• Journal of the Korean Solar Energy Society
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• v.38 no.2
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• pp.45-53
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• 2018

For the preliminary step for estimating the performance of roof-type photovoltaic system in urban areas, we analyzed the solar radiation reduction ratio by shadow effect by buildings using DSM (Digital Surface Model) and GIS (Geographical Information System) tools. An average loss by the shadow is about 19% in Seoul. The result was related to the building density and distribution. Monthly results show that the winter season (December and January) was more affected by the shading than during the summer season (June and July). It is expected that useful empirical formulas can be made if more detailed correlation studies are performed.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.79-88
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• 2018

Previously, there have been many studies on the fraud of employees, internal customers of the company, but there have been a lot of studies on military affairs that are closely related to the improvement of army's combat power. Therefore, this study investigates how communication satisfaction is influenced by the characteristics of SNS. For empirical verification, 240 soldiers were surveyed in this study. The analysis method was to investigate the correlation between each variable using the Structural Equation Model (SEM). The results of this study show that the SNS characteristics have a positive effect on the overall model related to organizational communication satisfaction. Organizational communication satisfaction has a positive impact on military fraud and organizational communication satisfaction has been shown to mediate between army and SNS traits. Through this research, we intend to promote the morale of soldiers by activating communication among group members using appropriate level of social networking.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.797-802
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• 2020

Over the past few years, smart devices, including smartphones, have been continuously required by users based on portability. The performance is improving. Ubiquitous computing environment and sensor network are also improved. Due to various network connection technologies, mobile terminals are widely used. Smart terminals need technology to make energy monitoring more detailed for more stable operation during use. The smart terminal which is light in small size generates the power shortage problem due to the various multimedia task among the terminal operation. Various estimation hardwares have been developed to prevent such situation in advance and to operate stable terminals. However, the method and performance of estimating the remaining amount are not relatively good. In this paper, we propose a method for estimating the remaining amount of smart terminals. The Capacity Estimation of lithium ion cells for stable operation was estimated based on machine learning. Learning the characteristics of lithium ion cells in use, not the existing hardware estimation method, through a map learning algorithm using machine learning technique The optimized results are estimated and applied.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.5
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• pp.45-53
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• 2000

This paper presents an analysis of the dynamical behavor in the chaotic neuron fabricated using 0.8${\mu}{\textrm}{m}$ single poly CMOS technology. An approximated empirical equation models for the sigmoid output function and chaos generative block of the chaotic neuron are extracted from the measurement data. Then the dynamical responses of the chaotic neuron such as biurcation diagram, frequency responses, Lyapunov exponent, and average firing rate are calculated with numerical analysis. In addition, we construct the chaotic neural networks which are composed of two chaotic neurons with four synapses and obtain bifurcation diagram according to synaptic weight variation. And results of experiments in the single chaotic neuron and chaotic neural networks by two neurons with the $\pm$2.5V power supply and sampling clock frequency of 10KHz are shown and compared with the simulated results.

• Corrosion Science and Technology
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• v.19 no.3
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• pp.131-137
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• 2020

A number of piping components in the secondary system of nuclear power plants (NPPs) are exposed to aging mechanisms, such as flow-accelerated corrosion (FAC), cavitation, flashing, solid particle erosion, and liquid droplet impingement erosion. Those mechanisms may lead to thinning, leaking, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 in the USA in 1986 and Mihama unit 3 in Japan in 1994, pipe wall thinning management has emerged as one of the most important issues in the nuclear industry. To manage pipe wall thinning, a foreign program has been utilized for NPPs in Korea since 1996. As our experience and knowledge of pipe wall thinning management have accumulated, our program needs to reflect our experience, requests from users, and the result of recent experiments using Flow Accelerated Corrosion Testing System (FACTS). FACTS is the empirical experimental facility developed by Korea Atomic Energy Research Institute (KAERI) for tests. Accordingly, KEPCO-E&C developed a 3D-based pipe wall thinning management program called ToSPACE in 2016. This paper describes a comparison between the FAC analysis results using ToSPACE and the experimental results using FACTS to verify their applicability to pipe wall thinning management in NPPs.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.163-172
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• 2002

The turbine system composed of a nozzle and a rotor is used to drive turbopumps while gas passes through the nozzle, potential energy is converted to kinematic energy, which forces the rotor blades to spin. In this study, an aerodynamic design of a turbine system is investigated using compressible fluid dynamic theories with some pre-determined design requirements (i.e.,pressure ratio, rotational speed, required power etc.) obtained from a liquid rocket engine (L.R.E.) system design. For simplicity of a turbine system, impulse-type rotor blades for open type L.R.E. have been chosen. Usually, the open-type turbine system requires low mass flow rate compared to the close-type system. In this study, a partial admission nozzle is adopted to maximize the efficiency of the close-type turbine system. A design methodology of the a turbine system has been introduced. Especially, a partial admission nozzle has been designed by means of simple empirical correlations between efficiency and configuration of the nozzle. Finally, a turbine system design for a 10 ton thrust level of L.R.E is presented.

• Informatization Policy
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• v.20 no.3
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• pp.63-85
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• 2013

Drawing on Protection Motivation Theory(PMT), this study attempts to clarify antecedents that influence the intention to protect individuals' privacy on the Internet. Protection motivation forms through individuals' cognitive appeal involving threat and efficacy. Then protection motivation causes privacy behavioral change. Protection motivation factors are established privacy trust and privacy risk, which are related to privacy attitude and belief. This proposed model is empirically analyzed by utilizing structural equation analysis(SEM). According to the result of the empirical analysis, it is founded that almost paths have statistically significant explanatory power except path from efficacy to privacy risk and path from privacy trust to privacy behavioral intention. This study shows powerful evidence of antecedent factors based on protection motivation of individuals' privacy behavioral intention in online environment.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.315-323
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• 1982

The measurement of cell constant in a diaphragm-cell method is the most important factor. In order to get the correct cell constant, the diffusion coefficients of potassium chloride were measured, at various concentration and temperature of potassium chloride solution, and at the stirring rate in the cell. The pseudo-binary diffusion coefficients of organic aroma component (benzaldehyde) in sugar solution has been measured at various concentration and temperature with the cell constant obtained above. Experimental results were compared and discussed with the semi-empirical epuations from literatures. And, especially, the diffusion coefficient of benzaldehyde, $D_{ba}$ for a small solute diffusing in a viscous solvent of larger molecules is proportional to the -0.82 power of the viscosity of aqueous sugar solution, ${\mu}$ at constant temperature, $D_{ba}{\mu}^{0.82}=constant$.

• Journal of Fashion Business
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• v.19 no.5
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• pp.110-127
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• 2015

This study probed into the fashion styling of modern girls who led fashion and revealed power of woman as the center of modernization in Korea. Methods included the theoretical study based on fashion related newspaper articles at the time, specialized publications, advance researches, and internet data and the empirical study that involved contents analysis centering on visual data, expert evaluation, and styling development and presentation. The image of Korean modern girl analysis found in the order of modern image, elegant image, classic image, mannish image, romantic image. The aesthetic characteristics could be classified into sensual classicism, modern elegance, feminist epicenism, and romantic simplicity. The theme was 'Retro Modern' and a total of 4 styles were applied. 'Progressive Tradition' expressed the aesthetic characteristics of sensual classicism and it gave a modern reinterpretation of the seamless one-piece skirt which is the modified Korean clothes of Korean modern girls. 'Luxe Beauty' expressed the aesthetic characteristics of modern elegance, and it developed the long and slim style which was popular in the 1930's in a trendy way. 'Dressy Avant-garde' expressed the aesthetic characteristics of feminist epicenism, and it suggested the mannish style Western clothes that Korean modern girls wore by following recent fashion trend. 'Minimal Couture' expressed the aesthetic characteristics of romantic simplicity and it presented the garçonne look which was popular in the 1920's by following recent trend.

• The Korean Journal of Financial Management
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• v.21 no.2
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• pp.1-25
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• 2004

From the perspective of corporate governance, we examine the acquirers' performance of mergers and acquisitions. The empirical results of our study show that outside active shareholders, such as block shareholders or institutional shareholders, affect acquirers' performance in M&A's : the ownership of outside active shareholders is positively correlated with the performance of acquirers. However, the ownership of insiders, such as that of encumbent manners or major shareholders, does not have any significant effect on the performance of M&A's. We also found that the ownership of foreign investors increased its explanatory power after the financial crisis of Asia. Since the current literature concludes that the improvement of corporate governance would enhance the shareholders' wealth, the results of our study implies that outside active investors, rather than insiders, are playing an important role in the corporate governance.