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In this tutorial paper we summarise the key features of the multi-threaded Qu-Prolog language for implementing multi-threaded communicating agent applications. Internal threads of an agent communicate using the shared dynamic database used as a generalisation of Linda tuple store. Threads in different agents, perhaps on different hosts, communicate using either a thread-to-thread store and forward communication system, or by a publish and subscribe mechanism in which messages are routed to their destinations based on content test subscriptions. We illustrate the features using an auction house application. This is fully distributed with multiple auctioneers and bidders which participate in simultaneous auctions. The application makes essential use of the three forms of inter-thread communication of Qu-Prolog. The agent bidding behaviour is specified graphically as a finite state automaton and its implementation is essentially the execution of its state transition function. The paper assumes familiarity with Prolog and the basic concepts of multi-agent systems. [ABSTRACT FROM AUTHOR]

In this paper, an agent architecture is proposed that can be used to integrate pre-existing components that provide the domain dependent agent functionality. The key integrating feature of the agent is an active message board that is used for inter-component, hence intra-agent communication. The board is active because it automatically forwards messages to components, they do not have to poll the message board. It does this on the basis of message pattern functions that components place on the board using advertisement messages. These functions can contain component provided semantic tests on the content of the message, they can also communicate with any other component whilst they are being applied. In addition an agent management toolkit, called ALFA, is described which offers a set of agent management services. This toolkit consists of a number of servers for storing the code of the components and symbolic descriptions of what agents regarding their component makeup. A third server uses all this information to facilitate launching new agents. [ABSTRACT FROM AUTHOR]

In this paper, a Multi-Agent System for Distributed Information Discovery and Retrieval is presented. Data mining enables extraction of hypermedia information from heterogeneous information sources existing on the World Wide Web. The goal is to construct a distributed deductive database system of meta-information about these sources using an open architecture and an extensible ontology of descriptive attributes. Each component database is maintained by an information source agent. Prolog-style queries, entered via a user agent, express user requests for information items of interest. The query evaluation is performed utilising intermediary architectural layers of facilitator, matchmaker and descriptor agents that enable intelligent query routing exhibiting co-operative answering behaviour. [ABSTRACT FROM AUTHOR]