Journal of Environmental Science and Management, 2020
The crown fuel characteristics of the most dominant coniferous species in Korea, Pinus densiflora... more The crown fuel characteristics of the most dominant coniferous species in Korea, Pinus densiflora, were investigated in Gyeongbuk province, Korea. Allometric equations using DBH as independent variable were also developed for the estimation of crown fuel load (needles, branches: <0.5 cm, 0.5-1 cm, 1-2 cm, and 2-4 cm in diameter), crown volume, and aboveground biomass. The average crown bulk density in Youngju and Bonghwa was 0.47 kg m-3, while in Daegu, it was 0.29 kg m-3. The crown bulk density of needles and branches with a diameter of <1 cm was 0.21 kg m-3in Youngju, 0.27 kg m-3 in Bonghwa, and 0.13 kg m-3 in Daegu. The average crown base height was 5.10 m in Youngju, 5.20 m in Daegu, and 3.60 m in Bonghwa. Overall, the Pinus densiflora stand in Bonghwa is more hazardous if crown fire occurs compared to the other study sites based on different crown fuel characteristics. The allometric models developed were able to explain at least 79% of the observed variation in the bioma...
2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR), 2021
Multistatic synthetic aperture radar (SAR) is a SAR system consisted of multiple transmitters and... more Multistatic synthetic aperture radar (SAR) is a SAR system consisted of multiple transmitters and receivers. A multistatic SAR system is highly flexible in the selection of radar parameters compared to a monostatic SAR system. The image quality can be adjusted by controlling the parameters of a multistatic SAR system. In this paper, a multistatic SAR system is simulated where the distance between the satellites is varied. The numerical simulation assumed three satellites traveling in the along track configuration. One of the satellites was used as transmitter and receiver, and the others were used as receivers. The back-projection algorithm was modified to synthesize a radar image using multistatic SAR data. Multiple multistatic SAR with different distance between the satellites were simulated. The resolution and peak sidelobe ratio (PSLR) of multistatic SAR image were analyzed.
Journal of korean society of hazard mitigation, 2013
This study suggested the proper number of the forest fire surveillance cameras. The visualities a... more This study suggested the proper number of the forest fire surveillance cameras. The visualities and effectiveness of surveillance cameras were analyzed according to basic administrative units in Samcheok City. First, we assessed the visual range and effectiveness of each surveillance camera. The results showed that visibility of the seventh surveillance camera was narrow and overlapped because of short distance from other camera. Consequently, The results of these analysis shows that the cameras which had a poor visual range located must be relocated in area where that had a high visual range. As new surveillance cameras are installed in this region, the location of these would have to be considered by these conditions; the overlapping of visibility with other cameras or other organizations, the adequacy of its location, etc. And over 32 surveillance camera would be need for the most effective monitoring in Samcheok City. These results would be utilized for improving an efficiency of surveillance camera and forest fire management techniques.
To achieve the forest fire management goals such as early detection and quick suppression, fire r... more To achieve the forest fire management goals such as early detection and quick suppression, fire resources should be allocated at high probability area where forest fires occur. The objective of this study was to develop and validate models to estimate spatially distributed probabilities of occurrence of forest fire. The models were builded by exploring relationships between fire ignition location and forest, terrain and anthropogenic factors using logistic regression. Distance to forest, cemetery, fire history, forest type, elevation, slope were chosen as the significant factors to the model. The model constructed had a good fit and classification accuracy of the model was 63%. This model and map can support the allocation optimization of forest fire resources and increase effectiveness in fire prevention and planning.
Topography factors, as homeostasis variables at forest fire, affect the formation of fuel load pa... more Topography factors, as homeostasis variables at forest fire, affect the formation of fuel load patterns, atmospheric phenomena and forest fire behavior. Examination of the correlation between landforms and fire severity is important to decision making for fire hazard analysis and fighting strategies. In this study, fire severity was analyzed using Normalized Burn Ratio(NBR) derived from pre- and post-fire Landsat TM/+ETM images and landform were classified based on Topographic Position Index(TPI) in Samcheok(2000), Cheongyang(2002), and Yangyang(2005) forest fire regions. F-tests and Duncan's multi-range test between landform and fire severity showed that fire severities of headwater, high ridges, and upper slopes is higher than ones of local ridges, midslope ridges, and plains. Fire severity were more sensitive in coniferous forest than broadleaf forests.
Globally, the forest fires are a significant contributor of carbon dioxide and other greenhouse g... more Globally, the forest fires are a significant contributor of carbon dioxide and other greenhouse gases in the atmosphere. In this study, fuel load consumed by forest fire and emission of green house gases were analysed in the surface layer. For this, remaining fuel was collected and weighed with the species (Japanese red pine, deciduous) and the forest fire types (surface fire, crown fire) in the 51 forest fires. 8,361 kg/ha fuel load was consumed in deciduous forest damaged by surface fire, and 8,055 kg/ha, 12,333 kg/ha in Japanese red pine burned by surface fire and crown fire. The combustion ratios were 78, 59, and 90%, respectively. 15,856 kg/ha the green house gases such as , , in deciduous forest burned by surface fire was emitted and 14,834 kg/ha, 22,709 kg/ha in Japanese red pine burned by surface fire and crown fire.
Based on the landslide hazard scoring system of Korea Forest Research Institute, a GIS model for ... more Based on the landslide hazard scoring system of Korea Forest Research Institute, a GIS model for predicting landslide hazards was developed. The risk of landslide hazards was analyzed as the function of 7 environmental site factors for the terrain, vegetation, and geological characteristics of the corresponding forest stand sites. Among the environmental factors, slope distance, relative height and shapes of slopes were interpreted using the forestland slope interpretation module developed by Chung et al. (2002). The program consists of three modules for managing spatial data, analyzing landslide hazard and report-writing, A performance test of the model showed that 72% of the total landslides in Youngin-Ansung landslides area took place in the highly vulnerable zones of grade 1 or 2 of the landslide hazard scoring map.
In this study, the process of explosion has been simulated on a fire extinguishing bomb for the o... more In this study, the process of explosion has been simulated on a fire extinguishing bomb for the object of extinguishing wild forest fires with Sedov's similarity theory. As this problem consists of two-phase flow with the media of air and water in the regime of compressible flow, the direct numerical simulation is very difficult in the present model. Therefore, applying analytic similarity theory, the suitable parameter powers are obtained for the dimensional analysis. Through this investigation, the complex physical phenomena is simply analyzed with the similarity theory, and the result is expected to be applied usefully to the prediction of performance in fire extinguishing bombs.
Ventricular‐arterial coupling is the ratio of arterial elastance to ventricular end‐systolic elas... more Ventricular‐arterial coupling is the ratio of arterial elastance to ventricular end‐systolic elastance.
Journal of Korean Society of Hazard Mitigation, Jun 30, 2012
The facilities in the wildland-urban interface were main cause of forest fire occurrence and impo... more The facilities in the wildland-urban interface were main cause of forest fire occurrence and important point of forest fire protection and safety. The management of facilities and the determining the order of priorities for forest fire attack were very important for protecting human lifes and properties and estates. In this study, orders of danger rating priority and safety priority for facilities in wildland-urban interface were surveyed by questionnaire concerning. In results, the rate of awareness for danger facilities were high, while rate for protected facilities were low, The classification system for these facilities and education systems would be needed for solution of these problem. Officers who worked in the forest part(national and local administration) recognized rice paddies and dry fields, graveyards and orchard as danger facilities. And they recognized cultural assets and a preserved forest as protected facilities. The cultural assets and houses would be recognized as principal damaged facilities.
In this research, climate classification maps over the Korean Peninsula at 1 km resolution were g... more In this research, climate classification maps over the Korean Peninsula at 1 km resolution were generated using the satellite-based climatic variables of monthly temperature and precipitation based on machine learning approaches. Random forest (RF), artificial neural networks (ANN), k-nearest neighbor (KNN), logistic regression (LR), and support vector machines (SVM) were used to develop models. Training and validation of these models were conducted using in-situ observations from the Korea Meteorological Administration (KMA) from 2001 to 2016. The rule of the traditional Kö ppen-Geiger (K-G) climate classification was used to classify climate regions. The input variables were land surface temperature (LST) of the Moderate Resolution Imaging Spectroradiometer (MODIS), monthly precipitation data from the Tropical Rainfall Measuring Mission (TRMM) 3B43 product, and the Digital Elevation Map (DEM) from the Shuttle Radar Topography Mission (SRTM). The overall accuracy (OA) based on validation data from 2001 to 2016 for all models was high over 95%. DEM and minimum winter temperature were two distinct variables over the study area with particularly high relative importance. ANN produced more realistic spatial distribution of the classified climates despite having a slightly lower OA than the others. The accuracy of the models using high altitudinal in-situ data of the Mountain Meteorology Observation System (MMOS) was also assessed. Although the data length of the MMOS data was relatively short (2013 to 2017), it proved that the snowy, dry and cold winter and cool summer class (Dwc) is widely located in the eastern coastal region of South Korea. Temporal shifting of climate was examined through a comparison of climate maps produced by period: from 1950 to 2000, from 1983 to 2000, and from 2001 to 2013. A shrinking trend of snow classes (D) over the Korean Peninsula was clearly observed from the ANN-based climate classification results. Shifting trends of climate with the decrease/increase of snow (D)/temperate (C) classes were clearly shown in the maps produced using the proposed approaches, consistent with the results from the reanalysis data of the Climatic Research Unit (CRU) and Global Precipitation Climatology Centre (GPCC).
Journal of the Korean Society of Hazard Mitigation, 2019
The objective of this study is to predict the effects of forest management activities on canopy f... more The objective of this study is to predict the effects of forest management activities on canopy fuel characteristics for Pinus koraiensis stands. We used data from 136 managed stands and 23 unmanaged stands of the National Forest Inventory for this study. Weibull function and mortality models were developed. A dynamic growth model in which models were interactively linked was prepared to predict stand growth and forest fuel loads after considering the mortality rate. As a result, after 20 years of managed stand data, the increase in available canopy fuel load was predicted to be about 12.8 ton/ha and increase in available canopy bulk density was predicted to be about 0.2kg/㎥. However, the increase in available canopy fuel load for unmanaged stands was about 15.2 ton/ha and the increase in available canopy bulk density was about 0.3 kg/㎥. These results showed that there were higher forest fuel loads in unmanaged stands than in managed stands. The risk of crown fire hazard is higher, and the forest fire hazard of unmanaged stands is judged to be higher than that of managed stands of Pinus koraiensis species in South Korea.
This study explores the tradeoff relationship between the number of initial attack firefighting r... more This study explores the tradeoff relationship between the number of initial attack firefighting resources and the level of fire ignition prevention efforts mitigating the probability of human-made fires in the Republic of Korea, where most fires are caused by human activities. To examine this tradeoff relationship, we develop a hybrid model that combines a robust optimization model with a stochastic simulation model. The robust optimization minimizes the expected number of fires not receiving a pre-defined response, such as the number of firefighting resources that must arrive at the fire within half an hour, subject to budget constraints and uncertainty about the daily number and location of fires. The simulation model produces a set of fire scenarios in which a combination of number, location, ignition time, and intensity of fires occur. Results show that fire ignition prevention is as cost-effective as initial attack firefighting resources given the current budget in the Republic of Korea for reducing the expected number of fires not covered by the predefined response. The mixed policy of fire suppression and fire prevention may produce some gains in efficiency relative to the dominant policy of strong fire suppression strategies.
Journal of the Korean Society of Hazard Mitigation, 2018
The objective of this study were to analyze the characteristics of surface and crown fuel and to ... more The objective of this study were to analyze the characteristics of surface and crown fuel and to compare the hazard of crown fire transition and spread in the Costal type Pinus thunbergii and Inland type Pinus thunbergii. 25 surface fuel of each type were sampled and 10 trees of each type were destructively sampled to analyze crown fuel characteristic. The results of this study showed that the Inland type has higher surface moisture content due to the difference in crown cover, although the two types showed similar crown moisture content. Inland type (42.7%) has more crown needles than Coastal type (33.8%). The ratio of available crown fuel was 59.2% of Inland type and 57.2% of Coastal type. The adjusted coefficients of determination ( ) values were high (more than 0.850) or more except for thick branches of more than 1cm. The available canopy bulk density of Inland type was 1.29 times higher despite the smaller canopy volume.
Journal of Environmental Science and Management, 2020
The crown fuel characteristics of the most dominant coniferous species in Korea, Pinus densiflora... more The crown fuel characteristics of the most dominant coniferous species in Korea, Pinus densiflora, were investigated in Gyeongbuk province, Korea. Allometric equations using DBH as independent variable were also developed for the estimation of crown fuel load (needles, branches: <0.5 cm, 0.5-1 cm, 1-2 cm, and 2-4 cm in diameter), crown volume, and aboveground biomass. The average crown bulk density in Youngju and Bonghwa was 0.47 kg m-3, while in Daegu, it was 0.29 kg m-3. The crown bulk density of needles and branches with a diameter of <1 cm was 0.21 kg m-3in Youngju, 0.27 kg m-3 in Bonghwa, and 0.13 kg m-3 in Daegu. The average crown base height was 5.10 m in Youngju, 5.20 m in Daegu, and 3.60 m in Bonghwa. Overall, the Pinus densiflora stand in Bonghwa is more hazardous if crown fire occurs compared to the other study sites based on different crown fuel characteristics. The allometric models developed were able to explain at least 79% of the observed variation in the bioma...
2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR), 2021
Multistatic synthetic aperture radar (SAR) is a SAR system consisted of multiple transmitters and... more Multistatic synthetic aperture radar (SAR) is a SAR system consisted of multiple transmitters and receivers. A multistatic SAR system is highly flexible in the selection of radar parameters compared to a monostatic SAR system. The image quality can be adjusted by controlling the parameters of a multistatic SAR system. In this paper, a multistatic SAR system is simulated where the distance between the satellites is varied. The numerical simulation assumed three satellites traveling in the along track configuration. One of the satellites was used as transmitter and receiver, and the others were used as receivers. The back-projection algorithm was modified to synthesize a radar image using multistatic SAR data. Multiple multistatic SAR with different distance between the satellites were simulated. The resolution and peak sidelobe ratio (PSLR) of multistatic SAR image were analyzed.
Journal of korean society of hazard mitigation, 2013
This study suggested the proper number of the forest fire surveillance cameras. The visualities a... more This study suggested the proper number of the forest fire surveillance cameras. The visualities and effectiveness of surveillance cameras were analyzed according to basic administrative units in Samcheok City. First, we assessed the visual range and effectiveness of each surveillance camera. The results showed that visibility of the seventh surveillance camera was narrow and overlapped because of short distance from other camera. Consequently, The results of these analysis shows that the cameras which had a poor visual range located must be relocated in area where that had a high visual range. As new surveillance cameras are installed in this region, the location of these would have to be considered by these conditions; the overlapping of visibility with other cameras or other organizations, the adequacy of its location, etc. And over 32 surveillance camera would be need for the most effective monitoring in Samcheok City. These results would be utilized for improving an efficiency of surveillance camera and forest fire management techniques.
To achieve the forest fire management goals such as early detection and quick suppression, fire r... more To achieve the forest fire management goals such as early detection and quick suppression, fire resources should be allocated at high probability area where forest fires occur. The objective of this study was to develop and validate models to estimate spatially distributed probabilities of occurrence of forest fire. The models were builded by exploring relationships between fire ignition location and forest, terrain and anthropogenic factors using logistic regression. Distance to forest, cemetery, fire history, forest type, elevation, slope were chosen as the significant factors to the model. The model constructed had a good fit and classification accuracy of the model was 63%. This model and map can support the allocation optimization of forest fire resources and increase effectiveness in fire prevention and planning.
Topography factors, as homeostasis variables at forest fire, affect the formation of fuel load pa... more Topography factors, as homeostasis variables at forest fire, affect the formation of fuel load patterns, atmospheric phenomena and forest fire behavior. Examination of the correlation between landforms and fire severity is important to decision making for fire hazard analysis and fighting strategies. In this study, fire severity was analyzed using Normalized Burn Ratio(NBR) derived from pre- and post-fire Landsat TM/+ETM images and landform were classified based on Topographic Position Index(TPI) in Samcheok(2000), Cheongyang(2002), and Yangyang(2005) forest fire regions. F-tests and Duncan's multi-range test between landform and fire severity showed that fire severities of headwater, high ridges, and upper slopes is higher than ones of local ridges, midslope ridges, and plains. Fire severity were more sensitive in coniferous forest than broadleaf forests.
Globally, the forest fires are a significant contributor of carbon dioxide and other greenhouse g... more Globally, the forest fires are a significant contributor of carbon dioxide and other greenhouse gases in the atmosphere. In this study, fuel load consumed by forest fire and emission of green house gases were analysed in the surface layer. For this, remaining fuel was collected and weighed with the species (Japanese red pine, deciduous) and the forest fire types (surface fire, crown fire) in the 51 forest fires. 8,361 kg/ha fuel load was consumed in deciduous forest damaged by surface fire, and 8,055 kg/ha, 12,333 kg/ha in Japanese red pine burned by surface fire and crown fire. The combustion ratios were 78, 59, and 90%, respectively. 15,856 kg/ha the green house gases such as , , in deciduous forest burned by surface fire was emitted and 14,834 kg/ha, 22,709 kg/ha in Japanese red pine burned by surface fire and crown fire.
Based on the landslide hazard scoring system of Korea Forest Research Institute, a GIS model for ... more Based on the landslide hazard scoring system of Korea Forest Research Institute, a GIS model for predicting landslide hazards was developed. The risk of landslide hazards was analyzed as the function of 7 environmental site factors for the terrain, vegetation, and geological characteristics of the corresponding forest stand sites. Among the environmental factors, slope distance, relative height and shapes of slopes were interpreted using the forestland slope interpretation module developed by Chung et al. (2002). The program consists of three modules for managing spatial data, analyzing landslide hazard and report-writing, A performance test of the model showed that 72% of the total landslides in Youngin-Ansung landslides area took place in the highly vulnerable zones of grade 1 or 2 of the landslide hazard scoring map.
In this study, the process of explosion has been simulated on a fire extinguishing bomb for the o... more In this study, the process of explosion has been simulated on a fire extinguishing bomb for the object of extinguishing wild forest fires with Sedov's similarity theory. As this problem consists of two-phase flow with the media of air and water in the regime of compressible flow, the direct numerical simulation is very difficult in the present model. Therefore, applying analytic similarity theory, the suitable parameter powers are obtained for the dimensional analysis. Through this investigation, the complex physical phenomena is simply analyzed with the similarity theory, and the result is expected to be applied usefully to the prediction of performance in fire extinguishing bombs.
Ventricular‐arterial coupling is the ratio of arterial elastance to ventricular end‐systolic elas... more Ventricular‐arterial coupling is the ratio of arterial elastance to ventricular end‐systolic elastance.
Journal of Korean Society of Hazard Mitigation, Jun 30, 2012
The facilities in the wildland-urban interface were main cause of forest fire occurrence and impo... more The facilities in the wildland-urban interface were main cause of forest fire occurrence and important point of forest fire protection and safety. The management of facilities and the determining the order of priorities for forest fire attack were very important for protecting human lifes and properties and estates. In this study, orders of danger rating priority and safety priority for facilities in wildland-urban interface were surveyed by questionnaire concerning. In results, the rate of awareness for danger facilities were high, while rate for protected facilities were low, The classification system for these facilities and education systems would be needed for solution of these problem. Officers who worked in the forest part(national and local administration) recognized rice paddies and dry fields, graveyards and orchard as danger facilities. And they recognized cultural assets and a preserved forest as protected facilities. The cultural assets and houses would be recognized as principal damaged facilities.
In this research, climate classification maps over the Korean Peninsula at 1 km resolution were g... more In this research, climate classification maps over the Korean Peninsula at 1 km resolution were generated using the satellite-based climatic variables of monthly temperature and precipitation based on machine learning approaches. Random forest (RF), artificial neural networks (ANN), k-nearest neighbor (KNN), logistic regression (LR), and support vector machines (SVM) were used to develop models. Training and validation of these models were conducted using in-situ observations from the Korea Meteorological Administration (KMA) from 2001 to 2016. The rule of the traditional Kö ppen-Geiger (K-G) climate classification was used to classify climate regions. The input variables were land surface temperature (LST) of the Moderate Resolution Imaging Spectroradiometer (MODIS), monthly precipitation data from the Tropical Rainfall Measuring Mission (TRMM) 3B43 product, and the Digital Elevation Map (DEM) from the Shuttle Radar Topography Mission (SRTM). The overall accuracy (OA) based on validation data from 2001 to 2016 for all models was high over 95%. DEM and minimum winter temperature were two distinct variables over the study area with particularly high relative importance. ANN produced more realistic spatial distribution of the classified climates despite having a slightly lower OA than the others. The accuracy of the models using high altitudinal in-situ data of the Mountain Meteorology Observation System (MMOS) was also assessed. Although the data length of the MMOS data was relatively short (2013 to 2017), it proved that the snowy, dry and cold winter and cool summer class (Dwc) is widely located in the eastern coastal region of South Korea. Temporal shifting of climate was examined through a comparison of climate maps produced by period: from 1950 to 2000, from 1983 to 2000, and from 2001 to 2013. A shrinking trend of snow classes (D) over the Korean Peninsula was clearly observed from the ANN-based climate classification results. Shifting trends of climate with the decrease/increase of snow (D)/temperate (C) classes were clearly shown in the maps produced using the proposed approaches, consistent with the results from the reanalysis data of the Climatic Research Unit (CRU) and Global Precipitation Climatology Centre (GPCC).
Journal of the Korean Society of Hazard Mitigation, 2019
The objective of this study is to predict the effects of forest management activities on canopy f... more The objective of this study is to predict the effects of forest management activities on canopy fuel characteristics for Pinus koraiensis stands. We used data from 136 managed stands and 23 unmanaged stands of the National Forest Inventory for this study. Weibull function and mortality models were developed. A dynamic growth model in which models were interactively linked was prepared to predict stand growth and forest fuel loads after considering the mortality rate. As a result, after 20 years of managed stand data, the increase in available canopy fuel load was predicted to be about 12.8 ton/ha and increase in available canopy bulk density was predicted to be about 0.2kg/㎥. However, the increase in available canopy fuel load for unmanaged stands was about 15.2 ton/ha and the increase in available canopy bulk density was about 0.3 kg/㎥. These results showed that there were higher forest fuel loads in unmanaged stands than in managed stands. The risk of crown fire hazard is higher, and the forest fire hazard of unmanaged stands is judged to be higher than that of managed stands of Pinus koraiensis species in South Korea.
This study explores the tradeoff relationship between the number of initial attack firefighting r... more This study explores the tradeoff relationship between the number of initial attack firefighting resources and the level of fire ignition prevention efforts mitigating the probability of human-made fires in the Republic of Korea, where most fires are caused by human activities. To examine this tradeoff relationship, we develop a hybrid model that combines a robust optimization model with a stochastic simulation model. The robust optimization minimizes the expected number of fires not receiving a pre-defined response, such as the number of firefighting resources that must arrive at the fire within half an hour, subject to budget constraints and uncertainty about the daily number and location of fires. The simulation model produces a set of fire scenarios in which a combination of number, location, ignition time, and intensity of fires occur. Results show that fire ignition prevention is as cost-effective as initial attack firefighting resources given the current budget in the Republic of Korea for reducing the expected number of fires not covered by the predefined response. The mixed policy of fire suppression and fire prevention may produce some gains in efficiency relative to the dominant policy of strong fire suppression strategies.
Journal of the Korean Society of Hazard Mitigation, 2018
The objective of this study were to analyze the characteristics of surface and crown fuel and to ... more The objective of this study were to analyze the characteristics of surface and crown fuel and to compare the hazard of crown fire transition and spread in the Costal type Pinus thunbergii and Inland type Pinus thunbergii. 25 surface fuel of each type were sampled and 10 trees of each type were destructively sampled to analyze crown fuel characteristic. The results of this study showed that the Inland type has higher surface moisture content due to the difference in crown cover, although the two types showed similar crown moisture content. Inland type (42.7%) has more crown needles than Coastal type (33.8%). The ratio of available crown fuel was 59.2% of Inland type and 57.2% of Coastal type. The adjusted coefficients of determination ( ) values were high (more than 0.850) or more except for thick branches of more than 1cm. The available canopy bulk density of Inland type was 1.29 times higher despite the smaller canopy volume.
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