• Communications of Mathematical Education
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• v.37 no.4
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• pp.635-652
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• 2023

This study conducts a comprehensive analysis of the curricular progression of the concepts and learning sequences of 'lines', specifically, 'line segments', 'straight lines', and 'rays', at the elementary school level. By examining mathematics curricula and textbooks, spanning from 2nd to 7th and 2007, 2009, 2015, and up to 2022 revised version, the study investigates the timing and methods of introducing these essential geometric concepts. It also explores the sequential delivery of instruction and the key focal points of pedagogy. Through the analysis of shifts in the timing and definitions, it becomes evident that these concepts of lines have predominantly been integrated as integral components of two-dimensional plane figures. This includes their role in defining the sides of polygons and the angles formed by lines. This perspective underscores the importance of providing ample opportunities for students to explore these basic geometric entities. Furthermore, the definitions of line segments, straight lines, and rays, their interrelations with points, and the relationships established between different types of lines significantly influence the development of these core concepts. Lastly, the study emphasizes the significance of introducing fundamental mathematical concepts, such as the notion of straight lines as the shortest distance in line segments and the concept of lines extending infinitely (infiniteness) in straight lines and rays. These ideas serve as foundational elements of mathematical thinking, emphasizing the necessity for students to grasp concretely these concepts through visualization and experiences in their daily surroundings. This progression aligns with a shift towards the comprehension of Euclidean geometry. This research suggests a comprehensive reassessment of how line concepts are introduced and taught, with a particular focus on connecting real-life exploratory experiences to the foundational principles of geometry, thereby enhancing the quality of mathematics education.

• Korean Journal of Culture and Social Issue
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• v.15 no.2
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• pp.251-271
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• 2009

This research measured a concept of mobility which is included objective travel behavior as well as psychological and physical mechanism that influenced travel behavior. And then, this research examined the relation between mobility and the quality of life in elderly drivers. In research 1, to evaluate the reliability and validity of "Mobility Questionnaire(MQ)", we tested "MQ" to 207 drivers aged 20 years and older. In research 2, we examined the mobility level of elderly drivers. Also we investigated the influence that mobility of elderly drivers impacts on their quaility of life. we used "MQ", "Psychological Well-Being Questionnaire(PWBQ)" to 91 drivers aged 65 years and older. To factor analysis, MQ consisted of 'Safe Driving Ability(ADA)', 'Travel Increase(TI)', 'Travel Decrease(TD)', 'Social Activity(SA)', and 'Driving Situational Adaptability(DSA)'. The amount and speed of driving of elderly drivers reduced driving behavior than other drivers. Also, elderly drivers negatively assessed their physical abilities for safe driving and felt a low confidence in specific driving situation. On the other hand, elderly drivers take parts in social activity constructively. A review of the relation of mobility and quality of life showed that mobility of elderly drivers had positive correlation with PWB. Specially, 'ADA', 'SA', and 'DSA' had significant correlations with PWB of elderly drivers. The mobility of elderly drivers had an effect on 'Autonomy', 'Environmental mastery', 'Self-acceptance', and 'Positive relations with others'.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.338-352
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• 2023

As of 2019, Korea's fine dust is the most severe among 38 OECD countries, and in the same year, 「the Framework on Disaster and Safety Management」 was revised to define fine dust as a social disaster. Currently, the government is working to achieve its emission reduction goals by preparing a comprehensive fine dust management plan (2022-2023) consisting of a total of five areas, 42 tasks, and 177 detailed tasks. However, it is necessary to come up with measures in consideration of the various spatial characteristics of the city, not just as a source of emission. Therefore, in this study, the shape of the city was classified using the LCZ (Local Climate Zone) classification system into 17 types by building type and land cover type in Busan, and the average annual PM10 and PM2.5 concentration were mapped using the IDW technique. In addition, Fragstats and Moving Window were used to quantify the LCZ classification system. Finally, correlation analysis and regression analysis were conducted to analyze the relationship between the LCZ classification system and PM10 and PM2.5. As a result, it was confirmed that the type of low height of the building and the type of green space with trees had a positive effect on the concentration of PM10 and PM2.5. Therefore, this study is expected to be used as basic data to establish fine dust reduction policies based on efficient spatial planning.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.788-805
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• 2023

Purpose: This study aimed to verify the impact of Habitat for Humanity Korea's disaster risk reduction intervention on the mental health and satisfaction with life among residents of southern Bangladesh who had constantly suffered from disaster stress due to perennial flooding. Method: The target group was 138 residents who were pre-surveyed in August 2020 and post-surveyed in November 2021. The interventions consisted of individual incremental housing, public facilities for evacuation, and disaster response training for capacity development. The data were analysed using paired sample t-tests for pre-post changes and one-way analysis of variance to identify differences between treatment groups. Result: The results showed significant improvements in residents' depression, anxiety, somatisation and satisfaction with life after the intervention, with significant differences in mental health levels between the intervention treatments. Specifically, relatively higher disaster mitigation effects were found for individual infrastructure improvements and employment facilities compared to disaster response drills. Conclusion: These results demonstrate the positive role of Habitat for Humanity Korea's disaster risk reduction interventions on the mental health recovery of disaster victims and suggest practical approaches that can be applied in disaster risk areas.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.510-516
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• 2021

Recently, the range of utilization and demand for unmanned aerial vehicle (UAV) has been continuously increasing, and research on the construction of a separate operating system for low-altitude UAV is underway through the development of a management system separate from manned aircraft. Since low-altitude UAVs also fly in the airspace, it is essential to establish technical standards and certification systems necessary for the operation of the aircraft, and research on this is also in progress. If the operating standards and certification requirements of the aircraft are presented, a test method to confirm this should also be presented. In particular, the accuracy of small UAV's navigation required during flight is required to be more precise than that of a manned aircraft or a large UAV. It was necessary to calculate a separate navigation error. In this study, we presented a test method for deriving navigation errors that can be applied to UAVs that have difficulty in acquiring long-term operational data, which is different from existing manned aircraft, and conducted verification tests.

• Clean Technology
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• v.29 no.4
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• pp.279-287
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• 2023

Fine dust emitted from coal combustion is classified into filterable particulate matter (FPM) and condensable particulate matter (CPM). CPM is difficult to control with existing air pollution control devices, so research is being conducted to understand the characteristics of CPM. Components constituting condensable particulate matter (CPM) are divided into inorganic and organic components. There are many quantitative analysis results for the ionic components, which account for a significant proportion of the CPM inorganic components, but little is known about the organic components. Thus, there is a need for a quantitative analysis of CPM organic components. In this study, aromatic hydrocarbons (toluene, ethyl benzene, m,p-xylene, and o-xylene) and n-alkanes with 10 to 30 carbon atoms were quantitatively analyzed to understand the organic components of CPM emitted from a lab-scale coal combustor. Of the aromatic hydrocarbons, toluene accounted for 1.03% of the CPM organic components. On the other hand, the contents of ethyl benzene, m,p-xylene, and o-xylene showed low values of 0.11%, 0.18%, and 0.51% on average, respectively. Among the n-alkanes, triacontane (C₃₀) showed a high content of 2.64% and decane (C₁₀) showed a content of 2.05%. The next highest contents were shown with dodecane (C₁₂), tetradecane (C₁₄), and heptacosane (C₂₇), all of which were higher than that of toluene. The n-alkane substances that had detectable concentrations showed higher contents than ethyl benzene, m,p-xylene, and o-xylene except for tetracosane (C₂₄).

• Journal of Music and Human Behavior
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• v.20 no.2
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• pp.1-32
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• 2023

The purpose of this study was to analyze the rationale and format of music therapy interventions with patients receiving hospice or palliative care in Korea. Through this analysis, I examined whether the music intervention used was based on a valid rationale and represented the professionalism expected of today's music therapy interventions. A total of 12 studies that met the selection criteria were identified, and the overall characteristics of each study and its format were analyzed. As a result of the analysis, it was confirmed that the rationale for each study and its format were influenced by the author's research field. The analysis also showed that the research on music-based interventions in hospice or palliative care settings was insufficient and involved a mix of professional and nonprofessional interventions. The results of this study suggest that importance of researchers possessing professional competence which requires offering a clear justification for their choice of interventions, music, and instruments. Additionally, these results emphasize the need for further development of evidence-based music therapy approaches in hospice and palliative care settings as the role of music in supporting patients in these environments has gained increasing recognition and validation.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.889-897
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• 2023

This study attempted to examine how participation in a cooperative learning extracurricular program affects the improvement of college students' self-directed learning abilities. In order to operate a cooperative learning extracurricular program, students were recruited voluntarily through the school system. A total of 128 students were selected. They formed groups according to the number of participants and participated in the cooperative learning extracurricular program for 9 weeks. Before the program was implemented and after the program was terminated, a survey was conducted on the self-directed learning ability of participating students through a questionnaire. The effectiveness of the program was examined through pre-post tests of the experimental group. The results are as follow. First, the self-directed learning ability scores of students who participated in the cooperative learning extracurricular program significantly improved. Second, in order to closely analyze self-directed learning ability, the sub-elements of self-directed learning ability were examined, and the scores of self-awareness and learning strategy, which are sub-elements of self-directed learning ability, were found to have significantly increased. However, although scores for learning motivation and learning situations improved, the levels were not found to be statistically significant. Based on these results, we presented discussions for improving college students' self-directed learning ability and ways to revitalize cooperative learning in universities.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.236-244
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• 2023

The purpose of this study was to examine the economic feasibility of providing services according to the nationwide expansion of early warning services. The net present value method, one of the cost-benefit analysis methods, was applied to the analysis. As a benefit item that constituted the net present value, the damage reduction amount using crop insurance data and the willingness to pay for the use of early warning services were used. The cost items included system construction and maintenance costs, and text transmission costs. As a result of the analysis, it was found that the nationwide expansion of early warning services had economic feasibility, and its economic effect varied depending on the level of text message use (10 % to 40 %, 10 %p interval) of participating farmers. In the future, the economic effect of early warning services is expected to increase further due to the increase in the number of farmers participating in early warning services and the increase in crop damage caused by climate change. It is necessary to further enhance the economic effect of early warning services by actively utilizing information delivery means through apps or the web as well as text messages.

• Phonetics and Speech Sciences
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• v.15 no.3
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• pp.27-35
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• 2023

This study aimed to investigate the effect of Chinese on the production of Korean rhythm. Korean and Chinese are typologically classified into different rhythmic categories; because of this, the phonological properties of Korean and Chinese are similar and different at the same time. As a result, Chinese can exert both positive and negative influences on the realization of Korean rhythm. To investigate the influence of the rhythm of the native language of L2 learners on their target language, we conducted an acoustic analysis using acoustic metrics like of the speech of 5 Korean native speakers and 10 advanced Chinese Korean learners. The analyzed material is a short paragraph of five sentences containing a variety of syllable structures. The results showed that KS and CS rhythms are similar in %V, VarcoV, and nPVI_S. However, CS, unlike KS, showed characteristics closer to those of a stress-timed language in the values of %V and VarcoV. There was also a significant difference in nPVI_V values. These results demonstrate a negative influence of the native language in the realization of Korean rhythm. This can be attributed to the fact that all vowels in Chinese sentence are not pronounced with the same emphasis due to neutral tone. In this sense, this study allowed us to observe influences of L1 on L2 production of rhythm.