Specification of Agent Services for DAML

Specification of Agent Services for

DAML

Katia P. SycaraKatia P. SycaraTerry R. PayneTerry R. Payne

Massimo PaolucciMassimo PaolucciDAML PI - July 01DAML PI - July 01

Carnegie Mellon Universityhttp://www.daml.ri.cmu.edu/

Carnegie Mellon Universityhttp://www.daml.ri.cmu.edu/

Current Aims / Goals

Develop language specifications, tools & applications that support creation and interoperation of services/agents.Need methodologies for Semantic service matching Peer-2-Peer and Middle-Agent mediated

semantic interoperation Agent-based planning/scheduling/execution

for service composition/decomposition

What’s Hot?DAML-S (with Services Coalition)

DAML-S Profile semantically presents the capabilities that the service provides.

DAML-S Process describe composition of the service. Provides framework for conversational policies and agent dialogs.

DAML-S Grounding… coming soon

Process & Profile Models (inc. Alpha-Air, Moving-House/Public Utilities scenario)

Retsina DAML-S Matchmaker & A-Match Service requests matched with advertised profiles Subsumption inference engine used to match functional

parameters

Task Modeler GUI Graphical editor that assists creation of high-level service

composition based on advertised services

What’s Hard?Providing concise but valid abstraction of the service process within the Profile

Tradeoff between expressivity and performance

Specialized reasoning for spatial & temporal concepts e.g. Physical locations vs proximal relationships

Efficient inferencing for the DAML-S matchmaker Will the matching and inferencing engines scale?

Constraining inferencing and reasoning across multiple ontologies?

Multiple advertisements may include many ontologies – reasoning space may be huge

PresentingService Profiles

Service Profile Presented by a service. Represents

“what the service provides”

One can derive: Service Advertisements Service Requests

DAML-S:

DAML-S Profile Ontology (Overview)

ProvenancProvenance e DescriptioDescriptionn

Functional Functional AttributesAttributes

Functionality Functionality DescriptionDescription

DAML-S Profile OntologyProvenance Description

Information and Provenance about the Service serviceName & textDescription intendedPurpose & role of 3rd Party Actors

Details about 3rd Party Actors Requesters Providers

DAML-S Profile OntologyFunctionality Description

Specification of what the service provides High-level functional representation in terms

of:

preconditions accessConditions inputs

outputs conditionalOutputs effects

Play a pivotal role for functionalservice matching within the Matchmaker

DAML-S Profile OntologyFunctional Attributes

geographical scopePizza 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 parametersAverage Response time is currently ...

Provide supporting information about the service, including:

DAML-S Profile OntologyAdvertisement (parameters)

<rdf:Property rdf:ID="location">

<rdfs:subPropertyOf rdf:resource="http://www.daml.org/…/Profile#input"/>

<rdfs:domain rdf:resource="#PAGas_Agent_Advertisement"/>

<rdfs:range rdf:resource="http://www.daml.ri.cmu.edu/…daml#Location"/>

</rdf:Property>

<rdf:Property rdf:ID="pricePerUnit">

<rdfs:subPropertyOf rdf:resource="http://www.daml.org/…/Profile#output"/>

<rdfs:domain rdf:resource="#PAGas_Agent_Advertisement"/>

<rdfs:range rdf:resource="http://www.daml.ri.cmu.edu/...daml#UnitCost"/>

</rdf:Property>

<rdf:Property rdf:ID="providesGas">

<rdfs:subPropertyOf rdf:resource="http://www.daml.org/…/Profile#effect"/>

<rdfs:domain rdf:resource="#PAGas_Agent_Advertisement"/>

<rdfs:range rdf:resource="http://www.daml.ri.cmu.edu/...daml#Gas"/>

</rdf:Property>

<rdf:Property rdf:ID="contract"> <rdfs:subPropertyOf rdf:resource=

"http://www.daml.org/services/…/Profile#output"/><rdfs:domain rdf:resource="#PAGas_Agent_Advertisement"/><rdfs:range rdf:resource=

"http://www.daml.ri.cmu.edu/ont/Realtor.daml#Contract"/></rdf:Property>

<rdf:Property rdf:ID="contract"> <rdfs:subPropertyOf rdf:resource=

"http://www.daml.org/services/…/Profile#output"/><rdfs:domain rdf:resource="#PAGas_Agent_Advertisement"/><rdfs:range rdf:resource=

"http://www.daml.ri.cmu.edu/ont/Realtor.daml#Contract"/></rdf:Property>

DAML-S Profile OntologyChallenges

Abstraction between functional description parameters

Differentiating preconditions/accessConditions Representing and matching effects & conditionalOutputs

Abstraction of functional attributes How to match high level concept classes? Need to provide framework for properties such as

geographicalRadius, serviceParameters & qualityGarantees How does one model “CloseTo” in daml+oil ???

Representing Composite Services within Profiles What is the degree of fidelity? Should Process and Profile parameters be equivalent? Or should the Profile represent an approximation of the

Process?

DAML-S ProfileService Matchmaking

Working prototype of a Retsina middle-agent: DAML-S Matchmaker Matches DAML-S requests with advertised

DAML-S profiles Uses simple subsumption-based inference

engine Returns correspondence table to match the

request and advertisement interfaces

DAML-S ProfileService Matchmaking (cont)

Retsina Middle Agents maintain abstraction between Protocol (eg broker vs yellow-pages) Matching Engine Inference Engine Housefinder.coHousefinder.co

mmcmu.educmu.edu

StudentAID.orStudentAID.orgg

umbc.eduumbc.edu

Service Service RequestorRequestor

Service Service ProvidersProviders

yale.eduyale.edu

Inferencing Engine

Matching Engine

Pro

toco

l

MatchmakerMatchmaker

DAML-S ProfileSubsumption Matching

Service Requestors have knowledge about their request, but no knowledge of the available service providers.Current matching engine assumes:

Requests should be more general than advertisements w.r.t inputs

Requested outputs should be more specific than the advertised outputs

Current inference engine reasons about taxonomic hierarchies and equivalence relationshipsHowever, alternative engines that utilize the full power of DAML should be investigated…

DAML-S ProfileMatchmaker Challenges

Abstraction between matching engine and inference engine

What type of inferencing is required? Different inferencing policies for different Profile

properties Some inferencing policies may result in bad or

infeasible matches Implications on complexity, performance, scalability

Rapid reasoning for many advertisements? How does logical reasoning in DAML effect matching? Use sequential, filtered or other matching policies? How to match functional relationships between

parameters? E.g. matching/translating Length & Width vs Area Search through space of interface maps…

DAML-S ProfileA-Match: accessing the Matchmaker

Web based user interface to the Retsina DAML-S MatchmakerHumans can: Register

advertisements Browse advertised

profiles Issue requests View matching

advertisements

DAML-S ProfileModeling Composite Tasks

DAML-S Task Modeler Graphical tool for defining and composing

complex tasks.1. Create tasks at an

abstract level, and link together to define workflow

2. Define task definition for each abstract task

3. Search for specific services/agents and instantiate tasks

DAML-S ProfileOther Ontologies…

DAML Service Ontologies DAML-S Service Ontologies (index) Task Modeler Ontologies (index)

Miscelaneous ATLAS DAML Ontologies AirportCodes (hyperdaml) - an older airport ontology. Airport (hyperdaml) - a newer airport ontology. City (hyperdaml) - top level City ontology. USCity (hyperdaml) - US Cities. State (hyperdaml) - top level State/County/Territory ontology. USRegionState (hyperdaml) - US States with Region Ontology CanadianState (hyperdaml) - Canadian Provinces and

Territories Country (hyperdaml) – with links to Stanford's DAML'd CIA

World Fact Book

http://www.daml.ri.cmu.edu/site/http://www.daml.ri.cmu.edu/site/ontologies.htmlontologies.html

Also available in the DAML Ontology Library (or coming soon)