Search and similarity based selection of use case scenarios: An empirical study

Use case modeling is a well-known requirements specification method and has been widely applied in practice. Use case scenarios of use case models are input elements for requirements inspection and analysis, requirements-based testing, and other downstream activities. It is, however, a practical challenge to inspect all use case scenarios that can be obtained from any non-trivial use case model, as such an inspection activity is often performed manually by domain experts. Therefore, it is needed to propose an automated solution for selecting a subset of use case scenarios with the ultimate aim of enabling cost-effective requirements (use case) inspection, analysis, and other relevant activities. Our solution is built on a natural language based, restricted use case modeling methodology (named as RUCM), in the sense that requirements specifications are specified as RUCM use case models. Use case scenarios can be automatically derived from RUCM use case models with the already established Zen-RUCM framework. In this paper, we propose a search-based and similarity-based approach called S3RCUM, through an empirical study, to select most diverse use case scenarios to enable cost-effective use case inspections. The empirical study was designed to evaluate the performance of three search algorithms together with eight similarity functions, through one real-world case study and six case studies from literature. Results show that (1+1) Evolutionary Algorithm together with Needleman-Wunsch similarity function significantly outperformed the other 31 combinations of the search algorithms and similarity functions. The combination managed to select 50% of all the generated RUCM use case scenarios for all the case studies to detect all the seeded defects.