1 interoperability in agentspace: proposal of agent interface to environment stanisław...
Post on 29-Dec-2015
214 Views
Preview:
TRANSCRIPT
1
Interoperability in Agentspace: proposal of agent interface to environment
Stanisław Ambroszkiewicz IPI PAN, Warsaw,
Poland
Supported by ESPRIT project CRIT2September 2000
2
FOCUS OF OUR RESARCH: Agent organizations in Cyberspace
Autonomous, heterogeneous agents are supposed to form organizations!
The key issues:•Infrastructure
• Interactions: mobility, communication, services, ...
•Semantic interoperability• Understanding: negotiation, cooperation, …
3
Interoperability
agent communities A1, A2, A3, … in a world (AGENTSPACE)
a community Ai consists of homogeneous agents perceiving the world, interacting and speaking their own language Li
interoperability between heterogeneous communities: heterogeneous agents can interact and understand each other
A3A1 A2
AGENTSPACE:
L1 L2
L3
4
Interoperability continued
Fix agent community A1 What does it mean: perceiving the world, interacting,
speaking language L1, and understanding each other ??? perfect (interaction and semantic) interoperability
inside A1:common interaction infrastructure is NOT necessaryexplicit meaning (ontology) of L1 is not needed !
A1
L1
5
Interoperability continued
interoperability between heterogeneous communities: heterogeneous agents can interact and understand each other interaction interoperability: common interaction
infrastructure; semantic interoperability, explicit semantics is
necessary: language for ontology interchange + interpretation
of O2 into O3 and vice versameaning of concepts is reduced to common generic
representation of the world structure
A2L2,O2
A3L3, O3
Common interaction infrastructure
OIL or generic representation of the world
6
Generic MAP architecture as Interaction Infrastructure
PEGAZ - our MAP for agents, services, and agent
organizations development
Java Virtual MachineJava Virtual Machine
Win 95/98
Internet/Intranet/WAN/LAN (TCP,UDP)
LINUX SunOS MS Win NT
Mobile Agent Platform - a uniform view of Cyberspace
place place placeservice
7
AGENT ARCHITECTURE
Environment:
Agent memory, i.e. local states
situations
Perception
Communic-ation
LearningRoutine execution
Decision mechanism
Goal
Library of routines
KNOW
agent or service
Action: communicate
communicate
event
Interface
8
Proposal of agent interface to environment
Responsible for interactions. Based on MASIF / FIPA standard. It assures interaction interoperability: migration, communication, using services, etc.
The goal: means to achieve semantic interoperability
Representation layer
Agent interface:
Communication Language
Functionality layer
Language layer
Representation of the world (Agentspace) structure. Local event structure is the basis for the representation. Agents perceive the environment in the same way
Communication Language: simple query language for homogenous agents and Meaning Interchange Language (MIL to be constructed) for heterogeneous agents
9
The idea behind
The reason for common interface: nothing in common = no understanding, i.e. no semantic interoperability
Functionality layer: MASIF / FIPA standard are not sufficient; still work in progress
Our proposal: Representation layer as formal representation of the
structure determined by the functionality level : generic MAP environment & mechanisms for acquiring knowledge from perception (already done!)
Language layer - MIL (Meaning Interchange Language) - work in progress
10
ENVIRONMENT of a Mobile Agent Platform
place place placeservice
11
FORMAL SPECIFICATION OF GENERIC MAP ENVIRONMENT
Primitive entities:
places, agents, services, resources
Primitive actions: migrate, use service, take (give) resource, communicate with agent (service)
Events: each event represents an action execution - local interaction of agents, services and places involved in the execution
communicate
place placemigrate
take / give
use service
12
FORMAL SPECIFICATION OF GENERIC MAP ENVIRONMENT
Partial order of events
service......
service
13
AGENT MEMORY
Agent’s memory: collection of variables V1 , V2, … , Vk (abstraction of database) standing for concepts.
concept vi = ( name , carrier , meaning )
variable vi = (identifier, type, modification way)
14
ACQUIRING KNOWLEDGE 1: FROM PERCEPTION
place placemove
where the current location is stored
where names of services are stored
where the info on contents is saved
Update variable: at event:
15
ACQUIRING KNOWLEDGE 2: FROM COMMUNICATION
Query
Answer
Query: what is your Vi ? Answer: my Vi=10. Agent: revision of Vi; preserve Vi, change Vi to 10 or compute new value
Vi is used in the same way by the homogeneous agents !!!
Homogeneous agents:
Agents’ databases are of the same type, i.e., V1 , V2, … , Vk (of blue agent) and V1,V2, ... ,Vk (of green agent) , and Vi and Vi are of the same type for i=1,2,...,k
16
CONCEPT MEANING is the way the
concept is used (Wittgenstein)
meaning of Vi = the way Vi is used in updating and revision updating and revision mechanisms are the same for all homogeneous agents !!! The same interfaces !!!
Vi
update
agent
revise
Agent’s database
Agent’s interface:
Funct
ionalit
y layer
Repre
senta
tion layer
Language layer
Vi
a homogeneous agent
Environment:Perceptio
nevent
sambrosz:
meaning of concept is defined inside a community of homogeneous agents; sharing the same ontology
sambrosz:
meaning of concept is defined inside a community of homogeneous agents; sharing the same ontology
Communication
17
Meaning Interchange Language: MIL
Ontology of society A1
Concepts: v1; vi
Functionality layer
Representation layer
Language layerReduction of concept meaning Concept formation
from / to a heterogeneous agent
generic meaning of v1 (in RDFS ?)
generic meaning of vi (in RDFS ?)
? ?
18
Conclusion
What has been done: Specification of the representation layer;
What not: The rest of the interface;
Future work: Construction of MIL, generic rules
(primitive constructors) for concept formation;
23
SEMANTIC INTEROPERABILITY:agents can identify, communicate and understand each other
to understand each other they must agree on the meaning of concepts they use!
KEY ISSUE: meaning, semantics (ontology) represented in a machine-readable way
Natural language: Can we represent the meaning of concepts (we use) explicitly, i.e. in a machine-readable way? A fundamental problem !!!
Kant , Husserl, Wittgenstein, …
24
Formal approaches to semantics and semantic interoperability
Tarskian semantics: semantics of a theory is given by interpretation in a model. The model is another theory !!!
Ontolingua: Gruber, Guarino et al.: meaning of concept is constrained by logical axioms.
OKBC - Open Knowledge Base Connectivity, exchange standard for ontologies chosen by FIPA
XML and RDF web standards for information exchange
OIL - Ontology Interchange Language, a European project
DAML project - DARPA Agent Markup Language: a semantic language that ties the information on page to machine-readable semantics
top related