• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1617-1619
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• 2000

In this study the nonlinear dielectric properties of amorphous copolymers were analyzed by the related nonlinear dielectric theory. The theory is related to the cooperated dipoles and the number of the dipoles. The relation between the polarization coefficient $R_p$ and the nonlinear coefficient $R_s$ was deduced under the assumption of isotropic media.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.614-618
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• 2016

본 논문은 EDISON_CFD를 활용하여 화성에서 운용 가능한 풍력터빈에 대해 실험 및 개선 설계하였다. 본 연구에서는 화성의 중력 및 공기밀도 등 화성의 환경 데이터를 적용함으로써 풍력터빈의 형상을 새롭게 설계 하였다. 개선 설계는 기존의 풍력발전기 형상을 변형시키며 해석을 진행하였으며, 받음각과 형상에 따라 생성되는 토크를 확인하였다. 개선설계한 풍력터빈 모델은 단위 미터 당 약 8 W의 전력생산이 가능한 것을 확인하였다.

• Kyungpook Mathematical Journal
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• 제59권3호
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• pp.493-503
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• 2019

In the present investigation, we define two new subclasses of analytic and m-fold symmetric bi-univalent functions defined by a linear combination in the open unit disk U. Furthermore, for functions in each of the subclasses introduced here, we establish upper bounds for the initial coefficients ${\mid}a_{m+1}{\mid}$ and ${\mid}a_{2m+1}{\mid}$. Also, we indicate certain special cases for our results.

• 호남수학학술지
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• 제40권4호
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• pp.733-748
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• 2018

In this paper, we investigate a new subclass $S^{{\varphi},{\lambda}}_{{\Sigma}_m}$ of ${\Sigma}_m$ consisting of analytic and m-fold symmetric bi-univalent functions satisfying subordination in the open unit disk U. We consider the Fekete-$Szeg{\ddot{o}}$ inequalities for this class. Also, we establish estimates for the coefficients for this subclass and several related classes are also considered and connections to earlier known results are made.

• Kyungpook Mathematical Journal
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• 제53권3호
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• pp.467-478
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• 2013

The purpose of the present paper is to establish some interesting results involving coefficient conditions, extreme points, distortion bounds and covering theorems for the classes $V_H({\beta})$ and $U_H({\beta})$. Further, various inclusion relations are also obtained for these classes. We also discuss a class preserving integral operator and show that these classes are closed under convolution and convex combinations.

• 대한수학회논문집
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• 제13권4호
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• pp.875-888
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• 1998

The use of the zeros of Chebyshev polynomial of the first kind $T_{4n＋4(x}$ ) and second kind $U_{2n＋1}$ (x) for Gauss-Chebyshev quad-rature and collocation of singular integral equations of Cauchy type yields computationally accurate solutions over other combinations of $T_{n}$ /(x) and $U_{m}$(x) as in [8]. We show that the coefficient matrix of the overdetermined system has the generalized inverse. We estimate the residual error using the norm of the generalized inverse.e.

• 한국환경농학회지
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• 제9권2호
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• pp.105-111
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• 1990

제초제 butachlor의 토양흡착 실험을 수행한 결과 다음과 같은 결론을 얻었다. 1. Freundlich 방정식으로 구한 butachlor의 흡착상수 K 값은 9.78이었고 1/n값은 0.79였다. 이 때 correlation coefficient는 0.992였다. K값으로부터 유기물 함량을 감안하여 계산된 Koc값은 543이었다. 이 수치는 기존 문헌치와 거의 일치하였다. 2. 온도변화에 따른 흡착량은 온도가 증가할수록 흡착량도 증가하는 경향을 보였으며 $15^{\circ}C$ 온도변화에 대한 흡착량의 변화는 5%정도였다. 3. Computer program을 이용하여 토양 흡착계수를 추정한 결과 실험치와 20배 정도의 차이를 보이나 실험을 수행하기전 토양흡착계수를 예측하는데 있어서는 활용 가능성이 있음을 확인하였다. 4. Butachlor는 비교적 토양에 흡착이 잘되는 화합물로 판정되었다.

• 대한토목학회논문집
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• 제29권4D호
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• pp.459-465
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• 2009

u-Transportation (u-T) 환경은 차세대의 ITS로 간주되는 미래형 교통서비스로서 어디에서나 적절한 교통서비스를 제공하는 신 교통공간을 의미한다. 그러한 환경의 기초연구로서 본 연구는 기존 ITS에서 교통량 산출 방법을 검토하고, u-T 자료 수집환경(u-TSN)의 자료수집형태를 시뮬레이션으로 구현하여 ITS의 교통량 산정 결과와의 차이점을 연구하였다. 그 결과, u-T에서 단속류의 교통류율이 ITS보다 3.58% 높게 나타났으며, 평가지표 MARE와 MAE 값이 각각 31.4%, 31.1% 낮게 나타나고, 평가지표 균등계수는 1.9% 높게 나타나 상대적으로 u-TSN의 교통자료 집계가 더 우수함을 알 수 있었다. 이는 상류부 링크의 특정지점 교통량을 고려하지 못한 기존 방법론에 비해, u-T에서의 링크 특성이 잘 반영된 링크의 대표치라는데 의의 또한 있는바, 설계시간계수 등의 설계분야, 운영 분야 등에 보다 적절한 교통류율의 제공이 가능할 것으로 판단된다.

• 대한의용생체공학회:의공학회지
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• 제44권5호
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• pp.354-361
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• 2023

Most of spinal diseases are diagnosed based on the subjective judgment of a specialist, so numerous studies have been conducted to find objectivity by automating the diagnosis process using deep learning. In this paper, we propose a method that combines segmentation and feature extraction, which are frequently used techniques for diagnosing spinal diseases. Four models, U-Net, U-Net++, DeepLabv3+, and M-Net were trained and compared using 1000 X-ray images, and key-points were derived using Douglas-Peucker algorithms. For evaluation, Dice Similarity Coefficient(DSC), Intersection over Union(IoU), precision, recall, and area under precision-recall curve evaluation metrics were used and U-Net++ showed the best performance in all metrics with an average DSC of 0.9724. For the average Euclidean distance between estimated key-points and ground truth, U-Net was the best, followed by U-Net++. However the difference in average distance was about 0.1 pixels, which is not significant. The results suggest that it is possible to extract key-points based on segmentation and that it can be used to accurately diagnose various spinal diseases, including spondylolisthesis, with consistent criteria.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.860-863
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• 2002

Realizations of multirate converters are proposed using periodically time-varying (PTV) structures. By exploiting the computational redundancy of the filtering operation in a multirate filter, it is possible to implement the filter with much less hardware. In the proposed implementations, several coefficients time-share in a periodic fashion the hardware of one multiply-and-add. Therefore, each multiply-and-add circuit performs different coefficient scalings at different time instants within a period. Compared to the direct form realization, the proposed realizations reduce the hardware of an interpolator and a decimator by a factor of approximately U and M, respectively, while retaining the same processing speed, where U and M are the upsampling and downsampling factors, respectively. The approach can be used to obtain realizations for sampling rate conversion by a rational factor of U/M, where U and M are relatively prime, in which case hardware reduction by a factor of approximately UM can be achieved.