• Clinical and Experimental Reproductive Medicine
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• 제27권4호
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• pp.367-372
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• 2000

Objective: This study was performed to evaluate whether vitrification method could be used for the cryopreservation of human blastocysts derived from IVF program. Methods: Surplus embryos were obtained from consented IVF patients. Controlled ovarian hyperstimulation was done with midluteal GnRH agonist, gonadotropin and hCG. After oocyte retrieval and insemination, fresh embryo transfer was done at $4{\sim}8$ cell stage. The surplus embryos after ET were cultured in blastocyst medium up to 6 days after oocyte retrieval. Obtained blastocysts were cryopreserved with our vitrification method. Blastocysts were exposed to 1.5 Methylene glycol (EG) in phosphate buffered saline (PBS) for 2.5 minutes, followed by 5.5 M EG plus 1 M sucrose for 20 seconds. Then 1 to 3 blastocysts were mounted on electron microscope (EM) grid and the grid was plunged into liquid nitrogen for storage. For thawing, blastocyst-containing EM grids were sequentially transferred in 1.0 M, 0.5 M, 0.25 M, 0.125 M and 0 M sucrose solution at the intervals of2.5 minutes. And blastocysts were cultured for about 6 hours and only re-expanded blastocysts were transferred to uterus of the patients on 4 to 5 days after ovulation in natural cycle or on 18 to 19 day of artificial cycle. Results: From Oct. 1998 to Jul. 1999, 34 patients were agreed to participate in this study. The mean age and duration of infertility of the patients were 31.6 years and 4.1 years, respectively. Among 34 cycles. replacements could be done in 20 cycles (58.8%). A total 93 blastocysts were thawed and 48 (51.6%) of them survived. Thirty-eight blastocysts, mean 1.9 embryos per patient, were transferred, resulting in 5 clinical pregnancies which consisted of 1 triplet, 2 sets of twins and 2 singleton pregnancies. The pregnancy rate per transfer was 25% and implantation rate was 23.6%. Five patients delivered 7 healthy babies including 2 sets of twins at term. Conclusion: Successful pregnancies and deliveries were established after transfer of vitrified human blastocysts. Vitrification using ethylene glycol as cryoprotectant and electron microscope grid is a rapid and simple method that can be effectively applied for the cryopreservation of human blastocysts.

• Journal of electromagnetic engineering and science
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• 제19권1호
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• pp.6-12
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• 2019

An IE-FFT algorithm is implemented and applied to the electromagnetic (EM) solution of perfect electric conducting (PEC) scattering problems. The solution of the method of moments (MoM), based on the magnetic field integral equation (MFIE), is obtained for PEC objects with closed surfaces. The IE-FFT algorithm uses a uniform Cartesian grid to apply a global fast Fourier transform (FFT), which leads to significantly reduce memory requirement and speed up CPU with an iterative solver. The IE-FFT algorithm utilizes two discretizations, one for the unknown induced surface current on the planar triangular patches of 3D arbitrary geometries and the other on a uniform Cartesian grid for interpolating the free-space Green's function. The uniform interpolation of the Green's functions allows for a global FFT for far-field interaction terms, and the near-field interaction terms should be adequately corrected. A 3D block-Toeplitz structure for the Lagrangian interpolation of the Green's function is proposed. The MFIE formulation with the IE-FFT algorithm, without the help of a preconditioner, is converged in certain iterations with a generalized minimal residual (GMRES) method. The complexity of the IE-FFT is found to be approximately $O(N^{1.5})$and $O(N^{1.5}logN)$ for memory requirements and CPU time, respectively.

• 지구물리와물리탐사
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• 제18권3호
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• pp.143-153
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• 2015

탄화수소 생산에서 화학공법은 폴리머 용액을 저류층에 주입함으로써 탄화수소의 생산량을 증대시키는 방법이다. 화학공법의 유용성을 파악하기 위해서는 저류층 내 폴리머 용액의 거동 양상을 모니터링하는 것이 매우 중요하다. 저류층 내 폴리머 용액과 유체 변화에 대한 모니터링의 가능성을 확인하기 위해, 저류층을 구성하고 있는 암석 및 유체의 종류, 포화도 등의 매개변수에 따른 탄성파 및 전기비저항 암석물리모델을 구성하고, 폴리머 주입에 따른 탄성파 및 EM 토모그래피의 반응을 계산하였다. 특히 전기비저항 암석물리모델 구성에서는 순수사암, 셰일질 사암, 사암셰일박리층 3가지의 서로 다른 저류층 암석을 고려하였다. 폴리머 용액의 농도는 가장 일반적으로 이용되는 2 wt%로 하고 담수를 이용한 경우와 염수를 이용한 경우로 나누어 분석하였다. 더 나아가, 화학공법에 대한 중성자검층 민감도 분석을 수행하였다. 이 논문에서 다루는 기법들은 탄화수소 저류층뿐만 아니라 지열 저류층 등의 모니터링에 있어서도 중요하게 적용될 것이다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.571-574
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• 2016

최근 에너지 효율을 최적화하는 차세대 지능형 전력망인 스마트 그리드 시스템(Smart Grid System)이 국내외에 널리 보급되고 있다. 그로 인해 그리드 시스템의 효율적인 운영을 위해 적용되는 EMS(Energy Management System) 기술의 중요성이 커지고 있다. EMS는 에너지 사용량 예측의 높은 정확성이 요구되며, 예측이 정확하게 수행될수록 에너지의 활용성이 높아진다. 본 논문은 전력 사용량 예측의 정확성 향상을 위한 새로운 기법을 제안한다. 구체적으로, 먼저 사용량에 영향을 미치는 환경적인 요인들을 분석한다. 분석된 요인들을 적용하여 유사한 환경을 가지는 전력 사용량 데이터의 사전 군집화를 수행한다. 그리고 예측 일에 관련된 환경 정보와 가장 유사한 군집의 전력 사용량 데이터를 기반으로 전력 사용량을 예측한다. 제안하는 기법의 성능을 평가하기 위해, 다양한 실험을 통하여 일간 전력 사용량을 예측하고 그 정확성을 측정하였다. 결과적으로, 기존의 기법들과 비교했을 때, 최대 52.88% 향상된 전력 사용량 예측 정확성을 보였다.

• Clinical and Experimental Reproductive Medicine
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• 제29권3호
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• pp.201-207
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• 2002

Objective: To observe the capability of fertilization and embryo development including blastocyst formation of the oocytes in simple media after thawing of the cryopreserved cumulus-free mouse oocytes by vitrification method. Methods: Oocytes were collected from 5 to 6 weeks old ICR female mice, and were denuded from the cumulus cells by 0.1% hyaluronidase. Recovered mature oocytes in study group were cryopreserved by vitrification method using EM grid for $5{\sim}7$ days. In brief, oocytes were exposed in dPBS containing 1.5 M EG and 5.5 M EG+1 M sucrose for 2.5 minutes and 20 seconds each, and then executed vitrification by plunging in LN2 after loading on EM grid. Thawing treated by exposure of 1, 0.5, 0.25 and 0.125 M sucrose solution for 2.5 minutes each in order and used for experiments. Spermatozoa aspirated form the epididymis of 12 weeks old ICR male mice were used for insemination after capacitation. T6 media containing 0.4% BSA were used for fertilization and development. Results: Survival and fertilization rates after thawing were 76.9% and 79.6% respectively. Fertilization rate was lower (p<0.005) than that of control group (92.9%). There was no difference in embryo developmental rates from 2-cell to morula, however, the blastocyst formation rate and mean cell numbers of blastocysts in study group (63.3%, $58.9{\pm}9.2$) were lower compared with those of control group (76.1%, $63.5{\pm}8.9$). Conclusion: Vitrification is an effective method for mouse mature oocyte cryopreservation with high survival and fertilization rate after thawing. And in simple media, fertilization rates and embryo development of frozen-thawed mouse oocytes are satisfactory.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.78-78
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• 2002

The role of heat shock proteins in shielding organism from environmental stress is illustrated by the large-scale synthesis of these protein by the organism studied to date. However, recent evidence also suggests an important role for heat shock protein in fertilization and early development of mammalian embryos. Effects of elevated in vitro temperature on in vitro produced bovine embryos were analysed in order to determine its impact on the expression of heat shock protein 70 (HSP70) by control and frozen-thawed after in vitro fertilization (IVF) or nuclear transfer (NT). The objective of this study was to assess the developmental potential in vitro produced embryos with using of the various containers and examined expression and localization of heat shock protein 70 after it's frozen -thawed. For the vitrification, in vitro produced embryos at 2 cell, 8 cell and blastocysts stage after IVF and NT were exposed the ethylene glycol 5.5 M freezing solution (EG 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min, and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid, cryo-loop. However, survival rates by straw were relatively lower than other containers. Only, nuclear transferred embryos survived by using cryo-loop. After IVF or NT, in vitro matured bovine embryos 2 cell, 8 cell and blastocysts subjected to control and thawed conditions were analysed by semiquantitive reverse transcription polymerase chain reaction methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNA were higher thawed embryos than control embryos. Immunocytochemistry used to localization the hsp70 protein in embryos. Two, 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some embryos exposed frozen-thawed. However, under control condition, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform in distribution.

• 한국전자파학회논문지
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• 제23권3호
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• pp.384-391
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• 2012

본 논문은 철근 콘크리트에 대한 전자기적 모델링을 하고, 전파에 대한 차폐 효과를 분석하였다. 철근 콘크리트는 대부분의 건축물에 쓰이고 있으며, 내부에 격자 구조의 철근을 설치하기 때문에 특정 주파수 대역에서 전파의 차폐 효과가 있다. 철근 콘크리트의 해석은 3D EM(3-dimensional electromagnetic) 시뮬레이션 툴을 이용하여 철근과 콘크리트를 각각 해석한 뒤 그 영향을 고려하여 전체 철근 콘크리트의 해석을 하였다. 콘크리트의 경우 주파수가 높아짐에 따라 손실 특성 역시 높아져 차폐 효과가 커진다. 단층 철근의 경우 철근의 두께가 두꺼워질수록 차폐 효과가 커지며 주파수가 낮을수록 철근에 의한 차폐 효과가 커지는 것을 분석하였다. 또한, 철근과 철근 사이의 간격이 넓어질수록 차폐 효과가 낮아진다. 철근 구조를 2층으로 확장한 경우에 대해서도 철근과 철근 층 사이의 거리에 따른 차폐 효과에 대한 분석을 하였다. 철근 콘크리트 단층 철근을 사용한 경우, 철근두께 가 10, 20, 30 mm일 때 500 MHz에서 각각 철근 콘크리트 두께 10 cm당 -1.89, -2.73, -4.76 dB/10 cm의 투과 특성 값을 가지며, 두 층 철근을 이용한 경우에도 철근 두께에 대하여 -2.46, -6.16, -9.55 dB/10 cm의 투과 특성을 나타낸다.

• Clinical and Experimental Reproductive Medicine
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• 제28권3호
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• pp.191-198
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• 2001

Objective : This study was conducted to examine the effect of vitrification on the survival and in vitro development of mice 1-cell zygotes. Method: Effects of exposure to vitrification solution and vitrification, with different concentrations of the cryoprotectant solution, were examined. The 1-cell zygotes were also subjected to a slow freezing-thawing method to compare with vitrification method. Solution composed of ethylene glycol (6.0 M, 5.0 M, 4.0 M) and sucrose (1.0 M) were used as cryopropectant. The experiments employed the method loading the embryos on electron microscope grids. Results: I. The effects of exposure in vitrification solution. 1-cell zygotes were non-toxic at all concentrations of the vitrification solution showing the survival rate between 88.1% and 97.5%. Development into 2-cell was more successful in the higher concentrations of the vitrification solution. Therefore, higher concentrations of the vitirification solution do not seem to cause any problems in vitrification procedure. II. The effects of vitrification method. 1-cell zygotes showed the survival rate between 78.8% and 92.4%. The lowest and the highest survival rate was observed in the 6.0 M and 4.0 M vitrification solution, respectively. 2-cell development rates varied from 77.6% to 91.3%. Blastocyst development rate was shown highest in 5.0 M and the lowest in 4.0 M solution. Therefore, the highest 2-cell and blastocyst development rate was observed in 5.0 M solution. III. Comparison of vitrification and slow freezing-thawing method on 1-cell zygotes. This experiment showed that 1-cell zygotes had the highest survival and development rates in 5.0 M vitrification solution. Vitrified group of 1-cell zygotes, in the 5.0 M vitrification solution, were compared with the group processed in slow freezing-thawing method. The development rate into 2-cell and blastocyst as well as the survival rate were higher in the vitrified group than in the slowly freezed group. Conclusion: 1. The results demonstrate that the best cryoprotectant is a 5.0 M vitrification solution for 1-cell zygotes. 2. Vitrification method significantly increases the survival rate of the 1-cell zygote and its development into 2-cell and blastocyst. Equilibration and exposure time during the vitrification was remarkerbly short in this experiment. Total time, from the exposure to vitirification solution to storage in the liquid nitrogen, was taken only 90 seconds. In contrast, the slow freezing-thawing method have taken more than four hours. Taken together, we presume that the overall time used for the procedure contributes to the results as an important parameter. 3. The loading of 1-cell zygotes on the EM grid is technically more simple and takes less time than the straw or cryo vial method.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권11호
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• pp.936-946
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• 2009

그래프 컷(graph cuts) 방법은 주어진 사전정보와 각 픽셀간의 유사도를 나타내는 데이터 항(data term)과 이웃하는 픽셀간의 유사도를 나타내는 스무드 항(smoothness term)으로 구성된 에너지 함수를 전역적으로 최소화하는 방법으로, 최근 영상 분할에 많이 이용되고 있다. 기존 그래프 컷 기반의 영상 분할 방법에서 데이터 항을 설정하기 위해 GMM(Gaussian mixture model)을 주로 이용하였으며, 평균과 공분산을 각 클래스를 위한 사전정보로 이용하였다. 이 때문에 클래스의 모양이 초구(hyper-sphere) 또는 초타원(hyper-ellipsoid)일 때만 좋은 성능을 보이는 단점이 있다. 다양한 클래스의 모양에서 좋은 성능을 보이기 위해, 본 논문에서는 mean shift 분석 방법을 이용한 그래프 컷 기반의 자동 영상분할 방법을 제안한다. 데이터 항을 설정하기 위해 $L^*u^*{\upsilon}^*$ 색상공간에서 임의로 선택된 초기 mean으로부터 밀도가 높은 지역인 모드(mode)로 이동하는 mean의 집합들을 사전정보로 이용한다. Mean shift 분석 방법은 군집화에서 좋은 성능을 보이지만, 오랜 수행시간이 소요되는 단점이 있다. 이를 해결하기 위해 특징공간을 3차원 격자로 변형하였으며, mean의 이동은 격자에서 모든 픽셀이 아닌 3차원 윈도우내의 1차원 모멘트(moment)를 이용한다. 실험에서 GMM을 이용한 그래프 컷 기반의 영상분할 방법과 최근 많이 이용되고 있는 mean shift와 normalized cut기반의 영상분할 방법을 제안된 방법과 비교하였으며, Berkeley dataset을 기반으로 앞의 세 가지 방법보다 좋은 성능을 보였다.

• 전자공학회논문지
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• 제52권1호
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• pp.155-161
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• 2015

스마트 그리드 확산사업으로 에너지 저장시스템의 보급이 활발히 이루어지고 있다. 대규모 EES(Electric Energy Storage system)의 경우 수용가에 설치된 BEMS(Building Energy Management System) 또는 BAS(Building Automation System)등과 연동하여 효율적인 제어가 가능하나 일반 주택에 설치되는 EES는 운전 및 제어를 위한 전문 인력이 없어 이를 원격에서 통합관리할 수 있는 시스템이 필요하다. 또한, 태양광 발전과 EES가 동시에 설치된 경우 태양광 발전이나 전력부하에 따라 효율적인 제어를 할 수 있는 소규모의 EMS(Energy Management System)가 필요하게 된다. 본 논문에서는 주택에 설치된 태양광 발전과 EES를 효율적으로 제어하기 위한 EMS를 구현하고 그 유용성을 실험을 통해 확인하였다.