Post on 27-Mar-2015
SWSA discovery
Overview
• Models of discovery– Broker Matchmaker P2P
• Structure of discovery– Discovery– Selection
• Role of semantics
Discovery ProcessGoal
Abstraction to capabilities
Capability Description
Match
Advertisement
List of Providers
Selection
Potential Providers
Enactment
Store
Request
• MatchmakingMatchmaking– (UDDI)(UDDI)
• BrokerBroker
• P2PP2P
Three Models of DiscoveryThree Models of Discovery
Matchmaker
Goal
Abstraction to capabilities
Capability Description
Match
Advertisement
List of Providers
Selection
Potential Providers
Enactment
Store
Request
MatchmakingMatchmaker
Report Info
Goal
Abstraction to capabilities
Capability Description
Match
Advertisement
List of Providers
Selection
Potential Providers
Enactment
Store
Brokering
Goal
Abstraction to capabilities
Capability Description
Match
Advertisement
List of Providers
Selection
Potential Providers
Enactment
Store
Request
P2P (1)
Report Info
Goal
Abstraction to capabilities
Capability Description
Match
Advertisement
List of Providers
Selection
Potential Providers
Enactment
Store
P2P (2)
Report Info
Katia 9
Provider Ad
Requester Pref Provider Only
Provider + Middle Agent
Provider+
Middle Agent +
Requester
Requester Only None “front Agent”
Matchmaker
P2P –1
UPNP
Requester + Middle Agent
Anonymizer
Broker
BrokerCMU Broker
WSMO Mediators?
Recommender
MatchmakerUDDI
Requester+
Middle Agent +
Provider
Black Board
P2P Gnutella JXTA
Introducer/
Bodyguard
Matchamker –1
Arbitrator
“Pure” P2P
Katia’s 28 Dimensions of discovery1. Direction: push vs pull
• In UDDI provider pushes, requester pulls• In P2P provider pulls, requester pushes
2. Amount Info in adv: capabilities vs parameters• Is there any discovery service that makes this difference?
3. Action for advertisement: broadcasting vs retaining• P2P does broadcasting • UDDI does retaining
4. Browsing MA DB? Yes vs no• UDDI supports persistent queries
5. Amount Info in request: capability only vs parameters• Is there any discovery service that makes this difference?
6. Does MA mediate transaction?• Broker vs registry
• Since some of the combinations are irrelevant there are 28 possible MA
Importance of Semantics
Goal
Abstraction to capabilities
Capability Description
Match
Advertisement
List of Providers
Selection
Potential Providers
Enactment
Store
Request
The transformation should preserve the semantics of the query: it should not identify capabilities do not lead to the satisfaction of the goal
Ask Mike Huhns
Matching requires the recognition of whether the required capabilities are “similar enough” to the requested capabilities, ie the services that they describe (their meaning) provide similar functionalities
Selection requires matching of own requirements visa vie the requirements of the providers and the functionality that they provide. The services selected are the one that provide the closest match.