• Composites Research
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• v.34 no.1
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• pp.35-46
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• 2021

This paper aims to reduce weight by replacing the reinforcements of the B-pillar used in vehicles with CFRP(Carbon Fiber Reinforced Plastics) and GFRP(Glass Fiber Reinforced Plastics) from the existing steel materials. For this, it is necessary to secure structural stability that can replace the existing B-pillar while reducing the weight. Existing B-pillar are composed of steel reinforcements of various shapes, including a steel outer. Among these steel reinforcements, two steel reinforcements are to be replaced with composite materials. Each steel reinforcement is manufactured separately and bonded to the B-pillar outer by welding. However, the composite reinforcements presented in this paper are manufactured at once through compression and injection processes using patch-type CFRP and rib-structured GFRP. CFRP is attached to the high-strength part of the B-pillar to resist side loads, and the GFRP ribs are designed to resist torsion and side loads through a topology optimization technique. Through structural analysis, the designed composite B-pillar was compared with the existing B-pillar, and the weight reduction ratio was calculated.

• Journal of Korean Historical Folklife
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• no.28
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• pp.113-142
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• 2008

The purpose of this script is to understand general issues related to production of visionary drawing and correct the fault of previous research by examining the data on visionary drawing featured on Ok So Kwon-Seop's anthology, "Oksogo(玉所稿)" the summary of its contents are as follows. First by analyzing the status of visionary drawings, in among "Oksogo(玉所稿)" which is Ok So's manuscript collection, there are 56 pieces in Je Chun Bon (edition) and 47 in Moon Kyoung Bon(edition). And recorded dreams in visionary drawings are centralized when Ok So was in his late 50's to 70's. And it is estimated that the visionary drawings are the collection of work done by many artists in long period of time. It was confirmed that Kwon Seop himself did not participated in drawings but were done by his brother Kwon Young, his grandson Kwon Shin Eung and Cho Se Gul, the artist from Pyoung Yang. Also visionary drawings were produced in youth years and among the visionary drawings that can be ascertain about the produced year and the oldest is by Cho Se Gul which was estimated to be done in 1695. And the last one to be completed was which was a dream in 1756 turned into a drawing and this was produced between 1756 to 1759 which was a year Ok So passed away. Production of Ki Seung Chup (album) or Mong-Wha Chup (album) was accomplished as follows. When Ok So records his dream in writing he receives response poem from a person he was in dream with and ask artist to draw the vision in dream, then the drawing and scripts were compiled and made into an album. With this some of the issues on visionary drawings featured on "Oksogo(玉所稿)" would have been settled. Recently, 2 more volumes of Ok So's anthology were photo-printed and published and hopefully those issues that was unable to settle in this script will have more detailed answers by discovering new and undisclosed data.

• The Journal of Korean Philosophical History
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• no.53
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• pp.35-61
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• 2017

The formation process of Dasan(茶山)'s Yi Xue(易學) in Xinghuxuepai(星湖學派) was examined. Dasan(茶山)'s Yi Xue(易學) succeeded to the methods of Huti (互體) and Yaobian(爻變) from Seong-ho(星湖) and Ha-bin(河濱), and Dasan(茶山) thought that he couldn't cover Zhouyi("周易") just with this one method. So he suggested the four methods called Yilisifa(易理四法), and supplemented it with 18 methods through Duyiyaozhi(?讀易要旨?). Accordingly, the process of how Dasan(茶山)'s Yi Xue(易學) was established was examined one by one. Dasan(茶山) succeeded to the method of Huti(互體) from Seong-ho Lee Ik(星湖李瀷), the leading master of Xinghuxuepai(星湖學派). Nevertheless, Dasan(茶山) argued that the method of Huti(互體) had been from Zhu Xi(朱子). However, this argument of Dasan(茶山)'s seems to have resulted from Zhengzu(正祖)'s academic research policy. As a way to interpret Zhouyi(?周易?), Dasan(茶山) succeeded to the method of Yaobian(爻變) from Ha-bin(河濱). However, Dasan(茶山) argued that Yaobian(爻變)was Zhu Xi(朱子)'s intention. He had no choice but this because of Zhengzu(正祖)'s academic research policy. Dasan(茶山) succeeded to the method of Huti(互體) from Seong-ho(星湖) and Yaobian(爻變) from Ha-bin(河濱), but Dasan(茶山) proposed the four key methods called Yilisifa(易理四法). Many researchers have argued that, as for Dasan(茶山)'s modern viewpoint, Dasan(茶山) developed Yi Xue(易學) in a similar way as Xihe Mauqiling(西河 毛奇齡). However, this viewpoint cannot be judged to have been similar as it was expressed when Dasan(茶山) himself criticized Xihe(西河)'s Jingxueguan(經學觀).

• Korean Journal of Ecology and Environment
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• v.54 no.2
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• pp.96-101
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• 2021

In this study, we wanted to obtain the information of the ecological impact of alien species on native fish communities. The Ichthyofauna and fish community in Joongchosan Reservoir and Bukchosan Reservoir in Gunsan-si Korea were investigated over the period from March to October 2020. During the survey period, a total of 1,895 individuals representing eight species, five families, and four orders were caught in the Joongchosan Reservoir. In the Bukchosan Reservoir, a total of 171 individuals were caught, representing seven species, five families, and three orders. The dominant species and subdominant species of Joongchosan Reservoir were Pseudorasvora parva (661 individuals, RA: 34.7%), and Rhodeus ocellatus (660 individuals, RA: 34.7%). Conversely, Micropterus salmoides (77 individuals, RA: 45.0%), and Carassius auratus (60 individuals, RA: 35.1%), were the two most common species in the Bukchosan Reservoir. The community indices showed a dominance of 0.697, diversity of 1.483, evenness of 0.713, and species richness of 0.928 in the Joongchosan Reservoir. In comparison, the community indices in the Bukchosan Reservoir showed a dominance of 0.801, diversity of 1.304, evenness of 0.670, and species richness of 1.167. This study confirms that the number of native fishes and the associated community diversity have decreased due to the influence of Micropterus salmoides. This highlights the need for removal of alien species from reservoirs, while simultaneously preventing future introductions.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.68-80
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• 2021

This study aimed to present the current status of exotic fish species, invasive species, and dominant species inhabiting the Cheonggyecheon stream. We conducted three samplings from April to October 2019. A total of 2,045 individuals from 27 species belonging to nine fish families were collected. There were five Korean endemic species (18.5%) including Coreoleuciscus splendidus, Sarcocheilichthys nigripinnis morii, Squalidus gracilis majimae, Zacco koreanus, and Odontobutis interrupta in the Cheonggyecheon stream. The dominant species was Zacco platypus (62.4%) and the subdominant species was Z. koreanus (9.8%). The length-weight analysis of the dominant species Z. platypus population showed a regression coefficient b of 3.3434 and a condition factor(k) of 0.0026, with a positive slope. The growth state of the Z. platypus population was identified as being in a very favorable condition. The Cheonggyecheon stream is considered to be an appropriate habitat for the Z. platypus population. Since the restoration, The Cheonggyecheon stream has had continuous problems due to the introduction of exotic species and invasive species and in this study, exotic species, Gyrinocheilus aymonier var.(gold type), and invasive species, Coreoleuciscus splendidus, which have not previously been reported in the Cheonggyecheon stream, appeared. Therefore, it is deemed necessary to prepare continuous publicity and management measures to prevent exotic species and invasive species from inhabiting the Cheonggyecheon stream.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.667-677
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• 2020

This study was conducted to investigate the fish fauna and characteristics of the Carassius auratus population in the Boryeong Reservoir in Chungcheongnam-do from October 2017 to June 2018. The collected fish were identified as 3,506 individuals of 15 species from a total of nine families. The dominant and subdominant species were H. nipponensis with 1,706 (48.6%) individuals and C. auratus with 1,021 (29.1%) individuals, respectively. The biomass of C. auratus (246,130g), P. fulvidraco(50,610g), C. cuvieri (14,730 g), S. asotus (11,560 g), and C. carpio (10,930 g) was analyzed. The results of the community analysis showed a dominant index value of 0.87 (±0.2), a diversity index value of 0.78 (±0.5), an evenness index value of 0.47 (±0.2), and a richness index value of 0.99 (±0.5). The length-weight analysis of C. auratus showed a regression coefficient b of 3.06, and a condition factor (K) of 0.0004 with a positive slope. The frequency distribution of the total length analysis of the C. auratus population inhabiting the Boryeong Reservoir showed a high distribution of lengths between 140-160 mm and a low distribution between 230-280 mm. The normalized difference water index (NDWI) was analyzed over the Boryeong Reservoir water surface from 2013 to 2014 using Landsat 8 channel data. The areas where the NDWI was decreased were located at the inflow site of Ungcheon Stream.

• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.265-276
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• 2021

This study investigated the characteristics of fish communities and river health in the Sincheon stream of Imgin River between April and October 2019. The survey collected 3,677 objects in 30 species belonging to 12 families from 23 survey stations. The dominant and subdominant species were Zacco platypus (28.4%) and Oryzias sinensis (13.6%), respectively, followed by Z. koreanus (11.8%), Rhynchocypris oxycephalus (11.7%), Carassius auratus (9.6%), and Pseudorasbora parva (7.9%) in that order. Among the fish species collected, 10 (33.3%) were endemic species in Korea. The exotic species were 5 (16.7%), including Micropterus salmoides, Lepomis macrochirus, Cyprinus carpio (Israeli type), Poecilia reticulata, and Xiphophorus maculatus. The land-locked species included Cottus koreanus and Rhinogobius brunneus, while C. koreanus was a climate change-sensitive species. The dominance of the fish community was low, and the diversity was high in the Sincheon mainstream, Sudongcheon and Cheongdamcheon, whereas Dongducheon and Sangpaecheon showed higher dominance and low diversity. The river health was very good and good in the uppermost and Sudongcheon areas, whereas the upper stream was normal, and the middle and lower streams were poor and very poor, respectively. The water quality was also mostly poor or very poor from the midstream to the downstream, and only Sudongcheon was very good. Therefore, the water quality had a great impact on fish habitat and eventually affected river health significantly. Although the water quality of Shincheon has improved each year, the introduction of several foreign species had a very negative effect. Improvement of river health in Shincheon requires water quality improvement and management of exotic fish species.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.297-303
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• 2021

In this study, nine major sites of Yulcheon stream, a principal tributary of the Seomjingang River, were surveyed from April 2020 to October 2020, and their fish fauna and community structure were analyzed. A total of five families and 19 species of fish were identified. Among the 19 species, seven species were found to be endemic to Korea: Rhodeus uyekii, Squalidus gracilis majimae, Microphysogobio yaluensis, Odontobutis interrupta, Cobitis tetralineata, Zacco koreanus, and Squalidus chankaensis tsuchigae. Among five families, the family Cyprinidae had the largest number of species (15), whereas the rest of the four families: Gobiidae, Odontobutidae, Cobitidae, and Osphronemidae, had one species each. The two dominant species in the family Cyprinidae were identified as Z. platypus and Z. temminckii. The community index of nine major sites of Yulcheon stream was 0.499 dominance, 2.279 diversity, 0.774 evenness, and 2.594 species richness. The number 3 site had 14 species, the largest number of species among all sites, and the dominance rate (0.480) was low, whereas diversity (2.173), and species richness (2.701) were the highest. As a result of cluster analysis, clusters matched according to the structure of the river types, but St. 9, which confirmed a relatively small number of populations, showed a structure similar to that of the upstream section. In the case of St. 5, a separate cluster was formed by a large number of species and populations.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.111-116
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• 2022

The purpose of this study is to evaluate the reduction effect of microbially activated peat on odor generated by livestock farms. The odor gas was measured by stirring the livestock manure sample with the existing litter and the microbially activated peat (Healtha Peat) was developed by this research team. In outdoor farm experiment, the measurements were performed by comparing broilers farm using rice husks and microbially activated peat as litter. The weight, mortality, shipment date, and odor levels (NH₃) were measured before and after experiment. The result showed that NH₃ levels were reduced by 100% in the Healtha Peat mixed group, Healtha Peat and rice husks mixed group. In the peat mixed group, Healtha Peat and saw dust mixed group showed reduce value at 99.6% and 99.1%, respectively. However the rice husks mixed group and saw dust mixed group showed a relatively weak NH₃ reduction effect with values of 57.5% and 84.8%, respectively. After 3 months, the Healtha Peat mixed group and Healtha Peat and rice husks mixed group showed the highest NH₃ reduction effect persistence. In the outdoor farm experiment, NH₃ was present in farms using rice husks, but not in farms using Healtha Peat. In farms using Healtha Peat, the mortality and NH₃ were reduced by 75% and >90%, respectively. The average body weight increased 18% and resulted to 10% decrease in the shipping date. These results implied that microbially activated peat has a clear effect on farm NH₃ reduction and affects the productivity of farm animals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.353-362
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• 2023

In this research, the usage status and characteristics of user big data of Mobike, a dockless bike sharing service introduced in Suwon city, were analyzed, and multiple regression analysis was performed to identify factors influencing the demand for dockless bike sharing service. For analysis, usage data of bike sharing system in Suwon city in 2019 were obtained, and they were organized by areas. As a result of analyzing the characteristics of the influencing factors selected for each area, it was found that the extension of bicycle roads shows high in areas with high demand for bicycles or adjacent areas. Also, the population of 10-30's shows high in areas with high demand for bicycles or adjacent areas. In addition, it was analyzed that the use of bike sharing system is high in areas with high maintenance rate of bicycle roads and large-scale residential and commercial facilities near residential districts and adjacent areas. As a result of the multiple regression analysis, it is analyzed that length of bicycle·pedestrian roads (non-separated), population of 10-30's, number of railway stations, number of schools, number of commercial facilities, number of industrial facilities factors were significant. It is expected that it may be possible to create an environment in which citizens want to use dockless bike sharing service by identifying factors affecting the number of stationless shared bicycles. Also, the results of data analysis are considered to be contributing to policy data to promote the use of dockless bike sharing.