• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.734-744
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• 2011

The purpose of this study was to identify middle school students' mental models on plate tectonics and to compare the mental models of verbal-learning-style students with those of visual-learning-style students. 94 student participants in 9th grade were requested to draw and explain three topics; generation of magma, the formation of the mountain range and the interior of the Earth. The criterions for analyzing the mental models are derived from the data of the drawing task. The research results were as follows: The mental models on the generation of magma were classified as 'unstable model,' 'partial casual model,' 'causal model,' and 'conceptual model.' On the other hand, the mental models on the interior of the Earth were classified as 'static unstable model,' 'dynamic unstable model,' and 'conceptual model.' Students holding 'unstable model' were unable to relate the plate collision and the magma generation. They showed a variety of alternative conceptions of study areas, such as 'magma is generated from the core' and 'the mountain is formed by rising of the plates themselves.' Also, visual-learning-style students showed higher proportion of conceptual models and lower proportion of unstable mental models than verbal-learning-style students on three topics. The findings revealed that the students tend to have different concepts on the plate tectonics depending on their learning style.

• Journal of The Korean Association For Science Education
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• v.34 no.3
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• pp.235-246
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• 2014

This study aims to explore how in-service science teachers adopt newly developed 'Science' focusing on the fusion of science based on 'the diffusion of innovation' model. For this study, we have explored five variables (i.e., perception of need, perception of support, innovativeness, perceived usefulness, self-efficacy of teaching, and intention to adopt) based on literature review and developed survey items to measure the level of five variables that in-service science teachers perceive. In addition, the path model of six variables explaining how in-service science teachers adopt an innovation was hypothesized by the literature review. A total of 349 in-service science teachers have participated in this survey study. First of all, results have illustrated that the levels of six variables have not significantly associated with in-service science teachers' teaching experiences, participation in professional development programs on 'Science' curriculum, and majors. In addition, the statistically acceptable model fit indices have illustrated that path model has been statistically valid to explain how in-service science teachers adopt newly developed 'Science' focusing on the fusion of science. The results have also illustrated that 'perception of support', 'perceived usefulness', and 'self-efficacy of teaching' exhibited strong mediating effects between other variables. For the successful establishment of newly developed curricula, textbook, or policies in science education in school, the level of teachers' intention to adopt innovations should be enhanced. This study will be useful for the development of new science teacher professional development programs to promote the level of teachers' intention to adopt innovations.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.324-333
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• 2006

This study was designed to investigate the effect of bone demineralization and tibia lead on blood lead in retired lead workers. Two hundred thirty five(126 females and 109 males) retired lead workers who worked in 4 different lead factories and 101 non-occupationally lead exposed subjects(51 females and 51 males) were recruited from March 2004 to October 2004. Bone mineral density(BMD) was measured at left calcaneous bone area by broadband ultrasound attenuation(BUA) method with QUS-2(Metra Biosystems Inc, USA). The BUA value transformed into T-score by WHO standard conversion criteria. Tibia bone lead was measured for skeletal bone lead with K-xray fluorescence(K-XRF) and blood lead was analyzed with flameless atomic spectrophotometer. Hemoglobin, hematocrit, serum calcium and iron were also analyzed. In addition, information for smoking and drinking status and basic personal data such as age, gender and lead exposure were also collected using questionnaire inquiry. Blood lead was correlated with tibia lead (r=0.664) and these two variables were negatively correlated with BMD in bivariate analysis. BMD showed significant main effect on the change of blood lead independent to tibia lead without any effect modification of age or gender; the one T-score unit decrease of mineral bone density made $0.43{\mu}g/dl$ increase of blood lead. On the other hand, tibia lead showed effect modification with gender on blood lead; the slope of tibia lead on blood lead in male was steeper than in female and crossed at around zero of tibia lead. In the multiple regression analysis of blood lead and tibia lead on BMD after adjustment of related covariates, only blood lead showed statistically significant effect on BMD. This study confirmed that BMD and blood lead were significantly associated. To verify the causal association of BMD on blood lead and vice versa, further longitudinal studies are needed.

• Journal of Korea Water Resources Association
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• v.40 no.4
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• pp.299-311
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• 2007

Climatic abnormal phenomena involving El Nino and La Nina have been frequently reported in recent decades. The interannual climate variability represented by El Nino-Southern Oscillation (ENSO) is sometimes investigated to account for the climatic abnormal phenomena around the world. Although many hydroclimatologists have studied the impact of ENSO on regional precipitation and streamflow, however, there are still many difficulties in finding the dominant causal relationship between them. This relationship is very useful in making hydrological forecasting models for water resources management. In this study, the seasonal relationships between ENSO and hydrologic variables were investigated in Korea. As an ENSO indicator, Southern Oscillation Index (SOI) was used. Monthly precipitation, monthly mean temperature, and monthly dam inflow data were used after being transformed to the standardized normal index. Seasonal relationships between ENSO and hydrologic variables were investigated based on the exceedance probability and distribution of hydrologic variables conditioned on the ENSO episode. The results from the analysis of this study showed that the warm ENSO episode affects increases in precipitation and temperature, and the cold ENSO episode is related with decreases in precipitation and temperature in Korea. However, in some regions, the local relationships do not correspond with the general seasonal relationship.

• Journal of Korea Water Resources Association
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• v.45 no.5
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• pp.445-454
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• 2012

The present study aims to investigate the long-term channel morphological changes derived from channelization, embankment and levee construction works in unregulated fluvial channel of the Jiseock River. Analyses of aerial photographs taken past (Year 1966) and recent (Year 2002) showed the temporally remarkable changes in channel planform such as channel shape, bar migration, vegetation encroachment in bar. During the period, the natural single threading changed into braided types together with decreasing sinuosity by 9.2%, increasing vegetation occupied bar ranged 97% of total bars area. Because such channel morphological changes are closely similar to those in dam downstream channels, we assume that both/either flow regime alteration and/or sediment transport discontinuity may be critical for the fixed channel and spread of vegetated bars even in unregulated river without dam reservoir upstream. We found more reduced frequency and magnitude of flooding water level comparing with past, but no significant alteration of inter annual water level variation. Bed material has been coarsened by 4~5 times and the riverbed has been degraded in overall channel but aggraded locally in conjunction reach of tributaries. The results indicates that reduced sediment dynamics in fluvial channel which derived by bed material coarsening, river bed degradation and unbalanced sediment transport capacity between tributary and mainstem can be a causal factor to trigger channel morphological changes even in unregulated rivers.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.406-417
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• 2011

The purpose of this paper is to examine the effects of computer/internet game play on depression and life satisfaction via perceived self-control among older adults in Korea. Data were collected from a survey of 237 community-dwelling older adults (age${\geq}$65) who reported internet users. A path analysis was used to examine the causal relationship among the main constructs. Results showed that the computer/internet game play had positive effects on perceived self-control. Perceived self-control was found to decrease depression and improve life satisfaction among older adults. Additional analysis indicated that the computer/internet game play in older adults did not directly affect mental health (depression and life satisfaction) but indirectly affected it via perceived self-control. Furthermore, perceived self-control had greater effects on depression than on life satisfaction. These findings have crucial implications in that perceived sense of self-control needs to be seriously considered when we develop mental health games for older adults.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.404-419
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• 2010

The purpose of this study is to investigate the causal relationship between cabin attendants' job stress level and job satisfaction, organization commitment and turnover intention in the airline service industry. The study was done by conducting a questionnaire research. 215 questionnaires were distributed to cabin attendants of airlines, and 198 questionnaires of which are utilized for data analysis. The collected questionnaires were analyzed using spsswin 12.0 and Amos 5.0 statistical package for the empirical and statistical analysis. The conclusions were as follows: Firstly, cabin attendants' job stress level had significant negative impact on job satisfaction, but the organization commitment seemed to have a positive impact on overall job satisfaction level. Secondly, job stress didn't affect cabin attendants' organization commitment. The result of the study indicates that there needs to be various way implemented by airline management to dissolve the airline's cabin attendant's overall job stress, in order for the attendants to be satisfied with their job and consequently preventing a high turnover rate in the cabin attendant crew. Finally, the limitations of the study and directions for the future research are presented.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.559-566
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• 2017

Despite the government operating various preventive programs to ward off accidents and diseases on business sites, diseases rates are not decreasing, unlike accident rates. In many cases, diseases caused by work have a latent period before symptoms appear or progress over a longer term, making it difficult for workers to prove the causal relation between their work and the diseases. Moreover, data related to the business site are mostly owned by the employer. Even if the employee has access to parts of such data, his lack of medical expertise limits his ability to identify the characteristics of the diseases and how it appears. In August, 2017 the Supreme Court did an about-face with its ruling on the case involving diseases caused by exposure to harmful substances in work environments, by easing the burden of proof on the employees. As such, this study focuses on the case to analyze cases involving diseases that have occurred in work environments and present their implications. In doing so, the study seeks to provide a basic set of data that can help secure the employees' labor rights and rights to health by complementing the current law in relation to recognizing industrial incidents caused by rare diseases and making work environments safer for employees.

• The Journal of the Korea Contents Association
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• v.10 no.8
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• pp.407-416
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• 2010

The purpose of this study was to examine the relationship among women's leisure dance participation, physical image and self-esteem. The subjects in this study were 300 female adults who were selected by cluster sampling from the population that consisted of women who were in their 20s to 50s. In the population, some women got leisure dance at fitness clubs, sport lovers' clubs and dance academies in Seoul and Gyeoggn Province as of 2009, and the others didn't. As for the reliability of the questionnaires used in the study, the Cronbach alpha coefficient of the questionnaires was above .70. The major statistical methods utilized in this study were Frequencies, reliability factor analysis, analysis covariate, regression analysis and path analysis. The findings of the study were as follows: First, the women who got leisuer dance evaluated their own physical image and self-esteem more favorably than the others who didn't. Second, the length of participation affected the body shape, satisfaction level and flexibility, and the intensity of participation impacted on the body shape and muscular power. Third, the length of participation had an impact on self-esteem, and the frequency of participation exerted a negative influence on that. Fourth, the degree of participation had a causal impact on physical image and self-esteem. In other words, the degree of getting leisure dance affected self-esteem in a firsthand manner and exerted a secondhand influence on that through physical image as well. The findings of the study suggested that physical image was one of major parameters to link participation in rhythmic exercise and self-esteem.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.212-226
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• 2013

In this paper, I tried to analyze objectively the structural relation among market directivity, study directivity, and achievement of organization which are intended to equip competitive power of social welfare organization on the social service market centrally formed by the voucher business. Data collection objectives is consist of 7 metropolitan cities social welfare organizations, performing voucher businesses of the Ministry of Health and Welfare, and data is secured from 203 institutions. Some basic technological statistics and regression analysis employing structural equation was used for analysing data. Analyzed result, the structural relation among market directivity and study directivity and organizational performance is appeared meaningfully according to the fact that goodness of fit coefficients is TLI = .86, CFI = .89, RMSEA = .02. With respect to achievement of organization, market directivity and study directivity are all confirmed as positively influenced. The results of analysis about whether market directivity and study directivity for achievement of organization is direct effect or indirect effect shows that market directivity and study directivity are all influenced both directly to organizational performance, and as parameter. By the results of this research, social welfare organizations performing voucher business are to have practical implication requiring organization learning needed collecting and sharing the relevant information and organizational response toward voucher social service market.