• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.5
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• pp.204-212
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• 2002

In order to improve the reliability of high voltage rotating machines, it is necessary to understand the breakdown mechanism of stator windings. Especially partial discharge(PD) inception and growth are important in stator winding insulation. Recently, many research on the diagnosis of stator winding insulation for large rotating machines have been developed since the 1970s. Capacitive couplers have been the most widely used sensor for on-line partial discharge detection in rotating machines. This paper deals with the electrical on-line monitor characteristics of ceramic coupler(CC) which has been developed to continuously measure the PD activity in operating high voltage motor stator windings on site. We investigated the electrical characteristics(PD quantity, breakdown voltage and frequency response) to develop CC. This paper presents frequency characteristics and laboratory test result to compare conventional 80([F] epoxy-mica coupler(EMC) and 105[pF] CC for PD measurement with 6.6㎸ model stator windings.

• Korean Journal of Human Ecology
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• v.11 no.3
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• pp.307-319
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• 2002

We studied on the development of clothing pressure measurement system for wear comfort of foundations(girdle, brassiere, all-in-one). Measurements of clothing pressure were made on subjects wearing girdles, brassieres, all-in-ones of several type(material, size) using by CPMS(clothing pressure measurement system: Tech-Storm. Co). Wearing experiments have been carried out using nine women in the twenties and six women in the forties. The results obtained are as follows: 1. The clothing pressure applied by girdle was higher in the hard type than the soft type by $5-10gf/cm^2$, also recorded a high clothing pressure at points of waist band line and thigh lateral. 2. Clothing pressure of brassiere with wire was high at the point of underbust line and shoulder strap. Pressure for 40s showed higher than 20s by $6-7gf/cm^2$. 3. The pressures of abdominal part applied by both of girdle and all-in-one were much greater than those of girdle or all-in-one. 4. We demonstrated the adaptability and conformity of the CPMS by inquiring into the clothing pressure of various foundations.

• Journal of the Optical Society of Korea
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• v.10 no.4
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• pp.178-183
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• 2006

An in-line phase-shifting digital holographic microscopy system was constructed by inserting a conventional microscope in the object arm of a Mach-Zehnder interferometer. It was used to measure the three dimensional shape of a micro Fresnel lens. It was also shown that both the lateral and the axial resolutions of the in-line phase-shifting system using a self-calibration algorithm were superior to those of the best off-axis system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.7
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• pp.261-271
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• 1986

This paper describes a method for the state estimation considering current measurement component and detection of the bad data. The state values are estimated by weighted least square method in which measurement vector included bus injection current and line current. The bad data are detected using standardized variable of normal distribution and identified using sensitivity coefficients. When the bad data were occured by the bad measurement values. The results of the application to the model power system reveal the effectiveness of the presented algorithms.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.4
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• pp.29-36
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• 2002

In this paper, a new edge detection method for area images is presented based on the scan-line image segmentation technology. The existing algorithms are lack of precision in its detections due to the noise factors such as depth perception and illumination problems when processing the 3D image into a 2D image. The general process of applying the scan-line method is to extract straight line components to determine the shape of the objects. However, we implement this method to an arc curve for precise detections. the paper proved precise detections that from off line to on line.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.635-640
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• 2016

This paper dealt with the deterioration characteristics and an on-line diagnosis equipment for SPDs (surge protective devices). An accelerated aging test was carried out using a $8/20{\mu}s$ standard lightning impulse current to analyze the changes of electrical characteristics and to propose the diagnostic parameters and the criterion for deterioration of ZnO varistor which is the core component of SPDs. Based on the experimental results, an on-line diagnosis equipment for SPD was fabricated, which can measure the total leakage current, reference and clamping voltage. The leakage current measurement circuit was designed using a low-noise amplifier and a clamp type ZCT. A linear controller, the leakage current measurement part and a HVDC were used in the measurement of reference voltage. The measurement circuit of clamping voltage consisted of a surge generator and a coupling circuit. In a calibration process, measurement error of the prototype equipment was less than 3%.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.69-72
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• 2007

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• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2986-2988
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• 2005

To improve the reliability of power-line communication systems, the measurement and analysis has been proceeded in many power-line channel environments. In spite of the wired channel, power line channel has many multi-paths that are changing with load-variation, line-interconnection, impedance mismatching and so on. We accordingly need an analysis method based on the multi-path channel impulse response. Recently, a method to describe the homogeneous Power-line network has been published[1]. In this paper the modified method that can describe both the homogeneous and non -homogeneous power-line network has presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.264-270
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• 1996

In this paper, a computer automated system has been developed for measuring the focal length of camera lens using the MTF(Modurar Transfer Function) based on the signal processing around a line CCD and autocollimator. An optical Path for the focal length measurement system has been designed around thelight sourec, collimator, camera, mirror and the line CCD. The eyepiece of the collimator is replaced byline CCD, and the mirror is moved along the focal axis by a PC driven step motor. An efficient method has been designed for finding the optimum MTF value for the focal length based on the least squares approach. The developed system is fullycomputer automated: signal transmission to and from the camera, MTF evaluation based on the line CCD, step motor contorl, etc. The developed system has been applied to a practical camera manufacturing process and demonstrated its performance

• Nuclear Engineering and Technology
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• v.37 no.2
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• pp.167-176
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• 2005

We developed the PERUPS system to aid the on-line performance analysis for the turbine cycle of the YongGwang 3 and 4 nuclear power plants. Procedure of measurement validation is included in the performance calculation to obtain heat balance. Precision of on-line performance calculation is increased via practical modifications of standard calculation algorithms based on the PTC (Performance Test Code). The proposed system also provides useful Web-based aids for performance analysis, including performance data management, a graphic viewer for heat balance and turbine expansion lines, and synthesized reports of performance.