Mobilizing the Web with DAML-Enabled Web Services

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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)

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Motivation
The Web is evolving from a provider of
documents and images
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Motivation
to a provider of services
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Overview

• Problem todays 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.

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Web Service Markup Will Enable

• Automation of
• Web service discovery
• Find me an airline service that offers flights to
  Tuktoyuktuk
• Web service execution
• Buy me Harry Potter and the Sorcerers Stone at
  
• www.amazon.com
• Web service selection, composition and
  interoperation
• Make my travel arrangements for my IJCAI
  conference trip

These are the drivers for web service markup.
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Semantic Markup

• How is DAML adding value over XML?
• Ontologies
• reuse sharing
• composition succinct web site markup

E.g., service world-altering service
purchase purchase-plane-ticket
purchase-UAL-plane-ticket
purchase-book ... Information-providing
service provide-schedule-info
provide-flight-schedule-info ...
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Semantic Markup

• How is DAML adding value over XML?
• Ontologies
• reuse sharing
• composition succinct web site markup
• Constraints and Rules
• compact representation
• ease of expression

E.g., flight-over-3hours ? movie unauthorized-web-
site ? unreliable-source
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Semantic Markup

• How is DAML adding value over XML?
• Ontologies
• reuse sharing
• composition succinct web site markup
• Constraints and Rules
• compact representation
• ease of expression
• Semantics

E.g., supplier -vs-
vendor due-date
due-date
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Web Services An Example

• Web service discovery
• Find me an airline service that offers flights to
  Tuktoyuktuk
• Web service execution
• Buy me Harry Potter and the Sorcerers Stone at
  
• www.amazon.com
• Web service selection, composition and
  interoperation
• Make my travel arrangements for my IJCAI
  conference trip

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Approach

• Each web site provides a set of services
• information providing (e.g., flight schedules,
  camera views) or
• world-altering (e.g., booking flights, home
  temp. adjustment)
• Web services are conceived as
• functions for execution, (Declaratively
  Specified API)
• actions/processes for composition and
  interoperation.
• Web sites are annotated with DAML markup,
  describing
• services in terms of action preconditions
  
• and effects or in terms of processes of
• actions.

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DAML Markup of Web Services
Function and action-based markup exploits
ontologies
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
... Information-providing service
provide-schedule-info
provide-flight-schedule-info ...
Collectively they create a distributed KB of
services.
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Agents request services through brokers
Agents communicate with DAML-enabled web sites
through Agent Brokers that request web services
and dispatch responses. Brokers exploit the web
service ontologies to assist in locating
appropriate service providers.
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DAML-Enabled Agents
Agents are tasked by people, or by other
agents.
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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.
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Customizing Generic Procedures

• Generic procedures can be further constrained by
• DAML-defined constraints
• user constraints/preferences,
• group constraints, or
• instance-specific constraints.

E.g., Bob would like to drive if the driving
distance is less than 3 hours. KSL Business
air travel should be on an American
carrier. ...
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Instantiating Generic Procedures
Agents 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.
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Status

• DAML First-order logic and some DAMLOIL
• 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 ervice ontology constructed.

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Travel Example
Bob Chen wants to travel from San Francisco to
Monterey, departing September 2 and returning
September 6. The purpose of the travel is DAML.
Generic Procedure Travel(customer,origin, dest,
date-d, date-r, purpose) Book-travel(origin,d
est) Book-transportation(dest)
Book-hotel(dest) Inform(customer)
Create-expense-claim end
Our Labs Relevant Constraints KSL Business air
travel must be on an American carrier. Bobs
Relevant Constraints Bob would like to drive if
the driving distance is less than 3 hours.
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Dynamic User Interface with DAMLOIL
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Behind the Scenes

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Behind the Scenes
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Behind the Scenes
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Behind the Scenes
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Behind the Scenes
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Behind the Scenes
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Behind the Scenes
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Behind the Scenes
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Agent e-mails itinerary to customer

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Agent e-mails itinerary to customer

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Agent e-mails itinerary to customer

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Agent e-mails itinerary to customer

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Agent e-mails itinerary to customer

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Agent creates expense claim for customer

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Summary of Key Features of KSL Work

• DAML Markup of Web Services, User Constraints,
  Agent Procedures
• Computer-interpretable, use-apparent,
  agent-enabled services.
• Ontologies facilitate construction, sharing,
  reuse, and composition
• support succinct web site markup.
• Markup not specific to particular agent
  implementation.
• A DAML-Enabled Agent System
• DAML markup provides distributed KB for agents.
• Logic-based generic procedures constraints.
• Procedures - general and easy to use.
• Constraints enable customization.
• Ontologies facilitate construction, sharing,
  reuse, composition.
• Procedures are verifiable wrt. certain
  properties.
• Deductive machinery instantiates procedures
  generating
• web service requests that are sent to the agent
  broker.
• Procedures deductive machinery provide middle
  ground
• between planning programming.

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Take-Away Message

• Semantic Web Services are going to
  revolutionize B2B and E-Commerce on the Web.
• They will also revolutionize the way companies
  deal with their information and business
  processes.
• Semantic markup (DAML markup) of web services
  is the key enabling technology for this
  revolution.