• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.137-140
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• 2003

The flow characteristics of secondary recirculation region in a liquid fuel ramjet combustor are measured using PIV method. The model combustor has two rectangular inlets that form 90 degree angle each other. The tested angles of the air intakes were 30, 45 and 60. Three guide vanes are installed in each rectangular inlet to improve the flow stability. The experiments are performed in the water tunnel test with the same Reynolds number as the case of Mach 0.3 at the inlet. PIV software is developed to measure the characteristics of the flow field in the combustor. The accuracy of the developed PIV program is verified with rotating disk experiment and standard data. The experimental results show that the secondary recirculation flow occurred at the front junction of inlet main stream and combustorchamber. The size of secondary recirculation regions are increased with increasing air inlet angles. Since the performanceof combustor is very dependant on not only the main recirculation in the dome region but also the secondary recirculation flow in a junction region, the optimal angle of the air intakes should consider the both recirculation size as a frame holder.

• Journal of Distribution Science
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• v.12 no.7
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• pp.45-51
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• 2014

Purpose - This study aims to explore the success of Lotte Mart in the global market, as well as examining the factors related to its entry methods. Research design, data, and methodology - This study analyzed the differences between Lotte Mart and E-mart in terms of their market entry methods, based on references and secondary data. This study is based on qualitative research that analyzes actual cases. Based on the results, this study analyzed and discussed actual cases based on references and secondary data, including newspaper interviews on Lotte Mart. Results - Lotte Mart succeeded in adapting to local markets it did this by ensuring the use of both mergers and acquisitions (M&As) and greenfield methods. In contrast, E-mart utilized only greenfield methods. Conclusions - The findings of this study may not be generalized to all industries, as only Lotte Mart was examined using the case analysis method. Therefore, the successful market entry modes of various companies should be explored in terms of FDI.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.106-109
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• 2005

The Coanda effect has been used extensively in various aerodynamic applications to improve the system performance. The primary flow in Coanda ejectors is attached to the ejector wall and is expanded inducing a secondary flow. This will probably lead to the mixing of both primary and secondary flows at a down stream section. Very few works have been reported based on the optimization on such devices. The main objective of the present study is to numerically investigate the flow field on a typical Coanda ejector and validate the results with the available experimental data. Many configurations of the Coanda ejector have been analyzed. The effect of various geometric parameters of the device on the expanding mixing layer has also been obtained. The computed data agree fairly well with the experimental data available.

• Journal of Korean Academy of Nursing
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• v.34 no.5
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• pp.881-890
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• 2004

Purpose: The purpose of this study was to explore women caregivers' lived experiences in caring at home for a family member with dementia and to identify conditions that oppress women in the context of family caregiving. Method: This study was conducted within the feminist perspectives using qualitative secondary data. Ten secondary data conveying self reflective contents were selected from the 25 original data obtained in 1999 to 2000. Result: Six themes that emerged from the qualitative thematic content analysis were; androcentric view of family caregiving, undervalued family caregiving by the family members, Self rationalization in the context of family caregiving, family-centric care mechanism, exemplary caring within the family context, and inter-familial relationships among women. Conclusion: The main focus of feminist research is to provide empowerment for the women, research participants and to bring about social change of oppressive constraint through some actions. On the basis of the research findings, therefore, action strategies from feminist perspectives were suggested in some aspects of health care delivery sectors, nursing education and research sectors, and administrative sectors.

• The Journal of Sustainable Design and Educational Environment Research
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• v.2 no.2
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• pp.1-14
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• 2002

The purpose of this study was to develop the expert system based on the artificial neural networks for architectural design phases. The applied building was secondary school focussed in its space-relational-diagram. To implement this system, a data matrix derived from case based database was used as learning pattern, and its output data was lastly evaluated by the educational phase's behavior & activity analysis data. The results of this study were as follows; 1) the needs of educational system for real world spacing can be solved by this expert system based on neural networks. 2) FCM also can be applied for architect's needs. 3) Afterwards, for developing architectural planning & design processes, information technology (for example, internet, odbms, dca and etc.) can be used.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.717-726
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• 2021

Tourism is one of the key economic drivers not only in Vietnam but also in the world. This study explores the awareness and perceptions of key stakeholders such as local residents, tourism businesses, and tourists on sustainable tourism development in the Mekong Delta in Vietnam. Both quantitative and qualitative research approaches have been used with the secondary and primary data to provide insights on the subject. The secondary data is from vast sources, including the governmental department of tourism, statistical departments, annual all-level governmental reports, businesses, and others. The primary data is from the survey by questionnaires with 230 enterprises, 720 local residents, and 670 tourists and from the semi-structured and in-depth interviews conducted with local residents, businesses, tourists, local authorities' officers, and especially with 5 experts who are also stakeholders of Mekong Delta tourism. The results will help the related authorities understand the awareness and perceptions of the key stakeholders and deliver valuable information and a concrete delineated roadmap toward sustainable tourism development of the research settings.

• Child Health Nursing Research
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• v.30 no.1
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• pp.67-74
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• 2024

Purpose: This study aimed to identify the general characteristics and health behaviors of students with non-therapeutic substance use. Methods: This secondary data analysis used data from the 17th Korea Youth Risk Behavior Web-based Survey (2021). Analyses of the 54,848 adolescents used descriptive statisics, the Rao-Scott χ² test, and logistic regression. Results: The risk factors for substance use among students were anxiety, loneliness, living separately from family, suicidal ideation, e-cigarette use, and high stress. Conclusion: The findings help identify the risk factors for non-therapeutic drug use among adolescents. Since South Korea does not have a drug prevention program for its adolescent population, an educational plan based on these findings could help prevent adolescent substance abuse.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.4
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• pp.393-403
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• 2008

In an effort to estimate secondary $PM_{10}$ concentrations and their diurnal variations at different photochemical activities, $PM_{10}$, CO, and $O_3$ concentrations obtained from the ambient air quality network located in Seoul are analyzed for the period from 2000 to 2005. In order to classify the photochemical activities on a daily basis, measured ${\Delta}O_{3,\;max-min}$ (maximum $O_3$-minimum $O_3$) and ${\int}(hv)dt$ which represents accumulated daily insolation, were used to classify each day into three regimes: 1) low photochemical reactivity; ${\Delta}O_{3,\;max-min}\;{\leq}\;40\;ppb$, and ${\int}(hv)dt\;{\leq}\;4000\;W/m^2$, 2) moderate photochemical reactivity; $40\;ppb\;<\;{\Delta}O_{3,\;max-min}\;{\leq}\;60\;ppb$, and $4000\;{\leq}\;{\int}(hv)de\;{\leq}\;6000\;W/m^2$, and 3) high photochemical reactivity; ${\Delta}O_{3,\;max-min}\;>\;60\;ppb$, and ${\int}(hv)dt\;{\geq}\;6000\;W/m^2$. The ratio of ($PM_{10}$/CO) obtained at low photochemical activity regime was used as an index of tracer for the estimation of secondary $PM_{10}$ at higher photochemical activity regimes. The results show that the estimated secondary $PM_{10}$ concentrations for moderate and high photochemical regimes are found to be 18.8% ($10.9\;{\mu}g/m^3$), and 35.0% ($26.2\;{\mu}g/m^3$), respectively. Diurnal variation of secondary $PM_{10}$ for the moderate photochemical regime shows weak but noticeable patterns. However, the highly activated photochemical regime shows strong diurnal variations of secondary $PM_{10}$ concentrations with the maximum value of $35.1\;{\mu}g/m^3$ at 1300LST.

• Journal of The Korean Association For Science Education
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• v.30 no.5
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• pp.636-646
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• 2010

The purpose of this study is to confirm secondary biology teachers' recognition about cell and gene concepts that should be taught in biology according to each school level and to classify the concepts into essential, optional and non-essential ones. We developed a questionnaire in consultation with 5 biology professors after selecting some biological concepts from some data about the recommendations of BSCS, biology, study for the connection with biological contents in each school level. This survey was conducted to biological teachers in secondary schools (146 individuals) from all over Korea for studying the concepts of the cell and gene in elementary and secondary schools. The results of this study revealed the following: The number of essential concepts in the cell and gene domain increases as the school levels go up. Moreover, secondary biology teacher recognized that there must be much more cell and gene concepts that should be taught in elementary and secondary schools compared to those suggested in the science curriculum and BSCS' recommendation.

• Journal of The Korean Association For Science Education
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• v.24 no.6
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• pp.1158-1172
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• 2004

This study searched secondary school students' epistemological views and ontological views about nature and the root causes of such their views. The subjects were 156 secondary school students and data were gathered by the questionnaire developed based on preceding researches. As a result, many secondary school students had epistemological views of unknowable nature. There were various root causes of their epistemological views such as regularity and harmony of nature, predictable and circular natural phenomenon, causation, the relation between human and nature. On the other hand, a lot of secondary school students had ontological view of supernatural nature. Their religious beliefs were very powerful influence their supernatural ontological views. The nature is the object of science and the physical world. Because those views supply science educators basic backgrounds how leaners understand science class, secondary school students' epistemological views and ontological views are precious information. From now on, it is necessary to study relations between students' epistemological views and ontological views and their science class processes.