• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.368-372
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• 2008

Habitability is one of the most important points when a passenger ship is cruising. In particular, anti-vibration design should be considered preferentially to offer passenger a comfort cabin and leisure space. But, a passenger ship is different from a general commercial ship in the view point of the structural arrangement. It is restricted within narrow limits to reinforce wide panels and local structures of a passenger ship because of its interior design. Moreover, the allowable vibratory limits for a passenger ship are much lower than those of a commercial ship. In this study are introduced the procedure of the vibration analysis, the structural improvement method for prevention of vibration and the results of vibration measurement during exciter test and sea trials.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.753-756
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• 2011

Recently the construction of railway sections passing the central area of cities and stations under railway lines are increasing, and then it is urgently required to take the countermeasures against the railway vibration and the second-phase noise radiated from it. The most efficient countermeasure, out of technologies developed up to now, is the floating slab track which is the track system isolated from the sub-structure by springs. In other countries, the source technologies for anti-vibration design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the system design technology and technologies for key components are not yet developed, the foreign system are being introduced without any adjustment, and the key component, vibration isolator, depends on imports. In this study, analysis on floating slab system installed rubber mat and stopper is carried for the examination on the safety of floating slab system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.875-879
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• 2006

Noise reduction has become a major issue of the duct air-conditioners. This paper describes the reduction of noise and vibration of rotational slim duct system. The design of slim duct system is the most important point of noise reduction in terms of the motor of 2f line noise, resonance noise between forced frequency and natural frequency of Sirocco fan, unbalance noise of motor axis and the noise induced refrigerant. The noise of duct system is mainly measured from diffuser and bottom of duct. The optimal design was implemented after measuring the effect of noise and vibration in each part which is composed of duct system. In this paper, experimental results show that the main elements in air-conditioner duct design. These elements are anti-vibration rubber of motor, axis length of motor, rubber coupler, materials of sirocco fan and control method of motor which are the most vital factors in reducing noise.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.82-88
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• 1999

In order to execute the major role as the high density large capacity data storage device, which is one of the major characteristics of DVD(Digital Versatile Disk), there must be a method to effectively absorb the external impact or internal vibration. The DVD which has been developed until now tries to control two different types of vibrations, using only one absorber. But this goes against the independence Axiom of Axiomatic Approach which makes the design to be coupled. And in fat most of the malfunctions occurring during DVD data input/output is due to impact or vibration. Therefore in this paper, the vibration absorption system and operation reliability of DVD will be evaluated with the Axiomatic Approach and plans and feasibility to design an improved vibration absorption system will be provided also based on the Axiomatic Approach.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.690-695
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• 2006

This paper described the Performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.725-731
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• 2003

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-.oiling system (MD-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. We adopt anti-windup technique to improve the control performance and demonstrate its efficiency by simulation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.8 s.113
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• pp.857-863
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• 2006

This paper described the performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.421-428
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• 2005

This paper described operation and vibration characteristics of a 'tail-fan' anti-torque performance test system. KARI (Korea Aerospace Research Institute) developed a 'tail-fan' anti-torque system of a helicopter and a performance test-rig to test the performance of the tail-fan. The performance test-rig consists of driving, supporting and rotating parts. In the process of the performance test, firstly, operation test of the test-rig were carried out to verify design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for the performance test, vibration test were carried out using accelerometers on tail gear box. The performance test conditions of the tail-fan to avoid a resonance were found from the fan-plot and vibration test results. The tail-fan performance tests were well done safely.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.268-272
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• 2010

Recently the construction of railway sections passing the central area of cities and stations under railway lines are increasing, and then it is urgently required to take the countermeasures against the railway vibration and the second-phase noise radiated from it. The most efficient countermeasure, out of technologies developed up to now, is the floating slab track which is the track system isolated from the sub-structure by springs. In other countries, the source technologies for anti-vibration design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the system design technology and technologies for key components are not yet developed, the foreign system are being introduced without any adjustment, and the key component, vibration isolator, depends on imports. In this study, floating slab was divided into three spans, $k_{dynamic}$ use by examining reactions and member forces was to ensure safety.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.195-196
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• 2005

We report the new design of a miniature electromagnetic actuator for probe-based data storage with anti-vibration mechanism. The actuator consists of a media substrate, silicon frame, 2 pairs of magnets, a spacer, and a printed circuit board (PCB). The total area of the device is $11.2{\times}11.2 mm^2$ while the data recording area is $7.4{\times}7.4 mm^2$. A net momentum fee structure was included for high vibration resistance. The simulation shows that the lateral vibration can be reduced to below 100 nm for 1 G acceleration if the counter mass is adjusted with $1\%$ difference. The peak power for ${\pm}50 {\mu}m$ displacement is below 50 mW for a actuator with a resonance at 200 Hz.