The authors describe an expert system, the Specification-Transformation Expert System (STES), which is to translate requirements specifications into design specifications automatically during the development phase of the software life cycle. STES accepts as input a software-requirements specification expressed in terms of dataflow diagrams. Using rules that embody a structured design methodology, STES translates this specification into a template describing a structure chart. STES consist of a knowledge base and an inference engine. The knowledge base contains information on the structured-design methodology and heuristic guidelines to help determine when certain methods should be applied. Given a target software system's requirements specification, the STES inference engine can perform intelligent decision-making and determine a suitable architectural design specification for the software system being designed. STES was originally implemented in OPS5 on a VAX11/780 computer. It has since been ported to an Apollo DN 3000 workstation and integrated with a commercial CASE tool
