• Journal of Power System Engineering
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• v.14 no.4
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• pp.29-36
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• 2010

This study was performed with 5 subjects and used three kinds of music and vibroacoustic stimuli wave based upon each kinds of music. Executing music stimulation, vibro tactile and acoustic wave stimulation to human body were performed. Then measured brain waves were analyzed under each condition including before stimulation, stimulation 1, and stimulation 2. Effects by stimulation results could be studied with experiments and summarized results are followings. 1. It may be concluded that effects on brain waves by music and vibroacoustic stimulation might differ under different situations such as stimulation types with vibroacoustic equipment, human body and mental conditions when measuring, etc.. 2. During stimuli by using music A, B, and C, the effect of $\alpha$ wave, $\beta$ wave, and SMR wave power values show same tendency to the subject c but music C had very different tendency during vibroacoustic stimuli. 3. During vibroacoustic stimuli by applying the signals of music C, because SMR wave power value was continually increased with consistency comparing to Bst, this can be estimated that an application of inducing mind concentration condition would be possible under relaxed body and mind conditions. 4. To secure data significance, all measured data need to be tested statistically whether data would be interrelated or not.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.94-101
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• 2007

This paper, we analyzed that the measured data of the radiated power spectrum of electromagnetic waves and the standing wave ratio(SWR) of the spark plug cable and spark plug. The measured data are the power strength of the electromagnetic waves radiated from the spark ignition system, the measured frequency ranges are 110 to 610MHz. The results show that the strength of radiated power spectrum and bandwidth have relation to the SWR of the the spark plug cable and spark plug, and the SWR of them is different because of the characteristics of resistor at the spark plug is different with the manufacturers. From the analyzed results, it can be concluded that the less SWR is little, the less maximum level of power spectrum is weak and bandwidth above the reference level is small.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.244-255
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• 2019

Interest in renewable energy has been increasing in recent years for many reasons, and there have been many studies on new types of wave energy converters and mechanisms for them. However, in this paper, motion characteristics of a wave energy converter with a wave activating body type is studied with an experiment. In order to conduct the experiment, a simple wave activating body type's wave energy converter is proposed. Experimental variations consist of connection type and location. The connection type controls the rotation motions of structures, and the connection location controls the distance between structures. The movement of floating structures, such as rotation, velocity, and acceleration, is measured with a potentiometer and a motion capture camera. Using the recorded data, the motion characteristics derived from the experimental variations are investigated.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.5
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• pp.343-351
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• 2012

In this study, shallow-water design waves are calculated for the return period of 10, 20, 30, and 50 years, based on the extreme value analysis of the wave measurement data at Gangneung beach. These values are compared with the results of SWAN simulation with the boundary condition of the deep-water design waves of the corresponding return periods at the Gangneung sea area provided by the Fisheries Agency (FA, 1988) and Korea Ocean Research & Development Institute (KORDI, 2005). It is found that the shallow-water wave heights at Gangneung beach calculated by the deep-water design waves were significantly less than the observation data. As the return period becomes higher, the significant wave heights obtained by the extreme value analysis becomes higher than those computed by SWAN with the deep-water design waves of the corresponding return periods. KORDI computed the hindcast wave data from January 2004 to August 2008 by WAM with a finer-grid mesh system than those of previous studies. Comparisons of the wave hindcast results with the wave observation show that the reproducibility of the winter-season storm wave was considerably improved compared to the hindcast data from 1979 to 2003. Hereafter, it is necessary to carry out hindcast wave data for the years before 2004 using WAM with the finer-grid mesh system and to supplement the deep-water design wave.

• Water for future
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• v.20 no.1
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• pp.49-54
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• 1987

A numerical analysis of the characteristics of wave reflection over rippled beds (sand bars) was carried out By Boundary Element Method(B.E.M) using linear elements. It is assumed that the incident wave is normal and oblique to the rippled beds and the wave may be and the escribed by two-dimensional linear theory. The accuracy of the computational scheme is investigated by comparing the laboratory data, the analytic measured results of the other researchers. The B.E.M results for the normal incident wave is held for the mechanism of the resonant Bragg reflection at the point where the wave length of the bottom undulation is one half the wave length of the surface wave.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.413-420
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• 2008

Wave force is an important factor which gives a direct affect to stability of the rubble mound breakwater. Particularly wave force has been considered as the main cause of displacement for replaced rubble mound breakwater which permits a little displacement to some degree. But the effect on displacement by wave force has not been considered and reflected in design. Therefore in this study, we compared numerical analysis displacement with field measured displacement so that the effect of wave force on displacement can be reflected in design. Result of the numerical analysis displacement was well consistent with field measured displacement data.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.93-99
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• 2011

In this study, a series of laboratory experiments are carried out to analyze fluid behaviors around multi-arranged (2 pieces) floating breakwaters with various parameters such as distance between structures, wave periods and steepness. The rate of wave transmission is shown to be affected directly by wave periods of incident waves and the breakwaters with multi-arranged structures show the highest rate of wave protection compared with other cases. The velocity fields around the breakwaters are measured by using the Laser Doppler Velocimetry system. The transmission coefficients are also measured in laboratory experiments. Finally, laboratory observed data are compared with numerical experimental results and analyzed in detail.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.671-674
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• 2007

In this paper, the EM wave absorber was designed and fabricated for ETC system, because ETC system has some problems including signal error and system-to-system interference. We fabricated some samples in different composition ratio of MnZn-ferrite, Carbon and CPE, confirmed that optimum composition ratio of Mn2n-ferrite, Carbon, CPE was 40 : 15 : 45 wt%. Complex relative permittivity and complex relative permeability was calculated by the measured data. And absorption abilities were simulated according to different thickness of the EM wave absorbers using complex relative permittivity and permeability. The EM wave absorber was fabricated based on simulated data Simulated and measured values agree well. As a result, the developed EM wave absorber has a thickness of 3.38 mm and absorption ability over 20 dB at 5.8 GHz.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.204-215
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• 2020

People who have sleep disorders such as insomnia take a long time to get to sleep, namely sleep latency. In order to reduce it, effective stimulations and environments to induce sleep such as ASMR or pink noise are necessary. However these have different effects and preferences for each individual. Therefore customized service and control for the sleep induction will be provide to him/her. In this paper, we proposed SIS control system which provides selectively sound control among various kinds of ASMR and pink noise according to sleep state measured from brain wave data for an individual. In order to verify the effectiveness of the system, we had conducted totally 30 experiments for 5 people, and all EEG data measured from all the people during sleep. An average of 3.7 hours was spent per experiment. In comparison experiments with and without sound control for sleep induction, the latency time was reduced by an average of 8 minutes as well as delta waves and theta waves, which appear only in deep sleep, are increased by 21%.

• The Journal of Engineering Geology
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• v.11 no.2
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• pp.215-227
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• 2001

The Okchon Formation and the Mesozoic granite of the Boeun, Chungbuk are compared in terms of seismic wave velocities estimated from the field experiment, and seismic wave velocities in 3-D measured from the rock specimen. P-wave velocity for the field data ranges from 861 m/s (Guryongsan-2 Formation) to 2697m/s (Bulguksa Granite). P-wave anisotropy also ranges from 46% (Changri Formation) to 81% (Bulguksa Granite), with an average value of 68.5%. P-wave velocities for the rock specimens from Guryongsan-1, Guryongsan-2, Changri, and Munjuri Formations are greater than 5000m/s. S-wave velocities for those specimens are approximately 3500m/s, which is 3-5 times grater than the ones estimated from the field experimental data. P-wave anisotropy for the specimens from Bulguksa Granite and Guryongsan-1 Formation exceeds 60%, which is compared to 30% for the other specimens. This value is much smaller than average P-wave anisotropy (69.5%) for the field data. It is suggested that velocity difference, associated with the propagation direction, is much greater for the field data than for the specimens.