• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.233-243
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• 2014

The difference of mooring tension by type of buoy was investigated in the circulating water channel and the wave tank for deducting the most stable buoy from the current and the wave condition. 5 types of buoy made up of short cylinder laid vertically (CL-V), short cylinder laid horizontally (CL-H), capsule (CS), sphere (SP) and long cylinder (CL-L) were used for experiments. A mooring line and a weight were connected with each buoy. A tensile gauge was installed between a mooring line and a weight. All buoy's mooring tension was measured at the same time for the wave test with periods of 1.5~3.0 sec and wave heights of 0.1~0.3 m, and the current test with flow speeds of 0.2~1.0 m/sec. As a result, the order of tension value in the wave test was CL-H > CL-V > SP > CS > CL-L. In the current test CL-V and CL-H were recorded in the largest tension value, whereas SP has the smallest tension value. So it seems that SP buoy is the most effective in the location affected by fast current. CS is predicted to be suitable for a location that influence of wave is important more than that of current if practical use in the field is considered. And it was found that the difference of mooring tension among buoys in wave is related to the product of the cross sectional area and the drag coefficient for the buoy's bottom side in high wave height. The factor for the current condition was not found. But it was supposed to be related to complex factors like a dimension and a shape by buoy's posture to flow.

• Journal of Satellite, Information and Communications
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• v.11 no.2
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• pp.8-13
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• 2016

A buoy is a float attached by chain to the seabed to mark channels in a harbor or underwater hazards and can be classified into two major types as autonomous buoys and fixed buoys. When there is high demand such as marking channels in a harbor, monitoring ecology of ocean and environmental monitoring of coastal areas, smart buoys are developed. The smart buoys have wireless network systems such as GPS, CDMA and ZigBee. Using the GPS techniques, location and environments of buoy can be monitored and traced. However, the GPS in fixed buoy systems has a high power consumption and cost. Using many buoys on low power ZigBee basis allows dramatic reduction of the overall power consumption. In this study, it is aimed at the design of the trackable protocol for a buoy system which has low data rate and low power consumption. The proposed protocol has advantages that it can detect abnormal movement and gather trackable information without any system changes. In the introduced protocol, additional 2 bits and join request messages are used for trackable buoy system. The behaviors of improved protocol is modeled into petri-net and proved a reachability.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.497-502
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• 2013

There are currently 10 types of buoy, mostly which' design and development is dependent on foreign technology. In this study, it is aimed at the development of small instrumentation buoy and at the design proposal presented a numerically safety. The numerical method has the simulation of variety of marine environments, such as wave response amplitude ratio and each flux changes. Through the numerical simulation of buoy's kinetic movement, it is analyzed that Pitching motion increases by the frequency response of encounter and Added resistance appears to be the most significant on transverse waves. Finally, the proposed buoy is confirmed with the response' safety under simulation' conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05b
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• pp.1133-1138
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• 2001

The focus of this paper is on the numerical investigation of obliquely incident wane interactions with a system composed of full submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing. The fully submerged systems allow surface and bottom clearances to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of fille second kind) tat satisfy the Helmholz governing equation. Using this computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, clearances. spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters call, if it is properly tuned to the coming waves, have good performances ill reflecting the obliquely incident waves over a tilde range of wave frequency and headings.

• Journal of Navigation and Port Research
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• v.43 no.2
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• pp.93-100
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• 2019

In 2001, about 20 years after the introduction of the standard buoys, the natural environment and maritime traffic flow changes in the waters near Korea and the necessity of improvement of the AtoN (Aids to Navigation) maintenance was suggested. The IALA provides guidelines for maintenance and management of AtoN, and Korea provides guidelines for the management and operation of standard buoys by means of the Enforcement on the AtoN laws. The objective of this study was to investigate the installation status and the repair status of the standard type buoys by sea area in order to improve the management and operation of the steel standard buoys. In addition, a survey was conducted on the improvement of the steel buoy fouling and the improvement of the lifting inspection cycle towards on the AtoN managers and producers of the representative authority by sea area. In the case of LL-26 (M) buoy type, the standard type buoy installation status of Korea in 2017 was 57.1%, and the LL-26 (M) type was 58.9% showing the highest repair rate. According to the results of the survey on buoys fouling, 51.2% were caused by the attachment of shellfish, and 43.2% were caused by bird feces. The results of the survey on the improvement of the regular buoy inspection cycle showed that the measures are to maintain the current inspection period of 2 years regardless of the characteristics of the sea area (water depth, inside and outside port, buoy size, etc.).

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.11-21
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• 2001

The focus of this paper is on the numerical investigation of obliquely incident wav interactions with a system composed of fully submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing between two systems. The fully submerged two systems allow surface and bottom gaps to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of the second kind) that satisfy the Helmholz governing equation in fluid domains. A boundary element program for three fluid domains based on a discrete membrane dynamic model and simple source distribution method is developed. Using this developed computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, gaps, spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters can, if it is properly tuned to the coming waves, have good performances in reflecting the obliquely incident waves over a wide range of wave frequency and headings.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.313-320
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• 2022

The light buoy installed on the sea is always flexible, because it is affected by the weather as well as passing vessels. The position of the light buoy can be cached through the AtoN AIS (Automatic Identification System) and RTU (Remote Terminal Unit). This study analyzed the position data of the light buoys for the last five years (2017-2021), as well as the distribution of the light buoys within the maximum separated position. As a result, there was a basic error of 17.9% in the position data. Additionally, the separated position error of 197 light buoys to be analyzed was 70.64%, and the AtoN RTU was worse than the AtoN AIS by equipment. On the other hand, as a result of the plotting the position data of the light buoy, it was classified into four types. The most common percussion center type, the percussion center dichotomous type in which the position is divided into two zones based on the chimney, the central movement type with a fluctuating center, and the drag type, in which the position is deviated from the center for a certain period. Except for Type-1, the type was determined according to the position at which the light buoy was installed. This study is the first to analyze the position data of the light buoy, and it is expected that it will contribute to the improvement of the quality of the position data of the light buoy.

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.134-141
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• 2001

An experimental method to investigate the dynamic characteristics of buoys in extreme environmental condition is established. Because the buoy model requires a resonable size for accurate experiment, the test condition in model basin that satisfies the similarity law is hardly compatible with capability of test facilities. It is suggested that the linear wave component that is unable to satisfy similarity is separated with others. The model experiment is carried out with mitigated condition for the linear wave components while others including wave drift, current and wind are keeping the similarities. Then, the result can be extrapolated to give the dynamic behavior of buoys n extreme condition because linear wave component is solely responsibly to oscillatory buoy motion and other environmental components are applied as a initial tension. The similarity for current and wind conditions is viewed as equivalence of restoring forces. The validity of proposed method is examined with different types of standard ocean buoys and it indicates that the linearity of measured characteristics is assured with a limitation of resonable distance between test and estimated wave conditions.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.208-215
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• 2001

An experimental method to investigate the dynamic charasteristics of buoys in extreme environmental condition is established. Because the buoy model requires a resonable size for accurate experiment, the test condition in model basin that satisfies the similarity law is hardly met with capability of test facilities. It is suggested that the linear wave component that is unable to satisy similarity is separated with others. The model experiment can be carried out with mitigated condition for the linear wave components while others including wave drift, current and wind are keeping the similarities. Then the result is extrapolated to give the dynamic behavior of buoys in extreme condition because linear wave component is soley responsible to oscillatory buoy motion and other environmental components are applied as a initial tension. the similarity for current and wind conditions is viewed as equivalence of restoring forces. the validity of proposed method is examined with different types of standard ocean buoys and it indicates that the linearity of measured characteristics is assured with a limitation of resonable distance between test and estimated wave conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.72-74
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• 2022

Several types of data are collected from buoy due to the development of hardware technology.. However, the collected data are difficult to use due to errors including missing values and outliers depending on mechanical faults and meteorological environment. Therefore, in this study, linear interpolation is performed by adding the missing time data to enable machine learning to the insufficient meteorological data. After the linear interpolation, XGBoost and KNN-regressor, are used to forecast error data and suggested model is evaluated by using real-world data of a buoy.