• Journal of Internet Computing and Services
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• v.22 no.5
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• pp.35-45
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• 2021

The purpose of this study is to understand the characteristics and trends of active senior. As the baby boom generation become the age of the elderly, they are more active than senior. These seniors are called active seniors, a new consumer group. Many countries and companies are also interested in providing relevant policies and services, but there is lack of researches on active senior trends. This study collects the 8,740 posts related to active seniors on social media from January 1st, 2018 to June 31st, 2021, and conducted keyword frequency analysis, TF-IDF analysis and LDA topic modeling. Through LDA topic modeling, topics are classified into 10 categories: lifestyle, benefits, shopping, government business, government education, health, society and economy, care industry, silver housing, leisure. The results of this study can be utilized as fundamental data to help understand the academic and industrial aspects of active senior.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2699-2708
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• 2020

Helical-coil steam generator (HCSG) technology is a major design candidate for small modular reactors due to its compactness and capability to produce superheated steam with high generation efficiency. In this paper, we investigate the feasibility of the passively autonomous power maneuvering by coupling the 3-D transient multi-physics of a soluble-boron-free (SBF) core with a time-dependent HCSG model. The predictor corrector quasi-static method was used to reduce the cost of the transient 3-D neutronic solution. In the numerical system simulations, the feedwater flow rate to the secondary of the HCSGs is adjusted to extract the demanded power from the primary loop. This varies the coolant temperature at the inlet of the SBF core, which governs the passively autonomous power maneuvering due to the strongly negative coolant reactivity feedback. Here, we simulate a 100-50-100 load-follow operation with a 5%/minute power ramping speed to investigate the feasibility of the passively autonomous load-follow in a 450 MW_th SBF PWR. In addition, the passively autonomous frequency control operation is investigated. The various system models are coupled, and they are solved by an in-house Fortran-95 code. The results of this work demonstrate constant steam temperature in the secondary side and limited variation of the primary coolant temperature. Meanwhile, the variations of the core axial shape index and the core power peaking are sufficiently small.

• Animal Bioscience
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• v.34 no.5
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• pp.789-800
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• 2021

Objective: Conservation and genetic improvement of cattle breeds require information about genetic diversity and population structure of the cattle. In this study, we investigated the genetic diversity and population structure of the three cattle breeds in the Korean peninsula. Methods: Jeju Black, Hanwoo, Holstein cattle in Korea, together with six foreign breeds were examined. Genetic diversity within the cattle breeds was analyzed with minor allele frequency (MAF), observed and expected heterozygosity (HO and HE), inbreeding coefficient (FIS) and past effective population size. Molecular variance and population structure between the nine breeds were analyzed using a model-based clustering method. Genetic distances between breeds were evaluated with Nei's genetic distance and Weir and Cockerham's FST. Results: Our results revealed that Jeju Black cattle had lowest level of heterozygosity (HE = 0.21) among the studied taurine breeds, and an average MAF of 0.16. The level of inbreeding was -0.076 for Jeju Black, while -0.018 to -0.118 for the other breeds. Principle component analysis and neighbor-joining tree showed a clear separation of Jeju Black cattle from other local (Hanwoo and Japanese cattle) and taurine/indicine cattle breeds in evolutionary process, and a distinct pattern of admixture of Jeju Black cattle having no clustering with other studied populations. The FST value between Jeju Black cattle and Hanwoo was 0.106, which was lowest across the pair of breeds ranging from 0.161 to 0.274, indicating some degree of genetic closeness of Jeju Black cattle with Hanwoo. The past effective population size of Jeju Black cattle was very small, i.e. 38 in 13 generation ago, whereas 209 for Hanwoo. Conclusion: This study indicates genetic uniqueness of Jeju Black cattle. However, a small effective population size of Jeju Black cattle indicates the requirement for an implementation of a sustainable breeding policy to increase the population for genetic improvement and future conservation.

• Journal of Ginseng Research
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• v.45 no.6
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• pp.706-716
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• 2021

Background: Irritable bowel syndrome (IBS), the most common functional gastrointestinal disorder, is characterized by chronic abdominal pain and bowel habit changes. Although diverse complicated etiologies are involved in its pathogenesis, a dysregulated gut-brain axis may be an important factor. Red ginseng (RG), a traditional herbal medicine, is proven to have anti-inflammatory effects and improve brain function; however, these effects have not been investigated in IBS. Methods: Three-day intracolonic zymosan injections were used to induce post-infectious human IBS-like symptoms in mice. The animals were randomized to receive either phosphate-buffered saline (CG) or RG (30/100/300 mg/kg) for 10 days. Amitriptyline and sulfasalazine were used as positive controls. Macroscopic scoring was performed on day 4. Visceral pain and anxiety-like behaviors were assessed by colorectal distension and elevated plus maze and open field tests, respectively, on day 10. Next-generation sequencing of gut microbiota was performed, and biomarkers involved in gut-brain axis responses were analyzed. Results: Compared to CG, RG significantly decreased the macroscopic score, frequency of visceral pain, and anxiety-like behavior in the IBS mice. These effects were comparable to those after sulfasalazine and amitriptyline treatments. Moreover, RG significantly increased the proliferation of beneficial microbes, including Lactobacillus johnsonii, Lactobacillus reuteri, and Parabacteroides goldsteinii. RG significantly suppressed expression of IL-1β and c-fos in the gut and prefrontal cortex, respectively. Further, it restored the plasma levels of corticosterone to within the normal range, accompanied by an increase in adrenocorticotropic hormone. Conclusion: RG may be a potential therapeutic option for the management of human IBS.

• Health Policy and Management
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• v.29 no.2
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• pp.160-171
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• 2019

Background: This study purposed to compare the difference on medical utilization and health expenditure of baby boomer generation by depression between gender. Methods: Korea Welfare Panel Survey 2016, provided by the Korea Institute for Health and Social Affairs, was used for the analysis. For the research, we used the two-part model, yes or no of use (part 1), and frequency of use (part 2) for medical utilization. The dependent variables are the whether or not to use of hospitalization services, outpatient services, length of stay, outpatient service visits, and health expenditure. And the independent variables are used as the predisposing (education, spouse presence), enabling (insurance type, private insurance, economic activity, income), and need (chronic disease, self-rated health, disability) factors in the Andersen behavior model. Depression was used as intervening variables. Structural equation model and multiple group analysis by gender were used. Results: There were differences in the medical care usage and cost between men and women in baby boomer. For men, mediating effects of depression were present at the hospitalization (yes/no), length of stay, and health expenditure. On the other hand, for women, the mediating effect of depression was found only at the outpatient visits. Specially, depression was working at the medical services by the different way between gender. The size of effect (multiple group analysis) was affected by significant differences between men and women. Conclusion: This study found that the mediating effect of depression is increased medical usage and health expenditure and the effect factors are different by gender. Therefore, it is necessary to establish a medical care policy considering the socio-economic characteristics of baby boomers.

• The Research Journal of the Costume Culture
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• v.27 no.4
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• pp.384-397
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• 2019

The purpose of this study is to analyze the eco-friendly design characteristics of contemporary children's collections. Photos from FirstviewKorea were utilized for analysis; 29 brands were selected that included children's clothing collections featuring eco-friendly characteristics from 2007 to 2018. The results are as follows. First, naturalness was the most frequent characteristic of environmentally friendly children's collections. It was not conveyed in an eccentric way in any season, showed a relatively uniform distribution, and was seen in various ways, including printed on the fabric and expressed in $appliqu\acute{e}s$ and embroidery. Second, handcrafted features frequently changed according to seasonal trends. Various methods such as beading, embroidery, applique, sewing techniques, and handbags were used, which enhanced manual workability, discrimination from other designs. Third, traditionality is divided into the characteristics of ethnicity and revivalism. National traditions were expressed in the clothing and reflected the current generation while connecting to the past. Fourth, simplicity appeared in classic designs such as simple silhouettes, sparse decoration, natural colors, and comfortable dress length that is not tight on the body. Simplicity was not a frequent feature due to the characteristics of the children's clothing collections. Fifth, playfulness functioned to enhance the children's clothing's wear frequency. Although it was the least frequent of all the characteristics, it seemed to increase the design fun and the clothing's value by fusing with other characteristics such as handcraftedness and naturalness.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.233-239
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• 2019

The purpose of this study was to investigate the knowledge and awareness about radiation use among non - radiation undergraduates. This analysis were used based on the collected questionnaires with Frequency, mean and standard deviation, t-test, one-way ANOVA. As a result, there was no significant difference between the groups in terms of gender and age. There were statistical differences in some items in the major field. In addition, the perception of radiation was more negative in women and under 25 years of age (p<0.05). The correlations between the sub - factors showed that the higher the knowledge of radiation, the higher the perception of knowledge and use of radiation. It is believed that university students will have a positive effect of contributing to the development of the radiation industry if they have a correct understanding of radiation because they are more likely to contribute to public opinion by advancing into society.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.66-69
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• 2016

In this paper, we suggests a Ka-band LNB considering next-generation UHD satellite TVRO. Since Ka-band has grater attenuation than Ku-band in atmosphere, we designed the low-noise down-converter to improve receiving sensitivity and to extend a dynamic range of receiver. It aims to compensate a quality of ultra high definition transmission signal for rainfall. The low-noise block diagram consists of a three-staged amplifier (LNA), band-pass filter for deleting image (BPF), mixer and IF when considering nonlinear characteristics in the receiver RF front end module. Also, we showed a LNB through optimization processes affecting dynamic range directly in receiver FEM. Asa resuly of experiment, the gain of low-noise down-converter show between 58.5dB and 60.7dB, the noise figure has a high characteristic as 1.38dB. Finally, the phase noise of local oscillator is -63.10dBc at 100MHz offset frequency.

• The Research Journal of the Costume Culture
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• v.27 no.5
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• pp.461-478
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• 2019

As the concept of "marriage age" gradually disappears, the consumption class of the wedding market includes not only X and Y generations but also Z generations, and each generation has its own characteristics as it is already known, and there are differences in the consumption. So this research analyzed age-related behavior differences in both awareness of and preparation for marriage. Three hundred sixteen unmarried Korean males and females comprised the study population and data was collected from March 5, 2019, to April 3, 2019. The SPSS Statistics 23.0 Package was used for analysis, specifically the functions of frequency, cross tabulation, factor analysis, chi-squared test, Cronbach's alpha, Duncans's new multiple range test (MRT), and analysis of variance (ANOVA). Marriage motivation was analyzed by three factors, and there were significant differences in two types. Marital involvement was analyzed by two factors, and both factors showed significant age-related differences. Concerns relating to marriage preparation were analyzed by four factors, and two varied according to respondent age. Regarding marriage preparation behaviors, the analysis revealed that the marriage preparation method appreciably differed between age groups. Our analysis also found significant age-related differences in "the main media usually used to acquire information" and "the paths preferred for acquiring information in preparing for marriage". We expect that study results will be useful for identifying new research directions, understanding the dimensions of the wedding industry, and developing related marketing strategies.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.642-649
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• 2018

The effect of gas sparging on sonochemical oxidation was investigated in a 300 kHz sonoreactor under various liquid height/volume conditions ($5{\sim}30{\lambda}$, 3.4 ~ 9.0 L), determined by the wavelength of the applied frequency. The electrical input power was maintained constant for all cases . Sonochemical activity drastically decreased from $15{\lambda}$ and the liquid height of $10{\lambda}$ was suggested as the optimal height for 300 kHz without gas sparging. In our previous research, the sonochemical activity observed was five-times higher when air sparging was applied for 36 kHz. On the other hand, no enhancement was obtained at 10, 15, 25 and $30{\lambda}$ using air sparging (1, 3, and 6 L/min) for 300 kHz in this study $20{\lambda}$ and optimization of gas sparging was conducted at $20{\lambda}$ using various gases including air, Ar, $O_2$, $N_2$, and mixtures of Ar and $O_2$. It was found that gas sparging using pure Ar or pure $O_2$ resulted in lower sonochemical activity compared to that of air sparging due to the imbalance between the intensity of cavitation phenomena and the generation of oxidizing radical species. Consequently, the gas mixture of $Ar:O_2$ = 80 % : 20 % (DO saturation ${\approx}100%$) was suggested as an optimal gas sparging condition.