DAMLS: Bringing Semantics to Web Services

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DAML-SBringing Semantics toWeb Services

• David Martin
• SRI International
• http//www.daml.org/services/

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DAML-S Web Services Coalition

• CMU Massimo Paolucci, Terry Payne, Katia Sycara,
  Norm Sadeh
  
• BBN Mark Burstein
• Nokia Ora Lassila
• Stanford KSL Sheila McIlraith, (Honglei Zeng)
• SRI Jerry Hobbs, David Martin, (Srini
  Narayanan)
  
• Yale Drew McDermott

Founded February, 2001
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What is DAML-S?

• DARPA Agent Markup Language for Services
• A DAMLOIL ontology/language for (formally)
  describing properties and capabilities of Web
  services
  
• An approach that draws on many sources
• Description logic
• AI planning
• Workflow
• Formal process modeling
• Agents
• Web services
• http//www.daml.org/services/

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Layered Approach to Language Development
A major application of DAMLOIL
Future versions will build upon emerging layers
(e.g. DAML-Rules)

DAML-S (Services)
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DAML-S Objectives

• Automation of service use by software agents
• Ideal discovery, selection use of services
  never before encountered
  
• Useful in the real world
• Incremental exploitation
• Enable reasoning/planning about services
• e.g., On-the-fly composition
• Integrated use with information resources
• Ease of use powerful tools

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Automation Enabled by DAML-S

• Web service discovery
• Find me a shipping service that transports goods
  to Dubai.
  
• Web service invocation
• Buy me 500 lbs. powdered milk from
  www.acmemoo.com
  
• Web service selection composition
• Arrange food for 500 people for 2 weeks in
  Dubai.
  
• Web service execution monitoring
• Has the powdered milk been ordered and paid for
  yet?
  

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Upper Ontology of Services
Ontology images compliments of Terry Payne, CMU
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Service Profile What does it do?

• High-level characterization/summary of a service
• Provider participants
• Capabilities
• Functional attributes (e.g., QoS, region served)
• Used for
• Populating service registries
• A service can have many profiles
• Automated service discovery
• Service selection (matchmaking)
• One can derive
• Service advertisements
• Service requests

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Service Profile
Capability Description
Provenance Description
Functional Attributes
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Service Profile Provenance Description

• Service overview participants
• serviceName textDescription
• intendedPurpose roles of Actors
• Details about
• Providers
• Requesters
• 3rd PartyActors

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Service Profile Capability Description

• Specification of what the service provides
• High-level functional representation in terms
  of
  
• preconditions
• inputs
• (conditional) outputs
• (conditional) effects

• Summarizes the top-level Process (described by
  Service Model)

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Service Profile Functional Attributes

• Provide supporting information about the service,
  including

• geographical scope
• Pizza Delivery only within the Pittsburgh area
• quality descriptions and guarantees
• Stock quotes delivered within 10 secs
• service types, service categories
• Commercial / Problem Solving etc
• service parameters
• Average Response time is currently ...

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Service Profile Styles of use

• Class-hierarchical yellow pages
• Implicit capability characterization
• Arrangement of attributes on class hierarchy
• Can use multiple inheritance
• Plan summaries
• More explicit
• Preconditions, effects
• Less reliance on formal hierarchical
  organization
  
• Summarizes process model specs

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Exploiting Taxonomies of Services
nameproviderroleavgResponseTime?
ServiceProfile
FeeBased
feeBasispaymentMethod
ProductProvidingService
ActionService
Physical_Product
Manufacturing
InfoService
InformationProduct
physicalProductmanufacturerdeliveryRegiondel
iveryProviderdeliveryType
PhysicalProductService
Repair
physicalProduct
Tie in with UDDI, UNSPSC, DL Basis for
matchmakingMultiple profiles multiple taxonomies
transportationModegeographicRegion
Transportation
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Upper Ontology of Services
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Service ModelHow does it work?
Process Model How does it work?

• Each service is conceived as atomic or composite
  process
  
• Simple (abstract) processes can specify views
  of atomics composites
  
• Allows for black box and glass box views of
  composite services
  
• Associated with each process is a set of inputs,
  outputs, preconditions and effects
  
• Composite processes are composed of other
  processes using constructs such as sequence,
  if-then-else, fork,...
  
• Process model (and process execution model) used
  for
  
• (automated) Web service invocation, composition,
  interoperation, monitoring

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Service Model / Process Model
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Function/Dataflow Metaphor
Input
Output

• customer name
• origin
• destination
• weight
• pickup date
• ...

• confirmation no.
• ...

Acme Book Truck Shipment
Y
truck available valid credit card
?
N

• failure notification

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AI-inspired Action/Process Metaphor
Output

• confirmation no.
• ...

Input

• customer name
• origin
• destination
• pickup date
• ...

• goods at location
• if successful
• credit card debited...

Effect
Y
truck available valid credit card
?
Preconditions
N

• knowledge of
• the input
• ...

• failure notification

Output

Effect
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Composite Process
Output Effects
Input Preconditions
AcmeTruckShpng

• confirmation no.
• ...

• customer name
• location
• car type
• dates
• credit card no.
• ...

www.acmecar.com book car service
?

• failure notification

?

• confirmation no.
• ...

• confirmation no.
• dates
• room type
• credit card no.
• ...

• confirmation no.
• ...

www.acmehotel.com book hotel service
?

• customer name
• flight numbers
• dates
• credit card no.
• ...

www.acmeair.com book flight service
?

• failure notification

• failure notification
• errror information

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Simple and Composite Processes
AcmeTruckShpng
ExpandedAcmeTruckShpng
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Upper Ontology of Services
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Service Grounding How to access it

• Implementation-specific
• Message formatting, transport mechanisms,
  protocols, serializations of 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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DAML-S / WSDL Grounding

• Web Services Description Language
• Authored by IBM, Ariba, Microsoft
• Focus of W3C Web Services Description WG
• Commercial momentum
• Specifies message syntax accepted/generated by
  communication ports
  
• Bindings to popular message/transport standards
  (SOAP, HTTP, MIME)
  
• Abstract types extensibility elements
• Complementary with DAML-S

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DAML-S
DL-based Types
Process Model
Inputs / Outputs
Atomic Process
Message
Operation
Binding to SOAP, HTTP, etc.
WSDL
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DAML-S / WSDL Grounding (contd)
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DAML-S / WSDL Grounding (contd)
WSDLDocument


daml-property
inputX
daml-property
outputY
daml-s-process
AtomicProcess
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Review Upper Ontology of Services
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Language Evolution to Date

• Release 0.5 (May 2001)
• Initial Profile Process ontologies
• Release 0.6 (December 2001)
• Refinements to Profile Process
• Resources ontology
• Two approaches to formal semantics
• Sycara/Ankolekar, McIlraith/Narayanan
• Release 0.7 (coming soon)
• DAML-S/WSDL Grounding
• More complete examples
• Release 1.0 (later this year)
• Process model issues

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Related Activities

• Web site mailing lists
• http//www.daml.org/services/
• www-ws_at_w3.org
• Use cases
• DAML-S Publications
• WWW10 Sem. Web. Workshop (2), SWWS, WWW11,
  Coordination 2002, AAMAS (poster), ICSW (4),
  
• Monitoring W3C Web services activities
• Designated liaison for Web Services Arch. WG

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Tools and Applications
DAML-S is just another DAMLOIL ontology
? All the tools technologies for DAMLOIL are
relevant Some DAML-S Specific Tools and Technol
ogies Discovery, Matchmaking, Agent Brokering
CMU, SRI (OAA), Stanford KSL Automated Web Ser
vice Composition Stanford KSL, BBN/Yale/Kestrel,
CMU, MIT, Nokia, SRI DAML-S Ed
itor Stanford KSL, SRI, CMU (profiles),
Manchester Process Modeling Tools Reasoning
SRI, Stanford KSL Service Enactment /Simulation
SRI, Stanford KSL Formal Specification of
DAML-S Operational/Execution Semantics
CMU, Stanford KSL, SRI
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Challenges

• Finding the 80/20 line
• Where and how to go beyond DAMLOIL?
• Interface between DL ontology, logical
  expressions, algorithm/workflow representation
  
• Profiles more explicit
• Process modeling many issues
• Variability of public/private aspects of
  Processes
  
• Extending to offline (sub)processes
• Generalizing to multiple roles
• Failure, transactions
• Connecting with Industry
• Showing compelling value
• Not promising too much
• Providing an incremental path

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(Some) Related Work

• Related Industrial Initiatives
• UDDI ebXML
• WSDL .Net
• XLANG Biztalk, e-speak, etc
• These XML-based initiatives are largely
  complementary to DAML-S.
  
• DAML-S aims to build on top of these efforts
  enabling increased expressiveness, semantics, and
  inference enabling automation.
  
• Related Academic Efforts
• Process Algebras (e.g., Pi Calculus)
• Process Specification Language (Hoare Logic,
  PSL)
  
• Planning Domain Definition Language (PDDL)
• Business Process Modeling (e.g., BMPL)
• OntoWeb Process Modeling Effort

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Summary

• The service paradigm will be a crucial part of
  the Semantic Web
  
• DAML-S supports service descriptions that are
  integral with other Semantic Web meta-data
  
• DAML-S aims to enable automatic discovery,
  selection, invocation, composition, monitoring of
  services
  
• Initial versions of Profile, Process, and
  Grounding ontologies are available
  
• Many challenges remain
• Were interested in synergy with related work
• http//www.daml.org/services/