• 융합신호처리학회논문지
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• 제11권2호
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• pp.104-111
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• 2010

본 논문은 DCT 압축 영역에서 공간 주파수 특성을 이용한 적응 영상향상 방법에 관한 것이다. 영상의 동적범위를 압축하기 위해 Retinex 이론을 이용하여 영상의 조명성분인 dc 계수들을 조절하였으며, 대비를 개선하기 위해 인간의 시각 체계와 계수들의 공간 주파수 특성을 이용하여 ac 계수들을 수정하였다. 세로 방향, 가로 방향, 그리고 혼합된 공간 주파수 성분으로 분류된 ac계수들은 영상향상에 발생하는 블록화 현상을 최소화하기 위하여 적응적으로 수정하였다. 제안된 방법은 영상의 동적 범위 압축과 적응적 대비 개선을 이용하여 기존 방법보다 블록화 현상이 없는 효과적인 영상 향상의 결과를 가져왔다.

• Advances in nano research
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• 제2권2호
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• pp.121-133
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• 2014

Polymer nanocomposites are advanced nanomaterials which exhibit dramatic improvements in various mechanical, thermal and barrier properties as compared with the neat polymer. Polystyrene/ alumina nanocomposites were prepared by an ultrasound-assisted solution casting method at filler loadings ranging from 0.2 to 2% and also at different ultrasonic frequencies, viz. 58 kHz, 192/58 kHz, 430 kHz, 470 kHz and 1 MHz. The composites were subjected to mechanical property tests (tensile and impact tests) and cavitation erosion tests to study the enhancement in functional properties. Filler dispersion in the polymer matrix was observed by SEM analysis. The effect of frequency on filler dispersion in the matrix was studied by SEM analysis and functional property enhancement of the composite material. The composites prepared at dual (high/ low) frequency (192/58 kHz) were found to show better property enhancement at low filler loadings as compared with neat polymer and also with composites prepared without ultrasound, thus reinforcing the finding that ultrasound-assisted synthesis is a promising method for the synthesis of nanocomposites.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.657-658
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• 2010

• 대한산업공학회지
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• 제32권4호
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• pp.358-368
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• 2006

The significance of intellectual property in the knowledge-based society has been increasing and as a result, the patent customer's demand for a top quality patent administration service has increased as well. Therefore, Korean Intellectual Property Office(KIPO) adopted 6 sigma as a tool for KIPO's innovation to improve the quality of patent administration and enhance customer satisfaction. KIPO's steadfast promotion of 6 sigma resulted in many successful outcomes such as improvement of policy and service process from customer's point view, streamlining the administrative procedures, increased work efficiency, capability enhancement of core personnel, and so on. Since 6 sigma has proved itself to be equipped with features suitable for innovation in public sector, it can be used as an extensible innovation tool to meet the challenges in rapidly changing administration environment and to achieve a competitive edge.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.3-4
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• 2002

The stainless steel sheathed MgB$_2$ tapes with Cu addition were fabricated by PIT method without heat treatment. The $J_{c}$ value of 5,600 A/ $cm^{2}$and 16,000 A/$cm^{2}$ at 4.2 K and 5 T were obtained for the $MgB_{2}$ tape and 10 vol % of Cu added $MgB_{2}$ tape respectively. The $J_{c}$-B curve shows enhancement in J$_{c}$ under magnetic field, which suggests enhancement in flux pinning property with Cu addition.n.

• 전기학회논문지
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• 제59권6호
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• pp.1120-1125
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• 2010

In the speech system, for example hearing aid as well as speech communication, speech quality is degraded by environmental noise. In this study, to enhance the speech quality which is degraded by environmental speech, we proposed an algorithm to reduce the noise and reinforce the speech. The minima controlled recursive averaging (MCRA) algorithm is used to estimate the noise spectrum and spectral weighting factor is used to reduce the noise. And partial masking effect which is one of the human hearing properties is introduced to reinforce the speech. Then we compared the waveform, spectrogram, Perceptual Evaluation of Speech Quality (PESQ) and segmental Signal to Noise Ratio (segSNR) between original speech, noisy speech, noise reduced speech and enhanced speech by proposed method. As a result, enhanced speech by proposed method is reinforced in high frequency which is degraded by noise, and PESQ, segSNR is enhanced. It means that the speech quality is enhanced.

• Journal of Magnetics
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• 제14권3호
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• pp.104-107
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• 2009

The effects of the magnetic property variation on current-induced magnetization switching in magnetic tunnel junction with perpendicular magnetic anistoropy (PMA) and the soft magnetic polarization-enhancement layers (PELs) inserted between the layers with PMA and the MgO layer was studied. A micromatnetic model was used to estimate the switching time of the free layer by different applied current densities, with changing saturation magnetization ($M_s$) of the PELs, interlayer exchange coupling between PMA layers and PELs. The switching time could be significantly reduced at low current densities, by increasing $M_s$ of PELs and decreasing interlayer exchange coupling.

• Journal of electromagnetic engineering and science
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• 제5권2호
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• pp.49-60
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• 2005

In this paper, an efficient performance enhancement scheme for an adaptive antenna array under the flat and the frequency-selective Rayleigh fadings is proposed. The proposed signal enhancement scheme is the modified linear signal estimator which combines the rank N approximation by reducing noise eigenvalues(RANE) and Toeplitz matrix approximation(TMA) methods into the linear signal estimator. The proposed performance enhancement scheme is performed by not only reducing the noise component from the signal-plus-noise subspace using RANE but also having the theoretical property of noise-free signal using TMA. Consequently, the key idea of the proposed performance enhancement scheme is to greatly enhance the performance of an adaptive antenna array by removing all undesired noise effects from the post-correlation received signal. The proposed performance enhancement scheme applies at the Wiener maximal ratio combining(MRC) method which has been widely used as the conventional adaptive antenna array. It is shown through several simulation results that the performance of an adaptive antenna array using the proposed signal enhancement scheme is much superior to that of a system using the conventional method under several environments, i.e., a flat Rayleigh fading, a fast frequency-selective Rayleigh fading, a perfect/imperfect power control, a single cell, and a multicell.

• 전기전자학회논문지
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• 제21권3호
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• pp.288-296
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• 2017

The enhancement of photoluminescence of Au-$TiO_2$ nanoparticles by surface plasmon resonance has been studied extensively by experiment in recent years. For the purpose of optimizing the photoluminescence property of Au-$TiO_2$ nanoparticles, the manufacturing parameters related to the Au nanoparticles and $TiO_2$ nanoparticles need to be considered. In this paper, Drude model and Maier's effective volume method are used to analyze the variation of the metal nanoparticle radius, separation between metal nanoparticle and dielectric molecule, and total absorption cross-section with original radiative efficiency on the photoluminescence property of Au-$TiO_2$ nanoparticles. The results show that to obtain the optimized enhancement factor for photoluminescence process, the size of Au nanoparticle is about 13 - 20 nm, the separation between Au nanoparticle and $TiO_2$ molecule is about 5 -15 nm, the total absorption cross-section of $TiO_2$ molecules is about $1-100nm^2$ and the original radiative efficiency of $TiO_2$ molecule is weak about 0.001- 0.1. With these fabrication parameters, the photoluminescence property of Au-$TiO_2$ nanoparticles can be enhanced several thousand times compared to traditional $TiO_2$ nanoparticles.

• 헤리티지:역사와 과학
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• 제36권
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• pp.39-67
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• 2003

In this paper we examine cultural properties of the North Korea from 'the law of the Democratic People's Republic of Korea on Protection of Cultural Property". This law was adopted the Resolution of the Standing Committee of the Supreme People's Assembly of DPR of Korea in 1994. For our study, some other laws or rules established after the end of Japanese colonial occupation (1910-1945) in North Korea were examined. The policy on protection and conservation of cultural property in North Korea seems to have taken place a relatively rapid. The purpose of this law is to carry out the policy with a view to contributing to establishment of strict system and order for protection and management of cultural property, to their preservation in original state, to their proper inheritance and development, and to enhancement of national pride and confidence among the people. This law consists of 6 chapters (52 articles): (1) Fundamentals of the law on protection of cultural property, (2) Archaeological excavation and collection of cultural relics, (3) Evaluation and registration of cultural property, (4) Preservation and management of cultural property, (5) Restoration of cultural property, and (6) Guidance and control of cultural property protection. Nevertheless, it is difficult to find the evidence of efforts to exploit the cultural properties from an academic point of view in North Korea since the late 1980s.