• International Journal of Aeronautical and Space Sciences
• /
• 제18권4호
• /
• pp.662-674
• /
• 2017

This paper describes the multidisciplinary design optimization (MDO) process of a tailless unmanned combat aerial vehicle (UCAV) using global variable fidelity aerodynamic analysis. The developed tailless UAV design framework combines multiple disciplines that are based on low-fidelity and empirical analysis methods. An automated high-fidelity aerodynamic analysis is efficiently integrated into the MDO framework. Global variable fidelity modeling algorithm manages the use of the high-fidelity analysis to enhance the overall accuracy of the MDO by providing the initial sampling of the design space with iterative refinement of the approximation model in the neighborhood of the optimum solution. A design formulation was established considering a specific aerodynamic, stability and control design features of a tailless aircraft configuration with a UCAV specific mission profile. Design optimization problems with low-fidelity and variable fidelity analyses were successfully solved. The objective function improvement is 14.5% and 15.9% with low and variable fidelity optimization respectively. Results also indicate that low-fidelity analysis overestimates the value of lift-to-drag ratio by 3-5%, while the variable fidelity results are equal to the high-fidelity analysis results by algorithm definition.

• 한국농촌건축학회논문집
• /
• 제12권3호
• /
• pp.35-46
• /
• 2010

The purpose of this study is to interpretate the Korean traditional Private Garden Pavilion -'byoul-seo(別墅)' in the view point of the architectural methodology - the separation of space in Honam province. It is presumed that nature union is archived through the 'yan-sang(玩賞)' which is ultimate state of knowledge that is base on the premises of opened signification in emancipation from narrow view point in the past and cognition of value. therefore, it is needed to know the unworldly point of space perception about the pavilion territory, furthermore to have conceptual method to distinct pavilion from the world. there are two methods in the distinct concept in this pavilion research: unworldly separation and meditative separation. As a result, the followings are conclusions; There two distinctive methods of planning of pavilion by use of the room and column. There are enclosement, turnaround, division of floor area in the room organization method, and it's modification of modulation, diversification of column height and diversification of column use in different space.

• 천문학회보
• /
• 제42권1호
• /
• pp.57.2-57.2
• /
• 2017

Remote and robotic telescopes are the most effective instrument for astronomical survey projects. The system is based on the dynamic operation of all astronomical instruments such as dome and telescope control system (TCS), focuser, filter wheel and data taking camera. We adopt the ASCOM driver platform to control the instruments through the integrated software. It can convert different interface libraries from various manufacturers into a uniform standard library. This allows us to effectively control astronomical instruments without modifying codes. We suggest a conceptual design of software for automation of a small telescope such as the new wide-field 0.25m telescope at McDonald Observatory. It can also be applied to operation of multi-telescopes in future projects.

• 한국실내디자인학회논문집
• /
• 제24권2호
• /
• pp.67-77
• /
• 2015

This study is to contemplate an ultimate goal and new methodology the architecture and space design community should pursue forward by analyzing concepts in Kengo Kuma's idea of "Anti-object" and examining his design methods and characteristics. To this end, I reviewed space design methods and features in his book of "Anti-Object" and his architectures built around in 2000. The result is as in the followings. (1) Contact is an essential concept of "Anti-object" to connect and integrate divided materials and consciousness with time and space. (2) Elimination is a meaningful way to reverse "cohesiveness" of agglomerated cluster which is a form of object and reconstruct it into the form of passive and acceptive "Anti-object". This idea is realized through overlap of material property and removal of massing. (3) Minimization is a concept of "Anti-object" to set the temporality free from constraints of materials. Three-dimensional transparent faces and lines or patterns of porous materials can be used to remove static and coercive volume. (4) A particle is a "reflector of its environment." It rebuilds one-way or disconnected communication between human and architecture into an interactive one. Kengo Kuma materializes this "particle" by exploring positional relation with physical paths, precise details and measurements.

• 한국과학교육학회지
• /
• 제13권3호
• /
• pp.327-333
• /
• 1993

The purpose of this study was to investigate children's ideas about growth of plants and their conceptural change after instruction to apply SPACE (Science Processes And Concepts Exploration) Learning strategy. For this study, a total of 55 students from infants to 5th grade were sampled. Data were obtained by the individual interview procedure and summarized by using network analysis. The major results of this study were as follows : 1. A very small number of students responded reforming or reorganisation of materials about the mechanism of germination and growth inside the seeds. 2. Almost all students confused between conditions necessary for germination and growth. Water and sunlight were mentioned by many students, while air and temperature were mentioned by a few students as the condition. 3. Some of the students showed that growth occurs continuously. Many students explaned occurence of growth about Plants related to the night, monning, or evening. 4. With the explaning about the necessary conditions for caterpillar growth, students mentioned conditions related in terms of human experience. 5. Many young childrens showed tendency of the egocentric and human-centered view of the world. Students scientific concepts increased significantly with age. Many students conceptions depend on the context-specificity ideas.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2004년도 춘계 종합학술대회 논문집
• /
• pp.449-455
• /
• 2004

영상콘텐츠 디자인 분야에서 합리적이고 이성적인 미의 구현에 있어서 일반적으로 수행하고 있는 구체적인 실체가 있는 가시적 영역의 디자인에서 벗어나 탈물질화 시대의 가상 공간인 비가시적 영역의 연구를 통하여 가시적 디자인으로 구상해내고, 전자공간에서 만들어지는 영상그래픽 들의 내포 의미와 새로운 감각을 얻을 수 있는 계기를 마련하고자 한다. 특히 물질 사회에서는 전자기파와 같은 눈에 보이지 않는 현상은 공간에 실존함에도 불구하고 개념적인 대상으로 다루어지곤 했는데 이러한 기존의 제한된 관점에서 벗어나 비가시적인 영역에 대한 디자인의 물리적ㆍ시적ㆍ미학적 경험에 대한 디자인 방안을 모색하고자 한다. 이러한 이론적 근거로 프랙탈디자인 분야에서 사운드와 리듬, 칼라와 이미지의 적용으로 인한 새로운 디자인에 대한 가능성을 확보하고자 한다.

• 한국항공우주학회지
• /
• 제38권12호
• /
• pp.1209-1216
• /
• 2010

본 연구는, 위성에 장착되는 각종 전자장비 하우징을 종래의 알루미늄 합금에서 복합재료로 대체함으로써 위성 경량화를 극대화할 수 있는 대안을 다루었다. 이를 위해, 기존 전자장비 하우징 재료로 널리 사용되는 알루미늄 합금에 비해 가벼우면서, 충분한 내구성과 다양한 기능성을 제공하는 복합재료 전자장비 하우징 설계를 위한 요구사항을 정의하였다. 또한, 열전도도, 전기전도도, EMI 보호, 방사차폐 특성과 더불어 강도가 우수한 구조적 특성을 갖춘 경량 복합재료 전자장비 하우징을 모듈화 방식으로 제작하기 위한 개념설계를 수행하고, 위성설계에 있어 무게절감을 크게 향상할 수 있는 가능성을 제시하였다.

• Journal of Power Electronics
• /
• 제3권4호
• /
• pp.239-248
• /
• 2003

This paper presents a novel prototype of three-phase voltage source type zero voltage soft-switching inverter with the auxiliary resonant snubbers suitable for high-power applications with IGBT power module packages in order to reduce their switching power losses as well as electromagnetic conductive and radiative noises. A proposed single inductor-assisted resonant AC link snubber circuit topology as one of some auxiliary resonant commutation snubbers developed previously to achieve the zero voltage soft-switching (ZVS) for the three-phase voltage source type sinewave PWM inverter operating under the instantaneous space voltage vector modulation is originally demonstrated as compared with the other types of resonant AC link snubber circuit topologies. In addition to this, its operation principle and unique features are described in this paper. Furthermore, the practical basic operating performances of the new conceptual instantaneous space voltage vector modulation resonant AC link snubber-assisted three-phase voltage source type soft-switching PWM inverter using IGBT power module packages are evaluated and discussed on the basis of switching voltage and current waveforms, output line to line voltage quality, power loss analysis, actual power conversion efficiency and electromagnetic conductive and radiative noises from an experimental point of view, comparing with those of conventional three-phase voltage source hard-switching PWM inverter using IGBT power modules.

• 한국군사과학기술학회지
• /
• 제25권2호
• /
• pp.169-176
• /
• 2022

Laser ablation propulsion(LAP) is the method to create impulse by laser ablation. It can be used to deorbit the space debris(SD), as its long-range property and versatility on any material. In this paper, we find out several requirements of the LAP system(LAPS) to deorbit the SD by simple numerical calculations of the SD orbit and laser beam flux. As a result, minimum operable altitude angle turned out to be a crucial variable to the LAPS. Moreover, if minimum operable altitude angle is 10°, and if the minimum distance between the LAPS and the SD is below 450 km, 1 m/s² is sufficient to deorbit the SD by once. With 18 kJ/3 ns pulsed laser and cube shaped 100 kg SD, 1 m/s² acceleration can be achieved by increasing the pulse repetition rate over 34~53 Hz, depending on the size of the SD. This capability could compare with the conceptual design of the Japan Establishment for a Power-laser Community Harvest(J-EPoCH) facility, which include 8 kJ, 5 PW@100 Hz laser.

• Nuclear Engineering and Technology
• /
• 제54권3호
• /
• pp.888-895
• /
• 2022

Lately, ocean nuclear power plants have attracted attention as one of diverse uses of nuclear power plants. Because ocean nuclear power plants are movable or transportable, it is necessary to analyze the thermal hydraulics in a moving frame of reference, and computer codes have been developed to predict thermal hydraulics in large moving systems. The purpose of this study is to incorporate a three dimensional dynamic motion model into the SPACE code (Safety and Performance Analysis CodE) so that the code is able to analyze thermal hydraulics in an ocean nuclear power plant. A rotation system that describes three-dimensional rotations about an arbitrary axis was implemented, and modifications were made to the one-dimensional momentum equations to reflect the rectilinear and rotational acceleration effects. To demonstrate the code's ability to solve a problem utilizing a rotational frame of reference, code calculations were conducted on various conceptual problems in the two-dimensional and three-dimensional pipeline loops. In particular, the code results for the three-dimensional pipeline loop with a tilted rotation axis agreed well with the multi-dimensional CFD results.