• Journal of Navigation and Port Research
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• v.28 no.2
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• pp.135-140
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• 2004

A purpose of developing a sound source tracking system in this paper is to reduce the noise efficiently from the received signal by microphone array and measure the signal's time delay between the microphones. I have applied the wavelet analysis algorithm to the system and calculated the sound source's relative position For the performance evaluation, I have compared with the results of utilizing the digital filtering methods based on the FIR LPF using Kaiser window function and the inverse Chebyshev IIR LPF. As a result, I have confirmed the fact that 'time-scale' filter using inverse discrete wavelet transform was suitable for this system.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.723-733
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• 2011

On the general fishing boat in the same person of the fishing Chief and the Captain, the fishing chief positions are not separately. In this case, in Civil, Criminal and Administrative law, does not cause any problems. Just he take only responsibility for the legal effect of each, this is a natural solution for the effects of laws. But, if make one work unit, the fishing chief take fishing work from the position of the dominant of the captain, and moreover throughout the voyage work commands the captain. Such fishing chief center structure have roots institutive. In the case, according to legal liability by presenting solutions to the problem are as follows : firstly, The legal division Of the Sailing courses and operation course are necessary. Secondly, In the adminstrative ship official law, obligatory acquisition of the fishing Chief marine engineer qualification is necessary.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1956-1959
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• 2021

AIS(Automatic Identification System) provides navigational information including identification, position, a ship's course and status to ground and other vessels. To obtain AIS Marine Equipment Approval Service, various requirements are required and meet the requirements International Standards. However, most of the requirements are to identify essential functions, response time, hardware requirements, and communication protocols of AIS. The requirements for the quality of SW are not sufficient or detailed, and the weight is relatively low. As role of SW grows and types become more diverse, AIS SW quality inspection is essential. In this paper, We apply eight-quality characteristics of ISO/IEC 25023 standard to improve SW coverage quality of AIS. Suggest additional AIS SW requirements based on the eight quality characteristics of ISO/IEC 25023 standard.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.89-98
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• 2013

In this paper, the authors consider control system design problem of barge type surface vessel. It is based on the Dynamic Positioning System(DPS) design problem. The main role of barge ship is to carry and supply the materials to the floating units and other places. To carry out this job, it should be positioned in the specified area. Even though sometimes the thrust systems are installed on it, in general the mooring winch system with the rope is used. It may be difficult to compare the control performances of two types. But, if we consider this problem in point of usefulness, we can easily find out that the winch control system is more useful and applicable to the real field than the thrust control system except a special use. Therefore, in this paper we consider a single type mooring winch system and control system design problem in which accurate position control is needed. Because this result can be extended to the general type mooring system in which a number of winch are installed. At first, a mathematical model of winch is obtained and evaluated to verify the usefulness for control system design by experiment. Also, the disturbance model is extracted from experiment data to evaluate the strength of the uncertainty. Based on this results, the robust control system is designed and control performance is evaluated by simulation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.26-34
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• 2015

The angle of attack of a cambered otter board in a bottom trawl was estimated using a three-dimensional semi-analytic treatment of a towing cable (warp) system that was applied to the field experiments of a bottom trawl obtained by the Scanmar system. The equilibrium condition of the horizontal component and vertical component of forces was used to the three forces acting on the otter board in the horizontal plane. Those forces were the force on the warp at the bracket, hydrodynamic lift and drag forces on the otter board and the force on the hand rope attached just behind the otter board. Also the equilibrium of moment about the front edge of the otter board was used to find out the angle of attack of the cambered otter board. When the warp length was 120m and 180m long and the towing speed was between 1.23 and 1.90 m/s, the estimated angle of attack of the cambered otter board was ranged between $26.1^{\circ}$ and $29.6^{\circ}$, respectively, though the maximum lift force was at the angle of attack $22.6^{\circ}$. The angle of attack of the otter board was tended to increase weakly with the longer length of warp (180 m) at the same towing speed in the experiment.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.37-42
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• 2006

In the ocean engineering field, information about the ocean environment is important for planning, design, and operation, especially the wave information. High precision wave data is also important for considering environmental problems, like efficient operation of ships. For this purpose, many methods were considered in the past. However, an on-board directing wave measurement system has not been incorporated. The use of conventional marine radar Plane Position Indicator (PPI) images allows the estimation of wave information on a real-time basis, using both space and time information, regarding the evolution of ocean surface waves. In order to achieve data acquisition, the Radar Scan Converter (RSC) has been developed. Three-dimensional analysis was performed. The comparison of wave information derived from this system, and that of wave buoy, shows that this wave field detecting system can be a useful tool.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.430-436
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• 2008

Recently, there are many cases to use a ship's engine performance analyzer(SEPA) to measure pressure in cylinder and top dead center(TDC) of piston of engine, and analyze its performance such as fuel injection time and horsepower as well as wear of piston ring. But, SEPA needs TDC pulses($T(1){\sim}T(n)$) generated when pistons of engine are located to the TDC position ($TDC(1){\sim}TDC(n)$), these pulses are gathered from sensors connected to gear wheel of the propeller shaft in the remote distance from the measurement point. Therefore, operators need a long wire cable(WRC) to TDC detecting sensor to get these pulses, but this method is a very uncomfortable and expensive in case of installation, and it might decrease user's purchase desire. In this paper, we design and fabricate a small and inexpensive MODEM cable(M0C) so that it may be available to transmit TDC pulse generated from sensor in propeller shaft through existing power line. We also verify the facts that this MOC can be applied to SEPA and the effectiveness of the system through the experiments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.3
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• pp.165-176
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• 2009

The process of berthing/deberthing operations for entering/leaving vessels in Busan northern harbor was analyzed and evaluated by using an integrated VTS(vessel traffic service) system installed in the ship training center of Pukyong National University, Busan, Korea. The integrated VTS system used in this study was consisted of ARPA radar, ECDIS(electronic chart display and information system), backup(recording) system, CCTV(closed-circuit television) camera system, gyro-compass, differential GPS receiver, anemometer, AIS(automatic identification system), VHF(very high frequency) communication system, etc. The network of these systems was designed to communicate with each other automatically and to exchange the critical information about the course, speed, position and intended routes of other traffic vessels in the navigational channel and Busan northern harbor. To evaluate quantitatively the overall dynamic situation such as maneuvering motions for target vessel and its tugboats while in transit to and from the berth structure inside a harbor, all traffic information in Busan northern harbor was automatically acquired, displayed, evaluated and recorded. The results obtained in this study suggest that the real-time tracking information of traffic vessels acquired by using an integrated VTS system can be used as a useful reference data in evaluating and analyzing exactly the dynamic situation such as the collision between ship and berth structure, in the process of berthing/deberthing operations for entering/leaving vessels in the confined waters and harbor.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.833-838
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• 2012

TDOA which is one of the position estimation methods is used on indoor positioning, jammer localization, rescue of life, etc. due to high accuracy and simple structure. This paper proposes the super-resolution TDOA estimator using MPM(Matrix Pencil Method). The proposed estimator has more accuracy and is applicable to narrowband signal compared with the conventional cross-correlation. Furthermore, its complexity is low because obtained data directly is used for construction of matrix unlike the MUSIC(Multiple Signal Classification) which is one of the well-known super-resolution estimator using covariance matrix. To validate the performance of proposed estimator, errors of estimation and computational burden is compared to MUSIC through software simulation.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.452-459
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• 2015

It is important to use bench test results in the design process of anti-rolling tanks. Traditional bench tester is usually designed to perform only roll motions about a fixed axis and relatively small so that the viscous effects may not be neglected. Novel bench tester which could adjust the motion center to realize the coupled motion of sway and roll has been devised and manufactured therefore, large scaled bench tester could be utilized for designing the passive anti-rolling tanks. The time history of the reference signal from the rotation sensor of the bench tester have been recorded and processed to determine the phase angle to derive the Response Amplitude Operator(RAO) of the stabilized ship. The breadth of ART tank model should be large up to 2 m to diminish viscous scale effect and the vertical position of the tank can be varied with the ship's center of motion. The periods and the amplitude of roll motion can be varied from 1.5 sec to 5 sec and up to ±20°, respectively. The components of the tester was expressed in three dimensional digital mockup (DMU) and assembled together in the CAD space. The final configuration of the bench tester has been determined by confirming the smooth operation of the moving parts without interference through the animation in CAD space. New analytic logic are introduced for the determination of hydrodynamic moment and phase difference due to fluid motion in ART and verified through the test. The developed bench tester is believed to be effective and accurate for the verification of stabilization effect of ART taking into the consideration of the sway effect in the design stage.