Research On Data Extraction And Visualization For Distributed Railway Track Monitoring

With the increasing speed of existing line and development of high speed railroad, there is urgent need for the adoption of effective techniques to take longtime railway track inspection and monitoring. Distributed sensor networks are perceived as an intelligent technique for collection, aggregation and integration of long-term basis monitoring data for railway track, whose installation space is limited and covering region is wide. Based on the needs of visualization for distributed data, the data extraction and visualization system and history monitoring data scan tool based on smart mobile terminals are designed and implemented in this paper.The overall design of data extraction and visualization system is realized. On the basis of analysis of monitoring requirements, the system use case model is established, and the three-layered architecture consisting of presentation layer, business layer and data layer is built. Modular package according with the functionality of the system is carried out. The overall work flow is designed according to the functionality. Then, outline design of the main interface is accomplished in view of the relationship among the framework, the measuring point distribution and the data display window.The key functional modules of the system are designed and realized using object-oriented programming techniques. Mainstream relational database MS SQL Server is put into use for monitoring database, and a table with file store mode is used for sample data taking into account its large volumes single-sample and long sampling interval. And ADO-based database interface is implemented. Using development kit GDI and VTK, measuring point distribution and data visualization are finished. In addition, a multi-threaded real-time monitoring process is established to improve the multi-task processing capabilities for database interaction, data extraction and data visualization.The history monitoring data scan tool based on Android platform and Web service schema is designed and realized. A Web server is set up using Apache and accessing SQL Server script file is programmed by PHP. The interface and functionality of login to the database, history monitoring data extraction and showing are designed and implemented using Android’s controls and AChartEngine components. The data extraction and visualization system and the history monitoring data scan tool are successfully applied to a rail stress monitoring experiment. The application shows that the system and tool presented in this paper just fulfill the data management, extraction and visualization needs for distributed railway track monitoring, verify the feasibility and practicality of the design proposal in this paper, and have important practical significance for using of distributed sensor networks in the railway track monitoring.