• 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.

• Wind and Structures
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• 제31권3호
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• pp.197-207
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• 2020

Knowledge on the design value of extreme wind pressure coefficients (EWPC) of a specific zone of buildings is essential for the wind-resistant capacity of claddings. This paper presents a method to estimate the representative EWPC introducing the multivariate extreme value model. The spatial correlations of the extreme wind pressures at different locations can be consider through the multivariate extreme value. The moving average method is also adopted in this method, so that the measured point pressure can be converted to wind pressure of an area. The proposed method is applied to wind tunnel test results of a large flat roof building. Comparison with existing methods shows that it can give a good estimation for all target zones with different sizes.

• 한국산업융합학회 논문집
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• 제24권3호
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• pp.307-313
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• 2021

In this study, the comparative analysis, among the design standard value of distribution power, the calculated value from the measurement data of strand and the empirical data of the distribution line itself, have been performed for the elastic coefficients and linear expansion coefficients of distribution line conductors. The empirical values of elastic coefficients were lower about 10.6%(892kgf/mm²) than those of the design standard value of the distribution power and there were a little difference between the empirical values of linear expansion coefficients and the design standard value of the distribution power. From the above results, it could be concluded that the empirical values of conductor characteristics should be used in the dip design and installation of distribution line.

• 한국정보전자통신기술학회논문지
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• 제13권1호
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• pp.72-80
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• 2020

인공지능, IoT 등의 4차 산업의 등장으로 정보화는 가속화됨에 따라 정보보호 산업의 중요성과 시장의 규모가 증가하고 있다. 본 논문에서는 증가하는 정보보호 산업이 국내 경제에 미치는 영향을 산업연관표를 이용하여 분석하였다. 본 논문에서는 산업부문을 정보보호 제품산업과 정보보호 서비스 산업을 분류한 후에, 35개의 산업으로 산업연관표를 재분류하였고, 생산유발계수, 부가가치유발계수, 고용유발계수 등을 산출하였다. 정보보안 제품산업과 정보보안 서비스 산업의 생산유발계수는 각각 1.571, 1.802이고, 부가가치유발계수는 각각 0.632, 0.997이고, 고용유발계수는 각각 2.494, 7.361이다. 정보보호 서비스 산업의 부가가치유발계수만이 전체 산업보다 다소 높고, 나머지 유발계수는 모두 전체 산업보다 낮게 나타났다. 그리고 정보보호 제품산업에는 전·후방연쇄효과가 없고, 정보보호 서비스 산업에는 후방연쇄효과는 없으나 전방연쇄효과는 있는 것으로 나타났다. 정보보호 산업의 경제적 파급효과를 분석한 결과, 생산유발액은 359.9조원, 부가가치유발액은 164.8조원에 달하고, 803천명의 고용을 유발하는 것으로 나타났다.

• 한국수산과학회지
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• 제9권1호
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• pp.8-12
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• 1976

1. 진동방지에는 $W/W_n<\sqrt{2}$일 때는 $C/_cC$가 큰 유화고무$(1\~2\%,\;4\~5\%)$가 좋다. 2. $W/W_n<\sqrt{2}$ 일때는 $C/_cC$가 작은 유화고무$(2.5\%\~3.5\%)$가 좋다. 3. 대수감쇠율의 값을 크게 하려면 저유화 고무가 좋다. 4. $\phi$ 및 R, $C/_cC$를 감안해서 $2.5\%\~3.5\%$의 유화 고무가 좋다. 5. $5\%이상$의 유화고무는 과유화관계상 좋지 못하다.

• The Korean Journal of Ceramics
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• 제2권1호
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• pp.11-18
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• 1996

The variation of electrical conductively and Seebeck coefficient of FeSi2 according to the density of the specimen has been observed over the temperature range 50 to $700^{\circ}C$. A conventional pressureless sintering method with various sintering time (0, 0.5, 1, 5h) at $1190^{\circ}C$ and/or various sintering temperatures(1160, 1175, 1190, $1200^{\circ}C$) for 2 h was carried out to prepare $FeSi_2$ specimens having various densities. The relationship between the electrical conductivity and Seebeck coefficient was investigated after two steps of annealing (at $865^{\circ}C$ and then $800^{\circ}C$ for total 160h) and thermoelectric measurement. The electrical conductivity for the specimens showed a typical tendency of semiconductor, the average activation energy of which in the intrinsic region (above $300^{\circ}C$) was observed approximately as 0.452 eV, and increased slightly with density. On the other hand, the specimen of the lower density showed the higher value of Seebeck coefficient in the intrinsic region. As the temperature fell into the non-degenerate region, the highly densified specimen which had relatively little residual metal phase showed the higher value of Seeback coefficient. The power factor of all specimens showed the optimum value at $200^{\circ}C$. However, the power factor of the specimen of the lower density increased again from $400^{\circ}C$ and that of the higher dense specimen increased from $500^{\circ}C$. The power factor was more affected by Seebeck coefficient than electrical conductivity over all temperature range.

• 한국기계가공학회지
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• 제18권3호
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• pp.103-108
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• 2019

The results of the measurement of the flow-rate coefficient (Cv-value) and the analysis of a small ball valve are summarized follows. The Cv-values of 1/2-, 3/4- and 1-inch ball valves were measured using a flow-rate measurement test. The manufacturer obtained the Cv-value using a theoretical calculation method. The new experimental measurement and analysis method yielded more reliable results. In addition, the Cv value obtained through numerical analysis was almost identical the value provided by the manufacturer, which was based on experimental results. A Study on Flow Analysis results are all similar appearances as the reliability of the results.

• Journal of Information Processing Systems
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• 제16권6호
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• pp.1343-1358
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• 2020

In the stagewise arithmetic orthogonal matching pursuit algorithm, the weak threshold used in sparsity estimation is determined via maximum iterations. Different maximum iterations correspond to different thresholds and affect the performance of the algorithm. To solve this problem, we propose an improved variable weak threshold based on the stagewise arithmetic orthogonal matching pursuit algorithm. Our proposed algorithm uses the residual error value to control the weak threshold. When the residual value decreases, the threshold value continuously increases, so that the atoms contained in the atomic set are closer to the real sparsity value, making it possible to improve the reconstruction accuracy. In addition, we improved the generalized Jaccard coefficient in order to replace the inner product method that is used in the stagewise arithmetic orthogonal matching pursuit algorithm. Our proposed algorithm uses the covariance to replace the joint expectation for two variables based on the generalized Jaccard coefficient. The improved generalized Jaccard coefficient can be used to generate a more accurate calculation of the correlation between the measurement matrixes. In addition, the residual is more accurate, which can reduce the possibility of selecting the wrong atoms. We demonstrate using simulations that the proposed algorithm produces a better reconstruction result in the reconstruction of a one-dimensional signal and two-dimensional image signal.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.383-391
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• 2021

This study examines the connectedness between the number of COVID-19 cases in Thailand and trading value among investors in the Stock Exchange of Thailand. Daily data of COVID-19 cases and trading value were sourced from the Thailand ministry of public health and the Stock Exchange of Thailand, from January 12, 2020 to May 11, 2021. This study applies a multiple linear regression analysis to explain the relationship between variables. Empirical evidence clearly shows that the volatility of trading value was affected by COVID-19's new, confirmed, and deaths cases within the first pandemic period more than during the second pandemic period. Nevertheless, during the third pandemic period there is no evidence that the new, confirmed, and deaths cases significantly influenced trading value. Furthermore, the results show that COVID-19's new and deaths cases have a negative coefficient that indicated the trading value-buy/sell decreased in response to COVID-19's new and deaths cases, whereas the confirmed COVID-19 cases have a positive coefficient that indicated the trading value-buy/sell increased in response to COVID's confirmed cases. In summary, this study suggests that the number of COVID-19 cases have a significant impact on the trading value in the short term more than in the intermediate and long term.

• 응용통계연구
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• 제35권3호
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• pp.421-434
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• 2022

Chatterjee (2021)는 새로운 상관계수 ξ를 제안하였다. 두 가지 질문 (1. Anscombe's quartet 데이터셋에 대하여 ξ 계수는 구별이 가능한가?, 2. 다양한 종류의 산점도에서 데이터의 개수에 따라 ξ 계수 값의 변화는 어떠한가?)을 중심으로 ξ 계수에 대한 탐색적자료분석을 시도하였다. 세 가지 측도 (ξ 계수, 피어슨상관계수, 상호정보)를 서로 비교하였다.