• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.473-478
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• 2007

The energy efficiency and environment-friendly aspect of the railway system would be superior to other on-land transportation systems. In a preliminary feasibility study stage, the energy efficiency and problems related with environment are usually not considered. The railway noise and vibration which could be reasons of environmental problems are focused and studied in this paper. The investment for railway systems could be encouraged by the considering of main environmental elements evaluated with the modified noise and vibration standard for environment-friendly railway construction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.875-878
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• 2006

In the case of a vibration sensitive equipment, it require a vibration free environment to provide its proper function, therefore, it is very important to predict precisely vibration environment of microelectronics production facility due to adjacent blast work. However, it is not easy to evaluate a quantitative vibration response of structure due blast because it can be determined by the characteristics of vibration sources, propagation through rock and soil and dynamic properties of building. In this paper, vibration influence evaluation of micro-electronic Production building induced from adjacent blast activity was performed by real measurement data obtained on ground and structure at same time. And blast vibration allowable limit on ground was supposed by measurement data analysis in order to avoid operation error of precision equipments

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.107-112
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• 2007

The vibration generated on shipboard is very important because it greatly affects on the comfortable mind of passenger and working conditions of crews. Shipboard vibration is closely concerned with the development of propulsion method and the type of main engine to decide speed of ship. To make the propulsion power, the main engine of ship have continuous explosion process in engine room, so the shipboard vibration is generated. The shipboard vibration causes the physiological and psychological damages to human body. In the case of the human body exposed to the shipboard vibration, the evaluation of human exposure to whole-body vibration is prescribed in ISO 6954 : 2000(E). In this paper, to evaluate the shipboard working environment, two kinds of vibration levels onboard ship were measured and compared with one another between engine rooms, engine control rooms and wheel house by the regulation of ISO 6954 : 2000(E).

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.497-506
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• 2020

CA mortar layer disengagement will give rise to the overall structural changes of the track and variation in the vibration form of the ballastless track. By establishing a vehicle-track-viaduct coupling analysis and calculation model, it is possible to analyze the CRTS-I type track structure vibration response while the track slab is disengaging with the power flow evaluation method, to compare the two disengaging types, namely partial contact loss at one edge beneath track slab and partial contact loss at midpoint beneath track slab. It can also study how the length of disengaging influences the track structures vibration power. It is showed that when the partial contact loss beneath track slab, and the relative vibration energy level between the rail and the track slab increases significantly within [10, 200]Hz with the same disengaging length, the partial contact loss at one edge beneath track slab has more prominent influence on the vibration power than the partial contact loss at midpoint beneath track slab. With the increase of disengaging length, the relative vibration energy level of the track slab grows sharply, but it will change significantly when it reaches 1.56 m. Little effect will be caused by the relative vibration energy level of the viaduct. The partial contact loss beneath the track slab will cause more power distribution and transmission between the trail and track slab, and will then affect the service life of the rail and track slab.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.927-932
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• 2000

Recently, construction vibration has caused annoyance for a number of dwellers in nearby construction field and that induced from operating of large construction equipment, has become a very serious issue in our living environment. But, construction vibration standard of our living environment. But construction vibration standard of our country is efficient. Especially, directly blow method(diesel piling method, oil pressure method, etc) has caused much problems of highly impactive vibration. Construction works, in order to solve these problem, will be used SIP(Soilcement Injected Precast Pile) method of low vibration equipment. In this point, this study attempts to survey on the characteristics of piling vibration by SIP method for various earth conditions in construction field. And this study intends to get the basic data to establish a standard about construction vibration.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.369-379
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• 2013

Noise and vibration problems at the construction site, expansion of construction scale and frequency of urban construction is increased, has given the damage to local residents. Also, the result of civil complaint about noise and vibration that occurred in 2011 was 56,244; it is showing an increasing trend of more than 4% annually. In particular, the construction noise and vibration, the civil complaints of around construction site accounts for 64.6%(36,353), are harmful to the tranquility of living environment. As a result, the government has managed to strengthen the regulatory standard of construction noise (65dB(A), Day-time) from 2011. However, the regulatory standard of construction noise and vibration does not meet and also complaints related the construction noise and vibration not decreased. Because the management system can be applied to the construction site is insufficient and a shortage of manpower. In this study, investigated the status and problems of the regulatory standards related to construction noise and vibration, we propose an efficient management plan of construction noise and vibration.

• Structural Engineering and Mechanics
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• v.72 no.4
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• pp.421-432
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• 2019

In high-speed railway (HSR) system, the structure-borne noise inside viaduct at low frequency has been extensively investigated for its mitigation as a research hotspot owing to its harm to the nearby residents. This study proposed a novel acoustic optimization method for declining the structure-borne noise in viaduct-like structures by separating the acoustic contribution of each structural component in the measured acoustic field. The structural vibration and related acoustic sourcing, propagation, and radiation characteristics for the viaduct box girder under passing vehicle loading are studied by incorporating Finite Element Method (FEM) with Modal Acoustic Vector (MAV) analysis. Based on the Modal Acoustic Transfer Vector (MATV), the structural vibration mode that contributes maximum to the structure-borne noise shall be hereinafter filtered for the acoustic radiation. With vibration mode shapes, the locations of maximum amplitudes for being ribbed to mitigate the structure-borne noise are then obtained, and the structure-borne noise mitigation performance shall be eventually analyzed regarding to the ribbing conduction. The results demonstrate that the structural vibration and structure-borne noise of the viaduct box girder mainly occupy both in the range within 100 Hz, and the dominant frequency bands both are [31.5, 80] Hz. The peak frequency for the structure-borne noise of the viaduct box girder is mainly caused by $16^{th}$ and $62^{th}$ vibration modes; these two mode shapes mainly reflect the local vibration of the wing plate and top plate. By introducing web plate at the maximum amplitude of main mode shapes that contribute most to the acoustic modal contribution factors, the acoustic pressure peaks at the field-testing points are hereinafter obviously declined, this implies that the structure-borne noise mitigation performance is relatively promising for the viaduct.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.25-31
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• 2021

The semiconductor and display equipment demands an ultra-fine precision of several nm to several ㎛, and the scale is getting smaller due to the explosive development. The manufacturing process equipment for such products with ultra-fine precision is very sensitive to ultra-small vibrations flowing from the floor, resulting in problems of production defects and yield degradation. The vibration criteria are a standard that regulates the vibration environment of the floor where such precision process equipment will be installed. The BBN vibration criteria defined the allowable vibration velocity level in the frequency domain with a flat and inclined line and presented a rating according to it. However, the actual vibration criteria have appeared with various magnitudes in the frequency domain according to the dynamic characteristics of individual equipment. In this study, the relationship between the relative motion of two major points in the equipment and the vibration magnitude of the floor is presented using the frequency response function of a simple 3-DOF model. It is describing the magnitudes according to the frequency of the floor vibration that guarantees the allowable relative motion and this can be used as the vibration criteria. In order to obtain the vibration criteria experimentally a method of extracting through a modal test was introduced and verified analytically. It provides vulnerable frequency and magnitude to floor vibration in consideration of the dynamic characteristics of individual equipment. And it is possible to know necessary to improve the dynamic characteristics of the equipment, and it can be used to check the vibration compatibility of the place where the equipment will be installed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.7
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• pp.517-524
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• 2014

Micro-vibration induced by on-board equipments such as fly-wheel and cryogenic cooler with mechanical moving parts affects the image quality of high-resolution observation satellite. Micro-vibration isolation system has been widely used for enhancing the pointing performance of observation satellites. In general, the micro-vibration isolation system requires a launch locking mechanism additionally to guarantee the structural safety of mission payloads supported by the isolation system with low stiffness under launch environment. In this study, we propose a passive launch and on-orbit vibration isolation system using shape memory alloy mesh washers for the micro-vibration isolation of spaceborne compressor, which does not require the additional launch locking mechanism. The basic characteristics of the isolator were measured in static and free vibration tests of the isolator, and a simple equivalent model of the isolator was proposed. The effectiveness of the isolator design in a launch environment was demonstrated through sine vibration, random vibration and shock tests.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.803-808
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• 2011

The shipboard working environment of navy vessel is very inferior to the ground working environment. For this reason, the crew of a navy vessel suffer from an occupational disease such as lumbar pain, hearing loss, etc. Although standard for navy vessel's environmental vibration is applied, the criterion of the environmental vibration is too high. So it doesn't help to improve habitability of crew. In this study, for improving its habitability of crew, the current vibration level of navy vessel was examined and the standard of navy vessel's environmental vibration was investigated.