Poster on transparent access to a network of information sources and service providers via a universal relation interface

Summary form only given. We propose the use of the universal relation as a user interface to provide transparent access to a network of distributed, heterogeneous, and autonomous information sources. We implement this interface in two layers. The lower layer consists of access scripts, which encapsulate knowledge about information sources and are capable of answering basic queries. The upper layer uses combinations of these scripts to answer user queries phrased in terms of a universal relation. In this paper we address the problem of defining the semantics of a user query posed against the universal relation and of finding a sequence of access script invocations that gathers the information requested in the query