• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.10
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• pp.1017-1025
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• 2008

The air data system(ADS) was developed for unmanned aerial vehicle(UAV) in this paper. Generally, the ADS helps flight control computer(FCC) to control the UAV above the stall speed and to hold the given altitude. The accurate measurement of airspeed and altitude of UAV is important because it indicates a flight performance and assures a safe flight. The ADS consists of MEMS pressure sensors, a lowpass filter, a micro controller unit and a pitot-tube. The ADS errors were reduced by pressure and temperature compensation of MEMS sensors. Finally, the altitude and airspeed data of the ADS was compared with GPS data in the flight test.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.205-212
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• 2006

Atmospheric drag is the most significant factor effecting the low Earth satellites under the altitude of 800 km Although the atmospheric density of the low Earth orbit is very low compared to that of the sea level, the accumulated effect of the atmospheric drag slowly lowers the satellite velocity at the perigee. Decrease in velocity at perigee directly causes decrease in altitude at apogee which changes the eccentricity of the orbit. The orbit finally reaches a circular orbit before reentering the Earth. This paper states the methods of calculating the atmospheric drag and the lifetime of the satellite. The lifetime of the kick motor and the satellites which will be used on KSLV-L are calculated by Satellite Tool Kit.

• Journal of the Korea Computer Industry Society
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• v.6 no.2
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• pp.259-264
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• 2005

This paper have derived an expression(the fringe modle is used) for the photocurrelation-correlation function for a cross-beam laser velocimeter, taking into account the effects of atmospheric turbulence on the amplitude and phase of the incident beams. the result, as long as the atmospheric disturbances do not greatly damp out sinusoidal variations of the photocurrent-correlation function in the time it takes a particle to travel the fringe-separation distance, the disturbances do not hinder the determination of the velocity of the partides from the correlation funtion.(the scattering particles are assumed to have a well-defined V).

• Defense and Technology
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• no.7 s.245
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• pp.38-47
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• 1999

대기의 상태는 지역, 시간, 기상 조건 등에 따라 변하므로 고도를 계산하는데는 북반구 중위도 지방에서 관측된 기상자료 등을 기준으로 제정한 표준대기를 적용한다. 속도를 계산하는데 전압과 정압의 압력차로 정의하는 항공기용 대기속도계 차압표를 사용한다. 계산된 에어 데이터는 비행계기나 cockpit display에 표시되어 조종사에게 정보로 전달됨과 동시에 자동조종 장치, 관성항법 장치, 비행관리 시스템, 항공관리 트랜스폰더 등에 기초 자료로 공급된다

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.213-214
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• 2001

대기오염 물질은 건성침착과 습성침착의 두 가지 과정에 의해 지표로 침착된다. 습성침착은 구름과 강수과정에 의해 지표로의 침착을 의미하며 건성침착은 오염물질이 직접 지표면에 침착되는 현상을 일컫는다. 본 연구에서는 경기도 이천시 설성면의 16 m 높이의 관측탑에 세 고도에서 관측된 농도 자료와 기상자료를 사용하여 경도법으로 SO$_2$의 건성침착속도를 산출하고 이의 안정도에 따른 특성을 분석하고자 한다. (중략)

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.203-211
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• 2019

The two key factors controlling the atmospheric general circulation are the equator-to-pole temperature difference and the Coriolis force driven by Earth's rotation. Although the former's role has been extensively examined, little has been reported about the latter's effect. To better understand the atmospheric general circulation, this study investigates the responses of Hadley Cell (HC) and westerly jet to the rotation faster or slower than the present Earth's rotation rate. It turns out that the HC edge and jet position tend to move equatorward and become weaker with increasing rotation rate. In most cases, the HC edge is quasi-linearly related with the jet position except for the extremely slow or fast rotating cases. The HC edge is more inversely proportional to the root of rotation rate than the rotation rate in the range of 1/8 to 8 times of the current Earth's rotation rate. However, such a relationship does not appear in the relationship between HC strength and jet intensity. This result highlights that while the latitudinal structure of atmospheric general circulation can be, to some extent, scaled with the Earth's rotation rate, overall intensity cannot be simply explained by the Earth's rotation rate.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.85-86
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1998.10a
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• pp.257-258
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• 1998

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.145-151
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• 2009

Current highway design standards is based on the safety under the free flow condition. The length of deceleration lane is also determined in terms of the deceleration distance which is necessary for the driers to adjust the vehicle speed from the speed limit on the main road to that on the exit ramp of the interchange. However, the queues are frequently developed on the deceleration, and the following vehicles to exit must decelerate on the main road. It may cause delay on the main road and traffic accidents. This study is to suggest a methodology to minimize such problems with the shock-wave theory. The queue length of exiting vehicles can be estimated by the design speeds, traffic volumes of main road and the exiting ramp, and the countermeasures to the operational problems. According to the results, the queue length can be shortened to 80% by upgrading the design speed of exit ramp as the amount of 10km/h. Fifty percent of queue length can be shortened by adding an additional lane on the ramp to two lanes.

• 전기의세계
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• v.34 no.10
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• pp.620-625
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• 1985

고도측정정도에 대하여 실제운용상태의 측정출력데이터는 차량의 진속도에 대해 10% 이내로 생각하면 차이가 없다. 또한 환경조건중 바람의 영향은 전술한바와 같이 풍속 10m/s에서는 30km/h인 경우 0.17%, 100km/j인경우 0.32% 또한 풍속 25m/s에서는 30km/h인경우 0.7%, 100km/h인경우 1.1%정도하는 것이 이론적으로 구해진다. 한편 기온의 영향도 원리적으로 초음파의 전번속도가 대기온의 영향을 받아서 오차요인이 되기 때문에 초음파헤드내에 온도센서를 실구해서 대기온을 거상측정하고 이 값으로서 속도연산을 포상하는 수단을 취하고 있다.