• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.81-86
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• 2012

This paper describes the analysis technique of risk voltage around grounding electrode by new touch and step voltage measurement methods. We have analyzed three techniques for risk voltage measurement, such as footprint-electrode method, test-probe method, and simulated-personnel method. We have selected test-probe method considering applicability of site. In order to reduce error related to the location of the auxiliary electrode, we propose a new approach to perform risk voltage measurement with minimum errors and short auxiliary electrode distances. Field tests were carried out at a grounding grid. It can be concluded that the proposed method will be satisfactory for risk voltage measurement.

• Journal of the Korean Society of Visualization
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• v.10 no.3
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• pp.42-47
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• 2012

Experimental data for the flows in a mixing tank with a bottom agitator are useful for the validation of CFD commercial code. A hybrid volume PIV measurement technique was constructed to measure the flows inside of the mixing tank. The measurement system consists of three cameras. An agitator was installed at the bottom of the tank and it rotates clockwise and counterclockwise. Using the constructed measurement system, instantaneous vector fields were obtained. A phase averaging technique was adopted for the measured instantaneous three-dimensional velocity vector fields. Turbulent properties were evaluated from the instantaneous vector fields.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.476-481
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• 1999

This paper describes a new technique for measurement of the displacement less than one-quarter of the wavelength of ultrasonic wave using ultrasonic pulse-echo method. The technique determines the displacement of a journal bearing from the amplitudes of the total reflected waves from the surface of journal inside the bearing. Vibration of journal bearing can be measured without using a very high frequency ultrasonic transduce over 100MHz which must be used in the conventional techniques for the precision measurement of a small displacement. The method also requires no inversion process to extract the thickness from the waveforms of the reflected waves, so that it makes possible on-line measurement of the vibration of journal bearing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.426-429
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• 1999

In this paper, we have provided the measurement technique of the grounding mesh resistance by field measurements. The standard of measurement is specified in the IEEE Std 81.2-1991 and JEAC 5001-1988, which is the the fall-of-potential method by test-current injection, but this method is difficult to apply at field, where is small around a electric power substation of domestic. For the convenient measurement method, space of assistant probe and quantity of test-current injection are changed step for step. As the result, ' the proposed measurement technique of grounding mesh resistance is that the space of current and potential probes must be fixed at 150rn from a grounding mesh, the test-current injection has to keep 5A or more.

• Smart Media Journal
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• v.4 no.2
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• pp.34-45
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• 2015

The illegal copy of Windows software is one of the problems, because Windows is the most popular operating system in the country. The illegal copy can be infringe a software copyright, and software birthmark is one of solutions which is protecting software copyright. Software birthmark is a technique to distinguish software piracy using feature information from software. The type of software birthmark can be differentiated between static birthmark and dynamic birthmark through an extraction method. Static birthmark and dynamic birthmark have strengths and weaknesses. In this paper, we propose similarity measurement technique using dynamic birthmark based on API, and we explain extraction process of dynamic birthmark. In addition, we have verified that the proposed similarity measurement technique meet resilience and credibility through experiment. Furthermore, we saw that proposed measurement technique better than existing measurement technique.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.215-221
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• 2006

A stereoscopic particle tracking velocimetry (SPTV) technique based on the 2-frame hybrid particle tracking velocimetry (PTV) method was developed. The expansion of 2D PTV to SPTV is facilitated by the fact that the PTV method tracks individual particle centroids. To evaluate the performance and measurement accuracy of the present SPTV technique, it was applied to flow images of rigid body translation and synthetic standard images of jet shear flow and impinging jet flow. The data processing routine and measurement uncertainty of the SPTV technique are compared with those of conventional stereoscopic particle image velecimet.y (SPBV). In addition, the centroid translation effect of 2D particle image velocimetry (PIV) is defined and its effect on SPIV measurements is discussed. Compared to the SPIV method, the SPTV technique has inherited merits of concise and precise velocity evaluation procedures and provides better spatial resolution and measurement accuracy.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.108-120
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• 1996

A new technique and theory are proposed which correct orientation of a cylinder to perform a reliable measurement of the surface profile. We analyze characteristics of machined surfaces, e.g., ground, lapped and turned surfaces. Based upon the results. the optimum correction technique is derived by the statistical method. To verify the techinques, measurements are carried out by using the contact stylus profilometer on a controllable table. The measurement shows that surface information of cylinders can be acquired with high accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.102-108
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• 2004

In this paper, we studied a vibration problem that is critical and common to most precision measurement systems. For micro mechanical part measurements, results obtained from the vision-based precision measurement system may contain errors due to the vibration. In order to defeat this generic problem, for the current study, a PC based image processing technique was used first, to assess the effect of the vibration to the precision measurement and second, to develop an in-situ calibration algorithm that automatically compensate the measurement results in real time. We used a set of stereoscopic CCD cameras to acquire the images for the dimensional measurement and the reference measurement. The mapping function was obtained through the in-situ calibration to compensate the measurement results and the statistical analysis for the actual results is provided in the paper. Based on the current statistical study, it is expected to obtain high precision results for the micro measurement systems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.105-109
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• 1991

A computer aided flatness calibration system has been developed. Rectangular grids based measurement procedure is proposed with closing error technique. giving advantages over conventional diagonal measurement procedures (‘Union Jack’). A new analysis technique has been developed for flatness evaluation called ‘ETT(Enclose Tilt technique)’, enabling minimum separation definition which is acknowledged as standard term for flatness definition. Practical assessment shows the performance of the developed system.

• Journal of ILASS-Korea
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• v.7 no.3
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• pp.24-30
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• 2002

In the analysis of the mass distribution and SMD(Sauter Mean Diameter), planar laser imaging technique is a convenient and useful one when compared to the mechanical pattemator or PDPA (Phase Doppler Particle Analyzer). But recorded signals at cameras and intensity of laser are distorted by attenuation. Using experimental datum and assumptions, we study measurement errors due to attenuation in plannar image technique.