인간포배기 배아의 효과적인 유리화 동결법의 개발을 위한 연구

이상민,이주희,이상원,이승민,윤산현,임진호,박흠대,이성구,Lee, Sang-Min,Lee, Ju-Hee,Lee, Sang-Won,Lee, Seoung-Min,Yoon, San-Hyun,Lim, Jin-Ho,Park, Huem-Dai,Lee, Seong-Goo 대한생식의학회 2003 Clinical and Experimental Reproductive Medicine Vol.30 No.3

Objective: The purpose of this study was to evaluate the survival rate of vitrified blastocyst according to the freezing vessels, equilibration time in cryoprotectant and artificial dehydration method. Methods: Human blastocysts were vitrified after loading onto the plastic straw, open-pulled straw (OPS), electron microscopy grid (EM grid) for 1.5 min or 3 min. They also were directly plunged into LN2 within 30sec. For artificial shrinkage of blastocysts, 36 gauge fine needle was pushed at the cellular junction of the trophectoderm into the blstocoele cavity until it shrank without damage of inner cell mass. Results: The survival rate of vitrified blastocysts on plastic straw, OPS, EM grid as freezing vessels were 26.7, 13.0 and 60.5%, respectively. The survival rate of EM grid was significantly higher than that of plastic straw and OPS (p<0.05). For 1.5 min equilibrium, the survival rates of early blastocyst (EB), middle blastocyst (MB) and late blastocyst (LB) were 64.4, 81.0, and 20.0% respectively. For 3 min equilibrium, the survival rates of EB, MB, and LB were 69.9, 50.0 and 57.5% respectively. The survival rates of EB and MB were significantly higher than that of LB in 1.5 min equilibrium group (p<0.05), however, the significance was not observed in 3 min equilibrium groups. In cytoplasmic shrinkage before vitrification, the survival rates of EB, MB and LB were 92.9, 100 and 75.9% respectively. The survival rate of MB was significantly higher than that of LB (p<0.05). The survival rates of vitrified blastocysts by artificial dehydration and slow-frozen blastocysts were not significantly different as 88.9 and 66.7%, respectively. Conclusion: This study showed that the vitrification of human blastocysts using EM grid and artificial dehydration is an effective method. Therefore, these methods would be an useful techniques for blastocyst cryopreservation.

파워 분배망을 고려한 디지털 회로 시스템의 설계와 분석

이상민,문규,위재경,Lee, Sang-Min,Moon, Gyu,Wee, Jae-Kyung 대한전자공학회 2004 電子工學會論文誌-SD (Semiconductor and devices) Vol.41 No.4

This paper presents the channel analysis considering power distribution network(PDN) system of PCB. For achieve the target PDN system we proposed the useful design approach for acquiring the characteristic target of power distribution network in overall frequency ranges. The proposed method is based on the hierarchical approach related to frequency ranges and the path-based equivalent circuit model to consider the interference of the current paths between the decoupling capacitors and the board through it is a lumped model for fast and easy calculation, experimental results show that the proposed model is almost as precise as the numerical analysis. The analysis of PDN system shows that although the effective inductance of package dominatly affects the power noise and the signal transfer through data channel, the board PDNs also can not be neglected for achieving the accurate channel signaling. Therefore, we must design concurrently the chip, package, and board from the initial spec design of high speed digital system. 이 논문은 PCB의 PDN(Power Distribution Network) 시스템을 고려한 채널 분석을 나타내었다. 설계자가 원하는 PDN 시스템을 설계하기 위하여, 전체 주파수 범위의 PDN이 요구하는 임피던스를 얻는 유용한 설계방법을 제안하였다. 제안된 방법은 주파수 영역과 관계된 계층적 배치 접관방식과 보트와 decoupling 커패시터 사이의 current 흐름의 간섭을 고려한 path-based equivalent 회로를 기본으로 하였다. 비록 빠르고 쉬운 계산을 위한 lumped model일지라도, 실험 결과는 제안된 모델이 numerical 분석처럼 거의 정확함을 보였다. PDN 시스텐의 분석은 패키지 인덕턴스가 파워 노이즈, 데이터 채널을 통한 신호 이동에 영향을 받는다는 것을 보여주고 있으나, 보드 PDN 또한 정확한 채널 신호를 위해 무시할 수 없다는 것을 보여준다. 따라서 설계자는 반드시 초고속 디지털 시스템의 첫 스팩 설계로부터 보드, 패키지, 칩 등을 동시에 디자인을 해야 한다.

머신러닝 기법을 활용한 낙동강 중류 지역의 Chl-a 예측 알고리즘 비교 연구(수질인자 및 수량 중심으로)

이상민,박경덕,김일규,Lee, Sang-Min,Park, Kyeong-Deok,Kim, Il-Kyu 대한상하수도학회 2020 상하수도학회지 Vol.34 No.4

In this study, we performed algorithms to predict algae of Chlorophyll-a (Chl-a). Water quality and quantity data of the middle Nakdong River area were used. At first, the correlation analysis between Chl-a and water quality and quantity data was studied. We extracted ten factors of high importance for water quality and quantity data about the two weirs. Algorithms predicted how ten factors affected Chl-a occurrence. We performed algorithms about decision tree, random forest, elastic net, gradient boosting with Python. The root mean square error (RMSE) value was used to evaluate excellent algorithms. The gradient boosting showed 10.55 of RMSE value for the Gangjeonggoryeong (GG) site and 11.43 of RMSE value for the Dalsung (DS) site. The gradient boosting algorithm showed excellent results for GG and DS sites. Prediction value for the four algorithms was also evaluated through the Receiver operating characteristic (ROC) curve and Area under curve (AUC). As a result of the evaluation, the AUC value was 0.877 at GG site and the AUC value was 0.951 at DS site. So the algorithm's ability to interpret seemed to be excellent.

BMI 시스템 기술 현황

이상민,Lee, Sang-Min 대한전자공학회 2007 전자공학회지 Vol.34 No.9

난청인을 위한 전화기 음성증폭 및 하울링 억제

이상민,Lee, Sang-Min 대한의용생체공학회 1998 의공학회지 Vol.19 No.6

일반전화기로 통화가 어려운 난청인에게 충분한 수신음량을 공급하기 위해서는 큰 증폭이 필요한데 큰 증폭은 하울링(howling)을 발생시킨다. 본 연구에서는 소리를 크게 증폭하면서 하울링을 억제하는 새로운 방법을 제안하고 이를 적용한 보청전화기를 개발하여 평가하였다. 통화수신 음성은 3개의 밴드로 나뉘어져 각각 독립적으로 증폭되어 난청인의 청력에 알맞게 적합(fitting)된다. 수신음성의 주파수는 카운터에 의하여 시간영역에서 모니터링되는데 카운터부는 비교기를 이용하여 수신 정현파를 구형파로 변환시키고 시간영역에서 구형파 수를 계수함으로써 주파수를 분석하여 하울링이 발행하는가를 판단한다. 전화기는 송수화기 구조가 결정되어 있고 송수신 주파수 범위가 제한되어 있으므로 하울링 또한 일정주파수 범위내 발생하게 된다. 계수기에 의해 하울링이 검출되면 중앙제어부는 해당대역의 증폭도를 빠르게 낮춤으로써 하울링을 억제시킨다. 시험결과 개발전화기는 하울링 없이 40dB 이상 증폭할 수 있으며 중고도 난청인의 어음인지력이 1음절어의 경우는 20%에서 60.8%로, 2음절어의 경우는 28.9%에서 78%로 향상되는 탁월한 개선 효과를 보였다. To provide sufficient sound to the hearing-impaired person(HIP) who have many difficulty in communication with others using general telephone, big amplification is needed. But big amplification can occur howling as a side effect. In this study we developed the new technique of big amplification without howling, manufactured and estimated the new hearing aid telephone. Telephone speech is divided to three frequency band, amplified respectively and fitted to HIP's hearing ability. The telephone speech frequency is monitored by counter in time domain. The counter transfers the sinusoidal sound to rectangular wave using comparator and counts the number of rectangular wave in a certain time period, that is frequency, to monitor the howling. Telephone have microphone and speaker, which are fitted in a rigid structure and frequency band of telephone sound is limited, so howling occurs in the limited frequency band. If the counter notices that howling conditions happen, microprocessor decreases quickly the gain of the related frequency band. The result of test of our new hearing aid telephone showed that we can amplifiy the sound as much as 40dB, which is meaningful level to many HIP, and make HIP increase their perception ability from 20% to 60.8% in 1 syllable test and from 28.9% to 78% in 2 syllable test.

헤어리베치(Vice villosa Roth) 품종별 국내 월동성, Biomass 및 무기태 질소 함량비교

이상민,이연,이용환,성좌경,윤홍배,최현석,Lee, Sang-Min,Lee, Youn,Lee, Yong-Hwan,Sung, Jwa-Kyung,Yun, Hong-Bae,Choi, Hyun-Sug 한국유기농업학회 2013 韓國有機農業學會誌 Vol.21 No.1

헤어리베치 8종의 품종별 국내 적응성 검증을 위해 월동률과 biomass, 그리고 토양 중 무기태질소를 조사하였다. 겨울철 월동 후 생존율은 Hungvillosa와 Ostsaat 품종에서 좋았고, Minnie, Oregon common과 TTF1에서 낮았다. 생존율은 biomass에도 영향을 주어서 Hungvillosa와 Ostsaat 품종에서 가장 높았다. 헤어리베치 품종 간 무기성분 농도는 별다른 차이가 관찰되지 않았다. 토양 중 무기태질소 농도는 질소환원능이 좋았던, Hungvillosa와 Ostsaat가 예초 후 10여일 후에 크게 증가시켰다. This study was conducted to evaluate overwintering of hairy vetch (Vicia villosa Roth), biomass, and inorganic N concentration in soil to verify the adaptability of eight cultivars of hairy vetch into country. Winter survival rate was higher for the hairy vetch cultivars, such as Hungvillosa or Ostsaat, than those of Minnie, Oregon common, and TTF1, which affected amount of biomass of each hairy vetch, with higher biomass observed in Hungvillosa or Ostsaat cultivar. There were no significant difference for the mineral nutrients of each hairy vetch cultivar. Inorganic N concentration in soil was increased at 10 days after mowing by application of Hungvillosa and Ostsaat cultivars that had highly produced N content from the raw materials.

대장직장 종양에 대한 내시경 점막하 절제술의 연대순 임상 결과와 학습 곡선

이상민 ( Sang Min Lee ),김은수 ( Eun Soo Kim ),박경식 ( Kyung Sik Park ),조광범 ( Kwang Bum Cho ),김동춘 ( Dong Choon Kim ),강유진 ( Yu Jin Kang ),이유진 ( Yoo Jin Lee ),이정민 ( Jung Min Lee ),최은성 ( Eun Sung Choi ),최재혁 ( Ja 대한소화기학회 2014 대한소화기학회지 Vol.64 No.4

Background/Aims: Endoscopic submucosal dissection (ESD) is an effective procedure for en-bloc curative resection of the colorectal tumor. As it requires high technical skills and experience in therapeutic endoscopy, it is important to understand learning curve of ESD technique. The aim of this study was to retrospectively describe the clinical results of ESD and to evaluate learning curve for the ESD of colorectal tumors. Methods: A total of 90 patients with 90 colorectal neoplasms, who had undergone ESD at a tertiary referral hospital from July 2009 to December 2012, were enrolled. The ESD was performed by a single endoscopist. All ESD cases were divided into three periods: first, cases 1-30; second, cases 31-60; and third, cases 61-90. Results: The en-bloc resection rates in third period (100%) was significantly higher than that of the first (93.3%) and second period (80%) (p=0.025). The perforation rate in third period (0%) also significantly decreased compared with that of the first (13.3%) and second period (20%) (p=0.032). To calibrate the difference of tumor size among periods, proficiency was calculated, as the procedure time per specimen area (min/cm2). The proficiency in third period (4.3) was significantly shorter than that of the first (16.8) and second period (10.2) (p=0.004). Conclusions: The learning curve of colorectal ESD in our study shows that at least 60 cases of ESD have to be conducted to acquire sufficient skill of degree without perforation. (Korean J Gastroenterol 2014;64:198-205)

인산형 연료전지 분리판용 천연흑연-불소수지계 복합재료의 흑연입도에 따른 전기비저항 변화

이상민,백운경,김태진,노재승,Lee, Sang-Min,Beak, Un-Gyeong,Kim, Tae-Jin,Roh, Jae-Seung 한국재료학회 2017 한국재료학회지 Vol.27 No.12

A composite material was prepared for the bipolar plates of phosphoric acid fuel cells(PAFC) by hot pressing a flake type natural graphite powder as a filler material and a fluorine resin as a binder. Average particle sizes of the powders were 610.3, 401.6, 99.5, and $37.7{\mu}m$. The density of the composite increased from 2.25 to $2.72g/cm^3$ as the graphite size increased from 37.7 to $610.3{\mu}m$. The anisotropy ratio of the composite increased from 1.8 to 490.9 as the graphite size increased. The flexural strength of the composite decreased from 15.60 to 8.94MPa as the graphite size increased. The porosity and the resistivity of the composite showed the same tendencies, and decreased as the graphite size increased. The lowest resistivity and porosity of the composite were $1.99{\times}10^{-3}{\Omega}cm$ and 2.02 %, respectively, when the graphite size was $401.6{\mu}m$. The flexural strength of the composite was 10.3MPa when the graphite size was $401.6{\mu}m$. The lowest resistance to electron mobility was well correlated with the composite with lowest porosity. It was possible the flaky large graphite particles survive after the hot pressing process.

주성분 분석 기법을 이용한 심음 인식

이상민,홍승홍,Lee, Sang-Min,Hong, Seung-Hong 대한전자공학회 2001 電子工學會論文誌-SC (System and control) Vol.38 No.5

Recently many researches concerning heart sound analysis are being processed with development of digital signal processing and electronic components. But there are few researches about recognition of heart sound, especially full cardiac cycled heart sound, In this paper, a new recognition methods about. full cardiac cycled heart sound was proposed. For the first, the database was built by principal components analysis on training heart sound set. This database is used to recognize new input of heart sound, Ilear sounds were classified into seven classes such as normal(NO) class, pre-systolic murmurr(PS) class, early systolic murmur(ES) class, late systolic murmurr(LS) class, early diastolic murmur(EI) class, late diastolic murmur(LD) class and continuous murmuru(CM) class. As a result, we could verify that our new method has better efficiencies for the recognition the characteristics of heart sound than any precedent research. The maximum recognition rates of the new method are 71% for NO, 80% for PS and ES, 78% for LS, 87% for ED, 60% for LD and 20% for CM. Although the present results aren't practically sufficient to use our new method in recognizing heart sound, the importance of this paper is for recognition of heart sound within full cardiac cycle. We can get a better result by building a more efficient database. 최근에 디지털 선호처리와 전자부품의 발달로 심음 분식에 관한 많은 연구가 진행되고 있다. 그러나 심음 인식, 특히 심음 한주기 전체에 대한 인식연구는 거의 없다. 본 논문에서 심음 전체 한주기에 대한 새로운 인식 방법을 제안하였다. 먼저 주성분 분석을 이용하여 훈련 셋트로 데이터베이스를 구축한다. 데이터베이스는 새로운 심음입력을 인식하는데 이용된다. 심음은 정상심음, 수축전 심잡음, 수축초기 심잡음, 수축 말기 심잡음, 이완 초기 심잡음, 이완 말기 심잡음, 연속적 심잡음으로 분류된다. 실험결과 새로운 인식 방법은 심음의 특징을 인식하는데 효과적이었다. 최대 인식률은 NO의 경우 71%, PS와 ES의 경우 80%, LS의 경우 78%, ED의 경우 87%, LD의 경우 60%, CM의 경우 20% 이었다. 현재의 결과가 실제적으로 심음을 인식하기에는 충분하지 못하였지만 선음 전체 주기를 대상으로 한 연구라는데 의의가 있으며 더 효과적인 데이터베이스를 구축함으로써 인식률을 개선할 수 있다.

폐 활성슬러지의 화학적 개질을 통한 비소의 생물흡착 특성

이상민,김동욱,Lee, Sang-Min,Kim, Dong-Wook 대한자원환경지질학회 2005 자원환경지질 Vol.38 No.5

비소를 제거하기 위한 경제적이고 친환경적인 생물흡착제 제조를 위해 폐 활성슬러지를 사용하여 생물흡착제로서의 적용성을 검토하였다. 생물흡착제로 사용된 폐 활성슬러지는 비소 흡착능 향상을 위해 각각 9시간과 24시간 메틸화(methylation) 되었고 흡착된 비소는 24시간 메틸화한 활성슬러지가 9시간보다 향상된 결과를 나타내었다. 24시간 메틸화한 활성슬러지의 비비소흡착량(specific As adsorption)은 0.06mmol As(V)/g biomass이고 용액의 pH가 비소에 미치는 영향은 생물흡착제로 사용된 활성슬러지가 메틸화된 후에도 지속되었다. 비소 제거에 대한 pH 영향은 5, 7, 9 세가지 경우에 대해서 조사되었고 이중 pH 5일때 비비소흡착량(specific As adsorption)이 pH 9인 경우보다 3배 큰 비흡착량을 나타내었다. Cheap and environmental sound biosorbent was made for the adsorption of arsenate using an waste activated sludge. The biosorbents were methylated in 9hours and 24 hours respectively for the better adsorption of arsenate. The amount adsorbed of arsenate(V) increased with increasing methylation time. The specific arsenate adsorption was 0.06mmol As(V)/g biomass when the biosorbent was methylated in 24 hours. The methylated biosorbents were also studied with pH 5, 7 and 9. The pH of the solution affect the amount of adsorption of arsenate of the biosorbent even though it was methylated. The specific arsenate adsorption of the biosorbent at pH 5 was best and it was three times greater than the amount of arsenate adsorbed at pH 9.