DAML-S: Accessing Information and Services on the Web

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DAML-S Accessing Information and Services on the
Web
Mark Burstein, BBN Technologies (burstein_at_bbn.com)
David Martin, SRI (martin_at_ai.sri.com) Sheila
McIlraith, Stanford KSL (sam_at_ksl.stanford.edu)
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Outline

• What is DAML?
• Observations
• Semantic Web Queries, Requests, Requirements
• The Big Picture (Web architecture and evolution)
• DAML-S DAML for Services
• Initially released May 30 2001

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DAML-S Working Group

• Joint work by
• SRI David Martin, Srini Narayanan, Jerry Hobbs
• Stanford Sheila McIlraith, Honglei Zeng
• CMU Katia Sycara, Terry Payne, Massimo Paolucci
• BBN Mark Burstein
• Nokia Ora Lassila

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What is DAML?

• An acronym DARPA Agent Markup Language
• A DARPA program
• An XML-based markup language
• An input to the W3C Semantic Web activity
• Will likely be proposed as the draft of a working
  group recommendation
• See also http//www.daml.org

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Characteristics of DAML

• Based on XML RDF(S)
• Beyond RDF properties of properties, equivalence
  and disjointness of classes, more constraints,
  etc. Feature comparison http//www.daml.org/lang
  uage/features.html
• Layered approach
• XML gt RDF(S) gt DAMLOIL gt (DAML-L) gt DAML-S
• Semantics for Web resources from Knowledge
  Representation concepts
• DAMLOIL can be regarded as a description logic
• Ontologies can be distributed, referenced by URI
• Logical rules can be described, applied using
  inference engines
• DAML-S A DAMLOIL ontology for (e.g. Web)
  Services

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Queries, Requests, Requirements

• Find a reference to the latest paper on SHOE
  with James Hendler as a co-author.
• All concepts identified unambiguously (by URIs)
• http//www.cs.umd.edu/projects/plus/DAML/onts/docm
  nt1.0.damlDocument
• Ontologies distributed across the web
• ltOntology about""gt
• ltversionInfogtdocument-ont, v.1.0lt/versionInfogt
• ltcommentgtAn ontology that models documents,
  particularly publicationslt/commentgt
• ltimports resource"http//www.cs.umd.edu/project
  s/plus/DAML/onts/base1.0.daml"/gt
• ltimports resource"http//www.cs.umd.edu/project
  s/plus/DAML/onts/general1.0.daml"/gt
• lt/Ontologygt
• Latest, etc. no closed-world assumption

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Using Distributed Theories
Scales Ontology/Theory
Processes Ontology/Theory
Geography Ontology/Theory
Preferences Ontology/Theory
Dates Times Ontology/Theory
Security Ontology/Theory
MapBlast
Travel Ontology/Theory
Personal Travel Agent SNARK
nau.edu/latlongdist
SRI Travel Ontology/Theory
Process Interpreter
Web Sites
Travelocity Travelocity DAML Annotations
My Travel Ontology/Theory
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Queries, Requests, Requirements

• Meta-data for a response is (very likely)
  distributed
• Find a reference to a paper having 2 authors,
  both of which have been PIs for a DARPA
  project.
• Combine information queries with service requests
• If Daniel Dennett has published a book about
  consciousness, request the Stanford Library to
  hold it for me.
• Compose services
• Get me a flight to Washington DC, and reserve a
  room near the airport
• Multiple participants in single transactions
• Airline, hotel, travel agent, meeting scheduler

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DAML-S Goals

• Develop upper ontology for describing, using
  services.
• Suport full automation of service use
• Provide enough information for an agent to find,
  select, and use a service never before
  encountered
• Enable Composition of Services
• Allow for composition of information gathering
  and transactional services
• Many components tools can work for both
• Search selection, ontology translation,
  transaction planning...
• Support inference in selecting and using services

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Upper Ontology for Services

• A foundation for creating many service ontologies
• But not a mandate for specific ontologies
• May provide deeper ontologies for Meta-services
• Can be specialized in many different ways
• No one official hierarchy of services
• But agents always know how to get started
• Top-level specs provide consistency
• Existing taxonomies can be mapped

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Service Ontology Top-level Classes
Service
Resource
provides
presents
supports
describedBy
ServiceProfile
ServiceGrounding
ServiceModel
How to communicate with it (e.g. Transport
Protocols)
What theservice does Advertisement
How to use it A Recipe
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Example Specialization for a B2C Site
B2C-Service
B2C-Lookup
B2C-Purchase
B2C-AccountMgmt
Congo-Lookup
Congo-Purchase
Congo-AccountMgmt
CP-Profile
CP-Grounding
CP-Model
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Service ProfileWhat does it do?

• Requirements, benefits, results of use
• Black box view used to advertise the service
• Information needed to find and select a service
• Inputs, outputs, preconditions, effects,
• Binding rules for inputs, outputs
• Roles involved
• May vary for different service classes
• Can employ logical rules
• (e.g. to describe applicability)
• Analogous to Yellow pages entry, w. specifics,
  constraints on use

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B2C Purchase Profile

• Intended Purpose The primary (intended)
  effectsOwn(Item)
• Input(s) ItemDescription (several forms),
  PriceRange, AcctName, Passwd, CreditCard,
  Shipping-address,
• Input usage rule
• Exists(Acct) gt Defined(CreditCard,
  Shipping-Address)
• Precondition
• Exists(Acct) CanCreate(Acct)
• Output Succeed Receipt Cancel Fail
• Effect Succeed ? ShippingOrderPlaced

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Service ModelHow does it work?

• Semantic description of a service
• Glass box view
• Detailed characterization of how to use it, what
  it does
• Decomposes process down to level of executable
  messages, transactions
• May vary for different service classes
• A process description
• may employ logical rules,
• Analogous to description of procedure body

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Process Model(SubClass of ServiceModel)

• Shared knowledge to coordinate services roles
• Draws on work in AI planning, workflow,
• Expresses state changes resulting from actions
• Describes sequences of possible interactions for
  an extended transaction
• Hierarchical process decomposition
• Executable semantics
• Can be used for task planning, scheduling,
  reachability analysis, etc.

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Process Ontology
ServiceModel
ProcessControl
subClassOf
ProcessModel
Input output participant precondition effect ...
expand/contract
Process
CompositeProcess
component
ProcessBag
ProcessList
If/Then/Else
Sequence
Split
RepeatUntil
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AI-inspired Action/Process Metaphor
Output

• confirmation no.
• ...

Input

• ticket purchased
• credit card debited
• ...

Effect

• customer name
• flight number
• credit card
• ...

www.acmeair.com BookFlight service
Y
flight available valid credit card
?
Preconditions
N

• knowledge of
• the input
• own credit card
• ...

• failure notification

Output
ltno effectgt
Effect
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B2C Purchase Expanded Process Model
Simple and Compositeservice descriptions
Locate-Goods
Put-in-Cart
Check-out
OR
Sign-in
Create-Account
Load-Prefs
Create-Prefs
Expands to
Purchase
Composite process
Select-Payment-Method
Simpleprocess
Specify-Delivery-Address
Giftwrap
Finalize
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Service GroundingHow is it used?

• Implementation-specific details for accessing the
  service
• Message formatting, transport mechanisms,
  protocols, serializations of all types
• Service Model Grounding give everything needed
  for using the service
• Examples HTTP forms, SOAP, KQML, CORBA IDL, OAA
  ICL, Java RMI

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B2C-Purchase Grounding

• Transport Secure HTTP
• Protocol HTTP Forms
• Address https//buybot.congo.com4040/initsub.htm
  
• Type Serializations
• ItemDescription (keywords) Set of DAML literals
• PriceRange pair of monetary units, ISO 5678
• CreditCard https//transcredit.com/S1.damlSecure
  TransferFormat

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Recap of Upper Ontology for Services

• Profile supports service selection
• Model Grounding support execution, monitoring,
  composition,
• Profile and Model are abstractGrounding makes
  it concrete
• There can be multiple of each
• One-to-one correspondence not required

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Comparison with Developing E-Commerce Standards

• DAML-S has been compared to
• UDDI
• WSDL
• E-speak
• ebXML
• see http//www.daml.org/services/daml-s/2001/05/su
  rvey-f-release.pdf
• DAML-S has more explicit semantics and is
  (because of DAML) can be more expressive than
  existing e-commerce standards, but
• Still early in development. Integration with
  these standards would be desirable, preferable.

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Summary

• The Semantic Web will be big
• It will support a wide variety of (mixed) queries
  and requests, in a semantically-grounded way
• KB representational techniques, ontologies,
  axioms, reasoning are likely to be important
  elements
• Services can be advertised, found, executed,
  monitored, and composed using DAML-S
• Search engines portals will evolve ontology
  translation services will become essential.
• Sharing ontologies for both services and content
  when possible will make everyones (integration)
  job easier.

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Status

• DAML-S v0.5 is now available for comment,
  feedback at http//www.daml.org/services/
• Joint work by SRI, Stanford KSL, CMU, BBN, Nokia
  supported by DARPA