Simulating the Dynamic Escape Process in Large Public Places
紧兵逃生疏散英语作文
紧兵逃生疏散英语作文Emergency Evacuation and Escape。
In the event of an emergency, it is crucial to have a well-planned and organized evacuation and escape strategy. Whether it is a fire, earthquake, or any other disaster, being prepared can save lives. This document will provide guidelines and recommendations for an effective emergency evacuation and escape plan.1. Understand the Emergency Procedures。
Before an emergency occurs, it is essential to familiarize yourself with the emergency procedures specific to your location. Whether it is your workplace, school, or residential building, make sure you know the evacuation routes, assembly points, and emergency contacts. This information should be readily available and clearly communicated to everyone.2. Create an Evacuation Plan。
Developing an evacuation plan is crucial for any organization or household. Identify multiple escape routes from each area and ensure they are well-lit, unobstructed, and easily accessible. Assign responsibilities to individuals to assist vulnerable individuals, such as the elderly or disabled, during the evacuation process.3. Conduct Regular Drills。
CFD 计算对计算网格有特殊的要求
CFD 计算对计算网格有特殊的要求，一是考虑到近壁粘性效应采用较密的贴体网格，二是网格的疏密程度与流场参数的变化梯度大体一致。
对于面网格，可以设置平行于给定边的边界层网格，可以指定第二层与第一层的间距比，及总的层数。
对于体网格，也可以设置垂直于壁面方向的边界层，从而可以划分出高质量的贴体网格。
而其它通用的CAE 前处理器主要是根据结构强度分析的需要而设计的，在结构分析中不存在边界层问题，因而采用这种工具生成的网格难以满足CFD 计算要求，而Gambit 软件解决了这个特殊要求。
如果先在一条边上画密网格再在之上画边界层，边界层与网格能很好的对应起来如果直接在一条边上画边界层，则边界层横向之间的距离很宽怎么设置边界层横向之间的距离，即不用先画网格也能画出横向距离很密的边界层来？在划分边界层网格之前，用粘性网格间距计算器，计算出想要的y+值对应的第一层网格高度；第一层高度出来之后，关于网格的纵横向网格间距之比，也就是边界层第一层网格高度与横向间距之比，大概在1/sqrt(Re)，最为适宜；先在你要划边界层网格的边上划分线网格，然后再划分边界层。
gambit本人也用了一段时间，六面体网格四面体网格我都画过，但是最头疼的还是三维边界层网格的生成。
用gambit自带的边界层网格生成功能画出来的边界层网格经常达不到好的效果，或者对于复杂的外形根本就无法生成边界层网格。
为此我就采用手动设置边界层，但是比较费时间，效果还一般。
不知道大家是不是也遇到相似的问题，或者有更好的方法，请指点一下，先谢谢了！22 什么叫松弛因子？松弛因子对计算结果有什么样的影响？它对计算的收敛情况又有什么样的影响？1、亚松驰（Under Relaxation）：所谓亚松驰就是将本层次计算结果与上一层次结果的差值作适当缩减，以避免由于差值过大而引起非线性迭代过程的发散。
用通用变量来写出时，为松驰因子（Relaxati on Factors）。
地铁站疏散Modeling the pedestrian’s movement and simulating evacuation
Modeling the pedestrian’s movement and simulating evacuation dynamics onstairsYunchao Qu,Ziyou Gao ⇑,Yao Xiao,Xingang LiSchool of Traffic and Transportation,Beijing Jiaotong University,Beijing 100044,Chinaa r t i c l e i n f o Article history:Received 23December 2013Received in revised form 15May 2014Accepted 22May 2014Available online 26June 2014Keywords:Pedestrian flowStaircase movement Dynamic characteristics Social force modela b s t r a c tThis paper presents an enhanced social force model to describe the pedestrian’s movement and evacua-tion dynamics on pared with original models that described the pedestrian’s planar motion,our model introduces some mechanisms of the staircase movement,such as the influence of staircase geometry,the restriction of the step size and the optimal velocity selection.The body shape of each pedestrian is regarded as a set of three circles to precisely quantify the movement.In addition,the rotation dynamics are included into the model to describe the congestion effect.The improved model can obtain individual velocity under different staircase geometries and the flow characteristics of the evacuation dynamics.Some empirical data and a series of observations captured in two subway stations in Beijing are applied to study the characteristics and further validate the model.The results show that our model performs well consistent with the observed data.At last,simulations are implemented to find the solutions of estimating the evacuation time and evaluating the capacity of stair.Ó2014Elsevier Ltd.All rights reserved.1.IntroductionStairs are widely used in all kinds of buildings,especially in large scale public places,i.e.,subway stations,shopping malls and office buildings.Walking on stairs is very common and important in our daily lives,and scientific design and effective utilization of stairs are urgently needed for designers and managers (Peacock et al.,2009).In emergency,such as power failure,fire,earthquake or other hazards,the elevators may be out of commission,and the stairs become the primary escape routes.If there are too many peo-ple crowded on stairs,they will pack closer together or even lead to some dangerous situations (Shields and Boyce,2009).Knowing the flow characteristics and predicting the egress time are the key points to grasp the evacuation dynamics and make emergency response plans on stairs (Graat et al.,1999;Oven and Cakici,2009).The characteristics of pedestrian staircase movement are deter-mined by organizational,constructional and behavioral factors:the organizational factors,i.e.,preparation for emergencies;the constructional factors,i.e.,the staircase geometry including riser height,tread depth and step width (Graat et al.,1999;Fujiyama and Tyler,2010);the behavioral factors,i.e.,responses and move-ment characteristics of pedestrians (Yang et al.,2012;Ma et al.,2012).The study of the staircase movement is an interdisciplinaryfield with different focuses,such as biomechanics,physics,physiol-ogy,phycology,computer science,safety science (i.e.,Hankin and Wright,1958;Fruin,1971;Predtechenskii and Milinskii,1978;Templer,1992;Batty,1997;Helbing et al.,2000;Hase and Yamazaki,2002;Nelson et al.,2002;Hoskin,2004;Pauls,2005;Trew,2005;Casburn et al.,2007;Hostikka et al.,2007;Galea et al.,2008;Kretz et al.,2008;Seer,2008;Xu and Song,2009;Fujiyama and Tyler,2010;Galea et al.,2010;Hoskins,2011;Halsey et al.,2012;Yang et al.,2012;Peacock et al.,2012;Burghardt et al.,2013).To make quantitative analyses and detailed descriptions of staircase movement,many researches have carried out a lot of sur-veys,experiments and evacuation drills on stairs,and have collected large amounts of experimental and observational data of staircase movement (please see Table 1for details).In these studies,the flow characteristics of staircase movement are described in individual level and collective level.Pedestrian flow in low densities reflects the characteristics in the individual level,and walking speed is influ-enced by physiological feature and body function,such as gender,age,height,weight,heart rate,rate of oxygen consumption and rate of energy expenditure (Irvine et al.,1990;Teh and Aziz,2002;Halsey et al.,2012).It is also influenced by stairway geometries and movement direction.Pedestrian flow in high densities reflects the characteristics in the collective level.The collective behaviors include pedestrians’self-organized behaviors and optimal route choice behaviors (i.e.,Helbing et al.,2000,2005;Moussaid et al.,2011).The researches of pedestrian flow in the collective level focus on three aspects,(1)evaluating evacuation time,(2)reproducing/10.1016/j.ssci.2014.05.0160925-7535/Ó2014Elsevier Ltd.All rights reserved.⇑Corresponding author.Tel.:+861051688193.E-mail address:zygao@ (Z.Gao).fundamental diagram,and(3)describingflow characteristics,i.e., inflow,outflow,capacity.Staircase movement is a complicated three-dimensional move-ment,and modeling the movement is a quite challenging work. Nowadays,researches have integrated behavioral and construc-tional factors,and have established many models to analyze the flow characteristics and simulate evacuation processes in both sin-gle-story and multi-story buildings(Table1).In our work,we mainly focus on the case of single-story staircases.These models are classified into two categories:macroscopic model and micro-scopic model(Zheng et al.,2009).The macroscopic models regard the crowd as a single entity,and focus onfitting the expression of fundamental diagram.Linear,piecewise linear and non-linear functions(i.e.,Fruin,1971;Warren,1984;Tanaboriboon et al., 1986;Weidmann,1993;Lam and Cheung,2000;Proulx,2002; Peacock et al.,2012;Hoskins and Milke,2012)have been applied to describe relationship between velocity and density under differ-ent stair geometries.Compared with macroscopic models,the microscopic models are able to precisely describe the individual behavior,qualitatively explain the evacuation dynamics and reproduce some self-orga-nized phenomena(Helbing et al.,2000).These microscopic models are spatial-discrete models(cellular automation model,i.e., Kirchner et al.,2004;Huang and Guo,2008;Schadschneider and Seyfried,2009)and spatial-continuous models(social force model, i.e.,Helbing et al.,2000).These models have been applied to reveal two-dimensional planar movement,but few of them have described the three-dimensional staircase movement(Song et al., 2006;Pelechano and Malkawi,2008;Xu and Song,2009;Ma et al.,2012).In addition,the spatial-discrete models are some restricted to describe the staircase movement,such as grid size,fatigue factor,route selection,and uneven use of stairs (Pelechano and Malkawi,2008).Although the spatial-continuous models are advantageous to solve most of the aforementioned problems,these models are quite rare.Social force model(Helbing and Molnar,1995)is a well-known spatial-continuous model in thefield of pedestrianflow.The model can reproduce several self-organized phenomena,such as lane forming,arching queue,shock waves and clogging effects (Helbing et al.,2005,2007).Moussaid et al.(2011)have proposed a heuristics-based model to replace the social force with a heuris-tics intelligent optimum function.Based on the heuristic social force model,this paper introduced some special rules and estab-lished an enhanced model to describe the mechanisms of pedes-trian movement and evacuation dynamics on stairs.Firstly,the body shape of each pedestrian is regarded as a set of three circles (Thompson and Marchant,1995).Compared with traditional sin-gle-circle shape(i.e.,Helbing et al.,2000),the three-circle shape precisely represents the projection of human body and describes the rotation movement when two pedestrians collide with others. Secondly,pedestrians usually walk more carefully on stairs than on planar,so two‘safety rules’are proposed to describe staircase movement behavior.Thefirst rule is that a pedestrian wants to walk upstairs/downstairs with integral steps at a time,and the step-size is restricted by the staircase geometry,such as tread depth,riser height and step width.The second rule is that a pedes-trian tends to walk along the sides,i.e.,holding handrails,propping up against walls.Thirdly,the relaxation time is extended to a var-iable in our model.The relaxation time is defined that a pedestrian tends to correspondingly adapt his/her actual velocity to desired velocity with a certain characteristic time s(i.e.,Helbing et al., 2000;Moussaid et al.,2011).The relaxation time is mostlyTable1The state-of-the-art of staircase movement.Author(s)Year Method Model EvacuationprocessWalking speed NoteDynamics FD Geometry Direction Hankin and Wright1958Data analysis–s d s d–Fruin1971Data analysis–s d s s Planning methodPredtechenskii and Milinskii1978Data analysis Planning model s d s s Planning methodTanaboriboon et al.1986Macro Linear function s d s s Fundamental diagram Weidmann1993Macro Non-linear function s d d d–Frantzich1996Data analysis–s d d d–Graat et al.1999Data analysis–s d s s Capacity estimation Lam and Cheung2000Macro BPR function s d d d Fundamental diagram,capacityestimation Proulx et al.2002Data analysis Non-linear function d d s s SFPENelson and Mowrer2002Data analysis Non-linear function d d s s SFPEHoskin2004Softwaresimulation Coordinate-basedmodeld d d d Simulex32Pauls2005Data analysis–d s s s–Hostikka et al.2007Data analysis–d d s s–Kretz et al.2008Data analysis–s d d d Pedestrian movement on long stairs Seer et al.2008Data analysis–d d s s Flow characteristicsPelechano and Malkawi2008SoftwaresimulationGrid based model d s s s Literature review(STEPS,EXODUS)Galea et al.2008Software Evacuation model d s s s Merging behavior at interactions Xu and Song2009Micro Multi-grid model d s s s Flow characteristics,such as in and outflow Fujiyama and Tyler2010Macro Linear function s s d d Individual walking speed Galea et al.2010Data analysis–d d s s Evacuation softwareHoskins2011Macro Linear function d d d d Fundamental diagramYang et al.2012Data analysis–d d d s Evacuation drillLei et al.2012Softwaresimulation–d s s s Software(FDS,EVAC) Hoskins and Milke2012Data analysis–s d s s NISTPeacock2012Data analysis–d d d s NIST,different measurement methods Ma et al.2012Data analysis CA d s s s SimulationBurghardt et al.2013Data analysis–s d s s Fundamental diagramd Represents the factor is included and s represents the factor is not included.190Y.Qu et al./Safety Science70(2014)189–201assumed to be a constant in previous models,but it is not inade-quate to describe the staircase movement.As mentioned before, the individual walking speed on stairs is influenced by many fac-tors,such as staircase size,movement direction,and physical char-acteristics.For example,pedestrians spend more energy on walking upstairs than downstairs,spend more time on walking steep stairs than gentle stairs.Pedestrians with different age, weight or gender may require different relaxation times when walking on different stairs.Considering the influence factors,the relaxation time is formulated as a linear function of individual weight,moving height,and the slope of stairs.The linear function is similar to the model(Fujiyama and Tyler,2010),and some parameters are introduced to distinguish the upstairs and down-stairs movement.In this paper,some empirical data in literatures are collected and new observations from subway stations are conducted.In Sec-tion2,the characteristics of pedestrianflow on the stairs are dis-cussed.Based on the data and analysis,the constructional and behavioral factors are introduced to the social force model to pre-cisely describe the individual staircase moment in Section3.To validate the model,a series of simulations are implemented,and the simulation results are compared with the observational and empirical data in Section4.Simulations are implemented to ana-lyze theflow characteristics and the evacuation process in subway stations in Section5.Finally,the conclusions and the further work are given in Section6.2.Data collection andflow characteristics on stairs2.1.Empirical data of pedestrian speedOccupant speed is a very important element of pedestrianflow, and pedestrian speed on stairs is mainly affected by the slope of stairway,depth of tread,height of riser,and presence and location of handrails(Gwynne et al.,2009).Graat et al.(1999)had found that speed and capacity on stairs were higher with a normal (30°)slope than a steep(38°)slope.Kretz et al.(2008)had found that some pedestrian accelerate when walking upward a short stairway,and the mean upward walking speed on the short stair-way was found to be roughly twice as large as the one on the long stairway.Fujiyama and Tyler(2010)had proposed a model to pre-dict the walking speed based on the weight,leg power and the gra-dient of the stairs.The evacuation process of a large number of people is another major concern for researchers and designers. During the evacuation,the evacuation process something likes a queuing system that contains the processes of congestion forming, propagation and dissipation(Ma et al.,2012).Besides,the stair width and capacity will affect the route/exit choice behaviors and the evacuation efficiency(Lei et al.,2012).Researches have obtained many observational and experimen-tal data of staircase movement.However,this study here is not intended to be an exhaustive review of all researches.The refer-ences which mentioned both staircase geometry and individual speed are taken into consideration.Ten instances of staircase are included in our paper,and more detailed data can be found in the literatures(i.e.,Weidmann,1993;Frantzich,1996;Fujiyama and Tyler,2010;Hoskins,2011;Peacock et al.,2012).From Table2, it is found that walking speeds listed in the studies are different. This may be caused by natural variation of individual capability, staircase geometry,density of crowd and other factors.Besides, different measurement methods of calculating travel distances and areas on stairs may lead to different results(Hoskins and Milke,2012).Fujiyama and Tyler(2010)have made some experi-ments and found that average upstairs and downstairs speeds were0.58m/s and0.67m/s,respectively.Peacock et al.(2012) have mentioned that average downstairs speeds in their study of 0.48±0.16m/s were observed to be quite similar to the range of literature values.Kretz et al.(2008)have pointed that the density also affected the individual speed.Ma et al.(2012)have made a series of evacuation drills to obtain the average downstairs speed of0.547m/s.Even though different researchers have come up with different values for movement on stairs,most give a maximum for density of4.5–5.5pedestrians/m2,a maximum for speed of0.7–1.2m/s,and maximum for capacity of0.8–1.5pedestrians/(m s).2.2.Observations in subway stationsSomefire drill evacuations of office buildings have been imple-mented by National Institute of Standards and Technology(NIST), and the collected staircase movement data have included a range of stair geometries and occupant densities(Peacock et al.,2012; Hoskins and Milke,2012).However,in those studies,the local speed and the density were inaccurately estimated according to the collected data.It was because the cameras did not fully record the whole of staircase movement.In the drills,cameras were set every twofloors to record an overhead view of occupant move-ment.The view of each camera only covered the main landing area plus tread depth area for about4–6steps of one story.Between every two cameras,there was a mid-landing,where pedestrian movement was a planar movement,but not a staircase movement. It was impossible to dissociate the planar movement on mid-land-ing from the video,so the calculations of the travel distance and travel time of staircase movement were inaccurate.To precisely investigate the pedestrian movement characteristics on stairs,we improved the method of video recording,and conducted observa-tions of whole staircase movement in two stations of Beijing sub-way Line1.The two stations are Sihui East Station(ascendingflow)and Xidan Station(descendingflow).The Sihui East Station is a termi-nal station and all the passengers should get off the train and go to the transfer hall;therefore,the pedestrianflow on the observed stair is an ascendingflow.The Xidan Station is also a transferTable2Individual horizontal speeds in ten instances of staircases with different geometries.ID Riser height(mm)Tread depth(mm)Gradient(°)Horizontal speed(m/s)Source Note#H120021043.60.361("),0.509(;)a Frantzich(1996)Narrow stair #H215030519.00.427("),0.601(;)Lam(2000)MTR #H316327131.00.417("),0.569(;)Lam(2000)KCR #H419027035.10.423(")Kretz(2008)Long stairs #H515029027.30.538("),0.581(;)Fujiyama(2010)Elder people #H615726730.50.590("),0.721(;)Fujiyama(2010)Young people #H718623838.00.488(;)a Peacock(2012)11-Floors #H819125436.90.440(;)a Peacock(2012)18-Floors #H915028028.20.547(;)Ma(2012)SWFC #H1014028026.50.53(;)Yang(2012)Stair No.2#a The speeds were converted to horizontal speeds.Y.Qu et al./Safety Science70(2014)189–201191station and the passengers can get on or off the train by the stair, and there is an escalator on one side of the stair to relieve the coun-tering passengerflows.Therefore,the pedestrianflow is a descend-ingflow.The schematic diagram of the observation stations is shown in Fig.1,and the information of the stairs is shown in Table3.A HD camera was set on the transfer hall to record the trail of each passenger.The observations in the subway stations were made during the afternoon rush hours of weekend(17:30–18:30,Sunday)on May 12,2013.In our observations,383pedestrians(216males,167 females)were collected at the selected staircases in Xidan Station, and221pedestrians(129males,92females)were collected in Sihui East Station.Most of the pedestrians were young and mid-dle-aged people,and their ages mostly ranged from25to55years old.The proportion of children and elderly was very low.In our observations,most of the pedestrians carried light bags and walked in a normal speed on staircases.Because the camera was not right above on the observed region, the passengers were sometimes overlapped in the video.Each pedestrian was recorded by individual characteristics,such as gen-der,age,body size,hair,shirt and pants.Then,the pedestrians were recognized by their features,entering and leaving time.The speed of each pedestrian was calculated by the travel time(leaving time minus entering time)dividing the travel distance on the stairs.The video recordings were processed semi-manually,and the dynamic evacuation characteristics,such as average density,speed andflow,were analyzed.Take Xidan station for example,the evac-uation dynamic characteristics and a snapshot were illustrated in Fig.2a–c).It was found that the curve of time-varying density was divided into several segments,and each segment represented a stream of pedestrians entering and leaving the stairs.During the observation,some measures,such asflow restriction and guidance, had been adopted to avoid crowdedness,so the density of pedestri-ans on stairs was in a normal(low)level.There were eight local maximum points exceeding1.0pedestrians/m2,and the maximal density was about1.6(1/m2).Velocity showed an opposite trend of density.The velocityfluc-tuated between0.4m/s and1.0m/s,and the average velocity was about0.57m/s.The volatility of individual velocities might be caused by different individual capability and desired velocity.In a low density,the pedestrians who walked fast would overtake front pedestrians who walked slowly and blocked them.When the density became larger,the pedestrians began to slow down and follow with others,and then queues might form on stairs.In Fig.2d),the acquainted or familiar people might walk abreast, which is regarded as‘subgroup behavior’(Yang et al.,2012).If they walked slower than the surrounding people,they would form a dynamic bottleneck.Additionally,lane-forming phenomenon was also found.In Fig.3a),the distributions of the speeds during the observa-tions followed normal distributions,which were similar with the reference(Peacock et al.,2012).The average velocities of walking upstairs and downstairs were0.55m/s and0.63m/s,respectively. Affected by gravity,going upstairs was slower than going down-stairs.By gathering the observed data of unidirectionalflow,the relationships between the velocity and the density were shown in Fig.3(b).The velocity decreased as the density increased.It should be noted that,in a low density,the velocity of going upstairs was a little higher than downstairs.It was because some of the pedestrians were hurried out of station and ran more than one steps at one time.3.Modeling the pedestrian’s movement on stairs3.1.Body shapesIn the existing models,the projection of a pedestrian’s body shape is usually regarded as a square(i.e.,Kirchner et al.,2004), a rectangular(i.e.,Song et al.,2006;Weng et al.,2007),a circle (i.e.,Helbing et al.,2000),an ellipse(i.e.,Chraibi et al.,2010)or a set of three circles(Thompson and Marchant,1995).In these geo-metrical shapes,the three-circle shape has some geometrical and computational advantages on modeling the staircase movement. First of all,the three-circle shape is a better alternative to describe the pedestrian’s body shape.It is because the occupied space of one pedestrian is restricted by the stairs,and the shoulder width of the pedestrian is larger than lateral width(Xu and Song,2009).In addi-tion,a pedestrian walks with a relative slow speed on stairs,and his/her space requirement keeps almost constant.Secondly,in social force model,the distance of closest approach of two pedes-trians is a key parameter when calculating the self-driven force, the repulsive force and the contact force.The closet distance between two single-circle or three-circle shapes can be easily cal-culated(Thompson and Marchant,1995);however,the calculation of the closest distance of two ellipses is surprisingly difficult (Zheng and Palffy-Muhoray,2007).For the convenience of calcula-tion,the three-circle shape is a better alternative than ellipse shape.Therefore,the three-circle shape is chosen to describe pedestrian’s body shape,and the schematic diagram is shown in Fig.4.3.2.Modified social force modelThe well-known social force model(Helbing and Molnar,1995; Helbing et al.,2000)is a microscopic force-based model that can reproduce several self-organized phenomena,such as lane form-ing,arching queue,shock waves and clogging effects(Helbing et al.,2005,2007;Moussaid et al.,2011).The model describes pedestrians’movement behavior by introducing the self-driven force~f Di,the contact force with pedestrians~f Cijand walls(obstacles) ~f Ciw.The self-driven force can be calculated by Eq.(1),and the total force~f exerted on pedestrian i can be formulated as Eq.(2).192Y.Qu et al./Safety Science70(2014)189–201~f D i ¼m ~m desiÀ~m isð1Þ~f i ¼~f D i þXj~f C ij þXw~f C iwð2ÞMoussaid et al.(2011)have proposed a heuristics-based modelto replace the social force with a heuristics intelligent optimum function,which can be regarded as a so-called collision prediction process.The model can overcome some difficulties in the original versions.Based on the model,we use the three-circle shape,intro-duce some special rules and establish an enhanced model todescribe the staircase movement.In our model,the modifications are concentrated on the calculations of optimal direction selection,self-driven force and contact force.3.2.1.Selecting optimal direction In Eq.(1),the desired velocity ~m des i can be obtained by the mag-nitude m des i multiplies by the direction ~e des iof desired velocity.The calculation of ~e desi is called ‘optimal direction selection’,which isTable 3Detailed step sizes.ID StationStep number Width (mm)Depth (mm)Height (mm)Gradient (°)Flow direction#O1Xidan Station 16240030014025.0Descending flow #O2Sihui East Station15190033015726.1Ascending flow(b) Change of pedestrian density with time inthe observation of staircase #O1(c) Change of pedestrian speed with time inthe observation of staircase #O1(d) A snapshot of the observations in staircase #O2(a) Change of pedestrian flow with time inthe observation of staircase #O1 Fig.2.Processed data and a snapshot.Y.Qu et al./Safety Science 70(2014)189–201193an important component of the model(Moussaid et al.,2011).In our work,the body shape is extended to three-circle shape,and the calculation becomes a little complex.To make a clear state-ment,some notation and definitions are given as follow:for pedes-trian i,the large circle’s radius is r i1,the small circle’s radius is r i2, the mass is M i,the maximum velocity is v0i,the location is~l i,the velocity is~m i and the desired destination is~D i.Assume that pedestrian i moves at the velocity v0i along the direction of direction a,and will contact with pedestrian j after D t time.The i0and j0represent the locations of i and j at time t+D t.Then,fðaÞ¼v0iÁD t is the distance to thefirst collision with other pedestrian or obstacle in the direction a.If no collision is expected to occur,f(a)is set to a default value d max,which repre-sents the‘maximum horizon distance’of pedestrian i.The calcula-tion of furthest distance without collision f(a)can be improved as follows:l ixm ðtþD tÞ¼l ixmðtÞþv ix D t;l iy mðtþD tÞ¼l iy mðtÞþv iy D tðm;n2f1;2;3gÞl jxn ðtþD tÞ¼l jxnðtÞþv jx D t;l jy nðtþD tÞ¼l jy nðtÞþv jy D tðl ixm ðtþD tÞÀl jxnðtþD tÞÞ2þðl iymðtþD tÞÀl jynðtþD tÞÞ2¼ðr imþr jnÞ2ð3ÞPut thefirst two items into the third item,we can get a qua-dratic equation with moving time D t.Given the locations and velocities of pedestrians i and j,the D t can be easily solved.Then, the value fða i m j nÞand dðaÞcan be calculated asfða i m j nÞ¼min f v i Deltat;d max g;fðaÞ¼min f fða i m j nÞg;aüargmin f dðaÞg dðaÞ¼d2maxþfðaÞÀ2d max fðaÞcosða0ÀaÞð4ÞThe optimal velocity direction~e¼ðcos aÃ;sin aÃÞ;here,aüargmin f dðaÞg is the optimal direction.Fig.5illustrates the calculation.3.2.2.Self-driven forces and contact forcesThe pedestrian’s staircase movement is a three-dimensional motion,which contains horizontal and vertical motion.Pedestrian should change his/her center of gravity to ascend or descend the stairs,which are shown in Fig.6(a)and(b).The complicated move-ment includes the pedestrian’s physiological activity and energy transformation.In our work,we mainly focus on the pedestrians’horizontal optimal choice and crowding behaviors,so the vertical motion is approximately regarded as a linear motion,which is shown in Fig.6(c).In horizontal motion,pedestrians not only over-take front people with slower speeds but also have to notice the steps and prevent themselves from falling down from stairs.To mathematically depict horizontal movement,some assumptions and rules are introduced to simplify the movement,which is illus-trated in Fig.6(d).Thefirst assumption is that a pedestrian wants to move forward within n steps(n is integer).And the pedestrian’s desired destina-tion of next footstep is the center of the forward step.For example, in Fig.6d),pedestrian often moves forward with integer steps,i.e., one step(point A)or two steps(point B).When he/she moves for-ward with non-integer step,i.e.,2.5steps(point C),he/she will move to the edge of the step,and may feel unstable,unsafe or even fall down from the stairs.Therefore,point C is not considered in our model.The pedestrian’s horizontal footstep length is defined as d h¼nDcos b,and is restricted by the tread depths D and riser heights H of the step.Here,b is the included angle between the optimal direction aÃand the x-coordinate.If the pedestrian is obstructed by other pedestrians or obstacles,he/she will slow down and avoid collision,and the footstep length does not exceed the maximal dis-tance fðaÃÞ(Eq.(4))in the optimal direction aÃ.Finally,the footstep length is expressed as:d h¼minnDcos b;fðaÃÞ&'ð5ÞAccording to the model(Moussaid et al.,2011),a pedestrian maintains a distance from thefirst obstacle in the chosen walking direction that ensures a time to collision of at least a relaxation time s.In other words,desired velocity of pedestrian i is formu-lated as v des i¼d h s.Additionally,pedestrian’s speed is assumed to not exceed a maximum velocity v max.Then,the horizontal maxi-mum velocity is v max cos h,and the angle h represents the slope of the stair tan h¼HÀÁ.The horizontal desired velocity v des i can be formulated as Eq.(6):v desi¼mind hs;vmaxcos hð6Þ(a) Probability distribution(b) Fundamental diagramFig.3.Speed and fundamental diagram of theobservations.194Y.Qu et al./Safety Science70(2014)189–201。
仿真边界参数-概述说明以及解释
仿真边界参数-概述说明以及解释1.引言1.1 概述概述部分的内容可以简要介绍关于仿真边界参数的背景和重要性。
可以从以下几个方面进行描述：首先，指出仿真边界参数在各种仿真模型中起到至关重要的作用。
仿真边界参数是指在进行仿真实验时所设定的边界条件，包括物体的初始状态、环境的外界影响以及仿真系统与外部系统的交互规则等。
这些参数的设定直接关系到仿真模型的准确性和可靠性，对于研究结果的可信度具有重要影响。
其次，强调仿真边界参数的准确性和合理性对于仿真模型的有效性至关重要。
只有在合理设置仿真边界参数的情况下，仿真模型才能够准确地模拟真实世界中的现象和行为。
因此，在进行仿真实验前，需要对待仿真对象的特性、环境背景以及规定的边界条件进行充分的研究和了解，并据此设置合适的仿真边界参数。
此外，指出仿真边界参数在不同领域的应用多样且广泛。
仿真技术被广泛应用于汽车工程、航空航天、生物医学等众多领域。
在这些领域中，仿真边界参数的准确性对于模拟系统的行为和性能至关重要。
例如，在汽车工程中，通过准确设置边界参数，可以模拟不同道路条件对车辆操控性能的影响，指导车辆设计和优化。
因此，研究和探索仿真边界参数在不同领域的应用，对于推动相关领域的发展具有重要意义。
最后，总结指出本文将重点研究仿真边界参数的设定原则和优化方法，以提高仿真模型的准确性和可靠性。
通过对这些方面的深入研究和讨论，有助于提升仿真模型的性能，并为相关领域的发展提供有力的支持和指导。
通过以上的概述，可以引起读者对于仿真边界参数的关注，为接下来的具体内容做好铺垫。
1.2文章结构文章结构部分的内容可以如下编写：1.2 文章结构本文按照以下结构进行组织和论述：第一部分为引言部分，分为三个子部分。
在1.1 概述部分，将介绍仿真边界参数的背景和重要性，以及目前存在的问题和挑战。
在1.2 文章结构部分，阐明了整篇文章的组织结构和每个部分的内容。
在1.3 目的部分，明确了本文的研究目的和预期结果。
疏散演练英语作文
The Importance of Evacuation Drills: A CaseStudyIn today's world, the importance of being prepared for emergencies cannot be overstated. One such preparedness measure is the regular conduct of evacuation drills, which are designed to simulate real-life scenarios and help individuals and organizations alike understand their evacuation procedures. This article explores thesignificance of evacuation drills, their benefits, and a case study that highlights their effectiveness.The primary purpose of evacuation drills is tofamiliarize people with the evacuation plan and proceduresin case of an emergency. These drills simulate real-life scenarios, such as fires, earthquakes, or other disasters, and require participants to follow a pre-determined routeto a designated safe area. By participating in these drills, individuals and organizations can identify potential issues and bottlenecks in their evacuation plans, allowing them to make necessary adjustments and improve their readiness.The benefits of evacuation drills are numerous. Firstly, they improve the overall safety of individuals andorganizations by ensuring that everyone knows what to do in case of an emergency. Secondly, they help to identify and correct any flaws or issues in the evacuation plan, ensuring its effectiveness. Furthermore, evacuation drills can also be used to train employees on safety procedures, enhancing their knowledge and skills.To further illustrate the importance of evacuation drills, let's consider a case study from a large corporate office building. This building, which housed hundreds of employees, conducted regular evacuation drills as part of its safety protocol. One day, a small fire broke out in one of the floors, triggering the building's alarm system. Thanks to the regular drills, employees knew exactly what to do. They followed the evacuation plan, used the designated escape routes, and safely evacuated the building within minutes. The fire was quickly extinguished by the building's fire suppression system, and no one was injured. This incident highlighted the effectiveness of evacuation drills in ensuring the safety of employees.In conclusion, evacuation drills are crucial for enhancing the safety of individuals and organizations. Bysimulating real-life scenarios and identifying potential issues, they allow for the identification and correction of flaws in evacuation plans. Regular conduct of these drills also ensures that everyone is familiar with the evacuation procedures, improving their readiness in case of an emergency. The case study of the corporate office building further illustrates the importance of evacuation drills in ensuring the safety of employees. Therefore, it is imperative for organizations to prioritize the conduct of regular evacuation drills and ensure their effective implementation.**疏散演练的重要性：案例分析**在当今世界，为紧急情况做好准备的重要性不言而喻。
基于粒子群算法(PSO)的人员疏散动力学模型
基于粒子群算法(PSO)的人员疏散动力学模型郑瑶辰;陈建桥;魏俊红;郭细伟【摘要】基于粒子群算法思想,建立紧急情况下公共场馆人员疏散的动力学模型.该模型考虑人员之间的相互作用,依据人员实时局部密度的变化改变个体的最大速度以及保有区域尺寸,具有时空非均匀的特点.定义个体冲量以及受伤冲量阈值,考虑人员受伤对疏散过程的影响,同时还比较了多出口疏散与单出口疏散的特点和效率.算例结果表明,疏散结果与元胞自动机模型相似,理想化更新流程的结果小于其他疏散模型的结果.%By applying the evolutionary algorithm of Particle Swarm Optimization (PSO), a new dynamic model for pedestrian evacuation is developed. In this newly proposed model, with the increase of local density of a particle, both the maximal velocity and the particle size decrease, implying that the model possesses space-time non-uniformity features. At the same time, we introduced two threshold values for damage and injury and investigated the influences of these parameters. Numerical results showed similar characteristics with those based on Cellular Automata (CA).【期刊名称】《武汉理工大学学报（交通科学与工程版）》【年(卷),期】2012(036)002【总页数】5页(P283-287)【关键词】人员疏散;粒子群算法;局部密度;理想化更新;受伤【作者】郑瑶辰;陈建桥;魏俊红;郭细伟【作者单位】华中科技大学力学系武汉430074;工程结构分析与安全评定湖北省重点实验室武汉430074;;【正文语种】中文【中图分类】X913.4;TP391.9目前，人员疏散模型的建模方法大致可分为2种：一种是宏观的方法，即把人群视为连续流动介质，利用Navier－Stokes控制方程来描述人群的运动，但此方法忽略了疏散人群中个体的作用和个体间的差异；另一种是微观的方法，如社会力模型［1］和元胞自动机模型［2－4］.格子气模型（LGA）是元胞自动机的一种特殊形式.在格子气模型中，每个行人在栅格中被视为自主粒子.LGA可以再现拥挤的人群在疏散过程中的某些特征［5］.Izquierdo等提出在模拟人员疏散过程的时候使用粒子群算法（particle swarm optimization，PSO）模型.PSO模型属于微观建模方法，将行人抽象为粒子，并利用自身最优以及群体最优的信息，不断向出口靠近并完成疏散［6］.本文对PSO方法用于人员疏散进行拓展，考虑局部密度对个体最大速度和保有区域的影响，建立时空非均匀人员疏散动力学数值模型，提出理想化流程思想以及人员受伤理论.其成果可以为大型公共建筑的防灾设计、安全疏散性能评估、日常管理和应急管理提供依据.1 PSO方法描述粒子群优化算法是一种进化型算法，原始的想法是模拟一群鸟试图到达一个未知目的地（如食物位置）的社会行为［7］.利用粒子群算法来模拟人群疏散的问题中，目的地就是疏散区域的某个出口，“粒子”理解为公共空间里每个移动的人.模拟过程中首先由计算机生成等同于人群数目的粒子，并随机分布在目标区域，然后粒子根据自己个体和社会行为规则，随时间进行位置更新（进化），朝向目的地移动.在标准的PSO算法中，粒子的位置和速度的更新方程如下［8］.式中：Xi为人群的位置；Vi为人员移动的速度；Pi为第i个粒子的最好位置；Pg 为群体的最好位值；c1和c2为加速因子，分别表示粒子朝向自己之前到达的最佳位置和全局最佳位置的加速权重；rand（）为0到1之间的随机数；ω为惯性因子.式（2）表明，粒子速度更新由3部分组成：粒子i的速度惯性，个体最好位置的吸引，群体最好位置的吸引.2 人员疏散非均匀PSO模型2.1 人员疏散PSO模型的特点在工程优化问题中，PSO算法中的每个粒子代表一个候补解，多个候补解可以是重叠的.在人员疏散过程中，粒子是疏散区域中待疏散的个体，每个人都有自己的保有区域，其他人不能进入.因此在人员疏散模拟过程中，必须考虑人与人之间出现的位置冲突.目前常用的CA模型中，疏散区域被划分为离散区域，每个人在每个时间步中移动的距离相同，即速度矢量的大小相同，方向也被离散，这和现实中的人员移动有较大差别.在PSO模型中，疏散区域不用划分为格子，运动空间是连续的，同时，速度具有连续性，个体速度在最大速度的限制范围内依据式（2）进行更新.2.2 考虑局部密度影响的粒子位置更新规则式（2）中惯性因子ω按下式确定［9］式中：k为速度更新迭代次数.随着k的增加，ω从1减小到0.5.加速因子取为c1＝3，c2＝2.粒子的适应度函数选为粒子到离自身最近的出口坐标的距离，由此计算出粒子的最好位置Pi.在人员疏散问题中，最优解是已知的，即为疏散区域的出口，所以作为候补解的每个个体最终都到达疏散区域的出口.因此，将Pg定义为出口坐标.考虑到人群移动的实际情况，粒子的速度有一个上限：Vi≤Vmax.在人员疏散过程中，人员移动的最大速度和其周围人群的密度是相关的.定义局部密度ρ为目标粒子周围2m范围内其他粒子的个数，假定粒子最大速度与局部密度ρ的关系为每个粒子用直径为0.5m的圆来模拟，定义为个体的保有区域，当局部密度ρ较大时，保有区域可以发生变化，粒子的保有区域D与局部密度ρ的关系为粒子之间位置冲突的解决方案见图1，在某一时间步，粒子A通过式（1）和式（2）更新，位置移动到A″，若粒子A和粒子B发生位置冲突，则改变粒子A速度矢量的大小，使得粒子A与粒子B保有区域边界正好相切，粒子A的位置从A″修正到A′.图1 冲突解决方案示意图2.3 理想化PSO模型的计算流程利用PSO模拟人群疏散时，粒子位置更新是按照粒子编号的顺序进行的.这与实际疏散过程中的同步更新（疏散过程不受粒子编号的影响）有很大差别.本文提出理想化PSO更新规则，即：认为距离出口最近的粒子的移动是一定成立的，不需要通过冲突解决方案来修正速度.在每个时间步，按照粒子的适应度函数的大小给粒子重新编号，这样就会产生一个队列，使粒子按照队列顺序更新.需要指出的是由以上规则得到的疏散时间是所有其他规则相应结果的下限.3 基于PSO人员疏散的过程分析3.1 人员疏散的特征定义疏散区域为边长16m的正方形平面区域，出口宽度为2m，疏散人数为100人，时间步长为0.5s，下面采用PSO方法模拟疏散过程.图2中，a），b），c）3个图分别为此次模拟中1.5，4和14.5s时各个粒子所在位置.由图2a）中可见，在出口附近的粒子能快速的从疏散区域撤离，而其他的粒子也能找到自己的方向；在图2b）所示时刻，粒子开始聚集在出口附近，一部分粒子受到一定程度的挤压；图2c）所示时刻，粒子大量聚集在出口附近，大部分粒子受到严重程度的挤压.经过较多时间，所有粒子最终能全部从疏散区域撤离.无特别说明，以下结果均为基于理想化流程的次模拟结果的平均值.图3为疏散结果与疏散总人数的关系曲线.其中均匀模型是指个体的最大速度及保有区域不变化，非均匀模型是指按式（4）和式（5）变化的情形.图2 人员疏散模拟过程（横、纵坐标为无量纲基本单位）疏散结果有2个指标，分别是疏散总时间与平均疏散时间.疏散总时间表示的是最后一个粒子离开疏散区域的时间，而平均疏散时间指的是粒子离开疏散区域所需时间的均值.从图3可以看到，无论是非均匀模型还是均匀模型，和CA模型一样，疏散时间与疏散总人数大致呈线性关系，平均疏散时间约为疏散总时间的一半.比较非均匀模型和均匀模型，前者的疏散时间小于后者，这是因为随着局部密度的增大，保有区域减小，使得粒子有更多的活动空间.从数值上来看，CA模型得到的疏散总时间要大于PSO模型得到的疏散总时间，这是因为PSO算法使用了理想化流程.图3 疏散结果－疏散总人数关系曲线基于非均匀模型疏散总人数为100人时的疏散时间频度如图4所示.由图4可见，在前面较长的时间里面，每个时间段内从疏散区域离开的粒子数目基本相同.疏散开始时，靠近出口附近的粒子先从疏散区域逃离，而后面的粒子按照队列逐个从出口逃离，离出口越近的粒子越容易逃离.这是将疏散过程理想化之后的结果，也是平均疏散时间约为疏散总时间一半的原因.图4 疏散总人数为100人的疏散时间频度3.2 理想化流程对疏散结果的影响在初始化的时候固定位置、速度、适应度函数等粒子的信息，分别分2种情况进行多次模拟，一种是理想化模拟，另一种则是非理想化模拟，即粒子的编号顺序随机.定义疏散区域为边长16m的正方形平面区域，出口宽度为2m，时间步长为0.5s，将多次模拟的结果取平均值，见图5.图5 理想化与非理想化的比较由图5可以看出，理想化模拟得到的疏散结果，无论是疏散总时间还是平均疏散时间都小于非理想化模拟得到的结果.在同等条件下，粒子按适应度函数从小到大的顺序排序会对整个疏散过程产生利于疏散成功的效果.每一次非理想化模拟的疏散结果差别很大，而理想化模拟得到的疏散结果基本相同.这也表明，在更新过程中，将粒子按照适应度函数从小到大排序是最利于疏散成功的，所得到的疏散结果代表疏散时间的下限.3.3 出口位置对疏散过程的影响增加疏散区域的出口，会有效减少疏散时间.以下研究出口位置对疏散过程的影响.模拟下面3种情况：a）2个宽为2m的出口，位于疏散区域的同一边上，相距4m；b）2个宽为2m的出口，分别在疏散区域的2个邻边上；c）2个宽为2m的出口，分别在疏散区域的2个对边上.对于多个出口，Pg也对应有多个.在每个时间步，粒子分别对每个出口计算适应度函数，根据最小适应度函数来选择Pg，以此更新粒子的速度.图6 出口位置对疏散时间的影响4 考虑人员损伤受伤的疏散模型在紧急疏散的情况下，人往往处于非理性状态，其运动行为容易对他人造成伤害.本文认为，在某个微小的时间段内，A个体对B个体作用的冲量大于某冲量阈值，会导致B的损伤或者受伤.在粒子初始化时，对粒子分别赋予范围为40～90kg的质量，并引进动量与冲量的概念.定义2个参数：损伤冲量Ia和受伤冲量Ib，假定粒子的最大速度与粒子受到的冲量I之间有如下关系：当冲量介于Ia和Ib之间，认为粒子的运动能力有所下降，若粒子最大速度等于0，则认为该人员受伤，无法移动.如前所述，解决位置冲突时，是改变速度步长的大小.对于受伤的情形，如粒子B被粒子A冲击导致受伤，无法移动，会发生粒子A始终在粒子B旁边也无法移动的情况.此时直接让粒子A的速度矢量的方向旋转π／2，使粒子A能够绕过粒子B继续前进.图7是基于损伤受伤模型的结果.模拟过程中，由于开始时刻出口对人员的吸引较大，粒子的速度较大，不久后便出现损伤受伤人员，见图7a）；由于在出口附近拥堵，易于出现损伤人员，并一起堵塞于出口附近，见图7b）；经过较长时间，堵塞现象得到解决，未受伤人员最终全部疏散成功，受伤人员则留在疏散区域内. 图7 损伤受伤模型疏散示意图（横、纵坐标为无量纲基本单位）在受伤模拟中，损伤冲量代表的是导致人员身体损伤的冲量阈值，超过这个值，个体能力发生改变（式（6）），而受伤冲量代表的是在疏散过程人所能承受的冲量的最大值.不同损伤冲量下的人员受伤情况如表1所列，从表中发现当损伤冲量越大，平均受伤人数就越少，若增大受伤冲量而保持损伤冲量不变，那么平均受伤人数同样减少.表1 受伤冲量为100N·s时受伤人数与损伤冲量的关系损伤冲量／（N·s－1）平均受伤人数70 22.5 80 11.1 90 6.25 结束语本文建立了基于PSO算法的非均匀人群疏散动力学模型.模型考虑人员局部密度对粒子最大速度和保有区域的影响，以及粒子移动过程中位置的冲突等因素.与常用的CA模型类似，模拟结－果中的疏散时间与疏散总人数的关系接近为线性关系.本文模型还引进动量与冲量的概念，定义了粒子的损伤冲量和受伤冲量阈值，考虑了疏散过程中人员受伤的影响.基于PSO的疏散模型考虑了人员移动速度的连续性以及人员之间的相互作用，因此模拟结果能更好的反映实际疏散情况.参考文献［1］Helbing D，Farkas I，Vicsek T.Simulating dynamical features of escape panic［J］.Nature，2000，407（6803）：487－490.［2］Zhao D L，Yang L Z，LI J.Occupants′behavior of going with the crowd based on cellular automata occupant evacuation model［J］.Physica A （Statistical Mechanics and its Applications），2008，387（14）：3 708－3 718.［3］Varas A，Cornejo M D，Mainemer D，et al.Cellular automaton model for evacuation process with obstacles［J］.Physica A（Statistical Mechanics and its Applications），2007，382（2）：631－642.［4］陈晨，陈建桥.基于细胞自动机方法的车行运动模型及信号灯控制策略研究［J］.武汉理工大学学报：交通科学与工程版，2010，34（2）：258－261. ［5］Song W G，Xu X，Wang B H，et al.Simulation of evacuation processes using a multi－grid model for pedestrian dynamics［J］.Physica A （Statistical Mechanics and its Applications），2006，363（2）：492－500.［6］Izquierdo J，Montalvo I，Pérez R，et al.Forecasting pedestrian evacuation times by using Swarm intelligence［J］.Physica A （StatisticalMechanics and its Applications），2009，388（7）：1 213－1 220. ［7］Kennedy J，Eberhart R C.Particle swarm optimization［C］∥IEEE International Conference on Neural Networks，Perth，WA，1995（4）：1 942－1 948.［8］Shi Y，Eberhart R C.A modified particle swarm optimizer［C］∥IEEE International Conference on Evolutionary Computation Proceedings，Anchorage，AK，1998：69－73.［9］Jin Y X，Cheng H Z，Yan J Y，et al.New discrete method for particle swarm optimization and its application in transmission network expansion planning［J］.Electric Power Systems Research，2007，77（3－4）：227－233.。
小学三年级英语课：学习消防宣传的英文口号
小学三年级英语课：学习消防宣传的英文口号一级标题：Introduction二级标题：The Importance of Teaching Fire Safety in English ClassesFire safety is a crucial topic that needs to be taught to students from an early age. As technology continues to evolve, fire hazards are becoming increasingly complex, necessitating the adoption of fire safety practices. Therefore, it is imperative for elementary school education, such as the third grade English class, to incorporate lessons on fire safety and raise awareness among young learners. In this article, we will explore the significance of teaching fire safety in the form of English slogans or mottos.一级标题：Understanding Fire Safety: Basic Concepts for Young Learners二级标题：Fire Prevention: Playful Slogans for Young MindsTo engage young learners and make fire safety education enjoyable, using playful slogans in English classes proves effective. These catchy phrases not only improve their vocabulary but also enable them to remember important fire safety tips effortlessly. Here are some suitable examples:1. "Don't play with matches; stay safe from fires!"2. "Firefighters save lives – let's learn how!"3. "Escape plans are cool – always have one at home!"4. "Safety first! Fire drills keep us prepared!"It is essential to explain these slogans thoroughly so that children understand the meaning behind each phrase. Educators can present real-life scenarios where these slogans apply.一级标题：Calling for Action: Empowering Students through English Slogans二级标题：Encouraging Proactive Measures: Individual ResponsibilityTeaching fire safety slogans in English classes not only instills knowledge but also empowers students to take action and assume individual responsibility in preventing fires. By emphasizing the importance of personal accountability, students become proactive in building safe habits and encouraging others to do the same.Educators can facilitate discussions around practical actions students can take at school and home:1. Creating a checklist for checking smoke alarms monthly2. Educating family members on fire safety practices learned in class3. Simulating escape plans at home and ensuring every household member knows the drillBy employing English slogans, students will be inspired to adopt these practices actively.一级标题：Collaborative Learning: Teamwork and Safety二级标题：Promoting Unity through Fire Safety SlogansFire safety education is an opportunity for students to cultivate teamwork and unity within their communities. By learning together and practicing fire prevention measures as a team, children establish strong bonds while promoting safety amongst peers.To foster collaborative learning, educators can:1. Organize group activities based on fire safety themes2. Encourage discussions to exchange ideas on creating new fire safety slogans3. Promote the incorporation of fire safety slogans in school campaigns or eventsThis approach not only enriches their English language skills but also strengthens their sense of belonging and collective responsibility toward fire safety.一级标题：ConclusionIn conclusion, teaching fire safety through English slogans in third-grade classrooms serves as an effective method to engage young learners while equipping them with essential knowledge and practical skills. By using playful yet informative phrases, students connect with the subject matter more actively, encouraging them to take personal responsibility in preventing fires. Furthermore, this approach fosters collaboration among students while promoting a safer environment for all. Teaching fire safety in English classes empowers children and ensures they are well-prepared to handle potential fire incidents both at home and beyond.。
学校火灾疏散逃生演练公开课心得体会英语作文
学校火灾疏散逃生演练公开课心得体会英语作文全文共3篇示例，供读者参考篇1A Lesson in Safety: Reflections on Our School's Fire DrillAs students, we often take the safety measures in place at our school for granted. The fire alarms, exit signs, and evacuation procedures are just part of the backdrop against which we attend classes, socialize with friends, and go about our daily routines. However, a recent public lesson on fire safety and evacuation drills has made me realize just how crucial these protocols are for our well-being.The lesson began with a sobering statistic: according to the National Fire Protection Association, there were an estimated 3,700 fires in schools across the country last year, resulting in millions of dollars in property damage and, tragically, several injuries and even loss of life. These numbers were a stark reminder that the threat of fire is very real, and that complacency can have devastating consequences.Our instructor, a seasoned firefighter with over two decades of experience, then proceeded to walk us through the variouscomponents of our school's fire safety plan. We learned about the different types of fire alarms and their distinct sounds, the location of fire extinguishers and how to operate them correctly, and the importance of keeping hallways and exits clear of obstructions.But the highlight of the lesson was undoubtedly the fire drill simulation. As the alarm blared through the speakers, we were instructed to calmly gather our belongings and proceed to the nearest exit in an orderly fashion. Outside, we assembled at our designated meeting point, where teachers took roll call to ensure that everyone had evacuated safely.It was during this exercise that the true significance of fire drills became apparent to me. In the chaos and confusion that would undoubtedly ensue during a real emergency, having a well-rehearsed plan and clear lines of communication could mean the difference between life and death.One aspect of the drill that particularly struck me was the role of the designated "floor wardens" – students who had been trained to assist in the evacuation process. As we filed out of the building, these wardens were stationed at strategic points, guiding us towards the exits and ensuring that no one was left behind. Their calm demeanor and decisive actions were atestament to the importance of proper training and preparedness.Another valuable lesson I took away from the experience was the need for constant vigilance and attention to detail. Our instructor emphasized that fire safety is an ongoing process, and that even the smallest oversights – a propped-open fire door, a blocked exit, or a malfunctioning alarm – could have catastrophic consequences.In the aftermath of the drill, I found myself looking at our school's fire safety measures with a newfound appreciation. The exit signs, once mere points of reference, now took on a deeper significance, reminding me of the carefully choreographed escape routes that had been meticulously planned. The fire extinguishers, once innocuous objects lining the walls, became potential lifesavers in the event of an emergency.But perhaps the most profound impact of the lesson was the sense of community and shared responsibility it fostered. As we gathered outside, united in our commitment to safety, I realized that each of us played a vital role in ensuring the well-being of our school community. From the custodians who diligently maintained the fire suppression systems to the administratorswho oversaw the implementation of the safety protocols, every member of our school had a part to play in keeping us secure.In the weeks and months that followed, I found myself paying closer attention to the fire safety measures around me –not just at school, but in other public spaces as well. I became more conscious of identifying exit routes and potential hazards, and I felt empowered to speak up if I noticed any potential safety concerns.Ultimately, the public lesson on fire drills and evacuation procedures was a powerful reminder of the importance of preparedness and vigilance in the face of potential emergencies. It instilled in me a deeper sense of respect for the dedicated individuals who work tirelessly to ensure our safety, and a renewed commitment to playing my part in fostering a secure and resilient community.As students, it is easy to take the measures in place for our protection for granted. But this experience has taught me that true safety is a collaborative effort, one that requires constant vigilance, open communication, and a shared sense of responsibility. By embracing these lessons and remaining proactive in our approach to fire safety, we can create anenvironment where learning can flourish without the looming shadow of danger.篇2A Lesson in Survival: Reflections on the Fire Evacuation DrillAs students, we often take the safety measures in our school for granted. The fire alarms, exit signs, and emergency protocols seem like mere formalities, never to be truly put into practice. However, the recent fire evacuation drill conducted at our school served as a powerful wake-up call, reminding us of the importance of preparedness and the fragility of our daily routines.The day began like any other, with the familiar sights and sounds of the bustling hallways and classrooms. Little did we know that our complacency was about to be shattered by the piercing wail of the fire alarm. At first, there was a moment of confusion, a brief hesitation as we tried to discern whether it was a drill or a genuine emergency. However, the urgency in our teachers' voices left no room for doubt – this was the real deal.In an orderly fashion, we filed out of our classrooms and followed the well-marked exit routes, our hearts pounding with a mixture of adrenaline and apprehension. The hallways echoedwith the sound of hundreds of footsteps, and the air was thick with the tension of the unknown. As we made our way towards the designated assembly area, I couldn't help but wonder how we would fare in an actual fire.Once outside, we were greeted by the sight of our classmates and teachers, all gathered together in a show of unity and resilience. It was then that the true purpose of the drill became apparent – a public lesson in survival, a chance for us to witness firsthand the importance of swift and coordinated action in the face of an emergency.The school's administration, in collaboration with local fire officials, took the stage and began to outline the intricate details of the evacuation plan. Their words were a sobering reminder of the potential consequences of inaction or panic in such situations. They emphasized the importance of remaining calm, following instructions, and prioritizing the safety of ourselves and those around us.As the presentation unfolded, we were treated to a visual demonstration of proper fire evacuation techniques. The sight of firefighters donning their gear and simulating rescue operations was both awe-inspiring and humbling. It drove home the reality that, in the event of a real emergency, our lives could very welldepend on the expertise and bravery of these dedicated professionals.One aspect of the drill that struck me profoundly was the emphasis on teamwork and communication. We learned that effective evacuation requires not only individual preparedness but also a collective effort. Each of us has a role to play, whether it's assisting those with mobility challenges, clearing paths, or relaying vital information. In that moment, we were no longer just individuals but a cohesive unit, united in our pursuit of safety.The drill also highlighted the importance of remaining vigilant and proactive in our daily lives. We were reminded that fire hazards can lurk in the most unexpected places – a carelessly discarded cigarette butt, an overloaded electrical outlet, or a forgotten candle. It is our responsibility to remain aware of our surroundings and take preventative measures to minimize the risk of fire.As the event drew to a close, I couldn't help but feel a sense of gratitude and newfound respect for the dedication of our school's faculty and the local emergency services. Their commitment to ensuring our safety was palpable, and their efforts had undoubtedly made a lasting impression on all of us.In the days and weeks that followed, the lessons learned during the fire evacuation drill remained etched in my mind. I found myself paying closer attention to exit signs, mentally mapping out escape routes, and taking note of potential hazards. It was as if a veil had been lifted, and I could now see the world through a lens of heightened awareness and preparedness.Moreover, the experience fostered a sense of community and solidarity among my fellow students. We had faced a simulated crisis together, and in doing so, we had forged an unspoken bond – a shared understanding of the importance of looking out for one another in times of need.As I reflect on that day, I am reminded of the fragility of life and the importance of being prepared for the unexpected. The fire evacuation drill was not merely a mundane exercise but a powerful lesson in survival, a reminder that complacency and ignorance can have dire consequences. It was a wake-up call that has forever altered my perspective, instilling in me a deeper appreciation for the safety measures in place and a renewed commitment to vigilance.In a world where emergencies can strike without warning, the knowledge and skills imparted during the fire evacuation drill have become invaluable tools in our arsenal. They haveempowered us to face potential crises with confidence and resilience, armed with the understanding that preparedness and teamwork are the keys to overcoming even the most daunting challenges.As students, we have been entrusted with the responsibility of not only acquiring academic knowledge but also cultivating a sense of preparedness and community. The fire evacuation drill has taught us that true safety extends beyond the confines of the classroom and into the realm of collective action and awareness.In the end, the lasting impact of this experience lies not only in the practical lessons learned but also in the profound realization that we are all interconnected, bound by a shared commitment to safeguarding one another's well-being. It is a lesson that transcends the walls of our school and extends into the broader tapestry of society, reminding us that preparedness is not merely a necessity but a moral obligation – one that we must embrace wholeheartedly to ensure a safer and more resilient future for all.篇3A Life-Saving Lesson: Reflections on Our School's Fire Evacuation DrillAs students, we often take safety measures for granted, assuming that emergencies are events that happen to others, not us. However, the recent fire evacuation drill conducted at our school served as a powerful reminder of the importance of preparedness and vigilance. This open class, designed to educate us on the proper procedures to follow in the event of a fire, left an indelible mark on my mind and instilled in me a newfound sense of responsibility towards my own well-being and that of my peers.The day began like any other, with the familiar routine of classes and breaks. Little did we know that our complacency was about to be shattered by the shrill sound of the fire alarm echoing through the hallways. Initially, there was a mix of confusion and apprehension, as we wondered whether this was a real emergency or just another drill. However, the calm and authoritative voice of our principal over the intercom system quickly dispelled any doubts, instructing us to initiate the evacuation procedures we had been taught.As we filed out of our classrooms in an orderly fashion, I couldn't help but feel a sense of trepidation. Despite having participated in numerous drills throughout my academic career, the gravity of the situation hit me like never before. Suddenly,the mundane act of following the designated evacuation routes took on a new level of significance, as I realized that in a real fire, every second could mean the difference between life and death.The sight of my fellow students moving swiftly yet calmly towards the assembly point was both reassuring and inspiring. It was a testament to the effectiveness of our preparedness training and the cooperation of our school community. As we gathered in the designated area, I couldn't help but feel a sense of pride in our collective ability to respond to such a potential crisis with poise and discipline.Once the all-clear signal was given, we were ushered back into the auditorium for the open class portion of the drill. It was here that the true value of this exercise became apparent. A team of professionals, including firefighters and safety experts, took the stage to provide us with invaluable insights into fire safety and the importance of adhering to proper evacuation protocols.Their presentations were both informative and eye-opening. We learned about the different types of fires and how they spread, the various fire suppression systems in place within our school, and the crucial role that each of us plays in ensuring a safe and orderly evacuation. The firefighters, in particular, shared harrowing stories of real-life incidents they had encountered,driving home the gravity of the situation and the potential consequences of complacency or panic.One aspect that resonated deeply with me was the emphasis placed on maintaining clear and unobstructed evacuation routes. As they pointed out, a simple act of leaving a backpack or a chair in a hallway could potentially impede the flow of traffic during an emergency, putting countless lives at risk. It was a sobering reminder of how even the smallest actions can have far-reaching consequences in such situations.Another valuable lesson I took away from the open class was the importance of remaining calm and following instructions from authorized personnel. In the chaos of an emergency, it can be easy to succumb to fear and act impulsively, which could lead to disastrous outcomes. The experts stressed the need to stay focused, listen carefully, and trust in the training and expertise of those leading the evacuation efforts.As the open class drew to a close, I found myself filled with a renewed sense of appreciation for the tireless efforts of our school administration, faculty, and emergency responders in ensuring our safety. The dedication and professionalism they exhibited in organizing and executing this drill was trulycommendable, and it reinforced my belief in the strength of our community.Moreover, the experience left me with a heightened awareness of my personal responsibility in contributing to a safe and secure learning environment. It is not enough to simply know the evacuation procedures; we must actively practice and internalize them, remaining vigilant and prepared for any potential threats that may arise.In the aftermath of the open class, I found myself reflecting on the broader implications of fire safety and emergency preparedness. It became clear to me that the lessons learned transcended the confines of our school and extended into our daily lives. Whether at home, at work, or in public spaces, the ability to recognize potential hazards and respond appropriately in an emergency situation could mean the difference between life and death.As I look back on this experience, I am filled with gratitude for the opportunity to participate in such a meaningful and potentially life-saving exercise. The fire evacuation drill and the accompanying open class were not merely routine activities; they were invaluable lessons in resilience, preparedness, and the valueof working together as a community to ensure our collective well-being.In the face of potential danger, it is easy to feel helpless or overwhelmed. However, this experience has taught me that through proper training, vigilance, and a commitment to following established protocols, we can empower ourselves to respond effectively and increase our chances of survival. It is a lesson that will stay with me long after I have left the halls of this institution, serving as a constant reminder of the importance of being prepared for the unexpected.As I continue on my academic journey, I carry with me the knowledge and skills imparted by this fire evacuation drill and open class. They have become an integral part of my personal growth and development, shaping my understanding of safety, responsibility, and the value of community. In a world where emergencies can strike at any moment, these lessons will undoubtedly prove invaluable, equipping me with the tools to navigate life's challenges with confidence and resilience.。
火灾条件下蚂蚁逃生行为实验
Vol. 32,No. 1Mar. 2020第32卷第1期2020年3月河南工程学院学报(自然科学版)JOURNAL OF HENAN UNIVERSITY OF ENGINEERING 火灾条件下蚂蚁逃生行为实验杜学胜(河南工程学院资源与安全工程学院，河南郑州451191)摘要：对常用人员疏散方法进行了对比分析，选择动物实验研究逃生问题。
以日本弓背蚁为实验对象,描述了蚂蚁的 社会组织，设计制作了两侧布房双出口实验装置，实验装置分成4个隔间，每个隔间放置不同的火灾环境变量，观察记录了火 灾时蚂蚁的逃生行为。
实验发现：蚂蚁会对新环境进行探查，然后将信息传递到整个蚁群；不同浓度的烟气对蚂蚁的刺激作 用不同，烟气浓度达到一定程度后，蚂蚁会迷失方向，甚至死亡；蚂蚁倾向选择最近的出口逃生，如果逃生通道被阻塞，蚂蚁会 探测并选择其他路径。
分析蚂蚁的逃生行为对人类的安全疏散有一定的借鉴作用。
关键词：火灾；蚂蚁；逃生行为；动物实验中图分类号:X932 文献标志码：A 文章编号= 1674 -330X(2021 )01 -0039 -04Experiment analysis of ant escape behavior under fire conditionsDU Xuesheng^College of Resources and Safety Engineering , Henan University of Engineering, Zhengzhou 451191, China)Abstract ： This paper analyzes the common research methods of personnel evacuation , and chooses the animal experiment to study the problem of escape. The social organization of ants was described. A double-exit experimental device with rooms in two sides for the camponotus japonics was designed and made. The experimental device was divided into f (>ur compartments, in each compartment placed with different fire environment variables. The escape beliavior of ants during fire was observed and recorded. Experimental ob- seivation shows that ants explore new environments and then transmit information to tlie entire colony. Different concentrations of smoke have diflerent stimulating effects on ants. When the concentration of smoke increases to a certain limit, ants may lose their orientation and even die. Ants tend to choose the nearest exit, if the escape route is blocked, the ants explore and choose other routes. The obser vation and analysis of ant's escape behavior serve as ieference to human's safe evacuation.Key w ords ： fire disaster ； ant ； escape behavior ； animal experiment随着城市化进程的日益加快，近年来大量人口涌入城市，城市中山现了很多超高层建筑和超大体量公 共建筑，人员密集场所越来越多。
幼儿园设置安全逃生窗计划方案及措施内容
幼儿园设置安全逃生窗计划方案及措施内容Kindergarten Safety Escape Window Plan: Measures and StrategiesEnsuring the safety of children in a kindergarten settingis of utmost importance. One vital aspect of this is having a well-defined safety escape window plan that includes effective measures and strategies to address emergency situations. In this article, we will discuss in detail the components of such a plan without using transitional phrases.Emergency Preparedness:In any emergency situation, it is crucial for the staff and children to be well prepared. They should undergo regular training sessions to familiarize themselves with the escape plan. The plan should be clearly communicated to parents so that they are aware of the procedures in case of an emergency.应急准备：在任何紧急情况下，员工和孩子们都需要做好充分的准备。
他们应定期接受培训，熟悉安全逃生计划。
计划应明确告知家长，使他们了解紧急情况下的程序。
龙之谷水上乐园英文作文介绍
龙之谷水上乐园：欢乐的水上乐园之旅**Dragon Valley Water Park: A Joyful Journey in the Aquatic Wonderland**Nestled amidst the verdant hills and surrounded by lush greenery, Dragon Valley Water Park offers a refreshing escape from the hustle and bustle of daily life. This magnificent aquatic paradise is a testament to the perfect blend of nature and modern amusement, providing visitors with an unforgettable experience.Upon arrival, the vibrant atmosphere welcomes you with open arms. The park is home to a diverse range of water rides, each unique in its own way. The thrilling Dragon's Den, a high-speed waterslide that sends riders plunging down a near-vertical drop, is a must-try for adrenaline junkies. For those seeking a more relaxed experience, the Lazy River offers a leisurely float down a calm stream, taking in the scenic views while soaking up the sun.The kids' section, known as Dragon Tots' Playland, is a delightful haven for the younger ones. With water-based play structures designed specifically for them, it's aplace where imagination and fun merge seamlessly. Parents can relax while watching their children splash and giggle, safe in the knowledge that they are in a safe and supervised environment.The Wave Pool, on the other hand, is a favourite among families and friends. Here, waves gently lap at the shore, simulating the feeling of being at the beach. It's an ideal spot to soak up the sun, have a picnic, or simply enjoy the serene atmosphere.What's more, Dragon Valley Water Park also boastsstate-of-the-art facilities, ensuring a comfortable and enjoyable experience for all. The cleanliness of the water is meticulously maintained, and the park staff are friendly and attentive, always ready to assist.As the sun sets, the park comes alive with acaptivating light show and fireworks display, marking the end of a perfect day. Visitors are treated to a visual feast while floating peacefully in the water, making for a truly memorable conclusion to their visit.In conclusion, Dragon Valley Water Park is not just a water park; it's an experience that leaves a lastingimpression on all who visit. From the thrilling rides to the serene pools, it caters to the needs of every visitor, young and old. It's a place where fun and relaxation merge, creating memories that last a lifetime.**龙之谷水上乐园：欢乐的水上乐园之旅**坐落在郁郁葱葱的山丘之中，四周环绕着绿意盎然的植被，龙之谷水上乐园为忙碌的日常生活带来了一丝清凉的慰藉。
英语作文消防演练活动
Fire Drill Practice: Enhancing SafetyAwareness and PreparednessIn the realm of safety and emergency preparedness, fire drills play a pivotal role. They are not mere simulations but crucial exercises that prepare individuals, communities, and organizations to respond effectively in the event of a real fire emergency. Recently, our school conducted a comprehensive fire drill, emphasizing the importance of safety awareness and preparedness among students and staff. The fire drill commenced with a resounding alarm, simulating the emergency situation. Students and teachers, accustomed to regular safety drills, reacted promptly. The evacuation process was orderly and swift, with students following designated escape routes and teachers guidingthem calmly. The use of clear signage and well-planned evacuation routes ensured that there was no confusion or panic.During the drill, special attention was paid toensuring that all individuals, including those with special needs, were accounted for and safely evacuated. Theschool's safety team, equipped with first aid kits and fire extinguishers, stood ready to assist in case of any mishap. Upon reaching the designated assembly areas, teachers took roll calls to ensure that everyone was present and accounted for. The fire department, invited for the occasion, gave a brief talk on fire safety measures, emphasizing the importance of staying calm, using fire extinguishers correctly, and calling emergency services promptly. They also demonstrated the proper usage of fire extinguishers and evacuation procedures.The drill concluded with a debriefing session, wherethe school administration, teachers, and the fire department discussed the effectiveness of the drill, identified areas for improvement, and emphasized the needfor continued vigilance and readiness. The administration expressed its gratitude to the fire department for their valuable insights and support.This fire drill not only reinforced our safety procedures but also highlighted the importance ofcontinuous training and education in emergency preparedness. It was a valuable lesson for all involved, reminding usthat safety is everyone's responsibility and that being prepared is the best way to protect ourselves and our loved ones.**消防演练活动：增强安全意识和准备能力**在安全和应急准备领域，消防演练发挥着至关重要的作用。
自然灾害安全教育活动的英语作文
自然灾害安全教育活动的英语作文Natural Disaster Safety: Learning to Be PreparedHi there! My name is Sarah and I'm a 4th grader at Oakwood Elementary School. Last month, we had a really cool set of activities at our school all about learning what to do in case of natural disasters like earthquakes, hurricanes, floods, and more. It was so much fun and I learned a ton of important stuff that could help keep me and my family safe if a disaster ever happens near us. Let me tell you all about it!It started with an assembly where a few people from the local emergency management office came and talked to all of us students about the different types of natural disasters that can occur in our area. They explained that we live in an earthquake-prone region near the coast, so we have to be ready for earthquakes as well as things like tsunamis, flash floods, and severe storms.They showed us some pretty scary videos of past earthquakes and tsunamis, but they said the reason they were showing us those videos wasn't to scare us. It was so we could understand just how powerful these natural forces can be and why it's so important to know what to do when they strike. Afterall, knowledge is power, and the more we know about how to stay safe, the better protected we'll be.Next up, the really fun part – we got to practice what to do during an earthquake drill! The teachers told us that whenever we feel strong shaking, the first thing we need to do is drop down onto our hands and knees. Then we should crawl under our desks or a sturdy table and hold onto the legs, covering our heads and necks with our other arm.We weren't just told this though, we actually got to practice it! When the alarm went off and the ground started shaking (don't worry, it was just a recording playing over the loudspeakers!), we all dropped, took cover, and held on tight. It was kind of like a big game of pretend, but it helped reinforce the motion we need to go through in a real quake. Practicing made it feel much more natural.After the shaking stopped, our teachers talked to us about the next step – evacuating safely. We lined up and followed them outside to our designated evacuation area on the playground. They stressed how important it is to stay calm, not run, and carefully watch for any fallen debris or downed power lines as we exit the building.While we were outside, the emergency crew played another recording simulating the sound of an incoming tsunami warning siren. Our principal explained that if we ever heard that sound, it would mean a big wave could be coming ashore soon, so we'd need to immediately go to higher ground or inland as fast as possible. They had us practice an evacuation drill where we walked quickly to the pre-determined tsunami safety zone a few blocks away.After all the shaking and siren practice, we got to check out some really cool emergency gear, like search and rescue equipment, utility trucks, and fire engines. The firefighters let us try on some of their heavy protective suits and breathing equipment too! We all felt like real heroes.One of my favorite parts was when they taught us how to put together emergency supply kits with basic things we'd need if we got stuck at home for a while after a disaster. We made little backpacks with food, water, first aid supplies, radios, flashlights, blankets, and other essentials. Now I keep my kit under my bed so I'll be ready to grab it if we ever need to evacuate or take shelter quickly.The very last activity was about making an emergency plan with our families. We had to go home and talk with our parentsabout designating a safe meeting place in case we got separated, as well as planning escape routes and discussing how we'd communicate if the phones were down. My family decided we'd meet at the park near our house, and we're going to start leaving notes for each other in the backyard shed with updates in case cell service gets disrupted.Overall, it was such a valuable experience learning about natural disaster preparedness. I feel so much more knowledgeable and empowered now about what to do in an emergency situation. The activities really drove home that while natural disasters can be scary, there are steps we can take to minimize the danger and survive if one strikes. As long as we stay aware, make a plan, and practice what to do, we'll be as ready as we can possibly be.I hope we never actually have to use these skills for real, but I'm glad my school gave us the tools to respond safely if needed. Natural disasters may be unavoidable, but now I know the key is being educated and prepared rather than caught off guard. If an earthquake, hurricane, or tsunami ever heads our way, my family and I will be ready to weather the storm!。
原地跑步游戏的英语作文
原地跑步游戏的英语作文Title: The Thrilling World of In-place Running Games。
In the realm of physical fitness and gaming, one trend has recently gained remarkable traction: in-place running games. These innovative games seamlessly blend physical activity with the immersive experience of gaming, offering a dynamic way to stay active while having fun. In this essay, we will delve into the world of in-place running games, exploring their benefits, gameplay mechanics, and impact on physical well-being.First and foremost, let's discuss the essence of in-place running games. Unlike traditional video games that confine players to a stationary position, these games encourage physical movement, simulating the sensation of running within a limited space. Whether it's jogging through virtual landscapes or participating in exhilarating races, players are required to engage their bodies to navigate through the game world.One of the key benefits of in-place running games lies in their ability to promote physical activity in an enjoyable and accessible manner. In today's digital age, sedentary lifestyles have become increasingly prevalent, contributing to various health issues such as obesity and cardiovascular problems. In-place running games offer a refreshing alternative by enticing individuals of all ages to get moving. By gamifying the act of running, these games motivate players to surpass their physical limitations and strive for personal fitness goals.Moreover, in-place running games foster a sense of community and competition among players. Through online multiplayer modes and leaderboards, participants can challenge friends or compete against global rivals, fostering a spirit of camaraderie and healthy competition. This social aspect adds an extra layer of excitement to the gaming experience, encouraging players to stay engaged and motivated in their fitness journey.Now, let's delve into the gameplay mechanics of in-place running games. Most titles in this genre utilize motion-sensing technology or wearable devices to track players' movements accurately. By syncing with smartphonesor gaming consoles, these games can detect steps, speed,and distance traveled, translating real-world actions intoin-game progress. Whether it's running on the spot, jumping, or performing agility exercises, players must actively engage their bodies to control their in-game avatars.In addition to traditional running mechanics, many in-place running games incorporate elements of adventure and exploration. Players may find themselves traversing through virtual forests, sprinting across futuristic cityscapes, or embarking on epic quests to defeat virtual foes. These immersive environments captivate players' imaginations, providing a welcome escape from the monotony of everydaylife while promoting physical activity.Furthermore, in-place running games often feature customizable options that cater to players' preferences and fitness levels. From adjustable difficulty settings to personalized workout routines, these games empowerindividuals to tailor their gaming experience according to their unique needs and goals. Whether you're a fitness enthusiast looking for a high-intensity workout or a casual gamer seeking a leisurely jog, there's a wide range of options available to suit every player's lifestyle.In conclusion, in-place running games represent a groundbreaking fusion of gaming and physical fitness, offering a fun and engaging way to stay active. By combining immersive gameplay with real-world movement, these games inspire players to embrace a healthierlifestyle while having a blast in the process. As the popularity of in-place running games continues to soar, they have the potential to revolutionize the way we perceive exercise and redefine the boundaries ofinteractive entertainment. So why not lace up your virtual sneakers, embark on a thrilling adventure, and experience the excitement of in-place running games for yourself?。
你如何正确逃生英语作文
你如何正确逃生英语作文Title: How to Escape Safely: A Guide to Emergency Situations。
In today's unpredictable world, knowing how to escape safely from various emergency situations is paramount. Whether it's a fire, a natural disaster, or a terrorist attack, being prepared and having a plan can make all the difference. In this essay, we will explore essential strategies and tips for effective escape in English.Understanding Emergency Escape Routes:First and foremost, it's crucial to familiarizeyourself with the escape routes in any building or area you frequent. Whether it's your workplace, school, or home, know where the exits are located and how to access them quickly. Additionally, identify alternative routes in case primary exits are blocked.Remain Calm and Think Rationally:During an emergency, panic can cloud judgment and impede escape efforts. Therefore, it's essential to remain calm and think rationally. Take a few deep breaths to steady yourself and assess the situation calmly. Remember, a clear mind can help you make better decisions and navigate obstacles more effectively.Alert Others and Call for Help:If possible, alert others about the emergency and call for help immediately. This could involve activating fire alarms, shouting for assistance, or using emergency communication devices such as phones or walkie-talkies. Prompt action can help minimize harm and facilitate a quicker response from emergency services.Use Available Resources:In emergency situations, use any available resources to aid your escape. This could include fire extinguishers tocombat small fires, ropes or ladders for descending from heights, or improvised tools for breaking through barriers. Be resourceful and creative in utilizing your surroundings to enhance your chances of survival.Follow Safety Protocols:Many buildings and institutions have established safety protocols and procedures for various emergencies. Familiarize yourself with these protocols and follow them diligently. This might involve assembly points for evacuations, designated shelter areas during storms, or lockdown procedures during security threats. Adhering to established protocols can ensure a coordinated and organized response to emergencies.Stay Informed and Prepared:Stay informed about potential risks and hazards in your environment and take proactive measures to mitigate them. This could involve attending safety training sessions, participating in emergency drills, and staying updated onrelevant news and alerts. Additionally, maintain an emergency kit with essential supplies such as water, food, first aid supplies, and flashlights in case of prolonged emergencies.Assist Others When Possible:During emergencies, if it's safe to do so, assist others who may need help escaping. This could include elderly individuals, children, or individuals with disabilities who may require assistance. Remember, collective cooperation and support can increase everyone's chances of survival.Practice Regularly:Lastly, practice emergency evacuation drills regularly to reinforce escape procedures and familiarize yourself with the actions to take in different scenarios. This could involve conducting fire drills at home, workplace, or school, practicing earthquake drills, or simulating evacuation procedures for other potential emergencies.Regular practice builds confidence and muscle memory, enabling you to react quickly and effectively when faced with a real emergency.In conclusion, knowing how to escape safely from various emergency situations is a crucial life skill. By understanding escape routes, remaining calm, alerting others, utilizing available resources, following safety protocols, staying informed and prepared, assisting others, and practicing regularly, you can enhance your chances of survival and help others in need during times of crisis. Remember, preparation and quick thinking are key to escaping safely from any emergency.。
关于海底火山的小实验的英语作文
关于海底火山的小实验的英语作文The Enthralling Experiment: Unveiling the Secrets of Submarine Volcanoes.In the depths of our oceans, concealed beneath the enigmatic surface, lies a captivating world of volcanic activity – a realm of fire and fury that shapes ourplanet's very existence. Submarine volcanoes, these enigmatic titans, offer a glimpse into the dynamic processes that have molded our world for millennia. To delve into the complexities of these underwater wonders, we embark on a thrilling experiment, unlocking the secrets of their formation and explosive eruptions.Materials Required:A large glass or plastic container (e.g., a clear plastic bottle or a glass jar)。
White vinegar.Baking soda.Red food coloring.Blue food coloring.Water.A small balloon.A pair of scissors.Procedure:1. Volcanic Crucible: Begin by filling the glass container about three-quarters full with water. This will serve as our simulated ocean.2. Eruptive Essence: In a separate bowl, combine equal parts white vinegar and water. This concoction will act as the eruptive magma.3. Carbonate Catalyst: In another bowl, dissolve one tablespoon of baking soda in a small amount of water. The baking soda will act as the catalyst for our eruption.4. Gas Giant: Trim the end off the balloon, leaving a small opening. Stretch the balloon over the mouth of the glass or plastic container. This will represent the submarine volcano's vent, where gas and magma will escape.5. Chromatic Currents: Add a few drops of red food coloring to the vinegar solution to simulate the fiery magma. For the surrounding water, add a few drops of blue food coloring to create a realistic ocean hue.6. Eruption Trigger: Carefully pour the vinegarsolution into the glass container, being sure not tooverfill it. The vinegar will react with the baking soda, producing carbon dioxide gas.7. Magma Upsurge: As the carbon dioxide gas bubbles rise, it will carry the vinegar solution upward, creating avivid simulation of a volcanic eruption.Observations:As the experiment unfolds, we witness the fascinating spectacle of a submarine volcanic eruption. The red-tinged vinegar solution vigorously ascends through the water column, resembling the fiery magma of a real volcano. The blue water around the eruption site churns and froths, mimicking the turbulence created by the escaping gas and ash.Submarine Volcano Formation:This experiment not only demonstrates the mechanics of a volcanic eruption but also provides insights into the formation of submarine volcanoes. The carbon dioxide gas bubbles, analogous to molten magma, rise through the surrounding water due to their lower density. Over time, the accumulation of magma builds up into a volcanic cone beneath the ocean's surface.Eruptive Mechanisms:The interplay between the vinegar (magma) and baking soda (carbonate) mirrors the real-world processes that trigger volcanic eruptions in the ocean. When magma comes into contact with water, it rapidly cools and solidifies. This sudden cooling process causes the water to expand and turn into steam, generating immense pressure within the volcano. When the pressure exceeds the strength of the overlying rock, an eruption occurs.Environmental Impact:Submarine volcanoes play a crucial role in shaping our oceans and the Earth's atmosphere. Their eruptions release nutrients into the water column, providing sustenance for marine life. Additionally, the gases emitted during eruptions can interact with the atmosphere, influencing cloud formation and climate patterns.Conclusion:Our captivating experiment has illuminated the complexities of submarine volcanoes, providing a deeper understanding of their formation and eruptive behavior. By simulating these underwater phenomena, we gain valuable insights into the dynamic processes that shape our planet's oceans and atmosphere. May this experiment inspire further exploration into the enigmatic realm of submarine volcanoes, unlocking the secrets that lie hidden beneath the surfaceof our world.。
去广州正佳广场海洋馆作文英语
去广州正佳广场海洋馆作文英语Visiting the Ocean World at Guangzhou ZhengjiaPlazaNestled in the heart of Guangzhou's bustling Tianhe District, Zhengjia Plaza stands as a beacon of entertainment and education, offering visitors a unique escape into the wonders of the ocean. Among its many attractions, the Ocean World at Zhengjia Plaza is a must-visit destination for anyone fascinated by marine life. Recently, I had the privilege of exploring this underwater kingdom, and the experience left me awestruck.The Grand EntranceStepping into the Ocean World, I was immediately greeted by a grand entrance that set the tone for the adventure ahead. The vast space, filled with shimmering lights and the sounds of the sea, transported me from the bustling city streets to a serene underwater world.Diverse Exhibits and Thematic AreasThe Ocean World boasts a staggering 58,000 square meters of exhibition space, divided into ten captivating thematic areas, each with its own charm and educational value. From the "Life's Origin" exhibit, which features a stunning 270° panoramic tunnel simulating the birth ofthe universe and the earth, to the "Rainforest Lakes," which showcases the beauty and importance of protecting rainforests and lakes, every corner of the Ocean World is a feast for the senses.One of the highlights for me was the "Jellyfish Secret Garden." Here, thousands of jellyfish of various shapes and colors float gracefully in cylindrical tanks, creating a mesmerizing display of bioluminescence. The "Ocean Carnival" area, on the other hand, is home to an array of colorful fish and majestic sharks, providing a glimpse into the vibrant underwater ecosystem.Interactive Experiences and PerformancesBut the Ocean World's appeal extends far beyond its stunning exhibits. The park offers a plethora of interactive experiences that allow visitors to engage with marine life up close. Feeding sessions, where guests can assist the trainers in nourishing the fish and other sea creatures, are particularly popular among children and adults alike.Moreover, the Ocean World hosts several live performances throughout the day, including the breathtaking "Mermaid Legend" show. Watching the mermaids glide gracefully through the water, accompanied by a symphony of music, was a truly magical experience. The "Animal Rock Band" performance, featuring sea lions and other marine mammals playing instruments, was equally entertaining and educational.Conservation and EducationBeyond its entertainment value, the Ocean World is also dedicated to conservation and education. The park's numerous displays and interactive exhibits are designed to raise awareness about the importance of protecting marine life and the oceans. Through these engaging experiences, visitors are encouraged to adopt sustainable practices and become advocates for the preservation of our blue planet.ConclusionIn conclusion, my visit to the Ocean World at Guangzhou Zhengjia Plaza was an unforgettable journey into the depths of the sea. From its diverse exhibits and thematic areas to its interactive experiences and captivating performances, the park offers something for everyone. But perhaps most importantly, it serves as a powerful reminder of the beauty and fragility of our ocean ecosystem, inspiring visitors to take action and protect this vital part of our planet.。
消防演练的内容英语作文
英语作文：Fire Drill ContentFire drills are essential components of emergency preparedness in any organization, school, or residential complex. They aim to educate individuals on the importance of swift and orderly evacuation in case of a fire emergency, as well as familiarize them with the necessary safety procedures. Below is an overview of the typical content covered during a comprehensive fire drill.1. Pre-Drill BriefingPrior to the drill, participants are gathered for a brief introduction, emphasizing the purpose and importance of the exercise. Safety officers explain the evacuation plan, including designated meeting points, escape routes, and the role of each individual, such as fire wardens and first responders.2. Evacuation Procedure DemonstrationA demonstration is conducted to showcase the correct way to evacuate, including staying low to avoid smoke inhalation, using the stairs instead of elevators, and keeping calm during the process. Special attention is given to assisting those with disabilities or mobility issues.3. Activation of Emergency SystemsThe fire alarm system is activated, simulating a real-life emergency scenario. This triggers an immediate response from all participants, who begin the evacuation process according to the pre-determined plan.4. Evacuation in ActionParticipants evacuate their respective areas, following the designated routes and maintaining order. Fire wardens ensure that no one is left behind and guide evacuees to the safety meeting points. During this phase, communication is crucial to keep everyone informed and updated.5. Headcount and AccountabilityOnce at the safety meeting points, roll calls are conducted to ensure everyone has evacuated safely. This accountability process is vital for identifying any missing persons and initiating search-and-rescue operations if necessary.6. Post-Drill DebriefingAfter the evacuation is complete, a debriefing session is held to discuss the drill's performance. Positive aspects are acknowledged, while areas for improvement are identified and addressed. This feedback loop is essential for refining the evacuation plan and enhancing future preparedness.7. Safety Reminders and Follow-UpParticipants are reminded of basic fire safety measures, such as keeping fire exits clear, practicing fire prevention, and knowing how to use fire extinguishers. Follow-up training or workshops may be scheduled to further enhance knowledge and skills.中文翻译：消防演练内容消防演练是任何组织、学校或住宅区域应急准备工作中不可或缺的一部分。
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1. Introduction
Large public places such as airports, railway stations, supermarkets, gymnasia and theaters are daily venues for commercial and social activities and are therefore densely occupied by pedestrians. Such dense activity is also evident at peak morning and evening travel times, lunchtime shopping, public holiday celebrations, etc. Dense crowds have the potential to become impenetrable or to develop into what can be termed as an unsteady state with turbulent flows (Helbing and Johansson 2007, Yu and Johansson 2007, Ma et al. 2013). Under these conditions, there exists the possibility of crowd alarm, panic, and hysteria, which can compromise individual safety. In many instances, fatalities and injuries are not caused by exogenous factors such as fire, explosions, poisonous gas, or other external hazards, but by crowd behavior itself (Helbing et al. 2005). During evacuations, or even in normal circumstances, all members require information that allows them to make optimal use of all viable exits. Such information can be extremely vital in cases of emergency. In such cases, an understanding of the fundamental features of pedestrian
This article was downloaded by: [61.132.138.212] On: 14 December 2014, At: 17:38 Publisher: Institute for Operations Research and the Management Sciences (INFORMS) INFORMS is located in Maryland, USA
Jiancheng Long
School of Transportation Engineering, Hefei University of Technology, Hefei 230009, China, jianchenglong@
Hai-Jun Huang
School of Economics and Management, Beihang University, Beijing 100191, China, haijunhuang@
Operations Research
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Simulating the Dynamic Escape Process in Large Public Places
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Simulating the Dynamic Escape Process in Large Public Places
Pedestrian dynamics plays an important role in public facility design and evacuation management. During an escape process from a large public space, crowd behavior is a collection of pedestrian exit/route choice behavior, and movement behavior. Modelling such an escape process is an extremely complex challenge. In this paper, an integrated macro-micro approach is developed to simulate the escape process. An analysis of the simulation reveals the mechanisms of the formation of crowd congestion and flow distribution. At the macroscopic level, a mathematical model, based on the concept of the dynamic user optimal (DUO) criterion, is formulated to describe the pedestrian exit/route choice behavior. A method based on the fundamental diagram and point-queuing theory is developed to estimate the pedestrian escape time. At the microscopic level, a modified social force model is adopted to formulate pedestrians’ dynamic movements during the escape process. A solution algorithm is proposed to solve the macro-micro integrated model and a series of experiments are carried out to validate the proposed model. The simulation results agree with the extracted experimental data. Finally, the integrated model and algorithm are used to simulate the escape process in a large public place. The proposed approach is able to generate the bandwagon effect, bottleneck effect, and route choice patterns. Subject classifications : large public places; escape process; dynamic route choice; simulation; travel time estimation. Area of review : Transportation. History : Received November 2011; revisions received March 2013, October 2013, February 2014, April 2014; accepted August 2014. Published online in Articles in Advance September 29, 2014.
Ziyou Gao, Yunchao Qu, Xingang Li
School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China {zygao@, 07121217@, lixingang@}
Ziyou Gao, Yunchao Qu, Xingang Li, Jiancheng Long, Hai-Jun Huang
To cite this article: Ziyou Gao, Yunchao Qu, Xingang Li, Jiancheng Long, Hai-Jun Huang (2014) Simulating the Dynamic Escape Process in Large Public Places. Operations Research 62(6):1344-1357. /10.1287/opre.2014.1312 Full terms and conditions of use: /page/terms-and-conditions This article may be used only for the purposes of research, teaching, and/or private study. Commercial use or systematic downloading (by robots or other automatic processes) is prohibited without explicit Publisher approval, unless otherwise noted. For more information, contact permissions@. The Publisher does not warrant or guarantee the article’s accuracy, completeness, merchantability, fitness for a particular purpose, or non-infringement. Descriptions of, or references to, products or publications, or inclusion of an advertisement in this article, neither constitutes nor implies a guarantee, endorsement, or support of claims made of that product, publication, or service. Copyright © 2014, INFORMS Please scroll down for article—it is on subsequent pages