• Current Optics and Photonics
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• v.3 no.5
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• pp.429-437
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• 2019

Temperature adaptability is an important metric for evaluating the performance of an optical system. The temperature characteristics of the optical system are closely related to the material and shape of its lens. In this paper, we establish a mathematical model relating the temperature characteristics to the shape and material of the lens. Then a novel assembly structure that can solve the lens constraint and positioning problem is proposed. From those basics, the correctness of the theoretical model and the effectiveness of the assembly structure are verified through simulated analysis of the imaging quality of the optical system, whose operating temperature range is $-60{\sim}100^{\circ}C$.

• Composites Research
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• v.37 no.3
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• pp.190-196
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• 2024

The bipolar plate is a crucial element of the vanadium redox flow battery (VRFB) as it serves as both the electrical conduit and the structural support for the cell within the VRFB stack. Although, the graphite material is primarily used for the bipolar plate due to its excellent electrical conductivity, a significant limitation of performance of the VRFB is present due to high interfacial contact resistance (ICR) arises between the electrode and bipolar plate in the cell stack. This study aims to develop an integrated electrode-bipolar plate assembly that will address the limitations of the ICR. The integrated assembly was constructed using a single carbon felt with thermoplastic and thermoset polymers utilizing hot press method. Experimental results verify that the bipolar plate assembly exhibits reduced area specific resistance (ASR) due to the continuous electrical path. Additionally, from the charge/discharge cell test results, the integrated assembly shows improved cell performance. Therefore, the developed integrated electrode-bipolar plate assembly can serve as a substitute for the conventional bipolar plate and electrode assembly.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.133-149
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• 1997

The major two steps required to design a cellular layout are cell formation and cell layout. Because of the differences between manufacturing and assembly operations, the logic of cell formation and cell layout between an FMS and an FAS is not the same. Since the time for the assembly operations is usualaly relatively short, the transfer time is thus very crucial for the performance of assembly systems. Transfore in a cellular FAS it is more important to eliminate backtracking operations in assembly planning, not to allow intercellular movements in cell formation, and to arrange machines according to assembly sequence in cell layout. This study presents a method for the integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.4
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• pp.63-73
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• 1998

With the success of flexible manufacturing systems(FMSs), flexible assembly systems(FASs) have been developed to automatic factories further. As in a cellular FMS, a celluar FAS is considered as the most flexible and feasible assembly systems configuration. This paper presents a method for the integrated layout design in cellular FASs. Unlike the traditional paper, this paper deals with the formation of cells and the layout of cells for jobs with operation times on different machines. The procedure in this paper consists of two distinct phases. The first phase presents machine arrangement in a double rows flowline. cell formation not to allow intercellular movements, and integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors This phase uses older optimal algorithm. The second phase proposes to balance the system with an objective of reducing the degree of workload deviation in the cells. Simulated annealing method is used to balance the system. This phase also shows the integrated layout design in cellular FASs with the cost less than total cost of the first phase.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.671-672
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• 2009

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.3
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• pp.180-193
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• 2005

This paper deals with a multiobjective process planning problem of flexible assembly systems(FASs). The FAS planning problem addressed in this paper is an integrated one of the assignment of assembly tasks to stations and the determination of assembly routing, while satisfying precedence relations among the tasks and flexibility capacity for each station. In this research, we consider two objectives: minimizing transfer time of the products among stations and absolute deviation of workstation workload(ADWW). We place emphasis on finding a set of diverse near Pareto or true Pareto optimal solutions. To achieve this, we present a new multiobjective coevolutionary algorithm for the integrated problem here, named a multiobjective symbiotic evolutionary algorithm(MOSEA). The structure of the algorithm and the strategies of evolution are devised in this paper to enhance the search ability. Extensive computational experiments are carried out to demonstrate the performance of the proposed algorithm. The experimental results show that the proposed algorithm is a promising method for the integrated and multiobjective problem.

• IE interfaces
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• v.17 no.spc
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• pp.20-27
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• 2004

A flexible assembly system (FAS) is a production system that assembles various parts with many constraints and manufacturing flexibilities. This paper presents a new method for efficiently solving the integrated process planning and scheduling in FAS. The two problems of FAS process planning and scheduling are tightly related with each other. However, in almost all the existing researches on FAS, the two problems have been considered separately. In this research, an endosymbiotic evolutionary algorithm is adopted as methodology in order to solve the two problems simultaneously. This paper shows how to apply an endosymbiotic evolutionary algorithm to solving the integrated problem. Some evolutionary schemes are used in the algorithm to promote population diversity and search efficiency. The experimental results are reported.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.2
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• pp.1-8
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• 2014

The automobile manufacture is a typical integrated assembly production that the numerous parts are committed sequentially to the assembly line. In this type of automobile manufacture, WBS (white body storage) and PBS (paint body storage) are operated to adjust the production sequence and to buffer. Starvation (impossibility of production owing to the insufficient supply) or blocking (impossibility of production owing to the over capacity) could occur in some chance, hence, both storages (WBS, PBS) are integrated as a prevention. This system is called integrated storage. In this paper, we suggest the simulation model of 'WBS-PBS integrated storage' and methodology of operation considering both 'Color grouping' and 'Option leveling.'

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.217-226
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• 2006

To maintain competitiveness in the modern automotive market, it is important to carry out process planning concurrently with new car development processes. Process planners need to make decisions concurrently and collaboratively in order to reduce manufacturing preparation time for developing a new car. Automated generation of a simulation model by using the integrated process plan database can reduce time consumed for carrying out a simulation and allow a consistent model to be used throughout. In this research, we developed a web-based system for concurrent and collaborative process planning and flow analysis for an automotive general assembly using web, database, and simulation technology. A single integrated database is designed to automatically generate simulation models from process plans without having to rework the data. This system enables process planners to evaluate their decisions quickly, considering various factors, and easily share their opinions with others. By using this collaborative system, time and cost put into the assembly process planning can be reduced and the reliability of the process plan would be improved.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.75-84
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• 1997

This paper describes the development of an integrating method for process planning and scheduling activities for block assembly in shipbuilding. A block is composed of several steel plates and steel sections with the predetermined shapes according to the ship design. The parts which constitute the block are manufac- tured by cutting and/or bending operations, which are termed as machining operation in this paper. The machining operation is the first process for block assembly which influences the remaining block assembly processes. Thus process planning and scheduling for machining operation to manufacture parts for block are very important to meet the assembly schedule in the shipyard. An integrating method for process plan- ning and scheduling is developed by introducing the concept of distributed process planning and scheduling composed of initial planning, alternative planning and final planning stages. In initial planning stage, nesting parts information and machining emthods are generated for each steel plate. In alternative plan- ning stage, machine groups are selected and workcenter dispatching information is generated. In final planning stage, cutting sequences are determined. The integrated system is tested by case study. The result shows that the integrated system is more efficient than existing manual planning system.