McIlraith, KSL Stanford April 11, 2003

Semantics Web Services Language:Scope and Objectives

Sheila McIlraith

Knowledge Systems Lab, Stanford University

April 11, 2003

McIlraith, KSL Stanford April 11, 2003

Context

Context dictates what we can do and how we should do it:• Fast-paced industry initiative on Web services• Minimal interest in “semantic” web issues

McIlraith, KSL Stanford April 11, 2003

How?

Must integrate with and complement industry efforts

• Convince mainstream of the merits/value-added of SWS– demonstrate value-added through demos of “cool apps”– facilitate adoption of SWS through development of tools– integrate with existing standards

• Lead and influence standards efforts rather than try to re-engineer them.

McIlraith, KSL Stanford April 11, 2003

What?

Let the applications, unique to Semantic Web Service drive language development

McIlraith, KSL Stanford April 11, 2003

Applications: Automation TasksAutomation of:• Web service discovery

Find me a shipping service that will transport frozenvegetables from San Francisco to Tuktoyuktuk.

• Web service invocation Buy me “Harry Potter and the Philosopher’s Stone” at

www.amazon.com

• Web service selection, composition and interoperation Make the travel arrangements for my WWW11 conference.

• Web service execution monitoring Has my book been shipped yet?

Web service mediationWeb service simulation and verification

McIlraith, KSL Stanford April 11, 2003

Observations

• DAML-S is appropriate for WS discovery and invocation

• DAML-S + Rules (or the like) may be sufficient for WS interoperation, semantic translation

• Need something more expressive (and different) for composition, complex mediation, simulation and verification. Partially addressed by industry initiatives such as XLANG, WSFL and BPEL4WS.

McIlraith, KSL Stanford April 11, 2003

Language Desiderata (incomplete)

• Declarative

• Compositional

• Well-defined semantics

• Understandable & usable (tools)

• Amenable to automated reasoning techniques

• Not just interface descriptions, but functional and behavioral specifications of component software

• Integrated with existing industry standards XML, SOAP, WSDL, BPEL(?)

• Addresses both the KR and PL aspects of WS.