Table of Content

    28 April 2022, Volume 32 Issue 4
    Safety social science and safety management
    Scenario deduction and analysis for spillover risks of international sports events under influence of COVID-19
    FANG Danhui, XU Simin, XU Hongqian, XU Miao, HU Ziyao, ZHOU Min
    2022, 32(4):  1-7.  doi:10.16265/j.cnki.issn1003-3033.2022.04.001
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    In order to improve risk prevention and control capabilities for international sports events under the background of COVID-19, case data of 23 international sports since the pandemic outbreak were collected, and an evolutionary network model with COVID-19 as risk source was established. Then, risk analysis on the model was carried out based on in-and-out degree, number of sub-net nodes, the shortest path and average path of complex network theory, key risk event nodes were identified, and preventive measures were put forward. Finally, critical chains were obtained by analyzing causal mechanism and types of risk chains, and countermeasures and suggestions for chain disconnection and disaster mitigation were put forward. The results show that severe epidemic situation and rising risk of virus transmission in host cities are the key nodes in evolutionary network, and cycle chain of political relations and public opinion is the most destructive one. Therefore, it is necessary to promote the development of a public opinion monitoring system and strengthen positive publicity of sports events.
    Sub-safety state identification of ATC under multi-factor coupling of vulnerability
    YUE Rentian, ZHANG Zhibo
    2022, 32(4):  8-14.  doi:10.16265/j.cnki.issn1003-3033.2022.04.002
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    In order to effectively prevent and control aviation accidents and unsafe events caused by ATC, the sub-safety state of ATC operation was scientifically and accurately identified. Firstly, based on vulnerability theory, the concept of ATC operation system vulnerability was obtained. Secondly, the coupling model of vulnerability factors was constructed to analyze the change characteristics of system operation state in the evolution process of characteristic factors, and the essence of sub-safety state was analyzed referring to immunology theory. Finally, N-K model was used to calculate coupling values of different vulnerability factors as boundary set of characteristic elements, and the cloud model reverse cloud generator is used to evaluate the boundary of characteristic elements. All vulnerability factors are integrated, and the final operation state of the system is verified. The results show that the exposure degree of two-factor coupling system is 0.094 9, and deviation of system operation state from 0.077 6, the recovery of system state from 0.057 0, and final state of the system is 0.962 1. Three-factor couplings are 0.341 7, 0.308 4, 0.201 5, 0.859 9, respectively, and four-factor couplings 0.861 0, 0.877 9, 0.541 7, 0.663 8,which are basically consistent with verification results. Sub-safety state occurs in the stage of system exposure greater than sensitivity, and the evolution process of system vulnerability is exposure-fitness-sensitivity-fitness.
    Dynamic visual characteristics and load of drivers during overtaking maneuvers on prairie highways
    LYU Zhen, QI Chunhua, ZHU Shoulin
    2022, 32(4):  15-22.  doi:10.16265/j.cnki.issn1003-3033.2022.04.003
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    In order to explore the visual perception and load characteristics of drivers in the process of overtaking on prairie highways, a driving test was carried out on typical prairie secondary roads. Drivers' eye movement data were collected, and change characteristics and load difference of typical eye movement indexes during free driving and overtaking vehicles of different types were analyzed and compared. The results show that the gaze duration, gaze rate, and saccade frequency of drivers during overtaking are significantly greater than free driving, and there is difference between vehicle types. The gaze point range is concentrated during overtaking, and gaze shift mode is fixed. For the case of overtaking a small vehicle, the probability of drivers' gaze point shifting between road ahead and the rear side mirror is greater than that of a large vehicle. The blinking time of drivers during overtaking is significantly lower than that of free driving. All these indicate that instantaneous increase in demand for driving tasks during overtaking leads to sudden changes in drivers' gaze characteristics and a significant increase in mental load.
    Formation mechanism of safety accidents in domestic drifting tourism based on GT
    FANG Xue, XIE Chaowu, HUANG Rui
    2022, 32(4):  23-29.  doi:10.16265/j.cnki.issn1003-3033.2022.04.004
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    In order to explore formation mechanism of accidents in drifting tourism, 932 cases of such accidents from 2010 to 2019 were analyzed through open coding, main axis coding and selective coding based on GT. The results show that the accident risks cover 4 core categories, namely human, equipment,environment and management risks, and 13 main categories, including tourists' poor physical fitness, staff'slack of expertise, substandard equipment, bad weather, ineffective rescue and treatment. Drifting activities are affected by interaction of multiple risks at various stages. The danger is laid in preparation stage, accidents outbreak during experience stage and continue to spread during termination stage, which leads to more losses.
    Application of ST-GCN in unsafe action identification of construction workers
    LIU Yao, JIAO Shuangjian
    2022, 32(4):  30-35.  doi:10.16265/j.cnki.issn1003-3033.2022.04.005
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    In order to identify unsafe actions of construction workers accurately and timely, a real-time recognition method based on skeleton was proposed by using computer vision, image recognition technology and safety knowledge of buildings. Then, pose estimation algorithm and action recognition algorithm were combined to establish a model, and motion classification and unsafe motion recognition were realized by training the model with comprehensive data. Among them, AlphaPose was used for posture estimation to extract coordinate positions of key points of bones, and ST-GCN was adopted for action recognition. Finally, the model was verified through experiment. The results show that the method's accuracy rate of dangerous actions identification for ladder climbing can reach 98.48%. Meanwhile, ST-GCN has stronger generalization ability compared with support vector machine, random forest and LSTM. This method can improve traditional safety management mode and information application of safety management through real-time identification and early warning of unsafe actions of workers on site.
    Safety engineering technology
    Influence of asperity shapes on friction coefficients of sandstone joints
    WANG Laigui, ZHAO Guochao, LIU Xiangfeng, ZHAO Na, LI Xilin
    2022, 32(4):  36-43.  doi:10.16265/j.cnki.issn1003-3033.2022.04.006
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    In order to analyze influence of asperity shapes on sliding stability of sandstones, a sliding friction test was performed on a self-made device. With asperity shapes of sandstone surface being considered as a regular polygon and asperity shape coefficient being introduced, a prediction model for friction coefficients of sandstone joints, including asperities, was proposed. The results indicate that along with increase in asperity's length, friction coefficients gradually decrease, and their variation range becomes narrower. When the length is constant, friction coefficients gradually decrease with the increase of asperity shape coefficient. And in the case of constant asperity shape coefficient, friction coefficients gradually decrease with increase of length. The predicted friction coefficient is in good agreement with test value when the length is between 2-5 mm.
    Study on dual-objective optimization of dust under airflow regulation in fully mechanized faces
    GONG Xiaoyan, TONG Dandan, FAN Jiangjiang, PENG Gaogao, LI Zhen, ZHAO Shaolong
    2022, 32(4):  44-50.  doi:10.16265/j.cnki.issn1003-3033.2022.04.007
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    In order to solve the problem of heavy dust accumulation in roadways caused by the failure of current ventilation mode in coal mines to dynamically regulate wind state of its air outlets according to actual needs during tunneling process, flow field simulation test method was adopted to analyze and obtain regression data of dust concentration along with changes of air flow parameters of the outlets. Secondly, with the lowest respirable dust concentration at drivers' place and optimal total dust concentration at return side as goals, a dual-objective optimization model of dust concentration under control of airflow was established. Then, it was solved based on particle group algorithm, and ideal solution was selected as optimal airflow control plan. Finally, downhole test and dust reduction effect analysis were carried out using self-developed control device. The results show that after optimal airflow regulation, total dust concentration on return side is reduced by 38.55% and 42.11% when air outlet is 5 and 10 m respectively away from end face, and respirable dust concentration at drivers' place is reduced by 26.05% and 27.29%, thus providing theoretical basis for safe and efficient ventilation and dust reduction in fully mechanized faces.
    Influence of coal rank on CPSD in low-temperature N2 adsorption
    HONG Lin, WANG Wenjing, GAO Dameng, GUO Yingchao, MA Honghai
    2022, 32(4):  51-58.  doi:10.16265/j.cnki.issn1003-3033.2022.04.008
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    In order to study coal adsorption theory and adsorption mechanism of coalbed methane, six coal samples of different ranks were selected for low-temperature N2 adsorption experiments to explore CPSD of filled N2 molecules in coals. Then, experimental isotherm characteristics were analyzed through density functional theory (DFT) and theory of volume filling of micropore (TVFM), and critical filling pressure (CFP) and CPSD for micropore fillings were obtained. Finally, relative pressure segmentation method was used to verify the results by fitting of Langmuir equation-Dubinin-Astakhov (D-A) equation-Brunauer-Emmet-Teller (BET) equation. The results show that N2 adsorption/desorption isotherm of coal samples, from low to high rank, transitions from type II to type I. And proportion of N2 molecules present in forms of micropore filling and monolayer adsorption in low-rank coals is greater than that of high-rank ones. CPSD decreases first and then increases as coal rank goes from low to high. The higher the rank is, the smaller CPSD range of 6 coal samples will be, which is between 1.61-2.19 nm.
    Research on coupling evolution path of gas explosion risks in coal mines
    CHENG Lianhua, GUO A'juan, GUO Huimin, CAO Dongqiang
    2022, 32(4):  59-64.  doi:10.16265/j.cnki.issn1003-3033.2022.04.009
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    In order to reveal evolution process of gas explosion risks in coal mines during accident development, firstly, risk factors were extracted through 5W analysis method by analyzing 289 gas explosion accident investigation reports, and then, they were classified based on interpretation structure model. Secondly, concept of risk coupling strength was defined by adopting Pearson algorithm, and risk coupling was analyzed by SPSS21.0. Finally, risk evolution paths were constructed according to temporal relationship and logical sequence among risk factors.The results show that the coupling intensity of spark generation and illegal firing is the largest for all the past gas explosion accidents. There are 9 strong coupling risk evolution paths, of which 3 are the shortest ones. The three key measures to prevent accidents are to control gas probe shortage, gas leakage detection and blasting flame.
    Transient radiative heat transfer of pool fires based on large eddy simulation
    SUN Yujia
    2022, 32(4):  65-71.  doi:10.16265/j.cnki.issn1003-3033.2022.04.010
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    In order to explore transient radiative heat transfer characteristics of pool fires, a combustion model of methanol fire was developed based on large eddy simulation, and non-gray radiative properties of combustion gases were simulated by adopting accurate weighted sum of gray gases (WSGG) model. Then, transient characteristics of temperature, velocity, species concentration and radiative energy were investigated. The results show that gas temperature varies in a periodical pattern, during which high temperature gases form above pool surface, then rises, expands and spreads in cycles, with its velocity increasing first and then decreasing during rising process. Due to this factor, radiative feedback at surface shows an oscillating behavior, and radiative heat flux at center varies between -17 and -7 kW/m2 drastically, which decreases along radial direction. Moreover, probability density of heat fluxes at surface spreads like a triangle. As the ground is far away from fire and partially blocked by tanks, its heat flux is one order of magnitude smaller that of pool surfaces.
    Multi-objective optimization of normally-open airbag of school buses under mixed conditions
    HONG Liang, LIU Gang, GE Ruhai, LI Liang, LI Siyuan
    2022, 32(4):  72-79.  doi:10.16265/j.cnki.issn1003-3033.2022.04.011
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    In order to improve child occupants' safety on school buses under mixed conditions, protective performance of normally-open airbag was optimized. Firstly, injury thresholds of 6-year-old and 12-year-old children were determined. Secondly, a simulation model of school buses was established and verified by sled test data, and a coupling model of school buses and normally-open airbag was built. Finally, based on different combinations of collision conditions and child ages, six mixed conditions were established. Finally, a response surface proxy model was constructed with airbag's main design parameters as optimization factors and weighted injury criterion as optimization target. The results show that according to improved NSGA-Ⅱ algorithm, the optimal configuration is upper strap length at 0.258 8 m, height of installation position at 0.385 6 m, initial pressure of exhaust at 1.199 6×105 Pa, and its opening degree at 0.98. And under mixed conditions, normally-open airbag with optimal configuration can minimize risk of injuries in child occupants.
    Hazard characteristics of multi-component mixtures from perspective of quantitative risk assessment
    XIN Baoquan, YU Jianliang, DANG Wenyi, BAI Yongzhong,YU Anfeng
    2022, 32(4):  80-85.  doi:10.16265/j.cnki.issn1003-3033.2022.04.012
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    In order to improve prediction accuracy of multi-component mixture risks, hazard characteristics of three typical mixtures of high SNG, liquefied petroleum gas (LPG) and gasoline were studied based on risk theory. ESPD of 17 kinds of scenarios was calculated according to multi-component model theory and mixture characteristics. Then, difference between pure component model and multi-component one in QRA was compared and analyzed, and an optimal simplified risk prediction model for multi-component mixtures was proposed. The results show that for SNG, ESPD of pure component is underestimated by 19.9%-61.4% compared with the multi-component. In the case of LPG, it is underestimated by 13.6%-26.0% to adopt substitution of pure propane, but overestimated by 43.3%-273.5% to adopt "propane + butane" substitution. Moreover, for gasoline, it is overestimated by 2%-9.7% for use of n-hexane, but underestimated by 78.8%-95.3% for that of octane. A method of equating a multi-component mixture to one or more pure substances may significantly underestimate or overestimate risks of mixtures, and it is suggested to adopt a two-component mixed model in risk assessment.
    Research on slip stability and interface shear model of reinforced tailings slope
    JIN Hongsong, YI Fu, QI Xupeng, YU Huize, DU Changbo, YU Ben
    2022, 32(4):  86-92.  doi:10.16265/j.cnki.issn1003-3033.2022.04.013
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    In order to analyze slope-sliding stability of reinforced tailings dams and explore influence of overlying load and tailings water content on initial shear stiffness of reinforced tailings interfaces, direct shear test on such tailings was conducted and a shear model was established by using geosynthetics direct shear pull-out test friction system. Then, initial shear stiffness value was obtained by fitting the test results. The results show that during the test, shear stress will decrease slightly after reaching peak value. The outcomes calculated by new shear model are close to the actual value, and the error of initial shear stiffness is less than 1 kPa, which is better than the conventional model. With the increase of water content, the stiffness first increases to the peak value and then decreases gradually. However, as overlying load increases to a certain value, it will be stable. Moreover, the maximum initial shear stiffness of each group can be obtained, which can judge whether the tailings dam is stable or not.
    Study on asymmetry ratio of Li-ion battery fire smoke
    LI Cong, ZHOU Yong
    2022, 32(4):  93-98.  doi:10.16265/j.cnki.issn1003-3033.2022.04.014
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    In order to avoid false alarm in airplane cargos caused by dust and other aerosols in the air, a fire detection method based on multi-wavelength and multi-observation angle was proposed. Asymmetry ratio (ratio of forward to backward scattered signals) of Li-ion battery fire smoke and nuisance aerosols (ISO 12103-1 A1 dust, ISO 12103-1 A2 dust, Dolomite 90 dust, water mist) was obtained through experiments, and then used to distinguish the fire smoke and the aerosol. The results show that when the wavelength is 405 nm, the asymmetric ratio to distinguish the two is 7.25-10.54, which will be 6.56-6.82 for the wavelength of 870 nm.
    Key cause chains selection of electric personal accidents based on combinatorial association analysis model
    ZHAO Chufan, MI Chuanmin, ZHOU Zhipeng, FANG Jing
    2022, 32(4):  99-106.  doi:10.16265/j.cnki.issn1003-3033.2022.04.015
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    In order to improve security management ability and production safety of power enterprises, with 208 electric personal accidents in China from 2015 to 2019 as samples, their occurrence path and inherent cause law were explored. Firstly, a screening model of key cause chains based on association rule mining and grey association analysis was proposed considering the two methods' defects, namely the former was difficult to determine thresholds and the latter can not find hidden connection of data. Then, empirical analysis was conducted, strong association rules among accident causes were discovered by using association rules, and pairwise causes which could reflect accident paths were selected by increasing threshold of grey relational degree to identify key cause chains. Finally, the similarity between these key chains and accident samples was verified by Jaccard similarity calculation method. The results show that they are highly similar, which meanwhile demonstrates the effectiveness of the proposed model.
    Optimization of scattering angle for fire smoke detectors based on asymmetry ratio
    SHI Zhicheng, ZHOU Yong, CHENG Xudong
    2022, 32(4):  107-112.  doi:10.16265/j.cnki.issn1003-3033.2022.04.016
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    In order to improve performance of smoke detectors based on asymmetric ratio, scattering angle was optimized, and a light scattering physical model was established based on collected particle size information of fire smoke. Then, angular distribution of scattered light intensity was calculated with a certain particle size distribution by using DDA method, and influence of particle morphology and size parameter on scattering characteristics was discussed. The results show that scattered light intensity decreases first and then rises as observation angle increases, and the angle corresponding to the minimum intensity value changes withe size parameter. The key to optimize scattering angle design of smoke detectors based on asymmetry ratio lies in the selection of back-scattering angle which should be 110° when size parameter is small and 135° when the parameter is large.
    Experimental study on influence factors of CH4 displacement by CO2
    JIANG Yanhang, BAI Gang, ZHOU Xihua, WANG Siqi, WANG Lianhua, FAN Chaojun
    2022, 32(4):  113-121.  doi:10.16265/j.cnki.issn1003-3033.2022.04.017
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    In order to study influence of multi-factor coupling on CH4 production and CO2 sequestration effect in the process of CH4 displacement by CO2, displacement experiment was carried out under conditions of different gas injection temperature(θ), pressure (P) and water content of coal samples (W). Variation characteristics of CH4 output rate (η) and CO2 storage rate (ξ) under different conditions were researched and analyzed. Then, η and ξ quadratic regression response surface models were built based on response surface methodology, separate influence of gas injection temperature (A), gas injection pressure (B) and moisture content (C) on η and ξ and interaction between each factor were investigated. The results show that η increases along with increase of θ and P, while decreases with that of W. ξ increases with increase of P, while decreases with that of θ and W. Among all influencing factors, A, B, and C are significant terms of η, B and C are those of ξ, and influence degree of primary term on η and ξ is C>B>A. That of interaction term on η is: BC>AC>AB, and the interaction between AC and BC is significant, while AB interaction is not. Influence degree of interaction term on ξ is AB>AC>BC, and interaction between AB and AC is extremely significant, while that between BC is not. The average deviations between experimental values outside coding interval of η and ξ of the 4 groups and predicted values of the model are 3.64% and 2.605%, respectively.
    Prediction of death toll in coal mine accidents based on optimized Markov model
    TANG Fei, WANG Yungang, DU Bingcheng, KONG Xiangyan
    2022, 32(4):  122-128.  doi:10.16265/j.cnki.issn1003-3033.2022.04.018
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    In order to accurately predict death toll in coal mine accidents, applicability of three prediction models was analyzed, including grey model, renewal grey model and unbiased grey model. Firstly, their prediction accuracy was analyzed by adopting posterior residual ratio, mean relative error and small error probability.Then, optimized grey model prediction results was revised with Markov model. Finally,death number of coal mine accidents from 2020 to 2022 was predicted.The results show that the interval selection of original data has a great influence on prediction accuracy, so these with better accuracy should be selected as much as possible. The unbiased grey model proves to be the best one by comparing and analyzing prediction accuracy of all three models. The unbiased grey Markov model can not only eliminate inherent deviation of grey model, but also improve prediction accuracy with an average accuracy of 93.8%.
    Influence mechanism of gas pressure reduction on coal deformation and seepage
    WU Xuehai, LI Bobo, GAO Zheng, XU Jiang, FU Jiale
    2022, 32(4):  129-134.  doi:10.16265/j.cnki.issn1003-3033.2022.04.019
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    In order to study coal deformation and gas seepage behaviors caused by pressure reduction in gas extraction process, based on seepage test and triaxial compression test of gas pressure reduction, coal deformation and seepage characteristics were obtained. Then, matrix shrinkage deformation was modified by considering adsorption damage, and a permeability model was constructed before its rationality was verified by experimental results. The results show that with the decrease of gas pressure, coal permeability presents a "V" shaped change trend. The axial and radial deformation increase linearly, and coals injected with CO2 produce larger deformation than that with CH4, with radial deformation being 1.89 times of axial deformation. Moreover, the elastic modulus and peak principal stress difference in coal with CO2 are lower to different extent than those with CH4.In order to ensure safe production, attention should be paid to the issue of coal strength reduction caused by CO2 injection into coal seam when using CO2 displacement or CO2 fracturing anti-reflection technology.
    Rapid construction mode of emergency material supply chain
    LIANG Jinfan, ZHAO Hanping, ZHANG Jiale
    2022, 32(4):  135-140.  doi:10.16265/j.cnki.issn1003-3033.2022.04.020
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    In order to improve response effeiciency to various public emergencies in China, firstly, characteristics of emergency materials were summarized, and definition and structural features of emergency material supply chain were clarified. Secondly, multi-level supply and demand information, such as government reserve information, social enterprise information and social media information, was integrated and processed before it was updated quickly and dynamically. Then, such information was shared, and a material scheduling platform was built for efficient allocation. Finally, based on scientific and sufficient flow of information and materials, rapid construction mode of emergency material supply chain was integrated and summarized. The results show that this supply chain is dedicated to changing emergency management from traditional government-promoted and government-executed mode to government-supervised, data-promoted and market-executed one, shortening material supply time overall and strengthening stability and controllability of material logisitcs.
    Public safety
    Research on risk perception tendency of drivers based on multi-class Adaboost algorithm
    QIN Yaqin, LI Qiugu, ZHAO Pengyan, BAO Fawang, XIE Jiming
    2022, 32(4):  141-147.  doi:10.16265/j.cnki.issn1003-3033.2022.04.021
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    In order to prevent and reduce road traffic accidents, multi-class Adaboost SAMME algorithm was applied to identify risk perception tendency of different drivers. Firstly, perception utility of 56 drivers was quantified based on traffic conflict analysis method. Then, drivers' behavior characterization parameters in 6 risky situations were obtained through KMRTDS driving simulator. Finally, linear discriminant analysis (LDA) and Adaboost SAMME algorithm were employed to gradually construct a classification and prediction model for drivers' risk perception tendency based on driving behavior data, and k-fold cross-validation method was adopted to evaluate the model's effectiveness. The results show that the accuracy of proposed model is up to 92.9%, and it can effectively identify risk perception tendency of different drivers which are divided into three risk perception types, namely safe type, radical type, and compound type.
    Cellular automata model for emergency evacuation considering panic factor
    FENG Sihai, WANG Zhijie, DENG Jie, XIN Yaojiao, HE Yuanhua
    2022, 32(4):  148-154.  doi:10.16265/j.cnki.issn1003-3033.2022.04.022
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    In order to clarify influence of panic on evacuation process, contagion of panic emotion in evacuation crowd was simulated by using a method that combined cellular automata evacuation model and emotional contagion model based on thermodynamics. With consideration given to the individual difference of evacuees and dangerous environment, evacuation process of crowd in different environment was simulated by quantifying panic emotion values and integrating them into evacuation decision of pedestrians. The results show that panic emotion mainly affects pedestrians near dangerous area and its influence scope will expand along with its contagion, thus decreasing overall evacuation efficiency. Compared with the model which doesn't consider panic factor, for the proposed model, panic will prolong evacuation time in the case of low initial population density, but when the density increases to a certain extent, evacuation time will no longer be prolonged while more people will be trapped. Increasing diffusion speed of risk areas will speed up spread of panic, causing earlier occurrence of large-scale panic crowd.
    Dynamic fire risk indexes for stadiums from perspective of big data
    LU Ying, ZHAO Zhipan, JIANG Xuepeng, WU Jindong, FAN Xiaopeng
    2022, 32(4):  155-162.  doi:10.16265/j.cnki.issn1003-3033.2022.04.023
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    In order to solve problems that static indicators are more frequently used in fire risk assessment of stadiums, while dynamic indicators are not clear, and internet of things monitoring data required for dynamic assessment is diverse and complex, characteristics of 48 kinds of internet of things monitoring data such as fire host and fire tank liquid level were analyzed, and a quantifiable dynamic index system was constructed, including fault location percentage of fire hosts and difference between actual and standard liquid level. Then, an data set based on monitoring data of 27 stadiums was established, 48 indicators were screened and optimized using random forest algorithm, and development and optimization of dynamic fire risk assessment indicators were studied. The results show that when the 9-dimensional features with the lowest importance are deleted, mean square error reaches the minimum of 0.05, and optimal dynamic fire risk assessment index system for stadiums is obtained.
    Analysis on cause factors and evolution paths of fire accidents in buildings
    GUAN Cheng,ZHANG Zhizhen,LI Jing,WU Bin,YAN Qihang
    2022, 32(4):  163-170.  doi:10.16265/j.cnki.issn1003-3033.2022.04.024
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    In order to effectively prevent and reduce fire accidents in buildings, 58 of such accidents were collected based on 24 Model, and individual and organizational factors leading to their frequent occurrence and evolution paths were analyzed. Then, an evolution path diagram was developed. The results show that among all direct causes, the more frequent ones are violation of rules and regulations by individuals, supervision responsibility not in place and failure of production site design to meet requirements of emergency evacuation. And indirect causes include problems in safety knowledge, consciousness and habits of accident parties and organization managers, with a frequency of 75.86%, 84.48% and 56.90% respectively. In terms of fundamental causes, lacks of safety production responsibility system, fire hazard investigation and management system and safety training system all feature a frequency of over 85%, while for root causes, the most frequent ones are relatively low importance of safety and inadequate understanding of main responsibilities for production safety.
    Technology and engineering of disaster prevention and mitigation
    Generation of typhoon emergency response plan based on FastDTW case retrieval
    CHEN Liting, ZHENG Jing, GAO Jianqing, LIANG Juan
    2022, 32(4):  171-176.  doi:10.16265/j.cnki.issn1003-3033.2022.04.025
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    In order to improve efficiency of typhoon case retrieval method, spatio-temporal nature of typhoon hazards and importance differences regarding case attributes and information integrity were studied. Spatio-temporal trajectory similarities were measured using FastDTW algorithm, and a set of historical cases similar to target typhoon path was established. To highlight importance differences between case attributes, an optimized model of CCSD method was used to determine attribute weights. Subsequently, case similarity was obtained by aggregating that of attributes. Then, considering spatio-temporal trajectory similarities and case similarities based on disaster information, the most similar case was retrieved from the set of historical cases, and an emergency plan regarding target typhoon trajectory was generated. Finally, the method was applied to real examples. The results show that the proposed method retrieves the most similar historical case by measuring spatio-temporal trajectory similarities of typhoons, determining attribute weights and synthesizing resulting information to ensure that the generated emergency plan is comprehensive and accurate with respect to the target typhoon.
    Flood inundation area extraction method of SAR images based on deep learning
    GUO Wei, YUAN Hongyong, XUE Ming, WEI Pingyan
    2022, 32(4):  177-184.  doi:10.16265/j.cnki.issn1003-3033.2022.04.026
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    In order to improve decision-making ability for flood disaster emergency rescue and quickly extract flood inundation areas, an extraction method of SAR images based on deep learning was proposed. Firstly, flood inundation area extraction model of SAR images was established based on DeepLab v3+ model. Then, considering difficulty in obtaining labeled samples of SAR images, a semi-automatic sample making method based on optical image water index was proposed, which greatly reduced the labor and time required for annotation. Lastly, Sentinel-1 images were used for experimental analysis to verify the model's accuracy. The results show that the proposed extraction model has strong adaptability to complex surfaces. Compared with the adaptive threshold method, it features higher recognition accuracy, and better recognition effect of water edge, small area water body and thin and long linear water body in remote sensing image, with an mean Intersection over Union of 0.83.
    Emergency technology and management
    Location and routing of dangerous goods' storage and transportation under continuous time-varying risks
    KUANG Yujie, ZHAO Jiahong
    2022, 32(4):  185-191.  doi:10.16265/j.cnki.issn1003-3033.2022.04.027
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    In order to improve safety of dangerous goods' storage and transportation, considering the location and routing problems under continuous time-varying risks, warehouse location, transportation routes and flow allocation were optimized simultaneously. Firstly, a nonlinear assessment model for continuous time-varying risks was formulated considering continuous influence of emergency rescues. Then, with minimization of total risks and cost as optimized goals, a multi-objective nonlinear 0-1 mixed integer programming model was developed based on locally connected urban network. Finally, TOPSIS-based Dijkstra phased solution algorithm was designed according to the model's complexity, and several examples were used to verify the effectiveness of the model and algorithm. The results show that compared with current management schemes, the proposed method, which considers continuous time-varying risks, can reduce 48.79% of risks, and therefore provides a better plan for dangerous goods' storage and transportation.
    Occupational health
    Fatigue assessment method of controllers based on CFF
    SUN Ruishan, CHEN Yi, SUN Libin
    2022, 32(4):  192-197.  doi:10.16265/j.cnki.issn1003-3033.2022.04.028
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    In order to monitor fatigue risks of air traffic controllers during their duties, with their CFF as an index to evaluate fatigue degree, a relationship equation between fatigue degree and CFF was established based on KSS scale score. Then, fatigue indexes were defined to reflect fatigue state, and a fatigue evaluation method based on CFF value was established. Finally, through a 36-hour simulated control experiment under state of sleep deprivation, CFF and simulated control scores of five subjects were collected, and relationship between the indexes and simulated control scores was analyzed. The results show that the fatigue index of four subjects change periodically, while that of the other one decrease first and then increase all the time. And there is a negative correlation between fatigue index of each subject and their simulated control performance. With the progress of sleep deprivation experiment, the indexes of five subjects present an upward trend, while the simulated performance shows a downward trend.
    Response characteristics of lifting operation driven by visual information
    JIN Lianghai, WANG Licheng, CHEN Yun, WU Zhipeng
    2022, 32(4):  198-204.  doi:10.16265/j.cnki.issn1003-3033.2022.04.029
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    In order to improve safety of lifting operation, optimal visual field cone and maximum visual field cone were analyzed considering visual angle and visual distance, and driving level of visual information on lifting operation was measured from the angle of geometric optics. Then, with lifting drivers as subjects, a virtual test scene was constructed according to operation tasks, visual cognition parameters were collected by using eye movement tracking technology, and eye movement measurement experiment of visual information driving level was designed. Finally, Work Breakdown Structure (WBS) and kinetic element analysis method were used to develop act therbligs coding system, and driving effects of visual information on lifting operation rate and error were studied. The results show that the higher driving level is, the faster lifting operation will be, and there is a strong exponential relationship between them. The driving level with correct operation behavior is generally higher than that with wrong behavior, namely, it is not easy to have wrong operation when driving level of visual information is high.