Design And Implementation Of Remote Supervision Subsystem In Paperless Examination System

With the rapid development of network technology, the system of paperless examination begins to be widely adopted. Thanks to the particularities of paperless examination, the application of remote supervision in such system is conducive to the successful fulfillment of the invigilation. Therefore, it is significant to design and achieve a remote monitoring system which has satisfying function and is prepared for paperless examination system.Combined with specific practical requirements, the designing of remote monitoring subsystem for paperless exam is illustrated. Besides, the overall designing principles are provided and the basic framework of subsystem, division of modules and the working processes of every function modules of the subsystem are described.Three supervising methods are introduced in details, namely, remote screen monitoring, monitoring via keyboard operation, and remote process monitoring. In this thesis, the following objects in remote screen monitoring are mainly discussed: the technology of screen capture, image encoding and decoding, the simulation of mouse, keyboard operation, and the application of low-layer keyboard hook. Meanwhile, the implementations of real-time monitoring to candidates'state are provided.The realization details of data communications in the subsystem are focused on. In addition, an application layer protocol based on TCP/IP is proposed, in which the data transmission is carried out via message transmission and the definition of the structure of messages is explained. In order to improve the system's performance to respond a number of I/O requests, Windows completion port is chosen to handle data I/O. And the designing of a data communication model based on completion port is illustrated. In addition, how to deal with special circumstances in the process of data transmission and reception is mentioned. Moreover, the ways concerning about how to transmit a number of data in data transmission and to handle emerging messages debris while receiving data are explained in detail.Actual application has proved that this designed remote monitoring subsystem can assist invigilators fulfill their remote invigilation in reality effectively, which can not only reduce their working burden, but also avoid cheating in some extent.