Research On Theory And Its Application In WSN Task Assignment Of Agents Coalition Formation In Mulit-agent System Based On PSO

The coalition of agents is a difficult and urgent problem in multi-agent system(MAS).How to form a highly stable,efficient and balanced coalition in the best direction is one of key problems in MAS.Due to its simple search,good distribution and strong global optimization,the PSO algorithm is often used to solve the problem of coalition formation.But disadvantage of the PSO algorithm is easy to fall into local optimum,the low search efficiency,which will inevitably affect the optimal coalition value.After research the related problem about the theory of MAS coalition formation and PSO algorithm,the paper further study on the agent dynamic coalition formation and its application in WSN task assignment based on PSO,the main concrete work includes:(1)Proposed a multiple agent coalition formation method based on IPSO algorithm.Considering the single agent ability finiteness,multiple agents often need to form a coalition to accomplish a task or improve the whole ability of coalition.The primary issue when oriented a set of tasks in MAS is how to generate an optimal coalition.Based on this background,this paper put forward an improved particle swarm optimization algorithm(IPSO)to solve the problem.In order to overcome the particle premature convergence and local optimization problems,a Cauchy mutation disturbance operator was introduced.Compared with PSO algorithm and the ACO algorithm,the global optimization of IPSO algorithm is better,which effectively avoided the premature convergence,resources wasting problems and so on.(2)Based on agent's own outstanding characteristics,the paper put forward a novel utility allocation strategy.To improve features among coalition members in MAS and at the same time guarantee the rationality of the utility distribution,against the background of BDI model,this paper is put forward a novel coalition utility allocation policy based on the agent's own outstanding characteristics.According to different requirements of task,agents are eager to update their outstanding characteristics timely in order to maximize their own benefit,ensure friendly co-operation with other members and also finish the task efficiency.The theoretical analysis and experiments showed that the novel strategy could improve agents' adaptation to environment,basically satisfy the global optimal solution,strong stability,the reasonable allocation of benefit among agents and timeliness etc.(3)Based on the role model of agents and WSN task allocation problem,the paper proposed a mixed coalition task allocation strategy,which was also a practical application of the theory in MAS coalition.As most of the existing task allocation strategies for wireless sensor networks seldom considered the internal structure of tasks,which may largely affectthe network lifetime,energy consumption and load balance,etc.The paper proposed a novel wireless sensor network(WSN)task allocation strategy based the logical dependencies.First,the task was decomposed step by step which was made of sub-tasks by the elected leaders according to the logical dependency,and at the same time give sub-tasks priority based on the logical dependence.Last using the matrix a binary coding,the paper proposed a wireless sensor network(WSN)task allocation strategy about the discrete particle swarm optimization algorithm based on the weighted location with mixed coalition until they found a suitable node to perform the sub-task.To enhance the communication between the elected leaders,some virtual nodes were introduced;to estimate the residual node energy,the estimated energy value was introduced to decide whether the sub-task is migration or not.What's more,according to the expected completion time and weight coefficient of sub-tasks,the paper sorted out the key sub-task by using topological sort and inverse topological,and also the key sub-task was assigned by strong ability,high execution nodes to complete.Finally,the experimental results showed that the novel task allocation strategy could effectively prolong the network lifetime,a steady balance of network load and reduce the energy consumption,etc.