• Journal of Korean Society for Atmospheric Environment
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• v.29 no.3
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• pp.275-286
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• 2013

It is well known that exposure to high level of PM (particulate matter) can adversely affect human health. However, little is known about health burden of PM considering the relationship, exposed level of PM, and health level in local communities. And, there is scarcely methodical assessment of uncertainty for application to policies of these assessment results. The scope of this study is divided into two parts: firstly to estimate the death burden of PM10 (particulate matter less then $10{\mu}m$ in diameter) in Seoul metropolitan region, and secondly to evaluate potential uncertainties in these estimates. To estimate the death burden of PM10 in Seoul metropolitan region from 2005~2010, we firstly assessed the relationship between daily mean PM10 and daily death counts in Seoul from 2000~2010, and calculated the death burden of PM10 using BenMAP (Environmental Benefits Mapping and Analysis Program). After that, we identified and characterized uncertainties to substantially influence the results of death burden. The daily mortality risk was increased 1.000227 times (p-value/0.001) associated with $1{\mu}g/m^3$ increase of daily mean PM10 for all ages population, Seoul. And, death burdens of PM10 in Seoul metropolitan region were estimated from 5.51 in 2005 to 5.12 in 2010 per 100,000 people. Finally, we categorized context, model, and input uncertainty and characterized these uncertainties in three dimensions (i.e. location, level, and nature) using uncertainty typology. In our study, we argue that uncertainties need to be identified, assessed, reported and interpreted in order for assessment results to adequately support decision making, such as the establishment of air quality standards based on health burden of air quality.

• Journal of The Korean Association For Science Education
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• v.40 no.4
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• pp.375-383
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• 2020

In this study, we investigated the effects of the multiple representation-based learning strategies using augmented reality in terms of students' conceptual understanding, achievement, and enjoyment of science lessons. 136 8^th-grade students in a coed middle school were randomly assigned to the treatment and the control group. The students learned the concept of the particulate nature of matter related to the properties of substances for four class periods. The multiple representation-based learning strategies designed to facilitate the connecting and integrating representations provided from augmented reality were developed and administered to the students of the treatment group. Results of two-way ANCOVA revealed that the scores of a conceptions test and enjoyment of science lessons test of the treatment group were significantly higher than those of the control group, regardless of their prior science achievement. In a conceptions test, there was a significant difference in the concept of preservation of particles. However, the difference was not statistically significant in the concept of distribution and motion of particles. In terms of an achievement test, there was a significant interaction effect by their prior science achievement. The scores of low-level students were significantly improved, but the effects were not significant to high-level students. On the bases of the results, educational implications for effective teaching and learning using augmented reality are discussed.

• Journal of The Korean Association For Science Education
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• v.30 no.1
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• pp.42-53
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• 2010

Identifying students' misconceptions by teachers is the primary step in using constructivist teaching strategies. We investigated how secondary science teachers were aware of students' misconceptions about the particulate nature of matter and analyzed the total number of differences of predicted misconceptions by their background variables. We also investigated how they addressed students' misconceptions in their instruction, and how necessary they thought it was to identify students' misconceptions for teaching science concepts. A survey was administered to 87 science teachers at 28 middle schools in Seoul. Teachers' predictions were compared with the misconceptions of 240 seventh-grade students. The teachers, as a group, identified almost all the misconceptions held by the students. However, they were unable to predict which types of misconceptions were more frequent. The total number of misconceptions predicted by the teachers who had careers of less than 10 years, possessed Master's degrees, or majored in chemical education was significantly higher. Although most teachers stated that knowing students' misconceptions was needed for their instruction, they rarely and simply addressed them in their instructions. Many techers faced misconceptions in classroom activities, and only few teachers found them through publications relating to students' misconceptions, teacher preparation courses and/or in-service training programs. Educational implications are discussed.

• Journal of Korean Elementary Science Education
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• v.37 no.1
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• pp.39-53
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• 2018

The purpose of this study was to investigate the conceptual structure of subjects related to matter having pre-service elementary school teachers by applying semantic network analysis (SNA). The analyzed concepts in the subjects of matter were 6 words such as 'atom', 'molecule', 'ion', 'electron', 'matter' and 'particle'. The results of SNA of the concepts are as follows : 1. In the semantic network of 'atom', words having a high betweenness centrality were linked with the words based on both the scientific context and the everyday context. 2. The network of 'molecule' was analyzed to be more organized than the network of the 'atom'. 3. In the network of 'ion', the group of words of the scientific context was distinguished from the group of words of the everyday context. 4. The network of 'electron' was analyzed to be more oriented on electricity and magnetism in the field of physics. 5. In the network of 'matter', the words related to compounds were linked with knowledge of history of science. 6. The network of 'particle' was not structured with words based on particulate nature of matter.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.2
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• pp.171-174
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• 1997

To provide better insights into the factors and processes regulating the geochemical behavior of airborne lead (Pb), we have investigated several important aspects of its distribution characteristics using the data collected from the Kyung Hee University-Suwon Campus during 1989 through 1994. Although the Pb data in the area reflected the effects of many anthropogenic activities ongoing in the area, the data were quite useful to assess the geochemical facets affecting the temporal distributions of lead as well as particulate matter (PM). The analysis of these data indicated that the Pb patterns were characteristic of enriched Pb levels during odd-numbered years relative to even-numbered years, while those of PM were exhibiting pronouncingly different patterns. Despite many similarities and differences found between year-to-year distribution patterns, of Pb data, it was possible to discuss the facts associated with relatively high concentrations in the years 1991 and 1993 via normalization of Pb against PM data. According to this procedure, we were able to conclude that relative enrichment in Pb levels during 1991 was due to enhanced input of PM, while that of the year 1993 came from more chemically-oriented processes such as active adsorptive scavenging of Pb onto the PM surface. Based on our comparative analysis of the size-fractionated PM and Pb data sets, we propse that two distinctive mechanisms that are both of phyical (1991) and chemical nature (1993) exerted controls over the observed distribution patterns of airborne Pb in the atmosphere of Suwon.

• Journal of Environmental Impact Assessment
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• v.28 no.5
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• pp.440-456
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• 2019

The controversy of the risk perception related to particulate matters becomes significant. Therefore, in order to understand the nature of the particulate matters, we gathered articles and comments in on-line community related to bicycling which is affected by exposure of the particulate matters. As a result, firstly, the government - led particulate matter policy was strengthened and segmented every period, butthe risk perception related to particulate matters in the bicycle community has become active and serious. Second, as a result of analyzing the perception change of outdoor activities related to particulate matters, bicycle users in community showed a tendency of outdoor activity depending on the degree of particulate matters ratherthan the weather. In addition, the level of the risk perception related to particulate matters has been moved from fears of serious threat in daily life and health, combined with the disregard of domestic particulate matter levels or mask performance. Ultimately, these risk perception related to particulate matters have led some of the bicycling that were mainly enjoyed outdoors to the indoor space. However, in comparison with outdoor bicycling enjoyed by various factors such as scenery, people, and weather, the monotonous indoor bicycling was converted into another type of indoor exercise such as fitness and yoga. In summary, it was derived from mistrust of excessive information or policy provided by the government or local governments. It is considered that environmental policy should be implemented after discussion of risk communication that can reduce the gap between public anxiety and concern so as to cope with the risk perception related to particulate matters. Therefore,this study should be provided as an academic basis for the effective communication direction when decision makers establish the policy related to particulate matters.

• Journal of Preventive Medicine and Public Health
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• v.57 no.2
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• pp.185-196
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• 2024

Objectives: Excess mortality associated with long-term exposure to fine particulate matter (PM_2.5) has been documented. However, research on the disease burden following short-term exposure is scarce. We investigated the cause-specific mortality burden of short-term exposure to PM_2.5 by considering the potential non-linear concentration-response relationship in Korea. Methods: Daily cause-specific mortality rates and PM_2.5 exposure levels from 2010 to 2019 were collected for 8 Korean cities and 9 provinces. A generalized additive mixed model was employed to estimate the non-linear relationship between PM_2.5 exposure and cause-specific mortality levels. We assumed no detrimental health effects of PM_2.5 concentrations below 15 ㎍/m³. Overall deaths attributable to short-term PM_2.5 exposure were estimated by summing the daily numbers of excess deaths associated with ambient PM_2.5 exposure. Results: Of the 2 749 704 recorded deaths, 2 453 686 (89.2%) were non-accidental, 591 267 (21.5%) were cardiovascular, and 141 066 (5.1%) were respiratory in nature. A non-linear relationship was observed between all-cause mortality and exposure to PM_2.5 at lag0, whereas linear associations were evident for cause-specific mortalities. Overall, 10 814 all-cause, 7855 non-accidental, 1642 cardiovascular, and 708 respiratory deaths were attributed to short-term exposure to PM_2.5. The estimated number of all-cause excess deaths due to short-term PM_2.5 exposure in 2019 was 1039 (95% confidence interval, 604 to 1472). Conclusions: Our findings indicate an association between short-term PM_2.5 exposure and various mortality rates (all-cause, non-accidental, cardiovascular, and respiratory) in Korea over the period from 2010 to 2019. Consequently, action plans should be developed to reduce deaths attributable to short-term exposure to PM_2.5.

• Journal of The Korean Association For Science Education
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• v.26 no.2
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• pp.191-199
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• 2006

This study investigated the influence of time to draw students' mental models and students' field dependence-independence on learning the particulate nature of matter with multiple representations. Seventh graders (N=295) at two middle schools were assigned to control, after-drawing, and before-drawing groups. The students learned "Boyle's Law" and "Charles's Law" for two class periods. Results revealed that the scores of a test on conceptual understanding for the two drawing groups were significantly higher than those for the control group. However, there was no significant interaction between the instruction and students' field dependence-independence in the scores of the test on conceptual understanding. In 'novelty' on a situational interest test, field independent students in the two drawing groups scored significantly higher than those in the control group. The scores for field independent students in each group were similar, while field dependent students in the before-drawing group scored lower than those in the control and after-drawing groups in 'attention demand' on the situational interest test. It was found that most students positively perceived after-drawing or before-drawing, but field independent students in the before-drawing group were more apprehensive about the activities than those in the after-drawing group.

• Journal of The Korean Association For Science Education
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• v.25 no.4
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• pp.533-540
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• 2005

This study investigated the effects of drawing and writing as methods to assist students in connecting and integrating multiple external representations provided in learning the particulate nature of matter. Seventh graders (N=224) at a coed middle school were assigned to a control group, a drawing group, and a writing group. The students were taught about "Boyle's Law" and "Charles's Law" for two class periods. Students observed macroscopic phenomena through experiments. After this observation, students in the control group learned the topic with both external visual and verbal representations simultaneously. Students in the drawing group drew their mental model from the external verbal representation provided, and then compared their drawing with external visual representation. Students in the writing group wrote their mental model from the external visual representation provided, and then compared their writing to the external verbal representation. The two-way ANCOVA results revealed that the scores of a conception test for the writing group were significantly higher than those for the control group. While the drawing group performed better than the control group, the difference is relatively smaller. There were no significant interactions between the instruction and spatial visualization ability in the scores of the conception test. Most students perceived the writing or drawing activities helpful in understanding the concepts, and a few students responded that the writing or drawing activity was interesting. Educational implications were discussed.

• Journal of Biosystems Engineering
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• v.38 no.3
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• pp.208-214
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• 2013

Purpose: Performances of a tractor diesel engine fueled by three different animal fats biodiesels were evaluated comparing with light oil tractor in terms of power, fuel consumption rate, exhaust gases, particulate matter amount and field work capacity. Methods: Animal fats based on pig biodiesel were manufactured manually and tested for its engine performance in the tractor diesel engine and fuel adoptability in the field works. Four different fuels, three different content of biodiesel (BD20, BD50, BD100) and light oil, were prepared and tested in the four strokes diesel engine. Power output, fuel consumption rate and exhaust gases of the four fuels in the diesel engine were compared and discussed. Results: Power output of light oil engine was the greatest showing 5.3% difference between light oil and BD100, but 0.37% better power than BD20 engine power. Less exhaust gases of $CO_2$, CO, $NO_X$ and THC were produced from animal fats biodiesel than light oil, which confirmed that biodiesel is environmental friendly fuel. For fuel adoptability in the tractor, biodiesel engine tractor showed its fuel competitiveness comparing with light oil for tractor works in the faddy field. Conclusions: With four different fuel types of animal-fats biodiesel, performances of a four cylinder diesel engine for tractor were evaluated in terms of power, exhaust gases, particulate matters (PM) and field work capacity. No significant differences observed in the engine performances including power output and exhaust gases emission rate. No significant power difference observed between the various fuels including light oil on the engine running, however, amounts of noxious exhaust gases including $CO_2$ and $NO_X$ decreased as biodiesel content increased in the fuels. Field performances of animal-fats biodiesel tractor were investigated by conducting plowing and rotary operation in the field. Tilling and rotary performance of light oil tractor and BD20 tractor in the field were compared, in which about 10% travelling speed difference on both operations were monitored that showed light oil tractor was superior to BD20 tractor by 10%. Animal-fats can be an alternative fuel source replacing light oil for agricultural machinery and an environmental friendly fuel to nature.