• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.587-591
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• 2012

Review of practical vibration test methods those applied in various industrial fields - such as automotive industry, electrics and electronics industry, defense industry and aerospace industry - is described on this paper. Swept sine test, random vibration test and advanced vibration techniques are explained according to their parametric values and also application fields of each test method are suggested by the characteristic of each method. For more proper application of each test method, standardized test specifications should be always reviewed and revised according to the transition of environmental factors.

• Design & Manufacturing
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• v.17 no.4
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• pp.14-23
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• 2023

The electric vehicle market is developing rapidly around the world. Also, parts of electric vehicles require precision.In order to produce high-precision motor cores,Press equipment must also have good precision. Drive motor cores are an important technology for electric vehicles. It uses a large high-speed press to mass-produce drive motor cores. Because it's a large high-speed press, there are many reasons why the precision is not good. One of the causes is vibration and noise. Recently, as environmental demands have become stricter, regulations on noise and vibration have been strengthened. It is important for press machines to reduce vibration first for sound insulation and dust proofing. This is because the "breakthrough" phenomenon occurs in the press. Dynamic precision is the precision under the load of the press, Design considering strain and stiffness shall be made. Vibration and noise may occur due to SPM of high-speed press,And vibration and noise can cause structural deformation of the press. Structural deformation of the press can affect the precision of the product.Noise and vibration also cause problems for workers and work environments. Problems with vibration and noise occur during press processing, and vibration and noise lead to damage to the mold or defects in the product. Reliability in high-quality technology must be secured with low noise and low vibration during press processing. Modular shape and deformation energy effects were analyzed through finite element analysis. In this study, a study on vibration and noise countermeasures was conducted through finite element analysis of a large high-speed press.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.11
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• pp.1166-1175
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• 2004

People in the advanced society have deep interest in such environmental problems as noise, air quality, water pollution, etc. This paper submits the result of the research on the noise In the surroundings of the butane can explosion location. First, the noise level measured in a residential area, 245 meters' away from the butane can explosion location, was 59.3 dB. Also, the noise level measured in the IGUP (International Graduate University of Peace), 300 meters' away from the explosion site, was 52.5 dB. Second, the above noise levels are lower than the level specified In the Environmental Standard (65 dB), which represented that the experiment was safe. Third, the noise level in a place away from the butane can explosion location varied in accordance with the direction of the wind. Consequently, the noise in all locations (the places where damage to people is expected) surrounding the experimental butane can explosion location was measured to identify the effect of the wind irection.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.529-534
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• 2005

This study performed an physical analysis on the characteristics of urban environmental sound divided into three parts depending on their features. Object sounds were classified into traffic sound, waster sound and spatial sound. Traffice sound was selected because it is dominant sound in urban environment, and water sound is selected because it generally supplies pleasantness in contrast to traffic sound, Finally spatial sound was considered because it represents sound in various places of city having lots of behaviors and types of sound due to them. Physcal analysis was carried out using sound quality indices based on Zwicker's loudness, $L_{Aeq}$(equivalent noise level), Ln(percentile noise level) and other acoutical attributes applied to previous study. Through the analysis, this study aims to compare the acoustical characteristics of urban environmental sound and to provide fundamental data for the evaluation of urban environmental sound.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1465-1468
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• 2006

Railway is superior to the other land transportation systems in aspects of environmental problems. Environmental problems are not considered during a preliminary feasibility study. Investment for railway is low because of low B/C(benefit/cost)ratio in the economical efficiency analysis during the preliminary feasibility study. The body of this paper studies the railway noise which can reflect environmental problems an assessment of environmental impact. The body of this paper studies the presumption of The Benefit Cost of railroad noise arresting it will be able to reflect the evaluation environmental matter of the effect which it gives to an environment.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.123-133
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• 1998

As the results of investigation, the noise level was between 60 dB and 80 dB in the area of explosion. The residents living within 1 Km would feel uncomfortable. However, hearing loss is not happened by this range. The maximum range that the human can hear is 20,000 Hz and the maximum range that the dog can hear is between 20 Hz and 40,000 Hz. The auditory range for humans to be uncomfortable toward noise is between 1,000 Hz and 2,000 Hz. As the result of this experiment, the auditory range of dog is more wide than of a human. The change of hair cells in the Corti's organ occurred when the dog was exposed to 1,000 Hz at 100 dB for 1 month. Therefore, the structure change of the ear could happen by hearing loss because of noise, but the structure change of hair cells is the worst symptom by hearing loss because of noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1444-1449
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• 2000

This environmental influence of the noise produced by a number of air-conditioner out-door units in a multi-unit housing is predicted and evaluated. The method based on Ray tracing theory and mirror image source theory is utilized. Each ventilation window in a machine room is considered as a sound source which contributes to the overall noise level of the surrounding environment. The adopted method has been found a very efficient tool to assess the environmental noise impact.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.874-875
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.751-752
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.175-176
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• 2012