• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.88-93
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• 2012

Recently data centers are being established or expanded according to IT industry development. A data center must be to install emergency generator. In case of the data center located the densely populated urban area, the operating noise of an emergency generator can be the cause of complains. In this case, in order to establish an effective and economical measure and quantitative and thorough review is needed by noise & vibration specialists. To achieve this, in this study, it is suggested noise reduction measure using noise measurement data and 3D noise analysis method.

• Journal of Environmental Impact Assessment
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• v.17 no.6
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• pp.381-391
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• 2008

The instances of the damage to livestock are increasing with frequent environmental disputes on the noise and vibration. This study analyzed 134 open cases dealing with the environmental disputes on livestock damaged by noise and vibration, and being intervened by National Environmental Dispute Resolution Commission. The environmental disputes on the noise and vibration account for 86% of all the disputes, and cases of the consequent damages to livestock have increased. As shown in the 134 cases, pig is the most lethal livestock attacked by the noise and vibration. During last 10 years, 89% of the noise damages hurting the livestock resulted from the noises pertaining to construction and 58% was due to the noise damages from the road constructions. The noise levels in the range of 70~80 dB(A) and the vibration levels of 70~75 dB(V) caused most of the disputes. The average rate of reimbursement for the livestock damages for the last 10 years was higher than the average rate of reimbursement of the total disputes intervened by National Dispute Resolution Commission.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.718-723
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• 2005

The purpose of this study is to present a fundamental data for evaluating aircraft noise of building site development. By the field experiments and the predicted equal noise level contours using the INM program, actual condition in the building site development arranged district was investigated. In order to get the results, Analysis of factors effected on noise level, sound level on the rate of increase to aircraft demand and difference on the aircraft noise levels according to floor level in apartment house was carried out. As a result the influence of the take-off and landing direction were appeared greatly. The influences of the height at receiving point, movement number of aircraft and increase to aircraft demand were appeared small And the influence of 1 day average WECPNL must be considered.

• Journal of Environmental Impact Assessment
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• v.18 no.3
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• pp.143-150
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• 2009

The present study investigates the effects of the flight paths of military aircraft on noise map and its WECPNL(Weighted Equivalent Continuous Perceived Noise Level) distribution. Aircraft noise modeling and simulation have been performed on a Korean military air base by means of INM(Integrated Noise Model) with the input data of airfield location, aircraft specifications, flight paths and aircraft's operation schedules. The result of noise modelling has been verified in comparison with the result of measured noise level. The flight path of military aircraft, as the key parameter of the present study, was modeled by combining takeoff, overfly, approach and touch-and-go modes. The present INM simulations have been conducted for various flight path cases with different takeoff, approach modes and overfly modes. The simulation results showed that the change of flight path can remarkably affect the noise influence region and the WECPNL distribution around the airfield.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.1015-1020
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• 2004

The road traffic noise becomes aggravated due to the rapid increase of vehicles. It has a great effect on the dwelling environment. Therefore we investigate the characteristics and sources of the road traffic noise through grasping the status of the road traffic noise. This paper is concerned with the description of the various factors affecting the generation and propagation of outdoor traffic noise. It is particularly concerned with the mathematical interpretation of these processes and the resulting development of prediction techniques which are now broadly used for both the environment impact assessment of road traffic noise and the planning and design of roads and adjoining land use.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.296-299
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• 2006

This study is about correlation between WECPNL and other units such as NNI, Leq and Ldn for aircraft noise that ere measured by automatic measuring system networks for grasping the effect of aircraft noise and investigated the aircraft noise level from 2004 to 2005 nearby 10 airports in Korea. It is very important to find the relationship among the various noise units, because exchange between the results of many other nation's study can improve the assessment and mitigation study of the aircraft noise. Correlation between WECPNL and M is better than one between WECPNL and Leq and between WECPNL and Ldn, because WECPNL and NNI are based on the PNL.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.187-191
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• 2001

Sound quality engineering in automobile noise applications has become more and more important under the current quiet driving condition that the interior noise level is below 65 dBA, because various noise components masked under high noise level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on automobile sounds and noises. In particular, the interior sound quality has been one of research fields that can give high-quality feature to automobile products. Although many works related to the interior sound quality have been progressed or completed in foreign countries, limited research results are presented in the country. In the study, as a base step necessary to objective assessments on car interior noises, subjective assessments are performed with 20 subjects. For this purpose, perceptual adjectives suitable to the assessment of acceleration noises are selected as assessment scales through questionnaire procedures using 35 subjects. Mean values and standard deviations are calculated for noises created through digital filtering of acceleration noises measured. In addition, the correlation analysis and the factor analysis are carried out to investigate the dependence of the assessment scales selected.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.428-436
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• 2006

The assessment of an urban site depends on the way whether it responds to multiple needs such as functionality, aesthetic and complex comfort of acoustic, thermal, lighting and air quality etc. This study aims to investigate the assessment of various urban soundscapes in the sense of acoustic amenity by the questionnaires. As a result, acoustic amenity assessment was influenced by the non-acoustic factors such as environment assessment of visual, thermal, air quality etc. In the sense of sound quality, urban environmental sound was interpreted as 3 factors of strength, evolution of time, spacial localization. So these factors would be considered in the new assessment method for acoustic amenity. And it was shown that the subjects tend to perceive the noise level less than $3{\sim}5dB\;L_{eqA}$ according to the urban landscapes under the similar noise exposure level.

• Journal of Environmental Impact Assessment
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• v.20 no.2
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• pp.123-131
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• 2011

The objective of this study is to prepare the effective management plan of environmental noise with a noise map, and the guideline on the management plan of environmental noise was suggested through the review of existing application examples. The management plan of environmental noise with a noise map includes the practical contents in the stages of subdivision of management areas, establishment of reduction measures, opinion collection, post investigation, and reformulation of management plan. First, the classification of management regions is performed considering the excess degree of noise standard and the facility type in the phase of subdivision of management areas. Second, the optimal management plan is established through the investigation of regional characteristics and various noise reduction measures in the phase of establishment of reduction measures, which includes the examination of noise reduction effects with a noise map and the budget planning with the costing of noise reduction measures. Third, the opinion survey with a local resident and a expert is carried out in order to prove the validity of the management plan in the phase of opinion collection, and the management plan is modified with gathered opinions. Fourth, the post examination plan with noise measurement is performed in order to verify the real effect of noise reduction measures according to the management plan in the phase of post investigation. Finally, the amendment of the management plan as well as the improvement of a noise map is carried out at a regular cycle in the phase of reformulation of management plan.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.569-576
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• 2019

Objectives: The main purpose of this study was to assess firefighters' daily personal noise exposure and explore noise levels related to specific tasks and their contributions to total noise exposure using 24-hour full-shift noise exposure measurements with task-based data. Methods: Noise exposure was assessed for eight firefighters (two rescuers, two drivers, and four suppressors) using time-activity diaries. We collected a total of 24 full-shift personal noise sample sets (three samples per a firefighter). The 24-hour shift-adjusted daily personal noise exposure level (L_ep,d), eight weekly personal noise exposures (L_eq,w), and 40 task-specific L_eq values (L_{eq activity}) were calculated via the ISO/NIOSH method. Results: The firefighter noise-sample datasets showed that most firefighters are exposed to noise levels above EU recommended levels at a low-action value. The highest noise exposure was for rescuers, followed by drivers and suppressors. Noise measurements with time-at-task information revealed that 82.3% of noise exposure occurred when checking equipment and responding to fire or emergency calls. Conclusions: The results indicate that firefighters are at risk of noise-induced hearing loss. Therefore, efforts at noise-control are necessary for their protection. This task-specific noise exposure assessment also shows that protective measures should be focused on certain tasks, such as checking and testing equipment.