Web services and workflow: composition, collaboration, coordination

Many researchers are becoming interested in how the standards associated with the World Wide Web can facilitate machine-to-machine communication. Standards associated with Web services provide mechanisms for machines to discover resources and invoke services across the Internet. One potential use of these standards is in the coordination of long-running processes across organizational boundaries. Instead of simple request-response patterns, these processes require the elaborate sequencing of messages, the discovery and binding of service access points, and the consideration of decentralized process control. This article introduces the following topics: Web services composition in an open environment; human intervention as an important aspect of any complex distributed system; and the grid in workflow systems and management.