• East Asian mathematical journal
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• v.31 no.2
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• pp.145-165
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• 2015

The purpose of this study is to suggest how to go about teaching and learning secondary school algebra by analyzing problem-solving ability and problem-solving process through algebraic reasoning. In doing this, 393 students' data were thoroughly analyzed after setting up the exam questions and analytic standards. As with the test conducted with technical school students, the students scored low achievement in the algebraic reasoning test and even worse the majority tried to answer the questions by substituting arbitrary numbers. The students with high problem-solving abilities tended to utilize conceptual strategies as well as procedural strategies, whereas those with low problem-solving abilities were more keen on utilizing procedural strategies. All the subject groups mentioned above frequently utilized equations in solving the questions, and when that utilization failed they were left with the unanswered questions. When solving algebraic reasoning questions, students need to be guided to utilize both strategies based on the questions.

• Journal of Ocean Engineering and Technology
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• v.19 no.5 s.66
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• pp.50-57
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• 2005

This study has been conducted to investigate corrosivity of carbon steel, Cu, Zn and Al for one year from Sept. 2003 to Aug. 2004. A model of ISO 9223-ISO 9226 that represents the relation between metal corrosions and environmental parameters was used for atmospheric corrosion evaluations. Environmental parameters for these evaluations are time of wetness(TOW), $SO_2$ and Chloride. Corrosion rates for four metals which are exposed indoors and outdoors were measured on five locations in Jeju Island; Gosan, Seogwipo, Seongsan, Chuna hill and Jeju city. The environmental factor of atmospheric corrosion of Jeju Island for $SO_2$ class is P0, a clean area. TOW as T3 and T4 indicates that Jeju has the characteristics of a tropical area. Chlorides class within 3 km from the coast show the features of costal area as S2 and S3 classes. Chuna hill show the features of woodland as a S1 class. In Corrosion classes of each site which was measured outdoors is higher than indoors. Gosan is the highest class as the rank of C5, and indicated that they're ranked as C3 or C4.

• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.17-25
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• 2015

The main objective of this study is to predict the wind power generation at the wind farm using various wake models. Modeling of wind farm is a prerequisite for prediction of annual energy production at the wind farm. In this study, we modeled 20 MW class Seongsan wind farm which has 10 wind turbines located at the eastern part of Jeju Island. WindSim based on the computational fluid dynamics was adopted for the estimation of power generation. The power curve and thrust coefficient with meteorology file were prepared for wind farm modelling. The meteorology file was produced based on the measured data of the Korea Wind Atlas provided by Korea Institute of Energy Research. Three types of wake models such as Jensen, Larsen, and Ishihara et al. wake models were applied to investigate the wake effects. From the result, Jensen and Ishihara wake models show nearly the same value of power generation whereas the Larsen wake model shows the largest value. New positions of wind turbines are proposed to reduce the wake loss, and to increase the annual energy production of the wind farm.

• Journal of Korea Planning Association
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• v.53 no.7
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• pp.87-107
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• 2018

With more than 10 million inhabitants, in particular, Seoul, the capital of Korea, has already experienced a number of severe heat wave. To alleviate the potential impacts of heat wave and the vulnerability to heat wave, policy-makers have generally considered the option of heat wave strategies containing adaptation elements. From the perspective of sustainable planning for adaptation to heat wave, the objective of this study is to identify the elements of vulnerability and assess heat wave-vulnerability at the dong level. This study also performs an exploratory investigation of the spatial pattern of vulnerable areas in Seoul to heat wave by applying exploratory spatial data analysis. Then this study attempts to select areas with the relatively highest and lowest level of adaptive capacity to heat wave based on an framework of climate change vulnerability assessment. In our analysis, the adaptive capacity is the relatively highest for Seongsan-2-dong in Mapo and the relatively lowest for Changsin-3-dong in Jongno. This study sheds additional light on the spatial patterns of heat wave-vulnerability and the relationship between adaptive capacity and heat wave.

• Journal of Marine Bioscience and Biotechnology
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• v.13 no.1
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• pp.48-57
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• 2021

Vibrio species are Gram-negative basophils that are ubiquitous in seawater, increasing in number as the water temperature increases. Humans are usually infected by the consumption of contaminated seawater or seafood. V. alginolyticus infection in humans is mainly associated with infections of the skin and ears, such as acute otitis media and cellulitis. In this study, the distribution of V. alginolyticus along the coast of Jeju Island, and its relationship with water temperature, salinity, DO, and pH was investigated. The antibiotic susceptibility of the bacteria isolated was also tested. In seawater, the Daejeong area had the highest detection rate, with 13 cases (21.7%), and the Hallim area showed the lowest detection rate, with eight cases (13.3%) in. In shellfish, the Daejeong area had the highest rate, with seven cases (23.3%), and the Seongsan and Hallim areas had the lowest detection rate, with four cases (13.3%). The overall detection rate was the highest in Daejeong area, with 20 cases (22.2%), and the lowest in the Hallim area, with 12 cases (13.3%). The detection rate was highest when the water temperature was highest.

• The Journal of Information Systems
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• v.30 no.2
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• pp.189-214
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• 2021

Purpose This paper aims to effectively utilize user-generated content (UGC) and analyze the market structure of a relatively new market which lacks rich user review information. Specifically, we propose a domain-specific text mining tool for the domestic craft beer market and visualize the market structure by incorporating how individual beer products are positioned in the perceptual map of consumers. Design/methodology/approach We collect user review information from Naver blogs, and extract words that describe beers. We identify semantic relationships between beer products through text mining, and then depending on these semantic relationships, construct a graph representing the market structure of the domestic craft beer market based on the consumer's perceptual map. Findings First, beer products produced in the same brewery are perceived as very similar to consumers. Second, only two products, 'Heukdang Milky Stout' and 'Gompyo', was noticeably distinguishable from other products. Third, even though 'Gyeongbokgung' is from a different brewery, it is located very close to the products of 'Jeju Beer' brewery such as 'Jeju Baeknokdam Ale' and 'Seongsan Ilchulbong Ale', which suggests the influence of 'landmark series.' We successfully show that our methodology effectively describes the market structure of the craft beer market.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1507-1516
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• 2020

This study analyzed the scenario for road freezing section by applying the road freezing evaluation algorithm. To apply road freezing algorithm, the influencing factors on road freezing were reviewed. Observation data from four points, Mokgam IC, Jeongneung tunnel, Seongsan bridge, and Yeomchang bridge were used for analysis. All observatories are installed on the expressway, and they are classified for the analysis of road freezing characteristics. When the difference between the road surface temperature and dew-point temperature of the road freezing evaluation algorithm was 3℃ or less, the section where road freezing occurred was checked. In addition, road freezing evaluation was derived through the change of the road surface condition and water film thickness of the freezing section.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.75-83
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• 2004

July 1, 2004 Seoul Metropolitan city is operating the Median Bus Lane System on Gangnam Main Street, Seongsan-Susaek-ro (Road) and Dobong- Mia-ro (Road) as one of the systematic reorganizations in public transportation. It has been assumed that there was an improvement in the speed of bus considering that the Median Bus Lane System practiced on Cheonho-daero (Main Street) since 1996 have had 35km/h on the average. If the Median Bus Lane goes into effect, there is a problem with the left turn on the crossroad. The buses go on the existing first lane so that the left fuming cars cannot help but turn left on the second lane. In case that the Median Bus Lane is put into practice, the left turn on the crossroad should not be allowed. However, if the left turn is not permitted on the crossroads in the aforementioned main streets, neighboring residents will complain about it and there will be some difficulties in finding other detour. On the premise that the prevalent left turn on the crossroads is allowed while the Median Bus Lane is being put into practice, this study suggests the separation of a stop line between buses and other vehicles as a way of fuming left in a safe manner and a way to calculate the appropriate distance.

• Journal of the Korea Fashion and Costume Design Association
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• v.18 no.2
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• pp.35-49
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• 2016

Dopo was the clothing of the Joseon period, which had a strong value of Confucianism. Apart from the kings and princes, government officers and Confucian literati wore Dopo as their official clothing and the uniform. The basic form of Dopo had the straight collar similar to Jikryeong. The difference is the shape of a Mu, which was fixed inside or on the back section along the side line of the front section and made two flaps on the back section. The clothing found in the tombs of Bae Cheonjo (1532~?) are from the mid-16th century to the early 17th century with the clothing style of the early Joseon period. The outer collar of all clothing was the shawl collar except for the Sibok and the inner collar was sewn to this. Two items had square tray collars, which were folded in half and sewn inside in half. The sleeve had a straight inseam from the armhole and its end around the wrist was round and wide. The carp-shaped inseam of the sleeve and wide sleeve indicated a change of sleeve shape. The shapes of the collars and the wide overlapped section of the dual collars demonstrated the shapes of the initial outer robes. The man's outer coats with wide sleeves were mostly cotton-quilted clothing. As described above, this paper examines the basic shapes of outer robes including Sibok, Jikryeong and man's outer coats on the basis of the clothing and artifacts from the tomb of Bae Cheonjo (1532~?) and examined the shapes, composition and features of Dopo. This paper aims to improve awareness of the wisdom and spirit of ancestors in life hidden in the sewing of the three Dopo items and on the importance of historical research.

• Journal of Korean Elementary Science Education
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• v.31 no.2
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• pp.197-207
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• 2012

The purpose of this study was to assess pro-environmental behavior of elementary school students by school year and gender and to investigate the relationships of their emotional affinity toward and intellectual curiosity about life, and experiences about nature and life with the pro-environmental behavior. A total of 436 elementary students participated in the study: 189 3rd grade; 247 6th grade students, and 233 boys; 203 girls. The variables were measured by using a self-report questionnaire with 5-point Likert scale items. The results showed the levels of pro-environmental behavior of the 3rd grade students and the girls were higher than that of the 6th grade and the boys, respectively. Their pro-environmental behavior was significantly related with all measured variables. However, it was found that the direct predictors of their pro-environmental behavior were the intellectual curiosity and the indirect experience, while the emotional affinity and the direct experience did not have a direct impact on the behavior. The predictive power of the intellectual curiosity and the indirect experience for their pro-environmental behavior was higher in 3rd grade than 6th grade. While the indirect experience was a stronger predictor of the boys' pro-environmental behavior than the intellectual curiosity, the curiosity was a stronger predictor of the girls.