• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.289-294
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• 2007

With regard to a marine safety system, large vessels are generally loaded with INS (Integrated Navigation System). But although small and medium-sized ships are exposed to safety accidents in the sea, they are not carrying proper navigation devices and equipment. Accordingly, in order to develop INS for small and medium-sized ships(s-INS), an existing INS has newly been organized and integrated. Recently, more strict enforcement of INS-related regulations is expected at home and abroad, and the scope of their applications is being broadened. To keep up with this global trend that ships are being loaded with digital devices and equipment, this study has tried to develop s-INS, broadening its applications, and suggesting a future research plan.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.406-415
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• 2004

The industrial environment for shipbuilding in 21st century requires increase in few type of ships and marine structures, international cooperation and globalization, while virtual enterprise environment is rapidly establishing. On the other hand, more and more efforts will be spent on internet based distributed and collaborative environment rather than being spent on unit level automations such as CAD, CAM and CAE, and the link between them. Recent internet technology and information technology in heterogeneous environment are being applied in shipbuilding industry as well as in other industries. While these technology are rapidly adopted in major shipyards, many small and medium-sized shipyards does not have enough resources to introduce system designed for large enterprise. In this paper, a prototype of Internet technology based basic planning system is implemented for the small and medium sized shipyards based on the internet technology and concurrent engineering concept. First, the system is designed from the user requirements. Then standardized development environment and tools are selected. These tools are used for defining and evaluating core application technologies for the system development. This can guarantee the survival of small and medium-sized shipyards in 21st century industrial environment.

• Bulletin of the Society of Naval Architects of Korea
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• v.3 no.1
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• pp.25-32
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• 1966

For preliminary estimation of ships' machinery weights, many papers giving well-judged data and discussions for rational method of estimation, such as [1], [2], [3], [4], [5], [6], are available, however, they are mostly concerned with large ships propelled by power more than about 2, 000 horsepower. Regarding the medium and small-sized ships, as far as the author is aware, fragmental data and vague discussions found in various technical literature are the all available. In this paper, available data concerned with machinery weights of commercial ships propelled by direct-drive diesel plants of power below 3, 000 horsepower with single screw propeller are collected and analysed to obtain systematic data Fig. 1 and Fig. 2 as weight to power ratio versus power per shaft diagrams together with suplementary data Fig. 1 and Fig. 3. Influences of various factor such as revolutions per minute, mean effective pressure, type and construction of the main units on machinery weights are also investigated in detail to give a better guidance for logical and rational utlization of the proposed diagrams in preliminary estimation of machinery weights.

• Journal of Ocean Engineering and Technology
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• v.11 no.2
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• pp.131-137
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• 1997

The technology of small and medium sized shipbuilding companies is lower relatively to major shipbuilding companies, and should be up-graded from the viewpoint of national economic development. In spite that hul form design is one of the most important elements with respect to shipbuilding technology, small and medium sized shipbuilding companies are incapable of developing hull form. Inorder to support technically such companies hull form development was carried out for G/T 999ton class tanker and D/W 4990ton class tanker which are the typical vessels operating in coastal area. The operating efficiency for the developed hull forms are impeoved by 30% for G/T 999ton class tanker and 24% for D/W 4990 tonclass tanker respectively. The results of hull form development including ship model test and performance analysis are presented in this paper.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.5
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• pp.577-587
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• 2017

The recent IMO MEPC regulation on EEDI, EEOI and increased fuel cost has worsened the financial condition of the small and medium sized passenger ferry companies, and it is situated to acquire the economic ships with a pretty high resistance performance. The purpose of this research is to develop a design method on the efficient gooseneck bulb for the middle-sized passenger ferry operated in the Far East Asian seas. The hull forms are designed by varying the gooseneck bulb parameters to find the changes on the resistance performance according to the shape of bulb. The numerical series tests are made to derive the regression equation for estimating the resistance through analyzing the data statistically. This equation is set as an objective function, and then using the optimization algorithm searches for the optimal combination of the design variables. After a hull form is designed corresponding to optimized parameters.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.661-667
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• 2020

The optimal shape modeling of core parts through 3D modeling and structural analysis for the development of small and medium-sized ships. The goal is to improve the efficient structure of the hydraulic system for controlling the rudder among the core steering parts in small and medium-sized ships. Through 3D modeling and structural analysis, a new concept of tiller parts and a double-acting hydraulic cylinder control system were proposed and operational structural stability was evaluated. Structural analysis of the three different tiller designs that can be replaceable onto existing fishing vessels was conducted to derive the final shapes. The emphasis was placed on evaluating the structural stability of the key drive components, the tiller, pin, and cylinder rodin the maximum torque condition of the hydraulic cylinder.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1734-1744
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• 2015

Majority of marine accidents that occur on fishing vessels are engine accidents. This comprises more than 26 % of the total annual fishing vessel marine accident cases. Large numbers of engine accidents happen in the cooling water system, which are mostly caused by negligence on regular check-up and repair. Notably, small-sized ships have higher engine accidents occurrence rate compared to medium-and large-sized ships. Based on the Report of the Korea Ship Safety Technology Authority, engine accident cases reached 3,032 out of the total 3,081 cases. This study researches on the differences between the small-sized ship pilot, an operator of a vessel engine of less than 200 tons, and a 6th level marine engineer, in terms of the relationship between management forms and what causes the marine accidents in association with the cooling water system. It also studies and analyzes the differences in frequency of the accident occurrence between the two groups. ${\chi}^2$ qualification was imposed through the SPSS statistical analysis program and it got qualified at the significance level of 5%. The research shall be utilized as one of the base line data for the reduction of marine accidents.

• Journal of Ocean Engineering and Technology
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• v.35 no.1
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• pp.91-97
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• 2021

Marine accidents caused by ships have brought about economic and social losses as well as human casualties. Most of these accidents are caused by small and medium-sized ships and are due to their poor conditions and insufficient equipment compared with larger vessels. Measures are quickly needed to improve the conditions. This paper discusses a video-integrated collision prediction and fall detection system to support the safe navigation of small- and medium-sized ships. The system predicts the collision of ships and detects falls by crew members using the CCTV, displays the analyzed integrated information using automatic identification system (AIS) messages, and provides alerts for the risks identified. The design consists of an object recognition algorithm, interface module, integrated display module, collision prediction and fall detection module, and an alarm management module. For the basic research, we implemented a deep learning algorithm to recognize the ship and crew from images, and an interface module to manage messages from AIS. To verify the implemented algorithm, we conducted tests using 120 images. Object recognition performance is calculated as mAP by comparing the pre-defined object with the object recognized through the algorithms. As results, the object recognition performance of the ship and the crew were approximately 50.44 mAP and 46.76 mAP each. The interface module showed that messages from the installed AIS were accurately converted according to the international standard. Therefore, we implemented an object recognition algorithm and interface module in the designed collision prediction and fall detection system and validated their usability with testing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.914-921
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• 2022

The International Maritime Organization (IMO) has set a goal of reducing ship's carbon dioxide emissions by 70% and greenhouse gas emissions by 50% by 2050 compared to 2008. Shipowners and shipyards are promoting various R&D activities such as LNG propulsion, ammonia propulsion, electric propulsion, CO₂ capture, and shaft generators as a way to satisfy this problem. The dual shaft generator has the advantage that it can be directly applied to an existing ship through remodeling. In this paper, the total fuel reduction rate that can be obtained by applying the shaft generator to the existing ship was verified through simulation. For this purpose, the size of the medium-sized ship was defined, and the governor, diesel engine, propeller, torque switch, generator for shaft generator, propulsion motor for shaft generator, and ship model were modeled and simulated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1124-1128
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• 2021

As regulations of emissions from ships become more stringent, electric propulsion systems have been increasingly used to solve this problem in vessels ranging from large merchant ships to small and medium-sized ships. Methods for improving the efficiency of the electric propulsion system include the improvement of power sources; the use of a system linked to environmentally friendly power sources, such as batteries, fuel cells, and solar power; and the development of hardware and control methodology for rectifiers, power conversion devices, and propulsion motors. The method using a phase-shifting transformer with diodes has been widely used for rectification. Power semiconductor devices with grid connection to an environmentally friendly power source using DC distribution, a variable speed power source, and the application of small and medium-sized electric propulsion systems have been developed. Accordingly, the demand for active front-end (AFE) rectifiers is increasing. In this study, a method using a neural network rather than a conventional proportional-integral controller was proposed to control the AFE rectifier. Tested controller data were used to design a neural network controller trained through MATLAB/Simulink. The neural network controller was applied to a rectification system designed using PSIM software. The results indicated the effectiveness of improving the waveform and power factor DC output stage according to the load variation. The proposed system can be applied as a rectification system for small and medium-sized environmentally friendly ships.