Environment based modeling approach for services in the Internet of Things

Services in Internet of Things (IoT services) are extensions of traditional Web services. Through sensor networks, IoT services can communicate directly with the entities in the physical environment, and even impact them directly. So, because of the influence of the physical environment (such as the time limitation, the resource limitation and the equipment fault probability), features of IoT services are more easily affected by the physical environment than the traditional Web service. In this case, the response time, the service consumption and the fault-tolerant ability become important factors in the performance of the whole IoT system. Therefore, modeling the IoT services detailedly and formally is very important for the analysis and prediction of the performance of the whole IoT system. In this paper, we propose an environment based IoT service modeling framework as well as an ontology of the IoT service and a triple-element model, and advance the corresponding modeling principle. Based on this framework, we proposed a detailed IoT model method, in which the IoT services and their corresponding environment can be described in probabilistic timed automata. The users desired IoT services features can be described in the temporal logic formula. With our method, the validity of the whole system and the satisfiability of its non-functional constraints can be analyzed detailedly and formally.