• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.531-544
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• 2024

The purpose of this study is to analyze traffic flow characteristics according to the market penetration rate (MPR) of autonomous vehicles (AV) on road sections where bus rapid transit (BRT) is actually operating. Furthermore, the maximum traffic volume was set through estimation of future traffic demand, and traffic flow characteristics were analyzed through traffic simulation for each scenario considering of a combination of BRT introduction and AV's MPR. To test statistical significance, Kruskal-Willis test and Jonckheere-Terpstra test were used to examine the impact of the market penetration rate of Autonomous vehicles on travel time and delay time etc. At the same time, the existence of the order relationship among travel time data according to the market penetration rate of autonomous vehicle was examined. As a result of the analysis, it was founded that the travel time significantly decreased as the MPR of AV increases in both intermittent flow and continuous flow environments. In particular, in the case of continuous flow, the law of increasing returns was satisfied in the effect of increasing travel speed and reducing travel time as the MPR of AV increases. The results of this study are expected to be used as a basic information for design plans for road reconstruction and space utilization after the commercialization of AV in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.587-593
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• 2024

Recently, countries such as Japan and France are actively using three-dimensional development of land to secure available land. In Korea, too, the lack of available land within cities is a major problem, and in particular, the problem of decline due to disconnection due to division due to the railroad is emerging. As a solution to this, interest in three-dimensional development is increasing day by day, but the application or legal effectiveness of the concept is still lacking. Therefore, in this study, assuming that the Gyeongbu Line railway in Busan is underground, we attempted to apply the type of multi-dimensional development appropriate for each region to the land that would be created, and to predict how much it would contribute to urban competitiveness by arranging the necessary facilities for each part. To this end, we have developed an urban competitiveness index that can evaluate the layout of facilities by region, and since the range of the region is different from the existing evaluation indicator, it is judged that the three-dimensional development of the railway facility site can have a positive impact on the competitiveness of the city as a result of the prediction through a subjective survey.

• Journal of the Korea Institute of Building Construction
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• v.24 no.4
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• pp.393-402
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• 2024

The Korean Industrial Standard(KS) KS F 2527("Aggregates for Concrete") does not explicitly define criteria for clay mineral content in aggregates. This lack of clear quality standards and testing methodologies is further compounded by a scarcity of relevant research within both academic and industrial spheres. Consequently, the construction industry, encompassing both aggregate production and utilization, often overlooks the management of clay mineral content due to its perceived economic implications. This study addresses this gap by investigating the current state of regulations concerning clay mineral content in aggregates, exploring the causes of its occurrence, and evaluating its impact on concrete performance. The chemical composition of the clay minerals was determined to primarily consist of Al₂O₃, Fe₂O₃, and SiO₂, which are commonly found in clay. X-ray diffraction(XRD) analysis revealed that the predominant clay minerals were montmorillonite and illite, both known for their high absorption capacity. An examination of domestic and international standards for clay mineral content in aggregates demonstrated that the density and absorption rate specifications outlined in KS F 2527("Aggregates for Concrete") only offer indirect estimations of clay mineral levels. Furthermore, the investigation into the influence of clay mineral content on concrete performance suggests that a higher clay mineral content necessitates a corresponding increase in the unit quantity of aggregates to maintain adequate workability. This, however, has a detrimental effect on the compressive strength of the concrete.

• Journal of Christian Education in Korea
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• v.78
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• pp.231-262
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• 2024

This study aims to explore the impact of learners' gratitude tendencies on computer reasoning and digital efficacy in a Christian program utilizing metaverse, generative AI, and Scratch at each stage based on design thinking (Chapter I). The subjects of the study are learners who participated in a youth Christian program for two weeks on January 20th and 27th, 2024, consisting of 22 middle and high school students. Gratitude tendencies, computer reasoning, and digital efficacy were measured through post-program surveys, and simple regression analysis was conducted. Open-ended survey questions were used for learner perception analysis (Chapter II). The research results showed that learners' gratitude tendencies significantly influence computer reasoning. Additionally, learners' gratitude tendencies significantly affect confidence and familiarity among the sub-dimensions of digital efficacy, while not showing a significant impact on usefulness. The significance of this study lies in specifically exploring learners' experiential perceptions in metaverse, generative AI, and Scratch utilization in design thinking-based edutech programs in Christian education. It is hoped that the results.

• Journal of Wetlands Research
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• v.26 no.3
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• pp.285-297
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• 2024

This study, conducted in Geolpo-dong and Gamjeong-dong near Gimpo-Hangang New Town, examines an area adjacent to the Han River estuary, a major wintering ground for migratory birds. Over 59 surveys from October 2015 to March 2022 in four representative rice fields (sites A-D) recorded 44,942 individuals from 32 genera and 72 species. Site D, a large area near the Han River, exhibited high species diversity. Despite lower diversity in areas under development (sites A, B, C), ongoing species influx and utilization persist. The study focuses on Anser fabalis, a species predominantly utilizing rice fields, and identified their distribution characteristics. The analysis revealed 162 instances of population influx, with over a 30-fold increase observed across 39 surveys conducted over a 30-month period (October to March, '15~'22). The area, a key wintering site for migratory birds of Janghang Wetland, about 5 km from feeding sites, is heavily utilized by migratory geese, indicating the region's high value considering migration distance and anticipated continuous bird influx despite urban expansion. Therefore, future developments should preserve ecological corridors and connected stepping stone habitats to not only preserve existing habitats but to secure alternative feeding sites, ensuring smooth movements and mitigating habitat loss.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.703-712
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• 2017

In this study, the fat contents and fatty acid compositions of Korean beef (tenderloin, loin, strip loin, chuck roll, foreshank, top blade, top round, brisket point, center of heel, and ribs) and pork (tenderloin, loin, shoulder loin, foreshank, jowls, ham, eye of round, belly, skirt meat, and ribs) parts were investigated. The fat contents of Korean beef ranged from 5.25% (top round) to 35.94% (brisket point). The major fatty acids were palmitic acid (C16:0), stearic acid (C18:0), and oleic acid (C18:1, n-9); especially, oleic acid was the most abundant. Loin had similar fat content as ribs, but there were some differences in fatty acid composition. Linolenic acid (C18:3, n-3) and linoleic acid (C18:2, n-6) were the most abundant fatty acids in strip loin and ribs (38.63 mg/100 g and 564.71 mg/100 g, respectively). Arachidonic acid (C20:4, n-6) was only found in strip loin, top blade, and ribs, and its amounts were in the following order: ribs (2.50 mg/100 g)> strip loin (1.33 mg/100 g)> top blade (1.19 mg/100 g). Total trans-fatty acid (TFA) content of top round was the lowest among all parts, and the ratio of unsaturated fatty acid (UFA) was the highest in foreshank. The fat contents of pork ranged from 4.16% (tenderloin) to 18.47% (belly), but there was no significant difference in fat content between tenderloin, loin, foreshank, ham, and eye of round. The major fatty acids were palmitic acid, stearic acid, oleic acid, and linoleic acid, and their amounts were in the following order: oleic> palmitic> linoleic> stearic acid. Docosahexaenoic acid (C22:6, n-3) was only detected in belly, and the TFA content of belly was the highest. The ratio of UFA was highest in ham. These findings will be useful in the development of standardization data on fatty acid composition in different parts of Korean beef and pork.

• Journal of Aquaculture
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• v.8 no.4
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• pp.261-269
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• 1995

A practical control diet was prepared and compared with raw fish ($80\%$ frozen horse mackerel + $20\%$ commercial binder meal) and moist pellet ($50\%$ frozen horse mackerel + $50\%$commercial binder meal) diets to develop a practical diet formulation for Korean rockfish (Sebastes schlegeli). Korean rockfish averaging 68.5g were fed with the three experimental diets for 11 months. Final average body weight was approximately 330g and showed no significant difference between fish groups (P>0.05). Feed efficiency of fish from control diet was significantly lower than those of fish from raw fish and moist pellet diets (P<0.05). Protein and lipid retention efficiency of fish ranged $26.9-28.8\%$ and $86.5-110.2\%$, respectively, without any significant difference between the different diets. At the end of the experiment, chemical composition for the various parts of fish body and flesh quality of the raw fish were examined. The data showed that there was no significant difference between fish from the different diet groups for moisture, protein and lipid contents of whole body, liver, and dorsal muscle. Also, thirty three panelists did not find any difference in color, smell, texture, and taste of the raw fish flesh. These results suggest that Korean rockfish can be cultured with a laboratory practical feed without any negative effects on growth, nutrient utilization, chemical composition of fish, and quality of raw fish. Therefore, the next step in developing practical feed is to modify the control diet for improving fish performance and reducing feed cost.

• Journal of Aquaculture
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• v.6 no.1
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• pp.29-46
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• 1993

In order to determine the optimum digestible energy to protein (DE/P) ratio in diets for Korean rockfish, Sebastes schlegeli, $45\%$ and $40\%$ protein diets with graded levels of DE/P ratio were fed to average 36g and 80g fish, respectively. The DE/P ratios in the $45\%$ protein diets ranged from 7.4 to 10.0 kcal/g protein, while those in the $40\%$ protein diets varied between 7.5 and 8.9 kcal/g protein. Both in the $45\%$ and $40\%$ protein diets, the changes in the DE/P ratios did not affect either the daily weight gain or the feed efficiency. However daily protein retention, daily energy retention, nutrient utilization and chemical composition in carcass varied depending on the DE/P ratios. Thus based on these parameters as criteria, the optimum DE/P ratio for both the $40\%$ and $45\%$ protein diets, estimated to be about 8 kcal/g protein. DE/P ratios more than 8 kcal/g protein, led to the deposition of a large amount of body fat, especially in the viscera. Any protein-sparing effect was not observed with the increase of the energy content in the diets. Apparent digestibility coefficients determined by the indirect method, using $Cr_2O_3$ as an indicator, were around $90,\;98\%\;and\;70\%$, for protein, lipid and digestible carbohydrate respectively, without any distinct differences between the diets.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.10-19
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• 2000

Due to the urbanization, concentrated population, and limited land exploitation in the modern society, the environment surrounding that we live in is getting polluted more and more, and it has become hard even to let urban children experience the nature. This research was conducted to help people recognize the importance of our natural resources through the environmental education of elementary school and to use school's practical open-space for the Indigenous Plants education. The results of this study are as follows : First, the status of a plant utilization in our institutional education : There were 362 species totally of 124 species of Trees, 156 species of Herbs, 63 species of Crops, and 19 species of Hydrophytes which appear in the elementary school text book. Of all, the most frequently appearing species of tree were the Malus pumila var. dulcissima, Pinus densijlora, Citrus unshiu, Diospyros kaki. Second, the effect of plant education using the land around schools : The result of research on the open-space of the 19 elementary schools located in Mapo-gu showed that most of the species planted are the Juniperus chinensisrose, Hibiscus syriacus. Pelargonium inquinans in the order of size, and the plants appearing in text book were grown in the botanical garden organized in 7 schools. Especially most of the Indigenous Plants were being planted in botanical garden, and Pinus densijlora, Abeliophyllum distichum, Polygonatum var. plurijlorum, Liriope platyphylla and so on. Last, the result of this research on recognition of Environment, Planting education and Indigenous plants : It showed that educational necessity of students and teachers about environment and Indigenous Plants was more than 80%. The management of botanical garden was conducted by some teachers and managers. The results of this study suggested that we needed the reconstruction of curriculum, the efficient application of plant education for effectiveness of using school environment and monitoring continually and construction information sources for the better environment education in the elementary schools.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.308-316
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• 2013

Fresh ginseng has a limited storage life due to the quality change caused by microbial spoilage as well as physiological deterioration. The present study investigated the effects of 1-methylcyclopropene (1-MCP) treatment, an inhibitor of ethylene action, on the microbial growth and quality maintenance of fresh ginseng during storage. Harvested fresh ginsengs were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP for 20 hours at $4^{\circ}C$ and then stored at room temperature (RT) for 18 days or low temperature ($4^{\circ}C$) for 160 days. After 18 days of storage at RT, the percentage weight loss in 1-MCP treated fresh ginseng (8.3%) is lower than that of control (10.1%). During long-term storage at $4^{\circ}C$, weight losses were increased slightly until 120 days without difference between non-treated and 1-MCP ginsengs. In contrast, after 120 days of storage at $4^{\circ}C$, higher increase in weight loss was observed in non-treated ginsengs than in 1-MCP treated ginsengs. Respiration rate and ethylene production of fresh ginseng were reduced by 1-MCP treatments at RT. The 1-MCP treatment also resulted in lower microbial population compared to those of non-treated ginsengs at RT. However, in ginsengs stored at $4^{\circ}C$ for short-term (45 days), no differences were noted in weight loss and microbial population between 1-MCP treated and non-treated ginsengs. Major ginsenosides was not changed by 1-MCP treatment during the 7 days of storage at RT. Results suggest that 1-MCP treatment can be used to maintain the freshness of ginseng at room temperature for short term storage and at low temperature for long term storage. 1-MCP treatment could be applied on fresh ginseng to avoid deleterious effect of exogenous ethylene during storage and shipping.