• Journal of The Korean Association For Science Education
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• v.27 no.9
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• pp.870-880
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• 2007

The purpose of this study was to understand the change and characteristics of interactions in a heterogeneous group in scientific inquiry experiments. For this purpose, the process of students' interactions in small group activities were analyzed. This study focused on two, small heterogeneous groups of eighth graders. Students were involved in 13 scientific inquiry experiments for one year and students' interactions in each experiments were observed and recorded using video/audio and the data recorded were transcribed. The analysis of data was based on the method of making a note by looking and listening to the data repeatedly. Students' interactions in heterogeneous group changed toward that 3A (early formal operation student solved the problems by oneself and other students only listened to 3A student's explanation or copied the answer. The least able student was alienated from peers' interactions. In the meantime, new interactions of two middle level students were shaped. Educational implications of the progression of activities emphasizing interactions and the organization of grouping were drawn.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2419-2421
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• 2009

A simple and efficient method has been developed for Knoevenagel condensation between aldehydes or ketones and active methylene group by stirring in methylene chloride at 60 ${^{\circ}C}$ under heterogeneous conditions using silica supported ammonium acetate. The products are obtained in excellent yields and are in a state of high purity. The structures of the products were confirmed by IR, $^1H$ NMR and mass spectral data and comparison with authentic samples available commercially.

• Clean Technology
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• v.22 no.4
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• pp.250-257
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• 2016

As an attempt to replacing petroleum-based chemicals with bio-based ones, synthesis of furfural from biomass-derived xylose attracts much attention in recent days. Conventionally, furfural from xylose has been produced via the utilization of highly corrosive, toxic, and environmentally unfriendly mineral acids such as sulfuric acid or hydrochloric acid. In this study, microwave-assisted biphasic reaction process in the presence of novel bio-based heterogeneous acid catalysts was developed for the eco-benign and effective synthesis of furfural from xylose. The microwave was irradiated for reaction acceleration and a biphasic system consisting of $H_2O$ : MIBK (1 : 2) was designed for continuous extraction of furfural into the organic phase in order to reduce the undesired side products formed by decomposition/condensation/oligomerization in the acidic aqueous phase. Moreover, sulfonated amorphous carbonaceous materials were prepared from wood powder, the most abundant lignocellulosic biomass. The prepared catalysts were characterized by FT-IR, XPS, BET, elemental analysis and they were used as bio-based heterogeneous acid catalysts for the dehydration of xylose into furfural more effectively. For further optimization, the effect of temperature, reaction time, water/organic solvent ratio, and substrate/catalyst ratio on the xylose conversion and furfural yield were investigated and 100% conversion of xylose and 74% yield of furfural was achieved within 5 h at $180^{\circ}C$. The bio-based heterogeneous acid catalysts could be used three times without any significant loss of activity. This greener protocol provides highly selective conversion of xylose to furfural as well as facile isolation of product and bio-based heterogeneous acid catalysts can alternate the environmentally-burdened mineral acids.

• Journal of applied mathematics & informatics
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• v.8 no.3
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• pp.919-934
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• 2001

The concepts of material frame-indifference and material symmetry group with respect to isotropic scalar functions, as represented by energy functions, are discussed. An energy function for a structured heterogeneous (transversal isotropic) medium in large elastic deformations, which is known to satisfy the Ponyting’s effect [1], is highlighted. It is shown that the constitutive relation due to this energt function is material frame-indifferent.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.7
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• pp.51-59
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• 1996

The current network environment is composed of heterogeneous H/W and S/W resources. Integrating CSCW applications in such heterogeneous environments is highly complex. This paper describes the design and implementation of ASS (application sharing server) which supprot sharing of a single application between different operating systems. The ASS supports cooperative work among user group using its own window system (X-windwo or MS-windwos). We adopted improved managing heavy-weight data. ASS also provides development environment for vaious groupware application.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.668-676
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• 2001

In order to comprehend the internal processes of heterogeneous small-group cooperative learning in science class, this study investigated verbal interaction patterns by the achievement level. Frequency of verbal behaviors was compared in respect of the achievement level, and participation patterns and characteristics were investigated. Verbal interaction patterns by the achievement level were also analyzed based on students' perceptions of interactions. It was found that there were no significant frequency differences between high- and medium-achieving students' verbal behaviors. The verbal interaction patterns showed co-construction processes between high- and medium-achieving students, which was consistent with the students' perceptions of interactions. These suggested that medium-achieving students actively participated in small-group interactions in science class.

• Journal of the Korean Statistical Society
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• v.36 no.1
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• pp.129-148
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• 2007

Frailty estimates from the proportional hazards frailty model often lead us to conjecture the heterogeneity in frailty such that the variance of the frailty varies over different covariate groups (e.g. male group versus female group). For such systematic heterogeneity in frailty, we consider a regression model for the variance components in the proportional hazards frailty model, denoted by the MLFM. However, in many cases, the observed data do not show any statistically significant preference between the homogeneous frailty model and the heterogeneous frailty model. In this paper, we propose a Bayesian model averaging procedure with the reversible jump Markov chain Monte Carlo which selects the appropriate model automatically. The resulting regression coefficient estimate ignores the model uncertainty from the frailty distribution in view of Bayesian model averaging (Hoeting et al., 1999). Finally, the proposed model and the estimation procedure are illustrated through the analysis of the kidney infection data in McGilchrist and Aisbett (1991) and a simulation study is implemented.

• Journal of Korean Elementary Science Education
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• v.38 no.1
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• pp.1-15
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• 2019

This study aimed to identify the effects of students' empathy ability on group creativity, when elementary school students perform scientific activity designed to express group creativity. A total of 12 elementary students from a fifth-grade science club participated in this study. A pretest to examine the students' empathic ability was performed to classify them into three groups: A group with high, low and heterogeneous empathic members. The linguistic interaction was analyzed to determine the process of group creativity manifestation; the results were classified into 'metacognitive', 'cognitive', and 'social-communicative'. As a result, groups with high empathic ability showed more frequent interaction in monitoring, planning, and divergent thinking. On the other hand, in the case of the group with low level of empathy, it was confirmed that there are many interactions related to regulation, convergent thinking, and noncohesive prosocial interaction. Also, in the case of heterogeneous group with empathy ability, group creativity utterance on all sides was relatively higher than other groups. As a result of this study, we could confirm the influence of empathy as a strategy to help the group creativity and discuss the educational implications.

• Journal of Korean Home Economics Education Association
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• v.12 no.1
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• pp.47-58
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• 2000

The purpose of this study is to investigate the effects of cooperative learning method on student achievement and attitude in Home Economics. and that what sort of effectiveness be existed between the two groups. Homogeneous & Heterogeneous one in achievement. A junior middle school in Kwangju was served for the study. Setting two groups: One is for cooperative learning and other for traditional learning. Two classes were provided with cooperative learning method. while one class with traditional learning method. Two hours of a week were devoted for the experiment. and it was also planned to be lasted six weeks from the third of June. 1998. until the 13th of July. 1998. The results are as follows: 1) Student achievement from cooperative learning method showed a little higher than those from traditional learning method. 2) Cooperative learning method was more effective than traditional learning method. mental attitude toward school. lessons and teachers were more higher than those the traditional learning method. 3) The group of Heterogeneous members was higher than the group of Homogeneous members in their student achievement. 4) It is noticeable that two groups under cooperative learning method. however showed some difference when each of them is placed in different organization. The group of Heterogeneous members was more affirmative attitude toward school. lessons and teachers than the one Homogeneous members.

• The Mathematical Education
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• v.54 no.4
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• pp.335-350
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• 2015

The purpose of this study was to investigate the effectiveness of the differentiated instruction in mathematics by a meta-analysis. Among the studies conducted for last twenty three years, the relevant 49 research articles were selected, 80 effect sizes were calculated for the cognitive domain and 70 effect sizes for the affective domain. Effect sizes were analyzed with school levels, student level, group organization method such as homogeneous vs. heterogeneous, class transfer and adjusting class sizes for each cognitive domain and affective domain. The results are as the followings: In the cognitive domain, the overall effect size of the differentiated instruction produced a medium effect(effect size=0.68, U3=75.17%). The differentiated instruction showed the highest effect size on elementary school and middle school, mid level students, heterogeneous group, class transfer and not adjusted class size. And in the affective domain, the overall effect size of the differentiated instruction produced a low effect(effect size=0.36, U3=65.36%). The differentiated instruction showed the highest effect size on elementary school, mid level students, and heterogeneous group. Thus the differentiated instruction was proved to be effective in mathematics classes.