• Korean Journal of Environment and Ecology
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• v.15 no.3
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• pp.257-266
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• 2001

Trail might be the primary recreational space to appear the use impact by visitors on ecological space in National park. On the basis of this concept, the carrying capacity was estimated on the trail. Impact rating class and pattern of passersby were surveyed on the 22 valid trails in Bukhansan National Park. Using two variables, the width of trail and amount of passersby, the correlation coefficient was analysed and the regression model was derived by raising x to a higher power. And carrying capacity estimation equation was devised by considering the pay fee visitors and average passersby in a trail section. With carrying capacity estimation equation to apply Bukansan National Park, it is desired that maximum carrying capacity is about 3 million persons a year under conditions of trail width 2.2m when National Park Authority wants to keep the existing management level. If they strengthen the management goal far resource conservation like that they want to keep the trail width 2.0m, the number of visitors might be decreased to about 2 million persons a year.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.43-49
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• 2012

This study was conducted to develop a stem volume table for the Robinia pseudoacacia using stem taper equations. Specifically, Kozak's model was used in the estimation of each model parameter. The fitness of the estimated model was statistically verified and results of the residual analysis were found significant. Therefore, this model is considered applicable in the preparation of stem volume table for R. pseudoacacia. Furthermore, volume with bark and without bark table were developed based on the bark thickness estimation equation. The bark thickness estimation equation was also statistically significant, The stem volume table developed for R. pseudoacacia, which was first in Korea, is vital in managing these forests.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.37-42
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• 2007

Flash points for the flammable binary systems, n-propanol+acetic acid and n-propanol+n-propionic acid, were measured by Cleveland open cup tester. The Raoult's law, the van Laar equation and the UNIQUAC equation were used for predicting flash points and were compared with experimentally-derived data. The calculated values based on the van Laar and UNIQUAC equations were found to be better than those based on the Raoult's law. And the predictive curve of the flash point prediction model based on the UNIQUAC equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the the van Laar equation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.2189-2205
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• 1991

Thermodynamic properties of binary nonazeotropic refrigerant mixtures are estimated by using a modified Carnhan-Starling equation of state. In this study, pure component refrigerants such as R14, R23, R13, R13 B1, R22, R12, R134a, R152a, R142b, RC318, R114, R11, R123 and R113 are chosen and the thermodynamic properties of enthalpy and entropy are calculated in terms of relevant variables. The modified Carnahan-Starling equation of state is compared with the carnahan-Staring-De Santis equation of sate. Results show that the relative errors become slightly smaller with the equation of state proposed in this study. Correlations are obtained for the mixtures of which the vapor liquid equilibruim data are available to us in the literature. Those mixtures are R14/R23, R23/R12, R13/R12, R13/R11, R13B1/R22, R13B1/RC318, R12/RC138, R12/R114 and R12/R11. The binary interaction coefficients are found under the condition of minimizing the pressure deviations at the vapor liquid equiblibrium state and the estimation of the vapor liquid equilibrium for the refrigerant mixtures is done. Pressure-enthalpy and temperature-entropy diagrams are plotted for the refrigerant mixtures of specific composition.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.614-623
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• 2016

Grid(pipe network) design is an important element of Smart Water Grid, which essential to estimate hydraulic parameters such as the pressure, friction factor, friction velocity, head loss and energy slope. Especially, friction velocity in a grid is an important factor in conjunction with energy gradient, friction coefficient, pressure and head loss. However, accurate estimation friction head loss, friction velocity and friction factor are very difficult. The empirical friction factor is still estimated by using theory and equation which were developed one hundred years ago. Therefore, in this paper, new equation from maximum velocity and friction velocity is developed by using integration relationship between Darcy-Weisbach's friction head loss equation and Schlichting equation and regression analysis. To prove the developed equation, smooth pipe data areis used. Proposed equation shows high accuracy compared to observed data. Study results are expected to be used in stability improvements and design in a grid.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.16-23
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• 2012

BACKGROUND: To improve the Daechung reservoir water quality, a quantitative estimation of the delivery load from upper watershed need to be conducted prior to others. To do so, an intensive monitoring is necessary because of the complexity and uncertainty of the delivery load from uppper watershed. However, intensive monitoring need to invest much time, cost, and effort. So, many researcher have developed an equation to estimate the delivery loads. But, relatively little research has been conducted on the applicability of pre-developed equation using other sites. Therefore, the objective of this study was to evaluate application of the equation for BOD, T-N and T-P delivery load. METHODS AND RESULTS: To verify the applicability of the equation, the following equation was used; Delivery loads(kg/day)=generated pollutant loads${\times}(1-{\alpha}){\times}$(daily outflow/${\beta})^{\gamma}$. The equations could be calculated the daily delivery loads of streams without any data of water quality, only with the data of daily runoff of study sites. The equations were applied to Youngdogcheon, Chogangcheon, Bocheongcheon, Sookcheon to examine its applicability using monitoring data. The results showed that the estimated delivery loads were in a good agreement with the observed data and indicated reasonable applicability of the equations. CONCLUSION(s): Overall, the equations were satisfactory in estimation of delivery loads at upper watershed of the Daechung reservoir. Therefore, the equations could be contributed to better water quality management in the Daechung reservoir.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.185-193
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• 2012

In this study, an estimation equation was proposed to predict the shear strength of RC interior beam-column connections. The proposed equation considered the effect of both truss and arch mechanisms, while the existing equations in the ACI and AIJ design codes consider only arch mechanism. In addition, the proposed equation estimates the shear strength of RC joints by considering the contribution of the vertical and horizontal steel bars on the effective compressive strength of concrete. The shear strength of RC joints calculated by the proposed equation was compared with the test results of 54 RC joints, which failed in shear before plastic hinges developed at the end of the adjacent beams. The comparison study showed that the proposed equation estimated the strength of the 54 specimens with a mean value of 1.14 and the coefficient of variation of 20%. The proposed equation provides improved prediction compared to those obtained from the equations in the ACI and AIJ design codes.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.50-57
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• 2005

Ice resistance on ice-transiting vessels is one of th￡ important issues concerning th￡ design of ships with ice classes. In this study, th￡ development of GUI software for estimation of ice resistance on ice-transiting vessels is discussed. lee resistance estimation equations, based on model tests and full-scale sea trial data from many previous research articles, are studied in conjunction with two ship categories i.e., ,icebreakers/supply/tug vessels and ice-strengthened cargo vessels. lee resistance estimation equations are summarized in common format and are compared with each other. The GUI software 'Ice View,' written in MS Visual Basic language, can calculate ice resistances according to varying ice thickness and ship speed. The software can provide the calculated results, with suitable tables and graphs, for easy comparison of each ice resistance estimation equation.

• 한국데이터정보과학회:학술대회논문집
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• 2006.04a
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• pp.163-169
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• 2006

This paper deals with the comparison of parameter estimation methods in a 3-parameter Kappa distribution which is sometimes used in flood frequency analysis. The method of moment estimation(MME), L-moment estimation(L-ME), and maximum likelihood estimation(MLE) are applied to estimate three parameters. The performance of these methods are compared by Monte-carlo simulations. Especially for computing MME and L-ME, ike dimensional nonlinear equations are simplied to one dimensional equation which is calculated by the Newton-Raphson iteration under constraint. Based on the criterion of the mean squared error, the L-ME is recommended to use for small sample size $(n\leq100)$ while MLE is good for large sample size.

• Journal of Ship and Ocean Technology
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• v.3 no.3
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• pp.25-44
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• 1999

Estimation efficiencies according to different sea trial are investigated in connection with sensitivity analysis, and new trial method is proposed which can improve the estimation efficiency of hydrodynamic derivatives. MMG Equation with Kijima's formula is used for simulation. Extended Kalman Filter is chosen for estimation technique and hydrodynamic derivatives of interest is limited to 12 of those in sway and yaw equations. Esso Osaka is selected for the test ship. Sensitivity analysis and estimation results based on conventional trials show that a more sensitive derivative gives more efficient estimation result. Sensitivities of nonlinear derivatives become pronounced in the trial where steady condition lasts longer such as turning test, while sensitivities of linear derivatives gas a larger values in the trial where unsteady condition lasts longer such as 10deg-10deg zigzag test. Consequently, in new method , named S-type trial, steady and unsteady condition are combined appropriately to increase sensitivities. Linear derivatives are estimated better in S-type trial and the estimation of nonlinear derivatives is improved to extent.