• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1063-1068
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• 2008

A lens system of a camera module for mobile phones is comprised of the composition and design of various shapes of lens. To improve responses such as the modular transfer function (MTF), a lens system should always be constructed by considering uncertainty that can be caused by manufacturing and assembly error. In this study, tolerance optimization using the Latin Hypercube Sampling (LHS) technique is performed. In order to reduce the computational burden of the tolerance optimization process and decrease the influence from numerical noise effectively, we use the Progressive Quadratic Response Surface Modeling (PQRSM), which is one of Sequential Approximate Optimization (SAO) techniques. Using this method, we achieved optimal tolerance for each lens and obtained reliability for satisfying user‘s requirements. In addition, through the design process the manufacturing and assembly cost of a lens system was reduced.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.439-443
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• 1987

This paper presents a method for constructing model of manufacturing processes for simulation and design of the discrete control logic. The models represent the discrete vent evolution of the system as well as features of the underlying continues processes, for applications such as discrete parts manufacture and assembly, the process is decomposed into operations and for each operation the required resources and associated discrete resource slates are Identified. The structure of the discrete-level control is modeled by modified Perti nets which are synthesized from single resource activity cycles. Construction of nets provides discrete control logic with guaranteed properties based on extended Petri nets theory, for illustration, the proposed method is applied to the high-level discrete control of a two-robotic assembly cell.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2479-2481
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• 2002

중수로 핵연료교환기 램집합체 이상진단시스템 개발과제의 일환으로 램집합체의 시스템 모델링을 수행하고 이를 기초로 램집합제 모형(Mock Up)을 설계 제작하였다. 이를 위해 램집합체 중 B-램의 동적거동에 대해 비선형요소의 영향을 고려하여 시스템에 대한 운동방정식을 유도하였다. 그리고 B-램의 구조를 단순화시킨 모형을 제작하고 이를 검증하기 위해 발전소 현장에서 취득한 램집합체의 운동데이터와 모형의 데이터를 비교 분석하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.131-138
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• 2002

The fuel handling machine handles the core assembly in refueling period of the reactor, it is necessary to predict the motion and structural integrity of it. The kinetic analysis of the fuel handling machine was carried out for the refueling motion. The reaction forces at the joints of machine were calculated with IDEAS code considering the weight of the machine and the loading force of the core assembly, Also, the structural analysis for the machine modeled by lumped-mass and beam elements was performed by using ANSYS code. The stresses and deformations were calculated for the equivalent static force based on the kinetic analysis and the seismic loads. The calculated displacements and stresses are quite low compared with allowable limits.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.149-154
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• 1999

This paper describes a passive safety injection system with free piston Stirling pump working withabundant decay heat in the nuclear reactor during the hypothetical accident. The water column in the tube assembly connected from the hot chamber to the cold chamber in the pump oscillates periodically due to thermal volume changes of non-condensable gas in each chamber. The oscillating pressure in the water column is converted into the pumping power with a suction-and-bleed type valve assembly. In this paper a dynamic model describing the frequency of oscillation and pumping pressure is developed. It was found that the pumping pressure is a function of the temperature difference between the chambers. Also, the frequency oscillation depends on the length of the tube with water column.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.74-80
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• 2020

Crawler-type hydraulic devices facilitate forward and backward driving of construction equipment by converting power into mechanical energy. The existing hydraulic device performance test process is time- and labor-intensive. This study aims to improve efficiency and productivity by automating the hydraulic device production performance test processes, which have been separately conducted so far. We also used SolidWorksⓇ, a 3D modeling program, and ANSYSⓇ, a structural analysis tool, for structural analysis and to verify the suitability of fixing pins required for connecting a hydraulic device to performance test equipment. Our results that employing an automated hydraulic device performance test process improves efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2013-2020
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• 2010

This paper presents a study on the modeling for transparent toaster with a cap of folding type. The toaster was modelled to solve problems of customer's unsatisfaction such as heat loss, input of a piece of dirt, unidentified heating state of sliced toaster. Rapid prototyping was followed by the first modeling, and the second modeling was implemented in order to solve the problems of the first modeling such as interference of holder and door, and the third modeling was developed with a cap of folding type through analysis of assembly and simulation. The 3D modeling tool used in this paper was Pro/Engineer 4.0. The modeling was designed to minimize heat loss and structured with transparent outer case. So the toasting procedure will be identified with the naked eye, and the transparent toaster will improve the customer's aesthetic satisfaction.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.307-314
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• 2012

IFC-based representation method of part library for superstructure module of modular steel bridge is proposed. The library is capable of efficiently offering and exchanging part information in process of manufacture, assembly, design, and construction of modular steel bridge. Entities, representing physical part information in IFC model, are matched semantically with parts of the superstructure module for representation of part information with IFC model. Either types of matched entities are applied in order to verify the role of each part, or new types are defined as a user-defined types. In addition, assembly system has been classified and defined into 4 levels of LoD(Level of Detail) to provide appropriate part information efficiently from the part library in each step of the process. Then, new property is defined for representing the LoD information with IFC Model. Finally, IFC-based test library of modular steel bridge is generated by applying the matched entities and entity types to the actual the superstructure module of modular steel bridge.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.1-12
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• 2016

The industry producing the parts of aircraft engines is a traditional order-made system with highly variety and small quantity, and the manufacturing system is the typical job shop with identical or non-identical multiple machines in a workstation. Furthermore, there are many alternative operations and alternative machines allowed in machining processes, and tremendous routings and assembly operations should be considered. Usually simulation is the most efficient technology to analyze such a complex system, and high modeling skills are required for developing the simulation models. In this paper, a case study on a company which produces the parts of aircraft engines is introduced, specially focused on simulation modeling methodologies for the complex system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.70-75
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• 2006

This paper represents a study on disassembly sequence generation system for automobile parts. This system is practically very useful because proper disassembly sequence of end-of-life product becomes crucial as take-back obligations are imposed for environmental reasons. Therefore a disassembly sequence generation system is suggested to automatically derive all the feasible disassembly sequences from the assembly modeling files. As a result, in consideration of the all parts and subassemblies the optimum disassembly sequence is generated. And the optimum disassembly sequence for a certain part or subassembly can be also suggested.