• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.542-546
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• 2009

모바일상의 혼합현실 기반의 소프트웨어 기술은 현재 국내외적으로 시작 단계에 있다. 하지만 급속한 모바일 인터넷 인프라의 확산, 모바일 기기의 성능 향상 및 개방형 모바일 OS의 등장으로 인해 모바일 혼합현실과 같은 새로운 융합형 IT기술이 사용자의 요구에 부흥하여, 수요가 급신장 되고 있다. 모바일 혼합현실 기반 기술 중 하나인 마커의 검출과 추적은 혼합현실의 가장 기본이며 매우 중요한 과정이다. 본 논문에서는 낮은 CPU를 이용하는 모바일 환경에 최적화된 실시간 마커 추적 방법에 대하여 제안한다. 낮은 CPU의 처리속도를 보완하기 위하여 처리영역을 축소하여 가변 탐색영역내의 공간에서 처리를 수행하고, 좌표변환정보를 이용하여 추적을 수행하는 캘리브레이션 과정을 대신하여 캠 시프트 알고리즘을 이용하여 효과적인 추적 방법을 제안한다.

• 대한조선학회논문집
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• 제53권1호
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• pp.1-9
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• 2016

It is important to research and understand the physical phenomenon around a semi-submersible offshore structure on waves and currents because the wave run-up and load occurs owing to the waves and currents. In this study, the numerical simulations are performed about flow around a fixed semi-submersible offshore structure. The Modified Marker-density method is adopted in the present computation procedure, this method is one of the various methods to define the free-surface. The present computation results are compared with existing experimental and numerical simulation(VOF method) results. And, the computation results are relatively coincident with the existing results of model test and numerical simulation by VOF method.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 Proceeding of CIN-KIN Joint Symposium 2000 on M.E.T. Under STCW 78/95 and SINO-KOREA MARITIME CONTACT IN MID-CENTURIES
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• pp.107-114
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• 2000

Marine analysis was made to investigate the hydrodynamic effects of a Wing in Ground (WIG) by means of finite difference techniques. The air flow field around WIG is analyzed by the Marker & Cell (MAC) based method, and the interaction between WIG and the free surface are studied by showing pressure distributions above the free surface. In the latter part, computations are extended to make clear the flow characteristics of a high speed catamaran in the rang of Froude numbers 0.2 to 1.0 with a separation to length ratios of 0.2, 0.3 and 0.5. The Navier-Stokes solver is invoked in which the nonlinear free-surface boundary condition is applied. For the validation, computational results are compared with the experiments.

• 한국가축번식학회지
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• 제20권3호
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• pp.333-341
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• 1996

One of the biggest problems involved in transgenic animal production is lack of appropriate market genes. To overcome this problem, we tested whether the genes of SEAP (secreted alkaline phosphatase) and GFP (green fluorescence protein) on our retrovirus vectors can be applicable to the transgenic animal production. The main advantage of these marker genes over other generally mainpulation can be selected without sacrificing viability. The results obtained in this study are summarized as follows: 1. Removal of zona pellucida from the mouse zygotes did not affect embryo developments to blastocysts. 2. Co-culture of zona-free embryos with virus-producing cells for 6 hours also did not affect embryo developments to blastocysts. 3. Among 58 blastocysts developed from the zona-free zygotes co-cultured with the virus-producing cells, SEAP expression was observed from the 6 blastocysts. 4. Expression of the GFP gene was detected from the virus- producing cells but no embryo expressing the gene was counted among 50 blastocysts developed from the zona-free zygotes co-cultured with the virus-producing cells.

• 한국해양공학회지
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• 제17권6호
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• pp.7-15
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• 2003

A Digital Wave Tank simulation technique, based on a finite-difference method and a modified marker-and-cell (MAC) algorithm, is applied in order to investigate the characteristics of nonlinear Tsunami propagations and their interactions with a 2D sloping beach, Ohkushiri Island, and to predict maximum wove run-up around the island. The Navier-Stokes (NS) and continuity equation are governed in the computational domain, and the boundary values are updated at each time step, by a finite-difference time-marching scheme in the frame of the rectangular coordinate system. The fully nonlinear, kinematic, free-surface condition is satisfied by the modified marker-density function technique. The near shore Tsunami is assumed to be a solitary wave, and is generated from the numerical wave-maker in the developed Digital Wave Tank. The simulation results are compared with the experiments and other numerical methods, based on the shallow-water wave theory.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.231-239
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• 2003

A Digital Wave Tank simulation technique based on a finite-difference method and a modified marker-and-cell (MAC) algorithm is applied to investigate the characteristics of nonlinear Tsunami propagations and their interactions with a 2D sloping beach and Ohkushiri island, and to predict maximum wave run-up around the island. The Navier-Stokes (NS) and continuity equation are governed in the computational domain and the boundary values updated at each time step by a finite-difference time-marching scheme in the frame of rectangular coordinate system. The fully nonlinear kinematic free-surface condition is satisfied by the modified marker-density function technique. The Nearshore Tsunami is assumed to be a solitary wave and generated from the numerical wavemaker in the developed Digital Wave Tank. The simulation results are compared with the experiments and other numerical methods based on the shallow-water wave theory.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.353-361
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• 2012

Human embryonic stem (ES) cells are a potential source of cells for developmental studies and for a variety of applications in transplantation therapies and drug discovery. However, human ES cells are difficult to culture and maintain at a large scale, which is one of the most serious obstacles in human ES cell research. Culture of human ES cells on MEF cells after disassociation with accutase has previously been demonstrated by other research groups. Here, we confirmed that human ES cells (H9) can maintain stem cell properties when the cells are passaged as single cells under a feeder-free culture condition. Accutase-dissociated human ES cells showed normal karyotype, stem cell marker expression, and morphology. We prepared frozen stocks during the culture period, thawed two of the human ES cell stocks, and analyzed the cells after culture with the same method. Although the cells revealed normal expression of stem cell marker genes, they had abnormal karyotypes. Therefore, we suggest that accutase-dissociated single cells can be usefully expanded in a feeder-free condition but chromosomal modification should be considered in the culture after freeze-thawing.

• 한국발생생물학회지:발생과생식
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• 제19권3호
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• pp.119-126
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• 2015

The suitable feeder cell layer is important for culture of embryonic stem (ES) cells. In this study, we investigated the effect of two kinds of the feeder cell, MEF cells and STO cells, layer to mouse ES (mES) cell culture for maintenance of stemness. We compare the colony formations, alkaline phosphatase (AP) activities, expression of pluripotency marker genes and proteins of D3 cell colonies cultured on MEF feeder cell layer (D3/MEF) or STO cell layers (D3/STO) compared to feeder free condition (D3/-) as a control group. Although there were no differences to colony formations and AP activities, interestingly, the transcripts level of pluripotency marker genes, Pou5f1 and Nanog were highly expressed in D3/MEF (79 and 93) than D3/STO (61and 77) or D3/- (65 and 81). Also, pluripotency marker proteins, NANOG and SOX-2, were more synthesized in D3/MEF ($72.8{\pm}7.69$ and $81.2{\pm}3.56$) than D3/STO ($32.0{\pm}4.30$ and $56.0{\pm}4.90$) or D3/- ($55.0{\pm}4.64$ and $62.0{\pm}6.20$). These results suggest that MEF feeder cell layer is more suitable to mES cell culture.

• KSBB Journal
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• 제13권3호
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• pp.295-302
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• 1998

Human Erythropoietin (EPO) gene is cloned in quail fibrosarcoma cell, QT35. Because molecular weight of EPO is similar to that of serum albumin, cell culture with serum containing medium makes purification of EPO very difficult. Using fractional factorial study, we have developed serum free medium for the recombinant QT35 cell lines, QT N4D4 and QT SY-IMP, which have cloned EPO with glutamine synthetase (GS) gene amplification system and with puromycin selective marker, respectively. Among the seven frequently used medium components, fibronectin, BSA, and EGF were the most important for EPO production. However, sufficient fibronectin supplement to the medium did not make any good attachment of QT35 to culture plate over 3 days. Therefore, to maximize EPO production, we attempted a medium-shift at confluence from serum containing medium to serum free medium(QT SFM6). Using the medium-shift protocol with QT SFM6, nearly the same productivity of EPO was achieved comparing with that without medium-shift. This result was true in both QT35 cell lines in three types of culture, i.e. T flask, microcarrier and roller bottle cultures.

• Biomolecules & Therapeutics
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• 제13권3호
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• pp.150-155
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• 2005

The ethanolic extract of chestnut (Castanea crenata S. et Z., Fagaceae) inner shell (CISE) and one of its components, ellagic acid (EA), were evaluated for their protective effects against 1, 1-diphenyl-2-picryl hydrazine (DPPH) free radical generation and hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line. CISE and EA were shown to possess the free radical scavenging effect against DPPH radical generation, significantly. They were also found to strongly inhibit hydrogen peroxide-induced DNA damage from Chinese hamster lung (CHL) cell, assessed by single cell gel electrophoresis assay and 8-hydroxy -2'-deoxy guanosine (8-OH-2'dG) assay. Furthermore, topical application of CISE [$12.5\%$(w/w) cream] and ellagic acid [$1.0\%$(w/w) cream] for 14 days potently inhibited malondialdehyde (MDA) formation of mouse dorsal skin (a marker of lipid peroxidation) induced by ultraviolet B exposure. Therefore, CISE and its component, ellagic acid, may be the useful natural antioxidants by scavenging free radicals, inhibition of lipid peroxidation and protecting oxidative DNA damage when topically applied.