• Journal of Power System Engineering
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• v.11 no.4
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• pp.72-77
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• 2007

It is known that elimination of ship engine room noise is impossible thing, so the working environment in the engine room is getting worse because ships are recently built with huge engines to take higher sailing power. In the yacht and cruise yacht, the engine room noise is more serious because they have bigger engines relative to their hull sizes. The noise generated from the main engine makes the employee to hearing loss and the transmitted noise make the uncomfortable conditions in the cabins of ship. The noise generated by ship engine must be attenuate for the employee and passenger. In yacht and cruise yacht, the noise levels in cabines are the most important criterions to the value of commodities. In this study, the noise absorbtion barrier which have resonators is experimentally studied by the 1/3 octave band noise elimination rates(%).

• Journal of IKEEE
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• v.13 no.2
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• pp.248-252
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• 2009

In this paper, analysis of a noise factor and an effective power strategy for the OLED dc-dc converter are described. One of the main reasons that one may not design the OLED power for dc-dc converter is that OLED's panel noise is composed of FFN(Frame Frequency Noise) and LFN(Line Frequency Noise). Into the bargain, FFN is caused by both the dc-dc (circuit) and driving circuit. It is hard to get rid of FFN, baeause FFN has very little results value for our ears. LFN is adjusted by analog compensation value. Actually, that is more important problem than FFN. It is known that voltage divider for OLED's mode variation is not good for compact power design. In the end, a circuit design for understanding OLED's noise and a novel muti-channel dc-dc converter were presented.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.42-45
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• 2017

It is known that power line communication systems have more noise than general wired communication systems due to the high voltage that flows in power line cables, and the noise causes a serious performance degradation. In order to mitigate performance degradation due to such noise, this paper proposes an artificial intelligence algorithm based on polynomial regression, which detects signals in the impulse noise environment in the power line communication system. The polynomial regression method is used to predict the original transmitted signal from the impulse noise signal. Simulation results show that the signal detection performance in the impulse noise environment of the power line communication is improved through the artificial intelligence algorithm proposed in this paper.

• Journal of KSNVE
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• v.7 no.2
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• pp.281-291
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• 1997

This study analyzes the problem of environmental impact assessment for building steam power plants, particularly that of noise assessment for building the Dangjin steam power plant. It concludes that the laws and regulations for noise assessment and its methodology should be amended, and offers certain proposals.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1241-1246
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• 2001

In this study, we measured and analyzed the interior noise, the rolling noise and the engine noise at Honam line(Seodaejeon- Jangseong) for passenger and power cars. The noise level is below 69㏈A for Seamaeul PMC(Powered Motor Car) coachs, below 65㏈A for Seamaeul and Mukungwha coachs, over 80㏈A for the driver's room of PMC and DEL (Diesel-Electric Locomotive). We also proposed the criteria of interior noise in free field conditions, below 67㏈A for passenger cars, below 86㏈A for power cars.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.452-459
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• 1997

For computer aided design and construction of low noisy power plants, indoor and outdoor noise prediction program has been developed. The program utilizes the predefined data of noise sources and building materials and has the faculty to estimate the source level using the empirical formula in case of the measured data not being available. In the noise prediction, the mutual noise propagation between indoor and outdoor sites are considered. The outdoor noise source in the calculation of geometric divergence effects is modelled as the omni-directional finite line or planar source according to the source geometry and the receiving points. Outdoor noise prediction is carried out to consider the diffraction effect due to plant structures as well as the attenuation effect due to atmospheric absorption and soft ground. The results of indoor and outdoor noise prediction for a recently constructed diesel engine power plant show good agreement with the measured.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.554-558
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• 2004

In this paper, we introduce noise prediction program of HVAC system to assist low-noisy design of ship's cabin. The developed program calculates sound power levels at HVAC components considering primary and secondary noise generated by fan and duct element, duct element noise attenuation, and duct break-in noise based on the authentic empirical method suggested by NEBB and acoustic power balancing method. Sound pressure level at cabin with or without ceiling system is evaluated by the diffuse-field theory considering diffuser and duct break-out sound powers. Moreover, the program provides intuitive pre- and post-processors using modem GUI functions to help efficient modeling and evaluation of cabin and HVAC component noise. To validate the accuracy and convenience of the program, noise prediction for a HVAC system is demonstrated.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.199-203
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• 2019

In this paper, we propose the efficient impulsive noise mitigation scheme for power line communication (PLC) systems in smart grid applications. The proposed scheme estimates the channel impulsive noise information of receiver by applying machine learning. Then, the estimated impulsive noise is updated in data base. In the modulator, the impulsive noise which reduces the PLC performance is effectively mitigated through proposed technique. As an impulsive noise model, Middleton Class A interference model was employed. The performance is evaluated in terms of bit error rate (BER). From the simulation results, it is confirmed that the proposed scheme has better BER performance compared to the conventional model. As a result, the proposed noise mitigation improves the signal quality of PLC systems by effectively removing the channel noise. The results of the paper can be applied to PLC systems for smart grid.

• Economic and Environmental Geology
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• v.31 no.1
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• pp.53-57
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• 1998

Transient electromagnetic (TEM) method is also affected by cultural and natural electromagnetic (EM) noises, since it uses part of the broadband ($10^{-2}$ to $10^5Hz$) spectrum. Especially, predominant EM noise which affects a moving transmitter-receiver TEM system is sensor motion-induced noise. This noise is caused by the sensor motion in the earth magnetic field. The technique for reducing the sensor motion-induced EM noise presented in this paper is based on Halverson stacking. This Halverson stacking is generally used in a time-domain induced polarisation (IP) system to reject DC offset and linear drift. According to spectrum analysis of the vertical component of sensor motion-induced noise, the frequency range affected by the motion of an EM sensor is less than about 700 Hz in this study. With the decrease of the frequency, the spectral power caused by the motion of a sensor increases. For example, at the frequency of 200 Hz, the spectral power of the sensor motion-induced noise is $-90dBVrms^2$ while the spectral power of the EM noise measured with a fixed sensor on the ground is $-105dBVrms^2$, and at the frequency of 100 Hz, the spectral power of the sensor motion-induced noise is $-70dBVrms^2$ while the spectral power of the EM noise measured with a fixed sensor on the ground is $-105dBVrms^2$. With applying Halverson stacking to an artificial noise transient generated by adding a noise-free transient to sensor motion-induced noise measured without pulsing, it is shown that the filtered transient is nearly consistent with the noise-free transient within a delay time of $0.5{{\mu}sec}$. The inversion obtained from this filtered transient is in accord with the true model with an error of 5%.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.328-334
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• 2012

Power flow finite element method(PFFEM) combining power flow analysis(PFA) with finite element method is efficient for vibration analysis of a built-up structure, and power flow boundary element method(PFBEM) combining PFA with boundary element method is useful for predicting the noise level of a vibrating complex structure. In this paper, the coupled PFFE/PFBE method is used to investigate the vibration and radiated noise of the unmanned underwater vehicle(UUV) in water. PFFEM is employed to analyze the vibrational responses of the UUV, and PFBEM is applied to analyze the underwater radiation noise. The vibrational energy of the structure is treated as an acoustic intensity boundary condition of PFBEM to calculate underwater radiation noise. Numerical simulations are presented for the UUV in water, and reliable results have been obtained.