• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.597-599
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• 2006

In this paper, we propose an artificial intelligence method to compensate the nonlinearity error which occurs in the heterodyne laser interferometer. Some superior properties such as long measurement range, ultra-precise resolution and various system set-up lead the laser interferometer to be a practical displacement measurement apparatus in various industry and research area. In ultra-precise measurement such as nanometer or subnanometer scale, however, the accuracy is limited by the nonlinearity error caused by the optical parts. The feedforward neural network trained by back-propagation with a capacitive sensor as a reference signal minimizes the nonlinearity error and we demonstrate the effectiveness of our proppsed algorithm through some experimental results.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.766-768
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• 1998

Optical Temperature Distribution measurement System (OTDS) is completely different from conventional electric point sensor in that it uses the optical fiber itself as the sensor. This new concept in temperature measuring system requires only one fiber to be laid. The use of optical fiber also gives the advantage of small diameter, light weight, explosion resistance, and electromagnetic noise resistance. The OTDS is a sensor which is capable of making a precise measurement over a wide range of areas using only a single optical fiber. Since current temperature sensors, such as the thermocouple, are only used to measure temperaturea of point, they are almost impractical for measuring a wider range because of the extremely high cost. In comparision with current sensors, the optical fiber distributed temperature sensor can make much quicker and more precise measurements at a comparatively low cost.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.146-147
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• 2007

A universal four-point contact measurement method, has an advantage of non-existence of contact resistance, is demonstrated by the experiments with carbon nanotubes and ZnO nanowire. Ti/Au and Pt are tried to compare the influence of contact resistance between two different metals. These metals are selected to make Ohmic contact and Schottky contact originated from their different work functions. For precise experiments, Ti/Au and Pt are separately evaporated to form double 'four-point contact electrodes' on CNTs or ZnO, and the voltage-current characteristics are measured. This method can be applied to universal resistivity measurement for nanotubes and nanowires.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.9
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• pp.892-899
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• 2013

This paper discusses difficulties in precise measurements of the scattering parameters in (sub-)millimeter-wave range and tips for more accurate measurements, and provides measurement examples in the G-band(140~220 GHz). First, one investigates the differences in operating principles of scattering parameters measurement systems used in microwave and (sub-)millimeter-wave ranges and describes tips for better operation of the (sub-)millimeter-wave scattering parameters measurement system. In addition, one describes tips for better transmission properties and connection repeatability of waveguides and a precise measurement method for devices with small reflection coefficients.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.3
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• pp.243-253
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• 2002

These days, the application range of digital photogrammetry is being extended actively, so the great variety of research is being progressed about improvement of measurement accuracy. This method can acquisite a high analysis accuracy and can acquisite easily image. But, So this method require a much processing time and effort by increasing a data amount, as the automation of processing must be completed for efficiency improvement of processing. In this study, the automation of image processing stage is established for multi-image aquisition and analysis about a radio telescope. Also, the precise measurement and the accuracy on object were intended to be improved. As a result of this study, the accuracy on the object which demands precise measurement was enhanced from multi image analysis, and also the assembly accuracy of the object could be checked by precise measurement and curve fitting.

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.40.2-40.2
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• 2004

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.23-27
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• 1999

The measurement of thr high-temperature strains is one of the challenging subjects in mechanical engineering. For the precise measurement, proper high-temperature strain gauge, cement and skilled technique are needed. In this paper, a high-temperature strain measurement is performed for the perfectly flat CRT. As this CRT is structurally very weak, cracking of the panel frequently occurs during the heat cycle in the furnace. From the measured strain variations of the panel with tension shadow mask, the crack behavior can be explained.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.199-200
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• 2000

Measurement of low cell gap and retardation by using a rotating polarizer method was proposed. For more precise calculation and measurement, we applied a retardation film that has large retardation value of $1\;{\mu}m$ to measurement system. From experiments, we proved that cell gap and retardation could be measured even though the values of those are so small.

• 한국기계연구소 소보
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• s.19
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• pp.69-79
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• 1989

Cutting tool life monitoring is a critical element needed for designing unmanned machining systems. This paper describes a tool wear measurement system using computer vision which repeatedly measures flank and crater wear of a single point cutting tool. This direct tool wear measurement method is based on an interactive procedure utilizing a image processor and multi-vision sensors. A measurement software calcultes 7 parameters to characterize flank and crater wear. Performance test revealed that the computer vision technique provides precise, absolute tool-wear quantification and reduces human maesurement errors.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.158-162
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• 2000

Measurement of low cell gap and retardation by using a rotating polarizer method was proposed. For more precise calculation and measurement, we applied a simple numerical calculation and a retardation film that has large retardation value of 1 ~m to measurement system. From experiments, we proved that cell gap and retardation could be measured even though the values of those are so small. small.