• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.229-238
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• 2017

This study started to deduce a permeability relationship that can consider the geometric features of various porous media under different flow regimes. With reference to the previous works of Kozeny and Carman, the conventional Darcy-Weisbach relation (Darcy's friction flow equation) was reviewed and expanded for porous flow analysis. Based on the capillary model, this relation was transformed to the friction equivalent permeability (FEP) definition. The validity of the FEP definition was confirmed by means of comparison with the Kozeny-Carman equation. Hereby, it was shown that the FEP definition is the generalized form of the Kozeny-Carman equation, which is confined to laminar flow through a circular capillary. In conclusion, the FEP definition as a new permeability estimation method was successfully developed by expanding the Darcy-Weisbach relation for porous flow analyses.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.3
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• pp.13-26
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• 2010

Objectives : This study was to investigate the effects of Imyo-san treatment on the monosodium iodoacetate-induced osteoarthritis in rats. Methods : Arthritis was induced by injection of monosodium iodoacetate(MIA)(0.5 mg) into both knee joint cavities of rats. Arthritic rats were divided into control(n=8) and treated(n=8) group. Control group was taken distilled water and treated group was taken extracts of Imyo-san by orally for 20 days. At the end of experiment(20day after MIA injection), gross and histopathological examination on the articular structures of knee joints were performed. Blood cell counts and proteoglycan(PG) contents in articular cartilages were analysed. And also, tumor necrosis factor-$\alpha$($TNF-{\alpha}$) and interleukin-$1{\beta}$($IL-1{\beta}$) contents synovial fluids were measured by enzyme-liked immunosorbent assay(ELISA) method. Results : 1. Body weight(g) of the treated group were increased significantly compared with control group at 15 and 20 days after injection. 2. Grossly, degree of osteoarthritis in the treated group was alleviated compared with the control group. 3. PG content in articular cartilage of the treated group was increased significantly compared with the control group. 4. Histopathologically, osteoarthritic scores of the treated group was decreased significantly compared with the control group. 5. $TNF-{\alpha}$ content in synovial fluid of the treated group was decreased significantly compared with the control group. Conclusions : On the basis of these results, we suggested that Imyo-san has inhibiting effects on the progression of arthritis in MIA-induced osteoarthritis model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1032-1038
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• 2017

Recently, regulation on carbon emissions has been strengthened according to the new climate change convention (COP21) held in Paris, and then Korea has decided to reduce CO2 emissions by 37% until 2030. As one of countermeasures, the government has energetically performed demonstration projects of island micro-grid including solar power, wind power and energy storage system. However, in order to smoothly introduce island micro-grid, it is a critical issue to carry out the economic evaluation for power utility aspect and independent power producer aspect. Therefore, this paper proposes economic evaluation algorithms of island micro-grid which are based on the present worth method, considering cost and benefit factors in the aspect of both sides. Firstly, in case of power utility this paper proposes algorithm to estimate a period of return on investment according to the introduction capacity of distributed generators replacing diesel generator. And also, in case of independent power producer, this paper proposes evaluation algorithm to estimate weighting factor of SMP and benefit rate based on break-even point related with cost and benefit. From a case study result on real island micro-grid model, it is confirmed that proposed algorithms are useful and practical for the economic evaluation of island micro-grid.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.99-116
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• 2015

The concept of Cloud computing has been introduced in the IT field over 10 years and industry has been expanding constantly. However, compare to the maturity of global market, Korea cloud computing industry is only in the early stage. Even the Korea has advantages in technology infrastructure; the pace of Korea cloud computing market growth is taking a serious downturn. Under these circumstances, it is needed to be discussing that strategy for expanding the cloud computing market size and for sustaining global competitiveness of local companies. Previous studies on plans for Korea cloud computing market has been conducted since 2009 and most of them are tend to examined in demand perspective. Thus, this study aims at identifying the priority of business challenges for making better performance in the market with service provider aspects. To analyze the important factors in the providing cloud computing service, ANP methodology was applied in this study. The network model including five clusters, security, stability, performance, consumer, and institution, was defined through literature review and expert survey was conducted to collect data. As a result of ANP analysis, 'Securing service reliability' was analyzed as the most important factor and followed by 'Preparing the range of legal liability', 'Preventing personal information leakage' and 'Preventing confidential information data leakage.' The priority of result indicates that service provider needs to focus on to make the secured service environment. This study has significance on analyzing the priority of business challenges in the service provider perspective. This study will provide useful guidelines to for establishing strategies in cloud computing market.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.181-190
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• 2005

The development of web-based distance education surroundings is steadily achieving. However the studying on the learning effect of learners is still weak against development of educational media itself. At present, most of the distance education system is showing limits in the evaluation of the learning effect because the teaming evaluation depends on mid or final-term exams by on-line or off-line. There is a strong point that the distance education is free from space and time. One of present weak points is limitation of evaluating learner's attitude which can estimate learning effects. Earnest teaming attitude at distance education is important factor for improving the learning effects. In this paper, we propose a model for improving the teaming effects by forcing real-time evaluation and returning feedback to learners at the cyber lectures. The developed experimental system is verified its possibilities.

• Environmental and Resource Economics Review
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• v.28 no.4
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• pp.583-615
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• 2019

This paper investigates the level of decoupling between greenhouse gas emissions and economic growth in Korea. Despite previous studies mainly stressed the existence of the Environmental Kuznets Curve, the lack of investigations in the level of decoupling constraints further policy suggestions. This study analyzes the level of decoupling in the short- and long-term, focusing on short-term volatility of GHG emissions income elasticity. In the long run, there is no decoupling in Korea because a robust causal relationship exists between GHGs, GDP, and fossil fuels. However, the short-term volatility is clearly identified under the long-term equilibrium(coupling), indicating there is the relative decoupling in the short run. The results show that fossil fuel dependence is a significant factor that increases short-term volatility(decoupling) and breaks the causal link(coupling) between GHGs and GDP.

• Journal of Engineering Education Research
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• v.13 no.4
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• pp.51-59
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• 2010

In order to manage the lectures efficiently in the university and improve the educational outcome, the process is needed that make diagnosis of the present educational outcome of each classes on a lecture and find factors of educational outcome. In most studies for finding the factors of the efficient lecture, statistical methods such as association analysis, regression analysis are used usually, and recently decision tree analysis is employed, too. The decision tree analysis have the merits that is easy to understand a result model, and to be easy to apply for the decision making, but have the weaknesses that is not strong for characteristic of input data such as multicollinearity. This paper indicates the weaknesses of decision tree analysis, and suggests the experimental solution using multiple decision tree algorithm to supplement these problems. The experimental result shows that the suggested method is more effective in finding the reliable factors of the educational outcome.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.216-221
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• 1999

A mental task combined with noise background is an effective model of laboratory stress for study of psychophysiology of the autonomic nervous system (ANS). The intensity of the background noise significantly affects both a subjective evaluation of experienced stress level during test and the physiological responses associated with mental load in noisy environments. Providing tests of similar difficulties we manipulated the background noise intensity as a main factor influencing a psychophysiological outcome and the analyzed reactivity along withe the noise intensity dimension. The goal of this study was to identify the patterns of ANS responses and the relevant subjective stress scores during performance of word recognition tasks on the background of white noise (WN) of the different intensities (55, 70 and 85 dB). Subjects were 27 college students (19-24 years old). BIOPAC, Grass Neurodata System and AcqKnowlwdge 3.5 software were used to record ECG, PPG, SCL, skin temperature, and respiration. Experimental manipulations were effective in producing subjective and physiological responses usually associated with stress. The results suggested that the following potential autonomic mechanisms might be involved in the mediation of the observed physiological responses: A sympathetic activation with parasympathetic withdrawal during mild 55 and 70dB noise (featured by similar profiles) and simultaneous activation of sympathetic and parasympathetic systems during intense 85dB WN. The parasympathetic activation in this case might be a compensatory effect directed to prevent sympathetic domination and to maintain optimal arousal state for the successful performance on mental stress task. It should be mentioned that obtained results partially support Gellhorn's (1960; 1970) "tuning phenomenon" as a possible mechanism underlying stress response.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.6
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• pp.443-451
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• 2015

Design formula for estimating the wave loading on the perforated caisson having two wave chambers is yet available. In this study, the analysis results are presented with the experimental data for the wave force acting on such a breakwater model. Based on the experimental results, it was able to clarify the variation of wave action according to five different wave phases that are associated with peak wave loading at the three vertical walls. Then the force adjustment factor for double-chamber caisson was estimated, similarly as Takahashi and Shimosako (1994), which needs to be further validated with subsequent experiments and practical application in the field.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.11
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• pp.1485-1497
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• 2005

The purpose of this study was to define the mutual relationship between the explanatory variables of brand loyalty and consumer's fashion luxury brand loyalty, and ultimately to show a path model of fashion luxury brand loyalty. Especially this was focused on the relationship among social risk perception, symbolism involvement, marketer leading information search, and continuing brand loyalty. In the empirical study, a questionnaire was developed through the literature search and a survey was conducted both in on-line and off-line questionnaire simultaneously. Finally 291 data from males and females who had a buying experience of luxury brand goods were analyzed. The result showed the 4 significant paths of fashion luxury brand loyalty existed, such as social risk perception$\rightarrow$symbolism involvement, social risk perception$\rightarrow$marketer leading information search, symbolism involvement$\rightarrow$continuing brand loyalty, marketer leading information search$\rightarrow$continuing brand loyalty. And the explanatory factor which has the strongest influencing power to continuing brand loyalty was symbolism involvement. The powers of social risk perception and marketer leading information search to continuing brand loyalty were weaker than symbolism involvement. The findings of this study are expected to contribute to develop a theory on the consumer's loyalty to fashion luxury goods and marketing strategies for enhancing the brand loyalty.