A Device-Centric Policy Conflict in IoT

Policy-based management provides Web of Things (WoT) system with the ability to describe its requirements and functionality, so that desired service goals are achieved. This requires WoT system provisioning smart things which can work under the guidance of policies. However, policy makers with less awareness of specific safety constraints of smart things may create harmful policies, which make smart things work in unexpected situations and cause safety issues. From the view of smart things, the notion of safety issues is two-fold: First, devices themselves work in an unsound and unsecure state, second, devices are influenced by other devices with same or contradict function. We identify these safety issues as device-centric modality conflicts and interest conflicts, and then define a specific conflict detection approach for these conflicts. In this paper, we demonstrate the use of the conflict detection approach to detect device-centric conflicts in two cases. Finally, we conduct three experiments to evaluate the accuracy and time performance of the detection approach.