• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.55
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• pp.13-24
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• 2000

6 sigma movement is the most prominent quality improvement methodology in practice. Measurement plays an important role in helping any organization improve quality. Therefore, the measurement systems analysis is the first step for the quality improvement of manufacturing process in 6 sigma movement. In this study, we investigate the effect of Gage Repeatability and Reproducibility(Gage R&R) in view of defect rate and process capability indices, and provide guidelines for acceptance of gage repeatability and reproducibility(%R&R) for six sigma quality.

• Journal of Korean Society for Quality Management
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• v.44 no.1
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• pp.77-94
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• 2016

Purpose: This paper reviews Type 1 Gage study, Gage R&R study, and procedure of ISO 22514-7 for assessing a measurement system, and discusses some relationships between the measurement capability indices. Methods: The gage capability index $C_g$ of Type 1 Gage study, precision-to-tolerance ratio PTR of Gage R&R study, and measurement performance ratio $Q_{MS}$ and $Q_{MP}$ of ISO 22514-7 are considered in this paper. Results: This paper derives the relationships between $C_g$ and $Q_{MS}$, PTR and $Q_{MP}$, and $Q_{MS}$ and $Q_{MP}$, respectively, and discusses the acceptance conditions for each procedures. Conclusion: The measurement capability analysis is the first step for the quality improvement of the manufacturing processes. Therefore the result of this study provides a helpful guidelines for assessing the measurement system, enabling proper evaluation of manufacturing processes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.493-498
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• 1993

This paper proposes a high precision measurement technique to obtain the height of gage block. The proposed technique is consisted of two steps : In the first step, laser position transducer and electric micrometer are adopted to obtain a coarse value of the height of gage block, and then, second, heterodyne laser interferometry is adopted to acquire the precision value. The experiment results show that accuract in the order of a few nanometer is achieved for the gage blacks of as high as a few millimeter.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.128-135
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• 1996

This paper proposes a high precision measurement technique to obtain the height of gage block with a few millimeter height. The proposed technique is consisted of two steps : In the first step, laser position transducer and electric micrometer are adopted to obtain a coarse value of the height of gage block, and then, in the second step, heterodyne laser interferometry is adopted to acquire the precision value. A new kind of phase detector is constructed in the low cost for the heterodyne interferometer and its linearity with ${\pm}1%$ is confirmed by experiment. Also measurement error factors due to enviroments are discussed and methodology to reduce such errors is proposed. Preliminary experiments are carried out for the gage blocks of as high as a few millimeter.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.2
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• pp.211-221
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• 1998

It is very important to have a satisfactory measurement system, since it is useless to try to improve the manufacturing process without an adequate measurement system. Therefore, evaluation of the measurement system is the first step for the quality improvement of the manufacturing process. To estimate the measurement error we must conduct a controlled gage repeatability and reproducibility(gage R&R) study. Many manufacturers use a gage or instrument to measure multiple dimensions for the overall quality of the manufactured parts. In this case, it is necessary to estimate the gage R&R for multiple dimensions. When a gage measures a large number of dimensions of a part, it is very time-consuming and costly to measure all the dimensions. In this paper we propose the use of the principal component analysis method to identify a few principal components out of the original multivariate measurement capability to explain most of the measurement system variation pattern.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.104-108
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• 1993

The linear length measurements are most frequently performed and should be most accurate among other parts in dimensional metrology. We developed the linear measuring system using a laser interferometer to improve the accuracy and to shorten the calibration time. The uncertainty of the system is 0.01 .mu. for 500mm steel gage block. The range of the measurement and resolution of the system are 1000mm and 0.01 .mu. m, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.132-140
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• 2000

In conventional drilling, burr geometry can be changed according to the variation of drill geometry like point angle, rake angle. Step drilling is proposed to minimize the burr formation in drilling operation. The burr formed in first cutting can be removed in second cutting by the edge in step. The burr formed in second cutting by the edge in step can be minimized according to the change of geometry like, step angle and depth. The mechanism in step drilling is analyzed. Some step drills are applied to drilling the input shaft which is used for vehicle steering. To measure the burr formed in drilling, laser and height gage are used.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.5
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• pp.329-335
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• 2006

It is necessary to study on the stress concentration experimentally, which is the main reason to avoid mechanical dilapidation and failure, when designing a mechanical structure. Stress concentration factor of a specimen of cantilever beam with a circular hole in the center was measured using both strain gage and photoelastic methods in this paper. In strain-gage measurement, three strain gages along the line near a hole of the specimen were installed and maximum strain was extrapolated from three measurements. In photoelastic measurement, two methods were employed. First, the Babinet-Soleil compensation method was used to measure the maximum strain. Secondly, photoelastic 4-step phase shilling method was applied to observe the strain distribution around the hole. Measurements obtained by different experiments were comparable within the range of experimental error.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.46-51
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• 2002

Cold expansion of fastener holes is a mechanical process widely used in the aerospace industry. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses on the hole surface. The residual stress profile depends on the parameters of cold expansion, which are expanding rate, inserting direction of mandrel, material properties dtc. Despite its importance to aerospace industiries, little attention has been devoted to the accurate modeling of the process. In this paper, three-dimensional finite element simulations have been conducted for the cold expansion in an aluminium plate in order to predict the magnitude and distribution of the residual stress. To prove the results of FE analysis, the residual strain was measured by strain gage in cold expansion test. Maximum compressive residual stress could be increase about 7 percentage using the 2-step cold expansion method.

• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.485-493
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• 2006

This study is to combine precipitation data with different spatial-temporal characteristics using an optimal weighting method. This optimal weighting method is designed for combination of AWS rain gage data and S-band RADAR-estimated rain data with weighting function in inverse proportion to own mean square error for the previous time step. To decide the optimal weight coefficient for optimized precipitation according to different training time, the method has been performed on Changma case with a long spell of rainy hour for the training time from 1 hour to 10 hours. Horizontal field of optimized precipitation tends to be smoothed after 2 hours training time, and then optimized precipitation has a good agreement with synoptic station rainfall assumed as true value. This result suggests that this optimal weighting method can be used for production of high-resolution quantitative precipitation rate using various data sets.