• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.5
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• pp.353-358
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• 2018

We herein analyze the service traffic characteristics and spectrum of the 5G mobile communication and suggest the effective 5G network deployment method for 5G mobile communication services. The data rates of the 5G mobile communication are from several kbps (voice and IoT) up to 1 Gbps (hologram, among others). The 5G mobile communication services show the diverse cell coverage environments owing to the use of diverse service data rates and multiple spectrum bands. To effectively support the 5G mobile communication services, the network deployment requires the optimization of the service coverages for new service environments and multiple spectrum bands. Considering the 5G spectrum bandwidth debated at present, if the 5G services of 100 Mbps can be supported in the 200 m cell edge using the 3.5 GHz spectrum bands, the 5G services of the 1 Gbps hologram and 500-Mbps 4k UHD can be supported in the cell edges of 50 m and 100 m using the 28 GHz spectrum bands. Therefore, the 5G services can be supported effectively by the 5G network deployment using spectrum portfolio configurations to match the diverse 5G services and multiple bands.

• Microbiology and Biotechnology Letters
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• v.21 no.2
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• pp.176-180
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• 1993

Survival and heat resistance of Listeria monocytogenes Scott A in various nutritional environments and cell type on stainless steel were determined. Viable cell of L. monocytogenes Scott A was most rapidly decreased in phosphate buffer among various media such as NSM (30 g TSB/1 l D.W.), LNM (2 g TSB/1 l D.W.) and phosphate buffer (pH=7) during incubation at 21 and 35C but survived for 15 days at 21C. Vegetative and starved L. monocytogenes Scott A were survived after heat treatment for 5 min at 65C while not detected at 72C.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.162-165
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• 2017

In an effort to compensate the rising of the data throughput demand nowadays, there have been many research works to optimize the radio resource and increase the capacity of the network. At the present, small cell network, mmWave band and beamforming technology are leading the trend and becoming the core solutions of the fifth generation (5G) cellular networks. Since the propagation characteristics of radio wave in the mmWave band is quite different from the conventional bands, the communication systems which work in these bands have to be redesigned. In this paper, a 3D simulation model is discussed for cellular network at 60 GHz in outdoor environments. Coverage analysis and system performance is carried out for a small cell system in the typical urban environment including street canyon simulation scenario. In addition, the beamforming technique is considered to evaluate the throughput improvement. Simulation results show that the mmWave small cell systems is expected to be one of the major candidate technologies to satisfy the requirements of 5G in terms of data rate.

• Journal of Broadcast Engineering
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• v.25 no.6
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• pp.870-881
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• 2020

This paper presents cell ID (cell identity) detection schemes using PSS/SSS (primary synchronization signal/secondary synchronization signal) for 5G NR (new radio) system and evaluates the detection performance. In this paper, we consider two cell ID detection schemes, i.e. two-stage detection and joint detection schemes. The two-stage detection scheme consists of two stages which estimate a channel gain between a transmitter and receiver and detect the PSS and SSS sequences. The joint detection scheme jointly detects the PSS and SSS sequences. In addition, this paper presents coherent and non-coherent combining schemes. The coherent scheme calculates the correlation value for the total length of the given PSS and SSS sequences, and the non-coherent combining scheme calculates the correlation within each group by dividing the total length of the sequence into several groups and then combines them non-coherently. For the detection schemes considered in this paper, the detection error rates of PSS, SSS and overall cell ID are evaluated and compared through computer simulations. The simulation results show that the joint detection scheme outperforms the two-stage detection scheme for both coherent and non-coherent combining schemes, but the two-stage detection scheme can greatly reduce the computational complexity compared to the joint detection scheme. In addition, the non-coherent combining detection scheme shows better performance under the additive white Gaussian noise (AWGN), fixed, and mobile environments.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.6
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• pp.256-263
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• 2007

For $P_B=50Torr,\;P_T=5401Torr,\;T_S=450^{\circ}C,\;{\Delta}T=20K$, Ar=5, Pr=3.34, Le=0.01, Pe=4.16, Cv=1.05, adiabatic and linear thermal profiles at walls, the intensity of solutal convection (solutal Grashof number $Grs=7.86{\times}10^6$) is greater than that of thermal convection (thermal Grashof number $Grt=4.83{\times}10^5$) by one order of magnitude, which is based on the solutally buoyancy-driven convection due to the disparity in the molecular weights of the component A ($Hg_2Cl_2$) and B (He). With increasing the partial pressure of component B from 20 up to 800 Torr, the rate is decreased exponentially. It is also interesting that as the partial pressure of component B is increased by a factor of 2, the rate is approximately reduced by a half. For systems under consideration, the rate increases linearly and directly with the dimensionless Peclet number which reflects the intensity of condensation and sublimation at the crystal and source region. The convective transport decreases with lower g level and is changed to the diffusive mode at $0.1g_0$. In other words, for regions in which the g level is $0.1g_0$ or less, the diffusion-driven convection results in a parabolic velocity profile and a recirculating cell is not likely to occur. Therefore a gravitational acceleration level of less than $0.1g_0$ can be adequate to ensure purely diffusive transport.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.70-77
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• 1999

Purpose : The expression of p53, P211WAF/CIP, Bcl-2, and Bax underlying the radiation-induced apoptosis in different pH environments using SCK mammary adenocarcinoma cell line was investigated. Materials and Methods Mammary adenocarcinoma cells of hi) mice (SCK cells) in exponential growth phase were irradiated with a linear accelerator at room temperature. The cells were irradiated with 12 Gy and one hour later, the media was replaced with fresh media at a different pHs. After Incubation at 37Microbioiogy, College of Medicine Dong A University for 0$\~$48 h, the extort of apoptosis was determined using agarose gel electrophoresis and flow cytometry. The progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. Western blot analysis was used to monitor p53, p211WAFfCIP, Bcl-2, and Bu protein levels. Results : The induction of apoptosis by irradiation in pH 6.6 medium was markedly less than that in pH 7.5 medium. The radiation-induced G2IM arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. Considerable amounts of p53 and p21 proteins already existed at pH 7.5 and increased the level of p53 and p21 significantly after 12 Gy X-irradiation. An incubation at pH 6.6 after 12 Gy X-irradiation did not change the level of p53 and p21 protein levels significantly. Bcl-2 proteins were not significantly affected by radiation and showed no correlation with cell susceptibility to radiation-induced apoptosis in different pHs. An exposure to 12 Gy of X-rays increased the level of Bax protein at pH 7.5 but at pH 6.6, it was slight. Conclusions : The molecular mechanism underlying radiation-induced apoptosis in dinerent pH environments using SCK mammary adenocarcinoma cell line was dependent of the expression p53 and P211YVAF/CIP proteins. We may propose following hypothesis that an acidic stress augments the radiation-induced G2iM arrest, which inhibiting the irradiated cells undergo post-mitotic apoptosis. The effects of environmental acidity on anti-apoptotic and pro-apoptotic function of Bcl-2 family was unclear in SCK mammary adenocarcinoma cell line.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.203-209
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• 2006

For $P_B=50,\;{\Delta}T=10K$, Ar=5, Pr=2.36, Le=0.015, Pe=1.26, Cv=1.11, the intensity of solutal convection (solutal Grashof number $Grs=3.44x10^4$) is greater than that of thermal convection (thermal Grashof number $Grt=1.81x10^3$) by one order of magnitude, which is based on the solutally buoyancy-driven convection due to the disparity in the molecular weights of the component A($Hg_2Cl_2$) and B(He). With increasing the partial pressure of component B from 10 up to 200 Torr, the rate is decreased exponentially. The convective transport decreases with lower g level and is changed to the diffusive mode at 0.1 $g_0$. In other words, for regions in which the g level is 0.1 $g_0$ or less, the diffusion-driven convection results in a parabolic velocity profile and a recirculating cell is not likely to occur. Therefore a gravitational acceleration level of less than 0.1 $g_0$ can be adequate to ensure purely diffusive transport.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.487-498
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• 2016

Leptin, an adipokine predominantly produced from adipose tissue, is well known to induce tumor growth. However, underlying molecular mechanisms are not established yet. While p53 has long been well recognized as a potent tumor suppressor gene, accumulating evidence has also indicated its potential role in growth and survival of cancer cells depending on experimental environments. In the present study, we examined if p53 signaling is implicated in leptin-induced growth of cancer cells. Herein, we demonstrated that leptin treatment significantly increased p53 protein expression in both hepatic (HepG2) and breast (MCF-7) cancer cells without significant effect on mRNA expression. Enhanced p53 expression by leptin was mediated via modulation of ubiquitination, in particular ubiquitin specific protease 2 (USP2)-dependent manner. Furthermore, gene silencing of p53 by small interfering RNA (siRNA) suppressed leptin-induced growth of hepatic and breast cancer cells, indicating the role of p53 signaling in tumor growth by leptin. In addition, we also showed that knockdown of p53 restored suppression of caspase-3 activity by leptin through modulating Bax expression and prevented leptin-induced cell cycle progression, implying the involvement of p53 signaling in the regulation of both apoptosis and cell cycle progression in cancer cells treated with leptin. Taken together, the results in the present study demonstrated the potential role of p53 signaling in leptin-induced tumor growth.

• ETRI Journal
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• v.40 no.1
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• pp.51-60
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• 2018

In Long Term Evolution (LTE) cellular networks, the transmit power control (TPC) mechanism consists of two parts: the open loop (OL) and closed loop. Most cellular networks consider OL/TPC because of its simple implementation and low operation cost. The analysis of OL/TPC parameters is essential for efficient resource management from the cellular operator's viewpoint. In this work, the impact of the OL/TPC parameters is investigated for homogeneous small cells and heterogeneous small-cell/macrocell network environments. A mathematical model is derived to compute the transmit power at the user equipment, the received power at the eNodeB, the interference in the network, and the received signal-to-interference ratio. Using the analytical platform, the effects of the OL/TPC parameters on the system performance in LTE networks are investigated. Numerical results show that, in order to achieve the best performance, it is appropriate to choose ${\alpha}_{small}=1$ and $P_{o-small}=-100dBm$ in a homogenous small-cell network. Further, the selections of ${\alpha}_{small}=1$ and $P_{o-small}=-100dBm$ in the small cells and ${\alpha}_{macro}=0.8$ and $P_{o-macro}=-100dBm$ in the macrocells seem to be suitable for heterogeneous network deployment.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.63-68
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• 2016

This study was performed to assess the microbiological quality of Brassica campestris var. narinosa microgreen from harvesting and processing steps. The samples were analyzed for total viable cell counts (TVC), coliforms, Enterobacteriaceae, Escherichia coli, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Bacillus cereus, and Staphylococcus aureus. The total viable counts of microgreen (whole leaves) and environment samples from harvesting steps were higher than 6.8 log CFU/g and the contamination level of coliforms in the samples were 3.2 log CFU/g and 3.5 log CFU/g of microgreen and soil, respectively. In case of microgreen samples collected from processing steps, the contamination level of TVC and coliforms were higher in raw materials than samples obtained from later stages of processing, i.e. washing, drain, and final products. The contamination levels of B. cereus in raw materials and environments decreased approximately 1.4 log CFU/g in final products. S. aureus was detected in soil samples but Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus and pathogenic E. coli was not detected. In order to identify the sources of contamination for microgreen, the genetic similarity of B. cereus isolates obtained from harvesting and processing steps were compared using the repetitive-sequence-based polymerase chain reaction method. B. cereus isolates obtained from harvesting environments and microgreen were clustered with a similarity greater than 95%. In case of B. cereus isolates obtained from microgreen and environmental samples at processing steps showed low genetic similarity.