• ETRI Journal
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• v.36 no.4
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• pp.554-563
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• 2014

The burgeoning growth of real-time applications, such as interactive video and VoIP, places a heavy demand for a high data rate and guarantee of QoS from a network. This is being addressed by fourth generation networks such as Long-Term Evolution (LTE). But, the mobility of user equipment that needs to be handed over to a new evolved node base-station (eNB) while maintaining connectivity with high data rates poses a significant challenge that needs to be addressed. Handover (HO) normally takes place at cell borders, which normally suffers high interference. This inter-cell interference (ICI) can affect HO procedures, as well as reduce throughput. In this paper, soft frequency reuse (SFR) and multiple preparations (MP), so-called SFRAMP, are proposed to provide a seamless and fast handover with high throughput by keeping the ICI low. Simulation results using LTE-Sim show that the outage probability and delay are reduced by 24.4% and 11.9%, respectively, over the hard handover method - quite a significant result.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.1
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• pp.48-54
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• 2022

Parthenogenesis is maternally uniparental reproduction through the embryonic development of oocytes without fertilization. Artificial activation of mature oocytes could generate homozygous haploid embryos with the extrusion of the second polar body. However, the haploid embryos showed low embryo development in preimplantation embryos. In this study, we investigated whether the electronic fusion of the haploid embryos could enhance embryo development and ESC establishment in mice. Haploid embryos showed the developmental delay from 4-cell to the blastocyst stage. The haploid blastomeres of the 2-cell stage were fused electronically, resulting in that the fused embryos showed a significantly higher rate of blastocysts compared to non-fused haploid embryos (55% vs. 37%). Further, the embryonic stem cells (ESCs) derived from the fused embryos were confirmed to be diploid. The rate of ESC establishment in fused embryos was significantly higher compared to non-fused ones. Based on the results, we concluded that the electronic fusion of haploid embryos could be efficient to generate homozygous ESCs.

• Journal of information and communication convergence engineering
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• v.20 no.2
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• pp.137-142
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• 2022

Monolithic three-dimensional (M3D) logics such as M3D-NAND, M3D-NOR, M3D-buffer, M3D 2×1 multiplexer, and M3D D flip-flop, consisting of modularized M3D inverters (M3D-INVs), have been proposed. In the previous M3D logic, each M3D logic had to be designed separately for a standard cell library. The proposed M3D logic is designed by placing modularized M3D-INVs and connecting interconnects such as metal lines or monolithic inter-tier-vias between M3D-INVs. The electrical characteristics of the previous and proposed M3D logics were simulated using the technology computer-aided design and Simulation Program with Integrated Circuit Emphasis with the extracted parameters of the previously developed LETI-UTSOI MOSFET model for n- and p-type MOSFETs and the extracted external capacitances. The area, propagation delay, falling/rising times, and dynamic power consumption of the proposed M3D logic are lower than those of previous versions. Despite the larger space and lower performance of the proposed M3D logic in comparison to the previous versions, it can be easily designed with a single modularized M3D-INV and without having to design all layouts of the logic gates separately.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5645-5650
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• 2013

Src homology 2 domain containing (SHC) is a proto-oncogene which mediates cell proliferation and carcinogenesis in human carcinomas. Here, the SHC SH2-domain binding protein 1 (SHCBP1) was first established to be up-regulated in human hepatocellular carcinoma (HCC) tissues by array-base comparative genome hybridization (aCGH). Meanwhile, we examine and verify it by quantitative real-time PCR and western blot. Our current data show that SHCBP1 was up-regulated in HCC tissues. Overexpression of SHCBP1 could significantly promote HCC cell proliferation, survival and colony formation in HCC cell lines. Furthermore, knockdown of SHCBP1 induced cell cycle delay and suppressed cell proliferation. Furthermore, SHCBP1 could regulate the expression of activate extracellular signal-regulated kinase 1/2 (ERK1/2) and cyclin D1. Together, our findings indicate that SHCBP1 may contribute to human hepatocellular carcinoma by promoting cell proliferation and may serve as a molecular target of cancer therapy.

• Preventive Nutrition and Food Science
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• v.16 no.3
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• pp.217-223
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• 2011

Ischemic stroke constitutes about 80% of all stroke incidences. It is characterized by brain cell death in a region where cerebral arteries supplying blood are occluded. Under these ischemic conditions, apoptosis is responsible for the cell death, at least in part. Goat's-beard (Aruncus dioicus var. kamtschaticus) is a perennial plant that grows naturally in the alpine regions of Korea. In the present study, we first determined whether water extract of goat's-beard (HY1646) and some of its fractions prepared by partitioning with organic solvents could improve the viability of human hepatocellular carcinoma cells (HepG2) cultured under hypoxic condition by blocking apoptotic pathways. Based on the in vitro findings, we subsequently investigated whether HY1646 and the ethyl acetate fraction (EA) selected from cell culture-based screening could attenuate brain injury in a rat middle cerebral artery occlusion (MCAO) model of ischemia (2 hr), followed by 22 hours of reperfusion. The cell number was sustained close to that initially plated in the presence of HY1646 even after 24 hr of cell culture under hypoxic condition (3% $O_2$), at which time the cell number reached almost zero in the absence of HY1646. This improvement in cell viability was attributed to the delay in apoptosis, identified by the formation of DNA ladder in gel electrophoresis. Of fractions soluble in hexane, ethyl acetate (EA) and butanol, EA was chosen for the animal experiments because EA demonstrated the best cell viability at the lowest concentration (10 ${\mu}g$/mL). HY1646 (200 mg/kg) and EA (10 and 20 mg/kg) significantly reduced infarct size, an index of brain injury, by 16.6, 40.0 and 61.0%, respectively, as assessed by 2,3,5-triphenyl tetrazolium chloride staining. The findings suggest that prophylactic intake of goat's beard might be beneficial for preventing ischemic stroke.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.351-354
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• 1998

In this paper, we measured inter-floor loss in multifloored building to surround buildings at 910MHz. Effect of interfloor diffraction to propagate through out-surface were smaller than effect of reflection of surrounding buildings. If multifloored building were offered W-PBX service, we will have to design optimization of indoor cell to overcome time delay difference.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.119-122
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• 1998

Wireless ATM(WATM) intends to provide a broad range of mobile multimedia services through wireless access by mobility extensions from the fixed ATM-based network. Recently, there have been active researches about new handover techniques to support terminal mobility in WATM. In this paper we classify path reestablishment schemes into full reestablishment, path rerouting with a static COS, path rerouting with a dynamic COS, and path extension. For a backward lossy handover procedure, we analyze and compare the performances of path reestablishment schemes in terms of delay, service disruption time and cell loss.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.109-112
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• 1996

In this paper, we composed utility interactive photovoltaic generation system of current source inverter, and controlled that low harmonic and high power factor are hold by supposing control and compensation method which is concerned with synchronous signal distortion and modulation delay. And we put parallel resonant circuit into dc link, so, magnitude of direct reactance was reduce by restraining direct current pulsation which had accumulation of pulsating power in alternating electrolytic condenser. Also we controlled that modulation factor is operated around maximum output of solar cell.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.851-854
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• 1998

본 연구는 ring oscillator 및 이의 delay까지도 계수화 함으롯 고정밀 pulse modulation 을 시키기 위한 것이다. 특히 ring oscillator는 온ㄷ, 전압 및 공정에 따라 주파수 변화폭이 심하므로 이에대한 보정 방법과 높은 발진으로 인해 실리콘(반도체) 제작시의 열문제를 최소화 하는 방안에 대해서도 언급하였다. 본 논문은 삼성반도체 0.6um CMOS standar cell을 사용하여 구현 했으며, 레이져 프린터의 해상도 향상을 위해 gray image와 text에 대한 적용 예로서 화상의 미세수평이도오가 화소의 크기를 제어하는 예를 보였다. 또한 향후에는 칼라 프린터에 있어서 인쇄화상의 품질 향상을 위한 정밀 보정에도 응용할수 있음을 보였다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.587-588
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• 2008

Digital PLL을 위한 높은 해상도를 갖는 TDC(Time to Digital Converter)를 $0.18{\mu}m$ CMOS 공정으로 설계하였다. 2단 구조를 갖는 TDC를 제안하였고 이를 Cadence Spectre를 이용하여 검증하였다. TDC는 Difference pulse generator, coarse 변환기와 fine 변환기로 구성된다. 그리고, 2단 변환기와 Thermometer decoder를 이용하여 delay cell의 수를 적게 유지하면서도 높은 해상도를 얻을 수 있었다.