• 구강회복응용과학지
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• 제19권2호
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• pp.87-96
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• 2003

The purposes of this study were to find out the optimum intensity of magnetic field where magnetism could promote the activity of osteoblast, and to discover the possibility of clinical application in the areas of dental implants and bone grafts by confirming the effect of clinically increasing bone formation. In this experiment, we used the Neodymium magnet, which had magnetic power six times as strong as the current ones and enabled the resistances against the demagnetization up to 20 to 50 times to be minimized with the size of 1mm in sight. In order to culture cells, a specially designed device was used. It was made to adjust the distance and accordingly to control the intensity of the magnetic field, by placing the cell culture plate in the center with a magnet of 1mm long and thick installed on the both ends. Using MC3T3-E1 cell, a kind of osteoblast-like cell, we cultured, for 24 hours, not only the test group which had been cultured under the magnetic fields with different intensity of 5, 10, 50, 100, 500, and 1000 Gauss, but also the control group excluding the influences of the magnetic field. After observing the cell's form and the density of the culture medium through an inverted microscope, we made a series of proceedings needed for the immunofluoroscence staining, such as fixation, normal serum reaction, primary antibody reaction, and secondary antibody reaction. And with a fluorescence microscope, we observed those-above and compared the frequency of expression of IFG-1 receptor. To make a Western immunoblotting analysis, the cells cultured under the same condition as the above had the procedure of the lysis buffer and the acrylamide gel electrophoresis was carried out. Protein transferred into the nitrocellulose membrane and tested on the primary and the secondary antibody reactions was observed and compared. The results were as follows: When observed through an inverted microscope, the nuclear divisions of the cells under the magnetic field of 10 Gauss were the most active, and the density of the cells could be observed the most enormously. As the result of an immunofluoroscence staining of IGF-1 receptor, the expression of IFG-1 was the most frequently observed under the magnetic field of 10 Gauss. On the other hand, few differences of consideration were made between the test group cultured under the magnetic fields of 5, 500, and 1000 Gauss and the control group. In respect of the expression of IFG-1 receptor, the test group cultured under the magnetic fields of 50 and 100 Gauss were higher than the control group, and lower than that cultured under the magnetic field of 10 Gauss.(p<0.05) According to the Western immunoblotting analysis, the band of IFG-1 receptor which had 85KDa of molecular weight was the darkest. Judging from the above-mentioned results, the growth factor receptor of an osteoblast cell which was an important criterion for the bone formation was increased in maximum under the magnetic field of 10 Gauss. Moreover it was observed that the optimum intensity of magnetic field in which magnetism made the activity of the osteoblast cell increase was about 10 Gauss.

• 대한토목학회논문집
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• 제5권4호
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• pp.121-127
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• 1985

본 논문(論文)에서는 경위도(經緯度) 좌표(座標)(${\varphi}$, ${\lambda}$)에 의해 측지망(測地網)을 동시조정(同時調整)하는 컴퓨터 프로그램을 작성하고, 1점(點) 1방향(方向) 고정(固定)인 경우와 자유망(自由網)조정의 두 경우를 검토하였다. 구성과(舊成果)를 초기치(初期値)로 이용하고 Hubeny 에 의해 확장된 Gauss 의 평균위도식(平均緯度式)을 사용하였으며, 좌표조정법(座標調整法)에 의해 조정계산(調整計算)을 실시하였다. 기준타원체(基準楕圓體)로는 Bessel 치를 사용하고, 관측(觀測)에 대한 중량(重量)을 1로 가정하였다. 우리 나라 일부지역의 실측(實測)데이타를 적용한 결과 평균위치오차(平均位置誤差)가 1점 1방향 고정의 경우 6.2cm, 자유망(自由網)의 경우는 2.4cm로 나타났다. 적용된 삼변망(三邊網)의 단위중량(單位重量)에 대한 표준오차(標準誤差)는 $1.66{\times}10^{-6}$ 라디안 (0.3")이고, 오차타원(誤差楕圓)을 분석한 결과 자유망(自由網)이 오차분배면에서 효과적임을 보여 주고 있다.

• Toxicological Research
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• 제17권4호
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• pp.279-286
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• 2001

Recently, there is an increasing nationwide concern in Korea that exposure to electric and magnetic fields in the home environment may not be safe in humans. To identify possible effects of horizontally polarized magnetic fields (MF) exposure on embryo-fetal development, timed-mated female Sprague-Dawley rats (24/group) received continuous exposure to 60 Hz MF at field strengths of 0 Gauss (sham control), 50mG,833 mG, or 5000 mG. Dams received MF of sham exposures for 22hr/day on gestation days 6 through 20. Experimentally generated MF were monitored continuously througout the study. There was no evidence of maternal toxicity of developmental toxicity in any MF-exposed groups. Mean maternal body weight, organ weights, and gross findings in groups exposed to MF did not differ from those in sham control. No significant differences in fetal deaths, fetal body weight, and placental weight were observed between MF-exposed groups and sham control. External, visceral, and skeletal examination of fetuses demonstrated no significant differences in the incidence of fetal malformations between MF-exposed and sham control groups. In conclusion, exposure of pregnant Sprague-Dawley rats to 60 Hz at MF strengths up to 5000 mG during gestation day 6-20 did not produce any biologically significant effect in either dams of fetuses.

• 한국해안·해양공학회논문집
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• 제22권6호
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• pp.387-396
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• 2010

해저 지중 피압유체의 3차원 전이류에 대한 수치모형이 개발되었다. 개발된 모형은 FDM 모형으로서 Gauss-Seidel SOR(successive over-relaxation)을 사용하는 것을 특징으로 한다. 본 모형으로 산출된 수두분포는 Theis의 해석해와 비교하여 작은 오차범위 내에서 동일하였다. 또한 MODFLOW 모형을 이용한 산출도 근접한 결과를 보여주었다. 대수층의 측면유입량과 우물의 양수량을 비교하였으며, 이 경우 가중치 ${\alpha}$가 mass balance에 영향을 주는 것으로 확인되었다. 즉, 완전음해법(${\alpha}$=1)에서는 약 5%의 오차를 보여주었다. 그러나 ${\alpha}$가 점점 감소하면서 0.5(Crank and Nicolson method)에 이르기까지, mass balance는 연속적으로 악화되며, 모형 결과는 발산한다. 또한 $\lambda$(over-relaxation factor)에 따른 수렴속도는 ${\lambda}=0.8{\sim}1.5$에서 큰 차이가 없었으나 $\lambda$가 1.5를 초과하는 경우 모형 결과는 발산한다. 다중 우물 설치시 양수량 변화가 산출되었다. 즉, 우물 상호간의 위치가 너무 근접하게 되면 양수량을 저하시킨다. 본 모형은 이방성$(Kx{\neq}Ky{\neq}Kz)$과 비균질성을 고려할 수 있으며, 다양한 경계 조건을 설정함으로서 현장조건을 반영할 수 있다. 따라서 3차원 피압 전이류에서, 우물의 위치 선정, 양수량 산출, 인공주입에 따른 흐름의 거동예측 등에 효과적으로 이용될 수 있을 것으로 사료된다.

• 한국토양비료학회지
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• 제38권2호
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• pp.78-84
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• 2005

국내에서 자가 채종되는 양파종자의 품종, 종자의 함수량 및 종자크기가 발아율에 미치는 영향과 gibberellin, $KNO_3$ 및 $NaNO_3$ 등의 화학약품, 및 전기장과 자기장 처리가 발아율과 초기생육에 미치는 영향을 조사하였다. 종자의 품종에 따른 발아율의 변화는 거의 없었으나, 채종 후 저장 또는 건조정도에 따라 큰 차이를 나타내었다. 종자의 함수량이 10-15% 범위에서 발아율이 가장 높았으며, 대립종자보다는 중립과 소림종자의 발아율이 높게 나타났다. 화학약품을 처리한 종자의 발아율 GA < $NaNO_3$ < $KNO_3$ 순으로 높게 나타났다. $KNO_3$ 0.1%와 0.2% 처리로 최종발아율이 10-12% 증가하였으며, nitrate가 양파종자의 발아촉진 및 발아율 향상에 효과적인 것으로 나타났다. 전기장 또는 자기장 처리에 의해 양파종자의 발아율이 향상되었으며, 전기장 10 kV와 자기장 4 Gauss 처리시 각각 86%와 88%로 무처리구에 비해 10-12% 높았다. 또한 전기장과 자기장 처리로 양파종자의 초기생육은 향상되었으며, 파종 40일 후의 초장 및 생체중량이 무처리구에 비해 23-45% 증가되었다.

• 대한기계학회논문집A
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• 제29권2호
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• pp.201-213
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• 2005

The automotive door has a large finite element model in analysis and many design requirements such as stiffness, natural frequency, side intrusion, etc. Thus, various related governing equations should be solved for systematic analysis and design. Because each governing equation has different characteristics, it is almost impossible to solve them simultaneously. Instead, they are separately handled and the analysis results are incorporated into the design separately. Currently, the design is usually conducted by trials and errors with engineering intuition in design practice. In this research, MDO methods are proposed to solve the problems that share design variables in disciplines. The idea is from the Gauss-Seidel type method for multi-discipline analysis. The developed methods show stable convergence and the weight of the door is reduced by fifteen percent.

• 대한수학회지
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• 제48권2호
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• pp.267-288
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• 2011

In this paper, we construct eight infinite families of ternary linear codes associated with double cosets with respect to certain maximal parabolic subgroup of the special orthogonal group $SO^-$(2n, q). Here q is a power of three. Then we obtain four infinite families of recursive formulas for power moments of Kloosterman sums with square arguments and four infinite families of recursive formulas for even power moments of those in terms of the frequencies of weights in the codes. This is done via Pless power moment identity and by utilizing the explicit expressions of exponential sums over those double cosets related to the evaluations of "Gauss sums" for the orthogonal groups $O^-$(2n, q).

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (2)
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• pp.321-323
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• 1998

이 논문에서는 크기가 큰 III-Conditioned Matrices 정방행렬의 좌측 또는 우측 역행렬 계산시 계산상의 정확도를 향상시키는 알고리듬에 대하여 기술한다. 이 알고리듬은 대상 행렬의 행벡터들을 Input으로 하고 해당 Input 벡터가 몇번째 행 벡터인지를 나타내는 단위 벡터를 Target 벡터로 하며 초기 Weight 값으로 Pivoting을 겸한 Gauss소거법을 적용하여 얻은 역행렬을 사용하는 Single Layer 인공신경망에 적용하는 역전파 알고리듬과 흡사한 것이다. 각각의 Input 행 벡터에 대하여 역행렬의 열 벡터들이 점진적으로 직교가 되거나 평행이 되도록 근접시키므로써 모든 Input 행 벡터들이 열벡터들에 비교적 균일하게 직교 또는 평행이 되도록 학습시키는 알고리듬이다.

• ETRI Journal
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• 제44권5호
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• pp.769-779
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• 2022

Spectral clustering has become a typical and efficient clustering method used in a variety of applications. The critical step of spectral clustering is the similarity measurement, which largely determines the performance of the spectral clustering method. In this paper, we propose a novel spectral clustering algorithm based on the local similarity measure of shared neighbors. This similarity measurement exploits the local density information between data points based on the weight of the shared neighbors in a directed k-nearest neighbor graph with only one parameter k, that is, the number of nearest neighbors. Numerical experiments on synthetic and real-world datasets demonstrate that our proposed algorithm outperforms other existing spectral clustering algorithms in terms of the clustering performance measured via the normalized mutual information, clustering accuracy, and F-measure. As an example, the proposed method can provide an improvement of 15.82% in the clustering performance for the Soybean dataset.

• 한국공간구조학회논문집
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• 제21권4호
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• pp.49-56
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• 2021

This study aims to develop a form-finding algorithm for a single-layered pneumatic membrane. The initial shape of this pneumatic membrane, which is an air-supported type pneumatic membrane, is to find a state in which a given initial tension and internal pneumatic pressure are in equilibrium. The algorithm developed to satisfy these conditions is that a nonlinear optimization problem based on the force method considering the deformed shape is formulated, and, it's able to find the shape by iteratively repeating the process of obtaining a solution of the governing equations. An computational technique based on the Gauss-Newton method was used as a method for obtaining solutions of nonlinear equations. In order to verify the validity of the proposed form-finding algorithm, a single-curvature pneumatic membrane example and a double-curvature air pneumatic membrane example were adopted, respectively. In the results of these examples, it was possible to well observe the step-by-step convergence process of the shape of the pneumatic membrane, and it was also possible to confirm the change in shape according to the air pressure. In addition, the calculation results of the shape and internal force after deformation due to initial tension, air pressure, and self-weight were obtained.