Research And Implementation Of Online Examination System Based On Prefetch Cache

With the development of social and the continuous emergence of new knowledge, the traditional training can not meet the needs of knowledge of the people, Network training is hot in the research and application of modern society now. Examination system as the core of the network training module, it's used to test the effectiveness of user's training to ensure effective. Can or not support large-scale concurrent users is a measure of the fundamental quality of an examination system. User data that the server deal with growths fast when concurrent large-scale users take part in the test. So excessive computing is the main deficiency of the exist system. Thus reducing server-side computing data, maximizing the development of client computing power, can improve the quality of service and speed up the response time for users. The prefecth cache is designed for the purpose mentioned above, The main works in this paper are as follows:Analysis the inadequacy of data processing and page shows in the existing system, determine that the important reason of low quality service of the server is that the server-side and client-side do not have cache management of data that accessed from server-side computing, that lead to resources waste. In order to share the server-side computing pressure,we can appropriate develop client's computing power, so that in the concurrent large-scale operation, the server-side used as the role of data distribution and data recovery, the work of data analysis and data match is completed at the client-side, thereby the server can improve the number of users that can be supported.By analyzing the paper and users' answers storage format this paper put forward the client and server-side cache. Taking into account the content of papers is large and the content the users'answers is relative small, therefore the program used is that client caches all the user's answer and some questions, and the work that questions and answers matched is completed at the client-side, and we designed a algorithms for cache. In order to improve the user experience of the system, this article puts forward a strategy for the client pre-fetch. And analyze the behavioral characteristics of the pre-fetch cache to design a algorithms for pre-fech,at last the paper designs a model of pre-fetch cache based on the examination system integration. In order to reduce the loss due to the answer lost in examination process, this paper presents a method to preserve combine save page,save automatically and save manually, and design a algorithms for the save method。In this paper, in accordance with the design thinking of software engineering, describes system usecase model,Sequence Diagram,Class diagram.we carried out needs analysis,system design and system achieve of the basic exam module and the pre-fetch cache module of the examination system. Analysis parts gives the main features of the examination system,the participants role,use cases,the system class diagram and the integration of pre-fetch cache. The general design gives the introduction of the general structure of the system and of the function of the three user modules:administrator, teacher, and student. Design and implementation parts of the exam gives figs of the online-exam system and question, paper management.Finally, the paper introduces the system in the security and performance that achieve, first we analyze the achievement of security in several ways and the corresponding level of administrative privileges, then we apply test to compare performance impact of the use and not use pre-fetch cache system,,and prove that the pre-fetch cache program is effective and practical.