• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.579-582
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• 2008

Three dimensional(3D) Poisson's equation is used to calculate the potential variation in the channel to analyze subthreshold current and short channel effect(SCE). The analytical model has been presented to lessen calculating time and understand the relationship of parameters. The accuracy of this model has been verified by the data from 3D numerical device simulator and variation for dimension and process parameters has been explained. The model has been developed to obtain channel potential of FinFET according to channel doping and to calculate subthreshold current and threshold voltage.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.12
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• pp.839-846
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• 1988

If we use the 2-dimensional analyzing method with the magnetic vector potential for the analysis of eddy current distribution in electric machinery, we can obtain the magnitude of eddy current but can't have the characteristic of eddy current distribution. For the settlement of this problem, we have induced the governing equation with the current vector potential and attemptted 2-dimensional analysis of eddy current distribution by finite element method. And the time domain weighted residual method is used in treatment of time differential term and we have developed the algorithm by it. And then, we analyze eddy current distributions of analytic model and aluminium disk in singlephase watt hour meter. Consequently we have verified the propriety and utility of above mentioned method.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.2
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• pp.32-42
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• 1995

When the thickness becomes so small as in the case of the trailing edge of the propeller blade or when the curvature of the surface varies rapidly as in ship stem, the existing panel method employing a flat-surface panel, obtained by collapsing the original non-planar surface into its mean location, suffers the leakage problem and also gives inaccurate induction upon the field point very close to the panel. The hyperboloidal panel deals with the induction from the dipole distributed on the non-planar surface without approximation, overcoming the defects of the flat-surface panel. This paper introduces two distinct derivations of the formulae to compute the integral for the potential induced by a dipole of uniform density distributed on a non-planar hyperboloidal surface element. One method is based on the Gauss-Bonnet theorem and the other is based on the transformation of the surface integral into a line integral.

• The Korean Journal of Applied Statistics
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• v.5 no.2
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• pp.113-121
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• 1992

Statistical interpolation which uses past experience about the behaviour of the atmosphere(correlation function) to interpolate the observations irregularly distributed in space and time to regular grids is discussed. Correlation functions are computed in the Far East Asian region during the winter periods of December 1977 to February 1980. Results show from the computation of correlation functions that there exists a large difference in the autocorrelation functions by slowly decreasing geopotential height and temperature, and rapidly decreasing wind and mixing ratio with increasing data-correlation functions between geopotential height and wind are well corresponed to persistence of wintertime synoptic features.

• Communications of the Korean Mathematical Society
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• v.15 no.3
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• pp.391-434
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• 2000

심플렉틱 구조는 국소적으로는 모두 같기 때문에 심플렉틱 다양체 연구는 대역적으로 연구해야한다. 그로모브가 복소해석학적 곡선을 원소를 하는 모률라이 공간의 연구가 심플렉틱 다양체를 연구하는 물고를 텃다. 특이점이 없는 복소곡선의 개수를 세는 그로모브 불변량은 도넬슨의 비선형 게이지 이론의 간략화라 할 수 있는 아벨리안게이지 이론에서 사이버그-위튼 불변량과 같음을 타우브스가 발견하였다. 또한 사이버그-위튼 불변량은 심플렉틱 다양체의 불변량으로 심플렉틱 구조연구에 큰 이바지하고 있다. 그로모브의 모듈라이 공간의 컴펙트하는 과정에서 자연스럽게 마크점과 특이점을 갖는 곡선의 그로모브-위튼 모듈라이 공간이 켐펙트가 되고 여기소 그로모브-위튼 불변량이 얻어진다. 이 그로모브-위튼 불변량은 대수기하와 이론 물리학의 끈이론에서 찾는 대수곡선의 개수를 나타내고, 코호몰로지의 컵곱의 일반화라 할 수 있는 퀸텀곱을 유도하고, 그로모브-위튼 포텐셜함수의 계수를 결정한다. 퀸텀곱의 결합법칙은 포텐셜함수의 WDVV-방정식과 동치를 나타나며 이는 프로베니우스 구조가 평탄함을 나타낸다. 그로모브-위튼 불변량은 앞으로 활발히 연구되고 수학에 광범하게 이바지 할 것이다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.3
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• pp.58-71
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• 2022

Analytical solutions for two-dimensional velocities of regular waves generated by bottom wave makers in a flume were derived in this study. Triangular and rectangular bottom wave makers were adopted. The velocity potential was derived based on the linear wave theory with the bottom moving boundary condition, kinematic and dynamic free surface boundary conditions. Then, analytical solutions of two-dimensional particle velocities were derived from the velocity potential. The velocity potential and two-dimensional particle velocities which were derived as complex integral equations were numerically calculated. The solutions showed physically valid results as velocities of regular waves generated by bottom wave makers in a flume.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.1
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• pp.73-86
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• 1993

This paper describes a potential-based panel method for the prediction of steday performance of a marine propeller operating in a uniform oncoming flow. An integral equation with unknown dipole strengths is formulated by distributing the normal dipoles and/or sources on the blade and hub surfaces and the wake sheet, and is solved numerically upon discretization. A hyperboloidal panel has been adopted to compute the potential induced by a normal dipole on a non-planar quadrilateral panel. The Kutta condition is satisfied by iteratively annulling the pressure jumps at the trailing edge. Extensive convergence tests are carried out, and the influence of the wake model upon performance is studied. Predicted performance is shown to correlate well with the experiments.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.168-175
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• 2011

This study was conducted to examine the impacts of different soil water potentials on environmental soil properties related to the moisture injury of Korean raspberry (Rubus coreanus Miq.). Soil water potential in the plastic film house plots was differentiated from -5 to -40 kPa. Soils in the plots contained 5.6% of plant available water. Increasing soil water contents based on the changes in water potential increased soil pH and exchangeable $Ca^{2+}$ content and decreased exchangeable $K^+$ and total N contents. It also declined soil organic matter content at 9 days after water treatments. Relationship between water potential and soil water content was given as an exponential equation, y = 96.534 - 20.28In(x). In particular, when the water potential was higher than -20 kPa (27.5% of soil moisture content), it decreased chlorophyll content in the raspberry leaves, inhibited N uptake by the plant, and increased phosphorus content with increasing days after water treatment. Also, as the 7 days after water treatment at higher than -20 kPa of water potential, the root activity of the plant was significantly decreased, and trunk (top)/root (T/R) ratio of the plant markedly declined until 9 days after water supply. Carbohydrate contents in the raspberry plant leaves and roots at dormant stage were the lowest at -5 and -10 kPa of water potential plots, and it may cause winter injury to the plant.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.305-316
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• 2018

As the urbanization ratio increases, the heat environment in cities is becoming more important due to the urban heat island. In this study, the heat island spatial analysis was calculated and conducted for analysis of urban thermal environment of Sejong city, which was launched in 2012 and has been developed rapidly. To analyze the ratio and change rate of urban area, a multi temporal land cover map (2013 to 2015 and 2017) of study area is generated based on Landsat-8 OLI/TIRS (Operational Land Imager / Thermal Infrared Sensor) satellite imagery. Then, we select an TIR (Thermal Infrared) band from the two TIR bands provided by the Landsat-8, which is used for calculating the heat island potential, through the accuracy evaluation of the brightness temperature and AWS (Automatic Weathering Station) data. Based on the selected band and surface emissivity, land surface temperature is calculated and the estimated heat island potential change is analyzed. As a result, the land surface temperature of the high ratio and change rate of urban area was significantly higher than the surrounding area around $3^{\circ}C$ to $4^{\circ}C$, and the heat island potential was also higher around $4^{\circ}C$ to $5^{\circ}C$. However, the heat island phenomenon was alleviated in urban areas with high rate of change that also show high green area ratio. Therefore, we demonstrated that dense urban area increases the possibility of inducing heat island, but it can mitigate the heat island through green areas.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.5
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• pp.253-258
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• 2005

It is necessary to determine a nitrogen supplying capacity (NSC) of soil for sustainable agriculture. NSC has been decided by directly detecting N mineralization potential (NMP) and inorganic nitrogen or by indirectly approximating from organic matter and chemical properties of soil. NMP is best method for NSC but it takes long period. A study was conducted to find a short-term incubation method using pepsin through 1) determining NMP of 3 upland and 3 paddy soils, 2) establishing analytical condition of pepsin digestion by comparing to NMP, 3) validating with relations to N requirements for maximum yield of rice. NMPs of 6 soils were ranges from $63mg\;N\;kg^{-1}$ to $156mg\;N\;kg^{-1}$. The pepsin digestion method of soil nitrogen was established by determining amino nitrogen from digesting 5 g of soil for 30 minutes by 0.02% pepsin. This method was so highly correlated with a maximum rate of nitrogen fertilizer that it could be used for determining NSC in paddy soil.