• Journal of electromagnetic engineering and science
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• 제14권2호
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• pp.79-81
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• 2014

In B-scan data measured by a pulse-type monostatic borehole radar, target signatures are seriously obscured by two clutters that differ in orientation and intensity. The primary clutter appears as a nearly constant time delay, which is caused by internal ringing between antenna and transceiver in the radar system. The secondary clutter occurs as an oblique time delay due to the guided borehole wave along the logging cable of the radar antenna. This issue led us to perform adaptive filtering processing for orientation-based clutter removal. This letter describes adaptive filtering processing consisting of a combination of edge detection, data rotation, and eigenimage filtering. We show that the hyperbolic signatures of a dormant air-filled tunnel target can be more distinctly enhanced by applying the proposed approach to the B-scan data, which are measured in a well-suited test site for underground tunnel detection.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.566-569
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• 1993

This paper presents the design and implementation of an industrial controller for an autonomous guided vehicle(AGV) with economic sensor. A guidance scheme provides accurate tracking and achieves faster minimizing oftracking error. A sensor at the center provides the position and orientation of the vehicle relative to the track. Control laws that make use of this information have been devised to achieve accurate and fast tracking. The gains are modified on-line to achieve proper tracking. The simulation and implementation results are provided for the illustration of the implemented controller.

• 한국학교수학회논문집
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• 제18권1호
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• pp.39-60
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• 2015

본 논문에서는 van Hiele의 단계적 교수법에 근거한 예비교사들의 수학 수업에서 학생들을 지식 구성의 주체로 만드는 탐구 활동의 활성화 방안을 탐색하고자 한다. 이를 위하여 예비교사들의 수업 지도안과 수업 시연에서 van Hiele의 단계적 교수법의 정보 단계와 안내된 탐구단계에서의 교수 학습 상황을 분석한다. 이와 같은 교수 학습 상황에서 탐구학습 또는 발견학습의 활성화 가능성을 탐색한다. 특히, 본 연구에서 삼각형의 외심과 내심을 두 도형의 위치관계라는 개념구조 안에서 삼각형과 원의 위치관계를 출발점으로 설정하는 방안을 제안하고 이 제안에 대한 구체적인 실행 방법으로서 "사실1: 삼각형의 외접원은 유일하게 존재한다."와 "사실2: 삼각형의 내접원은 유일하게 존재한다."는 두 가지 사실의 도입과 증명을 van Hiele의 단계적 교수법에 근거한 새로운 지도방법으로 제시하고자 한다.

• Journal of Mechanical Science and Technology
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• 제15권8호
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• pp.1097-1107
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• 2001

In this paper, the wall following navigation algorithm of the mobile robot using a mono vision system is described. The key points of the mobile robot navigation system are effective acquisition of the environmental information and fast recognition of the robot position. Also, from this information, the mobile robot should be appropriately controlled to follow a desired path. For the recognition of the relative position and orientation of the robot to the wall, the features of the corridor structure are extracted using the mono vision system, then the relative position, the offset distance and steering angle of the robot from the wall, is derived for a simple corridor geometry. For the alleviation of the computation burden of the image processing, the Kalman filter is used to reduce search region in the image space for line detection. Next, the robot is controlled by this information to follow the desired path. The wall following control scheme by the PD control scheme is composed of two control parts, the approaching control and the orientation control, and each control is performed by steering and forward-driving motion of the robot. To verify the effectiveness of the proposed algorithm, the real time navigation experiments are performed. Through the result of the experiments, the effectiveness and flexibility of the suggested algorithm are verified in comparison with a pure encoder-guided mobile robot navigation system.

• 4차산업연구
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• 제2권1호
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• pp.33-43
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• 2022

Purpose - With the rapid development of information technology, the digital economy has become an important grip of the new development pattern, and the digital transformation of enterprises is a major trend. As SMEs are the mainstay of the economy and employment, it is important to study the digital transformation of SMEs to promote the development of the digital economy. Research design, data, and methodology - Based on a resource-based view, this report analyses the current situation and issues of digital transformation of SMEs from the perspective of digital orientation as well as the breadth and depth of technological capabilities of enterprises, using data from a survey of 200 manufacturing enterprises in China. Result - The results show that SMEs generally have a digital transformation mindset, but a weak digital foundation. In order to execute a digital strategy, companies need digital transformation capabilities. These behavioral capabilities are guided by the strategic direction of the business, and companies with strong capabilities are always trying to tap into the full digital potential. Conclusion - In order to effectively promote the digital transformation of SMEs, we suggest that SMEs pay attention to digital capability building, make good use of digital platforms and network resources, and lay a solid foundation for digital transformation; meanwhile, we suggest that government departments play a guiding and supporting role to build a cross-industry and cross-sector digital synergy system to help promote the development of SMEs' digital transformation. This paper presents some suggestions from both the internal and external environment of the enterprise, with the expectation of contributing to the digital transformation practices of SMEs.

• Composites Research
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• 제22권4호
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• pp.33-40
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• 2009

유리섬유/에폭시 복합재료로 피막한 판유리의 표변파괴거동에 대한 섬유방향효과를 미소강구 충격실험을 통해 연구했다. 본 연구에서는 단순소다유리판(soda-lime glass plates), 일방향 유리섬유/에폭시박막 (glass/epoxy lamina ply)을 1층 및 2층 접착, 직교형 유리섬유/에폭시 박막 (2층)을 접착한 4종류의 시편을 사용하였다. 유리판 배면에 스트레인게이지를 부착하여 충격중의 최대 응력과 흡수파괴에너지를 측정하였다. 피막없는 판유리의 경우 충격속도 증가에 따라 링균열, 콘균열, 레이디얼 균열이 충격표면부에서 발생하였다. 복합재료 박막으로 피막한 결과, 소다유리판의 균열은 현저히 감소하였으며 섬유층과 판유리사이의 박리 및 소성변형영역의 방향은 섬유방향으로 진행했다. 최대응력과 흡수파괴에너지를 이용하여 구한 충격 표면파괴지수는 표면저항의 효과적인 평가지수로서 사용될 수 있었다.

• 인지과학
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• 제34권2호
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• pp.85-110
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• 2023

타인의 시선 방향과 시각적 표적이 나타나는 위치가 일치할 때 표적에 대한 탐지가 빠르고, 정확해지는 것을 시선 단서 효과(gaze cueing effect)라 한다. 시선 단서는 얼굴의 방향(orientation)에 의해 영향 받을 수 있는데, 얼굴이 똑바로(upright) 제시될 때는 강력한 시선 단서 효과가 나타나지만 얼굴이 180° 회전되어 거꾸로(inverted) 제시될 때는 일부 연구에서만 유의한 시선 단서 효과가 보고되었다(예, Tipples, 2005). 본 연구는 얼굴의 위아래가 거꾸로 제시될 때 시선이 주의를 유도하는 단서로 작동할 수 있는지 재확인하고, 얼굴의 방향 뿐 아니라 배경의 방향, 시선 단서와 표적 간의 시간 간격(SOA) 등 시선 단서에 영향을 미칠 수 있는 변인들을 체계적으로 조작하여 시선 단서의 효과를 살펴보고자 하였다. 실험 결과, 선행 연구와 달리 거꾸로 된 얼굴에서도 유의한 시선 단서 효과가 관찰되었으며, 이러한 결과는 배경이 없거나(실험 1), 배경이 있을 때(실험 2와 3) 모두 일관되게 관찰되었으며, 얼굴과 배경의 방향 간 상호작용은 유의하지 않았다. 또한 SOA가 짧을 때(150 ms) 모든 얼굴과 배경 방향 조건에서 유의한 시선 단서 효과가 관찰되었으나, SOA가 길 때는(1000 ms) 시선 단서 효과가 유의하지 않았다. 본 연구는 거꾸로 된 얼굴에서도 비교적 짧은 SOA 조건의 경우(150 ms) 유의한 시선 단서 효과가 일관적으로 관찰됨을 보여줌으로써 과거 거꾸로 된 얼굴에서 유의한 시선 단서 효과를 얻지 못했던 일부 연구 결과의 신뢰도와 반복 관찰 가능성에 의문을 제기함은 물론, 얼굴과 배경의 다양한 방향에서도 시선이 향하는 방향으로 주의가 유도될 수 있음을 보여주는 추가적 증거를 제공했다는 점에서 의미가 있다.

• 제어로봇시스템학회논문지
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• 제9권2호
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• pp.152-158
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• 2003

A machine-vision guided inspection system with go-no gauges for inspecting eggcrate assemblies in steam generators is considered. To locate the gauge at the right place, periodic corrective actions for its position and traveling direction are required. We present a machine vision algorithm for determining inserting position and traveling direction of the go-no gauge. The overall procedure of the algorithm is composed of camera calibration, eggcrate image preprocessing, grid-height adjustment, intersection point estimation between two intersecting grids, and adjustment of position and traveling direction of the gauge. The intersection point estimation is performed by using linear regression with a constraint. A test with a real eggcrate specimen shows the feasibility of the algorithm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.423-427
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• 2004

In this work, we propose a new ultrasonic damage inspection method in plate structures. The proposed method employs an OPMT (Orientation-adjustable Patch-type Magnetostrictive Transducer) in order to make the ultrasonic waves focused on the specific target point. For experiments, virtual grid points were set up at every 50 mm in an aluminum plate and two OPMTs were used for inspection. If there exists a crack in a plate, the reflected Lamb wave from the crack is measured in addition to the direct waves from the transmitting transducer to the receiving transducer.

• 한국수학교육학회지시리즈A:수학교육
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• 제48권1호
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• pp.1-20
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• 2009

The study was to investigate an effect of students' learning for enhancing spatial ability, using a geometric manipulative recently designed. A mixed methodology was chosen to achieve the purpose of the study. To find students' achievement, 152 of the 8th graders in Kyunggi Do participated in data collection. At the same time. students' performance of the class was videotaped and analyzed to see students' responses, The results showed that the effect of using the manipulative was statistically significant at level, p<.05 to enhance the spatial ability. Specifically, in comparison of each component. spatial orientation was more effective than spatial visualization. In the spatial orientation, the part of field was more effective than the reorganized whole. It showed that students were given more opportunities to find mathematical properties and relations between 2nd and 3rd-dimensional figures through their intuitive observation, and also the manipulative helped the students find the property of the part of field because it gave an easy way to manipulate the property of the find parts of whole which was composed of the frame of the solid figures without surfaces. In using the manipulative, students were very flexible in finding the number of plane figures, but the relations between the 2nd and 3rd dimensional figures need to be clearly guided in consideration of the characteristics of the manipulative, based on the definitions of geometric properties(cf. points can make lines, not surfaces directly).