VIBE: looking for Variability In amBiguous rEquirements

Variability is a characteristic of a software project and describes the fact that a system can be configured in different ways, obtaining different products (variants) from a common code base, accordingly to the software product line paradigm. This paradigm can be conveniently applied in all phases of the software process, starting from the definition and analysis of the requirements. We observe that often requirements contain ambiguities which can reveal an unintentional and implicit source of variability, that has to be detected. To this end we define VIBE, a tool supported process to identify variability aspects in requirements documents. VIBE is defined on the basis of a study of the different sources of ambiguity in natural language requirements documents that are useful to recognize potential variability, and is characterized by the use of a NLP tool customized to detect variability indicators. The tool to be used in VIBE is selected from a number of ambiguity detection tools, after a comparison of their customization features. The validation of VIBE is conducted using real-world requirements documents.