Given the seriously damaged emergency situation occurring after a large-scale natural disaster, a critical and important problem that needs to be solved urgently is how to distribute the necessary relief goods, such a...Given the seriously damaged emergency situation occurring after a large-scale natural disaster, a critical and important problem that needs to be solved urgently is how to distribute the necessary relief goods, such as drinking water, food, and medicine, to the damaged area and how to transport them corresponding to the actual supply and demand situation as quickly as possible. The existing infrastructure, such as traffic roads, bridges, buildings, and other facilities, may suffer from severe damage. Assuming uncertainty related with each road segment’s availability, we formulate a transshipment network flow optimization problem under various types of uncertain situations. In order to express the uncertainty regarding the availability of each road segment, we apply the Monte Carlo simulation technique to generate random networks following certain probability distribution conditions. Then, we solve the model to obtain an optimal transport strategy for the relief goods. Thus, we try to implement a necessary and desirable response strategy for managing emergency cases caused by, for example, various natural disasters. Our modeling approach was then applied to the actual road network in Sumatra Island in Indonesia in 2009, when a disastrous earthquake occurred to develop effective and efficient public policies for emergency situations.展开更多
The researcher network that appeared in research projects funded by the Japanese government was analyzed. Several static and dynamic network analysis methods were applied to the data for 20 years to explore the fine s...The researcher network that appeared in research projects funded by the Japanese government was analyzed. Several static and dynamic network analysis methods were applied to the data for 20 years to explore the fine structure of the researcher’s network for grants. Our analysis shows that the long-term trend of researchers’ group sizes has become smaller, particularly rapidly decreasing in recent years. Some findings on researcher behavior in joining a project have also been reported.展开更多
This paper studies the use of multiple unmanned aerial vehicles(UAVs)for searching a victim of disaster.We propose a network-based optimization model for planning the search path of multiple UAVs in a disaster-stricke...This paper studies the use of multiple unmanned aerial vehicles(UAVs)for searching a victim of disaster.We propose a network-based optimization model for planning the search path of multiple UAVs in a disaster-stricken area and estimating the number of UAVs necessary for search.A heuristic algorithm is devised to solve the optimization model and applied to the problem instances taken from potential hazard areas in Japan.Our computational result shows relatively small number of UAVs is enough to cover the area in most of cases.We also give an investigation on the relation between search area and the number of UAVs necessary for search via regression methods.展开更多
文摘Given the seriously damaged emergency situation occurring after a large-scale natural disaster, a critical and important problem that needs to be solved urgently is how to distribute the necessary relief goods, such as drinking water, food, and medicine, to the damaged area and how to transport them corresponding to the actual supply and demand situation as quickly as possible. The existing infrastructure, such as traffic roads, bridges, buildings, and other facilities, may suffer from severe damage. Assuming uncertainty related with each road segment’s availability, we formulate a transshipment network flow optimization problem under various types of uncertain situations. In order to express the uncertainty regarding the availability of each road segment, we apply the Monte Carlo simulation technique to generate random networks following certain probability distribution conditions. Then, we solve the model to obtain an optimal transport strategy for the relief goods. Thus, we try to implement a necessary and desirable response strategy for managing emergency cases caused by, for example, various natural disasters. Our modeling approach was then applied to the actual road network in Sumatra Island in Indonesia in 2009, when a disastrous earthquake occurred to develop effective and efficient public policies for emergency situations.
文摘The researcher network that appeared in research projects funded by the Japanese government was analyzed. Several static and dynamic network analysis methods were applied to the data for 20 years to explore the fine structure of the researcher’s network for grants. Our analysis shows that the long-term trend of researchers’ group sizes has become smaller, particularly rapidly decreasing in recent years. Some findings on researcher behavior in joining a project have also been reported.
基金This work is supported by JSPS KAKENHI(Nos.JP17K01285 and JP18K04602)。
文摘This paper studies the use of multiple unmanned aerial vehicles(UAVs)for searching a victim of disaster.We propose a network-based optimization model for planning the search path of multiple UAVs in a disaster-stricken area and estimating the number of UAVs necessary for search.A heuristic algorithm is devised to solve the optimization model and applied to the problem instances taken from potential hazard areas in Japan.Our computational result shows relatively small number of UAVs is enough to cover the area in most of cases.We also give an investigation on the relation between search area and the number of UAVs necessary for search via regression methods.
