• Journal of Intelligence and Information Systems
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• v.12 no.1
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• pp.75-93
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• 2006

The ship selection by consignors has two steps to carry their cargo. The first step is to select according to time schedule of ships and amount of cargo, and the second one is re-selection by concentrating different consignors' cargo into a unit that can be carried by single ship. Up to now, these steps are usually done by hands leading to inefficiency. The purpose of our paper is to form a logistics chain to minimize the overall sum of logistics cost by selecting ships for consignors' cargo using negotiation methodology between agents. Through concentration and distribution of cargo, maximization of global profit derived from searching optimal point in trade-off between inventory cost and freight rate cost. It is settled by the negotiation between consignors. In the experiments, two methods of the first-step of ship selection: EPDS(Earliest Possible Departure-Date Scheduling) and LPDS(Latest Possible Departure-Date Scheduling) coupled with the second-step ship concentration method using the negotiation were shown. From this, we deduced inventory cost, freight rates and logistics cost according SBF(Scheduling Bundle Factor) and analyzed the result. We found it will minimize the total logistics cost if we use negotiation method with EPDS.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.15-22
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• 2009

Auto-navigation algorithm have been studied to avoid collision and grounding of a ship due to human error. There have been many research on collision avoidance algorithms but they have been validated little on the real coastal traffic situation. In this study, a Collision Avoidance algorithm is developed by using Fuzzy algorithm and the concept of Changeable Action Space Searching (CAS). In the first step, on a basis of collision risk calculated from fuzzy algorithm in the current time(t=to), alternative Action Space for collision avoidance is planned. In the second step, next alternative Action Space for collision avoidance in the future($t=to+{\Delta}t$) is corrected and re-planned with re-evaluated collision risk. In the third step, the safest and most effective course among Action Space is selected by using optimization method in real time. In this paper, the main features of the developed collision avoidance algorithm (CAS) are introduced. CAS is implemented in the ship-handling simulator of MOERI. The performance of CAS is tested on the situation of open sea with 3 traffic ships, whose position is assumed to be informed from AIS. Own-ship is fully autonomously navigated by autopilot including the collision avoidance algorithm, CAS. Experimental results show that own-ship can successfully avoid the collision against traffic ships and the calculated courses from CAS are reasonable.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.221-226
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• 2012

This research presents an analysis of algorithm for ship track-keeping along a given trajectory. The maneuver of a free running model ship guiding through a simple path are presented. In order to solve the above problem, a desired trajectory is usually determined by GPS points in a pre-fixed place then these points are set in a pre-programmed navigation so that the ship would be automatically tracked. Proportional-Derivative(PD) control which is useful for fast response controllers was used in this program as a course keeping system. A high accuracy GPS receiver was installed on the model ship that could provide positions frequently, the system will compare and give out the remaining distance and heading to the target way-point. The results of ship auto track-keeping experiment will be explained in order to illustrate the adjustment in controlling parameters. These results can be utilized as a preliminary step to carry out the experiment of ship collision avoidance system and automatic berthing in the future.

• Journal of Navigation and Port Research
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• v.30 no.5 s.111
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• pp.321-329
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• 2006

The ultimate target cf this study is to develop ship's Digital Compass that can substitute for conventional ship's Magnetic Compass. At first, a new Digital Compass system consisting of three-axis Flux-gate sensors and small sized step motor was developed Then, new deviation adjustment theory incorporating with Kalman filter method was proposed through which automatic deviation analysis and correction are obtainable without ship's swinging procedures. The effectiveness of developed Digital Compass and proposed deviation adjustment theory are verified throughout the performance evaluation tests on the training ship 'SAE-NU-RI'.

• Journal of Navigation and Port Research
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• v.31 no.4
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• pp.281-287
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• 2007

Human factors have been considered the primary reason of marine accidents. Especially, the collision between vessels is mostly mused by human behavior. However, there have not been many researches to clarify the reason of marine accidents mused by human factors quantitatively. In order to understand human factors and to enhance safe navigation systematically, using a full mission ship-handling simulator, we've investigated the characteristics of avoiding behavior taken by mariners. Further in order to apply the characteristics more widely and effectively, it's necessary to formulate the standard behavior for ship-handling in the condition of collision avoidance. Is this study, therefore, we intended to propose the concept to model the mariner's standard behavior on the handling of collision avoidance as the first step. As a result, we confirmed the contents of information processing in ship-handling that mariner's generally taking to avoid collision.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.77-85
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• 2006

The last target of this study is to develop ship's Digital Compass that can be substitute with conventional ship's Magnetic Compass. At first, new Digital Compass system was developed with three-axis high accuracy Flux-gate sensors and small sized step motor. Then after, new deviation correction theory without ship's swinging procedures was proposed to provide automatic deviation analysis, correction and renewal. Throughout the performance evaluation tests on the training ship 'SAE-NU-RI', the effectiveness of developed Digital Compass and proposed deviation correction theory are verified.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.438-444
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• 2018

Korea has recently selected twenty-two ports for reinforcement breakwater installation of protection facilities, due to rise sea level caused by global warming and increase in the number of typhoon and tsunami. In addition, due to consistent enlargement of ship size, dredging for depth of water for large vessel's berthing and enlargement of berth is under construction. However, no definite construction plan for the reinforcement and lengthening of crown height, which has close relationship with the safe mooring of ships. In this study, domestic and foreign design criteria of crown height were analyzed, and the crown height evaluation index and evaluation method were developed by dividing it into environment and ship elements. In particular, in the case of ship evaluation index, each step was set up in 4 steps according to domestic and foreign regulations, weighted by each step, and the safety level of crown height was evaluated. As a result of the mooring safety simulation of the 100,000 ton cruise ship, the appropriate minimum crown height standard was derived to be 3 m above A.H.H.W. The results of this study are expected to be used as basic data to propose the crown height standard reflecting ship characteristics.

• Korean Journal of Remote Sensing
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• v.33 no.4
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• pp.437-444
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• 2017

Since land pixels often generate false alarms in ship detection using Synthetic Aperture Radar (SAR), land masking is a necessary step which can be processed by a land area map or water database. However, due to the continuous coastline changes caused by newport, bridge, etc., an updated data should be considered to mask either the land or the oceanic part of SAR. Furthermore, coastal concrete facilities make noise signals, mainly caused by side lobe effect. In this paper, we propose two methods. One is a semi-automatic water body data generation method that consists of terrain correction, thresholding, and median filter. Another is a dynamic land masking method based on water database. Based on water database, it uses a breadth-first search algorithm to find and mask noise signals from coastal concrete facilities. We verified our methods using Sentinel-1 SAR data. The result shows that proposed methods remove maximum 84.42% of false alarms.

• Journal of Korea Ship Safrty Technology Authority
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• s.27
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• pp.25-36
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• 2009

Despite the development of the various navigational equipment, such as GPS, ARPA, ECDIS, AIS, VDR, and hull monitoring system, marine accidents are still a leading concern in shipping industry. For all accidents over the reporting period, approximately 60 to 80% of the accidents was involved in human error. It means that in each case, some events which were associated with human error initiated an accident, and those failures of human performance led to the failure to avoid an accident or mitigate it's consequences. However, the improvement and the effort on the maritime human error are still limited in an elementary step. The objective of this paper is to propose a modified Human Factors Analysis and Classification System (HFACS) model in order to analyse the collision accidents of tug-barge ship.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1234-1237
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• 1993

This paper discusses the hull form generation from fuzzy model constructed with actual ship data using fuzzy concept. SAC, which is the most important factor in the hull form generation, is expressed by a fuzzy model describing the relationships among design parameters, which have a great influence on SAC, through model identification process with the actual ship data and design parameters. Then, we can infer the SAC of an aimed ship through the process of fuzzy inference and decide the offset of a front view by making the fuzzy model between SAC and offset as well. In conclusion, this paper makes a step forward from the geometrical definition, which has been used for hull form generation so far, to direct mathematical formulae about the relationship between design parameters and offset. So, if the design parameters are given, we can generate the hull form taking such properties into account.