An open system knowledge framework and its bridge evaluation application

We present OPUS, a framework that provides design guidelines for the systematic building of independent, and potentially heterogeneous, knowledge base programs for the domains of large physical structures. The term open-system refers to the integration of several of these programs to solve problems beyond their individual capabilities. The OPUS framework organizes data and knowledge about the domain into three layers. The kernel layer encodes primary domain knowledge into hierarchies of objects, the scenario layer contains autonomous knowledge programs for specific applications, and the utility layer supports system interface and inference methods. OPUS provides a focus for knowledge organization and rapid prototyping, supports multiple schemes of inference and representation, copes with the maintenance and reuse of knowledge, and enables different levels of abstraction and views of knowledge. An OPUS system BFC has been developed to cover wide-ranging applications in bridge evaluation. Examples are taken from this application to illustrate data constructs and reasoning schemes based on the OPUS framework