An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street blocks.Hazard sources not only physically but psychologically affect the ped...An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street blocks.Hazard sources not only physically but psychologically affect the pedestrians,which may further alter their behavioral patterns.This effect is especially significant in narrow spaces,such as corridors and alleys.This study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment and simulation,and to simulate unidirectional pedestrian flows over various crowd densities and clarity–intensity properties of the hazard source.The integration include a virtual repulsion force from the hazard source and a decay on the social force term.The simulations reveal(i)that the hazard source creates virtual bottlenecks that suppress the flow,(ii)that the inter-pedestrian push forms a stabilisation phase on the flow-density curve within medium-to-high densities,and(iii)that the pedestrians are prone to a less orderly and stable pattern of movement in low clarity–intensity scenarios,possibly with lateral collisions passing the hazard source.展开更多
The subway is the primary travel tool for urban residents in China. Due to the complex structure of the subway and high personnel density in rush hours, subway evacuation capacity is critical. The subway evacuation mo...The subway is the primary travel tool for urban residents in China. Due to the complex structure of the subway and high personnel density in rush hours, subway evacuation capacity is critical. The subway evacuation model is explored in this work by combining the improved social force model with the view radius using the Vicsek model. The pedestrians are divided into two categories based on different force models. The first category is sensitive pedestrians who have normal responses to emergency signs. The second category is insensitive pedestrians. By simulating different proportions of the insensitive pedestrians, we find that the escape time is directly proportional to the number of insensitive pedestrians and inversely proportional to the view radius. However, when the view radius is large enough, the escape time does not change significantly, and the evacuation of people in a small view radius environment tends to be integrated. With the improvement of view radius conditions, the escape time changes more obviously with the proportion of insensitive pedestrians. A new emergency sign layout is proposed, and the simulations show that the proposed layout can effectively reduce the escape time in a small view radius environment. However, the evacuation effect of the new escape sign layout on the large view radius environment is not apparent. In this case, the exit setting emerges as an additional factor affecting the escape time.展开更多
In the process of crowd movement,pedestrians are often affected by their neighbors.In order to describe the consistency of adjacent individuals and collectivity of a group,this paper learns from the rules of the flock...In the process of crowd movement,pedestrians are often affected by their neighbors.In order to describe the consistency of adjacent individuals and collectivity of a group,this paper learns from the rules of the flocking behavior,such as segregation,alignment and cohesion,and proposes a method for crowd motion simulation based on the Boids model and social force model.Firstly,the perception area of individuals is divided into zone of segregation,alignment and cohesion.Secondly,the interactive force among individuals is calculated based upon the zone information,velocity vector and the group information.The interactive force among individuals is the synthesis of three forces:the repulsion force to avoid collisions,the alignment force to keep consistent with the velocity direction,and the attractive force to get close to the members of group.In segregation and alignment areas,the repulsion force and alignment force among pedestrians are limited by visual field factors.Finally,the interactive force among individuals,the driving force of destination and the repulsion force of obstacles work together to drive the behavior of crowd motion.The simulation results show that the proposed method can not only effectively simulate the interactive behavior between adjacent individuals but also the collective behavior of group.展开更多
Objective To provide a reference and suggestions for Chinese social forces to participate in the emergency management of public health events.Methods Through literature research method,comparative research method and ...Objective To provide a reference and suggestions for Chinese social forces to participate in the emergency management of public health events.Methods Through literature research method,comparative research method and SWOT matrix analysis,four aspects of prevention,early warning,response and recovery of the social forces in China,Germany,Australia and the United States participating in emergency management were studied comparatively.Results and Conclusion In the emergency management of public health events,China’s social forces play greater role in the response and recovery phase than that in the prevention and response phase.As to its shortcomings,the following suggestions are made,such as incorporating social forces into the national emergency management system,strengthening the construction and training of social forces,popularizing public health knowledge and awareness,clarifying property rights and using incentives and punishment together.展开更多
Crowd evacuation simulation using virtual reality(VR)is significant for digital emergency response construction.However,existing evacuation simulation studies suffer from poor adaptation to complex environments,ineffi...Crowd evacuation simulation using virtual reality(VR)is significant for digital emergency response construction.However,existing evacuation simulation studies suffer from poor adaptation to complex environments,inefficient evacuations,and poor simulation effects and do not fully consider the impacts of specific disaster environments on crowd evacuation.To more realistically express the crowd evacuation results obtained under the influence offire environments and the subjective consciousness of pedestrians in subway stations,we designed a dynamic pedestrian evacuation path planning method under multiple constraints,analysed the influences of an‘environmental role’and a‘subjective initiative’on crowd evacuation,established an improved social force model(ISFM)-based crowd evacuation simulation method in VR,developed a prototype system and conducted experimental analyses.The experimental results show that the crowd evacuation time of the ISFM is affected by the disaster severity.In simulation experiments without disaster scenarios,the improved model’s crowd evacuation efficiency improved by averages of 12.53%and 15.37%over the commercial Pathfinder software and the original social force model,respectively.The method described herein can effectively support real-time VR crowd evacuation simulation under multiexit and multifloor conditions and can provide technical support for emergency evacuation learning and management decision analyses involving subwayfires.展开更多
With the increase in large-scale incidents in real life, crowd evacuation plays a pivotal role in ensuring the safety of human crowds during emergency situations. The behavior patterns of crowds are well rendered by e...With the increase in large-scale incidents in real life, crowd evacuation plays a pivotal role in ensuring the safety of human crowds during emergency situations. The behavior patterns of crowds are well rendered by existing crowd dynamics models. However, most related studies ignore the information perception of pedestrians.To overcome this issue, we develop a visual information based social force model to simulate the interpretable evacuation process from the perspective of visual perception. Numerical experiments indicate that the evacuation efficiency and decision-making ability promote rapidly within a small range with the increase in unbalanced prior knowledge. The propagation of acceleration behavior caused by emergencies is asymmetric due to the anisotropy of visual information. Therefore, this model effectively characterizes the effect of visual information on crowd evacuation and provides new insights into the information perception of individuals in complex scenarios.展开更多
The social force model has been widely used to simulate pedestrian evacuation by analyzing attractive,repulsive,driving,and fluctuating forces among pedestrians.Many researchers have improved its limitations in simula...The social force model has been widely used to simulate pedestrian evacuation by analyzing attractive,repulsive,driving,and fluctuating forces among pedestrians.Many researchers have improved its limitations in simulating behaviors of large-scale population.This study modifies the well-accepted social force model by considering the impacts of interaction among companions and further develops a comprehensive model by combining that with a multi-exit utility function.Then numerical simulations of evacuations based on the comprehensive model are implemented in the waiting hall of the Wulin Square Subway Station in Hangzhou,China.The results provide safety thresholds of pedestrian density and panic levels in different operation situations.In spite of the operation situation and the panic level,a larger friend-group size results in lower evacuation efficiency.Our study makes important contributions to building a comprehensive multi-exit social force model and to applying it to actual scenarios,which produces data to facilitate decision making in contingency plans and emergency treatment.展开更多
Under the background of Covid-19 sweeping the world,safe and reasonable passenger flow management strategy in subway stations is an effective means to prevent the spread of virus.Based on the social force model and th...Under the background of Covid-19 sweeping the world,safe and reasonable passenger flow management strategy in subway stations is an effective means to prevent the spread of virus.Based on the social force model and the minimum cost model,the movement and path selection behavior of passengers in the subway station are modeled,and a strategy for passenger flow management to maintain a safe social distance is put forward.Take Qingdao Jinggangshan Road subway station of China as the simulation scene,the validity of the simulation model is verified by comparing the measured value and simulation value of the time required for passengers from getting off the train to the ticket gate.Simulation results indicate that controlling the time interval between incoming passengers at the entrance can effectively control the social distance between passengers and reduce the risk of epidemic infection.By comparing the evacuation process of passengers under different initial densities,it is found that the greater the initial density of passengers is,the longer the passengers are at risk social distance.In the process of passenger emergency evacuation,the stairs/escalators and ticket gates are bottleneck areas with high concentration of passenger density,which should be strictly disinfected many times on the basis of strictly checking the health code of incoming passengers and controlling the arrival time interval.The simulation results of this paper verify the harmfulness of passenger emergency evacuation without protective measures,and provide theoretical support for the operation and management of subway station under the epidemic situation.展开更多
Selecting the optimal speed for dynamic obstacle avoidance in complex man–machine environments is a challenging problem for mobile robots inspecting hazardous gases.Consideration of personal space is important,especi...Selecting the optimal speed for dynamic obstacle avoidance in complex man–machine environments is a challenging problem for mobile robots inspecting hazardous gases.Consideration of personal space is important,especially in a relatively narrow man–machine dynamic environments such as warehouses and laboratories.In this study,human and robot behaviors in man–machine environments are analyzed,and a man–machine social force model is established to study the robot obstacle avoidance speed.Four typical man–machine behavior patterns are investigated to design the robot behavior strategy.Based on the social force model and man–machine behavior patterns,the fuzzy-PID trajectory tracking control method and the autonomous obstacle avoidance behavior strategy of the mobile robot in inspecting hazardous gases in a relatively narrow man–machine dynamic environment are proposed to determine the optimal robot speed for obstacle avoidance.The simulation analysis results show that compared with the traditional PID control method,the proposed controller has a position error of less than 0.098 m,an angle error of less than 0.088 rad,a smaller steady-state error,and a shorter convergence time.The crossing and encountering pattern experiment results show that the proposed behavior strategy ensures that the robot maintains a safe distance from humans while performing trajectory tracking.This research proposes a combination autonomous behavior strategy for mobile robots inspecting hazardous gases,ensuring that the robot maintains the optimal speed to achieve dynamic obstacle avoidance,reducing human anxiety and increasing comfort in a relatively narrow man–machine environment.展开更多
Grouping is a common phenomenon that occurs everywhere.The leader-follower relationship inside groups has often been qualitatively characterized in previous models using simple heuristics.However,a general method is l...Grouping is a common phenomenon that occurs everywhere.The leader-follower relationship inside groups has often been qualitatively characterized in previous models using simple heuristics.However,a general method is lacking to quantitatively explain leadership in an evacuating group.To understand the evolution of single-group dynamics throughout an evacuation,we developed an extended social force model integrated with a group force.A series of single-group evacuations from a room were simulated.An information-theoretic method,transfer entropy(TE),was applied to detect predefined and undeclared leadership among evacuees.The results showed that the predefined leader was correctly detected by TE,suggesting its capability in measuring leadership based on time series of evacuees’movement information(e.g.,velocity and acceleration).When evacuees were grouped together,TE was higher than when they were alone.Leaders presented a monotonically increasing cumulative influence curve over the investigated period,whereas followers showed a diminishing tendency.We found that leadership emergence correlated with evacuees’spatial positions.The individual located in the foremost part of the group was most likely to become a leader of those in the rear,which concurred with the experimental observations.We observed how a large group split into smaller ones with undeclared leadership during evacuation.These observations were quantitatively verified by TE results.This study provides novel insights into quantifying leadership and understanding single-group dynamics during evacuations.展开更多
In dense crowd evacuation,especially in emergencies such as fires,the safe evacuation of large public facilities will face major challenges.At the same time,as cluster congestion tends to occur in the space where the ...In dense crowd evacuation,especially in emergencies such as fires,the safe evacuation of large public facilities will face major challenges.At the same time,as cluster congestion tends to occur in the space where the flow rate drops sharply,the superposition of fire incidents and bottleneck areas can easily evolve into malignant disasters and crowd stampedes with serious harm and influence.In this paper,Massmotion based on social force model is used to carry out a numerical simulation on exit position and corner exit form to find out the mechanism and influence law of the slight architectural adjustment on the flow at bottleneck.The results show that the traditional middle exit design is not the best,and the evacuation efficiency of the corner exit is higher than that of the middle exit.Compared with other corner exits,the average time interval between two adjacent persons passing through the bottleneck under the 30°corner exit is the shortest,and the probability of outlet clogging drops the fastest,exceeding 18%of the slowest descending speed.At the 0°corner exit,the waiting time cost of pedestrians is high and the risk of evacuation is high.The outcomes of this work can provide reference for the structural design of the building and the safe evacuation of personnel,so as to improve the evacuation efficiency and safety of pedestrians in the building to some extent.展开更多
Building exit has always been an emphasis of research in the field of evacuation.Existing studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention...Building exit has always been an emphasis of research in the field of evacuation.Existing studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention has been paid to the characteristics of crowd flow at the convex exit.Convex exit can be considered as such a structure like a double-bottleneck linked passage.This paper aims to study the influence of geometric structure characteristics of the convex exit on crowd evacuation and put forward the optimal design strategy of this structure,so as to improve the efficiency of evacuation in an emergency.Using social force model-based software,MassMotion,it is found that convex exit is indeed more efficient and safer than common plane exit in terms of evacuation time and pedestrians'congestion,especially when the desired speed is relatively higher,indicating that convex exits are more suitable for crowd evacuation in case of emergency.Four size-related parameters of convex exit are analyzed in detail,namely the width of the bottleneck at passage(W_(p)),the passage width(W),the passage length(L),and the exit width(W_(e)),to find out the optimum design of convex exit.The research shows that the optimal size ratio is that Wp:W:L:We equals 1.5:1.75:3.5:1,and as the overall magnification of building size and the number of pedestrians increases,the evacuation time gradually tends to a stable value,which indicates that this optimal ratio has good adaptability in size effect.Finally,based on the in-depth mechanism of pedestrian flow at the convex exit,three possible application scenarios are proposed to illustrate the feasible optimum design of the convex exit.The results of this study can provide new ideas for research on the structure of building exits.展开更多
Research on evacuation simulation and modeling is an important and urgent issue for emergency management.This paper presents an evacuation model based on cellular automata and social force to simulate the evacuation d...Research on evacuation simulation and modeling is an important and urgent issue for emergency management.This paper presents an evacuation model based on cellular automata and social force to simulate the evacuation dynamics.Attractive force of target position,repulsive forces of individuals and obstacles,as well as congestion are considered in order to simulate the interaction among evacuees and the changing environment.A visual-guidance-based artificial bee colony algorithm is proposed to optimize the evacuation process.Each evacuee moves toward exits with the guidance of leading bee in his/her visual field.And leading bee is selected according to comprehensive factors including distance from the current individual,the number of obstacles and congestion,which avoids the randomness of roulette mechanism used by basic artificial bee colony algorithm.The experimental results indicate that the proposed model and algorithm can achieve effective performances for indoor evacuation problems with a large number of evacuees and obstacles,which accords with the actual evacuation situation.展开更多
基金Project supported by National Key Research and Development Program of China(Grant Nos.2022YFC3320800 and 2021YFC1523500)the National Natural Science Foundation of China(Grant Nos.71971126,71673163,72304165,72204136,and 72104123).
文摘An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street blocks.Hazard sources not only physically but psychologically affect the pedestrians,which may further alter their behavioral patterns.This effect is especially significant in narrow spaces,such as corridors and alleys.This study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment and simulation,and to simulate unidirectional pedestrian flows over various crowd densities and clarity–intensity properties of the hazard source.The integration include a virtual repulsion force from the hazard source and a decay on the social force term.The simulations reveal(i)that the hazard source creates virtual bottlenecks that suppress the flow,(ii)that the inter-pedestrian push forms a stabilisation phase on the flow-density curve within medium-to-high densities,and(iii)that the pedestrians are prone to a less orderly and stable pattern of movement in low clarity–intensity scenarios,possibly with lateral collisions passing the hazard source.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51874183 and 51874182)the National Key Research and Development Program of China (Grant No. 2018YFC0809300)。
文摘The subway is the primary travel tool for urban residents in China. Due to the complex structure of the subway and high personnel density in rush hours, subway evacuation capacity is critical. The subway evacuation model is explored in this work by combining the improved social force model with the view radius using the Vicsek model. The pedestrians are divided into two categories based on different force models. The first category is sensitive pedestrians who have normal responses to emergency signs. The second category is insensitive pedestrians. By simulating different proportions of the insensitive pedestrians, we find that the escape time is directly proportional to the number of insensitive pedestrians and inversely proportional to the view radius. However, when the view radius is large enough, the escape time does not change significantly, and the evacuation of people in a small view radius environment tends to be integrated. With the improvement of view radius conditions, the escape time changes more obviously with the proportion of insensitive pedestrians. A new emergency sign layout is proposed, and the simulations show that the proposed layout can effectively reduce the escape time in a small view radius environment. However, the evacuation effect of the new escape sign layout on the large view radius environment is not apparent. In this case, the exit setting emerges as an additional factor affecting the escape time.
文摘In the process of crowd movement,pedestrians are often affected by their neighbors.In order to describe the consistency of adjacent individuals and collectivity of a group,this paper learns from the rules of the flocking behavior,such as segregation,alignment and cohesion,and proposes a method for crowd motion simulation based on the Boids model and social force model.Firstly,the perception area of individuals is divided into zone of segregation,alignment and cohesion.Secondly,the interactive force among individuals is calculated based upon the zone information,velocity vector and the group information.The interactive force among individuals is the synthesis of three forces:the repulsion force to avoid collisions,the alignment force to keep consistent with the velocity direction,and the attractive force to get close to the members of group.In segregation and alignment areas,the repulsion force and alignment force among pedestrians are limited by visual field factors.Finally,the interactive force among individuals,the driving force of destination and the repulsion force of obstacles work together to drive the behavior of crowd motion.The simulation results show that the proposed method can not only effectively simulate the interactive behavior between adjacent individuals but also the collective behavior of group.
基金Key Projects of Shenyang Social Science Fund(No.SYSK2020-04-01).
文摘Objective To provide a reference and suggestions for Chinese social forces to participate in the emergency management of public health events.Methods Through literature research method,comparative research method and SWOT matrix analysis,four aspects of prevention,early warning,response and recovery of the social forces in China,Germany,Australia and the United States participating in emergency management were studied comparatively.Results and Conclusion In the emergency management of public health events,China’s social forces play greater role in the response and recovery phase than that in the prevention and response phase.As to its shortcomings,the following suggestions are made,such as incorporating social forces into the national emergency management system,strengthening the construction and training of social forces,popularizing public health knowledge and awareness,clarifying property rights and using incentives and punishment together.
基金supported by the National Natural Science Foundation of China[grant no 42271424,42171397]Sichuan Transportation Science and Technology Program[grant no 2021-B-02]Chengdu Science and Technology Program[grant no 2021XT00001GX].
文摘Crowd evacuation simulation using virtual reality(VR)is significant for digital emergency response construction.However,existing evacuation simulation studies suffer from poor adaptation to complex environments,inefficient evacuations,and poor simulation effects and do not fully consider the impacts of specific disaster environments on crowd evacuation.To more realistically express the crowd evacuation results obtained under the influence offire environments and the subjective consciousness of pedestrians in subway stations,we designed a dynamic pedestrian evacuation path planning method under multiple constraints,analysed the influences of an‘environmental role’and a‘subjective initiative’on crowd evacuation,established an improved social force model(ISFM)-based crowd evacuation simulation method in VR,developed a prototype system and conducted experimental analyses.The experimental results show that the crowd evacuation time of the ISFM is affected by the disaster severity.In simulation experiments without disaster scenarios,the improved model’s crowd evacuation efficiency improved by averages of 12.53%and 15.37%over the commercial Pathfinder software and the original social force model,respectively.The method described herein can effectively support real-time VR crowd evacuation simulation under multiexit and multifloor conditions and can provide technical support for emergency evacuation learning and management decision analyses involving subwayfires.
基金supported by the National Key Research and Development Program of China (No. 2020YFF0304900)the National Major Scientific Research Instrument Development Project of China (No. 61927804)。
文摘With the increase in large-scale incidents in real life, crowd evacuation plays a pivotal role in ensuring the safety of human crowds during emergency situations. The behavior patterns of crowds are well rendered by existing crowd dynamics models. However, most related studies ignore the information perception of pedestrians.To overcome this issue, we develop a visual information based social force model to simulate the interpretable evacuation process from the perspective of visual perception. Numerical experiments indicate that the evacuation efficiency and decision-making ability promote rapidly within a small range with the increase in unbalanced prior knowledge. The propagation of acceleration behavior caused by emergencies is asymmetric due to the anisotropy of visual information. Therefore, this model effectively characterizes the effect of visual information on crowd evacuation and provides new insights into the information perception of individuals in complex scenarios.
基金Project supported by the National Natural Science Foundation of China(Grant No.71471163)
文摘The social force model has been widely used to simulate pedestrian evacuation by analyzing attractive,repulsive,driving,and fluctuating forces among pedestrians.Many researchers have improved its limitations in simulating behaviors of large-scale population.This study modifies the well-accepted social force model by considering the impacts of interaction among companions and further develops a comprehensive model by combining that with a multi-exit utility function.Then numerical simulations of evacuations based on the comprehensive model are implemented in the waiting hall of the Wulin Square Subway Station in Hangzhou,China.The results provide safety thresholds of pedestrian density and panic levels in different operation situations.In spite of the operation situation and the panic level,a larger friend-group size results in lower evacuation efficiency.Our study makes important contributions to building a comprehensive multi-exit social force model and to applying it to actual scenarios,which produces data to facilitate decision making in contingency plans and emergency treatment.
基金the National Natural Science Foundation of China(Grant No.62003182)。
文摘Under the background of Covid-19 sweeping the world,safe and reasonable passenger flow management strategy in subway stations is an effective means to prevent the spread of virus.Based on the social force model and the minimum cost model,the movement and path selection behavior of passengers in the subway station are modeled,and a strategy for passenger flow management to maintain a safe social distance is put forward.Take Qingdao Jinggangshan Road subway station of China as the simulation scene,the validity of the simulation model is verified by comparing the measured value and simulation value of the time required for passengers from getting off the train to the ticket gate.Simulation results indicate that controlling the time interval between incoming passengers at the entrance can effectively control the social distance between passengers and reduce the risk of epidemic infection.By comparing the evacuation process of passengers under different initial densities,it is found that the greater the initial density of passengers is,the longer the passengers are at risk social distance.In the process of passenger emergency evacuation,the stairs/escalators and ticket gates are bottleneck areas with high concentration of passenger density,which should be strictly disinfected many times on the basis of strictly checking the health code of incoming passengers and controlling the arrival time interval.The simulation results of this paper verify the harmfulness of passenger emergency evacuation without protective measures,and provide theoretical support for the operation and management of subway station under the epidemic situation.
基金Research and Development Program of Xi’an Modern Chemistry Research Institute of Chnia(Grant No.204J201916234/6)Key Project of Liuzhou Science and Technology Bureau of China(Grant No.2020PAAA0601).
文摘Selecting the optimal speed for dynamic obstacle avoidance in complex man–machine environments is a challenging problem for mobile robots inspecting hazardous gases.Consideration of personal space is important,especially in a relatively narrow man–machine dynamic environments such as warehouses and laboratories.In this study,human and robot behaviors in man–machine environments are analyzed,and a man–machine social force model is established to study the robot obstacle avoidance speed.Four typical man–machine behavior patterns are investigated to design the robot behavior strategy.Based on the social force model and man–machine behavior patterns,the fuzzy-PID trajectory tracking control method and the autonomous obstacle avoidance behavior strategy of the mobile robot in inspecting hazardous gases in a relatively narrow man–machine dynamic environment are proposed to determine the optimal robot speed for obstacle avoidance.The simulation analysis results show that compared with the traditional PID control method,the proposed controller has a position error of less than 0.098 m,an angle error of less than 0.088 rad,a smaller steady-state error,and a shorter convergence time.The crossing and encountering pattern experiment results show that the proposed behavior strategy ensures that the robot maintains a safe distance from humans while performing trajectory tracking.This research proposes a combination autonomous behavior strategy for mobile robots inspecting hazardous gases,ensuring that the robot maintains the optimal speed to achieve dynamic obstacle avoidance,reducing human anxiety and increasing comfort in a relatively narrow man–machine environment.
基金The Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.CityU 11208119)a grant from CityU(Project No.SRG-Fd 7005769)supported this study.
文摘Grouping is a common phenomenon that occurs everywhere.The leader-follower relationship inside groups has often been qualitatively characterized in previous models using simple heuristics.However,a general method is lacking to quantitatively explain leadership in an evacuating group.To understand the evolution of single-group dynamics throughout an evacuation,we developed an extended social force model integrated with a group force.A series of single-group evacuations from a room were simulated.An information-theoretic method,transfer entropy(TE),was applied to detect predefined and undeclared leadership among evacuees.The results showed that the predefined leader was correctly detected by TE,suggesting its capability in measuring leadership based on time series of evacuees’movement information(e.g.,velocity and acceleration).When evacuees were grouped together,TE was higher than when they were alone.Leaders presented a monotonically increasing cumulative influence curve over the investigated period,whereas followers showed a diminishing tendency.We found that leadership emergence correlated with evacuees’spatial positions.The individual located in the foremost part of the group was most likely to become a leader of those in the rear,which concurred with the experimental observations.We observed how a large group split into smaller ones with undeclared leadership during evacuation.These observations were quantitatively verified by TE results.This study provides novel insights into quantifying leadership and understanding single-group dynamics during evacuations.
基金This research was sponsored by the National Natural Science Foundation of China(No.71774079)the Major Natural Science Research Projects in Colleges and Universities of Jiangsu Province(No.19KJA460011)+2 种基金the National Natural Science Foundation of China(No.51874182)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX20_0365)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In dense crowd evacuation,especially in emergencies such as fires,the safe evacuation of large public facilities will face major challenges.At the same time,as cluster congestion tends to occur in the space where the flow rate drops sharply,the superposition of fire incidents and bottleneck areas can easily evolve into malignant disasters and crowd stampedes with serious harm and influence.In this paper,Massmotion based on social force model is used to carry out a numerical simulation on exit position and corner exit form to find out the mechanism and influence law of the slight architectural adjustment on the flow at bottleneck.The results show that the traditional middle exit design is not the best,and the evacuation efficiency of the corner exit is higher than that of the middle exit.Compared with other corner exits,the average time interval between two adjacent persons passing through the bottleneck under the 30°corner exit is the shortest,and the probability of outlet clogging drops the fastest,exceeding 18%of the slowest descending speed.At the 0°corner exit,the waiting time cost of pedestrians is high and the risk of evacuation is high.The outcomes of this work can provide reference for the structural design of the building and the safe evacuation of personnel,so as to improve the evacuation efficiency and safety of pedestrians in the building to some extent.
基金This research was sponsored by the National Natural Science Foundation of China(No.71774079)the Major Natural Science Research Projects in Colleges and Universities of Jiangsu Province(No.19KJA460011)+2 种基金the National Natural Science Foundation of China(No.51874182)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX21_0438)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Building exit has always been an emphasis of research in the field of evacuation.Existing studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention has been paid to the characteristics of crowd flow at the convex exit.Convex exit can be considered as such a structure like a double-bottleneck linked passage.This paper aims to study the influence of geometric structure characteristics of the convex exit on crowd evacuation and put forward the optimal design strategy of this structure,so as to improve the efficiency of evacuation in an emergency.Using social force model-based software,MassMotion,it is found that convex exit is indeed more efficient and safer than common plane exit in terms of evacuation time and pedestrians'congestion,especially when the desired speed is relatively higher,indicating that convex exits are more suitable for crowd evacuation in case of emergency.Four size-related parameters of convex exit are analyzed in detail,namely the width of the bottleneck at passage(W_(p)),the passage width(W),the passage length(L),and the exit width(W_(e)),to find out the optimum design of convex exit.The research shows that the optimal size ratio is that Wp:W:L:We equals 1.5:1.75:3.5:1,and as the overall magnification of building size and the number of pedestrians increases,the evacuation time gradually tends to a stable value,which indicates that this optimal ratio has good adaptability in size effect.Finally,based on the in-depth mechanism of pedestrian flow at the convex exit,three possible application scenarios are proposed to illustrate the feasible optimum design of the convex exit.The results of this study can provide new ideas for research on the structure of building exits.
基金This work was supported by the National Natural Science Foundation of China(No.61772180)the Key R&D Plan of Hubei Province(No.2020BHB004 and No.2020BAB012)the Natural Science Foundation of Hubei Province(No.2020CFB798)。
文摘Research on evacuation simulation and modeling is an important and urgent issue for emergency management.This paper presents an evacuation model based on cellular automata and social force to simulate the evacuation dynamics.Attractive force of target position,repulsive forces of individuals and obstacles,as well as congestion are considered in order to simulate the interaction among evacuees and the changing environment.A visual-guidance-based artificial bee colony algorithm is proposed to optimize the evacuation process.Each evacuee moves toward exits with the guidance of leading bee in his/her visual field.And leading bee is selected according to comprehensive factors including distance from the current individual,the number of obstacles and congestion,which avoids the randomness of roulette mechanism used by basic artificial bee colony algorithm.The experimental results indicate that the proposed model and algorithm can achieve effective performances for indoor evacuation problems with a large number of evacuees and obstacles,which accords with the actual evacuation situation.
