2.1 Physical entity class of the Internet of Things The physical entity class is an abstraction of the basic physical components of the Internet of Things. The physical entity class not only includes the abstractions of the items that need to be connected to the Internet of Things and the devices that connect these items, but also includes existing components in the existing network. The abstraction of physical units (such as servers and routers) necessary for the Internet of Things. As shown in Figure 2, physical entity classes can be instantiated as devices, servers, management stations, and routers. These physical entities instantiated by the Internet of Things are the basic physical entities of the Internet of Things. Devices in the Internet of Things information model refer to a type of physical entity class instance that has object awareness capabilities and is different from network data transmission equipment. It can be further instantiated as Tag device, sensor device and actuator device. The tag device is associated with the tagged item, the sensor device is associated with the object being sensed, and the actuator device is associated with the object being executed.
2.2 Internet of Things Resource Entity Class The resource entity class is the abstraction of functional units that provide the basic capabilities of the Internet of Things. The resource entity class not only includes the abstraction of functional units required by the Internet of Things that are directly related to items, but also includes the existing network It is an abstraction of the resources (such as computing resources, communication resources, management resources) that the Internet of Things must have. The Internet of Things resource entity class includes basic capabilities such as Internet of Things data representation, storage, transmission, fusion, query and update. As shown in Figure 2 As shown, the resource entity class can be instantiated into item data, computing resources, management resources and communication resources. Among them, communication resources refer to the communication functional unit for network data transmission in the Internet of Things. It is related to the existing ones in the existing network. , there is an association relationship between the physical entity class instances necessary to form the Internet of Things, such as routers, switches, etc.
2.3 Internet of Things Service Entity Class The service entity class is an abstraction of functional units that provide basic services of the Internet of Things. The service entity class not only includes the abstraction of functional units required for services related to items provided by the Internet of Things, but also includes existing network Some service units (such as application services, management services, communication services, etc.) that the Internet of Things must provide are abstract. Multiple service entity class abstract operations can create combined service functional units through service combination. The Internet of Things service entity classes include IoT application support capabilities.
As shown in Figure 2, the service entity class can be instantiated into item service, application service, management service and communication service. Application service can be further instantiated into intelligent application service, management service can be further instantiated into intelligent management service, and communication service can be further instantiated into It is further instantiated as a machine to machine communication (M2M) service.
As an instantiation of application services, intelligent application services extend the autonomous service characteristics and related methods of application services, making application service entities have intelligent service capabilities.
M2M services only provide data communication services between machines and do not involve operations such as representation, query, update, fusion, and mining of item services. M2M services and item services are independent service classes. Both can be used according to the application. requirements, combined into a relatively complete independent Internet of Things service.
2.5 Analysis of related IoT information model The IoT information model constructed here not only includes all information entity classes of the IoT information model constructed in the literature [6], but also adds user entity classes, making the autonomous service invocation capability of the Internet of Things The types of information entities that can actually be carried. The IoT information model constructed here is generally consistent with the IoT information model constructed by IoT-A, except that the IoT information model constructed by IoT-A is mainly for virtual items (corresponding to the figure The information model constructed by the physical entity class of 2) is equivalent to the entity class of Internet-connected items, item data, and item services instantiated on the far left side of Figure 2, and does not include the user entity class. IoT-A mainly focuses on Internet-connected items. The information model can guide the development of IoT application software, but it cannot guide the formulation of the IoT architecture reference model and other IoT technical standards. The information model can guide the formulation of IoT technical standards. Based on the IoT information model, it can The following conclusions are drawn related to IoT technology standards:
(1) The information model of the item itself does not belong to the technical standard scope of the Internet of Things. It can be seen from the information model that the Internet of Things only collects item data, and how to convert the item status and behavior into item data does not fall within the scope of the Internet of Things processing. , nor does it belong to the scope of IoT technical standards. Information modeling of real items is an issue considered in the application field of IoT-related items.
(2) The basic function of the IoT device is to associate real items and virtual items. Other functions of the IoT device (such as data caching, application agents, etc.) belong to the combined functional entity of the IoT device and other connected devices of the IoT.
(3) Existing network equipment can be used as objects connected to the Internet of Things. The intelligent management technology of existing network equipment can be applied to the Internet of Things. The Internet of Things can use existing network management technology to connect and sense existing network equipment (such as the Internet of Things). devices, routers and servers, etc.).
(4) Machine-to-machine communication (M2M) services are part of the Internet of Things communication services. The technical standards of the Internet of Things communication services need to be developed in consultation with the M2M service technical standards.
(5) The IoT information model includes the resource entity classes of existing network elements. Therefore, existing network elements can be included in IoT resource management, and the virtualization technology of existing network element resource management can be applied to the IoT. IoT resources Management technology standards need to be formulated in consultation with existing virtualization technology standards for network element resource management. These conclusions about IoT technology standards can largely clarify many controversial technical issues in the formulation process of IoT technology standards.