| A group is a mixture of individuals and groups,not a pure collection of individuals.The existence of different types of groups may have a great impact on the dynamic characteristics of the group,and finally affect the pattern and movement of the whole population.However,most evacuation group movement models do not fully consider the behavior characteristics of these groups.In order to make the movement model more fit the actual movement state,it is necessary to study the group movement process in depth.Therefore,this paper explores the motion characteristics and influencing factors of small groups of different sizes.First,Kinovea software was used to track the personnel trajectory of 100 small groups of 2 people,100 small groups of 3 people,50 small groups of 4 people and 10 small groups of 5 people in the IMAX theater and convert them into coordinate points in the plane coordinate system.Secondly,the degree centrality analysis was used to identify the central figures in each group.The distance between the group members and the central figure is the group distance.Then use the coordinates of the trajectory of the person to calculate the distance between adjacent members,the angle between the adjacent members,the speed of the central person and the group members and other characteristics of group movement.Finally,statistically analyze the impact of evacuation factors such as different gender ratios,different height differences,different personnel densities,presence or absence of confluence on group distances.The conclusions obtained in this article are as follows:（1）The probability distribution of the group distance of small groups of different sizes is significantly different,and the larger the group size,the greater the distance within the group.The average group distances of small groups of different sizes were 60.06±4.12cm,73.47±3.90cm,82.79±5.15cm,and 83.47±10.65cm.（2）When the group size is 2 people,d12=60.06±4.12cm;when the group size is 3people,d12=60.26±7.39cm,d23=68.39±6.53cm;when the group size is 4 people,d12=49.45±5.75cm,d23=73.55±9.65cm,d34=46.74±4.23cm;when the group size is 5 people,d12=64.515.54cm,d23=69.24±10.71cm,d34=87.95±25.76cm,d45=43.86±7.94cm.Under different scale conditions,there is no significant difference in the distance between P1P2 and P2P3,and there is a significant difference in the distance between P3P4.（3）When the group size is 2 people,α12=45.85?±2.14?;when the group size is 3people,α12=35.54?±2.65?、α23=35.61?±2.15?;when the group size is 4 people,α12=42.47?±3.06?、α23=34.50?±2.56?,α34=36.12?±3.09?;when the group size is 5 persons,α12=39.61?±6.78?,α23=38.87?±6.16?,α34=33.58?±4.98?,α45=为47.22?±6.22?.The angles of P1P2and P4P5 in different size groups were significantly different,while there was no significant difference between P2P3 and P3P4.（4）The average speeds of the center figures of small groups of different group sizes are 0.27±0.01m/s,0.25±0.01m/s,0.23±0.01m/s,0.30±0.04m/s.When the group distance is less than the average,the speed difference between the group members and the central figure is-0.15-0.1m/s、-0.2-0.15m/s、-0.15-0.15m/s、-0.25-0.15m/s,respectively.（5）When there are more women in a group than men,the group distance is relatively small.The group size is 3 or less.When the height difference of group members is greater than 30cm,the greater the height difference,the greater the group distance;when the group size is greater than 3 people,and the group member height difference is greater than 20cm,the greater the height difference,the greater the group distance.When the group size is 2 or 4people,the group distance decreases first and then increases with the increase of the personnel density.The group distance when the personnel density is 1.0-1.5 people/m2 is relatively small.When the group size is 3 or 5 people,the group distance decreases as the density of people increases.When there are people coming in front of the group,the group distance is reduced. |
