• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.105-111
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• 1990

The soil adsorption coefficient of butachlor was measured mainly following the guidelines of U. S. EPA and OECD. The soil adsorption coefficient, Koc, of butachlor agreed well with the values in the literature. It was observed that soil adsorption differed about 5% with an increase or decrease by $15^{\circ}C$, implying that temperature does affect soil adsorption. The estimated value of the soil adsorption coefficient using water solubility and molecular structure deviated by factors of 2 and 20, respectively. The soil adsorption coefficient, Koc, of butachlor was 543 so this value means that butachlor is tightly bound to organic matter in soil and is considered immobile. A novel trial estimating the soil adsorption coefficient by molecular structure might be utilized to design efficient and/or non-polluting agrochemicals by organic chemists.

• Wind and Structures
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• v.31 no.3
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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.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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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.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.72-80
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• 2020

The information security industry is increasing in importance and market size due to the development of the fourth industry such as artificial intelligence, IoT and etc. This paper was analyzed the impact of the increasing information security industry on the domestic economy by using the Input-Output table. It was classified industrial sectors into information security products and information security services industries, and then reclassified the Input-Output table into 35 industries. And it was estimated the production inducement coefficient, the value-added inducement coefficient, employment inducement coefficient, and etc. The production inducement coefficients of the information security product and service industry are each 1.571, 1.802, and the value-added inducement coefficients of them are each 0.632, 0.997, and the employment inducement coefficients of them are each 2.494, 7.361. Only the value-added inducement coefficient of the information security service industry is slightly higher than the total industry, and the remaining inducement coefficients are all lower than the total industry. In addition, the information security product industry has no the forward and backward linkage effect, and the information security service industry has no the backward linkage effect. But it has the forward linkage effect. As a result of analyzing the economic ripple effect of the information security industry, the production inducement amounted to 359.9 trillion won, value-added inducement amounted to 164.8 trillion won, and employment inducement amounted to 803 thousand people.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.8-12
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• 1976

The major subjects of this experiment are to evaluate the mechanical properties of the curing gum for prevention of vibration and to study for related problems. In the prevention of vibration by the curing gum, the results are as follows. When the value of forced frequency over natural frequency is less than $\sqrt{2}$, it may well be used that the value$(1\%-2\%,\;4\%-5\%)$ of damping coefficient over critical damping coefficient of the curing gum is large. When the value of forced frequency over natural frequency is larger than $\sqrt{2}$, it may well be used that the value $(2.5\%-3.5\%)$ of the curing gum is low. If the larger value of logarithmic decrement may be used, the low curing gum is preferred. The conductive range of sulphur contents of the curing gum is $3.3\%-3.5\%$ in the light of phase angle, resilience, and damping coefficient over critical damping coefficient.

• The Korean Journal of Ceramics
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• v.2 no.1
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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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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• v.16 no.6
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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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• v.8 no.7
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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.

• The Korean Journal of Applied Statistics
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• v.35 no.3
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• pp.421-434
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• 2022

Chatterjee (2021) proposed a new correlation coefficient ξ. Focusing on two questions (1. Is ξ coefficient distinguishable for Anscombe's quartet data set?, 2. How does the ξ coefficient value change according to the number of data for various kinds of scatterplots?), an exploratory data analysis is attempted for ξ coefficient. We can compare three measures (ξ coefficient, Pearson's correlation coefficient and mutual information).