• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1659-1661
• /
• 2003

Recently, diagnostic techniques have been investigated to defect a partial discharge in high voltage electrical equipment. We have studied the characteristics of the acoustic partial discharge originating from the electrical defects in cubicle GIS(C-GIS). An acoustic emission(AE) sensor is used on the enclosure to detect partial discharge source because the sensor is sensitive to stress waves in its frequency range that may not be from a partial discharge source. AE signal is analyzed with phase-magnitude-frequency number(${\Phi}$-V-n) and pulse per second(PPS). Experience result has shown that the omitted acoustic signal has phase dependency and phase shift characteristic according to increase with applied voltage. These result will be helpful to the pattern recognition of the acoustic partial discharge in a C-GIS.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2003.11a
• /
• pp.111-116
• /
• 2003

Recently, power-electronics equipments or machine that microprocessor is included and computers have been installed continuously in industrial process or region of electronics customer. So concern for power quality, especially sags has been increased. Because those equipments are very sensitive to sags. The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag, it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in oder to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on mitigation-device interface method, especially FCL that is Fault Current Limiter.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.3
• /
• pp.288-293
• /
• 2016

Electronic Image Stabilization(EIS) is widely used as a technique for correcting a shake of an image. The case requiring the EIS function has been increased in high magnification thermal image observation on portable military equipment. Projection Algorithm(PA) for EIS is easy to implement but its performance is sensitive to the projection area. Especially, projection profiles of thermal image have very modest change and are difficult to extract image shifts between frames. In this paper, we proposed algorithm to extract a feature image for the thermal image and compared Block Matching Algorithm(BMA) with PA using our proposed feature image. When using our proposed feature image, BMA was simply implemented using FPGA's internal small memory. And we were able to obtain 30 % PSNR improved results compared to PA.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.9
• /
• pp.699-706
• /
• 2016

Assay of biomolecules based on absorption spectroscopy is a sensitive, minute, quantitative, rapid and real-time process. UV-vis spectrometry has inherent advantages for use in analytical applications. To reduce the consumption of scarce samples, a new generation of miniaturized UV-vis spectrometric systems has been developed. This study determined empirically and through simulations the feasibility of assaying biomolecules by means of UV-vis spectrometry. This paper also reports a fully integrated portable micro-detection equipment system that utilizes a micro-optical path for analysis of micro-volume samples.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.10
• /
• pp.968-975
• /
• 2010

The high interest for the ground vibrations which is caused by the train service is risen. When the trains are passed, a serious force is applied to ground and the caused vibration is propagated to the area of the building by the ground and rocks. This vibration comes to feel in the residents with the direct vibration, it is radiated in sound. The caused vibration and radiated sound affect the human's life, and this vibration brings about the operation interruption of the equipment which is sensitive to the vibration, or will bring about the structural damage of the building. In this study, the effect of the vibrations caused by the passing trains on the railway station and buildings is investigated by vibration measurement. Indoor and outdoor measurement is carried out by each trains.

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.1
• /
• pp.11-16
• /
• 2011

When the trains are passed the station, a serious force is applied to ground and the caused vibration is propagated to the area of the station by the ground and rocks. The caused vibration brings about the operation interruption of the equipment which is sensitive to the vibration, or will bring about the structural damage of the station. In this study, to investigate the vibrational evaluation of railway station by the train service, the vibration simulation was performed and analyzed the effect of the vibration isolating countermeasure. From the vibration measurement, all trains that passed through the station exceeded the vibration criteria. Therefore, the vibration isolating countermeasure was established and the vibration simulation was performed.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2005.09a
• /
• pp.124-128
• /
• 2005

To produce a highly sensitive uncooled microbolometer, the development of a high-performance thermometric material is essential. In this work, amorphous vanadium-tungsten oxide was developed as a thermometric material at a low temperature of $300^{\circ}C$, and the microbolometer, coupled with the material, was designed and fabricated using surface micromachining technology. The vanadium-tungsten oxide showed good properties for application to the microbolometer, Such as a high temperature coefficient of resistance of over -4.0 $\%$/K and good compatibility with the surface micromachining and integrated circuit fabrication process due to its low fabrication temperature. As a result, the uncooled microbolometer could be fabricated with high detectivity over $1.0\;{\times}\;10^9\;cmHz^{1/2}/W$ at a bias current of $7.5\;{\mu}A$ and a chopper frequency of 10-20 Hz

• Steel and Composite Structures
• /
• v.39 no.3
• /
• pp.229-241
• /
• 2021

This work focused on aluminum foam sandwich (AFS) with different foam core densities and different face-sheet thicknesses subjected to constant amplitude three-point bending cyclic loading to study its fatigue performance. The experiments were conducted out by a high frequency fatigue test machine named GPS-100. The experimental results showed that the fatigue life of AFS decreased with the increasing loading level and the structure was sensitive to cyclic loading, especially when the loading level was under 20%. S-N curves of nine groups of AFS specimens were obtained and the fatigue life of AFS followed three-parameter lognormal distribution well. AFS under low cyclic loading showed pronounced cyclic hardening and the static strength after fatigue test increased. For the same loading level, effects of foam core density and face-sheet thickness on the fatigue life of AFS structure were trade-off and for the same loading value, the fatigue life of AFS increased with aluminum foam core density or face-sheet thickness monotonously. Core shear was the main failure mode in the present study.

• Journal of Radiation Protection and Research
• /
• v.21 no.2
• /
• pp.139-143
• /
• 1996

A multi-wire proportional counter with large sensitive area was designed and constructed considering diameter of anode wire. its material and space. A preamplifier connecting detector to main amplifier or counter was also designed and constructed for measurement output pulse from multi-wire proportional counter. The preamplifier was composed of charge-sensitive differential circuit. clipping circuit and amplification circuit. To test the performance of this equipment, terminal output pulse from the preamplifier was measured and compared with noise For these tests $^{239}Pu(360 Bq)\;and\; ^{90}Sr/^{90}Y(250 Bq)$ were used as radiation sources. The noise ingredient contributing to the maximum amplitude(180mV from $^{239}Pu$ and 200 mV from $^{90}Sr/^{90}Y$) was found to be very small(8 mV) Piled up pulse occurring at the output pulse of charge-sensitive differential circuit was measured as an independent pulse since this affected the amplification in the clipping circuit and amplification circuit. This information can be used to improve the loss of measurement due to piled up pulse.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.27 no.4
• /
• pp.961-970
• /
• 2017

The differential power analysis calculates the intermediate value related to sensitive information and substitute into the power model to obtain (hypothesized) power consumption. After analyzing the calculated power consumption and measuring power consumption, the secret information value can be obtained. Hamming weight and hamming distance models are most commonly used power consumption model, and the power consumption model is obtained through the modeling technique. If the power consumption model assumed by the actual equipment differs from the power consumption of the actual equipment, the side channel analysis performance is declined. In this paper, we propose a method that records measured power consumption and exploits as power consumption model. The proposed method uses the power consumption at the time when the information (plain text, cipher text, etc.) available in the encryption process. The proposed method does not need template in advance and uses the power consumption measured by the actual equipment, so it accurately reflects the power consumption model of the equipment.. Simulation and experiments show that by using our proposed method, side channel analysis is improved on the existing power modeling method.