• Journal of Internet Computing and Services
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• v.24 no.1
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• pp.71-86
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• 2023

The purpose of this exploratory study is to compare the differences in public perceptual characteristics of Korean and Chinese societies regarding the metaverse using big data analysis. Due to the environmental impact of the COVID-19 pandemic, technological progress, and the expansion of new consumer bases such as generation Z and Alpha, the world's interest in the metaverse is drawing attention, and related academic studies have been also in full swing from 2021. In particular, Korea and China have emerged as major leading countries in the metaverse industry. It is a timely research question to discover the difference in social awareness using big data accumulated in both countries at a time when the amount of mentions on the metaverse has skyrocketed. The analysis technique identifies the importance of key words by analyzing word frequency, N-gram, and TF-IDF of clean data through text mining analysis, and analyzes the density and centrality of semantic networks to determine the strength of connection between words and their semantic relevance. Python 3.9 Anaconda data science platform 3 and Textom 6 versions were used, and UCINET 6.759 analysis and visualization were performed for semantic network analysis and structural CONCOR analysis. As a result, four blocks, each of which are similar word groups, were driven. These blocks represent different perspectives that reflect the types of social perceptions of the metaverse in both countries. Studies on the metaverse are increasing, but studies on comparative research approaches between countries from a cross-cultural aspect have not yet been conducted. At this point, as a preceding study, this study will be able to provide theoretical grounds and meaningful insights to future studies.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.724-733
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• 2017

Accidents caused by upset condition leads to fatal damage to both manned and unmanned aircraft. This paper deals with real-time detection of these aircraft upset situations to prevent further severe situations. Firstly, the difference between sensor measurement and predicted measurement from Extended Kalman filter is monitored to determine whether a target aircraft goes into an upset condition or not. In addition, repeating the time update stage of the Extended Kalman filter for a specific length of time can enable future upset situation prediction. The results of aforementioned both the approaches will build a bridge to upset prevention for future generation of manned/unmanned aircraft.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.557-560
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• 2020

최근, 광소자에서 공간 변조되는 wavefront profile 특성을 광소자의 표면 단차 변화 없이 단일 두께 박막 상에서 자유로이 구현할 수 있는 기하위상 홀로그램 (geometric phase hologram) 기반의 optical component에 대한 관심이 증대되고 있다. 특히 이를 이용해 제작된 기하위상 렌즈 (geometric phase lens)는 dynamic phase의 공간적 차이에 의해 구현되던 기존 bulk optics 기반의 lens 대비 초박형으로 제작이 가능한 파장 선택적 flat optics 기술로써, 다초점 및 경량화를 요구하는 차세대 디스플레이 기술 (augmented reality 또는 AR, mixed reality 또는 MR) 및 광파변조 및 제어를 요구하는 홀로그래픽 카메라 분야에 대한 응용처로 많은 주목을 받고 있다. 이에 본 논문에서는 해당 기하 위상렌즈에 대한 원리 및 이에 따른 개발이슈 및 해결법에 대해 연구 하였으며, 이에 대한 응용처로 기하위상 렌즈의 편광에 따른 이중초점특성을 이용해, 기존 단일 초점 형성이 가능한 AR기기 대비, 다초점 형성이 가능한 switchable dual-depth 3D AR device를 compact한 모듈과 함께 구현하였다. 또한, 기하위상렌즈의 광파 변조 및 분리특성을 이용한 기하위상 렌즈기반의 자가간섭 홀로그래픽 시스템(GP-self-interference incoherent digital holographic, GP-SIDH)에 편광 이미지센서 적용과 함께 맞춤형 설계/제작된 기하 위상렌즈를 적용함으로써, 기존 GP-SIDH 시스템대비 안정적으로 실시간 복소 홀로그램 획득이 가능한 실시간 공간영상정보 획득용 GP-SIDH을 동영상 프레임으로 구현하였다.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.472-480
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• 2008

This study was conducted to evaluate the influence of the C-factor on the bond strength of a 6th generation self-etching system by measuring the microtensile bond strength of four types of restorations classified by different C-factors with an identical depth of dentin. Eighty human molars were divided into four experimental groups, each of which had a C-factor of 0.25, 2, 3 or 4. Each group was then further divided into four subgroups based on the adhesive and composite resin used. The adhesives used for this study were AQ Bond Plus (Sun Medical, Japan) and XenoIII (DENTSPLY, Germany). And composite resins used were fantasists (Sun Medical, Japan) and Ceram-X mono (DENTSPLY, Germany). The results were then analyzed using one-way ANOVA, a Tukey's test, and a Pearson's correlation test and were as follows. 1. There was no significant difference among C-factor groups with the exception of groups of Xeno III and Ceram-X mono (p<0.05). 2. There was no significant difference between any of the adhesives and composite resins in groups with C-factor 0.25, 2 and 4. 3. There was no correlation between the change in C-factor and microtensile bond strength in the Fantasista groups. It was concluded that the C-factor of cavities does not have a significant effect on the microtensile bond strength of the restorations when cavities of the same depth of dentin are restored using composite resin in conjunction with the 6th generation self-etching system.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.101-110
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• 2015

Parameters of mating system and pollen flow of a Pinus densiflora population in Buan, South Korea, were estimated using seven nuclear microsatellite markers. The expected heterozygosity ($H_e$) was 0.614 in mother trees and 0.624 in seeds. Fixation index (F) was 0.018 and 0.087 in each generation. There was no significant genetic difference between the generations (P > 0.05). From MLTR, the outcrossing rate ($t_m$), the biparental inbreeding ($t_m-t_s$), and the correlation of paternity ($r_p$) were 0.967, 0.057, and 0.012, respectively. tm was larger but $t_m-t_s$ and $r_p$ were smaller than those of allozyme markers in Pinus densiflora. These values were similar to those of microsatellite markers in other pine species. The optimal pollen dispersal model from TwoGener was the normal dispersal model with the effective density of 220 trees/ha and its level of genetic differentiation in pollen pool structure (${\Phi}_{ft}$) was 0.021. The average radial distance of pollen flow (${\delta}$) was calculated as 11.42 m, but no correlation between the pairwise-${\Phi}_{ft}$ and the geographical distance among mother trees was at Mantel test (r = -0.141, P > 0.05). Although the effective pollen dispersal in the population seems to be restricted, the amount of genetic variation might be maintained in each generation without a loss of genetic diversity. It might be because the genetic diversity in pollen pool was high but the genetic difference between pollen donors was small under the complete random mating condition in the Pinus densiflora population in Buan.

• Korean Journal of Culture and Social Issue
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• v.28 no.2
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• pp.219-239
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• 2022

The study investigated the relationship between subjective socioeconomic status (SES) of 508 Korean adults and their perception of justice (distributive and procedural justice for self and general others), and verified whether there is a moderating effect of age (20s versus 30s and over). A self-report survey on SES and perception of justice was conducted. Then, using the SPSS 27 and PROCESS Macro 4.0 program, a correlation analysis looking into the relationship among the study variables was performed along with the ANOVAs comparing the mean differences of study across age-groups to support the group division criteria. Next, a moderation analysis was conducted. The main results of this study are as follows. First, the participants' SES showed a positive relationship with all sub-factors of justice perception and a negative relationship with age. Second, age had a inverse relationship on distributive justice for self and general others, and procedural justice for self, but a non significant relationship on procedural justice for general others. Third, when looking into the mean differences of the research variables according to age, the 20s had different characteristics compared to the 30s and over. In comparison, there were no significant differences within the 30s and over group. Fourth, the moderating effect of age in the relationship between subjective SES and perception of justice was positively significant in the case of distributive justice for self and procedural justice for general others. In the case of distributive justice for self, the positive slope of the graph in which subjective SES predicts distributive fairness for self was steeper in the 30s and older group compared to the 20s. Regarding the procedural justice for general others, subjective SES was not a significant predictor in the 20s group. However, SES positively predicted procedural justice in the 30s and older group. This study is meaningful since it suggested age differences in subjective SES and perceptions of justice by revealing the different relationship patterns of subjective SES and perception of justice according to age.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.257-266
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• 2005

Background : The study of pneumonia among young men living in a group is rare. prospective study was conducted to determine the etiology, and compare the effects of macrolide and second-generation cephalosporin on the treatment of pneumonia among combat policemen. Patients and Methods : From January 2003 to April 2004, Fifty-two patients with pneumonia were treated with either azithromycin(n=25) or cefuroxime(n=27). In order to determine the cause of the pneumonia, culture studies and serologic tests for antibodies to Mycoplasma pneumoniae and Chlamydia pneumoniae were carried out. During the two weeks of medication, the Chest X-rays, blood tests and culture studies(if necessary) were followed weekly. A serologic study was followed at the end of the second week. Results : The main pathogens for pneumonia among combat policemen were Mycoplasma pneumoniae(50.0%), Chlamydia pneumoniae(10.8%), and Streptococcus pneumoniae(3.8%). The treatment was successful in most cases(51/52 cases, 98.1%). The effects of azithromycin and cefuroxime were similar (96.0% vs 100%, p>0.05). In one patient who had taken azithromycin, the clinical and radiological findings did not improved until intravenous second generation ce phalosporin had been infused. Conclusion : Atypical pathogens were the main causes of the pneumonia in the combat policemen, and the effects of macrolide and second generation cephalosporin for pneumonia were similar. However, further studies will be needed to determine if single therapy with macrolide is possible.

• Korean Journal of Culture and Social Issue
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• v.12 no.1
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• pp.161-195
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• 2006

The purpose of this study is to examine factors influencing quality of life for individuals in the family, school or workplace, leisure settings, and Korean society using the indigenous psychological analysis. A total of 3,406 participants, consisting of 1,331 elementary, middle, high school students and 2,075 parents and teacher, completed an open-ended questionnaire developed by Kim and Park (2004b). The respondents reported the factors that influence quality of life in Korean society as follows: Economic condition, collective effort, leisure and cultural life, harmonious interpersonal relationships, effective government policy, and educational attainment. The factors that reduce quality of life in Korean society are as follows: Economic uncertainty, political instability, lack of citizenry, ingroup favoritism, corruption, lack of facilities for leisure and social life, and overemphasis on educational achievement. Second, the factors that influence quality of life in the family are as follows: Harmonious family relations and financial security. For students relationship with friends and academic achievement are reported as important factors influencing quality of life at school. For adults, harmonious interpersonal relationship, financial factors and occupational achievement are reported as important factors influencing quality of life at the workplace. For leisure and social leisure life, financial security, leisure time and interpersonal relationships are reported as important factors influencing quality of life. Third, as for generational differences, students reported political instability and adults reported economic uncertainty as the most important factor reducing quality of life in Korean society. For family life, students reported conflicts among family members and adults reported financial constraints as the most important factor reducing quality of life. For leisure and social life, students reported lack of leisure time and adults reported financial constraints as the most important factor reducing quality of life. Fourth, for students the following characteristics were associated with higher quality of life: Higher socio-economic status of the family, younger, and higher academic achievement. For adults, the following characteristics were associated with higher quality of life: Higher socio-economic status of the family and greater achievement their social life. Implications of these results on the quality of life in Korea, focusing on human relationship, financial factors, self-regulation and educational achievement are discussed.

• Journal of Life Science
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• v.33 no.7
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• pp.565-573
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• 2023

In light of the complex interactions between the host animal and its resident gut microbiomes, studies of these microbial communities as a means to improve cattle production are important. This study was conducted to analyze the intestinal microorganisms of Holstein (HT) and Jersey (JS), raised in Korea and to clarify the differences in microbial structures according to cattle species through next-generation sequencing. The alpha-diversity analysis revealed that most species richness and diversity indices were significantly higher in JS than in HT whereas phylogenetic diversity, which is the sum of taxonomic distances, is not significant. Microbial composition analysis showed that the intestinal microbial community structure of the two groups differed. In the both groups, a significant correlation was observed among the distribution of several microbes at the family level. In particular, a highly significant correlation (p<0.0001) among a variety of microbial distributions was found in JS. Beta-diversity analyis was to performed to statistically verify whether a difference exists in the intestinal microbial community structure of the two groups. Principal coordinate analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering analysis showed separation between the HT and JS clusters. Meanwhile, permutational multivariate analysis of variance (PERMANOVA) revealed that their microbial structures are significantly different (p<0.0001). LEfSe biomarker analysis was performed to discover the differenc microbial features between the two groups. We found that several microbes, such as Firmicutes, Bacilli, Moraxellaceae and Pseudomonadales account for most of the difference in intestinal microbial community structure between the two groups.

• Journal of agricultural medicine and community health
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• v.35 no.4
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• pp.370-382
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• 2010

Objectives: The purpose of this study was to investigate the level of health promoting behaviors and the significant factors in rural elderly(young-old vs old-old). Methods: The data was collected using structured questionnaires from June 22th to Sep. 18th, 2009. A total of 556 elderly aged 65 years or over were selected from 14 rural districts in C province, South Korea. Age was divided into two groups as below 65-74 and 75 or older. A structured questionnaire was used to obtain information on the demographic characteristics, their perceived health status, the difficulty of activities of daily living, quality of life, self-efficacy and health promoting behaviors. The health promoting behaviors included nutrition, stress management, interpersonal support, exercise, health responsibility and self-actualization. The scores for health promoting behaviors were used mean and standard deviation. The data was analyzed using SPSS Win 12.0. Results: Of the 556 subjects, we found that the young-old(65-74 aged) were 359 and the old-old elderly(over 75 aged) were 197. We found that the level of health promoting behavior was higher for young-old ($2.75{\pm}0.374$) compared to old-old elderly people ($2.67{\pm}0.399$). In multiple linear regression, quality of life, self-efficacy, living with spouse, and number of generation living together for the young-old, and quality of life for old-old elderly were significantly associated with health promoting behaviors. Conclusions: The study findings indicate that there are age differences in associated factor of health promoting behaviors. Therefore our findings may provide useful assistance in developing effective intervention programs to improve health promoting behavior of the elderly in rural areas according to their age differences.