• The Journal of the Petrological Society of Korea
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• v.21 no.1
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• pp.13-30
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• 2012

Phlogopite and kaersutite, showing distinctively different textural characteristics compared to the common phenocrysts, are observed in alkali basalt from Jeju Island. They occur as large crystals (2-10 mm) in host basalts, whereas fine-grained phlogopite and kaersutite occur in ultramafic mantle xenoliths and mafic gabbroic xenoliths, respectively, as an interstitial and microvein phases, or in corona textures (<1 mm). This textural characteristics of fine-grained grains clearly indicates secondary in origin. Phlogopite contains high $TiO_2$(4.1-6.9 wt%) and F(2.8-4.6 wt%) and relatively high mg#[=100Mg/(Mg+$Fe^t$) in mols, where $Fe^t$ is total iron](88-80), whereas kaersutite has high $TiO_2$(5.6-6.11 wt%) and much lower mg#s(68-64). Our textural observations and the geochemical character of these hydrous minerals suggest that they were unrelated to each other and mica formation happened early in the upper mantle before the mantle xenoliths had been trapped. In contrast, kaersutite formation has happened later, probably during the late stage of crystallization as intracrustal processes. The presence of phlogopite and kaersutitic amphibole is a direct evidence for K-, Ti-, F- and $H_2O$-bearing fluid/melt percolation in the lithosphere beneath Jeju Island, indicating that they are product of interaction between host rock/peridotite/fluid-melt. Thus, the upper mantle/lower crust beneath Jeju Island are metasomatized to various extents, characterized by a change in major metasomatic hydrous minerals from phlogopite to amphibole with decreasing depth.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.425-431
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• 2020

When a radiation generating device is installed in an export container due to COVID-19, the purpose of this study was to measure the space dose in the radiation room and to study the effectiveness of the shielding wall in the laboratory. Air dose measurement method was set behind the X-ray tube, 50 cm, 100 cm, 200 cm, and measured 12 locations. The dose values before and after the use of the movable radiation shielding wall were compared by measuring 3 locations behind the X-ray tube using the movable radiation shielding wall. The measured values were 50 cm on the left behind the X-ray tube: 1.446 μSv, behind the X-ray tube: 0.545 μSv, and 50 cm on the right behind the X-ray tube: 1.466 μSv. Measurements behind the radiation barrier were 0.190 μSv, 0.204 μSv, and 0.191 μSv. As a result of performing the corresponding sample t test of the average value according to the use of movable barrier walls, p <0.001 was found. As a result of the actual measurement, the medical exposure of the examiner due to the shielding wall in the laboratory decreased to 82.3%. In order to reduce occupational exposure in screening radiological laboratories, it is recommended that sufficient separation from radiation sources and the use of shielding walls are recommended.

• Journal of Convergence for Information Technology
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• v.10 no.8
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• pp.77-86
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• 2020

The study aims to analyze the compliance and non-compliance of the Korean health authorities regarding WHO's mask use recommendations following the spread of Covid-19, and to suggest the limitations and implications of the recommendations in the prevention of epidemics by deriving the causes of non-compliance with the results of alternative options. To this end, documents related to masks at home and abroad are reviewed, and WHO's mask recommendations and the Korean health authorities' mask guidelines are targeted for analysis. The analysis results are as follows. First, Korea's health authorities have basically accepted and applied WHO's "limited mask user perspective" in two recommendations. Second, Korea's health authorities have implemented differently from WHO mask recommendations due to the lack of supply and demand of masks. Third, Korea's health authorities were able to succeed in the initial prevention of Corona 19 based on the stabilization of the mask supply. Fourth, in the WHO mask recommendations, mask user restriction resulted in partial errors as a recommendation. The implication derived from the analysis is that even international recommendations based on medical evidence need to be allowed to follow autonomous guidelines according to the country's quarantine situation and competence, rather than strict adherence to international rules, in the infectious disease pandemic situation.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.65-74
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• 1993

A miniature size electrostatic induction motor has been fabricated and studied with emphasis on the role of the surface resistivity, the relative dielectric constant and the charge relaxation time constant of the rotor surface materials and the rotor liner materials, which, however, control the surface charge induction and relaxation on the rotor material surface and the field intensity between the rotor and the stator of the motor. It is found that the surface resistivity and/or the relative dielectric constant, and the charge relaxation time constant of the rotor surface material enfluenced significantly to motor speed controlled by the surface charge induction and relaxation on the rotor surface depending on the applied voltage and/or frequency changing. The resistivity of the rotor liner material is also found to be effected to the motor speed greatly by control of the field intensity between the rotor and the stator and of the surface charge distribution of the induced charge on the rotor. As a result, a maximum no load rotor speed of the motor tested was about 5500 rpm at the applied voltage of 4.5 kV and the frequency of 220 Hz for the case of the rotor surface material of $BaTiO_{3}$ 80% in the resin binder layered on the copper-foil rotor liner material.

• Journal of Christian Education in Korea
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• v.67
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• pp.229-265
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• 2021

The purpose of this study is to suggest educational directions by exploring the stories of changes and expectations experienced by Christian children during the COVID-19 pandemic. For this purpose, nine third- to fourth-grade elementary school children attending the church, were interviewed about their changes and expectations regarding COVID-19. The results identified five areas of experience: daily life changes, school life changes, interpersonal relationship changes, religious life changes, and emotional changes during the COVID-19 period. Daily changes included infection prevention, missing play, leisurely routine, and lethargy. Changes in school life included loss of face-to-face classes and various rule requirements. Interpersonal relationship changes included the difficulties in forming relationships with friends, teachers, parents, and siblings, and religious life changes included loss of face-to-face worship and the restoration of family worship. Various negative emotions were expressed. Analysis of the participants' expectations showed in daily life they wanted to travel and play, return to pre-corona school life, return to face-to-face worship, restore retreats, and develop fun programs as religious life expectations. Based on these children's experiences and wishes, the study suggests that educators need to recognize children's efforts during the COVID-19 period, read their hurt feelings, and develop church programs that include communication, community, and fun elements.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.372-390
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• 2021

The objective of this study is to understand the current status of damage to Korean musical caused by the COVID-19, and also to seek for the coping measures and development direction in the post-Corona era. Thus, to understand the current status of damage, this study mainly researched the contents of NAVER TV musical performance transmitted for three years from March 2018 to February 2021 for analyzing the online performance and performance statistical data of Performing Arts Box Office Information System. As a result, this study could find a hypothesis and grounds to simultaneously verify and draw the positive and negative sides, pessimistic implications, and optimistic possibility. First, the performing arts would be multilaterally expanded after being divided into offline performance and online performance. Second, the utilization of online performance could narrow the gap(polarization) between capital area and non-capital area. Third, it is urgently needed to develop a win-win model for the establishment of a new musical market. Fourth, the performers' copyrights should be fairly protected. Fifth, the visualization requires the Korean-style support foundation and talent equipped with convergent thinking and knowledge. In such temporal changes from offline performance to online performance, there should be more sophisticated qualitative and quantitative growth in musical market.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.247-254
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• 2021

As COVID-19 spread, non-face-to-face activities were required, and the use of service robots is gradually increasing. This paper analyzed the relationship between the increasing trend of service robots before and after COVID-19 through keyword search containing the keyword 'service robot AND non-face-to-face' over the past three years (2018.10-20219) using BigKines, a news big data analysis system. As a result, there were 0 cases in the first period (2018.10~2019.9), 52 cases in the second period (2019.10~2020.9) and 112 cases in the third period (2020.10~2021.9), an increase of 115% compared to the second period. The keywords commonly mentioned in the analysis of related words in the second and third periods were COVID-19, AI, the Ministry of Trade, Industry, and Energy, and LG Electronics, and the weight of COVID-19 was the largest, confirming that the analysis keyword. Due to the spread of Corona 19, non-face-to-face is required, and with the development of information and communication technology, the field of application of service robots is rapidly increasing. Accordingly, for the commercialization of service robots that will lead the non-face-to-face economy, there is an urgent need to nurture human resources that require standardization and expertise in safety and performance fields.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.195-205
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• 2021

As Coronavirus disease 2019 (COVID-19) became a pandemic, most nursing departments in Korea implemented online non-face-to-face practices rather than the existing practice method. This study was a qualitative study that analyzed the reflection diaries written by participants to understand what they experienced in the online non-face-to-face adult nursing practice process. The online non-face-to-face adult nursing practice was 90 hours for two credits and nine hours per day for a total of 10 days. This online practice consisted of computer-based simulation practice, computer-based nursing skills practice, video and educational material production, real-time online quiz, online lecture video, and discussion. As a result of analyzing the reflection diary, six categories, 13 subcategories, and 33 codes were derived. The six categories were 'Experience of various situations', 'Experience of new study', 'Fulfillment for the clinical practice', 'Building relations with professors', 'Fear of being a pre-nurse', and 'Ambivalence for the non-face-to-face practice'. These results are significant in that in the post-corona era, adult nursing practice was conducted as a non-face-to-face practice rather than a clinical practice institution, and various educational methods were operated. This study is expected to provide important basic data for the development and operation of non-face-to-face adult nursing practice.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.21-35
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• 2020

Due to the coronavirus pandemic and diplomatic disputes, governments are actively developing a policy to revitalize·reshore manufacturing and to diversify international cooperations. In order to develop such a policy, it is very important to compare and analyze domestic·international geospatial information. Over the decade, the US·EC governments have conducted a series of national researches to build data-based tools that can monitor·analyze regional geospatial information driven by government R&D investments. In the case of the EC system, it can compare geospatial information in domestic and international(including Korea) regions. Compared to US·EC cases, Korean examples of national researches with available data analplatform need future improvements. Current study is investigating an automated analysis methodologies using "National Institute of Science and Technology Information (NTIS)" DB, which was national security data until recently. Research on data-mining regional geospatial information can contribute to support policy fields that need to discover new issues in response to unexpected social problems such as recently faced corona and trade disputes.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.85-99
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• 2021

Graphene, called the "dream material" is drawing attention as a groundbreaking new material that will lead the era of the 4th Industrial Revolution. Graphene has high strength, excellent electrical and thermal conductivity, excellent optical permeability, and excellent gas barrier properties. In this paper, as the South Korean government recently announced Green New Deal and Digital New Deal policy, we analyze graphene technology, which is also attracting attention for its application to Corona 19 biosensor, to understand its national R&D trend and knowledge structure, and to explore the possibility of its application. Firstly, 4,054 cases of national R&D project information for the last 10 years are collected from the National Science & Technology Information Service(NTIS) to analyze the trend of graphene-related R&D. Besides, projects classified as green technology are analyzed concerning the government's Green New Deal policy. Secondly, text mining analysis is conducted by collecting 500 recent graphene-related articles from e-newspapers. According to the analysis, the field with the largest number of projects was found to be high-efficiency secondary battery technology, and the proportion of total research funds was also the highest. It is expected that South Korea will lead the development of graphene technology in the future to become a world leader in diverse industries including electric vehicles, cellular phone batteries, next-generation semiconductors, 5G, and biosensors.