4) The Complexity of Queries and Query Results
The basic paradigm supported by Search Engines to locate WWW resources is based on traditional information retrieval mechanisms, i.e., keyword-based search and simple boolean
expressions. This functionality is supported by indices and dictionaries created and maintained at the back-end of a search engine with the help of information retrieval techniques. Given
that the expected difficulty of queries ranges from that of very small enquiries to requests requiring complicated joins, intelligent-agent interfaces are required to help users formulate
queries and the search engine to compute efficiently those queries. Of equal importance is the presentation of query results within a representative conceptual context of the Grid,
so that users can navigate within the complex space of query results via simple interfaces and mechanisms of low cognitive load.