Architectural Issues of Web−Enabled Electronic Business phần 3

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Architectural Issues of Web−Enabled Electronic Business phần 3 Expert Database Web Portal Overview searcher is not expert in developing quality query expressions. Nor, do most searchers select a search engine based on the domain to be searched (Hoelscher & Strube). Searcher frustration, or more specifically a searchers inability to find the information he/she needs, is common. The lack of domain context leads the novice to find a domain expert, who can then provide information in the domain and may satisfy the novices information need. The domain expert should have the ability to express domain facts and information at various levels of abstraction and provide context for the components of the domain. This is one of the attributes that makes him or her the expert (Turban & Aronson, 2001). Because the novice has no personal context, he/she uses the experts context. A domain expert database Web portal can provide domain expertise on the Web. In this portal, relevant information has been brought togethernot as a search engine, but as a storehouse of previously found and validated information. The use of an expert database Web portal to access information about a domain relieves the novice searcher of the responsibility to know about, access, and retrieve domain documents. A Web mining process has already sifted through the Web pages to find domain facts. This Web−generated data is added to domain expert knowledge in an organized knowledge repository/database. The value of this portal information is then more than the sum of the various sources. The portal, as a repository of domain knowledge, brings together data from Web pages and human expertise in the domain. Expert Database Web Portal Overview An expert database−driven domain Web portal can relieve the novice searcher of having to decide on validity and comprehensiveness. Both are provided by the expert during portal creation and maintenance (Maedche & Staab, 2001). To create the portal, the database must be designed and populated. In the typical database design process, experts within a domain of knowledge are familiar with the facts and the organization of the domain. In the database design process, an analyst first extracts from the expert the domain organization. This organization is the foundation for the database structure and specifically the attributes that represent the characteristics of the domain. In large domains, it may be necessary to first identify topics of the domain, which may have different attributes from each other and occasionally from the general domain. The topics become the entity sets in the domain data model. Using database design methods, the data model is converted into relational database tables. The experts domain facts are used to initially populate the database (Hoffer, George, & Valacich, 2002; Rob & Coronel, 2000; Turban & Aronson, 2001 ). However, it is possible that the experts are not completely knowledgeable or can not express their knowledge about the domain. Other sources for expert level knowledge can be consulted. Expert level knowledge can be contained in data, text, and image sources. These sources can lead to an expansion of domain knowledge in both domain organization and domain facts. In the past, the expert was necessary to point the analyst to these other sources. The experts knowledge included knowledge such as where to find information about the domain, what books to consult, and the best data sources. Today, the World Wide Web provides the analyst with the capability of finding additional information about any domain from a little bit of knowledge about the domain. Of course, the expert must confirm that the information found is valid. In the Web portal development process, the analyst and the expert determine the topics in the domain that define the specializations, topics, of the domain. These topics are based on the experts current knowledge of the domain organization. This decomposition process creates a better understanding of the domain for both the analyst and the expert. These topics become keyword queries for a Web search, which will now add data to the experts defined database architecture. 70 Related Work The pages retrieved as a result of the multiple topic−based Web searches are analyzed to determine both additional domain organizational structure and specific facts to populate the original and additional structures. This domain database is then made available on the Web as a source of valid knowledge about the domain. It becomes a Web portal database for the domain. This portal allows future novice searchers access to the experts and the Webs knowledge in the domain. Related Work Web search engine queries can be related to each other by the results returned (Glance, 2000). This knowledge of common results to different queries can assist a new searcher in finding desired information. However, it assumes the common user has domain knowledge sufficient to develop a query with keywords or is knowledgeable about using search engine advanced features for iterative query refinement. Most users are not advanced and use a single keyword query on a single search engine (Hoelscher & Strube, 1999). Some Web search engines find information by categorizing the pages in their indexes. One of the first to create a structure as part of its Web index is Yahoo! (http://www.yahoo.com). Yahoo! has developed a hierarchy of documents that is designed to help users find information faster. This hierarchy acts as a taxonomy of the domain, which helps by directing the searcher through the domain. Still, the documents must be accessed and assimilated by the searcher; there is no extraction of specific facts. An approach to Web quality is to define Web pages as authorities or hubs. An authority is a Web page w ...