• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.924-928
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• 2002

Response of the rail surface is an important factor for the train safety and comfortable travel, and evaluation of vibration at the area along a rail is an important factor for the vibration. The dominant method to reduce the vibration that reach the ground is installing vibration absorber between rall and the under structure. In this paper, we evaluated the vibration reducing effect of using vibration control sleeper pads to slave and earth at certain distance from the sleepers.

• Journal of KSNVE
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• v.3 no.4
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• pp.325-330
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• 1993

The longitudinal vibration of the tape in the tape transport system influences the performance of the nagnetic tape-recording system. Generally it is controlled by a passive method with impedance roller which is easy to implement and cost-effective. Therefore the effect of the impedance roller in reducing the tape vibration was analyzed in this paper. The practical tape transport system was modelled mathematically as a mass-spring system. Both simulation and experimental study were carried out in order to show the vibration reduction effect of the impedance roller.

• Journal of Korean Association for Spatial Structures
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• v.7 no.4
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• pp.97-104
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• 2007

This paper is concerned with the vibration characteristics of medium-rise building, which severely vibrated by vehicles. The field vibration measurement was employed for finding the vibration source and vibration reducing method. Time domain data from measurements were also utilized for vibration characteristics, such as effect of buses and subways-induced vibration on the floor vibration of the building. effectiveness of the vibration reducing method was also demonstrated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.496-499
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• 2008

The noise reducing devices installed on the noise barrier have been developed in many shapes and ways to reduce noise around road traffic areas. In this study, test and estimation method for the noise reducing device witch installed on the top of a noise barrier was suggested. For this, the authors have considered sound power flow around the device and sound pressure levels for the far field area. To estimate the area effect behind the barrier, area average of noise pressure level difference divided by two area, upper and bellow the sight-line. Comparing the attenuation difference of these areas, the tendency of noise reduction effect was studied according to type of noise reducing devices. Compared with noise shielding efficiency of the devices that using equivalent height of a simple barrier calculated by the SoundPlan, the commercial environment noise simulation software.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.2
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• pp.119-126
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• 2022

This paper presents a method to reduce the vibration-induced noise effect of an inertial measurement device mounted on a self-driving vehicle. The inertial sensor used in the GNSS/INS integrated navigation system of a self-driving vehicle is fixed directly on the chassis of vehicle body so that its navigation output is affected by the vibration of the vehicle's engine, resulting in the degradation of the navigational performance. Therefore, these effects must be considered when mounting the inertial sensor. In order to solve this problem, this paper proposes to use an in-house manufactured vibration suppression device and analyzes its impact on reducing the vibration effect. Experimental test results in a static scenario show that the vibration-induced noise effect is more clearly observed in the lateral direction of the vehicle, but can be effectively suppressed by using the proposed vibration suppression device compared to the case without it. In addition, the dynamic positioning test scenario shows the position, speed, and posture errors are reduced to 74%, 67%, and 14% levels, respectively.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1395-1403
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• 2002

The characteristics of gear meshing vibration undesgo change as the vibration is transmitted from the gear to the housing. Therefore, vibration transmission characteristics of helical gear systems must be understood before the effective methods of reducing gear noise can be found. In this work, using a helical gear with different lead errors, the gear vibration in the rotational direction and the bearing vibration are measured. The frequency characteristics of gear and bearing vibration are investigated and a comparson is also provided.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.5
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• pp.584-593
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• 2016

In this study, an improvement design method for reducing the vibration of fenders equipped in a tractor is proposed through the establishment of a finite element model and the topology optimization. As the original shapes of the parts cannot be altered, an improved design model was derived in which a stiffener was attached to the border of parts. Thus, the first resonance frequency was increased by approximately 16 Hz, which was confirmed to be the frequency interval for avoiding the idle and operating frequency of the engine. Finally the improved design model was applied to confirm the effect of vibration reduction. Therefore, it can be concluded that the improved design model of the tractor fender is effective at reducing vibrations of the tractor fender.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.6
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• pp.357-365
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• 2020

Background: To evaluate the effectiveness of vibration as a counter-stimulatory measure in reducing subjective pain due to local anesthesia administration in children. Methods: Electronic databases (PubMed, Ovid SP, Cochrane Central Register of Controlled Trials) were searched until April 2020. Studies were screened by titles and abstracts, followed by full text evaluation of the included studies. Results: A total of seven studies involving 376 children aged 5-17 years were included in the systematic review and meta-analysis. The meta-analysis compared vibration as a counter-stimulatory measure with no vibration as a comparator. The primary outcome evaluated was pain perception or subjective pain reported by the child. The secondary outcome evaluated was objective pain evaluated in each study. The pooled mean difference favored vibration to be effective for the first outcome. Conclusion: Within the limits of this systematic review, low quality evidence suggests that vibration as a counter-stimulatory measure is effective in reducing the subjective pain reported by children during local anesthesia administration.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.305-309
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• 2006

In this paper vibration reduction characteristics of floating floors used in railway vehicles are studied. Vibration reduction characteristics are compared through a series of tests for elastically-coupled floor and rigidly-coupled floor. It was found that elastically-coupled floor has larger vibration reduction amount than rigidly-coupled floor. Around the fundamental natural frequency, however, elastic floor has poor vibration reduction effect than rigid floor. Measures to reduce structure-borne noise are also discussed based on the test results. Structure-borne noise for running railway vehicles cannot be reduced by an effort to deviate resonance between natural frequency of floors and major exciting forces. Instead, reducing vibration level of top floor and using covers which have low sound radiation coefficient will be effective for reducing structure-borne noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.368-372
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• 2002

Since rolling (Radial AC Tilt) motion in Optical Pickup Actuator causes RF signal degradation, many researches have been done to find out how to reduce rolling degree. This paper aims to introduce two methods of reducing rolling degree with their theoretical concepts and experimental results. First method rearranges magnetic circuit and the other one adjusts the proportion of the distances among mass center, actuating center and supporting center.