Pedestrian flow through exit:Study focused on evacuation pattern

Experiments are conducted on the evacuation rate of pedestrians through exits with queued evacuation pattern and random evacuation pattern. The experimental results show that the flow rate of pedestrians is larger with the random evacuation pattern than with the queued evacuation pattern. Therefore, the exit width calculated based on the minimum evacuation clear width for every 100 persons, which is on the assumption that the pedestrians pass through the exit in one queue or several queues, is conservative. The number of people crossing the exit simultaneously is greater in the random evacuation experiments than in the queued evacuation experiments, and the time interval between the front row and rear row of people is shortened in large-exit conditions when pedestrians evacuate randomly. The difference between the flow rate with a queued evacuation pattern and the flow rate with a random evacuation pattern is related to the surplus width of the exit, which is greater than the total width of all accommodated people streams. Two dimensionless quantities are defined to explore this relationship. It is found that the difference in flow rate between the two evacuation patterns is stable at a low level when the surplus width of the exit is no more than 45% of the width of a single pedestrian stream. There is a great difference between the flow rate with the queued evacuation pattern and the flow rate with the random evacuation pattern in a scenario with a larger surplus width of the exit. Meanwhile, the pedestrians crowd extraordinarily at the exit in these conditions as well, since the number of pedestrians who want to evacuate through exit simultaneously greatly exceeds the accommodated level. Therefore, the surplus width of exit should be limited especially in the narrow exit condition, and the relationship between the two dimensionless quantities mentioned above could provide the basis to some extent.

A Game-Theoretic Approach to Safe Crowd Evacuation in Emergencies

Obstacle removal in crowd evacuation is critical to safety and the evacuation system efficiency. Recently, manyresearchers proposed game theoreticmodels to avoid and remove obstacles for crowd evacuation. Game theoreticalmodels aim to study and analyze the strategic behaviors of individuals within a crowd and their interactionsduring the evacuation. Game theoretical models have some limitations in the context of crowd evacuation. Thesemodels consider a group of individuals as homogeneous objects with the same goals, involve complex mathematicalformulation, and cannot model real-world scenarios such as panic, environmental information, crowds that movedynamically, etc. The proposed work presents a game theoretic model integrating an agent-based model to removethe obstacles from exits. The proposed model considered the parameters named: (1) obstacle size, length, andwidth, (2) removal time, (3) evacuation time, (4) crowd density, (5) obstacle identification, and (6) route selection.The proposed work conducts various experiments considering different conditions, such as obstacle types, obstacleremoval, and several obstacles. Evaluation results show the proposed model’s effectiveness compared with existingliterature in reducing the overall evacuation time, cell selection, and obstacle removal. The study is potentially usefulfor public safety situations such as emergency evacuations during disasters and calamities.

Study on Evacuation Strategy of Commercial High-Rise Building under Fire Based on FDS and Pathfinder

With the development of economy and society and the growth of population,the high-rise and multi-function of commercial buildings have become an international trend.But it also poses huge fire hazards.Most of the existing studies’research objects are predominantly high-rise residential buildings,without considering the impact of different functional zones(Standard floor,entertainment zone,office zone,equipment room and so on)and personnel distribution of commercial buildings evacuation.And the influence of using elevators to carry evacuees on the refuge floor on personnel evacuation is rarely studied.In this work,the fire scenario of the Yangtze River InternationalConferenceCenter,a high-rise commercial building,is simulated with the Pyrosim programto get the necessary parameters under various fire scenarios and to calculate the available evacuation time TASET.At the same time,according to the complex functional zone of the commercial high-rise building and the distribution of people in different time periods,a reasonable evacuation strategy is developed and simulated by Pathfinder software.The results indicate that unorganized evacuation will lead individuals to take the erroneous evacuation route,resulting in a vast region of congestion;comprehensive consideration of the time staggering and the reasonable distribution of evacuation routes can significantly improve evacuation efficiency,and the TRSET of night and working hours is 36.6%–55.3%and 49.9%–79.6%of unorganized evacuation,respectively.For the night fire,60%of the people use elevator-refuge floor to evacuate is the optimal strategy;for the fire during working hours,half of the people on standard floors use the elevator to evacuate and people on multifunctional floors evacuate in four batches is the best plan.The results of this study can provide viable solutions and a foundation for analyzing the fire evacuation and safety of big commercial high-rise buildings.

Research on Evacuation Path Planning Based on Improved Sparrow Search Algorithm

Reducing casualties and property losses through effective evacuation route planning has been a key focus for researchers in recent years.As part of this effort,an enhanced sparrow search algorithm(MSSA)was proposed.Firstly,the Golden Sine algorithm and a nonlinear weight factor optimization strategy were added in the discoverer position update stage of the SSA algorithm.Secondly,the Cauchy-Gaussian perturbation was applied to the optimal position of the SSA algorithm to improve its ability to jump out of local optima.Finally,the local search mechanism based on the mountain climbing method was incorporated into the local search stage of the SSA algorithm,improving its local search ability.To evaluate the effectiveness of the proposed algorithm,the Whale Algorithm,Gray Wolf Algorithm,Improved Gray Wolf Algorithm,Sparrow Search Algorithm,and MSSA Algorithm were employed to solve various test functions.The accuracy and convergence speed of each algorithm were then compared and analyzed.The results indicate that the MSSA algorithm has superior solving ability and stability compared to other algorithms.To further validate the enhanced algorithm’s capabilities for path planning,evacuation experiments were conducted using different maps featuring various obstacle types.Additionally,a multi-exit evacuation scenario was constructed according to the actual building environment of a teaching building.Both the sparrow search algorithm and MSSA algorithm were employed in the simulation experiment for multiexit evacuation path planning.The findings demonstrate that the MSSA algorithm outperforms the comparison algorithm,showcasing its greater advantages and higher application potential.

The Many Facets of History:A Study on the Accounts of the Dunkirk Evacuation

This paper adopts a New Historicism approach to examine the shaping of the history of the Dunkirk evacuation through an analysis of Winston Churchill’s historic speech We Shall Fight on the Beaches,Ian McEwan’s novel Atonement,and Christopher Nolan’s film Dunkirk.The research reveals that by uncovering and representing the neglected stories of marginalized groups in Atonement and Dunkirk,new evidentiary threads both enrich and contest the History embodied in Churchill’s speech.Consequently,these alternative accounts both challenge and complement the prevailing historical discourse.

The Impact of Sea Level Rise on Roadway Design and Evacuation Routes in Delaware

As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.

Integrating AnyLogic Simulation in Emergency Evacuation Management for Enhanced Security

This study introduces an innovative approach by integrating AnyLogic simulation into emergency evacuation strategies to enhance security protocols.The research focuses on leveraging advanced computational models to simulate and optimize evacuation scenarios in various settings,including public venues,residential areas,and urban environments.By integrating real-world data and behavioral models,the simulation accurately represents human movements,decision-making processes,and traffic flow dynamics during evacuation scenarios.The study evaluates the effectiveness of various evacuation strategies,including route planning,crowd behavior,and emergency response coordination,using a scenario-driven approach within the AnyLogic simulation environment.Furthermore,this research contributes to the establishment of optimized emergency response protocols by systematically evaluating and refining evacuation plans.The research frameworks mentioned in the research imply the efficient use of the AnyLogic simulation model to be used in different sectors and fields to enhance the strategies for saving lives and implementing an efficient evacuation management system.

Pedestrian evacuation simulation in multi-exit case:An emotion and group dual-driven method

This paper analyzes the characteristics of emotion state and group behavior in the evacuation process.During the emergency evacuation,emotion state and group behavior are interacting with each other,and indivisible.The emotion spread model with the effect of group behavior,and the leader-follower model with the effect of emotion state are proposed.On this basis,exit choice strategies with the effect of emotion state and group behavior are proposed.Fusing emotion spread model,leader-follower model,and exit choice strategies into a cellular automata(CA)-based pedestrian simulation model,we simulate the evacuation process in a multi-exit case.Simulation results indicate that panic emotion and group behavior are two negative influence factors for pedestrian evacuation.Compared with panic emotion or group behavior only,pedestrian evacuation efficiency with the effects of both is lower.

Effect of a static pedestrian as an exit obstacle on evacuation

Building exit as a bottleneck structure is the last and the most congested stage in building evacuation.It is well known that obstacles at the exit affect the evacuation process,but few researchers pay attention to the effect of stationary pedestrians(the elderly with slow speed,the injured,and the static evacuation guide)as obstacles at the exit on the evacuation process.This paper explores the influence of the presence of a stationary pedestrian as an obstacle at the exit on the evacuation from experiments and simulations.We use a software,Pathfinder,based on the agent-based model to study the effect of ratios of exit width(D)to distance(d)between the static pedestrian and the exit,the asymmetric structure by shifting the static pedestrian upward,and types of obstacles on evacuation.Results show that the evacuation time of scenes with a static pedestrian is longer than that of scenes with an obstacle due to the unexpected hindering effect of the static pedestrian.Different ratios of D/d have different effects on evacuation efficiency.Among the five D/d ratios in this paper,the evacuation efficiency is the largest when d is equal to 0.75D,and the existence of the static pedestrian has a positive impact on evacuation in this condition.The influence of the asymmetric structure of the static pedestrian on evacuation efficiency is affected by D/d.This study can provide a theoretical basis for crowd management and evacuation plan near the exit of complex buildings and facilities.

Model considering panic emotion and personality traits for crowd evacuation

Panic is a common emotion when pedestrians are in danger during the actual evacuation, which can affect pedestrians a lot and may lead to fatalities as people are crushed or trampled. However, the systematic studies and quantitative analysis of evacuation panic, such as panic behaviors, panic evolution, and the stress responses of pedestrians with different personality traits to panic emotion are still rare. Here, combined with the theories of OCEAN(openness, conscientiousness,extroversion, agreeableness, neuroticism) model and SIS(susceptible, infected, susceptible) model, an extended cellular automata model is established by the floor field method in order to investigate the dynamics of panic emotion in the crowd and dynamics of pedestrians affected by emotion. In the model, pedestrians are divided into stable pedestrians and sensitive pedestrians according to their different personality traits in response to emotion, and their emotional state can be normal or panic. Besides, emotion contagion, emotion decay, and the influence of emotion on pedestrian movement decision-making are also considered. The simulation results show that evacuation efficiency will be reduced, for panic pedestrians may act maladaptive behaviors, thereby making the crowd more chaotic. The results further suggest that improving pedestrian psychological ability and raising the standard of management can effectively increase evacuation efficiency. And it is necessary to reduce the panic level of group as soon as possible at the beginning of evacuation. We hope this research could provide a new method to analyze crowd evacuation in panic situations.

Intelligent fire information system based on 3D GIS

Background This work aims to build a comprehensive and effective fire emergency management system based on the Internet of Things(IoT)and achieve an actual intelligent fire rescue.A smart fire protection information system was designed based on the IoT.A detailed analysis was conducted on the problem of rescue vehicle scheduling and the evacuation of trapped persons in the process of fire rescue.Methods The intelligent fire visualization platform based on the three-dimensional(3D)Geographic Information Science(GIS)covers project overview,equipment status,equipment classification,equipment alarm information,alarm classification,alarm statistics,equipment account information,and other modules.The live video accessed through the visual interface can clearly identify the stage of the fire,which facilitates the arrangement of rescue equipment and personnel.The vehicle scheduling model in the system primarily used two objective functions to solve the Pareto Non-Dominated Solution Set Optimization:emergency rescue time and the number of vehicles.In addition,an evacuation path optimization method based on the Improved Ant Colony(IAC)algorithm was designed to realize the dynamic optimization of building fire evacuation paths.Results The experimental results indicate that all the values of detection signals were significantly larger in the smoldering fire scene at t=17s than the initial value.In addition,the probability of smoldering fire and the probability of open fire were relatively large according to the probability function of the corresponding fire situation,demonstrating that this model could detect fire.Conclusions The IAC algorithm reported here avoided the passages near the fire and spreading areas as much as possible and took the safety of the trapped persons as the premise when planning the evacuation route.Therefore,the IoT-based fire information system has important value for ensuring fire safety and carrying out emergency rescue and is worthy of popularization and application.

Pathfinder-Based Simulation and Optimization of Evacuation of Large Commercial Complexes

Large commercial complexes are large in scale, complex in function, and located in densely populated areas that are prone to casualties due to unfavorable evacuation. To comprehend the safety evacuation of large commercial complex buildings in China, investigate the safety evacuation problems encountered during the evacuation process and the evacuation optimization design strategy, the paper uses Pathfinder to build a simulation model based on literature research and study to simulate the evacuation of personnel in a large commercial complex in Dalian and explore its problems during the evacuation process. The results show that the type of personnel has an effect on the large commercial complex’s evacuation simulation results;the total number of evacuees is non-linearly correlated with the time change curve;some staircases take a long time to evacuate and have a low utilization rate. To improve evacuation efficiency, optimization suggestions for safety exits, evacuation stairs, and evacuation channels are made based on the results.

Sanitary Evacuations at the Maternity Unit of the Social Hygiene Institute (IHS) in Dakar in 2020

Objective: Determine the frequency of evacuations, specify the epidemiological and clinical characteristics of the evacuees, evaluate the data of the evacuation, the management and the maternal-fetal prognosis. Methods: Prospective and descriptive retrospective study concerning obstetrical evacuations received at the maternity ward of the Hospital of the Institute of Social Hygiene in Dakar between January 1 and December 31, 2020, i.e. a period of 12 months. Results: During the study period, we collected 1156 evacuees out of a total of 3507 patients treated in the Service, i.e. a frequency of 33%. The average age of the patients was 27.07 years with extremes of 14 and 46 years. Patients aged between 20 and 29 were the most represented (51.73%). The average parity was 1.6 with extremes of 0 and 10 pares. The nulliparous (46.37%) were the majority. The majority of evacuated patients (99.6%) resided in the Dakar region, including 58% in the suburbs and 42% in the city center. The patients received had performed an average of 3 prenatal consultations with extremes ranging from 0 to 9 CPN. They most often came from health centers (55.05%) or hospitals (29.09%). The reasons for evacuations were dominated by dystocia (21.54%) followed by premature rupture of membranes (17.21%) and premature deliveries (16.35%). On admission, only 176 patients (15.2%) had an evacuation sheet. Patients transited on average through two health structures (extremes ranging from 0 to 7 structures) before reaching the reception structure. The evacuation was most often done with a private vehicle on the patient’s own means (91.96%). The outcome of the evacuees was most often vaginal delivery or hospitalization (72.79%). The majority of patients (99.4%) had evolved favorably but we deplore one maternal death (0.09%) linked to a late puerperal infection. We recorded 74 perinatal deaths and 1041 live births, i.e. a stillbirth rate of 71.1‰ live births. The causes of death were dominated by prematurity (24.7%). Conclusion: Obstetrical evacuations are frequent in our practice but they should be better organized to improve the maternal-fetal prognosis.

An extended social force model on unidirectional flow considering psychological and behavioral impacts of hazard source

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.

Effect of early stepwise cardiopulmonary rehabilitation on function and quality of life in sepsis patients

BACKGROUND Sepsis,as a non-limiting host infection disease,can be accompanied by serious complications such as organ failure,which seriously threatens patient quality of life.AIM To investigate the effect of early stepwise cardiopulmonary rehabilitation on cardiopulmonary function and quality of life in patients evacuated from mechanical ventilation with sepsis.METHODS A total of 80 patients with sepsis who were hospitalized in our hospital from January 2021 to January 2022 were selected and divided into the observation group(n=40)and the control group(n=40)according to the random number table method.The observation group was treated with early stepwise cardiopulmonary rehabilitation,and the control group was treated with a conventional treatment regimen.Cardiac function indexes(central venous pressure,cardiac troponin I,B-type brain natriuretic peptide),lung function indicators(diaphragmatic mobility,changes in central venous oxygen saturation,oxygenation index),and quality of life(Quality of Life Evaluation Scale)were compared between the two groups after treatment.RESULTS After treatment,the central venous pressure,diaphragm mobility,central venous oxygen saturation,oxygenation index,and Quality of Life Evaluation Scale scores in the observation group were higher than those in the control group,and the differences were statistically significant(P<0.05).The observation group was less than that of the control group for other parameters,and the differences were statistically significant(P<0.05).CONCLUSION Early stepwise cardiopulmonary rehabilitation can effectively enhance cardiac and pulmonary function and improve the quality of life in patients evacuated from mechanical ventilation with sepsis.

Logit-based exit choice model of evacuation in rooms with internal obstacles and multiple exits

A logit-based discrete choice model is proposed to study the exit choice behaviour of evacuees in rooms with internal obstacles and multiple exits. Several factors influencing the exit choice behaviour, including the information obtained by evacuees, the tendency of following others, the visibility and familiarity of exits and the physical conditions of nearby exits, are considered. Evacuees are allowed to re-select their target exits for minimizing the perceived disutility during evacuation process. Numerical results from applying the model to cellular automata simulation of evacuation are presented and the effects of some model parameters on evacuation time are investigated.

Location-allocation modeling for emergency evacuation planning with GIS and remote sensing:A case study of Northeast Bangladesh

This work developed models to identify optimal spatial distribution of emergency evacuation centers(EECs)such as schools,colleges,hospitals,and fire stations to improve flood emergency planning in the Sylhet region of northeastern Bangladesh.The use of location-allocation models(LAMs)for evacuation in regard to flood victims is essential to minimize disaster risk.In the first step,flood susceptibility maps were developed using machine learning models(MLMs),including:Levenberg-Marquardt back propagation(LM-BP)neural network and decision trees(DT)and multi-criteria decision making(MCDM)method.Performance of the MLMs and MCDM techniques were assessed considering the area under the receiver operating characteristic(AUROC)curve.Mathematical approaches in a geographic information system(GIS)for four well-known LAM problems affecting emergency rescue time are proposed:maximal covering location problem(MCLP),the maximize attendance(MA),p-median problem(PMP),and the location set covering problem(LSCP).The results showed that existing EECs were not optimally distributed,and that some areas were not adequately served by EECs(i.e.,not all demand points could be reached within a 60-min travel time).We concluded that the proposed models can be used to improve planning of the distribution of EECs,and that application of the models could contribute to reducing human casualties,property losses,and improve emergency operation.

Guided Crowd Evacuation:Approaches and Challenges

Evacuation leaders and/or equipment provide route and exit information for people and guide them to the expected destinations, which could make crowd evacuation more efficient in case of emergency. The purpose of this paper is to provide an overview of recent advances in guided crowd evacuation. Different guided crowd evacuation approaches are classified according to guidance approaches and technologies. A comprehensive analysis and comparison of crowd evacuation with static signage, dynamic signage, trained leader, mobile devices, mobile robot and wireless sensor networks are presented based on a single guidance mode perspective. In addition, the different evacuation guidance systems that use high-tech means such as advanced intelligent monitoring techniques, AI techniques, computer technology and intelligent inducing algorithms are reviewed from a system’s perspective. Future researches in the area of crowd evacuation are also discussed.

Stair evacuation simulation based on cellular automata considering evacuees' walk preferences

As a physical model, the cellular automata （CA） model is widely used in many areas, such as stair evacuation. However, existing CA models do not consider evacuees＇ walk preferences nor psychological status, and the structure of the basic model is unapplicable for the stair structure. This paper is to improve the stair evacuation simulation by addressing these issues, and a new cellular automata model is established. Several evacuees＇ walk preference and how evacuee＇s psychology influences their behaviors are introduced into this model. Evacuees＇ speeds will be influenced by these features. To validate this simulation, two fire drills held in two high-rise buildings are video-recorded. It is found that the simulation results are similar to the fire drill results. The structure of this model is simple, and it is easy to further develop and utilize in different buildings with various kinds of occupants.

Discrete element crowd model for pedestrian evacuation through an exit

A series of accidents caused by crowds within the last decades evoked a lot of scientific interest in modeling the movement of pedestrian crowds. Based on the discrete element method, a granular dynamic model, in which the human body is simplified as a self-driven sphere, is proposed to simulate the characteristics of crowd flow through an exit. In this model, the repulsive force among people is considered to have an anisotropic feature, and the physical contact force due to body deformation is quantified by the Hertz contact model. The movement of the human body is simulated by applying the second Newton＇s law. The crowd flow through an exit at different desired velocities is studied and simulation results indicated that crowd flow exhibits three distinct states, i.e., smooth state, transition state and phase separation state. In the simulation, the clogging phenomenon occurs more easily when the desired velocity is high and the exit may as a result be totally blocked at a desired velocity of 1.6 m/s or above, leading to faster-to-frozen effect.