• 대한인간공학회지
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• 제32권4호
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• pp.345-353
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• 2013

Objective: This research measured physiological and psychological effects of Vibroacoustic stimulation(VA) to scapular and sacrum of supine position on the mattress. Background: When vibroacoustic stimulation applies to human body, it has a positive influence on physiological and psychological effects by stimulating the organs, tissues and cells of whole body. Method: This experiment was conducted to 10 normal males in two conditions: no stimulation and vibroacoustic stimulation. No stimulation experiment was executed as a supine position for 30 minutes without any vibrational stimulus, while vibroacoustic stimulation was transmitted by the vibrational speaker, which uses 40Hz frequency. Subjects had a laser Doppler flowmeter probe in scapular, sacrum, and also had 8 channel electroencephalogram(EEG) measurement sensor in the scalp. Blood pressure and skin temperature were measured in two conditions with an underlying posture for 30 minutes. Additionally, blood flow rate and EEG were measured before and after for two minutes on two conditions. Results: According to the vibroacoustic stimulation, blood flow rate and skin temperature were increased, while blood pressure was decreased. When using vibroacoustic stimulation compared to no stimulation, blood flow rate went approximately two times higher, and skin temperature also higher 3~4 times. Furthermore, the relative alpha power of brain wave was significantly increased when we applied to vibroacoustic stimulation. Conclusion: This experiment tested the VAT embedded in mattress in two conditions. According to this experiment, VAT decreases blood pressure, improves not only a physiological effect on blood flow rate as well as skin temperature, but also psychological functions by increasing relative alpha power. Application: The results of the publishing trend analysis might help physiological and psychological effects of vibroacoustic stimulation.

• 동력기계공학회지
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• 제14권4호
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• pp.29-36
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• 2010

인체에 음향진동장치에 의하여 자극을 가하였을 경우 영향을 고찰한다. 5명의 건강한 남자 대학생을 대상으로 하여, 3가지 형태의 음악을 음향과 진동자극의 신호원으로 사용해서 실험을 행하였다. 모든 피험자에 대하여, 자극 전, 음악자극, 진동자극, 자극 후로 나누어 뇌파를 측정하였다. 실험의 모든 피험자의 측정 데이터의 t-검정을 수행하여 유의성이 있는 데이터에 한하여 뇌파를 고찰하였다. 결과로서, 음악과 음향파와 진동자극이 뇌파에 미치는 영향은 음향진동장치에 따른 진동자극 형태, 피험자의 몸과 정신 상태에 따라 현저하게 달라질 수 있다는 것을 알 수 있다. 그리고 적절한 음악과 음향진동장치를 사용하여 특정의 뇌파 상태를 유도 할 수 있음을 확인하였다.

• 동력기계공학회지
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• 제11권2호
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• pp.32-37
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• 2007

The present study describes the effects of music and vibroacoustic stimuli to the relaxation of human body. We have carried out the experiment on 6 human subjects of which are composed 3 men and 3 women. We have investigated the electroencephalogram(EEG) of all subjects before and after the stimuli of which are made a strong noise or the meditatiom music and the acoustic vibration. The vibroacoustic device has transmitted meditation music as vibration between 20Hz and 250Hz to the body. From the experimental results, we made sure the effects that the meditation music and vibroacoustic stimuli influenced the stress reduction of human body for good as alpha wave was increased continuously during the good stimuli and after that.

• Coupled systems mechanics
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• 제8권6호
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• pp.473-488
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• 2019

The present work is the study of mechanical behavior due to variation of the geometrical parameters in the core of the sandwich honeycomb panel. This study has allowed us to increase or decrease the strains and stresses of the panel, in changing the angle of alveolus, as explained and described below. In taking into consideration the results obtained previously to improve the mechanical properties and increase the adhesion of different parts of the panel, without changing the adhesive, we have conceived two new models, in increasing the contact surfaces in boundary of each part of the panel and giving a conical hexagonal shape in his corp.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1063-1068
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• 2007

개인마다 소음, 음악과 음향진동 자극에 대한 인체의 반응은 상당한 차이가 발생하는 것을 고려하여 뇌파 파워의 상대적인 비율로 비교.고찰하였다. 우선 강한 소음 자극에 대한 뇌파의 변화는 긴장과 스트레스 증가를 의미하는 베타파의 증가 및 긴장완화와 안정을 의미하는 알파파의 감소를 보였고, 좋은 자극에 대해서는 그 반대의 효과를 보였다. 즉, 좋은 자극에 의한 스트레스저감의 효과가 있음을 확인하였다. 자극 후의 변화에서는 좋은 자극시와 마찬가지로 대체로 알파파가 증가하는 경향이 있지만 이와 반대의 경우도 발생하고있어 이 역시 개인차가 있음을 알았다.

• Physical Therapy Rehabilitation Science
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• 제11권3호
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• pp.321-328
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• 2022

Objective: The purpose of this study was to investigate the effect of neck stabilization exercise combined with vibroacoustic sound on patients with chronic neck pain and tension-type headache. Design: Two group pre test - post test design. Methods: 36 patients participated. Headache impact test-6(HIT-6), numerical rating scale(NRS) and muscle characteristics were measured at pre-post test. Participants divided into vibroacoustic sound group(VSG, n=18), control group(CG, n=18). VSG performed neck stabilization exercise and vibroacoustic sound stimulation. CG performed neck stabilization exercise. Both groups participated 3 times a week for a total of 4 weeks. Results: NRS showed a significant difference before and after intervention in both groups (p<0.05). HIT-6 showed a significant difference before and after intervention in the VSG group (p<0.05). Muscle tone showed a significant difference before and after intervention in the experimental group (p<0.05). There was no significant difference in muscle stiffness and muscle elasticity before and after the intervention in both groups (p>0.05). Conclusions: Based on the results of the study, it is thought that sonic vibroacoustic sound can be established as an effective treatment tool through a study applied to various diseases and symptoms.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.644-647
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• 2007

In this paper, we present our method of controlling the transmission path of compressor vibration to reduce the vibroacoustic of refrigerator. Firstly, to reduce the vibroacoustic radiated from compressor _ mount system, main transmission path was found experimentally and applied partial contact to transmission path to minimize the transmissibility from compressor operation to base plate. In order to verify our method, we designed changing of the connection part between grommet and base plate. Through experiment with modified connection part, we certificate experimentally the noise reduction of refrigerator. Finally, we apply previous connection part to grommet inner shape to enhance the effect of the system. From experimental results, we make certain the possibility of noise reduction of refrigerator through this approach.

• Structural Engineering and Mechanics
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• 제65권4호
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• pp.359-368
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• 2018

Dynamic analysis of complex and large structures may be costly from a numerical point of view. For coupled vibroacoustic finite element models, the importance of reducing the size becomes obvious because the fluid degrees of freedom must be added to the structural ones. In this paper, a component mode synthesis method is proposed for large vibroacoustic interaction problems. This method couples fluid subdomains and dynamical substructuring of Craig and Bampton type. The acoustic formulation is written in terms of the velocity potential, which implies several advantages: coupled algebraic systems remain symmetric, and a potential formulation allows a direct extension of Craig and Bampton's method to acoustics. Those properties make the proposed method easy to implement in an existing finite element code because the local numerical treatment of substructures and fluid subdomains is undifferentiated. Test cases are then presented for axisymmetric geometries. Numerical results tend to prove the validity and the efficiency of the proposed method.

• 한국항공우주학회지
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• 제34권2호
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• pp.82-89
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• 2006

항공기의 플러터 및 진동소음 특성은 장기간에 걸친 다양한 비행시험을 통해서만 획득 가능하며, 생성된 방대한 양의 데이터를 효율적으로 축적하기 위해서는 특별히 설계된 데이터베이스 시스템이 필요하다. 이에 따라 MS-Access를 기반으로 하여 T-50 고등훈련기 비행시험 시 측정된 플러터/진동소음 환경 데이터를 처리하는 데이터베이스 시스템을 개발하였다. 개발된 시스템은 항공기 비행시험과 관련된 자료 항목, 관련 항목으로 구성된 테이블, 그리고 작성된 테이블들을 논리적으로 연결한 관계형 데이터베이스로 구성되며, 비쥬얼 베이직과 구조적 질의어를 이용한 데이터 검색 GUI(Graphic User Interface)를 구현하여 직관적인 검색이 가능하도록 되어 있다. 개발된 시스템을 이용하여 플러터/진동소음 데이터의 축적 및 요구도 검증에 효과적으로 활용하였다.

• Steel and Composite Structures
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• 제28권5호
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• pp.629-639
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• 2018

In this paper, the vibroacoustic responses of baffled laminated composite sandwich flat panel structure under the influence of harmonic excitation are studied numerically using a novel higher-order coupled finite-boundary element model. A numerical scheme for the vibrating plate has been developed in the frame work of the higher-order mid-plane kinematics and the eigen frequencies are obtained by employing suitable finite element steps. The acoustic responses are then computed by solving the Helmholtz wave equation using boundary element method coupled with the structural finite elements. The proposed scheme has been implemented via an own MATLAB base code to compute the desired responses. The validity of the present model is established from the conformance of the current natural frequencies and the radiated sound power with the available benchmark solutions. The model is further utilized to scrutinize the influence of core-to-face thickness ratio, modular ratio, lamination scheme and the support condition on the sound radiation characteristics of the vibrating sandwich flats panel. It can be concluded that the present scheme is not only accurate but also efficient and simple in providing solutions of the coupled vibroacoustic response of laminated composite sandwich plates.