• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.2
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• pp.100-108
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• 2002

A fuzzy logic for collision avoiding navigation of marine vehicles is proposed in this paper. VFF(Virtual Force Field) method, which is used widely in the field of mobile robots, is modifiel to apply to marine vehicles. The method is named MVFF (Modified Virtual Force Field) mothod. The MVFF consists of the determination of the heading angles far track-keeping mode ($\psi_{ca}$)and collision avoidance mode ($\psi_{ca}$). The operator can choose the pattern of the track-keeping mode in the proposed algorithm. The collision avoidance algorithm can handle static and/or moving obstacles. These functons are implemented using fuzzy logic. Various simulation results verify the proposed alogorithm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.S1
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• pp.89-109
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• 1996

The main information for a marine navigation is ship's bearing obtained from Gyro, Gyrocompass, Magneticcompass and electronic navigation systems such as LORAN, OMEGA and GPS. However, some of these systems have a disadvantage or restricted conditon involved critical problems in a war-ship and weapon system. In the work, we have done the basic resrarch, analysis of error pattern for GPS, for the development of the ship's seondary bearing sensor (GPS-Compass) to provide the back-up system of Gyro/Gyrocompass and a substitution way of Magneticcompass.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.118-119
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• 2005

Recently, fire extinguishing systems based on water mists have been attracting public attentions in marine engineering. Performance of the fire extinguishing systems is influenced by the size and distribution of spayed water mists. Droplet analyzing method based on image processing technique for measuring droplet size and distribution has been developed. The morphological method based on partial curvature information of pre-processed images was adopted for recognition and separation of overlapped particles. Tested results show that the present method may be reliable for the analysis of the size and distribution of droplets produced by water mist spay flow.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.99-105
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• 2000

For multi-body dynamic problems. especially coalescent eigenvalue problems with multiobjective optimization, the design sensitivity analysis is too much complicated mathematically and numerically. Therefore, this article proposes a new technique for structural dynamic modification using a mode modification and homologous structures design method with Genetic Algorithm(GA). In this work, the homologous structure of the resiliently mounted multi-body for marine diesel generator systems is studied and the problem is treated as a combinational optimization problem using the GA. In GA formulation, fitness is defined based on penalty function approach. That include homology, allowable stress and minimum weight of common plate.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.307-308
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• 2006

Recently, fire extinguishing systems based on water mists have been attracting public attentions in marine engineering. Performance of the fire extinguishing systems is influenced by the size and distribution of spayed water mists. Droplet analyzing method based on image processing technique for measuring droplet size and distribution has been developed. The morphological method based on partial curvature information of pre-processed images was adopted for recognition and separation of overlapped particles. Tested results show that the present method may be reliable for the analysis of the size and distribution of droplets produced by water mist spay flow.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.281-286
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• 1997

Recent construction activities and maintenance of marine facilities have been accelerating to keep up with rapid economic growth in Korea. Marine concrete structures are exposed to salts an chloride from ocean environments. The corrosion of reinforcement steel caused by chloride-penetration into concrete may severely effect the durability of concrete structures. The objective of this research is to develop a durable concrete by investigating the corrosion resistance of various corrosion protection systems utilizing different water/cement ratio, silica fumes, corrosion inhibitors and etc. A tow-year verification test on various corrosion protection systems has been doing in the laboratory and at the seaside. Corrosion investigations on reinforcement steel are now under progress for more than 180 concrete specimen. Corrosion-related measurements include macrocell corrosion current, instant-off voltage between corroding and noncorroding reinforcement, chloride contents, the corroded surface areas on the reinforcement steel, and etc. A low level of corrosion is investigated on reinforcement steels in concrete specimen made with corrosion inhibitors or applied aqueous impregnating corrosion inhibitors into their surface, even though high chloride contents of concrete specimen.

• New & Renewable Energy
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• v.20 no.2
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• pp.2-16
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• 2024

Various loads induced by marine environmental conditions, such as waves, currents, and wind, are crucial for the operation and viability of offshore wind power (OWP) systems. In particular, waves have a significant impact on the stress and fatigue load of offshore structures, and highly reliable design parameters should be derived through extreme value analysis (EVA) techniques. In this study, extreme wave analyses were conducted with various Weibull distribution models to determine the reliable design parameters of an OWP system suitable for the Ulsan area. Forty-three years of long-term hindcast data generated by a numerical wave model were adopted as the analyses data, and the least-squares method was used to estimate the parameters of the distribution function for EVA. The inverse first-order reliability method was employed as the EVA technique. The obtained results were compared among themselves under the assumption that the marginal probability distributions were 2p, 3p, and exponentiated Weibull distributions.

• Korean Journal of Computational Design and Engineering
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• v.19 no.1
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• pp.41-49
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• 2014

For the reuse of the existing 3D block model of a ship, we analyze the hull modeling process using AVEVA Marine which is a representative CAD (Computer-Aided Design) system for the shipbuilding. In the AVEVA Marine environment where the design engineer makes 3D model on the 2D view that is so-called 2.5D, it cannot be possible to copy to reuse the block model just simply copying the 3D feature model itself like in the general mechanical CAD system or Smart Marine 3D which are on the basis of the 3D model representation. In this paper, we analyze the scheme file where the 3D model is defined in AVEVA Marine so that we develop the program for the block copy and the translation using this scheme file. It is significant that this program can be immediately available as a real-world application on the AVEVA Marine environment.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.137-150
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• 2011

Nationally and internationally reported statistics on marine accidents show that 80% or more of all marine accidents are caused fully or in part by human error. According to the statistics of marine accident causes from Korean Maritime Safety Tribunal(KMST), operating errors are implicated in 78.7% of all marine accidents that occurred from 2002 to 2006. In the case of the collision accidents, about 95% of all collision accidents are caused by operating errors, and those human error related collision accidents are mostly caused by failure of maintaining proper lookout and breach of the regulations for preventing collision. One way of reducing the probability of occurrence of the human error related marine accidents effectively is by investigating and understanding the role of the human elements in accident causation. In this paper, causal factors/root causes classification systems for marine accident investigation were reviewed and some typical human error analysis methods used in shipping industry were described in detail. This paper also proposed a human error analysis method that contains a cognitive process model, a human error analysis technique(Maritime HFACS) and a marine accident causal chains, and then its application to the actual marine accident was provided as a case study in order to demonstrate the framework of the method.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.5
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• pp.475-481
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• 2005