Tomofumi Matsuzawa

An Improved Evacuation Guidance System Based on Ant Colony Optimization

This paper proposes an evacuation guidance method for use in disaster situations. The method is based on ant colony optimization (ACO). We have implemented the method as ACO-based evacuation system in a simulator and examined the feasibility of the system. Since we cannot depend on the communication infrastructures with a disaster occurs, we make the system utilize mobile ad hoc network (MANET). We expect the ACO-based evacuation system produces quasi-optimized evacuation paths by the cooperation of multiple agents, while MANET provides communication between agents in the environment lacking of network infrastructure. Even though a number of ACO-based guidance systems have been developed, there are still some questions whether evacuees who follow the evacuation paths given by ACO are really safe. We examined how safe following these paths is by simulations, and found that they were not safe in some cases. As a result, in this paper, we propose an improved ACO-based evacuation system that equips deodorant pheromone to actively erase ACO pheromone traces when dangerous locations are found. Our simulation results show the use of deodorant pheromone can improve the safety level of the evacuation guidance system without degrading evacuation efficiency.

Multi-Agent Approach for Evacuation Support System.

We propose a system that supports evacuation after a large-scale disaster. When a large-scale disaster occurs, collecting information by using portable devices is difficult, because communication base stations collapse and traffic congestion occurs. Evacuees are at a loss where they should go for safe places in lack of information. In order to overcome these problems, we have proposed and evaluated a multi-agent system that is built on MANET. Our aim is to let the users share information on MANET, and provide safe routes to the destination by using collected information. In the previous paper, we proposed and implemented the main functions of the proposed system, and performed feasibility study of the multi-agent system by using simple simulator. In this paper, we report the revised system and investigate the relationships between the number of the users and diffusivity of information, and the number of the generated mobile agents by using newly constructed simulator. In the experiments for evaluation, we simulated a realistic situation by using real map data and we took stochastic change of the situation into consideration, because the situation must be getting worse by time elapses.

Multi-agent Approach for Return Route Support System Simulation

We propose a system that supports stranded commuters caused by a large-scale disaster. When a large-scale disaster breaks out, buildings may collapse and roads may be damaged and the public transportation systems would be paralyzed. Thus, people working in the city center have to walk back home on foot. The problem is that when those people start walking, the situation along the routes for returning home may be different from that of the pre-disaster. Not only may it be the first time for most of them to walk home, but also the return route may be extremely complex due to many detours. They have to look for alternative routes whenever bridges collapse and fires break out. Making situation become worse, modern people intensively use navigation systems, those systems may be unavailable due to the paralyzed Internet. A large scale disaster may destroy base stations of wireless phones, and even if it does not completely destroy them, extreme congestion may paralyze the communication infrastructure so that not only net-surfing using smartphone, but also collecting information by e-mail may become impossible. To deal with such situations, we are designing a system that provides those unfortunate pedestrians appropriate return routes to their homes without depending on the communication infrastructures. Instead, our proposed system only depends on smartphones of those pedestrians and constructs mobile ad hoc networks (MANET) to collect and disperse useful information. We employ multiple mobile agents extensively for information collection and dispersion. In order to demonstrate the feasibility of our system, we have constructed a preliminary prototype of the simulation system and have conducted numerical experiments.

An Implementation of an Ad Hoc Mobile Multi-agent System for a Safety Information

Mobile Ad hoc Network (MANET) is a network that connects mobile devices without any central control. Since MANET is an infrastructure-less network that consists of only mobile devices, it should be convenient means to construct temporary networks as a part of contingency plan (when a disaster occurs). In this paper, we report our experience that we have obtained through our design and implementation of a mobile software agent system running on mobile ad hoc network. In order to demonstrate the usefulness of the mobile software agent system, we have implemented a safety information collection system for sufferers of a disaster as an example application. Our experience suggests that the combination of mobile software agents and ad hoc network open the new horizon of temporary communication system without infrastructure.