| 1. |
- Jeong, Yong-Kuk, 1989-, et al.
(författare)
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A Spatial Layout Optimization Program considering the Survivability of a Naval Vessel in the Early Design Stage
- 2019
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Ingår i: Journal of Ship Production and Design. - : Society of Naval Architects and Marine Engineers. - 2158-2866 .- 2158-2874. ; 35:2, s. 126-138
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Tidskriftsartikel (refereegranskat)abstract
- As mission capability and scope of naval vessels are increasing, there has been an emphasis on the importance of survivability of naval vessels. Elements of survivability include susceptibility, vulnerability, and recoverability among which vulnerability is directly associated with the interior spatial layout of a naval vessel. However, various other elements also must be simultaneously considered in the design phase of a naval vessel. Accordingly, this study proposes a method that considers survivability an assessment factor by quantifying vulnerability in attacks, which is directly associated with the effect of spatial layout of a naval vessel. Furthermore, to automatically create spatial layout alternatives of naval vessels and efficiently deduce optimum spatial layout results, this study developed an optimization program for the spatial layout of naval vessels. The differential evolution algorithm was used for the optimization, and its effectiveness was validated by applying it to various examples.
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| 2. |
- Kim, Youngmin, et al.
(författare)
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Computational Shipyard Dynamics
- 2018
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Ingår i: Journal of Ship Production and Design. - : The Society of Naval Architects and Marine Engineers. - 2158-2866 .- 2158-2874. ; 34:4, s. 355-367
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Tidskriftsartikel (refereegranskat)abstract
- Early simulations focused mainly on virtualizing the shipyard itself and the approach in terms of production management that focuses on improving productivity was hardly sufficient. For systematically approaching shipyard production problems, to which the dynamics between various factors are applied, this study uses the shipyard simulation information model to explain the six factors, which are the input variables of the shipyard production system simulation. Then, the objective or output variable is set up as the key performance index (KPI) by aligning the interests from an enterprise perspective. The output variable, KPI, is generally expressed as a function of functions of the input variables, namely a functional. To evaluate the value of the functional, a computational method in the form of a simulation is used. The process-centric simulation is adopted as it is appropriate for the shipyard production system simulation, which is an engineered-to-order industry, and it is easy to implement the concept of dynamic resolution. According to this methodology, we present a simulation application that focuses on the fabrication shop of a shipyard.
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| 3. |
- Shin, Jong Gye, et al.
(författare)
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Model-Based Computational Shipyard Dynamics and Its Applications
- 2020
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Ingår i: Journal of Ship Production and Design. - : The Society of Naval Architects and Marine Engineers (SNAME). - 2158-2866 .- 2158-2874. ; 36:1, s. 87-95
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Tidskriftsartikel (refereegranskat)abstract
- A ship production system can be represented by various production factors and production management indicators. To manage such a system efficiently, a theory is required to analyze and predict its behavior. The theory should be able to fully express the relationships between production factors and production management indicators. For this purpose, computational shipyard dynamics was proposed by Kim et al. in the Journal of Ship Production and Design (2018). This methodology includes input variables, output variables, and key performance indicator (KPI) functionals, implemented as a simulation model. In this study, a rigorous approach to realize a model of a complex ship production system is presented by embodying previous research. A model-based ship production system theory is defined, which consists of production factors, production management indicators, and the relationships between them, called the simulation-based KPI functionals. The production factors are defined using a six-factor model, and the production management indicators are defined using KPIs that are already used in shipyards so that they are quantitatively measurable. To verify the proposed theory, it was applied to fabrication shop, panel block assembly line, and ship block logistics simulation cases, which are examples that are similar to the job shop, flow shop, and project shop cases, respectively.
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| 4. |
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| 5. |
- Jeong, Yongkuk, et al.
(författare)
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An analysis of shipyard spatial arrangement planning problems and a spatial arrangement algorithm considering free space and unplaced block
- 2018
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Ingår i: The International Journal of Advanced Manufacturing Technology. - : Springer Nature. - 0268-3768 .- 1433-3015. ; 95:9-12, s. 4307-4325
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Tidskriftsartikel (refereegranskat)abstract
- The components of shipyard production systems can be classified into products, processes, facilities, space, humans, and schedules. The production capacity of a shipyard may vary depending on how they are operated. Particularly in the case of ships, it is important to efficiently utilize the limited space because they have large blocks, which are semi-finished products made during the shipbuilding process. To efficiently utilize the space, the locations of blocks must be determined taking various factors into consideration when arranging them in the workshop or stock area. This problem can be described as a spatial arrangement problem. However, as the items with fixed arrival dates and departure dates occupy the space for certain periods before being released from shipyards, this problem must be approached from the perspective of a spatial arrangement planning problem for certain periods and not as a simple spatial arrangement problem. In this study, various shipyard spatial arrangement planning problems are classified and defined based on arrangement areas, arrangement items, algorithms, and evaluation factors. In addition, taking the increasing sizes of shipyard blocks into consideration, evaluation factors and algorithms are proposed so that the shape of the free space and the characteristics of unplaced blocks can be considered in the spatial arrangement planning problems of large blocks. The performances of the proposed evaluation factors and algorithms were verified using block data generated by analyzing existing shipyard data product information. The proposed algorithm performed better than the existing algorithm for spatial arrangement planning problems of large blocks. However, the performance of the proposed algorithm was not significantly different from the existing algorithm when the size of the arrangement item was relatively small compared with the arrangement area.
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| 6. |
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| 7. |
- Lee, Dong Kun, et al.
(författare)
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Optimized design of electric propulsion system for small crafts using the differential evolution algorithm
- 2014
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Ingår i: International Journal of Precision Engineering and Manufacturing-Green Technology. - : Korean Society for Precision Engineering. - 2288-6206 .- 2198-0810. ; 1:3, s. 229-240
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Tidskriftsartikel (refereegranskat)abstract
- Given the stricter environmental regulations and rising oil prices, means of transportation based on eco-friendly fuel are drawing increased attention. Electric propulsion systems (EPSs) have been applied to various means of transportation, including cars, and many studies have examined ships equipped with EPSs. Generally, because of the low energy density of the battery, EPS-equipped vehicles experience the disadvantages of limited operating time and distance compared to fossil fuel-based vehicles. In this study, we developed an algorithm that determines the optimal electric motor and battery specifications for the basic requirements of a small craft equipped with an EPS. Moreover, to control the stability of the craft, we developed an algorithm that optimally arranges EPS components, wherein the center of gravity is used as an object function. The differential evolution algorithm was used for optimization, and the effectiveness was verified by applying this algorithm to the actual design of a small craft. The proposed algorithm represents the research results for determining the basic EPS specifications for a small craft and deriving an optimal arrangement for these specifications. This algorithm is expected to be effectively applied to design a new electric propulsion ship or to convert an existing ship to an electric propulsion ship.
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| 8. |
- Lee, Dong Kun, et al.
(författare)
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Simulation-based work plan verification in shipyards
- 2014
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Ingår i: Journal of Ship Production and Design. - : The Society of Naval Architects and Marine Engineers. - 2158-2866 .- 2158-2874. ; 30:2, s. 49-57
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Tidskriftsartikel (refereegranskat)abstract
- The productivity of a shipyard depends on how efficiently and systematically its limited resources are managed and used. Korean shipyards, the most competitive in the world, have developed and operate their own production management systems to attain high productivity, each of which reflects the unique characteristics of a specific company. Recently, research on simulation methods to enhance production management systems has been gaining popularity. Production management based on simulations rejects decision-making based on experience and intuition and values the establishment of improvement methods based on quantitative and concrete data. In this article, simulation is applied to the work plan as part of the production planning in shipyards. To this end, the work planning processes and planning systems are analyzed. Based on this analysis, a simulation model and application system are suggested. By using the results obtained in this study, it is expected that shipyards can construct cycles for establishing, simulating, and analyzing work plans, enabling the establishment of more precise production plans.
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| 9. |
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