운동에너지 탄에 따른 전투시스템 내의 순간화재발생에 대한 해석적 연구

이승철(Lee Seung-Chul),전우철(Jeon Woo-Chul),이해평(Lee Hae-Pyeong),이헌주(Lee Heon-Joo),이창현(Lee Chang-Hyun) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7

본 연구는 외부 위협탄에 의한 전투시스템의 취약성을 분석하기 위한 선행연구로써, 운동에너지 탄의 종류에 따른 가상의 전투차량 내부에 적재포탄에서 순간화재발생 여부에 대한 전산해석을 수행하였다. 본 해석은 Autodyn 프로그램을 사용하였으며 순간화재발생을 판단하기 위해 Lee-Tarver ignition and growth model을 이용하였다. 본 계산에서 운동에너지 탄은 type A와 type B 두 가지로 설정하였고, 고폭탄은 COMPB, TNT 및 PBX9404를 설정하였다. 전산해석 결과, 고폭탄의 재질이 TNT와 PBX9404가 COMPB 재질보다 순간화재발생 확률이 상당히 높음을 알 수 있고 type B의 운동에너지 탄이 type A 보다 순간화재발생 확률이 다소 높음을 알 수 있었다.

태양광-풍력 복합발전시스템의 경제적 운용을 위한 최적 용량 산정에 관한 연구

이승철,문운철,권병국,김종환,Lee, Seung-Chul,Moon, Un-Chul,Kwon, Byeong-Gook,Kim, Jong-Hwan 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.3

본 논문에서는 누진전력요금제도 하에서 주어진 부하에 대해 최적의 계통연계형 태양광-풍력 복합발전시스템 용량을 산정하는 기법에 대하여 논한다 일사량 및 풍속의 확률밀도함수를 이용해 복합발전시스템 발전량의 기대치를 구하고, 총수명가 분석법에 기초하여 월별 발전단가를 산정하는 기법과 함께 월사용전력량이 증가함에 따라 전력요금이 급속히 증가하는 누진전력요금구조 하에서 전체 월 전력비용을 최소로 하기 위한 설비용량산정기법에 대하여 논한다. 제안한 기법의 적용가능성을 검토하기 위하여 실제 수도권의 기상데이터를 근거로 하여 본 대학에 설치된 prototype 복합발전시스템을 이용하여 실증연구를 수행하였다. In this paper, a technique that estimate the optimal capacity of the solar-wind hybrid power system for minimizing the total monthly electric power expenses is presented. The hybrid power system is assumed to be operated in connection with the utility power system and electric bill be paid for the power not covered by the hybrid system generation. Monthly generation cost is estimated based on total life-cycle cost analysis. The monthly utility power bill is assumed to be increased quadratically in proportion with the net utility power consumption which is the difference between the total monthly load minus the hybrid system generations. Test results demonstrate applications potential of the proposed technique.

디지털 비디오 부호화에서의 고속 움직임 추정을 위한 저복잡도 알고리즘

이승철,김민기,정제창,Lee, Seung-Chul,Kim, Min-Ki,Jeong, Je-Chang 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.12C

In video standards such as MPEG-1/2/4 and H.264/AVC, motion estimation / compensation(ME/MC) process causes the most encoding complexity of video encoder. The full search method, which is used in general video codecs, exhausts much encoding time because it compares current macroblock with those at all positions within search window for searching a matched block. For the alleviation of this problem, the fast search methods such as TSS, NTSS, DS and HEXBS are exploited at first. Thereafter, DS based MVFAST, PMVFAST, MAS and FAME, which utilize temporal or spacial correlation characteristics of motion vectors, are developed. But there remain the problems of image quality degradation and algorithm complexity increase. In this thesis, the proposed algorithm maximizes search speed and minimizes the degradation of image quality by determining initial search point correctly and using simple one-dimension search patterns considering motion characteristics of each frame. MPEG-1/2/4, H.264/AVC와 같은 영상압축표준에서 사용되는 부호화 기술 중 움직임 추정 및 보상은 부호기의 복잡도에 가장 큰 영향을 끼친다. 영상 코덱에서 일반적으로 사용되는 전역탐색(Full Search) 방식은 최적의 정합블록을 찾기 위해 탐색 영역내의 모든 위치에서 SAD값을 비교하기 때문에 부호화 시간을 다량으로 소비하게 된다. 이런 문제를 개선하기 위해 초기에는 TSS, NTSS, DS, HEXBS 등 다양한 형태의 탐색 패턴을 활용한 고속 움직임 탐색 기법들이 개발되었고, 이후에는 움직임 벡터의 시 공간적 상관도를 이용한 DS기반의 MVFAST, PMVFAST, MAS, FAME 등이 개발되었다. 하지만 부정확한 움직임 벡터 탐색으로 인해 화질이 열화되는 문제와 알고리즘의 복잡도가 높아지는 문제는 여전히 해결해야 할 과제로 남아있다. 본 논문에서는 움직임 벡터 탐색시작점을 보다 정확히 결정하고, 각 프레임들의 움직임 특성을 고려한 단순화된 일차원 탐색 패턴들을 사용하여 탐색속도를 극대화하고 화질열화를 최소화시키는 알고리즘을 제안한다.

산소과다가 임신에 미치는 영향에 관한 실험적 연구

이승철,조수헌,안형식,윤덕로,Lee, Seung-Chul,Cho, Soo-Hun,Ahn, Hyeong-Sik,Yun, Dork-Ro 대한예방의학회 1989 Journal of Preventive Medicine and Public Health Vol.22 No.1

The adverse effect of diving on the fetus may extend beyond n gestational process and outcome. Primiparous Sprague-Dawley rats were assigned to one of ten exposure schedules during gestatred $PO_2$ level, the following question about the effect of exposing a pregnant female to high partial pressure of inspired oxygen has been raised. 'What effect does an increased maternal $PIO_2$ have on fetal arterial $PO_2$ and therefore on possible fetal oxygen poisoning?' This study was carried out to observe the effects of maternal hyperoxia on gestational process and outcome. Primiparous Sprague-Dawley rats were assigned to one of ten exposure schedules during gestation. The treatment groups were subjected to either the high concentration of oxygen, or the high atmospheric pressure. On day 21 of gestation, laparotomy was performed to examine for number and distribution of implantations and live and resorbing embryos. Fetuses were weighed, and examined for gross malformations. Subsequently, they were fixed, measured in physical parameters, and examined for visceral anomalies. Minor visceral anomalies and anatomical variation was not found. Similarily, there were no significant differences when number of resorptions, mean fetal weights, pregnancy interruption rate were compared by analysis of variance. These results indicate that exposing rats to oxygen at increased atmospheric pressure doese not affect fetal health or survival.

Fabrication of Tin(IV) Oxide Film by Sol-gel Method

이승철,이재호,김영환,Lee Seung-Chul,Lee Jae-Ho,Kim Young-Hwan The Korean Electrochemical Society 2000 한국전기화학회지 Vol.3 No.1

태양전지의 전극 기판으로 사용되는 전도성 투명 산화주석 박막의 제조 방법에 대하여 연구하였다. 졸겔법을 이용하여 산화 주석 박막을 제조하는 경우에 저가의 공정으로 대면적의 박막을 얻을 수 있는 장점이 있다. 본 연구에서는 공정 조건의 확립과 전구체의 설정에 중점을 두었다. 전구체 용액을 isopropyl 알코올에 tin isopropoxide를 용해한 용액을 사용하였으며 수화 반응을 억제하기 위하여 triethanolamine(TEA)을 첨가하였다. Corning유리 위에 spinning과 dipping방법을 이용하여 코팅을 하였으며 이후 열처리하여 최종 산화주석 박막을 제조하였다. 이렇게 제조된 박막은 가시광선 영역에서 $90\%$ 이상의 투과도를 보였으며 $0.01\Omega{\cdot}cm$ 이하의 비저항을 나타냈다 Transparent conducting tin (IV) oxide thin films have been studied and developed for the electrode materials of solar cell substrate. Fabrication of tin oxide thin films by sol-gel method is process development of lower cost photovoltaic solar cell system. The research is focused on the establishment of process conditions and development of precursor. The precursor solution was made of tin isopropoxide dissolved in isopropyl alcohol. The hydrolysis rate was controlled by addition of triethanolamine. Dip and spin coating technique were applied to coat tin oxide on borosilicate glass. The resistivity of the thin film was lower than 0.01-cm and the transmittance is higher than $90\%$ in a visible range.

AlTiN코팅공구를 사용한 플라스틱금형강의 기계가공성 평가

이승철,조규재,Lee, Seung-Chul,Cho, Gyu-Jae 한국생산제조학회 2009 한국생산제조학회지 Vol.25 No.2

In this research, KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the $\Phi$ 8mm cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, slope of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, and surface roughness were studied. The cutting component force showed a good agreement better the up ward direction than the down ward direction under all experimental conditions. In case of the condition per the material shape, it was lessen when the tool have larger angle because the average effective diameter of the tool is larger. The surface roughness showed good condition in case of the up ward than the down ward direction. And, in the 3rd layer of AlTiN coating, it showed the most suitable condition.

에탄의 산화성 탈수소화를 위한 Boron 산화물이 첨가된 알루미나 촉매의 최적 제조조건

이승철,유의연,선우창신 ( Seung Chul Lee,Eui Yeon Yu,Chang Shin Sunwoo ) 한국화학공학회 1995 화학공학의이론과응용 Vol.1 No.2

도로터널 임계풍속 산정에 격자개수 및 화원의 크기와 위치가 미치는 영향

이승철,김상일,Lee, Seung-Chul,Kim, Sang-Il 한국터널지하공간학회 2012 한국터널지하공간학회논문집 Vol.14 No.3

본 연구에서는 도로터널 내 화재 시 임계풍속 산정을 위해 3차원 전산유체역학 기법을 이용하여 격자수, 그리고 화원의 크기와 위치에 따라 그 결과를 비교 분석하였다. 본 대상터널에서 1차원 식으로 산출된 임계풍속은 터널 높이 대신 수력지름을 적용한 경우 2.22 m/s로 산정되었다. 임계풍속 2.25 m/s를 적용하여 격자수에 따른 6가지 수치해석 결과, 격자수에 따라 역류의 위치와 온도, CO 농도 값이 상이하게 나타났으며, 본 대상터널의 경우는 약 84만개 격자수를 사용한 case 1이 적절한 격자임을 알 수 있었다. 또한 화원의 크기와 위치에 따른 수치해석 결과, 화원의 크기와 위치에 따라 상이한 기류분포, 온도분포 및 CO농도분포를 나타내어 임계풍속에 영향을 미친다는 것을 확인했다. 이것은 열교환 면적과 위치에 기인된다고 판단된다. 향후 실제 실험결과와 상세히 비교하여 3차원 수치해석의 격자 의존성과 화원의 위치 및 크기를 반드시 확인해야 할 것으로 판단된다. This study conducted comparative analysis to estimate critical velocity in tunnel fire under variation of grid number and the location and size of the fire source using three-dimensional computational fluid dynamics. In the target tunnel, by one-dimensional way, the calculated critical velocity in the tunnel, 2.22 m/s was estimated, if appling hydraulic diameter, instead of the tunnel height. According to six numerical analysis, each grid number has different position, temperature, and CO concentration of back-layering. In the case of the subject, the case 1 with 0.84 million grid was found to be the most ideal. According to the location and size of the fire source, after three cases for three-dimensional numerical analysis was performed, it is resulted that the location and size of the fire source affect the critical velocity, because air velocity distribution, temperature distribution and CO concentration distribution showed different each case. This is due to the difference of heat exchange area and locations. Therefore, it is necessary to decide appropriate grid number, and the location and size of the fire source for processing techniques through comparison with actual experiment results and three-dimensional analysis.

잎담배 품질평가방법의 문제점 및 전망

이승철,류명현,한철수,반유선,Lee, Seung-Chul,Ryu, Myung-Hyun,Han, Chul-Soo,Ban, Yu-Son 한국작물학회 1988 Korean journal of crop science Vol.33 No.S

This paper comprised a review of published literature dealing with the evaluation of tobacco quality and usability. Evaluation of tobacco quality and usability seems to be difficult not only due to our inability to define them in simple and easily measurable term but also due to their relations to the profitability of tobacco companies and safety of comsumers. Chemical constituents and smoking taste and aroma of the tobacco represent the underlying basis for tobacco quality: however, tobacco is still purchased upon its physical appearance. Grade and value system is very convenient for evaluating the tobacco quality, if the system is based on the triangular relationship of physical appearance, chemical and smoking properties of tobacco, and also based on intrinsic quality of the tobacco independent of external influences. Grade and value system for tobacco in Korea is thought to be influenced by external factors besides intrinsic quality. Therefore, we have to concern new systems that could be supplement to, or replacement for currently available grade and value system.

멀티 홉 통신을 기반한 화학 사고 대응 실시간 원격 모니터링 시스템

이승철,김남호,Lee, Seung-Chul,Kim, Nam-Ho 한국정보통신학회 2022 한국정보통신학회논문지 Vol.26 No.11

Recently, the safety of chemical substances has gained attention due to incidents occurring in petrochemical industrial complexes, such as gas leaks and fires. In particular, industrial complexes in Ulsan and Yeosu (South Korea) are valuable as they significantly contribute to the petrochemical industry, but accidents may occur due to chemical leakage. Therefore, in this study, sensor nodes are configured at an interval of 20 [m] based on outdoor facilities standards to respond to chemical accidents, and exposure consideration of 8 h (TWA) and 15 min (STEL) are proposed in TLVs. The proposed system pre-processes data collected in multi-hop communication at a cycle of 0.6-0.75 [s] using Python and stores it in the MySQL database through SQL and a real-time remote monitoring system that updates the stored data once every 5 s is implemented by linking MySQL and Grafana.