• 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.

• 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 Ship and Ocean Technology
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• v.6 no.4
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• pp.13-18
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• 2002

Active control has been partly applied to suppress the re-reflecting waves in wave basin with plunger-type wave maker to obtain desirable waves. This limitation comes from the non-confirmable theoretical background to the control algorithm. This paper proposes control logic to overcome this drawback, based on the impulse response function for propagating waves between control input and the wave height. The performances have been verified as reasonable in practical application by comparing with the propagating wave components in numerical wave basin, using wave decomposition method. Moreover, the control logic can also give useful wave-absorbing performance after cessation of wave generation.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.100-105
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• 2013

This paper presents a sea surface reconstruction method that uses measured radar images by applying filtering techniques and identifying wave characteristics of the surrounding the Ieodo ocean research station using WaveFinder (X-band wave measurement radar), which is installed in the station. In addition, the results obtained from real radar images are used to verify the reconstructed sea surface. WaveFinder is a marine system that was developed to measure wave information in real time. The WaveFinder installed in the station could acquire sequent images for the sea surface at constant time intervals to obtain real time information (Wave height, mean wave period, wave directionality, etc.) for the wave by getting a three-dimensional spectrum by applying an FFT algorithm to the acquired sequent images and wave dispersion relation. In particular, we found the wave height using the SNR (Signal to noise ratio) of the acquired images. The wave information measured by WaveFinder could be verified by comparing and analyzing the results measured using the wave measurement instrument (Sea level monitor) in the station. Additionally, the wave field around the station could be reconstructed through the three-dimensional spectrum and the inverse FFT filtering from the analyzed results for the measured radar images. We verified the applicability of the sea surface reconstruction method by comparing the measured and simulated sea surfaces.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1055-1062
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• 2015

A GPS based wave height meter system is proposed in this paper. The proposed system uses a dual-frequency measurements, a precise GPS satellite information and a PPP-based navigation algorithm to estimate the position with high accuracy. This method does not need to receive corrections from the reference stations. Therefore, unlike RTK based wave meter, regardless of the distance to the reference stations, it is possible to estimate position with high accuracy. This system is very simple and accurate system, but accelerometer-based system requires the other sensors such as GPS. Because position error is accumulated in the accelerometer system and must be removed periodically for high accuracy. In order to get the measurements and test the proposed wave height meter system, a buoy equipped with the test platform is installed on the sea near by Jukbyeon habor in Uljin, Korea. Then, to evaluate the performance, compares built-in commercial wave height meter with proposed system.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.227-232
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• 1995

A new evaluation procedure for calculating the Jacobian elliptic parameter is presented. This procedure is useful in calculating the trajectory for cnoidal wave generation. Upon specification of water depth, the wave height and either the wave period or the wavelength, the presented algorithm uses the Newton-Raphson method and the arithmetic and geometric-mean scales to calculate the profile directly, without trial and error procedures or look-up in tables. It is shown that the algorithm provides equally accurate result as the ad hoc methods previously used.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.243-250
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• 2022

The purpose of this study was to propose technology to detect the wave in the image in real-time, and calculate the height of the wave-overtopping through image analysis using artificial intelligence. It was confirmed that the proposed wave overtopping detection system proposed in this study could detect the occurring of wave overtopping, even in severe weather and at night in real-time. In particular, a filtering algorithm for determining if the wave overtopping event was used, to improve the accuracy of detecting the occurrence of wave overtopping, based on a convolutional neural networks to catch the wave overtopping in CCTV images in real-time. As a result, the accuracy of the wave overtopping detection through AP50 was reviewed as 59.6%, and the speed of the overtaking detection model was 70fps based on GPU, confirming that accuracy and speed are suitable for real-time wave overtopping detection.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.711-722
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• 2020

An optimization framework using genetic algorithms has been developed towards an automated parametric optimization of the Octabuoy semi-submersible design. Compared with deep draft production units, the design of the shallow draught Octabuoy semi-submersible provides a floating system with improved motion characteristics, being less susceptible to vortex induced motions in loop currents. The relatively large water plane area results in a decreased natural heave period, which locates the floater in the wave period range with more wave energy. Considering this, the hull design of Octabuoy semi-submersible has been optimized to improve the floater's motion performance. The optimization has been conducted with optimized parameters of the pontoon's rectangular cross section area, the cone shaped section's height and diameter. Through numerical evaluations of both the 1st-order and 2nd-order hydrodynamics, the optimization through genetic algorithms has been proven to provide improved hydrodynamic performance, in terms of heave and pitch motions. This work presents a meaningful framework as a reference in the process of floating system's design.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.118-126
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• 2024

In this paper, the research contents and results related to the automation of the hull-form optimal design of container ships are summarized. A container ship is a ship that generally operates near Froude number of 0.26. To implement hull-form optimal design automation for ships operating at this speed, an optimization algorithm, a hull-form change algorithm, a ship performance prediction algorithm, an automation algorithm, and an iterative calculation technique were applied to develop a numerical analysis computer program that enables hull-form optimal design automation of the container ship, and it was named HOTCONTAINER. In this study, a sensitivity analysis algorithm was developed and applied to appropriately set design variables for hull-form optimal design. To understand the reliability and real ship applicability of the developed algorithm, a numerical analysis was performed on KCS(KRISO Container Ship), a container ship that has been studied in various ways worldwide. Consequently, the optimal ship was derived, and the wave resistance, wave pattern, and wave height of the target and optimal ship were compared. In conclusion, compared the target ship, the optimal ship a 47.63% decrease in wave resistance, and the displacement and wet surface area decreased by 0.50% and 0.39%, respectively.

• Journal of Sensor Science and Technology
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• v.18 no.1
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• pp.22-27
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• 2009

The GPS(global positioning system) made up of 28 artificial satellites going round around the earth at a height of 20,000.Km is a system to determine the receiver's location by measuring the distance between the satellite and receivers using an electronic wave. Recently it's been widely used in various applications, such as a navigator, a surveying system, etc. In this paper, we propose a new algorithm to transform coordinates from GPS signals corresponding to various sizes of maps, and the application using this algorithm is also introduced. The algorithm is programmed by MFC on the WinCE 5.0 operating system, and the GPS receiver with a 20 channel high sensitivity and GPS microcontroller chip manufactured by SiRF Technology was used.