• Korean Management Science Review
• /
• v.13 no.1
• /
• pp.1-12
• /
• 1996

This paper deals with production scheduling of block assembly shop in shipbuilding company. The Objectives of the schedule are leveling of daily total workload and fair assignment of workload to each department of the shop. Optimizing the objectives, we consider some restrictions which consisit of block due dates, workability of each department, and space restriction. We formulate the problem in mathematical form. But the model is too complex to find the optimal solution (the problem is NP-complete) and we use the genetic algorithm to find a good solution.

• Journal of Ship and Ocean Technology
• /
• v.10 no.2
• /
• pp.37-44
• /
• 2006

The erection in shipbuilding is the process to assemble all the blocks one by one in certain order and requires more leveled and efficient schedule than other processes do. However, erection schedule includes too many constraints to be systemized with simple programs and constraints are changed frequently. These difficulties make it rare to find automatic erection schedule generation system with load leveling ability. In this paper, a CSP (Constraint Satisfaction Problem)-based load leveling algorithm using a maximum load diminution technique is proposed and applied to the block erection scheduling of a dock in a shipyard. The result shows that it performs better than currently used scheduling method based on empirical logics. The maximum load of welding length and crane usage are reduced by 31.63% and 30.00% respectively. The deviation of resource usage amount also decreases by 8.93% and 7.51%.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.1
• /
• pp.162-174
• /
• 2014

Most shipbuilding scheduling research so far has focused on the load level on the dock plan. This is because the dock is the least extendable resource in shipyards, and its overloading is difficult to resolve. However, once dock scheduling is completed, making a plan that makes the best use of the rest of the resources in the shipyard to minimize any additional cost is also important. Block assignment planning is one of the midterm planning tasks; it assigns a block to the facility (factory/shop or surface plate) that will actually manufacture the block according to the block characteristics and current situation of the facility. It is one of the most heavily loaded midterm planning tasks and is carried out manually by experienced workers. In this study, a method of representing the block assignment rules using a diagram was suggested through analysis of the existing manual process. A block allocation program was developed which automated the block assignment process according to the rules represented by the diagram. The planning scenario was validated through a case study that compared the manual assignment and two automated block assignment results.

• Journal of the Society of Naval Architects of Korea
• /
• v.50 no.4
• /
• pp.262-271
• /
• 2013

Owing to the development of mobile communication technology during the last a few years, the number of users of mobile devices such as the smartphone and the tablet PC has increased rapidly. As a result, the range of applications of the mobile devices has also been greatly expanded from an application for the convenience of daily life to an application for assisting the operations of industrial fields. Especially, portability of mobile devices can provide great help in collecting and using information on the production site. In shipbuilding production processes, it is difficult to collect changes of circumstance in the field and reflect the changes to schedule due to the low production automation rate and frequent changes in schedule. In this study, we propose a system to solve the problems of shipbuilding production processes such as the ones described above by using mobile devices. First of all, we organize the production information and production processes of the panel line through the analysis of shipyard panel line operations. Next, we have developed a system that can support the production execution plan of the panel line and monitor the production processes in the field. The system was developed utilizing application virtualization to allow access to the system from various platforms of mobile devices and PC's. The system was implemented using ooCBD methodology considering the future expansion of the system and ease of maintenance.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.2 s.140
• /
• pp.165-174
• /
• 2005

Recently, world leading companies on manufacturing field are trying to adopt a PLM methodology, which is a new production paradigm, for a survival and strengthening the competitiveness. Some projects for a digital shipyard including a methodology of a digital simulation framework are going on by Seoul national university and Samsung heavy industry. A Database methodology for a scheduling data, an interfacing methodology for a simulation input and output, and a synchronized simulation related methodology are required for enhancing the value of the digital simulation for shipbuilding. In this paper, such a methodologies and a related case study for a fabrication factory and an assembly factory are presented.

• Journal of the Society of Naval Architects of Korea
• /
• v.31 no.1
• /
• pp.42-49
• /
• 1994

The purpose of CIM for shipbuilding should be focused on the efficient processing of information among design, process planning and scheduling activities. The most essential technology for shipbuilding CIM is the product model. This model should not only define a physical product "ship" but also a process "ship production". Major activity for ship production is assembly, which requires intensive use of the relationships among parts of ship structure. Other production information are painting area. shape. weight, etc. The fact that major ship structure is "stiffened-plate" type, which allows us to handle the plate thickness as non-geometric information for practical purpose. Therefore. the geometric model for ship product model should handle the relationship among parts(so called topology) efficiently. We find that a face oriented non manifold data structure can meet this requirement. We apply this non-manifold data structure to the ship compartmentation, structural design, and assembly.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2004.05a
• /
• pp.106-110
• /
• 2004

In any large heavy industry like that of ship building, there exist a lot of complications for the arrangement of building blocks optimally for the minimal space consumption. The major problem arises at yard because of laxity in space for arranging the building blocks of ship under construction. A standardized erection sequence diagram is generally available to provide the prioritised erection sequence. This erection sequence diagram serves as the frame work. In order to make a timely erection of the blocks a post plan has to be developed so that the blocks lie in the nearest possible vicinity of the material handling devices while keeping the priority of erection. Therefore, the blocks are arranged in the pre-erection area. This kind of readiness of blocks leads to a very complex problem of space. This arises due to the least available space leading to an urgent need of an availability of intelligent spatial schedule without compromising the rate of production. There exists two critical problems ahead namely, the spatial occupation layout of pre-erection area and the emptying pattern in the spatial vicinity. The block shape is assumed be rectangular. The related input data's are the dates of erection (earliest as well as the latest), geometrical parameters of block available on pre-erection area, slack time and the like.

• Journal of the Society of Naval Architects of Korea
• /
• v.51 no.6
• /
• pp.510-520
• /
• 2014

Unlike other mass production in small variety, shipbuilding process is a project-based method in single variety, which causes unpredictable volatility in the planning system. In shipyards, series of manufacturing processes from fabrication to erection is sequentially carried out. In order to predict unfavorable changes such as overload or low load of working volume, computerized simulation has been being gradually adopted. The data used in the simulation are processed from the database of the main scheduling and planning system. Thus the quality of those data is very crucial for the meaningful results. Unfortunately, research on the verification of data quality is very rare and hardly known to the authors. In this work, using the database of scheduling and product information system of a large domestic shipyard, the data required for the simulation are qualitatively analyzed and verified.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2002.05a
• /
• pp.158-162
• /
• 2002

본 논문에서는 선박의 평블록을 조립하는 공장의 월/주간 일정계획을 수립하는 과정에서 계획의 정도를 향상시키기 위해 시뮬레이션을 적용하는 방안에 대해 다루고 있다. 조선 평블록 조립의 일정계획 수립은 표준 데이터를 근간으로 계획을 수립하므로 일정계획의 정도가 낮을 수 있다. 그리고 공장의 제반 여건 및 운영 방안을 일반적인 일정계획 기법에 반영하여 정도가 높은 일정계획을 수립하는 것은 매우 어려운 일이다. 하지만 시뮬레이션에서는 공장의 제반 여건을 상세하게 묘사 가능하고, 시뮬레이션 수행 후 해당 일정계획의 정도 및 여러 사항에 대해 많은 정보를 얻을 수 있다. 따라서 본 논문에서는 수립된 일정계획에 대해 시뮬레이션을 통해 평가하고, 해당 일정계획의 문제점을 사전에 발견하여 조치함으로써 일정계획의 정도를 한층 높이고자 한다.

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