Software Product Line (SPL) provides the facility to systematically reuse of software improving the efficiency of software development regarding time, cost and quality. The main idea of SPL is to identify the common core functionality that can be implemented once and reused afterwards. A variant model has also to be developed to manage the variants of the SPL. Usually, a domain model consisting of the common and variant requirements is developed during domain engineering phase to alleviate the reuse opportunity. The authors present a product line model comprising of a variant part for the management of variant and a decision table to depict the customization of decision regarding each variant. Feature diagrams are widely used to model SPL variants. Both feature diagram and our variant model, which is based on tabular method, lacks logically sound formal representation and hence, not amenable to formal verification. Formal representation and verification of SPL has gained much interest in recent years. This chapter presents a logical representation of the variant model by using first order logic. With this representation, the table based variant model as well as the graphical feature diagram can now be verified logically. Besides applying first-order-logic to model the features, the authors also present an approach to model and analyze SPL model by using semantic web approach using OWL-DL. The OWL-DL representation also facilitates the search and maintenance of feature models and support knowledge sharing within a reusable engineering context. Reasoning tools are used to verify the consistency of the feature configuration for both logic-based and semantic web-based approaches.
