• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.716-718
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• 2011

첨단 과학기술의 발달에 따라 미래 해전의 양상은 비대칭적인 전략과 수단이 보편화되는 양상으로 전개될 것으로 전망되며, 비대칭전력의 핵심인 잠수함의 중요성이 대두 될 것으로 판단된다. 따라서 본 논문에서는 중요성이 대두되는 잠수함 측면에서 잠수함을 탐지하는 대잠전 탐지체계를 분석한 결과 소나체계인 음향탐지체계와 전자파, 자기, 광학장비 등으로 탐지하는 비음향탐지체계로 구분되며 각각의 탐지체계로부터 탐지를 거부하고 생존력을 증대시키기 위해 필요한 잠수함의 스텔스 발전 방향을 제시하였다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.11a
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• pp.324-328
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• 2007

본 논문은 감시정찰 센서네트워크에서 센서노드의 주요 기능인 표적의 탐지 및 식별을 위한 알고리즘을 제안한다. 감시정찰 센서네트워크에서 각 센서노드는 노드의 크기 및 센서, 프로세서, 네트워크, 전원 등의 자원의 제약이 있기 때문에 침입하는 적의 탐지 및 종류 식별을 위해서는 효율적인 알고리즘의 선정과 최적화가 요구된다. 본 논문에서는 음향, 진동, PIR, 자기 센서 등을 이용하여 사람, 차량 및 궤도 차량의 침입을 탐지하기 위한 적응 임계값 알고리즘과 그 종류를 식별하기 위한 최대우도추정 기법, k-최근접 이웃 추정 기법에 기반한 표적의 탐지 및 식별 알고리즘을 제안한다. 실험결과 음향 및 진동 센서에 의한 차량의 탐지, PIR 센서에 의한 사람의 탐지가 가능함을 확인할 수 있었으며 주파수 특징점을 이용하여 차량과 궤도차량의 종류식별이 가능함을 확인할 수 있었다.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1961-1963
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• 2003

수중에는 대기중에서와는 달리 음향, 압력, 전자기장 등이 주 탐지원이 된다. 이중 선체에서 발생되는 전자기장은 강자성체로부터 발생되는 정 자기장 이외에 선체 자체의 부식과 부식 방지 장치에서 발생되는 정전 자기장 및 ELFE대역의 교류 전 자기장으로 나눌수가 있다. 이처럼 수중에서 탐지 가능한 비음향 전자기 신호원이 교류 전자기장 등으로 다양화됨에 따라 선체 건조시 이러한 신호 발생원들의 종합적인 관리 및 감소 대책이 요구된다. 따라서, 본 논문에서는 선체에서 발생되는 전자기장 신호원의 종류와 발생원인을 기술하고, 이러한 신호원들을 감소시키기 위한 대책을 소개하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1253-1258
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• 2013

This Paper deals with detection and defense methods for underwater weapons because there are so many dangers of underwater weapons not only in the war period but also in the peace time. Underwater mines are the representative strategic arms. The sensors and target detection methods, threat elimination method of mines included in this paper. Among the various sensors of mine, we use the magnetometor for target detection method in the simulation and execute the analysis of magnetic field of detected target ships. It will be also provided that effectiveness of target detection, sweeping method of mine, tactics of mine planning and mine sweeping and so on.

• Journal of Welding and Joining
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• v.12 no.4
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• pp.1-10
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• 1994

이 글에서는 비파괴검사개론에 관하여 알아보았다. 1. 비파괴검사의 의의 1.1 비파괴검사의 역사 1.2 비파괴검사의 원리 1.3 비파괴검사의 목적과 역할 1.3.1 품질관리 1.3.2 생산원가의 절감 1.3.3 품질의 평가 1.3.4 점검 1.4 비파괴검사자의 역할 2. 비파괴검사자의 방법 2.1 방사선투과시험 2.1.1 직접촬영법 2.1.2 투시법 2.1.3 전자사진법 2.1.4 계기법 2.2 초음파탐상시험 2.2.1 음향검사와 초음파탐상 2.2.2 초음파의 성질과 종류 2.2.3 접촉매질 2.2.4 초음파 탐상 방법 2.2.5 초음파 탐촉자 2.3 자기탐상시험 2.3.1 자기탐상 원리 2.3.2 자기탐상 방법 1) 자장측정 탐상법 2) 자기기록 탐상법 3) 탐사 코일법 4) 자분탐상시험 2.3.3 자분탐상시험 2.4 침투탐상시험 2.4.1 침투탐상시험의 원리 2.4.2 침투탐상시험법의 기본 1) 침투탐상시험의 종류 2) 현상체의 종류 2.4.3 침투탐상시험의 장단점 2.5 전자유도시험 (와전류탐상법) 2.5.1 와전류의 발생과 탐지 2.5.2 와전류의 탐지 2.5.3 와전류 탐촉자 2.5.4 와전류 탐상시험의 적용과 장단점.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.468-479
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• 2022

To detect targets with active sonar system in the underwater environments, the targets are localized by receiving the echoes of the transmitted sounds reflected from the targets. In this case, reverberation from the scatterers is also generated, which prevents detection of the target echo. To detect the target effectively, reverberation suppression techniques such as pre-whitening based on autoregressive model and principal component inversion have been studied, and recently a Non-negative Matrix Factorization (NMF)-based technique has been also devised. The NMF-based reverberation suppression technique shows improved performance compared to the conventional methods, but the geometry of the transducer and receiver and attenuation by distance have not been considered. In this paper, the performance is improved through preprocessing such as the directionality of the receiver, Doppler related thereto, and attenuation for distance, in the case of using a continuous wave with a bistatic sonar. In order to evaluate the performance of the proposed system, simulation with a reverberation model was performed. The results show that the detection probability performance improved by 10 % to 40 % at a low false alarm probability of 1 % relative to the conventional non-negative matrix factorization.

• The Journal of the Acoustical Society of Korea
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• v.36 no.2
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• pp.108-114
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• 2017

We have experimentally analyzed the self-radiation impedance of an ultrasonic transducer with a square radiation surface that is used as a vibrator in underwater ultrasonic detection systems. The radiation reactance and the radiation resistance were measured in the range from 1 to 3 of ka that is the product of a wave number and a length of the edge of the square vibrator. By comparing the measured results with those of theoretical calculation of the radiation impedance using a series, we confirmed the validity of the experimental method and experimentally confirmed the variation trend in the radiation impedance of the square radiation surface.

• Geophysics and Geophysical Exploration
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• v.11 no.3
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• pp.167-176
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• 2008

Lau basin of the south Pacific, as an active back arc basin, is promising area bearing seafloor massive hydrothermal deposit that is located in a subduction zone between the Pacific ocean plate and Indo-Australian continental plate. We performed multi-beam bathymetry survey in the Lau basin using EM120, to find out high hydrothermal activity Bone. Fonualei Rift and Spreading Center (FRSC) and Mangatolou Triple Junction (MTJ) area were selected for precise site survey through seafloor morphology investigation. The result of surface and deep-tow magnetometer survey showed that Central Anomaly Magnetization High (CAMH) recorded which is associated with active ridge in FRSC-2 and revealed very low magnetic anomalies that can be connected to past or present high hydrothermal activity in MTJ-1 seamount area. Moreover, the physical and chemical tracers of hydrothermal vent flume, i.e., transmission, hydrogen ion concentration (pH), adenosine triphosphate (ATP), methane (CH4) by use of CTD system, showed significant anomalies in those areas. From positive vent flume results, we could conclude that these areas were or are experiencing very active volcanic activities. The acquired chimney and hydrothermal altered bed rock samples gave us confidence of the existence of massive hydrothermal deposit. Even though not to use visual exploration equipment such as ROV, DTSSS, etc., traditional marine geophysical investigation approach might be a truly cost-effective tool for exploring seafloor hydrothermal massive deposit.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.29-38
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• 2024

The Matched Field Processing (MFP) is an estimation method for a source range and depth based on the prediction of sound propagation. However, as the frequency increases, the prediction inaccuracy of sound propagation increases, making it difficult to estimate the source position. Recently proposed, the Frequency-Difference Matched Field Processing (FD-MFP) is known to be robust even if there is a mismatch by applying a frequency-difference autoproduct extracted from the auto-correlation of a high frequency signal. In this paper, in order to evaluate the performance of the FD-MFP using a horizontal line array, simulations were conducted in the environment of the East Sea of Korea. In the area of Bottom Bounce (BB) and Convergence Zone (CZ) where detection of a sound source is possible at a long range, and the results of localization were analyzed. According to the the FD-MFP simulations of horizontal line array, the accuracy of localization is similar or degraded compared to the conventional MFP due to diffracted field and mismatch of sound speed. There was no clear result from the simulations conforming that the FD-MFP was more robust to mismatch than the conventional MFP.