关键词: 多主体仿真, 合作搜救, 截断性莱维游走, 拍卖机制, 滑坡

Abstract: In this paper, an agent-based environment is established to simulate the search and rescue after disaster. Two types of active agents are included in this model, namely victims and rescue teams. The improved Truncated Lévy walks model was adopted to simulate rescuers' search behaviors, and an auction algorithm was used to imitate the rescuers' cooperation. The victim agents have a property, i.e., survival probability. Without timely rescue, the health condition of a victim could deteriorate continuously, thus the survival probability will decrease with time, and they may be dead as time passes. The rescue teams search victims in the disaster area, and the rescue teams who locate the buried site take on the role of auctioneers. Other rescue teams who are not at work presently within the scope of cooperation take on the role of bidders. The auctioneers will choose some bidders to cooperate with if necessary. In this paper, the disaster mitigation in adisaster-prone area where landslides occurred frequently is taken as the case to evaluate the performance of proposed scheme. The shapefiles of this area are imported in NetLogo, and the path information is considered in the scheme. To verify the effectiveness of the proposed search and rescue scheme, it is simulated in three scenarios, including "fatal", "serious" and "normal". The simulation results indicate that the cooperative rescue plan would improve victims' relative survival rate by 8.0%-14.5%, improve the ratio of rescued victims to all alive victims by 7.4%-16.7%, and decrease the average elapsed time for one site getting rescued by 25%-26.7%. Moreover, our auction-based approach is as good as the well-known algorithm F-Max-Sum in view of the simulation results, and its low-complexity has made it more appropriate for the cooperation among rescue teams in disaster relief than F-Max-Sum. The robustness analysis shows that search radius plays an important role in improving the rescue efficiency, thus investments in equipment could be adjusted to increase search radius, bringing about improvement in rescue efficiency. The scope of cooperation does not have a significant effect on rescue efficiency, but it is necessary to keep the scope of cooperation larger than a threshold, thus the rescue teams' request for cooperation can be satisfied and the rescue efficiency can be maintained at a high level. The sensitivity analysis shows that the two parameters, the time limit for completing rescue operations in one single site and the maximum turning angle for next step, have great influence on rescue efficiency, and there exist optimal value for both of them in consideration of rescue efficiency.

Key words: multi-agent simulation, cooperative rescue, Truncated Lévy walks, auction, landslide