• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.390-396
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• 2021

In this research, design and fabrication of marine repeater capable to extend communication coverage in monitoring system of fishing gear automatic identification, which is one of implementation method of the real-name electric fishing gear system declared by Ministry of Oceans and Fisheries in 2016, is reported. The proposed marine repeater is fabricated in a form of RF repeater with interference cancellation system (ICS), which can cancel the oscillation due to feedback signal between service antenna and link antenna. In design process, we secure the isolation of 30 dB between service antenna and link antenna. It is confirmed that when the level of feedback signal into repeater input be lower of 15 dB than repeater gain, error vector magnitude due to oscillation can be lower than the performance criterion of 6%, from the test verification. It is expected that the service coverage will be extended by applying the developed marine ICS RF repeater into marine IoT network including monitoring system of fishing gear automatic identification.

• 한국노년학
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• v.38 no.4
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• pp.1015-1033
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• 2018

The purpose of this study was to examine the meaning and essence of the life of elderly men living alone in public rental housing. Among the phenomenological study methods, the present study used the analysis method proposed by Giorgi(2009). The study participants included 10 elderly men living alone in public rental housing who were recruited through network sampling. The research data were collected through in-depth interviews conducted twice for each person. The results showed that living alone as an elderly man is likened to standing against cold wind out in the wilderness of the world, with living alone deemed a power game between life and death. For the participants, public rental housing is a fence that separates them from the world-the final station of a wandering life. For common people, public rental housing is a stable fence, but for the participants, it is the location of a double-edged solitary life out in the wilderness where the instincts for survival and death play a tug of war. Based on the study findings, the researcher discussed and provided suggestions for psychological housing stability, the disparagement of the elderly in mass media, and countermeasures against psychological isolation.

• Journal of the Korean Society of School Health
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• v.34 no.3
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• pp.179-189
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• 2021

Purpose: The purpose of the study was to investigate health behavior changes in Korean adolescents before and during the COVID-19 pandemic. Methods: A descriptive cross-sectional design was employed. Data were obtained from the 15~16th (2019~2020) Korea Youth Risk Behavior Web-based Survey. Overall, the data of 112,251 students, 57,303 before the COVID pandemic and 54,948 during the pandemic, were included. The data were analyzed using rao-scott 𝝌²-test, t-test, ANCOVA and logistic regression analysis. Results: While sitting time for study decreased, sitting time for leisure increased in the 2020 group compared to the 2019 group. The 2020 group was more likely to skip breakfast and have a higher BMI than the 2019 group. The 2020 group was less likely to consume fruit and engage in moderate and vigorous physical activities than the 2019 group. The 2020 group was less likely to engage in CC, EC, and HTP current smoking and be exposed to secondhand smoke at home, school, and public places than the 2019 group. The 2020 group was more likely to be satisfied with sleep, but less likely to experience stress, depression, suicidal ideation, suicidal plans, and suicidal attempts than the 2019 group. Conclusion: It is necessary to reduce sedentary time, encourage physical activities, manage smoking and drinking rates continuously, and establish a network system to prevent psychological loneliness and isolation for adolescents, which requires participation of experts from the community as a whole.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.475-487
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• 2022

The purpose of this study is to comprehensively examine the facilitators and barriers to social participation of older adults in the society through systematic review of qualitative research. Through PubMed, Embase, Cochrane, data from 2012 to 2022 were collected. The main search keywords were 'elderly', 'older adults', social participation', 'engagement', 'motiv^*', 'barrier', 'facilitat^*'. 7 articles that satisfy the inclusion criteria were selected for analysis. Facilitators and barriers of older adults' social participation were analyzed. The analyzed factors were assorted into 'personal/ internal factors', 'environmental factors', 'social network factors'. The results of this study emphasize not only logistical factors, but also motivation, desire, social context of older adults' as factors to social participation. To prevent older adults' social isolation, a broad understanding of what promotes and inhibits the participation of the older adults is needed.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.3
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• pp.151-159
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• 2022

Purpose : The purpose of this study was to investigate the structural relationships between fear of missing out, addictive tendencies toward social network services (SNSs), and depression in colleges. Methods : The target subjects were students in colleges across gyeongnam & busan, to whom the purpose of the study was explained and who spontaneously agreed to participate. A survey was conducted with 302 participants over 31 days from March 7, 2022, and data from 299 responses was analyzed. Results : 1. Women felt a higher fear of missing out than men. 2. Women showed greater inability to control their use of SNSs, more SNS-related disorders in daily life, and greater immersion in and tolerance of SNSs when compared to men. 3. Women were more depressed than men. 4. Positive correlations were observed between the fear of missing out and SNS-addictive tendencies, between the fear of missing out and depression, and between SNS-addictive tendencies and depression. Conclusion : A comprehensive review of these findings suggests that women had overall higher levels of isolation fear, SNS-addictive tendencies, and depression than men. Based on this, universities should provide gender-specific educational programs around these issues; this student cohort will ultimately work in healthcare, and this kind of awareness will be essential for treating patients. Considering that the current situation poses unusual challenges due to the COVID-19 pandemic, the study's results can serve as basic data for planning educational programs in the future. Over the coming years, comprehensive and continuous education and counselling relating to the fear of missing out, SNS addiction, and depression will be urgently required.

• Earthquakes and Structures
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• v.23 no.2
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• pp.129-138
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• 2022

One of the objectives to prevent building pounding between two adjacentstructures is to considerseparation distance or decrease relative displacement during seismic excitation. Although the majority of building codes around the world have basically suggested some equations or approximately recommended various distances between structuresto avoid pounding hazard, but a lot of reportsin zone of pounding have obviously shown thatsafety situation or economic consideration are not always provided due to the collisions between buildings and the cost of land, respectively. For this purpose, a dynamic MDOF model by having base isolation system is numerically considered and using various earthquake records, relative displacements are mathematically investigated. Different equations to determine the value of damping ratio are collected and the results of evaluations are listed for comparison among them to present a new equation for determination of impact damping ratio. Presented equation is depends significantly on impact velocity before and after impact based on artificial neural network, which the accuracy of them is investigated and also confirmed. In order to select the optimum equation, hysteresisloop of impact between base of building and rubber bumper is considered and compared with the hysteresis loop of each impact, calculated by different equations. Finally, using representative equation, the effect of thickness, number and stiffness of rubber bumpers are numerically investigated. The results of analysis indicate that stiffness and number of bumpers have significantly affected in zone of impact force while the thickness of bumpers have not shown significant influence to calculate impact force during earthquake. For instance, increasing the number of bumpers, gap size between structures and also the value of stiffness is caused to decrease impact force between models. The final evaluation demonstrates that bumpers are able to decrease peak lateral displacement of top story during impact.

• Korean Journal of Culture and Social Issue
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• v.16 no.2
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• pp.147-164
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• 2010

In this paper, we reviewed the community-based approaches to suicide prevention and national strategies for the decrement of suicide rate, and made some suggestions to decrease the suicide rate in South Korea. Until now, efforts to understand and prevent suicide have been pursued singularly by specialized interest groups such as psychiatrists, psychologists, mental health practitioners, and private organizations with little interaction between them, resulting in narrow approaches toward suicide that existed in relative isolation to one another and that have been largely ineffective. To decline the suicide rate in South Korea, the people lived in Korea community ought to have enough knowledge related to suicide and have to cooperate with other people. Through these efforts, Korea community would have established social safety networks to improve the community 's mental health. The most important factor in suicide prevention and declining the suicide rate is reducing the stigma and increase the self-help seeking behaviors associated with suicide and mental health. Therefore, suicide is not an individual problem solved by suicidal patient, but a community's problem solved by community in recognizing, managing and preventing suicide.

• IMMUNE NETWORK
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• v.22 no.6
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• pp.49.1-49.15
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• 2022

Exosomes derived from mesenchymal stem cells (MSCs) could protect against myocardial infarction (MI). TLR4 is reported to play an important role in MI, while microRNA-182-5p (miR-182-5p) negatively regulates TLR4 expression. Therefore, we hypothesize that MSCs-derived exosomes overexpressing miR-182-5p may have beneficial effects on MI. We generated bone marrow mesenchymal stem cells (BM-MSCs) and overexpressed miR-182-5p in these cells for exosome isolation. H₂O₂-stimulated neonatal mouse ventricle myocytes (NMVMs) and MI mouse model were employed, which were subjected to exosome treatment. The expression of inflammatory factors, heart function, and TLR4 signaling pathway activation were monitored. It was found that miR-182-5p decreased TLR4 expression in BM-MSCs and NMVMs. Administration of exosomes overexpressing miR-182-5p to H₂O₂-stimulated NMVMs enhanced cell viability and suppressed the expression of inflammatory cytokines. In addition, they promoted heart function, suppressed inflammatory responses, and de-activated TLR4/NF-κB signaling pathway in MI mice. In conclusion, miR-182-5p transferred by the exosomes derived from BM-MSCs protected against MI-induced impairments by targeting TLR4.

• IMMUNE NETWORK
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• v.21 no.6
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• pp.39.1-39.18
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• 2021

The high virulent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that emerged in China at the end of 2019 has generated novel coronavirus disease, coronavirus disease 2019 (COVID-19), causing a pandemic worldwide. Every country has made great efforts to struggle against SARS-CoV-2 infection, including massive vaccination, immunological patients' surveillance, and the utilization of convalescence plasma for COVID-19 therapy. These efforts are associated with the attempts to increase the titers of SARS-CoV-2 neutralizing Abs (nAbs) generated either after infection or vaccination that represent the body's immune status. As there is no standard therapy for COVID-19 yet, virus eradication will mainly depend on these nAbs contents in the body. Therefore, serological nAbs neutralization assays become a requirement for researchers and clinicians to measure nAbs titers. Different platforms have been developed to evaluate nAbs titers utilizing various epitopes sources, including neutralization assays based on the live virus, pseudovirus, and neutralization assays utilizing recombinant SARS-CoV-2 S glycoprotein receptor binding site, receptor-binding domain. As a standard neutralization assay, the plaque reduction neutralization test (PRNT) requires isolation and propagation of live pathogenic SARS-CoV-2 virus conducted in a BSL-3 containment. Hence, other surrogate neutralization assays relevant to the PRNT play important alternatives that offer better safety besides facilitating high throughput analyses. This review discusses the current neutralization assay platforms used to evaluate nAbs, their techniques, advantages, and limitations.

• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.1-14
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• 1998

In this paper, Antenna, LNA, Mixer, VCO, and Modulation/Demodulation in Baseband processor which are the RF main components in Wireless LAN system for ultra high-speed communications network are studied. Antenna bandwidth and selective fading due to multipath can be major obstacles in high speed digital communications. To solve this problem, wide band MSA which has loop-structure magnetic antenna characteristics is designed. Distributed mixer using dual-gate GaAs MESFET can achieve over 10dB LO/RF isolation without hybrid, and minimize circuit size. As linear mixing signal is produced, distortions can be decreased at baseband signals. Conversion gain is achieved by mixing and amplification simultaneously. Mixer is designed to have wide band characteristics using distributed amplifier. In VCO design, Oscillator design method by large signal analysis is used to produce stable signal. Modulation/Demodulation system in baseband processor, DS/SS technique which is robust against noise and interference is used to eliminate the effect of multipath propagation. DQPSK modulation technique with M-sequences for wideband PN spreading signals is adopted because of BER characteristic and high speed digital signal transmission.