• Educational Technology International
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• v.14 no.1
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• pp.75-108
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• 2013

The purpose of this study is to find a way to improve digital textbooks for self-regulated learning by applying cognitive scaffolding designs to an elementary math digital textbook and examining the effectiveness of the system. Hence this study was conducted in two steps. First, a framework for scaffolding design was devised by examining the problems and difficulties students encounter when using a mathematics digital textbook. Second, after the digital textbook was revised by applying the scaffolding design frameworks, the effectiveness of the scaffolding framework was examined by comparing students' achievement levels in an experimental group and that of students in a control group. Seventy fifth-graders participated in this study. Students were divided into two groups: an experimental group and a control group. The students in the experimental group studied with the revised version of the digital textbook and the students in the control group studied with the original version of the digital textbook. The students received a pretest before the experiment. After the experiment, they took an achievement test and completed a usability questionnaire. The data were analyzed by ANCOVA with the SPSS Windows version. The results revealed that the students who used the revised program (to which design strategies for scaffolding were applied) showed higher levels of achievement than those who used the original version. In addition, students in the experimental group generally showed higher scores on the usability survey, which consisted of four sub-categories such as 'effectiveness', 'efficiency', 'satisfaction', and 'learnability'. There was a statistically significant effect on 'efficiency'. These results implied that scaffolding strategies were effective for mathematics learning through the use of an elementary digital textbook.

• Journal of The Korean Association For Science Education
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• v.27 no.6
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• pp.529-545
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• 2007

Questioning forms an integral part of most strategies for effective teaching when the class consists of difficult content. Science including chemistry is usually content-rich, but difficult to understand without supporting lab experiments, subsidiary visual materials and model kits. Engaging the attention and interest of students in such a subject, therefore, is the key to the success of a daily lesson in the classroom. However, generating meaningful questions requires a certain level of information and metacognitive skills on the part of the teacher. The purpose of this study was to find out the framework of effective teachers' questioning with a large group in chemistry class: how teachers used questioning to engage their students in such a big class, to identify a variety of forms of feedback provided by students and to develop a model of question-inducing strategies. We investigated the teachers' recognition of their questioning and the students' recognition of teachers' questioning by surveying over 82 teachers and 434 students in Korea. The survey findings show that the questionnaire can be categorized into four elements: the theme of the teachers' questions (T), students' inquiries (I), methods of teachers' questioning (M) and encouragement of students (E). These elements can be analyzed and sub-categorized to find out which elements are effective in good questioning, even though the elements are interwoven tetrahedrally.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.2
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• pp.154-166
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• 2009

In this study, 1-hour integrated $PM_{2.5}$ mass and chemical composition concentrations were monitored at the St. Louis-Midwest Supersite in Illinois. Time-resolved samples were collected one week in each of June 2001 (22 June to 28 June), November 2001 (7 November to 13 November), and March 2002 (19 March to 25 March). A total of 427 samples were collected by CAMM (continuous ambient mass monitor) and 15 compounds were analyzed by AAS, PILS (particle-into-liquid sampler), and TOT (thermal optical transmittance) method. PMF was applied to identify the sources and apportion the $PM_{2.5}$ mass to each source for highly time resolved data. In addition, the nonparametric regression (NPR) was applied to identify the predominant directions of local sources relative to wind direction. Also, this study performed compare the NPR analysis and location of actual local point sources at the St. Louis area. The PMF modeling identified nine sources and the average mass was apportioned to gasoline vehicle, road dust, zinc smelter, copper production, secondary sulfate, diesel emission, secondary nitrate, iron+steel, and lead smelter, respectively. These results suggested that this study results will be help for $PM_{2.5}$ source apportionment studies at similar metropolitan area, establish $PM_{2.5}$ standard, and establish effective emissions reduction strategies in Korea.

• Journal of the Korean Society of School Health
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• v.32 no.3
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• pp.165-174
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• 2019

Purpose: The purpose of this study was to identify the influence of eHealth literacy on health promoting behaviors, thereby providing basic data for the development of interventions for health promoting behaviors among university students. Methods: Data were collected from 242 university students aged 19 and over in a university located in K province in South Korea. Participants responded to structured questionnaires in September 2018. eHealth literacy and health promoting behaviors were measured by eHealth Litaracy (EHL) and a translated version of the Health Promoting Lifestyle Profile (HPLP-II), respectively. The correlation between eHealth literacy and health promoting behaviors were analyzed using Pearson's correlation, and multiple regression analysis was carried out to examine the influence of eHealth literacy on health promoting behaviors. Results: The participants had a moderate level of eHealth literacy with the greatest score recorded in the sub-domain of functional eHealth literacy and the lowest in the sub-domain of critical eHealth literacy. Female students and students who majored in healthcare had higher levels of eHealth literacy than male students and those with non-healthcare majors. The degree of health promoting behaviors was moderate or lower with the highest score being in the sub-domain of interpersonal support and the lowest in the sub-domain of health responsibility. Health promoting behaviors had significant relationships with eHealth literacy, exercise hours, subjective health status, and health concerns. Multiple regression analyses revealed that the participants engaged more in health promoting behaviors when they had greater eHealth literacy (β=.18, p<.001), interest in their own health (β=.33, p<.001), exercise hours (β=.18~.23, p<.001), and subjective health status (β=.17~.18, p=.007~.031). Conclusion: In order to facilitate health promoting behaviors of university students, interventions for health promoting behaviors need to be developed including strategies to improve competencies relevant to critical eHealth literacy and to increase exercise hours.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.969-975
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• 2010

Estimating the organic matter loadings from individual treated sewage has become important for establishment of effective management strategies to control refractory organic matter (R-OM) in watersheds. For this study, regression equations were constructed using treated sewage data to convert the chemical oxygen demand (COD) concentrations, which are mostly available from open database, into total organic carbon (TOC) and R-OM concentrations. Effluent samples were collected from five major sewage treatment plants (STPs) located upstream of the lake Paldang. Variations in the OM concentrations were not associated with either the location of the STP or the sampling season. The effluent investigated were characterized by higher ratio of R-OM with respect to biodegradable organic matter (B-OM) and higher presence of dissolved organic matters (DOM) versus particulate organic matter (POM). Compared to $COD_{Mn}$, $COD_{Cr}$ exhibited higher oxidation efficiencies and greater variations in the concentrations. The concentrations of $COD_{Mn}$ were positively correlated with dissolved organic carbon (DOC), total organic carbon (TOC), and R-OM concentrations. There was nearly no seasonal and annual variation in the regression equations between $COD_{Mn}$ and TOC or R-OM concentrations. The constructed regression equations for TOC and R-OM were $0.650({\pm}0.071){\times}COD_{Mn}+1.426({\pm}0.575)$ and $0.340({\pm}0.083){\times}COD_{Mn}+2.054({\pm}0.670)$, respectively. The established equations are expected to contribute to estimating OM loadings from the STPs into the lake Paldang and also to compensating for the deficiency of the data for effluent OM concentrations in STP.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.189-195
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• 2008

We developed emission factors for alternative fuels used in cement industries in Korea and also estimated reduction in emissions of greenhouse gas (GHG) by the use of alternative fuels. Emission factors for GHG of waste tire, waste plastic, waste oil and RDF were estimated to be about 89, 78, 77 and 95 ton $CO_2$/TJ respectively. When compared with previous studies, most of the results showed similar trends. The calorific value estimation and elemental analysis for energy source were implemented in order to estimate the exact emission factors and the reduction of GHG emissions using alternative fuel. In the case of 'A' company, $CO_2$ emission from alternative fuels was about 4% lower than that of bituminous coal only. Also in case of company 'B', $CO_2$ emission from alternative fuels was about 1.4% lower than that of only bituminous coal. In Germany and Japan, alternative fuel is not regarded to be fuel consumption in cement industry. When applying this rule, the emission reductions were about 4.3% for company 'A' and 6.3% for company 'B'. The results of this study may be considered as a useful information for developing strategies in reducing GHG emissions.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.893-902
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• 2015

Various Lactobacillus reuteri strains were screened for the ability to convert glycerol to 1,3-propanediol (1,3-PDO) in a glycerol-glucose co-fermentation. Only L. reuteri DSM 20016, a well-known probiotic, was able to efficiently carry out this bioconversion. Several process strategies were employed to improve this process. Co²⁺ addition to the fermentation medium, led to a high product titer (46 g/l) of 1,3-PDO and to improved biomass synthesis. L. reuteri DSM 20016 produced also ca. 3 µg/g of cell dry weight of vitamin B₁₂, conferring an economic value to the biomass produced in the process. Incidentally, we found that L. reuteri displays the highest resistance to Co²⁺ ions ever reported for a microorganism. Two waste materials (crude glycerol from biodiesel industry and spruce hydrolysate from paper industry) alone or in combination were used as feedstocks for the production of 1,3-PDO by L. reuteri DSM 20016. Crude glycerol was efficiently converted into 1,3-PDO although with a lower titer than pure glycerol (33.3 vs. 40.7 g/l). Compared with the fermentation carried out with pure substrates, the 1,3-PDO produced was significantly lower (40.7 vs. 24.2 g/l) using cellulosic hydrolysate and crude glycerol, but strong increases of the maximal biomass produced (2.9 vs 4.3 g/l CDW) and of the glucose consumption rate were found. The results of this study lay the foundation for further investigations to exploit the biotechnological potential of L. reuteri DSM 20016 to produce 1,3-PDO and vitamin B₁₂ using industry byproducts.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.41-49
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• 2011

The power plants are one of the GHG major source among the sectors of fossil fuel combustion, therefore information of its emission factors is very essential to the establishing control strategies for the greenhouse gas emissions. The $CH_4$ and $N_2O$ concentration from power plants were measured using GC-FID and GC-ECD. The results showed that $CH_4$ emission factor was 0.33 kg/TJ and $N_2O$ emission factor was 0.88 kg/TJ. The $CH_4$ and $N_2O$ emission factors developed in this study were compared with those for IPCC default value and other countries emission factors. The results showed that $CH_4$ emission factor was lower than IPCC default value and Finnish emission factor, but higher than Japanese emission factor. $N_2O$ emission factor was higher Japanese emission factor and IPCC default emission factor however lower than Finnish emission factor. More research is needed on our own emission factors of various energy-consuming facilities in order to stand on a higher position in international negotiations regarding the treaties on climate changes.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.5
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• pp.687-696
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• 2018

In order to develop effective emission abatement strategies for coal-fired power plants, we analyzed the shutdown effects of coal-fired power plants on $PM_{2.5}$ concentration in June by employing air quality model for the period from 2013 to 2016. WRF (Weather Research and Forecast) and CMAQ(Community Multiscale Air Quality) models were used to quantify the impact of emission reductions on the averaged $PM_{2.5}$ concentrations in June over Chungcheongnam-do area in Korea. The resultant shutdown effects showed that the averaged $PM_{2.5}$ concentration in June decreased by 1.2% in Chungcheongnam-do area and decreased by 2.3% in the area where the surface air pollution measuring stations were located. As a result of this study, it was confirmed that it is possible to analyze policy effects considering the change of meteorology and emission and it is possible to quantitatively estimate the influence at the maximum impact region by utilizing the air quality model. The results of this study are expected to be useful as a basic data for analyzing the effect of $PM_{2.5}$ concentration change according to future emission changes.

• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.31-41
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• 2011

The $LCCO_2$ evaluation programs previously developed in Korea involve limitations in establishing strategies of reducing environmental loads to optimal level in a way to put in materials directly after designing. Therefore, this study has the purpose to extract and propose elements required for the establishment of highly accurate system by counteracting swiftly in a method with high energy efficiency over cost at planning stage. To that end, existing $LCCO_2$ evaluation programs in Korea and abroad were compared and analyzed, and in the planning stage, GEM-21P and Carbon-navigator intended for the establishment of building energy performance improving strategy were selected as the evaluation program for survey. On such basis, after comparison and analysis between $LCCO_2$ calculating methods and system structures of the two programs, elements required for system establishment that can evaluate life-cycle environmental loads of building in planning stage were proposed.