Preserving properties in system redesign:: Rule-based approach

This paper deals with stepwise development of systems based on rule-based approach. Modeling using this approach usually starts with a rough model of a system which is refined in further steps. This approach is based on rules and transformations as known from theory of HLR systems. Preservation of certain system properties during this process is of importance. In the context of Petri nets the developed property preserving rules and transformations restrict the variety of modeling possibilities to refinement of the system by additional details. The concept for conceptual change and redesign of a part of the modeled system is of interest. Up to now the request for a large change of structure of the modeled system forced the redevelopment of the whole system from origin. Otherwise the property preserving rules could not be employed and the tedious investigation of system properties had to be done for the final system. In this paper we describe the possibility. of building new property preserving rules from other ones which are suitable for redesign of system's parts.