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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.
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.
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.
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.
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.
운동에너지 탄과 적재포탄에 따른 전투시스템 내부에서의 순간화재발생에 대한 전산해석
이승철,전우철,이해평,이헌주,Lee, Seung-Chul,Jeon, Woo-Chul,Lee, Hae-Pyeong,Lee, Heon-Joo 한국군사과학기술학회 2013 한국군사과학기술학회지 Vol.16 No.6
In this paper, numerical analysis was performed about whether the flash fire of loaded shells breaks out in the virtual combat vehicle according to sorts of the kinetic energy ammunition as the preceding research for vulnerability analysis inside the combat system by an external threaty ammunition. In this simulation, Autodyn program was used and the Lee-Tarver ignition and growth model was used to determine the flash fire outbreak. In this study, the kinetic energy ammunition was set of type A and type B in two kinds and the loaded shells was set of COMPB, TNT, PBX9404 and ANB. As a result, TNT and PBX9404 have much higher flash fire probability than COMPB in high explosive, ANB has very low flash fire probability.
인공신경망을 이용한 VVVF-유도전동기 시스템의 실시간 운전효율 최적제어
이승철,최익,권순학,최주엽,송중호,Lee, Seung-Chul,Choy, Ick,Kwon, Soon-Hak,Choi, Ju-Yeop,Song, Joong-Ho 전력전자학회 1999 전력전자학회 논문지 Vol.4 No.2
최적효율제어를 통한 유도전동기의 효율향상은 에너지 절감측면에서 매우 중요하며 인공신경망을 사용하면 시스템의 특성이 충분히 해석되지 않은 상태에서도 우수한 제어특성을 얻을 수 있다. 본 논문은 유도전동기 구동시스템에서 최적 슬립주파수를 추종하는 실시간 인공신경망 회로를 구성하여 운전효율을 최적화하는 제어방법을 제안한다. 제안된 최적 효율제어기는 인공신경망 제어기에 의해 시스템의 비선형성을 포함하여 전동기의 내부손실이 최소가 되는 운전점을 추종한다. 시뮬레이션과 실험을 통하여 기존의 일정v/f 방식에 비하여 고속 경부하시 경제성 있는 에너지 절감효과를 충분히 확보할 수 있었다. On-line efficiency optimization control of an induction motor drive using neural network is important from the v viewpoints of energy saving and controlling a nonlinear system whose charact81istics are not fully known. This paper p presents a neural networklongleftarrowbased on-line efficiency optimization control for an induction motor drive, which adopts an optimal slip an밍J.lar frequency control. In the proposed scheme, a neuro-controller provides minimal loss operating point i in the whole range of the measured input power. Both simulation and experimental results show that a considerable e energy saving is achieved compared with the conventional constant vlf ratio operation.
긴장재배치에 따른 PT 이방향 슬래브의 거동에 대한 해석적 연구
이승철,이영학,Lee. Seung-Chul,Lee. Young-Hak 한국방재학회 2011 한국방재학회논문집 Vol.11 No.6
본 논문에서는 이방향 포스트텐션 슬래브의 다양한 텐던의 배치에 따른 효과를 분석하기 위해서 유한요소법에 기반한 해석적 연구를 수행하였다. 등분포된 텐던의 배치에서부터 기둥의 중심선에 인접하게 배치되는 형태까지 연구범위를 설정하였고, 유한요소해석 상용 프로그램인 SAP에서 제공하는 휨-평면 요소를 사용하여 모델링을 하였다. 텐던 프로파일에 근거한 등가하중을 텐던 배치에 따라서 적용하였으며, 사용 하중 상태에서의 처짐과 순수 모멘트를 결정하기 위해 텐던에 대한 등가하중에 일반적인 중력하중이 부가되었다. 또한 해석 결과와 실험결과를 비교 분석하였다. In this paper, the FE analysis results are presented to evaluate the effects of various tendon layouts on the performance of post-tensioned concrete two-way slab systems. Various arrangements from uniform cable layouts to closely banded arrangements adjacent to column centerlines are considered. The slab is modeled using plate-bending elements in the software package SAP. Equivalent loads based on cable profiles are applied to the slab according to the tendon layout. Moment fields and deflected shapes are compared for the various tendon patterns. Gravity loads are applied in the usual way and superimposed on the results from the equivalent tendon loads to determine net moments and deflections at service load levels. In addition to a study of tendon layouts, the finite-element model is compared with experimental results.