Task-based specifications through conceptual graphs

[[abstract]]We propose the use of conceptual graphs to express task based specifications in which the specification is driven by the task structure of problem solving knowledge, pieces of the specification can be refined iteratively and verification is performed for a single layer or between layers. Issues in mapping task based specifications into conceptual graphs are identified for example, the representation of constraints, the relationship between a task, its constraints and state model, rigid and soft postconditions, the distinction between follow and immediately follow operators, and the composition operator in task state expressions. To alleviate the problems, the notion of demons has been adopted to represent task state expressions as well as state models. Constraint overlays have been used for describing the state model, and canonical formation rules have been applied to compose task state expressions. These are illustrated using the problem domain of R1/SOAR