Table of Content

28 May 2024, Volume 34 Issue 5

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Safety science theory and safety system science Safety social science and safety management Safety engineering technology Public safety Emergency technology and management

Safety science theory and safety system science

Study on network security education of college students based on KAP theory

LI Yuanyuan, YUAN Yulin, SUI Lirui

2024, 34(5):  1-8.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1987

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In order to improve the situation of network security education and the quality of network security education in colleges and universities, a cognitive-attitude-behavior theoretical model of college students was constructed. Through the distribution and screening of questionnaires, 659 valid questionnaires were obtained. SEM was used to test the influence of network security education on network security cognition, network security attitude and network security behavior in the collected data. The results show that network security education can have a significant influence on network security cognition, network security attitude and network security behavior. During the influenced process, network security cognition and network security attitude play an independent and chain intermediary role. Legal and moral education, knowledge education, practical activities, and leading by example can directly affect network security behavior. Legal and moral education has the strongest influence, followed by knowledge education. Practical activities and leading by example are the weakest. In terms of specific paths of process, legal and moral education mainly affects network security behavior through direct effect, while knowledge education, practical activities and leading by example mainly affect network security behavior indirectly through security cognition.

Research on talent development systems for emergency technology and management majors to meet national needs

WANG Li, CHEN Wentao, GUAN Wenling, SUN Aijun

2024, 34(5):  9-16.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0128

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To promote the construction of emergency technology and management majors and strengthen the university talent cultivation of emergency rescue, the majors' characteristics were determined based on the national needs in emergency. Then, a talent development mode for emergency technology and management majors was proposed from aspects of professional ethics, theoretical knowledge systems, and practical technical ability. Firstly, the majors' professional ethics were clarified based on the professional ethics requirements from Teaching Standards for Emergency Rescue Technology and National Vocational Skill Standards for Emergency Rescuers. Secondly, a core curriculum system covering the entire emergency lifecycle was proposed using the PPRR(Prevention, Preparation, Response, Recovery) model including prevention, preparation, response, and recovery. Next, a combination of learning and training, integration of government-industries-research organizations was proposed to advance the cultivation of emergency skills and the enhancement of practical innovation capabilities. Finally, a talent cultivation system was developed from the perspectives of textbooks, faculties, teaching process management, a talent assessment system, and a continuous improvement mechanism. The results indicated that the talent development system integrated with public service and social responsibility attributes, full-cycle work content, disasters, and multi-subjects practical applications. Moreover, the system developed a close connection between talent cultivation and practical work needs and guided for cultivating of high-level applied talents in the emergency field who had moral and professional qualifications and theory and practice capabilities.

Safety social science and safety management

Multi-dimensional coupling study on traffic accident risk of highway in mountainous areas

HU Liwei, HE Yu, HOU Zhi, ZHANG Ruijie, CHEN Chen, LIU Bing

2024, 34(5):  17-27.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1497

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In order to effectively reduce the accident rate of mountain highways, the traffic accident data of mountain highways in Yunnan province from 2016 to 2021 was taken as the research object, based on the DEMATEL-AISM. This paper analyzes the causality of risk factors and draws the UP and DOWN directed topological hierarchical diagrams, and finally determines 19 risk factors, constructs an N-K-coupling degree model to quantify the risk factors, couples the risk factors of mountain highway traffic accidents in all dimensions, explores the relationship between risk factors, and proposes a full-dimensional coupling model of traffic accidents in mountainous areas. The results show that in the single dimension, the coupling value of human factors being too close to the vehicle and fatigue driving is 0.741, and the coupling value of road factors is 0.816, which are the two effects that have a greater impact on the system in the single dimension, and the coupling values of human-vehicle and human-road are 0.157 and 0.124 in the two-dimensional. The maximum effect of human factors is human-road-ring in multi-dimensional, with a coupling value of 0.891, in which the driver's bad driving behavior, the sharp bend of the road and the long downhill, and the rain, fog, and ice and snow days of the environment are easy to be coupled with other factors more than 70%, which constitutes a strong coupling relationship and the probability of traffic accidents is large.

Research on knowledge management in coal mine construction safety field based on knowledge graph

XU Na, LIANG Yanxiang, WANG Liang, ZHAO Lili, ZHOU Xueqing, ZHANG Bo

2024, 34(5):  28-35.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0835

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In order to solve the knowledge redundancy caused by data accumulation during coal mine construction, some researches were conducted about domain knowledge management based on KG in this paper. The systematic analysis of the field of standard specification text was conducted using the safety management system structure and security risk management. 12 types of entities and 10 types of relations in the field of coal mine construction safety management were defined, and the knowledge structure model was also improved. 43 standard specifications were selected as data sources for text entity and relationship recognition by rules, dictionaries and deep learning methods. For different entity types, the framework of domain knowledge integrated approaches was proposed, and two models of bidirectional long-short-term memory(BiLSTM) and conditional random field(CRF) and bidirectional encoder representations from transformers(BERT)-BiLSTM-CRF were also compared. The accuracy, recall rate and F₁ value of the BERT-BiLSTM-CRF model are more than 7% higher than that of the BiLSTM-CRF model, which verifies the superiority of the selected model. Through knowledge extraction, knowledge storage and visualization, the entities contained in different types of entities in the field of coal mine construction safety and the relationship between different entities were investigated.

Safety engineering technology

Prediction of pipeline failure probability with multiple failure modes and variable correlation

LI Changjun, ZENG Jianghao, YANG Fan

2024, 34(5):  36-43.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1216

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Aiming at the problem of competing multiple failure modes and dependent variables of corroded pipelines, and low efficiency of predicting the probability of small failures, a time-varying failure probability prediction method for corrosive pipelines based on SS method is proposed. Based on the limit state function of leakage and burst failure, considering the competition between leakage and burst failure, a prediction model for the pipeline competitive failure probability was constructed. In order to solve the above model, the Nataf transformation method was used to describe the correlation between the depth and length of the defects in the simulated samples, and a method to solve the failure probability of corroded pipelines was proposed by considering the competitiveness of failure modes and the correlation of variables. Monte Carlo Simulation (MCS) was used to verify the above method. Finally, the above method was applied to investigate the effect of the weak correlation (correlation coefficient 0-0.3) between defect depth and length on the probability of failure within 15 years of pipeline service. The results show that when the failure probability is greater than 10^-6, the calculation results of this method are basically consistent with those of MCS, and the calculation efficiency is higher than that of MCS, and the minimal probability events with the probability level of 10^-12 can be predicted. Within 15 years of pipeline service, the greater the correlation coefficient of defect variables is, the greater the probability of pipeline burst failure is, and the earlier it reaches the threshold year of burst failure probability. As the correlation coefficient increases, the smaller the probability of leakage failure is, and the later it reaches the threshold year of leakage failure probability. At the later stage of the prediction, the effect of the correlation coefficient increase on the probability of the two kinds of failures is weakened.

Monitoring of settlement in mining industrial square based on optimal PS point acquisition method

YANG Keming, LI Tingting, MA Jun, LI Yaxing, JIANG Kegui, ZHAO Xiangtong

2024, 34(5):  44-51.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1436

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To ensure the safety of the mining ground and underground workers, residents around the industrial square, and the operation of the coal transportation system, real-time monitoring of surface deformation is carried out. An optimized method for acquiring PS points is proposed to enhance the applicability of PS-InSAR technology in settlement monitoring. Firstly, a to total of 26 Sentinel-1A satellite images during the subsidence period of the Industrial Square coal pillar II 513 working face in the Huainan suburban coal mine from October 31, 2020, to August 22, 2022, were selected. The PS-InSAR technology was used to determine the optimal method for selecting PS point targets. Then, based on this method, the ground subsidence rate and cumulative subsidence of the mining damage protection zone during the mining process of the working face were obtained. Finally, the accuracy of PS-InSAR monitoring was verified based on the measured data of ground leveling points, and the dynamic subsidence of the study area's ground and structures was analyzed. The results show that the dual-threshold method of coherence coefficient and amplitude dispersion index is more suitable for subsidence monitoring in the study area. The maximum detectable subsidence rate in the study area is -26.5 mm/year, and the maximum cumulative subsidence value is -53.7 mm. Additionally, geological hazards related to karst collapse were detected in the northwest of the study area. By using leveling data for accuracy verification, the root mean square error (RMSE) is only 3.8mm, and the coefficient of determination reaches 0.91.

Study on erosion characteristics of valve sleeve blowdown valve of shale gas separator

LIU Enbin, LI Xi, KOU Bo, JIANG Jun, LI Dangjian

2024, 34(5):  52-60.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0364

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To solve the problem of severe erosion caused by sand particles passing through separators during shale gas extraction, a well in Changning Shale Gas Field was taken as an example. Based on FLUENT software, numerical simulation was used to simulate the erosion characteristics of sand particles on the drain valve under different speeds, sand content, particle size, shape coefficient and valve opening. The main factors affecting the erosion characteristics of the drain valve were evaluated to clarify the erosion situation of the drain valve. The results indicate that the erosion damage of the valve disc and throttle hole is the main reason for the failure of the sewage valve. As the valve opening decreases, the pressure difference inside the valve increases exponentially, and the flow velocity is the largest at the valve disc and throttle hole. With the decrease of shape coefficient of sand particles, the erosion of the valve is more severe. Based on sensitivity analysis, the degree of influence of various factors on valve erosion characteristics is: ξ_l (Speed)=0.73, ξ_m (Sand particle size)=0.71, ξ_n (Sand content)=0.70 and ξ_q (Shape coefficient)=0.67. Therefore, it is recommended to control the fluid flow rate to within 7 m/s by increasing the internal flow area of the valve, improving the sand removal ability of the desander, and preventing larger sand particles (sand particle size>60 μm) from entering the sewage valve. The sand particle size entering the sewage valve should be controlled within 60 μm, which provides an effective means for the evaluation and optimization of on-site equipment.

Risk ranking of oil and gas pipeline based on improved cloud model-FMEA

WANG Dongying, CHEN Xiaoping, LIU Quan, ZHAO Tianhao, YAN Xu

2024, 34(5):  61-68.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1069

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In order to solve the problems of inaccurate failure priority ranking and excessively subjective risk evaluation in traditional FMEA, a risk evaluation method of oil and gas pipeline failure modes based on a hybrid weights-cloud model was proposed. Firstly, the failure modes and causes of oil and gas pipelines were investigated and analyzed, and the systematic FMEA mode was constructed. Then an expert evaluation opinion processing method was proposed based on the cloud model and the hybrid weight method. The game theory was introduced to reduce the subjectivity and randomness of the evaluation results. Finally, VIKOR was used to rank the risk of each failure mode. The feasibility and accuracy of this method was verified by comparing with the traditional FMEA method. The results show that the method can comprehensively assess the risk factors of pipeline sections, quantify the risk values of different pipeline sections and identify the most important failure modes of the same pipeline section, realizing the effective positioning of pipeline high-risk areas and the ranking of the risk factors of pipeline sections.

Advanced detection response and application of transient electromagnetic field of shallow buried deep coil

WANG Chunyuan, ZHANG Huan, MA Hongliang, LIANG Qinghua

2024, 34(5):  75-81.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1294

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To effectively identify adverse geological conditions such as goaf, karst, and water-conducting fracture zones ahead of the tunnel face and prevent water inflow accidents during tunnel excavation, the application of shallow buried deep coil transient electromagnetic theory in tunnel advanced detection was investigated. A shallow buried deep coil advanced detection model was proposed by COMSOL software to investigate the propagation characteristics and abnormal response features of electromagnetic fields in different directions ahead of the tunnel face. The tunnel project between Jialingjiang Road Station and Xiangjiang Road Station Qingdao Metro Line 13 was used to validate the proposed model's performance in identifying abnormal responses. The results showed that the proposed model can effectively identify low-resistivity anomalies at different positions ahead of the tunnel surface. Moreover, the effect of anomalies in different azimuths on the electric field response was mainly presented in the response intensity. Transient electromagnetic field can effectively distinguish the air zone and rock zone, and the electromagnetic field attenuated faster in the high-resistance surrounding rock near the surface due to the influence of the air zone, resulting in high-resistance anomalies of the practical detection during inversion analysis.

Safety system and management model of subway construction under multi-factor coupling failure mode

FANG Ming, ZHANG Yi, TAN Yue

2024, 34(5):  82-90.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1093

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In order to improve the safety management effect of subway construction and reduce the occurrence of subway collapse accidents, the risk factors of subway construction accidents were analyzed. Firstly, the multi-factor coupling mode of 'human' and 'object' in accident causation were analyzed systematically. On this basis, with the help of accident causation 24Model and GSM, the management model of safety system was constructed. Finally, the multi-factor coupling failure mode of human-object system was applied to 16 existing subway construction collapse accidents. The multi-factor coupling mode and action path of 14 "human" reasons and 6 "object" reasons were given respectively, and their risk levels were calculated. The results show that there are 6 modes and 14 action paths for the multi-factors coupling effect of "human" and "object" in subway construction. The management model is divided into the target layer and the matching layer between the cause of the accident and the safety defense line. The matching layer is constructed from three levels: micro matching, medium matching and macro matching. Based on the established safety system management model of subway construction, the "three defense lines" of subway collapse accident safety construction management were given.

Enhanced permeation effect of fine-grained tailings by ultrasound cavitation

HE Wen, LU Bokai, SHI Wenfang, ZHU Siyu, LIU Jinpeng

2024, 34(5):  91-100.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0014

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The weak permeability of fine-grained tailings can cause the leaching line of the tailings dam to rise and reduce the safety factor of the tailings dam, an ultrasonic cavitation approach was proposed to enhance the permeability of the tailings. Firstly, computational fluid dynamics (CFD) software was used to simulate the cavitation bubble collapse process. Then, the transducer used for the experiments was selected based on the cavitation threshold and the simulated sound pressure, with a frequency range of 20-40 kHz and a power of 60 W. Moreover, the presence of ultrasonic cavitation effects in the tailings samples was confirmed by staining tests. Finally, ultrasound-enhanced permeability tests were performed on tailings samples with different fine particle contents using a self-made variable head permeameter and the selected transducer. A nuclear magnetic resonance instrument was used to determine the pore structure changes before and after penetration enhancement. The results showed that the obtained cavitation bubble radius change curve was consistent well with the Rayleigh-Plesset(R-P) equation fitting curve, proving the validations of the simulations. Low-frequency ultrasound had a better cavitation effect when the bubble diameter was larger than 50 μm, whereas high-frequency ultrasound was more effective when the bubble diameter was less than 25 μm. When the fine particle content was kept constant, the permeability coefficient growth rate of the tailings samples increased as the ultrasound frequency increased. When the ultrasonic frequency was kept constant, the tailings samples' permeability coefficient growth rate with higher fine particles was higher. After the ultrasound treatment, the proportion of 0-10 μm pores in the tailings sample decreased, and the decrease became larger with the increase in frequency. There was no clear trend for the proportion of pores between 10-20 μm, while the proportion between 20-40 μm increased, and the increase became larger with the increase of frequency. The proportion of pores larger than 40 μm increased relatively small. For tailings with different pore proportions, appropriate ultrasound signals of corresponding frequencies can significantly enhance the permeability enhancement effect.

Evolutionary analysis of ship collision risk propagation under a complex network

QIAO Weiliang, DENG Wanyi, MA Xiaoxue, HAN Bing

2024, 34(5):  101-110.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0684

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The event tree analysis(ETA) was applied to the risk propagation process of the risk event chains involved in ship collisions for the purpose of developing directed weighted complex, which was then analyzed according to the topological structure. The traditional K-shell decomposition algorithm was adaptively improved to propose the calculation approach for the absolute criticality of the nodes in the CN. The SIR model was utilized to simulate the risk propagation process within the CN, based on which the dynamic sensitivity of the nodes within CN was analyzed under different cases of infection rates and recovery rates. It is pointed out that approximately 25% of the risk events are found as relatively non-active, and the top 10 critical risk events have no relation with the direct causes of the collision accidents. The sensitivity and criticality of risk events are not consistent at all times, and some risk events would not lead to serious consequences or accidents even though countermeasures are not taken. The existence of direct causes for the collision accidents should be acknowledged for the control and management of risk involved in the ship collisions, and much attention should be paid to the risk propagation process. As a result, differential strategies should be taken during the risk management and control to prevent the ship collisions.

Development on physical model test study on soil nailing supporting slope

CHENG Gang, ZHANG Haoyu, WANG Ye, LI Gangqiang, YOU Qinliang

2024, 34(5):  111-121.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1134

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In order to improve slope stability under the combined action of engineering disturbance and natural factors, and clarify the process and characteristics of slope soil nailing under different loading conditions, the optimal support mode and layout technology suitable for the actual working conditions were selected to ensure the intrinsic safety of the slope structure system. Firstly, the physical model test process and results of soil nailing support under three types of static, vibration, and centrifugal forces were systematically elaborated. Secondly, the characteristics and applicability of typical slope support technologies and new slope support methods were compared as well as analyzed. Finally, through physical model tests under complex environmental effects, the deformation and failure mechanisms of three special slopes, namely submarine slope, typhoon rainstorm slope and high-speed and long-distance landslide were explored. The results show that soil nailing has good applicability in all kinds of slope support, but the reliability and safety factor of slope support under complex and special environments still need to be improved. Therefore, in practice, it is necessary to integrate new materials and processes to conduct research on composite support structures. At the same time, it is necessary to strengthen the selection of similar materials, innovative observation methods, and special environmental simulation research in physical model experiments, aiming to improve the high degree of restoration of monitoring data and achieve the full process safety guarantee of slope systems.

Simulation study on fire spread of different exterior insulation facade structures in high rise buildings

ZHANG Ying, HUANG Guohong, LONG Yujiao

2024, 34(5):  122-128.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1692

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In order to clarify the relationship between the exterior insulation facade structure and fire spread in high-rise buildings, Pyrosim fire simulation software was used to study the impact of different exterior insulation facade structures on fire spread in high-rise buildings. The results show that during the process of fire spread on the exterior facade of high-rise buildings, the insulation systems of different exterior facade structures reduce the air entrainment capacity and heat release rate as the degree of structural space limitation increases. However, their chimney effect is significantly enhanced, and the smoke flow rate is faster, leading to an accelerated vertical fire spread speed. As the thickness of the air layer increases, the temperature and smoke flow rate of the aluminum curtain wall structure insulation system first increase and then show significant fluctuations. The aging of the performance of the external wall insulation system will increase the risk of fire on the exterior facade of high-rise buildings.

Study on smoke transport characteristics of fire inside rail train with multiple lateral openings

PENG Min, PAN Xiangxiao, HE Kun, LI Zhonghui, ZHU Guoqing

2024, 34(5):  129-138.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0758

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In order to study the smoke transport characteristics of rail train with lateral multi-opening and optimize the emergency response strategy for fire rescue, a rail train model was built using PyroSim software based on the engineering entity structure and numerical simulation was conducted. Focusing on the lateral opening as a connecting channel between the inside and outside of the train carriage, the influence of the lateral opening mode on the smoke transport characteristics inside the train was discussed and analyzed. The results show that the lateral opening mode has a significant effect on the smoke transport inside the train, including the smoke spreading speed and the smoke distribution in the stable stage. Compared with the disordered smoke and full coverage in the height direction in the section without opening the lateral opening, the smoke in the section with opening the lateral opening can maintain stable stratification, which is conducive to the safe evacuation and rescue of personnel. The smoke temperature distribution under the train ceiling is more consistent with the double exponential attenuation law, and is affected by the coupling of the opening mode and the fire power. The temperature attenuation rate of the opening section is more significantly affected by the fire power in the asymmetric opening. In addition, although the opening is conducive to the formation of a safe environment inside the train, it is also necessary to consider the impact of the fire smoke spilling into the outer space of the train through the opening to make a comprehensive judgment of emergency response.

Blade defect detection of U-Net network based on attention mechanism

QI Lei, LI Ning, LIANG Wei, WANG Zheng, LIU Ziliang

2024, 34(5):  139-146.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0767

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To solve the issues of wind turbine blades in terms of classification difficulty and blurry segmentation of small defects in surface defect detection, an improved U-Net semantic segmentation network was proposed based on dilated convolution and convolutional attention modules. Based on the encoding-decoding structure of the network model, a transferable VGG16 feature extraction layer was used to replace the encoding part of the U-Net network. Then, a convolutional attention module was added to the skip module between encoding and decoding. The global weight was enhanced by selecting small defect information. Dilated convolution was used in the decoding section to enhance the network's feature extraction ability, and the pre-trained VGG16 model was used to realize transfer learning. The hybrid loss function of Focal and Dice was validated against the models of DeeplabV3+, Pyramid Scene Parsing Network(PSPnet), High-Resolution Network(HRNet), and U-Net. The results showed that the improved U-Net network had higher prediction accuracy in blade defect classification and segmentation tasks, mean intersection over union, mean pixel accuray, and recall values were 83.60%, 92.84%, and 88.50%, respectively. The mean intersection over union simulated by the improved U-Net model was 13.98% and 9.38% higher than that by the DeeplabV3+ and standard U-Net model, respectively. Therefore, the proposed model can improve the sensitivity of blade defect detection, effectively reduce false positives of detection results, and provide guidance to wind turbine blade defect detection.

Mooring maneuver evaluation system based on 3D virtual ships

JIANG Xiaobin, JIN Chunyan, REN Hongxiang, ZHANG Zhiheng

2024, 34(5):  147-154.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0613

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In order to ensure the navigation safety in the process of ship driving and operation and accurately evaluate the practical operation skills of the crew, aiming at the problem of the lack of a complete evaluation index system for the evaluation of ship mooring operation, combining the safety evaluation of mooring operation conducted by the expert evaluation method and fuzzy comprehensive evaluation method, the membership function of each evaluation index was constructed. The analytic hierarchy process(AHP) was used to determine the suggested weight value and the standard value of each evaluation index to ensure the accuracy and reliability of the evaluation results. The three-dimensional virtual ship technology was used to develop a set of mooring maneuvering automatic evaluation systems according to the influence degree of each factor on mooring maneuvering, so as to realize the comprehensive evaluation of the ship's mooring operation. The study shows that the evaluation model has better accuracy, strong systematization, and easy to operate. The results of the system's assessment, when compared with the results of the expert assessment, showed a high degree of consistency, demonstrating the validity and reliability of the model in assessing the mooring skills of crew members.

Firework detection method based on improved YOLO-V5 algorithm

ZHANG Mingzhen, DUAN Jiangzhong, LIANG Zhaowei, GUO Junjie, CHAI Dashan

2024, 34(5):  155-161.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1050

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To reduce the influences of background interference factors in natural environments such as clouds, mist, dust, lights, sunrise, and sunset on the smoke and flame target detection accuracy, a smoke and fire detection algorithm based on an improved YOLO-V5 algorithm was proposed. Smoke, flame target images, and interference image data sets were obtained from the on-site collection and web crawling approaches to solve sample imbalance and improve model generalization ability. A bidirectional feature pyramid network (BiFPN) was used to replace the original feature pyramid network (FPN) + path aggregation network (PAN) structure, and then multi-scale feature fusion on the target was performed to strengthen the model feature fusion ability. At the same time, distance intersection-over-union(DIoU) non-maximum suppression(NMS) is used to replace the original non-maximum suppression (NMS) to speed up the convergence of the detection box loss function and enhance the model reasoning ability. The results showed that the improved algorithm's accuracy, recall rate, mean average precision(mAP) and FPR were 79.2%, 68.6%, 74.2%, and 12.8%, respectively. Compared with the original YOLO-V5 algorithm, the proposed algorithm improved accuracy rate, recall rate, and mAP by 1.9%, 0.9%, and 2.7%, respectively. Furthermore, the FPR was decreased by 3.7%.

Experimental study on ship fire smoke control in large flat-space

LI Sen, WANG Shaopeng, LIN Jin, LU Shouxiang, LI Qian, CHEN Guoqing

2024, 34(5):  162-167.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0252

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To effectively control the smoke spread in large flat-space ships, the oil pool mass loss rate, chamber temperature distribution, thermal insulation efficiency, and smoke control effect were investigated during large-scale fires. The experimental study was performed under three different smoke screen heights (0.35, 0.55, and 0.70 m) and mechanical ventilation conditions in a chamber with dimensions of 30 m×24 m×2.3 m. The results indicated that the increase in smoke screen height caused a decrease in the peak value of the oil pool mass loss. The smoke screen height had a more significant impact on the smoke temperature in the chamber's upper layer than that of the lower layer. The peak temperature above 1.4 m was significantly decreased, whereas no significant change in the peak temperature below 1.4 m was observed. The average ceiling temperature and thermal insulation efficiency decreased with the increase in the smoke screen height. The thermal insulation efficiency increased from 28.2% to 50.8% under the combined smoke control mode, and it increased from 29.4% to 54.7% under the independent smoke control mode.

Cloud model for risk evaluation of coal mine intelligent projects and its application

LI Changming, ZHAO Kaigong, ZHANG Xiaolei, WANG Ruidi, LI Yansu

2024, 34(5):  168-174.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1680

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In order to solve the problems of difficulty in quantifying the indicators and difficulty in taking into account randomness and fuzziness in the evaluation process of the risk of the coal mine intelligentization project, the cloud model theory was adopted to carry out a quantitative and comprehensive evaluation of the system. First of all, based on the coal mine informationization system construction project, a multi-dimensional analysis was carried out to establish a multi-indicator and multi-dimensional evaluation system of the project risk. Then, the combination of hierarchical analysis (AHP) method and criteria importance though intercrieria correlation (CRITIC) method was used to assign weights, determine the weight matrix of the indicators, and the cloud model was used to realize the conversion between the quantitative and qualitative indicators, to complete the evaluation of the risk of the coal mine intelligence project, and to put forward the targeted policy according to the evaluation results. The cloud model was used to realize the quantitative and qualitative conversion of indicators, complete the risk evaluation of the coal mine intelligentization project, and put forward targeted policies based on the evaluation results to minimize the existing risks of the project. Finally, taking a coal mine of National Energy Group as an example, the risk evaluation of the construction and implementation process of coal mine intelligentization project was carried out. The results show that the cloud model can realize the quantitative evaluation of project risks, and the results of risk evaluation coincide with the actual situation on the site; the results of risk evaluation can help to solve the hidden risks on the site and improve the ability of risk control.

Coupling mechanism of air traffic operation safety risk based on N-K-FRAM

LI Yike, ZHANG Honghai, SHI Zongbei, ZHOU Jinlun

2024, 34(5):  175-185.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1552

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In order to explore the coupled evolution mechanism of air traffic operation safety risk, clarify the mechanism of coupling and mutation formation in air traffic operation systems based on a combination of the N-K model and FRAM. Firstly, textual data on unsafe incidents was collected. The risk factors involved were categorized, and their historical frequency of occurrence and the coupling relationship between risk factors were obtained. Secondly, the N-K model was used to solve the coupling degree values between air traffic operational risk factors. Finally, based on the output time and accuracy, the variability of the FRAM functional module was quantitatively evaluated, analyzing the coupling mechanism of air traffic operational safety risks, and safety risk analysis was conducted using regional area navigation(RNAV)approach unsafe events and deviation route unsafe events as examples. The results indicate that the evaluation method based on improved FRAM can quantitatively calculate the variability between functional modules in a reasonable and effective manner, weaken the dependence of traditional analysis methods on subjective consciousness, and make the analysis results more objective and scientific.

Study on inhibition effect of hydrogel on thermal runaway of ternary lithium-ion battery

LIU Chunyuan, ZHANG Guowei, YANG Lin, OUYANG Chenliang, ZHANG Zuorui

2024, 34(5):  186-194.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0104

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In order to quickly and effectively extinguish the lithium-ion battery fire, solve the problems concerned in the fire protection field, such as long fire extinguishing time and high water consumption, and explore the inhibition effect of hydrogel extinguishing agent on the thermal runaway of large capacity lithium-ion batteries. Firstly, the microstructure of hydrogel at high temperatures was analyzed by an environmental scanning electron microscope. Then, by building a lithium battery combustion test platform, the hydrogel fire extinguishing test was carried out. Taking the 135 Ah square aluminium case ternary lithium-ion battery pack for vehicles as the test object, the electric heating method was used to induce its thermal runaway and explore the cooling inhibition effect of hydrogel on lithium batteries. The results show that the pore structure of the hydrogel is destroyed after being heated, which is conducive to its adhesion to the surface of the object and continuous cooling. When using hydrogel for fire extinguishing and cooling, the maximum cooling rate of the battery surface is twice that of water. After the hydrogel is sprayed, the temperature of the lithium battery rises slowly, and the heating rate is only half that of water. Compared with water, the hydrogel can delay the thermal runaway of adjacent batteries for a longer time, which can bring longer safety time for rescue and escape.

Development of causal graph for hazardous chemical accidents

LI Hongru, LUAN Tingting, DENG Mingyue, CHEN Wentao, ZHANG Xue

2024, 34(5):  195-203.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1570

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The causality causal graph of hazardous chemical accidents was developed to improve the safety management level of hazardous chemical enterprises. Firstly, based on the accident investigation report, an entity-relationship joint extraction model was proposed through an improved CasRel technique. Furthermore, the proposed model aimed to improve the extraction accuracy of textual information by incorporating the relationship-aware bidirectional encoder representation method (R-Bert) and Span pointer network. Subsequently, similarity calculation methods were used to generalize the events to enhance the graph's comprehensiveness and accuracy. Then, the refined data was stored in the Neo4j graph database visualizing the associations between events. Finally, the corresponding guestion-answering system was proposed based on the developed causal graph, and then an intelligent question-answering system for the causality of hazardous chemical accidents was proposed. The results indicated that the F₁ value calculated by the improved CasRel model was 90.5%, and the prediction accuracy of the proposed model was 2% higher than that simulated by the original model. The hazardous chemical accidents causal graph and intelligent question-answering system performed well in terms of multiple evaluation indexes, clearly revealing the logical relationship between events. Therefore, the proposed model in this study can meet question-answering needs of hazardous chemical accidents, facilitating the exploration of accident patterns and potential risk factors, and enabling accident trend prediction.

Public safety

A resilience assessment model for multilayer networks of urban interdependent infrastructure

CHEN Changkun, WANG Siqi, SUN Fenglin, YU Rongfu

2024, 34(5):  204-213.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1355

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In order to investigate the influence of interdependent relationships in urban infrastructure systems on urban resilience, a combination of theoretical analysis and Python simulation was used to study the resilience change process of urban interdependent infrastructure systems under perturbation. Firstly, the network of urban interdependent infrastructure was constructed based on the resilience mechanisms and multilayer network theory. Then, the cascading failure process of the urban interdependent infrastructure network after three kinds of external perturbations under the functional linkage was explored, and the resilience assessment model of the urban interdependent infrastructure network was constructed based on the infrastructure function curve method. Finally, a county in the central north of Hunan Province was taken as the research object to conduct an example study. The results show that the clustering coefficient of power nodes in the interdependent infrastructure network is significantly higher than the overall average. The communications network has the strongest resistance and recovery of the 5 types of infrastructure networks and the highest level of resilience. The reliability of the overall interdependent infrastructure network and its sub-networks gradually decreases as the probability of node failure in the network increases, and the number of network layers increases. The network efficiency recovers to a higher level in a shorter time with the betweenness recovery strategy, indicating that it is more appropriate to use the betweenness recovery strategy for this infrastructure network.

Identification of risk factors for through-village highway accidents considering influence of township fairs

JI Xiaofeng, LI Jin, LU Mengyuan, HAN Chunyang, QIN Wenwen

2024, 34(5):  214-222.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1435

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In order to improve traffic safety in the coupling area of the township fair and through-village highway, a secondary road through villages and towns in Yunnan Province was taken as the research object. The core area and the radiation area of the fair were defined according to the affordable travel distance of the township residents and the maximum trading radius of the fair. On this basis, 29 risk factors in 6 dimensions of people, vehicles, roads, environment, management and accident form were selected. The risk factor identification model based on association rules was used to construct the risk factor network of highway accidents through villages and towns. By analyzing the characteristics of network topology, accident risk factors were identified. The results show that the traffic conflict in the core area of the fair is more serious, and the probability of injury accidents is 57.99 %. The core area of the township fair is the primary risk factor for accidents and plays a leading role in the spread of accident risks. The types of direct risk factors for property loss accidents and injury accidents are heterogeneous. Overall, the average clustering coefficient of driver factors is the largest, which makes it easy to produce a chain reaction. In the core area of the fair, the probability of injury accidents increases by 23.71% and 21.07%, respectively, when the driver's meeting vehicles are improper, and the driver does not give way according to the regulations.

Emergency technology and management

Comprehensive evaluation of disaster prevention and mitigation capacity of emergency shelters based on resilience perspective: a case study of Ouhai district in Wenzhou

ZHU Anfeng, FAN Xiufang, DU Wenrui, SUN Wanxin, XU Gang

2024, 34(5):  223-230.  doi:10.16265/j.cnki.issn1003-3033.2024.05.1763

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In order to further improve the basic role of emergency shelters in comprehensive disaster prevention and mitigation, a multi-dimensional evaluation index system for emergency shelters was constructed based on the resilience perspective in five aspects: safety of the place, standardization of management, accessibility to transportation, guarantee of service and reconstruction and recovery. A comprehensive evaluation model was established by combining the Analytic Hierarchy Process(AHP) and Geographic Information System(GIS) spatial analysis. Taking the Ouhai District of Wenzhou City as an example, based on the first comprehensive natural disaster risk survey data and open source data, the disaster prevention and mitigation ability of emergency shelters in the district was comprehensively evaluated, and the scientific and effectiveness of the model was verified. The study shows that the constructed index system and comprehensive evaluation model can be used to analyze and evaluate the disaster prevention and mitigation ability of emergency shelters, the weak indicators of emergency shelters can be found, and the direction of optimization and improvement can be provided for managers. In the case analysis, the low resilience emergency shelters in Ouhai District are mainly concentrated in the western mountainous areas, and the resilience of village-level emergency shelters is relatively low, which is consistent with the actual situation, proving.

Emergency supply chain reliability evaluation based on combined empowerment-bias order set

WANG Dan, GAO Wenwen

2024, 34(5):  231-237.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0700

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In order to coordinate the distribution and use of materials in the emergency supply chain, the reliability evaluation indexes of the emergency supply chain were refined based on literature analysis. The reliability evaluation index system of the emergency supply chain was established, which was composed of three first-level indicators of organizational guarantee reliability, system institutional reliability and operation process reliability and 17 corresponding second-level indicators. AHP, EWM, and trigonometric fuzzy number were used to calculate the index weights, and the partial order relationship containing weight information was introduced into the evaluation, and the combined weighting-partial order set model was constructed to evaluate the reliability of the emergency supply chain. The reliability level of the emergency supply chain in five county-level cities of city C was evaluated and analyzed by using the model. The results show that the reliability of the emergency supply chain in the five county-level cities can be divided into four categories, among which the reliability level of region 03 is high, the reliability level of region 04 and 02 is relatively high, the reliability level of region 05 is medium, and the reliability level of region 01 is low. Through comparative analysis, the strengths and weaknesses of each region, and the areas needing improvement are obtained. This evaluation model can effectively evaluate the reliability level of the emergency supply chain.

Emergency ship maneuvering method for crossing encounter situation under immediate danger threat

WU Jianjun, CHEN Yan, ZHU Qinghua, HU Shenping

2024, 34(5):  238-246.  doi:10.16265/j.cnki.issn1003-3033.2024.05.0910

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To prevent collision accidents caused by ships failing to take timely and effective avoidance actions due to unclear situation awareness, an emergency ship maneuvering method aimed at addressing urgent dangerous threats was proposed. Based on the data from collision accident investigation reports, the ship encounter process was reconstructed. Considering the uncertainty and randomness of the ship collision risk, a bell-shaped grey cloud model was developed to obtain PCR in real-time and reveal its temporal evolution characteristics. The Kriging spatial interpolation algorithm was used to obtain the perception and graph representation of PCR between two ships. Furthermore, an avoidance decision-making assessment index was proposed to provide emergency maneuvering methods for steering collision avoidance. The validations of the collision accident in the crossing situation indicated that steering avoidance could effectively avoid a close-quarters situation if the give-way ship had taken action by the rudder in a crossing situation and turned starboard by 112.5° before the time of closest point of approach (TCPA) was 10 min. Furthermore, if the give-way ship did not take any action, the stand-on ship should turn to starboard by 45° before the TCPA was 4 min to effectively avoid immediate danger. This study proposes a fine-grained accident data-driven emergency ship-handling method that can be implemented in conjunction with traditional radar mapping and nautical experience ship-handling methods.