• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.137-140
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• 2002

The algorithm for calculating the base-collector breakdown voltage of NPN BJT(Bipolar Junction Transistor) for integrated circuits is proposed. The method for calculating the electric field using the solution of Poisson's equation is presented and the method for calculating the breakdown voltage using the integration of ionization coefficients is presented. The base-collector breakdown voltage of NPN BJT using 20V process obtained from the proposed method shows an averaged relative error of 8.0% compared with the measured data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.141-144
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• 2002

The method of the analysis of the base Gummel number of the PNP BJT(Bipolar Junction Transistor) for integrated circuits based upon the semiconductor physics is proposed and the method of calculating the doping profile of the base region using process conditions is presented. The transistor saturation current obtained from the proposed method of PNP BJT using 20V and 30V process shows an averaged relative error of 6.7% compared with the measured data.

• Water Engineering Research
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• 제4권1호
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• pp.45-58
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• 2003

Two-dimensional depth-averaged advection-dispersion equation was simulated using FEM. In the straight rectangular channel, the advection-dispersion processes are simulated so that these results can be compared with analyti-cal solutions for the transverse line injection and the point injection. In the straight domain the standard Galerkin method with the linear basis function is found to be inadequate to the advection-dispersion analysis compared to the upwind finite element scheme. The experimental data in the S-curved channel were compared with the result by the numerical model using SUPG(Streamline upwind Petrov-Galerkin) method.

• Journal of Ship and Ocean Technology
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• 제5권1호
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• pp.38-54
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• 2001

A finite difference method for calculating turbulent flow and surface wave fields around a ship model is evaluated through the comparison with the experimental data of a Series 60 $C_B$=0.6 ship model. The method solves the Reynolds-averaged Navior-Stokes Equations using the non-staggered grid system, the four-stage Runge-Kutta scheme for the temporal integration of governing equations and the Bladwin-Lomax model for the turbulence closure. The free surface waves are captured by solving the equation of the kinematic free-surface condition using the Lax-Wendroff scheme and free-surface conforming grids are generated at each time step so that one of the grid surfaces coincides always with the free surface. The computational results show an overall close agreement with the experimental data and verify that the present method can simulate well the turbulent boundary layers and wakes as well as the free-surface waves.

• 천문학회보
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• 제44권2호
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• pp.75.1-75.1
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• 2019

We introduce a novel method for reconstructing the projected dark matter mass maps of merging galaxy clusters by applying the convolutional neural network (CNN) to their weak lensing maps. We generate synthesized grayscale images from given weak lensing maps that preserve their averaged galaxy ellipticity. We then apply them to multi-layered CNN with architectures of alternating convolution and trans-convolution filters to predict the mass maps. We train our architecture with 1,000 Subaru/Suprime-Cam mock weak lensing maps, and our method have better mass map prediction than the Kaiser-Squires method with the following three aspects: (1) better pixel-to-pixel correlation, (2) more accurate finding of density peak position, and (3) free from mass-sheet degeneracy. We also apply our method to the HST weak lensing map of the El Gordo cluster and compare our result to the previous studies.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.562-568
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• 2020

This study investigates the relationship between ultrasonic velocity and density in the direct method, the effect of distance between transducers in the indirect method, and the difference between the direct and indirect methods with transducers placed at a distance of 200 mm in nondestructive ultrasonic testing of spruce lumber. The direct method using 54 kHz ultrasonic transducers was applied to two planes, namely, radial section (LR) and tangential section (LT) of samples. The indirect method measurements were taken using the same transducers. Two velocities were measured at the top and bottom of the LT plane and at the two sides of the LR plane; the two values for each plane were averaged. The relationship between density and ultrasound velocity in the direct method demonstrated a positive correlation between the two variables. The difference between the two planes, LT and LR, was not statistically significant. Moreover, the distance between the transducers in the indirect method affected ultrasound velocity, with the ultrasonic velocity increasing as the distance between the transducers became larger. A transducer distance of 200 mm yielded a close approximation of the direct method results with a ratio of 0.87. Finally, no statistical evidence of a difference between the two planes in the indirect method was found. If the direct method, which requires access to two surfaces, is impractical, the indirect method can be applied.

• 대한족부족관절학회지
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• 제9권2호
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• pp.162-166
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• 2005

Purpose: To analyze the clinical and radiological feature of Os subfibulare and to evaluate the results after anatomical reduction and internal fixation with bone graft for Os subfibulare. Materials and Methods: Forty-two cases, which underwent anatomic reduction and bone graft for Os subfibulare from October 1998 to September 2004 were reviewed. We analysed preopertive symptoms and onset of symptoms and radiologically measured the size and amounts of displacement of Os subfibulare under the inversion stress. Postoperatively we evaluated the clinical results measured by Hasegawa method and evidence of union. Results: Preoperatively there were only pain around the lateral malleolus in 16 cases, only instability of ankle joint in 3 cases, and pain and instability in 23 cases. The age of symptom onset averaged 23 years(range, 13-38 years). Radiographically Os sufibulare anteriorly located from lateral malleolus were in 40 cases, posteriorly situated in 2 cases. The size of Os subfibulare ranged from $1{\times}4\;mm$ to $8{\times}17\;mm$. In 22 cases of inversion stress view, displacement of the Os sbufibulare averaged $1.5{\pm}1.1\;mm$ (0 to 5 mm). The postoperative clinical results were excellent in 41 cases, poor in 1 case. There were complications of 1 case of irritation of sural nerve, 1 case of nonunion. Conclusion: Anatomic reduction and bone graft is effective treatment method for symptomatic Os subfibulare.

• 수산해양기술연구
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• 제47권3호
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• pp.214-221
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• 2011

This study was performed to develop a video based system which can be used to measure the averaged fish size in a non-intrusive fashion. The design was based on principles of simple stereo geometry, incorporated fish dimensions weight relationships and took into consideration fish movement to lower system costs. As the fish size is an important factor that impacts the economy of an aquaculture enterprise. Size measurements, including fork length, width or height, girth, thickness and mass, can be used to determine fish condition in the fish farm, so the averaged fish size of fish cage needs to consistently monitor in open ocean aquaculture cage. A precision of ${\pm}3%$ for replicate length measurements of a 60cm bar is obtained at distances between 2.0 and 6.0m, and the mean fork length and mean swimming speed of bluefin tuna were estimated to 48.8cm and 0.78FL/s, respectively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.143-148
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• 2005

The main purpose of this study is to suggest and evaluate an operational method for assessing the potential impact of climate change on hydrologic components and water resources of regional scale river basins. The method, which uses large scale climate change information provided by a state of the art general circulation model(GCM) comprises a statistical downscaling approach and a spatially distributed hydrological model applied to a river basin located in Korea. First, we construct global climate change scenarios using the YONU GCM control run and transient experiments, then transform the YONU GCM grid-box predictions with coarse resolution of climate change into the site-specific values by statistical downscaling techniques. The values are used to modify the parameters of the stochastic weather generator model for the simulation of the site-specific daily weather time series. The weather series fed into a semi-distributed hydrological model called SLURP to simulate the streamflows associated with other water resources for the condition of $2CO_2$. This approach is applied to the Yongdam dam basin in southern part of Korea. The results show that under the condition of $2CO_2$, about $7.6\% of annual mean streamflow is reduced when it is compared with the observed one. And while Seasonal streamflows in the winter and autumn are increased, a streamflow in the summer is decreased. However, the seasonality of the simulated series is similar to the observed pattern and the analysis of the duration cure shows the mean of averaged low flow is increased while the averaged wet and normal flow are decreased for the climate change.

• 한국수정란이식학회지
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• 제11권3호
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• pp.211-216
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• 1996

A series of experiments were designed to determine the feasibility of single dose of FSH as an effective superovulation method in rabbits. The superovulation treatments examined comparatively were as follows: 1) a single injection of 100 IU PMSG, 2) Multiple injections of 1 IU Super-OV of 2X daily for 3 days, 3) Multiple injections of 6.6 rng Folltropin-V 2X daily for 3 days, 4) Multiple injections of 13.3 rng Folltropn-V l$\times$ daily for 3 days, 5) Single injection of 40 mg Folltropin-V solved in 10% PVP, and 6) Single injection of 40 mg Folltropin-V dissolved in 25% PVP. The results obtained were as follows: The nurnher of ovulation points in the single injection of 40 mg Folltropin-V dissolved in 25% PVP and multiple injections of 6.6 mg Folltropin-V 2X daily for 3 days was averaged 44.6 and 39.2, respectively, which were significantly (P<0.05) more than in a single dose of PMSG or multiple doses of Super-OV. The number of total ova recovered in the single injection of 40 mg Folltropin-V dissolved in 25% PVP and multiple injections of 6.6 mg Folltropin-V 2X daily for 3 days was averaged 30.4 and 25.9, respectively, which were significantly (P<0.05) more than in the single dose of PMSG or multiple doses of Super-OV. A similar result was obtained for the number of fertilized ova recovered from the above six treatments. From the above results it was concluded that a single injection of 40 mg Folltropin-V dissolved in 25% PVP could be an effective and simple method for superovulation in rabbits.