• Journal of Science Education
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• v.44 no.2
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• pp.225-239
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• 2020

This study aims to analyze the characteristics of reflective thoughts of students during experiments in general physics experiments. The participants were 32 college students, they submitted 10 experiment reports including answers to questions for reflective thinking. The results were as follows: First, students show reflective thinking broadly in the experiment, levels were followed by practical reflection, technical reflection, and critical reflection. Also, they actively accepted the knowledge related to experiments, but were passive in connecting new knowledge and experiences obtained through the experiments or forming new questions. Second, the reflective thinking of students show high correlation with experiments related to prior knowledge or the easy-to-understand process. Third, through the qualitative analysis of open-ended questions, it was confirmed that technical reflection occurs in individual evaluation, practical reflection in group evaluation, and practical reflection and critical reflection in improvement proposal. While the students' reflective thinking were superficial or mainly functional, however, they recursively examined the learning contents and the experimental process concurrently.

• Speech Sciences
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• v.11 no.2
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• pp.227-235
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• 2004

In this paper, we proposed a new practical implementation method of the lattice transversal joint (LTJ) adaptive filter using speech codec's information. And it was applied to the adaptive echo cancellation problem to verify the efficiency of the proposed method. Realtime implementation of the LTJ adaptive filter is very difficult due to high computational complexity for the filter coefficients compensation. However, in case of using speech codec, complexity can be reduced since linear predictive coding (LPC) coefficients are updated each frame or sub-frame instead of every sample. Furthermore, LPC coefficients can be acquired from speech decoder and transformed to the reflection coefficients. Therefore, the computational complexity for updates of the reflection coefficients can be reduced. The effectiveness of the proposed LTJ adaptive filter was verified by the experiments about convergence and tracking performance of the adaptive echo canceller.

• Journal of Korean Elementary Science Education
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• v.32 no.2
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• pp.113-126
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• 2013

In this study, the researcher aimed to increase productive reflection of pre-service elementary teachers through reflective journal writing and discussion after science peer teaching practice. 'Productive reflection' involves consideration and analysis of interrelationships among aspects of teaching including learners and learning, subject matter knowledge, assessment, and instruction. During 8 week efforts, productive reflection has increased gradually in both individual journal and class discussion. However half of individual journals didn't show productive reflection even in the final stage. This implicated that development of reflective thinking is an achievable but progressive change. By describing the progress in discussion and participants' responses on journal writing and discussion activity, this study shed light on practical ways of enhancing reflective teacher education.

• Journal of The Korean Association For Science Education
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• v.33 no.4
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• pp.807-825
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• 2013

This study investigated two science teachers' practical knowledge shaped during their science classes which intend to realize social construction of scientific models. The teachers' practical knowledge was qualitatively examined in terms of five content categories defined by Elbaz through the reflection-in-action based on video data of their teaching as well as the reflection-on-action based on their narratives and interview data obtained after their classes. The results shows: 1) two science teachers implemented their practical knowledge on appropriate subject matter knowledge when they provided students with scaffoldings to support building scientific models during the classes. 2) The teachers' knowledge about science curriculum played important roles to change the purposes of the classes from the transmission of difficult science concepts to the construction of scientific model appropriate to learning goals. 3) The teachers' implementation of pedagogical knowledge changed toward supporting students' group activities and model generations aligned to the intention of social construction of scientific models. 4) The teachers' practical knowledge about their 'selves' showed that a teacher's perception and implementation of his/her roles of helper, guide, or facilitator are important for students to construct scientific models through group activities. 5) The two teachers' practical knowledge the milieu of schooling is realized by their modes of interactions with student groups during their classes. Two teachers acted like a co-player with his students or like a coach to students near a playground. We discussed domain-specific characteristics about scientific model construction.

• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.8-13
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• 2020

To develop cardiovascular simulator capable of implementing pulse waves similar to the human body, accurate information about reflection wave is required. However, the conclusion is still not clear and various discussions are underway. In this study, the pulse wave velocity of the tube used in the experiment was first determined by measuring the pressure waves at two points in a single tube system with the experimental device to implement the pulse wave transmission of blood vessels, and the superposition time and characteristics of the reflection wave were confirmed. After that, an air chamber was set at the reflection site, and the effect of the change of air volume on the reflection wave was investigated. Finally, the effect of the number of branches connected to a single tube on the reflection wave was investigated. The superposition time of the reflection wave can be controlled by the air volume of the air chamber, and the magnitude of the reflection wave is influenced by the number of reflection sites that generate the reflection wave. The results of this study may be of practical assistance to simulator researchers who want to implement pulse wave similar to clinical data. It is expected that the more results similar to clinical are provided, the greater the scope of the simulator's contribution to clinical cardiovascular research.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.322-334
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• 2014

In this study, the researcher aimed to increase productive reflection of pre-service elementary teachers through meta-analysis of their own reflective journals. The meta-analysis activities are expected to enhance their learning effectively as a kind of self-assesment. During 8 week simulation teaching, 26 pre-service teachers kept individual journal writing and the meta-analysis activities were implemented twice (after the 3rd and 8th week). Right after the first meta-analysis, the pre-service teachers' productive reflection increased clearly. However this would not guarantee the effect would last long time period. By analyzing 8 week reflective journals, reports on meta-analysis activities and small group interview, this study shed light on practical ways of enhancing reflective teacher education.

• Journal of Hydrogen and New Energy
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• v.29 no.2
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• pp.163-169
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• 2018

The present article discusses about the measurement techniques of acoustic impedance that becomes one of the important acoustic characteristics of various boundaries found inside of propulsion systems. Acoustic characteristics including acoustic impedance and reflection coefficient can be often assessed and estimated by use of the two-microphone method. Theoretical expressions of acoustic impedance and reflection coefficient measured in an impedance tube are presented for both cases with mean flow and without flow, and the practical application of the method through calibration is also provided. The acoustic impedance and the reflection coefficient are related with axial locations of microphones, thermodynamic characteristics of gas inside, and the transfer function between the pressure wave measurements at multiple locations.

• Korean Medical Education Review
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• v.20 no.2
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• pp.78-90
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• 2018

Recently, unprofessional behavior by physicians and misconduct by medical students have led to increased public concern over medical professionalism. Many studies have been conducted to explore strategies that reinforce professionalism education and prevent misconduct in medical students. However, most studies focused on defining the medical professionalism and its conceptual components. In this study, we conducted a conceptual analysis based on the literature review to categorize issues of unprofessional behavior, and identified doctors' indifference to self and others as the reason for the unprofessional behavior. In this regard, self-reflection provides a practical tool to overcome such indifference. We suggest 'education and evaluation based on self-reflection and reflective practices' as the effective strategies to enhance the professionalism in medical students.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.665-667
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• 2004

In previous studies, charged mosaic membranes having two different fixed charges in the membrane matrix indicated unique transport behavior such as preferential material transport. In this study, the composite charged mosaic membrane endurable to mechanical pressure in practical application was investigated from the same aspect of solute and solvent transport as before. Lp and ${\omega}$ estimated by taking account of active layer thickness were satisfactorily consistent with those in mosaic membrane without reinforcement. On the other hand, the reflection coefficient s indicated the negative value that suggests preferential material transport.

• Journal of Gifted/Talented Education
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• v.20 no.1
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• pp.317-346
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• 2010

The purpose of this study was to investigate the changes in teachers' recognition of science class and children for the gifted, and the process of changes in their practical knowledge after the experience of science class and conversation with colleague teachers. Two elementary teachers, teacher A and B, were selected as subject of investigation, who wanted to improve their science class. They experienced the process of self-examination during their class and from class conversations. Teacher A has 10 years of teaching experience. She has been in contact with gifted children and observed them since undergraduate. She entered the graduate school since she came to be interested in science class and children for the gifted. While teacher B has only three years of teaching experience and had a first contact with the gifted after graduate school. The results of this study are as follows. Teacher A didn't change recognition of gifted children class by class conversation in short term because she had a firm faith in good class teaching and was rich in class teaching knowledge. And, her practical knowledge was applied to the next class by changing teaching method or by supplementing her class contents in concerned part through class observation and class conversation with her colleagues. Teacher B was characterized as being lack of class confidence and concerned more about subject knowledge. She was forming a new practical knowledge along with new class teaching knowledge. Teacher B was in trouble with applying new practical knowledge to next class. From such findings, it was concluded that the process of changing or forming of practical knowledge depends on the beliefs, values, experiences, or knowledges of each teacher. A reflection on one' own class teaching could be a good way to form a practical knowledge and improve teaching speciality, when it was concerned with self-reflection of their own class, class observation, and communication with colleagues. Thus, the reflection practice could be applied to the teaching program of teachers for the gifted to form practical knowledge through trial class, self-reflection of class, and conversation with colleagues.