Research On Architecture And Key Technologies Of Internet Of Things Access System

With the development of the Internet of Things(IoT)technologies,more and more industries become the new application fields of IoT.In the face of numerous and heterogeneous devices in IoT,how to provide the unified access method for those devices is a key and difficult issue.To address this,many scholars at home and abroad have proposed different designs to deal with this,but most of them meet kings of problems: On one hand,most of the traditional designs take high resource while have limited access capability,which makes the system too expensive.On the other hand,the architecture and data format of different designs are heterogeneous,which makes the system are incompatible with each other.Therefore,how to realize the unified access for various things in IoT with existing technologies and designs has important practical significance.To address the above problem,we start our research from the access features analysis of things in IoT,and discuss the functional and non-functional access requirements for those things.Based on this,we carry out the detailed research on the common unified access project including the key technologies for things to access to the IoT.Based on the above ideas,we propose the IoT access system(IoTAS)for the ubiquitous things on the first time.The access system can shield the heterogeneity of the underlying devices,and realize the unified hardware access and function publication.In order to implement the access system,we propoe the complete architecture including the overall architecture,physical architecture,software architecture and key technology architecture.Based on this,we make in-depth and detailed studies on the access system from hardware interface,resource description,resource publication,etc.The major contributions of this dissertation are stated as follows:(1)Provide the complete architecture of the IoT access system.Based on the access features analysis of things in IoT,we proposed the functional and non-functional access requirements.Based on the current access strategies,we proposed the overall architecture of the IoT access system.Besides the proposed software,hardware and key technolygies architectures,the hybrid physical structure and multi-agent software architecture are discussed in detail.(2)Propose an IEEE 1451-based expanded hardware interface for the IoT access system.This interface is based on the IEEE 1451 standard which can support various sensors and actuators.Besides,the interface can realize the access of the high-speed devices and the novel devices with the FPGA,IP cores design and multiplexing technologies.Based on this,a multi-functional IP core is designed and implemented for various 1-wire actuators.(3)Propose an ontology-based resource description model for IoT(ORDM).Based on the analysis of current description models,we build the domain model for devices in IoT,and further propose the ORDM in detail.Based on attributes,interfaces,status and function dimensions,we realize the comprehensive resource description for IoT access devices.(4)Propose a service publication method based on REST,which realizes the unified resource publication for IoTAS.We design and implement the basic resource(BR)based on the ORDM,and further design the combined resource(CR)and role-oriented resource(RR)according to different types of resources.Based on the RESTful API design for kinds of resources and business publication implementation,we realize the unified function publication for things in IoT.(5)Propose a resource-oriented scheduling algorithm for IoTAS to solve the multi-user random resource access,and further improve the efficiency of the IoTAS resource publication.Based on the formal description of the IoTAS resource publication scheduling problem,a resource-oriented non-preemptive EDF scheduling algorithm is proposed and verified by simulation experiments.This dissertation focuses on the access problem for things in IoT,and proposed IoT access system architecture and key implementation technologies.Combining the practical application requirements,we develop and apply some typical IoT applications such as the smart office.Based on the overall analysis and evaluation for the access system,it is verified that the proposed IoT access system can meet the functional and non-functional demand for things in IoT,and implement the unified IoT access for various things in different applications,which has good application and dissemination value.