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      • 외국인 주식거래량이 국내투자자 행동에 미치는 영향분석

        이성현,이근수 안성산업대학교 1999 論文集 Vol.31 No.-

        It was studied how the trading volume trend of foreign investors, whose market leading power have been continuously increasing sine '92 stock market opening, has been influencing korean stock market, interacting with domestic market participants; institutional investors and private investors. I analize the influence, volatility of korean stock composite index using GARCH model which is hypothesizeing the heterokedasticity of the error terms n spite that the homoscedasticity is currently used. To track down the interactivity of each market participants, Greanger Causality Test was carried on. The result of the analysis are follows. First, as a result of the analysis using the Simple Regression Analysis Model the volatility of stock composite index was influenced by private investors' bullish trading volume in case of buying volume, on the contrary by institutional investors' bearish trading volume in case of selling volume. Second, because of the direct influence of foreign investors to the market was not found with the result of regression analysis and GARCH model, Granger Causality Test was carried on to find to interactive influence of each market participant. Finally, foreign investors has been playing an important role as a market participant in the korean stock market and their influence has been continuously increasing. As a result of the above analysis, with th foreign investors' participation in Korean stock market their trading pattern has been an important information and influencing domestic market participants' trading pattern. Especially, private investors trading pattern whose investment information fall behind, has been highly influenced by foreigners'. and simply subjected to the foreigners' trading pattern, private investors influenced by foreigners'. And simply subjected to the foreigners' trading pattern, private investors are losing the probability of achieving excess returns in the market.

      • KCI등재후보

        전동식 조향 장치의 성능 평가를 위한 신경 근육계 기반 운전자 모델 개발

        이성현,이동필,이재풍,채흥석,이명수,이경수,Lee,,Sunghyun,Lee,,Dongpil,Lee,,Jaepoong,Chae,,Heungseok,Lee,,Myungsu,Yi,,Kyongsu 한국자동차안전학회 2017 자동차안전학회지 Vol.9 No.3

        This paper presents a lateral driver model with neuromuscular system to evaluate the performance of electric power steering (EPS). Output of most previously developed driver models is steering angle. However, in order to evaluate EPS system, driver model which results in steering torque output is needed. The proposed lateral driver model mainly consists of 2 parts: desired steering angle calculation and conversion of steering angle into steering torque. Desired steering angle calculation part results in steering angle to track desired yaw rate for path tracking. Conversion of steering angle into torque is consideration with neuromuscular system. The proposed driver model is investigated via actual driving data. Compared to other algorithms, the proposed algorithm shows similar pattern of steering angle with human driver. The proposed driver can be utilized to efficiently evaluate EPS system in simulation level.

      • KCI등재

        지오파이버로 보강된 도로기초의 구조적 적정성 평가 연구

        이성현,김인태,박현수,박성완 한국도로학회 2019 한국도로학회논문집 Vol.21 No.2

        PURPOSES : Recently, there has been an increase in the use of discrete randomly distributed fiber materials for reinforcing pavement foundations. However, very limited study has been made on this from the perspective of pavement engineering. Therefore, this study evaluates the performance of soil-geofibers used in pavement foundations as well as the effects of stress dependency with various mixtures. METHODS: To estimate the behavior of soil-geofiber mixtures under traffic loadings, laboratory resilient modulus data for the mechanical characteristics of geofiber mixtures were used, and they were adopted to evaluate the structural response and analyze the stress dependency through 2-D finite element analysis. As the host materials, poorly graded and uniformly graded sand were selected, and each soil was mixed with three different types of fiber, namely monofilament, fibrillated, and tape. RESULTS: The stress dependent response on resilient modulus and Poisson's ratio were mainly considered by conducting linear and nonlinear elastic analyses on various geofiber mixtures. As a result, it was found that the response and yield function of geofiber mixed layers in pavements were affected considerably depending on the gradation of the soils and the confinement conditions. A small change was found when the particle size was homogenized. CONCLUSIONS : From this, it can be concluded that the finite element model with stress dependency is suitable for estimating the performance on geofiber mixtures. It is also noted that all the responses of geofiber mixtures were relatively sensitive to the gradation of host soils. This indicates that the effects of the nonlinearity and stress-dependency of geofiber mixtures under repetitive loadings could be substantial.

      • KCI등재

        양돈분뇨 퇴비화시 비료성분, 중금속 및 섬유소 함량 특성

        이성현,정광화,이동준,이동현,곽정훈 한국폐기물자원순환학회 2019 한국폐기물자원순환학회지 Vol.36 No.6

        Swine manure has been recognized as an organic source of composting material, and much research has been conductedfor its efficient utilization and treatment. This study was carried out to analyze the changes in fertilizer composition, heavymetals, and fiber content during composting by mixing pig manure with sawdust. The test was set as a simplesedimentation type composting and a ventilation sedimentation type composting. In EXP1 and EXP2, 100 L and 150 Lof air were blown for each cubic meter of composting material. The composting fermentation period was set at four weeks. The fermentation temperature during the composting process increased from 67oC to 75oC between 1 and 2 days. It wasjudged that this was due to the rapid increase in the abundance of thermophilic bacteria. The contents of the fertilizerduring the composting period were found to be largely changed in EXP1 and EXP2 but not in the REF. Cadmium, mercury,and lead were not detected in throughout the test. The coefficient of variation in copper content in the REF, EXP1, andEXP2 was 0.033, 0.058, and 0.071, and the coefficient of variation in zinc content was 0.025, 0.041, and 0.079. Copperand zinc contents did not change significantly during the composting period. After fermentation, the heavy metal contentof the compost was less than the value determined by the composting organic fertilizer standard. The variation patternsin NDF, ADF, and cellulose contents were similar to one another during the composting period. The change in fiber contentwas larger in EXP1 and EXP2 than in the REF.

      • KCI등재SCIESCOPUS

        RF Extraction of Gate-Voltage Dependence of the Overlap and Fringing Capacitances in Deep-Submicron MOSFETs

        이성현 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.21

        The gate-voltage dependent radio-frequency (RF) data of the source/drain overlap and fringing capacitances in deep-submicron metal-oxide-semiconductor field-effect transistors (MOSFETs) have been accurately extracted using a new RF method. The outer fringing capacitance is determined by curve-fitting a gate voltage-dependent model equation to the measured gate capacitance data in the accumulation region. RF extraction of the overlap capacitance is performed using a theoretical equation and a linear regression of the measured gate capacitance versus the gate length. Using these extracted capacitances, the inner fringing capacitance is also determined.

      • 조사료 래핑용 스트레치 필름의 물리적 특성에 관한 연구

        이성현,장유섭,박원규,최광재,김종근 한국축산시설환경학회 1999 축산시설환경학회지 Vol.5 No.2

        Recently more dairy farmers are interested in the utilization of stretch film for wrapping silage material. Most of stretch film are imported from abroad and one domestic product was developed, but its quality has not yet been tested. Therefore this study was executed to offer basic data on this material to the farmers. Measured items were tensile load, extension ratio, and tear propagation strength of stretch films. Comparisons were made among the white color of domestic product(Kw), and white(Fw), black (Fb) and green color(Fg) of foreign products. The result were summarized as follows: 1. Tensile loads of lengthwise direction in stretch films were 557.4, 377.4, 282.6 and 398.4kgf/$\textrm{cm}^2$ in Kw, Fw, Fb and Fg, respectively, and tensile loads of width direction were 415.9, 418.1, 360.2 and 433.0kgf/$\textrm{cm}^2$ in Kw, Fw, Fb and Fg, respectively. 2. Extension ratios of lengthwise direction were 650, 462.5, 512.5% and 537.5% in Kw, Fw, Fb and Fg, respectively, Extension ratios of width direction were 930, 962.5, 950 and 1,000% in Kw, Fw, Fb and Fg, respectively. 3 Tear propagation strength of lengthwise direction 187.9, 148.9, 157.3 and 142.8kgf/cm, and tear propagation strength of width direction were 141.4, 129.8, 140.4 and 106.6kgf/cm in Kw, Fw, Fb and Fg, respectively. 4. In the light transmittance, there was no difference between white and green color stretch film, but it was very low in black one. Therefore, it is thought that research on quality of roll bale silage treated with each stretch film would be needed.

      • KCI등재

        돈분의 고형 연료화를 위한 특성 분석

        이성현,유병기,주선이,강연구,정광화 한국폐기물자원순환학회 2016 한국폐기물자원순환학회지 Vol.33 No.7

        It is projected that swine manure solids can be used for heating agricultural facilities. Therefore, this study focused on the possibilities of using swine manure as a solid fuel instead of composting it. Moisture content, ash content, volatile content, calorific value, TGA (thermogravimetric analysis), and elements in the swine manure were determined. After dehydrating the manure completely in a drying oven, its calorific value and ash content were measured. They appeared to be 3,517 kcal/kg and 16.6%, respectively, which satisfies the standard value of livestock solid fuel: heating value of 3,000 kcal/kg or above and ash content of 30% or below. Based on this result, it is concluded that using swine manure solids as a solid fuel is possible. Furthermore, when the chemical elements of C, H, O, N, S, Cl, etc. in the manure were analyzed, there was 33.75 ~ 45.98% of carbon and 31.55 ~ 41.20% of oxygen, which indicates that most of the manure was composed of combustible materials. However, there were cases where the percentage of water content in the manure exceeded 70%, implying that costs for dehydration would become expensive because it needs to be lowered to 20% in order to be used for energy source. Therefore, in order to use the swine manure as an energy source, minimizing the manure's percentage of water content at the farm without any outside financial input is the biggest task to be solved.

      • KCI등재

        Abdominal Subcutaneous Fat Thickness Measured by Ultrasonography Correlates with Hyperlipidemia and Steatohepatitis in Obese Children

        이성현,김동완,백민영,차한,김연석,류일,김윤미 대한소아소화기영양학회 2015 Pediatric gastroenterology, hepatology & nutrition Vol.18 No.2

        Purpose: The aim of this study is to evaluate the relationship between abdominal subcutaneous fat thickness meas-ured by ultrasonography (US) and serum lipid profile and liver transaminases in obese children.Methods: One hundred and sixty-six children diagnosed with obesity from May 2001 to December 2013 were included in this study. Data on serum lipid profile and liver transaminases were collected from clinical records. Abdominal subcutaneous fat thickness and grade of hepatic steatosis were evaluated by US.Results: Of the 166 children, 107 were diagnosed with hepatic steatosis by US, 46 with grade I, 56 with grade II, and five children with grade III. According to the grade of hepatic steasosis, the average values of midline abdominal subcutaneous fat thickness and right flank abdominal subcutaneous fat thickness measured 2.9±0.8 cm and 1.9±0.7cm in the normal group, 3.3±0.8 cm and 2.0±0.7 cm in grade I, 3.8±0.8 cm and 2.3±0.8 cm in grade II, and 4.1±0.8cm and 2.8±1.4 cm in grade III, respectively. Abdominal subcutaneous fat thickness correlated with grade of hepatic steatosis (p<0.01). In addition, abdominal subcutaneous fat thickness correlated with concentration of serum lipids and liver transaminases in the age group of 12-14 years (p<0.01).Conclusion: Abdominal subcutaneous fat thickness measured by US can be used as a reliable predictor of possible hyperlipidemia and steatohepatitis in children, especially during the adolescent stage.

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