• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.10
• /
• pp.901-906
• /
• 2010

A three-dimensional flow simulation was performed to investigate the flow field in a wind farm on a complex terrain. The present study aims to examine the effects of mountainous terrain and turbine arrangement on the performance of wind power generation. A total of 49 wind turbines was modeled in the computational domain; detailed blade shape of the turbines was considered. Frozen rotor method was used to simulate the rotating operation. The torque acting on the turbine blades was calculated to evaluate the performance of the wind turbines. The numerical results showed details of the flow structure in the wind farm including the velocity deficit in the separated flow regions; this velocity deficit was due to the topographical effect. The effect of the wake induced by the upstream turbine on the performance of the downstream wind turbine could also be observed from the results. The methodology of the present study can be used for selecting future wind-farm sites and wind-turbine locations in a selected site to ensure maximum power generation.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.2 no.4
• /
• pp.175-182
• /
• 2000

Spatial interpolation of daily temperature forecasts and observations issued by public weather services is frequently required to make them applicable to agricultural activities and modeling tasks. In contrast to the long term averages like monthly normals, terrain effects are not considered in most spatial interpolations for short term temperatures. This may cause erroneous results in mountainous regions where the observation network hardly covers full features of the complicated terrain. We developed a spatial interpolation model for daily minimum temperature which combines inverse distance squared weighting and elevation difference correction. This model uses a time dependent function for 'mountain slope lapse rate', which can be derived from regression analyses of the station observations with respect to the geographical and topographical features of the surroundings including the station elevation. We applied this model to interpolation of daily minimum temperature over the mountainous Korean Peninsula using 63 standard weather station data. For the first step, a primitive temperature surface was interpolated by inverse distance squared weighting of the 63 point data. Next, a virtual elevation surface was reconstructed by spatially interpolating the 63 station elevation data and subtracted from the elevation surface of a digital elevation model with 1 km grid spacing to obtain the elevation difference at each grid cell. Final estimates of daily minimum temperature at all the grid cells were obtained by applying the calculated daily lapse rate to the elevation difference and adjusting the inverse distance weighted estimates. Independent, measured data sets from 267 automated weather station locations were used to calculate the estimation errors on 12 dates, randomly selected one for each month in 1999. Analysis of 3 terms of estimation errors (mean error, mean absolute error, and root mean squared error) indicates a substantial improvement over the inverse distance squared weighting.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.151-156
• /
• 2011

Previously most of flood prevention efforts have been made for relatively large watersheds near to channel flow. However, as economical development and the expansion of leisure areas to mountainous region, human casualty by flash flood occurs frequently, requiring additional prevention activity. Therefore, to reduce the damage of human lives and property by flash flood, we develop an assessment method for flash flood occurrence for mountainous areas considering various factors involving it. PROMETHEE(Preference Ranking Organization METHod for Enrichment Evaluations) which is one of the MCDM(Multi-Criteria Decision Making) was adopted to assess the contribution of each factor to the risk of the flash flood in the mountainous area. The main evaluation criteria are classified into three categories, namely, the regional and rainfall characteristics, and geographical features. Also, the Entropy method is used to determine the weight of each evaluation criteria without survey. The suggested method based on PROMETHEE with Entropy method is applied to BongHwa region to verify its applicability. After applied, the method successfully assesses the relative risk of flash flood occurrence of each sub region in the BongHwa region. Out of the seventeen sub-regions, five, seven and five of them are evaluated as high-risk, medium-risk, and low-risk, respectively. To verify the results, we searched the historical data of flash flood and the flash flood had occurred in one of high-risk sub-regions at 2008.

• Journal of the Korean association of regional geographers
• /
• v.4 no.2
• /
• pp.15-30
• /
• 1998

Physical geography is the discipline which deals with the relationship between man and natural environment. Therefore, it should be studied as the organized unity. In this paper I recognize the drainage basin as a framework outlining physical geography, describe the difference of inhabitant's life style due to the difference of natural environment in the drainage basin, and consider the meaning of drainage basin as a unit of life(and unit of regional geography). Munkyung is divided into three regions(intermontane basin region, middle mountainous region, marginal hilly region of the great basin) owing to the topographic characteristics. Subdivision in these regions is related closely to drainage network distribution, specially in intermontane basin region. And small regions have developed with the confluence point of $3{\sim}4$ order streams as the central figure. Intermontane basin region is the valley floor of Sinbuk-Soya-Kauun-Nongam stream located in the limestone region which is exposed according to Munkyung fault at its northern part. Small streams are affected strongly by the influence of the NNE-SSE or WNW-ESE tectolineament. Thus Kaeripryungro(鷄立嶺路), Saejaegil(새재길), Ewharyungro(伊火嶺路) and so on are constructed through the tectolineament. In the valley floors of small streams which flow into the intermontane basin, there are large floodplains. Floodplain in Sinbuk, Joryung, and Yangsan stream is used to paddy field or orchard, and in Nongam stream is used to paddy field or vegetable field. Hills are distributed largely in the periphery of intermontane basin. Limestone hills in Kauun and Masung basin are not continuous to the present low and flat floodplain, and most of those are used to forest land and field. On the other side. granite hills in Koyori are continuous to be used to the present floodplain, and they are used to residential area and field. In the middle mountainous region are there hilly mountains constructed in the geology of Palaeozoic Pyeongan System in northern area and Chosun System's Limestone Series in southern area, and banded gneiss and schist among Sobaeksan Gneiss Complex. In Palaeozoic Pyeongan System region are there relatively rugged mountains and ingrown meanders developed along tectolineaments. Chosun System's Limestone Series region builds up a geomorphic surface, develops various karst landforms. Mountainous area is used to field. On the other hand, especially in case of Hogye, valley bottom is wide, long, and discontinuous to slope, is used to paddy field dominantly. And schist region in Youngnam Block of Pre-Cambrian is rugged mountainous. Marginal hilly region of the great basin is hilly zone located in the margin of erosional basin(Bonghwa-Youngju-Yechon-Hamchang-Sangju). This region is lower geomorphic surface which is consisted of hills of $50{\sim}100$m height. Hills are used to field or orchard, and dissected gentle depression is used to paddy field.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.3
• /
• pp.229-235
• /
• 1985

Zoning of the agroclimatic regions was attempted based on the distribution of drought index, effective temperature, meteorological factors and their standard deviation and a climatic productivity derived from yield response of rice to temperature and sunshine hours. The meteorological data obtained from synoptic weather stations under the Central Meteorology Office and simple weather observatories under the Rural Development Administration at 155 locations throughout the country were computerized in the PDP11/70, RDA Computer Center, to analyze the climatic similarities among the locations, except the Jeju Island. The nineteen different agroclimatic regions were classified, ego the Taebaeg Mountainous Region. the Charyung Southern Plain Region, etc., and the climatic characteristics of the regions were identified.

• Biomedical Science Letters
• /
• v.23 no.3
• /
• pp.277-280
• /
• 2017

Elsholtzia splendens, which grows on moist soil of mountainous regions, is widely distributed at all regions of Korea, especially at Mountain Ji ri. It is categorized as a Labiatae plant which is dried aerial part. It has the following medicinal properties; removal of fever, alleviation of pain, a good antiphlogistic agent as well as antibacterial effects. However, the effects of E. splendens on thrombosis and platelet activation are not precisely understood. We performed this study to develop antithrombotic agents from oriental medicine herb extracts. E. splendens inhibited platelet aggregation induced by arachidonic acid and U46619 in a concentration dependent manner. E. splendens did not show an effect on anticoagulation as determined by prothrombin time (PT) or activated partial thromboplastin time (aPTT). We also tested the effects of E. splendens using a carotid artery thrombosis rat model induced by 35% $FeCl_3$ treatment. E. splendens significantly inhibited thrombus weight compared with the control group. These results show that E. splendens may be developed as a potential antiplatelet activity agent for treatment of cardiocerebrovascular disease and atherosclerosis.

• The Plant Pathology Journal
• /
• v.20 no.2
• /
• pp.92-96
• /
• 2004

Environmental factors such as soil moisture, land management, and weather conditions affecting Fusarium wilt of sweet potato were investigated in major sweet potato cultivation regions in Korea. Fusarium wilt occurred mainly in reclaimed terracing lands, which are flattened and located in hilly to mountainous areas at the base of the mountain, in early seasonal cultivation regions. Disease severity was lower in reclaimed fields with natural slope. The development of Fusarium wilt in the fields was highly correlated with precipitation during planting period (r=-0.96**). Fusarium wilt was more severe in fields with less than 20 cm of available soil depth than in fields with over 20 cm of available soil depth. Greenhouse studies were consistent with field studies that less soil moisture content caused severe Fusarium wilt of sweet potato. These results indicate that low rainfall and moisture of soil with low effective soil depth during planting period are important environmental factors influencing the development of Fusarium wilt.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.782-789
• /
• 2010

Landslides cause enormous economic losses and casualties. Korea has mountainous regions and heavy slopes in most parts of the land and has consistently built new roads and large-scale housing complexes according to its industrial and urban growth. As a result, the damage from landslides becomes greater every year. In this study, performed a GIS-based landslide hazard analysis by SINMAP(Stability Index MAPping) model in Gyeonggi Icheon area coupling with geomorphological and geological data. SINMAP model has its theoretical basis in the infinite plane slope stability model with wetness obtained from a topographically based steady state model of hydrology. To Gyeonggi Icheon area landslides hazards evaluated, these SINMAP model were analysed results while simultaneously referring to the stability index map, where lines distinguish the zones categorized into the different stability classes and a table giving summary statistics.

• Journal of Korean Society of Rural Planning
• /
• v.1 no.2
• /
• pp.103-121
• /
• 1995

This study was carried out to identify the problems and policy alternatives for the improvement of living conditions and environmentally friendly agriculture. The results of surveys on the current situations of living conditions in the rural areas revealed that the main cause of depopulation in Korean rural villages was the lack of social infrastructure and income sources. The current government policies for agriculture geared mainly for improvement of international comparative competitiveness will result in the further disadvantage against the mountainous regions with marginal agricultural lands. Therefore, it is recommended that the agricultural policy should be complemented by the environmental and social policies in the less favoured areas. This can be justified by the fact that the demand for environmental public goods such as recreational opportunities in rural settings uncontaminated by the industrial wastes is growing.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.178-182
• /
• 2007

In this study, we evaluated current raingauge network of Soyanggang dam region applying spatial-correlation analysis and Entropy theory to recommend an optimized raingauge network. In the process of analysis, correlation distance of raingauge stations is estimated and evaluated via spatial-correlation method and entropy method. From this correlation distances, respective influencing radii of each dataset and each methods is assessed. The result of correlation and entropy analysis has estimated correlation distance of 25.546km and influence radius of 7.206km, deducing a decrease of network density from $224.53km^2$ to $122.47km^2$ which satisfy the recommended minimum densities of $250km^2$ in mountainous regions(WMO, 1994) and an increase of basin coverage from 59.3% to 86.8%. As for the elevation analysis the relative evaluation ratio increased from 0.59(current) to 0.92(optimized) resulting an obvious improvement.