Meta-level service type specifications

The concept of a service type plays a fundamental role in specifying and trading client requests and service offers. Existing middleware architectures use syntactic interface type specifications based on specific IDLs, while ODP standards do not prescribe any particular IDL. Neither approach can handle semantical information beyond interface structure and quantitative service attributes. We present a meta-level type specification technique that is generic and flexible to express any kind of information related to a type, not only its operational interface structure. The technique uses a knowledge representation notation called conceptual graphs. We have integrated this method into a trading system which is capable of translating different IDL specifications into conceptual graphs and deciding their potential subtype relationship. The trader can be configured flexibly to handle and match any kind of information that can be represented as a conceptual graph.