• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.151-151
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• 2017

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.2
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• pp.104-110
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• 2006

The 3D visualization of seafloor topography(ST) was realized to discuss the effective use by the 3D visualization of ST on the integrated navigation system(INS) for fishing boat. The software was to actually display the 3D visualization of ST using triangular irregular network, helical hyperspatial codes and stereo projection. The INS for fishing boat which applied the 3D visualization of ST will be utilized for safety voyage and the effective fishing work on the fishing ground.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.414-420
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• 1997

An intelligent speed control system for marine diesel engines is presented. The approach adopt¬ed is to use a conventional PID controller for normal operation and a feedforward controller for adaptive control. The feedforward controller is a neural network. The neural network is the inverse dynamics model of the plant, which is being trained on line. The parametric model of the diesel engine is represented in a linear second-order system, with a first-order combustion part and a revolution part each at a normal operating point. The time delay in the control of the com¬bustion part is approximated to the first-order system. The tuned PID parameters are set based on the model for normal operating point. To obtain the inverse dynamics of the diesel engine system, two neural networks are used, one for inverse, the other for forward dynamics. The former is posi¬tioned across the plant to learn its inverse dynamics during operation, and the latter is placed in series with the controlled plant. Simulation results are presented to illustrate the applicability of the proposed scheme to intelligent adaptive control of diesel engines.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.149-153
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• 2005

Marine Propulsion shafting system coupled with medium diesel engine forms multi-degree torsional vibration system which consist of many inertia masses such as crank, flywheel, propeller and sometimes gear system is adopted additionally for the purpose of improving propeller's propulsion efficiency or connecting with PTO/PTI. The periodic excitation torques generated by combustion pressure in cylinder and reciprocating masses induce various kinds of vibrations in this shafting system. If the frequency of this excitation torques is equal to the natural frequency of the shafting, the amplitude of the torsional vibration increases steeply and the damage of crankshaft or gears may be occurred by that. This frequency is called critical speed. When making a plan for shafting system, it is important for this frequency to be expected exactly and not to be in commonly used speed. For this reason, this paper introduces the experimental equipment for torsional vibration of marine propulsion shafting system and describes the theoretic and the experimental methods to look for natural frequencies.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.568-573
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• 2009

Marine accidents have always caused huge economic losses, as well as environmental pollution. Prevention of marine accidents has become a focus of argumentation. The analysis of past accident cases, reviewing the experience and lessons, is important and necessary for preventing marine accidents. With the same subject above, the Korean Maritime Safety Tribunal provides for past marine accidents' written judgments and analysis of judgment and associated retrieval system on its homepage. In these systems, the name of the ship, accident occurrence time, accident pattern or related keywords are used as search conditions. However, most of the marine events' happening were not due to a single reason, but multiple ones. In addition, one marine event could often come under several categories. In this case, now the retrieval systems' DB is used on the Korean Maritime Safety Tribunal homepage was built based on single category and failed to be able to retrieve according to multiple reasons or multiple categories. In order to solve this problem, a more practical retrieval approach might be needed. Therefore, in this paper, a new retrieval system will be proposed, which using the linguistic label to describe the cluster after analyzing the relational properties between marine accidents and clustering by FCM algorithm, and then adding an interface to allow users to get the results they want through choosing multiple reasons or multiple categories.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.1
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• pp.7-19
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• 2019

This study was conducted in order to improve opening efficiency of the miniaturized small-scale net for anchovy boat seine gear to reduce the fleet size. Field experiment was performed to observe geometry of nets by catcher boats. When the distance between the two ships was 150, 300 and 450 m and the speed of towing nets was 0.6, 0.9, and 1.2 kt, the vertical opening and actual opening of each part of the miniaturized small-scale net was as follows: the front part of the wing net, 6.8-9.5 m, 45-63%; the middle part of the wing net, 16.1-30.7 m, 34-65%; the entrance of the inside wing net, 21.6-41.2 m, 44-84%; the square and bosom, 17.4-34.0 m, 38-75%; the entrance of the body net, 16.5-29.4 m, 36-64%; the entrance of the bag net, 14.5-21.9 m, 70-106%; the flapper, 6.7-7.7 m, 81-83%, and the end of the bag net, 8.6-10.9 m, 64-81%. The tension of towing nets was measured to be 2,734-6,812 kg approximately, which indicates that the fleet can tow nets with 350 hp, the standard engine horse power. The fishing operation time was shortened comparing to existent net with the large-scale buoy attachment operation. It was also possible to operate the ship without fish detecting boat.

• Corrosion Science and Technology
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• v.10 no.3
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• pp.101-107
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• 2011

Marine ships have played an important role as a carrier, transporting much more than 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. However, those marine ships have the characteristics such as voyage of long distance, large-volume and lower speed than the other carry system. Therefore, it is important to manufacture a larger and faster ship, however, the steel plates which are consisted with most of those ships has brought about many corrosion problems in sea water such as general corrosion, localized corrosion, cavitation and erosion corrosion etc.. Most hulls of the ships have been protected with paintings, sacrificial anode, marine growth prevention system, and impressed current cathodic protection methods against numerious corrosion problems mentioned above. However, these conventional methods are not very effective because the rudder of ships stern are exposed to very severe corrosive environment such as tides, speeds of ships, cavitations and erosion corrosion, etc.. In this study, electrochemical and cavitation characteristics was investigated for the rudder material of ship which is exposed to serious corrosive environment. As a result, it is considered that the optimum cathodic protection potentials of rudder material is the range of -0.6 V ~ -0.8 V(Ag/AgCl) in static seawater.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.1 s.139
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• pp.57-63
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• 2005

This paper introduces basic research of optimum routing assessment system as voyage support purpose which can obtain safe and efficient route. In view point of safety, the prediction of ship motion should be evaluated in the condition of rough weather This part includes general seakeeping estimation based on 3 dimensional panel method and parametric roil prediction. For increasing voyage efficiency, ETA(Estimated Time of Arrival) and fuel consumption should be calculated considering speed reduction and power increase due to wave effects based on added resistance calculation and ship performance characteristics. Basically, the weather forecast is assumed to be prepared previously to operate this system. The idea of these factors in this system will be helpful to escape from dangerous voyage situation by wave conditions and to make optimum route planning based on ETA and fuel consumption.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.472-475
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• 2005

This paper present a robot controller developed for shipbuilding yard. Since shipbuilding process handles large work pieces and has dusty and noisy environment, the developed controller has separated architecture into main control part and servo control part. Main control part is located in control room while servo control part is located near robot with work pieces. Commutation between two parts is done through SynqNet and RS485. Air purging system is adapted to servo control part for better reliability. We aimed open architecture in both hardware and software architecture. For open hardware architecture, we employed Compact PCI (cPCI) because it is widely used bus system and very reliable. Since lots of commercial boards are available with cPCI interface, upgrade and reconfiguration is easy. For open software architecture, Windows XP�� Embedded is selected as operating system (OS), because it is very popular OS and most hardware vender supports device driver for the windows XP.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.7
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• pp.994-1002
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• 2009

In this paper, effect of air gap thickness between absorber plate and glass cover on top heat loss of a closed loop oscillating heat pipe (CLOHP) solar collector was investigated. The CLOHP, which is made of copper with outer diameter of 3.2mm and inner diameter of 2.0mm, comprises 8 turns with heating, adiabatic and cooling section. The heating section of the heat pipe was attached to absorber plate which heated by solar simulator simulated by halogen lamps. The cooling section of the heat pipe was inserted into collector's cooling section that made of transparent acrylic. Temperatures of absorber plate, glass cover, and ambient air measured by K-type thermocouple and were recorded by MV2000-Yokogawa recorder. Top heat loss coefficients and top heat loss of the collector corresponding to some cases of air gap thickness were determined. The result of experiment shows the optimal air gap thickness for minimum top heat loss of this solar collector.