IoT Service Combination Modeling Methods And Tools

In order to meet the needs of loose coupling and flexible expansion in the continuous construction and development of the Internet of Things,the service-oriented architecture is gradually becoming a mainstream architecture method of the Internet of Things system.Under the service-oriented IoT system architecture,the functions of the IoT system’s object,edge,and cloud can be abstracted and organized into IoT services,and these IoT services can be combined according to requirements to achieve more complex IoT application functions.However,as a social-information system that integrates the physical world and the information world,the Internet of Things system has new characteristics such as complex environment,uncertain demand,and numerous services,which brings many new problems and challenges to IoT service combinations,such as IoT service Composition involves a variety of constituent elements,IoT service composition requires strong semantic description capability,high flexibility and dynamic adaptability of the composition model,and lack of effective visual modeling tools that support IoT service composition modeling.The traditional centralized service composition model based on predefined and tightly coupled service interaction processes is difficult to meet the needs of service composition in highly complex,dynamic and distributed IoT application scenarios.Therefore,in response to the above problems,this paper studies the modeling methods and tools of IoT service composition,and mainly carries out the following four aspects of work:1.In view of the physical-information fusion characteristics of the Internet of Things system,the core elements of the IoT service system are analyzed by using the activity theory,and the core contents such as the IoT service model,the IoT service system environment model,and the physical entity model are established to provide an IoT service combination Modeling lays the groundwork.2.Aiming at the environmental awareness-response requirements of the Internet of Things system,an IoT service composition model based on spatio-temporal enhanced event response rules(ST-ECA)is proposed.The event combination rules between events support the collection and fusion modeling of IoT services from different spatio-temporal sources in the physical world according to different events,and on the basis of BPMN2.0,IoT service combination construction is defined through IoT service and ST-ECA rules model language.At the same time,the effectiveness of the model is verified through a case study in the highway application scenario3.Aiming at the dynamic service matching problem in the IoT service composition model,an event-aware dynamic matching mechanism for IoT service composition is proposed to support automatic perception of changes in IoT service data and generate corresponding events so that rules can process events.This paper proposes an algorithm for monitoring the mismatch of rules in different tasks in IoT service composition,and detects whether the rules match between different tasks of business process composition through the algorithm,and can be combined smoothly.Experiments on relevant datasets show that the mechanism and corresponding algorithms can meet the delay-sensitive and real-time requirements of IoT applications.4.On the basis of the above work,a visual IoT service composition modeling tool is designed and implemented by using the BPMN.The rule definition tool defines the IoT service event processing rules in the task,and realizes the execution support of the IoT service composition model based on the Drools rule engine and the Flowable process engine.In addition,the tool can also manage the deployment,control,and debugging of the modeled IoT service composition model.