• Journal of Ocean Engineering and Technology
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• 제27권5호
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• pp.28-35
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• 2013

In this paper, a research on the composition of the nesting algorithm fitness function is carried out by performing various numerical experiments to inspect how it affects the scrap efficiency, allocation characteristics, and time consumption, targeting the nesting results of ship parts. This paper specifically concentrates on a method to minimize the scrap ratio and efficiently use the well-defined remnants of a raw plate after the nesting process for the remnant nesting. Therefore, experiments for various ship parts are carried out with the weighting factor method, one of the multi-objective optimum design methods. Using various weighting factor sets, the nesting results are evaluated in accordance with the above purposes and compared with each set for each ship part groups. Consequently, it is suggested that the nesting algorithm fitness function should be constructed differently depending on the characteristics of the parts and the needs of the users.

• Journal of Ocean Engineering and Technology
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• 제11권4호
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• pp.239-248
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• 1997

The nesting of parts cut on raw steel plate has been a subject of interest to the shipbuilding industry for many years. "Nesting" is defined operation of layout of the parts on the raw material with minimizing the waste rate. Therefore, it is very important to optimize the cutting area. Since the existing nesting programs are prepared for expensive workstations and the expert, it is needed to develop nesting program for personal computer to improve the technology of small/middle sized shipyards and their productivity. This study involves development and application of appropriate optimization technique to solve the problem of plate nesting. And the appropriate D/B for storing nesting data developed, the function of D/B is introduced in this paper.his paper.

• Journal of Ocean Engineering and Technology
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• 제18권2호
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• pp.77-82
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• 2004

The purpose of this study is to develop a nesting algorithm, using a genetic algorithm to optimize nesting order, and modified No Fit Polygon(NFP) methodology to place parts with the order generated from the previous genetic algorithm. Various genetic algorithm techniques, which have thus far been applied to the Travelling Salesman Problem, were tested. The partially mapped crossover method, the inversion method for mutation, the elitist strategy, and the linear scaling method of fitness value were selected to optimize the nesting order. A modified NFP methodology, with improved searching capability for non-convex polygon, was applied repeatedly to the placement of parts according to the order generated from previous genetic algorithm. Modified NFP, combined with the genetic algorithms that have been proven in TSP, were applied to the nesting problem. For two example cases, the combined nesting algorithm, proposed in this study, shows better results than that from previous studies.

• Proceedings of the Korea Association of Information Systems Conference
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• 한국정보시스템학회 1996년도 추계학술발표회 발표논문집
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• pp.145-155
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• 1996

This paper is to describe the development of nesting software for the materials cutting plan of footwear manufacturing processes. In shoes cutting process, almost of the materials cutting plan is dependent upon worker's experience. Thus, the pattern nesting by worker's experience for materials cutting is different from the real cutting results and also different from the error size of yield in degree of worker's skill. Recently, a few of domestic shoes' makers make use of oversee's nesting software. But the nesting software unfits for the domestic actual circumstances, and is complex to use, and is expensive, and is not to be interfaced with the auto cutting machine. Therefore, we have developed the economic nesting systems that are easier for novice to use and fit for the domestic circumstances, which can syncronize with the development of the auto cutting machine. The system comprises interrelated modules for materials information, nesting simulation, utility. The architecture of system, the functions of each module, and the information processing procedures of each function are discussed.

• Journal of Ocean Engineering and Technology
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• 제26권4호
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• pp.8-14
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• 2012

Two dimensional nesting is a common problem in industries such as the shipbuilding, automotive, clothing, shoe-making, and furniture industries, in which various parts are cut off from stock or packed in a flat space while minimizing waste or unoccupied space. Nesting is known as an NP-complete problem, which has a solution time proportional to the superpolynomial of the input size. It becomes practically impossible to find an optimal solution using algorithmic methods as the number of shapes to nest increases. Therefore, heuristic methods are commonly used to solve nesting problems. This paper presents an expert system that uses a heuristic search method based on an evaluation function for nesting problems, in which parts and stock are represented by pixels. The system is developed in CLIPS, an expert system shell, and is applied to four different kinds of example problems to verify its applicability in practical problems.

• Transactions of the Korean Society of Mechanical Engineers
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• 제18권12호
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• pp.3236-3245
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• 1994

The nesting of two-dimensional patterns onto a given raw sheet has applications in a number industries. It is a common problem often faced by designers in the shipbuilding, garment making, blanking die design, glass and wood industries. This paper presents a multi-stage layout approach for nesting two-dimensional patterns by using artificial intelligence techniques with a relatively short computation time. The raw material with irregular boundaries and internal defects which must be considered in various cases of nesting was also investigated in this study. The proposed nesting approach consists of two stages : initial layout stage and layout improvement stage. The initial layout configuration is achieved by the self-organizing assisted layout(SOAL) algorithm while in the layout improvement stage, the simulated annealing(SA) is adopted for a finer optimization.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.32-35
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• 2001

In sheet metal forming process, it is very important to nest blanks optimally to get a maximum utilization ratio(UR) to reduce waste of material. Optimal Blank Nesting algorithm is developed about single nesting, double nesting, fixed slitting width and free slitting width. This algorithm was applied to various practical blanks which are under production. Then new optimal nesting configuration was obtained and higher UR was achieved by this program in each cases.

• Journal of Korea Society of Industrial Information Systems
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• 제1권1호
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• pp.203-217
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• 1996

This paper is to describe the development of nesting software for the materials cutting plan of footwear manufacturing processes. In shoes cutting process, almost of the materials cutting plan is dependent upon worker's experience. Thus, thepattern nesting by worker's experience for materials cutting is different form the real cutting results and also different form the error size of yield in degree of worker's skill. Recently, a few of domestic shoes' makers make use of oversee's nesting software.But the nesting software unfits for the domestic actual circumstances , and is complex to use , and is expensive , and is not to be interfaced with the auto cutting machine. Therefore , we have developed the economic nesting systems that are easier for novice to use and fit for the domestic circumstances, which can synchronize with the development of the auto cutting machine. The system comprises interrelated modules for materials information, nesting simulation, utility. The architecture of system, the function of each module, and the information processing proceduresof each function are discussed.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 한국산업정보학회 1996년도 추계 학술 발표회 발표논문집
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• pp.145-155
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• 1996

This paper is to describe the development of nesting software for, the materials cutting plan of footware manufacturing processes. In shoes cutting process, almost of the materials cutting plan is dependent upon worker's experience. Thus the pattern nesting by worker's experience for materials cutting is different form the real cutting results and also different from the error size of yield in degree of worker's skill. Recently, a few of domestic shoes makers use of oversee's nesting software. But the nesting software unfits for the domestic actual circumstances, and is complex to use, and is expensive, and is not to be interfaced with the auto cutting machine. Therefore, we have developed the economic nesting systems that are easier for novice to use and fit for the domestic circumstances , which can syncronize with the development of the auto cutting machine. The system comprises interrelated modules for materials information, nesting simulation, utility . The architecture of system, the functions of each module and the information processing procedures of each function are discussed.

• Journal of the Korea Safety Management & Science
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• 제10권4호
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• pp.337-342
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• 2008

This paper investigates the optimal nesting system for a board. A hybrid method is used to search the optimal solution for rectangular nesting problem. This method is composed of heuristic approach algorithm. An engineer's experience of board nesting in which a loss occurred to sheet because of various individual error and diffidence. So, item layout at resource sheet were evaluated in engineering algorithm logic in which specially designed was installed. The nesting system consists of Lisp and Visual Basic. The system was controlled by AutoCAD so as to best item batch path test.