• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.163-167
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• 2008

This paper presents the analysis of tactile effects on different body parts according to the various vibration patterns. The experiments use a vibration pad made of 16 vibration elements in the form of $4{\times}4$ array. The vibration elements are controlled by a 8-bit microprocessor. The sound of gunshot initiates a vibration pattern on different body parts and its sensitivity is measured. The analysis of the experiments lead us to conclude that the vibration pad is the most realistic interface for shooting games and the shoulder part is the most sensitive part in the body. In addition, the most effective vibration pattern is the for the pattern which gives the sensation of spreading out from the center to the outside. This study analyzes the relationship between the human body parts and the tactile sensations by the various vibration patterns. The result of this study will be a good reference for user studies in the field of haptics based on the vibration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.144-147
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• 2005

The tire is considered as one of the Important noise sources having an influence on vehicle's performance. The Pattern noise of a tire is the transmission sound of airborne noise. On smooth asphalt road, Pattern noise is amplified with the velocity. In recent, the study on the reduction of Pattern noise is energetically processed. Pattern noise is strongly related with pitch sequence. To reduce the pattern noise, tire's designer has to randomize the sequence of pitch. The FFT is a traditional method to evaluate the level of the randomization of the pitch sequence, but gives no information on time-varying, instantaneous frequency. In the study, we found that Time-Frequency transform is a useful method to non-stationary signal such as tire noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.6 s.111
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• pp.627-633
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• 2006

The tire is considered as one of the important noise sources having an influence on vehicle's performance. The Pattern noise of a tire is the transmission sound of airborne noise. On smooth asphalt road, Pattern noise is amplified with the velocity. In recent, the study on the reduction of Pattern noise is energetically processed. Pattern noise is strongly related with pitch sequence. To reduce the pattern noise, tire's designer has to randomize the sequence of pitch. The FFT is a traditional method to evaluate the level of the randomization of the pitch sequence, but gives no information on time-varying, instantaneous frequency. In the study, we found that Time-Frequency transform is a useful method to non-stationary signal such as tire noise.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.537-543
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• 2003

Transient vibration generated by developing localized fault in gear can be used as indicators in gear fault detection. This vibration signal suffers from the background noise such as gear meshing frequency and its harmonics and broadband noise. Thus in order to extract the information about the only gear fault from the raw vibration signal measured on the gearbox this signal is processed to reduce the background noise with many kinds of signal-processing tools. However, these signal-processing tools are often very complex and time waste. Thus. in this paper. we propose a novel approach detecting the damage of gearbox and analyzing its pattern using the raw vibration signal. In order to do this, the residual signal. which consists of the sideband components of the gear meshing frequent) and its harmonics frequencies, is extracted from the raw signal by the power spectral density (PSD) to obtain the information about the fault and is used as the input data of the artificial neural network (ANN) for analysis of the pattern of gear fault. This novel approach has been very successfully applied to the damage analysis of a laboratory gearbox.

• Geotechnical Engineering
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• v.11 no.3
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• pp.55-68
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• 1995

This paper is the analysis of the relationship between RQD and decay constant, blasting vi bration constant of cube root scaling and square root scaling, through experimental blast ins test in subway construction for excavation of shaft hole by bottom blasting. The magnitude of particle velocity is largely effected by the distance from blasting source, the maximum charge per delay and the properties of ground. In order to verify the effects of ground properties on blast-induced vibration, the relation-ship between magnitude of blasting vibration and Rock Quality Disignation which stands for joint property was studied. The results of test are verified that blasting vibration constant "K" and the absolute value("n") of decay constant relatively increse as RQD increased. According to the result, it can be predict the particle velocity by the blast -induced vibration in bottom blasting pattern.om blasting pattern.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.361-364
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• 2011

In this paper, This work demonstrates a experimental evaluation for vehicle road noise NVH performance from the component-level NVH measurements of Tire. The power unit noise from tire emitted by cars has been reduced. It has been found that tire noise dominates noise produced by the power train when vehicles are driven at high constant speed. Therefore tire pattern noise is affected by pattern and vehicle and transmission loss. Tire noise mechanism is generated by several mechanisms. The sound of tire can propagate either through the air or through the structure of vehicle. Pattern noise is the result of pressure variations through the air to the interior side of vehicle. Especially, smooth asphalt, the periodicity of tread design, groove depth is important factor, which have an influence on the reduction of tire pattern noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.268-270
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• 2013

It is well known that tire pattern design factors have a large influence on overall tire performance. In this paper, the basic study on the effects of tire pattern design factors on tire labeling performance has been carried out through experimental tests. The pass-by noise is affected by tire pattern design, by a maximum of 2.7dB(A), and the number of sipes gives large effects on PBN. The rolling resistance is also influenced, mostly by the number of longitudinal grooves and secondly the number of sipes. Finally, there is a weak correlation between PBN and RR when the pattern design factors are changed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.258-263
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• 2005

The nearest variety of the industrial world requires using the high precision and resolution positioning technology to do a semi-conductor, information field , and measurement field. It is especially important for the positioning technology that makes up a proper controller, is affected by the minimal heat and vibration, and can control a structurally generated non-linear friction factor to determine the efficiency of the system. The paper is to analyze the vibration characteristic according to the speed of linear motor and grasp the dynamic characteristic through the modal test and show the verification of the experimental result and design parameters by using FEM(Finite Element Method). Also, it shows the optimum standard analyzed the acceleration patterns of the moving part that lead to the vibration source in linear motor. It presents the analyzed dynamic of linear motor in compliance with a change of the non-linear factor.

• Explosives and Blasting
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• v.8 no.2
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• pp.3-17
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• 1990

The Caustious blasting have often increased Complaints of ground Vibration and Sound when the Wire-Tunnel Constructed in Pusan. In order to prevent the influence to housing structure, it was necessary to predict blasting-Induced Vibration and Sound. The Suveyer determined the Burden and spacing of Drill holes, minimum delay charges within a allowable Vibration and Sound Level. Tunnel drilling and Ignition patterns are made as follows; No. 1 Tunel (Stable rock, hard rock) No.2 Tunnel (Instable plastic rock; wethered rock) and other Tunnels (Instable rock). The result of 1st testing blasting of No. 1 Tunnel was recorded Under allowable Vibration Level but sound was over 75 Db of allowable value. So Tunnel drilling pattern was amended with 52 Non-charg holes to reduce the blast-sound. The other pattern had no need to amend.

• Journal of KSNVE
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• v.9 no.3
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• pp.509-516
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• 1999

The ESPI (Electronic Speckle Pattern Interferometry) algorithm has been simulated to calculate vibrational modes of a thin right-angled STS304 plate. The phase transformation of the reference wave of the ESPI is carried out only one time during vibration in order to clarify ESPI speckle patterns. Two dimensional vibrational modes are calculated from one ESPI pattern before vibration onset and two ESPI patterns during vibrations but with and without the phase transformation. The ESPI harmonic results are compared with those derived from the finite element method (FEM), and they agree very well. Additionally a phase unwrapping algorithm has been newly developed to derive a displacement map from an ESPI phase map.