• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1305-1312
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• 2006

This study is about the development of measurement system using ubiquitous wireless communication for river flow monitoring. The system can acquire water depth, quality (temperature, pH, conductivity, turbidity etc.) while a GPS module for getting the location data of measurement points. Also this system is able to acquire the field data via RF connection and can be controlled same time. The acquired data is transmitted to a gateway system from the remote buoy using Zigbee wireless connection. And the gateway system is able to monitor the data through GIS monitoring tool. Finally the data are transmitted to a server computer using CDMA wireless connection by gateway system. The D/B of server computer are constructed automatically and monitored the project web site. The resulting system can be used for scour monitoring, environment monitoring and the other monitoring purposes such as a river flow monitoring system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1200-1207
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• 2015

A gateway buoy system connects a underwater network to a terrestrial network, which enables to efficiently monitor the underwater network on a land station. In this paper, we introduce an implemented gateway buoy system which relays gathered data from multiple underwater nodes to a land station in a real time. The gateway buoy hardware system is composed of a underwater acoustic modem system, a radio frequency modem system, and a gateway operating system. in additional, we have implemented a land operating program and a land monitoring program for gateway system and states of underwater network, respectively. We also perform real-sea experiments to verify the performance of the gateway buoy system which real-time monitors underwater network states and gateway system states.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.9
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• pp.1228-1236
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• 2018

Recently, the maritime environment contaminated by the abandoned fishing gears. To solve this problem, there requires systematic management techniques for the fishing gears based on ICT technologies. The existed systems are optionally used by owners, but the systems need to adopt the monitoring and control architecture for integrated national surveillance. To do this, we designed an architecture for effective monitoring and management which collects position and state information using automatic identification buoy (AIB) device, to send the fishing ship, administrator ship, and shore side control center based on the IoT networks. Especially, in this paper, we developed the ENC-based integrated control system for efficient management which provides functions for position indication, state information display and loss alarm of fishing gears. Also, we conduct performance tests for data processing and visualization functions of the system to use a virtual buoy generation module.

• Journal of Navigation and Port Research
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• v.45 no.4
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• pp.181-185
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• 2021

This study deals with the development of a phrase buoy control system that can receive and analyze phrase information using an IoT-based communication network to determine whether a phrase is normal or missing, to manage the current state of the phrase, check the status of the phrase in case of abnormal conditions in the phrase, and conduct management of the phrase. The fishing gear management system and integrated control structure design using an IoT-based communication network were developed, and a system test and verification were carried out to verify the effectiveness of the system.

• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.397-402
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• 2021

The real-name electric fishing gear system is one of the important policy capable to build 'abundant fishing ground' and to protect marine environment. And, fishing gear automatic-identification system is one of IoT services that can implement above-mentioned policy by using communication such as low power wide area (LPWA) and multi-sensing techniques. Fishing gear automatic -identification system can gather the location data and lost/hold data from electric buoy floated in sea and can provide them to fishermen and monitoring center in land. We have developed the communication modules and electric buoy consisted of fishing gear automatic-identification system. In this paper, we report the test results of communication distance between electric buoy and wireless node installed in fish boat and location error of electric buoy. It is confirmed that line of sight (LOS) distance between electric buoy and wireless node is obtained to be 62 km, which is two times of the desired value, and location error is obtained to be CEP 1 m, which is smaller than the desired value of CEP 5 m. Therefore, it is expected that service area and accuracy of the developed fishing gear automatic-identification system is more extended.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.3
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• pp.171-180
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• 2010

Analysis on the temporal variation of the stratification is carried out by using the continuous water temperature and salinity data observed in the coastal monitoring buoy in Mikawa Bay, Japan. The main analysis results are as follows. The stratification pattern have an obvious and dominant 1-year period variation and the occurrence frequency (days) are exponentially decreased as the stratification intensity (SI) defined as the density difference between surface and bottom layers linearly increases. The frequency distribution function of the SI is presumably close to the log-normal function type or exponential function type. From the water temperature and salinity scatter diagram analysis, the line and loop type patterns are shown in the bottom and surface layers, respectively. In addition, the analysis of the SI estimation show that the error bound in case of using the weekly-monitoring data is about 4.45 times greater than that in case of using the continuous (daily) monitoring data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.333-344
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• 2021

Technique for the long-gap filling that occur frequently in ocean monitoring data is developed. The method estimates the unknown values of the long-gap by the summation of the estimated trend and selected residual components of the given missing intervals. The method was used to impute the data of the long-term missing interval of about 1 month, such as temperature and water temperature of the Ulleungdo ocean buoy data. The imputed data showed differences depending on the monitoring parameters, but it was found that the variation pattern was appropriately reproduced. Although this method causes bias and variance errors due to trend and residual components estimation, it was found that the bias error of statistical measure estimation due to long-term missing is greatly reduced. The mean, and the 90% confidence intervals of the gap-filling model's RMS errors are 0.93 and 0.35~1.95, respectively.

• Journal of IKEEE
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• v.27 no.3
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• pp.225-233
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• 2023

This paper implements a system that monitors human body lifting information in the event of a marine accident. The monitoring system performs ultrasonic communication through a lifting device controller that transmits underwater environment information, and LoRa communication is performed on the water to provide GPS information within 10 km to the control center or mother ship. The underwater lifting controller transmits pneumatic sensor, gyro sensor, and temperature sensor information. In an environment where the underwater conditions increase by one atmosphere of water pressure every 10m in depth, and the amount of air in the instrument decreases by half compared to land, a model of a 60kg underwater mannequin is used. Using one 38g CO2 cartridge in the lifting appliance SMB(Surface Maker Buoy), carry out a lifting appliance discharge test based on the water level rise conditions within 10 sec. Underwater communication constitutes a data transmission environment using a 2,400-bps ultrasonic sensor from a depth of 40m to 100m. The monitoring signal aims to ensure the safety and safe human structure of the salvage worker by providing water depth, water temperature, and directional angle to rescue workers on the surface of the water.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.593-600
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• 2020

The equipment for marine IoT service have to overcome the effect of seawater. Furthermore, the free floating transmitter in seawater will be less affected by the seawater environment. The results of the design and fabrication of antenna, which is embedded in buoy, are shown in this research. The proposed antenna is used to supervise the states of fishing gears in monitoring system for real-name system of electric fishing gear. The selected frequency band of the proposed antenna is 920 MHz, and PCB pattern type is selected for subminiature and light weight. It is confirmed that RF characteristics is more degraded, however, the radiation is gradually upward as the contact surface of buoy with seawater is more broaden through the simulation results. That is, the RF performance of the proposed antenna is more deteriorated but beam radiation characteristics is more suited the marine IoT, the seawater effect is more increased. It is expected that the proposed antenna will contribute the implementation of IoT network based on low power wide area (LPWA) when the degradation of RF performance will be settled.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.7
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• pp.1021-1029
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• 2018

The marine buoys are operated in various domains, which are navigation route and danger maker, weather and environment monitoring, military strategical element, etc. If the marine buoy is damaged, there consumes many cost and time for recovery or replacement, because of severe environmental condition, and causes a risk possibility of secondary accident. In this paper, we developed an active monitoring and approach alarm providing system using trail cameras and AIS for protection for the marine buoys. To do this, we analyzed existing researches and similar systems, extracted requirements for enhancement, and designed the system architecture that applied the enhanced elements. The main considerations of system enhancement are: integration of AIS and trail cameras, adopting of phased alarm technique by approaching ships, applying of selective communication module, conducting the image processing of ships for providing alarm, and applying thermal cameras. After that, we developed the system using designed architecture and verified effectiveness of the system based on laboratory or field-level tests.