• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.574-584
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• 2017

In this paper, the optimizing path finding control method is studied for a Legged-robot. It's named TITAN-VIII. It has a lot of advantages over the wheeled robot in the ability to walk freely on an irregular ground. However, the moving speed on the ground of the Legged-robot is slower than the Wheeled-robot's. Consequently, the purpose of the method is presented in this paper to minimize its time when it walks to a goal. It find the path, our approach is based on an algorithm which is called Dijkstra's algorithm. In the rest of paper, the various posture of the robot is discussed to keep the robot always in the statically stable. Based on above works, the math formulas are presented to determine the joint angles of the robot. After that an algorithm is designed to find and keep robot on the desired trajectory. Experimental results of the proposed method are demonstrated in the last of paper.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.205-214
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• 2013

In Yeongsan River estuary, located in the southern West Coast, a dike was constructed in December 1981. After the construction of a dike, discharge mechanism of fresh water has been changed, the water quality and chlorophyll-a are expected to be influenced by fresh water discharge. We investigated temporal and spatial variations and long-term trend of phytoplankton biomass (chlorophyll-a) and environmental factors. The concentrations of nutrient and chlorophyll-a were generally high in summer and the concentrations were increased toward downstream. Surface/bottom salinity difference was negatively correlated with salinity in surface water but positively with nutrient and chlorophyll-a. TN, TP and DIN concentrations were generally increased over 10 years. This study can provide information for better management of water quality for Youngsan River estuary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.143-148
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• 2011

Daesan Harbor is developing under the Industrial Complex or Petrochemistry Development Plan making the port the main hub-port in the West coast. Because of this development. the traffic volume is expected to increase to 9,1.95 incoming vessels by 2020, an increase of 167% compared to 2008 figure. This study thoroughly analyzes and evaluates a systematic and comprehensive use of the fairway in the Daesan Harbor. It establishes a future oriented and safe marine transportation environment upon appropriate examination of the total fairways and sailing assistance facilities.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.2
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• pp.28-37
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• 2003

We investigated water quality, salinity, nutrients, SS, COD and Chlorophyll-a concentrations in the seawater of the Mokpo costal area, southwestern coast of Korea. Seawater samples at 25 stations were collected in July 20, 25 and September 3, 2002 after a strong rain event. The distributions nutrients in seawater were analyzed using an method of sea water analysis presented by the ministry of Maritime Affairs and Fisheries of Korea. The sampling sites were categorized into the inner and outer harbour based on salinity distribution and difference of nutrients distributions was evidence between these two zones. Nutrients and SS inflow and distributed in the inner harbour by the discharged freshwater from Youngsan river during strong rainfall whereas they were distributed in seawater of outer harbour by natural processes in general coastal area.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.431-436
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• 2003

It's about time we had to think an alternative to recover out insufficient fishery market caused by IMF locally as well as the fishery agreement on Japan and China. The Ministry of Maritime Affairs ＆ Fisheries have planning the advancing fishery information integrated system for the fishing present condition, marine resource administration and applicability consideration. The fishery information communication system is build up to the raw data ＆ process-network-content. The communication system must be small size, low cost and adapted SSB transceiver, that is using fishery shipping. In this paper We present digital data communication network to exchange information for fishery and safety between fishing ship and coast station in cheeper communication fee using SSB(single Side Band) in HF(High Frequency) band.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.566-573
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• 2021

In this study, safety management procedures were developed based on domestic and foreign guidelines and related maritime law to ensure the safe development and implementation of smart autonomous ship technology and Samsung Heavy Industry. The safety management procedure was developed according to the guidelines for (MASS) sea trials (MSC.1/Circ.1604, Annex: Interim guidelines for MASS trials), proposed by International Maritime Organization (IMO) for the relevant authorities and stakeholders of MASS to properly conduct tests of systems and infrastructure related to safety and environmental protection. The developed safety management procedure applies to the maritime demonstration test of a system applying autonomous navigation element technology mounted as a navigation aid on a ship operating under a watch system, while complying with the environmental protection and navigation safety of the coast of Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.135-145
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• 2024

At the 80th session of the MEPC, the IMO presented an enhanced GHG reduction strategy. The strategy is more specific and robust than the initial strategy presented at the 72nd session. The IMO aims to achieve 'Net Zero' GHG emissions from international shipping by 2050. In this study, a risk assessment was conducted for representative green fuels, namely. LNG, hydrogen, methanol, and ammonia. The fuzzy method was used to resolve the subjective ambiguity of results from the survey of the experts, and the positive and negative ef ects of the fuzziness were derived through the TOPSIS method. Finally, the closeness coefficients of the considered alternative fuels were determined using the Vertex method. As a result, methanol, LNG, hydrogen, and ammonia were preferred. This study suggests that the proposed approach can be used as a collective decision-making tool for selecting alternative fuels.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.373-380
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• 2017

Operational errors caused by human factors, which is the major cause of marine accidents, include lack of knowledge, misunderstanding knowledge, and inadequate procedures. Recently, the type of propulsion mounted on KCG cutters has been diversified. In particular, the water jet propulsion unit, which was mainly installed in small boats, have been gradually expanded to medium and large size Coast Guard cutters, reaching 50% of the total. Axes types are divided into 2 to 4, and the bucket types are divided into Double Reverse Bucket(DRB) and Single Reverse Bucket(SRB); in these, the backward and steering control methods are completely different. Diversification of these operating systems can increase factors causing human error by the ships' operators. However, there is a lack of research on the maneuvering methods, considering the inherent active characteristics of each type of water jet. In this paper, we analyze the sideway method suitable for the condition of Coast Guard Exclusive wharf without assistance, based on the astern performance of each type. Then, a ship handling simulator was used for the experiment; they compared and verified through interviews of captains.

• Journal of Korea Port Economic Association
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• v.36 no.4
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• pp.53-74
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• 2020

It is important to understand the current status and problems of the North Korean shipping industry to prepare for inter-Korean trade in the future era of peace in the Korean Peninsula. In this study, the status of vessels calling in North and South ports was analyzed by year, cargo type (vessel type), and North Korean port type using Port-MIS data. In particular, considering the three years (2006-2008) in which inter-Korean trade was the most active, the flow of maritime transport was analyzed by visualizing data on vessels' arrival and departure in the North and South ports. Findings revealed that sea transportation between Haeju-Incheon was the most frequent, while the Haeju-Mokpo and Nampo-Incheon routes in the west coast area, and the Najin-Busan route in the east coast area were active. With reference to general cargo vessels, ports located on the west coast of Korea tended to operate between those located on the North coast of North Korea and on the east coast of South Korea. These results are expected to serve as a basis for establishing research and policies related to coastal shipping between the two Koreas in the future.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.133-141
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• 2007

There are produced more than 600,000 tons of seaweeds every year along the coast of the Korea. Jeonnam province, south-west coast area, of Korea is producing 93% of total amounts of seaweeds. The laver, sea mustard, and tangleweed maintain stability in the output and has been exported as a simple product processing through drying or salting. It was evaluated the low value-added products and limited the expansion for the consumption of seaweeds. The seaweeds contains 40-60% carbohydrate and structurally different compared with land plant. The dietary fiber from seaweeds has been known the function of facilitating the bowl movement, excretion the heavy metal in the body, lowering the blood cholesterol level, anti-coagulant of blood, and anticancer. Especially, brown algae including sea mustard, seaweed fusiforme, and tangleweed contains alginic acid, laminarin, mannitol, fucoidan which are lowering the blood cholesterol level, lowering blood pressure, and fusion of blood clot. Agar-agar, carrageenan, and porphyran compound in red algae are known to antimutagenicity and anticoagulant function. In spite of potential of seaweed as a main bio-resource, there are lack of research to facilitate the consumption with its functional properties and consumers are unsatisfied with simple processing products. Also, the seaweed by-product dump into the sea and cause pollution of the seawater. Therefore, there are needed the scheme to promote the consumption of seaweeds. The development of value-added products, finding functional properties from seaweeds, development the functional feed for animal using seaweed by-products, and utilization of unused algae for food or other industrial uses will increase fisherman's income as well as serve as an aid for the people health due to its functional properties. Using by-product of seaweed and unexploited seaweed are needed to development of bio-degradable food packaging material and functional feed for animal.