• Communications of Mathematical Education
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• v.28 no.2
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• pp.281-302
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• 2014

The purpose of this paper is to offer a history of golden ratio, the criterion raised by Markowsky, and misconceptions about golden ratio. Markowsky(1992) insists that the golden ratio does not appear in the great pyramid of Khufu. On the contrary, we claim that there exists the golden ration on it. Elementary and middle school text books, and domestic history books deal with the great pyramid of Khuff and the Parthenon by examples of the golden ratio. Text books make many incorrect statements about golden ratio; so in teaching and learning the golden ratio, we recommend the design-composition of dynamic symmetry, for example, industrial design, aerodynamic, architecture design, and screen design. Finally we discuss the axial age how to affect the school mathematics with respect to the subject of Thales and the golden ratio.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.206-214
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• 2020

This study analyzed the impact of direct and indirect subsidies on profitability in general hospitals in Korea. The data were collected from medical institution accounting information disclosure system of 270 general hospitals from 2016 to 2018. The analysis index used the ratio of net profit to business revenue for profitability, and Subsidies index the ratio of subsidies to business revenue(state subsidies for facility investment purposes, Fund related to essential business, research revenue and contribution revenue). According to the study, the ratio of state subsidies, which are direct subsidies, was very high at 57.30 percent for public institution hospitals. ratio of Fund related to essential business, which is a tax reduction effect with indirect subsidies, had the highest at 6.69 percent for Private University Hospitals. which are Indirect subsidies for deficit or operational assistance, research revenue ratio had the highest 2.8 percent for National University Hospitals, contribution revenue ratio had the highest 36.4 percent for public institutions. As a result of looking at the impact of subsidies on profitability, Nation University Hospitals had the lower the ratio of Fund related to essential business and the ratio of research revenue, the higher the net profit ratio of Business revenue. Medical Corporation Hospitals and Foundation Hospitals had the higher the ratio of Fund related to essential business to business revenues, the higher the net profit ratio of business revenue. These results mean that profitability may fluctuate depending on the utilization of funds related to essential business.

• Journal of the Korea society of information convergence
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• v.7 no.2
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• pp.25-29
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• 2014

In this study, it examined the effects of alcohol on the physiology of the eye and ocular function. It was measured to IOP(intraocular pressure), tear secretion, stereoscopic parallax, AC A ratio, convergence ability, divergence ability alcohol intake before and after. The results were as follows. The mean IOP before alcohol intake 15.14mmHg and the mean IOP after alcohol intake 12.8mmHg. Average decreased 15.44%. The mean tear secretion before alcohol intake 17.125mm and the mean secretion after alcohol intake 9.875mm. Average decreased 42.33%. Stereoscopic parallax has increased by about four times that 40' before alcohol intake to 165' after that. AC/A ratio has increased by 14.6% that $5.40{\Delta}/D$ before alcohol intake to $6.19{\Delta}/D$ after that. Convergence and divergence ability was no significant change in both distance and close range.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.187-195
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• 2005

When a tunnel is excavated below groundwater table, the groundwater flow occurs towards the tunnel resulting in the seepage pressure. In this paper, the effect of groundwater flows on the behavior of shotcrete lining installed between ground-liner interfaces was studied considering permeability ratio between the ground and the shotcrete into account. Three-dimensional coupled finite element analysis was performed for this assessment. Seepage forces will seriously affect the shotcrete behavior since arching phenomena do not occur in seepage forces. A parametric study was conducted on the various tunnelling situations including interfacial properties between ground and shotcrete lining, the shape of tunnel cross-section and the thickness of liner, etc. Moreover, the convergence-confinement method (CCM) of a NATM tunnel considering seepage forces was proposed. The result showed that the more water tight is the shotcrete, the smaller is the convergence and the larger is the internal pressure. Therefore, the watertight fiber-reinforced shotcrete is found to be even more advantageous when used in under water tunnel.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.215-223
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• 2017

This article has tried to analyse the effect of the corporate earning return tax empirically through analysis on the impact of previous internal reservation on the dividends rate of the current year. In addition to this, this article has tried to the effectiveness of government policies with leverage ratio as a moderating variable. Moreover, DRF and GBM model were used to see the effect again. As a result of the actual proof analysis, OCF, ROE, FOR have a significance level of 99% in model1, model2, model3. However, ADV and MSE has appeared not to be meaningful in all models. In the result of DRF and GBM model for convergence was higher than GBM in depth and leaves. However, when it comes to a model explaining capability, GBM high than DRF. The further study will be required to examine the effect of government policy by time series analysis in the period of enforcement of the reflux tax, from 2015 to 2017.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.27-31
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• 2011

ZnS:Mn yellow phosphors doped with Sm for white light emitting diodes were synthesized by solid state reaction method. These sample showed the characteristic X-ray diffraction patterns for main peak (110) of ZnS:Mn,Sm. Photoluminescence excitation spectra originated from $Mn^{2+}$ were ranged from 450 nm to 500 nm. The yellow emission at around 580 nm was associated with $^4T_1{\rightarrow}^6A_1$ transition of $Mn^{2+}$ ions in ZnS:Mn,Sm phosphors. The highest photolum inescence intensity of the phosphors under 405 nm and 450 nm excitation was obtained at Sm concentration of 1 mol%. The enhanced photoluminescent intensity in the ZnS:Mn,Sm phosphors was interpreted by energy transfer from Sm to Mn. The highest luminescent intensity of white LED was obtained at the epoxy-to-yellow phosphor ratio of 1:3. At this ratio, the CIE chromaticity of the white LED was X=0.3886 and Y=0.2928.

• Korean journal of food and cookery science
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• v.28 no.1
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• pp.51-55
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• 2012

This study was conducted to investigate the physicochemical properties of citrus peel extracts with different hot water extraction and enzymatic hydrolysis conditions. Enzymatic hydrolysis was also employed using Viscozyme L and results were compared with that of optimized hot water extract. Hot water extraction was performed under different parameters; the sample to solvent ratio(1:20, 1:15, 1:10), extraction time(2, 4 hrs), extraction temperature(85, $95^{\circ}C$) and enzymatic hydrolysis(0, 1%) and the subsequent extracts were used for determining their physicochemical properties, such as total yield, total phenolics, total flavonoids, and electron donating ability (EDA). With the increase in the sample to solvent ratio and extraction time, total yield, total phenolics, total flavonoids and EDA increased. But extraction temperature did not significantly affect the hot water extract. As hot water extract was hydrolyzed by the enzyme, total yield and active ingredients increased rapidly. In the result of total yield, total phenolics, total flavonoids and EDA, the activity of enzyme-treated extract was higher than those of enzyme-untreated extract. Based upon the overall hot water extraction efficiency, it was found that 20 times volume or 120 min at a time at $95^{\circ}C$ after enzyme treatment was optimal.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.149-157
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• 2018

This study was conducted using the National Health and Nutrition Survey data for 2010-2014 to investigate the relationship between pregnancy-related health factors and periodontitis in adult women. Dependent variable was periodontitis, and independent variables, pregnancy-related health factors(duration of lactation and number of pregnancies) were analyzed. Socioeconomic variables and health-related behaviors were corrected by confounding variables. The number of pregnancies and periodontitis were highly correlated after adjusting for various confounding factors [odds ratio for women with 2-3 pregnancies: 2.66 (95% confidence interval(CI): 1.56-4.54); The odds ratio for women with four or more pregnancies 3.02 (95% CI: 1.70-5.36). In conclusion, periodontitis is closely related to the number of pregnancies and this will be used as basic data for development of oral health education programs for women and pregnant women.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.569-573
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• 2014

We demonstrate a low-cost, superbly efficient way of etching for the nano-, and micro-sized pyramid patterns on (100)-oriented Si wafer surfaces for use as a patterned master. We show a way of producing functional optical films for the viewing angle direction brightness-enhancement of Lambertian LED (light emitting diode)/OLED (organic light emitting diode) planar lighting applications. An optimally formulated KOH (Potassium hydroxide) wet etching process enabled random-positioned, and random size-distributed (within a certain size range) pyramid patterns to be developed over the entire (100) silicon wafer substrates up to 8" and a simple replication process of master patterns onto the PC (poly-carbonate) and PMMA (poly-methyl methacrylate) films were performed. Haze ratio values were measured for several film samples exhibiting excellent values over 90% suitable for LED/OLED lighting purposes. Brightness was also improved by 13~14% toward the viewing angle direction. Computational simulations using LightTools$^{TM}$ were also carried out and turned out to be in strong agreement with experimental data. Finally, we could check the feasibility of fabricating low-cost, large area, high performance optical films for commercialization.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.67-73
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• 2019

An ultra-high pressure treatment device is a device used for increasing the shelf life of food by sterilizing it by applying hydrostatic pressure to solid or liquid food. The ultrahigh pressure treatment system developed in this study is a pressure vessel with a processing capacity of 100 L and a maximum pressure of 700 MPa. Pressure vessels for ultrahigh-pressure processing equipment are manufactured using wire-winding techniques. The design formula for making ultra-high pressure vessels with wire windings is given in ASME Section VIII - Division 3. In this study, the ratio of the cylinder to the winding area that can be applied in a wire-winding application was analyzed using a finite element analysis. Furthermore, the relationship between the variation of the residual stress in the vessel and the ratio of the winding area due to the variation of the winding tension was analyzed, and a design guide applicable to the actual product design was developed. Finally, the design equation was modified by presenting the coefficients to correct the difference between the finite element analysis and the design equation.