Expressing JSD in Z

We propose the use of Z as the formal notation to express Jackson System Development (JSD) specifications where JSD is to serve as the mechanism to help the analysis of problem domains. A function process in JSD specifications is manifested by an operation schema. A model process is treated as an active entity that requires an operation on its data store to add a new instance to the collection of existing instances. The model process is thus translated into a state schema, and its related operations are converted into the operation schemas with instances set that can be modified by the operations. A structure diagram is transformed into a state transition diagram and then converted into its Z specifications. Cardinality relationships between processes are translated into Z notations based upon the notion of rough merges. These are illustrated using the problem domain of a car rental system.