직렬 연결 위상 천이 장주기 격자의 특성과 초기 커플링 세기 효과에 관한 연구

김민성,한영근,Kim, Min-Sung,Han, Young-Geun 한국광학회 2006 한국광학회지 Vol.17 No.1

위상 천이 광섬유 격자를 직렬로 연결하였을 경우 파장 투과 특성에 대해서 이론 및 실험적으로 분석하였다. $\pi$만큼의 위상 천이가 유도된 장주기 격자의 파장 투과 특성은 직렬 연결되는 위상 천이 장주기 격자의 개수에 따라 변화하며 개수를 증가시킴에 따라 파장 투과 대역폭을 증가시킬 수 있다. 또한 $\pi$-위상 천이 장주기 격자의 파장 투과 대역폭은 격자 길이를 변화시킴에 따라 조절할 수 있으며 길이가 다른 두 개의 $\pi$-위상 천이 장주기 격자를 직렬로 연결하면 파장 투과 및 제거 대역폭을 조절할 수 있다 그리고 장주기 격자의 반을 UV에 노출 시켰을 때, 위상 천이 장주기 격자가 형성됨을 관찰하였고, 초기 커플링 세기에 따라 격자의 형성이 달라짐과 인가되는 인상 천이 크기에 따라서 다양한 형태의 위상 천이 장주기 광섬유 격자의 투과 특성을 나타내었다. The transmission characteristics of multiply cascaded phase-shifted long-period fiber gratings(LPFGs) were investigated theo-retically and experimentally. Their passband can be changed by increasing the number of p-shifted LPFGs. When two p-shifted LPFGs with different grating lengths are cascaded in series, the bandwidth of the rejection band and passband can be controlled by the pristine characteristics of two gratings. We also investigate the transmission characteristics of phase-shifted LPFG by exposing the half of LPFG region to UV laser. The transmission characteristics strongly depend on the initial coupling strength of the LPFG.

플래시를 이용한 웹기반 수업에 관한 고찰

김민성,박성훈,Kim, Min-Sung,Park, Sung-Hoon 한국디지털콘텐츠학회 2010 한국디지털콘텐츠학회논문지 Vol.11 No.2

웹기반 교육은 학습자 중심의 학습과 협동학습을 촉진시킬 수 있는 새로운 수업도구로서 기존의 획일화된 교수-학습 방식에서 탈피하여 새로운 교수모형에 대한 연구로 발전되고 있다. 강력한 웹 저작도구중 하나인 플래시를 사용하면 컴퓨터 그래픽, 애니메이션과 사운드 그리고 동영상 등의 활용으로 학습의 효과를 극대화 시킬 수 있다. 본 논문에서는 플래시를 사용한 교육 자료의 개발 및 배포와 효율적인 웹기반 수업에 대하여 고찰하고자 한다. Web-based instruction is being developed as a new study model getting out of the traditional standardized education method. It is a new education tool which promotes learner-centered and cooperative study. Flash, as one of the most powerful web authoring tool can maximize the effectiveness of learning using computer graphic, animation, sounds and video. In this paper, we will look at developing and distributing education materials using flash and the efficient web-based instructions.

Al-Zn 혼합물의 열 증발을 이용한 ZnO 결정의 합성에서 결정의 형상에 미치는 합성 온도와 시간의 영향

김민성,Kim, Min-Sung 한국재료학회 2015 한국재료학회지 Vol.25 No.6

ZnO micro/nanocrystals at large scale were synthesized through the thermal evaporation of Al-Zn mixtures under air atmosphere. The effect of synthetic temperature and time on the morphology of the micro/nanocrystals was examined. It was found that the temperature and time affected the morphology of the ZnO crystals. At temperatures below $900^{\circ}C$, no crystals were synthesized. At a temperature of $1000^{\circ}C$, ZnO crystals with a rod shape were synthesized. With an increase in temperature from $1000^{\circ}C$ to $1100^{\circ}C$, the morphology of the crystals changed from rod shape to wire and granular shapes. As the time increased from 2 h to 3 h at $1000^{\circ}C$, tetrapod-shaped ZnO crystals started to form. XRD patterns showed that the ZnO crystals had a hexagonal wurtzite structure. EDX analysis revealed that the ZnO crystals had high purity. It is believed that the ZnO nanowires were grown via a vapor-solid mechanism because no catalyst particles were observed at the tips of the micro/nanocrystals in the SEM images.

열린타원구멍을 통한 기이색전증이 발병 원인으로 추정되는 뇌경색 환자의 동서 협진 치험 1례

김민성,옥효준,양지연,정택수,선종주,유소정,Kim, Min-sung,Ok, Hyo-joon,Yang, Jee-yun,Jeong, Taek-su,Sun, Jong-joo,You, So-jung 대한한방내과학회 2016 大韓韓方內科學會誌 Vol.37 No.5

Objective: To evaluate the effects of integrative treatment with conventional and Korean medicine on cerebral infarction due to presumed paradoxical embolism through a patent foramen ovale. Methods: We applied acupuncture, herbal medication, western medication, and physical therapy routinely every day and applied fluid therapy provided as needed. The NIHSS, K-MBI, MRS, MMT, and MMSE-K score were determined to assess any improvement in symptoms. Results: Scores appeared to be improved for the NIHSS (9 to 5), K-MBI (94 to 100), MRS (2 to 1), MMT (2+, 4 to 4, 4), MMSE-K (24 to 26). No side effects were observed during the treatment. Conclusions: This study demonstrates that integrative treatment with conventional and Korean medicine may be an effective option for treating cerebral infarction due to a presumed paradoxical embolism through a patent foramen ovale.

한국어 연속 숫자음 전화 음성 인식에서의 오인식 유형 분석

김민성,정성윤,손종목,배건성,김상훈,Kim Min Sung,Jung Sung Yun,Son Jong Mok,Bae Keun Sung,Kim Sang Hun 대한음성학회 2003 말소리 Vol.46 No.-

Channel distortion and coarticulation effect in the Korean connected digit telephone speech make it difficult to achieve high performance of connected digit recognition in the telephone environment. In this paper, as a basic research to improve the recognition performance of Korean connected digit telephone speech, recognition error patterns are investigated and analyzed. Korean connected digit telephone speech database released by SiTEC and HTK system are used for recognition experiments. Both DWFBA and MRTCN methods are used for feature extraction and channel compensation, respectively. Experimental results are discussed with our findings.

손모양 인식기반의 경로교사와 장애물 인식이 가능한 자율보행 다족로봇 시스템

김민성,정우원,권배근,강동중,Kim, Min-Sung,Jeong, Woo-Won,Kwan, Bae-Guen,Kang, Dong-Joong 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.8

영상카메라와 무선통신 기능을 탑재한 손모양 및 장애물 인식이 가능한 다족 로봇을 독자적으로 설계 및 제작하고 제작한 로봇에 최적화된 보행패턴 알고리즘을 개발하여 적용하였다. 영상센서의 입력화상에 대해 하프변환 (Hough Transform)을 사용하여 물체의 외곽선을 추출하여 장애물을 인식하여 회피하는 실시간 자율보행이 가능한 알고리즘을 개발하였다. 로봇의 목표물 및 목적지 설정을 위하여 미리 학습시킨 피부색의 평균값과 입력영상의 확률거리(Mahalanobis Distance)를 산출하여 손 영역을 검출하고 손가락 개수에 따라 로봇의 명령 제어가 가능하도록 하였다. 장애물 및 손모양 인식에 따른 다족 자율 보행 로봇의 수행 실험 평균 결과 약 96%의 장애물 인식률과 94%의 손 모양 인식률을 보였다. In this paper, multi-legged robot was designed and produced using stable walking pattern algorithm. The robot had embedded camera and wireless communication function and it is possible to recognize both hand posture and obstacles. The algorithm decided moving paths, and recognized and avoided obstacles through Hough Transform using Edge Detection of inputed image from image sensor. The robot can be controlled by hand posture using Mahalanobis Distance and average value of skin's color pixel, which is previously learned in order to decide the destination. The developed system has shown obstacle detection rate of 96% and hand posture recognition rate of 94%.

pH 나노센서로의 응용을 위한 UV-가교 P4VP 박막에 고정한 금 나노입자의 특성

김민성,정연태,Kim, Min-Sung,Jeong, Yeon-Tae 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.11

In this report, we describe the use of gold nanoparticles (AuNPs) immobilized on pH. responsive, cross-linked poly(4-vinylpyridine) (P4VP) thin films, as a potential application for pH nanosensors. The methodology is based on the variation in surface plasmon resonance of immobilized AuNPs with changing the interparticle distances, caused by the swelling/deswelling of the pH responsive P4VP polymer films. The change in optical properties of the immobilized AuNPs in response to the pH of surrounding media was investigated by a simple yet powerful tool; UV-vis absorption spectroscopy. The swelling of the P4VP chains at pH 2 causes an increase in the interparticle distances of immobilized AUNPS ($\sim20nm$) and hence leads to a blue shift of 48 nm in their surface plasmon resonance band peak. On the other hand, when the surrounding media was altered from pH 2 to 10, a red shift of absorption maxima was observed. The changes were rapid, and the effect was reversible. This system could prove to be useful in fabricating nanosensors for detecting the pH or pH changes of surrounding aqueous medium.

금속산화물 복합분말의 동결건조 및 수소분위기 환원처리에 의한 Cu-Sn 다공체 제조

김민성,유호석,오승탁,현창용,Kim, Min-Sung,Yoo, Ho-Suk,Oh, Sung-Tag,Hyun, Chang-Yong 한국재료학회 2013 한국재료학회지 Vol.23 No.12

Freeze drying of a porous Cu-Sn alloy with unidirectionally aligned pore channels was accomplished by using a composite powder of CuO-$SnO_2$ and camphene. Camphene slurries with CuO-$SnO_2$ content of 3, 5 and 10 vol% were prepared by mixing with a small amount of dispersant at $50^{\circ}C$. Freezing of a slurry was done at $-25^{\circ}C$ while the growth direction of the camphene was unidirectionally controlled. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green bodies were hydrogen-reduced at $650^{\circ}C$ and then were sintered at $650^{\circ}C$ and $750^{\circ}C$ for 1 h. XRD analysis revealed that the CuO-$SnO_2$ powder was completely converted to Cu-Sn alloy without any reaction phases. The sintered samples showed large pores with an average size of above $100{\mu}m$ which were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores. The size of the large pores decreased with increasing CuO-$SnO_2$ content due to the change of the degree of powder rearrangement in the slurry. The size of the small pores decreased with increase of the sintering temperature from $650^{\circ}C$ to $750^{\circ}C$, while that of the large pores was unchanged. These results suggest that a porous alloy body with aligned large pores can be fabricated by a freeze-drying and hydrogen reduction process using oxide powders.

표준 단일모드 광섬유와 EDFA를 이용한 10 Gb/s 40 파장다중 채널 신호의 3000 km 전송에서 분산 보상 맵 최적화와 분산 기울기 불일치 영향

김민성,최보훈,Kim Min-Sung,Choi Bo-Hun 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.1a

표준 단일모드 광섬유를 전송선으로 사용하고, Raman 증폭기 없이 EDFA 증폭기만을 사용하여, 각 채널당 10 Gb/s의 파장다중화된 40개 채널신호들을 장거리 전송하는 경제적인 광 링크를 구성한 뒤, 이 링크의 전송 성능 최적화를 위해 분산 맵 구조의 차이에 따른 성능 차이를 분석하였다. 이 링크의 분산 맵은 전치분산보상, 구간분산보상 그리고 후치분산보상으로 나누어지는데 이들의 다양한 조합을 통해 15 가지의 다양한 분산 맵들을 구성한 뒤 각각의 경우를 분석하여 링크 성능을 크게 향상시키는 최적화된 분산맵 구조를 구하였다. 또한, 이 최적화된 분산 조건이, 단일모드 광섬유와 분산보상 광섬유가 가지는 파장에 따른 분산 기울기의 불일치로 인해 받게 되는 영향을 조사하였고, 이 영향이 링크의 성능에 미치는 효과가 무시될 수 있는 분산 기울기의 허용 가능한 불일치 범위를 구했다. We have studied the dispersion properties of a 40 channel x 10 Gbit/s wavelength division multiplexer(WDM) transmission link using standard single mode fiber with all EDFA amplification over 30 x 100 km spans. The dispersion map of the link was investigated by adding fiber sections with positive or negative dispersion at the transmitter, within each amplifier span, and at the receiver. Optimum combinations of these dispersive fiber lengths were attained to significantly enhance the overall transmission performance.

참옻 추출물의 MCF-7 인체 유방암 세포에서 증식 억제효과

김민성,안원근,이장천,Kim, Min Sung,An, Won Gun,Lee, Jang Cheon 대한한의학방제학회 2016 大韓韓醫學方劑學會誌 Vol.24 No.4

Objectives : The purpose of this study was to investigate the anti-cancer effects of extract of Rhus verniciflua Stokes (RVS) in human breast cancer cell lines. Methods : In cultured human breast cancer MCF-7 cells, we investigated growth inhibitory effect of RVS. MCF-7 cells were cultured with various concentrations (0, 200, 300, and 400 ug/ml) of RVS at $37^{\circ}C$ for 24 h. We performed CCK-8 assay and flow cytometry for detection of Annexin V-PI staining. Results : As a result, RVS inhibits the cell growth and induction of apoptosis in dose dependent manner in MCF-7 breast cancer cells. Conclusion : RVS has anti-cancer activities and induced apoptosis in human breast cancer MCF-7 cells. Therefore we suggest that RVS can use as a novel class of anti-cancer drugs.