• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1738-1741
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• 1997

This paper addresses the issue fo target classification and localization with a SONAR for mobiler robot indoor navigation. In particular, multiple refetions of SONAR sound are used actively and interntionally. As for the SONAR sensor, the multiple reflection has been generally considered as one of the noisy phenomena, which is inevitable in the indoor environments. However, these multiple reflections can be a clue for classifying and localizing targets in the indoor environment if those can be controlled and used well. This paper develops a new SONAR sensor module with a reflection plane which can actively create the multiple refection. This paper also intends to suggest a new target classification emthod which uses the multiple refectiions. We approximate the world as being two dimensional and assume that the targets consisting of the indoor environment are pland, corner, and edge. Multiple reflection paths of an acoustic bean by a SONAR are analyzed, by simulations and the patterns of the TOPs (Time Of Flight) and angles of multiple reflections from each target are also analyzed. In addition, a new algorithm for target classification and localization is proposed.

• 제어로봇시스템학회논문지
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• 제8권7호
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• pp.564-572
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• 2002

This article describes the ultrasonic range sensor for the recognition of the Indoor environment, especially utilizing the multiple reflection properties of the sonar usually ignored as disturbances or noises. In this paper, we endow the ultrasonic range sensor with the active motion using the stepping servomechanism in order to get the multiple reflections with environment objects. Environment features such as target type, distance and azimuth based on the scanned one frame data of that multiple reflection patterns are recognized simultaneously.

• 제어로봇시스템학회논문지
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• 제10권9호
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• pp.779-784
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• 2004

This paper describes a sonic polygonal multiple reflection range sensor (SPMRS), which uses multiple reflection properties usually ignored in ultrasonic sensors as disturbances or noises. Targets such as a plane, corner, edge, or cylinder in indoor environments can easily be detected by the multiple reflection patterns obtained with a SPMRS system. Target classification and feature data extraction, such as distance and azimuth to the target, are computed simultaneously by considering the geometrical relationships between the detected targets, and finally the environment model is generated by refining the detected targets. In addition, the narrow field of view of a sonar range sensor is increased and the scanning time is reduced by active motion of the SPMRS stepping servomechanism.

• Smart Structures and Systems
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• 제8권2호
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• pp.219-237
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• 2011

This paper presents novel research into the source localization of multiple impacts. Source localization technology for single impact loads in a plate structure has been used for health monitoring. Most of research on source localization has been focused only on the localization of single impacts. Overlapping of dispersive waves induced by multiple impacts and reflection of those waves from the edge of the plate make it difficult to localize the sources of multiple impacts using traditional source localization technology. The method solving the overlapping problem and the reflection problem is presented in the paper. The suggested method is based on pre-signal processing technology using band pass filter and optimal filter. Results from numerical simulation and from experimentation are presented, and these verify the capability of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.830-835
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• 2003

This paper describes a sonic polygonal multiple reflection range sensor (SPMRS), which uses multiple reflection properties usually ignored in ultrasonic sensors as disturbances or noises. Targets such as a plane, corner, edge, or cylinder in indoor environments can easily be detected by the multiple reflection patterns obtained with a SPMRS system. Target classification and feature data extraction, such as distance and azimuth to the target, are computed simultaneously by considering the geometrical relationships between the detected targets, and finally the environment model is generated by refining the detected targets. In addition, the narrow field of view of a sonar range sensor is increased and the scanning time is reduced by active motion of the SPMRS stepping servomechanism.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.141-142
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• 2008

In order to develop a simple ray tracing model for simulating the radiation pattern of a LED, the propagation of a ray within the LED capsule was systematically evaluated by considering refraction and reflection from the capsule-air interface, multiple reflection within the capsule, and total internal reflection at the boundary. It was found that concentric ring shapes on the radiation pattern was formed by the rays multiple-reflected from the capsule surface, and that the strength of these rays were decreased rapidly as the number of multiple reflection is increased.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권2호
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• pp.104-109
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• 2010

조명반사 문제는 영상 분석에서 흔히 존재하는 문제점이며, 영상 분석에서 필요로 하는 주요 특징들을 검출하는 데 많은 어려움을 야기한다. 특히 이러한 문제점은 야간이나 우천 시에 더욱 두드러지는 것으로 알려졌다. 본 논문에서는 조명 반사에 의해 특징 분석이 어려운 영역에서 조명 반사를 제거하거나 반사되지 않은 상태로 복원하는 것을 목표로 한다. 본 논문에서는 다중 영상에서 획득된 다중 기하정보를 이용한 3차원 공간 분석과 기하학적 접근을 시도한다. 이러한 방법들에서 얻어진 정보들을 바탕으로 조명 반사가 이루어지는 영상들을 조합하여 조명 반사를 제거하는 방법을 제안한다. 조명 반사 영역을 제거하기 위하여 영상 내에서 조명 및 반사영역을 수직 히스토그램의 국부 최대값을 이용하여 추출한다. 이 후, 각 영상 내에서 도로 표면에 해당하는 영역을 추출하기 위해서 필요한 기본 행렬과 상동 관계 행렬을 다중 영상들의 대응점들을 분석하여 계산한다. 이렇게 얻어진 각 영상들의 도로표면을 기준 영상에 배치하여, 양쪽 영상에서 조명 반사가 상대적으로 적은 영역을 선택하는 방법을 취한다. 이러한 과정에 의하여 중복되지 않는 도로표면의 반사는 효과적으로 감소되었으며 도로가 가지고 있는 고유한 정보 또한 손실되지 않았다. 수집된 데이터를 이용하여 실험한 결과는 계산 속도에 비하여 뛰어난 성능을 보여주었으나 기하학적 공통 영역 부분의 복원은 상대적으로 부족한 것으로 판단되었다.

• 대한기계학회논문집
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• 제12권3호
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• pp.440-449
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• 1988

본 연구에서는 미소한 진동진폭의 정밀한 측정을 위해 비교적 광선정렬(opti- cal alignment)이 쉽고 광손실이 적으며 국소부위의 진동측정이 가능한 다중반사계를 Michelson간섭계에 도입하였다.미소 진동진폭의 정밀한 값을 결정하기 위해서는 간 섭신호를 측정하여 간섭무늬 보간법과 곡선 맞춤법을 이용하는 방법이 있다. 전자는 간단한 계산과 시간을 절약할 수 있는 반면 후자는 복잡한 계산으로 인해 많은 시간이 소요된다. 그러나 정밀계측장비의 교정에서와 같이 경우에 따라서는 많은 시간과 노 력이 소요되더라도 정밀한 측정결과를 얻어야할 필요가 있기 때문에 이들 두가지 방법 의 정밀도를 확인하기 위해 컴퓨터에 의한 모의실험을 수행하였다.

• ETRI Journal
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• 제35권6호
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• pp.1148-1151
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• 2013

We propose a way to measure the absorber reflectivity at a low cost. Only one simple antenna with a small radiating aperture and a frequency-domain instrument are utilized. The previously used equation for calculating the reflectivity of an absorber is inaccurate, and, therefore, a new equation is derived based on multiple reflection analysis and three test models. Notably, the reflection coefficient of the antenna is included in the derived equation. The accuracy of the proposed method is proven through simulation and measurements. It can be easily applied to a product examination by absorber manufacturers and customers owing to its advantages of simplicity, cost effectiveness, and non-cutting examination.

• ETRI Journal
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• 제34권6호
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• pp.954-957
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• 2012

Titanium foils for use in photoelectrochemical devices are treated with a $HNO_3$-HF solution. After this treatment, the optical reflection characteristics of the Ti substrates are markedly increased in terms of not only reflectivity but also optimized wavelength. Furthermore, the "multiple beam interference" theory and optical analysis of surface morphologies clearly verify the origin of the optimized optical reflection properties.