Knowledge Base Management Systems (KBMS) based on Description Logics perform deductions with intensional descriptions, thus providing novel services, and now finding commercial applications. This research considers facilitating the specification and implementation of a family of such KBMS, through the extension of a core system, ProtoDL, by the addition of new description constructors. Specifically, the objectives include (i) a formal notation for specifying the semantics of Description Logics; (ii) a system, with a score of procedures that need to be completed for every new constructor being added to the KBMS; (iii) heuristics linking the implementation and specification. Thereafter, given a particular application (in the domain of Software Information Systems --- the chosen area for experiments), the prospective KB developer determines suitable extensions to the description language and its inferences, with the help of a "knowledge language engineer"; the latter then augments the ProtoDL implementation by filling in and modifying the appropriate procedures/modules. The advantages of such extensible KBMS include: (1) meeting the need of many practical applications for domain-dependent constructors (e.g., dealing with time, plans, etc.); (2) a novel approach to the expressiveness vs. computational intractability stand-off: starting with a limited language and extending it in an application-dependent way.
