What is Semantic Web?

The semantics Web is envisioned as an extensions of current web there, in addition to being human readable using WWW browsers, documents are annotated with meta-information. This meta-information defines what the information (documents) is about in a machine processable way. The explicit representation of meta-information, accompanied by domain theories (i.e. ontologies), will enable a web that provides qualitatively new level of service

This area encompasses Business Rules, Content Management and Document Management. The business rules approach is primarily finding the rules in such unstructured information, although occasionally business rules also aim to extract similar knowledge from legacy transaction systems. The central idea is that a knowledge engineer, especially coupled with a domain expert, can read great volumes of documentation and organize that documentation in a way that a system could look up what law, rule, regulation, or bit of corporate lore is important at the point of execution, when another member of the organization could use that knowledge if they had it available.

The semantic angle here is twofold. The first is that until we have some semantic consistency and rigor in this process, the product of the knowledge engineer's work will be idiosyncratic. That is, each knowledge engineer will tag things with keywords or terms or whatever they feel are the important ways to index this information at the time they researched it. Furthermore, two terms which are closely related but have different keywords have no way easy way of being cross-associated. So one of the first things to do in an area like this is to develop a rich ontology, which not only will put some structure to the terms to be used, but also indicate which terms are related to other terms.

The second design of this KM System is if the knowledge engineer uses the same or a compatible ontology to that which is being used in the transactional systems, there is a hope for marrying these two systems. There is a great deal of benefit to be gained in doing this. Imagine transactional systems that had tags for hazardous material in their inventory system. That material would be cross-linked to the knowledge management base of what needs to be done: constraints for transporting, storage, reporting, and the like. This is just one tiny example but I believe you can see the point.

The Semantic Web will bring structure to the meaningful content of Web pages, creating an environment where software agents roaming from page to page can readily carry out sophisticated tasks for users. Such an agent coming to the clinic's Web page will know not just that the page has keywords such as "treatment, medicine, physical, therapy" (as might be encoded today) but also that Dr. Hartman works at this clinic on Mondays, Wednesdays and Fridays and that the script takes a date range in yyyy-mm-dd format and returns appointment times. And it will "know" all this without needing artificial intelligence on the scale of 2001's Hal or Star Wars's C-3PO. Instead these semantics were encoded into the Web page when the clinic's office manager (who never took Comp Sci 101) massaged it into shape using off-the-shelf software for writing Semantic Web pages along with resources listed on the Physical Therapy Association's site.

Meaning is expressed by RDF, which encodes it in sets of triples, each triple being rather like the subject, verb and object of an elementary sentence. These triples can be written using XML tags. In RDF, a document makes assertions that particular things (people, Web pages or whatever) have properties (such as "is a sister of," "is the author of") with certain values (another person, another Web page). This structure turns out to be a natural way to describe the vast majority of the data processed by machines. Subject and object are each identified by a Universal Resource Identifier (URI), just as used in a link on a Web page. (URLs, Uniform Resource Locators, are the most common type of URI.) The verbs are also identified by URIs, which enables anyone to define a new concept, a new verb, just by defining a URI for it somewhere on the Web.