AGENT COORDINATION PRESENTATIONEvans TariseGilbert MahlanguArtmas MagomoJustin MakotaINTRODUCTIONAgents in a multiagent system cannot be assumed to share a common goal, as they will often be designed by diferent individuals or organizations in order to reresent their interests! "ne agent#s interests may therefore con$ict with those of others, %ust as in human societies! &esite the otential for con$icts of interest, the agents in a multiagent system will ultimately need to cooerate in order to achieve their goals' again, %ust as in human societiesDefnition: Agent Coordination.(oordination is a secial case of interaction in which agents are aware how they deend on other agents and attemt to ad%ust their actions aroriately! !!"r (oordination is the rocess of managing inter)deendencies between agents* activities! +ecause agents are assumed to be acting autonomously ,and so making decisions about what to do at run time, rather than having all decisions hardwired in at design time-, they must be caable of dynamically coordinating their activities and cooerating with others!(oordination in multiagent systems is assumed to haen at run time, that is, the agents themselves must be caable of recognizing these relationshis and, where necessary, managing them as art of their activities ,von Martial, .//0-!The coordination roblem is that of managing inter)deendencies between the activities of agents1 some coordination mechanism is essential if the activities that agents can engage in can interact in any way! 2ow might two activities interact3Consider the following realworld e!a"#les4ou and 5 both want to leave the room, and so we indeendently walk towards the door, which can only 6t one of us! 5 graciously ermit you to leave 6rst! 5n this e7amle, our activities need to be coordinated because there is a resource ,the door- which we both wish to use, but which can only be used by one erson at a timeDi"ensions of Agent Coordination.Edmund &urfee characterizes three dimension of scaling u agent coordination namely1 agent oulation, task environment, and the solution roerties! 2e argues that an e8cient coordination mechanism needs to address all three dimensions of coordinationAgent Po#%lation Pro#ertiesAgent oulation roerties include number of articiating agents' comle7ity i!e! how comle7 they are in their architectures and internal reasoning mechanism' and heterogeneity of communication languages, ontological and internal architectures! 2ere coordination without having temoral constraints may lead to serious delays and erformance degradation as the increase inthe number of agents ,diversity and comle7ity would also re9uire an increase in coordination time ,ifit is left to function on its sace!Tas& En'iron"ent Pro#ertiesTask environment roerties are about de6ning how an environment in$uences overall coordination task! Main characteristics of agent environment include the degree of interaction between articiating agents' Environment dynamics and distributivity of agents in the environment obviously re9uire a coordination solution having :real)time; factor! 5n other cases resulting coordination may turn not only inefective due to normal ace of interaction but also irrelevant due to environmental dynamics and dynamics and distributivity of agents!Sol%tion Pro#ertieson Martial ,.//?- suggested a tyology for coordination relationshis ,see the 6gure below! 2e suggested that, broadly, relationshis between activities could be either positive or negativeNegati'e )%ltiagent Relationshi#@egative multiagent lan relationshis are all those relationshis between lans, which may revent one or both of the lans from being e7ecuted as intended! They may involve an incomatible ste order, or incomatible resource use, which may lead to con$icts during the lan e7ecution! The detection of negative relationshi is crucial for successful lan e7ecution! @egative relationshis can be distinguished whether their origin is a resource ,sychical- or an incomatible situation ,logical-Cont..Reso%r,e Ind%,ed Con-i,tsTwo lans are in a resource driven negative relationshi if both lans re9uire more from the same resources than is available at the re9uired time! Aesources con$icts between multiagent lans can occur only if a restricted resource is needed by several agents at the same time!Two ,lasses of reso%r,es are re,ogni.ed:Cons%"a/le reso%r,esA resource is consumable if its usability decreases after it has been used in a lan! Ae9uirements for consumable resources are likely to cause a con$ict when the amount of the resource, needed by the agents, e7ceeds the amount available to the agents! "f course the time eriod re9uirements have to be considered!NonCons%"a/le reso%r,esA resource is nonconsumable if its availability does not change after it has been used in a lan! The usability of a nonconsumable resource to the agents is limited through its caacity! A nonconsumable resource is likely to cause a con$ict if it is re9uired beyond its availability over a 67ed eriod of time!In,o"#ati/ilit+Two diferent lans might have goals that re9uire e7clusive states to e7ist ,mutually e7clusive states-' the states involved are incomatible with each other! Bhereas in the resources driven case the reason for con$icts is hysical, here the nature of the reason is logical! The detection of mutually e7clusive states or in comatible actions can be very hard!Positi'e )%ltiagent Relationshi#Cositive relationshis #are all those relationshis between two lans from which some bene6t can be derived, for one or both of the agents lans, by combining them# ,von Martial, .//?, ! ...-! They allow for the roduction of a more e8cient lan! on Martial ,.//?, ! ..0- distinguishes three tyes of non)re9uested relationshi as follows!The a,tion e0%alit+ relationshi#. Be both lan to erform an identical action, and by recognizing this, one of us can erform the action alone and so save the other efort!The ,onse0%en,e relationshi#. The actions in my lan have the side)efect of achieving one of your goals, thus relieving you of the need to e7licitly achieve it!The fa'o%r relationshi#.