• 한국항공운항학회지
• /
• 제26권4호
• /
• pp.122-128
• /
• 2018

A compound drone that combines a fixed wing and a rotary wing is an aircraft that can take off and landing vertically, and can increase flight time and fly faster with fixed wings. The compound drones are divided into many types depending on the method of adding the thrust vectoring or the lift fan and the position of the rotor. In this study, we designed and fabricated a composite drone with four V-TOL motors in a fixed-wing, and assigned missions to the aviation body, hence judged mission accuracy using the actual flight test. The design process and the mission evaluation process employed in this study can be utilized on the development of various unmanned aerial vehicle.

• International Journal of Aeronautical and Space Sciences
• /
• 제16권4호
• /
• pp.602-613
• /
• 2015

As one of the mission payloads to be verified through the cube satellite mission of Cube Laboratory for Space Technology Experimental Project (STEP Cube Lab), we developed a hinge driving separation nut-type holding and releasing mechanism. The mechanism offers advantages, such as a large holding capacity and negligible induced shock, although its activation principle is based on a nylon cable cutting mechanism triggered by a nichrome burn wire generally used for cube satellite applications for the purpose of holding and releasing onboard appendages owing to its simplicity and low cost. The basic characteristics of the mechanism have been measured through a release function test, static load test under qualification temperature limits, and shock measurement test. In addition, the structural safety and operational functionality of the mechanism module under launch and on-orbit environments have been successfully demonstrated through a vibration test and thermal vacuum test.

• 건축역사연구
• /
• 제13권2호
• /
• pp.57-70
• /
• 2004

Since Korea disclaimed to open the ports, Korean architecture has met the impetuous transformation. Although there would be various factors of this transformation, the new-coming architecture by missionary seemed to be a significant one, and many researches have been carried out on this theme in diverse viewpoints. However, because these researches have preponderated on the Catholic tradition, it is deficient for clarify the whole history of mission architecture. Therefore, this research has the meaning to enrich the history of Korean modern architecture by making balance. First of all, this paper is focused on the activities of one missionary, Graham Lee. He is a practical missionary at the beginning, his architecture made a critical influence in Korean traditional architecture. Graham Lee was born in Rock Island, Illinois, 1861, and he determined to become a missionary through grown up. He spent his boyhood by working as a plumber for his purpose and studied in a university afterward. Graduating of McComick Theological Seminary, he was nominated as a pioneer of Pyeng Yang Mission Station and set foot in Korea, September of 1892. Since then he started to erect missionary facilities in Pyeng Yang, such as Well House(1898), Pyeng Yang Central Church(1900-1901), Pyeng Yang Academy(1902). These all his works are designed with eclectic style which shows western and Korean traditional style intermingled. This unique characteristic made a profound influence to the Korean mission architecture afterwards. Especially, the L-type plan of Pyeng Yang Central Church, which is first shown by him, is recognized very unique, and this plan type had been spread all over the country. Therefore the L-type plan became the peculiar feature of the early Korean churches. Furthermore, working with Korean carpenters, he taught them new skills of modem buildings. After that, they were expanded out northern part of Korea and took the roles of master builders. According to this expansion, his particular style had got spread and had been settled as a unique eclectic style in Korean modern architecture. In the conclusion, he is evaluated to be a critical pioneer missionary, who left a big influence on the frame work of Korean modern architecture in the transitional times.

• Journal of Astronomy and Space Sciences
• /
• 제19권3호
• /
• pp.197-206
• /
• 2002

NORAD Two Line Elements (TLE) are widely used for the increasing number of small satellite mission operations and analysis. However, due to the irregular periodicity of generation of the NORAD TLE, a new TLE that is independent of NORAD is required. A TLE type Orbit Determination (TLEOD) has been developed for the generation of a new TLE. Thus, the TLEOD system can provide an Antenna Control Unit (ACU) with the orbit determination result in the type of a TLE, which provides a simple interface for the commercialized ACU system. For the TLEOD system, NORAD SGP4 was used to make a new orbit determination system. In addition, a least squares method was implemented for the TLEOD system with the GPS navigation solutions of the KOMPSAT-1. Considering both the Orbit Propagation (OP) difference and the tendency of $B^{*}$ value, the preferable span of the day in the observation data was selected to be 3 days. Through the OD with 3 days observation data, the OP difference was derived and compared with that of Mission Analysis and Planning (MAPS) for the KOMPSAT-1. It has the extent from 2 km after sit days to 4 km after seven days. This is qualified enough for the efficiency of an ACU in image reception and processing center of the KOMPSAT-2.

• 한국전자파학회논문지
• /
• 제12권3호
• /
• pp.339-345
• /
• 2001

본 논문에서는 FG-CPW (Finite-Ground Coplanar Wave-Guide) 구조의 평형 다이오드 혼합기에 대해서 논의 된다. 주파수 대역 C-band로 선택하였고, RF는 5.72~5.82GHz, LO는 5.58~5.68GHz, 그리고 If 신호는 140 MHz가 사용되며, 이와 동일한 조건에서 마이크로스트립 혼합기를 제작하여 그 특성들을 비교하여 C-band 대역에서의 FG-CPW 의 응용 가능성을 제시한다. 단일 평형 형태를 위해 rat-race 결합기가 이용된다. CPW 구조를 갖는 LPF(low pass filter) 가 우수한 변환 손실 특성과 불필요한 하모닉들의 억제를 위해 사용된다. 5.635 GHz에서 4 dBm의 출력을 갖는 LO 신호가 입력될 때 6.2dB의 혼합기 변환 손실을 얻는다. 또한, LO-RF 격리특성과 LO-IF 격리 특성은 각각 30 dB와 40dB의 특성을 얻는다. 제시된 혼합기는 무선 LAN 분야에 응용될 수 있으리가 기대된다.

• 문화기술의 융합
• /
• 제9권5호
• /
• pp.409-413
• /
• 2023

오늘날 군은 조직구성원의 특성변화에 맞추어 조직 효과성을 달성하기 위해 많은 노력을 하고 있다. 현재 한국군에서 행동으로 움직이는 여단급 이하 조직구성원은 우리가 흔히 이야기하는 MZ세대가 주축을 이루고 있다. 이와 같은 MZ세대는 개인의 만족과 가치관을 중요시하는 특성으로 타인이 자신의 취향과 의견을 인정해 주지 않으면 공정하지 않다고 생각한다. 따라서 군에서도 이와 같은 조직구성원들의 특성에 맞추어 다양한 지휘 방법과 조직문화를 개선할 필요가 있다. 본 연구에서는 군사 선진국인 독일군의 임무형 지휘의 특성 및 핵심요소를 분석하였으며 이러한 독일군의 사례를 고찰하여 우리나라 군 조직의 주축인 MZ세대의 관점에서 군 조직 실정에 맞는 '임무형 지휘' 시스템을 도입해야 할 것이다.

• 한국콘텐츠학회논문지
• /
• 제17권2호
• /
• pp.337-348
• /
• 2017

육군은 1999년 임무형 지휘를 육군의 지휘개념으로 전 부대에 정착시키고자 하였으나 아직까지 정착되지 못한 상태이다. 그 이유 중 하나가 임무형 지휘에 대한 실천적 방안의 부재를 들 수 있다. 따라서 임무형 지휘는 변혁적 리더십과 유사한 개념으로 변혁적 리더십의 하위요인이 조직효과성에 미치는 영향에서 개인의 인지사고 특성이 어떻게 조절되는지 확인하고자 했다. 본 연구의 주요결과는 다음과 같다. 경로분석에 대한 <가설 1>검증결과는 변혁적 리더십의 하위요인인 카리스마와 개별적 배려가 직무만족에 긍정적(+)인 영향을 미치고, 카리스마가 조직몰입에 긍정적(+)인 영향을 미치는 것으로 나타났다. 그러나 개별적 배려와 분발고취가 조직몰입에 통계적으로 유의한 영향력을 미치지 못하여 <가설 1>은 부분 채택되었다. <가설 2> 조절효과 검증에서는 개인의 각 인지처리특성의 높고, 낮음의 차이에 따라 변혁적 리더십이 조직효과성에 미치는 영향력에 차이가 있는 것으로 나타났다. 이상의 결과들은 다음과 같은 시사점을 제시한다. 첫째, 군 조직은 상명하복을 중요시하는 특수한 집단으로 상급자의 카리스마는 조직효과성에 큰 영향을 준다는 것이다. 둘째, 육군에서 임무형 지휘가 정착하기 위해서는 본 연구를 토대로 임무형 지휘의 하위요소를 탐색하고, 임무형 지휘를 적용함에 있어서는 개인의 특성을 고려하여 적용할 필요가 있다는 것이다.

• 천문학회보
• /
• 제39권2호
• /
• pp.110.1-110.1
• /
• 2014

The optics of Space telescope is one of the major parts of space mission used for imaging observation of astronomical targets and the Earth. These kinds of space mission have a bulky and complex opto-mechanics with a long optical tube, but there are attempts have been made to observe a target with a small satellite in many ways. In this paper, we describe an optical design of a reflecting telescope for use in a CubeSat mission. For this design, we adopt the off-axis segmented method of astronomical observation techniques based on the Ritchey-Chr$\acute{e}$tien type telescope. The primary mirror shape is a rectangle with dimensions of $8cm{\times}8cm$, and a secondary mirror has dimensions of $2.4cm{\times}4.1cm$. The focal ratio is 3 which can obtain a $0.3{\times}0.2$ degree diagonal angle in a $1280{\times}800$ CMOS color image sensor with a pixel size of $3{\mu}m{\times}3{\mu}m$. This optical design can capture a ${\sim}4km{\times}{\sim}2.3km$ area of the earth's surface at 700 km altitude operation. Based on this conceptual design, we will keep trying to study more for astronomical observation with Attitude control system.

• Journal of the Optical Society of Korea
• /
• 제17권6호
• /
• pp.533-537
• /
• 2013

Space telescope optics is one of the major parts of any space mission used to observe astronomical targets or the Earth. This kind of space mission typically involves bulky and complex opto-mechanics with a long optical tube, but attempts have been made to observe a target with a small satellite. In this paper, we describe the optical design of a reflecting telescope for use in a CubeSat mission. For this design we adopt the off-axis segmented method for astronomical observation techniques based on a Ritchey-Chr$\acute{e}$tien type telescope. The primary mirror shape is a rectangle with dimensions of $8cm{\times}8cm$, and the secondary mirror has dimensions of $2.4cm{\times}4.1cm$. The focal ratio is 3 which can yield a 0.383 degree diagonal angle in a $1280{\times}800$ CMOS color image sensor with a pixel size of $3{\mu}m{\times}3{\mu}m$. This optical design can capture a ${\sim}4km{\times}{\sim}2.3km$ area of the earth's surface at 700 km altitude operation.

• 천문학회보
• /
• 제46권1호
• /
• pp.43.4-44
• /
• 2021

99942 Apophis is an Sq-type Aten group Near-Earth Asteroid (NEA) with an estimated size of 370 m. It will approach the Earth to come within the geostationary orbit during the upcoming encounter on April 13, 2029 to offer a unique chance to study its 1) global properties, 2) surface arrangements, and 3) their detectable changes expected to happen, in sub-meter scale. What measurable scientific goals for the asteroid in this "once a millennium" event could transform our knowledge of planetary science and defense? The Apophis rendezvous mission aims to understand the characteristics of the small solar system body's nature. It also prepares for potential threats from natural objects by measuring in-situ surface, shape, rotation, and orbit changes expected to occur when the target asteroid passes close to the Earth in 2029. We will present an overview of the mission scheduled to be launched from late 2026 to early 2027 and introduce scientific objectives.