Rule-based Programming of User Agents for Linked Data

Tobias Käfer, Andreas Harth

Abstract: While current Semantic Web languages and technologies are well-suited for accessing and integrating static data, methods and tech-nologies for the handling of dynamic aspects – required in manymodern web environments – are largely missing. We propose to useAbstract State Machines (ASMs) as the formal basis for dealing withchanges in Linked Data, which is the combination of the ResourceDescription Framework (RDF) with the Hypertext Transfer Proto-col (HTTP). We provide a synthesis of ASMs and Linked Data andshow how the combination aligns with the relevant specificationssuch as the Request/Response communication in HTTP, the guide-lines for updating resource state in the Linked Data Platform (LDP)specification, and the formal grounding of RDF in model theory.Based on the formalisation of Linked Data resources that changestate over time, we present the syntax and operational semantics ofa small rule-based language to specify user agents that use HTTPto interact with Linked Data as the interface to the environment.We show the feasibility of the approach in an evaluation involvingthe specification of automation in a Smart Building scenario, wherethe presented approach serves as a theoretical foundation.