Nous proposons une approche basée sur la formulation interactive des requêtes. Notre approche sert à faciliter des tâches d’analyse et de compréhension du code source. Dans cette approche, l’analyste utilise un ensemble de filtres de base (linguistique, structurel, quantitatif, et filtre d’interactivité) pour définir des requêtes complexes. Ces requêtes sont construites à l’aide d’un processus interactif et itératif, où des filtres de base sont choisis et exécutés, et leurs résultats sont visualisés, changés et combinés en utilisant des opérateurs prédéfinis. Nous avons évalués notre approche par l’implantation des récentes contributions en détection de défauts de conception ainsi que la localisation de fonctionnalités dans le code. Nos résultats montrent que, en plus d’être générique, notre approche aide à la mise en œuvre des solutions existantes implémentées par des outils automatiques. / We propose an interactive querying approach for program analysis and comprehension tasks. In our approach, an analyst uses a set of basic filters (linguistic, structural, quantitative, and user selection) to define complex queries. These queries are built following an interactive and iterative process where basic filters are selected and executed, and their results displayed, changed, and combined using predefined operators. We evaluated our querying approach by implementing recent state-of-the-art contributions on feature location and design defect detection. Our results show that, in addition to be generic; our approach helps improving existing solutions implemented by fully-automated tools.

Nesta tese de doutorado, apresentamos uma abordagem para a observação das métricas de código-fonte, estudando-as através de suas distribuições e associações, além de discutir as relações de causalidade e implicações práticas-gerenciais para monitoramento das mesmas. Em nossos estudos avaliamos a distribuição e correlações dos valores das métricas de 38 projetos de software livre, dentre os com mais contribuidores ativos em seus repositórios. Para tal, coletamos e analisamos os valores para cada métrica em mais de 344.872 classes e módulos dos projetos avaliados. Complementarmente, para mostrarmos a utilidade do monitoramento de métricas, descrevemos uma extensão e adaptação do modelo de causalidade do conceito de atratividade de projetos de software livre, que indica uma relação estatística entre os valores das métricas de código-fonte e a quantidade de downloads, contribuidores e atualizações (commits) nos repositórios dos projetos. Para isso, realizamos estudos empíricos com milhares de projetos de software livre. Do ponto de vista prático, também contribuímos com um conjunto de ferramentas inovador para a automação da avaliação de projetos de software livre, com ênfase nos estudos e na seleção de métricas, o que permite a análise de código-fonte de acordo com a percepção de qualidade das comunidades de software livre. Entre as principais contribuições desta tese está uma análise detalhada, em relação ao comportamento, valores e estudos de caso, de 15 métricas de código-fonte, o que representa um avanço em comparação a literatura relacionada ao ampliar o número de métricas avaliadas e propor uma abordagem que visa diminuir as contradições das análises das métricas. / In this Ph.D dissertation we present an approach about source code metrics tracking. We have researched source code metrics distributions and associations to discuss their causality and management-practices implications. Our studies have assessed distributions and correlations of source code metric values on 38 free software projects, which have a lot of activated contributors in their repositories. We have collected and analyzed metrics from 344,872 classes and modules of about 38 free software projects. Additionally, to show how it is useful to track source code metrics, we have extended the model of free software attractiveness to include source code metrics. Our technical attractiveness model indicates a statistical relationship between source code metrics and number of downloads, contributors, and commits in the analyzed free software repositories. For that, we have conducted empirical studies with 8,450 free software projects. From a practical point of view, we have contributed with a set of innovative tools for automated evaluation of free software projects. Our tool allow the analyses of source code metrics that mirror quality perceptions from the free software communities point of view.

Hardware evolves faster than software. While a hardware system might need replacement every one to five years, the average lifespan of a software system is a decade, with some instances living up to several decades. Inevitably, code outlives the platform it was developed for and may become legacy: development of the software stops, but maintenance has to continue to keep up with the evolving ecosystem. No new features are added, but the software is still used to fulfil its original purpose. Even in the cases where it is still functional (which discourages its replacement), legacy code is inefficient, costly to maintain, and a risk to security. This thesis proposes methods to leverage the expertise put in the development of legacy code and to extend its useful lifespan, rather than to throw it away. A novel methodology is proposed, for automatically exploiting platform specific optimisations when retargeting a program to another platform. The key idea is to leverage the optimisation information embedded in vector processing intrinsic functions. The performance of the resulting code is shown to be close to the performance of manually retargeted programs, however with the human labour removed. Building on top of that, the question of discovering optimisation information when there are no hints in the form of intrinsics or annotations is investigated. This thesis postulates that such information can potentially be extracted from profiling the data flow during executions of the program. A context-aware data dependence profiling system is described, detailing previously overlooked aspects in related research. The system is shown to be essential in surpassing the information that can be inferred statically, in particular about loop iterators. Loop iterators are the controlling part of a loop. This thesis describes and evaluates a system for extracting the loop iterators in a program. It is found to significantly outperform previously known techniques and further increases the amount of information about the structure of a program that is available to a compiler. Combining this system with data dependence profiling improves its results even more. Loop iterator recognition enables other code modernising techniques, like source code rejuvenation and commutativity analysis. The former increases the use of idiomatic code and as a result increases the maintainability of the program. The latter can potentially drive parallelisation and thus dramatically improve runtime performance.

The topic of the diploma thesis is the copyright protection of webpages that connects law and webpages and its maintenance and administration performed by website operator. The webpage can be perceived and interpreted in two ways, i.e. as a set of individual elements or as single all-embracing and complex unit that is formed by those elements. The main goal is to analyze the legislation in both ways and to present impacts of it. The initial chapter provides essential basics of copyright law that applies to the rest of the thesis and explains the terminology that is used in following chapters. Second chapter deals with source code that is crucial information for a functioning of every webpage and that stays unknown to most of the webpage users. Third chapter aims at visual identity of a webpages, that means at appearance and design, every element that webpage user can perceive. This chapter also presents conditions under which the individual elements are eligible to be protected in accordance with Czech Copyright Act. A significant part of this chapter is devoted to fonts whose protection is not regulated under Czech law. Literary works, other texts, messages or notice on webpages are subject to analysis of fourth chapter. Accessibility of those works of all kinds on the internet makes almost...

In this diploma thesis, I conduct a research into approaches to consolidating data base and source code base of the Techno.cz webserver, which is the subject of the consolidation. By consolidation I mean bringing the server into the state where documentation is produced according to given requirements, data base is changed in order to improve data structure and consistency and source code base is reorganised in order to unify source code upon one platform, improve file system organization and remove problematic characteristics of the source code in general. The goals of this thesis are to create and describe general process of consolidation, sequence and contents of its steps; to describe contents of consolidation in given areas: documentation, data base and source code base; to describe actual steps made to achieve the final state of the server. My approach to accomplishing these goals is the study of relevant literature and usage of my practical experience in the field of web development. My contribution to the topic is the creation of the general consolidation process that has a potential to be reused by similar projects. Another contribution may be the description of handling the risks and problems that emerged during the consolidation process. This topic may find itself as a valuable source of knowledge for fellow developers facing similar issues. The thesis is divided into eight chapters. After the introduction chapter 2 follows. Chapter 2 describes parameters of the Techno.cz webserver. Chapter 3 discusses software engineering methodologies in order to create suitable consolidation process. Chapter 4, 5, 6 discuss particular fields of consolidation: documentation, data base and source code. In chapter 7 I am trying to assess suitability of created processes and approaches for usage in future development. In the conclusion I summarize the thesis according to required structure.

The topic of this thesis is to analyze the websites of selected faculties in the Czech Republic. There are mainly defined general, legal and theoretical elements and methods of websites and the possibility of further examination and analysis in the extensive theoretical parts The practical part evaluates data outputs based on the analysis of individual pages as well as consultation with an expert in the field. The work is based on current trends, production sites and their contemporary design. The first chapter discusses the criterion and selected methods. The next chapter describes the usability and actual testing of university websites. In conclusion, there is a summary of literature and it is stated relative positions of the university websites and design modifications that can be done on websites of the University of Economics in Prague.

Nesta tese de doutorado, apresentamos uma abordagem para a observação das métricas de código-fonte, estudando-as através de suas distribuições e associações, além de discutir as relações de causalidade e implicações práticas-gerenciais para monitoramento das mesmas. Em nossos estudos avaliamos a distribuição e correlações dos valores das métricas de 38 projetos de software livre, dentre os com mais contribuidores ativos em seus repositórios. Para tal, coletamos e analisamos os valores para cada métrica em mais de 344.872 classes e módulos dos projetos avaliados. Complementarmente, para mostrarmos a utilidade do monitoramento de métricas, descrevemos uma extensão e adaptação do modelo de causalidade do conceito de atratividade de projetos de software livre, que indica uma relação estatística entre os valores das métricas de código-fonte e a quantidade de downloads, contribuidores e atualizações (commits) nos repositórios dos projetos. Para isso, realizamos estudos empíricos com milhares de projetos de software livre. Do ponto de vista prático, também contribuímos com um conjunto de ferramentas inovador para a automação da avaliação de projetos de software livre, com ênfase nos estudos e na seleção de métricas, o que permite a análise de código-fonte de acordo com a percepção de qualidade das comunidades de software livre. Entre as principais contribuições desta tese está uma análise detalhada, em relação ao comportamento, valores e estudos de caso, de 15 métricas de código-fonte, o que representa um avanço em comparação a literatura relacionada ao ampliar o número de métricas avaliadas e propor uma abordagem que visa diminuir as contradições das análises das métricas. / In this Ph.D dissertation we present an approach about source code metrics tracking. We have researched source code metrics distributions and associations to discuss their causality and management-practices implications. Our studies have assessed distributions and correlations of source code metric values on 38 free software projects, which have a lot of activated contributors in their repositories. We have collected and analyzed metrics from 344,872 classes and modules of about 38 free software projects. Additionally, to show how it is useful to track source code metrics, we have extended the model of free software attractiveness to include source code metrics. Our technical attractiveness model indicates a statistical relationship between source code metrics and number of downloads, contributors, and commits in the analyzed free software repositories. For that, we have conducted empirical studies with 8,450 free software projects. From a practical point of view, we have contributed with a set of innovative tools for automated evaluation of free software projects. Our tool allow the analyses of source code metrics that mirror quality perceptions from the free software communities point of view.

The purpose of this paper is to clarify the differences in latency between PostgreSQL and MongoDB as a consequence of their differences in software architecture. This has been achieved through benchmarking of Insert, Read and Update operations with the tool “Yahoo! Cloud Serving Benchmark”, and through source code analysis of both database management systems (DBMSs). The overall structure of the architecture has been researched with Big O notation as a tool to examine the complexity of the source code. The result from the benchmarking show that the latency for Insert and Update operations were lower for MongoDB, while the latency for Read was lower for PostgreSQL. The results from the source code analysis show that both DBMSs have a complexity of O(n), but that there are multiple differences in their software architecture affecting latency. The most important difference was the length of the parsing process which was larger for PostgreSQL. The conclusion is that there are significant differences in latency and source code and that room exists for further research in the field. The biggest limitation of the experiment consist of factors such as background processes which affected latency and could not be eliminated, resulting in a low validity.

This thesis deals with source-code migration of high-level programming languages using decompilation. A migration tool developed within the thesis is built on top of the middle-end and back-end parts of Lissom project decompiler. Several compilers generating LLVM IR code from input languages are discussed. Compilers suitable for integration to the migration tool were chosen. Compiled LLVM IR code is an input of the decompiler's optimizing middle-end. The output from the migration tool is a code in the C language or Python-like language generated by the back-end of the decompiler. The input languages are Fortran and its dialects, C/C++/Objective-C/Objective-C++, and D. The thesis describes problems connected with migration of these languages, their solutions, and ways to improve quality and readability of the produced source code.

Software maintenance and the understanding of where in the source code features are implemented are two strongly coupled tasks that make up a large portion of the effort spent on developing applications. The concept of feature location investigated in this thesis can serve as a supporting factor in those tasks as it facilitates the automation of otherwise manual searches for source code artifacts. Challenges in this subject area include the aggregation and composition of a training corpus from historical codebase data for models as well as the integration and optimization of qualified topic modeling techniques. Building up on previous research, this thesis provides a comparison of two different techniques and introduces a toolkit that can be used to reproduce and extend on the results discussed. Specifically, in this thesis a changeset-based approach to feature location is pursued and applied to a large open-source Java project. The project is used to optimize and evaluate the performance of Latent Dirichlet Allocation models and Pachinko Allocation models, as well as to compare the accuracy of the two models with each other. As discussed at the end of the thesis, the results do not indicate a clear favorite between the models. Instead, the outcome of the comparison depends on the metric and viewpoint from which it is assessed.