Research On Retrieval Of Network Multimedia Educational Resources Database

The society develops continuously, and it makes increasing demands on education. As a modern teaching method, multimedia instruction has promoted the informatization, reform and development of education actively and effectively. Multimedia educational resources are necessary for the application of multimedia instruction. At present, the Internet has become the biggest library of multimedia educational resources. Search engines are people's good helpers when they try to obtain information from the Internet. However, most general search engines are based on keywords, and they are not very efficient in searching for a variety of teaching and learning media more often than not. After studying content-based retrieval of multimedia, this paper improvs a retrieval system of network multimedia databases in elementary education, with a view to provide teachers, students and other related users with efficient, professional retrieval service of network multimedia resources.This paper organizes multimedia keywords according to primary and secondary school textbooks, and then searches and downloads multimedia educational resources from the Internet. Then, it analyses and extracts the properties of those multimedia resources, and establishes index databases of multimedia educational resources. It does some research on content-based retrieval of image, flash, video and audio databases, and develops a retrieval system of network multimedia educational resources database with ASP.The retrieval system is the main content of this thesis. At the beginning of retrieval, the system deals with content and color descriptions of target media. This paper brings forward a new algorithm for Chinese word segmentation - fast and two-way algorithm, and develops a Chinese word segmentation module to split the text of content description. After that, the system filters out useless words and finally gets the key information of content description. On the other hand, the names of colors in color description need to be converted to values of HSI color model.Image, flash, video and audio have their own characteristics and properties. The retrieval system sets retrieval conditions, which correspond to the main fields of multimedia database tables, according to the main properties of multimedia. Similarity is used to measure the gap between target media and library media. The system calculates similarities between target media and library media by comparing query information and the values of corresponding fields. Different conditions have different methods of similarity calculation. There are some simple retrieval conditions, such as format and size. As for these conditions, the system calculates by means of Boolean, that is, the similarity is 1 only when target media and library media match strictly, and otherwise it is 0. As for the other conditions, such as content and color, the system calculates by means of fuzzy. Different conditions have different methods of fuzzy similarity calculation. The total similarity of multimedia is the product of each similarity of multimedia.In order to improve the efficiency of the retrieval, the system indexes content fields of the tables of multimedia databases. The use of index speeds up the retrieval of multimedia content description. Before the system provides results to users, it puts results into cache. The use of cache can reduce the time of pageing. In addition, this paper discusses how to improve ASP's efficiency and program codes are improved.Users describe target media and give retrieval requests after they log in. Then, it is up to the retrieval system to deal with query information automatically, and then compute similarities of library media. At last, results are provided to users, including previews, similarities and other related information. As is shown by experimental results, as for those records whose index information is accurate and detailed, the results of has higher accuracy. At the same time, the use of index and cache speeds up the retrieval obviously.