• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.549-556
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• 2011

In this paper, high performance radio buoy system for inshore and deep sea fishery is proposed and implemented. Binary FSK modulation technique is used for real-time communication & control between buoys and buoy finder, and optimum access protocol is adopted for minimizing the power consumption of radio buoy system. Using the GPS and sensor techniques, location and environments of radio buoy can be accurately monitored and traced by the mother ship. Developed buoy system with 10 W transmitting power can cover over 120km coastal range and operate more than 73 days of battery life. Proposed digital coding methods can also assure high security from burglary and loss.

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.191-198
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• 2015

In this study, we proposed a new type of dual-buoy wave energy converter (WEC) exploiting multi-resonance and analyzed the experimental results from a model test in a 2-D wave flume. A dual-buoy WEC using multi-resonance has two advantages: high efficiency at the resonant frequencies and the potential to extend the frequency range available to extract wave power from the WEC. The suggested WEC was composed of an outer buoy and an inner buoy sliding vertically inside the outer buoy. As the power take-off device, a linear electric generator (LEG) consisting of permanent magnets and coils fixed at each buoy was adopted. Electricity was produced by the relative heave motion between the two buoys. To search for the optimal shape of a dual-buoy WEC, we conducted experiments on the heave motion of a two-body system in regular waves without an LEG installed. Model tests with six combinations of experimental models were conducted in order to find the motion characteristics of a dual-buoy WEC. It was found that model 2, which included a ring-shaped appendage to move the resonant frequency of the outer buoy toward a high value, showed a higher relative heave response amplitude operator (RAO) curve than model 1. In addition, the double-peak shape of the heave RAO curve shown for model 2 indicated the extension of the frequency range for extracting wave power in irregular waves.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.553-555
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• 2004

In this paper, high performance radio buoy system used for inshore and deep sea fishery is developed and experimented. Location of radio buoy can be accurately monitored and traced by the mother ship using GPS technology, and optimum access protocol is adopted to minimize the power consumption of radio buoy system. Developed system can cover over 80Km coastal range with 8 W transmitting power and -115 dBm receiver sensitivity and can ensure high security from burglary and loss using digital coding technology.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.550-552
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• 2004

In this paper, access protocol is proposed that can optimally control the radio buoy system used for inshore and deep sea fishery. Proposed protocol can minimize the power consumption of radio buoy and can ensure high security from burglary and loss, and it enable a mother ship to control remotely more than 150 radio buoys simultaneously. GPS technology and remote control techniques are used to monitor the exact location and status of the radio buoy system in real time.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.35-39
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• 2010

This research is part of the development of buoy system specially designed for meteorology and oceanographic purposes. The control system design and the brief operation of the buoy will be discussed in this paper.

• Ocean and Polar Research
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• v.33 no.spc3
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• pp.359-369
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• 2011

This study documents KORDI's experience of successfully deploying a deep ocean buoy for monitoring oceanic and atmospheric variabilities in the tropical western Pacific Ocea nsince May 2010. The primary focus of this study was to compare TRITON (big and old type) with m-TRITON (smaller and new type) buoys within the JAMSTEC's buoy management system. The objective of operating a KORDI buoy is to ascertain oceanic variability in the tropical western Pacific. We adopted a slack-line mooring type to observe water temperatures at six layers from surface to 400 m depth. However, we could not acquire satisfactory results due to lack of expertise in buoy management system. A new KORDI buoy has been developing, which has been modified from both buoys, and ARGOS-3 satellite system and a slack-type mooring line.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.17-23
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• 2016

This study investigates the development of an automatic lightening buoy that can indicate an aquaculture cage at night or in rough weather. The energy for the light is generated by the linear motion of a magnet along with a coil inside the buoy as the waves cause the buoy to oscillate up and down. The principle of the magnet motion is different between the magnet and body of the buoy because the movement of the latter is dependent on the surface wave, while the former is affected by the damper. To obtain a quantitative performance of the buoy, the voltage as well as up and down motion produced by several waves were measured in the wave tank. A shorter wave period, i.e., faster motion, of the magnet produced a brighter light. It is expected that this study can aid in deciding the optimum design of a buoy capable of producing a bright light at any aquaculture site affected by sea or fresh water waves.

• Journal of Ocean Engineering and Technology
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• v.34 no.2
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• pp.66-76
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• 2020

A light buoy is equipped with lighting functions and navigation signs. Its shape and colors indicate the route to vessels sailing nearby in the daytime, with its lights providing this information at night. It also plays a role in notifying the presence of obstacles such as reefs and shallows. When a light buoy operates in the ocean, the visibility and angle of light from the lantern installed on the buoy changes, which may cause them to function improperly. Therefore, it is necessary for the buoy to have stable and minimal motions under given environmental conditions, mainly waves. In this study, motion analyses for a newly developed lightweight light-buoy in waves were performed to predict the motion performance and determine the effect of the developed appendages for improving the motion performance. First, free decay tests, including benchmark cases, were performed using computational fluid dynamics (CFD) to estimate the viscous damping coefficients, which could not be obtained using potential-based simulations. A comparison was made of the results from potential-based simulations with and without considering viscous damping coefficients, which were estimated using CFD. It was confirmed that the pitch and heave motions of the buoy became smaller when the developed appendages were adopted.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.86-101
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• 2021

This study examined the effects of buoy shape and Nonlinear Froude-Krylov force (NFK) on a heaving-buoy-type Wave Energy Converter (WEC). Based on the Maclaurin expansion, the theoretical solutions of the NFK were derived for three different buoy shapes; hemispheric buoy, circular vertical cylinder, and truncated conical cylinder. A hydraulic power take-off system was adopted, and the latching control strategy was applied to maximize the extracted power from the WEC. The nonlinear effects of the Froude-Krylov force and restoring force on the heaving point absorber were investigated by comparing the heave Response Amplitude Operator (RAO) and time-averaged power extraction. The results showed that the conventional linear analyses were overestimated by up to 50% under the high amplitude wave condition. The latching control strategy was the most effective when peak wave period of regular or irregular wave was 0.4-0.45 times the heave natural period of the buoy.

• 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.