Review of Standard Ontologies for the Web of Things

To open isolated Internet of Things (IoT) silos, the Web of Things (WoT) integrates IoT into the Web promoting an architecture with easy access APIs and applications, and ontologies further improve the data interoperability and federation capability of IoT platforms. With the increasing industry adoption of semantic technologies, a number of ontologies has been defined and standardized, covering different layers of WoT. Although the best practice in data management is to use standardized ontologies as much as possible, users without prior knowledge can hardly select the standard that meets the specific needs and context. This paper provides a general review of standardized WoT ontologies and identifies their coverage of different WoT layers. Firstly, we introduce some background on WoT and ontologies; we then present two WoT architectures, an IoT-oriented one and a Web-oriented one, as evaluation criteria for ontology coverage; in the following, we introduce and analyze the representative standardized WoT ontologies based on criteria. Lastly, we summarize our work and shed light on further directions of WoT ontology development.