• 한국초등과학교육학회지:초등과학교육
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• 제34권4호
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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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• 제12권4호
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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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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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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• 제50권2호
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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.

• 한국과학교육학회지
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• 제37권3호
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• pp.407-416
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• 2017

이 연구에서는 협력적 비유 생성 활동에서 나타나는 비유의 변화과정과 소집단 및 전체 학급 토론의 특징을 분석하였다. 서울특별시에 소재한 고등학교에 재학 중인 24명의 학생을 대상으로 협력적 비유 생성 활동을 적용한 수업을 진행하였다. 학생들이 생성한 개인 비유와 소집단 비유, 수정된 소집단 비유를 비교하여 비유의 변화과정을 분석하였으며, 비유 생성 활동을 위한 소집단 토론과 전체 학급 토론의 특징을 분석하였다. 연구 결과, 비유의 변화 과정은 공유속성이 추가되는 경우, 비공유 속성을 인식하는 경우, 대응 오류가 수정되는 경우의 세 가지 변화 유형이 나타났다. 학생들은 여러 개인 비유 중 하나를 선택하는 방식으로 소집단 비유를 생성하였고, 이때 비유의 설명력, 독창성, 친숙도 등을 고려하는 것으로 나타났다. 학생들은 비유 생성 활동을 주관적이고 창의적인 활동이라고 인식하여 비유 생성 활동에 대한 정서적 부담감이 적었고 소집단 토론에서 갈등의 요소도 적었다. 전체 학급 토론에서는 다양한 비유가 제시되었으며 전체 학급 토론의 경쟁적인 분위기는 학생들이 비유가 갖는 비공유 속성에 주목하게 하였다. 소집단 비유 수정 단계에서 학생들은 비공유 속성을 비유가 갖는 제한점으로 추가하거나 비공유 속성을 갖지 않도록 비유를 변형하는 방식으로 비유를 수정하였고, 새로운 비유를 생성하는 경우는 거의 없었다. 이상의 결과를 바탕으로 협력적 비유 생성 활동을 적용한 수업을 효과적으로 진행하기 위한 방안을 논의하였다.

• 대한수학회논문집
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• 제14권1호
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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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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• 제6권2호
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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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• 제10권2호
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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.