CDQL: a generic context representation and querying approach for internet of things applications

© 2016 ACM. As the standardization efforts for IoT is fast progressing, we will quickly get to a point where context derived from IoT data and relations will be the underpinning factor to enable interaction between "smart things". Therefore, having a generic approach for describing and querying context is crucial for the future of IoT applications. In this paper, we propose Context Definition and Query Language (CDQL), an advanced approach that enables things to exchange context. CDQL consists of two main parts: Context Definition Model, which is designed to describe the contextual attributes and context related capabilities of each "thing"; and Context Query Language (CQL), which is a flexible query language to express contextual information requirements without considering details of the underlying data structure. We exemplify the usage of the proposed CDQL, via a smart city use case study that highlight how CDQL can be utilized to deliver context information to IoT applications.