodus ir įrankius, sukūrėme patobulintą analizės taisyklę. Mūsų taisyklės pagalba pavyko aptikti daugiau potencialių SQL-įterpinių saugumo spragų nei aptiko jos pirmtakė – Microsoft projektuota kodo analizės taisyklė. / This work consists of three major parts. First – engineering part – is analysis and design of call reporting system (codename – “PharmaCODE”). We will provide main details of business analysis and design decisions. Second part is all about testing and ensuring system quality, mainly by means of static source code analysis tools & methods. We will describe tools being used and provide main results of source code analysis in this part. And finally, in the third part of this we go deeper into static source code analysis and try to improve one of analysis rules. These days, when there is plenty of evolving web-based applications, security is gaining more and more impact. Most of those systems have, and depend on, back-end databases. However, web-based applications are vulnerable to SQL-injection attacks. In this paper we present technique of solving this problem using secure-coding guidelines and .NET Framework’s static code analysis methods for enforcing those guidelines. This approach lets developers discover vulnerabilities in their code early in development process. We provide a research and realization of improved code analysis rule, which can automatically discover SQL-injection vulnerabilities in MSIL code.

Dans le développement logiciel en industrie, les documents de spécification jouent un rôle important pour la communication entre les analystes et les développeurs. Cependant, avec le temps, les changements de personel et les échéances toujours plus courtes, ces documents sont souvent obsolètes ou incohérents avec l'état effectif du système, i.e., son code source. Pourtant, il est nécessaire que les composants du système logiciel soient conservés à jour et cohérents avec leurs documents de spécifications pour faciliter leur développement et maintenance et, ainsi, pour en réduire les coûts. Maintenir la cohérence entre spécification et code source nécessite de pouvoir représenter les changements sur les uns et les autres et de pouvoir appliquer ces changements de manière cohérente et automatique. Nous proposons une solution permettant de décrire une représentation d'un logiciel ainsi qu'un formalisme mathématique permettant de décrire et de manipuler l'évolution des composants de ces représentations. Le formalisme est basé sur les triplets de Hoare pour représenter les transformations et sur la théorie des groupes et des homomorphismes de groupes pour manipuler ces transformations et permettrent leur application sur les différentes représentations du système. Nous illustrons notre formalisme sur deux représentations d'un système logiciel : PADL, une représentation architecturale de haut niveau (semblable à UML), et JCT, un arbre de syntaxe abstrait basé sur Java. Nous définissons également des transformations représentant l'évolution de ces représentations et la transposition permettant de reporter les transformations d'une représentation sur l'autre. Enfin, nous avons développé et décrivons brièvement une implémentation de notre illustration, un plugiciel pour l'IDE Eclipse détectant les transformations effectuées sur le code par les développeurs et un générateur de code pour l'intégration de nouvelles représentations dans l'implémentation. / When developing software system in industry, system specifications are heavily used in communication among analysts and developers. However, system evolution, employee turn-over and shorter deadlines lead those documents either not to be up-to-date or not to be consistent with the actual system source code. Yet, having up-to-date documents would greatly help analysts and developers and reduce development and maintenance costs. Therefore, we need to keep those documents up-to-date and consistent. We propose a novel mathematical formalism to describe and manipulate the evolution of these documents. The mathematical formalism is based on Hoare triple to represent the transformations and group theory and groups homomorphisms to manipulate these transformations and apply them on different representations. We illustrate our formalism using two representation of a same system: PADL, that is an abstract design specification (similar to UML), and JCT, that is an Abstract Syntax Tree for Java. We also define transformations describing their evolutions, and transformations transposition from one representation to another. Finally, we provide an implementation of our illustration, a plugin for the Eclipse IDE detecting source code transformations made by a developer and a source code generator for integrating new representations in the implementation.

Plagiarism among students of introductory programming courses has been increasing over time. The ease of exchange of information brought by the Internet can be the factor responsible for this increase. In many cases, students try to disguise the plagiarism making some modifications to the source code. However, some masking techniques are extremely complex to be detected and may not be seen with the naked eye. In this dissertation, detection techniques were analyzed and, on this basis, was developed a system able to detect plagiarism in source code. This system is based on the representation code as an abstract syntax tree and Karp-Rabin Greedy String Tiling algorithm. The system was evaluated using a source-code base of students of programming disciplines. Oracle based comparison was performed to compare the system with others. The oracle was created from the manual analysis of the teacher of the subject, which was marked if there was plagiarism or not in each pair of source code. To represent the results, ROC curves and confusion matrices were used. The same procedure was applied to existing systems, allowing direct comparison of results. More specifically, we use the value of the area under the curve and the minimum distance to point (0, 1) of the ROC space, since these figures represent the classification performance. The analysis of results shows that, for the sample used, the developed system obtained higher area under the curve and also the shortest distance to the point (0, 1) of the space ROC. However, we find that the choice of similarity detection tool in source code will depend on conservative or liberal profile of teaching. / O plágio entre alunos de disciplinas introdutórias de programação vem aumentando ao longo do tempo. A facilidade na troca de informações trazida pela Internet pode ser um dos fatores responsáveis por esse aumento. Em muitos casos, os alunos tentam disfarçar o plágio fazendo algumas modificações no código-fonte. Porém, algumas técnicas de disfarce são extremamente complexas e podem não ser detectadas a olho nu. Neste trabalho, foram analisadas as técnicas de detecção e, com base nelas, foi desenvolvido um sistema capaz de detectar plágio em código-fonte. Este sistema é baseado na representação do código como uma árvore sintática abstrata e no algoritmo Karp-Rabin Greedy String Tiling. O sistema foi avaliado utilizando uma base de códigos-fonte de alunos de disciplinas programação. Foi realizada uma comparação baseada em oráculo para comparar o sistema com os demais. O oráculo foi criado a partir da análise do docente da disciplina, onde foi marcado se havia plágio ou não em cada par de código-fonte. Para representar os resultados, foram utilizadas curvas ROC e matrizes de confusão. O mesmo procedimento foi aplicado aos sistemas já existentes, o que permitiu a comparação direta entre os resultados. Mais especificamente, utilizamos o valor da área sob a curva e a distância mínima para o ponto (0, 1) do espaço ROC, uma vez que esses valores representam o desempenho de classificação. A análise dos resultados indica que, para a amostra utilizada, o sistema desenvolvido obteve o maior valor da área sob a curva e também a menor distância para o ponto (0, 1) do espaço ROC. No entanto, concluímos que a escolha de uma ferramenta de detecção de similaridade em código-fonte dependerá bastante do perfil conservador ou liberal do docente.