• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.2
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• pp.109-115
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• 2016

The trend in appearance of storm waves on the east coast of Korea was investigated based on long-term wave data observed at six different stations. At the four wave stations of KIOST (Sokcho, Mukho, Hupo, and Jinha), no notable trend was found during the observation period with respect to the annual average and maximum values of the significant wave height. In addition, the annual number of the appearance of storm waves showed decreasing trend at the three stations except Jinha, where slightly increasing trend of the quantity was recognized. In contrast, at Donghea ocean data buoy of KMA, abruptly increasing trend was found for the annual average and maximum of the significant wave height and for the annual number of the appearance of storm waves as well, demonstrating lack of consistency in the observation data from Donghea buoy of KMA.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.3
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• pp.111-118
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• 2004

An ocean buoy was deployed 10 km off Donghae city, Korea at a depth of 130 m to measure meteorological (air pressure, air temperature, wind speed, wind gust, wind direction, relative humidity) and oceanographic data (water properties and currents in the whole column) in real-time. The buoy recorded a maximum wind gust of 25 m/s (10 minutes' average speed of 20 m/s) and a minimum air pressure of 980 hPa when the eye of typhoon Maemi passed by near the Uljin city, Korea at 03:00 on 13 September 2003. The wave height reached maximum of 9 m with the significant wave height of 4 m at 04:00 (1 hour after the passage of Maemi). The currents measured near the surface reached up to about 100 cm/s at 13:00 (10 hours after the passage of Maemi). The mixed layer (high temperature and low salinity) thickness, which was accompanied by strong southward current, gradually increased from 20 m to 40 m during the 10 hours. A simple two layer model for the response to an impulsive alongshore wind over an uniformly sloping bottom developed by Csanady (1984) showed reasonable estimates of alongshore and offshore currents and interface displacement for the condition of typhoon Maemi at the buoy position (x=8.15 km) during the 10 hours.

• Journal of Environmental Science International
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• v.17 no.4
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• pp.461-468
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• 2008

Competitive power of pelagic fishery in Korea has been weakened by the domestic and international problems such as wage increase and exclusive economic zone. To make it worse, fishing fleet spends more than 80% of fishing time on searching fishing grounds. Real-time information on oceanographic data, temperature in particular, are likely to contribute to raise efficiency of fishing. However, available data obtained by satellite remote sensing, fixed buoy and drifting buoy, limited to sea surface or fixed positions. ARGO (Array for Real-time Geostrophic Oceanography), an international program, has delivered vertical profiles of temperature and salinity in the upper 2000m of the world ocean every 10 days using freely moving floats. We have developed real-time oceanographic information system for pelagic fishery based on the Argo data which has the contents of vertical profile, horizontal distribution and vertical section of temperature around fishing grounds and searched data can be download unrestrictedly. Comparison of skipjack catch with sea surface temperature and depth of $20^{\circ}C$ derived from Argo data in the West Equatorial Pacific revealed that Argo data are able to help fishing fleet to find fishing grounds and to increase catch.

• 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 Ocean Engineering and Technology
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• v.38 no.3
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• pp.103-114
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• 2024

Remote sensing wave observation data are crucial when analyzing ocean waves, the main external force of coastal disasters. Nevertheless, it has limitations in accuracy when used in low-wind environments. Therefore, this study collected the raw data from MIROS Wave and Current Radar (MWR) and wave radar at the Ieodo Ocean Research Station (IORS) and applied the optimal filter by combining filters provided by MIROS software. The data were validated by a comparison with South Jeju ocean buoy data. The results showed it maintained accuracy for significant wave height, but errors were observed in significant wave periods and extreme waves. Hence, this study used an artificial neural network (ANN) to improve these errors. The ANN was generalized by separating the data into training and test datasets through stratified sampling, and the optimal model structure was derived by adjusting the hyperparameters. The application of ANN effectively improved the accuracy in significant wave periods and high wave conditions. Consequently, this study reproduced past wave data by enhancing the reliability of the MWR, contributing to understanding wave generation and propagation in storm conditions, and improving the accuracy of wave prediction. On the other hand, errors persisted under high wave conditions because of wave shadow effects, necessitating more data collection and future research.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.600-613
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• 2015

The Fishing gear loss has been repeated every year in the West Sea; however, there has been no solution. So fisher men have undergone economic loss every year. Thus it is required to reduce the loss of fishing gear. In this study to find out the reason that the fishing gear is lost in the Sea, 10 years data of wave and current for 6 locations in the West Sea were investigated and a numerical modelling were conducted into the behaviour of a gillnet in wave and current. The fishing gear was modelled with the mass spring model. As a result, it came out into the open that the location where fishing gear loss occurred most frequently was Choongnam province. The height of the maximum significant wave in this province was 6.7 m and the period of that was 4.4 second. The maximum current speed was 0.7 m/s. As a result of simulation with these data, it was revealed that the buoy is one of the reasons to decrease the holding power of the gillnet. For example, the tension of anchor rope was decreased to 50% while the drag coefficient or volume of buoy was decreased to 25%. So it is predicted that an improvement of the buoy contributes to the reduction of the gillnet loss.

• Korean Journal of Remote Sensing
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• v.33 no.3
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• pp.275-285
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• 2017

National Meteorological Satellite Center(NMSC) has produced Sea Surface Temperature (SST) using Communication, Ocean, and Meteorological Satellite(COMS) data since April 2011. In this study, we have developed a new regional COMS SST algorithm optimized within the North-West Pacific Ocean area based on the Multi-Channel SST(MCSST) method and made a composite SST using polar orbit satellites as well as the COMS data. In order to retrieve the optimized SST at Northwest Pacific, we carried out a colocation process of COMS and in-situ buoy data to make coefficients of the MCSST algorithm through the new cloud masking including contaminant pixels and quality control processes of buoy data. And then, we have estimated the composite SST through the optimal interpolation method developed by National Institute of Meteorological Science(NIMS). We used four satellites SST data including COMS, NOAA-18/19(National Oceanic and Atmospheric Administration-18/19), and GCOM-W1(Global Change Observation Mission-Water 1). As a result, the root mean square error ofthe composite SST for the period of July 2012 to June 2013 was $0.95^{\circ}C$ in comparison with in-situ buoy data.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.2
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• pp.153-158
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• 2022

A telesounder is a device that can monitor the appearance of fish in the sea on land and store fish detection data. This study was conducted to monitor the appearance of fish resources in coastal or near seas by using LTE communication for data transmission of the telesounder. The purpose of this study was to develop a prototype telesounder that can monitor the appearance of fish groups in the waters about 50 km away from the coast and store fish detection data. In this study, the prototype telesounder including a fish finder, communication device and battery for stable operation at sea was developed. The stability of telesounder buoy, data transmission/reception and expected use time were investigated. The expected use time of the telesounder using LTE communication with a lithium battery (12 V, 120 Ah) was about 274 hours under the conditions of 10 minutes off and 10 minutes on, about 520 hours under the conditions of 30 minutes off and 10 minutes on, and about 142 hours under continuous conditions. As a result of the sea test, it was found that the telesounder can be used in the sea area moved about 34 km from the land and the telesounder buoy was evaluated to have secured basic stability (buoyancy balance, waterproof, antenna strength, etc.) for operation in a marine environment.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.158-165
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• 2020

Buoys are a necessary component for the safety of vessel traffic. However, if the buoy becomes inoperable from damage and loss, it can have significant impact on vessel traffic safety as well as unexpected budget spending. The purpose of this study was to evaluate the risk of accidental contact by applying the marine traffic assessment index that can reflect the traffic flow in the sea area. First, Busan Port No. 5 fairway, with a high number of buoys and many contact accidents, was set as the sea area for assessment. to investigate the status of accidental contact and evaluate risk of contact accidents based on the IALA Waterway Risk Assessment Programme (IWRAP MkII) and Potential Assessment of Risk Model (PARK Model). As a result, buoys are near the P recautionary Area wherein the traffic flow was complicated by the Masan port vessel and Busan new port vessel, and buoys are near the entrance of the Gadeok waterway, wherein vessels show a pattern of navigation across the fairway and buoys are near the breakwater in the inner fairway were considered as high risk for contact accidents. This study can be used as basic data for establishing an integrated model to evaluate the risk of buoy contact accidents.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.166-173
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• 2020

AtoN Accident causes navigation dangerous to ships and reduces the credibility of aids to navigation. The most light buoys on the sea have the highest accident rate from the influence of sea weather such as wind, current, and waves. However, in Korea, despite the different sea weather conditions in each sea area, in calculating the dynamic stability of the light buoy, there is a problem that only limit value conditions are applied to all sea areas. Thus, the purpose of this study was to analyze the dynamic stability of the LL-26(M) light buoy, the most installed buoy of its kind on the sea and suggest a stable operation plan for the LL-26(M) light buoy. To achieve this, after analyzing the weather for each sea area of the previous study related to the light buoy, the dynamic stability (inclination angle) was estimated by applying to the representative light buoys of each sea area wherein the number of accidents caused by sea weather was high. As a result of this study, the inclination angle of LL-26(M) light buoy for each sea area was different. That is, the inclination angle caused by winds was 10.329°-36.868°, the inclination angle caused by currents was 0.123°-18.834° and the inclination angle caused by waves was 4.777°-20.695°. The results of study can be used as basic data useful for installation standards for each sea area for stable operation of the LL-26(M) light buoy.