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Yanggu, South Korea

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

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.


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
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.


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.

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