• Journal of Korean Elementary Science Education
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• v.34 no.4
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• pp.419-433
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• 2015

Analogical reasoning is a central component of human cognition and contributes to scientific discovery and to develop science education. In this study, we investigated the process features of lower elementary school students' analogical reasoning to explain mixture concept. The subjects are 24 lower elementary students. And the research design includes three phases instruction to investigate the features of students' self generated analogy. Phase 1 is the introduction of analogy in which student learn to use analogy. Phase 2 is a POE class about mixture conception. Piaget and Inhelder studied the conception of mixing among children in relation to cognitive development. In phase 2, we taught the student with Piaget and Inhelder's the experiment and observed the features of learning process about mixture conception. Phase 3 is students' generation of analogy (self generated analogy) for the experienced phenomena in phase 2. We analyzed the students' responses through the three phases in the view of Gentner's Structure Mapping Theory. The results showed that many lower elementary school students even before formal operation stage understood the mixture conception and made well their self generated analogy to explain the mixture conception in spite of the difficulty of making self generated analogy.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.148-155
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• 2020

This study investigated learners' perceptions of using self-generated listening materials based on Text to Speech. After taking an online training session to learn how to make listening materials for extensive listening practice outside the classroom, the learners were engaged in practice with self-generated listening materials for 10 weeks in a self-directed way. The results show that a majority of the learners found the TTS-based listening materials helpful to reduce anxiety toward listening and enhance self-confidence and motivation, with a positive effect on improving their listening ability. The learners' general satisfaction can be attributed to some beneficial features of TTS-based listening material, including freedom to choose what they want to learn, convenient accessibility to the material, availability of various native speakers' voices, and novelty of digital tools. This suggests that TTS-based digital listening materials can be a useful educational tool to support learners' self-directed listening practice outside the classroom in EFL settings.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.90-96
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• 1998

There are various noises generated by friction. Among the rest, eliminating squeal noise generated during braking is an important task for the improvement of vehicle passengers' comfort. The parameters affecting brake squeal noise are the material properties of the braking pad, the dynamic properties of the brake parts and the dimensions of the brake assemble etc. Also, the squeal noise changes its inherent form(i.e. its sound pressure level and its frequency) with the normal load and sliding speed. In this study, the characteristics of brake squeal noise generated by friction is analyzed experimentally. The experiment focused on the analysis of friction self-excited vibrationand squeal noise level. Friction self-excited vibration is caused by the dry friction between pads and rotor, and occurs as a function of their relative sliding speeds. And Friction self-excited vibration is raised the brake squeal noise.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.26-31
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• 2000

There are various noises generated by friction. Among the rest, eliminating squeal noise generated during braking is an important task for the improvement of vehicle passengers' comfort. The parameters affecting brake squeal noise are the material properties of the braking pad, the dynamic properties of the brake parts and the dimensions of the brake assembly etc. Also, the squeal noise changes its inherent form with the normal load and sliding speed. In this study, the characteristics of brake squeal noise generated by friction is analyzed experimentally. The experiment focused on the analysis of friction self-excited vibration and squeal noise level. Friction self-excited vibration is caused by the dry friction between pads and rotor, and occurs as a function of their relative sliding speeds. And Friction self-excited vibration is raised the brake squeal noise.

• Elastomers and Composites
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• v.50 no.2
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• pp.132-137
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• 2015

A self actuated photocatalyst $Weltouch^{(R)}$ used to the remove the odor gases generated in the foaming process of shoes insole was prepared by sol-gel method and studied its property. Specially, with mixing $Weltouch^{(R)}$ in the foaming process of shoes insole, the physical functionality such as specific gravity, hardness, elongation, compression set was studied. The physical functionality of shoes insole was no variation by added $Weltouch^{(R)}$. The odor gases generated in the foaming process of shoes insole was detected to be reduced to 60~80% by self actuated photocataylst $Weltouch^{(R)}$ even in the dark conditions, which was observed for both anatase and rutile phase.

• Journal of The Korean Association For Science Education
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• v.37 no.3
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• pp.407-416
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• 2017

In this study, we investigated the processes of analogy change and the characteristics of discussions in collaborative activity of self-generated analogy. Twenty-four high school students in Seoul participated in this study. We implemented science instructions based on collaborative activity of self-generated analogy. We compared personal analogies, group analogies, and modified group analogies in order to analyze the processes of analogy change. We also analyzed the characteristics of group and classroom discussions in the science instructions. The analyses of the results indicated that the processes of analogy change were categorized into three patterns; adding shared attributes, recognizing unshared attributes, and revising mapping errors. They selected a group analogy from analogies of their group members by considering inclusiveness, originality, and familiarity. They perceived the activity of self-generated analogy as subjective and creative. Therefore, they felt little pressure of self-generated analogy and there were little conflicts in group discussions. On the other hand, various analogies were suggested in classroom discussions and the competitive atmosphere of classroom discussions led students to focus on unshared attributes. At the stage of modifying group analogies, they added unshared attributes as limitations of the group analogy and changed their group analogy not to have unshared attributes. There were no cases of generating a new analogy. Some suggestions to implement collaborative activity of self-generated analogy in science teaching effectively are discussed.

• Communications of the Korean Mathematical Society
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• v.14 no.1
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• pp.1-12
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• 1999

The faithful bi-module \ulcornerM\ulcorner with its endomorphism ring End\ulcorner(M) such that M\ulcorner is flat (in other words, End\ulcorner(M)-flat, or endo-flat)and with a commutative ring R containing an identity has been studied in this paper. The chain conditions of a faithful endo-flat module \ulcornerM relative to those of the endomorphism ring End\ulcorner(M) having the zero annihilator of each non-zero endomorphism are studied.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.379-382
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• 2000

We designed a self-timed interface circuit for efficient communication in IP (Intellectual Property)-based system with high-speed self-timed FIFO and a set of self-timed event logic library with 0.25um CMOS technology. Optimized self-timed standard cell layouts and Verilog models are generated for top-down design methodology. A method for mitigating a design bottleneck when it comes to tolerate clock skew is described. With clock control method and FIFO, we implemented high-speed 32bit-interface chip for self-timed system, which generated maximum system clock is 2.2GHz. The size of the core is about 1.1mm x 1.1mm.

• Korean Journal of Mathematics
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• v.6 no.2
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• pp.259-279
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• 1998

For the forward-backward semimartingale, we can define the backward semimartingale flow which is generated by the backward canonical stochastic differential equation. Therefore, we define the backward self-similar stochastic processes, and we study the backward self-similar stochastic flows through the canonical stochastic differential equations.

• Progress in Superconductivity
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• v.10 no.2
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• pp.69-73
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• 2009

For extraction of the self-energy from the angle resolved photoemission spectroscopy(ARPES) experiments for the cuprate superconductors, the momentum distribution curve(MDC) analysis is commonly used. There are two requirements for this method to work: the self-energy is momentum independent and the bare electron dispersion is known. Assuming that the first condition is satisfied in the cuprates, we checked the effects of the bare dispersion on the extracted self-energy. For this, we first generated the ARPES intensity using the tight-binding band of the B2212 by solving the Eliashberg equation. We then extracted the self-energy from the theoretically generated ARPES intensity using the linear and quadratic dispersions. By choosing the bare dispersion such that the Kramer-Kronig relation is best satisfied between the real and imaginary parts of the extracted self-energy, we confirmed that the quadratic dispersion is better for the bare electron band for Bi2212. The self-energy can be reasonably extracted from the ARPES experiments using the MDC analysis.