• Journal of the Korean Society of Radiology
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• v.3 no.1
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• pp.11-15
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• 2009

In this study, the basic research verifying possibility of applications as radiology image sensor in Digital Radiography was performed, the radiology image sensor was fabricated using a multi-layer technique to decrease dark current. High efficiency materials in substitution for Amorphous Selenium(a-Se) have been studied as a direct method of imaging detector in Digital Radiography to decrease dark current by using PN junction or Hetero junction already used as solar cell, semiconductor. Particle-In -Binder method is used to fabricate radiology image sensor because it has a lot of advantages such as fabrication convenient, high yield, suitability for large area sensor. But high leakage current is one of main problem in Particle-In -Binder method. To make up for the weak points, multi-layer technique is used, and it is considered that high efficient digital radiation sensor can be fabricated with easy and convenient process. In this study, electrical properties such as leakage current, sensitivity, signal linearity is measured to evaluate multi-layer radiation sensor material.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.81-89
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• 2009

Recently, Guard lamp was divided from electric facilities for general use as dangerous zone of safety management. This paper presents a remote inspection system of guard lamp that can monitor electrical safety factor. Especially, the developed system adopts the measurement algorithm for detecting resistive leakage current($I_{gr}$) flowing based on the phase difference checkable for sensing at a monitor. Also, It was fabricated the repeater for data transmission and the MMI program At this system, we made experiment on stability of resistive leakage current to verify phase comparison detecting algorism.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.75-80
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• 2010

The present study presented the implementation of a remote control/supervision system for guard lamps used in public illumination with little endeavor by far for safe management, which makes possible to supervise the state and to control the functions remotely including electric safety elements. Especially, the developed system adopts the measurement algorithm for detecting resistive leakage current(Igr) flowing based on the phase difference checkable for sensing at a monitor, being allowable for monitoring at MMI and transmitter for data transmittance. To verify reliability about the algorithm to accurately detect Igr leakage current, the laboratory-based functional test was performed.

• Journal of the Korean Magnetics Society
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• v.21 no.1
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• pp.23-31
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• 2011

From among the NDT (nondestructive testing) methods, the MFL (magnetic flux leakage) method is specially suitable for testing pipelines because pipeline has high magnetic permeability. The system applied to MFL method is called the MFL PIG. The previous MFL PIG showed high performance in detecting the metal loss and corrosions. However, MFL PIG is highly unlikely to detect the cracks which occur by exterior-interior pressure difference in pipelines and the shape of crack is long and very narrow. In MFL PIG, the magnetic field is performed axially and there is no changes of cross-sectional area at cracks that the magnetic field passes through. Cracks occur frequently in the pipelines and the risk of the accident from the cracks is higher than that from the metal loss and corrosions. Therefore, the new PIG is needed to be researched and developed for detecting the cracks. The circumferential MFL (CMFL) PIG performs magnetic fields circumferentially and can maximize the magnetic flux leakage at the cracks. In this paper, CMFL PIG is designed and the distribution of the magnetic fields is analyzed by using 3 dimensional nonlinear finite element method (FEM). In CMFL PIG, cracks, standards of NACE, are detectable. To estimate the shape of crack, the leakage of magnetic fields for many kinds of cracks is analyzed and the method is developed by signal processing.

• The Journal of the Acoustical Society of Korea
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• v.10 no.1
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• pp.37-46
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• 1991

The pitch estimation algorithms witch have proposed until now are difficult to detect wide range pitches regardless of age or sex. A little deviation are observed with reference to the center pitch in the distribution diagram of pitches, since pitches are characterized by a physical limitation of the coarticulation mechanism. If the center pitches are refered to the accurate pitch extraction procedure, the algorithms will be not only simplified in procedure but also improved in accuracy. In this paper, we proposed an algorithm that the center pitches are accurately detected by using the spectrum leakage phenomenon for the noise speech signals.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1567-1568
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• 2015

태양광 발전시스템에서 발생되는 누설전류에 인하여 누전화재와 인체감전 등의 전기재해를 방지하기 위해서 직류누전차단기를 개발하였다. 직류누설전류를 측정할 수 있는 센서를 개발하여 (+)전선로와 (-)전선로에 흐르는 누설전류를 각각 검출하는 방법을 제안하였다. 제안된 방법과 개발된 센서를 이용하여 시작품을 제작하고 센서에 대한 감도전류 특성시험을 수행하였다. 또한 인버터가 포함되어 있는 태양광 발전시스템에 적용하여 실제 나타나는 직류누설전류를 측정하는 시험을 수행하였다. 그 결과 직류누설전류센서의 정확성을 확인하였으며, 전선로에 흐르는 직류 및 교류성분의 누설전류를 ${\pm}5%$ 범위 내에서 측정함을 확인하였다. 개발된 센서를 적용한 태양광 발전용 직류누전차단기를 제작하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.67-73
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• 2001

This paper resents a developed measuring device of resistive leakage current and a fundamental discussion of deterioration diagnosis for Zinc Oxide(ZnO) arrester blocks. We have developed the leakage current detection device for ageing test and durability evaluation for ZnO arrester blocks. The resistive leakage current can be used as an indicator to discriminate whether the ZnO arrester blocks is in good state or in bad. The resistive leakage current measuring system with the compensation circuit was designed and fabricated. The sauce tests for ZnO arrester blocks were investigated by observing the resistive leakage current together with fast Fourier transform analysis. The proposed monitoring systems for the resistive leakage current can effectively be used to investigate the electrophysical properties of ZnO arrester blocks in laboratory and to develop the techniques of forecasting the deterioration of ZnO arresters in electric power systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.419-424
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• 2011

The system-on-board detectable and controllable the electrical fires due to ground fault(GF), arc fault and overload is implemented. The system IC for controlling and preventing the electrical fires is available to this system. The GF detection circuit for detecting the electrical leakage current, the arc fault detection circuit and the overload detection circuit controllable the input voltage for flowing the overload current are designed. The GF detection circuit and the arc fault detection circuit are good operated to the electrical leakage current and the arc signal, respectively. It is confirmed that the overload detection circuit has shown no erratic operation with the noise or the load variation and is only operated at the overload condition.

• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.325-331
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• 2005

The magnetic Hut leakage (MFL) type nondestructive testing (NDT) method is widely used to detect corrosion and defects, mechanical deformation of the underground gas pipelines. The object pipeline is magnetically saturated by the magnetic system with permanent magnet and yokes. Because of the strong magnetic field enough to saturate the pipe, there could be distortion of the sensing signals because of the magnetization of the pipeline itself, To detect the defects precisely, the sensing signals are need to be compensated to eliminate the distortions coming from the media hysteresis. In this paper, the magnetizations of the pipeline in MFL type NDT are analyzed by Preisach model and 3D FEM. The distortions of the sensing signals are analyzed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.864-871
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• 2002

Acoustic emission(AE) technique has been applied to not only mechanical property testing but also on-line monitoring of the entire structure or a limit zone only. Although several AE devices have already been developed for on-line monitoring, the price of these systems is very high and it is difficult for the field to apply yet. In this study, we developed a specially designed PC-based leak detection system using A/D board. In this paper, AE technique has been applied to detect leak for heat exchanger by analyzing the characteristics of signal obtained from leak. It was confirmed that the characteristics of the signal generated by the turbulence of gas in the heat exchanger is narrow band signal having between 130-250kHz. Generally, the amplitude of leak signal is increased as the leak size increasing, but showed no significant change at frequency characteristic. Leak source location can be found by determining for the paint of highest signal amplitude by comparing with several fixed sensors. In this paper, AE results are compared with the PC-based leak detection system using A/D board.