Abstract: The present invention relates to a method for answering a query (60) directed to a knowledge base. The basic idea under-lying the present invention is to define a generic knowledge base with generic representatives (30) and generic rules (140). Generic representatives (30) represent the structure of objects (20) of the knowledge base. This enables generic rules (140), which represent the structure of the rules (50) of the knowledge base, to be applied to the generic representatives (30) without evaluating the corresponding objects (20) in a first step. In a second step, the inferred generic answers (90) (which are generic representatives (30)) can be used to restrict the original query (60) to objects (20) which have an appropriate structure. In a similar way, the generic representatives (30) applied for inference can be used to restrict the rules (50) of the knowledge base to objects (20) which have an appropriate structure.

Abstract: An inference engine is described with improved speed in evaluating queries posed to a data structure based on an ontology with a declarative set of rules. The inference engine comprises: rule rewriters, a rule compiler, and an operator net. The operator net comprises a graph with operators as nodes and with connections between the operators as edges of the graph. The operators serve for: retrieving facts; matching facts and variables in rules; expressing rule bodies and rule heads; expressing negations; and expressing logical AND operations between rule bodies. The operator net is a very general and versatile representation of the rules and queries. It also lends itself easily to multithreading and debugging.

Abstract: A system for enterprise information integration is described. The system is based on different layers: the data sources, source ontologies corresponding to the data schema of the data sources, an integration ontology integrating the different source ontologies, a level of query input, preferably in the form of a web service. Between the levels, mapping rules are used. These mapping rules and the entire system are based on predicate logic. The queries are answered with the help of the rules using inference based on predicate logic.

Abstract: A method of storing and retrieving data in a computer system comprises steps of forming at least one object model, the object model including at least one class structure; allocating data according to one or more classes of said at least one class structure; providing a set of rules, the rules forming a declarative system and linking components of class structures; providing a query command; and in response to the query command, processing a series of said rules to obtain one or more output variables.