• Journal of the Society of Naval Architects of Korea
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• v.46 no.2
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• pp.171-178
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• 2009

In this paper, RFID (Radio Frequency Identification) based management system is introduced to control effectively logistic supply items and machinery spare parts in a ship. To apply an RFID system under very harsh environment in a ship which is a steel-structured small area with lots of compartment, we measured reading distances and angles in open space, in an steel compartment, and an real ship separately in order to investigate the reliability between various tags and RFID.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.709-718
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• 2021

As regulations on environmental pollution of ships have been strengthened, interest in smart ships such as electric propulsion ships equipped with hybrid power systems is increasing. Since batteries used in electric propulsion ships have a larger capacity than batteries used in vehicles, the price is high and maintenance is considered important. The ship's battery is manufactured as an integral type and is managed by the battery management system, and the maintenance and repair of the battery is performed through the replacement of the battery. we design and implement a battery module and a control algorithm using pre-cell for easy battery management. In addition, a controller is designed to transmit the data necessary for the electric propulsion ship power system control to the power control system. When a battery to which the corresponding spare-cell is applied is used, the stability of the ship and the battery system is increased, and it can have an advantage in terms of maintenance and repair.

• Journal of Navigation and Port Research
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• v.44 no.4
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• pp.354-361
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• 2020

The term "articles for ship" is a general term for all relevant mechanical accessories (SPARE) and consumable materials (STORE) commonly used in ships. Ships commonly are at sea, so it is difficult to respond rapidly to the demand for them in an emergency situation. In particular, it is more difficult to determine the boarding location of tramper ships as it is more difficult to predict the next sailing route in advance. The purpose of this study was to identify the important factors to be considered in determining the boarding location of tramper ships through a survey of each ship owner and ship management company. This valuable information on the proposed supply procedures for each country and port, would be an efficient way to supply articles for ships.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4560-4570
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• 2022

Dynamic fault tree (DFT) and its related research methods have received extensive attention in safety analysis and reliability engineering. DFT can perform reliability modelling for systems with sequential correlation, resource sharing, and cold and hot spare parts. A technical modelling method of DFT is proposed for modelling ship collision accidents and loss-of-coolant accidents (LOCAs). Qualitative and quantitative analyses of DFT were carried out using the cutting sequence (CS)/extended cutting sequence (ECS) method. The results show nine types of dynamic fault failure modes in ship collision accidents, describing the fault propagation process of a dynamic system and reflect the dynamic changes of the entire accident system. The probability of a ship collision accident is 2.378 × 10^-9 by using CS. This failure mode cannot be expressed by a combination of basic events within the same event frame after an LOCA occurs in a marine nuclear reactor because the system contains warm spare parts. Therefore, the probability of losing reactor control was calculated as 8.125 × 10^-6 using the ECS. Compared with CS, ECS is more efficient considering expression and processing capabilities, and has a significant advantage considering cost.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.128-133
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• 2006

This study is focused on the skill to prevent RIB (Rigid Inflatable Boat) from sinking. For better ability to prevent sinking, single hypalon tube is replaced by double TPU (Thermoplastic Polyurethane) tube that is excellent at frictional wear strength and oil-resisting qualities. High buoyant materials are arranged in empty spaces of ship so that ship's spare buoyancy is increased. And for restoration of stable position of ship, the self-righting system is installed. Aluminium alloy is used for increasing hull strength.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.5
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• pp.966-978
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• 2014

Currently, majority small ship's clutch for power transmission to propeller relies on multi plate hydraulic clutch regardless its size. Most of the small ships do not have a spare equipments of clutch. Furthermore, many ship engineers do not have an ability as well as enough experience to solve this problem related to the hydraulic clutch during the voyage. Therefore, any small problems cause many serious marine accidents. Once the clutch has problem, almost of all ships can not sail by itself anymore and it must be towed by salvage boat, maritime police ships, or fish guidance boat etc. In this case, all the accidents will be categorized as a marine accident and they all need to go through marine accident court inquiries. In this study, an understanding of each crew on hydraulic clutch system has been profoundly measured. Furthermore, the knowledge on an emergency navigation protocol of each crew has been also profoundly checked. Additionally, various surveys on hydraulic clutch classes has been performed and its satisfaction of crews on this topic have been carefully checked based on various feedback from students who took these courses. All of the above data from this study will be used to reduce marine accidents in current marine industry.

• Korean Management Science Review
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• v.30 no.3
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• pp.17-31
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• 2013

The purpose of this paper is to illustrate the importance of identifying and considering 'purchase dependence' when purchase of an item is dependent on availability of other items demanded in the same order. This paper is the first study to develop an inventory model for purchase-dependent inventory systems. Through simulation experiments, we demonstrate that the developed inventory model incurs less inventory operations cost than other inventory models that ignore purchase dependence. For empirical validation of the developed inventory model, the actual inventory data at the Hyundai Engine Europe Service Center is used. We explain the process of identifying purchase dependencies among items through a data mining technique. The empirical study results in similar results to the simulation experiment, demonstrating that the developed inventory model is applicable to real situations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.193-201
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• 2014

This study provided safe sailing speed and appropriate passing time to areas of known strong current water to prevent marine accident of the ships. To the interpretation of these data which target Myeongnyang waterway, AIS data of the ship was collected from $12^{th}$ July to $15^{th}$ July 2010 and site environment was investigated on $4^{th}$ September 2010. On the basis of the collected data, the 'Minimum Navigation Speed' and 'Optimum Navigation Speed' were calculated. It has also considered the 'Spare control force' or allowance and the 'Respond Rudder Angle' for each tidal current speed. Additionally, it suggested the safe passing time to strong current area by analyzing tidal level and tidal current speed. The conclusion of the research are as follows : (1) If the flow rate is greater than 4.4 kn, it is difficult for the model ship to control herself by her own steering power and to cope with tidal current pressure force and yaw moment caused by the tidal current.. (2) The minimum navigation speed should be over 2.3 times the tidal current and the optimum navigation speed should be over 4.0 times the tidal current. (3) When spring tide, the optimum passing time at Myeongnyang waterway is between 30 minutes to 1 hour before the time of high/low water, and at 5 hours after high/low water, passing of ships should be avoided because it is time when the flow rate is over 4 kn.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.26-32
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• 2017

Enlargement and speed-up of a ship and diversification of ship's type have served to greatly increase the importance of marine transport means. It's reported that accident occurrence frequency of collision is high next to engine damage among the ship accident types, and that the accident ratio according to human factors is also high. In addition, ship accidents come to occur caused by complex cause factors rather than a sole cause factor, it is necessary to investigate the cause factors through the written verdict. This study proposed the cause factors of collision ship accident on the basis of human factors in collision ship accident among the written verdicts provided by the Korean Maritime Safety Tribunal, and inquired into the cause factor and effect through the correlation analysis of accident occurrence factors. Also, this study predicted the collision accident through analyzed the major cause factor of the occurrence at the zero minute when collision on the basis of the time taken from the time point of detecting collision of ships to the time point of collision occurrence. This study used commercial software-Statistical Package for Social Sciences (SPSS Ver21.0) to do correlation analysis. For time analysis, this study analyzed the cause factor and time by analyzing the time taken from the time point of detected ships to the time point of collision occurrence on the basis of the written verdicts. The study analysis showed that there were many cases of collision ship accidents occurrence caused by more than two sorts of cause factors, and that the case (zero minute) where there is no time to spare for collision avoidance accounted for 36.1 %, and negligence in guard or surveillance of the other ship, and sailing while drowsy, or drinking was a contributor to an accident. Poor watch keeping is very strong relationship with pool ready for sail.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.1
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• pp.31-36
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• 2013

Maritime University cadets must be on board ship's after thoroughly completing a Basic Safety Training Course. During their spare semester they must complete basic principle of the course and then, attend to both Advanced Safety Training Course and Tankers Training Course before they graduate. However, all cadets are exposed to risks during their onboard training. It means that most of commercial ships have to train them before boarding and perform duties according to all sorts of check lists based on the ISM. Accordingly, this research will deal with the treatment for toxic chemicals which is not fully covered by shipping firms, vessels and even a Maritime University for cadets. The lack of pre-knowledge about it is considerably hazardous to the cadets who have no onboard experience. As stated above, the majority of the onboard cadets board their ships without previous training on treatment and knowledge for toxic chemicals. As a result, there are some cases that cadets are injured due to the lack of knowledge to treat toxic chemicals and due to carelessness. Furthermore, they end up leaving a ship prematurely. To prevent these incidents from occurring, this paper recommends thorough training before going onboard provided by Maritime University, the systematic database on the safety of the toxic chemicals and the development of the online contents for safety education of toxic chemicals fitted on each ship's types are necessary to avoid risks and accidents onboard. Furthermore, it is suggested that shipping companies should manage the ship according to the safety check list on toxic chemicals and the crew in charge with qualification for the treatment of toxic chemicals should provide a safety education and supervision.