• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.2
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• pp.155-161
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• 2017

When a military vehicle is driven on a cross-country road, the occupants are exposed to vibration at a body resonance. In case that the exposure continues for too long period, the attention ability of the occupant could be affected by the vibration exposure. In the study, it was experimentally tried to find if there is a correlation between degradation of attention and vibration exposure. Two kinds of test among various psychological attention tests were employed, which were selected with considering a situation of carrying out military mission on vehicle. At the result, the searching test for controlled attention showed significant degradation in the accuracy and performance time in case of exposure at the vibration. And the attention degradation appeared to be greater when the vibration exposure increases. The dual task test for divided attention showed the difference between vibration and non-vibration condition, but showed it is insignificant for the attention to degrade by increasing exposure time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.433-438
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• 2001

This study is performed to evaluate hand-arm vibration syndrome(HA VS) of the workers in swaging process. Vibration measurement and assessment of human exposure are based on the international standard(ISO 5349). Triaxial acceleration of each operation and exposure time are measured to predict the periods before finger blanching, As results, it is found that acceleration is concerned with the diameter of pipes in swaging process, and also found that combined work is more harmful than a single operation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.4
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• pp.266-274
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• 2015

Vibration exposure of domestic high speed trains(KTX and ITX-saemaeulho) to passenger traveling on the Gyung-Bu line was measured to evaluate health effect which is based on ISO 2631-1. The vibration exposure was compared with the frequency weighted root mean square(r.m.s.) and vibration dose value(VDV) of the two trains’ vibration. It is concluded that vibration exposure of the two train during round trip of Busan-Seoul in single day is evaluated to be safe for the passenger’s health according to the health guidance caution defined on ISO 2631-1. Futhermore KTX’s vibration exposure is found to be significantly lower than ITX-saemaeulho thanks to lower vibration magnitude as well as shorter trip time.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.259-266
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• 2013

Objective: This study aims to evaluate the workloads of industrial and automobile storage battery industries and their association to biological exposure indices. Background: Occupational lead exposure at battery manufacturing workplace is the most serious problem in safety and health management. Method: We surveyed 145 workers in 3 storage battery industries. Environmental factors(lead in air, temperature, humidity and vibration)), biological exposure indices(lead in blood and zinc protoporphyrin in blood) and individual workload factors(process type, work time, task type, weight handling and restrictive clothing) were measured in each unit workplace. Results/Conclusion: Air lead concentration is statistically significant in associations with workload factors(process type, work time, task type, and restrictive clothing) and environmental factors (humidity and vibration), whereas zinc protoporphyrin in blood are significantly associated with work time and weight handling. And lead in blood is significantly associated with work time, weight handling and temperature. Application: The results of this study are expected to be a fundamental data to job design.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.3
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• pp.313-320
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• 2020

Objectives: The aim of this study is to evaluate the association between vibration exposure and skeletal muscle mass index through a single university health check-up. Methods: We used data from 134,067 male subjects who received a general health check-up or vibration exposure health check-up out of the 1,515,322 people who underwent medical check-up at a local university hospital from 2002 to 2018. Pearson correlation analysis was conducted for comparing the association between skeletal muscle mass index and demographic and hematological variables in both groups. Mixed linear model analysis after controlling demographic and hematological variables was used to analyze the differences in skeletal muscle mass index between groups at every visit over 10 years. Results: In the Pearson correlation test, the variables that showed different results when comparing the two groups were C-reactive protein (p=0.001) and glycated hemoglobin (p=0.002) in the vibration exposure group and erythrocyte sedimentation rate (p<0.001) and vitamin D (p<0.001) in the general group. After the adjustment of demographic and hematologic variables, the skeletal muscle mass index at every visit was markedly decreased in the vibration exposure group (p<0.001). Conclusions: In the vibration exposure group, the skeletal muscle mass index showed a tendency to decrease markedly over time compared to the general health check-up group, which showed that C-reactive protein and glycated hemoglobin would have an influence on skeletal muscle index in male workers exposed to vibration.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.1-16
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• 1996

This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.264-274
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• 2012

Evaluation on the environmental noise is carried out by surveying subjective response of residents with physical measurement of noise during long period in field. Particularly field survey is used to make regulations from the analysis on how many people are annoyed for specific noise level, and laboratory test used to analyze the relationship between physical parameters of noise and subjective responses. In the laboratory controlling the variables is easy but the results could be biased because the condition in room would be different with field. Most of all noise exposure time is considered to be different with real situation, and this study aimed to evaluate the subjective response by exposure time of transportation noise, by applying three kinds of variable how much they give effects on the annoyance as the exposure time is operating condition, windows type and sound level. As a result there was somewhat difference between operating type and annoyance, which is caused by the sound characteristics operated in different condition. However the window type didn't give much effect to the annoyance as much as sound type. This means that the subjective response could give similar result by exposure time even for different window types. Most of all, the main factor affecting subjective response is considered to be the sound level and the exposure time.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.5 s.98
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• pp.550-557
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• 2005

Korean 'Law of Aviation' and 'Test Method of Measuring Noise and Vibration' designate to use WECPNL metric based on $L_{max}$ measurement for the accessment of aircraft noise in Korea. However, time duration of noise event can not be considered in $L_{max}$ metric in principle, compensation on the duration has been utilized. A study was done recently to evaluate appropriate duration compensation for the accessment of military aircraft noise under current metric of WECPNL and $L_{max}$. This study was carried out to evaluate what metric is the most appropriate to express aircraft noise including time duration of single noise event, computing and comparing noise exposure with 1 second noise measurement data of military aircraft in $L_{max}$, $L_{Aeq,\;T}$ and SEL. This study shows SEL is the most appropriate noise metric for the evaluation of noise exposure with time duration such as aircraft noise without compensation. It is suggested to use SEL noise metric instead of $L_{max}$ noise metric with duration compensation for the aircraft noise accessment either military aircraft or civilian aircraft.

• IE interfaces
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• v.17 no.3
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• pp.375-383
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• 2004

The purpose of this study is to investigate the characteristics of vibration induced by the powered hand tools used in the automobile assembly lines, and estimate the prevalence of vibration syndrome. The acceleration levels of four major powered hand tools were measured using the ISO 5349 method along with the time of exposure to the vibration of the hand tools. Four-hour-energy-equivalent frequency-weighted accelerations ranged from $1.27m/s^2$ to $2.58m/s^2$, After exposure to vibration for 12.6 years, about 10% of the workers using impact ranches were expected to develop Raynaud's disease. For the workers using grinders, 16.6% of the workers were expected to develop Raynaud's disease. The results would be of help in developing the guidelines of local vibration control.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.262-266
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• 2014

Military vehicle equipped with an antenna and a shelter for operating radar has a vibration exposure during driving time. This vibration would have influence on structure of military vehicle critically. In this paper, driving stability of the military vehicle is obtained through the vibration response analysis. And, vibration level of the military vehicle satisfied the military vibration specification through analysis and comparing the MIL-STD-810G. PSD and Grms data obtained by road test can be used for vibration test specification of cabinets and electronic equipment in shelter.