• Journal of Power System Engineering
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• 제18권6호
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• pp.64-69
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• 2014

A circular plate is one of the important structures in many industrial fields. In static analysis of a circular plate, we may obtain an exact solution by analytical method, but it is limited to a simple circular plate. Thus, many researchers and designers have used numerical methods such as the finite element method. The authors of this paper developed the finite element-transfer stiffness coefficient method (FE-TSCM) for static and dynamic analyses of various structures. FE-TSCM is the combination of the modeling technique of the finite element method (FEM) and the transfer technique of the transfer stiffness coefficient method (TSCM). FE-TSCM has the advantages of both FEM and FE-TSCM. In this paper, the authors formulate the computational algorithm for the static analysis of axisymmetric circular plates under lateral loading using FE-TSCM. The computational results for three computational models obtained by FE-TSCM are compared with those obtained by FEM in order to confirm the accuracy of FE-TSCM.

• Journal of the Korean Society of Marine Environment & Safety
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• 제11권1호
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• pp.23-28
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• 2005

We have investigated the usefulness cf active stabilizing system to reduce ship rolling under disturbances, using varying reaction cf the flaps. In the proposed anti-rolling system for a ship, the flaps as the actuator are installed on the stem to reject rolling motion induced by disturbances like wave. The action induced by flaps which depends on power of disturbances am take the ship balance. Especially, in this study we identify the controlled system under the undefined system structure using spectral analysis and experimental studies. Based on these informations, we design the controller to evaluate the usefulness of the proposed system.

• Proceedings of KOSOMES biannual meeting
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• 해양환경안전학회 2005년도 춘계학술발표회
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• pp.155-159
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• 2005

Analysis target ship is not introduced yet in domestic as steel yacht that is getting into the spotlight by leisure life in Australia or Japan. Sailing yacht or Yacht for leisure time made of FRP into controlling power fare mainly and the design and made of latest fishing boat and something of domestic is consisting mainly. To need investigated for concept is various kinds overall strength as that use mainly steel wire material structurally of steel yacht by small crafts about Longi strength, Transe strength portion even of design safety factor at subject to do Rule's allowable stress enough stable structure accomplish. But it is assessment of part intensity that become refer to most in small size ship.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.689-691
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• 2010

This study is the visually identification lighting for easy to distinguish using colors LED on AtoN facility in harbor gate, which have realized a controller for certainly express the gate of harbor by red light and green light of both sides a harbor and for synchronization at a time of right and left or sequential the harbor guidance light through synchronizer or timer by GPS. There is expectation effect that is prevent a confusion about distinguish of facility by ship's operator and to beautify a night scene of harbor, which is expressed to identification lighting differ from great many lighting of harbor with variable color lighting the lighthouse body and vertical layer color lighting using LED. Especially the function of AtoN is displayed for harbor safety message by CW lighting, and this system is the power consumption greatly reduce by candle alternated high light LED.

• Journal of Power System Engineering
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• 제18권6호
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• pp.113-119
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• 2014

Due to the development of the petroleum refining technology and continuously increased demand from markets, a quantity of gasoline and diesel oil produced from a restricted quantity of crude oil has been increasing, and residual fuel to be used at marine diesel engines has been gradually becoming low quality. As a result, it was recently reported that trouble oils which cause abnormal combustion such as knocking with extreme noise and misfire from internal combustion engines were increasing throughout the world. In this study, an author investigated ignitability and combustion quality by using combustion analyzer with constant volume(FCA, Fuel Combustion Analyzer) and middle speed diesel engine about MDO(Marine Diesel Oil), HFO(Heavy Fuel Oil), LCO(Light Cycle Oil) and Blend-HFO which was blended LCO of 1000 liters with HFO of 600 liters. Moreover, for betterment of ignitability and combustion quality of injected fuels, multi-injection experiment was carried out in the diesel engine using Blend-HFO. According to the results of FCA analysis, ignitability and combustion quality was bad in the order of MDO

• Journal of Navigation and Port Research
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• 제33권9호
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• pp.635-644
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• 2009

The optimum design of power yacht belongs to the nonlinear constrained optimization problems. The determination of scantlings for the bow structure is a very important issue with in the whole structural design process. The derived design results are obtained by the use of real-coded micro-genetic algorithm including evaluation from Lloyd's Register small craft guideline, so that the nominal limiting stress requirement can be satisfied. In this study, the minimum volume design of bow structure on the power yacht was carried out based on the finite element analysis. The target model for optimum design and local structural analysis is the bow structure of a power yacht. The volume of bow structure and the main dimensions of structural members are chosen as an objective function and design variable, respectively. During optimization procedure, finite element analysis was performed to determine the constraint parameters at each iteration step of the optimization loop. optimization results were compared with a pre-existing design and it was possible to reduce approximately 19 percents of the total steel volume of bow structure from the previous design for the power yacht.

• Proceedings of the Korean Information Science Society Conference
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• 한국정보과학회 2008년도 한국컴퓨터종합학술대회논문집 Vol.35 No.1 (D)
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• pp.480-484
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• 2008

DNP3.0은 산업 분야에서 SCADA(Supervisory Control And Data Aquisition) system의 개방형 프로토콜로 사용되어지고 있다. 본 논문에서는 개발하거나 개발된 Module들 사이에서 송 수신되는 DNP3.0 PDU를 분석할 수 있는 기능을 제공하는 DPA(DNP3.0 Protocol Analyzer) Module을 설계 및 구현하였다. 해당 Master Station에서 Request 메시지를 생성하여 Outstation으로 전송하고 Outstation에서 수신된 Request 메시지를 분석하여 Response 메시지를 생성하여 Response 한다. 또한 Master Station 과 Outstation에서 DNP3.0 프로토콜을 사용하여 통신하는 중간에서 송 수신하는 메시지를 Monitoring한다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권7호
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• pp.713-721
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• 2005

A marine diesel engine should realize optimal operation efficiency while reducing NOx, PM (Particulate Matters) and other emissions. Fuel injection systems that use electronic control can become an effective means of achieving that objective. However. it still needs some accurate and instant information in order to bring its ability into full potential while sailing on the sea. The important information of them are a shaft torque and continuous combustion pressures of all cylinders. The shaft torque and the propeller thrust described in this paper are measured at an intermediate shaft by using a unique principle that one of two electromagnet coils oscillates a vibrating strip which the length changes with force and the other coil picks up the change of the frequency of the vibrating strip. For further reference, the shaft power meter multiplied the torque by the shaft revolution has already had about 750 sets of sales performance. The research presented in this paper started about ten years ago and is concerned with the development of a combustion pressure sensor that uses the same principle. Recently, the pressure sensor which bears continuous operation has been developed after a hard struggle, that is, the system that consists of a shaft horsepower meter, a propeller thrust meter and a combustion pressure sensor has been completed and has been shown to be reliable. This paper describes the configuration of this system, the material of the combustion pressure sensor, the principle of that, and the improving point of the sensor, and, we finally consider the use of this system.

• Journal of the Korean Society of Marine Environment & Safety
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• 제25권7호
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• pp.982-990
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• 2019

The interest of researchers and governments in exploiting tidal energy resources is increasing. Jangjuk strait is a place with high tidal energy density potential and is therefore appropriate for the constructing of a tidal turbine farm. In this study, a numerical approach is presented to evaluate the current flow and power potential in Jangjuk strait with an ADCIRC model. Then, the tidal field characteristics are utilized as input parameters for tidal resource calculation with an in-house program. The 1 MW scale tidal energy converter devices are employed and arranged in 4 layouts to investigate the annual energy yield as well as flow deficit due to the wake ef ect at the surveyed area. The best-performed array generates an annual energy yield up to 12.96 GWh/year (without considering the wake effect); this value is reduced by 0.16 GWh/year when accounting for the energy loss caused by the flow deficit. Moreover, by altering the turbine yaw angle during the flood and ebb tides, the impacts of this factor on the energy extraction are analyzed. This indicates that the turbine array attains the maximum tidal power when the turbine yaw angle is at 346° and 164° (clockwise, to the North) for the spring and neap tide in turns.

• Journal of information and communication convergence engineering
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• 제5권3호
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• pp.273-280
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• 2007

The numerical methods for finding the optimal parameters in 640 Gbps (16 channels $\times$ 40 Gbps) WDM system with optical phase conjugator (OPC) are proposed, which effectively compensate the distorted overall WDM channels. The considered optimal parameters are the OPC position and the dispersion coefficient of fibers. The numerical approaches are accomplished through two different procedures. One of these procedures is that the optimal OPC position is previously searched and then the optimal dispersion coefficient is searched at the obtained optimal OPC position. The other is the reverse of the above procedure. From the numerical results, it is confirmed that two optimal parameters depend on each other, but less related with the searching procedure. The methods proposed in this research will be expected to alternate with the method of making a symmetrical distribution of power and local dispersion in real optical link which is a serious problem of applying the OPC into multi-channels WDM system.