Hypermedia Research Unit Seminar
Event Date July 2, 2009
Location – J304
A Hypermedia Research Unit Seminar will take place on Thursday 2nd July, 15.00 in J304
Will Mepham from CEPE will present his PhD research on the application of Semantic Web techniques to model the flow of online computer games.
Towards discrete event calculus for the semantic web!
The event calculus is a logical formalism that provides the ability for a software agent to understand sequences of events and how they can affect system states. The event calculus formalism has grown out of AI investigations on small scale knowledge bases; we are interested in the application of this formalism to the web at large through semantic web languages which offer access to a continually growing body of interconnected knowledge bases.
The talk will start with introductions to the semantic web languages stack and the event calculus, together with our motivation for trying to combine them.
It will describe a simplified version of the event calculus that deals with discrete timepoints. The axioms are implemented in OWL/SWRL with a rules engine (Jess) to extract inferences from the model. This will be explained briefly.
We define a knowledgebase that is divided into three distinct sections: a current timepoint, a narrative and a set of observations. The knowledgebase is built from an ontology that includes the building blocks of event calculus and a specific application domain. Using a rules engine like Jess we can infer new statements about system states (=fluents) from an existing set of events fluents and domain rules.
Some things are impossible to express through SWRL and Jess, for instance existential quantification or negation. This makes some of the axioms in the event calculus difficult to express, so we have to provide these with a general purpose programming language. To implement the necessary workarounds we have implemented a software prototype that can interpret and build discrete event calculus statements.
The talk will present the software prototype, which is inevitably at a very rough stage but can serve as proof of concept. There will be a demo afterwards as well.
The talk will round off with some possible application areas for this approach, particularly w.r.t. games and service software built around online games.
tagged: HRU
