Research on the classification system and performance evaluation-yahoo of search engine yahoo

At present, many search engines combine the task of organizing the Network information resources through the combination of the key words such as the hierarchical topic catalogue and the keywords provided by the computer retrieval software. Yahoo is the typical representative of this class-style theme-Guide search engine.
　
Yahoo's charm lies in its browsable ranking theme index. Based on the theme of the classification index, providing a comprehensive classification architecture, combined with high-quality search software, Yahoo successfully established a unique information management and organization mechanism, so that the comprehensive search of network information into reality. This paper makes a further discussion on Yahoo's class-target system, classification principle, retrieval method and performance evaluation.
First, the category system
Yahoo consists of 14 basic categories, including art&humanities (arts and Humanities), Business&economy (Business and Economics), Computers&internet (Computer and Internet/Network), education (education), Entertainment (Entertainment), government (government), Health (Health and Medicine), News&media (News and media), Recreation&sports (leisure and sports), Reference (Reference), Regional (country and region), Science (Sciences), Socialscience (Social Sciences), Society&culture (Society and Culture).
Depending on the information or the size of the Web site and the needs of the knowledge organization, each basic class is subdivided into different levels of sub categories or subcategories, and the more specific the subject of the site in the sub category. It establishes a fairly detailed directory hierarchy of categories, such as the class head, subclasses, and so on. Its class head design is reasonable, the structure is complete, comprehensive, the class order hierarchy is distinct, the level detail, the broad degree is different, thus provides the foundation for the online rich information resources classification, especially the exact classification.
Ii. Principle of classification
Internetscoutproject's classified expert, Aimeeglassel, said, "There is a close link between the famous classification experts in India and the library experts Yangang Nazin's system of colon classification and the main catalogue of Yahoo Network information resources", Thus revealing the Yahoo application faceted analysis side
The essence of the classification of Network information resources by law. Specifically, the following points can be a deep understanding of Yahoo's faceted classification principle or basic process.
1. Use of broad thematic areas to establish a classification index
In order to make its classification system not only has the infinite accommodating, but also has the quite specially specifically, the Yahoo uses the relatively broad topic domain, through the analysis and the synthesis method to establish the comparatively complete classification index. This is consistent with the idea of faceted classification, because dividing knowledge into a broad class-like facet, reflecting the subject content in many ways to avoid the linear one-way structure of enumerated class tables is the main principle of the Yangang Nazin colon taxonomy.
2. A combination of information content based on context
From the Yahoo's classification structure looks, may think it and thesaurus very close, because Yahoo also uses the vocabulary rather than the symbol to compose the corresponding concept word string. However, it is far more complicated than the common thesaurus to look at the ability of the combination. By analyzing the content characteristics of a Web page, you have to