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A fire Escape Simulation System Based on the Dijkstra Algorithm

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Computer Systems Science & Engineering 2021年第12期39卷 365-372页

作者： Haolong Yang Chunqiang Hu Guwei Li Jingchun Fan ChongQing University ChongQing400000China Zhejiang Dongfang Polytechnic WenZhou325000China Compugen Ltd TorontoM2J 4A6Canada

Despite the support of all kinds of fire prevention measures and high-tech fire prevention equipment,fires still occur frequently because of both anthro-pogenic factors and natural disasters.This issue has drawn the attention of schools,all levels of government,and other organizations.Many types of organi-zations carry out fire drills throughout the year.Because this kind of drill cannot anticipate the specific circumstances of each fire,which are generally far more complicated than drills,most people cannot correctly choose the optimal escape route from real fires.Thus,a fire-scene virtual simulation system based on the Dijkstra algorithm is here proposed to address such problems as casualties caused by frequent fires and the inability of most people to correctly choose a fire escape route.This virtual fire escape simulation system uses Maya to carry out 3D recon-struction of the fire scene,the Unity engine to conduct interactive function design,and the Dijkstra algorithm to calculate the best escape route.The results of the example indicate that the simulation system solves the problems of the traditional simulation system,such as stiffness,lack of intelligence,and poor simulation.

关键词： Dijkstra algorithm virtual fire escape simulation system fire

The forecast of fire impact on Pinus sylvestris renewal in southwestern Siberia

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Journal of Forestry Research 2021年第5期32卷 1911-1919页

作者： Stanislav NSannikov Nelly SSannikova Irina VPetrova Olga E.Cherepanova Botanical Garden of the Ural Branch of Russian Academy of Science 202a8 Marta St.Yekaterinburg 620144Russia

Simulation of fire impact on forest floor renewal in pine forests was based on predictions for 2100 by the Canadian Climate Centre for increase in temperatures of by4.5℃and total precipitation by 14%in the West Siberian pre-forest-steppes and empirical regression relationships between them and the degree of burnt forest floor,as well as amount of Pinus sylvestris L.regeneration.It was predicted that by 2100,pine regeneration on fire prone sites under the canopy of the dominant forest type will increase by 29-54%compared to the 1980 s but on adjacent open sites,regeneration will decrease twice as much.This means that the regeneration potential and pine population stability in pre-forest-steppes will become as poor as it is today.

关键词： fire Forecast Stability Population Mathematical model Seeds Imitation model Undergrowth

Development of a model to generate a risk map in a building fire

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Science China(Technological Sciences) 2010年第10期53卷 2739-2747页

作者： CHU YanYan, ZHANG Hui, SHEN ShiFei, YANG Rui & QIAO LiFeng Center for Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China Center for Public Safety Research Department of Engineering Physics Tsinghua University Beijing China

fire simulations and sensors are widely used in building fires,various data such as temperature,CO and CO2 concentration,visibility can be obtained by sensors and sensor-based simulation. It is important to generate a risk map based on such data so that we can use it to estimate safety of the building. In this paper,we propose a method to generate a dynamical,integrated risk map using sensor readings in a building fire. Such risk evaluation model is developed using similarity comparison between the space state and dangerous state by a likelihood distance calculating and data grouping from a two-step cluster method. The risk evaluation model considers the integrated influence on the occupants in the zone from high temperature,lack of oxygen,toxic and harmful gases and shows the relative fire risk map at certain time. Based on the simulation study,it is proved that multi-factor fire risk analysis would be more objective and accurate than single factor and two-factor risk analysis and the fire risk evaluation model can generate a risk map and provide the classification information and the whole building risk statistic results to support evacuation command and control.

关键词： building fire risk map cluster analysis fire simulation

Trajectory from beech and oak forests to eastern broadleaf forests in Indiana, USA

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Ecological Processes 2019年第1期8卷 21-28页

作者： Brice B.Hanberry USDA Forest Service Rocky Mountain Research StationRapid CitySD 57702USA

Background:Historical forests(circa 1799 to 1846)of Indiana were predominantly composed of American beech(25%of all trees)and upland oaks(27%of all trees).I compared historical forest composition,using studies of smaller areas to approximate composition for uncommon species or genera(<4.5%of all trees)and forest types,to current forest composition and forest types in Indiana.I also compiled published historical density estimates from small studies and estimated current density for the state.Results:Current forests are diverse with an even composition of many eastern broadleaf species.In addition to upland oaks,which decreased to 13%of all trees,only sugar maple currently comprises greater than 10%of all trees.Other increasing species were yellow-poplar,red maple,black cherry,and eastern redcedar.Eastern redcedar increased from no presence to one of the most abundant ten species(≥3.5%of composition),similarly to the pine genus,becoming more common currently than American beech.Beech or oak or beech-oak forest types(≥24%of all trees)became eastern broadleaf forests,with no dominant species,and black cherry,red maple,and eastern redcedar forest types now occurred.Estimates of historical oak or beech forests ranged from 28 trees per hectare to 175 trees per hectare,which probably represent savannas and woodlands.Current mean density of Indiana forests is 385 trees per hectare,ranging from 180 trees per hectare to 450 trees per hectare.These forests likely contain dense layers of woody vegetation,filling the midstory and replacing herbaceous vegetation in the ground layer.Conclusion:Historically dominant beech and oak forests in the eastern United States have transitioned to an alternative state of closed eastern broadleaf forests due to uncontrolled establishment of many tree species.

关键词： fire Historical Range of variability Transition

Risk Perception and Knowledge in fire Risk Reduction in a Dong Minority Rural Village in China: A Health-EDRM Education Intervention Study

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International Journal of Disaster Risk Science 2018年第3期9卷 306-318页

作者： Emily Ying Yang Chan Holly Ching Yu Lam Phoebe Pui Wun Chung Zhe Huang Tony Ka Chun Yung Kelvin Wai Kit Ling Gloria Kwong Wai Chan Cheuk Pong Chiu Collaborating Centre for Oxford University and CUHK for Disaster and Medical Humanitarian Response (CCOUC) The Chinese University of Hong Kong Nuffield Department of Medicine University of Oxford The Jockey Club School of Public Health and Primary Care The Chinese University of Hong Kong Franois-Xavier Bagnoud Center for Health and Human Rights Harvard University Integrated Research on Disaster Risk (IRDR) International Centre of Excellence–CCOUC (ICoE-CCOUC)

fire is one of the major disasters in rural communities but evidence of the effectiveness of education interventions against fire risks is limited. This was a 2-year study assessed the effectiveness of face-to-face Health Emergency and Disaster Risk Management(HealthEDRM) education interventions for raising fire risk reduction knowledge in a fire-prone rural ethnic minority community. The study was conducted in various pre-set time points of an intervention-based project in a Dongbased community in Nanjiang Village, Guizhou Province in 2015 and 2016 to increase knowledge among the villagers about how to reduce general-and electrical-fire risks. Pre-and post-intervention questionnaires were used to evaluate the effectiveness of increasing fire risk-related knowledge through these interventions, immediately after the 2015 and 2016 interventions, and 17 months after the 2015 intervention. The knowledge of using fire blanket,recalling the correct emergency telephone number,unplugging unused electrical appliances, and not using water to extinguish electrical fires had immediately improved after the interventions. Subjects demonstrated a better understanding that fire blankets can fight a blaze if used appropriately, and that knowledge was sustained for 17 months. The interventions were effective in improving fire prevention and response knowledge. Targeted interventions should be organized according to communities' culture, the evolution of economic prosperity and lifestyle practices.

关键词： Dong village fire risk education fire risk perception fire risk reduction Health education Rural China Health-EDRM

Nonparametric multivariate analysis of variance for affecting factors on the extent of forest fire damage in Jilin Province, China

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Journal of Forestry Research 2019年第6期30卷 2185-2197页

作者： Jing Li Yanlong Shan Sainan Yin Mingxia Wang Long Sun Daning Wang College of Mathematics and Statistics Beihua University3999 Binjiangdong RoadJilin 132013People’s Republic of China Forestry College Beihua University3999 Binjiangdong RoadJilin 132013People’s Republic of China College of Forestry Northeast Forestry University26 Hexing RoadHarbin 150040People’s Republic of China Changbai Mountain Forest Industry Group Corporation Limited of Jilin Province 99 Changbaishanxi RoadYanji 133000People’s Republic of China

Forest fires are influenced by several factors,including forest location,species type,age and density,date of fire occurrence,temperatures,and wind speeds,among others.This study investigates the quantitative effects of these factors on the degree of forest fire disaster using nonparametric statistical methods to provide a theoretical basis and data support for forest fire management.Data on forest fire damage from 1969 to 2013 was analyzed.The results indicate that different forest locations and types,fire occurrence dates,temperatures,and wind speeds were statistically significant.The eastern regions of the study area experienced the highest fire occurrence,accounting for 85.0%of the total number of fires as well as the largest average forested area burned.April,May,and October had more frequent fires than other months,accounting for 78.9%,while September had the most extensive forested area burned(63.08 ha)and burnt area(106.34 ha).Hardwood mixed forest and oak forest had more frequent fires,accounting for 31.9%and 26.0%,respectively.Hardwood-conifer mixed forest had the most forested area burned(50.18 ha)and burnt area(65.09 ha).Temperatures,wind speeds,and their interaction had significant impacts on forested area burned and area burnt.

关键词： Jilin Province Brown–Forsythe method Scheirer-Ray-Hare method Impact factors Forest fire damage

Short-term effects of fire disturbance on CH4 emission from forested wetlands in the Xiaoxing’an Mountains, Northeast China

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Journal of Forestry Research 2019年第3期30卷 969-979页

作者： Han Gu Wenyu Zheng Dawei Xu Changcheng Mu College of Architecture and Urban Planning Chongqing Jiaotong UniversityChongqing 40074People’s Republic of China Postdoctoral Program of Landscape Architecture Northeast Forestry UniversityHarbin 150040People’s Republic of China School of Forestry Northeast Forestry University Harbin 150040People’s Republic of China

Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) after fire disturbance in the Xiaoxing’an Mountains. The results showed the following: during the growing season, the annual CH4 emission distribution ranged from - 0.001 ± 0.012 to 22.373 ± 3.650 mg m^-2 h^-1;mild fire caused the swamp CH4 emission flux of tussock, shrub, Alnus sibirica and birch swamp to increase by 56.0–524.7%;at low water levels, temperature had a significant influence on the swamp type, and the correlation between the methane emission flux and temperature was significantly strengthened;after a fire disturbance, methane emissions from all types of marsh were highest in summer and second highest in autumn, with a weak absorption in spring;and along the water environment gradient of the transition zone, the CH4 emission flux presented a decreasing trend in its spatial distribution pattern.

关键词： Xiaoxing’an Mountains Forest swamp CH4 emission fire disturbance

Theoretical analysis and numerical simulation on behaviour properties of large span cable-supported structures under fire conditions

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Science China(Technological Sciences) 2009年第8期52卷 2340-2349页

作者： BAI Yin SHI YongJiu WANG YuanQing Department of Civil Engineering Key Laboratory of Structural Engineering and Vibration of China Education MinistryTsinghua UniversityBeijing 100084China

Large span cable-supported structures have been developed rapidly in China, and they always adopt high-strength steel cables as structural members. However, the modulus of elasticity and yield strength of steel material will decrease seriously under fire conditions while fire protection is unlikely to be provided for steel cable. Several typical large span cable-supported structures such as cable truss, beam string structure and prestressed cable net are studied on their structural behaviour in this paper. Theoretical formulae are derived in terms of geometrical and material nonlinearity with high temperature effect. Finite element models are also established to simulate the structural performance under fire conditions. The calculation formulae for fire-resisting design are suggested for these three types of structures, while displacement and prestressed force variation rules are also given.

关键词： cable-supported structure fire resisting design theoretical deriviation prestensioning force variation FEA model

Integration of satellite remote sensing data in underground coal fire detection:A case study of the Fukang region,Xinjiang,China

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Frontiers of Earth Science 2020年第1期14卷 1-12页

作者： Shiyong YAN Ke SHI Yi LI Jinglong LIU Hongfeng ZHAO Ministy of Natural Resource Key Lab of Land Environment and Disaster Monitoring China University of Mining and TechnologyXuzhou 221116China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Comprehensive Geological Exploration Team in Coal Geology Bureau of Xinjiang Uygur Autonomous Region Urumchi 830009China

Xinjiang in China is one of the areas worst affected by coal fires.Coal fires cannot only waste a large amount of natural resources and cause serious economic losses,but they also cause huge damage to the atmosphere,the soil,the surrounding geology,and the environment.Therefore,there is an urgent need to effectively explore remote sensing based detection of coal fires for timely understanding of their latest development trend.In this study,in order to investigate the distribution of coal fires in an accurate and reliable manner,we exploited both Landsat-8 optical data and Sentinel-1A synthetic aperture radar(SAR)images,using the generalized single-channel algorithm and the InSAR time-series analysis approach,respectively,for coal fire detection in the southern part of the Fukang region of Xinjiang,China.The generalized single-channel algorithm was used for land surface temperature information extraction.Meanwhile,the timeseries InSAR analysis technology was employed for estimating the surface micro deformation information,which was then used for building a band-pass filter.The suspected coal fire locations could then be established by a band-pass filtering operation on the obtained surface temperature map.Finally,the locations of the suspected coal fires were validated by the use of field survey data.The results indicate that the integration of thermal infrared remote sensing and radar interferometry technologies is an efficient investigation approach for coal fire detection in a large-scale region,which would provide the necessary spatial information support for the survey and control of coal fires.

关键词： land surface temperature generalized singlechannel algorithm surface deformation time-series InSAR analysis filtering operation coal fire detection