• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.389-395
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• 2011

Since Elliptic Curve Cryptosystems(ECCs) support the same security as RSA cryptosystem and ElGamal cryptosystem with 1/6 size key, ECCs are the most efficient to smart cards, cellular phone and small-size computers restricted by high memory capacity and power of process. In this paper, we explicitly explain methods for finite fields operations used in ECC, and then construct some composite fields over finite fields which are secure under Weil's decent attack and maximize the speed of operations. Lastly, we propose a fast multiplier over our composite fields.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.288.1-288.1
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• 2002

Herbal medicines are increasingly being utilized to treat a wide variety of disease processes. The aim of this study was to evaluate the ability of aqueous extract from the roots of Platycodon grandiflorum A. DC (Campanulaceae). Changkil (CK). to affect cellular response in primary cultures of rat hepatocytes to t-butyl hydroperoxide (t-BHP) induced oxidative stress and hepatotoxicity. CK-treated cells showed an increased resistance to oxidative challenge. as revealed by a higher percent of survival capacity in respect to control cells. CK added prior or simultaneously with I-BHP reduced enganced lipid peroxidation measured as production of malondialdehyde and enhnaced intracellular reduced glutathinoe depletion by t-BHP. Furhtermore. CK protected from the t-BHP-induced intracellular generation of reactive oxygen species assessde by montioting dichlorodihydrofluorescein fluorescence. it can be concluded that CK exerts an antioxidant action insice the cell. responsible for the abserved modulation of the cellular response to oxidative challenge. and CK have a marked anitioxdative and hepatoprotective potency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.900-909
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• 2000

Adaptive array antennas are one of the most promising techniques for improving the capacity of CDMA mobile communication system. In this paper, the uplink and downlink capacity for asynchronous W-CDMA system with adaptive array antenna is analyzed when an angle estimation error is present. From the results, it is found that the capacities are decreased by the angle estimation error. Specifically, when 5 degrees of error is present at 9 element adaptive array, the capacities are found to decrease by 5.2% in the uplink and 11.6% in the downlink. Also, in this paper, an attempt for comparing the capacities on different channel environments has been made. However, it is found that the increase of the Rice factor hardly effects the capacity due to the power control.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6851-6856
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• 2013

In the present report we determined the protective capacity of grapefruit juice (GJ) against molecular and cellular damage in azoxymethane (AOM) treated mice. Animals were daily administered GJ orally (0.8, 4.1, and 8.2 ${\mu}l/g$) for seven weeks, as well as intraperitoneally (ip) injected with AOM twice (weeks 2 and 3 of the assay). Control groups administered with water, with the high dose of GJ, and with AOM injected in weeks 2 and 3 were also included. The results showed a significant, dose-dependent protection of GJ on the number of colon aberrant crypts (AC) induced by AOM. The highest inhibitory effect was reached with the highest tested dose of GJ, decreasing ACF by 51% and 43% at weeks 4 and 7 of the assay. Regarding protein and lipid oxidation we also found a dose-dependent decrease caused with GJ in comparison with the increased levels produced by AOM. Therefore, our results established chemopreventive potential for GJ, and suggested effects related to its antioxidant capacity. Finally, we found that the tested agents induced neither micronuclei increase nor alteration in bone marrow cytotoxicity.

• Journal of Ginseng Research
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• v.41 no.2
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• pp.169-179
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• 2017

Background: Ginsenosides are the main pharmacological components of Panax ginseng root, which are thought to be primarily responsible for the suppressing effect on oxidative stress. Methods: 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and oxygen radical absorption capacity were applied to evaluate the antioxidant activities of the ginsenosides. Human embryonic kidney 293 (HEK-293) cells were incubated with ginsenosides extracted by pulsed electric field (PEF) and solvent cold soak extraction (SCSE) for 24 h and then the injury was induced by $40{\mu}M$ $H_2O_2$. The cell viability and surface morphology of HEK-293 cells were studied using MTS assay and scanning electron microscopy, respectively. Dichloro-dihydro-fluorescein diacetate fluorescent probe assay was used to measure the level of intracellular reactive oxygen species. The intracellular antioxidant activities of ginsenosides were evaluated by cellular antioxidant activity assay in HepG2 cells. Results: The PEF extracts displayed the higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and stronger oxygen radical absorption capacity (with an oxygen radical absorption capacity value of $14.48{\pm}4.04{\mu}M\;TE\;per\;{\mu}g/mL$). The HEK-293 cell model also suggested that the protective effect of PEF extracts was dose-dependently greater than SCSE extracts. Dichloro-dihydro-fluorescein diacetate assay further proved that PEF extracts are more active (8% higher than SCSE extracts) in reducing intracellular reactive oxygen species accumulation. In addition, scanning electron microscopy images showed that the HEK-293 cells, which were treated with PEF extracts, maintained more intact surface morphology. Cellular antioxidant activity values indicated that ginsenosides extracted by PEF had stronger cellular antioxidant activity than SCSE ginsenosides extracts. Conclusion: The present study demonstrated the antioxidative effect of ginsenosides extracted by PEF in vitro. Furthermore, rather than SCSE, PEF may be more useful as an alternative extraction technique for the extraction of ginsenosides with enhanced antioxidant activity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1091-1101
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• 2012

Device-to-device (D2D) communication is expected to offer local area services with low transmit power and short link distance, even not via any infrastructures. These advantages will lead to the deployment of D2D systems in a massive scale, where the order of magnitude of D2D user density is higher than that of cellular user density. Network-assisted D2D systems, where D2D resources are managed by cellular networks, are unable to support the large number of D2D devices, due to the signaling overhead for control signals. In this case, no coordination can be an answer. This paper considers uncoordinated D2D systems, which is implemented with a number of D2D devices in a large scale. By analyzing the transmission capacity of D2D systems, we found a feasibility condition under which the uncoordinated D2D communications possibly coexist within cellular networks, sharing the uplink spectrum. In addition, we provide guidelines for the operational points of massive D2D communications, giving some knowledge about proper transmit power level and link distance of uncoordinated D2D.

• Journal of Internet Computing and Services
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• v.24 no.1
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• pp.1-7
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• 2023

Recently, the technology of device-to-device(D2D) communication has been receiving big attention to improve the system performance since the amount of high quality/large capacity data traffic from smart phones and various devices of Internet of Things increase rapidly in 5G/6G based next generation cellular networks. However, even though the system performance of macro cells increase by reusing the frequency, the performance of macro user equipments(MUEs) decrease because of the strong interference from D2D user equipments(DUEs). Therefore, this paper proposes a dynamic channel management(DCM) scheme for DUEs to guarantee the performance of MUEs as the number of DUEs increases in next generation downlink cellular networks. In the proposed D2D DCM scheme, macro base stations dynamically assign subchannels to DUEs based on the interference information and signal to interference and noise ratio(SINR) of MUEs. Simulation results show that the proposed D2D DCM scheme outperforms other schemes in terms of the mean MUE capacity as the threshold of the SINR of MUEs incareases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1619-1629
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• 2016

We study an efficient transmission protocol for the cellular-aided device-to-device communication model. In particular, two source-destination pairs communicate with the help of unlink and downlink cellular links. For the proposed scheme, two transmitters send their messages and the base station and two receivers receive at the first phase. Then, at the second phase, the base station sends the XOR of the messages to two receivers and they try to decode their own messages from the received signals after the first and second phases. We analyze the outage-based throughput achievable by the proposed scheme and demonstrate by simulations that the proposed scheme provides an improved outage performance compared to the conventional device-to-device communication schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.393-402
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• 2017

Just like terrestrial cellular networks, underwater cellular communication networks, which can manage the overall network resource by adaptively allocating backhaul resource for each base station according to its ingress traffic, are necessary. In this paper, a new resource allocation protocol is proposed for the underwater cellular communication network, allocating backhaul resource of a base station proportional to its ingress traffic to the base station. This protocol is classified into two types dependent upon allocation period: the resource allocation protocol with adaptive period and that with fixed period. In order to determine a proper resource allocation protocol, the performance of the two protocols, in terms of reception rate, message overhead, and latency is compared and investigated via simulation. As a result, the resource protocol with adaptive period outperforms that with fixed period; the resource allocation protocol with fixed period results in a maximum of $10^2$ order longer queueing delay as well as $10^2$ order greater message overhead than that with adaptive period.

• Molecules and Cells
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• v.37 no.9
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• pp.650-655
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• 2014

Mesenchymal stem cells (MSCs) can differentiate into neural cells to treat nervous system diseases. Magnetic resonance is an ideal means for cell tracking through labeling cells with superparamagnetic iron oxide (SPIO). However, no studies have described the neural differentiation ability of SPIO-labeled MSCs, which is the foundation for cell therapy and cell tracking in vivo. Our results showed that bone marrow-derived mesenchymal stem cells (BM-MSCs) labeled in vitro with SPIO can be induced into neural-like cells without affecting the viability and labeling efficiency. The cellular uptake of SPIO was maintained after labeled BM-MSCs differentiated into neural-like cells, which were the basis for transplanted cells that can be dynamically and non-invasively tracked in vivo by MRI. Moreover, the SPIO-labeled induced neural-like cells showed neural cell morphology and expressed related markers such as NSE, MAP-2. Furthermore, whole-cell patch clamp recording demonstrated that these neural-like cells exhibited electrophysiological properties of neurons. More importantly, there was no significant difference in the cellular viability and $[Ca^{2+}]_i$ between the induced labeled and unlabeled neural-like cells. In this study, we show for the first time that SPIO-labeled MSCs retained their differentiation capacity and could differentiate into neural-like cells with high cell viability and a good cellular state in vitro.