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Blind Watermarking Scheme based on U matrix Through QSVD Transformation
Feng Liu,Hao Feng,Chao Lu 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.4
In this paper, a novel blind color image watermarking technique using U matrix through QSVD transformation is proposed to protect the intellectual property rights of color images. The proposed method tries to insert the watermark through moderating the coefficient of the quaternion elements in U matrix. .In this method, the color image is considered as an array of pure quaternion numbers. Then the array of pure quaternion is divided into non-overlapping blocks and we perform QSVD to the block to get the U matrix. The watermarking is inserted into the coefficient of the quaternion elements in the first column of the U matrix. Besides, in the procedure of watermark insertion and extraction, ensuring higher fidelity and robustness and resilience to several possible image attacks have been considered. The experimental results showed that the proposed method performance created watermarked images with better PSNRs and more robustness versus several attacks such as Salt &Pepper noise, Brightness adjustment, Sharpen and Blurring and Clipping.
A Novel Blind Watermarking Scheme based on Quaternion and Joint SVD Blocks
Feng Liu,Hao Feng 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.4
In this paper, a novel blind color image watermarking technique using Quaternion and Joint QSVD Blocks is proposed to protect the intellectual property rights of color images. The proposed method tries to insert the watermark in the joint blocks .In this method, the color image is considered as an array of pure quaternion numbers. Then the array of pure quaternion is divided into non-overlapping blocks and performs QSVD to the blocks. The watermarking is inserted into the S blocks by changing the 2 of S of two adjacent blocks. Besides, in the procedure of watermark insertion and extraction, ensuring higher fidelity and robustness and resilience to several possible image attacks have been considered. The experimental results showed that the proposed method performance created watermarked images with better PSNRs and more robustness versus several attacks such as JPEG, Salt &Pepper noise, Brightness adjustment, Sharpen and Blurring.
Boundedness and continuity for variation operators on the Triebel--Lizorkin spaces
Feng Liu,Yongming Wen,Xiao Zhang 대한수학회 2022 대한수학회보 Vol.59 No.6
In this paper, we establish the boundedness and continuity for variation operators for $\theta$-type Calder\'{o}n--Zygmund singular integrals and their commutators on the Triebel--Lizorkin spaces. As applications, we obtain the corresponding results for the Hilbert transform, the Hermit Riesz transform, Riesz transforms and rough singular integrals as well as their commutators.
Recursive Design of Nonlinear Disturbance Attenuation Control for STATCOM
Feng Liu,Shengwei Mei,Qiang Lu,Masuo Goto 대한전기학회 2005 International Journal of Control, Automation, and Vol.3 No.2
In this paper, a nonlinear robust control approach is applied to design a controller for the Static Synchronous Compensator (STATCOM). A robust control dynamic model of STATCOM in a one-machine, infinite-bus system is established with consideration of the torque disturbance acting on the rotating shaft of the generator set and the disturbance to the output voltage of STATCOM. A novel recursive approach is utilized to construct the energy storage function of the system such that the solution to the disturbance attenuation control problem is acquired, which avoids the difficulty involved in solving the Hamilton-Jacobi-Issacs (HJI) inequality. Sequentially, the nonlinear disturbance attenuation control strategy of STATCOM is obtained. Simulation results demonstrate that STATCOM with the proposed controller can more effectively improve the voltage stability, damp the oscillation, and enhance the transient stability of power systems compared to the conventional PI+PSS controller.
Numerical Design Method for Water-Lubricated Hybrid Sliding Bearings
Feng, Liu,Bin, Lin,Xiaofeng, Zhang Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.1
This paper presents a new water-lubricated hybrid sliding bearing for a high speed and high accuracy main shaft system, along with the numerical method used for its design. The porous material for the restrictor and the restriction parameter were chosen based on the special requirements of the water-lubricated bearing. Subsequent numerical calculations give the load capacity, stiffness, and friction power of different forms of water-lubricated bearings. The pressure distribution of the water film in a 6-cavity bearing is shown, based on the results of the numerical calculations. A comparison of oil-lubricated and water-lubricated bearings shows that the latter benefits more from improved processing precision and efficiency. An analysis of the stiffness and friction power results shows that 6-cavity bearings are the preferred type, due their greater stiffness and lower friction power. The average elevated temperature was calculated and found to be satisfactory. The relevant parameters of the porous restrictor were determined by calculating the restriction rate. All these results indicate that this design for a water-lubricated bearing meets specifications for high speed and high accuracy.
( Feng Liu ),( Yueping Cao ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.8
Glyphosate inhibits the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the shikimate pathway. A mutant of EPSPS from Pantoea sp. was identified using sitedirected mutagenesis. The mutant showed significantly improved glyphosate resistance. The mutant had mutations in three amino acids: Gly97 to Ala, Thr 98 to Ile, and Pro 102 to Ser. These mutation sites in Escherichia coli have been studied as significant active sites of glyphosate resistance. However, in our research, they were found to jointly contribute to the improvement of glyphosate tolerance. In addition, the level of glyphosate tolerance in transgenic Arabidopsis confirmed the potentiality of the mutant in breeding glyphosateresistant plants.
AN IDENTITY ON THE 2m-TH POWER MEAN VALUE OF THE GENERALIZED GAUSS SUMS
Feng Liu,Quan-Hui Yang 대한수학회 2012 대한수학회보 Vol.49 No.6
In this paper, using analytic method and the properties of the Legendre's symbol, we prove an exact calculating formula on the $2m$-th power mean value of the generalized quadratic Gauss sums for $m{\geq}2$. This solves a conjecture of He and Zhang [On the 2k-th power mean value of the generalized quadratic Gauss sums, Bull. Korean Math. Soc. 48 (2011), no. 1, 9-15].