• Journal of Korea Technology Innovation Society
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• v.5 no.2
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• pp.129-140
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• 2002

This study is try to do the empirical tests on the relationship among innovation cycle, investment cycle, and business cycle suggested in recent economic growth models. We apply co-spectra analysis to estimate dynamic correlations in the extraction HP filtered variables and first difference filtered variables in our data set. Our empirical results are; (i) an existing asynchronization between innovation cycle and investment cycle, (ii) in the long frequency, an existing positive correlation between innovation cycle and business cycle, (iii) in the short frequency, however, a finding the high negative correlation between the two cycle. Our empirical findings support the recent growth through cycle models and suggest some economic policy implementations for economic stabilization during a severe business cycle.

• Fire Science and Engineering
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• v.18 no.3
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• pp.9-17
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• 2004

The values of physical properties of the inert gases of Ar, $N_2$, $CO_2$ were calculated by the empirical equations. The regression coefficients were obtained by the experimental data and the resulting calculated values. For the empirical equation with a lower regression coefficient, a new correlation was suggested. At an atmosphere pressure, the empirical equation was confirmed by the experimental values for the viscosity, density, saturated pressure, and surface tension of Ar, $N_2$, $CO_2$. The correlation coefficients of the empirical equations proposed in this work was higher than 0.99.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.27-35
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• 2018

The passive containment cooling system (PCCS) has been designed to remove the released decay heat during the accident by means of the condensation heat transfer phenomenon to guarantee the safety of the nuclear power plant. The heat removal performance of the PCCS is mainly governed by the condensation heat transfer of the steam-air mixture. In this study, the heat removal performance of the PCCS was evaluated by using the MARS-KS code with a new empirical correlation for steam condensation in the presence of a noncondensable gas. A new empirical correlation implemented into the MARS-KS code was developed as a function of parameters that affect the condensation heat transfer coefficient, such as the pressure, the wall subcooling, the noncondensable gas mass fraction and the aspect ratio of the condenser tube. The empirical correlation was applied to the MARS-KS code to replace the default Colburn-Hougen model. The various thermal-hydraulic parameters during the operation of the PCCS follonwing a large-break loss-of-coolant-accident were analyzed. The transient pressure behavior inside the containment from the MARS-KS with the empirical correlation was compared with calculated with the Colburn-Hougen model.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.108-118
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• 1994

A semi-empirical correlation has been developed for adiabatic interfacial friction factors in a long horizontal air-water countercurrent stratified flow conditions. Using a pipe and duct test sections, a series of experiments hate been conducted varying non-dimensional water depth and flow rates of air. On the basis of simultaneous measurement of the main flow parameters in a horizontal pipe and a duct, a semi-empirical correlation for the interfacial friction factor in a stratified flow regime has been developed employing a new concept of surface roughness in wavy flow. A total of 201 data point, including 15 concurrent pipe flow test data of others, have been used in the present analysis. A comparison between the data and the predictions of the present correlation shows that the agreement is within $\pm$30%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.8
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• pp.527-533
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• 2016

A new empirical correlation was developed to identify the effect of an inclination angle on pool boiling heat transfer coefficient of a tube submerged in the saturated water at atmospheric pressure. Through the experiments and the survey of published results 431 data points were obtained and the nonlinear least square method was used as a regression technique. The heat flux of the tube($0{\sim}120kW/m^2$), inclination angle($0^{\circ}{\sim}90^{\circ}$), and the length divided by the diameter of a tube(18~42.52) were selected as major parameters. The newly developed correlation well predicts the experimental data within ${\pm}18%$, with some exceptions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.11
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• pp.881-887
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• 2006

The objective of this study are to analyze the flow characteristics of R22 flowing through EEVs and to develop an empirical correlation to predict the refrigerant flow rate. The mass flow rates of EEVs with different geometries were measured at various condensing temperatures, subcoolings, and EEV openings. Based on the experimental data, an empirical correlation for mass flow predictions in EEVs was developed by modifying the orifice equation. The correlation showed good agreement with the measured data for R22 with average and standard deviations of 1.4% and 6.1%, respectively. Approximately 90% of the measured data were within ${\pm}10%$ of the predictions.

• 한국가시화정보학회:학술대회논문집
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• 2003.11a
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• pp.111-114
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• 2003

Drop size is one of the most important parameters which are control the performance of the engine using liquid fuel/oxidizer and drop formation is mainly controlled by aerodynamic force caused by ambient gas. Because of this, empirical data and correlation acquired under standard ambient condition are not valid. So experiments under high ambient pressure condition to measure the drop size using image processing method And find the empirical correlation between SMD and chamber pressure(density), injection velocity.

• Journal of the Korean Statistical Society
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• v.32 no.2
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• pp.175-191
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• 2003

An empirical Bayesian approach is discussed for estimation of characteristics from the two-way balanced rotation sampling design which includes U.S. Current Population Survey and Canadian Labor Force Survey as special cases. An empirical Bayesian estimator is derived for monthly effect under presence of two types of biases and correlations It is shown that the marginal distribution of observation provides more general correlation structure than that frequentist has assumed. Consistent estimators are derived for hyper-parameters in Normal priors.

• Journal of Environmental Science International
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• v.21 no.5
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• pp.613-622
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• 2012

A pilot-scale pulse-jet bagfilter was designed, built and tested for the effects of four operating conditions (filtration velocity, inlet dust concentration, pulse pressure, and pulse interval time) on the total system pressure drop, using coke dust from a steel mill factory. Two models were used to predict the total pressure drop according to the operating conditions. These model parameters were estimated from the 180 experimental data points. The empirical model (EM) with filtration velocity, areal density, inlet dust concentration, pulse interval time and pulse pressure shows the best correlation coefficient (R=0.971) between experimental data and model predictions. The empirical model was used as it showed higher correlation coefficient (R=0.971) compared to that of the Multivariate linear regression(MLR) (R=0.961). The minimum pulse pressure predicted by empirical model (EM) was 5kg/$cm^2$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.1
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• pp.1-8
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• 2017

A new empirical correlation was developed for application to the tandem tubes for saturated water at atmospheric pressure. The correlation was obtained by using experimental data and the least square method to calculate the bundle effect. A statistical analysis was performed to identify the suitability of the correlation. The correlation predicted the experimental data within ${\pm}8%$. The applicable ranges of the correlation correspond to a tube pitch of 28.5~114 mm, an elevation angle of $0^{\circ}{\sim}90^{\circ}$, an inclination angle of $0^{\circ}{\sim}90^{\circ}$, and heat fluxes of $0{\sim}120kW/m^2$ of the lower and upper tubes.