物联网服务建模：一种基于环境建模的方法

物联网服务是传统Web服务通过传感器网络向物理环境的延伸,它通过传感器网络感知物理环境中的实体,也向物理环境实体施加作用.与传统Web服务相比,由于物联网服务受到所依赖的物理环境的时间受限性、资源受限性和设备潜在故障概率的影响,物联网服务的响应速度、服务能耗和容错能力等特性成为影响物联网系统整体特性的重要因素.因此,对物联网服务进行全面建模,对物联网服务所处的外部环境进行形式化描述,并结合物理环境模型对物联网服务的性质进行分析,对于确保物联网系统的正确性、稳定性非常必要.本文针对物联网服务的特点,结合基于环境建模的需求工程思想,提出一种基于环境的物联网服务三元问题域建模框架,给出了物联网服务建模本体以及相应的建模原则.在此基础上,提出了一种物联网服务行为建模方法,该方法将物联网服务和物理环境建模为概率时间自动机,将用户期望的服务特性描述为时序逻辑公式,为物联网服务功能行为正确性验证和非功能性约束可满足性验证奠定了基础.

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 infuence of the physical environment（such as the time limitation,the resource limitation and the equipment fault probability）, features of IoT services are more easily afected 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 user＇s desired IoT services features can be described in the temporal logic formula. With our method, the validity of the whole system and the satisfability of its non-functional constraints can be analyzed detailedly and formally.