A BIM-based visualization and warning system for fire rescue

Structural fires are common disasters. In Taiwan, about 100 firefighters die during fire rescues each year, primarily because they are unaware of the causes of the fire and unfamiliar with the location’s environment. Meanwhile, evacuees often die in the panic of evacuation. To solve these problems, this research proposes a Building Information Modeling (BIM)-based visualization and warning system for fire rescue. A fire dynamics simulator (FDS) simulates various conditions of structural fires in conjunction with the visualization and integration properties of BIM, and the simulation results for temperature, carbon monoxide, and visibility can be integrated and presented in the BIM model for briefing purposes before rescue operations begin. In addition, this research integrates Internet of Things (IoT) technology, which allows real-time situation monitoring. In the event of a fire, the BIM model will immediately display the situation of the fire scene and control LED escape route pointers according to the actual situation. The primary objective of this system is to provide useful information to firefighters such that they can be aware of the fire’s environment and create an effective rescue plan. Moreover, the automated LED escape route pointer may assist the building’s occupants to escape, provide the firefighters with valuable information, and allow them quickly to discover hazards so that the number of casualties can be minimized.     

Way-finding during a fire emergency: an experimental study in a virtual environment

The way-finding behaviour and response during a fire emergency in a virtual environment (VE) was experimentally investigated. Forty participants, divided into two groups, were required to find the emergency exit as soon as possible in a virtual hotel building because of a fire escape demand under condition 1 (VE without virtual fire, control group) and condition 2 (VE with virtual fire, treatment group). Compared to the control group, the treatment group induced significantly higher skin conductivity and heart rate, experienced more stress, took longer time to notice the evacuation signs, had quicker visual search and had a longer escape time to find the exit. These results indicated that the treatment condition induced higher physiological and psychological stress, and had influenced the escape behaviour compared to the control group. In practice, fire evacuation education and fire evacuation system design should consider the response characteristics in a fire emergency.     

Behavioral,data-driven,agent-based evacuation simulation for building safety design using machine learning and discrete choice models

To improve occupant safety during building emergencies, evacuation simulations have been widely used for building safety design. Since occupant behavior is a determining factor for the outcome of building emergencies, accurately capturing how occupants make decisions and integrating occupants’ decision-making processes in evacuation simulations is important. In this study, based on the results of fire evacuation experiments in a virtual metro station, how different social (crowd flow) and environmental (visual access and vertical movement) factors would affect individuals’ wayfinding behavior was predicted using machine learning and discrete choice models. The trained models were further employed in agent-based evacuation simulations to examine crowd evacuation performance under different building design scenarios. Both the machine learning and discrete choice models could accurately predict individuals’ directional choices during emergency evacuations. Different building attributes could collectively influence occupant behavior, leading to distinct exit choices and evacuation times. While both the trained machine learning and discrete choice models generated similar results, the discrete choice model had better interpretability. Moreover, by comparing the trained models in this study with a model developed in a prior study, it was found that agents had significantly distinct responses to different building designs. Critical factors (e.g., type and size of buildings, occupants’ familiarity with the building) for the applicability of evacuation models were identified. Furthermore, recommendations were provided for future research that aims at employing evacuation simulations for building design evaluation and optimization.     

公路隧道火灾通风数值模拟分析及逃生研究

利用数值模拟技术和pyrosim软件,对火灾功率为20 MW的中型规模隧道火灾进行了仿真,通过对火灾烟流蔓延模拟结果的分析,得出了该火灾规模的临界风速,并在临界风速下,通过对隧道内的温度、CO浓度的分布进行了数值模拟分析,得出了其分布规律。然后以修正后的克拉尼公式及FED窒息模型作为火灾时人员逃生的判定条件,综合考虑了火灾时隧道各断面温度和CO浓度分别与人员极限忍受时间的关系,最后得出隧道火灾时人员的安全逃生方向及火源下游人员的最大安全逃生时间和最远逃生区域。     

The impact of consumer preferences on the accuracy of collaborative filtering recommender systems

Despite the omnipresent use of recommender systems in electronic markets, previous research has not analyzed how consumer preferences affect the accuracy of recommender systems. Markets, however, are characterized by a certain structure of consumers’ preferences. Consequently, it is not known in which markets recommender systems perform well. In this paper, we introduce a microeconomic model that allows a systematical analysis of different structures of consumers’ preferences. We develop a model-specific metric to measure the recommendation accuracy. We employ our model in a simulation to evaluate the impact of the structure of the consumers’ preferences on the accuracy of a popular collaborative filtering algorithm. Our study shows that recommendation accuracy is significantly affected by the similarity and number of consumer types and the distribution of consumers. The investigation reveals that in certain markets even random product recommendations outperform the collaborative filtering algorithm.     

基于健康度的虚拟火灾逃生行为控制研究

虚拟角色的行为控制是虚拟火灾逃生系统的重要组成部分。在逃生过程中，火灾环境中的各种危害因素会对逃生人员的身体健康产生严重影响，而健康状况又会对逃生人员的逃生行为和速度产生重要影响。为了使虚拟角色的行为控制更加符合这一实际情况，引入了健康度的概念，分析了火灾环境中热辐射、温度、有毒烟气、“贫氧”状况等主要因素对健康状况的影响，以及健康状况对逃生行为的影响，建立了基于健康度的虚拟火灾逃生行为控制模型。实验结果表明，该模型能较真实地模拟火灾逃生行为，有效地提高了虚拟火灾逃生训练的真实感。     

基于Arduino和IOT的家庭消防逃生报警系统

家庭安全一直是人们所关注的问题,但近五年来,每年家庭火灾的次数占总火灾发生次数的50%以上,亡人比例大幅上升。随着人们生活水平的提高,人们的安全意识逐渐加强,对家庭防火安全指数提出了更高的要求。而传统家庭消防逃生报警系统无法实现无线互联、自适应环境生成个性化探测指标并及时通知其他人并报警。为了解决这一问题,以Arduino作为核心控制器,采取物联网和传感器技术,将ESP8266模块与相关的硬件电路进行无线连接,通过APP获取室内实时监测的数据、火灾报警、远程开锁等。这种系统主要运用物联网技术,通过MQTT协议实现信号无线实时传输,弥补了传统系统的不足,能在第一时间联系到干系人,实现预警和协助逃生的目的。     

多速率Ad hoc网络MAC层公平性的分析与改进

在多速率Ad hoc网络中,利用自适应速率调整算法,网络节点可以根据信道质量选择不同的传输速率,从而提高网络的总体通信能力。对多速率Ad hoc网络MAC层公平性进行了仿真和分析,实验结果表明基于IEEE 802.11的多速率Ad hoc网络中存在严重的公平性问题。通过对吞吐率公平和时间公平的讨论,指出在多速率Ad hoc网络中进行MAC层公平性研究,时间公平性标准是较优的选择。另外提出一种针对多速率Ad hoc网络的改进公平回退（EFB）算法,仿真实验的结果表明该算法能够明显提高多速率Ad hoc网络的MAC层公平性。     

Information diffusion-based spatio-temporal risk analysis of grassland fire disaster in northern China

This study presents a Geographical Information Systems (GIS) and information diffusion-based methodology for spatio-temporal risk analysis of grassland fire disaster to livestock production in the grassland area of the northern China. We employed information matrix to analyze and to quantify fuzzy relationship between the number of annual severe grassland fire disasters and annual burned area. We also evaluated the consequences of grassland fire disaster between 1991 and 2006 based on historical data from 12 northern China provinces. The results show that the probabilities of annual grassland fire disasters and annual damage rates on different levels increase gradually from southwest to northeast across the northern China. The annual burned area can be predicted effectively using the number of annual severe grassland fire disasters. The result shows reliability as tested by two-tailed Pearson correlation coefficient. This study contributes a reference in decision making for prevention of grassland fire disaster and for stockbreeding sustainable development planning. The fuzzy relationship could provide information to make compensation plan for the disaster affected area.     

Genetic algorithms optimized fuzzy controller for the indoor environmental management in buildings implemented using PLC and local operating networks

In this paper, an optimized fuzzy controller is presented for the control of the environmental parameters at the building zone level. The occupants’ preferences are monitored via a smart card unit. Genetic algorithm optimization techniques are applied to shift properly the membership functions of the fuzzy controller in order to satisfy the occupants’ preferences while minimizing energy consumption. The implementation of the system integrates a smart card unit, sensors, actuators, interfaces, a programmable logic controller (PLC), local operating network (LON) modules and devices, and a central PC which monitors the performance of the system. The communication of the PLC with the smart card unit is performed using an RS 485 port, while the PLC-PC communication is performed via the LON network. The integrated system is installed and tested in the building of the Laboratory of Electronics of the Technical University of Crete.     

A BIM-based simulation framework for fire safety management and investigation of the critical factors affecting human evacuation performance

Fire hazards are a big threat to human life and property safety. The U.S. fire statistics reveal that, in 2017 alone, 1,319,500 fires caused 3400 deaths and 14,670 injuries, which resulted in a loss of $23 billion [1]. Effective evacuation planning in densely occupied buildings should be primarily put in place if both the number of injuries/fatalities and the level of property loss are to be minimized. However, it is not realistic, and is unethical to study human evacuation performance under a burning building. For this reason, computational tools tend to be the best approach for simulating fire growth as well as human response to fire hazards. This study aims to develop a BIM-based simulation framework that implements the Fire Dynamic Simulator (FDS) and agent-based modeling (ABM) for simulating fire growth and evacuation performance for different building layout scenarios. An experimental implementation is conducted to validate the proposed framework, which verified the benefits of (1) using BIM to offer a platform for conducting simulation design and visualizing the simulation results of (a) hazardous fire zones and (b) effective escape routes; (2) simulating fire growth using the FDS tool; (3) developing an agent-based model that accounts for the critical factors affecting evacuation performance; and (4) applying a statistical analysis for investigating the effects of influential parameters from the proposed model. As a result, the simulation outputs can be used to optimize the building design and to investigate the influential factors on human evacuation efficiency. The proposed framework contributes to building fire safety management by enabling to minimize both injuries/fatalities and property loss.     

Lessons from the evacuation of the world trade centre, 9/11 2001 for the development of computer-based simulations

This paper reviews the state-of-the-art in evacuation simulations. These interactive computer based tools have been developed to help the owners and designers of large public buildings to assess the risks that occupants might face during emergency egress. The development of the Glasgow Evacuation Simulator is used to illustrate the existing generation of tools. This system uses Monte Carlo techniques to control individual and group movements during an evacuation. The end-user can interactively open and block emergency exits at any point. It is also possible to alter the priorities that individuals associate with particular exit routes. A final benefit is that the tool can derive evacuation simulations directly from existing architects, models; this reduces the cost of simulations and creates a more prominent role for these tools in the iterative development of large-scale public buildings. Empirical studies have been used to validate the GES system as a tool to support evacuation training. The development of these tools has been informed by numerous human factors studies and by recent accident investigations. For example the 2003 fire in the Station nightclub in Rhode Island illustrated the way in which most building occupants retrace their steps to an entrance even when there are alternate fire exits. The second half of the paper uses this introduction to criticise the existing state-of-the-art in evacuation simulations. These criticisms are based on a detailed study of the recent findings from the 9/11 Commission (2004). Ten different lessons are identified. Some relate to the need to better understand the role of building management and security systems in controlling egress from public buildings. Others relate to the human factors involved in coordinating distributed groups of emergency personnel who may be physically exhausted by the demands of an evacuation. Arguably, the most important findings centre on the need to model the ingress and egress of emergency personnel from these structures. The previous focus of nearly all-existing simulation tools has been on the evacuation of building occupants rather than on the safety of first responders. Thanks are due to J. Appleby, P. Cooper, A. Foss, S. Hailey and B. Jenks who were responsible for the design and implementation of the GES application. They also drove the development of the Boyd Orr evacuation scenarios that are used to illustrate the opening sections of this paper.     

Risk of fire emergency evacuation in complex construction sites: Integration of 4D-BIM,social force modeling,and fire quantitative risk assessment

Construction industry is claimed to be the fourth most dangerous sector by number of fatalities. In complex construction sites, emergency evacuation risk assessment is a challenging task due to their ever-changing nature. This study developed a model to analyze the risk of fire emergency occurrence, and risks which are associated with evacuation performance (in response to that emergency) through an integrated approach in complex construction sites. To analyze the evacuation scenarios more realistically, we utilized Social Force Model (SFM) simulation engine. Using SFM for simulating the evacuation of complex construction sites has not been adequately addressed in the literature. Microscopically simulating the evacuation scenarios for all workdays of the studied complex project required high computation efforts. To tackle this computation challenge, a parallel computing technique was coupled with SFM simulation engine. More importantly, in this paper site’s evacuation performance was evaluated multi-objectively considering evacuation time and evacuation safety. The construction site’s emergency scenarios were modeled by 4D-BIM, potential for trigger fire emergency was determined by a fire ignition Quantitative Risk Assessment (QRA) module, and site evacuation was simulated by SFM simulation engine. The proposed framework handled the collaboration of 4D-BIM, fire QRA module, and SFM engine. This research study benefited from data driven from a real mega project. The findings demonstrated that analyzing the risk of evacuation through an integrated approach by the proposed model could render more realistic results. The results also provided the project managers with a reliable safety decision-making support.     

Event-driven modeling of elevator assisted evacuation in ultra high-rise buildings

In the past few decades, numerous ultra high-rise buildings have been erected in the metropolitan areas of many cities around the world. For the related building designers, building occupants and the governments, fire safety problem is certainly a major concern, especially after the collapse of World Trade Center in the 9/11 event. That disaster makes people reconsider ultra high-rise building evacuation strategies. Of the current strategies, using elevators in ultra high-rise buildings to assist evacuation seems to be promising in improving evacuation efficiency. To quantitatively evaluate elevator assisted evacuation process, an event-driven agent-based modeling approach is proposed in the present paper. This modeling approach could capture not only the movement characteristics of stair-using occupants but also the detailed elevator motion features. The combined effects of occupants’ and elevators’ parameters on the evacuation efficiency have been investigated. Results indicated that the model is helpful to reveal the dynamics of elevator assisted evacuation, and sometime, using elevators to move all occupants to ground safety point may not be an optimal solution.     

Evaluating the risk of healthcare failure modes using interval 2-tuple hybrid weighted distance measure

Failure mode and effects analysis (FMEA), as a usefulness and powerful risk assessment tool, has been widely utilized in different industries for improving the safety and reliability of systems. However, the conventional risk priority number (RPN) method shows some important weaknesses when applied in actual situations. Moreover, FMEA is a group decision behavior and FMEA team members tend to use different linguistic term sets to express their judgments because of their different backgrounds and preferences, some of which may be imprecise, uncertain and incomplete. In this paper, we propose a new risk priority model using interval 2-tuple hybrid weighted distance (ITHWD) measure to solve the problems and improve the performance of the traditional FMEA. The new model can not only handle the uncertainty and diversity of FMEA team members’ assessment information but also consider the subjective and objective weights of risk factors in the risk ranking process. The model has exact characteristic and can avoid information distortion and loss in the linguistic information processing. Finally, a case study of blood transfusion is provided to demonstrate the effectiveness and benefits of the proposed approach.     

The evaluation of pedestrians’ behavior using <Emphasis Type="Italic">M/G/C/C</Emphasis> analytical,weighted distance and real distance simulation models

M/G/C/C analytical and simulation models have long been used to evaluate the performance of a large and complex topological network. However, such evaluation is only founded on a network’s total arrival rate and its weighted distance. Thus, this paper discusses some concepts and issues in building an M/G/C/C simulation model of a complex geometric system where all its arrival sources and their exact distances to the end of their networks (i.e., corridors) have been taken into consideration in measuring the impacts of various evacuation rates to its throughput, blocking probability, expected service time and expected number of pedestrians. For this purpose, the Dewan Tuanku Syed Putra hall, Universiti Sains Malaysia, Malaysia has been selected as a case study for various evaluations of complex pedestrian flows. These results were analyzed and compared with the results of our analytical and weighted distance simulation models. We then documented the ranges of arrival rates for each of the model where their results exhibited significant discrepancies and suggest ideal rates to best evacuate occupants from the hall. Our model can be utilized by policy makers to recommend suitable actions especially in emergency cases and be modified to build and measure the performance of other real-life complex systems.     

高层火灾智能报警及逃生指导系统

现有高层火灾报警系统因报警滞后,缺乏火灾定位以及逃生引导,导致现场人员伤亡较大。为此,设计了具有精准定位、高效报警以及智能逃生引导功能的火灾警报系统。通过TXW8301-WiFi模块、火灾探测器和语音单片构成节点设备,布控在建筑内各区域,可自动检测火灾发生,并第一时间在各楼层播报火灾位置及具体的逃生指引路线,可以解决高层建筑距离远、隔断多造成因不知情、不清楚逃生路线而错失最佳逃生时机的问题。除自动报警引导功能外,本系统通过对通道监控视频进行去烟补光和去噪处理,并基于深度学习算法进行行人密度检测,可以根据逃生通道的拥堵情况进行多次逃生指导,最终所有信息将在系统总控界面显示,方便统一救援指挥,可最大限度地降低火灾中的人员伤亡。     

煤矿井下避灾模型研究

为了研究井下矿工面对灾害时的避灾情况,利用基于Agent的建模仿真方法在RePast仿真平台上建立了煤矿井下避灾模型,并根据井下矿工的实际情况抽象出了Agent的种类.通过对井下矿工面对灾害时的行为模式进行分析,提取出了Agent在面对灾害时的行为决策.通过将Agent的行为决策进行量化,在仿真平台上对矿工的避灾路线实现了仿真.仿真结果表明：该模型能够实时动态地显示矿工的避灾情况,灾害发生时,利用该模型生成的避灾路线能够提高Agent避灾成功的比例.     

基于Pyrosim对天然气管道泄漏火灾后果的模拟研究

为探究天然气管道泄漏对周围人员和建筑物所造成的影响,提高管道火灾的人员逃生率,采用Pyrosim火灾仿真模拟软件,首先,按照管道火灾的特点设置火源及反应类型,对火灾模拟的过程、热辐射强度范围和温度分布范围进行分析;其次,将火灾模拟时间设为100 s,截取观察15 s、25 s、35 s、45 s、55 s、65 s、7...     

Conditions of emergency lighting

Emergency illumination must be provided in case of power failure in public buildings or places of work. A laboratory study of the mobility of subjects under simulated emergency illumination was performed to determine the level of emergency illumination necessary for a rapid exit, and to establish whether this level depends upon the normal illumination. Both young and elderly subjects were used. The experimental conditions were selected to simulate situations in which the occupants are not familiar with the escape route. In addition to measuring the time that the subjects needed to complete an escape, the subjects were asked to evaluate the lighting on several scales; and their ‘spare mental capacity’ during the escape was measured by their performance on a secondary mental task. The results showed that all measures of performance worsen as the emergency lighting is decreased below 2 Ix. The figure of 2 lx is appropriate for both normal light levels tested, 250 and 1000 lx. Where many elderly people are apt to be present, a minimum of 41x is advisable. These recommendations are higher than those prescribed by the British Standards (0-2 lx) and the Deutsche Industrie Norm (10 lx).