• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.119-126
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• 2023

Today, in order to improve fuel efficiency and dynamic behavior of automobiles, an era of light weight and simplification of automobile parts is being formed. In order to simplify and design and manufacture the shape of the product, various components are integrated. For example, in order to commercialize three products into one product, product processing is occurring to a very narrow area. In the case of existing parts, precision die casting or casting production is used for processing convenience, and the multi-piece method requires a lot of processes and reduces the precision and strength of the parts. It is very advantageous to manufacture integrally to simplify the processing air and secure the strength of the parts, but if a deep and narrow pocket part needs to be processed, it cannot be processed with the equipment's own spindle. To solve a problem, research on cutting processing is being actively conducted, and multi-axis composite processing technology not only solves this problem. It has many advantages, such as being able to cut into composite shapes that have been difficult to flexibly cut through various processes with one machine tool so far. However, the reality is that expensive equipment increases manufacturing costs and lacks engineers who can operate the machine. In the five-axis cutting processing machine, when producing products with deep and narrow sections, the cycle time increases in product production due to the indirectness of tools, and many problems occur in processing. Therefore, dedicated machine tools and multi-axis composite machines should be used. Alternatively, an angle spindle may be used as a special tool capable of multi-axis composite machining of five or more axes in a three-axis machining center. Various and continuous studies are needed in areas such as processing vibration absorption, low heat generation and operational stability, excellent dimensional stability, and strength securing by using the angle spindle.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.5
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• pp.13-29
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• 2023

Urban parks are social infrastructure supporting citizens' health, quality of life, and community formation. As the proportion of urban parks that have been established for more than 20 years is increasing, the need for refurbishment to improve the physical space environment and enhance the functions of aging urban parks is increasing. Since the government's refurbishment of aging urban parks has limitations in securing financial resources and promoting attractiveness, they must be promoted through public-private partnerships. Japan, which suffered from the problem of aging urban parks, has successfully promoted several park refurbishment projects by introducing the Park-PFI through the revision of the 「Urban Park Act」 in 2017. This study examines and analyzes the characteristics of the Japan Park-PFI as an alternative to improving the quality of aging domestic urban park services through public-private partnerships and the validity of the aging urban park refurbishment projects through Park-PFI. The main findings are as follows. First, it is necessary to start discussions on introducing Japan's Park-PFI according to the domestic conditions as a means of public-private partnership to improve the service quality and diversify the functions of aging urban parks. In order to introduce Park-PFI social discussions and follow-up studies on the deterioration of urban parks. Must be conducted. The installation of private capital and profit facilities and improvements of related regulations, such as the 「Parks and Green Spaces Act」 and the 「Public Property Act」, is required. Second, it is judged that the Park-PFI project is a policy alternative that can enhance the benefits to citizens, local governments, and private operators under the premise that the need to refurbish aging urban parks is high and the location is suitable for promoting the project. As a result of a pilot application of the Park-PFI project to Seyeong Park, an aging urban park located in Bupyeong-gu, Incheon, it was analyzed to be profitable in terms of the profitability index (PI), net present value (FNPV), and internal rate of return (FIRR). It is considered possible to participate in the business sector. At the local government level, private capital is used to improve the physical space environment of aging urban parks, as well as the refurbishment of the urban parks by utilizing financial resources generated by returning a portion of the facility usage fees and profits (0.5% of annual sales) of private operators. It was found that management budgets could be secured.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.543-553
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• 2023

The current status of domestic a agalmatolite mines in South Korea was investigated with a view to establishing a stable supply of agalmatolite and managing its demand. Most mined agalmatolite deposits were formed through hydrothermal alteration of Mesozoic volcanic rocks. The physical characteristics of pyrophyllite, the main constituent mineral of agalmatolite, are as follows: specific gravity 2.65~2.90, hardness 1~2, density 1.60~1.80 g/cm³, refractoriness ≥29, and color white, gray, grayish white, grayish green, yellow, or yellowish green. Among the chemical components of domestic agalmatolite, SiO₂ and Al₂O₃ contents are respectively 58.2~67.2 and 23.1~28.8 wt.% for pyrophyllite, 49.2~72.6 and 16.5~31.0 wt.% for pyrophyllite + dickite, 45.1 and 23.3 wt.% for pyrophyllite + illite, 43.1~82.3 and 11.4~35.8 wt.% for illite, and 37.6~69.0 and 19.6~35.3 wt.% for dickite. Domestic agalmatolite mines are concentrated mainly in the southwest and southeast of the Korean Peninsula, with some occurring in the northeast. Twenty-one mines currently produce agalmatolite in South Korea, with reserves in the order of Jeonnam (45.6%) > Chungbuk (30.8%) > Gyeongnam (13.0%) > Gangwon (4.8%), and Gyeongbuk (4.8%). The top 10 agalmatolite-producing mines are in the order of the Central Resources Mine (37.9%) > Wando Mine (25.6%) > Naju Ceramic Mine (13.4%) > Cheongseok-Sajiwon Mine (5.4%) > Gyeongju Mine (5.0%) > Baekam Mine (5.0%) > Minkyung-Nohwado Mine (3.3%) > Bugok Mine (2.3%) > Jinhae Pylphin Mine (2.2%) > Bohae Mine. Agalmatolite has low thermal conductivity, thermal expansion, thermal deformation, and expansion coefficients, low bulk density, high heat and corrosion resistance, and high sterilization and insecticidal efficiency. Accordingly, it is used in fields such as refractory, ceramic, cement additive, sterilization, and insecticide manufacturing and in filling materials. Its scope of use is expanding to high-tech industries, such as water treatment ceramic membranes, diesel exhaust gas-reduction ceramic filters, glass fibers, and LCD panels.

• Korean Journal of Environment and Ecology
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• v.37 no.5
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• pp.367-391
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• 2023

This study was conducted for 10 years from 2012, which is a year before the forest road construction in Minjujisan, to 2022 to analyze annual changes in flora and vegetation before and after the forest road construction and to provide strategies for management. The plant communities in the research sites along the forest road showed the differentiation between slopes with Quercus mongolica community on the northwestern slope and Quercus variabilis and Larix kaempferi communities on the southwestern slope. A total of 212 taxa have increased for number 7 between before and after the construction from a total of 66 taxa (44 families, 59 genera, 51 species, 13 varieties, and 2 forma) in 2012 and 207 taxa (71 families, 153 genera, 176 species, 27 varieties, and 4 forma) in 2015 to 278 taxa (78 families, 172 genera, 242 species, 1 subspecies, 31 varieties, and 4 forma) in 2022. It is noteworthy that the vegetation cover and the introduction of new taxa had been expanded in the sites adjacent to the construction, which is likely caused by the significantly increased amount of light and the introduction of annual herbaceous and naturalized plants after the construction. The results of 10 years of current study reveal that the vegetation cover and the number of new taxa had rapidly increased in earlier years after the construction, slowly decreased later on, and finally formed a stable forest with the increase in the ratio of dominant species. The vegetation cover of the herbaceous layer immediately increased on the slopes along the forest road for a few years after the construction although it had continuously decreased while that of the shrub layer quickly increased. It was shown that on the hillslope the vegetation cover of tall- and low-tree layers increased whereas that of herbaceous and shrub layers rapidly decreased.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.5
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• pp.217-240
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• 2023

For a while, Functional cosmetics, Cosmeceutical cosmetics, and Derma cosmetics have gained trust and become popular due to the consumers' strong interest in ingredients & efficacy. It's remarkable that Clean or Vegan brands are growing fast because they are emphasizing on different values from the other cosmetic brands. It's needed to attempt to analyze the influence relationship between consumer lifestyle and social value in these changes, and to find out whether the consumption of vegan cosmetics is related to satisfying the need for self-expression in a social atmosphere where ESG is emphasized on. This study analyzed the effect of lifestyle types and self-expression needs on the purchase intention of vegan cosmetics by mediating social values for cosmetics consumers. Lifestyle types were classified into appearance-oriented, health-oriented, and fashion-oriented. For empirical analysis, 321 questionnaires collected from cosmetics consumers living across the country were used. SPSS v26.0 and PROCESS macro v4.2 were used to analyze based on a single mediating model as a single mediator. As a result of the analysis, first, lifestyle types and self-expression needs, excluding appearance-oriented types, were found to have a positive (+) effect on social values. Second, it was found that social value had a positive (+) significant effect on the purchase intention of vegan cosmetics. Third, appearance-oriented, health-oriented, trend-seeking lifestyle types and self-expression needs were all found to have a positive (+) effect on the purchase intention of vegan cosmetics. Fourth, social values were found to mediate lifestyle types, self-expression needs, and purchase intentions, except for appearance-oriented types. Appearance-oriented consumers do not directly affect social values but affect purchase intentions, suggesting that appearance-oriented consumers may not be significantly affected by product-related social values. In a comparison of the relative influence size using standardization coefficients, self-expression needs had the greatest impact on the purchase intention of vegan cosmetics when mediating social values, and health-oriented ones had the least impact. The academic implications of this study include contributing to consumer behavior research by providing insights, mediation mechanisms, and consideration of the niche consumer sector, and directing further research into the cosmetics industry beyond forming marketing strategies and sustainable business practices.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.251-261
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• 2007

The wind-wave interaction around the Kyung-gi Bay, Korea, was studied using the observed data from ocean buoy at DeuckJeuck-Do from Jan. to Dec., 2005, and from waverider data at KeuckYeulBee-Do on Mar. 19-26 and May 23-28, 2005. Wind-driven surface waves and wave-driven wind speed decrease were estimated from the ocean buoy data, and the characteristics of wave spectrum response were also investigated from the waverider data for the wave developing and calm stages of sea surface, including the time series of spectrum pattern change, frequency trend of the maximum energy level and spectrum slope for the equilibrium state range. The wind speed difference between before and after considering the wave effect was about $2ms^{-1}$ (wind stress ${\sim}0.1Nm^{-2}$) for the wind speed range $5-10ms^{-1}$ and about $3ms^{-1}$ (wind stress ${\sim}0.4Nm^{-2}$) for the wind speed range $10-15ms^{-1}$. Correlation coefficient between wind and wave height was increased from 0.71 to 0.75 after the wave effect considered on the observed wind speed. When surface waves were generated by wind, the initial waves were short waves about 4-5 sec in period and become in gradual longer period waves about 9-10 sec. For the developed wave, the frequency of maximum energy was showed a constant value taking 6-7 hours to reach at the state. The spectrum slope for the equilibrium state range varied with an amplitude in the initial stage of wave developing, however it finally became a constant value 4.11. Linear correlation between the frictional velocity and wave spectrum for each frequency showed a trend of higher correlation coefficient at the frequency of the maximum energy level. In average, the correlation coefficients were 0.80 and 0.82 for the frequencies 0.30 Hz and 0.35 Hz, respectively.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.143-159
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• 2024

Natural aggregate is an essential resource for human activities, closely related to construction. The aggregate demand has been increasing annually, and due to the nature of the resource, it is difficult to procure from distant locations. This study identifies the distribution and characteristics of aggregate-bearing areas as part of a municipal-level aggregate resource survey conducted in Nonsan City, Korea, in 2023. Nonsan City is located approximately 35 km straight distance from the Geum River estuary and lies at the passageway of the main stream of the Geum River. The topography of Nonsan City features eastern mountainous areas and western plains, creating an east-high-west-low geomorphic setting, with 33 streams distributed across the city, including tributaries of the Geum River like Nonsan Stream, Noseong Stream, and Ganggyeong Stream. All streams originate from the highlands in the north and east, converge with Nonsan Stream, and then join the west bank of the main stream of the Geum River at the western boundary of Nonsan City. Drilling core results show shallow depths in the highlands to the north and east, deepening towards the west, reaching a maximum depth of 25 m near the main stream of the Geum River. The total reserve of land aggregates is calculated to be 246,789,000 m³, with a developable amount of 172,750,000 m³. The total reserve of river aggregates is 5,236,000 m³, with a developable amount of 3,765,000 m³. The distribution of aggregates varies according to the geomorphic, geologic, and development pattern of the river system. Reserves are scarce in mountainous areas but are abundant in regions with rivers and wide alluvial plains, although reserves appear at depths greater than 4m. The distribution of aggregate resources in Nonsan City is influenced by stream activities and sea level changes, with the tidal range of the Yellow Sea acting as an unfavorable condition for the preservation of aggregate resources.

• Journal of Life Science
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• v.34 no.7
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• pp.465-475
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• 2024

Lactiplantibacillus plantarum K9 is a probiotic strain that can be utilized from various bioactive substances isolated from Protaetia brevitarsis seulensis larvae. In this study, a genetic analysis of L. plantarum K9 revealed the existence of a bacterial chromosome and three plasmids. The glycolysis pathway and pentose phosphate pathway were examined for their normal functioning via an analysis of the core metabolic pathways of L. plantarum K9. Since the key enzymes, fluctose-1,6-bisphospatase (EC: 3.1.3.11) and 6-phosphogluconate dehydratase (EC: 4.2.1.12)/2-keto-deoxy-6-phosphogluconate (KDPG) aldolase (EC: 4.2.1.55), of gluconeogenesis and the ED pathway were not identified from the L. plantarum K9 genome, we suggest that gluconeogenesis and the ED pathway are not performed in L. plantarum K9. Additionally, while some enzymes, related to fumarate and malate biosyntheses, involved in the TCA cycle were identified from L. plantarum K9, the enzymes associated with the remaining TCA cycle were absent, indicating that the TCA cycle cannot proceed. Meanwhile, based on our findings, we propose that the oxidative electron transport system performs class IIB-type (bd-type) electron transfer. In summary, we assert that L. plantarum K9 performs homolactic fermentation, executes gluconeogenesis and the pentose phosphate pathway, and carries out energy metabolism through the class IIB-type oxidative electron transport system. Therefore, we suggest that L. plantarum K9 has relatively high lactic acid production, and that it has excellent antibacterial activity, as a result, compared to other lactic acid bacterial strains. Moreover, we speculate that L. plantarum K9 has an oxidative electron transport capability, indicating that it is highly resistant to oxygen and suggesting that it has fine cultivation characteristics, which collectively make it highly suitable for use as a probiotic.

• Food Science and Preservation
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• v.30 no.6
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• pp.1056-1071
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• 2023

This study aimed to investigate the quality and microbial population changes for 90 days under two fermentation conditions, outdoors and indoors (35℃), with starters (single or mixed) in soybean paste. Bacillus velezensis NY12-2 (S1), Debaryomyces hansenii D5-P5 (S2), Enterococcus faecium N78-11 (S3), and their mixtures (M) were used for the makjang fermentation. The content of amino-type nitrogen among the makjang samples was highly shown in the indoors, followed by M, S3, and S2. The glutamic and aspartic acid contents in the M sample fermented in the indoors showed the highest values of 867.42±77.27 and 243.20±15.79 mg/g, respectively. By the electronic tongue analysis, the M sample fermented in the indoors exhibited lower saltiness and higher umami than the others. Consequently, we expect that using mixed strains, such as Bacillus, Debaryomyces, and Enterococcus, under constant conditions showed potential to the quality improvement of soy products.

• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.129-139
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• 2023

Background: The elderly population aged 65 or older in Korea is expected to continue to increase to 18.4% in 2023, and to enter a super-aged society at 20.6% in 2025. In clinical practice, the elderly discrimination of dental hygienists may experience difficulties during dental hygiene treatment due to an increase in the number of elderly patients due to aging, which can lead to maladjustment to work and turnover, so education on the understanding of the elderly is essential for students in the Department of Dentistry, who are prospective dental hygienists. Accordingly, a study was conducted to prepare for a super-aged society by studying the relationship between elderly discrimination and the knowledge and attitudes of the elderly, and to change the curriculum of universities and develop programs related to the elderly. Method: 204 students enrolled in the Department of Dentistry in D area were analyzed using the SPSS/WIN 25.0 program. The subject's geriatric discrimination, knowledge about the elderly, and attitude toward the elderly were calculated as the mean and standard deviation. T-test and one-way ANOVA were performed to verify the difference in geriatric discrimination according to the general characteristics of the subject, with a Scheffe' test applied for post-hoc analysis. Correlation analysis was conducted on the subject's geriatric discrimination, knowledge about the elderly, and attitudes toward the elderly. Results: Geriatrics scored 2.03±0.36 out of 4. Knowledge about the elderly was categorized as follows: physical domain 0.57±0.15; social domain 0.36±0.17; and psychological domain 0.35±0.20. The attitude toward the elderly was 3.86±0.27. Knowledge of the elderly averaged 11.27±3.30 points out of 25. The question with the highest percentage of correct answers to knowledge about the elderly was 'physical strength tends to decrease with age', which was 93.1%. The attitude toward the elderly according to the general characteristics of the study subjects showed significant differences in gender (p=0.040), age (p=0.026), and life experience with grandparents (p=0.001). The elderly discrimination of the study subjects showed a negative correlation in both attitude and knowledge toward the elderly, and among the elderly discrimination, there was a high positive correlation with regard to emotional avoidance (r=.892, p<0.001). Conclusion: College students are the leading players in caring for the elderly and are directly affected by aging social problems. Therefore, it is considered necessary to apply various programs in the state, society, and educational institutions to avoid negative prejudices that lead to positive thinking and discrimination against the elderly.