• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.4 s.111
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• pp.33-44
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• 2005

In order to reveal the geographical landscape's features of the East Sea-gateway(東海口), which has existed only in the era of Shilla as unique east path, we have carried out analysis of the old maps(邑誌圖) and satellite imagery, and geographical features analysis in the application of digital maps, and the result is as follows. 1. Analysis of materials from the Chosun dynasty describes landscapes called sea gates(海口) (note that this should not be capitalized); a place where the river meets the sea and the sea comes far into the land. Sea gate landscapes may have an island, but this is not a prerequisite. 2. According to the satellite imagery, the capital city of Shilla Dynasty had five passages. four or them are broad corridors, but one of them is narrow. The east side of the capital city is blocked by mountains and there was an important path which leads into the East Sea. 3. According to the cross section of the mountains, there is the only rule East-path. There was no alternative way. There was only one way-out to the east side from the capital city. This is the unique path which reaches a length of 28km. Judging from this, it seems that this path was called the East Sea-gateway. 4. The landscape of the East Sea-gateway was shaped like the letter 'V' and reached to the landscape of the sea gate. However, the route was blocked - part by the mountains, and also the part in the crisis of loss of path-landscape which has lost its own character of closure as several valleys are merged together.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.735-739
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• 2010

This study investigated a method for monitoring fishes immigrating to upper streams from the sea in relation to water level with elapsed time, and measured fish behavior patterns and swimming speed in a fishing boat gateway using an acoustic camera system. This method was employed due to difficulties, linked to high turbidity, of using only underwater optical systems for monitoring fish migrating to brackish water. Results showed that fish length distribution showed high correlation between haul sampling and an automatic counting algorithm supported by the DIDSON software program. These results will help to maximize the effects of fish run management by increasing understanding of the amount of major fish species migrating in relation to durable water levels.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.278-287
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• 2011

NMEA 2000 protocol known as IEC 61162-3 of Multi-talker, Multi-listener and Plug and Play network communication has been adopted as standard network for SOLAS(Safety of Life at Sea) ship by IMO. This paper focuses on the implementation of FPGA and MicroBlaze for NMEA 2000 based gateway, which is able to convert NMEA 2000 protocol into various types of network protocol such as Ethernet, UART and USB using Vertex4-based ML401 board. Each communication module and the stack of NMEA 2000 are mounted on FPGA. To be able to receive each communication data, ML401 board is configured to handle required communication speed. PC based NMEA 2000 monitoring program is developed to verify that data on different networks are correctly converted each other in real time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.5
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• pp.779-786
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• 2018

Ministry of oceans and Fisheries declared action plan for the electric fishing gear using real name in order to prevent overusing the fishing gear and to reduce discarded fishing gear. It is needed for a technique that can efficiently transmit the information including the type and location of the fishing gear and the user's real name to the fishing boat and the control center using IoT-based communication. In this paper, we propose the buoy-launched terminal equipment and ship-launched gateway equipment based on LoRa technology for effectively executing the electric fishing gear using real name. We design and fabricate to communicate 1(gateway):200(buoy) each other under 900 MHz ISM band by using SEMTECH SX1276 chip. Also, we experiment the test on the sea and analyze the test results to prove the implementation possibility of the proposed equipments for the electric fishing gear using real name.

• The Journal of shipping and logistics
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• v.34 no.4
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• pp.527-544
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• 2018

In this study, SNA analysis was conducted to examine changes in passenger movements in domestic coastal shipping. The validity of derivation of centrality rankings was enhanced by using the connection centrality that reflected weights, which had not been applied in previous research. The results of the connection centrality analysis indicated that the network composition ratio of the South Sea region was high, and the results of analysis of betweenness centrality indicated that ports belonging to the South Sea region recorded high ranks. Jeju Island, which acts as a gateway to the West Sea and the South Sea, Mokpo, which acts as a gateway between the land and islands, those ports that are geographically close to the land, and those ports that are smoothly connected to small ports, were shown to have betweenness centrality. Meanwhile, in the results of analysis of eigenvector centrality, not only ports in the South Sea region but also many ports in the West Sea region were included in the high ranked ones. Using these results, the port authority can identify major ports in domestic coastal shipping, determine the priorities support, identify the current situation of the port connection relations, and establish strategies for management of key development areas. As future studies, studies in the aspect of economy that separate general passengers and island passengers and utilize data such as fares, distances, and time are necessary.

• Journal of IKEEE
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• v.24 no.4
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• pp.1069-1073
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• 2020

This paper presents the performance analysis of a long-range marine communication system developed for monitoring the fishing gears. LoRa based buoys were developed to monitor fishing gears. The buoy sends its coordinates along with other relevant information to the central monitoring station via a gateway. During the experiment, a up to 30 km of communication between a buoy and a gateway was successfully tested.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.9
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• pp.247-260
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• 2016

Sensor networks have been used in many applications such as smart home, smart factory, etc. based on sensor data. Sensor networks can change system requirements and architectures depending on their application areas. Currently, sensor network application cases in ocean environments are very rare because the ocean environments have much difficult accessibility more poor conditions, higher wave heights, more frogs, much heavier salinity, etc., compared with ground environments. In this paper, we propose the requirements, architecture and design of a sensor network system for the littoral sea cage culture monitoring and we also introduce its operation results through the development. The developed system based on our research provides users with functionalities to extract, monitor, and manage underwater environmental conditions suitable to littoral sea cage culturing of fishes.

• ALGAE
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• v.27 no.4
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• pp.269-281
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• 2012

Marado is a small rocky island located off the south coast of Jeju Island and acts as the first gateway of the Kuroshio Current to Korean coastal ecosystems. This island is one of the most unpolluted and well preserved sea areas around the Jeju coast. We extensively observed macroalgal assemblages of species and functional forms in the intertidal and subtidal zones through four seasons on Marado, Jeju Island, Korea to demonstrate the seasonality of vertical distribution patterns and biomass. A total of 144 species (14 Chlorophyta, 40 Phaeophyta, and 90 Rhodophyta) were identified in quadrats and were analyzed seasonally and vertically to define the variation patterns. The annual mean biomass of macroalgae was $2,932.3g\;wet\;wt\;m^{-2}$ and the highest value was recorded in spring and the lowest was in winter. The annual dominant species by biomass was Ecklonia cava followed by Sargassum fusiforme, S. macrocarpum, Amphiroa galapagensis, Chondria crassicaulis, and S. thunbergii. Obvious biomass zonation patterns of macroalgal species were detected in relation to tidal height and depth. Macroalgal biomass, diversity index (H'), and community dynamics were the highest in the shallow subtidal zone. Species number was higher in the subtidal than in the intertidal zone and similar throughout the entire subtidal zone. Our results provide revealing insights into the distribution patterns of macroalgal assemblages in an unpolluted sea area around Jeju Island.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.61-66
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• 2020

Since the ocean accounts for 70.8 percent of the earth's surface, the success of IoT technology in the marine industry is to collect information from devices placed in a wider range. LPWA is a feature with a wide range of communication and is very suitable for deployment in the ocean. In this paper, the real-sea performance distance experiment was carried out based on Private LoRa, a key technology for executing the electronic phrase real-name system. A private LoRa module based on sx1276 was developed, and Gateway was developed to transfer data received by private LoRa to the server using SKT Cat. M1. After installing gateways at 599 meters above sea level and experimenting with data transmission and reception at 25 km, 40 km and 60 km, we were able to see that the communication success rate was obtained to be 96.1%. 97.1% and 96.2% respectively.