• 대한전자공학회논문지TE
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• 제37권1호
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• pp.12-17
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• 2000

본 논문은 가스의 방전 현상으로부터 발생되는 자외선을 이용하는 평판 형광 램프의 주파수 특성에 대하여 연구하였다. 램프는 절연층, 형광층, 가스층으로 구성된다. 램프의 특성에서 불꽃 전압과 휘도 균일 전압은 주파수의 증가에 따라 감소하였다. 이것은 가스 갭내에서의 공간 전하 효과로 설명이 가능하였다. FFL의 휘도는 700Vrms, 80 kHz의 구동 조건에서 2700cd/$m^2$ 을 얻었으며, 최대 휘도 효율은 5 lm/W를 보였다.

• 설비공학논문집
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• 제22권9호
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• pp.614-619
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• 2010

Recently, a problem related to the thermal management in portable electronic and telecommunication devices is becoming issued. That is due to the trend of a slimness of the devices, so it is not easy to find the optimal thermal management solution for the devices. From now on, a pressed circular type cooling device has been mainly used, however the cooling device with thin thickness is becoming needed by the inner space constraint of the applications. In the present study, the silicon flat plate type cooling device with the separated vapor and liquid flow path was designed and fabricated. The normal isothermal characteristics created by vapor-liquid phase change was confirmed through the experimental study. The cooling device with 70 mm of total length showed 6.8 W of the heat transfer rate within the range of $4{\sim}5^{\circ}C/W$ of thermal resistance. In the future, it will be possible to develop the commercialized cooling device by revising the fabrication process and enhancing the thermal performance of the silicon and glass cooling device.

• 교육녹색환경연구
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• 제13권1호
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• pp.75-85
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• 2014

In this study, the characteristics and the composition of the school groundrevels in Korea to identify the problem, were compared with Japan, where in geographic and culturally similar environment the composition of the school groundrevels analyzed. The spatial extent of this study is the development of metropolitan areas and small city within 10 years (range time) survey of the 34 elementary schools were analyzed. The results are as follows: First, the school groundrevels are flat step-like form of the composition for the same level of barrier-free should be provided. Second, if the lower places in slopes where to place buildings and playgrounds are placed in high places. Third, the external space and the interior space of the connection is the concept of fault tolerance and eliminate need for stairs. This study is a part of the urban Newtown and there are limitations to generalize the results. Therefore, this result on the general guidance of school groundrevel composition in order to objectify an additional studies are required.

• 천문학회보
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• 제40권2호
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• pp.42.1-42.1
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• 2015

We model the Spectral Energy Distribution (SED) of Class 0 protostar L1527 IRS using a radiative transfer code RADMC-3D. In addition to the photometry data from literatures, we include the Herschel/PACS data which well covers the far-infrared SED peak of L1527 IRS, providing precise constraints to the density structure and other physical properties of its circumstellar envelope. Previously, Tobin et al. (2013) presented a dust continuum modeling results using a rotating and infalling envelope (Terebey and Shu, & Cassen 1984 ; TSC envelope), which originally describes a power-law density profile (${\rho}{\propto}r-{\alpha}$) with the power-law index (${\alpha}$) of 1.5. However, we find that Herschel/PACS data are better fitted with a shallower power-law density profile. This smaller power-law might be attributed to a inner envelope. Thus, we fit the SED of L1527 IRS with a Bonnor-Ebert sphere, which is a combination of the inner flat-topped and the outer power-law (${\alpha}=2$) density profiles. This Bonnor-Ebert sphere is often used to explain the density profile of prestellar cores, which is considered the earliest stages of star formation. The well-fitted SED with a Bonnor-Ebert sphere suggests that L1527 IRS might have collapsed from a Bonnor-Ebert sphere rather than a singular isothermal sphere.

• 한국의류학회지
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• 제33권8호
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• pp.1253-1261
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• 2009

The paper-folding effect of origami signifies a planarization of the body which questions the three dimensional construction of the body in a more conventional clothing system. Un-structured, variable space posited between the body and clothes, and an absence of gender identification characterizes the planarization of the body. Origami inspiration in fashion stresses a will-to-form rather than mere bodily proportion and structure, which explores a trans-extensity that goes beyond the boundary of the body. This study inquires on the influence of origami as a method to create new vestmental space in contemporary fashion. The flat-plane clothes of origami-inspired design are no longer cut to the body and the clothes could be altered by the wearer. The space is introduced in between a three-dimensional dress-body and the body. Origami-inspired design in Japanese avant-garde fashion deconstructs the convention and promotes a symbiosis of body and clothing instead. The shape of the body is completely estranged by three-dimensional sculptures, alluding to the paper folds of origami and the movement of the body that are transmitted to the clothing through fine folding that transform into an unexpected event.

• 한국실내디자인학회논문집
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• 제22권3호
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• pp.127-134
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• 2013

Baroque is fundamentally in contrast with renaissance style classicism, which attempted to fix a world view itself as the value of perpetuity. Furthermore, it is interpreted as a topic of incompletion or transformation that is not defined or is not exemplary and which may be enjoyed by people in the classical life, which requires a microscopic concept in contrast with dualism, the central axis of western civilization, namely, rational lucidity. Also, such characteristics are estimated to serve as a lubricant in life while going beyond the formal aesthetic level of art even from a contemporary perspective, and to play a productive role and to have potential. Consequently, this paper assumed that the concepts expressed by the 20th century US contemporary architect Richard Meier of a complex space, namely architectural formative vocabularies such as overlapping, interpenetration, collision, and collage style mixture created by a layered structure, in his architecture are in common with the double surface technique and juxtaposition of a flat structure of Baroque architecture. Then, the paper analyzed and considered the characteristics. The paper considered the following two issues: Such Baroque style formal principle is reinterpreted against a backdrop in which his architectural flow based on the domino theory of Le Corbusier became established as his own unique architectural feature, and it may be proposed as one big flow that enables us to seek again modernistic architecture that attempts to make an architectural space absolute as an atypical formal contour.

• Journal of Communications and Networks
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• 제7권3호
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• pp.307-312
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• 2005

In this work, we study the performance of a serial concatenated scheme comprising a convolutional code (CC) and an orthogonal space-time block code (STBC) separated by an inter-leaver. Specifically, we derive performance bounds for this concatenated scheme, clearly quantify the impact of using a CC in conjunction with a STBC, and compare that to using a STBC code only. Furthermore, we examine the impact of performing antenna selection at the receiver on the diversity order and coding gain of the system. In performing antenna selection, we adopt a selection criterion that is based on maximizing the instantaneous signal-to­noise ratio (SNR) at the receiver. That is, we select a subset of the available receive antennas that maximizes the received SNR. Two channel models are considered in this study: Fast fading and quasi-static fading. For both cases, our analyses show that substantial coding gains can be achieved, which is confirmed through Monte-Carlo simulations. We demonstrate that the spatial diversity is maintained for all cases, whereas the coding gain deteriorates by no more than $10\;log_{10}$ (M / L) dB, all relative to the full complexity multiple-input multiple-output (MIMO) system.

• 천문학회보
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• 제42권2호
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• pp.62.1-62.1
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• 2017

In space weather forecast, it is important to determine three-dimensional properties of CMEs. Using 29 limb CMEs, we examine which cone type is close to a CME three-dimensional structure. We find that most CMEs have near full ice-cream cone structure which is a symmetrical circular cone combined with a hemisphere. We develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model). In addition, we derive CME mean density (${\bar{\rho}_{CME}}={\frac{M_{total}}{V_{cone}}}$) based on the full ice-cream cone structure. For several limb events, we determine CME mass by applying the Solarsoft procedure (e.g., cme_mass.pro) to SOHO/LASCO C3 images. CME volumes are estimated from the full ice-cream cone structure. For the first time, we derive average CME densities as a function of CME height for several CMEs, which are well fitted to power-law functions. We will compare densities (front and average) of geoeffective CMEs and their corresponding ICME ones.

• 한국통신학회논문지
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• 제31권8C호
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• pp.771-776
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• 2006

공간-시간 트렐리스 부호에서 기존에 제안된 ML(maximum likelihood) 복호법과 PRC(principal ratio combianing) 복호법을 아우르는 준최적 복호법인 GPRC(generalized PRC) 기법을 제안한다. GPRC는 수신안테나들을 K개의 그룹으로 나누어 각 그룹에 PRC 기법을 적용하는 것이다. GPRC에서는 수신안테나 그룹핑 방법이 여러 가지이므로 K가 정해졌을 때 최적의 그룹핑 규칙을 제안한다. 이때 최종 성능 차이를 간단하게 예측할 수 있는 성능지표(PI, performance index)를 이용할 수 있다. 특히 수신안테나 간 상관(correlation)이 있을 때 무선 채널 계수를 구하고, 성능 지표를 평가한다. 마지막으로 컴퓨터 시뮬레이션으로 이론적 성능을 검증한다.

• 한국항공우주학회지
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• 제39권8호
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• pp.719-724
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• 2011

비공기압 타이어(Non-Pneumatic tire)는 공기압 타이어와는 다르게 스포크(Spoke)로 공기압의 역할을 담당하는 새로운 타이어이다. 이 타이어는 공기압 타이어의 펑크에 대한 위험과 공기압 유지가 필요 없는 장접을 가졌으며, 공기가 존재하지 않는 우주에서도 사용이 가능하다. 본 연구에서는 음의 각으로 이뤄진 허니컴 구조의 비공기압 타이어를 수직 하중에 따른 접지압을 구하여, 이를 공기압 타이어와 비교하였다.