• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.210-221
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• 1995

The purpose of this study was performed to investigate the mineralization and differentiation of osteobalsts for bone regeneration in vitro and the effect of rate of the composition in periodontal cells on mineralization. For this study, healthy gingival tissues were surgically obtained from the patients during 1st premolar extraction for the purposes of orthodontic treament. Gingival tissue was washed several time with Phosphate buffered saline contained high concentration of antibiotics and antifungal agent, and cultured in Dulbecco's Modified Eagle's Medium(DMEM, Gibco, U.S.A.). Every cell were cultured in state at $37^{\circ}C$, 100% of humidity, 5% of $CO_2$ incubator. Bone marrow stromal cells were isolated from 5-clay-old rat femur with using medium irrigation mathod by syringe. Cell suspension medium were centrifuged at 1500 rpm for 5 min and then cultured in the petri dish. Two kinds of cell were freezed and stocked in the liquid nitrogen tank until experiment. Cell were incubated into the 24 multi-well plate with $5{\times}10^4$cell/well of medium at $37^{\circ}C$, 100% of humidity 5% $CO_2$ incubator for 24 hours. After discarded of the supernatent of medium, O.5ml of medium were reapplied and incubated. And counted the number of cell using the hemocytometer and inverted light microscope. We have measured the number of mineralized nodule with using Alizarin red S. staining in microscope. Furthermore every cell were observed the morphological change between every rate of co-culture of the two kinds of cell. The results were as follows; The rate of proliferation of co-culture cell revealed high rate tendency compared the bone marrow stromal cell only and low growth rate to compared with gingival fibroblast only. The tendency of formation of the mineralized nodule were observed dose-depend pattern of bone marrow stromal cell. It is concluded that the gingival fibroblast may inhibit the formation of mineralized nodule in the culture of the bone marrow stromal cell.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.143-148
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• 1996

Detailed analyses have been presentd for a basic single-electron-logic-cell consisting of two single-electron-transistors (SETs) in series. The interconnection between two SETs has been treated as a coulomb island and the joint probability density function of all three coulomb islands (two from the SETs and one form the interconnection) has been exactly calculated. The average number of electrons in each coulomb island and the steady-state ouptut voltage have been calculated and analyzed.

• Journal of Embryo Transfer
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• v.12 no.3
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• pp.247-251
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• 1997

This research was conducted to observe developmental capacity of the early embryos aggrigated to phytohemagglutinin-M(PHA-M) in the culture of mouse embryos in vitro. The results showed that the development of blastocyst increased to 2-celT >< 2-cell : 68. 9%, 4-cell $\times$4-cell : 92.5% and 8-cell $\times$8-cell : 97.3% in the aggrigated embryos of ICR mouse, and 2-cell $\times$ 2-cell : 90.0%, 4-cell $\times$4-cell : 93.9% and 8-cell $\times$ 8-cell : 100% in the aggrigated embryos of two different strains (ICR $\times$ CBA/J mouse). (Key words : aggrigated embryos, in vitro 2-cell block, phytohemagglutinin-M, blastocyst)

• Journal of Multimedia Information System
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• v.3 no.4
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• pp.119-128
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• 2016

This study aims to suggest a new algorithm for detecting two-wheelers on road that have various shapes according to the viewing angle for vision based intelligent vehicles. This article describes a new approach to two-wheelers detection algorithm riding on people based on modified Histogram of Oriented Gradients (HOG) using correlation coefficient (CC). The CC between two local area variables, in which one is the person riding a bike and other is its background, can represent correlation relation. First, we extract edge vectors using HOG which includes gradient information and differential magnitude as cell based. And then, the value, which is calculated by the CC between the area of each cell and one of two-wheelers, can be extracted as the weighting factor in process for normalizing the modified HOG cell. This paper applied the Adaboost algorithm to make a strong classification from weak classification. In this experiment, we can get the result that the detection rate of the proposed method is higher than that of the traditional method.

• Current Photovoltaic Research
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• v.4 no.1
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• pp.1-7
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• 2016

Among the various types of solar cells, silicon based two terminal tandem solar cell is one of the most popular one. It is designed to split the absorption of incident AM1.5 solar radiation among two of its component cells, thereby widening the wavelength range of external quantum efficiency (EQE) spectra of the device, in comparison to that of a single junction solar cell. In order to improve the EQE spectra further and raise short circuit current density ($J_{sc}$) an optimization of the tradeoff between the top and bottom cell is needed. In an optimized cell structure, the $J_{sc}$ and hence efficiency of the device can further be enhanced with the help of light trapping scheme. This can be achieved by texturing front and back surface as well as a back reflector of the device. In this brief review we highlight the development of light trapping in the silicon based tandem solar cell.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.3
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• pp.217-224
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• 2018

In this study, the optimal design methods of soft-switching cell for high-voltage DC-DC converter (HDC) of fuel cell electric vehicles (FCEVs) is proposed for high efficiency and high power density. The appropriate soft-switching cell for FCEVs is chosen by analyzing the losses of HDC which adopts soft-switching cell. The proposed optimal design methods for the soft-switching cell are divided into two purposes which are improvement of efficiency and power density. Two kinds of design methods enable to improve fuel efficiency and cost, respectively. The proposed design methods are validated with the experimental results based on the specification and hardware used in actual FCEVs.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.58-64
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• 1963

Authors propose a new technique using polyethylene film instead of sodium chloride window as a cell material. Nujol mulls, liquids and aqueous solutions are sandwitched between two pieces of polyethylene film which are held between cardboards. Ordinary lead or stainless steel spacers could be used if exact cell thickness is desired. A more elaborate cell can be assembled by injecting samples between two pieces of polyethylene film which are placed between sodium chloride windows of ordinary demountable liquid cell. The absorption bands due to polyethylene and Nujol are compensated by placing the polyethylene film of suitable thickness in the reference beam. The absorption bands due to solvents such as water can also be compensated by the polyethylene film cell sandwitched solvent of suitable thickness in the reference beam. This method would be a simple new technique. Especially this technique may offer a new helpful way for the investigation of the state of substances in aqueous system. Using this technique, authors have observed the appearance of an absorption bands at 3.2 micron, in the spectrum of phenol in aqueous solution, that is absent in the spectrum of phenol in benzene solution. The same absorption band also has been observed in the spectra of aqueous formaldehyde solution and aqueous polyvinyl alcohol solution, where the absorption bands due to polyethylene and water are compensated. Although it may be regarded that this absorption band is related to the intermolecular interaction between water and the solute having OH group, that is hydrogen bonding. The exact assignment of this absorption band is out of this work.

• BMB Reports
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• v.31 no.2
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• pp.183-188
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• 1998

2-chloroethylethyl sulfide (CEES) is an alkylating agent that readily reacts with a wide variety of biological molecules causing metabolic abnormality. The mechanism of cell death during CEES injury is poorly understood. We have examined the effect of exposure of thymocytes with various concentrations of CEES to determine the pattern of cell death in thymocytes injury induced by CEES. In the present study, we show that two patterns of cell death occurred by either one of two mechanisms: apoptosis and necrosis. Exposure to low level of CEES (100 ${\mu}M$) for 5 h caused an induction of apoptosis on thymocytes, as identified by the following criteria: DNA fragmentation visualized by the characteristic "ladder" pattern was observed upon agarose gel electrophoresis and morphological features were revealed by microscopical observations. In contrast, exposure to high levels of CEES (500 ${\mu}M$) induce necrotic features such as cell lysis. Thus, depending on the concentrations, CEES can result in either apoptotic or necrotic cell damage. Our findings suggest that thymocytes which are not killed directly, but merely injured by low levels of CEES, are able to activate an internally-programmed cell death mechanism, whereas thymocytes receiving severe damages apparently can not.

• The Korean Journal of Cytopathology
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• v.13 no.2
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• pp.88-92
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• 2002

Scattered single cells or variable sized clusters of signet ring cells in the aspirated smears of breast lesions are almost exclusively associated with carcinoma. The signet ring cells are defined as those containing a prominent intracytoplasmic vacuole or amorphous cytoplasm diffusely dispersed with mucin. The primary signet ring cell carcinoma of the breast behaves more aggressively than carcinoma without signet ring cells. Therefore, it is very important to make a correct diagnosis of signet ring cell carcinoma. Fine needle aspiration cytology is useful for diagnosis of breast lesions Including signet ring cell carcinoma. We report two cases, which showed mostly signet ring cells in the aspirated smears of the breast. One case consisted of numerous individual signet ring cells and variable sized cell clusters in rather mucoid background. The tumor cells had abundant amorphous cytoplasm filled with dispersed mucin or occasionally mucin vacuoles(PAS +) and eccentric nuclei. The resected mass revealed mucinous carcinoma. The other showed the cytologic findings of low cellularity, and small loosely cohesive signet ring cell clusters with mild nuclear pleomorphism. It was confirmed as lobular signet ring cell carcinoma in the resected tumor.