• Title, Summary, Keyword: reflection

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Efficient Algorithm for the Real-time Generation of Reflection Lines (자동차 스타일링을 위한 반사선의 실시간 생성 및 표현 알고리듬)

  • Gang, Ju-Yeop;Lee, Geon-U
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1
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    • pp.173-181
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    • 2000
  • Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface. This capability is very important because the defect of the surface requires the rework of the dies that causes a big loss in cost and delivery time. To simulate the reflection line test in the actual production line, a faster generation algorithm is presented. Among., various surface interrogation methods using reflection lines, Blinn-Newell type of reflection mapping is applied to generate reflection lines on the trimmed NURBS surface. The generation of reflection lines is formulated as a surface-plane intersection problem, and solved by surface-contouring techniques. In addition, a modified reflection map is proposed to eliminate the discontinuity of reflection lines due to the configuration of the reflection map. A fast reflection line algorithm is developed utilizing an efficient traced contouring technique, and proved to be well suited for real-time quality-assessment task.

The basic theoretical research for a practice of university faculty member's teaching reflection (대학교수의 수업성찰 실천을 위한 이론적 기초 탐구)

  • Keum, Hye-Jin
    • Journal of Digital Convergence
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    • v.14 no.2
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    • pp.57-63
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    • 2016
  • The purpose of this study is to draw implications about a practice of university faculty member's teaching reflection by considering the concept, process, and content of reflection as a theoretical basis of teaching reflection. The concept of reflection is based upon 'reflection-in-action' suggested by $Sch{\ddot{o}}n$, and the process and content of reflection is explained through Korthagen's Core Reflection model. The following three implications conclude: First, a faculty member should write a reflection journal by observing and reflecting consistently one's own behavior in a context of teaching. Second, the center for teaching and learning should provide an orientation and consultation about the content and process of teaching reflection. Finally, sharing lessons with the colleague faculty member is required to make an effective reflection for each faculty member.

BRAGG RESONANT REFLECTION OF OBLIQUELY INCIDENT WATER WAVES

  • Cho, Yong-Sik
    • Water Engineering Research
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    • v.1 no.1
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    • pp.75-81
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    • 2000
  • The bragg reflection of obliquely incident monochromatic water waves propagating over a sinusoidally varying topography is theoretically investigated in this study. The eigenfunction expansion method is first employed to calculate reflection coefficients of water waves due to depth changes. A reasonable agreement is observed. Obtained reflection coefficients of normally incident waves are compared with laboratory measurements. Reflection coefficients of obliquely incident waves are then calculated. The wavenumber providing the Bragg reflection agrees well with analytical predictions.

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Efficient Algorithm for Real-time Generation of Reflection Lines

  • Kim, Tae-wan;Juyup Kang;Lee, Kunwoo;Park, Sangkun
    • Journal of Mechanical Science and Technology
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    • v.15 no.2
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    • pp.160-171
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    • 2001
  • Depending upon the method of the surface generation and the quality of the designed boundary curves, the resulting surfaces may have global or local irregularities in many cases. Thus, it would be necessary for the designer to evaluate the surface quality and to modify the surface. This is very important because the defect of the surface causes the rework of the dies, increasing cost and delivery time significantly. To simulate the reflection line test in the actual production line, a faster algorithm for generating reflection lines is presented. In this paper, among various surface interrogation methods using reflection lines, Blinn-Newell type of reflection mapping is applied to generate the reflection lines on the trimmed NURBS surfaces. The derivation of reflection lines is formulated as a surface-plane intersection problem (Jung 1994) and is solved by surface-contouring techniques. Also, for eliminating the discontinuity of reflection lines due to the configuration of reflection map, a modified reflection map is proposed. An efficient traced contouring technique is utilized for the computational efficiency and proves to be well suited for the real-time quality-assessment task.

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The Patterns and Characteristics of Preservice Elementary Teachers' Reflection in Reflective Journal Writing (초등 예비 교사의 반성적 글쓰기에서 나타나는 반성의 유형과 특징)

  • Lee, Jeong-A
    • Journal of Korean Elementary Science Education
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    • v.29 no.3
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    • pp.378-388
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    • 2010
  • This study aimed at categorizing preservice teachers' reflections and understanding their characteristics in reflective journal writing after microteaching. Thirty-two preservice elementary teachers joined in this study. As results, three patterns were categorized: Reflection with practice, Reflection to be practice, Reflection with suspension of judgment. 'Reflection with practice' changed the topology of science class in active. 'Reflection to be practice' had clear focus in reflection and suggested orientations to succeed in the next teaching. 'Reflection with suspension of judgment' made something fall into abeyance, because it couldn't provide an orientation for teaching. After discussing these results, implications toward preservice teacher education were explored.

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Efficient generation of reflection lines to evaluate car body surfaces (자동차 외형설계곡면의 검사를 위한 효율적인 반사선의 생성)

  • 최인진;이건우
    • Korean Journal of Computational Design and Engineering
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    • v.2 no.3
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    • pp.133-141
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    • 1997
  • In the process of car body design, various surfaces are generated from the given boundary curves. Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface or to use the different generation method based on the evaluation results. This capability is very important because the defect of the surface quality detected in the production stage will require the rework of the dies and will cause a big loss in cost and time. A method of surface interrogation using reflection line is introduced. In this paper, We applied reflection mapping to generate reflection lines on the trimmed NURBS surface. Since reflection lines are obtained from reflection mapping that uses simple and physically acceptable mapping algorithm, they can be efficiently used to simulate the reflection test on the real part in the production line.

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Analysis of Students' Reflective Journals on Medical Communication Role Plays (의료면담 역할극 사례의 학습자 성찰일지 분석)

  • Kim, Young Jon;Lee, Seung Hyun;Yoo, Hyo Hyun
    • Korean Medical Education Review
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    • v.19 no.3
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    • pp.169-174
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    • 2017
  • This study explores the phenomenon of learner reflection in writing. Sixty-nine reflection logs were submitted by students after medical interview role plays. Using thematic analysis methodology, the following three steps were carried out: (1) the entire contents of the logs were analyzed and coded, (2) the coded contents were reclassified and categorized into higher themes, and (3) all reflection logs were re-analyzed to derive the frequency according to their classifications. The learners' reflection contents were classified into 'preparation,' 'experience,' and 'future plan.' The levels of reflection were 'simple information and appreciation,' 'acquisition and application of knowledge,' and 'analysis and criticism.' The types of reflection were identified only at the level of 'analysis and criticism' and could be classified into 'relativization,' 'objectification,' and 'internalization.' Students' reflection levels were highest in the levels of 'acquisition and application of knowledge' (49.3%), and 'analysis and criticism' (37.7%). A total of 14.5% of the students showed 'internalization.' In order to enable internalized reflection at a critical level, instructional strategies to induce and promote reflection are needed.

Application of Minimum Phase Condition to the Acoustic Reflection Coefficient Measurement (최소 위상 조건을 적용한 음향 반사계수 측정)

  • Heo, Jun-Hyeok;Kim, Deok-Ki;Lim, Byoung-Duk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.10
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    • pp.1131-1136
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    • 2005
  • For the accurate measurement of acoustic properties of a surface, efforts have been made to reduce errors caused by external disturbance. If the reflection coefficient is considered as a transfer function between reflected wane and incident wave, the causality is required between them and the reflection coefficient should be of minimum phase. In this thesis, the minimum phase condition is applied to measure correct reflection coefficient. The reflection coefficient is approximated as a rational function In the Z domain by minimizing the sum square error. Then the minimum phase reflection coefficient is reconstructed using the distribution of poles and zeros of the reflection coefficient model.

Application of Minimum Phase Condition to Acoustic Impedance Measurement (최소 위상 조건을 적용한 음향 임피던스 측정)

  • Lim, Byoung-Duk;Heo, Jun-Hyeok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.855-860
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    • 2005
  • For the accurate measurement of acoustic properties of a surface, efforts have been made to reduce errors caused by external disturbance. If the reflection coefficient is considered as a transfer function between reflected wave and incident wave, causality is required between them and the reflection coefficient should be of minimum phase. In this thesis, the minimum phase condition is applied to measure correct reflection coefficient. The reflection coefficient is approximated as a rational function in the Z domain by minimizing the sum square error. Then the minimum phase reflection coefficient is reconstructed using the distribution of poles and zeros of the reflection coefficient model. The incident wave, the reflected wave and the impulse response function of causality are recalculated from the minimum phase reflection coefficient for further applications.

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The effect of the flange attached to the inclined exit of tube on the sound reflection coefficient (관 경사출구에 부착된 플랜지가 음향반사계수에 미치는 영향)

  • Baek, Du-San;Yang, Yoon-Sang;Lee, Dong-Hoon;Jo, Jae-Hyeong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.618-621
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    • 2014
  • This research is to review the possibility of reducing the noise radiated from the tube exit by controling the sound reflection coefficient at the inclined exit. The sound reflection coefficient at the inclined exit of flanged tube was measured by both transfer function method and standing wave ratio method. Accuracy on the sound reflection coefficient measured by transfer function method was verified through comparison with sound reflection coefficient measured by standing ratio method. The flanged tube had lower sound reflection coefficient than the tube which have no flange. Also the sound reflection coefficient was decreased in accordance with increasing the inclined angle of unflanged tube.

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