• Title/Summary/Keyword: Youngsun

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GBAS Ground Testing and Performance Analysis at Gimpo International Airport (김포국제공항의 GBAS 지상시험 및 성능 분석)

  • Jeong, Myeong-Sook;Choi, Yunjung;Yun, Youngsun;Bae, Joongwon;Jun, Hyang-Sig;Lee, Young Jae
    • Journal of Advanced Navigation Technology
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    • v.19 no.1
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    • pp.22-32
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    • 2015
  • Ground based augmentation system (GBAS) is a next generation radio navigation aids to support precision approach of aircraft. Recently, airports installing GBAS and providing GBAS service are increasing all over the world. For the first time in Korea, SLS-4000 which is the GBAS ground equipment of Honeywell had been installed at Gimpo International Airport in 2013, and evaluated its functionality and performance of through the ground testing. This paper introduces a ground test and evaluation criteria on the CAT-I GBAS system, and describes testing methods for GBAS ground testing of Gimpo International Airport. In addition, detail testing methods and analysis results on major five of 12 ground test items are described.

Tele-operating System of Field Robot for Cultivation Management - Vision based Tele-operating System of Robotic Smart Farming for Fruit Harvesting and Cultivation Management

  • Ryuh, Youngsun;Noh, Kwang Mo;Park, Joon Gul
    • Journal of Biosystems Engineering
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    • v.39 no.2
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    • pp.134-141
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    • 2014
  • Purposes: This study was to validate the Robotic Smart Work System that can provides better working conditions and high productivity in unstructured environments like bio-industry, based on a tele-operation system for fruit harvesting with low cost 3-D positioning system on the laboratory level. Methods: For the Robotic Smart Work System for fruit harvesting and cultivation management in agriculture, a vision based tele-operating system and 3-D position information are key elements. This study proposed Robotic Smart Farming, an agricultural version of Robotic Smart Work System, and validated a 3-D position information system with a low cost omni camera and a laser marker system in the lab environment in order to get a vision based tele-operating system and 3-D position information. Results: The tasks like harvesting of the fixed target and cultivation management were accomplished even if there was a short time delay (30 ms ~ 100 ms). Although automatic conveyor works requiring accurate timing and positioning yield high productivity, the tele-operation with user's intuition will be more efficient in unstructured environments which require target selection and judgment. Conclusions: This system increased work efficiency and stability by considering ancillary intelligence as well as user's experience and knowhow. In addition, senior and female workers will operate the system easily because it can reduce labor and minimized user fatigue.

A Numerical Study on CUSUM Test for Volatility Shifts Against Long-Range Dependence (변동성 변화와 장기억성을 구분하는 CUSUM 검정통계량에 대한 실증분석)

  • Lee, Youngsun;Lee, Taewook
    • The Korean Journal of Applied Statistics
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    • v.27 no.2
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    • pp.291-305
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    • 2014
  • Persistence is one of the typical characteristics appearing in the volatility of financial time series. According to the recent researches, the volatility persistence may be due to either volatility shifts or long-range dependence. In this paper, we consider residual-based CUSUM tests to distinguish volatility persistence, long-range dependence and volatility shifts in GARCH models. It is observed that this test procedure achieve reasonable powers without a size distortion. Moreover, we employ AIC and BIC criteria to estimate the change points and the number of change points in volatility. We demonstrate the superiority of residual-based CUSUM tests on various Monte Carlo simulations and empirical data analysis.

Effect of Chinese Customer's Familiarity with Korean Fashion Brands on Satisfaction and Brand Loyalty (중국 소비자의 한국 패션브랜드에 대한 친숙성이 만족과 브랜드 충성도에 미치는 영향)

  • Liu, Bo;Ko, Soonhwa;Rhee, Youngsun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.40 no.4
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    • pp.763-774
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    • 2016
  • Companies have recently become interested in the importance of long-term relationships with customers because business-based marketing ideas of the past have evolved into long-term relationship-based marketing. Establishing a relationship with customers to a company is not a simple method to form a market of consumers and provider; it is now understood as an important factor directly connected to the survival of a company. This study is to help Korean fashion brands in China build an efficient strategy for sales promotion and loyal customers through the analysis of the effect of familiarity with Korean fashion brands on satisfaction and brand loyalty in a rapidly growing Chinese fashion market. An online questionnaire covering Korean fashion brands in China was completed by 377 Chinese male and female customers aged 20 to 39 years old from March 20 to March 27, 2014. Data analysis was performed by factor analysis and path analysis using SPSS 20.0 and AMOS. Both direct experiences and indirect experiences influenced brand familiarity. It showed that brand familiarity had a significant direct effect and an indirect effect through satisfaction on brand loyalty. A competitive advantage in the present Chinese fashion market requires that loyalty builds and that brand loyalty increases by creating a long-term relationship with customers when familiarity about the brand is induced.

Analysis of Features of Korean Eighth Grades' TIMSS 2015 Achievement in Chemistry (우리나라 중학생들의 TIMSS 2015 화학 영역 성취 특성 분석)

  • Kwak, Youngsun
    • Journal of The Korean Association For Science Education
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    • v.38 no.5
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    • pp.625-633
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    • 2018
  • The goal of this study is to investigate the features of Korean eighth graders' achievement and its trend in Chemistry in TIMSS 2011 and TIMSS 2015, and to explore its implications for Korean science curriculum and in teaching science. With three science educators and six science teachers, we analyzed the characteristics of Korean eighth graders' achievement in Chemistry by test-curriculum matching analysis. According to the trend analysis of science topics with released items for Chemistry in TIMSS 2015, Korean students' percentage for correct answers has dropped in topics such as regularities in chemical reactions, oxidation-reduction, etc. since these topics are covered after the ninth grade in the 2009 revised curriculum. For science cognitive domains, Korean students showed weaknesses in 'applying' domain in TIMSS 2015. Based on the results, we suggested implications for improvement in middle school chemistry curriculum and how to improve science teaching and learning for students' better science competencies and real-world application of science knowledge.

Resourcing of Methane in the Biogas Using Membrane Process (분리막을 이용한 바이오가스의 메탄 자원화)

  • Park, Young G.;Yang, Youngsun
    • Clean Technology
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    • v.20 no.4
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    • pp.406-414
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    • 2014
  • Biogas is a gaseous mixture produced from microbial digestion of organic materials in the absence of oxygen. Raw biogas, depending upon organic materials, digestion time and process conditions, contains about 45-75% methane, 30-50% carbon dioxide, 0.3% of hydrogen sulfide gas and fraction of water vapor. To achieve the standard composition of the biogas the treatment techniques like absorption or membrane separation was performed for the resourcing of biogas. In this paper the experimental results of the methane purification in simulated biogas mixture consisted of methane, carbon dioxide and hydrogen sulfide were presented. The composite membrane is manufactured within polysulfone in order to increase the separation performances for the gaseous mixtures of $CO_2$ and $CH_4$ which are main components of the biogas. The effects of feed pressures and mixed gas on the separation of $CO_2-CH_4$ by membrane are investigated. Chelate chemical was utilized to treat the purification of methane from the $H_2S$ concentration of 0.3%.

Reuse of Hydrogen Sulfide by Ferric Chelate Reaction of Food Waste Anaerobic Digestion Gas, Sulfur Recovery and its Economic Evaluation (킬레이트 착화학반응에 의한 음식물폐기물 혐기소화가스 중 황화수소의 제거와 황회수 및 경제성평가)

  • Park, Young G.;Yang, Youngsun
    • Clean Technology
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    • v.20 no.4
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    • pp.367-374
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    • 2014
  • Several experiments have been done to investigate the removal of hydrogen sulfide ($H_2S$) synthetic gas from biogas streams by means of chemical absorption and chemical reaction with 0.1-1 M Fe/EDTA solution. The roles of Fe/EDTA were studied to enhance the removal efficiency of hydrogen sulfide because of oxidizing by chelate. The motivation of this investigation is first to explore the feasibility of enhancing the toxic gas treatment in the biogas facility. The biogas purification strategy affords many advantages. For instance, the process can be performed under mild environmental conditions and at low temperature, and it removes hydrogen sulfide selectively. The end product of separation is elemental sulfur, which is a stable material that can be easily disposed with minor potential for further pollution. As the Fe-EDTA concentration increased, the conversion rate of hydrogen sulfide increased because of the high stability of Fe-EDTA complex. pH as an important environmental factor was 9.0 for the stability of chemical complex in the oxidation of hydrogen sulfide.

A Study on the Characteristics of Maximalism in Men's wear (남성복에 나타난 맥시멀리즘의 표현 특성 연구)

  • Kim, Ji Hye;Yoo, Youngsun
    • Journal of the Korean Society of Costume
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    • v.65 no.5
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    • pp.1-13
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    • 2015
  • The purpose of this study is to make a contribution to men's fashion by analyzing changes related to excessive and decorative expressions of latest men's wear design in the viewpoint of Maximalism, and using the results to develop a new fashion style. Results of the study are as follows: The characteristics of Maximalism in men's wear collection in the last 5 years can be classified as 'Fusion Maximalism, 'Decorative Maximalism', 'Exaggerative Maximalism', 'Humorous Maximalism', and 'Duplicative Maximalism'. The characteristics of each type of Maximalism can be summarized as follows: First, Fusion Maximalism creates new men's fashion style by fusing designs from different cultures in clothing items as well as dismantling gender boundaries in clothing design, and by having designs which transcends time and space. Second, Decorative Maximalism expresses ambiguous decadence by implementing feminine decoration that applies handicraft technique, as well as exaggeratedly using details and trimmings of contrasting images, and applying women's clothing items. Third, Exaggerative Maximalism represents extreme avant-garde that changes the idea of fashion design by changing the styling or the exaggerated silhouette. Fourth, Humorous Maximalism expresses not only the creation of new men's fashion look, but also expresses humanism with exaggerative enjoyment and pleasant ideas. Fifth, Duplicative Maximalism expresses creative design by implementing vivid images of different period and culture, and reproducing successful images of the past into modern fashion.

S&T Collaboration in Developing Countries: Lessons from Brazilian Collaboration Activities with South Korea

  • Fink, Daniel;Hameed, Tahir;So, Minho;Kwon, Youngsun;Rho, Jae Jeung
    • STI Policy Review
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    • v.3 no.2
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    • pp.92-110
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    • 2012
  • An active policy role is suggested for collaboration that will enhance national level Science and Technology (S&T) capabilities. In contrast, some studies see a limited role of policy support for collaborative S&T research at the individual level (including research groups or institutional levels) due to their self-organizing nature. Two views on S&T collaboration look at different levels but existing research largely ignores the context of developing countries. This paper shows how S&T collaborations between Brazil and Korea have developed over the past two decades. The paper indicates the gaps between initiation and the actual establishment of collaborative research at national and individual levels, differences in the focus areas of research, differences in resources and project planning, and the nature of collaborations. Collaborative research activities at the national level were initiated before the individual level but activated later than the individual level; in addition, the focus areas of research were laid down earlier at the national level with individual collaborations focused on different areas. Project types remained different at each level (i.e. top-down and bottom-up) or with a slightly changing mix. This study suggests appropriate policy measures (such as the timely and effective information collection of activities at different levels and proactive coordination) that could reduce the gaps in the timing and alignment of research areas. This paper also alludes to an evolutionary model to develop S&T collaboration among developing countries.

The effect of β-sitosterol proliferation and apoptosis in human uterine leiomyoma cells (계혈등(鷄血藤)의 Beta-sitosterol 성분이 자궁근종세포의 증식억제와 세포자멸사의 유도에 미치는 영향)

  • Park, Youngsun;Baek, Seunghee
    • The Journal of Korean Obstetrics and Gynecology
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    • v.18 no.1
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    • pp.181-191
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    • 2005
  • Purpose : ${\beta}$-sitosterol is kind of phytosterols or plant which are structurally similar to cholesterol. This study was aimed to investigate the inhibitory effect of the ${\beta}$-sitosterol on the proliferation of human uterine leiomyoma cells and the expression of gene related the mechanism of cell apoptosis. Methods : We counted the number of death cells treated with indicated time of the ${\beta}$-sitosterol and investigated cell death rate by cell count assay. Furthermore, flow cytometry analysis and DNA fragmentation assay were used to dissect between necrosis and apoptosis. and then we observed the differential gene expression by western blot analysis. Results : 1) The inhibitory effect on the growth of uterine leiomyoma cell treated with the ${\beta}$-sitosterol $16{\mu}M$ was increased in a time dependent. 2) The result of flow cytometry analysis, subG1 phase arrest related cell apoptosis was investigated 16.97% in uterine leiomyoma cell treated with the ${\beta}$-sitosterol $16{\mu}M$ and showed the fashion of proportional time dependent. 3) The gene expression of p27, p21 related cell cycle was increased according to increasing time interval but cyclin E-CDK2 complex was decreased expression. 4) The character of apoptosis, DNA fragmentation was significantly observed on the time dependent. 5) The expression of pro-caspase 3 and PARP were decreased dependent on treatment with time dependent. Conclusion : This study showed that the ${\beta}$-sitosterol have the inhibitory effect on the proliferation of human uterine leiomyoma cell and the effect was related with apoptosis.

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