The DigiHome Service-Oriented Platform

Nowadays, the computational devices are everywhere. In malls, offices, streets, cars and even in homes we can find devices providing and consuming functionality in order to improve the user satisfaction. These devices include sensors that provide information about the environment state (e.g., temperature, occupancy, light levels), service providers (e.g., Internet TVs, GPS), smartphones (that contain user preferences), and actuators that act on the environment (e.g., closing the blinds, activating the alarm, changing the temperature). Although these devices exhibit communication capabilities, their integration into a larger monitoring system remains a challenging task, partly due to the strong heterogeneity of technologies and protocols. Therefore, in this article we focus on home environments and propose a middleware solution, called DigiHome, which applies the SCA (Service Component Architecture) component model in order to integrate data and events generated by heterogeneous devices in this kind of environments. DigiHome exploits the SCA extensibility to incorporate the REST (REpresentational State Transfer) architectural style, and in this way leverages on the integration of multi-scale systems-of-systems (from Wireless Sensor Networks to the Internet). Additionally, the platform applies CEP (Complex Event Processing) technology that detects application-specific situations. We claim that the modularization of concerns fostered by DigiHome and materialized in a service-oriented architecture, makes it easier to incorporate new services and devices in smart home environments. The benefits of the DigiHome platform are demonstrated on smart home scenarios covering home automation, emergency detection, and energy saving situations.