• Title/Summary/Keyword: 음향 탐지

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Ship Radiated Noise Measurement, Analysis and Prediction (선박 방사소음의 측정, 분석 및 예측)

  • 윤종락;김천덕;하강열
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.524-532
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    • 1997
  • 수중음향표적 특히 선박방사소음을 탐지하거나 식별하는 군사적 목적의 수동소나는 수중청음기 배열로 구성되며 각 배열센서에 수신된 신호에 배열 신호처리기술을 적용하여 선박의 거리, 방위 탐지는 물론 선박의 음향적 특징을 식별하는 고도의 음향장치이다. 그러나 이러한 장치운용자의 선박탐지, 식별이나 새로운 수동소나 개발, 나아가 스텔스 능력의 선박 설계를 위해서는 선박방사소음의 측정, 분석 및 예측에 관한 이해가 선행되어야 할 것이다. 본 연구는 대표적인 선박방사소음 측정시스템의 소개, 방사소음발생기구, 측정자료의 분석 및 예측에 관한 기초기술을 연구 분석한 내용이다.

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함정 음향 시험평가 기술 현황

  • Kim, Jong-Chul;Son, Kwon;Lee, Pil-Ho
    • Journal of KSNVE
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    • v.12 no.6
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    • pp.429-436
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    • 2002
  • 함정에 있어서 수중 표적의 탐지나 식별, 피탐 위험으로부터 회피 등은 함정의 생존성과 직결되는 사항으로 방사소음을 최소화하는 함정 음향 스텔스가 중요한 요소이다. 함정의 음향분야 시험평가 결과는 신조함정의 기준 만족도 평가뿐만 아니라 음향식별 정보추출/DB구축, 소음통제 방안설정 및 피탐지 위험성 평가 등 전반적인 음향작전 능력 향상에 활용되고 있다.(중략)

Detection of Signal Frequency Lines for Acoustic Target using Autoassociative Momory Neural Network (자동 연상 기억장치 신경망을 이용한 음향 표적의 신호 주파수선 탐지)

  • Lee, Sung-Eun;Hwang, Soo-Bok;Nam, Ki-Gon;Kim, Jae-Chang
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.5
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    • pp.118-124
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    • 1996
  • Signal frequency lines generated from the acoustic targets are of particular importance for target detection and classification in passive sonar systems. The underwater noise consists of a mixture of ambient noise and radiated noise of targets. Detction of exact signal frequency lines depends on signal detection threshold and variation of ambient noise. In this paper, a detection method of signal frequency lines for acoustic targets using autoassociative memory (ASM) neural network, which is not sensitive to variation of signal detection threshold and ambient noise, is proposed. It is confirmed by simulation and application of real acoustic targets that the proposed method shows good performance for detection of signal frequency lines.

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Detection Performance Analysis of Underwater Vehicles by Long-Range Underwater Acoustic Communication Signals (장거리 수중 음향 통신 신호에 의한 수중 운동체 피탐지 성능 분석)

  • Hyung-Moon, Kim;Jong-min, Ahn;In-Soo, Kim;Wan-Jin, Kim
    • Journal of the Korea Society for Simulation
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    • v.31 no.4
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    • pp.11-22
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    • 2022
  • Unlike a short-range, a long-range underwater acoustic communication(UWAC) uses low frequency signal and deep sound channel to minimize propagation loss. In this case, even though communication signals are modulated using a covert transmission technique such as spread spectrum, it is hard to conceal the existence of the signals. The unconcealed communication signal can be utilized as active sonar signal by enemy and presence of underwater vehicles may be exposed to the interceptor. Since it is very important to maintain stealthiness for underwater vehicles, the detection probability of friendly underwater vehicles should be considered when interceptor utilizes our long-range UWAC signal. In this paper, we modeled a long-range UWAC environment for analyzing the detection performance of underwater vehicles and proposed the region of interest(ROI) setup method and the measurement of detection performance. By computer simulations, we yielded parameters, analyzed the detection probability and the detection performance in ROI. The analysis results showed that the proposed detection performance analysis method for underwater vehicles could play an important role in the operation of long-range UWAC equipment.

Effects of Wind-Generated Bubbles on Sound Propagation (음파전달에 미치는 풍성기포의 영향)

  • Lee, Won-Byoung;Kim, Young-Shin;Joo, Jong-Min;Lee, Chang-Won;Na, Jung-Yul
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.8
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    • pp.395-402
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    • 2006
  • When an active SONAR works in the subsurface. its detection Performance is limited by the reverberation. The winds Play a primary role in the Production of bubbles in the ocean. And the bubbles as efficient scatters contribute to the reverberant field. In this Paper the effects of wind-generated bubbles on sound propagation in the subsurface are investigated as a mid-frequency Hull-mounted SONAR works. The active signal excess is calculated at source depths 3. 5. and 10m considering bubble layer for frequencies 5. 7.5, and 10kHz. The change of the near-surface sound speed tend to increase surface reverberation levels and change the active signal excess. In the 10m/s winds. the maximum detection range reduces over 3km through the near-surface . The reason is the upper refraction due to the wind-generated bubbles.

Estimation of Impulse Position on the Plate Using Artificial Neural Network (신경망회로를 이용할 평판의 충격위치 탐지)

  • Lee Sang-Kwon;Lee Joo-Yung;Park Jin-Ho
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.333-336
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    • 2004
  • 원자력 구조물, 항공기 구조물 등의 손상은 각 구조물의 손상에 의해서 발생하는 충격파의 탑지로서 손상의 위치를 탐지 할 수가 있다. 이러한 손상의 위치를 탐지하기 위한 역변환 문제는 오랜 기간 동안 중요한 연구의 과제가 되고 있다. 본 연구에서는 신경망 회로 기술을 이용하여 이러한 충격파를 탐지하고자 하며, 이 기술의 검증을 위해서 평판에서 실험을 실행하여 검증 하였다.

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Automatic target detection and tacking for a passive sonar system (수동소나에 적합한 자동탐지 및 추적기법 개발)

  • Seo Ik-Su;Yang In-Sic;Oh Wontchon
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.467-470
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    • 2004
  • 잠수함 정숙화 추세와 복잡한 해양 환경으로 대잠수함전에서 미약한 표적신호를 지속적으로 탐지하기 매우 어려워지고 있어 소나 운용자가 장시간 지속적으로 전방위 표적 탐색하는 부담이 매우 크므로 표적 자동탐지 추적 기능이 필수적이다. 본 논문에서는 장거리 예인 수동소나에 적합한 표적의 자동 탐지 및 추적기법을 제안하고 시뮬레이션과 실제 해상 환경에서 수중 표적신호로 성능을 검증하였다.

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능동 소나 체계에서의 표적 탐지 거리 예측 알고리즘과 응용

  • 박재은
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1993.06a
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    • pp.186-189
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    • 1993
  • 능동 소나 체계에서 표적의 탐지거리 예측을 위하여 소나방정식이 이용되는데, 이는 음원 준위, 전달 손실, 표적 강도, 복반사 준위, 소음 준위, 방향성 이득, Detection threshold, Signal excess, 탐지 확률과 탐지거리의 요소로 구성된다. 본 연구에서는 능동 소나 체계에서 소나 깊이와 표적 깊이의 함수인 탐지거리를 계산하기 위한 알고리즘에 대해 살펴보았다. 소나의 각 요소와 환경이 주어졌을 때 SAFARI 모델을 이용하여 각 수신기의 깊이와 거리에서의 전달손실을 계산하였으며, 구하여진 전달 손실과 배경 소음 준위를 이용하여 Signal excess를 계산하였다. ROC(Receiver-operating-characteristic) 곡선을 이용하여 Signal excess를 탐지 확률로 계산한 후 두 항을 곱하여 각 깊이별 거리로 적분함으로서 탐지거리를 구하였다. 주파수 30Hz의 전방향 음원을 사용하여 여름의 일반적 음속 분포에서 계산한 결과 100m 음원 보다 300m 음원에서 상대적으로 큰 탐지거리를 얻었으며 각 음원 깊이별 평균 탐지거리는 100m 이하의 표면을 제외한 500m 까지는 거의 일정함을 알 수 있었다.

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A Comparison of Bioacoustic Recording and Field Survey as Bird Survey Methods - In Dongbaek-dongsan and 1100-altitude Wetland of Jeju Island - (조류 조사 방법으로써 생물음향 녹음과 현장 조사의 비교 - 제주 동백동산과 1100고지 습지를 대상으로 -)

  • Se-Jun Choi;Kyong-Seok Ki
    • Korean Journal of Environment and Ecology
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    • v.37 no.5
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    • pp.327-336
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    • 2023
  • This study aimed to propose an effective method for surveying wild birds by comparing the results of bioacoustic detection with those obtained through a field survey. The study sites were located at Dongbaek-dongsan and a 1100-altitude wetland in Jeju-do, South Korea. The bioacoustic detection was conducted over the course of 12 months in 2020. For the bioacoustic detection, a Song-meter SM4 device was installed at each study site, recording bird songs in 1-min per hour, .wav, and 44,100 Hz format. The findings of the field survey were taken from the 「Long-term trends of Bird Community at Dongbaekdongsan and 1100-Highland Wetland of Jeju Island, South Korea.」 by Banjade et al. (2019). The results of this study are as follows. First, the avifauna identified using bioacoustic detection comprised 29 families and 46 species in Dongbaek-dongsan, and 16 families and 25 species in the 1100-altitude wetland. Second, based on the song frequency, the dominant species in Dongbaek-dongsan were Hypsipetes amaurotis (Brown-eared Bulbul, 33.62%), Horornis diphone (Japanese Bush Warbler, 12.13%), and Zosterops japonicus (Warbling White-eye, 9.77%). In the 1100-altitude wetland the dominant species were Corvus macrorhynchos (Large-billed Crow, 27.34%), H. diphone (19.43%), and H. amaurotis (16.56%). Third, in the field survey conducted at Dongbaek-dongsan, the number of detected bird species was 39 in 2009, 51 in 2012, 35 in 2015, and 45 in 2018, while the bioacoustic detection identified 46 species. In the field survey conducted in the 1100-altitude wetland, the number of detected bird species was 37 in 2009, 42 in 2012, 34 in 2015, and 38 in 2018, while the bioacoustics detection identified 25 species. Overall, 43.6% of the 78 species detected in the field survey in Dongbaek-dongsan (34 species) were identified using bioacoustic detection, and 38.3% of the 47 species detected in the field survey in the 1100-altitude wetland (18 species) were identified using bioacoustic detection. Fourth, the bioacoustic detection identified 9 families and 12 species of birds in Dongbaek-dongsan, and 3 families and 7 species of birds in the 1100-altitude wetland. No results from field survey were available for these species. The identified birds were predominantly nocturnal, including Otus sunia (Oriental Scops Owl) and Ninox japonica (Northern Boobook), passage migrants, including Larvivora cyane (Siberian Blue Robin), L. sibilans (Rufous-tailed Robin), and winter visitors with a relatively small number of visiting individuals, such as Bombycilla garrulus (Bohemian Waxwing) and Loxia curvirostra (Red Crossbill). Fifth, the birds detected in the field survey but not through bioacoustic detection included 18 families and 48 species in Dongbaek-dongsan and 14 families and 27 species in the 1100-altitude wetland; the most representative families were Ardeidae, Accipitridae, and Muscicapidae. This study is significant as it provides essential data supporting the possibility of an effective survey combining bioacoustic detection with field studies, given the increasing use of bioacoustic devices in ornithological studies in South Korea.

Effectiveness Analysis Tool for Underwater Acoustics Detection in Quasi-static Underwater Acoustics Channel based on Underwater Environmental Information DB (수중 환경 정보 DB 기반 준-정적 수중음향 채널 수중음향 탐지 효과도 분석 모의 도구 구현)

  • Kim, Jang Eun;Han, Dong Seog
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.10
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    • pp.148-158
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    • 2015
  • It is difficult to test a detection system in underwater acoustics channel environments. The system can be evaluated by using simulation analysis tool. In this paper, a simulation tool is proposed to analyze the effectiveness of underwater acoustics detection based on database for real environments. First, the underwater environment is built based on HYCOM underwater environment database. Then, a multipath characteristic is considered through calculating underwater acoustics propagation path/pressure based on the ray theory. Also, hydrophone thermal noise and underwater ambient noise are considered to reflect underwater noise characteristics.