• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.6
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• pp.483-492
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• 2014

Uncomfortable feelings of occupants by indoor floor impact noise in a residential building are not accurately represented by the floor impact noise from a standard impact source. It is due to the characteristics of standard impact sources, which are different from the impact forces produced by occupants. It varies significantly by impact source, and it is not easy to be replicated for testing. As a result, the indoor floor impact noise under different acoustic conditions cannot be directly compared. Using frequency response function(FRF), which represents the input-output relationships of a dynamic system, it is possible to examine the characteristics of the system. Especially, FRF can predict the response of a linear dynamic system subjected to various excitation. To determine the relationship between impact force and the corresponding response of dynamic system in residential building, the acceleration response of a concrete slab and the floor impact noise in the living room, produced by bang-machine and rubber-ball excitation, were measured. The test results are compared to the estimates based on FRF and impact force spectrum.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.27-27
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• 2011

기존에 연구 및 개발된 합성보 시스템에 대한 기초자료를 제공하고 앞으로 새로이 진행될 합성 구조 연구에 대한 방향을 제시하고자 국내 외 200여 편의 논문 및 학술기사를 기반으로 합성보에 대한 연구 및 기술 현황분석을 실시하였다. 그 결과 합성보에 대한 국내연구는 주로 실험적 연구가 63%로 해석적 연구(22%)에 비해 3배가량 높은 비율을 차지하고 있었으며, 국외의 경우 해석적 연구가 58%로 가장 높은 비중을 차지해 국내 연구방법과는 대조적인 모습을 나타냈다. 이에 앞으로는 지금까지 실시한 실험적 연구 내용을 토대로 보다 효율적인 연구 성과를 얻기 위해 해석적 연구의 기틀을 마련하는 것이 필요해 보였다. 또한 합성보 연구의 주제별 분류에 있어서도 기본적인 휨내력 평가뿐만 아니라 최근 들어, 관심이 높아진 사용자의 실제적인 생활 및 안전과 연관 있는 바닥진동, 충격음, 그리고 내화성능 등에 대한 다양한 검토가 깊이 있게 이루어져야 할 것이다. 마지막으로 기존의 구조용 재료를 대체하면서 경제적이고, 친환경성 및 재활용 재사용성 등을 고려한 미래지향적 합성구조시스템에 대한 연구 개발이 필요할 것으로 판단된다.

• KIEAE Journal
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• v.10 no.5
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• pp.187-194
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• 2010

Heavy-weight floor impact sound insulation performance criteria have been effective in Korea since the regulation which enforces the standard thickness of slabs in domestic apartment houses should be constructed by 180mm or 210mm was adopted. But every slab does not satisfy this criteria. So, review on existing floor impact sound insulation performance is needed to propose some basic materials for the revision of rating method. To achieve this goal, 63 field test data were checked and analyzed. The results of this study are as follows ; 1) The 210mm thickness slab has the characteristics of deeper level decrease above 120Hz frequency band than that of 180mm thickness slab's. 2) 27.5% of 180mm thickness slabs were satisfied the floor impact sound insulation performance criteria, whereas 65% of 210mm slabs do. 3) Among the main contribution frequency bands for the determination of single rating index, 63Hz was shown as the most contributive band in 210mm slabs. 4) In comparison of single rating index between bang machine test and ball test. there is a big difference between the two and this phenomenon is frequent in 210mm slab results. 5) Rating Methods for the analysis of cross-correlation between the amount of rating, the usefulness of the arithmetic mean could be secured.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.607-614
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• 2021

Research on elevator noise has mainly focused on the cause of its occurrence and measures to reduce it. There is still insufficient research on how to accurately measure and evaluate elevator noise. There is a measurement method established as an international standard for the measurement method, but it is also difficult to apply to high-rise apartments, and there are many cases that do not closely reflect the characteristics of elevator noise. In order to solve this problem, a study was conducted to improve the elevator noise measurement method in the current standard. In this study, the characteristics of elevator noise were closely identified. Through frequency analysis of the elevator noise and other equipment, it was verified that the elevator noise is noise with different characteristics from other equipment. Elevator noise was compared with heavy floor impact noise, which is a representative structural transmission noise, as structural transmission noise. Elevator noise was compared with heavy floor impact noise, which is a representative structural transmission noise, as structural transmission noise. The correlation between bang machine and rubber ball was found to be very high at 0.9 level. As a result, it was verified that the mid-low frequency band of the elevator noise is the main structural transmission noise and cannot be evaluated together with other equipment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1459-1462
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• 2007

In this study, vibration characteristics of concrete slab were investigated through FEM analysis. Four different floor plans with the floor area of $100{\sim}130m^2$ were chosen to be analyzed. Boundary conditions of two dimensional finite element models were determined based on the modal test results. Results showed that mode shapes were formed somewhat different according to the floor plan and the contribution of 1st mode on the floor vibration is generally the highest. Through the transient analysis, it was also found that floor plan, expecially connection of the living room with the kitchen, affected the vibration acceleration levels.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.682-686
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• 2002

It is increasing the interest on the comfortable dwelling environment, while sound Insulation performance of materials and elements used in building is falling down as they become thicker and lighter. Therefore, sound insulation performance in building has become the most important factor determining the level of housing, especially for apartment that has common wall and floor with next neighbors. This paper aims to experiment the sound insulation characteristics of floor coverings as their types and to analyse their noise reduction effect.

• Journal of KSNVE
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• v.10 no.1
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• pp.82-96
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• 2000

The purpose of this study is to figure out the relationship between the mini-laboratory and the reverberation room for the domestic floor structures which are practically constructed in apartment houses. For this purpose, seven specimen which were varied in structures and thicknesses were tested in Chonnam National University reverberation room and in the artificial mini-laboratory which is the $\farc{1}{3}$ scale model of the former. From the result of this study, it was proved that there is a good correlation between the mini-laboratory and the reverberation room for the apartment floor structures as well as floorcovering PVC. The result of this study could save the labor and the time, etc.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.92-95
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• 2005

In this study, Heavy-weight floor impact sound and vibration in concrete structures with different slab thickness have been measured in a test building. It was found that natural frequency increased according to increases of slab thickness, and acceleration level decreases. Results also show that the measurements in the 210 and 240mm slab structures are complied with the result from finite element analysis but the In and 180mm slab structures are not because the structures are constrained to the ground. Therefore, in modelling process the condition of sub-structures should be examined in relation to the boundary conditions.

• Journal of the Korea Furniture Society
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• v.24 no.4
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• pp.426-432
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• 2013

Fire resistance and impact sound insulation tests were performed for a floor assembly, of which stiffness was reinforced by shortening the span of floor joists by installing glulam beam additionally in the middle or one thirds of the original span, and which an additional ceiling component was installed apart from floor structure. By applying the isolated ceiling, timber framed floor showed 1 hour of fire resistance even in case that dead load was increased by considering cement mortar layer for radiant floor heating. Insulation performance against light and heavy impact sound was improved significantly by applying the sound absorbing layer of big mass and high elasticity in addition to the stiffness improvement and isolated ceiling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.208-213
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• 2003

The purpose of this study is to review the use of a new standard impactor, the impact ball, in evaluating heavy-weight impact noises in reinforced concrete structures. A survey revealed that children running and jumping are the major heavy-weight impact sources in multi-story residential buildings. The noise from the impact ball was measured and psychoacoustically assessed. The relationship between the noise levels and the subjective responses was also investigated. Results showed that the noise from the impact ball is similar to the noise of children running and jumping. It was also found that the noise level of the impact ball is slightly higher than the noise level of a bang machine, although the impact ball has a lower impact force.