Abstract--Concept or feature identification, i.e., the identification of the source code fragments implementing a particular feature, is a crucial task during software understanding and maintenance. This paper proposes an approach to identify concepts in execution traces by finding cohesive and decoupled fragments of the traces. The approach relies on search-based optimization techniques, textual analysis of the system source code using latent semantic indexing, and trace compression techniques. It is evaluated to identify features from execution traces of two open source systems from different domains, JHotDraw and ArgoUML. Results show that the approach is always able to identify trace segments implementing concepts with a high precision and, for highly cohesive concepts, with a high overlap with the manually-built oracle. Keywords--Concept location, dynamic analysis, information retrieval.