Evacuation Completion Time Research Articles

Sink location problems in dynamic flow grid networks

A dynamic flow network consists of a directed graph, where nodes called sources represent locations of evacuees, and nodes called sinks represent locations of evacuation facilities. Each source and each sink are given supply representing the number of evacuees and demand representing the maximum number of acceptable evacuees, respectively. Each edge is given capacity and transit time. Here, the capacity of an edge bounds the rate at which evacuees can enter the edge per unit time, and the transit time represents the time which evacuees take to travel across the edge. The evacuation completion time is the minimum time at which each evacuee can arrive at one of the evacuation facilities. Given a dynamic flow network without sinks, once sinks are located on some nodes or edges, the evacuation completion time for this sink location is determined. We then consider the problem of locating sinks to minimize the evacuation completion time, called the sink location problem. The problems have been given polynomial-time algorithms only for limited networks such as paths [1–3], cycles [1], and trees [4–6], but no polynomial-time algorithms are known for more complex network classes. In this paper, we prove that the 1-sink location problem can be solved in polynomial-time when an input network is a grid with uniform edge capacity and transit time.

On robustness against evacuees’ unexpected movement in automatic evacuation guiding

The automatic evacuation guiding using mobile devices is a promising disaster-response approach for large-scale disasters. When a disaster occurs, each mobile device recommends a route to a refuge and automatically estimates the state of road segments by comparing the recommended route and observed trajectory. The estimated information is shared among devices using available communication technologies. This scheme assumes that each evacuee follows the recommended route but it might not be satisfied when an evacuee behaves as an outlier taking unexpected movement, which will disturb the normal evacuation. This paper analyzes the effects of outliers and reveals the following characteristics through simulations: The number of passable road segments misestimated as impassable increases with outliers; Many of them, however, can be corrected by passable estimation from other outliers; The remaining misestimation increases the evacuation completion time of 26.5% of normal evacuees by more than 100 s. Since the speedy and accurate outlier detection is difficult in the severe communication environments, this paper alternatively proposes a mechanism that delays to judge a road segment as impassable until gathering the corresponding impassable estimation from M devices. The simulation results show that M=2 achieves a balance between the speediness and safety in evacuation guiding.

출입문 임시폐쇄에 따른 피난시간 변화에 관한 연구

This study analyzed the evacuation time of occupants before and after the temporary closing of the entrance to building among educational research facilities in order to understand time of occupants when the entrance of an existing building is temporarily closed for control purposes. The results are as follows. Firstly, the occupants evacuated through the adjacent door after vertical evacuation using the stairs and the three doors used were adjacent to the stairs before the temporary closing of the door. In particular, it was confirmed that the entrances located at both ends of the building were not used by occupants for evacuation because they were far apart from the stairs. Secondly, after the temporary closing of the door, the occupants start evacuation without recognizing the locked state of the door. As they evacuate again, the time required to complete the evacuation increases and the time required due to restrictions on the available doors is accumulated. Thirdly, it was confirmed that the difference in evacuation completion time between the occupants before and after the temporary closure of the entrance door was about 2.2 times. In particular, the number of evacuees per hour is up to ten simultaneously evacuating at the same time before the temporary closure, but up to three simultaneously evacuating at the same time after the temporary closure. Thus, the number of entrances has a significant impact on evacuation. Lastly, for the convenience of blocking the inflow of COVID-19, creating an electronic list for users and checking temperature, it is necessary to install devices such as “automatic opening and closing of entrances” to ensure the safety of occupants in emergencies such as fires.

Screens surrounding openings in floor slabs of public buildings

Introduction. Screens often surround openings in the floor slabs of atrium buildings to prevent the spread of fire hazards to higher floors and to improve the efficiency of smoke ventilation systems. In this article, the co-authors assess the expediency of installing screens around openings in the floor slabs and identify the best screen height values. In this article, the co-authors perform a quantitative analysis of the ability of screens to prevent the propagation of hazardous fire factors, to identify general regularities typical for a multi-level space, and to develop recommendations for the installation of screens inside public buildings. The co-authors suggest that screen height should be a solution to the following tradeoff problem: the use of screens reduces acceptable evacuation time for the floor that has screens installed and rises the evacuation time for higher floors.Rational screen height selection algorithm. The co-authors propose the following algorithm for the two-stage selection of the rational screen height. At the first stage, the evacuation problem is resolved. As a result, evacuation completion time is determined for emergency exits. Further, acceptable evacuation time and the time needed to block emergency floor exits are identified for a particular type of a fire alarm system.At the second stage, the dynamics of hazardous fire factors in building rooms is assessed for various screen heights. As a result, the rational height of screens is established for the evacuation time to remain positive.Conclusions. Screen height values cannot be determined in advance. Each case requires an individual approach that entails the resolution of evacuation problems and the tracking of the dynamics of hazardous fire factors in buildings that have multi-height spaces. These ideas are in line with the concept of flexible regulation of fire protection systems designated for construction facilities.

Effect of Evacuation Information and Evacuation Behaviors on High-Rise Apartment Residents

As urbanization advances, the number of people living in high-rise buildings is gradually increasing. However, few studies on evacuation planning during emergencies (or simulations) simultaneously considering high-rise buildings and urban areas have been carried out. This study targeted Sejong city in Korea to analyze evacuation behavior in high-rise apartments and the effect of evacuation information. For the disaster situation, this study assumed a worst-case situation in which apartment residents need to quickly evacuate through apartment stairwells and pedestrian roads owing to a major disaster and unexpected accident occurrence. Analysis scenarios were divided by considering the evacuation information level: 1) starting evacuation within 15 min, 2) starting evacuation within 30 min, and 3) starting evacuation within 60 min. Also, scenario 4 is for the case that information for a new optimal shelter location was informed to evacuees, whereas scenario 5 is for the case that information for an existing optimal shelter location was informed to evacuees. The analysis results indicate the evacuation completion time is greatly reduced if high-level information is provided. The results of this study offer guidance on emergency situations using micro-simulations and the Social Force model.

Partitioning Vertical Evacuation Areas in Umeda Underground Mall to Minimize the Evacuation Completion Time

When an underground mall is flooded, the shoppers should be evacuated to a building connected to the mall. However, the number of evacuees from a large-scale underground mall will exceed the capacity of the evacuation center. Furthermore, the evacuation time may be delayed. This paper proposes a mathematical programming problem that minimizes the evacuation completion time on a general planar graph of a partitioned evacuation area with a specified sink capacity. We also propose a workflow for translating the general geometric spatial data to graphical data. The problem is applied to the real spatial data and evacuation setting of Umeda underground mall in Osaka, Japan. The problem’s performance is compared with that of the conventional problem that minimizes the total evacuation distance, and its accuracy is confirmed in a multi-agent simulation. The validity of the proposed method is also discussed.

Proposed evacuation tunnels for wide-area disaster

The present paper proposes a safe evacuation method using underground evacuation tunnels for urban area evacuation owing to a wide-area fire disaster that may occur in the aftermath of a major earthquake. To survey the effectiveness of the evacuation tunnels, evacuation completion time was estimated using wide-area evacuation simulations. It was discovered that evacuation completion time for underground tunnels was one hour faster than that of evacuation above ground (even with the widening of the surface roads) if tunnel usage was appropriately controlled so that vulnerable people (i.e., elderly people and children) used it while others evacuated above ground. Moreover, an estimation of the construction cost of evacuation tunnels in a metropolitan area indicated that one could be built at the same, or even lower, cost than that of the road widening above ground.

Numerical Simulation of Evacuation Process in Malaysia By Using Distinct-Element-Method Based Multi-Agent Model

In Malaysia, not many researches on crowd evacuation simulation had been reported. Hence, the development of numerical crowd evacuation process by taking into account people behavioral patterns and psychological characteristics is crucial in Malaysia. On the other hand, tsunami disaster began to gain attention of Malaysian citizens after the 2004 Indian Ocean Tsunami that need quick evacuation process. In relation to the above circumstances, we have conducted simulations of tsunami evacuation process at the Miami Beach of Penang Island by using Distinct Element Method (DEM)-based crowd behavior simulator. The main objectives are to investigate and reproduce current conditions of evacuation process at the said locations under different hypothetical scenarios for the efficiency study of the evacuation. The sim-1 is initial condition of evacuation planning while sim-2 as improvement of evacuation planning by adding new evacuation area. From the simulation result, sim-2 have a shorter time of evacuation process compared to the sim-1. The evacuation time recuded 53 second. The effect of the additional evacuation place is confirmed from decreasing of the evacuation completion time. Simultaneously, the numerical simulation may be promoted as an effective tool in studying crowd evacuation process.

A Distributed Autonomous Approach to Developing a Disaster Evacuation Assist System

In times of disaster, or other emergency situations, it is essential for people to be evacuated in a smooth manner. Evacuation must be performed promptly and safely. It is necessary to avoid generating a secondary disaster at the time of evacuation. However, this is not easy to realize, because people often tend to panic when faced with disaster, crowding the evacuation passageways of buildings. On the other hand, people do not attempt to evacuate themselves from danger when the normalcy bias has occurred. Therefore, evacuation guidance is very important. However, it is impossible to guide all evacuees through authorities such as disaster countermeasure offices. To deal with this issue, the authors propose a system that provides optimal evacuation guidance autonomously without central server. The system works on the mobile devices of evacuees, performs distributed calculations using the framework of the distributed constraint optimization problem on ad-hoc communication, and does not need a central server. In the experiment using multi-agent simulation, for the case where the evacuees can receive evacuation guidance from this system, the evacuation completion time decreased. This paper presents an overview and the evaluation results of the prototype of the disaster evacuation assistance system.

Agent Based Disaster Evacuation Assistance System

This paper proposes a system that supports people being evacuated effectively from dangerous situations by using multi-agent cooperation. The main feature of this system is that it does not require central servers. The system uses the mobile devices of evacuees (e.g. phones, mobile PCs, tablets) and performs distributed calculations while assessing the locations of evacuees.By using this system, the evacuees are able to know the appropriate evacuation timing. This paper focuses on the formalization of the disaster evacuation problem and how to solve it using the framework of the Distributed Constraint Optimization Problem (DCOP). In order to evaluate this system, an experiment was carried out using multi-agent simulation. The result of the experiment showed that, for the case where the evacuees can receive evacuation guidance from this system, the evacuation completion time for all evacuees (in the case) was about 10% - 30% less than in the case where this system is not used.

Simulating hospital evacuation—the influence of traffic and evacuation time windows

Hospital operators typically do not have the luxury of carrying out a sufficient number of full-scale drills to accurately predict performance (eg, evacuation completion time, time required to evacuate a patient, when to start the evacuation, etc) during evacuation. This research presents a stochastic model via simulation to address an advanced-notice evacuation event such as a hurricane. We employ a simulation-optimization approach, comparing the benefits of additional simulation replications or additional simulation test scenarios in providing statistical accuracy in the results. We then identify the staffing and vehicle transport requirements within a pre-specified evacuation time period while minimizing cost. Moreover, we provide these managers with a modelling framework that can indicate if their current resource set is inadequate to evacuate the patient population within the specified time period. Because the operational costs can be highly variable by facility, we present two alternate cost structures in the analysis. Finally, we consider the effect of varying the evacuation start time on overall cost, as well as evacuation completion. By accounting for competing traffic flow from the mass population evacuation, it would be in the best interest of the hospital to begin their evacuation early, however this is often not an option due to the uncertainty in weather predictions several days prior to hurricane landfall.

A model for allocating resources during hospital evacuations

All hospitals must have an evacuation plan to ensure the safety of patients and prevent the loss of life. However, risk managers typically have not been able to quantify how resource availability, the cost of acquiring those resources, and evacuation completion time are related. This paper proposes a deterministic optimization approach for identifying the staffing and vehicle transport requirements, as well as the scheduling of these requirements, within a pre-specified evacuation time period while minimizing cost. Moreover, we provide these managers with a modeling framework that can indicate if their current resource set is inadequate to evacuate the patient population within the specified time period. We suggest a tailored solution approach that relaxes certain complicating integer constraints in an effort to find feasible, quality solutions. Using this optimization-based heuristic, we then evaluate the hospital evacuation problem, providing insights into the period-by-period requirements of nurses and vehicles, as well as how resource restrictions would affect the evacuation. Finally, we provide a comparison of minimizing cost against minimizing evacuation completion time, where we have a budget restriction in the latter case.

106 火災時のエレベーター利用避難の設計・評価

This paper describes a design and assessment method of fire evacuation plan with elevator. This method has two steps. In the first step, the zone evacuation method is selected as the best evacuation method according to the assessment result of safeness, qualitative evacuation time, and cost. In the second step, escape floors are optimized to make minimize evacuation completion time, which is calculated with combination of the calculation method of stairway evacuation and the elevator capability. These calculation methods are prescribed by government or elevator manufacture association. In the third steps, we evaluate safety with rank-matrix method, and select building safety measures with the evaluation results. The design results for the actual building with this method, shows the evacuation completion time is decreased less than 50% of the time without elevator.

An Examination Of Feasibility Of Elevator Evacuation Based On Risk Assessment

In Japan, occupants should usually escape by stairways, not by elevator cars in case of a building fire. However, it is reported that occupants used elevator cars for evacuation in several major fires such as the Hiroshima Motomachi High-rise Apartments Fire that occurred on October 28, 1996 in Japan. Moreover, the demand for evacuation by elevator cars has been growing especially after the WTC collapse on September 11, 2001. In this context, we developed an elevator evacuation model to simulate evacuation completion time by multiple elevator cars. Moreover, we conducted case studies with this model to examine merits and demerits of evacuation by elevator cars in consideration of the influence of smoke. Main parameters are vertical travel time and waiting time for elevator cars. As a result, we found that elevator evacuation might be more effective than stairways evacuation under certain conditions such as a 57-story high-rise building with 32 elevator cars and 2 stairways based on an existing high-rise building in Japan.