• Journal of the Korean Society of Food Culture
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• v.24 no.1
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• pp.77-83
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• 2009

This study was conducted to investigate the chemical composition and biological function of tea made from mountain-cultivated ginseng leaves. The antioxidant activities of tea made from mountain-cultivated ginseng leaves were determined by measuring their electron-donating ability based on their DPPH and nitrite-scavenging ability. The electron-donating abilities of tea made from mountain-cultivated ginseng leaves (500 and 1,000 ppm) as determined by DPPH assay were 45.6 and 85.1%, respectively. The nitrite scavenging ability of tea made from mountain-cultivated ginseng leaves (500 and 1,000 ppm) at pH 6.0 were 32.8 and 51.4%, respectively. Furthermore, the nitrite scavenging activity increased in a dose-dependent manner at all pH values. The effects of tea made from mountain-cultivated ginseng leaves on Male Sprague-Dawley rats were also evaluated. To accomplish this, the rats were divided into three groups (A: normal diet group, B: high fat diet group and C: high fat diet supplemented with tea made from mountain-cultivated ginseng leaves group). The anti-obesity effects of tea made from mountain-cultivated ginseng leaves were then evaluated. The serum total lipid, total cholesterol and triglyceride contents in C group were lower than those of B group; however, these differences were not statistically significant. The HDL-cholesterol content was significantly higher in the C group than in the other groups. Taken together the results of this study suggest that tea made from mountain-cultivated ginseng leaves possesses antioxidant activity and improves lipid metabolism.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.306-314
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• 2023

Stream sediments are an important component of water quality management because they are receptors of various pollutants such as heavy metals and organic matters emitted from upland sources and can be secondary pollution sources, adversely affecting water environment. To effectively manage the stream sediments, identification of primary sources of sediment contamination and source-associated control strategies will be required. We evaluated the performance of machine learning models in identifying primary sources of sediment contamination based on the physico-chemical properties of stream sediments. A total of 356 stream sediment data sets of 18 quality parameters including 10 heavy metal species(Cd, Cu, Pb, Ni, As, Zn, Cr, Hg, Li, and Al), 3 soil parameters(clay, silt, and sand fractions), and 5 water quality parameters(water content, loss on ignition, total organic carbon, total nitrogen, and total phosphorous) were collected near abandoned metal mines and industrial complexes across the four major river basins in Korea. Two machine learning algorithms, linear discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the sediments into four cases of different combinations of the sampling period and locations (i.e., mine in dry season, mine in wet season, industrial complex in dry season, and　industrial complex in wet season). Both models showed good performance in the classification, with SVM outperformed LDA; the accuracy values of LDA and SVM were 79.5% and 88.1%, respectively. An SVM ensemble model was used for multi-label classification of the multiple contamination sources inlcuding landuses in the upland areas within 1 km radius from the sampling sites. The results showed that the multi-label classifier was comparable performance with sinlgle-label SVM in classifying mines and industrial complexes, but was less accurate in classifying dominant land uses (50~60%). The poor performance of the multi-label SVM is likely due to the overfitting caused by small data sets compared to the complexity of the model. A larger data set might increase the performance of the machine learning models in identifying contamination sources.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.19-26
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• 2023

Hydrogen, a clean energy source free of COx emissions, is poised to replace fossil fuels, with its usage on the rise. Despite its high energy content per unit mass, hydrogen faces limitations in storage and transportation due to its low storage density and challenges in long-term storage. In contrast, ammonia offers a high storage capacity per unit volume and is relatively easy to liquefy, making it an attractive option for storing and transporting large volumes of hydrogen. While NH₃ decomposition is an endothermic reaction, achieving excellent low-temperature catalytic activity is essential for process efficiency and cost-effectiveness. The study examined the effects of different zeolite types (5A, NaY, ZSM5) on NH₃ decomposition activity, considering differences in pore structure, cations, and Si/Al-ratio. Notably, the 5A zeolite facilitated the high dispersion of Ni across the surface, inside pores, and within the structure. Its low Si/Al ratio contributed to abundant acidity, enhancing ammonia adsorption. Additionally, the presence of Na and Ca cations in the support created medium basic sites that improved N₂ desorption rates. As a result, among the prepared catalysts, the 15 wt%Ni/5A catalyst exhibited the highest NH₃ conversion and a high H₂ formation rate of 23.5 mmol/g_cat·min (30,000 mL/g_cat·h, 600 ℃). This performance was attributed to the strong metal-support interaction and the enhancement of N₂ desorption rates through the presence of medium basic sites.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.188-196
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• 2023

Wheat (Triticum aestivum L.) is an important crop in Korea, with a per capita consumption of 31.6 kg in 2019. In the southern region, wheat is grown after paddy rice, and it is harvested during the rainy season in mid-June. This timing, in combination with high humidity and untimely rainfall, activates the enzyme alpha-amylase, which breaks down starch in the wheat grains. As a result, sprouted grains have lower quality and value for flour. However, seeds that absorb water before sprouting are expected to maintain better quality. The aim of the study was to identify the critical period during wheat maturation when rainfall has the greatest impact on grain quality, to prevent price declines due to quality deterioration. Two wheat cultivars, Jokyoung and Hwanggeumal, were grown in a speed breeding room, and artificial rainfall was applied at different times after heading (30, 35, 40, 45, 50, and 55 days). The proportion of vitreous grains decreased from 40 to 55 days after heading (DAH). Both cultivars had chalky grain sections from 35 DAH, with Hwanggeumal having a higher proportion of vitreous grains. Starch degradation was observed using FE-SEM (Field Emission Scanning Electron Microscope) at 40 DAH for Jokyoung and 50 DAH for Hwanggeumal. Color measurements indicated increased L and E values from 40 DAH, with rain treatment at 55 DAH leading to a significant increase in L values for both cultivars. Ash content increased at 45 DAH, whereas SDSS decreased at 35 DAH. Overall, grain quality from 40 DAH until harvest was found to be affected to the greatest extent by direct exposure of the spikes to moisture. Red wheat showed better quality than white wheat. These findings have implications for the cultivation of high-quality wheat and can guide future research efforts in this area.

• Journal of Public Diplomacy
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• v.3 no.2
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• pp.35-52
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• 2023

Korea has developed as an influential country over Asia and all over the world based on remarkable economic development. And the background of this development was possible due to the existence of those who sacrificed precious lives and contributed to the nation's existence in the past crisis. Every year, Korea holds an annual commemorative event with people of national merit, Korean War veterans, and their families, expressing gratitude for sacrifices and contributions at home and abroad, and providing economic support. The tragedy of the Korean War and the pro-democracy movement in Korea over the past half century will one day become a history of the distant past over time. As generations change and the purpose and method of exchange by region change, the tragic situation that occurred earlier and the way people sacrificed for the country are expected to be different from before. In particular, it is true that the number of Korean War veterans and their families is gradually decreasing as they are now old. In addition, due to the outbreak of global infectious diseases such as COVID-19, it is difficult to plan and conduct face to face events as well as before. Currently, Korea's digital technology is introducing various methods. 5G communication networks, smart-phones, tablet PCs, and smart devices that can experience virtual reality are already used in our real lives. Business meetings are held in a metaverse environment, and concerts by famous singers are held in an online environment. Artificial intelligence technology has also been introduced in the field of human resource recruitment and customer response services, improving the work efficiency of companies. And it seems that this technology can be used in the field of veterans. In particular, there is a metaverse technology that can vividly show the situation during the Korean War, and a way to digitalize the voices and facial expressions of currently surviving veterans to convey their memories and lessons to future generations in the long run. If this digital technology method is realized on an online platform to hold a veterans' celebration event, veterans and their families on the other side of the world will be able to participate in the event more conveniently.

• Clean Technology
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• v.29 no.4
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• pp.288-296
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• 2023

Coal is abundantly available compared to other energy sources and is used as a versatile energy resource worldwide. To address the environmental issues stemming from conventional coal utilization, efforts are underway to develop clean coal utilization technologies, with IGCC technology being a notable example. In IGCC plants, coal is subjected to a CMD process where both drying and pulverization are achieved by supplying hot air. However, if the temperature of the supplied hot air is excessively high, it can lead to devolatilization and spontaneous combustion, thereby compromising the stable operation of the CMD process. This study aimed to measure the devolatilization and spontaneous combustion temperatures of different types of bituminous coal, and to explore their correlations with the characteristics of the coals. Six coal types exhibited devolatilization between 350 and 400 ℃, while three coal types showed devolatilization at temperatures exceeding 400 ℃. Spontaneous combustion ℃curred in one coal type below 100 ℃, six coal types between 100 and 150 ℃, and two coal types above 150 ℃. The measured initiation temperatures were compared with the coal characteristics including the oxygen, moisture, Fe₂O₃, and CaO content, the H/C ratio, and the O/C ratio to establish correlations. Regression analysis was used to calculate the regression coefficients and determination coefficients for each ignition temperature. It was found that 52.44% of the FC/VM data significantly influenced the volatile matter ignition temperature, and 59.10% of the Fe₂O₃ data significantly affected the spontaneous combustionignition temperature.

• Journal of Technology Innovation
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• v.31 no.3
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• pp.39-73
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• 2023

The field of Management of Technology(MOT) emerged in response to the need for research management within U.S. public research institutions during the 1960s. Since its inception, it has proliferated significantly, being practiced in more than 809 institutions globally and over 19 institutions in Korea, encompassing both research and educational endeavors. Particularly noteworthy is the substantial investment of government resources, primarily channeled through the Ministry of Industry since 2007, which has expeditiously established a comprehensive framework for cultivating graduate-level MOT expertise, marked by both quantitative and qualitative advancements. The educational curriculum in the realm of Korean MOT deviates from foreign counterparts through distinctive pathways, exemplified by its emphasis on industry practice-oriented educational programs, standardization and isomorphism across different schools, as well as its interconnectedness with proximate academic disciplines. This research systematically undertakes an analysis of the curriculum in Korean MOT graduate schools, thereby ascertaining its intrinsic identity and distinct attributes. In this endeavor, a comprehensive examination of eleven principal MOT textbooks(three in Korean and eight in English) is conducted to delineate the primary content of the curriculum across seven thematic domains. Moreover, the study deliberates on its differentiation from neighboring academic disciplines and the definitional attributes of MOT. Subsequently, this analysis also encompasses nine Korean MOT graduate programs, projecting the seven thematic domains onto their respective curricula. The findings illuminate that within the context of Korean graduate programs, a substantial proportion of the curriculum, amounting to 62.5%, is dedicated to facets encompassing the operational aspects of technology management within corporate contexts, technology management specific to varying industries and technologies, and collaborative endeavors between academia and industry in the form of projects and seminars. Evidently, the Korean approach to technology management education is notably geared towards the cultivation of adept practitioners capable of executing technology management functions at a mid-tier managerial level, aligned with the exigencies of regional industries. Grounded in the analysis of technology management curricula, this study extrapolates implications for the future trajectory of MOT education in Korea, encompassing a consideration of the stages of industrial development. It underscores the necessity to augment the educational curricula pertaining conceptual foundation of technology and innovation, strategic perspectives of technology and innovation, and the socio-economic context of technology management.

• Journal of Industrial Convergence
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• v.22 no.6
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• pp.99-106
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• 2024

The author thought about how to explain visual functions in an easy-to-understand way to customers visiting the optical shops and provide easy customer consultation, and attempted to evaluate the usability and value of the educational webtoon for patient consultation by applying it to the optical shops's visitors. Survey study was conducted targeting 152 customers who visited optical shops A in Incheon from January to December 2023. In this study, consultation was conducted using educational webtoons to help the general public understand concepts that are difficult to understand, such as binocular vision function, the concept of heterophoria, prism lenses, and binocular balance. The areas of 'understanding', 'interest', 'usability', 'necessity', and 'expression of expertise' felt by the visitors who received counseling were scored and evaluated, and differences according to counseling method were evaluated using an independent sample t-test. Statistical verification was performed. When the optometrist only explained verbally, the score distribution was relatively low: 1.96 points for understanding, 2.06 points for interest, 2.96 points for usability, 4.20 points for necessity, and 3.19 points for expertise. When the optometrist provided explanations along with the book, understanding was 4.14 points, interest was 3.28 points, usability was 3.60 points, necessity was 4.17 points, and expertise was 3.55 points. When the optometrist explained with a webtoon, understanding was 4.57 points, interest was 4.96 points, usability was 4.18 points, necessity was 4.65 points, and expertise was 3.15 points. When explanations were given only verbally, all items showed the lowest scores, whereas consultations using webtoons showed 4 points or more (excellent) in all items except the 'expression of expertise' item. It is evaluated that actively using webtoons in various consultation situations that occur in optical shops will help increase customer interest and concentration.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.34-48
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• 2024

The objective of this study was to evaluate the safety of biodegradable mulching films in soybean (Glycine max) cultivation by measuring their effects on crop growth and yield, film decomposition and soil chemical and physical properties. In 2022 and 2023, plant height, branch number, chlorophyll contents, yield components, and yield of soybean did not vary significantly in areas using PE films and biodegradable mulching films. The light transmission rate of the biodegradable mulching films ranged from 6.4 to 15.8% when measured 112 days after soybean transplanting, and was higher, on average, in 2023 than in 2022. In both years, degradation of the biodegradable mulching films began 20 days after soybean transplantation and increased over time. In addition, remains of biodegradable mulching films were present in fields at soybean harvest and remained until 50 days after harvest. Decomposition rates of the biodegradable mulching films at 112 days after soybean transplanting ranged from 9.8 to 26.7% in 2022 and 13 to 36% in 2023. Although soil pH and EC varied based on the year and timing of measurements, there was no significant difference between areas that used biodegradable mulching films and PE films. Soil organic matter, nitrate and exchangeable cation contents such as Ca, Mg, and K were not significantly different in areas that used both PE films and biodegradable films. However, significantly higher levels of available phosphoric acid content were measured in areas that used biodegradable mulch films E, S, and T. Regardless of which films were used, there were no significant differences in the soil's physical properties. In 2022 and 2023, there was no difference between areas that used biodegradable mulch films and PE films. However, soil temperature in mulched areas was 2℃ higher and soil moisture was 5-15% higher than in non-mulched areas. Barley growth was not affected by being planted in soil that had been used for soybean cultivation with biodegradable films. Therefore, the biodegradable mulch films used in this study can be used without negatively affecting the growth, yield, and soil environment of soybeans.