• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.292-295
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• 2006

Dimension and capacity of the zero tail type mini excavator are small as compared with medium or large excavators. Therefore, problems of the noise and the heat are major issues in design due to layout of each component such as the engine and the hydraulic module. It is necessary to reduce the noise and the vibration of construction machine, due to be enforced regulation for high noise construction machinery in the world. The objective of this study is to provide basic data which is apply to predict noise effect in detail design stage by estimating noise of cabin for zero tail type mini excavator.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.79-86
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• 1997

The need for an active exhaust moise controller has been growing as an reinforcement of exhaust noise regulation, high power output and improvement of average fuel economy. In this study, for development of this active exhaust noise controller, the implementation of a composition of realtime control algorithm for active exhaust noise control and the construction of simulator for realtime control algorithm for active exhaust noise control has been investigated. Also, in order to implement active exhaust noise control with this simulator, the feasibility model for control of vehicle exhaust noise control is suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.187-192
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• 2006

Helicopter noise has been considered as one of major design factors like a performance and safety since the public acceptance, comfortability and stealth aspects were important for customers. According to the airworthiness regulation, the noise levels in throe different flight conditions shall comply with the specific limits. Main and tail rotors noise is most dominant in far field due to the low and mid range frequency characteristics. It is an air-born noise so That the accurate aerodynamic data is necessary for the accurate noise prediction. In KARI, low noise main and tail rotors as well as analysis codes have been developed since 2000. The approach for low noise main rotor is a kind of tip modifications, so called twin vortices tip to reduce the BVI noise. Analysis results show the 9.3dB reduction in terms of pseudo EPNL. The uneven spacing concept is applied for low noise tail rotor. Three or four decibel noise reduction is achieved by new optimized uneven spacing. Rotor noise and aerodynamic prediction codes have been improved also.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.550-553
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• 2004

Recently, the demand for the Floating, Production, Storage, and Offloading facility (FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. The 36,8000 DWT class FPSO was built in Hyundai Heavy Industries and will be installed in Offshore Angola. She dose not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise sources are contributing to the cabin noise of the accommodation are classified into three classes such as the machinery in the engine room and the deckhouse, HVAC system, and the topside equipments. In general, the noise regulation for the offshore structure is severer than that of the cargo ship and acceptable noise limit of cabin is specified as 45 dB(A). This paper describes the procedure of noise analysis, the countermeasures of noise control, and the measurement results of the quay trial. In order to minimize the noise levels, careful attention have to be paid by the special committee of experts from the initial design stage to the delivery. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various experiment results. Finally, this ship was successfully delivered with excellent noise properties. The technology to minimize the noise levels for FPSO has been established throughout the construction of this ship.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.159-163
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• 2004

The KNR(Korean National Railroad) has a speed limit regulation(130km/h) for the train passing the turnout to guarantee a safety. Since that speed is set as below the maximum commercial speed(140km/h), it has been regarded as a major factor to obstacle the total efficiency. The crossing rail part of the turnout system is formed into a antisymmetric, furthermore, there are several discontinuous part. Thus, measuring the strain signals of this part is impossible actually and it must be in the most difficult work related the turnout research. In this research, the program that can anticipate the signals at the various conditions with considering its own shape was developed and the preciousness of its results had been examined by comparing analyzed and measured ones at the other parts. The simulation was performed with varying the factors such as train speed and contact depth. As a results, it was proved that the regulation was not useless and very important guide at least up to now.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.683-686
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• 2007

The characteristics of radiated noise from the hydraulic breaker were measured under the revised regulation of Ministry of environment. The directivity of radiated noise was also measured at a distance of 7.5 m and a height of 1.5 m from the operating hydraulic breaker.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.524-525
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• 2009

Heavy-weight impact noise(HN) is the most irritating noise in Korean apartment houses. It has been proclaimed standard floor system of 210mm thick slab with isolation material in the wall type structure. But this regulation is applied only new construction field and is not considered remodeling field. In general, the LN can be reduced by using isolation material but HN is known as relating with stiffness, strength & boundary condition of slab. Therefore it is difficulty in improving the HN on remodeling field. In this study, We conducted the reinforcement of concrete slab using C.F.S.(carbon fiber sheet), steel plate and steel beam after on-dol with isolation material on the remodeling field. As the test results, It appeared using C.F.S was no improved but using steel plate & steel beam were a little improved on HN.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.876-878
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• 2008

The standards of acceptable limit and compensation is one of the most important things in environmental noise and vibration disputes resolution. In this paper, review on the present acceptable limit level and compensation standard in National Environmental Dispute Resolution Commission is introduced. Discordance of standards between in the regulation law and in the dispute resolution commission and it's improvement are discussed. Abnormal reasoning for compensation standards is pointed out from a author's private view.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.643-648
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• 1997

Concern for noise problems of a commercial aircraft in community and cabin is increasing due to the more restrictive regulation and customer requirements. This paper introduces to the work packages of the aircraft noise engineer for the development of a commercial aircraft. First of all, the noise engineer establish the design requirement and objectives(DR&O). Then the design and analysis are performed to satisfy with the DR&O during the conceptual and preliminary design phase. And the test and evaluation(T&E) are carried out to verify the analysis results and to acquire the type certification.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.447-451
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• 2006

Automobiles become indispensable to our lives of modern days, however, their abrupt increase causes environmental problems. Relevant regulations domestically and internationally, therefore, have been discussed and reinforced for tackling those problems. The current test methods such as ISO 362 which have been adopted in many countries need to be reviewed to be effective, considering the changes in automobile techniques and road conditions. This research is aimed at providing counter-plans for the expected new measures by analyzing both the current and new test methods.