• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.960-964
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• 2005

Digital Virtual Manufacturing is a technology to facilitate effective product developments and agile productions by digital models representing the physical and logical schema and the behavior of real manufacturing systems including products, process, manufacturing resources and plants. A digital virtual factory as a well-designed and integrated environment is essential for successful applications of this technology. In this research, we constructed a sophisticated digital virtual factory of the shipbuilding company's section steel shop by 3-D CAD and virtual manufacturing simulation. This digital virtual factory can be applied for diverse engineering activities in design, manufacturing and control of the real factory.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.53-62
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• 2023

This paper has suggested the necessity of introducing training contents using XR(Extended reality) technology as a way to lower the high rate of nursing accidents among unskilled technical personnel in domestic shipbuilding industry, focusing on cable pulling using winch. The occurrence rate of nursing accidents in the domestic shipbuilding industry was almost double(197.4%) (2017~2020) when compared with other manufacturing industries. In particular, it is worth noting that more than 31.8% of nursing accidents in the shipbuilding industry occurred among workers whose job experience is no more than 6 months. Most of new workers are seen to have hard time due to several factors such as lack of work information, inexperience, and unfamiliarity with the working environments. This indicates that it is essential to incorporate more effective training method that could help new workers become familiar with technical skills as well as working environments in a short period of time. Currently, education/training at the domestic shipyard is biased toward technical skills such as welding, painting, machine installation, and electrical installation. Contrary, even more important training required to get new workers used to the working environment has remained at a superficial level such as explaining ship building processes using 2D drawings. This may be the reason why it is inevitable to repeat similar training at OJT (On-the-Job Training) even at the leading domestic companies. Domestic shipbuilding industries have been attracting a lot of new workers thanks to recent economic recovery, which is very likely to increase the occurrence of disasters. In this paper, the introduction of training using XR technology was proposed, and as a specific example, the process of pulling cables using winches on ships was implemented as XR-based training content by using Unity. Using the developed content, it demonstrated that new workers can experience the actual work process in advance through simulation in a virtual space, thereby becoming more effective training content that can help new workers become familiar with the work environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1854-1864
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• 2011

Production planning is one of the most important activities in shipbuilding enterprises. Shop-floor supervisors and planners still do not have enough information to effectively analyze shop operations because of the difference between production planning and shop-floor scheduling. In this paper, process analysis was conducted between production planning and shop-floor control to clarify the difference, and the necessity of the manufacturing execution system(MES) was derived in a shipyard. Therefore, the simulation-based ship production execution system(SPEXS) was defined by analyzing characteristics of MES. The architectural functions of the system were deducted from the process of requirement analysis. The SPEXS' framework was constructed on the basis of the architectural functions. This framework will provide more reliable production schedules and allow engineers to plan and control shop operations in real-time.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.3
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• pp.104-112
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• 1997

Line heating process has been used in forming hull surfaces long before and it has depended on skillful workers. As the reduction of production cost is major concern of shipbuilding companies, line heating work must be improved for higher productivity. In this paper, as the first step to automatic hull forming, a method is proposed to predict deformations due to line heating. It includes a simplified thermal elasto-plastic analysis to increase computing efficiency and to do real time visualization of deformed shapes. For the prediction of deformation, a method to estimate heat flux of the torch is also introduced. Predicted deformations for line heated plates show good agreement with experimental results. The proposed method can be used in control and simulation of line heating process with ease.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.4
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• pp.66-74
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• 2001

Plate bending process is indispensible in shipbuilding. The process includes press bending process and heating process. Especially the heating process is carried out exclusively by skillful workers. Many researches have been made to automate the heating process. This study was carried out as a fundamental study to develop a efficient analysis method for triangle heating and focused on clarifying the deformation characteristics of plate by triangle heating and essential elements effect on the deformation. In this paper, we proposed an analysis model for thermal-elastic-plastic analysis and simulated the deformation by triangle heating using ANSYS based on the experimental results of Jang et al.(2001). Also, we showed the deformation characteristics more clearly by comparing the deformation due to triangle heating and line heating in case that the total heat input is same. Finally, we investigated the change characteristics of deformation elements according to the volumetric heat input.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.620-628
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• 2017

In this paper, we suggest a route plan sharing service for the navigation assistance service which is the second item of 16 items in maritime service portfolios (MSPs) for safety navigation based on interview process. Also, we developed scenarios for effectiveness evaluation of the proposed service, and conducted simulations using full mission ship handling simulator (FMSS) for effectiveness evaluation of proposed services based on the developed scenarios. Through the simulations, we analyzed proximity measures, controllability statistics and subjective evaluations to assess the usefulness of suggested service. If accomplishing the test for new services to apply real ships and vessel traffic (VTS) center, there has possibilities to occur various risks in terms of time/cost problems. Therefore, there is needs for the preliminary effectiveness evaluation processes necessarily when adopts and implements new services. Because we expected the service that is helpful for safety navigation, but the test results are not when conducted a simulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.10-16
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• 2013

This paper discussed a procedure for noise certification of Aircraft and predicting the full scale over-flight noise of propeller from acoustic wind tunnel measurement of small scale propeller. Noise Certification Procedures is established from International Civil Aviation Organization(ICAO). The data manipulations are then discussed in extrapolation to simulation flight distance and flight simulation. One of the most important point of flight simulation is adjustments for differences between wind tunnel test conditions and flight test conditions. To simulated the noise level estimation procedure for noise data post-process, simulate procedures from data of the wind tunnel noise measurement and the flight noise measurement by using a 7kg degree UAV. This study confirmed an effectively noise estimation procedures by wind tunnel noise test and flight noise test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4717-4722
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• 2014

In shipyards, a large number of dog-pieces are used to align welding joints and prevent welding deformation in the block assembly stage. The huge working man-hours consumed in the working process of dog-pieces impedes the productivity growth of shipyards. In this study, an analysis method based on the experimental results was proposed to simulate the welding deformation of butt joints with a dog-piece setting. The simulation of welding deformation of a hull block joint was performed using the proposed analysis method. Finally, the proposed analysis method can be used to establish guidelines for the proper use of dog- pieces in the block assembly stage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.7
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• pp.573-581
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• 2014

We proposed a hopping phase estimator to demodulate the received signals without any hopping information in frequency hopping spread spectrum systems. The demodulation process in this paper is as follows: hopped frequency tracking is accomplished by choosing a frequency component with maximum amplitude after taking discrete Fourier transform and a hopping frequency estimator which estimates the phase generated by hopped frequency is established through difference product and down-sampling. We obtained the probability density function and variance performance of the proposed estimator and confirmed that the analysis and the simulation results were agreed with each other.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.66-71
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• 2013

Soft bending pipe is widely used for freezing equipment and shipbuilding. These pipe have some problems that they cause occasionally outside wrinkle, crack, wall thinning phenomena. However, vending machines which have been made to solve the problems completely, are not yet. In this study, to settle these problems, we proved the effectiveness of the self-made mandrel by results of simulation as the basic for the development of precision high-quality vending machine ; presents the solution method of the wall thinning phenomena by analyzing circular deformation and damage of bending pipe.