• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.115-116
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• 2007

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.2 s.257
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• pp.145-151
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• 2007

Impulsive excitation on vehicle produces shock-type vibration on the seat, which has major frequencies and damping ratios dependent on the characteristics of the suspension, the tire, the seat cushion and so on. The response of single degree of freedom model to a half-sine force input was considered as simple shock-type vibration signal. Quasi-apparent-mass for fifteen subjects was measured with the shock-type vibration generated on a rigid seat mounted on the simulator, so its nonlinearity was apparently found over 6.3 Hz according to the difference of magnitude of the shock.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.25-28
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• 1996

This paper addresses the issues and difficulties encountered in developing a 12-axis measurement system for the assessment of whole-body vibration exposed from the body contact area. The contents of related survey work and the ideas from Professor Griffin in ISVR, that have led to its successful development, are introduced here. The developed 12-axis measurement system is shown to satisfy the international standards of ISO 2631 and BS 6841 in EC. This system is expected to play a key role in assessing the ride quality of passenger cars that is rapidly becomes much interest in Korean car-makers and tyre-makers.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.353-358
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• 1998

Vibrations exposured to human whole-body are transmitted through the contact area of a human body, such as feet, hip and back directly in contact with vibrating surface. they apparently leads to the decrease of human comfort, the reduction of working efficiency or normal activities, and, furthermore, causes the loss of health and safety. In this study, UH-1 vibration has been measured to produce the flight-time limitation at each mission Results of this study show that the most significant peaks appear at a main rotor blade-passage frequency and that the vibration level in ground is higher than that in airborne In addition, it is shown that the most affective aspect for the flight-time limitation is ground vibration level

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.45-51
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• 2021

The purpose of this study was to investigate the effect of applying whole body vibration exercise at 30 Hz on the thickness and mechanical properties of the erector spinae. The study population included 24 adults (11 male and 13 female) in the N region. The subjects were divided into two groups, a 30Hz whole body vibration exercise(WG, n=12) and an LSG(12 subjects). Changes in the thickness and mechanical properties of the erector spinae were analyzed before the exercises and after four and eight weeks of exercises using a two-way repeated analysis of variance with a statistical significance level of α=0.05. When there was an interaction between the groups and measurement times, post hoc analyses were conducted at a statistical significance level of α=0.01. The thickness, frequency, stiffness and strain of the erector spinae muscles were significantly different in each time period and in the interaction between time period and the group (P<0.05), and recovery was significantly different only in each time period (P<0.05). Thus, 30Hz whole body vibration exercise had a positive effect on the thickness and mechanical properties of the erector spinae. The results of this preliminary study suggest that whole body vibration exercise may find a place as a lumbar stabilization exercise in clinical practice in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.171-179
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• 2021

This study was a meta-analysis of previous studies that subjected stroke patients to the whole-body vibration exercise, in an attempt to evaluate the effectiveness of such exercise in improving their balance and walking ability. The electronic databases used for literature search were the National Assembly Library, Korean Educational Academic Information (RISS), Korean Academic Information (KISS), and Nuri Media (DBPIA). We also investigated a prior study of the whole-body vibration exercise applied to stroke patients from January 2010 to August 2020. In assessing the quality of the study, the RCT (randomized controls trials) study used the risk of bias 2 (RoB2) tool developed by the Cochrane group. Meta-analysis was performed using R software for statistical computing version 4.0.3. The results of the study confirmed that the overall effect size was 0.40, and the whole-body vibration exercise used had a moderate effect on the balance and gait of stroke patients, the effect size of balance was 0.44, and the effect size of gait was 0.36, showing a positive effect. These results indicated that the whole-body vibration exercise is an effective intervention for stroke patients, and further research is needed.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.195-201
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• 2019

PURPOSE: This study aimed to quantify the effects of whole body vibration (WBV) stimulation training on the muscle thickness and gross motor function in children with spastic cerebral palsy. METHODS: Twenty children diagnosed with spastic cerebral palsy were assigned randomly to the Whole Body Vibration (WBV) group (n=10) and control group (n=10). The WBV group received vibration therapy including five different therapy, and the control group received only five general physiotherapy sessions. After 10 weeks of intervention, the muscle thickness was measured using ultrasound, and the Gross Motor Function D and E items were evaluated. RESULTS: After the intervention, both groups showed a significant increase in muscle thickness and gross motor function (p<.05). The WBV group showed a significant increase in the quadriceps femoris and tibialis anterior muscles compared to the control group, whereas no significant increase in the gastrocnemius muscle was observed (p<.05). The WBV group showed significant improvement in the Gross Motor Function D and E scores compared to the control group (p<.05). CONCLUSION: WBV training may be a useful way of improving the lower extremity muscle strength in children with spastic cerebral palsy, which may help improve the gross motor function.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.125-131
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• 2000

This study was performed to evaluate the whole-body vibration and occupational noise for excavator drivers. Measurement, evaluation and assessment were based on the ISO 2631 and OSHA. Average vibration level was 0.65m/$s^2$(z axis) for breaking work and 0.36 m/$s^2$(z axis) for excavating work. Vibration levels during breaking work exceed the health guidance caution zone and this means that the drivers are exposed to potential health risks. Average daily noise exposure level was 86.4 dB(A) for breaking work and 84.6 dB(A) for excavating work.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.365-370
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• 1996

This paper introduces experimental results of whole-body vibration exposed through the contact area between automotive seat and human body. Such vibration experiment was carried out for five automotive seats in use and four Korean individuals. Interestingly, the quantitative assessment of the ride values of the tested seats do not only enable us to judge the footnotes the Korean technology in automotive seat has left so far, but also lead to the systematic way of improving their ride quality, in addition in Korean automotive seats raised in this paper.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.343-351
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• 2015

Objective : The purpose of this study was to investigate the effects in the muscle function following 8-week dead-lift training with Whole-body Vibration(WBV) in rehabilitation for sports players. Method : Twenty young sports players. Each subjects were randomly assigned to a resistance training with Whole-body vibration group(TG, n=10), a resistance training without Whole-body vibration group(CG, N=10). The measurements which physical fitness test and joint torque test were performed before the randomization and after the 4-week and 8-week. The WBV group performed the dynamic Dead-lift exercise on a vibration platform during one minute. The CG group performed the equal training without vibration. The WBV and CON group repeated 5 set and trained two times weekly for 8-weeks. Paired t-test was used to test for differences between the groups at baseline and after 4-weeks and 8-Weeks. And independent t-test was used to test for differences between the groups at TG and CG. All analyses were executed using SPSS software 18.0. The level of significance was set at p<.050. Results : Following the 8-Weeks training sessions, an increase in the back-muscle strength was found to be greater for the TG compared with the CG group(p<.05). Muscle endurance was significantly decreased after training than before training only for the CG(p<.05). Isometric Hip/Lumber Extension/Flextion measurement was found to be significantly greater for the TG compared with the CG group(p<.05). The finding indicates that WBV effects as an efficient training stimulus to enhance muscle function by facilitating neural control trail. Following muscle activation in motor unit synchronization of the co-contraction of the muscles. Conclusion : The results imply that the WBV training may have enhanced muscle function in rehabilitation for sports players.