• Proceedings of the Speleological Society Conference
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• 1996.09a
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• pp.67-74
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• 1996

동굴이 오랫동안의 세월을 걸치면서 그 지역의 지질 구조나 지형, 그리고 지표면의 기상 조건과 식생 환경들에 의하여 동굴 나름대로의 특성을 지니고 있음은 우리가 잘 알고 있는 바이다. 이번 발표에서는 일반적으로 여태까지 개발 이용되어 온 동굴의 환경 변화를 언급하면서 이와 같은 공개된 동굴들이 외국에서는 어떻게 이용되어 왔는가, 그리고 이 동굴들은 어떻게 환경보전 대책을 세우고 있는가 등에 대한 몇 개소의 사례를 들어 설명하고자 한다.(중략)

• Journal of Korean Society of Forest Science
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• v.86 no.2
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• pp.241-250
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• 1997

The study was conducted to make a map for selecting righteous tree species for each site by digital terrain analysis. We set an algorithmic value for each tree species' characteristics with distribution pattern analysis, and the soil types were digitized from data indicated on soil map. Mean altitude, slope, aspect and micro-topography were estimated from the digital map for each block which had been calculated by regression equations with altitude. The results obtained from the study could be summarized as follows 1. We could develope a method to select righteous tree species for a given site with concern of soil, forest condition and topographic factors on Muju-Gun in Chonbuk province(2,500ha) by the terrain analysis and multi-variate digital map with a personal computer. 2. The brown forest soils were major soil types for the study area, and 29 tree species were occurred with Pinus densiflora as a dominant species. The differences in site condition and soil properties resulted in site quality differences for each tree species. 3. We tried to figure out the accuracy of a basic program(DTM.BAS) enterprised for this study with comparing the mean altitude and aspect calculated from the topographic terrain analysis map and those from surveyed data. The differences between the values were less than 5% which could be accepted as a statistically allowable value for altitude, as well as the values for aspect showed no differences between both the mean altitude and aspect. The result may indicate that the program can be used further in efficiency. 4. From the righteous-site selection map, the 2nd group(R, $B_1$) took the largest area with 46% followed by non-forest area (L) with 23%, the 5th group with 7% and the 4th group with 5%, respectively. The other groups occupied less than 6%. 5. We suggested four types of management tools by silvicultural tree species with considering soil type and topographic conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.375-382
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• 1986

This study was carried out to obtain the basic information for the clarification of spring growth habits mechanism of naked barleys. The isozyme patterns and activities of peroxidase in the young spike and leaf blade were analyzed during the differentiation and development of young spike. The characteristic differences between the normal and rosetted type were in c and g isozymes in young spike, and in i isozyme in the leaf blade. In the normal type, c and i isozymes disappeared at the stage of spi-kelet differentiation, g isozyme at the stage of flolet differentiation. But, in the rosetted type, those three isozymes remained in dark stained condition until the time of final sampling. Especially, those three isozymes were higher in the rosetted type than those in the normal type even at the stage of bract differentiation(BDS), just prior to the reproductive stage. The activities of peroxidase decreased slowly after BDS in the young spike and leaf blade in the normal type, While, in the rosetted type, increased linearly, and the degree of increasing was remarkable in the young spike. It was interesting that the degree of activities in young spike was higher in the rosetted type than that in the normal type even at BDS. From the above results, the remarkable differences of the isozyme patterns and activities at BDS between the normal and rosetted type were considered to be the physiological expression of the varieties concerned with the degree of spring growth habits.

• The Journal of Engineering Geology
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• v.15 no.2 s.42
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• pp.105-121
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• 2005

Most of the landslides triggered by intensive rainfall on natural slope occur serious damages of human beings and properties. There have been many landslides since 1991 in Gyeonggi province. The influential factors are rainfall, topography, geology and soil properties. There were 660 landslides occurred by intensive rainfall as much as 250mm at Yongin and Anseong area from Tuly 19th to luly 21st,1991 This study surveyed location, topography, geology, geometry of the landslide and rainfall at the area and analyzed occurrence characteristics of the landslides. Most of the landslides occurred on the soil layer above the bed rock. They showed changes of landslide types from translational slides at the head part to flow at the central part. The landslides have relatively small magnitude of which length is shorter than 50m. In order to identify characteristics of landslides dependent on soil conditions, geotechnical properties of soil were evaluated by laboratory tests using soil samples which were collected on slided area and not-slided area. Soil properties of the slided area show high percentage of coarse material such as gravel and sand. However, soil of the not-slided area is mainly composed of fine material such as silt and clay. Permeability coefficients of the slided area are higher than those of the not-slided area.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.195-206
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• 1993

The purpose of this study is to provide a basis for establishing regional harvesting systems that ist the prerequisites for the forest mechanization. The factors restricting to the forest harvesting and logging methods from topographical aspects are studied for this purpose. Three main harvesting methods studied in this paper are : shortwood method, longwood method and full tree method. This study shows : the shortwood method is suitable for low, the longwood method for medium, the full tree method for high topographical conditions. For the logging methods, the focus of the study is on various ground based logging systems by animalpower, manpower, gravitation, wheeled & crawler vehicle and cable. The factors limiting the coverage of logging operation are slope and logging distance. The cable crane logging methods are classified by logging distance into short distance(to 300 or 400m), middle distance(to 700 or 800m) and long distance cable crane methods (over 700 or 800m). The wheeled vehicle method shows serious damages to forest resources, whereas the logging by log-line of the gravitation logging method and cable crane method tend to minimize such damages. The wheeled & crawler vehicle method also shows difficult to apply in the high slope conditions, whereas cable crane method can be applied to maximum 120% steep slope and uphill conditions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.308-320
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• 2021

An integrated sediment management approach that includes the recovery of the amount of declined sediment supply is effective as a fundamental solution to coastal erosion. During planning, it is essential to analyze the transfer mechanism of the sediments generated from estuaries (the junction between a river and sea) to assess the amount and rate of sediment discharge (from the river to sea) supplied back to the coast. Although numerical models that interpret the tidal sand bar flushing process during flooding have been studied, thus far, there has been no study focusing on the formation and development processes of tidal sand bars. Therefore, this study aims to construct wave deformation, flow regime calculation, and topographic change analysis models to assess the amount of recovered sediment discharge and reproduce the tidal sand bar formation process through numerical analysis for integrated littoral drift management. The tidal sand bar formation process was simulated, and the wave energy and duration of action concepts were implemented to predict the long-term littoral movement. The river flux and wave conditions during winter when tidal sand bars dominantly develop were considered as the external force conditions required for calculation. The initial condition of the topographic data directly after the Maeupcheon tidal sand bar flushing during flooding was set as the initial topography. Consequently, the tidal sand bar formation and development due to nearshore currents dependent on the incident wave direction were reproduced. Approximately 66 h after the initial topography, a sand bar formation was observed at the Maengbang estuary.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.166-174
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• 1995

This experiment was conducted to investigate a cause of summer depression of cool season turfgrass, using nine cultivars in warm season and twenty-eight cool season turfgrasses. Even though an average of apparent photosynthesis(APS) per fresh weight was 13.09 mg $CO_2$/g/h in warm season turfgrass and 7.75 mg $CO_2$/g/h in cool season turfgrass, the Creeping bentgrass in cool season type was higher than Kikuyugrass and Bahiagrass in warm season type. The optimum temperature for the heighest APS was $30^{\circ}C$ in warm season type and $25^{\circ}C$ in cool season type. In $CO_2$ compensation point(CCP) as an index of dark respiration, it was higher in cool season turfgrass(75.6ppm) than warm season turfgrass(29.5ppm). In warm season type, even though the temperature increased from $25^{\circ}C$ to $40^{\circ}C$ the CCP was not increased. But the higher temperature rises the more increased CCP in cool season type. Dark respiration(DR) was higher in cool season type than warm season type under various temperature conditions, but the increasing ratio of DR with the temperature increment was not so much differed between two types.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.4
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• pp.238-245
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• 2015

Recently, Choi et al.(2015) showed that a numerical simulation of the SandyDuck experiment under a directional random wave environment agreed well with the experimental data including the wave height distribution of the random waves, the well-developed longshore current and its energetic fluctuation. Based on the Boussinesq modeling, this study investigates the effect of the alongshore variations, which are induced by not only the field topography but also the phase interaction of multidirectional random waves in the surf zone wave field, on the rip currents. As a result, transient rip currents as well as topographical rip currents cause the complicated surfzone circulation and mixing process due to their interactions in a multi-directional random wave condition while the topographical rip currents are dominant in a monochromatic wave condition.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.3
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• pp.79-89
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• 2004

Remote sensing technique is a probable means to estimate distribution of actual evapotranspiration in connection with regional characteristics of vegetation and landuse. The factors controlling evapotranspiration from ground surface are air temperature, humidity, wind, radiation, soil moisture and so on. Not only the vegetation influences directly the evapotranspiration, but also these factors strongly influences the vegetation growth at the area. Therefore, it can be expected that evapotranspiration is highly correlated to vegetation condition. The normalized difference vegetation index (NDVI) showed excellent ability to get the vegetation information. The NDVI is obtained using NOAA/AVHRR have been studied as a tool for vegetation monitoring. In this paper, a simple method to estimate actual avapotranspiration is proposed based on vegetation and meteorological data.

• Journal of Wetlands Research
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• v.7 no.4
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• pp.43-50
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• 2005

Wetlands can transform or remove pollutants from water body, such as nitrogen, phosphate, and organics. Many researches were conducted in relation to uptake process by aquatic plants in wetlands. However, water purification processes in wetlands are the results of physical, chemical and biological, especially microbiological reactions. As such, understanding on microbial processes is of great importance. In this study, we used pondor marsh-type wetland microcosms for investigating the water purification capacity and microbial functions, namely, extracellular enzyme activities, nitrification and denitrification. In a pond system, removal efficiencies of $NO_3{^-}$ and $PO{_4}^{3-}$ were 96% and 100 % respectively, while those in a marsh system were 94%, 100% respectively. These high removal efficiencies appeared to be caused by high adsorption ability to soils and microbial functions in wetland.