• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.222-234
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• 2021

Airborne-pests can be introduced into Korea from overseas areas by wind, which can cause considerable damage to major crops. Meteorological models have been used to estimate the wind trajectories of airborne insects. The objective of this study is to analyze the effect of input settings on the prediction of areas where airborne pests arrive by wind. The wind trajectories were predicted using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The HYSPLIT model was used to track the wind dispersal path of particles under the assumption that brown plant hopper (Nilaparvata lugens) was introduced into Korea from sites where the pest was reported in China. Meteorological input data including instantaneous and average wind speed were generated using meso-scale numerical weather model outputs for the domain where China, Korea, and Japan were included. In addition, the calculation time intervals were set to 1, 30, and 60 minutes for the wind trajectory calculation during early June in 2019 and 2020. It was found that the use of instantaneous and average wind speed data resulted in a considerably large difference between the arrival areas of airborne pests. In contrast, the spatial distribution of arrival areas had a relatively high degree of similarity when the time intervals were set to be 1 minute. Furthermore, these dispersal patterns predicted using the instantaneous wind speed were similar to the regions where the given pest was observed in Korea. These results suggest that the impact assessment of input settings on wind trajectory prediction would be needed to improve the reliability of an approach to predict regions where airborne-pest could be introduced.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.1
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• pp.1-11
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• 1994

A curvilinear hydrodynamic three-dimensional model is presented for the study of wind-driven circulation in a shallow lake. Numerical results are compared with field data. Thermal stratification effects were found to be critical to the successful simulation of circulation under increasing winds. When there ate insufficient meteorological data, the so-called inverse method can be used for the estimation of heat flux.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.301-302
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• 2003

최근 수년간 동아시아지역의 황사는 국가간의 오염확산이라는 측면에서 매우 중요하게 취급되어지고 있다. 대부분의 황사연구는 침적량 예측을 주로 다루고 있는데, 한반도의 경우 매우 복잡한 지형분포를 하고 있어서 침적량의 분포를 정확히 추정하는데 어려움이 있다. 이러한 침적량의 예측연구에 기초적으로 사용되는 자료가 3차원의 바람장 예측자료이다. 지금까지의 황사 및 오염물 대기확산연구에 사용되는 바람자료는 한 지점의 관측치를 그 지역의 대표치로 간주하여 사용을 하거나, 지구규모의 바람장을 내ㆍ외삽을 하여 사용한 것이다.(Kim and Shin, 1991). (중략)

• Environmental and Resource Economics Review
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• v.7 no.1
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• pp.151-164
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• 1997

물부족현상을 해결하기 위해서는 장기적인 공급기반시설의 확충과 함께 여러 형태의 경제적 유인제도의 활용을 통한 수요관리정책을 병행함으로써 물의 절약효과를 최대화시키는 것이 바람직하다. 본 연구에서는 1993년 한국 제조업을 대상으로 시장구조적, 환경적 제약여건하에서 공업용수의 비효율적인 사용실태를 알아보고 적정수준의 용수수요량을 유도하기 위하여 용수가격의 인상을 추진할 경우, 이에 필요한 가격인상율을 제시한다. 방법론적으로는 적정수준의 자본투입을 가정한 제약일반비용함수를 추정한다. 추정결과, 공업용수는 적정수준에 비해 무려 평균 50배 이상 과다하게 사용되고 있으며 1993년 현재의 용수가격을 106.8% 인상시켜야 적정수준으로 유도할 수 있는 것으로 나타났다.

• Journal of Biosystems Engineering
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• v.4 no.2
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• pp.25-31
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• 1979

본연구는 건조에 필요한 열과 공기를 열원으로부터의 자연대류만에 의존하는 간역화력건조기의 성능향상을 도모하기 위하여 실시되었으며 옥수수를 대상으로 모형실험을 통하여 분석한 결과는 다음과 같이 요약된다. 1. 건조기 화구의 공기열입구의 크기는 송풍량에 영향을 미치며 공기의 유입속도가 16m/min 이하가 되도록 충분히 만들어야 한다. 2. 곡물층을 통과하는 송풍량은 곡물층의 두께가 클수록 증가하며 송풍량과 곡물층 두께와의 관계는다음식으로 나타났다. $q=CD^{-k}$ 3. 송풍량은 실험범위내에서는 열원으로부터 곡물층의 높이와 가열공기의 온도상승에 따라 각각 직선적으로 증가하였다. 4. 송풍량은 곡물층의 두께, 열원으로부터의 곡물의 높이 및 가열공기의 온도상승에 의하여 옥수수층의 경우 다음과 같이 추정될 수 있다. $ q=0.00265H(\Delta T) D^{-0.76}$ 5. 바람이 송풍량에 미치는 영향은 매우 커서 8km/hr의 풍속을 가진 바람이 유입구측으로부터 볼 때 송풍량은 바람이 없을 때보다 무려 5배나 증가하였다. 6. 건조실의 전후방간의 가열공기의 온도차이는 열원으로부터 곡물층의 높이가 낮을수록 증가하였으며 이 현상은 바람이 불 때 더욱 현저하게 나타났다. 7. 건조기의 벽면을 통한 열손실은 열원으로부터 곡물층의 높이와 가열공기의 온도상승에 따라 각각 직선적으로 증가하였다.

• Korean Journal of Remote Sensing
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• v.14 no.1
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• pp.37-52
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• 1998

The NSCAT(NASA Scatterometer) carried by the japanese Advanced Earth Observing Satellite(ADEOS) was the first high resolution(25 km) device for the direct wind measurement over the ocean. Even it was ceased to operate in lune of 1977 because of the power failure, it gave the first opportunity to the marine meteorologists to study the direct measured ocean wind during its 9 months of operation, especially around Korea. This study is to show monthly mean ocean wind and wind stress curl fields around Korea from January, 1997 to June, 1997. Mean ocean winds in January are predominantly northwesterly and the strongest wind(12 m/s) is found near Vladivostok. The winds in the western East Sea are strongly inf1uenced by the mountain range in Korea and these topographically influenced winds make about five times larger wind stress curl fields than previous estimates based on the weather maps. The calculation of Sverdrup transport in the East Sea shows the possibility of the directional change of the East Korean Cold Current from southward to northward direction caused by the winter wind. The downwelling area near North Korea has maximum estimated speed of 45 m in january and this wind induced downwelling makes good condition for the formation of Intermediate East Sea Water together with vigorous mixing by the strong wind.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.309-316
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• 2017

In baseball, estimation of winning percentage is critical and many studies for this topic have been actively performed. Pairwise winning percentage estimation using Pythagorean winning percentages of individual teams against other individual teams has the property that the sum of estimated winning percentage totals must be a constant. In this paper, we consider two types of pairwise estimation including linear formula and Pythagorean formula to the Korean baseball data of seasons from 2013 to 2016 under the criterions of RMSE and MAD. In conclusion, pairwise Pythagorean methods have the smaller RMSE and MAD than traditional Pythagorean methods. We suggest the optimal pairwise Pythagorean formula with a fixed exponent. Also we show that there are very little differences of RMSE and MAD between variation in exponent values.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.2
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• pp.35-42
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• 2001

We demonstrated the importance of initial estimates of model parameters and the utility of an optimization approach of the uncertain forcing of wind-driven circulation off the southeastern coastal waters of Korea. The wind stress represents the upper boundary condition in this model and enters in the model equation as a forcing term in the numerical formalism. The wind field contributes to maintain the almost time-independent distribution of the upper layer thickness feature in a north-south direction and negative wind stress curl to maintain the formation of warm eddy off the southeastern coastal waters of Korea. Elucidated is the variational characteristics of the East Korean Warm Current due to the variations of the zonally averaged wind stress (southward transport) from the seasonal variations of the meridional transport by the Ekman transport.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.378-386
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• 2019

Unlike ship noise that radiates from moving ships, wind noise is caused by breaking waves as a result of the interaction between the wind and the sea surface. In this paper, WNL (Wind Noise Level) was modeled by considering the noise source of the wind as the bubble cloud generated by the breaking waves. In the modeling, SL( Source Level) of the wind noise was calculated using the wind-speed data measured from the weather buoy operated in the coastal area of the East Sea. At the same time as observing the wind speed, NL (Noise Level) was continuously measured using a self-recording hydrophone deployed near the weather buoy. The modeled WNL according to the wind speed and the measured NL removing the shipping noise from the acoustic raw data were compared in the low-frequency band. The overall trends between the modeled WNL and the measured NL were similar to each other. Therefore, it was confirmed that it is possible to model the WNL in the shallow water considering the SL and distribution depth of bubble cloud caused by the wind.

• Communications for Statistical Applications and Methods
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• v.3 no.3
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• pp.135-144
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• 1996

표본조사에서는 실사의 비용의 줄어주고 추정치의 정도를 높여 주는 바람직한 표본이 추출되기를 기대한다. Goodman과, Kish(1950)는 기존의 추출방법의 성질을 변화하지 않으면서 바람직한 표본의 추출확률의 놓게 해주고 반면에 바람직하지 않은 표본의 추출확률을 작게 해주는 관리적 선정(controlled selection) 방법을 제시하였다. 본 논문에서는 지금까지 관리적 선정방법이 갖고 있는 한계점과 실제조사에 이 방법을 적용할 때 발생하는 문제점을 파악하여, 향후 관리적 선정방법을 효율적으로 사용하기 위한 연구 방향과 관제를 제시하였다.