Abstract
This paper describes a multi-agent platform to be used for the integration of environmental information that may be distributed over a network. The system is designed to work as a collection of collaborating agents. Information sources are encapsulated as data source agents (DSAs) that accept messages in an agent communication language. Here we describe how queries can be entered into the system and information collected from multiple sources. A key component of the query module is the planner agent, which takes a query and transforms it first to a calculus, then to an algebraic expression in order to break it into subqueries which an executor agent can send to the DSAs. As part of this process, the query is translated from user-level ontologies to lower level ontologies relevant to the DSAs. Query results need not be returned within an ACL message, but may instead be represented by a Common Object Request Broker Architecture (CORBA) object reference which may be used to obtain the result set. The architecture and operation of these agent components is described and an example is presented of how environmental information can be queried. (C) 2003 Elsevier Science Ltd. All rights reserved.