• 전기학회논문지
• /
• 제57권3호
• /
• pp.403-408
• /
• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch. The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply (HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• 한국환경과학회지
• /
• 제9권6호
• /
• pp.443-447
• /
• 2000

Chonan and Asan city have been a focal point due to rapid development as the first station for Express Railroad and key cities West Coast Development Region. Gokgyo stream adjacent to the cities plays an important role as a drainage channel for an agriculture and a discharger of urban storm water. Waster quality of the stream has been deteriorating caused by pollution sources such as a untreated wastewater discharge and runoff from the watershed. In the study, we conducted 4 surveys in April, May, July, and September to understand the current state of water quality for the stream and to make it possibe to predict future water-quality variation for future development. The system runs on a personal computer under the windows enviroment and provides extensive graphic user interface(GUI) for user-friendly assessment. Using the pull-down menus provided by the GUI panel, the user is able to operate the system by pointing and clicking the icon to identify the state of water-quality at locations concerned. Furthermore, we developed an integrated watershed management system. The constructed system could be a useful tool as a decesion maker for pollution source control strategy.

• 복식문화연구
• /
• 제7권6호
• /
• pp.28-40
• /
• 1999

The purpose of this study was to understand the Korean teenagers\` clothing behavior through pointing out the factors that clothing behavior of teenagers that was initiated from the important reference group, TV stars. The subject of this study were 570 purposively selected students at female middle and high school students in Seoul. The results were as follows : 1. The clothing conformity to TV stars relating to demographic variables was influenced significantly by location and personal expense variable in the high school group. 2. The exhibition showed a more important role to the clothing conformity in middle school group than in high school group. 3. The clothing conformity to TV stars relating to the clothing related variables was significantly affected by self-confidence to clothing than clothing normative recognition, clothing risk recognition and degree of clothing importance regardless of groups. 4. The clothing conformity to TV stars relating to TV media variables was affected by TV media star identification variable in both groups. And in case of middle school group, interests in TV stars also had influence on the clothing conformity to TV stars. And in case of high school group, interests in TV had effect on the imitation to TV stars\` clothing. As middle school students tend to have self-identification about a particular person, TV media stars become the reference group for the adolescence to follow their clothing.

• 한국HCI학회:학술대회논문집
• /
• 한국HCI학회 2008년도 학술대회 1부
• /
• pp.456-460
• /
• 2008

`디지로그 북 (Digilog Book)' 은 아날로그 책과 디지털 콘텐츠의 장점을 통합함으로써, 아날로그적 감성과 디지털 오감을 함께 느끼도록 한다. 본 논문에서는 디지로그 북의 한 예로써, 범종 체험 시스템 구현에 관한 기술적인 사항을 언급한다. 시스템 구현은 사용자에게 다감각 피드백 (multisensory feedback) 을 제공, 책에 마커를 그림 마커로 대체하는 것, 책의 2D 평면에서 범종이 나올 의 효과, 범종 관찰을 위한 가상버튼을 손으로 누를 수 있도록 하는 부분, 감각형 객체를 이용하여 범종을 타종하는 것, 그리고 마지막으로 감각형 객체를 이용하여 범종의 특정 부분을 포인팅하여 특정 설명을 볼 수 있는 것을 포함한다. 본 논문에서 구현된 범종 체험 시스템은 사용자에게 우리나라의 문화유산을 체험해 볼 수 있는 교육적인 콘텐츠를 제공할 수 있다.

• 한국환경과학회지
• /
• 제13권2호
• /
• pp.117-127
• /
• 2004

The purpose of this study is to present the conditions and methods for keeping the sustainability of the landscape resources of the East Coast of Gangwon province, the Republic of Korea by investigating the landscape resources management in the area and pointing out its problems. The unit of analysis in this study is four cities and two counties located along the national road route seven in Gangwon province. The classification and characteristics of the landscape resources in this area was analyzed by a literature review, and we surveyed the tourists visiting the area and statistically analyzed the data in order to examine their satisfaction with the landscape resources management and make recommendations. The problems of the landscape resources management are: 1) the disturbance of the persistence of life by reclamation, the population reduction in the ecosystem due to the overload in environmental capacity, and the severance of space between land and water. 2) the reduction of the benefits from indirect experience by interfering with the conservation of fluxes --- the manipulation of horizontal arrangement of the landscape resource, the visual disturbance by the construction of high-storied buildings, and the disharmony between the color/image and the environment. The means for keeping sustainability of the landscape resources include the regulations of development and use, the change in the recognition of the value of landscape resources and the moral system, and the improvement of resource management skills.

• 항공우주산업기술동향
• /
• 제8권2호
• /
• pp.54-64
• /
• 2010

위성은 지상에서의 발사부터 우주에서의 운용까지 다양한 진동환경에 놓인다. 따라서 위성 설계시, 진동은 중요한 고려 대상중 하나이다. 경제적인 발사 비용을 위해 구조체 경량화는 필수적이며, 이는 진동측면에서 위성체내의 장비들에는 불리한 여건이 되고 있다. 또한 영상에 대한 해상도가 높아짐에 따라 탑재체의 지향 안정성의 보장을 위해 탑재체로 전달되는 하중에 대한 요구조건도 엄격해지고 있다. 이러한 상황을 해결하고자 진동절연 시스템이 도입되었으며, 발사체로 부터 전달되는 진동을 감소시키거나, 궤도상 운용중 위성내 장비들이 발생시키거나 이들로 전달되는 진동을 차단하는 방법이 적용된다. 본 논문에서는 진동저감과 관련된 최근의 위성체/발사체 적용 사례들을 살펴보고, 이를 통해 향후 진동절연 시스템 적용에 필요한 고려 사항들을 확인하고자 한다.

• 천문학회보
• /
• 제38권2호
• /
• pp.43.2-43.2
• /
• 2013

AGN are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. In the shortest time scale of AGN activity, unexplored territory still exists: first, the existence of a shortest time scale of AGN activity and secondly the shape of high frequency end of AGN power spectrum. Also the spectral variations at the shortest timescale. Here, we present the preliminary results of AGN fast photometry performed with Korean VLBI Network(KVN). Observations were done in a 'anti-correlated' mode using two antennas, with always either one antenna pointing at the target. This results in an effective time resolution of 3 minutes. We used all four KVN frequencies, 22, 43, 86, and 129 GHz, in order to trace spectral variability. We have been able to derive high-quality light curves for 3C111 and 3C279 at 22 and 86 GHz observed on 31st of May and 30th of Nov. in 2012. We are currently performing detailed statistical analysis in order to assess the levels of variability or the corresponding upper limits.

• Asian review of World Histories
• /
• 제4권1호
• /
• pp.35-81
• /
• 2016

The objective of this essay is to propose a cultural history of cosmography and cartography from the thirteenth to the sixteenth centuries. It focuses on some of the processes that characterized these fields of knowledge, using mainly western European sources. First, it elucidates the meaning that the term cosmography held during the period under consideration, and the scientific status that this composite field of knowledge enjoyed, pointing to the main processes that structured cosmography between the thirteenth century and the sixteenth century. I then move on to expound the circulation of cosmographic knowledge among Portugal, Venice and Lisbon in the fourteenth and fifteenth centuries. This analysis will show how cartography and cosmography were produced at the interface of articulated commercial, diplomatic and scholarly networks; finally, the last part of the essay focuses on the specific and quite distinctive use of cosmography in fifteenth-century European culture: the representation of "geo-political" projects on the world through the reformulation of the very concepts of sea and maritime networks. This last topic will be developed through the study of Fra Mauro's mid-fifteenth-century visionary project about changing the world connectivity through the linking of several maritime and fluvial networks in the Indian Ocean, Central Asia, and the Mediterranean Sea basin, involving the circumnavigation of Africa. This unprecedented project was based on a variety of sources accumulated in the Mediterranean Sea basin as well as in Asia and in the Indian Ocean over the course of several centuries.

• 대한수학교육학회지:학교수학
• /
• 제9권2호
• /
• pp.313-326
• /
• 2007

최근 대수 교육과정에서 패턴들을 표현하면서 일반적인 규칙을 인식하고 설명하는 것이 하나의 대안으로 제시되고 강조되고 있다. 우리나라 역시 제 7 차 교육과정에서 '규칙성과 함수' 영역과 관련하여 초등학교 과정에서 다양한 형태의 패턴활동을 지도하고 있다. 그러나 최근 패턴활동을 통한 학습에 대한 연구에서 학생들의 어려움과 문제점이 지적되고 있다. 이 글에서는 우리나라 초등학교 교육과정에 많이 도입되고 있는 시각적 패턴의 탐구 활동을 통한 일반화 과정을 중심으로 하여, 시각적 패턴의 일반화 과정에서의 다양한 접근과 학생들의 사고전략, 기호화 상태를 고찰한다. 그리고 시각적 패턴의 일반화, 기호화의 어려움을 논의하고 시각적 패턴의 탐구 활동 학습을 위한 몇 가지 제안을 하였다.

• 한국소음진동공학회논문집
• /
• 제21권9호
• /
• pp.828-833
• /
• 2011

A reaction wheel assembly(RWA) is the largest disturbance source that can induce high frequency micro-vibration on an optical payload of satellites. To ensure a tight pointing-stability budget of satellites, the RWA disturbance effect on spacecraft should be accurately analyzed and evaluated for whole design phases. For this purpose, the micro-vibration disturbance of RWA should be precisely measured. In the present study, two measurement methods on RWA micro-vibration disturbances are compared and investigated. One is a free run-down speed test and the other is a constant speed test. The micro-vibration data measured by the two methods are analyzed in terms of spectrum characteristics, static and dynamic imbalance values, and root sum square(RSS) values. The analysis results show that both methods can measure very similar results in time and frequency domains and that the free run-down speed method is more adequate in respects to wheel friction modeling, noise rejection of imbalance and RSS peak evaluation.