Model based requirements specification and validation for component architectures

Requirements specification is a major component of the system development cycle. Mistakes and omissions in requirements documents lead to ambiguous or wrong interpretation by engineers and, in turn, cause errors that trickle down in design and implementation with consequences on the overall development cost. In this paper we describe a methodology for requirements specification that aims to alleviate the above issues and that produces models for functional requirements that can be automatically validated for completeness and consistency. This methodology is part of the Requirements Driven Design Automation framework (RDDA) that we develop for component-based system development. The RDDA framework uses an ontology-based language for semantic description of functional product requirements, UM-L/SysML structure diagrams, component constraints, and Quality of Service. The front end method for requirements specification is the SysML editor in Rhapsody. A requirements model in OWL is converted from SysML XMI representation. The specification is validated for completeness and consistency with a ruled-based system implemented in Prolog. With our methodology, omissions and several types of consistency errors present in the requirements specification are detected early on, before the design stage.