• Smart Structures and Systems
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• v.3 no.2
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• pp.173-188
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• 2007

The general solution for two-dimensional magneto-electro-elastic media in terms of four harmonic displacement functions is proposed analytically. The expressions of specific solutions of magneto-electro-elastic plane problems with specific body forces are derived. Finally, based on the general solution in the case of distinct eigenvalues and the specific solution for density functionally gradient media, two kinds of beam problems with body forces depending only on the z or x coordinate are solved by the trial-and-error method.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.1
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• pp.8-13
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• 2019

Objective: Density gradient centrifugation (DGC) is frequently used to isolate high-motility fractions of spermatozoa. We compared the efficacy of four DGC media in terms of the percentage of morphologically normal spermatozoa, DNA fragmentation level, and hyaluronic acid (HA) binding ability. Methods: Thirty men with a total motile spermatozoa count > 80 million participated. Semen samples were divided into four aliquots, which were processed using PureSperm, PureCeption, Sidney, and SpermGrad media, respectively. The DNA fragmentation level was measured using the Halosperm assay kit and HA binding ability was measured using the HBA assay kit. Results: The mean percentage of morphologically normal spermatozoa was significantly enhanced after DGC using all four media (10.3%, 9.9%, 9.8%, and 10.7%, respectively; p< 0.05 for each when compared with 6.9% in raw semen). The DNA fragmentation level was significantly reduced after DGC using PureSperm, PureCeption, and SpermGrad media (6.0%, 6.5%, and 4.9%, respectively; p< 0.05 for each when compared with 11.2% in raw semen), but not after DGC using Sidney media (8.5%, p> 0.05). HA binding ability did not change after DGC using any of the four media. Conclusion: The four media were equally effective for obtaining a sperm fraction with highly motile, morphologically normal sperm. PureSperm, PureCeption, and SpermGrad media were equally effective for acquiring a sperm fraction with less DNA fragmentation.

• Journal of the Optical Society of Korea
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• v.4 no.2
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• pp.86-88
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• 2000

A sequence of functions are examined for the gradient-index AR thin film between two dielectric media and are used as the starting profiles in optimization to improve AR performance. Sinusoidal functions were quite efficient to use as components of the index change in the optimization. It is shown that there exist a number of gradient-index profiles which exhibit excellent AR-performance after control of the gradient-index profiles.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.91-94
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• 1998

본 논문에서는 블록간, 블록 내수, 수평. 수직 방향성, 그리고 시간 영역의 정보를 이용하는 압축 동영상의 블록화 및 링 현상을 제거하는 방식을 제안한다. 위의 정보를 이용하여 새로운 부가 함수가 정의되며, 최적 해를 구하기 위해 gradient와 projection을 결합시킨 hybrid 형태의 기법을 이용한다. 또한, 정규화 계수들 및 projection을 위한 영역의 설정을 부호화단에서는 이용 가능한 정보로부터 추출하게 되므로 계산량을 감소시킬 수 있다. 실험 결과로부터 제안된 방식의 효율성을 확인할 수 있다.

• The Korean Journal of Cytopathology
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• v.15 no.2
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• pp.86-91
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• 2004

Liquid-Based Uterine Cervicovaginal Cytology is known to be a sensitive and effective screening method for cervical neoplasm $MonoPrep^{TM},\;ThinPrep^{TM},\;and\;SurePath^{TM}$ methods have been recently used as Liquid-Based Uterine Cervicovaginal Cytology techniques, and the $SurePath^{TM}$ method has been used in Sung-Yoon Reference Laboratory since 2003. The goal of Liquid-Based Uterine Cervicovaginal Cytology is to separate cervical epithelial cells from non-target cells, red blood cells and neutrophils. This report describes a study which evaluated cellularity, stainablilty, and cellular changes of epithelial cels in samples processed using a manual technique as compared to samples processed using $SurePath^{TM}$ automated method. The samples processed by means of a manual technique contained a cellularity of epithelial cells similar to that of the samples processed using the $SurePath^{TM}$ automated method. In addition, we compared variable density gradient reagents, including dextran, dextrose, and sucrose, to $SurePath^{TM}$ gradient media in order to evaluate cell fractionation and cellularity of epithelial cells. 10% dextran of gradient media shows good fractionation. The samples processed with 10% dextran demonstrated sufficient cellularity of epithelial cells and shows the fewest cellular changes. In conclusion, using a manual technique on these samples is easier to read than those results obtained using the $SurePath^{TM}$ automated method.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.1
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• pp.22-29
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• 2015

Objective: Sperm must be properly prepared in in vitro fertilization (IVF)-embryo transfer (ET) programs in order to control the fertilization rate and ensure that embryos are of high quality and have appropriate developmental abilities. The objective of this study was to determine the most optimal sperm preparation method for IVF. Methods: Patients less than 40 years of age who participated in a fresh IVF-ET cycle from November 2012 to March 2013 were included in this study. Poor responders with less than three mature oocytes were excluded. Ham's F-10 medium or sperm-washing medium (SWM) was used in combination with the density-gradient centrifugation/swim-up (DGC-SUP) or SUP methods for sperm preparation. A total of 429 fresh IVF-ET cycles were grouped according to the media and methods used for sperm preparation and retrospectively analyzed (DGC-SUP/Ham's F-10, n=82; DGC-SUP/SWM, n=43; SUP/Ham's F-10, n=181; SUP/SWM, n=123). Results: There were no significant differences among these four groups with respect to the mean age of the female partners, duration of infertility, number of previous IVF cycles, and retrieved oocytes. We determined that both the DGC-SUP and SUP methods for sperm preparation from whole semen, using either Ham's F-10 or SWM media, result in comparable clinical outcomes, including fertilization and pregnancy rates. Conclusion: We suggest that both media and both methods for sperm preparation can be used for selecting high-quality sperm for assistive reproductive technology programs.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.260-262
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• 2013

본 논문에서는 gradient inverse weighted filtering(GIWF) 보간법 기반의 화면 내 디인터레이싱 알고리듬을 제안한다. 소실된 화소 줄을 보간하기 위해서 먼저 선 처리 과정을 통해 정해진 마스크의 중간 지점의 예측 값을 생성한다. 이 때는 4-tap 필터를 이용을 한다. 다음으로 이웃 픽셀들 사이에서 마스크 내의 기울기 정보를 이용하여 gradient-weighted 필터의 가중치 계수를 계산한다. 그리고 마지막으로 새롭게 제시된 GIWF 보간법을 이용하여 소실된 화소 줄을 보간하게 된다. GIWF를 이용하여 영상의 디테일을 보존하고 잡음을 제거하는 효과를 얻게 되었다. 제안된 방법의 영상 시퀀스에 대한 실험 결과는 기존의 방법들에 비하여 성능의 우수함을 보여준다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.198-199
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• 2018

본 논문은 초해상도 기술을 위한 CNN 구조를 제안한다. 제안하는 Gradient-SR 은 고해상도 영상이 고주파 신호와 저주파 신호로 분리될 수 있다는 점을 바탕으로 고역 통과 필터인 Sobel Operator 를 CNN 기반으로 구성한다. Gradient-SR 로부터 생성된 고주파 신호는 목표 크기로 보간 된 저해상도 입력 영상과 더해짐으로 고해상도 영상을 생성한다. 실험 영상은 VDSR 이 사용 한 291 개의 영상과 B100 영상을 이용한다. 제안하는 방법은 스케일 팩터 2 에 대한 초해상도 영상 생성 실험에서 약 200%의 속도 향상을 보인다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.6
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• pp.693-702
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• 2010

In this paper, FETI(Finite Element Tearing and Interconnecting) method is introduced in order to improve numerical efficiency of Staggered method. The porous media theory, the Staggered method and the FETI method are briefly introduced in this paper. In addition, we account for the MPI(Message Passing Interface) library for parallel analysis, and the proposed combined Staggered method with FETI method. Finally Lagrange multipliers and CG(Conjugate Gradient) algorithm to solve decomposed domain are proposed, and then the proposed method is verified to be numerically efficient by MPI library.

• Smart Media Journal
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• v.2 no.2
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• pp.14-19
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• 2013

Recently, due to the increase of the use of scanned images, the text segmentation techniques, which play critical role to optimize the quality of the scanned images, are required to be updated and advanced. In this study, an algorithm has been developed based on the modification of Gaussian mixture model (GMM) by integrating the calculation of Gaussian detection gradient and the estimation of the number clusters. The experimental results show an efficient method for text segmentation in natural scenes such as storefronts, street signs, scanned journals and newspapers at different size, shape or color of texts in condition of lighting changes and complex background. These indicate that our model algorithm and research approach can address various issues, which are still limitations of other senior algorithms and methods.