• 대기
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• 제20권3호
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• pp.343-353
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• 2010

A regional wind network with complex surface conditions must be designed with sufficient space and time resolution to resolve the local circulations. In this study, the spatial variations of the wind field observed in the Seoul and Jeju regional networks were evaluated in terms of annual, seasons, and months to assess the spatial homogeneity of wind fields within the regional networks. The coherency of the wind field as a function of separation distance between stations indicated that significant coherency was sometimes not captured by the network, as inferred by low correlations between adjacent stations. A meso-velocity scale was defined in terms of the spatial variability of the wind within the network. This problem is predictably most significant with weak winds, dull prevailing wind, clear skies and significant topography. The relatively small correlations between stations imply that the wind at a given point cannot be estimated by interpolating winds from the nearest stations. For the Seoul and Jeju regional network, the meso-velocity scale has typically a same order of magnitude as the speed of the network averaged wind, revealing the large spatial variability of the Jeju network station imply topography and weather. Significant scatter in the relationship between spatial variability of the wind field and the wind speed is thought to be related to thermally-generated flows. The magnitude of the mesovelocity scale was significantly different along separation distance between stations, wind speed, intensity of prevailing wind, clear and cloudy conditions, topography. Resultant wind vectors indicate much different flow patterns along condition of contributing factors. As a result, the careful considerations on contributing factors such as prevailing wind in season, weather, and complex surface conditions with topography and land/sea contrast are required to assess the spatial variations of wind field on a regional network. The results in the spatial variation from the mesovelocity scale are useful to represent the characteristics of regional wind speed including lower surface conditions over the grid scale of large scale atmospheric model.

• ETRI Journal
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• 제27권3호
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• pp.294-303
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• 2005

In this paper, a supervised algorithm for the evaluation of geophysical sites using a multi-level cellular neural network (ML-CNN) is introduced, developed, and applied to real data. ML-CNN is a stochastic image processing technique based on template optimization using neighborhood relationships of the pixels. The separation/enhancement and border detection performance of the proposed method is evaluated by various interesting real applications. A genetic algorithm is used in the optimization of CNN templates. The first application is concerned with the separation of potential field data of the Dumluca chromite region, which is one of the rich reserves of Turkey; in this context, the classical approach to the gravity anomaly separation method is one of the main problems in geophysics. The other application is the border detection of archeological ruins of the Hittite Empire in Turkey. The Hittite civilization sites located at the Sivas-Altinyayla region of Turkey are among the most important archeological sites in history, one reason among others being that written documentation was first produced by this civilization.

• 한국정보처리학회논문지
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• 제6권2호
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• pp.543-551
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• 1999

본 논문의 목적은 필기 숫자 인식에서 특징의 부류 분별력을 분석하고, 이를 특징 선택에 활용하는 것이다. 부류 분별력을 측정하기 위하여 Parzen 윈도우를 이용하여 부류 분포를 추정하였고, 서로 다른 부류의 부류 분포간의 거리를 부류 분별로 정의하였다. 이렇게 계산된 부류 분별을 이용하여, 특징 벡터에서 쓸모 없거나 중복성을 갖는 특징을 제거하여 특징 벡터의 차원을 줄인다. 실험은 CENPARMI 필기 숫자에 대해 수행하였으며 10개 부류 전체 뿐 아니라 2개 부류에 대해서도 수행하였다. 실험 결과 10-부류 필기 숫자 인식에서 256-차원 원래 특징 벡터를 인식률 손실 없이 22% 줄일 수 있어, 부류 분별이 특징 선택을 위한 유용한 도구임을 보였다.

• 멤브레인
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• 제2권1호
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• pp.36-36
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• 1992

This paper deals with the separation of MTBE-methanol mixtures using crosslinked Poly(vinyl alcohol)(PVA) membranes with sulfur-succinic acid(SSA) as a crosslinking agent by pervaporation and vapor permeation technique. The operating temperatures, methanol concentration in feed mixtures, and SSA concentrations in PVA membranes were varied to investigate the separation performance of PVA/SSA membranes and the optimum separation characteristics by pervaporation and vapor permeation. And also, for PVA/SSA membranes, the swelling measurements were carried out to study the transport phenomena. The swelling measurements were carried out for pure MTBE and methanol, and MTBE/methanol=90/10, 80/20 mixtures using PVA/SSA membranes with varying SSA compositions. There are two factors of the membrane network and the hydrogen bonding. In pervaporation separation was also carried out for MTBE/methanol=90/10, 80/20 mixtures at various temperatures. The sulfuric acid group in SSA took an important role in the membrane performance. The crosslinking effect might be over the hydrogen bonding effect due to the sulfuric acid group at 3 and 5% SSA membranes, and this two factors act vice versa on 7% SSA membrane. In this case, the 5% SSA membrane shows the highest separation factor of 2,095 with the flux of 12.79g/㎡·hr for MTBE/methanol=80/20 mixtures at 30℃ which this mixtures show near the azeotopic composition. Compared to pervaporation, vapor permeation showed less flux and similar separation factor. In this case, the flux decreased significantly because of compact structure and the effect of hydrogen bonding. In vapor permeation, density or concentration of methanol in vaporous feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membranes shows the highest separation factor of 2,187 with the flux of 4.84g/㎡·hr for MTBE/methanol=80/20 mixtures at 30℃.

• Korean Membrane Journal
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• 제2권1호
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• pp.36-47
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• 2000

This paper deals with the separation of MTBE-methanol mixtures using crosslinked Poly(vinyl alcohol)(PVA) membranes with sulfur-succinic acid(SSA) as a crosslinking agent by pervaporation and vapor permeation technique. The operating temperatures, methanol concentration in feed mixtures, and SSA concentrations in PVA membranes were varied to investigate the separation performance of PVA/SSA membranes and the optimum separation characteristics by pervaporation and vapor permeation. And also, for PVA/SSA membranes, the swelling measurements were carried out to study the transport phenomena. The swelling measurements were carried out for pure MTBE and methanol, and MTBE/methanol=90/10, 80/20 mixtures using PVA/SSA membranes with varying SSA compositions. There are two factors of the membrane network and the hydrogen bonding. In pervaporation separation was also carried out for MTBE/methanol=90/10, 80/20 mixtures at various temperatures. The sulfuric acid group in SSA took an important role in the membrane performance. The crosslinking effect might be over the hydrogen bonding effect due to the sulfuric acid group at 3 and 5% SSA membranes, and this two factors act vice versa on 7% SSA membrane. In this case, the 5% SSA membrane shows the highest separation factor of 2,095 with the flux of 12.79g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$ which this mixtures show near the azeotopic composition. Compared to pervaporation, vapor permeation showed less flux and similar separation factor. In this case, the flux decreased significantly because of compact structure and the effect of hydrogen bonding. In vapor permeation, density or concentration of methanol in vaporous feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membranes shows the highest separation factor of 2,187 with the flux of 4.84g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 동계학술대회 논문집
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• pp.59-59
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• 2004

• 에너지공학
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• 제4권1호
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• pp.13-22
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• 1995

공정산업에서 열교환망의 최적화를 통한 에너지 회수 및 절감 기술의 개발을 목적으로, 여러 개의 핀치를 갖거나 또는 안전 및 배열 등과 같은 제약조건들이 주어진 계를 대상으로, 계의 분리법(system separation method)을 적용하여 신뢰도가 높은 목표값(target)을 설정하는 연구의 일환이다. 본 연구에서는 그 목표값의 10% 이내에 도달할 수 있도록 실제적인 열교환망 합성을 수행하는 프로그램 개발에 중점을 두었으며, 조업 중인 기존 공정에 적용해 본 결과, 연간 총비용의 15% 정도를 절감할 수 있는 결과를 얻을 수가 있었다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 가을 학술발표논문집 Vol.27 No.2 (3)
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• pp.393-395
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• 2000

현재 인터넷이 직면하고 있는 IP 주소 부족문제 해결을 위한 새로운 방안으로서 데이터 플로우 구별에 의한 네트워크 주소 변환(NAT-FS : NAT by Flow Separation) 기법을 제안하고 기술한다. 이 방식은 기존의 NAPT와 같이 단 하나의 글로벌 IP 주소에 모든 로컬 호스트가 할당되면서도 Basic NAT 방식처럼 DNA와 연동하여 Full Access 기능도 지원할 수 있다.

• 융합보안논문지
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• 제23권1호
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• pp.125-137
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• 2023

공공기관을 필두로 민감정보를 취급하는 기업들은 사이버 공격 예방을 위하여 업무망과 인터넷망을 분리 구축하고, 강한 접근통제를 바탕으로 중요 데이터를 보호하고 있다. 그렇기에 업무망과 인터넷망이 연결되는 접점을 수반하는 시스템은 관리적, 기술적으로 안전한 보안환경 구축이 필수적으로 요구되고 있다. 기관에서 사용하고자 하는 모바일 장치의 경우 기기를 통제하기 위한 MDM(Mobile Device Management) 솔루션이 그 예라 할 수 있다. 이 시스템은 모바일 장치 정보, 사용자 정보 등의 민감정보를 인터넷망에서 취급하여 동작하므로 운영 시 각별한 보안대책이 요구된다. 본 연구에서 인터넷망에서 반드시 운영되어야 하는 시스템에서의 민감정보 데이터 처리를 내부망에서 관리할 수 있도록 모델을 제시하였으며, 이를 망연동 솔루션을 기반으로 한 MDM 솔루션을 중심으로 기능 설계 및 구축하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.943-945
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• 2013

슈반세포의 수초화에 대한 연구는 일차 슈반세포의 분리와 배양의 성공에 의해 가능해지고 있다. 본 연구에서는 슈반세포의 근원으로서 마우스 배아의 척수신경절이 사용되었다. 이 방법에는 세 가지 단계가 있다. 첫 단계는 배아의 척수신경절의 파쇄이고 두 번째 단계는 섬유아세포로부터 슈반세포-뉴런 연합체의 기계적인 분리에 의한 슈반세포의 전구세포의 확장이며 세 번째 단계는 뉴런으로 부터 슈반세포의 분리와 분리된 슈반세포의 확장이다. 우리는 본 과정을 통해 짧은 시간이내에 슈반세포-뉴런 연합체와 슈반세포를 고순도로 분리하였다.