방향성 결합기 입사도파로의 최적 접근각도의 광모드 과잉쏠림 현장의 조절

이현식,오범환,최철현,노현식,이승걸,박세근,이일항,Lee, Hyun-Shik,O, Beom-Hoan,Choi, Chul-Hyun,Noh, Hyun-Sik,Lee, Seung-Gol,Park, Se-Geun,Lee, El-Hang 한국광학회 2006 한국광학회지 Vol.17 No.1

We investigate a method to improve the extinction ratio of directional couplers by controlling the angle of approach to their input ports and controlling the error limit for improving the extinction ratio of the directional coupler. Although relatively large angle of approach to the input port usually causes an error in calculations made by mode propagation analysis(MPA), optimally designed angle of approach not only minimizes errors in MPA calculations but also can improve extinction ratio by precision control of coupling coefficients of optical modes. We show that abrupt changes in approaching angle, although not enough to cause modal leakage, give rise to field-profile overshooting, which degrades extinction ratio and other properties of the directional coupler. Using Beam Propagation Method (BPM) we calculate two types of input structures, linear and curved, for optimization of extinction ratio. 방향성 결합기의 소멸비 특성 개선을 위해 입사도파로의 접근각도를 조절하는 방안의 가능성과 오차한계를 살펴보았다. 입사도파로의 접근각도가 크면 단순한 모드분석 이론의 틀에 오차를 유발하게 되지만 적절하게 조절하면 오차를 극소화하면서도 입사되는 광모드의 결합계수를 미세 조절함으로써 소멸비를 개선하는 효과가 있었다. 급격한 접근각도의 설정 시에는 비록 그 각도가 작아서 유출모드(leak mode)에 의한 손실이 있기 전이더라도 광모드의 과잉쏠림(field-profile overshooting)에 의해 각종 특성의 열화가 생기기 시작하는 것을 발견하고 그 영향을 분석하였다. 진행 광모드의 변화는 BPM(Beam Propagation Method)으로 전산 모사하였으며, 직선형 및 곡선형의 두 가지 입사도파로 구조에 대해 특성변화를 비교하여 소멸비 특성을 최적화하는 조건을 얻어내었다.

프랙탈에 기초한 해저지형의 보간

이현식(Hyun-Shik Lee),박동진(Dong-Jin Park),진강규(Gang-Gyoo Jin) 한국항해항만학회 2009 한국항해항만학회지 Vol.33 No.6

저해상도 3D 해저 디지털 지형 모형(Digital terrain model: DTM)의 이미지를 컴퓨터 화면에 확대 표시할 때 데이터가 없는 픽셀은 인위적으로 보간해서 표시할 수밖에 없다. 따라서 본 연구에서는 기존의 선형 보간법의 문제점을 개선하기 위해 저해상도 DTM으로부터 지형정보를 추출하고 이로부터 보간하는 방법을 다룬다. 이를 위해 DTM을 다수의 패치로 분할하고 프랙탈 이론 (Fractal theory)를 이용하여 프랙탈 차원을 추정하고, 추정 정보와 원래의 데이터를 근간으로 패치 지형을 Midpoint Displacement법으로 보간하고, 보간된 이미지의 국부적인 기복을 완화해 자연스런 해저지형을 만들기 위해 미디언 필터(Median filter) 를 이용한다. 가상의 프랙탈 지형 맵을 이용하여 제안된 알고리즘의 그 유효성을 검정한다. In this paper we presents an algorithm which generates its high-resolution DTM using a low-resolution DTM of the sea floor terrain and fractal theory. The fractal dimension of each patch region divided from the DTM ís extracted and then with this information and original data, each cell region in the patch ís interpolated using the midpoint displacement method and a medían filter is incorporated to generate natural and smooth sea floor surface The effectiveness of the proposed algorithm ís tested on a fractal terrain map.

김동석 연구 2 - 순수문학으로부터 민족문학으로의 도정

이현식(Lee, Hyun-Shik) 인천대학교 인천학연구원 2003 인천학연구 Vol.2 No.1

Kim, Dong-suk was literary critic who was born in Incheon. This thesis is study on Kim's criticism. He proceeded to the circle of Korean literature after Korean liberation, in 1945. He had a mental freedom because he had no connection with pro-Japanese literature. Directly after liberation, Kim advocated Sunsumunhak(pure literature). He thought that literary men should have not take part in vulgar situation. But He insisted that literary men should watch such a situation. Under this context, he advocated Sunsumunhak. And in 1946 he insisted on establishment of Minjokmunhak(Korean national literature). He thought that it needed liquidation of Japanese imperialism & feudalism in order to establish Korean national literature. Kim realized his thoughts through his essay & criticism. Kim attached importance to objective recognition about actuality. He was taught this thinking by Matthew Arnold's criticism. He think literary criticism is a criticism on life. He went to north Korea just before Korean war, avoiding of suppression on ideology. But he lives enthusiastically as a literary critic in the period of Korean liberation.

다양한 산업 환경 적용용 LED 투광등 개발

이현식(Hyun-Shik Lee),옥영석(Young-Seck Ock),변기식(Gi-Sig Byun) 대한전기학회 2013 대한전기학회 학술대회 논문집 Vol.2013 No.10

In vitro와 in vivo에서 라이코펜이 EPCR 탈락에 미치는 영향

유하영(Hayoung Yoo),이현식(Hyun-Shik Lee),이원화(Wonhwa Lee),배종섭(Jong-Sup Bae) 한국생명과학회 2013 생명과학회지 Vol.23 No.5

내피세포 단백질 C 수용체(EPCR)가 트롬빈-트롬보모듈린 복합체에 의한 단백질 C (PC) 활성 증가에 중요한 역할을 한다. EPCR의 활성은 ecodomain의 분열과 수용성 단백질(sEPCR)로 분비함으로써 현저하게 변화한다. EPCR의 탈락은 tumor necrosis factor-α converting enzyme (TACE)에 의해 매개된다. 토마토에서 발견된 라이코펜은 항산화 효과, 항암 효과, 항염증 효과를 가지고 있다. 그러나 EPCR 탈락에서의 라이코펜의 효과는 알려지지 않았다. 우리는 라이코펜이 PMA, TNF-α, IL-1β와 CLP에 의해 유도된 EPCR 탈락에 미치는 영향을 연구했다. 그 결과, 라이코펜은 TACE의 발현을 억제시켜 PMA, TNF-α, IL-1β와 CLP에 의해 매개된 EPCR 탈락을 저해함을 보여준다. 또한 라이코펜은 PMA가 유발한 p38, ERK1/2, JNK의 인산화를 감소시켰다. 이러한 결과를 토대로, 라이코펜은 EPCR 탈락의 저해를 통해 다양한 중증 혈관 염증 질병 치료를 위한 후보 물질이 될 수 있을 것이다. Endothelial protein C receptor (EPCR) plays a pivotal role in augmenting Protein C activation through the thrombin-thrombomodulin complex. EPCR activity is markedly changed by ectodomain cleavage and released as the soluble protein (sEPCR). EPCR shedding is mediated by tumor necrosis factor-α converting enzyme (TACE). Lycopene found in tomatoes and tomato products has anti-oxidant, anti- cancer and anti-inflammatory effects. However, little is known about the effects of lycopene on EPCR shedding. We investigated this issue by monitoring the effects of lycopene on the phorbol- 12-myristate 13-acetate (PMA), tumor necrosis factor (TNF)-α, interleukin (IL)-1β and on the cecal ligation and puncture (CLP)-mediated EPCR shedding. Data showed that lycopene potently inhibited the PMA, TNF-α, IL-1β and CLP-induced EPCR shedding by suppressing TACE expression. Furthermore, lycopene reduced PMA-stimulated phosphorylation of p38, extracellular regulated kinases (ERK) 1/2 and c-Jun N-terminal kinase (JNK). Given these results, lycopene should be viewed as a candidate therapeutic agent for the treatment of various severe vascular inflammatory diseases via inhibition of the EPCR shedding.

오배자 추출물의 Acetylcholinesterase 저해 및 항산화 활성 평가

배종섭 ( Jong Sup Bae ),이현식 ( Hyun Shik Lee ),이하영 ( Ha Yeong Lee ),유병혁 ( Byung Hyuk Yoo ),김태완 ( Tae Wan Kim ),김용한 ( Yong Han Kim ),김태훈 ( Tae Hoon Kim ) 한국식품저장유통학회(구 한국농산물저장유통학회) 2012 한국식품저장유통학회지 Vol.19 No.5

Antioxidant capacity and acetylcholinesterase (AChE) inhibitory activity of the aqueous methanolic extract of Rhus javanica were investigated in vitro. The antioxidant properties was measured by radical scavenging assays using DPPH and ABTS+ radicals. The AChE inhibitory efficacy of R. javanica was tested by Ellman`s assay and the total phenolic content was determined using a spectrophotometric method. All tested samples showed a dose-dependent AChE inhibitory and radical scavenging activities. In particularly, ethyl acetate (EtOAc)-soluble portion from the methanolic extract of R. javanica showed significantly higher inhibitory activity than other organic solvent soluble-portions in an AChE and radical scavenging assay systems. These results suggest that R. javanica may be possess potential benefits which might be useful in development of antioxidant and anti-alzheimer`s disease ingredient.

PPGA를 이용한 이산시간 시스템의 파라미터 추정

신명호(Myung-Ho Shin),권봉재(Bong-Jea Kwon),이현식(Hyun-Shik Lee),진강규(Gang-Gyoo Jin) 한국마린엔지니어링학회 2004 한국마린엔지니어링학회 학술대회 논문집 Vol.2004 No.-

This paper presents a scheme for estimating parameters of discrete-time systems, based on the model adjustment technique and the genetic algorithm technique. To obtain a good solution with considerably small effort, a pseudo parallel genetic algorithm(PPGA) based on both the migration model and the ring topology is used. The performance of the proposed algorithm is demonstrated through test problems.

2자유도 PID 제어기의 RCGA기반 동조

황승욱(Seung-Wook Hwang),송세훈(Se-Hoon Song),김정근(Jung-Keun Kim),이윤형(Yun-Hyung Lee),이현식(Hyun-Shik Lee),진강규(Gang-Gyoo Jin) 제어로봇시스템학회 2008 제어·로봇·시스템학회 논문지 Vol.14 No.9

The conventional PID controller has been widely employed in industry. However, the PID controller with one degree of freedom(DOF) can not optimize both set-point tracking response and disturbance rejection response at the same time. In order to solve this problem, a few types of 2DOF PID controllers have been suggested. In this paper, a tuning formula for a 2DOF PID controller is presented. The optimal parameter sets of the 2DOF PID controller are determined based on the first-order plus time delay process and a real-coded genetic algorithm(RCGA) such that the ITAE performance criterion is minimized. The tuning rule is then addressed using calculated parameter sets and another RCGA. A set of simulation works are carried out on three processes with time delay to verify the effectiveness of the proposed rule.

行刑作業의 敎育的 考察

李鉉湜 全北大學校 1980 論文集 Vol.22 No.-

Prison Labour means the obligatory work which execution authorities impose on prisoners. Being managed by Contracts, private business is ruled by Labour Law. But Prison Labour is not ruled by Labour Law because it is acted by compulsory power. The aim of execution is what make prisoner good-natured man. Accordingly Prison Labour Should be focused on the enlightenment of prisoner. This thesis was developed its course according to the following items.

常溫重合 레진의 混合時間 差異에 따른 成描의 齒髓反應에 關한 實驗的 硏究

이현식,우이형,박남수 慶熙大學校 齒科大學 1989 慶熙齒大論文集 Vol.11 No.-

It is considered that self-curing resin will induce a little pulpal irritation, if mixing time is insufficient. So this study was designed to compare four different conditions between control group and three experimental groups. Canine teeth of 20 cats used, and class V cavities were prepared on maxillary canine of cats. Control group was filled with zone and other experimental groups were filled with zone after the application of the self-curing resin. Animals of the experimental and control group were sacrified at 3 days, 1, 2, 3, 4 weeks after the experiment. The finding lead to the following conclusions: 1. Odontoblasts of first and third experimental groups were condensed irregularly and were changed at early stage, and reapir was delayed. 2. Odontoblasts of second experimental group were condensed slightly but, histologic repair was appeared at 4 weeks after the experiment. 3. In all groups, the damaged odontoblastic cell layer were eventually disappeared at 4 weeks after the experiment.