• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.279-285
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• 2019

Transverse vibrations of a ship's aft end and deckhouse are mainly induced by transverse exciting forces from the main engine. Resonance should be avoided in the initial design stages when there is a prediction of resonance between the main engine and transverse modes of the deckhouse. Estimates of frequencies for resonance avoidance are possible from the specifications of the main engine and propeller, but the inherent vibration frequency of the structure around the engine room is not easy to estimate due to the variation in the shape. Experience-oriented vibration design is also carried out, which results in many problems, such as process delay, over-injection of on-site personnel, and iterative performance of the design. For the flexible design of 8,600 TEU container vessels, this study addressed the resonance problem caused by the transverse vibration of the main engine when only the main engine was changed from 12 cylinders to 10 cylinders without modification of the hull structure layout. Efficient structural reinforcement design guidelines are presented for avoiding resonances with the main engine lateral vibration and the structure around the engine room. The guidelines are expected to be used as practical design guidelines at design sites.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.446-454
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• 2008

Control devices for fire safety systems located in a engine room are to be arranged at a safe position which is easily accessible during a fire. To develop an interpretation for the safe position in engine rooms, calculation and experiments are carried out to determine a correlation between radiant heat and distance from fire in this paper. On the basis of results of this research, the control devices for a main engine are to be installed in the behind side of an obstruction to reduce radiant heat from the fire of the main engine. In case of other control devices, they are also to be provided in the same manner of control devices for the main engine or are to be placed with 5 meters far from fire hazards.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2006.04a
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• pp.109-113
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• 2006

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.476-481
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• 2019

Early detection of fire is an important measure for minimizing the loss of life and property damage. However, fire and smoke need to be simultaneously detected. In this context, numerous studies have been conducted on image-based fire detection. Conventional fire detection methods are compute-intensive and comprise several algorithms for extracting the flame and smoke characteristics. Hence, deep learning algorithms and convolution neural networks can be alternatively employed for fire detection. In this study, recorded image data of fire in a ship engine room were analyzed. The flame and smoke characteristics were extracted from the outer box, and the YOLO (You Only Look Once) convolutional neural network algorithm was subsequently employed for learning and testing. Experimental results were evaluated with respect to three attributes, namely detection rate, error rate, and accuracy. The respective values of detection rate, error rate, and accuracy are found to be 0.994, 0.011, and 0.998 for the flame, 0.978, 0.021, and 0.978 for the smoke, and the calculation time is found to be 0.009 s.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.127-132
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• 1975

This is an experimental study that aimed to find out a possible relationships between the noise of the ship and the intelligent quotient, and the creativity of the crew member during June 5, to August 24, 1975. The experiment was carried out on the university training ship, the Oh-Bae-San Ho(1,126 tons), and the Kwan-Ak-San Ho (243 tons) and the training ship Baek-Kyung Ho (380 tons) of Je-ju College, where the total number of 144 students engaged on their tasks of practical exercise. And the following results were obtained : The decreases of I.Q. was evident as compared to the score obtained at the class room; soon after the embarking of the ship, the students on the deck decreased the score by $7\%$ of what they obtained at the class room while the students in the engine room decreased by $13\%$. The I.Q. was regaining the normal state after three days of embarking seemingly showing the fact that the students became adapted to the noise of the ship, but no remarkable improvement was visible during the period of 3 days to 35 days on the ship. One of the remarkable fact that had not been expected was that the problems for audio discernment was much easily solved in the midst of noise that made oral communication impossible (102 dB) than in the place of noise where conversation was possible(67 dB).

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.569-574
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• 2011

In research vessels or naval ships, airborne noise from machineries such as diesel engine is the major source of underwater noise at low speed. In this paper, effect of engine noise on underwater noise is studied by considering two paths; sound radiation from hull plate and direct airborne noise transmission through hull plate. SEA (Statistical energy analysis) is used to predict hull plate vibration induced by engine noise, where SEA model consists of only two subsystems; engine room air space and hull plate. The pressure level in water is calculated from sound radiation by plate. Engine noise transmission through hull plate is obtained by assuming plane wave propagation in air-limp plate-water system. Two effects are combined and compared to the measurement, where speaker is used as a source in engine room and sound pressure levels in engine room and water are measured. The hydrophone is located 1 m away from the hull plate. It is found below 1000 Hz, prediction overestimates underwater sound pressure level by 5 to 12 dB.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.63-69
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• 2011

Exhaust gases of a vessel from a main engine, a diesel generator and an incinerator contain very harmful substances like soot, $SO_2$ and NOx. Careful design of funnel shape is required to prevent those harmful exhaust gases from influencing on accommodation and a fan room. Meanwhile, the exhaust gases are also hot enough to damage electronic devices like radar. Therefore the funnel design should be considered so that electronic devices are not directly exposed to the exhaust gas in the strong stern wind. This study may propose guidelines of optimum design criterion for the anti-thermal damage design of the electronic devices and anti-recirculating design of harmful exhaust gas near the accommodation. From CFD analyses, we can understand that the major factors affecting the exhaust gas dispersion are the large scale mixing by separation vortices and the sluggish flow in the recirculation region. We hope that the funnel flow analysis around ship's funnel is used for practical optimum funnel design to minimize the exhaust gas dispersion by adjusting the funnel shape, the position of the exhaust pipe, the shape of bulwark, the exhaust direction of air ventilated an engine room and the angle of the exhaust pipe.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.329-330
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• 2008

The 181,000 DWT Bulk Carrier has a different deck house type, which is not typical for previous bulk carriers, to meet the new international rules for bulk carriers. This new deck house has much smaller transverse breadth than the hull's transverse breath, resulting in large levels of the transverse response of the deck house. In addition, the longitudinal response of the funnel showed rather a large magnitude of vibration, which are excited by the ship's main excitations such as the main engine H-moment and the propeller surface forte when the ship operates at the NCR and the MCR speeds In the ballast condition. To solve these issues, the global forced vibration analysis has been performed for the ship and the ship structure has been modified to reduce the vibration level by increasing the girder depth and adjusting the engine room tank arrangement.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.119-128
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• 2004

Recently, the accidents on the sea have arisen due to the increase of the nautical traffic and the digitization of equipments for marine. Therefore, IMO(International Maritime Organization) have provided the recommendation of EMI and EMS for radio communication and equipments of marine from SOLAS convention at July 1st 2002. In this paper, we measured EMC environment on the Hanbada, which is Korea Maritime University training ship, for basic EMC environment of ship. The measuring point was Bridge and Engine Control Room of the ship, we measured at the test point that was set at random. Measured Band is from 30 MHz to 2 GHz, polarization measurement is processed both vertical and horizontal polarization. We analysed the results in consideration of permissible criteria.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.141-146
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• 2005

Recently, the accidents on the sea have arisen due to the increase of the nautical traffic and the digitization of equipments for marine. Therefore, IMO(International Maritime Organization) have provided the recommendation of EMI and EMS for radio communication and equipments of marine from SOLAS cobvention at July 1st 2002. In this paper, we measured EMC environment on the HANBADA, which is Korea Maritime University training ship, for basic EMC environment of a ship. The measuring point was Bridge and Engine Control Room of the ship, we measured the test point that was set at random. Measured Band is from 30 MHz to 2 GHz, polarization measurement is processed both vertical and horizontal polarizaion. We analysed the results in consideration of permissible criteria.