• Bulletin of the Society of Naval Architects of Korea
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• v.53 no.1
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• pp.35-38
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• 2016

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.5-5
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• 2017

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.827-830
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• 2008

The Center Based Navigation System(CBNS) used real time road data searches an optimal path. The other hand, the Terminal Based Navigation System(TBNS) used embedded road data searches a path that has less qualitative than the CBNS. But the TBNS has been favored, because it has no additional fees. Generally, TBNS has not used real time road data but it is recently able to use it with technique such as TPEG. However, it causes to increase a cost of exploring by using real time road data for improvement qualify of a path, because of limited performance. We propose a path-finding algorithm using a Maximum peed Dynamic Heuristic to improve quality and reduce a cost of exploring. Proposed method is to use a maximum road speed of appropriate region as dynamic heuristic for path-finding.

• Geophysics and Geophysical Exploration
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• v.7 no.4
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• pp.245-250
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• 2004

Horizontal-axes on the seismic section have been represented in a distance unit by applying horizontal-distance correction transformation on a 2-D seismic section of single channel marine seismic data. By drawing horizontal-axes in a distance unit, distortion of horizontal distances shown on the seismic section when the ship speed varies during a survey can be diminished considerably. Position information obtained by GPS and stored in each trace of seismic data as well as data collection windows were used for horizontal distance correction. The minimum window length was decided by considering ship speed and shot interval, and the maximum window length wat determined by reflecting radius of the 1st Fresnel zone. In choosing an optimum window length, horizontal resolution and stacking effect were considered simultaneously. By applying horizontal distance correction we could get a 2-D seismic section which is considered at reflecting the real subsurface structure analogously.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.741-746
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• 2010

It is necessary to estimate more accurately the resistance of barge in still water and waves to compute the break load of towline and towing power for safety towing performance. The method proposed by government has calculated the total resistance of barge which is composed of frictional resistance, wave making resistance and air resistance considering the shape of hull and towing speed. However, the added resistance is equally applied with the significant wave height regardless of the type of vessels. In this study, we have carried out the numerical calculation to estimate the added resistance of wigley model in waves and compared with the experiment data to confirm the accuracy of the method. Then the computation was executed for the barge varying shape of the bow. As a result, added resistance of barge was differently occurred i.e. 0.3∼1.1 ton according to encounter angle, 0.4∼1.2 ton according to towing speed and 0.5∼1.1 ton according to shape of bow.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.157-162
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• 2011

In this paper, we propose enhanced methods of path finding based on an abstract graph with extension of search space to improve the quality of path. The proposed methods that are called simple buffering method, velocity constrained method and distance constrained method are to extract buffering-cells for using search space with valid-cells. The simple buffering method is to extract adjacent cells of valid-cells as buffering-cells. velocity constrained method and distance constrained method are based on simple buffering method, these eliminate buffering-cells through each of threshold. In experiment, proposed methods can improve the quality of path. The proposed methods are applicable to develop various kinds of telematics application, such as path finding and logistics.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.41-47
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• 2012

Recently, due to the rapid rise of the international oil price, the burden of fuel oil expense is relatively increasing in a ship. And the international restriction of the greenhouse gas which was generated from the burning of fuel oil is also rapidly strengthened. Therefore, to reduce the greenhouse gas and fuel oil consumption, many shipping company adopted the low speed navigation and it was focused on the improvement of fuel consumption efficiency and the usage of alternative energy in the marine engine development field. In this paper, the fuel oil consumption according to the ship's speed was measured in the actual seas and analyzed the shop test results in the shipyard and the ship navigation data from the abstract log. And then it was proposed that the ship's economic speed was 14~15kts and the optimum rpm was 140~150 in specific sea conditions.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.463-470
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• 2014

In this paper, calculation of towing force required to tow the ship and experiments to verify its appropriacy are discussed. Friction, wind and wave-making resistance of vessel are considered to calculate towing force of specified vessel. Propeller resistance is also reflected and it is assumed that the propellers are locked. Node analysis to estimate additional resistance on towline is applied. Total towing force could be obtained by adding the ship's resistance and towline resistance. Experiments with training ship SAE YU DAL was executed to check the effectiveness of calculation methods and some comparison between experiments and calculation results was also done. From the comparative analysis, we confirmed that towing speed is primary terms in the calculation of towing force and propeller resistance is a major elements of ship's resistance with the increasing of towing speed. We can see that additional resistance induced by yawing of ship during towing have to be considered for total tow resistance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.868-877
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• 2011

In this paper, the feasibility of ORBCOMM satellite-based automatic identification system (SAT-AIS) is evaluated in the context of ship AIS slot collision probability depending on reporting rate, We evaluate detection probability evaluation of ORBCOMM satellite-based AIS considering link budget, SOTDMA protocol and satellite's swath width. The simulation determines the total number of vessels served by ORBCOMM satellite according to satellite's swath width, AIS slot allocation and reporting rate. By simulation results, the ORBCOMM satellite-based AIS slot collision is increased directly proportional to the total number of vessels and the more detection probability evaluation of ORBCOMM satellite-based AIS degrader, the more sip AIS reporting rate shorter.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.5-10
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• 2005

T.S. HANBADA will navigate to maintain the adequate distance between own ship and other ships safely for about 17 hours on the about 2 kts. On the above situation, M broadcasting station requires to maintain the distance from 100m to 500m between ships. This paper aims to calculate the minimum safe distance between ships, the distance is assessed by using ES Model which is a quantitative model for evaluating the difficulty of shiphandling. After marine traffic flow simulation, minimum safe distance for HANBADA on the 2kts is about 260m based ES value. On this paper, the result was compared about its distance to the actual navigating distance.