• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.248-254
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• 2013

In location finding system using spaced multi-sensor, there is the phenomenon that the position estimation accuracy is degraded by the location of signal sources and the sensors. This phenomenon is called GDOP(Geometric Dilution Of Precision) effect. and to minimize these effects, research is needed on how. In this paper, I will describe how to minimize GDOP effect, estimating possibility of GDOP using AOA(angle of arrival) information of spaced multi sensors, and removing sensor error factor in position estimation.

• KAPE Magazine
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• s.254
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• pp.13-14
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• 2017

인천광역시 북서부에 위치한 강화군은 한국에서 다섯 번째로 큰 섬인 강화도가 있다. 사면이 바다로 둘러싸인 섬으로 그곳에 위치한 우성한우농장을 방문하여 강화도의 바닷바람으로 키우고 있는 박종덕 대표의 한우들을 보고 왔다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.184-188
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• 1999

최근 산업이 발달함에 따라 영상처리 기술이 산업에 많이 응용되고 있으며, 특히 비젼 어플리케이 션과 여러 멀티미디어 어플리케이션 분야에서, 주어진 영상에서 원하는 물체에 대한 위치정보를 빠른 시간으로 검출하는 방법에 관한 연구가 많이 진행되고 있다 특히 CCD카메라로부터 얻어진 영상 정보를 이용하여 물체의 위치정보와 물체의 패턴 분류 및 특징 추출 등 여러 가지로 응용하고 있다. 물체의 위치를 검출함에 있어서 최근까지의 방법들은 원하는 물체를 찾기 위하여 영상의 모든 부분을 비교 영역으로 정하여 물체를 찾는 방법을 이용하고 있다. 본 논문에서는 주어진 영상에서 물체를 찾기 위해 모든 부분을 비교하지 않고, 유전자 알고리즘과 칼라 히스토그램 인터섹션을 이용하여 물체의 대략의 위치를 찾고 그 주변에서 인접 색 히스토그램으로 물체를 정교하게 찾는 방법을 제안하였다. 제안한 방법은 인접 색 히스토그램과 칼라 히스토그램으로 단순히 영상의 모든 영역을 비교하는 방법에 비해 비교 횟수를 크게 줄이면서 원하는 물체의 위치를 정확히 찾을 수 있음을 알수 있었다.

• Geotechnical Engineering
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• v.12 no.5
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• pp.63-78
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• 1996

Various type of in-situ and laboratary tests were performed in order to evaluate the stiffness of sedimentary soft rock. In triaxial compression tests of sedimentary soft rocks, axial strains from the axial displacement of the loading piston or specimen cap conventionally were considerably larger than those measured. tocally on the lateral surfaces of specimen, due to the bedding errors at the top and bottom ends of a specimen. A local deformation transducer was used to measure axial strains free from the bedding error ranging from 0.001% to about 1%. In ultra-sonic wave tests, the elastic modulus of unconfined spec imens was smaller than that of confined specimens, due probably to microfracks. Young's modulus Ed from ultra-sonic wave tests and those at small local strains from triaxial tests were similar, both of which agreed very well with Young's modulus Er from field shear wave velocities. Young'a modulus from the field behaviour was virtually similar to that obtained by reducing Er based on the strain level-dependency of stiffness evaluated by the triaxial tests.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.130-134
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• 1996

본 논문에서는 광대역 소음원의 위치를 탐지하여 2차원 영상면에 소음원을 영상화할 수 있는 3차원 마이크로폰 배열을 제안하였다. 배열요소간의 상호상관함수가 2차원 영상면의 화소의 밝기에 대응되도록 영상함수를 유도하였으며 영상면은 사각면 및 원통면등으로 선택 가능 하도록 하여 소음원의 위치동정 해석이 용이하도록 하였다. 몇가지 소음원에 대한 수치 모의 실험결과는 제안된 배열이 소음제어 분야 등에 응용 될 수 있음을 보인다.

• The Journal of the Acoustical Society of Korea
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• v.35 no.4
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• pp.310-318
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• 2016

This study deals with a method to localize a noise source occuring in a marine vehicle in a 3D environment. Even when access to the noise source is limited for a marine vehicle, such as a ship or a submarine in operation, the signal received on a hydrophone located elsewhere contains Doppler effected noise by moving relatively. This study suggests noise localization algorithm in 3D based on Doppler effect by moving marine vehicle. Using a known source mounted on the vehicle, the noise source was estimated by reducing the range of Doppler center and closest point of approach via the least square method. The algorithm was verified through various simulations and it was shown that the noise could be localized in 3D based on Doppler effect by employing two fixed hydrophones located at the vehicle's exterior points and a known reference signal generator located somewhere on the vehicle.

• The Journal of the Acoustical Society of Korea
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• v.26 no.8
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• pp.415-425
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• 2007

This paper proposes a method of underwater source localization using the wideband interference patterns matching. By matching two interference patterns in the spectrogram, it is estimated a ratio of the range from source to sensor5, and then this ratio is applied to the Apollonius circle. The Apollonius circle is defined as the locus of all points whose distances from two fixed points are in a constant value so that it is possible to represent the locus of potential source location. The Apollonius circle alone, however still keeps the ambiguity against the correct source location. Therefore another equation is necessary to estimate the unique locus of the source location. By estimating time differences of signal arrivals between source and sensors, the hyperbola equation is used to get the cross point of the two equations, where the point being assumed to be the source position. Simulations are performed to get performances of the proposed algorithm. Also, comparisons with real sea experiment data are made to prove applicability of the algorithm in real environment. The results show that the proposed algorithm successfully estimates the source position within an error bound of 10%.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.78-84
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• 2022

In this paper, we propose a closed-form based 3D localization method in the presence of multiple signal sources. General localization methods such as TDOA, AOA, and FDOA can estimate a location when a single signal source exists. When there are multiple unknown signal sources, there is a limit in estimating the location. The proposed method calculates a cross-correlation vector of signals received by sensors having an array antenna, and estimates TDOA and AOA values from the cross-correlation values. Then, the coordinate transformation is performed using the position of the reference sensor. Then, the coordinate rotation is performed using the estimated AOA value for the transformed coordinates, and then the three-dimensional position of each emitter is estimated. The proposed method verifies its performance through computer simulation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.407-408
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• 2011

본 논문에서는 현재 생산하고 있는 흉부 촬영 장치의 위치제어 기능을 개선하는 제어모듈의 개발에 대해 논하였다. 현재 생산되고 있는 흉부 촬영 장치는 스위치를 수동으로 조작하여 촬영에 적당한 위치에 도달하였을 때 멈춘 후 촬영을 하고 있다. 그러나 이 방식은 원하는 위치에 정확히 위치시키기 위해서는 원하는 위치가 될 때까지 스위치 조작을 반복하여야 한다. 따라서 단 한 번의 스위치 버튼을 누르기만 하면 정확한 위치에 도달하도록 스위치 모듈과 제어장치 모듈의 기능을 개선시켜 위치 설정을 위한 조작 시간을 줄이고 사용의 편의성을 향상시켜 업무의 효율성을 기할 수 있도록 하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.337-340
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• 2011

In location finding system using spaced multi-sensor, Depending on the signal source's location and the location of the sensors Position estimation accuracy is determined. This phenomenon is called GDOP effect. and to minimize these effects, research is needed on how. In this paper, I will describe how to minimize GDOP effect, estimating GDOP using angle of arrivals of multi sensors, and removing sensor error factor.