• 산업기술연구
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• 제20권A호
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• pp.17-26
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• 2000

To determine the source location of acoustic emission in rock, the least square method has been used until lately but it needs much time and efforts. In this study, neural network system is applied to above model instead of least square method. This system has twenty seven input processing elements and three output processing element. The source locations calculated by above two methods are similarly concordant. The new method using neural network system is relatively simple and easy for calculating source location compared with traditional method.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.363-370
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• 2003

The object of this study is to investigate the effect of compounded welding by using an acoustic emission (AE) signals and doing a source location for weld heat affected zone (HAZ) through tensile testing. This study was carried out a SM 490A high tension steel for electronic shielded metal arc welding (SMAW), $CO_2$ gas arc welding and TIG welding. Data displays are based on the measured parameters of the AE signals, along with environmental variables such as time and load. These history plots are displays showing the chronological course of the test. Also, source location gives the X- and Y-coordinates of the AE source.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.467-469
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• 2001

This paper presents an efficient location estimation methodology for a partial discharge(PD) source in the power transformer. The methodology previously proposed is not suitable for locating a PD source because the ultrasonic signal with medium attenuated through the inner structure. In general, the propagation characteristic of ultrasonic signal with medium is different. Therefore, using this propagation characteristic, we can detect the location of PD source. In this paper, the proposal algorithm finds the PD source using three sensors attached to one side of the transformer without attenuation of the ultrasonic signal and applying the neural network based geometrical method. The proposed methodology demonstrates the effectiveness and validity on an experimental transformer.

• 로봇학회논문지
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• 제9권4호
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• pp.206-215
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• 2014

Acoustic signal is crucial for the autonomous navigation of underwater vehicles. For this purpose, this paper presents a method of acoustic source localization. The proposed method is based on the probabilistic estimation of time delay of acoustic signals received by two hydrophones. Using Bayesian update process, the proposed method can provide reliable estimation of direction angle of the acoustic source. The acquired direction information is used to estimate the location of the acoustic source. By accumulating direction information from various vehicle locations, the acoustic source localization is achieved using extended Kalman filter. The proposed method can provide a reliable estimation of the direction and location of the acoustic source, even under for a noisy acoustic signal. Experimental results demonstrate the performance of the proposed acoustic source localization method in a real sea environment.

• 한국전자통신학회논문지
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• 제8권3호
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• pp.379-387
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• 2013

대규모 무선 센서 네트워크에 있어서 광역도청에 대응하여 통신 근원지와 도착지의 위치기밀을 유지하기 위해서는 흔히 과다한 더미패킷들이 발생된다. 앞서의 연구에서는 데이터패킷 전송 동안에 근원지와 도착지를 포함하는 일정 범위 내의 노드들만이 빈 타임-슬롯마다 더미패킷을 발생하도록 하는 위치보안 라우팅 프로토콜 ELPR(End-node Location Privacy Routing)을 제안하였다. 이 논문에서는 고정된 보안성을 갖는 PCM(Periodic Collection Method)에 비해 ELPR은 다양한 위치보안 수준을 제공함을 보였다. 시뮬레이션을 통해 ELPR은 노드들의 수나 데이터패킷들이 많은 경우, PCM보다 발생 패킷 수에 있어서 경제성 있는 위치보안이 가능함을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.483-489
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• 2009

The Time Difference of Arrival (TDOA) algorithm is being used widely for identifying the location of a source emanating either electrical or acoustic signal. It's application areas will not be limited to identifying the source at a fixed location, for example the origin of an earthquake, but will also include the trajectory monitoring for a moving source equipped with a GPS sensor. Most of the TDOA algorithm uses time correlation technique to find the time delay between received signals, and therefore difficult to be used for identifying the location of multiple sources. In this paper a TDOA algorithm based on cross-spectrum is developed to find the trajectory of two sound sources with different frequencies. Although its application is limited to for the sources on a disk plane, but it can be applied for identifying the locations of more than two sources simultaneously.

• 방송공학회논문지
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• 제10권3호
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• pp.328-338
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• 2005

멀티채널 오디오 컨텐츠에 대한 사용자의 욕구가 증가하고 있는 가운데 서비스를 위한 저비트율 멀티채널 오디오 부호화 기술에 대한 표준화가 진행되고 있다. 본 논문에서는 협대역폭 채널환경에 적합한 고압축율의 멀티채널 오디오 부호화 기술인 음원위치단서 부호화 기술(Sound Source Location Cue Coding; SSLCC)을 제안하고, SSLCC가 기존 BCC (Binaural Cue Coding)의 압축 성능을 향상시키기 위하여 단서로 이용한 VSLI (Virtual Source Location Information)를 설명한다. 또한 객관적 평가로 기존의 BCC 시스템과의 평균 비트율을 비교하고, MUSHRA (Multi-Stimulus test with Hidden Reference and Anchor) 방법을 이용한 주관 청취 평가를 수행하여 제안된 SSLCC 부호화 기법의 우수성을 확인하였다.

• ETRI Journal
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• 제28권2호
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• pp.219-222
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• 2006

Virtual source location information (VSLI) has been newly utilized as a spatial cue for compact representation of multichannel audio. This information is represented as the azimuth of the virtual source vector. The superiority of VSLI is confirmed by comparison of the spectral distances, average bit rates, and subjective assessment with a conventional cue.

• 한국공작기계학회논문집
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• 제13권5호
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• pp.87-95
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• 2004

From the results of AE(Acoustic Emission) source location occurred by the spot exciting as suggested in this research, it has been confirmed that AE technique is quite fruitful in figuring out the location of the occurrence, form, size and direction of the defects. As the results of examining the distribution of event for the angle of crack $\alpha$ to Xs and Ys, as the increases from $0^{\circ}$ ~ $90^{\circ}$, gradually changes its width from the axis Xs to the axis Ys. So event appears approximately similar in its size at the angle of crack $\alpha$=$45^{\circ}$, yet opposite when $\alpha$ is lager. It is believed that this is a phenomenon where its crack legnth $\alpha$, assumed as a planar defect, is to be prcjected toward the direction with a larger size. Thus, it is expected that the application of the experimental method suggested in this study would make it possible to identify the location of the defect in the material in the nondestructive way.

• 비파괴검사학회지
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• 제36권5호
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• pp.391-398
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• 2016

음향방출기법은 구조물에 존재하는 손상 및 손상 메커니즘을 규명하는 가장 유효한 비파괴검사 수단으로 널리 이용되고 있다. 그러나 기존의 손상위치표정 기법은 탄성파 전파 속도에 크게 의존하는 기법의 한계에 의하여 복합재료 또는 이종의 재료로 구성된 구조물에서의 손상을 탐지하기 어려운 한계점을 가지고 있다. 최근 다양한 분야에서 사용되고 있는 압축천연가스(CNG) 저장용기는 무게와 강성의 효율을 위하여 복합재료를 사용하여 외부를 보강하는 새로운 형태의 구조를 사용하고 있다. 이러한 다층 복합소재의 사용으로 기존의 손상탐지기법으로는 저장용기의 외부에서 가해지는 충격 혹은 결함에 의한 저장탱크에 발생한 손상의 측정이 매우 어렵게 되었다. 이러한 한계를 극복하기 위하여 본 연구에서는 선행연구를 통하여 개발된 에너지 기반 contour D/B map 기법을 이용하여 4 가지 형식의 CNG 저장탱크에 발생한 외부 충격 신호의 손상 위치를 측정하였다. 각각의 형식의 저장탱크에서 측정된 손상 위치 결과를 비교 분석하여 새로운 기법의 측정 성능을 알아보았다.