• Economic and Environmental Geology
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• v.50 no.3
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• pp.239-250
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• 2017

Physically based landslide susceptibility analysis has been recognized as an effective analysis method because it can consider the mechanism of landslide occurrence. The physically based analysis used the slope geometry and geotechnical properties of slope materials as input. However, when the physically based approach is adopted in regional scale area, the uncertainties were involved in the analysis procedure due to spatial variation and complex geological conditions, which causes inaccurate analysis results. Therefore, probabilistic method have been used to quantify these uncertainties. However, the uncertainties caused by lack of information are not dealt with the probabilistic analysis. Therefore, fuzzy set theory was adopted in this study because the fuzzy set theory is more effective to deal with uncertainties caused by lack of information. In addition, the vertex method and Monte Carlo simulation are coupled with the fuzzy approach. The proposed approach was used to evaluate the landslide susceptibility for a regional study area. In order to compare the analysis results of the proposed approach, Monte Carlo simulation as the probabilistic analysis and the deterministic analysis are used to analyze the landslide susceptibility for same study area. We found that Fuzzy Monte Carlo simulation showed the better prediction accuracy than the probabilistic analysis and the deterministic analysis.

• Journal of Environmental Impact Assessment
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• v.31 no.5
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• pp.321-333
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• 2022

In this study, the concentration and distribution characteristics of BTEX (benzene toluene, ethylbenzene, and xylene) emitted from Daesan Petrochemical Industrial Complex were examined to determine their potential hazards to local residents. Residents living nearby the complex areas may be exposed to the chemicals through various media (air, water, and soil), especially by air. This study evaluated human health risks by inhalation using both deterministic and probabilistic risk assessment approaches. As a result of the deterministic risk assessment, the non-cancer risk was much lower than the regulation limit of hazard index (HI 1.0) for all the points. However, in case of cancer risk evaluation, it was found that the risk of excess cancer for benzene at point A located in the industrial complex was 2.28×10^-6, which slightly exceeded the standard regulatory limit of 1.0×10^-6. In addition, the probabilistic risk assessment revealed that the percentile exceeding the standard of 1.0×10^-6was found to be 45.3%. The sensitivity analysis showed that exposure time (ET) had the greatest impact on the results. Based on the risk assessment study, it implied that ethylbenzene, toluene, and xylene had little adverse effects on potential human exposure, but benzene often exceeded the cancer risk standard (1.0×10^-6). Further studies on extensive VOCs monitoring are needed to evaluate the potential risks of industrial complex areas.

• Journal of the Korean association of regional geographers
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• v.14 no.1
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• pp.1-18
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• 2008

If there is no choice but to be urbanized, we should examine how human interference has had influences on the area to keep the river environment safe and stable. This study is aimed at finding improvement by examining the effect of human interference in Gapcheon river in Daejeon, which is developing fast. Distinctive features of human interference in Gapcheon river are followings. First, middle and upper reaches of Gapcheon river are being maintained and restored focusing on flood control but are scheduled to develop city and channel. Second, the rear area of middle and lower reaches of Gapcheon river is already developed into an urban district and solidified into artificial stream for leisure activities installing the artificial structure for fun. Third, lower reaches of Gapcheon river are in an unstable condition because of straightening waterway and developing rear area of river. Up to now, geographical features and bio-diversity of Gapcheon river has been ruined by the artificial management of river centered for technical engineering. From now on, followings should be considered for management of urban river. First, it is focused on maintaining eco system by itself than usage for human. Second, natural features of rear area of river should be taken into consideration and should be preserved before developing urban city and hills, back marsh, channel deposit and swamp to directly have an influence on river.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.312-322
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• 1999

We have studied both submarine morphology and sediment characteristics of waste disposal sites in the southwestern Ulleung Basin, East Sea, as part of a marine environmental preservation program. The Jung waste disposal site in the outer shelf is characterized by the thick accumulation of coarse-grained palimpsest sediments and fine-grained sediments from various sources. The Byung waste disposal site in the continental slope is generally characterized by hemipelagic muds with intermittent sandy sediments originated from the outer shelf and upper slope. The hemipelagic sediments, draping the seafloor, consist of fluidized muds. The core sediments show numerous bioturbation structures which cause vertical mixing of sediments. The surface sediments can be divided into four sand types (S-1, S-2, S-3, and S-4) and two mud types (M-1 and M-2) based on relative contents of reworked coarse-grained palimpsest sediments and fine-grained sediments. sorting and heavy mineral contents. The sands are probably relict sediments reworked during high-energy conditions such as typoon or storm. On the other hand, the muds were originated from various sources such as recent input from the Nakdong River, reworked fine-grained sediment from the shelf or suspended particulate matter from the East Sea Warm Current.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.3
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• pp.83-92
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• 2004

A continuous monitoring of textural characteristics of surface sediments, sedimentation rates and beach profile was carried out to investigate the seasonal variations of sedimentary processes in the Imjado beach, southwestern coast of Korea for two years. The beach profiles consist of steep beach face and relatively flat middle and low tide beaches. The slope of the beach face increases in summer and decreases in winter, in good accordance with the standard beach cycle. Ridge and runnel systems are well developed in the middle and low tide beaches during the summer, but these structures are replaced by mega-ripples during the winter. The sediments are fining southward as well as landward. The mean grain-size tends to be increasingly coarser during seasons of autumn and winter on the north beach and during seasons of winter and spring on the south one. In addition, the sediments are eroded on the north beach and accumulated on the south one as a whole. These are probably due to southward transportation of the sediments as long-shore current (NE-SW) runs around the coastal line of the beach. However, the seasonal variations in accumulation rates are very complex and irregular. It is considered that the Imjado beach represents in non-equilibrium state, as a result of coastal and submarine topographic changes by artificial agents and sea-level uprising associated with global warming.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.1
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• pp.30-35
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• 2003

The study of the scars formed on the bark of pine trees damaged by forest fire was carried out in the burned area of Samchuk and Donghae in 2000. Fire scars were formed on the bark of trees when fire passed by the tree. Fire scarring is usually found on the windward and leeward sides of the tree. Fire spread was analyzed topographically using the fire scars formed at the tree stem. Fire spread was closely related to the shape, slope and direction of the forestland. Four fire direction types are classified according to the shapes of the forestland. The height of the fire scar was higher on the leeward side than on the windward side of the trees studied. The burnt area of the total bark of the tree was over 30% in dead trees and below 12% in living trees. The regression model of the burnt stem area using the height of the fire scar, the diameter of breast height and the height of tree was Y=-2.484${\times}$Height＋0.04199${\times}$D.B.H-1.686${\times}$Windward＋11.172${\times}$Leeward＋23.432(r=0.936, F=409.968, P＞0.0001).

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.119-131
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• 2003

Rainfall-runoff process is under the control of hydrologic parameters having temporal and spatial variety. Accordingly, it is difficult to efficiently deal them since many parameters and various information are required to perform hydrologic simulation. So the purposes of this study is to estimate the runoff volume by frequency using GIS techniques and NRCS method. The analysis of frequency rainfall is analyzed using FARD 2002 program and the result of goodness of fit test show that Log-pearson type III is suitable distribute type for the applied area. TOPAZ program used for the analysis of DEM data examining into geological characteristic. NRCS curve numbers estimated using landuse map and soil map for the estimation of effective rain fall in the basin. The storm Type II and Type III were used as the type for the application of NRCS. The result of application show that the runoff volumes above 80 years frequency in return period have similar patterns regardless of Type II and Type III. In addition, the results of comparison with runoff volumes by frequency in the report of river improvement master plan show that it have similar volumes as the relative errors for them of 80, 100 years frequency are each 7.65%, 5.33%.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.32-46
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• 2017

Recent rapid urban expansion and crowding of various industrial facilities has affected the features of a significant part of downtown area, resulting in areas having buildings with a wide range of height and the foothills. To compute a velocity pressure exposure coefficient, namely the design wind speed factor, this study defines ground surface roughness by utilizing concentration analysis for the height of each building. After obtaining spatial data by extracting a building layer from digital maps, the study area was partitioned for the concentration analysis and to allow investigation of the frequency distribution of building heights. Concentration analysis by building height was determined with the Variation-to-Means Ratio (VMR) and Poisson distribution analysis using a buildings distribution chart, with statistical significance determined using Chi-square verification. Applying geographic information systems (GIS) with the architectural information made it possible to estimate a velocity pressure exposure coefficient factor more quantitatively and objectively, by including geographic features, as compared to current methods. Thus, this method is expected to eliminate inaccuracies that arise when building designers calculate the velocity pressure exposure coefficient in subjective way, and to help increase the wind resistance of buildings in a more logical and cost-effective way.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.5
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• pp.40-47
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• 2003

This study examined the improved effect of wear tolerance of warm-season turfgrass overseeded with cool-season turfgrasses. Also, it investigated the improved effect of crumb rubber on wear tolerance and the difference anmong cultivars regarding the wear of Zoysia spp. In wear experiment during summer, the warm-season turfgrass overseed with cool-season turfgrasses had a higher visual rating on the ground than the monostand of Cynodon dactylon. Moreover, in wear experiment in winter, barrenness showed significant progress in the monostand of C. dactylon, while the barrenness did not appear at all in overseeded turf with cool-season turfgrasses. As a result of investigating the bulk density was increased in the monostand of C. dactylon, but not in the overseed turf with cool-season turfgrasses. From the above result, the wear tolerance effcect of turfgrasses appeared year round through warm-season and cool-season turfgrass mixtures. Also, it was found that the method of topdressing crumb rubber on the ground was effective as a physical assistant device alleviating damage of turfgrasses. The possibility of improving wear tolerance was accepted by adding soil amendments such as perlite, pamis, etc., in order to promote the growth of turfgrass.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.12-17
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• 1989

Soil and water temperature were evaluated to relate rice growth to topographical chracteristics in paddy soils. Water temperature (WT) and so il temperature (ST) were measured under the various altitudes, slopes and irrigation methods. Temperature fluctuation and growth status in the same field were measured; 1. Air temperature (AT) and ST of 10cm soil depth were decreased with increasing altitude. Difference of its fluctuation in AT, WT and ST of 10cm soil depth in the lapse rate was 0.64, 0.84 and $0.82^{\circ}C$ per 100m elevation, respectively. 2. Maximum WT, in panicle initiation stage, was decreased slowly with increasing altitude whereas minimum WT fallen rapidly. It suggested that the lapse rate of WT was affected by minimum WT. 3. Source of irrigation water and irrigation method affected the WT. WT, ST and rice growth varied with the locations within the same field. 4. Pumping irrigation of artesian well resulted in more fluctuation of WT between irrigation intervals than did the conventional irrigation.