Research On The Sensor Network-based Monitoring System Model And Key Technologies

With the rapid development of sensor technology, embedded technology, network communication technology and software engineering technology, the sensor network-based monitoring system is widely adopted in the field of environment protection, medical observation, industrial manufacturing, and so on. It mainly includes the sensors, data acquisition devices, computer and supervision software, which is used to automatically acquire, manage, analyze, and present the data for the end users. This paper proposes the system layered model, and studies the key technologies in terms of target tracking, data collection, software development and system integration. Specifically, our major contributions are as follows:1. This paper proposes a reference model for the sensor network-based monitoring system. Due to the lack of a normalized system design criteria, there are many troubles in the process of system development and data sharing. By analyzing multiple sensor network-based monitoring systems, we present a universal reference model. According to the data flow, the monitoring system is logically composed of a hierarchy of layers, which are the sensing layer, the collection layer, the management layer, and the application layer, respectively. Moreover, the model specifies the layer functions and interfaces between layers. The building of the model can improve the software development efficiency and facilitate system integration. The whole layered model serves as a foundation for this paper.2. In the sensing layer, mobile target tracking with wireless sensor networks is studied. And a bubble trace (BT) algorithm is proposed for tracking target under insufficient anchor coverage. Existing tracking schemes are mainly based on trilateration, which requires each point in the monitoring area to be covered by at least three anchors. However, due to the inadequate deployment of costly anchors and environment constraints, the target might not always be detected by three or more anchors simultaneously, resulting in intermittent localization failures and performance degradation. By fully extracting the location information embedded in dual, single and zero anchor coverage, we develop a bidirectional bounding algorithm to offer the bubble-shaped regions that indicate the possible locations of the target. Moreover, instead of separately estimating each position point of the target, we construct the trace by finding a maximum-likelihood path in a graph. The design is evaluated through extensive simulation and a test-bed experiment with 20 MicaZ nodes. Results show that the proposed scheme improves the tracking accuracy without using additional hardware under insufficient anchor coverage.3. In the collection layer, the data collection problem under heterogeneous sensing hardware is studied. And a configurable data collection middleware (DCM) is proposed. The diversities of data format, communication command and hardware interfaces make upper development difficult. DCM hides the lower layer complexity by providing the uniform resource primitives and normalized data format. In addition, we adopt the XML to describe the sensing equipment information. When adding or removing some acquisition devices, DCM can still run normally by re-configuration without recompiling. Based on the DCM, the designer can more focus on upper application development without knowing hardware details. The prototype system shows that the proposed DCM is feasible and effective and has good scalability.4. In the management and application layer, the upper software development problem is investigated. And an interactive software development platform (ISDP) is proposed. After obtaining the original sensing data, they have to be managed and displayed by a friendly application for further analysis. In order to improve the software development efficiency, this paper designs the ISDP, which consists of the reusable component libraries, the data collection subsystem, the assembly subsystem and the customization subsystem. The software development process is turned into configuring parameters through interactive dialog boxes. Moreover, the client-based software based on the Client/Server architecture and the web-based software based on the Browser/Server architecture can be developed concurrently. Finally, the development efficiency and the performance of the software generated by ISDP are evaluated. Moreover, the platform is validated by various development cases for manufacturing enterprises. Results demonstrate that the platform remarkably improves the development efficiency and software quality.5. Based on the layered model, the integration standard of monitoring systems is further studied. By analyzing the monitoring systems, the data information and display configuration information are firstly extracted for a monitoring object. Then the system integration architecture is proposed based on the service-oriented model, which mainly consists of local monitoring subsystem, integration management subsystem, system configuration subsystem, integration monitoring subsystem, local monitoring services and integration monitoring services. In the proposed architecture, the local monitoring services are responsible for publishing the monitoring data, while the integration monitoring services take charge of configuration information publishing, achieving the aim of separating the data and display interfaces. As the service consumer, the integration monitoring subsystem calls the two types of web services to display the data from different monitoring system in a unified interface. Through the prototype verification in the household appliances and ocean monitoring fields, the proposed integration architecture has shown good flexibility. In addition, the proposal about the design criterion of integrated test applications for household appliances is approved by IEEE Standards Association.The sensor network-based monitoring system has good reliability, flexibility and a high degree of automation. It has a broad application prospects. With the continuing research on the sensor networks, especially the rising of the Internet of Things technology, it will have a good support to the sustainable economic development.