DISCOVER - A RESOURCE DISCOVERY SYSTEM BASED ON CONTENT ROUTING

We have built an HTTP based resource discovery system called Discover that provides a single point of access to over 500 WAIS servers. Disco ver provides two key services: query refinement and query routing. Que ry refinement helps a user improve a query fragment to describe the us er's interests more precisely. Once a query has been refined and descr ibes a manageable result set, query routing automatically forwards the query to the WAIS servers that contain relevant documents. Abbreviate d descriptions of WAIS sites called content labels are used by the que ry refinement and query routing algorithms. Our experimental results s uggest that query refinement in conjunction with the query routing pro vides an effective way to discover resources in a large universe of do cuments. Our experience with query refinement has convinced us that th e expansion of query fragments is essential in helping one use a large , dynamically changing, heterogenous distributed information system.