• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.783-788
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• 2004

Recently, Statistical Energy Analysis(SEA) is being increasingly applied to describe vibro-acoustic behavior of complex structures, such as air plane, automobile, ship, building. In this paper, we discuss the application of SEA to predict the interior noise for KTX train. To validate the SEA model of KTX train, calculated the interior noise for motorized car is compared to measured one. Finally, the reduction measures of interior noise for KTX are also discussed.

• 한국군사과학기술학회지
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• 제10권1호
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• pp.14-21
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• 2007

This paper proposes SDINS(strapdown inertial navigation system) transfer alignment method for vertical launcher using an adaptive filter in the ship. First, the velocity and attitude matching transfer alignment method is designed to align SDINS for vertical launcher. Second, the adaptive filter is employed to estimate measurement noise variance in real time using the residual of measurements. Because it is difficult to decide measurement noise variance when noise properties of the ship SDINS are changed. To verify its performance, it is compared with the EKF(Extended Kalman filter) using uncorrect measurement variance. The monte carlo simulation results show that proposed method is more effective in estimating attitude angle than EKF.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.655-660
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• 2000

Machines on board a ship are mounted on decks and transmit its structure-borne sound to the deck through resilient mounts. To predict the ship noise generated by the structure-borne sound of the machine, It is necessary to estimate the vibration level of the base structure. In this paper, a simple dynamic model is considered for vibration isolation systems consisting of a source, an isolator, and a base structure. The high frequency mobilities of the simple base structure are reviewed and wave effects in the mount are discussed in relation to isolation performance.

• 한국해양공학회지
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• 제26권3호
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• pp.13-19
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• 2012

Recently, as the importance of the interior noise in a ship cabin has risen, ship builders have becomeconcerned about the use of noise reduction panels to reduce cabin noise. The results of previous researches have been based on analytical and experimental methods using simple sandwich panels. However, panel structures are becoming more complex to improve the transmission loss. Thus, researches that analyze the transmission loss of a panel are reaching the limit of study. This paper reports on research that was performed to determine the sound transmission characteristics of multi-complex panels applicable to high value-added vessels. It presents comparisons between analytical methods and experimental results by using a mini-reverberant chamber with components of sound attenuation panels, including the core and surface materials. The sound transmission loss of multi-complex panels are also analyzed in terms of the influences of the inside perforate plates and air gap thickness on the attenuation. Finally, the multi-complex panel with the highest noise attenuation is proposed based on the analysis results and experimental results in mini-reverberant chamber, which wereverified using a real-size reverberant chamber.

• 대한조선학회논문집
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• 제43권6호
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• pp.693-699
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• 2006

This paper proposes a design optimization technique for ship RCS signature reductions using Taguchi method. The proposed technique comprises of i)evaluating initial RCS signatures, ii)defining critical areas which should be modified as design parameters, and threat factors which can't be controlled artificially as noise parameters, and finally iv)finding optimum parameters via analyzing signal to noise ratios for designated characteristics. We applied the technique to a model ship and found that it is suitable for radar stealth designs. In addition, the proposed technique is applicable to submarine designs against sonar threats.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.329-330
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• 2008

The 181,000 DWT Bulk Carrier has a different deck house type, which is not typical for previous bulk carriers, to meet the new international rules for bulk carriers. This new deck house has much smaller transverse breadth than the hull's transverse breath, resulting in large levels of the transverse response of the deck house. In addition, the longitudinal response of the funnel showed rather a large magnitude of vibration, which are excited by the ship's main excitations such as the main engine H-moment and the propeller surface forte when the ship operates at the NCR and the MCR speeds In the ballast condition. To solve these issues, the global forced vibration analysis has been performed for the ship and the ship structure has been modified to reduce the vibration level by increasing the girder depth and adjusting the engine room tank arrangement.

• 한국군사과학기술학회지
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• 제19권4호
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• pp.500-507
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• 2016

In order to increase the survivability of combatant ship, measuring and analyzing the infrared radiation is important. Consequently, providing analysis report is also important for the progress of the new combatant ship design. This paper proposes a design and software implementation of filtering for the noise reduction of mid-wave IR camera image. We reduced the total test cost by using the suggested software filtering technique instead of hardware replacement or re-calibration. In addition, we enhanced the accuracy of analysis results by adjusting the parameters of software filtering according to the results of filtered image.

• 한국소음진동공학회논문집
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• 제21권7호
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• pp.650-656
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• 2011

The noise inside a naval vessel is very important in considering the need for hearing protection, improving the working environment and maintaining good communications for crews living on board a naval vessel. The indoor noise of a ship usually is specified by the A-weighted sound pressure level, but other evaluating parameters are required to reflect human senses more effectively. This paper uses additional noise indices related to room acoustics, such as NR(noise rating), NC(noise criterion), RC(room criterion), PSIL(preferred speech interference level) and loudness level to evaluate the noise inside cabins on a naval vessel. Using these psychological noise indices, allowable limit of noise level in cabins is suggested through psycho-acoustic evaluation for the noise in cabins.

• 대한조선학회논문집
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• 제31권1호
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• pp.133-141
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• 1994

본 논문은 통계적에너지 해석법(SEA)을 이용하여 선박소음해석 프로그램을 개발하는 과정중에 얻어진 연구결과를 소개하였다. 주요 내용은 SEA를 이용한 실선 소음해석 프로그램 NASS의 해석 모듈 개발과 검증, 그리고 선체구조 및 격실에 대한 모델링 기법이 제시되었다. 또한 NASS를 이용하여 실선에 대한 공기음 및 고체음 예측을 수행하였으며 이를 실선 계측값과 비교검토하였다. 비교 결과로부터 모델링 기법 및 방사효율 산정의 문제점을 발견할 수 있었으나, 상부갑판에서는 오차가 5 dB 이내였으며 특히 종래의 경험적인 방법으로서는 불가능했던 밴드별 경향의 일치등 긍정적 결과를 얻을 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.391-395
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• 1997

The transmission of sound and vibration through structures is of interest in many noise control problems, including architectural acoustics, sound transmission through air craft, spacecraft and ship, and the transmission of noise through machinery and engine enclosures. Statistical Energy Analysis provides a simple and accurate method of approaching these problems. In this paper, comparing the measured coupling loss factor of plate-beam with measured coupling loss factor of mass on the junction will be inspected.