금속선 광 도파로를 이용한 장거리 표면-플라즈몬 파장가변 필터

김기철,송석호,원형식,이관수,Kim, Ki-Cheol,Song, Seok-Ho,Won, Hyong-Sik,Lee, Gwan-Su 한국광학회 2006 한국광학회지 Vol.17 No.4

금으로 된 금속선 광 도파로를 따라 속박되는 장거리 표면 플라즈몬을 이용하여 파장 가변 필터를 설계하고 제작하였다. 실리콘 기판 위에 제작된 금속선 도파로는 두 층의 열광학 폴리머 사이에 샌드위치 구조로 끼어 있도록 설계되었다. 도파로의 바로 윗면에는 유전체로 된 Bragg 회절격자가 적합한 주기로 제작되어, 중심 파장이 광통신 파장대 (1520$\sim$1570 nm)에 있으면서 높은 소광률($\sim$25 dB)을 갖는 파의 반사가 가능했고, 전체손실은 25 dB/cm 이하로 나타났다. 또한, 제작된 파장 가변 필터가 폴리머의 열-광학적 특성에 의해 파장가변 필터 소자로서의 응용이 가능함을 확인했으며, 금속선 광 도파로에 직접 연결된 전극 구조에 동시에 가해준 전류에 의해 파장이 가변 될 수 있음을 실험적으로 확인하였다. We design and fabricate a novel tunable wavelength filter, which utilizes long-range surface plasmon-polaritons excited along nm-thick-metal strips. A gold metal strip, with $\sim$ cm length, 20 nm thickness, and $\sim$ 5$\mu$m width, is embedded in thick thermo-optic Polymer films supported by a silicon wafer. A dielectric Bragg grating structure is Placed on the metal strip, so that transmission signals at telecom wavelength are selected by thermal effect of the thermo-optic polymer. High extinction ratio of 25 dB and total insertion loss of $\sim$25 dB/cm can be measured by single-mode coupling of optical fibers. We also verify that wavelength tuning of the long-range surface plasmon-polariton filters can be achieved by electric current directly applied to the metal-strip waveguides.

건물의 냉방을 위한 해수열 취득에 관한 실험적 연구

김기철,이성,Kim Ki-Cheol,Lee Seong 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.8

The industrial growth and the raised living quality have led to the massive energy consumption. As a result. the polluted environment and the limited amount of energy resources emerged as serious problems to be resolved in 21st century. Especially, in the case of Korea whose imported energy dependency rate is 98.2$\%$ in 2003 and constantly increasing every rear. more than 24$\%$ of overall energy consumption is for housing and commercial use. In order to cope with the shortage of natural energy resources, it is inevitable to develop alternative sustainable energy resources including seawater heat. so that they can replace existing resources. The heat transfer air velocity 3.5 m/s is proper to consideration with the body the pipe size 200A is more suitable than look due to the air velocity quantify and the ratio of pipe surface area. And the error between experimental data with simulation is below 5.34$\%$ so the suggested equation for calculating heat transfer capacity can be used. Therefore out of many methods utilizing seawater heat. this work Presents the efficiency of using sea water heat as a resource for air-conditioners which can be converted from the outside air through the air-to-heat conversion tube . Consequently. this method provides pretty reasonable energy efficiency.

하구둑 방류와 환경적 인자에 따른 낙동강 하구 지역 해저 지형변화 연구

김기철,김성보,Kim, Ki-cheol,Kim, Sung-Bo 한국환경과학회 2021 한국환경과학회지 Vol.30 No.7

In this study, the bathymetric data acquired from 2018 to 2020 and the precipitation and suspended sediment data were analyzed for changes in bathymetry owing to the discharge from the Nakdong River barrier and environmental factors, especially the torrential rain in 2020. Sediment erosion and deposition processes are repeated because of complex environmental factors such as discharge from the Nakdong River barrier and the influence of waves generated from the external sea. In the first half of the year after the dry season, bathymetric data showed relative erosion trends, whereas in the second half after the flood season, deposition trends were identified owing to the increase in sediment transport. However, the data from the second half of 2020 showed a large amount of erosion, resulting in tendencies different to those of erosion in the first half and deposition in the second half of the year. This result is judged to be influenced by the weather in the summer of 2020. The torrential rain in the summer of 2020 resulted in a higher force of erosion than that of deposition. In summary, the tendency for erosion is more significant than that of sedimentation, especially in the main channel area of the Nakdong River.

방향분포를 이용한 지문인식

김기철,최승문,이정문,Kim Ki-Cheol,Choi Seung-Moon,Lee Jung-Moon 한국디지털콘텐츠학회 2001 한국디지털콘텐츠학회논문지 Vol.2 No.2

본 논문에서는 지문의 방향분포를 기반으로 하여 전처리과정을 최소화하고 특징벡터의 크기를 축소하여 개인의 인증 및 인식 시스템에서의 시스템 처리속도와 검색속도 향상을 주된 연구목적으로 하였다. 지문의 방향분포는 지문의 융선과 골이 이루는 부분적인 방향성분의 집합으로서 가버필터 뱅크를 통해 8-방향 성분들로 추출된다. 이렇게 생성된 방향분포는 불연속적인 특성을 갖게 되는데 이를 연속적인 방향성분으로 근사화하여 방향영상으로 시각화한다. 이 후 지문의 중심 이 되는 기준점을 설정하고 기준점으로부터 32-방향, 6-단계 거리에 미리 정해진 192개 지점에서의 방향성분값들을 추출하여 특징벡터를 생성한다. 그 결과 기존의 다른 알고리즘보다 작은 크기의 특징벡터를 사용함으로써 전체 처리속도는 훨씬 증가하면서도 같은 수준의 인식률을 얻을 수 있었다.

반도체 클린룸용 증기가습 및 수분무가습 외기공조시스템의 에너지소비량 평가

김기철(Ki-Cheol Kim),송근수(Gen-Soo Song),김형태(Hyung-Tae Kim),유경훈(Kyung-Hoon Yoo),신대건(Dae-Kun Shin),박덕준(Dug-Jun Park) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.2

For a large-scale semiconductor manufacturing clean room, the energy consumed in an outdoor air conditioning system to heat, humidify, cool and dehumidify incoming outdoor air is very large. In particular, the energy requirement to humidify outdoor air in the winter season is generally known to be high. Recently, in order to overcome the high energy consumption nature of a steam generator in a conventional steam humidification type outdoor air conditioning system, an air washer is often introduced instead of the steam generator in the outdoor air conditioning system, which can be called a water spray humidification type outdoor air conditioning system. Therefore, the assessment and comparison of the annual energy consumed in the steam humidification type and the water spray humidification type outdoor air conditioning systems deserves to be examined in order to reduce the outdoor air conditioning load of a clean room. In the present study, a numerical analysis was conducted to obtain the annual electric power consumption of the two outdoor air conditioning systems. It was shown from the comparison of the numerical results that the water spray humidification type outdoor air conditioning system can reduce about 30% of annual electric power consumption of the steam humidification type outdoor air conditioning system.

비행 시뮬레이터를 이용한 조종사의 비행단계별 작업부하(Workload) 분석에 관한 연구

김기철 ( Ki Cheol Kim ),이종선 ( Jong Sun Lee ) 대한산업공학회 2000 대한산업공학회 추계학술대회논문집 Vol.2000 No.-

확장된 문형 정보를 사용하는 조건 단일화 기반의 한국어 파싱

김기철(Ki-cheol Kim) 한국통신학회 2010 韓國通信學會論文誌 Vol.35 No.12

이완 정합을 이용한 획순에 무관하게 흘려 쓴 한자의 온라인 인식 (pp.423-430)

김기철(Ki-Cheol Kim),이성환(Seong-Whan Lee) 한국정보과학회 1995 정보과학회논문지 Vol.22 No.3

본 논문에서는 인접 선분들의 관계 정보를 기반으로 이완 정합 방법을 이용하여 획순에 무관하게 흘려 쓴 한자를 온라인 인식하는 방법을 제안하였다. 본 연구에서는 평활화, 표본화, 크기 정규화 등의 전처리 과정을 거쳐 특징점을 추출하고, 8방향 코드 양자화를 통해 선분 특징을 추출하였다. 인식 시간의 단축을 위해 입력패턴의 획수에 의해 1차 대 분류하였으며, 추출한 선분 특징을 이용하여 이완 정합의 확률을 초기화하고 거리를 계산함으로써 2차 대 분류하였고, 대 분류에 의해 생성된 소수의 후보 문자만을 대상으로 이웃하는 선분들의 관계 정보를 이용하여 이완 정합을 반복함으로써 상세 분류하였다. 제안된 방법의 성능을 검증하기 위하여 교육부 지정 교육용 기초 한자 1,800자를 대상으로 다양한 획순을 갖는 정서체와 다양한 흘림체 데이타에 대하여 실험한 결과, 평균 93.5%의 인식률을 나타냄으로써 제안된 방법이 획순에 무관하게 흘려 쓴 한자의 온라인 인식에 매우 효과적임을 알 수 있었다. In this paper, we propose a stroke-order free cursive Chinese character recognition method with relaxation matching based on relational information of neighborhood line segments. In the proposed method, feature points are extracted by carrying out preprocessing steps such as smoothing, sampling, and size normalization. And then, the features of line segments are extracted by eight directional code quantization. Preliminary classification based on the number of strokes in input pattern and initial probabilities of relaxation matching is performed to reduce the recognition time. Finally, iterative relaxation matching based on relational information of neighborhood line segments is performed to discriminate some similar candidate characters. In order to demonstrate the performance of the proposed method, experiments with various kinds of stroke-order dependent characters and stroke-order free characters for 1,800 daily-used basic Chinese characters in Korea were performed, and 93.5% of correct recognition rate has been obtained. Experimental results reveal that the proposed method is very effective for stroke-order free on-line cursive Chinese character recognition.

필기체 한글의 오프라인 인식을 위한 획 정합 방법

김기철(Ki-cheol Kim),이성환(Seong-Whan Lee) 한국정보과학회 언어공학연구회 1992 한국정보과학회 언어공학연구회 학술발표 논문집 Vol.1992 No.10

원제목 반도체 클린룸용 에어와셔 외기공조시스템의 에너지소비량에 관한 실험적 연구

김기철(Ki-Cheol Kim),김형태(Hyung-Tae Kim),송근수(Gen-Soo Song),유경훈(Kyung-Hoon Yoo),손승우(Seung-Woo Son),신대건(Dae-Kun Shin),박덕준(Dug-Jun Park) 대한설비공학회 2012 설비공학 논문집 Vol.24 No.4

In recent large-scale semiconductor manufacturing clean rooms, the energy consumption of outdoor air conditioning systems to heat, humidify, cool and dehumidify incoming outdoor air represents about 45% of the total air conditioning load required to maintain a clean room environment. Therefore, the energy performance evaluation and analysis of outdoor air conditioning systems is useful for reducing the outdoor air conditioning load for a clean room. In the present study, an experiment was conducted to compare the energy consumption of outdoor air conditioning systems with a simple air washer, an exhaust air heat recovery type air washer and a DCC return water heat recovery type air washer. It was shown from the present lab-scale experiment with an outdoor air flow of 1,000 m 3 h that the exhaust air heat recovery type and DCC return water heat recovery type air washer outdoor air conditioning systems were more energy-efficient for the summer and winter operations than the simple air washer outdoor air conditi oning system and furthermore, the DCC return water heat recovery type one was the most energy-efficient in the winter operation.