Analogical and Dependency Directed Reasoning Strategies for Large Systems Evolution

The mainterlance of large infor~ilat,ion systerlls involves cor~t i~i i~or ts clesigti ruoclifications to designs in response to evolving business corlclitio~is or cllarlging user req~~irerrler~ts. Because of the con~plexity barrier associated with engineering suclt systems, charlges car1 be L E ~ hoc and prone to errors. Based or1 our observations of such a process in the oil iilctustry, we believe that the systems ~~lairl ter~atlce activity would benefit greatly if the process knowledge reflecting the teleology of a ctesigrl could he captured a11d used in order to reasorl about changing requirenlerits. n11d to ciesig~l parts of systenls t,hat might be nsi~rlilar" to existing ones. In t,his paper, we ileacribe a partially inlpleiilerlted formalism called REMAP (REpresel l ta t io~~ ancf I21Airlterl;~rlce of Process knowledge) that accuniulates design process knowledge t,o manage systelrls evolutiorl. T o acconiplish this, REMAP acquires and mairltains dependerlcies arrlorlg the design decisions rriade during a prototyping process as well as the general domain-specific design rules on whicii such dependencies are based. Ttlis knowledge can then be applied to prototype refinement, systenls maintenance, arid the re-use of existing designs to construct "similarn design fragments. Center for Digital Economy Research Stem School of Business IVorking Paper IS-85-66