Algoritmos baseados em estimadores de distribuição e técnicas da otimização com muitos objetivos aplicados na refatoração automática de software

• Autor(a) principal: Botelho, Glauber Andrade
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/10762
• topic: Refatoração; Otimização; Engenharia de software; Refactoring; Optimization; Software engineering; CIENCIAS EXATAS E DA TERRA::CIENCIA DA COMPUTACAO

Search Based Software Engineering (SBSE) is a research area in which optimization algorithms are applied to solve Software Engineering problems. SBSE area comprises several sub-areas, among them, Search Based Software Refactoring (SBSR), which deals with automatic software refactoring processes. One of the problems investigated in SBSR is the determination of a sequence of refactorings that provides code improvement, according to predetermined criteria. To model this problem as an optimization problem, it is necessary to define objective functions. In this case, the objective functions are quality metrics used in Software Engineering. Since there are many metrics to consider, the problem of determining sequences of refactorings is a Many-Objective Combinatorial Optimization Problem. Many-Objective optimization comprises a set of algorithms and techniques used to solve problems that take into account more than three objectives. In order to solve problems of this nature, new methods are proposed to reduce the deterioration of the search as the number of objectives increases, among them, the multi-objective evolutionary algorithms, which include the Estimation of Distribution Algorithms (EDA). However, despite having good results in combinatorial optimization problems the investigation of EDA in the context of optimization with many objectives are still incipient. The goal of this work is to investigate the use of EDA in the automatic selection of a sequence of refactorings. In order to achieve this goal, a new EDA is proposed, which incorporates many-objective optimization techniques existing in literature. The proposed algorithm was validated and added to a previously implemented automatic software refactoring framework. Furthermore, a set of experiments was conducted to evaluate the proposed algorithm. The results obtained by the proposed algorithm were compared to the results obtained by algorithms existing in the literature.