• 한국정보처리학회논문지
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• 제7권4호
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• pp.1033-1043
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• 2000

최근 NoD(News-on-Demand)에 대한 사용자의 요구가 증가함에 따라, 이러한 요구를 충족시키기 위한 많은 연구가 진행중에 있다. 그러니 뉴스 비디오 데디터는 짧은 생명주기, 앵커를 중시미으로 한 주기적 변화로인해 기존의 비디오 저장방식을 그대로 용하기가 어렵다. 이릉 위해, 본 논문에서는 NoD서비스용 멀티미디어 데이터의 효율적인 저장 및 검색을 위한 하부저장 관리자를 설계 및 구현하다. 하부 저장 관리자는 멀티미디어 객체 지체의 비디오 스트림 데이터와 색인 정보를 효율적으로 저장하고 관리하며, 텍스트 기반 검색을 위해 역화일 기법과 고차훤 특징 벡터의 색인을 위해 X-트리 구조를 제공한다. 아울러 하부 저장 관리자는 계층적인 뉴스 비디오 객체로부터 추출된 부가적인 정보들은 효율적으로 저장할 수 있는 저장 API(Application Program Interpace)와 커서를 통한 사용자의 편리한 검색을 지원하는 검색API를 제공한다. 마지막으로 하부 저장 관리자는 SHORE(Scalable Heterogeneous Object REpository) 저장 시스템을 이용하여 UNLX 운영체제 하엣 표준 C++언어를 사용하여 구현하였다. 구현하였다.

• 한국지능시스템학회논문지
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• 제21권4호
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• pp.499-505
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• 2011

본 논문은 파라미터 투영 기법이 필요없는 비선형 계통에 대한 적응 퍼지 슬라이딩 모드 제어를 제안한다. 제어기의 구조를 약간 수정하여 추정된 입력 이득항이 영으로 되지 않도록 보장하고 온라인 동작중의 어떤 순간이라고 추정된 입력 이득항이 영이 되더라도 구현에 문제를 야기하지 않는다. 입력 이득 함수의 하한 추정치만이 필요한것을 제외하면 제안한 제어 기법은 바운딩 파라미터에 대한 정확한 값이 사전에 필요하지 않다. 리아프노프 합성기법을 기초로 전체 제어 시스템이 추종오차가 점근적으로 안정하고 제어기 내의 모든 신호가 유계임을 보장한다. 역진자 시스템의 적용하여 제안한 제어기의 유용성을 입증한다.

• 한국측량학회지
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• 제32권3호
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• pp.245-251
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• 2014

As delineating market areas of retail businesses has become an interesting topic in marketing field, Lee and Lee recently suggested a noteworthy method, which applied the hydrological analysis of geographical information system (GIS), based on Christaller's central place theory. They used a digital elevation model (DEM) which inverted the kernel density of retail businesses, which was measured by using bandwidths of pre-determined 500, 1000 and 5000 m, respectively. In fact, their method is not a fully data-based approach in that they used pre-determined kernel bandwidths, however, this paper has been planned to improve Lee and Lee's method by using a kind of data-based approach of the L-index that describes clustering level of point feature distribution. The case study is implemented to automobile-related retail businesses in Seoul, Korea with selected Kernel bandwidths, 1211.5, 2120.2 and 7067.2 m from L-index analysis. Subsequently, the kernel density is measured, the density DEM is created by inverting it, and boundaries of market areas are extracted. Following the study, analysis results are summarized as follows. Firstly, the L-index can be a useful tool to complement the Lee and Lee's market area analysis method. At next, the kernel bandwidths, pre-determined by Lee and Lee, cannot be uniformly applied to all kinds of retail businesses. Lastly, the L-index method can be useful for analyzing the space structure of market areas of retail businesses, based on Christaller's central place theory.

• 대기
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• 제26권2호
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• pp.301-319
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• 2016

The evolutionary process of the polar low, which caused the heavy snowfall in the East Coast area on 11~12 February 2011, was investigated to describe in detail using synoptic weather charts, satellite imageries, and ERA (European Centre for Medium-Range Weather Forecasts Re-Analysis) -Interim reanalysis data. It was revealed that 1) the polar low was generated over the sea near Busan where a large cyclonic shear in the inverted trough branched from the parent low existed, 2) during the developing and mature stages, there was a convectively unstable region in the lower layer around the polar low and its south side, 3) the polar low was developed in the region where the static stability in the 500~850 hPa layer was the lowest, 4) the result from the budget analysis of the vorticity equation indicated that the increase in the vorticity at the lower atmosphere, where the polar low was located, was dominated mainly by the stretching term, 5) the warm core structure of the polar low was identified in the surface-700 hPa layer during the mature stage, 6) there was a close inverse relationship between a development of the polar low and the height of the dynamic tropopause over the polar low, and 7) for generation and development of the polar low, large-scale circulation systems, such as upper cold low and its combined short wave trough, major low (parent low), and polar air outbreak, should be presented, indicating that the polar low has the nature of the baroclinic disturbance.

• 천문학회보
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• 제36권2호
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• pp.61.1-61.1
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• 2011

We have performed simultaneous observations at 22GHz and 43GHz on AGNs hosted by elliptical galaxies using KVN radio telescope. We have constructed the sample, based on two major surveys in radio and optical band, i.e. Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) and Sloan Digital Sky Survey (SDSS) DR7, respectively. We restricted the redshift range 0.01 < z < 0.06 and the absolute magnitude Mr < -19.4 in order to satisfy volume limited sample. We also checked clear detection of four distinctive emission lines ([NII], [OIII], $H{\alpha}$, $H{\beta}$) so as to utilize on BPT diagram, distinguishing AGNs from star-forming galaxies. Elliptical galaxies have been selected by visual inspection making use of SDSS optical images. Then, we cross-matched the elliptical galaxies with FIRST detections. About 35% of the galaxies have been detected throughout KVN observations. We derive spectral index, applying the flux of different radio frequencies from FIRST (1.4GHz) and KVN (22GHz) and classify into steep, flat or inverted spectrum. We have found that most of the detected galaxies have flat spectrum while the rest of them have steep spectrum. This implies that a number of detected galaxies might have compact structure associated with the central region of the galaxies. The relation between black hole mass and radio luminosity has shown relatively tighter correlation in high frequency than in low frequency, which confirms that high frequency in radio band is appropriate to study the center of the galaxies.

• 한국전자파학회논문지
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• 제18권2호
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• pp.136-142
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• 2007

휴대폰 몸체 전류 변화를 이용하여 PIFA의 방사 패턴을 변화시키고, 휴대폰용 모노폴 안테나의 대역폭을 증가시키는 방법을 소개한다. 방사 패턴 변화를 위하여 후엽을 억제하는 변형된 접지면 구조를 제안하였으며, 그 결과 변형하기 전보다 0.5 dB의 이득 향상을 가져왔다. 대역폭 증가를 위하여 모노폴 안테나에 두 개의 공진 주파수를 형성시키도록 평행한 두 개의 기생 도체선을 추가하는 방법을 제안하였다. 대역폭은 341 MHz로 기존의 모노폴 안테나 구조보다 2배 이상 향상되었다.

• Wind and Structures
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• 제15권4호
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• pp.331-343
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• 2012

Thunderstorm downbursts are responsible for numerous structural failures around the world. The wind characteristics in thunderstorm downbursts containing vortex rings differ with those in 'traditional' boundary layer winds (BLW). This paper initially performs an unsteady-state simulation of the flow structure in a downburst (modelled as a impinging jet with its diameter being $D_{jet}$) using a computational fluid dynamics (CFD) method, and then analyses the pressure distribution on a solar updraft tower (SUT) in the downburst. The pressure field shows agreement with other previous studies. An additional pair of low-pressure region and high-pressure region is observed due to a second vortex ring, besides a foregoing pair caused by a primary vortex ring. The evolutions of pressure coefficients at five orientations of two representative heights of the SUT in the downburst with time are investigated. Results show that pressure distribution changes over a wide range when the vortices are close to the SUT. Furthermore, the fluctuations of external static pressure distribution for the SUT case 1 (i.e., radial distance from a location to jet center x=$D_{jet}$) with height are more intense due to the down striking of the vortex flow compared to those for the SUT case 2 (x=$2D_{jet}$). The static wind loads at heights z/H higher than 0.3 will be negligible when the vortex ring is far away from the SUT. The inverted wind load cases will occur when vortex is passing through the SUT except on the side faces. This can induce complex dynamic response of the SUT.

• Macromolecular Research
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• 제13권4호
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• pp.285-292
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• 2005

We developed alginate beads loaded with transforming growth $factor-{\beta}_{1}(TGF-{\beta}_{1})$ to examine the possible application of the scaffold and cytokine carrier in tissue engineering. In this study, bone marrow stromal cells (BMSCs) and $TGF{\beta}_{1}$ were uniformly encapsulated in the alginate beads and then cultured in vitro. The cell morphology and shape of the alginate beads were observed using inverted microscope, scanning electron microscope (SEM), histological staining and RT-PCR to confirm chondrogenic differentiation. The amount of the $TGF{\beta}_{1}$ released from the $TGF-{\beta}_{1}$ loaded alginate beads was analyzed for 28 days in vitro in a phosphate buffered saline (pH 7.4) at $37^{\circ}C$. We observed the release profile of $TGF-{\beta}_{1}$ from $TGF-{\beta}_{1}$ loaded alginate beads with a sustained release pattern for 35 days. Microscopic observation showed the open cell pore structure and abundant cells with a round morphology in the alginate beads. In addition, histology and RT-PCR results revealed the evidence of chondrogenic differentiation in the beads. In conclusion, these results confirmed that $TGF-{\beta}_{1}$ loaded alginate beads provide excellent conditions for chondrogenic differentiation.

• 한국광학회지
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• 제17권2호
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• pp.181-185
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• 2006

리튬나이오베이트 기판의 분극 반전 기술을 이용하여 300Hz 대역 광변조기를 제작하였고 60 GHz 광캐리어 발생기로 응용하였다. 주기적인 분극반전은 도파광과 RF사이의 QVM(Quasi-Velocity-Matching)을 유발하여 대역변조를 가능하게 하였다. 제작된 광변조기는 30.3 GHz에서 최대 변조효율을 보였으며, 3 dB 변조 대역폭은 약 5.1 GHz로 측정되었다. DSB-SC(Double Sideband Suppressed Carrier) 측정 실험을 통해 입사된 광 주파수로부터 30 GHz 간격으로 USB(Upper Sideband)와 LSB(Lower Sideband)를 발생시켰으며 입사광의 스펙트럼은 발생된 USB 혹은 LSB에 비해 28 dB정도 억제됨으로써, 30GHz 대역 광변조기가 60 GHz 광캐리어 발생기로 응용될 수 있음을 보였다.

• 한국동물학회지
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• 제39권2호
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• pp.164-172
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• 1996

KP elements derived from Korean populations (Seoul, Cheonan and Taegu) of Drosophila melunoguster were examined for their molecular structure. The entire 1.15 kb sequence of the three KP elements KC-137 (Cheonan), KS-95 (Seoul) and KT-99 (Taegu) have been obtained by PCR amplification using inverted repeat primers and DNA sequencing. The 1.15 kb fragments of KP elements were cloned into pCRmll vector plasmids, and subsequently sequenced. The sequence of the three KP elements in these populations suggested that there might have been derived from the complete P element by a 1753 bp internal deletion between positions 808 and 2560. Therefore these KP elements were confirmed to be identical to that isolated from M'10 strains widely distributed in most Eurasian populations of D. melanoguster. Sequence comparison with the 2.9 kb complete P element in pn25.1 revealed that KC-137 has only shown to be two base substitutions of A to G and G to A at positions 62 and 242, respectively. The retained sequence of the two KP elements KS-95 and KT-99 shows complete homology to the P factor in pn25.1. Based on this result, the two base substitutions in KC-137 might be due to Taq DNA pollunerase errors. Finally, it is suggested that the high copy numbers of KP elements provieds an explanation for the suppression of P-mediated hybrid dvssenesis in Korean population of D. melunogoster.