• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.101-114
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• 1995

In this paper we consider the multiple unit root tests both for the regular and seasonal unit roots based on the Lagrange Multiplier(LM) principle. Unlike Li(1991)'s method, by plugging the restricted maximum likelihood estimates of the nuisance parameters in the model, we propose a Lagrange multiplier test which does not depend on the existence of the nuisance parameters. The asymptotic distribution of the proposed statistic is derived and empirical percentiles of the test statistic for selected seasonal periods are provided. The power and size of the test statistic for examined for finite samples through a Monte Carlo simularion.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.199-202
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• 2004

In this present study, an attempt was made to determine the deformation mode of the Zr-Ti-Cu-Ni-Be bulk metallic glass by compression test over a wide range of temperatures and strain rates. From the results, empirical deformation map could be constructed including the boundaries of different deformation modes. Considering power dissipation map and instability map developed on the basis of the Dynamic Materials Model (DMM), the processing map for extrusion could also be constructed. In addition, the macroscopic formability of this BMG alloy has also been examined through the extrusion in laboratory scale within undercooled liquid state. From the results of macroscopic extrusion formability, both deformation map and processing map present good criteria to determine optimal forming conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.519-524
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• 2011

The aim of this study is to develop an automated program for noise prediction in shipboard compartments, for this purpose of calculating noise levels accurately and quickly. The program calculates sound power level at HVAC components based on the empirical method suggested by NEBB and utilizing the manufacturer's test data. The program developed uses the GUI functions to help in efficient modeling and calculation. To verify the reliability of developed program, the predicted data was compared with the measured data in shipboard compartments. As a result, the average difference between predicted and measured data is ${\pm}3dB$.

• 소음진동
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• 제9권6호
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• pp.1116-1122
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• 1999

HRSG, which is one of main components of the combined cycle power plant,is composed of an inlet duct, a main body and casing, an outlet duct and a stack. It is important to design HRSG wihtin the allowable noise limit. For this purpose, it is necessary to analyze and predict the noise reduction and radiation at HRSG. In this paper, the technology for the noise prediction at each part of HRSG has been based on the empirical and field data, and also the HRSG noise prediction program has been developed. In order to verify the developed technology and program a field test is conducted. The results of noise prediction show good agreement with the measured.

• Communications for Statistical Applications and Methods
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• 제4권3호
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• pp.663-676
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• 1997

We obtain the simultaneous unit roots test statistics for both regular and seasonal unit roots in a time series with possible seasonal deterministic trends. The limiting distributions of the proposed test statistics are derived and empirical percentiles of the test statistics are tabulated for some seasonal periods. The power and size of the test statistics are examined for finite samples through a Monte Carlo simulation and Compared with those of the Lagrange multiplier test.

• 오토저널
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• 제10권6호
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• pp.25-38
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• 1988

As a mean of increasing engine power, great attention has been concentrated on the turbo-charging owing to better fuel economy, smaller engine size and lower emission. The performance in turbocharged engine depends not only on the efficiency of the engine and the turbocharger used, but also on the total characteristics of the system by the matching turbocharger to the engine. The matching of the turbocharger to the engine has been usually accomplished by the empirical techniques with a great deal of laborious work. It would be better to predict the performance and emission in the turbocharged engine using the effective simulation model. In this study, computer simulation program has been developed to predict the transient variation of properties of gas in the cylinder, intake and exhaust pipes, the engine performances and emissions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1770-1772
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• 1997

In this paper, Voltage-time characteristics of lightning impulse and switching surge breakdown in SF6 is studied on the gap and various pressure. The characteristics is categorized into three pattern depending on the configuration of the gap and gas pressure. The properties of the voltage-time characteristics in these patterns are generalized as semi-empirical formula which will be useful in the quantitation voltage evaluation of insulation coordination and the abnormal voltage protection of SF6 insulated power equipment.

• 한국경영과학회지
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• 제31권2호
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• pp.41-55
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• 2006

RFID (Radio Frequency IDentification) is a wireless frequency recognition technology that can be used to recognize, trace, and Identify people, things and animals using radio frequency. Although current RFID technology can provide wide advantages in many fields, most companies do not consider widely adopting this technology yet. This paper presents RFID implementation as a technology innovation. This research selects three affecting factors of IT infrastructure, fitness of Tag, fitness of Frequency, and one moderator of the power of business partners, on RFID adoption based on innovation model, and then empirical survey is conducted among the companies using RFID technology or planing for RFID adoption to investigate the relationship of three affacting factors and one moderator factor. Reserachers can find the direction to activate RFID technology as a competitive advantage.

• Environmental Engineering Research
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• 제21권1호
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• pp.74-83
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• 2016

The purpose of this study is to identify the driven factors affecting the changes in energy-related $CO_2$ emissions in Hebei Province of China from 1995 to 2013. This study confirmed that energy-related $CO_2$ emissions are correlated with the population, urbanization level, economic development degree, industry structure, foreign trade degree, technology level and energy proportion through an improved STIRPAT model. A reasonable and more reliable outcome of STIRPAT model can be obtained with the introducing of the Ridge Regression, which shows that population is the most important factor for $CO_2$ emissions in Hebei with the coefficient 2.4528. Rely on these discussions about affect abilities of each driven factors, we conclude several proposals to arrive targets for reductions in Hebei's energy-related $CO_2$ emissions. The method improved and relative policy advance improved pointing at empirical results also can be applied by other province to make study about driven factors of the growth of carbon emissions.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.19-22
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• 2003

For CHNO explosives, two new correlations of the form $P_{CJ}\;=\;8.7({\alpha}T_c')^{1/2}{\rho}_0^2-5\;and\;P_{CJ}\'=\'9.5({\alpha}T_c')^1/2{\rho}_0^2-9$ have been demonstrated, which relate detonation pressure, $P_{CJ}$; combustion temperature of the explosive in gas phase, $T_c$; combustion temperature of the explosive in crystalline state, $T_c'$; and the number of moles of gaseous products per unit weight of explosive, α; at initial density of the explosive, ${\rho}_0$. Experimental and semi-empirical PM3 procedures were used for the computation of $T_c$. Detonation pressures derived in this manner have a simple form without need to use computer code.