• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1238-1243
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• 2002

In this study, the validity of the acoustic impedance model and the estimation model by electro-acoustic analogy suggested by Maa for predicting the absorptive performance of multiple layer perforated plate systems is investigated. From the comparison between the experiment and calculation for the absorption performance of double layer perforated plate system, the calculated results of using Rao and Munjal's impedance model and transfer matrix method are closer to the experimental values than those of using Maa's impedance model and electro-acoustic analogy. Therefore, in order to apply the acoustic impedance model and the estimation model by electro-acoustic analogy suggested by Maa to the multiple layer perforated plate systems, it is necessary that the suggested acoustic impedance and estimation models should be re-examined.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.3
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• pp.180-185
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• 2003

The equivalent electroacoustic circuit approach has been conventionally used for the analysis of the multiple layer perforated plate system. However, it is found that an analogy error has been involved in the equivalent electroacoustic approach proposed by previous researchers for the element of straight pipe. Although the pipe between the perforated layers is a distributed element in the analogy, it has been treated as a parallel element by previous investigators. The analogy error is demonstrated by comparing the calculated absorption coefficients based on the parallel circuit and the distributed circuit, respectively, with the measured values by the two-microphone impedance tube method.

• Journal of The Korean Association For Science Education
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• v.21 no.1
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• pp.114-121
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• 2001

This study investigated the effect of presenting modes of multiple analogies on middle school students' understanding of science concepts. A total of 122 7th-graders was randomly assigned to one of 4 groups. After reading one of 4 analogy-learning materials in different analogy presenting modes (the number of analogs, the number of mappings between analog and target, and the comparison of similarity between analogs). the students took a conception test. The results indicated that using analogs and mappings twice were not significant factors in recalling and applying science concepts. However, the comparison of similarity between analogs was found to be a significant factor in applying science concepts. Educational implications are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.890-895
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• 2002

The equivalent electroacoustic circuit approach has been conventionally used for estimating the absorption coefficient of a single layer perforated plate system. When the single layer system is extended to the multiple layer ones, however, it is found that an analogy error has been involved in the equivalent electroacoustic parallel circuit approach proposed by previous investigators. The analogy error is demonstrated by the corrected equivalent electroacoustic circuit approach in this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.387.2-387
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• 2002

The equivalent electroacoustic circuit approach has been conventionally used for estimating the absorption coefficient of a single layer perforated plate system. When the single layer system is extended to the multiple layer ones, however, it is found that an analogy error has been involved in the equivalent electroacoustic parallel circuit approach proposed by previous researchers. The analogy error is demonstrated by the corrected equivalent electroacoustir circuit approach proposed en this study.

• Journal of The Korean Association For Science Education
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• v.19 no.3
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• pp.471-478
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• 1999

In this study, the relationships among learners' cognitive variables, motivational variables, and conceptual understandings in learning with analogy were investigated. The instruments regarding analogical reasoning ability, field dependence-independence, mental capacity, and logical thinking ability were administered. Some subtests (self-efficacy, expectancy, self-concept of ability, and value) of the Patterns of Adaptive Learning Survey were administered. After students learned with a worksheet that included analogy, a conception test regarding 'stoichiometry that included limiting reagent' was also administered. It was found that learners' conceptual understandings were significantly correlated with the logical thinking ability and the field dependence-independence among the cognitive variables, and the self-efficacy and the self-concept of ability among the motivational variables. The multiple regression analysis of the cognitive variables on conceptual understandings revealed that the logical thinking ability was the most significant predictor. The field dependence-independence also had predictive power. In the analysis of the motivational variables, the self concept of ability was the only significant predictor.

• Education of Primary School Mathematics
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• v.17 no.1
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• pp.1-16
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• 2014

The purpose of this study is to analyze whether analogy distance and mathematical knowledge affect on transfer problems solving with different analogy distance. To conduct the study, transfer problems were classified into multiple categories: mathematical word problem based on rates, science word problem based on rates, and real-life problem based on rates with different analogy distance. Then analysed there are differences in participants' transfer ability and which mathematical knowledge contributes to the solution on over the three transfer problem. The study demonstrated a statistical significant difference(.05) in participants' three transfer problem solving and a gradual decrease of the participants' success rates of on transfer problems solving. Moreover, conceptual knowledge influenced transfer problem solving more than factual knowledge about rates. The study has an important implications in that it provided new direction for study about transfer of learning, and also show a good mathematics instruction on where teachers will put the focus in mathematical lesson to foster elementary students' transfer ability.

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.177-182
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• 2001

An instructional model using multiple analogies according to component process (MACP) was designed on the vasis of schema theory and comornent process theory in analogical reasoning. This model has ？ phases: introducting multiple analsgs, extracting multiple analogs, extracting common attributes of analogs, introducing target conanother context. Te instructional effects of this model upon students' conceptual understanding and learning motivation were compared with those of the Teaching-With-Analogy (TWA) and non-analogy instructions. Three classes of 8th grade were randomly assigned to MACP, TWA, and control group, respectively, Subjects were taught about chemical changes and reactions for 10 class hours. The ANCOVA results indicated that the scores of the conceptions test for the MACP group were significantly higher than for the control graup. However, no significant differences were found among the three groups in the test scores of learning motivation.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.65-73
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• 2004

Fatigue crack growth from surface defects is one of the most important subjects for the evaluation and the assurance of safety in pressure vessels, piping systems, LPG/LNG fuel tank and other various structures. This paper attempts to analysis some practical or general problems such as the estimation of crack growth life to penetrate the plate thickness, based on fatigue crack growth a single surface flaw and the interaction of multiple flaws. An experiment on the coalescence of multiple undercuts was carried out under cyclic tension condition as a attempt to the analysis of multiple crack problems. It is noted that the fracture strength is characterized by the analogy to that in a single crack growth.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.317-322
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• 2001

A mathematical modelling technique is proposed for estimating the additional bending stresses of tube(s)-in-tube structures due to tube-tube interaction, which has a significant effects on the shear-lag phenomenon. The proposed method simulates the framed-tube structures with multiple internal tubes as equivalent multiple tubes, each composed of four equivalent orthotropic plate panels. Hence, the tube(s)-in-tube structure can be analysed by using an analogy approach where each tube is individually modelled by a continuous beam that can account for the flexural and shear deformations as well as the shear-lag effects. The numerical analysis is applicable for the structural analysis of framed-tube structures with single and multiple internal tubes, as well as those without internal tubes. The shear-lag phenomenon of such structures is studied with additiona] bending stresses and shear-lag reversal points.