Semantic Data Integration on the Web of Things

This paper presents a method for the integration of data originating from sensors and actuators that follow different formalisms, although they semantically interlap. We tested our approach one three Web of Things standards published respectively by the Open Mobile Alliance (OMA), the Open Connectivity Foundation (OCF) and the oneM2M foundation. Our method extensively relies on Semantic Web technologies. First, observing that all standards provide a JSON representation of the data they specify, we generate an equivalent RDF representation by exploiting features of the recent JSON-LD format. We then define SPARQL inference rules, part of the new SHACL specification, to align the resulting RDF data with a unified ontology we call the Web of Things cloud. This ontology includes concepts from the SOSA, SSN, SAREF and SEAS ontologies. We evaluated our method by measuring the semantic similarity that exists between the standards OMA, OCF and oneM2M define. Our experiments show that the overlap between these standards