The Design And Implementation Of Distance Education Oriented Search Engine System

Distance education-oriented search engine is one way to locate e-learning resource. In crawling stage, this paper first analyzes the educational resources construction mechanism, and designs the private data structure, then solves the problem of DNS resolution, unified coding and so on. A crawling mechanism based on address section control and content graph control is proposed, which makes the crawling efficiency increases by 36.1%; In preprocess and indexing stage, through analysis of lex technology, this paper designs a web content extractor based on lex, proposes a word-length adaptive Exclusive-OR hash algorithm, constructs the educational dictionary, causes the conflict rate reduced to 0.03%, and depends on this constructing the index system; Finally, on the base of information retrieval basic theory and retrieval model analysis, this paper proposes a distance education oriented information retrieval model, completes the search through the user interface to retrieval subsystem, and introduces the caching strategy for enhance the retrieval efficiency, which cause 80% search is zero-retrieval in distance education field. The experiment indicates that the implementation of the subsystems meet the accuracy rate request under the recall rate achieved in vertical search engines, application of the system has brought good results.