• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.625-626
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• 2006

Nowadays, the increasing global competition forces manufacturing enterprises to apply new technologies method of their products. To save time and cost in assembly process and to increase the quality of products, it is very important to choose an optimal assembly system. We propose a methodology that generates an optimal assembly system by using the Digital manufacturing.

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.131-135
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• 2009

This paper considers the sequencing of products in car assembly lines. The sequence which minimizes overall utility work in car assembly lines reduce the cycle time and the risk of conveyor stopping. The sequencing problem is solved using Tabu Search. Tabu Search is a heuristic method which can provide a near optimal solution in real time. The performance of proposed technique is compared with existing heuristic methods in terms of solution quality and computation time. Various examples are presented and experimental results are reported to demonstrate the efficiency of the technique.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.38-39
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• 2021

The use of temporary container classrooms has increased in recent years due to the development of the construction industry and renovation or rehabilitation of schools. Therefore, various problems, such as errors during assembling, design and insulation issues, and noise problems, have surfaced during the construction of temporary container classrooms. This study analyzes the causes of assembly errors during the manufacturing and installation processes to improve the quality of temporary container classrooms. Assembly errors are caused by non-level planes and inaccurate cutting during the manufacturing process. In the installation process, poor leveling is a major factor that causes errors during the assembly of temporary container classrooms. These causes result in uneven horizontal or vertical planes and uneven height. To solve these problems, quality improvement measures, such as pin connection, jig, joint coupling, and surface plates are proposed in this study.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.4
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• pp.450-457
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• 2018

The determination of assembly sequence in general mechanical assemblies plays an important role in terms of manufacturing cost, duration and quality. In the production of ships and offshore plants, the consideration of productivity factors and welding deformation is crucial in determining the optimal assembly sequence. In shipbuilding and offshore industries, most assembly sequence planning has been done according to engineers' decisions based on extensive experience. This may result in error-prone planning and sub-optimal sequence, especially when dealing with unfamiliar block assemblies composed of dozens of parts. This paper presents an assembly sequence planning method for block assemblies. The proposed method basically considers geometric characteristics of blocks to determine feasible assembly sequences, as well as assembly process and productivity factors. Then the assembly sequence with minimal welding deformation is selected based on simplified welding distortion analysis. The method is validated using an asymmetric assembly model and the results indicate that it is capable of generating an optimal assembly sequence.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.68-77
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• 2006

Nowadays, the increasing global competition forces automobile manufacturer to increase quality and to reduce the cost and time for manufacturing planning. To solve these problems, automobile manufacturers try to apply digital manufacturing technologies. In this paper, a concept of method for planning the digital assembly system is proposed. Based on the requirements of assembly tasks obtained through product analysis, the function and sequence modeling for assembly process is executed using the IDEF0 and UML model. For implementation of digital assembly system, the selected components are modeled by using 3D CAD tools. According to the system configuration strategy, lots of the alternative solutions for the assembly system are generated. Finally, the optimal assembly system is chosen by the evaluation of the alternative solutions with TOPSIS(Technique for Order Preference by Similarity to Ideal Solution) method. According to proposed procedure, digital laser welding system is implemented in DELMIA.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.125-127
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• 2006

A spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assembly for pressurized water reactors(PWRs). The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral loads acting on the nuclear fuel assembly so as to keep the nuclear fuel assembly straight. To meet this requirement, it is necessary to weld the welding parts carefully and precisely. In this study, weld qualities such as, weld bead size, penetration, spatter, etc. manufactured by various welders were compared and analyzed. Comparison results show that the weld qualities could be improved by selecting the optimal welding condition and also improving the welding technique.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.463-470
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• 2023

In this study, an electronic parts assembly training system using Leap Motion was developed in consideration of the processes actually operated in the assembly process of electronic products. Based on Leap Motion and Oculus VR equipment, the system was developed to transfer user's hand movement data in real time and convert it into hand movement in virtual space so that electronic parts assembly simulation can be performed step by step. Through this, it was confirmed that the user can obtain an experience similar to the actual electronic parts assembly work, prevent errors that may occur during the assembly process, and improve proficiency. It is expected that this thesis will provide directions for the quality improvement and development of various education and training programs for virtual reality-based manufacturing processes.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.293-301
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• 2016

High-quality gene sets are necessary for functional research of genes. Although Perilla is a commonly cultivated oil crop and vegetable crop in Southeast Asia, the quality of its available gene set is insufficient. To construct a high-quality Perilla gene set, we sequenced mRNAs extracted from different tissues of Perilla citriodora, the wild species (2n = 20) of Perilla. To make a high-quality gene set for P. citriodora, we compared the quality of assemblies produced by Velvet and Trinity, the two well-known de novo assemblers, and improved the de novo assembly pipeline by optimizing k-mers and removing redundant sequences. We then selected representative transcripts for loci according to several criteria. The improved assembly yielded a total of 86,396 transcripts and 38,413 representative transcripts. We evaluated the assembled transcripts by comparing them to 638 homologous Arabidopsis genes involved in fatty acid and TAG biosynthesis pathways. High proportions of full-length genes and transcripts in the assembled transcripts matched known genes in other species, indicating that the P. citriodora gene set can be applied in future functional studies. Our study provides a reference P. citriodora gene set for further studies. It will serve as valuable genetic resource to elucidate the molecular basis of various metabolisms.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.269-277
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• 1998

In this study, a traditional concept of sampling inspection plan for the quality assurance system is extended to a consideration of economic aspects in total production system by representing and analyzing the effects between proceding/succeeding production process including inspection. This approach recognizes that the decision to be made at one manufacturing process (or assembly process) determine not only the cost and the average outgoing quality level of that process but also the input parameters of the cost and the incoming quality to the succeeding process. By analyzing the effects of the average incoming and outgoing quality, manufacturing/assembly quality level and sampling inspection plan on the production system, mathematical models and solution technique to minimize the total production cost for a single product manufacturing system with specified average outgoing quality limit (AOQL) are suggested.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.46
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• pp.119-125
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• 1998

In this study, a traditional concept of sampling inspection plan for the quality assurance system is extended to a consideration of economic aspects in total production system by representing and analyzing the effects between proceeding / succeeding production process including inspection. This approach recognizes that the decision to be made at one manufacturing process (or assembly process) determine not only the cost and the average outgoing quality level of that process but also the input parameters of the cost and the incoming quality to the succeeding process. By analyzing the effects of the average incoming and outgoing quality, manufacturing / assembly quality level and sampling inspection plan on the production system, mathematical models and solution technique to minimize the total production cost for a single product manufacturing system with specified average outgoing quality limit(AOQL) are suggested.