Towards a Binary Object Notation for RDF

The recent JSON-LD standard, that specifies an object notation for RDF, has been adopted by a number of data providers on the Web. In this paper, we present a novel usage of JSON-LD, as a compact format to exchange and query RDF data in constrained environments, in the context of the Web of Things. A typical exchange between Web of Things agents involves small pieces of semantically described data (RDF data sets of less than hundred triples). In this context, we show how JSON-LD, serialized in binary JSON formats like EXI4JSON and CBOR, outperforms the state-of-the-art. Our experiments were performed on data sets provided by the literature, as well as a production data set exported from Siemens Desigo CC. We also provide a formalism for JSON-LD and show how it offers a lightweight alternative to SPARQL via JSON-LD framing (with polynomial complexity), which makes it a good candidate as a query mechanism in constrained environments.