• Journal of Electrical Engineering and Technology
• /
• v.10 no.5
• /
• pp.2197-2204
• /
• 2015

In recent years, medical image diagnosis has growing significant momentous in the medicinal field. Brain and lung image of patient are distorted with salt and pepper noise is caused by moving the head and chest during scanning process of patients. Reconstruction of these images is a most significant field of diagnostic evaluation and is produced clearly through techniques such as linear or non-linear filtering. However, restored images are produced with smaller amount of noise reduction in the presence of huge magnitude of salt and pepper noises. To eliminate the high density of salt and pepper noises from the reproduction of images, a new efficient fuzzy based median filtering algorithm with a moderate elapsed time is proposed in this paper. Reproduction image results show enhanced performance for the proposed algorithm over other available noise reduction filtering techniques in terms of peak signal -to -noise ratio (PSNR), mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), image enhancement factor (IMF) and structural similarity (SSIM) value when tested on different medical images like magnetic resonance imaging (MRI) and computer tomography (CT) scan brain image and CT scan lung image. The introduced algorithm is switching filter that recognize the noise pixels and then corrects them by using median filter with fuzzy two-sided π- membership function for extracting the local information.

• Bulletin of the Korean Mathematical Society
• /
• v.61 no.1
• /
• pp.93-115
• /
• 2024

In this paper, the Gauge-Uzawa methods for the Darcy-Brinkman equations driven by temperature and salt concentration (DBTC) are proposed. The first order backward difference formula is adopted to approximate the time derivative term, and the linear term is treated implicitly, the nonlinear terms are treated semi-implicit. In each time step, the coupling elliptic problems of velocity, temperature and salt concentration are solved, and then the pressure is solved. The unconditional stability and error estimations of the first order semi-discrete scheme are derived, at the same time, the unconditional stability of the first order fully discrete scheme is obtained. Some numerical experiments verify the theoretical prediction and show the effectiveness of the proposed methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.565-569
• /
• 1999

In these days, the silicone insulators have been increasingly studied and applied for outdoor insulators because it has superior characteristics than porcelain and glass insulators, which have been used for outdoor insulators. First of all, The excellent performance of the silicone rubber in polluted and wet conditions is attributed to the ability of the material to maintain the hydrophobicity of the surface in the presence of severe contamination and wet conditions. This is because of the presence of low molecular weight mobile fluid in the silicone rubber which diffuses to the surface and to above the contamination layer. But, the leakage current and some surface discharge occurs on surface of the composite polymeric insulation materials when the insulator is used for a long time with severe contaminative condition and it can lead the contamination flashover. So the leakage current and the discharge current are important to estimate the condition of the silicone rubber surface. In this paper, the average leakage current, the relation of surface discharge current and phase angle were study to investigate electrical conduction of silicone rubber surface with the salt fog condition.

• Nuclear Engineering and Technology
• /
• v.49 no.8
• /
• pp.1617-1628
• /
• 2017

In the passive residual heat removal system of a molten salt reactor, one of the residual heat removal methods is to use the thimble-type heat transfer elements of the drain salt tank to remove the residual heat of fuel salts. An experimental loop is designed and built with a single heat transfer element to analyze the heat transfer and flow characteristics. In this research, the influence of the size of a three-layer thimble-type heat transfer element on the heat transfer rate is analyzed. Two methods are used to obtain the heat transfer rate, and a difference of results between methods is approximately 5%. The gas gap width between the thimble and the bayonet has a large effect on the heat transfer rate. As the gas gap width increases from 1.0 mm to 11.0 mm, the heat transfer rate decreases from 5.2 kW to 1.6 kW. In addition, a natural circulation startup process is described in this paper. Finally, flashing natural circulation instability has been observed in this thimble-type heat transfer element.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.916-918
• /
• 2015

Image processing is being spotlighted as an important sector with increasingly diverse applications as the society advances into a sophisticated digital information age. Especially, the image restoration as the core technology of image processing, many studies are being progressed. In this paper, in order to restore the damaged image in the Salt and Pepper noisy environment, a modified adaptive switching median filter where the size of local mask can be varied according to the noise density was proposed. And using the PSNR as the standard for objective decision making of the improvement effect, it was compared with the existing methods.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.5
• /
• pp.331-337
• /
• 2017

Thermal batteries, reserve power source, is activated by melting of molten salt at the temperature range of $350{\sim}550^{\circ}C$. To immobile the molten state electrolyte when the thermal battery is activated, the binder must be added in electrolyte. Usually, molten salts include 30~40 wt% of MgO binder to ensure electrical insulation as well as safety. However, the conventional MgO binder tends to increase ionic conductive resistance and thus the inclusion of the binder increases the total impedance of the battery. This paper mainly focused on the study of yttria stabilized zirconia (YSZ) as an alternative binder for molten salt. The chemical stability between the molten salt and YSZ is measured by XRD and DSC. And the sufficient path for ionic conduction on molten salt could be confirmed by the enhanced wetting behavior and the enlarged pore size of YSZ. The electrochemical properties were analyzed using single cell tests so that it showed the outstanding performance than that using MgO binder.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.694-696
• /
• 2017

Image processing is being hailed as an important field with various applications as the digital information era advances. In particular, studies on methods to remove noise from images are being actively undertaken. This paper suggests an image restoration filter that processes through a weighted filter in accordance with the direction of partial masks to preserve edge while replacing the noise in the images with neighboring pixels. The PSNR(peak signal to noise ratio) was used as a tool to objectively judge the improvement effects compared to existing methods.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1832-1834
• /
• 2004

The degree of contamination on outdoor insulator is one of the most importance factors to determine the pollution level of outdoor insulations, and the sea salt is known as the most dangerous pollutant. As shown through the preceding study, the generation of salt pollutant and the pollution degree of outdoor insulator have a close relation with meteorological conditions, such as wind velocity, rainfall, and so on. So, in this paper, we have made database using the past meteorological data and ESDD(equivalent salt deposit density) and then we predicted the pollution degree in the future after analyzing currently meteorological data of database.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2001.11a
• /
• pp.199-202
• /
• 2001

This paper presents the correlation on the contamination degree and weather conditions using the multiple regression of the statistic method. The cotamination is a significant factor in the insulation system. The major factor is natural contamination, and the most is the salt. The salt contamination is occured by the weather conditions. The weather contaminations are wind, precipitation, temperature, relative humidity, etc. The effects of those are different, and the correlation is showed numerically by using the multiple regression method of the statistic method. With this, the estimation of the equivalent salt deposit density(ESDD) becomes possible by the changes of the weather conditions.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.1
• /
• pp.28-34
• /
• 2007

Recently, with the rapid growth of industry, environmental condition became worse. In addition to outdoor insulators in seashore are polluted due to salty wind. Also this pollution causes the flashover and failure of electric equipments. Especially the salt contaminant is one of the most representative pollutants, and known as the main source of the accident by contamination. As well known, the pollution has a close relation with meteorological factors such as wind velocity, wind direction, temperature, relative humidity, precipitation and so on. In this paper we have statistically analyzed the correlation between the pollution and the meteorological factors. The multiple regression analysis was used for the statistical analysis; daily measured equivalent salt deposit density(dependent variable) and the weather condition data(independent variable) were used. Also we have developed an expert program to predict the pollution deposit. A new prediction system using this program called SPPP(salt pollution prediction program) has been used to model accurately the relationship between ESDD with the meteorological factors.