• Journal of KIISE:Software and Applications
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• v.33 no.1
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• pp.84-94
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• 2006

The color information in an image changes as the illuminant condition varies. The mechanism to find canonical color of an object by estimating illumination color in an image is generally referred as color constancy. In color constancy, computing robust and precise dichromatic line is most important to estimate illumination chromaticity. In this paper, a novel approach to estimate the color of a single illuminant for noisy and micro-textured images is introduced. An accurate dichromatic line is found by using Dichromatic Line Space (DLS), proposed in this paper. which has information about diffuse chromaticity and illumination chromaticity.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2966-2970
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• 2012

Fullerene/polystyrene ($C_{60}$/PS) nano particle was prepared by using emulsion polymerization. Styrene and fullerene were emulsified in aqueous media in the presence of poly(N-vinyl pyridine) as an emulsion stabilizer, and polymerization was initiated by water soluble radical initiator, potassium persulfate. The obtained nano particles have an average diameter in the range of 400-500 nm. The fullerene contents in the nano particle can be controlled up to 15 wt % by varying the feed ratio, which was confirmed by themogravimetric analysis (TGA) and elemental analysis (EA). The structure and morphologies of the $C_{60}$/PS nano particles were examined by various analytical techniques such as dynamic light scattering (DLS), scanning electron microscope (SEM), transmission electron microscope (TEM), electron diffraction (ED) pattern, X-ray powder diffraction (XRD), and UV spectroscopy. Unlike conventional $C_{60}$/PS particles initiated by organic free radical initiators, in which the fullerene is copolymerized forming a covalent bond with styrene monomer, the prepared $C_{60}$/PS nano particles contain pristine fullerene as secondary particles homogeneously distributed in the polystyrene matrix.

• Journal of the Korean Society for Library and Information Science
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• v.38 no.3
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• pp.119-139
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• 2004

This study intends to evaluate the quality of the Digital Library System DB and to suggest methods for its quality control. The evaluation criteria are hit rates, redundancy, completeness and accuracy. In spite of high hit rates excessive records representing one work resulted serious redundancy. The average completeness rate of records was $48.12\%$ due to low level of description. The Analysis of accuracy showed various errors in most of records corresponding to $92\%$. Emphasis on analysing the errors in detail detected the causing factors and suggested practical guidelines for school libraries' catalogers.

• KSTLE International Journal
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• v.6 no.1
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• pp.28-32
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• 2005

The electrorheoloRical (ER) fluids are composed of a colloidal dispersion of polarizable particles in insulating oil, and it's the rheological property changes by the applied electric field. These changed are reversible and occur fast within a fewmilliseconds. The ER properties of the ER fluid such as increment of viscosity and yield stress come from the particle chain structure induced by electric fleld. When formulating the ER fluid for a speciflc application, some requirement must besatisfled, which are high yield stress under electric field, rapid response, and dispersion stability. While this characteristic makes valuable ER fluids in valious industrial applications, their lung term and quiescent application has been limited because ofproblems with particle sedimentation. In an effort to overcome sedimentation problem of ER fluids, the anhydrous ER materials of monodispersed hollow polyaniline (PANI) and adipate derivative respectively with submicron-sized suspension providing wide operating temperature range and other advantage were synthesized in a four-step procedure. The ER fluidswere characterized by FT-lR, TGA, DLS, SEM, and TEM. Stability of the suspensions was examined by an UV spectroscopy.The rheological and electrical properties of the suspension were investigated Couette-type rheometer with a high voltagegenerator, current density, and conductivity. And the behavior of ER suspensions was observed by a video camera attached toan optical microscope under 3kV/mm. The suspensions showed good ER properties, durability, and particle dispersion.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.63-72
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• 1992

본 연구의 목적은 교환기 및 가입자 선로에 대한 투자계획의 수립 즉 적정수준의 공급주기와 공급량을 산정하는 방안을 모색해 보는 것이다. 이와 같은 연구를 수행하기 위하여 우선 한국통신의 공급계획수립업무에 대한 현황파악과 함께 한국통신의 공급계획수립에 적용할 수 있는 이론적 모형을 다각도로 검토해 보았다. 그 결과 재고모형이 가장 적합하다고 판단되어 재고모형의 여러 대안을 현행 공급계획수립방법과 비교하여 공급주기와 총비용을 비교분석하였다. 본 연구에서는 Economic Order Quantity(EOQ)모형, Dynamic Lot Size(DLS)모형, 그리고 Simulation이 분석의 도구로 사용되었으며, Simulation은 두가지 방법을 적용하였다. 첫번째 방법은 개별 전화국을 대상으로 simulation을 실시하여 최소의 비용을 보이는 공급주기를 각 전화국별로 산정하는 것이며, 두번째 방법은 모든 전화국에 동일한 공급주기를 적용하여 개별 전화국에서 발생하는 비용의 총합계가 최소화되는 공급주기를 산정하는 것이다. 각 대안별로 공급주기와 총비용을 산정해 본 결과 교환기의 경우는 총비용면에서 현행방법과 본 연구에서 제안한 대안들간에 커다란 차이는 없었으나, 모든 전화국에 동일한 공급주기를 일률적으로 적용시키는 것보다 각 전화국의 수요증가형태에 맞는 공급주기를 별도로 산정하여 적용시키는 것이 보다 경제적이었다. 한편, 가입자선로의 경우는 본 연구에서 제시한 대안들이 현행방법에 비해 연간 수백억원에 이르는 투자지출을 절감 할 수 있음을 보였다.

• Journal of Powder Materials
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• v.24 no.3
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• pp.216-222
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• 2017

Synthesized monocrystalline nanodiamond (nD) particles are heat-treated at various temperatures to produce highly structured diamond crystals. The heat-treated nDs show different weight loss ratios during thermogravimetric analysis. The crystallinities of the heat-treated nDs are analyzed using Raman spectroscopy. The average particle sizes of the heat-treated nDs are measured by a dynamic light scattering (DLS) system and direct imaging observation methods. Moreover, individual dispersion behaviors of the heat-treated nD particles are investigated based on ultrasonic dispersion methods. The average particle sizes of the dispersed nDs according to the two different measurement methods show very similar size distributions. Thus, it is possible to produce highly crystallized nD powder particles by a heat-treatment process, and the nD particles are relatively easy to disperse individually without any dispersant. The heat-treated nDs can lead to potential applications such as in nanocomposites, quantum dots, and biomedical materials.

• Journal of Korean Library and Information Science Society
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• v.40 no.1
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• pp.363-384
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• 2009

School library programs are a specific strategy connecting user to resources. Accordingly in order to strengthen school libraries, it is necessary for teacher librarians to develop partnerships that can form relationships between internal and external resources. As a result of analyses of partnerships appeared in current middle school library programs, its most programs are based on the internal reading events. In addition to, classroom teachers and external human resources rarely participate in the program. To improve these problems, it is essential to develop teacher librarians' leadership and collaborative networks fostering educational presence of school libraries in a learning community.

• Journal of Biomedical Engineering Research
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• v.39 no.3
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• pp.140-145
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• 2018

Cancer is a major burden of human disease worldwide. Current chemotherapy has severe side effects because the drugs affect whole body nonspecifically. In addition, the drugs to reach cancer cells are very limited. Over the last two decades, Drug Delivery System (DDS) using nanoparticles has suggested promising results to improve current limitations. In this study, we prepared PLGA nanoparticles with different charge properties and observed their stability and internalization effect to cancer cells. Results using Dynamic Light Scattering (DLS) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the size and chemical composition of the nanoparticles. The stability of the nanoparticles in pH buffers were variable depending on charge properties. The nanoparticles showed different cytotoxicity and internalization effects to MCF-7 human breast cancer cells. In conclusion, we demonstrated the importance of delicately engineered nanoparticles for better DDS in cancer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.497-507
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• 2014

This paper investigates the standard features of Carrier aggregation (CA), the related UE RF requirements in 3GPP release 12 and estimated CA evolution in future. The main CA feature of 3GPP release 12 in WG4 perspectives includes 2Uplink(UL) CA, 3Downlink(DL) CA and TDD-FDD CA. To support these features in UE, UE-to-UE coexistence problem and RF requirements generated by unwanted emissions such as inter-modulation and harmonics are analyzed. Also, future CA technology such as LTE in unlicensed bands is described.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.185-188
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• 2006

We studied on the reverse twist near the pixel edge depending on the rubbing direction for the fringe field switching (FFS) mode. Liquid crystal (LC) dynamic and the transmittance near the pixel edge, where the various field directions are generated, depend on the initial rubbing direction because the position of reverse twist is decided by the angle between the electric direction and the LC director at a bias voltage. For example, when the rubbing angle is $7^{\circ}$, the reverse twist appears on the bottom position of the right sharp comer of the pixel edge so that the reverse region exists far away from main active region. But, when the rubbing angle is $-7^{\circ}$, the reverse twist appears on the top position of the right sharp comer of the pixel edge, resulting that the region becomes more close to the main active area and the unstable disclination lines (DLs) easily intrude into the active region. Therefore, it is necessary to keep the reverse twist region far from the active region and it is possible by controlling the rubbing direction in the design of a pixel electrode.