• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.123-132
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• 2016

We can achieve the principle of parsimony and efficiency if homogeneity for panel time series model is satisfied. We suggest a Rao test statistic and a Wald test statistic for the test of homogeneity for panel AR(1) and derived the limit distribution. We performed a simulation to examine statistics with the same chisquare distribution when number of the individual is small and in common with large. We also simulated to compare the empirical power of the statistics in a small panel. In application, we fit panel AR(1) model using regional monthly economical active population data and test homogeneity for panel AR(1). It is satisfied homogeneity, so it could be fitted AR(1) using the sample mean at the time point. We also compare the power of prediction between each individual and pooled model.

• Journal of Korean Medical classics
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• v.23 no.2
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• pp.63-87
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• 2010

Natural Medicine is a medical system that tries to find the cause and cure of the disease in the nature emphasizing on natural healing power of human body. The most important value of traditional medicine in east Asia lies on the fact that this medicine is a medical culture and natural medicine that was selected by instinct and human nature reflecting the best possible remedy by the wisdom of evolution, and views the living phenomenon based on relation and circulation. This medicine is a natural medicine that tries to recover and promote the natural healing power by vitality and is a system that cumulates various empirical information about unique and complicated life phenomenon as a legacy of evolution in the body and the disease. The understanding of variation and adaptation of human species should be based on thorough knowledge of origin, instinct and nature of human as well as knowledge of survival and adaptation of human and environment based on evolution. And through this insight, the prevention and treatment of modern diseases should be developed. In this regards, traditional medicine in east Asia should be highlighted again as a study on adaptation and harmony of penetrating the cultural history of mind which has led the history of biological body and change of society and culture, and the repository of practical wisdom and knowledge.

• Journal of Distribution Research
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• v.10 no.4
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• pp.41-67
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• 2005

At this paper, we investigate two factors of market aspects, such as market power perspective and market efficiency perspective, as influential factors on size of slotting allowances of new products. Also, our research might examine the effects of slotting allowances of new products on both performance of new products and consumer prices. For the empirical research, we analysis 128 domestic manufacturers. In result, there is a positive relationship between retailers' brand equity and the size of slotting allowances. However, there is a negative relationship between retailer replaceability and the size of slotting allowances. Also, the effect of transaction period is negative direction and the effect of the environment uncertainty is positive direction. And the effect of the scale of the slotting allowance of new products is positive direction on the performance of the manufacturers and the price of new products. And, the theoretical and practical implications of this result and future research were suggested.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.3
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• pp.55-62
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• 2000

This paper presents an analysis of the chaotic behavior in the discrete-time voltage mode chaotic generator fabricated using 0.8${\mu}{\textrm}{m}$ single poly CMOS technology. An approximated empirical equation is extracted from the measurement data of a nonlinear function block. Then the bifurcation diagram is simulated according to input variables and Lyapunov exponent λ which represent a dependence on an initial value is calculated. We show the interrelations among time waveforms, state transition, and power spectra for the state condition of chaotic circuit, such as equilibrium, periodic, and chaotic state. And results of experiments in the chaotic circuit with the $\pm$2.5V power supply and sampling clock frequency of 10KHz are shown and compared with the simulated results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.8
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• pp.408-418
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• 2017

Supercritical carbon dioxide ($sCO_2$) power system is emerging technology because of its high cycle efficiency and compactness. Meanwhile, PCHE (Printed Circuit Heat Exchanger) is gaining attention in $sCO_2$ power system technology because PCHE with high pressure-resistance and larger heat transfer surface per unit volume is fundamentally needed. Thermo-fluidic characteristics of $sCO_2$ in the micro channel of PCHE should be investigated. In this study, heat transfer characteristics of $sCO_2$ of various inlet conditions and cross-sectional shapes of single micro channel were investigated experimentally. Experiment was conducted at supercritical state of higher than critical temperature and pressure. Test sections were made of copper and hydraulic diameter was 1 mm. Convective heat transfer coefficients were measured according to each interval of the channel and pressure drop was also measured. Convective heat transfer coefficients from experimental data were compared with existing correlation. In this study, using measured data, a new empirical correlation to predict near critical region heat transfer coefficient is developed and suggested. Test results of single channel will be used for design of PCHE.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.153-163
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• 2016

Environments in nuclear power plants (NPPs) are changing as the design of instrumentation and control systems for NPPs is rapidly moving toward fully digital instrumentation and control, and modern computer techniques are gradually introduced into main control rooms (MCRs). Within the context of these environmental changes, the level of performance of operators in a digital MCR is a major concern. Situation awareness (SA), which is used within human factors research to explain to what extent operators of safety-critical systems know what is transpiring in the system and the environment, is considered a prerequisite factor to guarantee the safe operation of NPPs. However, the safe operation of NPPs can be guaranteed through a team effort. In this regard, the operating team's SA in a conventional and digital MCR should be measured in order to assess whether the new design features implemented in a digital MCR affect this parameter. This paper explains the team SA measurement method used in this study and the results of applying this measurement method to operating teams in different MCR environments. The paper also discusses several empirical lessons learned from the results.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.4
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• pp.1-7
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• 2003

This study is concerned with the operational methods of Quality Management employed by the small and medium-sized companies in Gang won-do to improve their power of competition. This study is particular, studied the consortium-participating companies on their Plans of Quality Management as to how they carry them out in order to advance to the first-class business enterprises. The results of this study showed that the of shortage manpower and funds that the local small and mediumsized companies commonly face played a significant role as major obstacles in implementing their Quality Management programs. The study results also suggest that it is necessary to promote some periodic manpower train- ing programs in cooperation with local universities, to utilize professors and experts to build management strategies that can bring and secure the power of competition, and to construct a system of educational-industrial cooperation, as ways leading these companies to the 21s1 century's type of business enterprise.

• Journal of Korea Technology Innovation Society
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• v.9 no.4
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• pp.812-841
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• 2006

Previous studies have shown that the ex-ante financial ratios, mainly used by financial institutions for loan evaluation purpose, are related to the ex-post finn's performance of venture firm's. The main objective of this study is to examine whether non-financial variables such as 'technology', 'marketability', and 'other business indexes' have extra explanatory power in forecasting the ex-post firm's performance of small and medium size venture firm's in Korea. The implications and results of this study are expected to be useful in loan evaluation, investment decision and internal management decisions of venture firms. Among small and medium sized manufacturing firms funded in the year of 1999 through 2005, 416 firms are selected for our analysis. The relationship between evaluation indexes and firm's success/failure is investigated using binary logistic regression analysis and factor analysis with an aid of SPSS program. The summarized results are as follows. First, current evaluation model, used for loan evaluation purpose for small and medium size manufacturing firms show the same discriminatory power as previous prediction model. Second, among the tested additional variables, significant indices are 'technological capability of CEO', 'managerial capability of CEO', and 'business feasibility'. Third, while previous studies on evaluation structure had 3 factors, this study showed that valuation's structure has 6 factors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1171-1179
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• 2013

Recently there is show deep concern at the wellness of health and beauty. therefore this study is to investigate an empirical study on the relational characteristics and collaboration between wholesalers and oriental clinic in herb medicine supplier channel, specially focused on lycium chinense. We collected statistically usable data from 119 questionnaire respondents who live in national provinces and analyzed them with SPSS 20.0 to achieve research's goals. Analysis results revealed that, first, relational characteristics of relationalism, trust, reward power and dependence had impacts on satisfaction between wholesaler and oriental clinic in herb medicine, Second, the survey found that satisfaction has impact on collaboration. Third, this study partially supported mediating effect regarding satisfaction between relational characteristics of relationalism and reward power.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.210-216
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• 1990

This study was performed to obtain fundamental data on temperature increases in the dental tissues irradiated by IO.opm laser radiation. For this purpose a experimental facility was established. which was composed of a CO2 laser. a shutter unit and a temperature sensing device. The temperature changes in the pulp chamber of extracted molars. during and after the laser irradiation. were measured as function of laser power. the time of irradration and the thickness of the sample. An empirical formula for the maximum temperature increases, $\DeltaT_m$ was derived from the measured data as follows; $\DeltaT_m=\alphaP\Delta\tauexp(-\betad)$$ where P. $\Delta\tau$ and d are the laser power(W). irradiation time{sec) and the thickness(mm) between pulp chamber and occlusal surface. respectively. Also a theoretical calculation model based on simplified assumptions were established and the results from the calculation were compared with the measured temperature data. A fairly good agreement was obtained.obtained.