McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Mobilizing the Web with

DAML-Enabled Web Services

Sheila McIlraith

Knowledge Systems Laboratory (KSL)Department of Computer Science

Stanford University

(with Son Cao Tran and Honglei Zeng)

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Motivation

The Web is evolving from a provider of documents

and images …

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Motivation

… to a provider of services

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Overview

Problem: today’s web is designed primarily for human use.

We are developing semantic markup of • web services,• web service users’ preferences and constraints• reusable agent procedures

to make services computer-interpretable, use-apparent, and

agent-enabled.

We are developing agent technology that exploits semantic

markup to support automated web service discovery,

execution, composition and interoperation.

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Web Service Markup Will Enable

Automation of:

• Web service discoveryFind me an airline service that offers flights to Tuktoyuktuk

• Web service executionBuy me “Harry Potter and the Sorcerer’s Stone” at

www.amazon.com

• Web service selection, composition and interoperationMake my travel arrangements for my IJCAI conference trip

Industry efforts growing

(we are improving with DAML)

Opportunity Area

These are the drivers for web service markup.

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Framework

DAML-enabled web pages

Web Service Ontologies

Web Procedures Ontologies

AgentBroker

E-mail

DAML-enabled personal/company

constraints and prefs...

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Key Feature: DAML Markup of Web Services Function, Action, Process-based web service markup:

• declarative • well-founded semantics Ontologies enable:

• reuse • sharing• composition • succinct web site markup

E.g.,service world-altering service purchase purchase-plane-ticket

purchase-UAL-plane-ticket parameters: c-name, origin, dest, d-date, … preconditions: know(c-name), valid(credit-card), … effects: purchased(ticket), debit(credit-card)... rent rent-car ...

Web Service Ontologies

DAML-enabled web pages

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Key Feature: Generic Procedures

Agents are tasked in terms of high-level, reusable “generic procedures.”

“The what not necessarily the how.”

Ontologies support sharing,reuse, and composition.

DAML-enabled web pages

Web Service Ontologies

Web Procedures Ontologies

AgentBroker

E-mail ...

E.g.,Travel(cust,origin,dest,date-d,date-r,purpose) Check-purpose-related-restrictions; Book-travel(origin,dest); Book-transportation(dest); Book-hotel(dest)end;

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Key Feature: Customizing Generic Procedures

Generic procedures can be further constrained by

DAML-defined constraints• user constraints/preferences, • group constraints, or• instance-specific constraints.

DAML-enabled web pages

Web Service Ontologies

Web Procedures Ontologies

AgentBroker

E-mail

DAML-enabled personal/company

constraints and prefs...

E.g., • Bob would like to drive if the driving distance is less than3 hours.

• KSL Business air travel should be on an American carrier.

...

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Key Feature: Deductive Instantiation

Agent’s KB is automatically constructed relative to the

generic procedure and constraints. KB is updated by web

service responses.

Deductive machinery instantiates the generic procedure

wrt. constraints and world state to

generate web service requests

that the broker executes.

KB

Web Services

Service Ontologies

Procedures Ontologies

AgentBroker

Constraints & Prefs

E-mail ...

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Status

DAML = First-order logic and some DAML+OIL

Agent KB representation language = Situation Calculus

Generic procedures representation language = Golog

Deductive machinery = Prolog

Agent Broker = Open Agent Architecture [SRI]

Prototype agent/agent broker constructed.

Preliminary service ontology constructed.

KB

Web Services

Service Ontologies

Procedures Ontologies

AgentBroker

Constraints & Prefs

E-mail ...

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Come to Our Demo!

Teaser: Dynamic User Interface with DAML+OIL

McIlraith - Knowledge Systems Laboratory DAML PI Meeting 02/14/2001

Possible Discussion Topics

• What language expressive power do we need? (Let’s help drive language development.)

• What collective tools do we need? (Let’s coordinate and share the effort.)

• How do we interact with each other?

• How do we interact/leverage with industry efforts?

• ...