To investigate the evacuation behaviors of pedestrians considering the action of guards and to develop an effective evacuation strategy in an artificial attack, an extended floor field model is proposed. In this model...To investigate the evacuation behaviors of pedestrians considering the action of guards and to develop an effective evacuation strategy in an artificial attack, an extended floor field model is proposed. In this model, the artificial attacker's assault on pedestrians, the death of pedestrians, and the guard's capture are involved simultaneously. An alternative evacuation strategy which can largely reduce the number of casualties is developed and the effects of several key parameters such as the deterrence radius and capture distance on evacuation dynamics are studied. The results show that congestion near the exit has dual effects. More specifically, the guard can catch all attackers in a short time because the artificial attackers have a more concentrated distribution, but more casualties can occur because it is hard for pedestrians to escape the assault due to congestion. In contrast, when pedestrians have more preference of approaching the guard, although the guard will take more time to capture the attackers resulting from the dispersion of the attackers, the death toll will decrease. One of the reasons is the dispersal of the crowd, and the decrease in congestion is beneficial for escape. The other is that the attackers will be caught before launching the attack on the people who are around the guard, in other words, the guard protects a large number of pedestrians from being killed. Moreover, increasing capture distance of the guard can effectively reduce the casualties and the catch time. As the deterrence radius reflecting the tendency of escaping from the guard for attackers rises, it becomes more difficult for the guard to catch the attackers and more casualties are caused. However, when the deterrence radius reaches a certain level, the number of deaths is reduced because the attackers prefer to stay as far away as possible from the guard rather than occupy a position where they could assault more people.展开更多
Despite the growing interest in macroscopic epidemiological models to deal with threats posed by pandemics such as COVID-19,little has been done regarding the assessment of disease spread in day-to-day life,especially...Despite the growing interest in macroscopic epidemiological models to deal with threats posed by pandemics such as COVID-19,little has been done regarding the assessment of disease spread in day-to-day life,especially within buildings such as supermarkets where people must obtain necessities at the risk of exposure to disease.Here,we propose an integrated customer shopping simulator including both shopper movement and choice behavior,using a force-based and discrete choice model,respectively.By a simple extension to the force-based model,we implement the following preventive measures currently taken by supermarkets;social distancing and one-way systems,and different customer habits,assessing them based on the average individual disease exposure and the time taken to complete shopping(shopping efficiency).Results show that maintaining social distance is an effective way to reduce exposure,but at the cost of shopping efficiency.We find that the one-way system is the optimal strategy for reducing exposure while minimizing the impact on shopping efficiency.Customers should also visit supermarkets less frequently,but buy more when they do,if they wish to minimize their exposure.We hope that this work demonstrates the potential of pedestrian dynamics simulations in assessing preventative measures during pandemics,particularly if it is validated using empirical data.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFC0804900)the National Natural Science Foundation of China(Grant Nos.71790613 and 51534008)
文摘To investigate the evacuation behaviors of pedestrians considering the action of guards and to develop an effective evacuation strategy in an artificial attack, an extended floor field model is proposed. In this model, the artificial attacker's assault on pedestrians, the death of pedestrians, and the guard's capture are involved simultaneously. An alternative evacuation strategy which can largely reduce the number of casualties is developed and the effects of several key parameters such as the deterrence radius and capture distance on evacuation dynamics are studied. The results show that congestion near the exit has dual effects. More specifically, the guard can catch all attackers in a short time because the artificial attackers have a more concentrated distribution, but more casualties can occur because it is hard for pedestrians to escape the assault due to congestion. In contrast, when pedestrians have more preference of approaching the guard, although the guard will take more time to capture the attackers resulting from the dispersion of the attackers, the death toll will decrease. One of the reasons is the dispersal of the crowd, and the decrease in congestion is beneficial for escape. The other is that the attackers will be caught before launching the attack on the people who are around the guard, in other words, the guard protects a large number of pedestrians from being killed. Moreover, increasing capture distance of the guard can effectively reduce the casualties and the catch time. As the deterrence radius reflecting the tendency of escaping from the guard for attackers rises, it becomes more difficult for the guard to catch the attackers and more casualties are caused. However, when the deterrence radius reaches a certain level, the number of deaths is reduced because the attackers prefer to stay as far away as possible from the guard rather than occupy a position where they could assault more people.
基金Project supported by the China Scholarship Council(Grant No.201906370050).
文摘Despite the growing interest in macroscopic epidemiological models to deal with threats posed by pandemics such as COVID-19,little has been done regarding the assessment of disease spread in day-to-day life,especially within buildings such as supermarkets where people must obtain necessities at the risk of exposure to disease.Here,we propose an integrated customer shopping simulator including both shopper movement and choice behavior,using a force-based and discrete choice model,respectively.By a simple extension to the force-based model,we implement the following preventive measures currently taken by supermarkets;social distancing and one-way systems,and different customer habits,assessing them based on the average individual disease exposure and the time taken to complete shopping(shopping efficiency).Results show that maintaining social distance is an effective way to reduce exposure,but at the cost of shopping efficiency.We find that the one-way system is the optimal strategy for reducing exposure while minimizing the impact on shopping efficiency.Customers should also visit supermarkets less frequently,but buy more when they do,if they wish to minimize their exposure.We hope that this work demonstrates the potential of pedestrian dynamics simulations in assessing preventative measures during pandemics,particularly if it is validated using empirical data.
