GRAIL/KAOS: an environment for goal-driven requirements analysis, integration and layout

The KAOS methodology provides a language, a method, and meta-level knowledge for goal-driven requirements elaboration. The language provides a rich ontology for capturing requirements in terms of goals, constraints, objects, actions, agents etc. Links between requirements are represented its well to capture refinements, conflicts, operationalizations, responsibility assignments, etc. The KAOS specification language is a multi-paradigm language with a two-level structure: an outer semantic net layer for declaring concepts, their attributes and links to other concepts, and an inner formal assertion layer for formally defining the concept. The latter combines a real-time temporal logic for the specification of goals, constraints, and objects, and standard pre-/postconditions for the specification of actions and their strengthening to ensure the constraints