• Journal of the Korea Society for Simulation
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• v.25 no.2
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• pp.83-92
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• 2016

Tolerances are defined as the allowable variations in the geometry and positioning of parts in a mechanical assembly for assuring its proper functionality. Tolerance analysis is the activity related to estimating the potential accumulated variation in assemblies. If the estimated variances go out of the specified ranges, it causes the quality problem. Thus, we should adjust the tolerances and this activity is called as tolerance design. In this paper, a case study on the accumulated tolerance analysis and design using Monte Carlo simulation is introduced, which is applied for developing a portable medical device. Using the simulation study, we can improve the assemblability and functionality of the product.

• Journal of Korean Society of Transportation
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• v.30 no.6
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• pp.47-57
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• 2012

The purpose of this study is to propose a supplement to current freight demand model by analyzing factors that influence the generation of empty truck movements in regional and urban realms. To achieve this, we examined the relation between the number of empty truck trips and various generators such as truck attributes, origin type and attributes, destination type and attributes, and commodity type. We structured the ordered logit model using 2011 Korea Transport Database (KTDB) data to analyze the generator characteristic of empty truck movements in regional and urban settings. According to the results, the characteristics of regional and urban empty truck movements differed depending on truck attributes, origin type and attributes, destination type and attributes, and commodity type.

• Korean Journal of Optics and Photonics
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• v.17 no.2
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• pp.149-158
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• 2006

We have analyzed various tolerances of the multi-configurative microscopic system for inspecting the wire-bonding of a reed frame by using the Gaussian bracket method and the equivalent lens method. The tolerances for the curvature and the thickness, which are axial symmetric tolerances, are given by varying the back focal length within a fecal depth under diffraction-limited conditions. Moreover, by using the trial and error method, the axial non-symmetric tolerances for decenter and tilt are established by assigning the 5% variation of MTF(modulation transfer function) at the spatial frequency of 50 lp/mm and at the field angle of 0.7 field. As the tolerances with the most probable distribution are distributed within the range of the decay rate of less than 5% independent of the probability distribution of tolerances, we can achieve completely the desired design performances of the multi-configurative microscopic system by using the various ranges of these tolerances.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.328-333
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• 2020

In this paper, we study the analysis method for the aspherical tolerance of a Korsch telescope using a Q polynomial. It is important to analyze the tolerances for evaluating quality in high-precision fabrication of aspherical reflectors for high-resolution satellites. Thus we express the aspheric surface in terms of a Q polynomial in which each coefficient term is composed independently, and analyze the tolerance of a Korsch telescope. We also analyze the tolerance using Zernike fringe sag, which expresses the shape error of an aspherical mirror. By comparing the two results, we confirm that the Q-polynomial method can be used to analyze an aspherical mirror.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.224.1-224.1
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• 2005

• Korean Journal of Optics and Photonics
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• v.26 no.4
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• pp.209-216
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• 2015

A new method is proposed for optimal management of the fabrication and assembly tolerance of optical systems. The practical utility of the method is shown by applying it to a wide-angle anamorphic IR optical system. In this method the wavefront error of an optical system is expressed in terms of Zernike polynomials, and the sensitivity of the expansion coefficients to the variation of design parameters is analyzed. Based on this sensitivity analysis, the optimal tolerances of the fabrication parameters are determined and the best compensators for the assembly process are selected. By using this method, one can accurately predict with good confidence the best possible performance of a completed optical system in practice.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.128-132
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• 2011

We can acquire the criteria of configuration tolerance on the Kick Motor system, KSLV-I upper stage propulsion system from the analysis results of the initial controllability on the KSLV-I upper stage. Also we can assign configuration tolerances on each subsystem from the configuration tolerance on the Kick Motor system. This article deals with the Kick Motor system configuration tolerance criteria and the results of configuration management on the both ground test models and flight test ones.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.4
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• pp.423-428
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• 2015

To identify locations and causes of interference among parts of an indoor air-conditioning unit, a 3D tolerance analysis was performed and optimized with respect to assembly gaps and the tolerance of each part. The maximum value of the defect rate resulting from the tolerance analysis was found to be 72.6 at the assembly portion of the body and drain. The maximum displacement caused by the thermal deformation during a heating operation was calculated to be approximately 1 mm by using finite element analysis (FEA). Therefore, it is possible that an interference among the assembled parts occurs. The tolerance of the drain was modified by the results of the sensitivity analysis. As a result, the defect rate was greatly reduced to 0.03. Through the FEA results of the indoor air-conditioning unit, it was shown that the improved tolerance of the drain decreased the interference among the assembled parts even though thermal deformation occurs during operation.

• Korean Journal of Optics and Photonics
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• v.14 no.5
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• pp.535-544
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• 2003

The sensitivity analysis of a middle wave infrared optical system with 20: 1 zoom ratio is performed to analyze manufacturing and alignment tolerances, and to establish the alignment logic and the focus control strategy. The characteristics of the sensitivities of Zernike coefficients are investigated to all mechanical displacements and several zoom positions using Code-V Macro. From this result, the tolerances of manufacturing and alignment of the optical system are derived and the effective alignment logic is established. Futhermore, an effective focus control strategy is established to make the system simple and compact.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.92-99
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• 2004

The errors can cause the serious loss of the performance of a precision machine system. In this paper, we proposed the method of allocating the alignment tolerances of the parts and applied this method to get the optimal tolerances of a Confocal Scanning Microscope. In general, tight tolerances are required to maintain the performance of a system, but a high cost of manufacturing and assembling is required to preserve the tight tolerances. The purpose of allocating the optimal tolerances is minimizing the cost while keeping the high performance of the system. In the optimal problem, we maximized the tolerances while maintaining the performance requirements. The Monte Carlo Method, a statistical simulation method, is used in tolerance analysis. Alignment tolerances of optical components of the confocal scanning microscope are optimized to minimize the cost and to maintain the observation performance of the microscope. We can also apply this method to the other precision machine system.