Multiagent System Communication
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Transcript of Multiagent System Communication
Introduction
An agent is a computer system capable of autonomous action in some
environment in order to meet its design objectives
Agent communication is essential for facilitating cooperation,
coordination, negotiation, and other aspects of agent interaction
Agent Communication Languages (ACLs)
Agents Communication Language (ACL) provides agents with a means
of exchanging information and knowledge.
Number of languages have been developed specifically for agent
communication.
Knowledge Sharing Effort (KSE)
In the early 1990s, Knowledge Sharing Effort (KSE) was formed &
sponsored by the Advanced Research Projects Agency (ARPA)
The Knowledge-Sharing Effort (KSE) is an initiative to develop the
technical infrastructure to support the sharing of knowledge among
autonomous information systems
The goal of this effort is to develop a technology that will enable
researchers to develop new systems
Participation by dozens of researchers in academia and industry
Knowledge Sharing Effort (KSE)
The KSE generated two main deliverables as follows:
i. The Knowledge Query and Manipulation Language (KQML)
ii. The Knowledge Interchange Format (KIF)
Knowledge Interchange Format (KIF)
KIF is a computer-oriented language for the interchange of knowledge
This language was originally developed with the intent of being a
common language for expressing properties & representing knowledge
of a particular domain
It was not intended to be a language in which messages themselves
would be expressed
KIF is a Langauge for expressing message content
Knowledge Interchange Format (KIF)
KIF is used to state:
i. Properties of things in a Domain (e.g. ‘John is a Chairman‘)
ii. Relationships between things in a Domain (e.g. 'Michael is Janine’s
Boss')
iii. General properties of a Domain (e.g. 'everybody has a mother')
Knowledge Interchange Format (KIF)
“The temperature of m1 is 83 Celsius”:
(= (temperature m1) (scalar 83 Celsius))
“An object is a bachelor if the object is a man and is not married”:(defrelation bachelor (?x) :=
(and (man ?x) (not (married ?x))))
“Any individual with the property of being a person also has the property
of being a mammal”:(defrelation person (?x) :=> (mammal ?x))
Knowledge Query and Manipulation Language (KQML)
KQML is a message-based language for agent communication. Thus
KQML defines a common format for messages
It was developed by the ARPA-supported Knowledge Sharing Effort and
independently implemented by several research groups
KQML is a language that is designed to support interaction among
intelligent software agents
The KQML language simplifies its implementation by allowing KQML
messages to carry useful information:
Such as the names and addresses of the sending and receiving agents,
a unique message identifier, and notations by agents
Knowledge Query and Manipulation Language (KQML)
KQML is a language that defines various acceptable ‘communicative
verbs’, or Performatives (such as: ask, reply)
Example Performatives:
• ask-if (‘is it true that. . . ’)
• perform (‘please perform the following action. . . ’)
• tell (‘it is true that. . . ’)
• reply (‘the answer is . . . ’)
KQML: The 3 Layers
Communication Layer
Mechanics of communication, e.g. Sender, receiver
Performatives (Message Layer)
Specifies the actual content of the messagee.g. a KIF expression
Content Layer
Logic of communication, The set of performatives provided by the language e.g. ask, tell
KQML Example
(ask-one
: content (PRICE IBM ?price)
: receiver stock-server
: language LPROLOG
: ontology NYSE-TICKS 1
)
The intuitive interpretation of this message is that the sender is asking
about the price of IBM stock
The Foundation for Intelligent Physical Agents (FIPA) In 1995, the Foundation for Intelligent Physical Agents (FIPA) began its work
on developing standards for agent systems
The Foundation for Intelligent Physical Agents (FIPA) is a non-profit
association
FIPA’s purpose is to promote the success of emerging agent-based
applications, services and equipment
FIPA operates through the open international collaboration of member
organisations: companies, universities and government organisations
The most important difference between the KQML & FIPA is in the
collection of performatives they provide
FIPA
Here is an example of a I FIPA ACL message
( inform
:sender agent1
: receiver agent2
:content (price good2 150)
:language sl
: onto1ogy hpl –auction
)