The symbIoTe Solution for Semantic and Syntactic Interoperability of Cloud-based IoT Platforms
The current IoT landscape is dominated by cloud-based platforms offering non-standardized interfaces to access virtualized IoT resources and adopting proprietary information models. The implementation of cross-platform and cross-domain IoT applications becomes cumbersome and usually leads to custom solutions, tailored to the involved platforms, due to the semantic and syntactic incompatibilities. The symbIoTe approach offers mediation services for search and controlled access to IoT resources (sensors, actuators, and related services) across platforms in a uniform way. It provides an IoT Portal with registration and search capabilities using semantic web technologies for semantic interoperability, and an abstraction layer for unified and secure access to those resources across distributed IoT platform instances for syntactic interoperability. In this paper, we present the general concepts and design decisions built into the symbIoTe open source middleware and showcase the evolving symbIoTe ecosystem which facilitates the rapid development of innovative cross-platform IoT applications. The open IoT Portal currently integrates 15 IoT platforms and data sources for Smart City and Smart Residence domains, and hosts metadata registering more than 4,000 various IoT resources.