Research On Retrieval Of Multimedia Network Teaching Resources In Elementary Education

The education informalization has brought transformation of the concept of educational thought, making the new requirements to both of teachers and students. The teachers should possess to utilize the network to obtain teaching resources, and to organize teaching, as well the students should have the ability of taking advantage of the network to carry on the self-learning. Although there are abundant information resources in the Internet, the available teaching resources are scatteredly distributed and the quality is very different. While existing WEB search engine function has improved day by day, but the majority adopts methods based on the keyword, which is powerless in the retrieval of multimedia resources. Therefore, it is necessary to find out a more convenient and efficient system to assist in the multimedia resources retrieval, especially for the teachers and students of primary and secondary schools, who are lack of computer capacity relatively.On the basis of above reasons, we have established a basic education-oriented index database of multimedia resources, by organizing the pre-search keywords of basic education and searching network resources. Regarding the teachers and students of primary and secondary schools as its main users, the resources index database is exactly based on their textbooks. Furthermore, a multimedia resources index database retrieval system which faces the basic education has been built up, with the support of the ASP technology.Organizing the elementary education pre-search keywords, as preparatory work of the establishment of the basic education-oriented multimedia resources index database, is intent to provide searching direction for the pre-search system. Based on the textbooks of primary and secondary schools, through manually collection and sorting, we built up a thematic words system of basic education from three perspectives, i.e., stage, subject and type. From the aspect of stage, we discussed primary school, junior middle school and senior middle school periods, while there are 5, 12, 14 subjects concerned with each stage respectively. Also, the thematic words are divided into types of image, animation, video and audio.In this thesis, we design and establish a retrieval system that based on the basic education-oriented multimedia resources index database. This is a web-oriented retrieval system, which can create a connection to the WEB multimedia resources index database according to each username. Each resource database contains four types of resource: image, animation, video and audio. User log-in interface, user input interface, search result output interface are included in this system. Analyzing the type, characteristic and storage feature of the media, the retrieval system adopts a method of Chinese natural language query, to measure the difference between the object media and media in the database by means of similarity.The natural language is the effective tool to express thoughts, using which to describe the semantics of multimedia resources will be a simple and effective method. This thesis introduces the general ways of word segmentation on the natural language, builds our own word segmentation algorithm from the existent segmentation dictionaries, to divide the query texts and label its parts of speech (POS) tagging. After obtaining the thematic words such as nouns, verbs, adjectives and idioms by omitting the function words and the default words from the query texts, we can get the description of the object media and call them"theme content". The theme content should be extended according to the synonym dictionary before calculating the similarity.The media resource index database includes medias of four types of image, animation, video and audio, and the thesis adopts the similarity to measure the difference between the object media and media in the database. The media features include text features and content features, between which we mainly refer to the latter while calculating the similarity. As to different content features, different technologies will be used to calculate the similarity. The similarity is obtained by finding the number of same words between the extended theme content and the content description field in the database. The color word of the dominant hue is changed into HSI model, and then the similarity calculation of the tone with the dominant hue field marking in the database by way of numerical value could be carried on. The subject and subject attribute of the picture are calculated similar degree to the subject field in the database. After confirming the importance of the content features according to their level, calculate the total similarity. The records whose total similarity is greater than a certain threshold value will be recorded from great to small order according to total similar degree, and finally feedbacked to users as searching result.Based on the work described above, a large number of experiments to the retrieval system that based on the basic education-oriented multimedia resources index database have been carried on, and detailed statements to the experimental result have been presented. The experiment showed that, with the relatively simple and less nested query texts, the retrieval system is able to provide pretty accurate words segmentation, detailed and accurate record to the content feather in the database, and the search results of higher accuracy, proving that the method to search according to the content characteristic is feasible. The shortcoming is that with the increase of recording in the multimedia resource index database, or when there are relatively more searching conditions, the system operation slows down. Finally, the thesis summarizes the main conclusion and puts forward the next research direction.