• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.47-54
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• 2009

In the manufacturing industry, there has been a significant increase in the use of coordinate measuring machines(CMM). In this paper, the sources of CMM measurement performance are discussed. The effects of workpiece position, length and orientation are analyzed by using the design of experiments. Both a fractional factorial design and a factorial design are employed to conduct the experimental study. The analysis of variance is performed to determine the significance of factors in the experiment and regression analysis is applied to make the measurement approximate model. The results show that position along the Z axis, length and orientation affect the CMM measurement performance.

• Journal of Magnetics
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• v.21 no.4
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• pp.529-536
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• 2016

Magnetically suspended sensitive gyroscopes (MSSGs) provide an interesting alternative for achieving precious attitude angular measurement. To effectively reduce the measurement error caused by dynamic imbalance, this paper proposes a novel compensation method based on analysis and modeling of the error for a MSSG. Firstly, the angular velocity measurement principle of the MSSG is described. Then the analytical model of dynamic imbalance error has been established by solving the complex coefficient differential dynamic equations of the rotor. The generation mechanism and changing regularity of the dynamic imbalance error have been revealed. Next, a compensation method is designed to compensate the dynamic imbalance error and improve the measurement accuracy of the MSSG. The common issues caused by dynamic imbalance can be effectively resolved by the proposed method in gyroscopes with a levitating rotor. Comparative simulation results before and after compensation have verified the effectiveness and superiority of the proposed compensation method.

• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.249-256
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• 2013

In accordance with the US Nuclear Regulatory Commission (US NRC), Regulatory Guide 1.20, the reactor vessel internals comprehensive vibration assessment program (RVI CVAP) has been developed for an Advanced Power Reactor 1400 (APR1400). The purpose of the RVI CVAP is to verify the structural integrity of the reactor internals to flow-induced loads prior to commercial operation. The APR1400 RVI CVAP consists of four programs (analysis, measurement, inspection, and assessment). Thoughtful preparation is essential to the measurement program, because data acquisition must be performed only once. The optimized design of a vibration and stress measurement system for the RVI CVAP is essential to verify the integrity of the APR1400 RVI. We successfully designed a vibration and stress measurement system for the APR1400 RVI CVAP based on the design materials, the hydraulic and structural analysis results, and performance tests of transducers in an extreme environment. The measurement system designed in this paper will be utilized for the APR1400 RVI CVAP as part of the first construction project in Korea.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.559-568
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• 1999

This study was conducted to develop the questionnaire for the measurement of environmental attitudes and test its reliability and validity. Development and valiadation of the 46 survey items that measure environmental attitudes were described. The total of 3 surveys were conducted and the total of 510 persons including diverse sample groups were questionnaired. The SAS $PC^+$ package program was used in both the reliability analysis and the validity analysis of surveyed data. Results revealed the very high reliability and the high validity of the questionnaire. The reliability of the finalized questionnaire was increased to the level of Cronbach-$\alpha$ 0.92 after the repeated reliability analyses and revisions of the firstly and secondly designed questionnaires. The validity of our questionnaire was sufficiently affirmed through the use and aplication of factor analysis and known-groups technique.

• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.76-93
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• 1992

The purpose of this study, by surveying the status of firms, measurement-related investment and the defect rate, is to analyze the effect of measurement-related investment and to propose a scheme of efficient measurement-related investment which reduces the defect rate. For this project we obtain the data of the status of the measurement-related investment and the defect rate of 928 firms in Korean manufacturing industry by mailing survey. One of our results shows that the firms which have measurement standard laboratory, i.e, which invest in measurement-related area comparatively high, have the defect rate about 0.8% lower than those firms which don't have measurement standard laboratory. Also we find that the small-and-middle size firms have worse measurement-related facility than the large firms and the firms in the heavy-chemical industry have higher measurement-related investment effect than the firms in the light industry.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.531-537
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• 2014

Through-silicon vias (TSVs) are fine, deep holes fabricated for connecting vertically stacked wafers during three-dimensional packaging of semiconductors. Measurement of the TSV geometry is very important because TSVs that are not manufactured as designed can cause many problems, and measuring the critical dimension (CD) of TSVs becomes more and more important, along with depth measurement. Applying white-light scanning interferometry to TSV measurement, especially the bottom CD measurement, is difficult due to the attenuation of light around the edge of the bottom of the hole when using a low numerical aperture. In this paper we propose and demonstrate four bottom CD measurement methods for TSVs: the cross section method, profile analysis method, tomographic image analysis method, and the two-dimensional Gaussian fitting method. To verify and demonstrate these methods, a practical TSV sample with a high aspect ratio of 11.2 is prepared and tested. The results from the proposed measurement methods using white-light scanning interferometry are compared to results from scanning electron microscope (SEM) measurements. The accuracy is highest for the cross section method, with an error of 3.5%, while a relative repeatability of 3.2% is achieved by the two-dimensional Gaussian fitting method.

• Journal of the Korean Society of Costume
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• v.55 no.3 s.93
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• pp.69-80
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• 2005

The anatomical structure of the head and face are influenced by environmental factors. Therefore in this study we had undertaken to determine normal values of the head and face by 3D measurement in the 384 normal Korean male adults to find out craniofacial characteristics of Korean male adults by the age group. From the basic statistical data analysis, vertex-tragion and the length between the pupils were the longest in their twenties and grew shorter in elderly groups. According to the analysis of the craniofacial proportion, the head type of Korean male adults was short-headed. The statistically noticeable differences were found in the measurement of the left and the right sides of face in the age groups of 20, 30, 40, and 50. The results of the factor analysis of the age group showed two groups which were classified to 20, 40, 50 ages and 30, 60 ages. The order of factor analysis was as follows; the perpendicular length, the horizontal length, and the width (from highest).

• Transactions of Materials Processing
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• v.8 no.3
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• pp.294-305
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• 1999

A vision-based surface-strain measurement system has been still improved since the authors devel-oped the first version of it. New algorithms for the subpixel measurement and surface smoothing are introduced to improve the accuracy and precision in the present study. The effects of these algorithms are investigated by error analysis. And the equations required to calculate 3D surface-strain of a shell element are derived from the shape function of a linear solid finite-element. The influences of external factors on the measurement error are also examined, and several trials are made to obtain possible optimal condition which may minimize the error.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.436-437
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• 2005

3-dimension object's feature measurement is used several industrial field to produce for examination of demanded high quality products by using optical measurement method. 3-dimension object's feature measurement is separated surface scanning and surface non-scanning. In this research, we illuminated interfero-pattern to object, it was constructed with Michelson interferometer by using laser is one of surface non-scanning method. And we extracted phase-map, it is one of featural measurement analysis of 3-dimensional object by using a phase shifting theory.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.260-262
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• 2017

During the construction of the project, all surveying and mapping work is collectively referred to as engineering survey. Therefore, the measurement work contains a wide range of content, in the engineering survey, design and construction management stage are involved. To the actual work, the project measurement runs through the project building in a number of stages, and provide basic services. This paper mainly through the analysis of engineering measurement at all stages of the role played by the measurement work in the project management work to do the following description.