Communication in Multi-Agent Systems (MAS) Sohel Merchant MAPLE Group CSEE Department University of Maryland Baltimore County
Outline Agent Communication Agent Communication languages Communication in Herding scenario Communication Models Messages Current and Future work
Agent Communication Central to the Agent oriented paradigm Used to convey across knowledge and information. Enables Co-ordination Co-operation Negotiation
Agent Communication languages KQML Independent of transport mechanism, content language and ontology A KQML message contains a performative / speech act, semantics and an attribute/value pairs FIPA ACL Syntax similar to KQML Messages are communicative actions
FIPA ACL Message structure Performatives Describes the type of communicative act. Sender Receiver Reply-to Content Language
FIPA ACL Message structure Encoding Ontology Protocol Conversation-id Reply-with In-reply-to Reply-by
Herding Scenario Basic states Wander/Search Align Herd Each agent is in one of the above state at any instant of time. Goal is to herd enemy agent to the home base
Communication in Herding Scenario Why do you need communication ? Co-ordination If an agent identifies that evaders are segregated in a particular region then it will send “Help” messages to agents in its communication range On receiving this message fellow co-operating agents can decide to go to that region and herd enemy agents.
Communication Models Distance Obstacles Noise Probability of messages being received depends upon the distance between agents. F(x) = 1/x Where x is the distance Obstacles signals can be attenuated due to presence of obstacles. Noise Noise in the environment may garble the messages.
Messages Help Used to ask for help Ack Sent in reply to a message.
Dump of Help Message <ACLMessage> <Domain>Herding</Domain> <Sender>agentid</Sender> <Receiver>agentid</ Receiver> <Content> <Message-type>Help</ Message type> <Position>x,y,r,t</Position> </Content> </ACLMessage>
Current and Future work Extend the basic herding scenario. Include a Formation state. Facilitates herding more than one agent by a group of agents. Co-operation
Current and Future work 4 agents herding one or more agents Home Base
Current and Future work Dynamic Organization Emergency Rescue RoboCup rescue Extension of RoboCup soccer Applied to disaster relief A.R.E.S
Thank-you