Conflict Detection Scheme Based on Formal Rule Model for Smart Building Systems

Smart building systems can provide flexible and configurational sensing and controlling operations according to users' requirements. As the number and the complexity of service rules customized by users have significantly increased, there is an increasing danger of conflict during the interaction process between users and the system. To address this issue, we propose a new rule conflict detection scheme tailored for the smart building system. First, we present a formal rule model UTEA based on User, Triggers, Environment entities, and Actuators. This model can handle not only controlled devices with discrete status but also real-valued environmental data such as temperature and humidity. In addition, this model takes multiple users with different authorities into account. Second, we define 11 rule relations and further classify conflicts into five categories. Third, we implement a rule storage system for detecting conflicts and design a conflict detection algorithm, which can detect the conflict between two rules as well as cycle conflict/multicross contradiction among multiple rules. We evaluated our scheme in a real smart building system with more than 30 000 service rules. The experiment results show that our scheme improves the performance in terms of error/missed-detection rates and running time.