• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.96-97
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• 2012

In nitride and oxide film deposition, sputtered metals react with nitrogen or oxygen gas in a vacuum chamber to form metal nitride or oxide films on a substrate. The physical properties of sputtered films (metals, oxides, and nitrides) are strongly influenced by magnetron plasma density during the deposition process. Typical target power densities on the magnetron during the deposition process are ~ (5-30) W/cm2, which gives a relatively low plasma density. The main challenge in reactive sputtering is the ability to generate a stable, arc free discharge at high plasma densities. Arcs occur due to formation of an insulating layer on the target surface caused by the re-deposition effect. One current method of generating an arc free discharge is to use the commercially available Pinnacle Plus+ Pulsed DC plasma generator manufactured by Advanced Energy Inc. This plasma generator uses a positive voltage pulse between negative pulses to attract electrons and discharge the target surface, thus preventing arc formation. However, this method can only generate low density plasma and therefore cannot allow full control of film properties. Also, after long runs ~ (1-3) hours, depends on duty cycle the stability of the reactive process is reduced due to increased probability of arc formation. Between 1995 and 1999, a new way of magnetron sputtering called HIPIMS (highly ionized pulse impulse magnetron sputtering) was developed. The main idea of this approach is to apply short ${\sim}(50-100){\mu}s$ high power pulses with a target power densities during the pulse between ~ (1-3) kW/cm2. These high power pulses generate high-density magnetron plasma that can significantly improve and control film properties. From the beginning, HIPIMS method has been applied to reactive sputtering processes for deposition of conductive and nonconductive films. However, commercially available HIPIMS plasma generators have not been able to create a stable, arc-free discharge in most reactive magnetron sputtering processes. HIPIMS plasma generators have been successfully used in reactive sputtering of nitrides for hard coating applications and for Al2O3 films. But until now there has been no HIPIMS data presented on reactive sputtering in cluster tools for semiconductors and MEMs applications. In this presentation, a new method of generating an arc free discharge for reactive HIPIMS using the new Cyprium plasma generator from Zpulser LLC will be introduced. Data (or evidence) will be presented showing that arc formation in reactive HIPIMS can be controlled without applying a positive voltage pulse between high power pulses. Arc-free reactive HIPIMS processes for sputtering AlN, TiO2, TiN and Si3N4 on the Applied Materials ENDURA 200 mm cluster tool will be presented. A direct comparison of the properties of films sputtered with the Advanced Energy Pinnacle Plus + plasma generator and the Zpulser Cyprium plasma generator will be presented.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.171-187
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• 2011

Due to the vitalization of the smart phones, mobile revolution has been started. The mobile revolution has elevated SNS service, which was once considered as just one of many communication tools, to the single most important communication method as well as diffusion of social commerce. Yet, there has not been an adequate study of the roles of SNS in the domestic social commerce market, which has gotten a lot of spotlights. Therefore, the purpose of this study is to investigate the influence of various characteristics of social commerce that it has an impact on the purchase intension as well as the moderating effects of SNS. For these purposes, this study has drawn up the characteristics of social commerce in cost cutting, impulse buy, social influence, decision support, word of mouth effect and etc. to prove the interaction effect of SNS. The regression analysis showed that the characteristics of all the social commerce are related to the dependent variable. As a result of drawing up the interaction effect of SNS, it has shown that the cost cutting and word of mouth have significant influence in the social commerce diffusion as the usage of SNS increased. In conclusion, the main implication of this study is to provide the basic grounds for social commerce business strategy as it investigated the characteristics of SNS and its relation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.11
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• pp.984-997
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• 2015

Chang'e-3 consisting of a lunar lander and exploration rover was launched on December 1, 2013 aboard a Long March 3B rocket flying from Xichang space launch center. Chang'e-3 was inserted into the lunar orbit after about a 5-day transit to the Moon and landed on the targeted landing site after orbiting around the Moon for 8 days. The successful landing of the Chang'e-3 gives a lot of help to analyze the future needs of the subsystem technologies and to figure out the trajectory from launch to lunar landing as well as operation sequences in the development of Korean lunar exploration is scheduled. Therefore, the configuration and analysis of overall mission of Chang'e-3 is performed based on the public information from the press and website. As a result, overall mission trajectory is reconstructed by solving boundary condition and then estimating control variable. Visibility status and eclipse status also analyzes so communication and power charge condition is as good as to operate lunar lander. Mass budget of the lander is derived using ${\Delta}V$ according to specific impulse.

• The Journal of the Korea Contents Association
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• v.12 no.9
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• pp.479-488
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• 2012

The purpose of this study was to determine the impact in visitors' spending on two separate local festivals, and to present the improved market strategies to attract visitors to revisit the local festivals. This study was also intended to suggest the ways to increase the competitiveness and revitalize the local festivals by improving the existing attractions and creating new attractions based on the visitors' evaluation. On the purpose of the study, we studied the visitors of two local ricefests, Icheon Rice Cultural Festival and Rice Festival in Jincheon Chungbuk, and estimated the determinants influencing the visitors' spending to the festivals by applying Tobit model. Finally, to estimate the behavioral differences in visitors of the two festivals, we compared the estimated determinants for the visitors of each festival by using Log-likelihood Ratio, and analyzed the differences in the factors influencing the visitors' spending. Summarizing the propensity of visitor's spending to local festivals, visitors of two rice festivals buy or tended to buy things on impulse. Therefore, festival industry needs to take measures to efficiently accommodate their expenditures from the stage of designing festivals.

• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.23-33
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• 2020

As the scale of the economy expands, the number of cases of damage in enclosed spaces such as tunnels is increasing due to the accident of transportation vehicles of dangerous substances such as explosive flammable materials that have increased rapidly. In the case of road tunnels in particular, in the aspect of protection against the long-winding trend and the environment in the downtown area, the number of cases of passing through the downtown area increases, and securing the safety of structures against unexpected extreme disasters such as explosions during tunnel passage is very urgent. For this reason, developed countries are already conducting a review of internal bombardment, but there are almost no evaluation and countermeasures for explosion risk in Korea. Therefore, in this study, in order to evaluate the explosion safety of road tunnels, a boiling liquid explosive explosion (BLEVE), which is considered to have the greatest explosion load among vehicles driving on the road, is set as a reference explosion source, and the equivalent TNT explosion load is used for simulation of the explosion. A method of conversion was presented. In addition, by applying the derived explosion load, dynamic behavior simulation was performed by assuming various variables for the tunnel, and the explosion safety of the tunnel was analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1565-1573
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• 2011

In this paper, we present a MIMO-OFDM broadband power line communication (BPLC) for Smart Grid and its associated applications and analyze its performance over the 3-phase 4-wire power line channels. For practical BPLC system simulation, we adopt the statistical power line fading channel model instead of the existing deterministic fading channel models (Zimmermann model, MTL model, and so on). In this paper, we implement $2{\times}2$ and $3{\times}3$ MIMO schemes using 3-phase 4-wire power lines. We investigate the capacity loss and BER performance of the proposed MIMO system by considering the effect of cross-talk between antenna paths. We choose space-frequency coding in order to reduce frequency interference between subcarriers and employ maximum ratio combining (MRC) that achieves both multiple antenna path diversity gain and multiple fading path diversity gain. We evaluate the proposed system performance through computer simulation in terms of the impulse noise index and the capacity loss ratio and compare the different signal combining schemes including MRC, equal gain combing (EGC), and selection combining (SC).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.161-169
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• 2020

The factors influencing the quality of life of physical and mental health in middle-aged women were examined. Secondary analysis was conducted using the data from the 2016 Korea Health Panel data. Method: The Korea Health Panel data 2016 were collected from February to August 2016 by the Korea Institute for Health and Social Affairs and the National Health Insurance Corporation and included 2,437 people who responded to the questionire. Using the SPSS Win program, the data were analyzed using a t-test, ANOVA, Pearson correlation coefficient, and multiple regression analysis. For physical health, the factors affecting the HRQoL were hearing problems, visual problems, eating problems, and physical activity. For mental health, the factors affecting HRQoL were suicidal impulse, stress subjective health. Conclusion: The results indicated that to improve the HRQoL of middle-aged women, a psychological nursing intervention program will be needed to reduce the stress and suicidal thoughts and improve the positive cognitive attitude and subjective health condition.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.336-344
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• 2020

The purpose of this study was to investigate the PAI profile of the beauty major students. They were used through the PAI inspection result of 298 university students located in the chungcheong province in 2019. The results are summerized as follows; First, when comparing the average scale of college students majoring in beauty with those of college students majoring in general, college students majoring in beauty displayed a higher profile type in clinical scale than those of university students in general, with significant differences in SOM and ALC. Second, SOM, PAR, AGG, SUI that were significant when comparing beauty majors and general majors to navigate the PAI scale that significantly predicts beauty majors. As a result of conducting stepwise regression analysis on the four factors as a search factor, the scale of SOM is extracted, and it becomes a diversion that can predict college students in the beauty major. Therefore, beauty majors are more obsessed with physical problems than the ordinary students, and have an impulse-oriented behavior. These results will be used as materials for selecting, managing, educating or consulting a student majoring in beauty and will provide many implications for career choices after graduation.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.109-118
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• 2018

Korea Aerospace Research Institute has developed a staged combustion cycle rocket (SCCR) engine with high specific impulse to send a 3-ton class satellite into geostationary orbit while conducting a Korean Space Launch Vehicle (KSLV) II project. The SCCR engine is different from the KSLV-II engine, which is an open cycle engine using a gas-generator. The SCCR engine with a closed cycle engine is composed of a pre-burner, a turbo pump, and a main combustor. The technology demonstration model (TDM0) was assembled and tested in the 7ton-class engine combustion test facility of Naro Space Center, and the combustion test was successfully conducted.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.51-56
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• 2008

The waveform inversion for isotropic media has ever been studied since the 1980s, but there has been few studies for anisotropic media. We present a seismic waveform inversion algorithm for 2-D heterogeneous transversely isotropic structures. A cell-based finite difference algorithm for anisotropic media in time domain is adopted. The steepest descent during the non-linear iterative inversion approach is obtained by backpropagating residual errors using a reverse time migration technique. For scaling the gradient of a misfit function, we use the pseudo Hessian matrix which is assumed to neglect the zero-lag auto-correlation terms of impulse responses in the approximate Hessian matrix of the Gauss-Newton method. We demonstrate the use of these waveform inversion algorithm by applying them to a two layer model and the anisotropic Marmousi model data. With numerical examples, we show that it's difficult to converge to the true model when we assumed that anisotropic media are isotropic. Therefore, it is expected that our waveform inversion algorithm for anisotropic media is adequate to interpret real seismic exploration data.