• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.205.1-205.1
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• 2011

This study concerns a low head and kaplan turbine efficiency measurement using the acoustic scintillation flow meter(ASFM). The ASFM is one of absolute discharge measurement methods because it measures velocity-area of discharge with couples of transducers. This study shows that the highest efficiency of turbine is 87.7% and the efficiency is 85.8% in the rated output(600kW). The test result is reliable because the efficiency trend from this test is similar to the result of index test conducted in 1986. In this paper, the principle, measurement methods, application and test procedures of the test are discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1176-1181
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• 2010

This paper proposes three positioning algorithms using TOA measurements: 1) The well-known linearization method using Taylor series, 2) a modified Savarese method considering measurement noise, which does not need linearization, and 3) a modified Bancroft method where TOA measurements instead of pseudorange measurements are considered. Furthermore, through an error analysis, for Savarese method, divergence of altitude is anticipated if the transmitters are located at the same height. To prevent height divergence, the Savarese method is modified again for receivers which assumed moving on the even plane. Error analysis also shows the relationship between Bancroft and Savarese method. From the analysis it is expected that the performance of Savarese method is worse than Bancroft method because of error amplification during difference operation. Experiments using real TOA measurement from the time difference of ultra sound and RF validate the proposed methods and show that analysis is correct.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1362-1365
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• 2008

ED-2523 (Measuring methods for matr ix reflective LCD modules) was published by JEITA (Japan Electronics and Information Technology Industries Association) in 2001. Since then, round robin tests had been done and the accuracy of measurement values had been discussed. In this paper, considerations for error factors in four measurement systems are showed.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.253-254
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• 2002

The determination of thrust is very important in hypersonic air-breathing propulsion design and evaluation. Because of the short flow-residence time in the combustor, the evaluation of engine performance is strongly influenced upon the engine thrust. Conventional methods to determine the thrust is using thrust stand or force measurement system. However, these methods cannot be applied to the case where thrust stands are impractical, such as free jet testing of engines, and model combustor. With this reason, the thrust determination method from measured pilot pressure is considered and evaluated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.496-501
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• 2015

In this study, calibration procedure of power assembly tools is suggested and methods are developed for calculating measurement uncertainty. Fist of all, the calibration of joint simulator bench (JSB) was carried out for maintaining traceability and the uncertainty components of JSB were analyzed. The influences of tool speed, tolerance, temperature and length of the adapter were examined by the torque measurement values through experiments. From this research, credibility for calibration results could be enhanced. This experimental results, being used as an effective tool for calibration of power assembly tools, will provide and improve the accuracy of the use of the power assembly tools.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.178-182
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• 2007

This study represents the efficient depth measurement for 3-dimensional microsystems using the disparity histogram from stereo images. Implementation of user-friendly Windows program written in C++ involves the various methods for the stereo-image processing in which the minimization of matching-pixel error upon the unique point for stereo images was carried out as a pre-processing method. Even though MPC among various methods was adopted in the present measurement, the resulting measurements seem to require optimizations of the windows sizes and corrections of post-manipulation for stereo images. The present work using Windows program is promising to measure the 3-dimensional depth of micro-system efficiently in implementing the 3-dimensional structure of micro-systems.

• Journal of Mechanical Science and Technology
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• v.19 no.5
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• pp.1131-1137
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• 2005

Methods for measuring surface roughness based on light reflectivity have advantages over methods based on light interference or diffraction, especially in in-situ, on-the-machine and in-process applications. However, measurement inconsistencies caused by changes in the specimen are still a drawback for field applications. In this study, we propose a new feedback-based algorithm to enhance the consistency against changes in the specimen. The algorithm is deduced from simulations based on light reflectance theory with typical modeled surfaces. The proposed method is similar to a digital controller and regulates the power of reflected light. Experiments varying heights and materials, verified the improvements in robustness of the method against measurement disturbances caused by specimen changes.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.124-124
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• 1999

An ultrasonic method is developed for the measurement of the two-phase mixture level in the reactor vessel or steam generator. The ultrasonic method is selected among the several non¬nuelear two-phase mixture level measurement methods through two steps of selection procedure. A commercial ultrasonic level measurement method is modified for application into the high temperature, pressure, and other conditions. The calculation method of the ultrasonic velocity is modified to consider the medium as the homogeneous mixture of air and steam. and to be applied into the high temperature and pressure conditions. The cross-correlation technique is adopted as a detection method to reduce the effects of the attenuation and the dif.JUsed reflection caused by suface fluctuation. The waveguides are developed to reduce the loss of echo and to remove the effects of obstructs. The present experimental study shows that the developed ultrasonic method measures the two-phase mixture level more accurately than the conventional methods do.

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.16-19
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• 2016

More efficient use of the battery pack is dependent upon how to measure the remaining capacity of the battery accurately. Among various measurement methods, the basic correction measurement method has still been a hot research topic area to reduce the errors. In this paper, the problems of the existing methods have been investigated and the research direction for measuring more accurate remaining capacity has been suggested by applying the numerical simulations in the future.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.376-380
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• 2006

There are several methods which estimate the behavior of the Structures. Recently, several displacement measuring instruments such a GPS are substantially developed. So, considering this technique, displacement measurement will be a very efficient method for estimating the behavior of the Structures and maintenance. Therefore we need to develop methods of structure maintenance & management by using displacement measuring instruments. In this study, I suggest to maintenance & management method by using displacements about simple beams and cantilever beams which are very important structure in civil engineering. The results show that the proposed method is capable of estimating the displacement and stress of the Beam Member by combining the proper number of measurement and optimum measurement points.