Content-based sensor search for the Web of Things

In the emerging Web of Things (WoT), the real-time state of real-world objects is published by Internet-connected sensors using Web technologies. A key service in the WoT will be a search engine that allows searching for real-world objects with a certain state. We propose content-based sensor search, where given a search query that is composed of a range of sensor values, sensors that have been reading values in that range at the time of the query are found. In this paper, we present an approach based on fuzzy sets to realize scalable content-based sensor search in the WoT. Using sensor data sets obtained from real deployments, we find that our approach results in a low communication overhead. To demonstrate the practical feasibility of our approach, we implemented a prototypical search engine that enables the user to search for sensors that are available on the Web.