• 한국초등과학교육학회지:초등과학교육
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• 제37권3호
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• pp.285-295
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• 2018

The purpose of this study is comparing cognitive development of elementary $4^{th}$ graders and cognitive demand of activities in lesson 'The mirror and the shadow.' Also, the researchers tried to reveal how cognitive development of elementary $4^{th}$ graders and cognitive demand of textbook activities affects the achievement of students. To study students' cognitive development, the researchers use GALT(Group Assessment of Logical Thinking). Piaget's scientific thinking is used to evaluate cognitive demand of textbook activities. With several experts in science education the researchers discussed which scientific thinking is contained in each activities. The results were followed as : (1) The third of activities are significantly affected by students' cognitive development. (2) The another third of activities are influenced by not only students' cognitive development but also other factors experimental instrument. (3) The environmental factors had meaningful impact on the other third of activities.

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.245-250
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• 1998

Novel fabrication process of vertical spring for micro mirror array is proposed. The proposed fabrication process adopts a shadow evaporation process using shielding screen structure on top of the sacrificial layer. The 50${\times}$50 micro mirror arrays are fabricated using the proposed process and ceramic packaged. The static and dynamic characteristics of mirror are measured. The mirror plate touches substrate at 16V and the response time of about 16.8 ${\mu}\textrm{s}$. The resonant frequency of mirror is 16kHz. The spring thickness is calculated from static characteristic to be 1075${\AA}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.416-418
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• 1996

A $50{\times}50{\mu}m^2$ aluminum micromirror array is fabricated using surface micromachining technology. $50{\times}50$ micromirrors are arrayed two dimensionally. The micromirror plate is supported by a vertical spring structure that is placed underneath the mirror plate. When the mirror plates reflect a light, the micromirror array un have large effective reflecting area. Fabrication of vertical spring uses only one mask and shadow evaporation process.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.115-123
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• 2012

A video analysis system used to detect events in video streams generally has several processes, including object detection, object trajectories analysis, and recognition of the trajectories by comparison with an a priori trained model. However, these processes do not work well in a complex environment that has many occlusions, mirror effects, and/or shadow effects. We propose a new approach to a context-aware video surveillance system to detect predefined contexts in video streams. The proposed system consists of two modules: a feature extractor and a context recognizer. The feature extractor calculates the moving energy that represents the amount of moving objects in a video stream and the stationary energy that represents the amount of still objects in a video stream. We represent situations and events as motion changes and stationary energy in video streams. The context recognizer determines whether predefined contexts are included in video streams using the extracted moving and stationary energies from a feature extractor. To train each context model and recognize predefined contexts in video streams, we propose and use a new ensemble classifier based on the AdaBoost algorithm, DAdaBoost, which is one of the most famous ensemble classifier algorithms. Our proposed approach is expected to be a robust method in more complex environments that have a mirror effect and/or a shadow effect.

• 전기학회논문지
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• 제59권3호
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• pp.636-644
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• 2010

A method for the detection of on-road succeeding vehicles using visual characteristic features like horizontal edges, shadow, symmetry and intensity is proposed. The proposed method uses the prominent horizontal edges along with the shadow under the vehicle to generate an initial estimate of the vehicle-road surface contact. Fast symmetry detection, utilizing the edge pixels, is then performed to detect the presence of vertically symmetric object, possibly vehicle, in the region above the initially estimated vehicle-road surface contact. A window defined by the horizontal and the vertical line obtained from above along with local perspective information provides a narrow region for the final search of the vehicle. A bounding box around the vehicle is extracted from the horizontal edges, symmetry histogram and a proposed squared difference of intensity measure. Experiments have been performed on natural traffic scenes obtained from a camera mounted on the side view mirror of a host vehicle demonstrate good and reliable performance of the proposed method.

• 한국과학교육학회지
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• 제43권3호
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• pp.253-263
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• 2023

이 연구에서는 초등학교 과학 빛의 직진과 반사 단원의 교사용 지도서 텍스트와 초등예비교사의 내용 지식 체계 사이의 불일치를 탐색하였다. 이를 위하여 교육대학교에 재학 중인 초등예비교사 279명이 교사용 지도서의 '그림자와 거울' 단원의 정해진 분량을 읽고 생성한 과학 지식에 대한 질문 455개와 답변 543개를 분석하였다. 질문은 과학 개념의 종류와 불일치 유형에 따라 분류하였고, 답변은 정확도를 분석하였다. 질문의 과학 개념을 분석한 결과, 초등예비교사들은 직진 개념에서는 그림자에 대해, 반사에서는 상에 대해, 그 외 개념에서는 광원에 대해 가장 궁금해하였다. 부정확한 답변이나 무응답률이 높아서 정답률이 낮은 질문은 반사에 의한 빛의 중첩, 실험도구의 원리, 렌즈에 의한 상 등으로 초등과학 교육과정에 일부포함되어 있거나 심화된 내용이었다. 불일치 유형에 따라 질문은 분류하면, 지식 충돌에 의한 질문보다 지식 결핍에 의한 질문 빈도가 89.5%로 높게 나타났으며, 지식 결핍 유형 중 현상의 원인에 대한 설명 요구 유형이 45.9%로 질문도 가장 많고, 답변의 정확도도 가장 낮았다. 이를 통해 초등예비교사의 지식 결핍에 의한 인지적 불일치가 해소될 수 있도록 초등교육과정에 현상 중심으로 제시되어 다루지 않는 개념이라도 교사가 알아야 할 개념은 교사용 지도서의 내용을 보강할 필요가 있다는 것을 확인하였다. 또한 교과서에 제시된 실험을 현장의 상황에 맞게 재구성할 때 정확한 실험이 이루어질 수 있도록 실험 설정의 이유와 실험 도구의 작동 원리에 대한 추가 설명을 지도서에 포함해야 할 필요가 있다는 것을 확인하였다. 지식 충돌에 의한 불일치는 현실에서 경험하는 것과 교과용 지도서에 제시된 내용이 충돌하여 생기는 사례가 많았다. 따라서 이를 해소하기 위해 우리 삶의 실제 맥락과 교과서 맥락에 대한 차이를 교사용 지도서에 포함하여 교사용 지도서 텍스트와 초등예비교사의 지식 사이의 불일치를 줄일 필요가 있다.

• 한국초등과학교육학회지:초등과학교육
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• 제40권1호
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• pp.100-112
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• 2021

Based on the importance of visual representation for scientific understanding, this study applied visual thinking in elementary science classes. This study analyzed elementary students' visual thinking and investigated the instructional influences. Students' perceptions on the class applying visual thinking were also investigated. The subject were 38 fourth grade students, 18 in experimental group and 20 in control group. For the unit of 'Shadow and mirror', on-line and off-line blended classes were applied in both group because of COVID-19. The experimental group student were asked to construct their own visual thinking, while the control group students used traditional workbook. The results were as follows. First, students' visual thinking can be classified into three different types, which are 'activity recall type', 'result summary type', and 'core concept representation type' based on what they represent rather than how they represent. Second, applying visual thinking in science class showed significant effects on science academic achievement, science related attitude, and creative academic efficacy. Third, students' perceptions on applying visual thinking in science classes were very positive. Students perceived visual thinking activities were interesting and helpful for understanding science. Educational implications of applying visual thinking in elementary science classes were discussed.

• Journal of Biosystems Engineering
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• 제40권1호
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• pp.19-27
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• 2015

Purpose: A system to measure the visibility of agricultural tractor operators was designed and evaluated according to ISO standards, and a blind area diagram around the tested tractor was created based on the manual method recommended by the National Institute for Occupational Safety and Health (NIOSH). Methods: A visibility measurement system was designed and evaluated based on the ISO 5006 and ISO 5721-1 standards. Two bulbs used to simulate the operator's eyes were mounted on a bar with a supporting frame. A wooden frame was used to determine the seat index point position. The 12-m visibility test circle was divided into six sectors of vision, and the test tractor was placed at the center of the circle. Artificial light was supplied in the darkened environment, and shadow or masking effects were measured manually around the 12-m circle. Results: When the bulbs were placed at the operator's eye level, front visibility was good; no masking was found in the "A" vision sector, but larger masking widths were found in the "B" and "C" vision sectors. Since the masking width exceeded 700 mm, additional tests, such as movement of the light sources to both sides of the operator's eye level, were performed. Less than six masking effects were found in the semi-circle of vision to the front, and more than one masking was found in the "B" and "C" visual fields. The minimum distance between the centers of two masking effects exceeded 2500 mm when measured as a chord on the semi-circle of vision. A blind area diagram was created to define the exact nature of the blind spots and mirror visibility. Conclusions: Visibility evaluation is an effective way to enable proper and safe operation for agricultural tractor operators. Inclusion of this visibility evaluation test in the general testing process might aid tractor manufacturers.

• 한국실내디자인학회논문집
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• 제27호
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• pp.20-27
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• 2001

The tendency of formalization in Contemporary Architecture deeply relies on the thought of Western Philosophy, which emphasizes the art of image perceived visually but ignores the body and perception of a human beig who uses the architecture and lives in it. On the contrary, Merleau-Ponty asserted long time ago that the world and the body are inseparably related to each other. The phenomenology is important in Architecture, since the center of thought should be taken back to the human body if a artistic meaning can be obtained by Architecture. From this point of view, the meaning of Contemporary Architecture can be renewed by the phenomenological idea of Merleau-Ponty as a means of expanding thought that overcomes the limit of formalization in Contemporary Architecture. This research aims to ream from Steven Holl's work, and show the Architectural elements that are used for preceptual experience of phenomenon and the function of those element sin Architectural space of his works. The result of study on about the phenomenal light and water in Architectural space of Steven Holl is as follows; First, in perceptional experience of phenomenon, time is an important element, which is successive and make a field that cause perceptional experience. Second, light, as a phenomenological element, acted as a means of expressing the comparison and change of light and shadow in Architectural space and showing the change of color by the diversity of time in inner space. Third, water, as a phenomenal lens, not only acted functional but also functioned as an element of sensual experience in Architectural space. It acted as an image containing time, space, just like a mirror that reflect the environment.