• Journal of Biomedical Engineering Research
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• v.20 no.3
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• pp.307-314
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• 1999

This paper describes an informatlon compression of electrically evoked myoelectric signal, M-wave. This wave shows a direct response m lato-response of nerve conductlQn study and has a characteristic with finite time support. M-wave is a useful factor for investing neurodi~ease and is often desirable to have a compact description of its shape and time evolution. The aim of this paper is to show that the AR modeling IS a effective method for compressing an information of M-wave. First, AR model parameters of real M-wave are estimated. And then. they are verified by approximatmg a M-wave using estimated AR parameters and by comparing to other melhod, Hermite tlansform[4]. To concretely evaluate the proposed method, the NMSE(normalized mean square error) of approximation curves are compared. As a result, AR modeling is effective for M-wave assessment because of its capability for the information compression.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.1
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• pp.1-11
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• 2013

The aim of this study was estimated the characteristics of the wave propagation by the water level conditions using a numerical modeling method at the Wando sea area. For three cases numerical simulation on the condition of incident and incoming of the deepwater design wave and the season normal wave, the spatial distribution of the incident wave at study area were investigated. And the calculated numerical modeling results were compared with measured field wave data. According to on-site wave data measured for 18 days, the range of the significant wave height and period were 0.10~1.14 m, 4.35~8.74 sec, respectively, and the maximum wave height were 0.15~1.66 m. From the results of numerical model for offshore design wave incident, the wave height attacked from Southern-East direction at this study area were over maximum 10.5 m because of rapidly change of water depth. Numerical modeling by three water level conditions of Approxmate Lowest Low Water Level(Approx. L.L.W), Mean Sea Level(M.S.L) and Approximate Highest High Water Level(Approx. H.H.W) were practiced. From the results for the case of Approx. H.W.L, variations of wave height at the back area of islands were about 1.6 m at maximum value for the case of deepwater design wave incoming. The significant wave heights of winter season were bigger than summer under normal wave condition, the incident wave height over 5.5 m decreased by shielding effect of islands. The change of maximum wave height at summer season were distinct than winter and was about 1.2 m and 0.8 m, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.142-149
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• 2019

In this study, the past erosion history and current status in the CHUNG-UI beach of Eulwang-dong, Jung-gu, Incheon-Si, South Korea were investigated and analyzed the wave with wave-induced current to investigate the causes of coastal erosion. As a result, the significant wave height ($H_{1/3}$) was in the range of 0.07~1.57 m and the mean value was 0.21 m. The maximum wave height ($H_{max}$) was in the range of 0.02-4.76m and the mean value was 0.27m. The vertical wave height and cycles were estimated through numerical model experiments of wave transformation. The 50-year frequency design wave height ranged from 0.82m to 3.75m. As a result of the experiment of wave-induced current, wave-induced current in the CHUNG-UI beach was decreased after the installation of the Detached breakwater and the Jetty. On the other hand, when the crest elevation was increased up to 5 m, there was no significant change, but when the crest elevation was increased to 8m, strong wave-induced current occurred around the submerged breakwaters due to lowered depth of water. In addition, the main erosion of the CHUNG-UI beach is due to the intensive invasion of the wave characteristics coming from the outer sea into the white sandy beach. The deformation of the wave centered on the front of the sandy beach caused additional longshore currents flowing parallel to the sandy beach and rip currents in the transverse direction, thus confirming that the longshore sediment was moved out of the front and out of the sea. The results of this study can be used as preliminary data for the recovery of the sand and the selection of efficient erosion prevention facilities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.700-711
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• 2022

In this study, deepwater design waves were estimated for 16 wave directions and various return periods based on statistical analysis of extreme waves observed for more than 20 years at three stations (Chilbal-do, Geomun-do, Donghae). These values were compared with design waves estimated based on the omni-directional wave data. The Weibull distribution was used as the probability distribution function whose parameters were determined by the least square method. The Kolmogorov-Smirnov test was applied for the goodness of fit test. Notably, the directional design waves were smaller than the omni-directional design wave for every wave direction. The maximum 50-year wave heights for directional sectors were 7.46 m (NNE), 12.05 m (S), and 9,59 m (SSW) at Chilbal-do, Geomun-do and Donghae whereas those for uni-directional wave data were 7.91 m, 13.82 m and 10.38 m, respectively. This implied possible under-estimation of the deepwater design waves for 16 wave directions being currently used in the design of offshore and coastal structures.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.1
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• pp.55-59
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• 2005

The present data concerns the wave height distribution around the Ieodo underwater rocks and it was obtained from a 3D hydraulic model experiment which was performed in 1999 by Konkuk University and Korea Ocean Research and Development Institute. The experiment was separately undertaken for 4 different wave directions (NNW, SE, S, NNW) under which wave heights were measured at every 1m interval within the preset grid area, 16m×18m. It was observed that the wave breaking occurred on the top of the Ieodo model for all wave directions. This data may be effectively used for improving or verifying the performance of numerical wave propagation models in the area with the local breaking wave zones.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.117-121
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• 2001

For the effective development or preservation of Tokdo, the natural environments in the ambient sea area should be well investigated. The wave deformations and wave breaking in the vicinity have much affected the bottom morphology of Tokdo as well as its ecological environment. The present study investigates the wave deformations and wave breaking through a numerical model. The final goal is to provide the fundamental wave data for the effective development or preservation of Tokdo in future. The extended mild slope equation was applied to Tokdo sea area for three different deep water wave conditions (S, SSE, NNE directions). The results showed that for the S and SSE directions the wave heights in the area between the east island and the west island were very low with the level of 1~2m, but for the NNE direction they appeared pretty high with 3~4m, In the sea area near the northwest of west island, the wave heights were low to be 1~3m for all three directions of deep water wave.

• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.156-164
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• 2009

This paper aims to describe the importance of data, data collection methods, parameters to estimate the potential of wave energy and environmental impacts. The technical and economical status in wave energy conversion is outlined. Power and energy efficiency relationships are discussed. Many different types of wave-energy converters have been detailed. The progress in wave energy conversion in Malaysia is reviewed.

• 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.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.112-120
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• 2010

In this paper time series wave data measured continuously for 24 hours during a storm in Yura Sea Area are used to investigate statistical characteristics of nonlinear waves. The exceedance probability of wave height is compared using the Rayleigh distribution and the Edgeworth-Rayleigh (ER) distribution. Wave data which show stationary state for 10 hours contain 4600 waves approximately. The Gram-Chalier distribution fits the probability of wave elevation better than the Gaussian distribution. The Rayleigh ($H_{rms}$) distribution follows the exceedance probability of wave height in general and predicts the probability of freak waves well. The ER distribution overpredicts the exceedance probability of wave heights and the occurrence of freak waves. If wave data measured for 30 minute period which contains 250 waves are used, the ER distribution can predict the occurrence probability of freak waves well. But it overpredicts the probability of overall wave height If no freak wave occurs, the Rayleigh ($H_{rms}$) distribution agrees well with wave height distribution for the most of wave height ranges. The wave height distribution of freak waves of which height are less than 10 m shows similar tendency compared with freak waves greater than 10 m. The value of $H_{max}/H_{1/3}$ is related to the kurtosis of wave elevation. It seems that there exists threshold value of the kurtosis for the occurrence of freak waves.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1303-1309
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• 2015

The behavior and flow characteristics of the floating wave energy converter were analyzed by using CFD in this study. The average significant wave height was confirmed as 0.5~2.0m from the Korean coastal sea area. This study was carried out by selecting a range of 1.0~1.6m in the wave height to simulate the operations of realistic wave energy converter system. The principle of a piston wave maker was applied in order to produce periodic wave. The behavior of the wave energy converter and the state of the wave overtopping according to the generated periodic wave were confirmed through the unsteady three-dimensional flow analysis. It was found that the wave overtopping rate according to the generated periodic wave was in range of the 11.6~30.0 kg/s.