• Economic and Environmental Geology
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• v.54 no.1
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• pp.35-48
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• 2021

The Gumi basin, situated in the mid-southeastern Yeongnam Massif, has the Cretaceous stratigraphy that is divided into Gumi Formation, andesitic rocks (Yeongamsan Tuff, Busangni Andesite), rhyolitic rocks (Obongni Tuff, Doseongul Rhyolite, Geumosan Tuff) and Intrusives (ring dikes, other dikes) in ascending order. The Geumosan Tuff is composed mostly of many ash-flow tuffs which are associated with Geumosan caldera along with the ring dikes. The caldera is outlined by ring faults and dikes and has about 3.5 × 5.6 km in diameters. The intracaldera volcanics show a downsag structure that is dipped inward in their flow and welding foliations. The caldera block represent an asymmetric subsidence, which drops 350 m in the northern margin and 600 m in the southern one. Based on these data, the Geumosan caldera is geometrically classified as an asymmetric piston subsidence caldera that suggests a single caldera cycle. The caldera reflects the piston subsidence of the caldera block bounded by the outward-dipping ring faults following a voluminous eruption of magma from the chamber. The downsag in the caldera block refers to the downsagging during the initial subsidence at the same time as the full development of the bound fault. In the ring fissures following the sagging, magma was injected due to the overpressure of magma chamber caused by subsidence.

• The Journal of Industrial Distribution & Business
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• v.12 no.1
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• pp.47-62
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• 2021

Purpose: Our purpose in this study was to examine the strategies for the development of watermelon industry using unstructured big data analysis. That is, this study was to look the change of issues and consumer's perception about watermelon using big data and social network analysis and to investigate ways to strengthen the competitiveness of watermelon industry based on that. Methodology: For this purpose, the data was collected from Naver (blog, news) and Daum (blog, news) by TEXTOM 4.5 and the analysis period was set from 2015 to 2016 and from 2017-2018 and from 2019-2020 in order to understand change of issues and consumer's perception about watermelon or watermelon industry. For the data analysis, TEXTOM 4.5 was used to conduct key word frequency analysis, word cloud analysis and extraction of metrics data. UCINET 6.0 and NetDraw function of UCINET 6.0 were utilized to find the connection structure of words and to visualize the network relations, and to make a cluster of words. Results: The keywords related to the watermelon extracted such as 'the stalk end of a watermelon', 'E-mart', 'Haman', 'Gochang', and 'Lotte Mart' (news: 015-2016), 'apple watermelon', 'Haman', 'E-mart', 'Gochang', and' Mudeungsan watermelon' (news: 2017-2018), 'E-mart', 'apple watermelon', 'household', 'chobok', and 'donation' (news: 2019-2020), 'watermelon salad', 'taste', 'the heat', 'baby', and 'effect' (blog: 2015-2016), 'taste', 'watermelon juice', 'method', 'watermelon salad', and 'baby' (blog: 2017-2018), 'taste', 'effect', 'watermelon juice', 'method', and 'apple watermelon' (blog: 2019-2020) and the results from frequency and TF-IDF analysis presented. And in CONCOR analysis, appeared as four types, respectively. Conclusions: Based on the results, the authors discussed the strategies and policies for boosting the watermelon industry and limitations of this study and future research directions. The results of this study will help prioritize strategies and policies for boosting the consumption of the watermelon and contribute to improving the competitiveness of watermelon industry in Korea. Also, it is expected that this study will be used as a very important basis for agricultural big data studies to be conducted in the future and this study will offer watermelon producers and policy-makers practical points helpful in crafting tailor-made marketing strategies.

• Environmental and Resource Economics Review
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• v.30 no.1
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• pp.129-167
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• 2021

The emission trading system is an essential policy for reducing greenhouse gas emissions and converting low-carbon society. EU ETS is a good benchmark that is ahead of Korea's emission trading system in terms of operating period and design know-how. Therefore, this study focused on the key design elements of EU ETS phase 4 such as total emission allowances issued (Cap), free allocation method, carbon leakage list, market stability reserve, and innovation supporting system. In addition, we analyzed the impact of key design elements and their changes during EU ETS Phase 1 to 4 on the design and operation of Korea emission trading system in the future. First of all, the expected impact on the design of Korea emission trading system is to increase three demands: preparing benchmark renewal plans, establishing criteria for selecting free allocation industries that reflect domestic industrial structure and characteristics and introducing two-stage evaluations for free allocation industries, and preparing specific plan to support innovation and industries using allowance auction revenues. The next three impacts on the operation of Korea emission trading system are the increased needs for objective and in-depth impact assessment of plan and amendments, provision of system stability and response opportunities by quickly confirming plan and amendments prior to the implementation, and coordination of the emission trading system governance and stakeholder participation encouragement.

• Journal of Environmental Impact Assessment
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• v.30 no.4
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• pp.203-214
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• 2021

Assessment of benthic quality status was implemented along the subtidal areas of Jindo and Jejudo to understand faunal structure of polychaete assemblages and ecological quality of the benthic environment. Sediment analysis was characterized by well sorted of both mud and sand in Jindo, and a little higher sand in Jejudo instead. A total of 68 polychaete species were found at 14 sampling stations with a mean density of 231 inds./m², and 61 species, 167 inds./m² and 62 species, 295 inds./m² in Jindo areas and Jejudo areas. Dominant species found in Jindo areas were Heteromastus filiformis, Ampharete arctica, Prionospio sp., Sigambra tentaculata, Thelepus sp. and Amphicteis gunneri, Ampharete arctica, Prionospio sp., Spiochaetopterus costarum, Heteromastus filiformis in Jejudo. With a help of cluster analysis, it was found that the sampling stations showed distinctive pattern of the distribution pattern and benthic quality status in Jindo and Jejudo except sampling station numbers 5 and 6, respectively. AMBI analysis the results were 1.2-3.4, grade V benthic polychaetes did not appear. It was evident that both Jindo and Jejudo had different sedimentary characteristics as well as distribution pattern of polychaete assemblages.

• Particle and aerosol research
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• v.17 no.4
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• pp.125-132
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• 2021

Fresh PM_2.5 smokes emitted from combustion of four biomass materials (pellet, palm fruit fiber (PFF), PKS, and sawdust) in a laboratory-controlled environment were characterized using an attenuated total reflectance-fourier transform infrared (ATR-FTIR) technique. In smoke samples emitted from combustion of pellets, PFF and PKS, which is being used as boiler fuels for greenhouses in rural areas, the organic carbon/elemental carbon (OC/EC) ratios in PM_2.5 were very high (14.0-35.5), whereas in sawdust smoke samples they were significantly low (<4.0) due to the combustion method close to flaming combustion. ATR-FTIR analysis showed that OH(3400-3250 cm^-1), CH₃(2958-2840 cm^-1), CH₂(2910 cm^-1 and 2850 cm^-1), ketone(1726-1697 cm^-1), C=C(1607-1606 cm^-1 and 1515-1514 cm^-1), lignin (1463-1462 cm^-1 and 1430-1428 cm^-1) and -NO₂(1360-1370 cm^-1) peaks were identified in all biomass burning (BB) smoke samples. However, additional peaks appeared depending on the type of biomass. Among the four types of biomass materials, an additional peak of the methylene group CH₃(2872-2870 cm^-1) appeared only in PFF and PKS smoke samples, and a peak of C=O(1685 cm^-1) was also confirmed. And in the case of PKS smoke samples, a peak of aromatic C=C(1593 cm^-1 and 1476 cm^-1) that did not appear in other BB samples was also observed. This indicates that the molecular structure of organic compounds emitted during BB differs depending on the type of biomass materials. The results of this study are expected to provide valuable information to more specifically reveal the effect of BB on PM_2.5 collected in the atmospheric environment.

• Korean Association of Arts Management
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• no.57
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• pp.59-84
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• 2021

This study examined the structure of YouTube video network and the factors for the diffusion of Chinese creator's videos through the case of famous Chinese creator Fengtimo. There is few interest to the diffusion of Chinese contents among Korean researchers, while they have been studied the consumption of Hallyu(Korean wave) contents overseas. Using the data that YouTube Data API offers, this study analysed the video network that the comments of which are same users with NodeXL tools and the regression model with JASP tools. The study found that there are three groups of the YouTube channels of that network. They are domestic official accounts of Fengtimo, foreign officail accounts of Fengtimo and individual creators' accounts. The official accounts share the videos of Fengtimo's songs and entertainment contents for the fans, where the individual creators share their own meme videos(UGC). The significant factors for the diffusion in the YouTube video network are comments, likes, out-degree, dislikes, in-degree and betweenness centrality. There are significant difference between official channel and indivisual groups on the views. And degree and betweenness centrality have mediating effect. It is necessary to conduct more research on that subject with many other cases if we want to get to know the generalized explanation.

• Health Policy and Management
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• v.32 no.4
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• pp.368-379
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• 2022

Background: This study aimed to establish a strategy to improve the poor working environment and working conditions among long-term healthcare workers in Korea. Methods: A total of 600 questionnaires with which long-term health care workers participated in the targeted base areas of each city and province nationwide were distributed directly and 525 responses were collected and 506 responses were analyzed. Surveys, on-site field visits, and in-depth interviews were also conducted to understand the working environment as well as conditions and establish a strategy for improving the working environment among long-term healthcare workers to understand the demands of working conditions and working conditions. Results: Korean long-term care workers firstly and mostly enumerated their risk factors for ill-health when lifting or moving elderly recipients directly by hand (69.9%), followed by increased physical workload with old beds, tools, and facilities (42.3%) in the workplaces, shortage of manpower (32%), and source of infection (30%). To improve the working environment as well as conditions, Korean long-term care workers considered improving low-wage structures, ergonomic improvements to solve excessive physical loads, and increasing various bonus payments as well as implementing the salary system, positive social awareness, and increasing resting time. Of 506 responses, 92.3% replied that the long-term care insurance system for the elderly should be developed to expand publicization at the national level. Conclusion: This study proposes to improve the low-wage structure of Korean long-term care workers, automation and improvement of facilities, equipment, and tools to eliminate excessive physical loads (beneficiary elderly lifting), and reduction of night labor.

• Journal of Periodontal and Implant Science
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• v.52 no.4
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• pp.338-350
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• 2022

Purpose: Various studies have investigated 3-dimensional (3D)-printed implants using Ti6Al-4V powder; however, multi-root 3D-printed implants have not been fully investigated. The purpose of this study was to explore the stability of multirooted 3D-printed implants with lattice and solid structures. The secondary outcomes were comparisons between the 2 types of 3D-printed implants in micro-computed tomographic and histological analyses. Methods: Lattice- and solid-type 3D-printed implants for the left and right mandibular third premolars in beagle dogs were fabricated. Four implants in each group were placed immediately following tooth extraction. Implant stability measurement and periapical X-rays were performed every 2 weeks for 12 weeks. Peri-implant bone volume/tissue volume (BV/TV) and bone mineral density (BMD) were measured by micro-computed tomography. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were measured in histomorphometric analyses. Results: All 4 lattice-type 3D-printed implants survived. Three solid-type 3D-printed implants were removed before the planned sacrifice date due to implant mobility. A slight, gradual increase in implant stability values from implant surgery to 4 weeks after surgery was observed in the lattice-type 3D-printed implants. The marginal bone change of the surviving solid-type 3D-printed implant was approximately 5 mm, whereas the value was approximately 2 mm in the lattice-type 3D-printed implants. BV/TV and BMD in the lattice type 3D-printed implants were similar to those in the surviving solid-type implant. However, BIC and BAFO were lower in the surviving solid-type 3D-printed implant than in the lattice-type 3D-printed implants. Conclusions: Within the limits of this preclinical study, 3D-printed implants of double-rooted teeth showed high primary stability. However, 3D-printed implants with interlocking structures such as lattices might provide high secondary stability and successful osseointegration.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.225-240
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• 2022

Gyeonggi-do comprises several types of areas, including urban, semi-urban, and rural areas. The availability of public transportation services varies depending on the area types, but the fare structure is based on a simple transfer rule, i.e., a transfer is free when completed within 30 minutes. As a result, users in non-urban areas with a poor frequency of public transportation services do not receive transfer discounts because most of the bus routes in these areas have a gap of more than 30 minutes between services. In terms of equality of opportunity, the transfer rule is being applied unfavorably and, as a result, equality of opportunity of the non-urban commuter is severely affected. Therefore, this study analyzed the user benefits mainly stemming from transfer fares using the smart card data of commuters using public transportation in Gyeonggi-do. An index called the beneficiary rate of the free transfer was developed and a scenario analysis was conducted based on the various levels of the rate. The results of this analysis proved that the users of public transportation services in non-urban areas in Gyeonggi-do can only receive transfer benefits by the extended time for free transfer and not by the implementation of a uniform policy irrespective of the type of area. The study also suggested an equitable fare transfer system and policy alternatives.

• Membrane Journal
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• v.33 no.4
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• pp.211-221
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• 2023

This study presents a comprehensive study on the synthesis and characterization of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C flexible electrodes for energy storage applications. The dual-functional PVI-PGMA copolymer exhibited excellent ionic conductivity, with the PVI-PGMA73/LiTFSI200 membrane electrolyte achieving the highest conductivity of 1.0 × 10^-3 S cm^-1. The electrochemical performance of the CxNy-C electrodes was systematically investigated, with C3N2-C demonstrating superior performance, achieving the highest specific capacitance of 958 F g^-1 and lowest charge transfer resistance (R_ct) due to its highly interconnected hybrid structure comprising nanowires and polyhedrons, along with binary Co/Ni oxides, which provided abundant redox-active sites and facilitated ion diffusion. The presence of a graphitic carbon shell further contributed to the enhanced electrochemical stability during charge-discharge cycles. These results highlight the potential of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C electrodes for advanced energy storage devices, such as supercapacitors and lithium-ion batteries, paving the way for further advancements in sustainable and high-performance energy storage technologies.