• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.391-396
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• 2004

Spaceborne earth observation or astronomical payloads often use Cassegrain-type telescopes due to the limits in mass and volume. Precision optical alignment of such a telescope is vital to the success of the mission. This paper describes the simulated optical alignment methods using interferograms, wavefront error, and reverse-optimization method for different levels of alignment accuracy. It concludes with the alignment experiment results of a Cassegrain type spaceborne camera with 300mm entrance pupil diameter.

• Journal of the Korean Society for Library and Information Science
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• v.39 no.2
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• pp.57-84
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• 2005

The standards for instructional media and equipments imply an essential element for curriculum. In knowledge-based society, school libraries are an educational environment to assist curriculum, offer information literacy and reading services. Therefore the standards for school libraries instructional media and equipments are able to suggest the mission of school library media center, and it should contain suitable elements for educational roles. But the current standards are insufficient from quantitatively as well as qualitatively. So the standards, if standards for instructional media and equipments are revised, should be contain following contents. 1. facilities guidelines: 2. basic equipment plan; 3. instructional media for educational roles; 4. equipments for each essential. area space: 5. more detailed information appliances; 6. improvement of standard for special school library

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.62.2-62.2
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• 2013

It is considered that comets near the ecliptic plane have been injected into inner solar system from Kuiper-belt. Some of them are still active while others are dormant with no detectable tails and comae. These dormant comets have eccentric and/or inclined orbits, which are parameterized by Tisserand parameter TJ<3. In addition, dormant comets can be differentiated from asteroids based on the albedo, because they have low albedo (the geometrical albedos pv<0.1). The conditions of TJ<3 and pv<0.1 have been used as a criteria to discriminate dormant comets from asteroids. However, we must be more careful because there are 'contaminations' from the outer region, i.e. Jovian Trojans (5.05

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.1
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• pp.27-32
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• 2014

In this study, active and recently in the field of vocational rehabilitation of persons with disabilities in the industry engaged in the primary mission of assisting you want to promote activation of devices that can perform the work of the harvest cart or unattended devices such as tool boxes and tracking system developed. This system is manually moved from a remote user is able to control, and also, the ability to track users unattended mounted. The system developed in this study in the field of vocational rehabilitation in order to allow all sides to assess more than three meters in open space system for the Y-and W-course driving range of the error from the final destination 5 times the period analyzed. Analysis of the user's tracking system developed without any problem and that could know.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.67-67
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• 2012

Exploring the distant universe by observing various astronomical objects and extending knowledge on the cosmos by applying human intuition and reasoning to observations are astronomers' professional activity. Astronomers are the people born under a lucky star since this elegant and beautiful job is their the only duty. Being in the 21st century we astronomers now know that galaxies are holding evolving stars and gas, and distribute in the infinite spacetime in an interesting way revealing the secrets of the beginning of the universe. Cosmic structures such as galaxies, large-scale structures, and cosmic microwave background fluctuations are also the tracers of the expansion of space and the invisible components of the energy contents of the universe. Unlike the past century we are in a situation where integral knowledge on various cosmic structures as well as that on a variety of observational and analysis tools are available to everyone and often required for our special mission. However, my experience made me think that accumulating critical questions on nature driven by curiosity is vital for researchers and far more important than absorbing knowledge from others and books. Transforming one's own question marks to acclamation marks is the reward of our life. That is THE fun.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.167.2-167.2
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• 2012

경희대학교와 UC Berkeley, Imperial College London에서 공동으로 진행하는 TRIO-CINEMA Mission(TRiplet Ionosphere Observatory-Cubesat for Ion, Neutral, Electron and MAgnetic fields)은 총 3기의 초소형 위성으로 구성되어 있다. 3기의 위성은 고도 650~800km 상공의 태양동주기 궤도운동을 예상하고 있으며, 지구 근접공간의 입자 검출과 자기장 측정의 과학 임무를 맡게 된다. TRIO-CINEMA 비행 모델(Flight Model)의 환경시험은 진동시험과 열진공시험으로 진행되었다. 진동시험은 X, Y, Z 세 축에 대해 Sine 과 Random 모드로 진행되었다. TRIO-CINEMA가 탑재 될 러시아의 드네프르 로켓의 요구사항은 각 축에서 20Hz 이상의 고유진동수, Sine의 경우 최대 0.8G와 4oct/min Sweep Rate, Random의 경우 5.2Grms 와 35초의 지속시간에서의 안정성을 만족하는 것이다. 시험 결과 TRIO-CINEMA가 요구사항을 모두 만족시키는 것을 확인하였다. 또한, 열 주기 시험(Thermal Cycling Test)을 진행하여 우주공간에서 위성 시스템이 정상 동작하는지에 대한 신뢰성을 검증하였다. 열주기 시험은 미국 MIL표준 값을 참고하여 $10^{-6}Torr$에서 $-20{\sim}30^{\circ}C$의 온도를 주었으며, 시험을 진행하는 동안과 시험 후에 위성이 정상작동 함을 확인하였다. 이에 본 연구의 시험 방법과 그 결과를 기술하였다.

• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.130-138
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• 2011

A vent relief valve performs as a safety valve, which ensures ventilation of propellant tank during filling and protection from tank overpressure after filling. Because of the reliability and cost saving, the virtually same vent relief valve has been used on all US cryogenic liquid fueled launch vehicles. Some modification to the valve has been applied to satisfy the various mission requirements of launch vehicles. This paper reviews the main technology trends of the vent relief valve applied to the propellant feed system for launch vehicle with respect to design and manufacture. This paper also introduces the operating technology of vent relief valve applied for launch vehicles of advanced countries in space development.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.343-348
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• 2010

Recently, unmanned electric vehicles are increasingly interested among all of the world since they can provide low exhaust gas, high efficiency and high mobility. To exploit their silent maneuver and high mobility, unmanned electric vehicles have been developed since early 1980's for military. However, it is not easy to design and control a power system satisfying operating duration and mobility performance requirements based on various mission profiles for military use under the conditions of limited space and weight. Moreover it is also necessary to prevent over-charge, over-discharge and voltage unbalance between cells of battery to secure high voltage battery which is serially connected with muti-cells. In this paper, we presents power control and optimal management method for the dog-horse robot which adopts a electric power system and suggests a guide-line to manage and control to secure high voltage battery.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.82-88
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• 2004

To evaluate the tidal flow around the transmission type harbour structures, the numerical models considering hydraulic resistance are used. The traditional governing equations of depth-integratef hydrodynamics are modified by using of the drag force term. As a numerical model to evaluate the rate of tidal exchange, the Random-walk method is used. The models are applied in a design of the pile-supported pier structures in Busan harbour site, Korea, where the flow speed and the tidal exchange are more promotive than the case of non-transmission structure. The developed model will be applied usefully to design the transmission type structure in the ocean space.

• Korean Institute of Interior Design Journal
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• no.32
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• pp.72-81
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• 2002

Southeast Asian region cruise market is expected to be stable or grow in the near future depending on the region's economy. Star Cruises company, which has entirely dominated the regional market since 1998, has attempted to expand beyond traditional cruise routes in Southeast Asian region and develop new markets in Thailand and Dubai. Such a situation urges Korean shipyards to study on Southeast Asian region based cruise ships. This study is to suggest directions for planning of interior spaces of Southeast Asian region based cruise ships. In order to accomplish this purpose the market situation is analyzed and the adequate ship's tonnage(70,000grt class) is decided. According to mission-based design process the sizes of standard staterooms are set up first and then the sizes of the important structural parts of ship are calculated. Through analyzing the 26 cruise ships of 70,000grt class the kinds, locations and sizes of public rooms are grasped. And we inspect 4 cruise ships of Star Cruises, which are now being operated in Southeast Asian region to understand design characteristics of interior spaces.