Standardized and efficient RDF encoding for constrained embedded networks

Abstract

In the context of Web of Things (WoT), embedded networks have to face the challenge of getting ever more complex. The complexity arises as the number of interchanging heterogeneous devices and different hardware resource classes always increase. When it comes to the development and the use of embedded networks in the WoT domain, Semantic Web technologies are seen as one way to tackle this complexity. For example, properties and capabilities of embedded devices may be semantically described in order to enable an effective search over different classes of devices, semantic data integration may be deployed to integrate data produced by these devices, or embedded devices may be empowered to reason about semantic data in the context of WoT applications. Despite these possibilities, a wide adoption of Semantic Web or Linked Data technologies in the domain of embedded networks has not been established yet. One reason for this is an inefficient representation of semantic data. Serialisation formats of RDF data, such as for instance a plain-text XML, are not suitable for embedded devices. In this paper, we present an approach that enables constrained devices, such as microcontrollers with very limited hardware resources, to store and process semantic data. Our approach is based on theW3C Efficient XML Interchange (EXI) format. To show the applicability of the approach, we provide an EXI-based μRDF Store and show associated evaluation results.