• 천문학회보
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• 제43권1호
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• pp.44.3-45
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• 2018

Magnetic fields affect star formation in a broad range of scales from parsec to hundreds au. In particular, interferometric observations and ideal magneto-hydrodynamic (MHD) simulations have reported that formation of a rotation-supported disk at the earliest young stellar objects (YSOs) is largely suppressed by magnetic fields aligned to the rotational axis of YSOs: magnetic braking. Our recent ALMA observations toward L1448 IRS 2, which has a rotation detected and its magnetic fields aligned to the rotation axis (poloidal fields) in ~500 au scales, show that the fields switch to toroidal at the center in ~100 au scales. This result suggests that magnetic braking may not be so catastrophic for early disk formation even in YSOs with magnetic fields aligned to the rotational axis.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권2호
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• pp.89-96
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• 1999

This paper proposes a common-mode voltage reduction method base on SVPWM(Space-Vector Pulsewidth Modulation) in three phase PWM converter/inverter system. By shifting the active voltage vector of inverter and aligning this to the active vector of converter, it is possible to eliminate a common-mode voltage pulse in one control period. Since the proposed PWM method maintains the active voltage vector, it does not affect the control performance of PWM converter/inverter system. Without any extra hardware, overall common mode voltage dv/dt and conrresponding leakage current can be reduced to two-third of the conventional three phase symmetric SVPWM scheme.

• Journal of Astronomy and Space Sciences
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• 제37권2호
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• pp.95-104
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• 2020

Properties of plasmas that constitute the plasma sheet in the near-Earth magnetotail vary according to the solar wind conditions and location in the tail. In this case study, we present multi-spacecraft observations by Cluster that show a transition of plasma sheet from cold, dense to hot, tenuous state. The transition was associated with the passage of a spatial boundary that separates the plasma sheet into two regions with cold, dense and hot, tenuous plasmas. Ion phase space distributions show that the cold, dense ions have a Kappa distribution while the hot, tenuous ions have a Maxwellian distribution, implying that they have different origins or are produced by different thermalization processes. The transition boundary separated the plasma sheet in the dawn-dusk direction, and slowly moved toward the dawn flank. The hot, tenuous plasmas filled the central region while the cold, dense plasmas filled the outer region. The hot, tenuous plasmas were moving toward the Earth, pushing the cold, dense plasmas toward the flank. Different types of dynamical processes can be generated in each region, which can affect the development of geomagnetic activities.

• 한국농촌건축학회논문집
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• 제15권4호
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• pp.9-16
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• 2013

The purpose of this study is presented playground space for early childhood facilities. Describes whether any development of children, and how to respond in accordance with each of the activities. The infants and toddlers life cycle is a continuation of play. Toddlers to play is the essence of life itself, through play, the world embracing and digestive, raising ideas and emotions expressed through play. It is time that paves the growth of infants age children. And equipped with personality, values, emotions, attitudes, play a very important role in this process. Play it delivers, it can not learning education. Sympathetic and experience through play, and be equipped to allow the personality, social, physical. So, we have an obligation required to provide adequate facilities and play so that children can grow properly. In this paper, from the limited play space and is listed on the importance alive to give the children a sense of space to get the sympathetic. And, analysis shown about affect for children each play, and space. In this paper, we performed a study is Performed a case studies of and domestic kindergarten and foreign kindergarten where the differences between the various lists and how to derive a plan for solving the problem by comparison and analysis were performed.

• Journal of Astronomy and Space Sciences
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• 제37권1호
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• pp.1-9
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• 2020

Frozen orbit is an attractive option for orbital design owing to its characteristics (its argument of pericenter and eccentricity are kept constant on an average). Solar sails are attractive solutions for massive and expensive missions. However, the solar radiation pressure effect represents an additional force on the solar sail that may greatly affect its orbital behavior in the long run. Thus, this force must be included as a perturbation force in the dynamical model for more accuracy. This study shows the calculations of initial conditions for a lunar solar sail frozen orbit. The disturbing function of the problem was developed to include the lunar gravitational field that is characterized by uneven mass distribution, third body perturbation, and the effect of solar radiation. An averaging technique was used to reduce the dynamical problem to a long period system. Lagrange planetary equations were utilized to formulate the rate of change of the argument of pericenter and eccentricity. Using the reduced system, frozen orbits for the Moon sail orbiter were constructed. The resulting frozen orbits are shown by two 3Dsurface (semi-major, eccentricity, inclination) figures. To simplify the analysis, we showed inclination-eccentricity contours for different values of semi-major axis, argument of pericenter, and values of sail lightness number.

• 한국실내디자인학회논문집
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• 제20권4호
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• pp.46-53
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• 2011

Popular culture in modem society is that research is to understand the lives of the public. Since post-modem ism, in a clear perspective of the rapidly developing modern society, and the appearance of various societies have been drawn. Of the phenomenon is playing a large role in the admission of the public can see this was: strange places for the properties in the popular culture to analyze and find the meaning makes carry through their own perspective. It also dominates the field of spatial design for the public to understand cultural perspectives and positions should be aware of the importance of thinking. The relationship between spatial design and popular culture, modern society has become an essential point is changed popular culture that has more space, the design characteristics of the new changes will affect their position. In this study, playing a large role in the modern of culture properties, spatial design, looking at areas of social and cultural positions that are clearly focused. Therefore, the cultural phenomenon here in the popular culture of the design characteristics of the space, according to the visual design direction of modern society present in the space is presented.

• 한국주거학회논문집
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• 제22권3호
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• pp.15-24
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• 2011

The purpose of the research is analyzing how the emotional factors of the external apartment design can be influenced by the consumers' emotional reaction, and analyzing how the emotional reaction of the consumers will affect the expenditure of the apartment in the upcoming future. For this purpose, first, external surrounding factors of the apartment are extracted and then classified into three major design categories (instinctive, behavioral, and reflective design), and each factor is evaluated by the emotional evaluation. The scope of the research is restricted to the apartments in Daegu city which are built by Top 3 construction companies from the analysis of construction-working rank (May, 2010). The residential-expenditure data are extracted from D-univ. students, in accordance with the satisfaction of the external surroundings and emotional-reaction against the emotional-design factors of the apartment. This research is done by the statistic analysis program SPSS17.0. This shows that difference of emotional design by the apartment external space requisites will be significance as fundamental data for development of application and planning and apartment external space of emotional design by the apartment external space in the future.

• 한국실내디자인학회논문집
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• 제21권5호
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• pp.289-297
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• 2012

Recently the coffee industries rapidly grow as people's dietary life changes and quality of life improves. Proliferation of coffeehouses let people cognize them as cultural spaces not only mere spaces for drinking coffee beverages. Therefore, distinguished strategy for space design became the one of the most important factor for customers' decision-making. This study analysed the strategies for space design by the brands of coffeehouses, and focused on understanding how those strategies cognized by customers and how they affect customers' level of satisfaction and intention of revisitation. The result of analysis showed that the level of satisfaction was raised when customers cognized unique strategies by brands and the intention of revisitation was raised when the level of satisfaction and reflection of strategy were high. In other words, setting and applying unique strategies by brands are to raise up level of satisfaction and intention of revisitation. The result of study could be used for the basic data on designing coffeehouses attracting customers' revisitation. Also, it could be the basis for effective strategy for customers.

• Journal of Positioning, Navigation, and Timing
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• 제11권2호
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• pp.83-89
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• 2022

For precise GNSS applications, the antenna phase center correction (PCC) is absolutely required. The PCC magnitude can reach the centimeter level with the antenna structure. In the present study, we first investigate the phase center offset (PCO) and phase center variation (PCO) of three different antenna models in two different reference frames, IGS08/igs08.atx and IGS14/igs14.atx. Clear L1 and L2 PCO differences were found between IGS08 and IGS14. In addition, the PCV showed characteristics that is dependent upon the signal direction (azimuth and elevation angle). The remarkable thing is that the changes of a Dorne Margolin choke-ring antenna model (AOAD/MT DOME) was very small in two reference frames. In order to analyze changes in positions according to different reference systems, GNSS data obtained from DAEJ, SUWN, and TSKB stations were processed by the precise point positioning (PPP) method. We suggest that an antenna PCO/PCV can affect the precise GNSS positioning on the order of several millimeters in two different reference frames.

• 융합정보논문지
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• 제7권4호
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• pp.195-203
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• 2017

인터넷과 스마트폰 기반의 사회적 경제 활동의 일종으로, 물건이나 공간, 서비스를 빌리고 나눠 쓰는 공유경제는 융합 분야의 새로운 연구 주제이다. 가장 대표적인 공유경제 영역으로 공간 공유와 자동차 공유가 있다. 본 논문은 자동차 공유의도의 선행요인과 공유행동을 미치는 요인들을 파악하고자 한다. 본 논문에서는 선행연구에 바탕으로 공유의도와 관련된 경제적 혜택, 사회적 혜택, 사회적 영향, 심리적 혜택, 지각된 위험을 연구 변수로 도출하고, 이들이 공유의도에 어떤 영향을 끼치는지 연구하였다. 한국과 달리 중국은 자동차 공유가 법적으로 허용되고 많은 활성화 되어 있다. 가설을 검증을 위해서 중국 시민한테 설문지를 수거하였고, SPSS 프로그램으로 통계분석을 실시하였다. 분석결과 경제적, 심리적 혜택, 사회적 영향, 지각된 위험은 공유의도에 영향을 미치는 것으로 나타났지만, 사회적 혜택은 가설과 다르게 공유의도에 영향을 미치지 않았다. 또한, 공유의도가 공유행동에 영향을 미치는 것으로 나타났다.