• Title/Summary/Keyword: Source depth

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Source depth discrimination based on channel impulse response (채널 임펄스 응답을 이용한 음원 깊이 구분)

  • Cho, Seong-il;Kim, Donghyun;Kim, J.S.
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.1
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    • pp.120-127
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    • 2019
  • Passive source depth discrimination has been studied for decades since the source depth can be used for discriminating whether the target is near the surface or submerged. In this thesis, an algorithm for source depth discrimination is proposed based on CIR (Channel Impulse Response) from target-radiated noise (or signal). In order to extract CIR without a known source signal, Ray-based blind deconvolution is used. Subsequently, intersections of CIR pattern, which is characterized by ray arrival time difference, is utilized for discriminating source depth. The proposed algorithm is demonstrated through numerical simulation in ocean waveguide, and verified via the experimental data.

Method for eliminating source depth ambiguity using channel impulse response patterns (채널 임펄스 응답 패턴을 이용한 음원 깊이 추정 모호성 제거 기법)

  • Cho, Seongil
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.2
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    • pp.210-217
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    • 2022
  • Passive source depth estimation has been studied for decades since the source depth can be used for target classification, target tracking, etc. The purpose of this paper is to solve the problem of ambiguity in the previous paper [S.-il. Cho et al. (in Korean), J. Acoust. Soc. Kr. 38, 120-127 (2019)] that source depth is estimated in two points. The patterns of phase shift of Channel Impulse Response(CIR) reflected in ocean surface and bottom is used for removing ambiguity of the source depth estimation, and after removing ambiguity, source depth is estimated at one point through the intersection of CIR. In order to extract CIR in case of unknown source signal and continuous signal or noise, Ray-based blind deconvolution is used. The proposed algorithm is demonstrated through numerical simulation in ocean waveguide.

Detection Range Estimation Algorithm for Active SONAR System and Application to the Determination of Optimal Search Depth (능동 소나 체계에서의 표적 탐지거리 예측 알고리즘과 최적 탐지깊이 결정에의 응용)

  • 박재은;김재수
    • Journal of Ocean Engineering and Technology
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    • v.8 no.1
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    • pp.62-70
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    • 1994
  • In order to estimate the detection range of a active SONAR system, the SONAR equation is commonly used. In this paper, an algorithm to calculate detection range in active SONAR system as function of SONAR depth and target depth is presented. For given SONAR parameters and environment, the transmission loss and background level are found, signal excess is computed. Using log-normal distribution, signal excess is converted to detection probability at each range. Then, the detection range is obtained by integrating the detection probability as function of range for each depth. The proposed algorithm have been applied to the case of omni-directional source with center frequency 30Hz for summer and winter sound profiles. It is found that the optimal search depth is the source depth since the detection range increase at source depth where the signal excess is maximized.

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EFFECT OF LIGHT SOURCE AND SHADE ON DEPTH OF CURE OF COMPOSITES (중합광원과 레진 색상이 복합레진의 중합깊이에 미치는 영향)

  • Na, Joon-Sok;Jeong, Sun-Wa;Hwang, Yun-Chan;Kim, Sun-Ho;Yun, Chang;Oh, Won-Mann;Hwang, In-Nam
    • Restorative Dentistry and Endodontics
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    • v.27 no.6
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    • pp.561-568
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    • 2002
  • Purpose of this research is estimating polymerization depth of different source of light. XL 3000 for halo-gen light, Apollo 95E for plasma arc light and Easy cure for LED light source were used in this study. Different shade (B1 & A3) resin composites (Esthet-X, Dentsply, U.S.A.) were used to measure depth of cure. 1, 2, and 3 mm thick samples were light cured for three seconds, six seconds or 10 seconds with Apollo 95E and they were light cured with XL-3000 and Easy cure for 10 seconds, 20 seconds, or 40 seconds. Vicker's hardness test carried out after store samples for 24 hours in distilled water. Results were as following. 1. Curing time increases from al1 source of lights, oui$.$ing depth increased(p<0.05). 2. Depth (that except 1mm group and 2mm group which lighten to halogen source of light) deepens in all groups, Vickers hardness decreased(p<0.05). 3. Vicker's hardness of A3 shade composite was lower in all depths more than B1 shade composites in group that do polymerization for 10 seconds and 20 seconds using halogen source of light(p<0.05), but group that do polymerization lot 40 seconds did not show difference(p>0.05). 4. Groups that do polymerization using Plasma arc and LED source of light did not show Vicker's hardness difference according to color at surface and 1mm depth(p>0.05), but showed difference according to color at 2mm and 3mm depth(p<0.05). The results showed that Apollo 95E need more polymerization times than manufacturer's recommendation (3 seconds), and Easy cure need polymerization time of XL-3000 at least.

Marine Seismic Survey using a Multi-source System (다중음원을 이용한 다중채널 해양 탄성파 탐사)

  • Kim, Hyun-Do;Kim, Jin-Hoo
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.209-210
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    • 2006
  • Digital technology has been applied to marine seismic survey to develop data processing technology and multi-channel marine seismic survey. In result, high-resolution marine seismic survey ended in a success. Surveys are conducted for various purposes using various frequencies of acoustic sources. A low frequency source is used for deeper penetration and a high frequency source is used for higher resolution survey. In this study, a multi-source system was used for multi-channel marine seismic survey to acquire seismic sections of both low and high frequencies. Variations of depth of penetration and resolution would be used to achieve more accurate analysis of formations. In this study, the multi-source system consists of Bubble Pulser(400 Hz) for low frequency source and Sparker(1.5 kHz) for high frequency source.

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Heat Source Modeling of Laser Keyhole Welding: Part 1-Bead Welding (레이저 키홀 용접의 열원 모델링: Part 1-비드 용접)

  • Lee Jae-Young;Lee Won-Beom;Yoo Choong-Don
    • Journal of Welding and Joining
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    • v.23 no.1
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    • pp.48-54
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    • 2005
  • Laser keyhole welding is investigated using a three-dimensional Gaussian heat source, and the heat source parameters such as the keyhole depth, welding efficiency and power density distribution factor are determined in a systematic way. For partial penetration, the keyhole depth is same as the penetration and is predicted using the experimental data. The welding efficiency is calculated using the ray-tracing method and the power density distribution factor is determined from the bead shape. Full penetration is classified into the transition, normal and excessive modes depending on the degree of keyhole opening. Thermal analysis of the bead-on-plate welds is conducted using the Gaussian heat source, and the calculated weld geometries show reasonably good agreements with the experimental results.

A Study on the Low Depth Marking Method through Laser Source Characteristic Analysis (Laser Source 특성 분석을 통한 Low Depth Marking 공법 연구 및 고찰)

  • Jeon, Sooho;Kim, Jeho;Lee, Youngbeom;Moon, Kiill
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.2
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    • pp.65-71
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    • 2022
  • In the case of Mobile PKG Trend is in a situation where a decrease in Mold Top Margin is inevitable due to its miniaturization and high capacity product requirements. However, conventional laser marking technology has an average depth of deep, and when applied to narrow top margin products, PKG strength is expected to decrease due to overlapping processing, and reliability is reduced due to poor quality such as chip damage due to laser exposure. Therefore, we have secured the technology through research on low-depth laser marking solutions that can accommodate narrow top margin products. As a result of the evaluation of applicable technology application for PKG development products, it was verified that the marking depth decreased by 67% reduced and the PKG strength increased by 12%. Furthermore, the quality verification of Laser Damage that can occur through PKG Mechanical analysis was performed, and no Chip Damage defects were found. This ensured the stability of mass production application quality.

Trial Design of a Very Large Floating Airport (General Arrangement and Decision of Depth) (초대형 부유식 해상공항의 시설계 (일반배치와 깊이 결정))

  • 신현경;임춘규;정재희
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.45-49
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    • 2001
  • The length and the breadth or a very large floating airport are determined by airplane types and airport facilities. However, the depth affect not only the structural strength but also the functional requirement such as a possibility of taking off and landing. The optimization problem for determining the depth is to select a design so that the cost is minimized. In this paper, a general arrangement and a method to decide the depth are proposed. Strength, functional requirement, and possibility of occurrence of deck wetness and slamming are considered in order to determine the depth of structure. Hydrodynamic forces of the diffraction and radiatin problems are predicted by applying the source-dipole distribution method, and the structural responses are obtained by the finite element method.

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Two-Step Diffusion of Boron into silicon by Spin-on source (스핀온 쏘스에 의한 실리콘내의 붕소의 이단계 확산)

  • 정태원
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.17 no.5
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    • pp.22-27
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    • 1980
  • The two-step diffusion process of boron into silicon has been investigated using a new diffusion source coiled "Spin-on Source". A simple method is proposei which can estimate the junction depth after the two -step diffusion for the cases where the junction depth after the predeposition is not negligible compared with the junction depth after the two-step diffusion. The estimated junction depths are, then, compared with the experimental measurements.surements.

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Numerical Analysis of Waves from Point Source in Variable Depth Using Parabolic Wave Equation in Polar Coordinates (極座標 抛物形 波動方程式을 이용한 變數深 点源波의 數値解析)

  • 곽문수;편종근
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.11 no.1
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    • pp.68-74
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    • 1999
  • The Green function method is widely used for the analysis of waves in a harbor with a constant depth. In extending this method to a wave field over arbitrary depth, a generalized and convenient method is needed to obtain unit solutions for waves emerging from a point source. For this purpose, a parabolic wave equation is derived to approximate the mild-slope equation written in terms of polar coordinates. Usefulness of the equation obtained is examined through trial computations.

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