China Safety Science Journal

Research on employees' unsafe behavior in China from 1949 to 2018: development stage, research hotspot and trend analysis

LIU Lin, MEI Qiang, CHANG Zhipeng

2021, 31(3): 1-12. doi:10.16265/j.cnki.issn1003-3033.2021.03.001

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In order to review and summarize research progress on unsafe behavior in past 70 years, and to promote theoretical research on safe behavior management, a total of 564 journal articles from 1949 to 2018 were analyzed by using bibliometrics and CiteSpace mapping knowledge analysis tools. Growth law of unsafe behavior research was explored, co-occurrence knowledge mapping of authors and research institutions was drawn and influential authors, institutions and their cooperative characteristics were identified. The results show that unsafe behavior research goes through three stages in China, i.e., initial infancy stage (1949-2003), growth I stage (2004-2013) and growth II stage (2014 to date), and different hotspots have emerged in these stages. Future studies should be more focused on shortcomings of previous research as well as new development trend.

Prediction method of actual operating landing distance based on similarity theory

SUN Ruishan, CHEN Xiong ,LI Chongfeng

2021, 31(3): 13-18. doi:10.16265/j.cnki.issn1003-3033.2021.03.002

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In order to prevent plane from overshooting runway on landing, a method was proposed to predict flights' actual operating landing distance based on similarity theory. Firstly, combined dimensional analysis with main factors that affect actual landing distance of aircraft, dimensionless equation that characterize operating landing distance was obtained. Then, digital flight data was used to further establish equation that predict flights' actual operating landing distance under different touchdown pitch angles. Finally, prediction values of equation were compared with actual operating landing distance of aircrafts. The results show that this method is able to predict flights' actual operating landing distance and deviation between predicted value and practical value is minimum under condition of small touchdown pitch angle. The maximum absolute error is less than 50 meters, and the maximum relative error is about 3%.

DOA method of gas leakage source based on WOA

LI Peng, CHANG Sijie

2021, 31(3): 19-27. doi:10.16265/j.cnki.issn1003-3033.2021.03.003

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In order to reduce real-time estimation error of gas leakage position in pressure vessel, thereby accurately monitoring its working conditions and preventing accidents, firstly, a leakage source estimation method based on WOA was proposed from perspective of acoustic monitoring, and DOA was used to predict leakage location direction to obtain angle coordinates of leak source. Then, WOA adaptive selection method was introduced to decompose characteristic value of DOA, and the most accurate leak location was acquired through multiple iteration. Finally, with pressure vessel in a chemical plant as an example, estimation results of leakage source based on WOA were compared. The results show that this method can precisely define location of leakage in pressure vessel, and it is found to have better robustness and anti-noise performance than traditional DOA and DOA methods based on other bionic intelligent algorithms according to performance simulation curves. Moreover, it has a positioning accuracy rate as high as of 95%, ans can save time consumption by 92.2%, thus enhancing real-time nature of engineering applications.

Prediction of failure pressure of corrosion pipelines based on RS-PSO-ELM

LUO Zhengshan, TIAN Peiqi

2021, 31(3): 28-34. doi:10.16265/j.cnki.issn1003-3033.2021.03.004

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In order to improve prediction accuracy of corrosion pipelines' failure pressure and simplify its calculation process, a prediction model based on RS, PSO and ELM was proposed. Key factors that affected failure pressure were extracted in a way of attribute reduction, PSO was selected to optimize input weight and hidden layer deviation of ELM, and normalized core index data were computed in calculation. The results show that prediction of the model is basically consistent with actual values, its mean square error (MSE) is reduced to 0.255 compared with single ELM model, and absolute mean error is reduced to 0.32 compared with other assessment models of failure pressure.

Study on comparison of leak frequency sources in chemical plants

HUA Junjie, SHEN Mandui, SONG Xiansheng

2021, 31(3): 35-40. doi:10.16265/j.cnki.issn1003-3033.2021.03.005

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In order to reduce influence of leakage frequency on uncertainty of quantitative risk analysis results of chemical plant, leakage frequency data sources published by China, UK health and safety authority, norske veritas and International Association of Oil and Gas Producers (IOGP) were compared and analyzed from aspects of covering equipment and facility types, benchmark leakage frequency and frequency calculation model. Taking two leakage units of a chemical plant as an example, leakage frequency calculation results and quantitative risk analysis results of two data sources, national standard for Determining External Safety Protection Distance of Hazardous Chemical Production Plant and Storage Facility and IOGP were compared. The results show that leakage frequency published by IOGP belongs to open data sources published by international authoritative institutions, and has a leading advantage in data sources, equipment and facility types, computing models and reliability of results. IOGP leakage frequency data source can be used as a priority for chemical plant leakage frequency correction and quantitative risk analysis.

Study on synergistic suppression of methane explosion by porous mineral materials-ammonium polyphosphate composite powder

YUAN Bihe, TAO Hongji, SUN Yaru, WANG Liancong, CHEN Xianfeng, TAN Hai

2021, 31(3): 41-46. doi:10.16265/j.cnki.issn1003-3033.2021.03.006

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In order to ascertain explosion suppression efficiency of a novel porous mineral material (Trade name: MTS)-APP powder inhibitor, a 20 L spherical explosion experimental apparatus was employed to study suppression effects of MTS, APP and their mixtures with different component proportions and added concentrations on methane-air explosion. Their pyrolysis behavior were evaluated by using a thermal analyzer. The results show that the synergistic inhibition effect of composite powder on methane explosion is most obvious when the addition of powder is 0.100 g/L and the ratio of porous mineral to APP is 1∶3 with the weakening of each explosion parameter. Synergistic explosion suppression mechanism of MTS-APP powder consists of physical and chemical inhibition performances. The porous structure endows MTS with labyrinth effect, which enhances free radicals trapping ability. The successive endothermic decomposition reactions of MTS and APP can persistently absorb heat. Moreover, the decomposition products have the effects of dilution, cooling and isolation, and can consume the free radicals in the combustion reaction.

Multi-dimensional control model of interval AIS data-driven berthing process

QIN Tingrong, LI Dongyang, LI Penghao, MA Guoliang, CHEN Weijiong

2021, 31(3): 47-53. doi:10.16265/j.cnki.issn1003-3033.2021.03.007

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In order to improve berthing safety and docking intelligent berthing, attitude control in the process of ship docking was realized, through using some optimization strategies such as Chebyshev fitting method, 95% confidence interval method, least 2 method,two times fitting of above combination method and so on. Berthing control parameters, such as speed, heading, heading and ship position were fitted in the data of interval vessel AIS. A multi-dimensional attitude control model driven by interval AIS data was constructed, and reliability of model was tested by AIS data of a certain wheel berthing in Longtan Port, Nanjing for one year. The results show that model fitting method is superior to existing fitting method, and output results are in line with relevant rules, and proposed model meets requirements of ship attitude safety control during docking process.

Experimental study on effect of spherical obstacle on gas deflagration flame

WANG Lei

2021, 31(3): 54-59. doi:10.16265/j.cnki.issn1003-3033.2021.03.008

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In order to further develop explosion-proof technology and equipment for underground gas explosion accidents in coal mines, gas deflagration propagation experiment was carried out when there were no obstacles and when there were spherical obstacles by using a square pipe with a cross section of 0.2 m×0.2 m, schlieren device and high-speed camera. Study shows that when there are no obstacles, structure and propagation speed of deflagration flame in a sealed pipeline are greatly affected by reflected pressure wave. Mutual game between turbulent flame, chemical reaction ability, and reflected pressure wave is main reason for change of flame propagation speed. When a spherical obstacle exists, flame is disturbed and stretched into a front, a center and a tail, and front is the fastest, tail is the slowest. Flame front has an overall acceleration trend from passing obstacle. Compared with obstacle, time to pass observation period is significantly shorter.

Improved catastrophe progression method for evaluating supporting effect of bolts in mining roadway

LI Jing, HU Bin, LIU Yanzhang, CUI A'neng

2021, 31(3): 60-65. doi:10.16265/j.cnki.issn1003-3033.2021.03.009

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In order to determine comprehensively bolt support effect of mining roadway under influence of various factors,an improved catastrophe progression method was proposed to evaluate supporting effect of bolts in mining roadway. Firstly, based on multi-layer decomposition of factors affecting roadway bolt support effect, index importance ranking problem in catastrophe progression method was improved by dispersion maximization method. Then, evaluation model of bolt support effect based on improved mutation progression method was constructed, and evaluation series of roadway bolt support effect was calculated. Finally, feasibility and reliability of model were confirmed by evaluating effect of roadway bolt support on 20 samples and verifying by numerical simulation. The results show that improved catastrophe progression method considers relative importance of each index. Evaluation results are accurate, which provides a new method for evaluation of bolt support effect.

Research on crack propagation of pipeline inner surface defect under external force

ZHU Haohao, GUO Hailin, ZHUMAKELDI A

2021, 31(3): 66-72. doi:10.16265/j.cnki.issn1003-3033.2021.03.010

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In order to improve accuracy of pipeline safety risk assessment, taking pipeline with internal surface defects as research object, influence of different size defects on crack initiation law was analyzed by using ABAQUS software linear elastic and elastic-plastic,3-point bending model of pipeline and full-scale static load physical test were established by using extended finite element method, and nonlinear fitting of crack growth size was used to study crack propagation at the inner surface defects. The results show that crack initiation is very easy at the center of inner surface defect.As the size of the defect increases, the external force required for crack initiation changes greatly when the relative length of the defect is 0.08 and the relative depth is 0.4,and influence of defect depth on crack initiation is greater. Comparison between numerical simulation and full-scale physical test shows that crack size rapidly expands under displacement load of less than 70 mm or external force of 147.25 kN, and then nonlinear fitting of crack size can obtain more accurate prediction results of crack growth size.

Dynamic risk analysis of gasifier overtemperature scenario based on DBT-DBN

GAO Han, DUO Yili, SUN Tie, WANG Zhirong, GUO Pinkun

2021, 31(3): 73-81. doi:10.16265/j.cnki.issn1003-3033.2021.03.011

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In order to strengthen safety risk management of gasifier in coal gasification units, a dynamic risk analysis approach based on DBT and DBN was applied to construct an analysis model of gasifiers' overtemperature risks. Firstly, DBT model was established by analyzing sequential dependency of failure events, and their probability was determined considering fuzzy evaluation. Then, DBT model was mapped into DBN, linguistic variables were converted into prior probabilities, and risk factors were obtained through bidirectional reasoning. Finally, dynamic risk trend of gasifier overtemperature and consequences was predicted, and critical factors were identified by diagnosis reasoning. The results show that probability of gasifier overtemperature is about 64.4% after one year with maintenance factor taken into consideration. Among all key factors, operation error in production cycle has a greater impact, and equipment faults mainly occur in coal grinding and pulping section.

Development of monitoring device for physiological condition of workers in confined space

XU Yifei, JIN Longzhe, WEI Yixuan, YU Lu

2021, 31(3): 82-89. doi:10.16265/j.cnki.issn1003-3033.2021.03.012

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In order to monitor abnormal physiological conditions of workers in confined space so as to ensure operation safety and their lives and health, the best signal acquisition position was obtained based on analysis on signal quality of 6 measurement positions at wrist. Then, considering accident causes, physiological parameters such as heart rate, pulse period, and amplitude were extracted from PPG signal as evaluation indicators, and a wrist pulsation physiological information monitoring device for people with special operations in limited space was developed. Afterwards, system stability was tested. The results show that inner center of wrist is the best signal collection position, and the device operates stably in confined space motion state, which can realize real-time non-invasive monitoring and early warning of workers' physiological state.

Experimental study on mechanical properties of coal under different gas pressure

ZANG Zesheng, LI Zhonghui, NIU Yue, LIU Shuaijie, SONG Jingjing, ZHANG Quancong

2021, 31(3): 90-95. doi:10.16265/j.cnki.issn1003-3033.2021.03.013

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In order to study influence of gas on mechanical properties of coal, a uniaxial compression test of coal under different gas pressure was designed. Change trend of coal samples' mechanical parameters and deformation characteristics along with gas pressure was studied to explore influence mechanism of gas on their mechanical properties, their parameters under uniaxial compression were obtained, and failure mode was recorded. The results show that with increase of gas pressure, compaction stage of stress-strain curve increases while elastic stage decreases, and the curve decreases slowly after instability failure. Meanwhile, compressive strength and elastic modulus decrease monotonously while peak strain increases monotonously. Cracks of coals with no gas produced under load are relatively simple, but gas-containing coal samples, after being damaged under load, see obvious main cracks and multi-directional bifurcation cracks as well as partial coal body shedding.

Prediction model of rockburst grade based on PCA-neural network

ZHANG Kai, ZHANG Ke, LI Kun

2021, 31(3): 96-104. doi:10.16265/j.cnki.issn1003-3033.2021.03.014

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In order to predict rockburst disaster accurately and reliably, RBFNN, PNN and GRNN prediction models based on PCA were established. Six frequently-used parameters were chosen to constitute prediction indicator system, PCA was used to eliminate correlation of indicators and reduce their dimensionality. Then, three linearly independent pivot elements were obtained, namely three comprehensive indicators Y₁, Y₂ and Y₃, which constituted input vectors of RBFNN, PNN and GRNN neural networks. The results show that predictions of three PCA neural network models are better than original RBFNN, PNN and GRNN models as they not only improve accuracy, but also shorten operation time. Moreover, according to comparison from three aspects of local accuracy, overall accuracy and operation time, these three models ranks as PCA-GRNN > PCA-PNN > PCA-RBFNN > PNN > GRNN > RBFNN from strong to weak based on their accuracy ability.

Study on critical velocity of lateral point smoke extraction tunnel fire

JIANG Xuepeng, CHEN Xin'ge, GUO Kun

2021, 31(3): 105-111. doi:10.16265/j.cnki.issn1003-3033.2021.03.015

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In order to obtain dimensionless formula to calculate critical velocity of tunnel fire in lateral point smoke extraction pattern, dimensional analysis was made on relevant influencing factors of critical velocity according to π theorem and similarity theory, and a dimensionless functional relation of three influencing factors were derived. Then, numerical simulation was conducted to define quantitative relationship between critical velocity and fire heat release rate, smoke exhaust volume and distance between smoke vent and fire source. The results show that when distance between dimensionless smoke vent and fire source is less than 2.22, critical velocity increases along with increase of distance by 1/25 power, but decreases along with increase of smoke exhaust by -3/50 power. However, when it is greater than 2.22, critical velocity no longer changes with either distance or smoke exhaust. Meanwhile, with increase in heat release rate, it always rises by 1/3 power.

Traffic flow simulation of urban three-lane road considering influence of accident vehicle

JI Hao, WANG Yongdong, LI Pei, SU Bing

2021, 31(3): 112-120. doi:10.16265/j.cnki.issn1003-3033.2021.03.016

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In order to explore impact mechanism of accident vehicles on urban three-lane road traffic, firstly, characteristics of traffic flow on such roads were analyzed considering influence of accident vehicles. Then, a traffic flow model of cellular automaton was established which featured left lane priority and active and passive behavior of risky lane changing. Finally, traffic flow evolution along with change of accident durationt_dwas studied when accident vehicle was located on lane M and R respectively. The results show that accident vehicle would cause traffic bottleneck with space-time characteristics of vehicles gathering upstream and sparse vehicles downstream, thus inducing traffic congestion. It has less impact on three-lane traffic than on two-lane traffic, and the same when it is on lane M than on lane R, but the difference of its impact decreases along with increase of p_e.

Simulation analysis of window fire spread in super high-rise building at different temperatures

WANG Yu, XING Jia, ZHOU Yingtong

2021, 31(3): 121-127. doi:10.16265/j.cnki.issn1003-3033.2021.03.017

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In order to study influence of different temperature conditions on flame fusion height of window plume of concave super high-rise building, fire model of concave super high-rise building under different temperature conditions were numerically simulated by PyroSim software, and temperature distribution isotherm and temperature curve of longitudinal continuous multiple windows were analyzed. The results show that flame height increases by 4.5-5.9 m when dangerous temperature reaches 540 ℃ at 3 windows compared with 2 windows in longitudinal continuous window.When dangerous temperature reached 350 ℃, flame height increased by 11.0-13.3 m. Flame height increases by 3.0-3.4 m when longitudinal continuous 4 window compared with 3 window combustion at dangerous temperature of 540 ℃. When dangerous temperature is 350 ℃, flame height rises by 7.8-9.5 m. For concave super high-rise building, the greater the temperature difference between indoor and outdoor, the higher the flame fusion height. Begin from longitudinal continuous 3 windows, growth trend of flame fusion height decreases.

Study on navigation safety under influence of riverbed evolution in bridge area

KONG Xianwei, ZHANG Qinghe, YANG Zongmo, QI Chunfeng, CHEN Shu, ZHANG Hu

2021, 31(3): 128-134. doi:10.16265/j.cnki.issn1003-3033.2021.03.018

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In order to scientifically design bridge span scheme for changeable riverbed, case analysis and historical analysis methods were employed to study the problem of Jingzhou Yangtze river bridge area where navigation safety was impacted by riverbed evolution. It was pointed out that the most significant risk for bridges in changeable riverbeds was that channel displacement caused by riverbed evolution made ship navigation move from navigable bridge opening to non-navigable one, and it was suggested that navigable bridge opening should cover thalweg and swing range of deep channel which may form new navigation channel. Then, riverbed evolution mechanism of Libu bridge area which was planned to be built was studied according to proposed principles, swing range of 3.5 m deep channel and thalweg under the lowest navigable stage was chosen for bridge span layout. Finally, 1 120 m scheme was confirmed to be able to guarantee navigation safety of Libu Yangtze river bridge under influence of riverbed.

Simulation analysis of passenger restraint system in coach frontal collision

SI Junde, LI Jianping, ZHANG Boqiang, SUN Mingying

2021, 31(3): 135-141. doi:10.16265/j.cnki.issn1003-3033.2021.03.019

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In order to study impacts of restraint system on occupant injury in a frontal collision of a coach, a simulation model of frontal crash was built by using LS_DYAN, and a crash experiment was performed at 50 km/h with 100% of coach front striking a rigid barrier. Then, the simulation model was validated against crash-test in terms of vehicle deformation, acceleration, and occupant injury. Finally, based on verified model, comprehensive analysis and evaluation were carried out on occupant motion response and injury for conditions, including different seat pitch, carriage position, and seat belt type. The results show that overall trend of acceleration time-history at different positions is similar, but specific peak and its timing are different. Increasing seat pitch and active pretension seatbelt can effectively reduce value of head injury while raise that of neck injury. Chest injury value and femur force of passengers are not greatly affected by active pretension seatbelt, seat pitch, and carriage position.

Model construction and analysis of fire stress response process of subway passengers

LIN Xiaofei, LIN Biyi, SONG Shouxin, YU Xiao, SHEN Fan

2021, 31(3): 142-147. doi:10.16265/j.cnki.issn1003-3033.2021.03.020

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In order to improve coping abilities of subway passengers against fire, a theoretical model of fire stress process was constructed based on the stress response model. Then, 357 valid questionnaires were collected, factor analysis and SEM were used to explore six variables of individual characteristics, specific situations, cognitive evaluation, social support, coping styles and coping outcomes as well as interaction between them. The results show that individual characteristics can positively regulate results of psychological response, while specific situation variables can reversely regulate them. Cognitive evaluation has a significant positive mediating effect on them, while coping style and social support have no significant ones. Specific situation can have a significant positive impact on coping style, cognitive evaluation and social support.

Urban fire risk assessment and planning response based on multi-source data

WANG Ai, ZHANG Qiang, LU Lin, YU Haoran, HUANG Chaowei

2021, 31(3): 148-155. doi:10.16265/j.cnki.issn1003-3033.2021.03.021

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In order to analyze spatial pattern characteristics of city fire risks, a scientific fire prevention and control system was proposed and Hefei was selected as case study. Based on POI data, NPP/VIIRS light data,fire station data, road information and other multi-sourced data. SAVEE model and iterative method were used to assess risk of urban fire.Location-allocation(L-A)model was introduced to evaluate current city fire stations and layout of fire stations was optimized from different target situations.The study shows that high risk areas of fire are mainly concentrated in the built-up areas within the second ring road of Hefei city, especially old urban area, west railway station area, administrative area, science city and new center in the east. Existing 48 fire stations have a good coverage rate of POI in study area, with a coverage rate of 86.76%, while coverage rate of NPP/VIIRS is only 55.94%. Coverage rate is still insufficient in the northeast, northwest and south parts of Hefei. Based on the maximized coverage model, 44 new fire stations are planned to significantly increase coverage of response time of 5 min, which can further consolidate urban fire safety.

Study on natural smoke extraction model in semi-underground tram station fire

REN Fei, SHI Congling, LI Jian, CHE Honglei, XU Xuan

2021, 31(3): 156-161. doi:10.16265/j.cnki.issn1003-3033.2021.03.022

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In order to verify smoke exhaust effect of natural smoke exhaust mode in semi-underground tram station fire, taking a typical tram station in a city as research object, a full scale model was established by numerical simulation method for calculation, evolution characteristics of temperature distribution in station space, velocity of smoke exhaust outlet and escalator exit in semi-underground tram station under train fire were studied,airflow field, smoke movement process and control effect of natural smoke exhaust mode in semi-underground station fire were analyzed. The results show that for semi-underground tram station, natural smoke exhaust mode can prevent smoke from falling to dangerous height within specified time (6 min),which can be used in the design of same tram station,under natural smoke exhaust mode, air distribution is mainly controlled by thermal buoyancy of fire smoke, which can not maintain stable air distribution and make-up air flow rate at the escalator entrance, which has certain limitations.

Road factor analysis of taxi speeding behavior considering spatial effect

ZHOU Yue, FU Chuanyun, JIANG Xinguo, MAO Chengyuan, LIU Haiyue

2021, 31(3): 162-170. doi:10.16265/j.cnki.issn1003-3033.2021.03.023

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In order to prevent taxi speeding by utilizing road characteristics, GPS trajectory data of taxis in Chengdu city area were gathered to identify their speeding behavior, and road characteristics were extracted as well. Then, with speeding frequency and average speeding severity of each road as speeding characteristics, global Moran's I and four kinds of spatial regression models were adopted to analyze spatial autocorrelation of speeding characteristics and road factors and to explore significant influencing factors of the former. The results reveal that obvious spatial autocorrelation exists between taxi speeding and road characteristics. Spatial Autocorrelation Model (SAC) and Spatial Durbin Model (SDM) are the best for fitting of speeding frequency and average speeding severity estimation, respectively. Number of connected road, access number and lane number evidently increase taxi speeding frequency while road length and lane number significantly increase average speeding severity. Whereas, work zone and one-way roads are unrelated with speeding characteristics.

Time-series risk assessment model for disaster evolution network

ZHAO Dongyue, CHEN Changkun, YI Liang

2021, 31(3): 171-177. doi:10.16265/j.cnki.issn1003-3033.2021.03.024

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In order to explore time-varying characteristics of risk during disaster evolution and feasibility of time-series risk assessment, such an assessment model for disaster evolution network was firstly constructed by adopting disaster evolution theory and methods. The model was mainly composed of four sub-models, including disaster loss degree, disaster occurrence probability, disaster direct risk and comprehensive risk based on factors like chain effects of disaster, time-varying consequences and government intervention. Then, the model's feasibility was verified through numerical examples. Finally, its superiority was analyzed. The results show that the constructed model could not only evaluate direct and comprehensive risk for disaster evolution network and obtain their dynamic change trend, but also analyze high-risk occurrence time and duration of key nodes in the network.

Evaluation and analysis on influence of industrial noise on brain cognition based on EEG power spectrum

QI Zuoqiu, WANG Hong, ZHAO Xiaobing, WANG Qiaoxiu

2021, 31(3): 178-183. doi:10.16265/j.cnki.issn1003-3033.2021.03.025

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In order to clarify negative impact of industrial noise on brain cognition, noise of ball mills in a thermal power plant was collected, and 32-channel EEG signals of 10 college students under steady-state industrial noise (90 dB(A)) and quiet state were recorded. Then, Fourier transform Welch method was used to analyze data in frequency domain, and power spectrum of δ band, θ band, α₁ band, α₂ band and β band was extracted for statistical analysis. The results show that power spectrum is significantly increased in δ and θ frequency bands in noisy environment than silent one. And in frequency band α₁, its value in noise state is higher than silent state, but the opposite in band α₂. Stimuli of productive noise can cause subjects to distract, and its impact on cognition can be evaluated by power spectrum value or ratio parameter in each band.

An EEG study on semantic cognition and emotional evaluation for traffic signs

LU Guoying, ZHANG Ting

2021, 31(3): 184-190. doi:10.16265/j.cnki.issn1003-3033.2021.03.026

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In order to make drivers understand traffic signs more correctly and quickly, avoiding improper driving behavior, and improving driving safety, semantic cognition and emotional evaluation for traffic signs was investigated. Objective evaluation indicators of semantic congruence and emotional arousal of traffic signs using ERPs measurement combined with EEG time-frequency(TF)analysis was explored and a S1-S2 paradigm was adopted. The result shows that a larger N400 and θ activity in the same time window were elicited by semantically incongruent traffic sign and word pairs, which indicated semantic distance between traffic signs and words. A larger late positive potential (LPP) was induced by semantically congruent traffic sign-word pairs. It implied emotional arousal of participants. N400, θ wave and LPP can be used to determine semantic distance and emotional arousal in traffic signs. The results of ERPs combined with EEG TF analysis can provide a neuroscientific interpretation of behavioral data and it can be employed to measure traffic sign comprehension.

Research on muscle fatigue and accident prevention in coal miners

WANG Yue, ZHANG Lin

2021, 31(3): 191-196. doi:10.16265/j.cnki.issn1003-3033.2021.03.027

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In order to solve problem of miners' work intensity and difficulty, it was easy to cause physical fatigue and lead to unsafe behavior. Firstly, questionnaire of muscle fatigue was issued to miners to understand actual working state of miners. Secondly, surface EMG test was used to simulate working environment and work content of miners, and degree and change characteristics of muscle fatigue were detected. Finally, combined with experimental results and working status of miners, prevention and control measures of muscle fatigue accidents were put forward. The results show that proportion of muscle fatigue in the neck, shoulder, back, elbow, waist and other parts of miners is high. It is suggested that miners should take a rest before fatigue instability period to avoid or delay fatigue, reduce unsafe behaviors and reduce rate of human accidents. Prevention and control measures of muscle fatigue accidents of miners can be carried out from aspects of working time early warning, working environment early warning, psychological stress warning, comprehensive early warning files and mechanical amenity design.

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