• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2012.03a
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• pp.104-109
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• 2012

• Bulletin of the Korean Space Science Society
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• 2002.05b
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• pp.57-57
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• 2002

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.35.1-35.1
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• 2010

천체는 천구의 북극을 중심으로 지구자전에 의하여 반시계방향으로 일주 운동을 한다. 적도의식 망원경의 최대 장점은 극축이 정확히 맞추어졌다면 접안렌즈 중앙에 적위축 조정으로 정확히 원하는 천체를 위치시키고, 적경축을 지구자전축에 동기 시켜 회전시키면 어떠한 대상이라도 추적이 가능하다. 본 연구에서는 Hardware적으로 적경축 구동을 지구 자전속도에 동기 시키는 제어회로를 설계하였다.

• Journal of Astronomy and Space Sciences
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• v.19 no.2
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• pp.133-140
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• 2002

Space Physics Sensor onboard the KOMPSAT-1, which was launched at 1999, had transmitted ionospheric data during the solar maximum from June 2000 to August 2001. When the KOMPSAT-1 has passed the equatorial region, equatorial bubbles, in which the electron density abruptly decreases, had frequently been detected. Statistical analysis of the data obtained during the entire operational period shows equatorial bubbles frequently occur across the Atlantic region where the geomagnetic field strength is weak. Also, equatorial bubbles occur more frequently for lower Kp index. The results are in good agreement with the previous observations by DMSP satellites and radio experiments at the Peruvian sector The correlation between electron density and the electron temperature shows various behaviors from event to event.

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.51-58
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• 2000

This study was performed to accumulate database for natural sulfur emissions in the Yellow Sea region of Korea. The atmospheric concentrations of dimethylsulfide(DMS) were measured during two intensive field experiments (April and September 1999) from Duk-Juk Island located in the Yellow Sea. Ship-measurement of DMS was made additionally between Chungdo(China) and Inchun(Korea) across the Yellow Sea during June 1999. The mean(and ISD) of DMS concentrations in Duk-Juk Island during two field campaigns was $24.0{\pm}40.5$(n=40, April) and $61.1{\pm}37.9$ pptv(n=35, September), respectively. The atmospheric DMS measured from ship experiments was generally low and close to the background concentrations in the open sea area. The temporal distributions of DMS concentration were complicated in some sense but comparable to those of ambient meteorological parameters. On the basis of our measurements of atmospheric DMS(and evidence found from previous studies), the sea-to-air flux of DMS in the Yellow Sea is estimated to be about 4Gg S/yr. This amount of natural S emissions is relatively lower than the estimates derived for Cheju Island. Therefore, additional experiments may be desperate to derive more reliable figures for natural sulfur emissions in the Yellow Sea region.

• Journal of Astronomy and Space Sciences
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• v.19 no.2
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• pp.123-132
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• 2002

The electron density and temperature in the topside ionosphere are observed by the ionosphere Measurement Sensor (IMS) onboard the KOMPSAT-1, which has the sun-synchronous orbit of the altitude of 685 km and the orbital inclination of $98^{\circ}$ with a descending node at 22:50LT. Observations have been analyzed to determine the seasonal variations of the electron density and temperature in the low-latitude region. Only the night-time (22:50LT) behavior on magnetically quiet days (Kp < 4) has been examined. Observations show a strong longitudinal and seasonal variation. Generally, in the dip equator the density increases and the temperature decreases. In equinox the latitudinal distributions of the electron density and temperature are quite symmetric about the dip equator. However, the local maximum of the density and the local minimum of the temperature shift toward the Northern hemisphere in summer solstice but the Southern hemisphere in winter solstice. Such variations are due to the influences of field-aligned plasma transport induced by F region neutral wind. Compared with the IRI95 model, the observed electron density and temperature show significant differences from those predicted by the IRI95 model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.1
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• pp.80-87
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• 2001

Global robust diagnostic models are established based on MOM of GFDL to study the circulation in the world ocean. The horizontal grid sizes 1/2 degree, and the vertical water column is divided into 21 levels. The hydrographic data are taken from Levitus et al.(1994) and the wind stress from Hellerman and Rosenstein (1983). Based on the model results the horizontal volume, heat and salt transports across some representative sections are calculated. The preliminary results show that Though the cross-equator volume transports in the Atlantic, Indian and Pacific Oceans are all small, the heat transports across equator in the Atlantic are northward. This is clearly a result of the southward flow of the North Atlantic Deep Water and the northward compensating warm flow in the upper layer. The annual mean of the cross-equator heat transport in the Pacific Ocean from the present model is significantly lower than that calculated by Philander et at. (1987). This might indicate the importance of the Indonesian Throughflow in the heat transport in the Pacific Ocean. Our calculation shows that the heat transport through the Indonesian Archipelago is 0.5 PW, which is comparable with the poleward heat transport in the North Atlantic and Pacific Oceans. The difference in heat transports across the sections 5 and 6 demonstrates the important role of the Agulhas Current in the heat balance of the world ocean.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.204-209
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• 1998

The acceleration of the performance of machine tools influences the development of the semi-conductor and optical technology as the development of NC and measurement technology. We can mention that a traction role of the acceleration for the development like that depends on the development of the measurement technics Stylus instrument method, STM, SEM, Laser interferometer method which are used for measuring the quasi-static error of machine tools. Because the measurement has been done to unload condition without considering of mechanical stiffness in the case of machining center as we measure the quasi-static error of machine tools on general studies, people who works on the spot has many problems on the data value. Therefor we will help working more accurately on the spot by measuring, analyzing, displaying the deflection of the table and support shaft when we load on the table and the support shaft of machining center using laser interferometer. Also we try to settle new conception of the measurement method and more accurate grasp of the deflection tendency by verifing the tendency of the error measured through the comparison of the simulated error using ANSYS, a common finite element analysis program, which is able to measure heat deformation, material deformation, and error resulted form this study.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.31-31
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• 2003

Equatorial Plasma Bubble(EPB)은 적도 지역에서 Rayleigh-Taylor Instability에 의해 발생하는 이온층 플라즈마의 불안정성 현상으로, 주변의 플라즈마 밀도에 비해 좁은 영역에서 플라즈마 밀도가 급격하게 떨어지는 현상을 말한다. 지역적으로 보면, 겨울철에는 대서양 지역에서 집중적으로 발생하고 여름철에서는 태평양 지역에서 많이 관측된다. 이러한 불안정 현상은 단파 통신 장애를 유발할 수 있기 때문에 많은 연구 대상이 되어왔지만, 아직까지 태양 활동이나 지자기 변화에 의한 상호 연관성이 규명되지 못 하고 있다. 이것은 Rayleigh-Taylor Instability를 발생시키는 여러 인자들이 매우 복잡하게 관련되어 있기 때문인데, 본 연구에서는 특정 지역에서 발생하는 EPB에 한정하여 태양 활동과의 상호 연관성에 대해 분석하고자 하였다. 또한 단순한 발생 빈도에 대한 통계적인 처리가 아닌, EPB하나 하나에 대한 특성을 분석함으로써 EPB의 발생과 관련한 보다 명확한 분석이 가능하게 되었다. 분석에 필요한 data는 KOMPSAT-1의 Langmuir Probe(LP)에 의해 2000년에서 2001년 사이에 얻은 이온층의 전자 밀도를 사용하였는데, KOMPSAT-1의 LP는 같은 기간 활동한 다른 위성에 비해 좋은 시간 분해능을 가지고 있기 때문에 EPB의 통계 처리에 적당한 것으로 생각되었다.

• The Korean Journal of Malacology
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• v.12 no.1
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• pp.19-31
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• 1996

국내 11개 지역(경기도 옹진군 덕적도, 경기도 의정부시 소요산, 강원도 춘천시, 충청남도 태안군 안홍, 경상북도 울릉군 울릉도, 전라북도 부안군 변산, 전라남도 신안군 홍도, 흑산도 비금도, 진도, 제주도)에서 채집된 달팽이 (A. despecta sieboleiana)를 대상으로 외부형태 분석과 동위효소를 검출하여 각 지역 집단간의 형태적, 유전적 유연관계와 변이 정도를 연구한 결과는 다음과 같다. 외부형태에 의한 집단간 유연관계는 안홍과 덕적도집단(average taxonomic distance, D=0.358)이 형태적으로 가장 유사한 집단으로 나타났다. Polyacrylamide gel을 사용하여 11가지의 동위효소를 검출한 결과 AKP, ACP, AO, EST, GPD, HBDH, LDH, SDH, XDH의 동위효소에서 유전적 다형현상이 나타났다. 전 집단의 평균 다형형의 빈도는 59.19%이며 이형접합자 빈도는 0.263이고 각 집단의 유전적 차이치는 춘천과 울릉도 집단이 0.066(genetic distance)으로 가장 높은 유사성을 보였다. 지리적 분포에 따른 외부형태 변이와 유전적 변이와의 관계는 유의성이 없었다.