Xuyu Xiang¹, Jiaohua Qin^{1, *}, Junshan Tan¹, Neal N. Xiong¹

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 963-976, 2020, DOI:10.32604/cmc.2020.06394

Abstract In this paper, a new adaptive calibration algorithm for image steganalysis is proposed. Steganography disturbs the dependence between neighboring pixels and decreases the neighborhood node degree. Firstly, we analyzed the effect of steganography on the neighborhood node degree of cover images. Then, the calibratable pixels are marked by the analysis of neighborhood node degree. Finally, the strong correlation calibration image is constructed by revising the calibratable pixels. Experimental results reveal that compared with secondary steganography the image calibration method significantly increased the detection accuracy for LSB matching steganography on low embedding ratio. The proposed method More >

Wujie Hu¹, Gonglin Yuan^{1, *}, Hongtruong Pham²

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 787-800, 2020, DOI:10.32604/cmc.2020.02993

Abstract It is well known that Newton and quasi-Newton algorithms are effective to small and medium scale smooth problems because they take full use of corresponding gradient function’s information but fail to solve nonsmooth problems. The perfect algorithm stems from concept of ‘bundle’ successfully addresses both smooth and nonsmooth complex problems, but it is regrettable that it is merely effective to small and medium optimization models since it needs to store and update relevant information of parameter’s bundle. The conjugate gradient algorithm is effective both large-scale smooth and nonsmooth optimization model since its simplicity that utilizes More >

Huan Zhang¹, Kangfeng Zheng^{1, *}, Xiujuan Wang², Shoushan Luo¹, Bin Wu¹

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 763-786, 2020, DOI:10.32604/cmc.2020.06553

Abstract As a core component of the network, web applications have become one of the preferred targets for attackers because the static configuration of web applications simplifies the exploitation of vulnerabilities by attackers. Although the moving target defense (MTD) has been proposed to increase the attack difficulty for the attackers, there is no solo approach can cope with different attacks; in addition, it is impossible to implement all these approaches simultaneously due to the resource limitation. Thus, the selection of an optimal defense strategy based on MTD has become the focus of research. In general, the… More >

Yinghang Jiang¹, Qi Liu^2,3,*, Williams Dannah¹, Dandan Jin², Xiaodong Liu³, Mingxu Sun^4,*

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 713-729, 2020, DOI:10.32604/cmc.2020.04604

Abstract Hadoop is a well-known parallel computing system for distributed computing and large-scale data processes. “Straggling” tasks, however, have a serious impact on task allocation and scheduling in a Hadoop system. Speculative Execution (SE) is an efficient method of processing “Straggling” Tasks by monitoring real-time running status of tasks and then selectively backing up “Stragglers” in another node to increase the chance to complete the entire mission early. Present speculative execution strategies meet challenges on misjudgement of “Straggling” tasks and improper selection of backup nodes, which leads to inefficient implementation of speculative executive processes. This paper… More >

Fatima Bayones¹, Abdelmooty Abd-Alla^{2, *}, Raghad Alfatta³, Hoda Al-Nefaie³

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 551-567, 2020, DOI:10.32604/cmc.2020.08420

Abstract The propagation of thermoelastic waves in a homogeneous, isotropic elastic semi-infinite space is subjected to rotation and initial stress, which is at temperature T₀ - initially, and whose boundary surface is subjected to heat source and load moving with finite velocity. Temperature and stress distribution occurring due to heating or cooling and have been determined using certain boundary conditions. Numerical results have been given and illustrated graphically in each case considered. Comparison is made with the results predicted by the theory of thermoelasticity in the absence of rotation and initial stress. The results indicate that the More >

Mohamed Abd El-Aziz^{1, 2}, A. M. Aly^{1, 3, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 525-549, 2020, DOI:10.32604/cmc.2020.08576

Abstract This study focusses on the numerical investigations of boundary layer flow for magnetohydrodynamic (MHD) and a power-law nanofluid containing gyrotactic microorganisms on an exponentially stretching surface with zero nanoparticle mass flux and convective heating. The nonlinear system of the governing equations is transformed and solved by Runge-Kutta-Fehlberg method. The impacts of the transverse magnetic field, bioconvection parameters, Lewis number, nanofluid parameters, Prandtl number and power-law index on the velocity, temperature, nanoparticle volume fraction, density of motile microorganism profiles is explored. In addition, the impacts of these parameters on local skin-friction coefficient, local Nusselt, local Sherwood… More >

Abdelghani Hassainia¹, Hamid Satha^1,*, Boufi Sami²

Journal of Renewable Materials, Vol.8, No.1, pp. 101-111, 2020, DOI:10.32604/jrm.2020.07725 - 01 January 2020

Abstract Two methods were used to produce chitosan by deacetylation of chitin which was extracted from Agaricus bisporus stipes. The first one gives chitosan 1 with low yield of 2.5%, degree of acetylation (DA) of 4%, molecular weight (MW) of 2.973 × 10⁵ (g/mol). The second route produces chitosan 2 with higher yield of 41%, degree of acetylation (DA) of 17.23%, molecular weight (MW) of 2.939 × 10⁵ (g/mol). Both chitosans were characterized by XRD, FTIR, ¹ H-NMR spectroscopy nuclear magnetic resonance of proton. The molecular weight (M_W) was determined by size exclusion chromatography (SEC). Thermal analysis shows that More >

Ali Abdelmoteleb¹, Benjamin Valdez-Salas², Ernesto Beltran-Partida², Daniel Gonzalez-Mendoza^3,*

Journal of Renewable Materials, Vol.8, No.1, pp. 69-78, 2020, DOI:10.32604/jrm.2020.08334 - 01 January 2020

Abstract The aim of this study was to evaluate the antibacterial and antifungal activities of eco-friendly synthesized silver nanoparticles. The silver nanoparticles were synthesized by biological method using aqueous extract of Abronia villosa. Synthesis of silver nanoparticles was confirmed by color change and characterized using UV-visible spectroscopy, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and zeta potential analysis. The SEM analysis revealed the presence of spherical silver nanoparticles of the size range 21 to 33 nm. Synthesized silver nanoparticles were used to evaluate their antibacterial effects at different concentrations (25, 50, More >

Haiyang Ding^1,2,3,4,5, Xiaohua Yang^1,2,3,4,5, Lina Xu^1,2,3,4,5, Shouhai Li^1,2,3,4,5, Jianling Xia^1,2,3,4,5, Mei Li^1,2,3,4,5,*

Journal of Renewable Materials, Vol.8, No.1, pp. 1-11, 2020, DOI:10.32604/jrm.2020.08165 - 01 January 2020

Abstract Thermosetting polyurethanes are widely used in various fields owing to their excellent elasticity, strength and solvent resistance. Three environmental friendly propyl gallate-based self-healing polyurethanes were prepared from polyurethane prepolymers with varying isocyanate content. The thermal stabilities of the polyurethanes were tested using thermogravimetric analysis. Their self-healing and mechanical properties were analyzed using a universal testing machine and dynamic thermomechanical analysis. The polyurethanes were found with high self-healing ability and excellent mechanical properties due to the absence of phenolic carbamate. These qualities improved with increased isocyanate content and the prolonged selfhealing time. We found, therefore, that More >

Yanlin Zhao^{1, 2, *}, Jiansha Lu¹, Qing Yan¹, Lili La¹, Lili Xu¹

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 355-364, 2020, DOI:10.32604/cmc.2020.06396

Abstract With the rapid development of the individualized demand market, the demand for manufacturing flexibility has increased over time. As a result, a cell manufacturing system suitable for many varieties and small batches has been produced. With the goal of minimizing the area and logistics handling volume, and considering the arrangement order of facilities and channel constraints, a mathematical model was established, and the problem was solved by improved NSGA-II. After non-dominated sorting, traditional NSGA-II will cross-operate the individuals with the best sorting to generate new individuals. Such a selection strategy is extremely easy to fall… More >