Event and rule services for achieving a Web-based knowledge network

This paper presents the concept of a Web-based knowledge network. A knowledge model is first described and then the overall architectural framework of the knowledge network is discussed. The implemented prototype system allows providers of information resources and/or application system services to publish not only their data resources and/or services on Web pages, but also their knowledge expressed in forms of events, rules, and triggers associated with the contents and operations of these pages. Internet users can access these Web pages, subscribe to some published events in a registration process, and provide values for event filters and customizable rules. The subscribers can also specify additional triggers and rules of their own that are to be processed on the subscribers' sites. At run-time, when an event is posted by a provider (human or automated application system), event filters are processed, the relevant subscribers are notified, and both the provider and subscribers' triggers and rules are processed on their respective sites. The architectural framework allows both providers and subscribers of information resources and services to contribute their knowledge to the Internet, thus forming a Web-based knowledge network instead of the present data/information network. The knowledge network is constructed by a number of replicable software components, which can be installed at various network sites. They, together with the existing Web servers, form the knowledge Web servers.