• Korean Journal of Ichthyology
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• v.33 no.3
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• pp.177-183
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• 2021

Distribution aspects and extinction threat evaluation of the endangered species, Rhynchocypris semotilus were investigated in Goseong-gun, Gangwon-do, Korea, June 2020. Among the 12 sampling sites investigated during the study period, samples of R. semotilus were collected 268 individuals at 6 sites. The streams inhabited of R. semotilus were Songhyeoncheon (3 stations), Gojindong (2 stations) and Osodong (1 station). The main habitats of R. semotilus were uppermost and upper stream (Aa type) with 3~15 m water flow width, 0.3~1.3 m depth and high ratio boulder and cobble bottoms. The estimated age of the R. semotilus (June) based on their total length distribution indicated that 0-, 1-, 2-, 3- and more than 4-year-old were 6~27 mm, 38~59 mm, 60~75 mm, 78~93 mm and 96~125 mm, respectively, and their has matured reproductive organs over two years old. R. semotilus investigation results of the threat of extinction showed no tendency to decrease in population size, but estimated to be less than 1,000 mature individuals, with a small range of extend of occurrence (39.668 km²), area of occupancy (16 km²), and number of disconnected locations (3 locations). Therefore, R. semotilus is now considered vulnerable (VU D2) based on the IUCN Red List categories and criteria.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.3
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• pp.34-45
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• 2019

Based on the analysis of congestion conditions in small cities with a population of less than 500,000 in Chungcheong Province, this study conducted a feasibility study on the scope of congestion improvement projects. Further, traffic congestion management standards were further established by analyzing LOS as well as the speed of traffic presented by congestion criteria in the existing Project. According to the analysis according to the congestion management standard LOS suggested in this study, Asan city has the most major number of highways where LOS E occurs for more than 3 hours, followed by Sejong City and Gongju City. In addition, when comparing the ratio of the busy main roads according to the frequency of LOS E by city size, it was analyzed that the ratio and extension of the busy highways relative to the overall extension of the large Chungcheong area are similar to the ratio in small cities in the Chungcheong region. Therefore, traffic congestion occurred in small cities and the feasibility of the improvement project was revealed.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.140-149
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• 2018

Along with the recent increase in national income, social phenomena such as aging due to a decrease in population and an increase in single households are observed. There are also an increasing number of households raising pets in proportion to aging households and the increase in the number of single households, most of which use animal companions to overcome loneliness and boost domestic vitality. As more and more people consider pets as family members, the size of the domestic pet market is also growing. The growing number of pets in older households and single households is not properly managed by care such as food meals and exercise management for pets. It is necessary to research and develop robots that can monitor animal companions remotely, feed a certain amount of food at regular intervals, and manage their health through exercise. Among pet companions, dog selection is the highest. Therefore, this study identified robot research on driving methods, examples of existing pet care systems, and researched pet care robots using obstacle avoidance algorithms. In order to use the snack pay behavior and obstacle avoidance algorithm of the pet animals by applying IoT and we .oPI technology, it is able to use ultrasonic sensors on the front and has four infrared sensors on the back. However, this study does not reflect the characteristics of other pet animals as a study on pet care robots, and it requires continuous observation and testing.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.153-162
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• 2018

This paper analyzed the current level of the middle school academic achievement in Changwon City and explored the ways for improving academic achievement of the middle school in Changwon City. The data used in the analysis were the results of National Assessment of Educational Achievement of middle school students from 2013 to 2016 which was released on the school's information website(www.schoolinfo.go.kr) First, the analysis found that the academic achievement level of the middle school in Changwon City was not higher than those of Gwangju, Daejeon, and Ulsan, where the population size is similar. Second, the level of academic achievement among middle schools in Changwon City differed by year. Third, the level of academic achievement of middle school in Changwon City differed by district. Fourth, the educational achievement gap among middle schools in Changwon City existed by public and private school, as well as by male school, female school, and male and female Middle School. The paper suggested that schools with low ratio of proficient and above achievement levels should look for ways to raise the percentage of proficient and above achievement levels, and schools with higher rates of below basic achievement should make efforts to solve the problem.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.81-91
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• 2019

Although the number of users of urban railways is greatly influenced by the land use plan around the railway station, Korea has been studying this problem in a small scale, so that the entrance width is uniformly calculated irrespective of the land use plan, And there is little deviation. Therefore, this study aims to establish a demand estimation model for the entrance and exit of urban railway stations. For this purpose, the demand, land use area, and socioeconomic indicators for each of the 20 urban railway stations were surveyed at 200m and 500m Regression model. The model is based on the assumption that the dependent variable (response variable) of the model is set to 1 day, peak 1 hour, peak time 5 minutes, Education, and park) and socioeconomic indicators (population, employer, employee, and student) as independent variables (explanatory variables). As a result, it was analyzed that the fit of the model is more statistically significant when the use area of the land use by 500 meters of the center radius of the city rail is used as an independent variable and the demand for the daily use of the railway station is used as a dependent variable. The purpose of this study is to estimate the optimal size of urban railway entrance in order to improve the mobility of the user and the transportation weak in urban railway station.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.694-700
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• 2018

To investigate the effect of heavy metals (Cu, Cd, Hg, Pb, Zn) on mosquito Culex pipiens, 50% lethal concentration ($LC_{50}$) concentration, total lipid content, lipid content composition, and total protein content were measured. The results showed that the Hg $LC_{50}$ was $0.45mg\;kg^{-1}$ and the Hg toxicity was higher than the other metals. The results also showed that cadmium (Cd) significantly retarded the growth of mosquito larvae among the tested heavy metals. Six types of lipid bands were isolated from mosquito samples exposed to heavy metals, and five of them were identified (phospholipid, cholesterol, fatty acid, triglyceride, and cholesterol ester). The total lipid content of all treatments decreased compared to the control. In addition, the protein content of the control group ($0.51mg\;ind.^{-1}$) was higher than that of the treated group, and the protein content of the larvae treated with Hg and Cd was very low. In conclusion, heavy metals not only lower the survival rate of mosquitoes, but also affect the protein content and lipids in the mosquito's body, thereby causing growth inhibition. These results indicate that heavy metal contamination will affect the size of mosquito population by inhibiting the survival and growth of mosquitoes, and it is expected that it can be used to measure the degree of contamination using mosquito through subsequent studies.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.67-76
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• 2019

This study was conducted from 2017 to 2018 to determine habitat aspects of Acheilognathus signifier, an endangered species reintroduced (2010~2012) to Heukcheon Stream, a tributary of the Hangang River, Korea. A total of 329 individuals were collected in 2017 (two surveys) and 723 individuals were collected in 2018 (four surveys) at about 5 km habitat area, including the discharge station. A. signifier's habitat was about 0.4 to 1.2 meters deep in slow water flow upstream of the discharge area. It was a place with many boulders and cobbles. The spawning period was estimated from April to June in terms of spawning behavior and collected juvenile size. Sex ratio of females (438) and males (412) was 1 : 0.94. Estimated age of A. signifier based on their total length distribution during the spawning period (April) indicated that 1-, 2-, 3-year old groups and more than 4-year-old group were 32~43 mm, 50~61 mm, 62~75 mm, and 76~89 mm, respectively. Age-specific composition costs differed depending on the timing of the collection. They were relatively high in the order of first-year (juvenile)>third-year> and fourth-year or higher, showing a stable age structure. Thus, A. signifier reintroduced to Heukcheon Stream has successfully settled down and formed a stable population, showing a tendency to proliferate.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.136-142
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• 2019

Water spider(Argyroneta aquatica) inhabits only a small size wetland in Eundae-ri, Yeoncheon-gun. In this study to investigate environmental factors influencing on population of A. aquatica, we analyzed the relationship between density of A. aquatica and various physicochemical and biological factors. Density of A. aquatica increased with small habitat area and high $NH_4$ and electric conductivity. The relationship between density of A. aquatica and prey or predator was low but the water spider decreased with density of Pomacea canaliculata. And density of A. aquatica was not related to the coverage of emergent plant. However density of A. aquatica decreased as the increase of floating plant and increased as the increase of submerged plant. These results indicated that aquatic plants are important in the habitat environment of A. aquatica. Therefore we suggest necessity of management strategies for the invasive species, P. canaliculata which is a notorious predator of aquatic plants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.252-266
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• 2019

The purpose of this study was to identify the type of health behaviors in Korean adults and to identify related factors. The data used in the analysis was the Korea Health and Nutrition Examination Survey 2014., which was representative of the Korean population. Cluster analysis was used to find the pattern of clustering of smoking, drinking, exercising and nutrition. Differences in the pattern of clustering was examined, first by bivariate chi-square test, and then by multinomial logit regression. Lastly, the association between the clusters of health behaviors and other behavioral risk factors was tested by chi-square test and logistic regression. The distribution of the clusters varied not only across socioeconomic characteristics and local size, but also between individuals with certain chronic diseases and those without. The results of this study can be used as a basis for the usefulness of approaching the cluster rather than individually approaching the health behavior.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.1-13
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• 2019

The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) resulted in the deposition of large quantities of radionuclides over parts of eastern Japan. Radioactive contaminants have been observed over a large area including forests, cities, rivers and lakes. Due to the strong adsorption of radioactive cesium by soil particles, radioactive cesium migrates with the eroded soil, follows the surface flow paths, and is delivered downstream of population-rich regions and eventually to coastal areas. In this study, we developed a model to simulate the transport of contaminated sediment in a watershed hydrological system and this model was compared with observation data from eroded soil observation instruments located at the Korea Atomic Energy Research Institute. Two methods were applied to analyze the soil particle size distribution of the collected soil samples, including standardized sieve analysis and image analysis methods. Numerical models were developed to simulate the movement of soil along with actual rainfall considering initial saturation, rainfall infiltration, multilayer and rain splash. In the 2019 study, a numerical model will be used to add rainfall shield effect by trees, evaporation effect and shield effects of surface water. An eroded soil observation instrument has been installed near the Wolsong nuclear power plant since 2018 and observation data are being continuously collected. Based on these observations data, we will develop the numerical model to analyze long-term behavior of radionuclides on land as they move from land to rivers, lakes and coastal areas.