Device interoperability and service discovery in smart environments

Smart Environments (SE), and in particular Smart Homes, have attracted the attention of many researchers and industrial vendors. In such environments, according to the Ambient Intelligence paradigm, devices operate collectively using any information describing the environment (also known as the context-information) in order to support users in accomplishing their tasks. SE devices are characterized by several properties: they are designed to react autonomously to specific events, they are aware of the context, they manage sensitive information concerning the users, they adopt a service-oriented model in order to interact with other devices, and they interact by means of various applications and communication protocols. Cooperation with devices in SE is thus complex. This thesis deals with two problems that still represent a barrier to the development of many SE applications. The thesis examines how to interact with low-power devices, which is refereed to as device interoperability, and how to discover the functionalities that mobile devices offer, namely the service discovery problem. The rest part of the thesis describes the design of ZB4O an integration gateway for low-power devices based on the ZigBee specification. The growing market for ZigBee-ready appliances makes the ZigBee specification an important technology-enabler for SE. However, accessing such devices entails an easy interaction model with IP-based networks that are already present in most SE. Therefore, this work presents an open source platform that seamlessly integrates ZigBee devices with applications running on SE. The thesis describes the evaluation process of ZB4O with various trials organized over the last year of two EU projects, as well as the integration of ZB4O with UPnP and a RESTful approach. SE devices can also export their functionalities with a service-oriented approach. In fact, every resource offered by a device can be seen as a service available for other devices. The second problem studied in this thesis is the service discovery and it deals with how to advertise and query services in SE. The scenario considered for the service discovery problem is characterized by mobile devices carried by people roaming in SE. Hence, mobility and sociality are two key-factors that make the service discovery problem more complex and challenging. The thesis presents two algorithms, termed SIDEMAN and CORDIAL, for the service discovery in Mobile Social Networks (MSN) which are evaluated with real and synthetic simulation scenarios.