• Journal of the Korean School Mathematics Society
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• v.21 no.4
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• pp.303-326
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• 2018

Fraction has difficulties in learning because of the diversity of meanings, the ways of presenting contents and teaching methods in elementary school mathematics. Therefore, the various strategies of teaching of fraction concept is proposed as an alternative. The problem of equal sharing problem is that children can experience the concept of fractions naturally in the context of everyday distribution. Even before learning formal fractions, children can solve them in various ways based on their own experiences. The purpose of this study is to investigate the degree of problem solving and problem solving strategies for children in 2nd, 4th, and 6th grades in elementary school. As a result of the research, the percentage of correct answers increased as the grade increased, but the grade levels showed a difference depending on the numbers given to the problems. Also, there were differences in the problem solving strategies according to the grade levels. Also, according to the numbers presented in the problem, the percentage of correct answers was high in items that were easy to divide, and the percentage of correct answers was low in items that were difficult to divide. When children solved the problems, they were affected by the strategies they could use immediately according to the number presented in the problem, and their learning experiences were also affected.

• The Journal of the Convergence on Culture Technology
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• v.5 no.2
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• pp.123-138
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• 2019

The clinical institution of some dental hygiene students and the degree of practice and performance according to the practice contents are identified, so as to develop clinical practice guidelines and to improve the education of universities and practical institutions. From November 2016 to March 2017, the questionnaire was prepared by self-inclusion after explaining the purpose of research and how to prepare questionnaire to some dental hygiene students. This material has been analyzed using PASW Statistics 18.0. As for the clinical practice content items of basic care and infection control, the frequency of "execution" among practice methods was high, and the distribution rate was high in oral evil face radiation, preventive dentistry, prosthesis, periodontology, orthodontics, and oral internal medicine. The conservation department has conducted various practical methods such as "executing," "observing" and "preparing." Oral surgery showed similar distribution rates, such as "observation," "preparation," and "execution" in the "preparation and cooperation of the feet." In pediatric dentistry, "observation" was the most common practice, and among them, "observation," "preparation," and "execution" were performed in "preparation and cooperation for infantile development." In addition, students with more experience in clinical practice showed statistically significant differences in basic care, oral hygiene, preventative dentistry, conservation, dental dentistry, oral surgery, orthodontics, and oral internal medicine(p<0.05). Most clinical practice shows that it is more observable than performed.It is expected that the goal of clear clinical practice content should be set by grade or number of clinical practice experiences, as well as the practice method that can be performed by the trainees.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.75-94
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• 2019

As the present single-layer repository concept requires too large an area for the site of the repository, a multi-layer repository concept has been suggested to improve the disposal density. The effects of the excavation damaged zone around the multi-layer repository constructed in the deep host rock on the temperature distribution in the repository were analyzed. For the thermal analysis of the multi-layer repository, the hydrothermal model was used to consider the resaturation process occurring in the buffer, backfill and rock. The existence of an excavation damaged zone has a significant effect on the temperature distribution in the repository, and the maximum peak temperatures of double-layer and triple-layer repositories can rise to $7^{\circ}C$ and $12^{\circ}C$, respectively depending on the size of the excavation damaged zone and the degree of decrease of the thermal conductivity. The dominant factor affecting the peak temperature in the multi-layer repository is the decrease of thermal conductivity in the excavation damaged zone, and the excavation damaged zone formed around the deposition hole has more significant effects on the peak temperature than does the excavation damaged zone formed around the disposal tunnel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.460-468
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• 2021

This study investigated the enhanced combustion efficiency of an "air-cooled combustion system" with single F.D. fan, and performed a numerical analysis for the operation and design conditions to increase the combustion efficiency. The combustion efficiency in an actual combustor was compared before and after the structure modification. Numerical analysis for application of a single fan revealed the difficulty of forming a turbulence for circular combustion conditions. This is because the supply ratio of combustion air supplied into 2 flow paths becomes irregular in the combustion furnace due to a change in friction force and pressure in each flow path. Subsequently, two methods of supplying air into the combustion furnace were analyzed numerically to obtain the optimal combustion conditions of an air-cooled combustion system. The first method involved injecting the preheated combustion air after a 180~360 degree rotation from the outer wall, whereas in the second method, the combustion air was injected into the combustion furnace in a tangential direction after primary heat exchange outside the combustion furnace, by applying a rotatable vane structure in the combustion furnace. Results reveal that application of a single F.D. fan to the air injection into a rotatable combustion furnace is desirable for optimization of the combustion conditions for applying a duct structure having a dual cooling wall for the cooling of the outer wall of the combustion furnace, and for maintaining perfect mixing in the combustion furnace. We therefore confirmed enhanced combustion efficiency by comparing the actual combustion efficiency before and after structure modification.

• 한국사회정책
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• v.24 no.2
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• pp.157-179
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• 2017

In Korea, 'spoon class discourse' has attracted public attention in the press and among young people, which reflects that mass awareness that the class status structure is clearly rooted in the society becomes widespread. Although income distribution has been improved since late 2000s, it is interesting that Korean people's subjective perception concerning class mobility and social justice has been worsemed. By using the survey data on people's perception of opportunity inequality, this study finds that Korean people have by and large negative subjective awareness regarding socio-economic opportunity inequality, magnitude of opportunity inequality, and achievement by efforts, and that the degree of the negative perception is greater in accordance with the people's subjective identification. The regression analysis reveals that the social status of respondents and their parents(-), experience of discrimination(+), age(-), and high education of college and above (+) have consistent effect over socio-economic opportunity inequality, magnitude of opportunity inequality, and achievement by efforts with statistical significance. More concretely, as people have lower subjective status identification at the time of parent generation and their own generation, as they have the experience of discriminatory misconduct, and as they are young and highly educated, they have negative or pessimistic perception regarding opportuinity inequality. In addition, it is revealed that the unemployed and non-regular workers have significantly negative perception on socio-economic opportunity inequality, magnitude of opportunity inequality, while negative perception on the magnitude of opportunity inequality and achievement by efforts is noticeable among high and middle income households.

• Smart Media Journal
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• v.9 no.4
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• pp.176-186
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• 2020

The size and shape of crops are diverse, and the growing environment is also different. Therefore, when one uses a drone to spray pesticides, the characteristics of each crop must be considered, and flight conditions such as the flight height and forwarding velocity of the drone should be changed. The droplet flow of pesticides is affected by various flight conditions, and a large change occurs in the sprayed area. As a result, an uneven distribution of liquid may be formed at the wake, and the transport efficiency will be decreased as well as there would be a risk of toxic scatter. Therefore, this paper analyzes the degree of distribution of pesticides to the crops through numerical analysis when pesticide is sprayed onto the selected three crops with different characteristics by using agricultural drones with different flight conditions. On the purpose of establishing a guideline for spraying pesticides using a drone in accordance with the characteristics of crops, this paper compares the amount of pesticides distributed in the crops at the wake of nozzle flow using the figure of merit, and the sum of transported liquid rate divided by the root mean square of the probability density function.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.324-347
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• 2022

Geological information on the Korean Peninsula plays a significant role in science education because it provides a basic knowledge foundation for public use and creates an opportunity to learn about the nature of geology as a historical science. In particular, the Mesozoic Era, when the Korean Peninsula experienced a high degree of tectonic activity, is a pivotal period for understanding the geological history of the Korean Peninsula. This study aimed to analyze whether content regarding the geology of the Mesozoic Era are reliably and consistently presented in the 'Geology of the Korean Peninsula' section of Earth Science II textbooks based on the 2015 revised curriculum. Four textbooks for Earth Science II were analyzed, focusing on the sedimentary strata, tectonic movement, and granites of the Mesozoic Era. The analysis items were terms, periods, and rock distribution areas. The consistency within and among textbooks and of textbooks and scientific knowledge was analyzed for each analysis item. Various inconsistencies were found regarding the geological terms, periods, and rock distribution areas of the Mesozoic Era, and suggestions for its improvement were discussed based on these inconsistencies. It is essential to develop educational materials that are consistent with the latest scientific knowledge through collaboration between the scientific and educational communities.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.365-386
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• 2023

The purpose of this study is to investigate the perception of academic journals and scholarly events published and operated by the four major academic societies in library and information science (Korean Library and Information Science Society, Korean Society for Library and Information Science, Korean Biblia Society for Library and Information Science, and Korea Society for Information Management). An online survey was carried out to know the members' perceptions of journals' quality, number, review process, publication/distribution, readership, practicality, interdisciplinarity, internationalization, and differentiation. In addition, the reasons for participation and non-participation in scholarly events, the degree of achievement of the purpose, differentiation between scholarly events, and ways to revitalize joint academic conferences were examined. A total of 197 members of the four societies completed the survey. The findings showed that the overall quality of the four journals was good, but they still needed to be improved in the review process, publication and distribution, readership, practicality, and internationalization. Strategies to specialize each journal needed to be considered as well. To revitalize scholarly events, large-scale joint academic conferences can be organized to encourage the participation of researchers and practitioners, considering both academic and social aspects of research and practice. This study mainly reported the results of the online survey. Also, it shed light on the suggestions to improve the academic journals and scholarly events in the field of library and information science based on the findings from the case studies of international academic journals and events as well as the group discussions and feedback from the participants at the joint conferenece held in December 2022.

• Journal of the Korea Society of Computer and Information
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• v.28 no.8
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• pp.187-194
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• 2023

Recently, a lot of discussions are underway in the field of introducing new technologies about the rapidly growing metaverse. However, the degree of acceptance of metaverse users at the beginning of the introduction is different from expectations, so research should be conducted for the continuous use of current real users and service success. In this study, we would like to investigate the relationship between four experience factors according to Metaverse's experiential economy theory, and perceived value and intention to continue use. A survey was conducted on metaverse real-life veterans, and 177 questionnaires were finally analyzed. The collected data were empirically analyzed using SPSS 25.0 and AMOS 21.0. As a result; First, it was found that all the experience factors of the metaverse had a positive effect on the perceived value. Second, all of the experience factors of metaverse were found to have a positive effect on the intention to continue use. Third, perceived value was found to have a positive effect on the intention to continue use. Based on the analysis results, the implications and limitations of this study were presented. Based on the analysis results, metaverse should provide and develop various experience factors differentiated from reality to users. In addition, providing an experience environment and value that metaverse users can perceive will increase users' intention to continue using it.

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1235-1249
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• 2022

This study applied the web crawling technique for extracting big data news on water quality accidents in the water supply system and presented the algorithm in a procedural way to obtain accurate water quality accident news. In addition, in the case of a large-scale water quality accident, development patterns such as accident recognition, accident spread, accident response, and accident resolution appear according to the occurrence of an accident. That is, the analysis of the development of water quality accidents through key keywords and sentiment analysis for each stage was carried out in detail based on case studies, and the meanings were analyzed and derived. The proposed methodology was applied to the larval accident period of Incheon Metropolitan City in 2020 and analyzed. As a result, in a situation where the disclosure of information that directly affects consumers, such as water quality accidents, is restricted, the tone of news articles and media reports about water quality accidents with long-term damage in the event of an accident and the degree of consumer pride clearly change over time. could check This suggests the need to prepare consumer-centered policies to increase consumer positivity, although rapid restoration of facilities is very important for the development of water quality accidents from the supplier's point of view.