• 한국해양학회지
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• v.23 no.2
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• pp.53-61
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• 1988

A capacitance wavestaff system was devised, which is suitable for the wave measurement near to surf zone. Laboratory tests show that the performance of the wavestaff is not significantly affected by the sea water characteristics such as temperature and salinity, and output signals of the wavestaff are linearly proportional to sea surface elevations. The major error source of the wavestaff system is the improper setting of the wavestaff in field experiment.

• Journal of Digital Contents Society
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• v.18 no.7
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• pp.1377-1386
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• 2017

We propose a smart ocean meteorological observation system which is capable of real-time measurement of vulnerable marine climate and oceanographic conditions. Besides, imported products have several disadvantages such that they can't be measured for a long time and can't transmit data in real time. In the proposed system, smart ocean observation digging system, it observes real-time ocean weather with data logger methods. Furthermore, we also use existing dataloggers functions with various sensors which are available in the ocean at the same time. Also, we applied the Kalman-filter algorithm to the ocean crest measurement to reduce the noise and increase the accuracy of the real-time wave height measurement. In the experiment, we experimented the proposed system with our proposed algorithms through calibration devices in the real ocean environment. Then we compared the proposed system with and without the algorithms. As a result, the system developed with a lithium iron phosphate battery that can be charged by a system used in the ocean and minimized power consumption by using an RTC based timer for optimal use. Besides, we obtained optimal battery usage and measured values through experiments based on the measurement cycle.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.4
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• pp.204-210
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• 1998

This paper presents the development of the probability density function applicable for wave heights (peak-to-trough excursions) in finite water depth including shallow water depth. The probability distribution applicable to wave heights of a non-Gaussian random process is derived based on the concept of the maximum entropy method. When wave heights are limited by breaking wave heights (or water depth) and only first and second moments of wave heights are given, the probability density function developed is closed form and expressed in terms of wave parameters such as $H_m$(mean wave height), $H_{rms}$(root-mean-square wave height), $H_b$(breaking wave height). When higher than third moment of wave heights are given, it is necessary to solve the system of nonlinear integral equations numerically using Newton-Raphson method to obtain the parameters of probability density function which is maximizing the entropy function. The probability density function thusly derived agrees very well with the histogram of wave heights in finite water depth obtained during storm. The probability density function of wave heights developed using maximum entropy method appears to be useful in estimating extreme values and statistical properties of wave heights for the design of coastal structures.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2170-2174
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• 2008

기후상승으로 해수면의 상승으로 인해 삼면이 바다로 둘러싸인 지형적 특성을 가진 우리나라 연안에 파도로부터 시설물의 보호가 중요한 요인으로 꼽히고 있다. 파의 에너지를 저감하여 연안에 위치한 시설물 보호에 많은 연구가 진행되고 있다. 여기서 다루게 될 수중방파제와 다공성 소파장치는 반사와 수심의 변화에 따른 분산효과로 입사파의 에너지 감소를 통해 연안에 위치한 구조물과 배후시설에 대한 피해를 줄이는데 주목적이 있다. 사다리꼴 수중방파제의 전 후면의 기울기를 변화시키며 장주기파의 입사파와 투과파에 대한 연구가 Chang과 Liou(2004)에 의해 연구되었고, 수직 다공성 소파장치의 두께를 변화하며 반사계수와의 상관 관계에 대한 연구가 Madsen(1983)에 의해 진행되었다. 본 연구에서는 해석해를 통해 수중방파제와 다공성 소파장치가 있는 경우에 투과파와 소파장치 전 후면에서의 처오름 높이의 변화에 대해 알아보고, 그에 따른 관계를 알아보고자 한다. 구간은 각각 수심이 일정한 지역과 변화하는 지역, 다공성 소파제가 있는 지역으로 설정하여 각 구간마다 해석해를 적용하여 파고를 측정하였다. 측정된 파고를 이용하여 투과율은 수중방파제를 통과한 입사파와 투과파의 관계를 통해 측정할 수 있다. 수중방파제를 투과한 파는 다공성 소파장치를 통과하면서 파고가 급감하는 현상을 다공성 소파장치 전 후면에서 측정되는 파고를 통해 알 수 있다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.282-283
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• 2023

항로표지 부이의 안전한 관리 및 해사 안전 서비스 제공을 위한 4채널 카메라 시스템 하드웨어를 구현하고, 항로표지 부이 근접 선박 감지, 해무 강도 측정, IMU 센서를 이용한 파고 측정 알고리즘을 구현하여 육상으로 전달하는 기능을 개발하였다

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.215-220
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• 2014

Most of studies on wave height algorithms that are using at buoys describe algorithms using double integral to determine the position data from the acceleration data measured from the accelerometer. but sometimes, it can involve some cumulative error in that process, and result in misjudgment or unstabe system. On the other hand, It is widely known that the motion of fluid particles on or underneath a linear progressive wave is periodic and elliptic. This fact is considered in this article and leads a improved algorithms with no integral processing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.513-519
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• 2016

In this study, dynamic vertical displacement of liquid in the tuned liquid column damper(TLCD) is measured by a laser Doppler vibrometer(LDV) to overcome limitations of existing sensors and to leverage noncontact sensing. Addressing advantages of noncontact measurements, operational principles of the LDV to measure velocity and displacement of a target object in motion is explained. The feasibility of application of the LDV to measurement of liquid motion in the TLCD is experimentally explored. A series of shake table tests with the TLCD are performed to determine requirements of application of the LDV. Based on the experimental results, it is proved that the LDV works under the condition of adding dye to the liquid by increasing the intensity of reflected laser and thus validity is verified by comparison with a conventional wave height meter.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1429-1433
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• 2004

본 연구에서는 쇄파대에서 정현파의 쇄파에 대해 수리모형실험과 수치모형실험을 수행하였다. 수치해석 모형에서는 Reynolds 방정식을 지배방정식으로 사용하고 난류해석을 위해 $k-\varepsilon$모델을 적용하였으며, 자유수면변위를 추적하기 위해 VOF기법을 사용하져다. 사면 및 평탄지형상에서 발생하는 쇄파양상을 서로 다르게 설정하기 위해 수심과 입사파의 주기와 파고를 변화시킨다. 발생된 정현파의 파형은 해석해와 잘 일치하였으며, 입사파와 파고계가 설치된 위치에서 측정된 파고비 $H/H_0$는 관측값과 비교해 본 길과 놀은 정확도를 나타내었다.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.166-172
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• 2012

The standard wave height measurement system is usually based on spectrum analysis for measuring wave height. The spectrum analysis is complicated because of the FFT, and the FFT is not for real time processing since it requires the saved data segments. In this paper, we carried out the performance evaluation of real-time and simpler wave height measurement system using the kalman filter and inertial sensors. The kalman filter theory is complicated, but its algorithm is simpler than the FFT and the kalman filter is used to estimate wave height by integrating acceleration data. But the accumulated error is occurred when the acceleration data is integrated. We developed the algorithm using the wind wave characteristic to decrease the accumulated error. In this paper, the performance evaluation of the wave height measurement system is carried out for various wind wave conditions. Through the experiments, we verified that it shows high measurement performance with the 3.5% margin of error in wind wave condition.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.561-568
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• 2020

Wave measurements using X-band radar have many advantages compared to other wave gauges including wave-rider buoy, P-u-v gauge and Acoustic Doppler Current Profiler (ADCP), etc.. For example, radar system has no risk of loss/damage in bad weather conditions, low maintenance cost, and provides spatial distribution of waves from deep to shallow water. This paper presents new methods for estimating significant wave heights of X-band marine radar images using Artificial Neural Network (ANN). We compared the time series of estimated significant wave heights (Hs) using various estimation methods, such as signal-to-noise ratio (${\sqrt{SNR}}$), both and ${\sqrt{SNR}}$ the peak period (TP), and ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k). The estimated significant wave heights of the X-band images were compared with wave measurement using ADCP(AWC: Acoustic Wave and Current Profiler) at Hujeong Beach, Uljin, Korea. Estimation of Hs using ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k) yields best result.