• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.907-910
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• 1992

This paper deals with the mesurement and the analysis by means of EMTP simulation for the fast-rising switching surges. The fast-rising surges having up to 180ns of front time and 3.42 p.u of peak value were measured at the 154KV substations. The fast-rising surges are expected to cause electric breakdown because the penetrating surges to the transformers result in the higher stress in the winding end than the average stress along the winding.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.111-120
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• 1996

In this paper, we proposed an inductance loaded small type open-loop travelling wave antenna model for the suitable VHF/UHF frequency bands moisture measurement systems and analyzed its operating characteristics by galerkin's solution method. This antenna model enables to change the oeprating rsonance frequency from the frequency range 150 Mhz to 1.0 Ghz without changing the antenna design dimensions by only varing the load inductance values and it showed the similar operating charcteristics and narrowband resonance characteristics at each resonance frequencies. Also this model showed the uniformly distriubte dpower radiation characteristics above the loop axis and it can effectively suppress the spurious radiations from its narrowband resonance characteristics.

• The korean journal of orthodontics
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• v.14 no.1
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• pp.127-134
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• 1984

The purpose of the present study was to investigate the correlations of malocclusion between the mother and the offspring and thus heritable features from mother to her offspring. Dental impression was taken of the both jaws of 73 mothers and their sons and 109 mothers and their daughters, and the measurement was obtained from the models. The correlation coefficient of the mesio-distal diameters of teeth and that of occlusion and arch variable was calculated from the mesurement. After the data was analyzed and estimated, the following results were obtained : 1. It was evident that the tooth size of the offspring was influenced from their mother. 2. It was evident that the occlusion, the arch size and shape of the offspring were influenced from their mother. 3. There was not the marked difference between the heredity of occlusion variable and arch variable on the mother-offspring relationship. 4. The correlation of the lower intercanine width and the lower available space discrepancy between the mother and the offspring were greatly influenced with the environmental factor.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.163-165
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• 2009

Automatic Vision Inspection(AVI) systems automatically detect defect features and measure their sizes via camera vision. It is important to predict the performance of an AVI to meet customer's specification in advance. In this paper, we propose a statistical method for prediction of false alarm rate regarding inconsistency of defect size measuremet process. We only need are a simple experimental trial for repeated defect size measurement test. The statistical features from the experiement are utilized in the prediction process. Therefore, the proposed method is swift and easy to implement and use. The experiment shows a close prediction compared to manual inspection results.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.28-31
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• 2010

In order to clarify the characteristics of power performance and uncertainty of a wind turbine, an investigation was performed in Hangyeong wind farm, Jeju island, Korea. Data were collected for 12 months from Feb. 2, 2008 to Jan. 1, 2009. This study was conducted on the base of the International standard, and observed the methods of mesurement and evaluation form IEC 61400-12. As a result, power performance curve was calculated by measured data and compared with the sixth unit of VESTAS V90-3.0MW in Hangyeong wind farms. In consequence of this paper, uncertainty was estimated from 7% to 14% on the range of the average wind speed from 4m/s to 11m/s.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.4
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• pp.504-510
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• 2003

Simultaneous measurements of turbulent velocity and concentration field in a stirred mixer tank are carried out by using PIV/LIF technique. Instantaneous velocity fields are measured with a 1K$\times$1K CCD camera adopting the frame straddle method while the concentration fields are obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by the second pulse of Nd:Yag laser light. Image distortion due to the camera view-angle is compensated by a mapping function. It is found that the general features of the mixing pattern are quite dependent on the local flow characteristics during the rapid decay of mean concentration. However, the small scale mixing seems to be independent on the local turbulent velocity fluctuation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.439-442
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• 2001

The Accuracy of a free-form artifact is affected by machine tool errors, machining process errors, environmental causes and other uncertainty. This paper deals with methodological approach about machine tool errors that are defined the relationship between CMM and OMM inspections of the free-form artifact. In order to analyze the measurement data, Reverse engineering was used. In other words, Surface of Free-Form Artifact is generated by NURBS surface approximation method. Finally, Volumetric error map is made to compare surface of CMM data with that of OMM data.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.145-149
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• 1997

A laser mesurement system, a modified Michelson interferometer,which can accurately measure high speed length and position of servomechanisms by detecting a phase shift in the measurement beam using an optical interference was developed. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. The refractive index of the ambient air was calibrated through the Edlen's formula. The system achieved a resolution of .lambda./40,16nm, a maximum allowable measurement speed of 600 mm/sec, and a length measurement range of 1500mm. Performance of the system was evaluated on the machining center in short and long length measurements

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.227-228
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• 2006

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2005.11a
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• pp.334-339
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• 2005