Yeungjin College

Buk Gu, South Korea

Yeungjin College

Buk Gu, South Korea
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Kim G.-S.,Yeungjin College | Lee S.-H.,Inha University
IEEE Transactions on Plasma Science | Year: 2011

The surface reconstruction of MgO by ion sputtering and redeposition brings about changes in discharge characteristics of AC-PDP. The more the number of discharges in cells is increased, the more the instability of discharge is increased. As discharges continuously occur, the microstructure of MgO is changed, and the time lag of the discharge is increased. In this paper, we present the mechanism of misdischarges, such as bright noise and black noise, by analyzing aging characteristics. Also, we found that misdischarges are closely connected with the exoelectron emission, which strongly influences the lag time of discharge, from a MgO surface. Moreover, we expressed the instability of reset discharge in terms of the lag time of the discharge and the probability of the strong dark discharge in the reset period. © 2011 IEEE.


Jung K.-H.,Yeungjin College | Yoo K.-Y.,Kyungpook National University
Multimedia Tools and Applications | Year: 2014

In this paper we propose a data hiding method that utilizes image interpolation and an edge detection algorithm. Image interpolation algorithm enlarges a cover image before hiding secret data in order to embed a large amount of secret data. Edge detection algorithm is applied to improve a quality of stego-image. Experimental results show that the proposed method can embed a large amount of secret data while keeping visual quality better than previous works. We demonstrate that the average capacity is 391,115bits, and the PSNR and quality index are 44.71dB, 0.9568 for gray images when threshold value is 4 and the embedding bits are given to 2 respectively. © 2012 Springer Science+Business Media New York.


Jung K.-H.,Yeungjin College | Yoo K.-Y.,Kyungpook National University
Multimedia Tools and Applications | Year: 2015

In this paper, a high-capacity data hiding method based on the index function is presented. The cover image is divided into non-overlapping sub-blocks, and the basis pixel is calculated by the index function. Difference values with other pixel-pairs are referenced to decide the number of embedding secret bits with the range table. The experimental results demonstrate that the proposed method could embed 2.45 bpp on average without distortion to the human visual system. We showed that the embedding capacity of the proposed method is 214,227 bits, 213,879 bits, 9,445 bits, 12,240 bits, and 109,253 bits larger than previous works on average for 12 test images. © 2014, Springer Science+Business Media New York.


Jung K.-H.,Yeungjin College | Yoo K.-Y.,Kyungpook National University
Multimedia Tools and Applications | Year: 2015

Steganography is the method of hiding secret data in other data, such as video or an image. A reversible data hiding method can extract the cover image from a stego-image without distortion after extracting the hidden data. In this paper a semi-reversible data hiding method that utilizes interpolation and the least significant substitution technique is proposed. First, interpolation methods are used to scale up and down the cover image before hiding secret data for a higher capacity and quality. Secondly, the LSB substitution method is used to embed secret data. Experimental results show that the proposed method can embed a large amount of secret data while keeping very high visual quality, where the PSNR is guaranteed to be 37.54 dB (k = 3) and 43.94 dB (k = 2). © 2014, Springer Science+Business Media New York.


Jung K.-H.,Yeungjin College
Imaging Science Journal | Year: 2010

In this paper, we propose a high capacity steganographic method using modulus function of pixel-value differencing (PVD) and least significant bit (LSB) replacement methods. Many steganographic methods based on LSB and PVD methods were presented to enlarge hiding capacity and provide an imperceptible image quality, but still have a room to improve the hiding capacity. The main idea of the proposed method is that secret data can be embedded on the smooth area by LSB substitution and on the edge area by PVD with less distortion to the human visual system and improvement of the embedding capacity. The experimental results show that the proposed method sustains a higher capacity and still a good quality compared with LSB and PVD methods. © 2010 RPS.


Jeong B.-W.,Yeungjin College | Jeong B.-W.,University of Florida | Sinnott S.B.,University of Florida
Carbon | Year: 2010

Buckling responses of multi-walled carbon nanotubes incorporated as torsion springs in electromechanical devices are predicted via classical molecular dynamics simulations. The observations reveal that the outermost walls of the nanotubes act as torsion springs and possess not only greatly enhanced first buckling strengths, but also stiffened post-buckling regimes characterized by a slight growth of helicoidal ridges and furrows. As a result, a second buckling point appears at a larger torque than the first one, with a positive torsional stiffness of about 55% relative to the value in the pre-buckling regime. Interestingly, these unique buckling responses are mainly caused by the presence of the third outermost wall acting as a hard core. © 2009 Elsevier Ltd. All rights reserved.


Lee J.-Y.,Kangwon National University | Han J.,Yeungjin College
Natural Resources Research | Year: 2013

The objective of this study was to evaluate groundwater conditions in the four greatest megacities (Seoul, Busan, Daegu, and Incheon) of Korea using 5-year (2006-2010) monitoring data obtained from the Korean National Groundwater Monitoring Stations. With decreasing of groundwater draft, groundwater levels for the 5-year period were not substantially decreasing but they responded differently to outer stress like rainfall according to degree of urbanization or pavement of surrounding areas. However, groundwater and air temperatures were gradually increasing due to the widespread climate change. Coastal groundwaters (Seoul, Busan, and Incheon) have suffered from seawater intrusion, which can be aggravated by sea level rise in the future. Some monitoring stations of the megacities observed a drastic decrease of groundwater level for a specific period and the marked increasing of electrical conductivity; thus, detailed investigations revealing the causes and appropriate mitigation measures are required. Urban groundwater did not uniformly respond to outer anthropogenic and natural stresses because a variety of human interventions are differently involved. © 2013 International Association for Mathematical Geology.


Jung K.-H.,Yeungjin College | Yoo K.-Y.,Kyungpook National University
Information Sciences | Year: 2014

This paper proposes a new data hiding method for binary images that relies on block masking to distribute keys to two parts and then authenticates the right authorized part. The proposed method divides a cover image into small sub-blocks and designs key pairs that determine both where the bit is to be embedded and whether it is possible to embed it there. Furthermore, the key pairs are required to extract the secret data from the stego-image. Experimental results demonstrate a higher capacity and less distortion compared with previous methods since almost all data are hidden in the edge areas. © 2014 Elsevier Inc. All rights reserved.


Kim G.-S.,Yeungjin College | Lee S.-H.,Inha University
IEEE Transactions on Plasma Science | Year: 2010

As the temperature of the panel increases in AC-PDPs, the minimum driving voltage increases. Thus, the driving voltage margin is not sufficient at high temperature. In this paper, we have investigated the mechanism of a misdischarge which is generated due to the decrement of the driving voltage margin at high temperature. The main factor of the high-temperature misdischarge is the increased electron emission ability from the MgO surface. We have confirmed that the wall charge loss in the address period is the largest among the driving periods. We have verified that the wall charge loss at high temperature depends on not only the voltage difference but also the time when the voltage difference is applied. Therefore, the wall charge loss is influenced by the number of sustain discharges in the previous subfield and address load. Finally, we have improved the driving voltage margin at high temperature using a narrow scan time and a high scan voltage in a 50-in panel with HD resolution. © 2006 IEEE.


Jung K.-H.,Yeungjin College
Imaging Science Journal | Year: 2012

Data hiding in binary images is difficult since only 1 bit is used to represent 1 pixel and distortion is conspicuous. In this paper, we propose a data hiding method in binary images by checking the bit position and parity bit to hide a secret bit in binary images. The cover image is divided intoM ± N sub-blocks and the parity bit of sub-block pixels are referenced to embed a secret bit for the suitable pixel. By finding the suitable pixel position to insert a secret bit for each sub-block, the image quality of the stego-image can be improved, while maintaining a low computational complexity. The experimental results show that the proposed method has a higher capacity and better visual quality as increasing a size of sub-block. © RPS 2012.

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