Agents and Semantic Services: A Critical Review

Abstract

Web Services have been hailed as the latest silver bullet for enabling business process representation and integration. In recent years, industry has developed a variety of standards, e.g. SOAP, WSDL, UDDI, BPEL for web services discovery, description, and distributed execution over the Web. These industry standards have emphasized description of service interfaces. However, they have many limitations with respect to flexible interaction and interoperability among heterogeneous services. For example, WSDL does not give any indication on the order of message exchange between a service and its client.

On the other hand, Multi-Agents Systems research over the years has developed techniques for autonomous and goal-directed agent interactions, agent communication languages that support extended conversations, flexible automated agent discovery in open environments, agent negotiation and methods for peer to peer reactive and proactive agent behaviors in dynamic environments.

In this talk, I will present requirements and extensions on web services functionality for supporting business processes. Some of these extensions include peer to peer and multi-party interactions, dynamic on the fly-composition of web services, message patterns that go beyond request-response, contracts and service level agreements. In addition, I will present characteristics of agents and web services that encourage fruitful application of techniques from agents to services and vice versa. In particular, I will articulate the importance of formally specified, unambiguous semantics for increasing service interoperability and flexibility of interactions, thus bringing the services and agents paradigms and technologies closer to one another. A first step towards this rapprochement is the development of formal languages and inference mechanisms for representing and reasoning with core concepts of Web Services.

In closing, I present my vision of Web services as autonomous goal-directed agents which select other agents to interact with, and flexibly negotiate their interaction model, acting in peer to peer fashion. The resulting Web services, that I call Autonomous Semantic Web services, utilize ontologies and semantically annotated Web pages to automate the fulfillment of tasks and transactions with other Web agents. In cross-fertilizing each other, both agent technology and web services technology can discover new synergies that will make the combination and subsequent adoption much stronger, vital and useful than either of the two technologies separately.