Integration in the Internet of Things: A semantic middleware approach to integration

The advent of the Internet of Things (IoT) opens a wide spectrum of interesting oppor- tunities for the creation of novel scenarios. By putting in communication devices such as sensors and actuators, in conjunction with mainstream technologies, IoT enables a whole set of new services in almost any domain to be provided, from building automation to Smart City, E-Health and assistive technologies, only to name a few. Nevertheless, the integration of dierent protocols and technologies remain to date one of the main challenges in IoT. The proposed solutions have evolved following the heterogeneity increment of the technologies employed for complex scenarios, passing from ad-hoc solutions on a per-connection basis (N-to-N ), to solutions that use frameworks as middleware (N-to- 1 ). N-to-1 solutions that have shown interesting features use frameworks modeled on the Publish/Subscribe (P/S) design pattern. This type of frameworks provides facilities to manage the exchange of communications in presence of large number of heterogeneous communication technologies. However, how to eciently interface those technologies to a common framework still remains an open issue. In this work we propose to surround a P/S framework with a layer that allows us to easily interface the various communication technologies with the framework. We describe how to model this layer, and we show how to implement simple adaptors that can be used to interface a technology to the selected P/S framework. We show how our approach makes the integration of heterogeneous technologies easier and how it enables scenarios' recongurations even at run time. By using such an approach, designers can focus on the business logic of the scenario rather than on the low level technological details of the integration. We inform the reader about the lessons learned throughout the realization of the proposed approach and about the tasks that we found more challenging in making the nal system; by doing so we believe to inculcate into the reader some questions that could lead to some interesting future research in order to address some challenges that remain still open.