• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.395-401
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• 2008

Since metallic foam will increase the performance of heat exchanger, it have caused many researcher's attention recently. Our research base on the model that metallic foams applied to heat exchanger. In this case, there is three kind of heat transfer mechanisms, heat conduction in fibers, heat transfer by conduction in fluid phase, and internal heat change between solid and fluid phases. In this paper we study both the hydraulic and thermal aspect performance. Pressure drop along air flow direction will be presented. As thermal aspect, we first discuss the acceptance of applying thermal equilibrium among the two phases. then to calculate the dimensionless temperature profile, the heat transfer coefficient and Nu number in 14 metallic foams(7 Aluminium foams, 7 FeCrAlY foams). All these discussion is based on the same velocity u=2 m/s.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.239-243
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• 2008

In many literatures the researchers pointed out that the using metal foam will significantly enhance the performance of heat exchanger. This paper focuses on theory study of metal foam, including calculation method of properties of foam (permeability ��K, inertial coefficient f, fiber diameter $d_f$, and effective conductivity $k_e$), model of pressure drop and model of heat transfer. Theory analysis on the performance of heat exchanger will be presented here. Finally the optimal material will be obtained from theory calculation.

• Environmental Engineering Research
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• v.14 no.2
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• pp.102-110
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• 2009

Application of artificial intelligence (AI) approaches in eco-environmental modeling has gradually increased for the last decade. Comprehensive understanding and evaluation on the applicability of this approach to eco-environmental modeling are needed. In this study, we reviewed the previous studies that used AI-techniques in eco-environmental modeling. Decision Tree (DT) and Artificial Neural Network (ANN) were found to be major AI algorithms preferred by researchers in ecological and environmental modeling areas. When the effect of the size of training data on model prediction accuracy was explored using the data from the previous studies, the prediction accuracy and the size of training data showed nonlinear correlation, which was best-described by hyperbolic saturation function among the tested nonlinear functions including power and logarithmic functions. The hyperbolic saturation equations were proposed to be used as a guideline for optimizing the size of training data set, which is critically important in designing the field experiments required for training AI-based eco-environmental modeling.

• Journal of IKEEE
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• v.17 no.4
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• pp.505-510
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• 2013

In this paper, a method of estimating hand and elbow movements using electrocorticogram (ECoG) signals is proposed. Using multiple channels, surface electromyogram (EMG) signals and ECoG signals were obtained from patients simultaneously. The estimated movements were those to close and then open the hand and those to bend the elbow inward. The patients were encouraged to perform the movements in accordance with their free will instead of after being induced by external stimuli. Surface EMG signals were used to find movement time points, and ECoG signals were used to estimate the movements. To extract the characteristics of the individual movements, the ECoG signals were divided into a total of six bands (the entire band and the ${\delta}$, ${\Theta}$, ${\alpha}$, ${\beta}$, and ${\gamma}$ bands) to obtain the information entropy, and the maximum likelihood estimation method was used to estimate the movements. The results of the experiment showed the performance averaged 74% when the ECoG of the gamma band was used, which was higher than that when other bands were used, and higher estimation success rates were shown in the gamma band than in other bands. The time of the movements was divided into three time sections based on movement time points, and the "before" section, which included the readiness potential, was compared with the "onset" section. In the "before" section and the "onset" section, estimation success rates were 66% and 65%, respectively, and thus it was determined that the readiness potential could be used.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1824-1828
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• 2016

AcrR, the toxic-compounds-response regulator, regulates motility in microorganisms, presumably to escape from toxic environments. In this study, the genome-wide target genes of AcrR were investigated in a ΔacrR mutant strain by microarray analysis. In the absence of AcrR, the transcription of most flagella/motility genes was highly increased. In addition, flagella formation was increased in this mutant strain. Motility assays revealed that AcrR modulates swimming motility, but not swarming.

• Journal of Korean Home Economics Education Association
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• v.27 no.4
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• pp.141-154
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• 2015

The world has been demanding a green growing world in order to solve serious environmental pollution and resource depletion. This study aims to identify life style factors that drive eco-friendly clothing practices and efficacy in middle school students. Data was collected from 215 middle school students in Daegu, using a self-administered questionnaire in December 2013. Statistical analyses to determine frequency, average, ANOVA, factor analysis, reliability analysis, and regression analysis were performed using SPSS 21 program. The results of factor analysis indicated that eco-friendly clothing practices were classified into purchasing and management, reuse, washing, and recycle, and eco-friendly clothing practices efficacy was sub-grouped into practice confidence, purchasing and management efficacy, and washing and sharing efficacy, and life style consisted of fashion pursuit, environment pursuit, planned purchasing, and economy. Eco-friendly clothing practices and efficacy were significant differences in sex and grade (p<0.05). Eco-friendly clothing practices were significantly affected by the factors of environment pursuit, planned purchasing, economy of life style, and the factors of practice confidence, purchasing and management efficacy, and washing and sharing efficacy of eco-friendly clothing practices efficacy (p<0.05). The planned purchasing factor of life style significantly affected all the factors of eco-friendly clothing practices efficacy. This study suggests that eco-friendly clothing practices education program could account for the life style factors such as fashion pursuit, environment pursuit, planned purchasing, and economy with gender and grade to be effective for middle school students.

• Hwankyungkyoyuk
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• v.24 no.3
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• pp.34-43
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• 2011

Project-based learning is an innovative approach to learning that teaches a multitude of strategies critical for success in the twenty-first century. Students drive their own learning through inquiry activity, as well as work collaboratively to research and create projects that reflect their knowledge. The purpose of this study was to investigate the effects of eco-friendly school project activity which is applied from one of project-based learning approach on learning outcomes of students in ninth-grade environment course in middle school. The participants were given a questionnaire before and after the environmental project activities. In solving the school environment issues themselves, students have practiced invaluable problem solving skills. This study indicates that school students' awareness about the environment has positively changed by experiencing the eco-friendly school project. In addition, this project affects students' variety of environmental awareness. This project could be applied to school environmental education programs and to environment lessons, developmental activities or club activities for a positive impact on students' environmental awareness.

• Carbon letters
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• v.24
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• pp.1-9
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• 2017

We studied the basic properties and fabrication of reduced graphene oxide (rGO) prepared using eco-friendly reduction agents in the graphene solution process. Hydrazine is generally used to reduce graphene oxide (GO), which results in polluting emissions as well as fixed nitrogen functional groups on different defects in the graphene sheets. To replace hydrazine, we developed eco-friendly reduction agents with similar or better reducing properties, and selected of them for further analysis. In this study, GO layers were produced from graphite flakes using a modified Hummer's method, and rGO layers were reduced using hydrazine hydrate, L-ascorbic acid, and gluconic acid. We measured the particle sizes and the dispersion stabilities in the rGO dispersed solvents for the three agents and analyzed the structural, electrical, and optical properties of the rGO films. The results showed that the degree of reduction was in the order L-ascorbic acid ${\geq}$ hydrazine > glucose. GO reduced using L-ascorbic acid had a sheet resistance of $121k{\Omega}/sq$, while that reduced using gluconic acid showed worse electrical properties than the other two reduction agents. Therefore, L-ascorbic acid is the most suitable eco-friendly reduction agent that can be substituted for hydrazine.

• Hwankyungkyoyuk
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• v.20 no.2
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• pp.78-92
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• 2007

The purindicator and its application through the application of the eco-city concept. To achieve this aim, this study execute to erect eco-city concept, to develop urban evaluation indicator for the fifth and sixth graders of elementary school, to survey for elementary school teacher in Daegu and to develop application of urban evaluation indicator for the fifth and sixth graders of elementary school. The result of study can be summarized as follow. First, erecting the eco-city concept and urban evaluation indicator for the fifth and sixth graders of elementary school was developed with 14 objects, such like that saving and sound circulation of water resource, sound atmosphere. Second, The result of survey, generally, teachers evaluated that Daegu has problems. The degree of interest of urban environmental problem of Daegu showed that each problem had relatively equal distribution. Teachers had positive response that the ecocity concept applied to environmental education of elementary school. Selection of educational contents had distinct tendency with application of the concept of ecocity. Teachers indicated several problems in environmental education of elementary school. Third, We develop application of indicator for the fifth and sixth graders of elementary school. We concluded that developing application of indicator will offer as follows: First, student and teacher can logically understand urban environmental problems. Second, application of indicator had role of useful tool for environmental education of elementary school.

• Journal of the Korean Home Economics Association
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• v.44 no.3 s.217
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• pp.69-77
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• 2006

The purpose of this research was to provide recommendations for eco-centered early childhood education as a new paradigm in Korean society. Questionnaires were collected from directors, teachers, and parents of private & public kindergartens, as well as child care centers, in Bucheon city. The data were analyzed based on the frequencies, $X^2$ test, F test, and Scheffe test. The results were as follows. (a) Most directors, teachers, and parents positively agreed with the eco-centered early childhood education and recognized its benefits. (b) In order for the eco-centered early childhood education to be successful, development of various programs, systematic study, ongoing teacher training, and parents' education were required. (c) In order for the eco-centered early childhood education to develop more culturally appropriate program, close connection with local community, reorganization of the early childhood education curriculum, and government support were needed. The findings demonstrate that eco-centered early childhood education is necessary for the future wellbeing of Korean society.