• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.426-441
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• 2023

This study investigated the predictive accuracy of a model of landslide displacement in Jecheon-si, where a great number of landslides were triggered by heavy rain on both natural (non-clear-cut) and clear-cut slopes during August 2020. This was accomplished by applying three flow direction methods (single flow direction, SFD; multiple flow direction, MFD; infinite flow direction, IFD) and the degree of root cohesion to an infinite slope stability equation. The application assumed that the soil saturation and any changes in root cohesion occurred following the timber harvest (clear-cutting). In the study area, 830 landslide locations were identified via landslide inventory mapping from satellite images and 25 cm resolution aerial photographs. The results of the landslide modeling comparison showed the accuracy of the models that considered changes in the root cohesion following clear-cutting to be improved by 1.3% to 2.6% when compared with those not considered in the area under the receiver operating characteristics (AUROC) analysis. Furthermore, the accuracy of the models that used the MFD algorithm improved by up to 1.3% when compared with the models that used the other algorithms in the AUROC analysis. These results suggest that the discriminatory application of the root cohesion, which considers changes in the vegetation condition, and the selection of the flow direction method may influence the accuracy of landslide predictive modeling. In the future, the results of this study should be verified by examining the root cohesion and its dynamic changes according to the tree species using the field hydrological monitoring technique.

• Spatial Information Research
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• v.8 no.1
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• pp.85-99
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• 2000

Accurate information on habitat distribution of protected fauna is essential for the habitat management of Korea, a country with very high development pressure. The objectives of this study were to develop a habitat suitability model of wild boar based on GIS and logistic regression, and to create habitat distribution map, and to prepare the basis for habitat management of our country s endangered and protected species. The modeling process of this restudyarch had following three steps. First, GIS database of environmental factors related to use and availability of wild boar habitat were built. Wild boar locations were collected by Radio-Telemetry and GPS. Second, environmental factors affecting the habitat use and availability of wild boars were identified through chi-square test. Third, habitat suitability model based on logistic regression were developed, and the validity of the model was tested. Finally , habitat assessment map was created by utilizing a rule-based approach. The results of the study were as folos. First , distinct difference in wild boar habitat use by season and habitat types were found, however, no difference in wild boar habiat use by season and habitat types were found , however, ho difference by sex and activity types were found. Second, it was found, through habitat availability analysis, that elevation , aspect , forest type, and forest age were significant natural environmental factors affecting wild boar hatibate selection, but the effects of slope, ridge/valley, water, and solar radiation could not be identified, Finally, the habitat at cutoff value of 0.5. The model validation showed that inside validation site had the classification accuracy of 73.07% for total habitat and 80.00% for cover habitat , and outside validation site had the classification accuracy of 75.00% for total habitat.

• Journal of the Korean Geographical Society
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• v.43 no.5
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• pp.715-727
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• 2008

This study analyzed changes on the best condition of temperature and relative humidity for making artificial snows in the Yongpyong Ski Resort using data from Daegwallyeong. Depth of snowfall and snowfall days have decrease since 1990s. If the Yongpyong Ski Resort has only to depend on natural snows, it would be difficult to make and maintain ski slope. There are two times of snowmaking during ski seasons: one is the first snowmaking (October-November) for opening ski slopes and the other is the reinforcement of snowmaking (December-March) for maintaining snow quality during the seasons. Days having the best condition for the first snowmaking (daily minimum temperature below $-1^{\circ}C$ and daily average relative humidity 60 to 80 percent) decreased after 1970s. Days having the best condition for the reinforcement of snowmaking also decreased. While temperature changes are more evident than humidity changes for the first snowmaking, humidity changes are more obvious than change of temperature for the reinforcement of snowmaking. In the future climate projection by A1B scenarios, the length of ski seasons projected to decrease a 10 to 40 percent against the period of 1973-2008. The climate condition for the snowmaking projected to be poor, especially the due to increase of temperature.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.94-106
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• 2008

As populations inhabiting in natural ecosystem are fragmented by artificial barriers and habitats are destructed by development, extinction possibility of species is getting higher. It is necessary to design and to manage conservation areas and corridors considering animals' movement and migration for sustainable species diversity in present circumstances. 'Least-cost modeling' is one commonly employed approach in which dispersal costs are assigned to distinct habitat types and the last-costly dispersal paths among habitat patches are calculated using a geographical information system (GIS). This study aims to design ecological corridor using least-cost path method and to apply it to a regional ecological network considering movability of medium-large size mammals. This study was carried out over the metropolitan area, which has been deforested by rapid urbanization. Nevertheless there is connected with Gangwon province, Baekdudaegan mountain range and DMZ, considered where many forest species can migrate to this region. This study employs such an approach to develop least-cost path models for medium-large size mammals, have inhabited for this entire region. Considering those species, two forest areas as a source of species supply and forest areas more than 1,000ha are selected as focal forest areas. Movement and migration paths from species supply sources to focal forest areas are calculated by applying landscape permeability theory using land cover map, road density map and land slope map. Results showed least-cost paths from species supply sources to focal forest areas on two species. Wildcat and roe deer are different in some least-cost paths caused by their landscape permeability but paths show generally same specifics. The result of considering regional distribution of expected movement and migration paths to regional ecological network, low altitude mountains of western metropolitan area are evaluated important area for species connectivity. In national or regional levels ecological connectivity is essential to promote species diversity and to preserve integrated ecosystem. This study concludes that developing least-cost models from similar empirical data could significantly improve the utility of these tools.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.323-330
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• 1998

Tetrahydroisoquinoline (THI) alkaloids can be considered as cyclized derivatives of simple phenylethylamines. Many of them, especially with 6,7-disubstitution, demonstrate a relatively high affinity for catecholamines. Present study examines the pharmacological action of limited series of THI, using rats' isolated atria and aorta. In addition, a $[^3H]$ prazosin displacement binding study with THI compounds was performed, using rat brain homogenates to investigate whether these probes have ?${\alpha}$-adrenoceptor affinity. We also compared the vascular relaxation potency of these probes with dobutamine. YS 49, YS 51, higenamine and dobutamine, concentration-dependently, relaxed endothelium-denuded rat thoracic aorta precontracted with phenylephrine (PE, 0.1 ${\mu}M$) in which $pEC_{50}$ were $5.56{\pm}0.32$ and $5.55{\pm}0.21$, $5.99{\pm}1.16$ and $5.57{\pm}0.34$, respectively. These probes except higenamine also relaxed KCl (65.4 mM)-contracted aorta. In isolated rat atria, all THIs and dobutamine increased heart rate and contractile force. In the presence of propranolol, the concentration response curves of YS 49 and YS 51 shifted to the right and resulted in $pA_2$ values of $8.07{\pm}0.84$ and $7.93{\pm}0.11$, respectively. The slope of each compound was not deviated from unity, indicating that these chemicals are highly competitive at the cardiac ?${\beta}-adrenoceptors$. YS 49, YS 51, and higenamine showed ?${\alpha)-adrenoceptor$ affinity in rat brain, in which the dissociation constant $(K_i)$ was 2.75, 2.81, and 1.02 ${\mu}M$, respectively. It is concluded, therefore, that THI alkaloids have weak affinity to ${\alpha)_1-adrenoceptor$ in rat aorta and brain, respectively, while these probes show relatively high affinity for cardiac ${\beta}-adrenoceptors$. Thus, these chemicals may be useful in the treatment of congestive heart failure.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.228-241
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• 1989

The objectives of this study are to identify flood disasters resulted from heavy rainstorm including earth and stone-debris avalanches and also to develope the scientific data to be needed for establishing the landslide-related disaster prevention countermeasures. For this study, 5 Gun (district) regions including Booyeo, Seochun, Gongju, Boryung, and Chungyang in Chungchongnam-do of the central part of Korea, in which severe landslide damages have been triggered during 3 days from July 21 to July 23, 1987, were investigated. Mostly, landslides having death of human lives triggered from 6 a.m, to 8 a,m. on July 22, and the principal factor was proved to be the continuous heavy rain ; the continuous rainfall of internal region for 3 days measured about 300-673 mm. The structural measures for slope failure prevention countermeasures at the hollow part of upper hillslope should be required. Natural drainage network on slopes should not be disturbed in case of land use alteration, such as a chestnut planting work on hillslopes behind the houses particularly. There are so many problems in recognition of landslide disaster prevention countermeasures including evacuation exercises. More actual education of countermeasures for control of flood and landslide should be put to practice through "civil defense education" and "inhabitants' meeting." In this context, existing Erosion Control Stations of 13 regions established in each Province should not be reduced. The designation criterion and surveying processes of "Landslide Prone Site" published by Forest Administration should also be improved scientifically.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1277-1290
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• 2020

Water resources which is formed of surface and groundwater, are considered as one of the pivotal natural resources worldwide. Since last century, the rapid population growth as well as accelerated industrialization and explosive urbanization lead to boost demand for groundwater for domestic, industrial and agricultural use. In fact, better management of groundwater can play crucial role in sustainable development; therefore, determining accurate location of groundwater based groundwater potential mapping is indispensable. In recent years, integration of machine learning techniques, Geographical Information System (GIS) and Remote Sensing (RS) are popular and effective methods employed for groundwater potential mapping. For determining the status of the integrated approach, a systematic review of 94 directly relevant papers were carried out over the six previous years (2015-2020). According to the literature review, the number of studies published annually increased rapidly over time. The total study area spanned 15 countries, and 85.1% of studies focused on Iran, India, China, South Korea, and Iraq. 20 variables were found to be frequently involved in groundwater potential investigations, of which 9 factors are almost always present namely slope, lithology (geology), land use/land cover (LU/LC), drainage/river density, altitude (elevation), topographic wetness index (TWI), distance from river, rainfall, and aspect. The data integration was carried random forest, support vector machine and boost regression tree among the machine learning techniques. Our study shows that for optimal results, groundwater mapping must be used as a tool to complement field work, rather than a low-cost substitute. Consequently, more study should be conducted to enhance the generalization and precision of groundwater potential map.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.80-96
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• 2023

The expansion of human activities and road development has led to the loss and fragmentation of ecological spaces, which is a negative factor for biodiversity. In particular, urban areas where land use and land cover have rapidly changed into urbanization zones are regions where ecological spaces are lost and isolated, making it difficult for wildlife to inhabit. Furthermore, the loss and fragmentation of ecological spaces due to urbanization can have a negative impact on ecosystem services. Therefore, to enhance biodiversity and ecosystem services in urban and national land, it is necessary to establish a practical ecological axis that reflects the current status of the city. Thus, this study analyzed the connectivity of ecological spaces and forest axis that can be used for spatial planning related to urban ecological axis of local governments in Daegu and Gyeongsangbuk-do. The ecological connectivity was analyzed by dividing the Daegu-Gyeongbuk region into 31 local government units, distinguishing between forests and natural areas using land cover data. Subsequently, the study area was divided into 20,483 hexagonal grids of 1 square kilometer each, and the restoration effects for ecological fragmentation within 100 meters were spatially clustered to visualize priority restoration areas. The forest axis was derived by considering regional conditions such as land cover, building area, slope, and others to connect 1,534 forests of 100 hectares or more. The research results are expected to be used as fundamental data for spatial planning, goal setting, and the selection of restoration areas for improving ecological connectivity.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.2
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• pp.34-44
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• 2024

Recently, due to abnormal climate caused by climate change, natural disasters such as floods, landslides, and soil outflows are rapidly increasing. In Korea, more than 63% of the land is vulnerable to slope disasters due to the geographical characteristics of mountainous areas, and in particular, Quarry mines soil and rocks, so there is a high risk of landslides not only inside the workplace but also outside.Accordingly, this study built a DEM using UAV and aviation LiDAR for monitoring the quarry, conducted a time series change analysis, and proposed an optimal DEM construction method for monitoring the soil collection site. For DEM construction, UAV and LiDAR-based Point Cloud were built, and the ground was extracted using three algorithms: Aggressive Classification (AC), Conservative Classification (CC), and Standard Classification (SC). UAV and LiDAR-based DEM constructed according to the algorithm evaluated accuracy through comparison with digital map-based DEM.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.651-660
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• 2007

Acid drainage has been recognized as an environmental concern in abandoned mine sites for long time. Recently, the environmental and structural damage by acid drainage is a current issue in construction sites in Korea. Here, the author introduces the type of damages by acid drainage in construction sites and emphasizes the importance of geoscience discipline in solving the problem. Metasedimentary rock of Okcheon group, coal bed of Pyeongan group, Mesozoic volcanic rock. and Tertiary sedimentary and volcanic rocks are the major rock types with a high potential for acid drainage upon excavation in Korea. The acid drainage causes the acidification and heavy metal contamination of soil, surface water and groundwater, the reduction of slope stability, the corrosion of slope structure, the damage on plant growth, the damage on landscape and the deterioration of concrete and asphalt pavement. The countermeasure for acid drainage is the treatment of acid drainage and the prevention of acid drainage. The treatment of acid drainage can be classified into active and passive treatments depending on the degree of natural process in the treatment. Removal of oxidants, reduction of oxidant generation and encapsulation of sulfide are employed for the prevention of acid drainage generation.