• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.104-111
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• 2003

Micro force measurement is required more frequently for a precision manufacturing and investment in fields of precision industries such as semiconductor, chemistry and biology, and so forth. Null balance method has been introduced as an alternative of a loadcell. Loadcells have advantages in aspects of low cost and easy manufacturing, but have also the limitation in resolution and sensitivity to environment variations. In this paper, null balance method is explained and the dominant parameters related to system performances are mentioned. Null position sensor, electromagnetic system and controller are investigated. Also, the characteristic experiment is carried out in order to estimate the resolution and the measurement range. In order to overcome the limitation by the drift of position sensor and the performance of controller, double electromagnetic force compensation method is proposed and experimented. After controlling and filtering, the resolution under $\pm$ 1mg and measurement range over 300g could be obtained.

• Transactions of Materials Processing
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• v.5 no.4
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• pp.343-352
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• 1996

One of the preferred methods that can be used to verify the results of finite element analysis is to measure surface strains of the deformed part for purpose of direct comparison with simulation results. Instead of using the usual manual method the vision-based measurement method is capable of determining surface geometry and strain from the deformed grid pattern automatically with the help of a computer. To obtain strain distribution over an area, the coordinates of such a surface grid are determined from the multiple video images by applying the photogrammetry principle. Methods to improve the overall accuracy of the vision-based strain measurement system are explored and the possible accuracies that can be attained by such a measurement method are discussed. A major emphasis is placed on the initial grid application method its accuracy and ease of subsequent image processing. Finite element analyses of limiting dome height(LDH) test are carried out and the results of them are compared with exsperimen-tal data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1434-1437
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• 2011

Precision measurement of silicon wafer resistivity has been using single-configuration Four-Point Probe(FPP) method. This FPP method have to applying sample size, shape and thickness correction factor for a probe pin spacing to precision measurement of silicon wafer. The deference for resistivity measurement values applied correction factor and not applied correction factor was about 1.0 % deviation. The sample size, shape and thickness correction factor for a probe pin spacing have an effects on precision measurement for resistivity of silicon wafer.

• 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.

• Implantology
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• v.22 no.4
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• pp.210-218
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• 2018

Purpose: The purpose of this study was to investigate the validity and reproducibility of a method based on cone-beam computed tomography (CBCT) technology for the visualization and measurement of gingival soft-tissue dimensions. Material and Methods: A total of 66 selected points in soft-tissue of the ex vivo head of an adult pig were investigated in this study. For the measurement of radiographic thickness (RT), wet soft-tissue surfaces were lightly covered with barium sulfate powder using a powder spray. CBCT was taken and DICOM files were assessed for soft-tissue thickness measurement at reference points. A periodontal probe and a rubber stop were used for the measurement of trans-gingival probing thickness (TPT). After flap elevation, actual thickness of soft-tissue (actual thickness, AT) was measured. Correlation analysis and intraclass correlation coefficients analysis (ICC) were performed for AT, TPT, and RT. Results: All variables were distributed normally. Strong significant correlations of AT with RT and TPT values were found. The two ICC values between TPT vs. AT and RT vs. AT differed significantly. Conclusion: Our results indicated that correlation of RT was stronger than that of TPT with AT. We concluded that soft tissue measurement with CBCT could be a reliable method, compared to the trans-gingival probing measurement method.

• The KSFM Journal of Fluid Machinery
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• v.3 no.3 s.8
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• pp.25-30
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• 2000

Thermodynamic method of pump performance measurement calculates pump efficiency and flowrate by measuring fluid temperature increase and pressure rise through the pump. The theory of this method is investigated and precise comparison experiment with classical hydraulic method was conducted to verify the accuracy. Classical hydraulic pump performance measurement results and Yatesmeter results based on the thermodynamic method showed good agreement in measured performance.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1022-1027
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• 2004

In this paper, an embedded foot pressure measurement system is proposed to measure foot pressure based on the embedded Linux system. To measure foot pressure data and to evaluate foot pressure distribution for the different insoles, FSR sensor, A/D converter, iPAQ PDA, and a time division measurement method are employed in the system. Utilizing this system, the foot pressure analysis has been performed for the different four shoes. The number of foot pressure/voltage conversion circuits are drastically decreased by the proposed time division measurement method from 406 to 14. The experimental results for the sandal, slipper, oxford shoes and sneakers demonstrate that the proposed system successfully performs the foot pressure measurement.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.12
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• pp.585-587
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• 2005

In this paper, We studied two methods to measure optical characteristics of an electrodeless light source using the integrating sphere(diameter 1.5m). One is to use a center measurement method and the other is to use a side measurement method. As a result of analysis, a side measurement methode without auxiliary lamp is almost similar against a center measurement with auxiliary lamp to reduce a measurement of an error for luminous flux, luminous efficacy and spectral distribution etc. Therefore, Sample which cannot measured by reason of big size and heavy weight can be measured by a side measurement method.

• 보존과학연구
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• s.20
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• pp.49-64
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• 1999

According to damage of papers by the chemical cause, papers become to acidify. Among the 3 kinds of method measuring the acidity of paper, one was nondestructive method measuring the surface of the paper by flat type electrode and the others were destructive methods measuring directly by cold water extract method and hot water extract method. In case of the cellulolytic cultural properties, the latter methods were not applied because those methods must bedissociated papers. To measure the paper acidity nondestructively, we investigated the correlation of the nondestructive method and the destructive methods. The conclusions are as follows. 1) In the relationship of the cold water extract method and the hot water extract method, It was indicated that the pH measured by the hot water extract method was high quality printing paper 0.08, rough printing paper 0.13, and Korean paper 0.29 higher than that by the cold water extract method.2) In the relationship of the cold water extract method and the surface measurement method, It showed that the pH value measured by the cold water extract method was high quality printing paper 1.86, rough printing paper 0.80,and Korean paper 0.58 higher than value that by the surface measurement.3) In the relationship of the hot water extract method and the surface measurement method, It showed that the pH value measured by the hot ABSTRACT water extract method was high quality printing paper 1.78, rough printing paper 0.66, and Korean paper 0.29 higher than that by the surface measurement. From the above-mentioned results, the pH value measured by the surface measurement was need to high about 1.78∼1.86 in high quality printing paper, 0.66-0.80 in rough printing paper, and 0.29∼0.58 in Korean paper and the surface measurement with flat type electrode was very available to measure the acidity of Korean papers actually.

• Journal of KSNVE
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• v.11 no.1
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• pp.57-67
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• 2001

Proposed in this paper is a method of measurement of the flow rate in a pipe. The sound waves which are propagated within a pipe are characterized by that the wavenumber in the axial direction is changed according to the flow rate, and these characteristics are used in the present method of measurement of the flow rate. The amount of change in wavenumber of sound waves according to the flow rate can be obtained from the relationship among acoustic pressure signals within a pipe, which are measured by using a microphone array. The flow rate can be obtained by using the amount of change in wavenumber of sound waves and the relational equation of the flow rate. With respect to errors that can occur during the measurement of the flow rate, the types of errors and the method of correction of those errors are presented. This method of measurement of the flow rate has application limitation conditions due to the sensor interval, assumption of sound waves as plane waves, etc. The numerical simulation and experiments for measuring the flow rate of air in a pipe are performed in order to verify the applicability of this method of measurement of the flow rate. The experimental results are shown to be similar to those of the numerical simulation. And the flow rate measured is shown to be consistent with the actual value within 5% error bound.