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As urban areas continue progressing into more complex development, urban areas become more vulnerable to disaster. Therefore, there is growing interest in investigating disaster response processes considering population distribution variation within urban regions. This study explores the unsupervised machine learning methods, K-means, DBSCAN, and introduces a novel Ensemble Clustering, which is compared to the established grid-based method as a framework for aggregating disaster victims in determining evacuation strategies. The Ensemble Clustering method combines the K-Means clustering strengths in dividing disaster victim distribution into globular cluster distribution. DBSCAN supports it as a robust outlier identification for disaggregating the irrelevant member as an individual. Subsequently, the clustering effectivity is evaluated by simulating the evacuation scenarios in the evacuation simulation, and the performance is compared to the traditional grid-based method. Combining the machine learning method and the evacuation simulation can be a framework for the decision-making process during a disaster. The results show that the Ensemble Clustering outperforms the traditional grid method, ensuring a faster completion time.

As environmental conservation and sustainability gain prominence globally, modern timber structures are receiving increased focus. Nonetheless, the combustible nature of timber raises significant fire safety concerns. This review explores the recent advancements in fire safety engineering for timber structures, emphasizing both contemporary high-rise buildings and historical timber constructions. It covers topics like inherently safer design principles, fire risk prediction, and evacuation methodologies. The review emphasizes the criticality of selecting suitable materials, structural design, firefighting systems, and advanced sensor technologies for early fire detection. Additionally, we analyze and compares various evacuation strategies, offering insights into the challenges and future directions for fire safety in modern timber structures. [ABSTRACT FROM AUTHOR]

Urbanization has led to increased construction of underground buildings to overcome limited surface space. However, safety concerns in urban underground commercial buildings have become a major issue due to frequent accidents. Ensuring safe evacuation in densely populated underground commercial buildings is crucial. This study focuses on the safe evacuation of an urban underground commercial street A in Fuzhou City. A simulation framework based on Building Information Modelling (BIM) is proposed, integrating the Fire Dynamic Simulator (FDS) and BIM. The framework overcomes limitations in fire dynamic simulators. Using a BIM model, the study analyzes the risk of each fire protection area and selects the most unfavorable area for simulation. PyroSim technology is employed to study the entire fire development process in the underground commercial street under three different fire scenarios. The analysis includes evacuation stair travel time and personnel available safe evacuation time (TASET). By comparing the results, the study optimizes building layout design and identifies factors affecting personnel evacuation efficiency. The simulation outcomes aim to minimize casualties and property losses, contributing to fire safety management in urban underground commercial streets.

As environmental conservation and sustainability gain prominence globally, modern timber structures are receiving increased focus. Nonetheless, the combustible nature of timber raises significant fire safety concerns. This review explores the recent advancements in fire safety engineering for timber structures, emphasizing both contemporary high-rise buildings and historical timber constructions. It covers topics like inherently safer design principles, fire risk prediction, and evacuation methodologies. The review emphasizes the criticality of selecting suitable materials, structural design, firefighting systems, and advanced sensor technologies for early fire detection. Additionally, we analyze and compares various evacuation strategies, offering insights into the challenges and future directions for fire safety in modern timber structures.

In recent years, more and more theaters with rotating mechanisms have been built and used, such as theaters with rotating auditoriums. The rotation mechanism in this type of building may lead to the uncertainty of evacuation distances and routes, which undoubtedly poses a higher challenge to performance-based fire protection design. Taking the revolving auditorium theater as an example, this paper proposes a systematic method to solve the problem of randomness in evacuation scenarios. The numerical simulations based on FDS and Pathfinder were carried out, and two improved evacuation strategies for theaters with rotating auditorium were proposed. The results show that the blockage of evacuation exits is an important factor affecting the success of evacuation and the evacuation time. In addition, the establishment of emergency evacuation stairs and rotating auditoriums can effectively reduce the evacuation time. [ABSTRACT FROM AUTHOR]

• A risk-based method for evacuation planning in chemical accidents is presented. • Cumulative individual risk is used as the evaluation index for evacuation strategy. • Multi-hazard characteristics and domino effects are considered in this method. • The method can decide whether to evacuate or shelter-in-place after an accident. • This method can be applied in the development of emergency response strategies. With the agglomeration and complication of the chemical industry, the multi-hazard and dynamic characteristics have become new challenges for chemical safety management and loss prevention research. As an important topic of safety research in chemical industries, the evacuation strategy also needs to be improved according to the new characteristics of chemical accidents. Here we propose a method for evacuation strategy development in chemical accidents based on dynamic and multi-hazard risk assessment. This method adopts the cumulative individual risk as the evaluation indicator for the optimal evacuation strategy. This method can dynamically consider the multi-hazard characteristics and domino effects of chemical accidents during the evacuation. A multi-hazard chemical accident that happened in Xiangshui, China in 2019 is taken as a case study to show the effects of risk assessment results on evacuation strategy development. The case shows that a reasonable time period for shelter-in-place after the occurrence of the primary accident can reduce the cumulative individual risk in the evacuation process. It is expected that this paper can provide guidance and reference for loss prevention in chemical industries, and can also provide useful tools for the management of emergency response. [ABSTRACT FROM AUTHOR]

• A BIM based simulation framework for fire emergency evacuation simulation. • Using PyroSim technology to analyze the influencing factors. • Considering the impact of fire products on evacuation. • Setting three scenarios to ensure the reliability of the study. • Focus on safe evacuation under the most unfavorable conditions. Urbanization has led to increased construction of underground buildings to overcome limited surface space. However, safety concerns in urban underground commercial buildings have become a major issue due to frequent accidents. Ensuring safe evacuation in densely populated underground commercial buildings is crucial. This study focuses on the safe evacuation of an urban underground commercial street A in Fuzhou City. A simulation framework based on Building Information Modelling (BIM) is proposed, integrating the Fire Dynamic Simulator (FDS) and BIM. The framework overcomes limitations in fire dynamic simulators. Using a BIM model, the study analyzes the risk of each fire protection area and selects the most unfavorable area for simulation. PyroSim technology is employed to study the entire fire development process in the underground commercial street under three different fire scenarios. The analysis includes evacuation stair travel time and personnel available safe evacuation time (TASET). By comparing the results, the study optimizes building layout design and identifies factors affecting personnel evacuation efficiency. The simulation outcomes aim to minimize casualties and property losses, contributing to fire safety management in urban underground commercial streets. [ABSTRACT FROM AUTHOR]

The passenger evacuation capacity (PEC) of a cruise ship is a pivotal guarantee for quickly and safely evacuating all personnel on a damaged ship during an emergency. A general framework of the agent-based evacuation model is proposed in this study to simulate the entire process of cruise ship evacuation. The total evacuation time, duration of Level of Service (LOS) lower than E, effective flow rate of the escape route, density of the muster station, and usage rate of the lifeboat/life raft are used as the five evaluation indicators to quantify the PEC of cruise ships, thus providing a reference for the optimization analysis of evacuation procedures. With this framework, the PECs under different evacuation strategies of a cruise ship were evaluated in the context of ship heeling to capsizing for the Yangtze Gold 1. Evaluation results show that the increase of heeling angle when the evacuation order is issued does not affect the perception time of the first 90% of evacuees, but significantly increases the total evacuation time after more than 20°. Moreover, the degree of regional congestion is affected by several factors, including the assignment of muster stations, evacuation in batches, the place of obtaining life jackets, the heeling angle, the difference of escape route flows, and other factors. The results of this study provide PECs under different strategies as references for specific accident scenarios and evacuation targets. [ABSTRACT FROM AUTHOR]

In China, training schools are ubiquitous, where heterogeneous pedestrian flow (which consists of adults and children) widely occurs during the after-class period. In this paper, we develop a fine grid cellular CA model to describe the pedestrian behaviors (e.g., pick-up behavior, searching behavior, matching behavior, waiting behavior, leading behavior, and following behavior) at a training school during the after-class period and explore the effects of the special behaviors on each pedestrian's movement in and around a classroom. To describe the heterogeneous pedestrian flow accurately, (i) some questionnaire surveys are designed to extract some features of adult's and child's movement, and (ii) some video experiments are conducted to estimate/calibrate some parameters of interest in the proposed model. Finally, some strategies are designed to enhance the evacuation efficiency and the operational efficiency of training school. The numerical results indicate that the proposed model can reasonably match with reality, and the proposed strategies can enhance the evacuation efficiency and the operational efficiency of training school. The results can help the administrators to effectively manage the pedestrian evacuation at training school during the after-class period. [ABSTRACT FROM AUTHOR]

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In recent years, more and more theaters with rotating mechanisms have been built and used, such as theaters with rotating auditoriums. The rotation mechanism in this type of building may lead to the uncertainty of evacuation distances and routes, which undoubtedly poses a higher challenge to performance-based fire protection design. Taking the revolving auditorium theater as an example, this paper proposes a systematic method to solve the problem of randomness in evacuation scenarios. The numerical simulations based on FDS and Pathfinder were carried out, and two improved evacuation strategies for theaters with rotating auditorium were proposed. The results show that the blockage of evacuation exits is an important factor affecting the success of evacuation and the evacuation time. In addition, the establishment of emergency evacuation stairs and rotating auditoriums can effectively reduce the evacuation time.

During the evacuation process in an emergency, the route conditions usually change instantaneously, which makes routing selection a challenging work. To describe dynamic changes in the evacuation environment, this work proposes a real-time evacuation strategy based on a comprehensive route constraint in the framework of a cell-inspired simulation model, intelligence decision P system (IDPS). In our model, the comprehensive route constraint is formed to describe more complex road condition information including the total distance, congestion state, and unreliability of the route. Meanwhile, the IDPS model has been further improved in both the knowledge base description and the decision-making ability. Experiments are conducted to simulate five different scenarios in a fire evacuation. The results show that the evacuation strategy with a comprehensive route constraint has a significant improvement in the evacuation efficiency and has higher robustness. Which kind of route condition should be emphasized more in different evacuation scenarios is also analyzed. [ABSTRACT FROM AUTHOR]

In view of the crowd evacuation exit selection strategy question of complex buildings， this paper focuses on the cognitive difference of pedestrians in the synthetic shortest distance. The mixed distance strategy is established by introducing the distance factor and density factor， and combined with the modified background field modeling rules. The exit selection strategy is integrated into the particle swarm updating mechanism， and the exit selection strategy based on particle swarm optimization with background field is established. The evacuation performance of exit selection strategy is simulated by numerical experiments. The experimental results reveal the mechanism of group movement in multi-exit buildings， and reflect the dynamic adjustment performance of the evacuation strategy. The simulated evacuation process verifies the rationality and effectiveness of the multi-exit selection of the mixed distance strategy in group evacuation. [ABSTRACT FROM AUTHOR]

With the constant growth of urban construction, metro station has being playing an increasingly important role in the public transportation system. To ensure the safe operation and the safety of the people, it is necessary to analyze how to select a suitable evacuation strategy while emergency event occurs in a metro station. The evacuation strategy selection can be regarded as a multiple criteria group decision making problem, which involves some conflict evaluation criteria. This paper presents an improved TOPSIS method to handle the evacuation strategy selection problem of metro station based on interval type-2 fuzzy sets. Firstly, the TOPSIS method in interval type-2 fuzzy environment is introduced. Then the evacuation strategy selection model and the calculation steps for metro station in emergency situation are constructed. Finally, a numerical example about the evacuation strategy selection along with a sensitivity analysis about the parameters and a comparison analysis with Chen's research is provided to verify the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract Evacuation process under limited visibility is different from that under good visibility. To investigate the evacuation efficiency under limited visibility, different evacuation strategies including walking along the wall (S 1), following the average movement direction (S 2) and following the average position (S 3) are proposed in this paper. Performances of these strategies under different visibilities, densities and exit widths are compared based on a revised social force model. Simulation results show that strategy S 1 is more effective at low densities while strategy S 2 and S 3 are more efficient at high densities. It is noted that strategy S 2 outperforms S 3 under the same condition. In addition, strategy S 1 is not sensitive to the change of exit width due to the movement mode of walking along the wall, while the following strategies (S 2 and S 3) have a better performance under the wide exit condition. The evacuation time for different proportions of pedestrians adopting one strategy in the mixed strategy situation is investigated and the optimal mixture proportion is also discussed. This study provides a new insight into the effect of different evacuation strategies on pedestrian evacuation, which is helpful for evacuees or organizers of public events to make an efficient evacuation plan under limited visibility. Highlights • A revised social force model is introduced in this study. • Different evacuation strategies under limited visibility are proposed. • Performances of different strategies are compared by simulation. [ABSTRACT FROM AUTHOR]

This study considers an evacuation problem where an evacuee tries to escape to the boundary of a convex affected area on a grid network. The boundary is unknown to the evacuee and cannot be identified until reaching an arbitrary point of it. We propose an online evacuation strategy with a competitive ratio less than 17.5, which improves the previously best result of 19.5. [ABSTRACT FROM AUTHOR]

The fire ignited due to air conditioner (A/C) malfunctioning is studied numerically for a single room, two rooms with interconnection, two interconnected rooms with attached corridor and a two-storeyed building with stairs. Coupled finite difference and finite volume based open source solver, Fire Dynamics Simulator (FDS) is used for domain discretization and solution of governing equations. Heat release rate per unit area (HRRPUA) is varied in the single room case and temperature and visibility contours are studied to determine HRRPUA corresponding to maximum hazard, judged based on available safe evacuation time (ASET) calculation. Further, positions of air conditioners, at a prescribed HRRPUA, are varied in two interconnected rooms to obtain the case with maximum ASET. Evacuation strategy is discussed and the maximum number of persons who can be safely evacuated from the accident site is calculated followed by the variation in the position of doors in the case with inter-connected doors attached with a corridor. Soot flow pattern and flame contours are also observed for each of the above cases. At the end, fire breakout is simulated in a two-storeyed building with stairs and having the room configuration based on the maximum ASET value. [ABSTRACT FROM AUTHOR]

This study considers an evacuation problem where the evacuees try to escape to the boundary of an affected area, which is convex, and a grid network is embedded in the area. The boundary is unknown to the evacuees and we propose an online evacuation strategy based on the Fibonacci sequence. This strategy is proved to have a competitive ratio of 19.5, which is better than the best previously reported result of 21. [ABSTRACT FROM AUTHOR]

In emergencies, evacuations move pedestrians to safety. Extensive research has investigated strategies that can improve evacuation efficiency of pedestrian crowds in various contexts. However, most of this research considers pedestrians as homogeneous agents and the question of how vulnerable pedestrians can be supported in evacuations has not been convincingly resolved. Here, we focus not only on pedestrians with the same characteristics but also on vulnerable pedestrians defined by moving at a lower speed or being located further away from exits. We investigate strategies for helping these vulnerable pedestrians in three evacuation stages: the pre-evacuation stage where vulnerable pedestrians can respond to incidents quickly, the response stage where vulnerable pedestrians can be preferentially assigned to exits in the case of limited exit resources, and the evacuation phase where we place an obstacle in front of the exit. Our simulation results indicate that the effectiveness of these strategies depends on crowd characteristics and contexts (e.g., crowd size and pedestrian initial distribution), and different strategies may have other consequences, such as making pedestrians experience a higher accumulated force or walk longer distances. We found that only in some cases machine learning methods including kernel naïve Bayes and Linear SVM can predict which strategy will work best based on the initial distribution of pedestrians, suggesting that at least sometimes it may be possible to select strategies based on observed conditions. Our work highlights the importance of context and heterogeneous populations when developing strategies for evacuations and may thus be helpful for crowd safety and evacuation management. [ABSTRACT FROM AUTHOR]

We consider the problem of evacuating some people from an unknown convex region. The people do neither have information about the region boundary nor their positions. We seek competitive strategy that achieves a competitive ratio of the evacuation path over the shortest path. In the scenario of general plane, we propose a strategy SOP for one group, and prove that its competitive ratio is 19.64. And we propose a 14.37-competitive strategy STP for two groups. Also, we present efficient strategies in the scenario of grid network. Furthermore, our strategies can be used for guiding the robot to search the boundary of an unknown region. [ABSTRACT FROM AUTHOR]

The egress strategy in high-rise buildings has traditionally been based on the sole use of stairs for evacuation. However, it is becoming more common to include evacuation elevators in the egress strategy in high-rise buildings. Traditionally, evacuation elevators have not been allowed as an evacuation route, and people have been instructed to not use elevators in case of fire. This means that people might still not consider evacuation elevators even if they are designed to be safe in case of fire. Even if people choose evacuation elevators, they might not be willing to wait very long for an elevator to arrive. Virtual reality (VR) experiments were conducted to study exit choice and the waiting time for evacuation elevators in high-rise buildings. The experiment was performed in a VR lab with a VR model of an existing high-rise building. Results suggest that a simple way-finding system using green flashing lights can influence people to more likely choose the elevator as their first evacuation choice. The results also show that the general trend is that people wait for either a limited time (<5 min) or a long time (>20 min). Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]