• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1393-1395
• /
• 2004

Arresters are the best protective device on electrical power systems against transient overvoltages generated by lightning and/or switching operation. Nonetheless, arresters will be deteriorated due to absorption of moisture in the environments of its use, repetition in the protective operation to overvoltages, and some defects at manufacturing. It is therefore important to estimate the electrical characteristic changes of ZnO blocks. In this paper, an accelerated deterioration test by a standard lightning impulse current was carried out to extract parameters needed for diagnosing arrester deterioration, and leakage current components were measured. Total energy applied to the ZnO blocks at each time is 1,050[J] in 8/20[${\mu}s$] impulse current. From the experimental results, we proposed electrical parameters and leakage current level to diagnose arrester soundness.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.12
• /
• pp.2701-2706
• /
• 2009

There are Impulse noise and AWGN in a general image processing. Various methods have been proposed to remove these noises. Well-known filters are Mean, Min-max and Median filter and these show different characteristics depending on the noises. When Impulse noise and AWGN are in superposition environment, single filter doesn't remove noises well. Therefore in this paper, we suggested a switching filter using a probability of noise to restore images in this environment. And we compared a filter with conventional method through simulations.

• Journal of the Korean Ceramic Society
• /
• v.50 no.1
• /
• pp.82-86
• /
• 2013

A poled lead zirconate titanate (PZT) cube specimen is subjected to impulse-type compressive stress with increasing magnitude in parallel to the poling direction at four room and high temperatures. During the ferroelastic domain switching induced by the compressive stress, electric displacement in the poling direction and longitudinal and transverse strains are measured. Using the measured responses, linear material properties, namely, the piezoelectric and elastic compliance coefficients, are evaluated by a graphical method, and the effects of stress and temperature are analyzed. Finally, the dependency of the evaluated linear material properties on relative remnant polarization is analyzed and discussed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2001.11a
• /
• pp.59-64
• /
• 2001

Transient in an electrical system are generated by lightning and switching. This paper presents analysis of switching and lightning surge, and means of limiting the voltage magnification transient for high voltage power systems by using EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor correction banks to harmonic filters. An inductance in series with the power factor correction bank was used to decrease the transient voltage at the customer bus to acceptable levees. The interception of the impulse from the phase wire is fairly straight forward by properly installed surge arresters. The simulation shows that the addition of the surge arrester at the customer location can achieve a substantial reduction of the transient magnitude.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.11a
• /
• pp.106-106
• /
• 2004

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1492-1493
• /
• 2007

This paper represents the development of national standard(NS) for switching impulse(SI) voltage measuring system rated 500 kV. A traceability of the NS to the international standard could be achieved by the intercomparison test with PTB(Physikalisch-Technische Bundesansalt). According to the IEC 60060-2, a measurement uncertainty was assessed. As a result of the tests, the measurement uncertainty and the characteristics of step response were satisfied with the requisite for NS.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.10
• /
• pp.2447-2453
• /
• 2013

The digital images are being degraded by noise in the process of acquisition, storage and transmission, Gaussian or impulse noise is the representative noise. Meanwhile, the image has lots of tendency to be degraded by complex noise, so various researches are being conducted for reducing these complex noise. In this paper, to remove complex noise, the algorithm processed by modified switching median filter and modified adaptive weighted filter according to the result after judging the kinds of noise is proposed. In the simulation result, excellent denoising capabilities. Furthermore, we compared proposed algorithm with existing methods for objective judgement, and PSNR(peak signal to noise ratio) is used by the criterion of judgement.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1774-1777
• /
• 1996

In this paper, applicability of SI-PD(switching impulse - partial discharge) testing method was put on an attempt as a newly proposed diagnostic method for the underground distribution power cable system in Korea. For this purpose, SI-PD testing equipment was designed, and tests were performed using artificial needle-type defects integrated into the 22.9 kV CN/CV cables in drder to prove its reliability. As a result, arc noises, generated from spark gap, were considerably decreased by use of a pneumatic switch immersed into oil, and artificial needle-type defects were well detected with impulse voltage level under $2U_0$. These results imply that it is likely possible to apply SI-PD measurement method as a the nondistructive test for the 22.9 kV CN/CV cable system in Korea.

• Fashion & Textile Research Journal
• /
• v.15 no.3
• /
• pp.381-392
• /
• 2013

This study analyzed the effects of internet fashion consumer characteristics and shopping motivation on price sensitivity as well as the effect of price sensitivity on negative purchasing behavior. A survey was conducted from August 10 to September 20 in 2012 and 364 responses were used in the data analysis. The statistical analysis methods were frequency analysis, factor analysis, reliability analysis, and multiple regression analysis. The characteristics of internet fashion consumers were composed of innovation tendency, impulse buying tendency, information orientation, and variety seeking tendency. Shopping motivation was composed of convenient motivation, social motivation, hedonic motivation, product motivation, and economic motivation. The information orientation and variety seeking tendency of internet fashion consumers influenced the price search. The innovation tendency, impulse buying tendency, and variety seeking tendency of internet fashion consumers influenced the price importance. Convenient motivation, hedonic motivation, and product motivation positively affected the price search; however, social motivation negatively affected the price search. The social motivation, hedonic motivation, and economic motivation of internet fashion consumers positively affected price importance. Price search and price importance influenced the purchasing delay; in addition, price search influenced the switching intention. The results of this study provide useful information for customer management and internet shopping mall marketing strategies.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.21 no.1
• /
• pp.12-18
• /
• 1985

In general the impulse sound sources of underwater generated by electric arc discharge had used static energy of the charged capacitors. The author proposed an underwater arc discharge sound source using secondary voltage of high voltage transformer without capacitors. The arc discharge device was composed of a high voltage transformer and a switching system. The impulse current in the primary turn of the high voltage transformer is controlled by the switching system and inductive current of the secondary turn in the high voltage transformer is used in making impulsive arc discharge. A series of experiment have been carried out to observe the acoustic characteristics of the impulse sound source generated by the arc discharge. The results obtained were as follows: 1. Secondary current at the time of arc discharge keeps after ohm's law in the beginning and the maximum current flows out as soon as arc discharge breaks out. 2. A time difference between a start of applied current and a generation of arc discharge sound is the 3msec and it is generated arc sound when breaking down electric insulation at maximum voltage. 3. The sharper the end of electrodes and the higher the secondary voltage, the higher the sound pressure level. 4. Arc discharge sound was generated even at the distance of 100cm between electrodes and was stably reproductive at the gap of 1cm to 100cm. 5. Electric arc discharge sound wave is a shock wave of pulse-width of 0.15msec and spectral distribution of it is plenty of low frequency components less than 10 KHz.