• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.175-184
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• 1994

RI photometric observations of an extreme long period eclipsing binary star AZ Cas have been made at the Yonsei University Observatory using the 60-cm Goto reflector for three seasons from 1990 to 1993. A total of 884 observations are made for 77 nights. All the data are standardized and determined the magnitudes and colors of AZ Cas. No significant light variation at the outside eclipse phase between $0.^p54$∼$0.^p87$. RI and color curves of AZ Cas are presented.

• Journal of Astronomy and Space Sciences
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• v.9 no.1
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• pp.30-40
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• 1992

The reflection effect on three types of eclipsing binaries has been analyzed based on the Wilson and Devinney's model and Russell and Merrill's model. The reflection effect was displayed on the theoretical light curves for the various conditions using the Wilson and Devinney's light curve program. Two models were compared after the rectifing the theoretical light curves including the reflection effect with the Russell and Merrill's method. The result shows that two models have an agreement on the reflection effect just in cases of the small difference in temperature adn albedo between two stars in the system.

• Journal of Astronomy and Space Sciences
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• v.10 no.1
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• pp.86-93
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• 1993

We experiment of the method to obtain the uniform gas multiplication in multiwire proportional counter. The general techenique of anode wire connection for the high voltage supply could not secure the uniformity of multiplication because of the edge effect at the outer anode wires. We found that the variation of the multiplication could be corrected in the accuracy of $\pm$1.6% rms using the voltage compansation method.

• 대한예방의학회:학술대회논문집
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• 2000.10a
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• pp.87-88
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• 2000

• 대한예방의학회:학술대회논문집
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• 2000.10a
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• pp.89-89
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• 2000

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.47-54
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• 2020

This study carries out a basic study of ways to calculate navigation errors for aircraft operating in the unmanned aerial system traffic management(UTM). Recently, research by UTM has been carried out both at home and abroad, along with the initial study of system definitions at the basic stage, operational techniques of the aircraft, and the practicality of the concept of necessary operations at the actual operational stage. This study presented after a review the factors that should be considered for the calculation of navigation errors among the factors that examine whether the actual low altitude aircraft can operate properly within UTM during its actual operation and the need to apply them in practice.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.33-41
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• 2020

The landing gear of an aircraft is a device that absorbs and dissipates shock energy transmitted from the ground to the fuselage. Among the landing gears, the semi-active MR damper landing gear is supposed to show high-shock absorption efficiency under various landing conditions and secure the stability when out of control. In the case of the MR damper landing gear using an annular channel rather than orifice, Amesim, a commercial multi-physics program, is considered as more useful than the conventional two-degree-of-freedom model because the damping force generated by the pressure drop through the flow annular path can cause cavitation in the low-pressure chamber of the MR damper with a specific internal structure. In this paper, the main dynamic characteristics of the MR damper landing gear with an annular type flow path structure has been analyzed under the condition of cavitation. Based on the analysis results using Amesim, a design guideline for the MR damper flow path that prevents cavitation has been proposed based on the modification of the arrangement of internal components of the damper. The guideline was verified through a drop simulation.

• Journal of the Daesoon Academy of Sciences
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• v.20
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• pp.223-272
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• 2009

Both Daesoon philosophy and Buddhist philosophy have strong aspirations for establishing a world comprised of human-beings. In other words, Daesoon philosophy and Buddhist philosophy put human-beings in the place of 'subject character(主語的 人格)' instead of 'predicate character(述語的 人格).' This is because a human is the master rather than a guest of the universe and the world. In this regard, it is safe to say that both Daesoon philosophy and Buddhist philosophy have a common goal of reaching 'an infinitely open life managed by a human-being, the master.' Daesoon philosophy and Buddhist philosophy also share the idea that everything in the universe is an organistic world that is closely connected, like a network. In this aspect, the two philosophies consider the whole world rather than the individual, and seek ways for people to live together actively while expanding the scope of community to the world. Even if 'the morality of living together (相生)' and 'the realization of mercy(同體大悲)' are completely different languages on the surface, it is not difficult to understand the homogeneity inherent in such expressions. Daesoon philosophy and Buddhist philosophy show endless reliability towards all humans and are declarative and reasonable, but both herald human beings as eligible to become the main characters of the future world and lead to the birth of independent human beings while inducing them to the highest position in the universe by liberating humans from the limitations they find. 'Heaven on Earth' as stated in Daesoon philosophy refers to an ideal society where humans and God harmonize, and God and humans complement each other. Also, the world will achieve political stability and equality, realizing an economically prosperous world. Furthermore, social justice will be realized and cultural and religious conflicts resolved. As humans acknowledge there is a way to live together in a universal nature, the environmental issue no longer becomes the top priority for human beings and a world where the morals of human beings reach the highest level will be established. From the original Buddhist perspective, King Jeonrhyun, the proxy of Buddha, realizes the ideal of Buddhism in the mundane world. The world controlled by King Jeonrhyun can be described as having liberty, equality, peace, justice, prosperity, morality, order, legality, democracy, welfare, etc. Therefore, the ideal Buddhist world is materially prosperous, physically healthy and socially just, as well as a world where moral maturity and mental freedom are achieved.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.5
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• pp.511-517
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• 2009

A servo type angle of attack sensor using the null-seeking method is designed and its characteristics are analyzed in this study. Angle-of-attack in the null-seeking method is given by the probe rotation angle with respect to the body reference line when pressure difference measured in two holes on the probe becomes zero. This method provides highly accurate and uniform angle-of-attack measurements over all range. Hence, this kind of angle-of-attack sensor is adequate for unmanned aerial vehicles(UAVs). In this paper, we first analyze the requirements for developing angle-of-attack sensors. And the servo type angle-of-attack sensor is then designed and fabricated. The on-board angle-of-attack calculation algorithm is also developed. Finally, the characteristics of the developed angle-of-attack sensor are identified through MATLAB Simulink and wind tunnel tests.

• Spatial Information Research
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• v.8 no.2
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• pp.183-189
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• 2000

According to Oriental perspective on Universe, all systems become complete when three elements namely time, space, and human are all present. The only computer technology which can integrate these three elements is GIS. The current GIS database and system architecture, however, mainly concentrate on managing and analyzing spatial data without considering temporal and human elements. Despite the limitations, it is certain that GIS technology will develop into a unity within which the three elements of time, space and human are integrated. On the other hand, with the rapid acceptance of Internet technology, a new small universe that can be called "cyber world" is emerging. However, the current small univers created by internet is only a half-universe which does not include the concept of space. The creation of "cyber nation" which truly reflects our living environment in computer and information communication networks can only be achievedthrough the integration of GIS and Internet. Currently, many countries are heavily investing in GIS. Based on the magnitude of investments, we can expect that the concept of "cyber nation" will further develop into "cyber world" where the search for information on any part of global village is possible with the simple use of mobile phone regardless of time or location. If so, it might be possible to create a "Digitopia", a digital utopia in cyber space. A new world is opening by the integration of GIS and Internet.is opening by the integration of GIS and Internet.