Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model
The cellular automata (CA) model has been a meaningful way to study pedestrian evacuation during emergencies, such as fires, for many years. Although the time step used in the CA model is one of the most essential elements, there is a lack of research on its impact on evacuation time. In this paper,...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-03-01
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| Series: | Fire |
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| Online Access: | https://www.mdpi.com/2571-6255/7/3/100 |
| _version_ | 1797241082345422848 |
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| author | Hongpeng Qiu Xuanwen Liang Qian Chen Eric Wai Ming Lee |
| author_facet | Hongpeng Qiu Xuanwen Liang Qian Chen Eric Wai Ming Lee |
| author_sort | Hongpeng Qiu |
| collection | DOAJ |
| description | The cellular automata (CA) model has been a meaningful way to study pedestrian evacuation during emergencies, such as fires, for many years. Although the time step used in the CA model is one of the most essential elements, there is a lack of research on its impact on evacuation time. In this paper, we set different time step sizes in an extended cellular automaton model and discuss the effect of time step size on the overall evacuation time under different emergency types and levels. For a fixed step time mode, the larger the time step, the longer the evacuation time. In each time step size, the evacuation time gradually increases with the increase of emergency level, and there is a sharp increase when the time for pedestrians to move one step is exactly an integer multiple of the time step. When there is no friction between pedestrians, the evacuation time at each time step first decreases slightly with the increase of emergency level and then remains unchanged; the larger the time step, when the evacuation time remains unchanged, the lower the emergency level and the greater the evacuation time. For the variable time step model, when the friction between pedestrians approaches infinity, the total evacuation time does not change with the emergency level; when the friction between pedestrians is reduced, the total evacuation time slightly decreases with the increase of the emergency level. The less friction there is, the more significant the reduction. The results of previous actual experiments are also reflected in the simulation at a lower emergency level. The result shows that the time step size significantly impacts the evacuation simulation results of the CA model, and researchers should choose carefully to obtain more realistic simulation results. |
| first_indexed | 2024-04-24T18:17:40Z |
| format | Article |
| id | doaj.art-16cc2764860c4bd5a5da04c5b64112e0 |
| institution | Directory Open Access Journal |
| issn | 2571-6255 |
| language | English |
| last_indexed | 2024-04-24T18:17:40Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Fire |
| spelling | doaj.art-16cc2764860c4bd5a5da04c5b64112e02024-03-27T13:38:14ZengMDPI AGFire2571-62552024-03-017310010.3390/fire7030100Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata ModelHongpeng Qiu0Xuanwen Liang1Qian Chen2Eric Wai Ming Lee3Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, ChinaDepartment of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, ChinaDepartment of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, ChinaDepartment of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, ChinaThe cellular automata (CA) model has been a meaningful way to study pedestrian evacuation during emergencies, such as fires, for many years. Although the time step used in the CA model is one of the most essential elements, there is a lack of research on its impact on evacuation time. In this paper, we set different time step sizes in an extended cellular automaton model and discuss the effect of time step size on the overall evacuation time under different emergency types and levels. For a fixed step time mode, the larger the time step, the longer the evacuation time. In each time step size, the evacuation time gradually increases with the increase of emergency level, and there is a sharp increase when the time for pedestrians to move one step is exactly an integer multiple of the time step. When there is no friction between pedestrians, the evacuation time at each time step first decreases slightly with the increase of emergency level and then remains unchanged; the larger the time step, when the evacuation time remains unchanged, the lower the emergency level and the greater the evacuation time. For the variable time step model, when the friction between pedestrians approaches infinity, the total evacuation time does not change with the emergency level; when the friction between pedestrians is reduced, the total evacuation time slightly decreases with the increase of the emergency level. The less friction there is, the more significant the reduction. The results of previous actual experiments are also reflected in the simulation at a lower emergency level. The result shows that the time step size significantly impacts the evacuation simulation results of the CA model, and researchers should choose carefully to obtain more realistic simulation results.https://www.mdpi.com/2571-6255/7/3/100emergency levelsfriction levels‘faster-is-slower’ effecttime stepcellular automata |
| spellingShingle | Hongpeng Qiu Xuanwen Liang Qian Chen Eric Wai Ming Lee Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model Fire emergency levels friction levels ‘faster-is-slower’ effect time step cellular automata |
| title | Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model |
| title_full | Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model |
| title_fullStr | Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model |
| title_full_unstemmed | Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model |
| title_short | Effect of Different Time Step Sizes on Pedestrian Evacuation Time under Emergencies Such as Fires Using an Extended Cellular Automata Model |
| title_sort | effect of different time step sizes on pedestrian evacuation time under emergencies such as fires using an extended cellular automata model |
| topic | emergency levels friction levels ‘faster-is-slower’ effect time step cellular automata |
| url | https://www.mdpi.com/2571-6255/7/3/100 |
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