• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.710-720
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• 2009

The Future Generation Networks(FGNs) are proposed to integrate various heterogeneous access technologies, and further expected to support both vertical and seamless handovers. In this motivation, the IEEE 802.21 specifies Media Independent Handover(Mlli) services to enhance the mobile user experience by optimizing handovers between heterogeneous access networks. Additionally, Fast handover for MIPv6(FM1Pv6) is introduced to provide transparent host mobility and to improve handover performance by reducing handover delay as well. This paper focuses on the coordination of FMIPv6 and MIH, and introduces an enhanced mobility management framework suited for FGN. This novel framework replaces handover signaling messages used in wireless networks with novel MIH messages and local primitives. Moreover, Serving Access Router(SAR) performs most of handover processes instead of Mobile Node(MN). Therefore, the proposed mobility management framework reduces handover latency, packet loss, and signaling overhead significantly. We further evaluate the performance of the proposed framework by using both numerical analysis and network simulations.

• The Journal of the Acoustical Society of Korea
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• v.31 no.8
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• pp.542-550
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• 2012

In this paper, an adaptive scheme for network topology configuration is proposed to save the overall energy consumption in underwater acoustic sensor network. The proposed scheme employs a self-organized networking methodology where network topology is locally optimized by exchanging the energy-related information between neighboring nodes such as the remaining energy of each node, in a way that the network life time can be augmented without any centralized control function. Computer simulation is used to evaluate the proposed scheme comparing with LEACH in terms of the number of alive nodes after a given time, the deviation of individual nodes' residual energy and the energy consumption at the initialization and coordination stages.

• Steel and Composite Structures
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• v.28 no.1
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• pp.39-49
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• 2018

The concrete bridge decks are usually precast and in-situ assembled with steel girders with post-pouring joint in the construction practice of super-wide steel-concrete composite beam. But the difference of concrete age between the precast slabs and the post-pouring joint has been not yet considered for the long-term performance analysis of this kind composite beam. A simply supported precast-assembled T-shaped beam was taken as an example to analyze the long-term performance of steel-concrete composite beam with post-pouring joint. Based on the deformation coordination conditions of the old-new concrete deck and steel girder, a theoretical model for the long-term behavior of precast-assembled composite beam is proposed in this paper according to age-adjusted effective modulus method. Then, the feasibility of the proposed model is verified by the available test data from the Gilbert's composite beams. Parametric studies were preformed to evaluate the influences of the cross-sectional area ratio of the post-pouring joint to the whole bridge deck, as well as the difference of concrete age between the precast slabs and the post-pouring joint, on the long-term performance of the composite beam. The results indicate that the traditional method without considering the age difference would seriously underestimate the effect of creep and shrinkage of concrete bridge decks. The concrete age difference between the precast slabs and the post-pouring joint should be demonstrated for the life cycle design and long-term performance analysis of precast-assembled steel-concrete composite beams.

• Korean Journal of Medicinal Crop Science
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• v.16 no.3
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• pp.173-182
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• 2008

Prunus sargentii of Rosaceae familiy, has been reported to have radical scavenging activity and anti-inflammatory effect. On these facts, this research was conducted to evaluate pharmaceutical activities of the bark extracts P. sargentii. Free radical scavenging activities of fraction (Fr) -5${\sim}$10 isolated from P. sargentii was higher than 80% respectively at 10ppm. The superoxide dismutase (SOD)-like activity of Fr-5, 9 were about 97, 84%, respectively at 1,000 ppm. Xanthine oxidase inhibitory effect of Fr-9, 10 were about 75, 78%, respectively at 1,000 ppm. The tyrosinase inhibitory effect related to skin-whitening was 72, 68% in Fr-2, 9 isolated from Prunus sargentii R. at 1,000 ppm. Hyaluronidase inhibition activity related to the anti-inflammation effect was 98% for Fr-8 at 500 ppm. Isolation of the methanol soluble fraction from P. sargentii yielded two major phenol compounds, (-)-epicatechin and taxifolin. The structure of the compound was certainly determined by chemical analyses, as well as NMR and Mass spectroscopy. The present study was carried out in a search for new cosmetic material from the bark from P. sargentii. and, (-)-epicatechin and taxifolin were isolated as active principles. So P. sargentii R. methanolic extracts may be used for the cosmetic material.

• Convergence Security Journal
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• v.17 no.2
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• pp.89-100
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• 2017

Last January 2017, Donald Trump was inaugurated as the 45th president of the United States. He actively claimed a priority for the United States, which is referred as America First, during his presidential campaign. However, his political assertions turned out to be as Isolationist in terms of foreign policy. It becomes a serious problem for South Korea because South Korea is solely dependent on the U.S. "Extended Deterrence" of North Korea's nuclear threats. In other words, there will be a higher likelihood for North Korea to misinterpret the relationship between South Korea and the U.S. Due to his foreign policy, there is a possible provocation by North Korea. Therefore, ROK-U.S. Alliance, the model of Asymmetry Alliance in order to prepare for North Korea's nuclear provocation, will be evaluated through America's perspective based on "Autonomy-Security Trade-off Model". For this purpose, this research will evaluate ROK-U.S. Alliance with regards to a threat perception, policy coordination, and a value as an ally. Based on the evaluation, it will deduce tactical implications of South Korea's alliance.

• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.89-105
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• 2021

In this paper, feasibility study was carried out to evaluate necessity of seismic design of earth retaining structures in a deep excavation. Dynamic behavior of retaining system was analyzed using FLAC, a finite difference analysis program. It was shown that maximum bending moments of retaining walls and axial forces of supports were increased up to 98% and 87% during earthquake, respectively, compared to final excavation step, which indicates that dynamic earth pressure has a large effect on a retaining system. The stability of retaining system designed according to current design specifications was evaluated using structural forces obtained by numerical analysis, and effect of earthquake loading on structural design was analyzed.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.979-985
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• 2020

A wide range of techniques have been developed to separate X or Y- chromosome-bearing sperm. In particular, bovine semen sex-sorted by using flow cytometry based on differences in the amount of DNA between X and Y chromosome bearing sperm is used in dairy farms. The first piglets were produced using sex-sorted sperm 30 years ago. However, sexed sperm have not been commercially available in pigs because the flow cytometry technique is not capable of sorting the high number of sperm required for porcine artificial insemination (AI), and the prolonged exposure to an electrical filed might damage to the DNA in sperm. The purpose of this study was to evaluate a boar sperm sorting method based on magnetic nanoparticles. A flow cytometer assay verified the efficacy of the magnetic nanoparticles (> 90% of sex-sorted sperm). In addition, a duplex polymerase chain reaction (PCR) assay using sex chromosome specific genes including SRY (sex-determining region Y; male), ZFY (zinc finger protein Y-linked; male), and ZFX (zinc finger protein X-linked; female) showed that in vitro fertilized porcine embryos by X and Y-chromosome bearing sperm were 100% female (40/40) and 72% female (35/48), respectively, at 8-cell or morula stages, suggesting that the sex-sorted sperm were fertile. In conclusion, our findings suggest that the sex-sorted method based on magnetic nanoparticles can be utilized for porcine sex-sorted AI.

• Korean Journal of Plant Resources
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• v.34 no.6
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• pp.575-599
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• 2021

The edible roots of radish (Raphanus sativus L.) are consumed worldwide. For characterization and evaluation of the agronomic traits and health-promoting chemicals in radish germplasms, new germplasm breeding materials need to be identified. The objectives of this study were to evaluate the phenotypic traits and glucosinolate contents of radish roots from 110 germplasms, by analyzing correlations between 10 quantitative phenotypic traits and the individual and total contents of five glucosinolates. Phenotypic characterization was performed based on descriptors from the UPOV and IBPGR, and glucosinolate contents were analyzed using liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode (MRM). Regarding the phenotypic traits, a significant correlation between leaf length and root weight was observed. Glucoraphasatin was the main glucosinolate, accounting for an average of 71% of the total glucosinolates in the germplasms; moreover, its content was significantly correlated with that of glucoerucin, its precursor. Principal component analysis indicated that the 110 germplasms could be divided into five groups based on their glucosinolate contents. High levels of free-radical scavenging activity (DPPH) were observed in red radishes. These results shed light on the beneficial traits that could be targeted by breeders, and could also promote diet diversification by demonstrating the health benefits of various germplasms.

• Research in Community and Public Health Nursing
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• v.32 no.4
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• pp.540-554
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• 2021

Purpose: Most of the currently used concepts and measurements of social support have been relevant for general population. The main purpose of this study is to conduct the concept analysis of perceived social support(PSS) of family caregivers for people with dementia. Methods: This study adopted the Walker and Avant concept analysis methodology. Results: Findings from this concept analysis suggested four defining attributes of PSS of family caregivers for people with dementia: 1) PSS is help or assistance that family caregivers perceive as available when needed; 2) PSS is offered through socio-ecological structure; 3) PSS has a specific function to meet the needs of family caregivers; and 4) PSS includes quality aspects where family caregivers choose, use, or evaluate it. Borrowing from the socio-ecological model, this study proposed the structural aspects of PSS. This study also identified functional aspects of PSS, such as emotional support, informational support, appraisal support, and practical support. Finally, this study assessed quality aspects of PSS, such as satisfaction, timeliness, usefulness, accessibility, and coordination. Conclusion: Focusing on family caregivers for people with dementia, we proposed a new model of PSS. The present study helped refine and clarify the concept of PSS of family caregivers for people with dementia. The results of this study may also contribute to promoting the development of more effective instruments for the concept.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.438-448
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• 2023

The concentrations of trace metals and organic matters in marine sediments collected from southeast Korean coastal areas were investigated. The primary purpose of this study was to evaluate the contamination status, spatial distribution and potential ecological risks associated with the physiochemical composition in the studied areas. We found that the concentrations of trace metals in marine sediments were as follows: Fe > Mn > Zn > Cr > Pb > Cu > As > Cd > Hg. According to the sediment quality guidelines (SQGs) of Korea, concentrations of Zn, Cr, Cu and Cd at all sampling sites were below threshold effect levels (TEL). However, concentrations of As, Hg, and Pb (i.e., at the 94-98% of sampling sites), were below the TEL. In addition, concentration factors (CF) in the surveyed area were found to be associated with low ecological risks, whereas As, Hg, and Cu showed moderate to high risk levels in some inner parts of the studied bays. Finally, the pollution load index (PLI) and ecological risk index (ERI) of the elucidated metals were linked to moderate ecological risk, pointing to the possibility of being deleterious to some benthic organisms.