• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.12-17
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• 2000

In this paper, the frequency characteristics of flat fluorescent lamp(FFL) using ultraviolet generated from gas discharge are studied. The lamp is a simple structure with insulator layer, phosphor layer, and gas gap(1.1mm). The firing voltage and uniform voltage was decreased with increasing the frequency. It was considered that this tendency was resulted from the space charge effect due to Xe and Ar positive ions trapped in gas gap. Luminance in FFL using Xe as discharge gas was shown 2700 cd/$m^2$ in operation (700 Vrms, 80 kHz). Hence, the maximum luminous efficiency was 5 lm/W.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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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.

• The Journal of Sustainable Design and Educational Environment Research
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• v.13 no.1
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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.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.8
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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.

• Korean Institute of Interior Design Journal
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• v.22 no.3
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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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• v.7 no.3
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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.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8C
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• pp.771-776
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• 2006

We present a suboptimum decoding method for space-time trellis codes, which include maximum $likelihood(ML)^{[1]}$ and principal ratio $combining(PRC)^{[2]}$, over quasi-static flat fading channels. In the proposed scheme, the receive antennas are divided into K groups and the PRC is applied to each group, showing a flexible performances between ML and PRC. When K is determined, we also propose the optimum grouping rules and performance index(PI), which simply anticipate the relative performances. Moreover the performances are also evaluated when receive antennas are correlated. Finally, Computer simulations corroborate those theoretical results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.719-724
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• 2011

A Non_Pneumatic tire (NPT) has spoke to replace air of the pneumatic tires. A NPT appears to have advantages over the conventional pneumatic tire in terms of flat proof and maintenance free. And a NPT can also be used in the space environment since it uses no air for inflation. In this study, the static contact pressure of NPTs with auxetic honeycomb spokes is investigated as a function of vertical loading and is compared with that of a pneumatic tire. The finite element based numerical simulation of the local stress of an airless tire is carried out with ABAQUS for varying vertical force and honeycomb spokes geometries.