1. The LARKS Project Katia Sycara, Matthias Klusch, Jianguo Lu,
Interoperability among Heterogeneous Agents in the Internet
Katia Sycara, Matthias Klusch, Jianguo Lu,
Zhendong Niu, Seth Widoff

2. Language for Advertisement and Requests for Knowledge Sharing
What is LARKS about?
Frame-based specification of ads and requests of agent capabilities.
Optional use of a domain ontology.
Automated processing of LARKS specifications.
Compatibility with XML.
Matchmaking Services via Matchmaker Agents using LARKS
to ‘match’ requests with relevant provider agents
in heterogeneous and dynamic agent societies.

3. Matchmaking Using LARKS
Matchmaker Agent x
AdvertisementDB
OntologyDB
AuxiliaryDB
Matching
Result-of-Matching
Capability Descriptions
in LARKS
Requester Agent
Provider Agent 1
Service Request
in LARKS
LARKS Protocol
for providing the
service
Provider Agent n
Local
Ontology 1 ? IS IS
Process Request
on Local IS IS
Local Ontology n

4. Specification in LARKS
Context
Context of Specification
Type
Data Types Used in Variable Declarations
Input
Input/Output Variable Declarations
Output
InConstraints
OutConstraints
Logical Constraints on Variables
(Pre-/Post-Conditions)
ConcDescriptions
Ontological Description of Used Words
TextDescription
Textual Description of Specification
Constraints: set of definite program clauses/goals (Horn clauses)
Concepts: ontological description of words in concept language ITL

5. Example for Ontology
(1) An Ontology written in the Concept Language ITL (Terminology):
AirMission  (and Mission (atleast 1 had-airplane) (all has-airplane Airplane)
(all has-MissionType aset(AWAC,BARCAP,CAP,DCA,HVAA))… )
AWAC-AirMission  (and AirMission (atleast 1 has-airplane) (atmost 1 has-airplane)
(all has-airplane aset(E-2)) …)
DCA-AirMission  (and AirMission (all has-MissionType aset(DCA))
(all has-F14 plane-F14D) (all has-F18 plane-F18)
(atleast 2 has-F14) (atmost 2 has-F14) (atleast 2 has-F18)
(atmost 2 has-F18) (atleast 2 has-E2) (atmost 2 has-E2) …)
. . .
(2) Concept Subsumption Hierarchy:
AirMission
. . .
AWAC-AirMission DCA-AirMission
HVAA-AirMission

6. Examples for Specification in LARKS
Agent Advertisement:
“I can provide information about air combat missions in general.”
AirCombatMissions
Context
Attack, Air, Combat, Mission*AirMission
Types
Date = (mm: Int, dd: Int, yy: Int);
Input
Output
missionTypes: SetOf(String);
missionAirplanes: SetOf(String);
missions: ListOf(mType: String, mID:String|Int,
mStart: Date, mEnd: Date);
InConstraints
OutConstraints
mStart <= mEnd
ConcDescriptions
[AirMission]
TextDescription
information about air combat missions in general

7. Combat, Mission*AWAC-AirMission
Agent Advertisement:
“I can provide information about deployed and launched AWAC air combat missions. ”
AWAC-CombatMissions
Context
Combat, Mission*AWAC-AirMission
Types
Date = (mm: Int, dd: Int, yy: Int);
DeployedMission =
ListOf(mType: String, mID:String|Int,
mStart: Date, mEnd: Date);
Input
Output
missions: DeployedMission;
InConstraints
OutConstraints
deployed(mID), mType = AWAC,
launched_after(mID,mStart), launched_before(mID,mEnd).
ConcDescriptions
[AWAC-AirMission]
TextDescription
information about deployed and launched AWAC air
combat missions

8. Combat, Mission*DCA-AirMission
Agent Advertisement:
“I can provide information about deployed and launched DCA air combat missions.”
DCA-CombatMissions
Context
Combat, Mission*DCA-AirMission
Types
Date = (mm: Int, dd: Int, yy: Int);
DeployedMission =
ListOf(mType: String, mID:String|Int,
mStart: Date, mEnd: Date);
Input
Output
missions: DeployedMission;
InConstraints
deployed(mID), mType = DCA,
launched_after(mID,mStart), launched_before(mID,mEnd).
OutConstraints
ConcDescriptions
[DCA-AirMission]
TextDescription
information about deployed and launched DCA air
combat missions

9. “Find an agent who can provide information on
Request:
“Find an agent who can provide information on
deployed air combat missions launched in a given time interval.”
Req-AirCombatMissions
Context
Attack, Mission*AirMission
Types
Date = (mm: Int, dd: Int, yy: Int);
Mission = ListOf(mType: String, mID:String|Int,
mStart: Date, mEnd: Date);
Input
sd: Date, ed: Date;
Output
missions: Mission;
InConstraints
sd <= ed.
OutConstraints
deployed(mID), launched_after(mID,sd),
launched_before(mID,ed), sd >= mStart, ed <= mEnd.
ConcDescriptions
[AirMission]
TextDescription
information on deployed air combat missions launched
in a given time interval

10. “Find an agent who can provide information on
Request:
“Find an agent who can provide information on
deployed and launched air combat missions that contain F-14 airplanes.”
Req-DeployedF14CombatMissions
Context
Combat, Mission*F14-Mission
Types
Date = (mm: Int, dd: Int, yy: Int);
Mission = ListOf(mType: String, mID:String|Int,
mStart: Date, mEnd: Date);
Input
Output
missions: Mission;
InConstraints
OutConstraints
deployed(mID), launched_after(mID,mStart),
launched_before(mID,mEnd).
ConcDescriptions
F14-Mission  (and AirMission (atleast 1 has-F14))
TextDescription
information on deployed and launched air combat missions
that contain F-14 airplanes

11. An Example of Matchmaking Using LARKS
“Find agents that
can inform about
air combat missions”
Requester Agent
Ranked Set of Agents
capable to inform about
air combat missions
AirCombatMissions
Matchmaker Agent
AuxiliaryDB
OntologyDB
AdvertisementDB
AWAC-AirCombatMissions
Context
Matching
Profile
Matching
Similarity
Matching
Signature
Matching
Semantical
Matching

12. Matchmaking Process Main Steps: Context Matching Word Distances
(pairwise matching of specifications in LARKS)
Context Matching
Word Distances
Subsumption or Equality of attached Concepts
Syntactical Matching
Comparison of Profiles (TF-IDF)
Similarity Matching of Declarations and Constraints
Word Distances
Distances in the Ontology (Weighted Associative Network)
Full Signature Matching of Declarations
Subsumption of Data Types
Semantical Matching
Logical Implication of Constraints

13. Different Matching Modes
 “Complete Matching”:
All filters.
 “Relaxed Matching”:
No signature matching.
 “Profile Matching” :
Comparison of profiles (TF-IDF) only.
 “Plug-In Matching”:
Signature and semantical matching only.
Any combination of filters may be chosen by the user.

14. Matchmaking Process: Simple Example
 Request for Agent Capability in ‘Req-AirCombatMissions’
Advertisement of Agent Capability in ‘AWAC-AirCombatMissions’
Mode  Complete Matching
Context Matching 
Look-up/compute word distances for (Attack, Combat), (mission, Mission);
All value exceeds given threshold.
Attached concepts (AirMission,AirMission) are terminologically equal.
Syntactical Matching
Comparison of Profiles (TF-IDF) 
Profile similarity value of documents exceeds given threshold.
Thus, proceed with

15. Matchmaking Process: Simple Example (cont’d)
Syntactical Matching (ff.)
Full Signature Matching of Declarations 
Input declarations -
A: D21 = sd: Date, ed: Date;
Output declarations -
R: D12 = missions: ListOf(mType: String, mID:String|Int,
mStart: Date, mEnd: Date);
A: D22 = missions: ListOf(mType: String, mID:String|Int,
A: D23 = missionTypes: ListOf(String);
A: D24 = missionAirplanes: ListOf(String);
Apply Type Inference Rules for Computing Type Subsumption.
Result:
(TRUE) & (signature(A: D22) › signature(R: D12))
Thus, proceed with

16. Matchmaking Process: Simple Example (cont’d)
Similarity Matching 
Conceptual Attachment to words
Check word distances in declarations and constraints
Similarity value of two specifications:
Average of sum of similarity computations
among all pairs of declarations and constraints.
Similarity of AirCombatMissions
and Req-AirCombatMissions = 0.75
(Note: Value strongly depends on the used word distance database)
Similarity value exceeds given threshold.
Thus, proceed with

17. Matchmaking Process: Simple Example (cont’d)
Constraint Matching fails
InConstraints  InConstraints
in Req-AirCombatMissions in AirCombatMissions 
sd <= ed.
OutConstraints  OutConstraints NOT 
in AirCombatMissions in Req-AirCombatMissions
mStart <= mEnd deployed(mID), launched_after(mID,sd),
launched_before(mID,ed), sd >= mStart, ed <= mEnd.

18. Matchmaking Process: Simple Example (2)
 Request = Req-DeployedF14CombatMissions, Ad = DCA-CombatMissions
Context Matching  (Ad:) DCA-AirMission < (Req:) F14-Mission
Syntactical Matching
Comparison of Profiles (TF-IDF) 
Full Signature Matching of Declarations 
Similarity Matching  Sim(Req,Ad) = 0.62
Constraint Matching
InConstraints in Req  InConstraints in Ad 
OutConstraints in Ad  OutConstraints in Req 
deployed(mID), mType=DCA,
launched_after(mID,sd),
launched_before(mID,ed),
deployed(mID),
launched_after(mID,sd),
launched_before(mID,ed),

19. Current Implementations of LARKS Project
Web-based Interface for Specification of Requests in LARKS
Matchmaker module
Knowledge management module (Concept classifier, KB)

20. Graphical User Interface to the Matchmaker

21. TSC:
Concept Classifier
for Knowledge Base

22. Matchmaking Using LARKS and XML
Translation of LARKS specification into XML document
Automated Processing of LARKS/XML Specs
Translation of ITL concept definitions into XML statements
e.g. use of XML-Data Schemas, W3C Note 05 Jan 1998
Proposal by Microsoft;
Translated ITL ontologies in XML used as XML-namespaces

23. Some Future Work of the LARKS Project
Complete Implementation in Java
Multi-Agent Test Environment Using RETSINA Communicator
Natural Language Interface for Human-Agent Interaction
Extensive Real-World Testing