S. Oukach^1,2,3, H. Hamdi², M. El Ganaoui⁴, B. Pateyron¹

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.2, pp. 173-196, 2012, DOI:10.3970/fdmp.2012.008.173

Abstract The splat formation is one of the basic processes in thermal spray coatings. The performance of these coatings is strongly related to the process of spreading and solidification of molten droplets. The aim of the present paper is to simulate the fluid flow, heat transfer and phase-change that occur when a micrometric molten droplet impacts onto a rigid substrate and to examine the effect of the substrate conditions, such as initial temperature and material on the solidification time and spreading process. The effect of thermal contact resistance is also investigated. The simulation model used is based on the Navier-Stokes equations… More >

S. Sabbaghi¹, M. Shariaty-Niassar², Sh. Ayatollahi¹, A. Jahanmiri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.2, pp. 113-124, 2008, DOI:10.3970/fdmp.2008.004.113

Abstract In this study, the Onset of Asphaltene Precipitation is predicted by a modified Virial equation of state. The bases of quantum mechanics and statistical thermodynamics are used to evaluate the potential energy and intermolecular forces related to asphaltene molecules. The Virial equation of state is modified using group-contribution-methods for asphaltenes, which are assumed to be polymeric-like compounds consisting of aggregates of monodisperse asphaltene monomers. It is shown how the modified Virial equation of state with the Peneloux correction leads to estimate the molar volume and solubility parameter. These parameters are also compared successfully with results provided by the Soave-Redlich-Kwong equation… More >

A.K. Plappally¹, M.A.R. Sharif¹, R.C. Bradt²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.2, pp. 115-128, 2007, DOI:10.3970/fdmp.2007.003.115

Abstract A novel physical chemical filtration process in a tundish for removal of inclusion particles from molten steel is proposed and analyzed. The considered inclusion particles are mainly composed of the minerals alumina (Al2O3 and spinel (MgAl2O4, which have an affinity to adhere (on contact) to an inclusion trap. An industrial tundish is considered and modified with a zigzag channel block insert installed across the molten steel flow so that when the molten steel flows through the zigzag channels, the inclusion particles are driven into contact with the channel surfaces by increased recirculation and turbulence. The inclusions will bond with the… More >

Sheng Bin^1,*, Gengxin Sun¹, Ning Cao², Jinming Qiu², Zhiyong Zheng³, Guohua Yang⁴, Hongyan Zhao⁵, Meng Jiang⁶, Lina Xu⁷

CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 659-674, 2019, DOI:10.32604/cmc.2019.05858

Abstract Recommendation system is one of the most common applications in the field of big data. The traditional collaborative filtering recommendation algorithm is directly based on user-item rating matrix. However, when there are huge amounts of user and commodities data, the efficiency of the algorithm will be significantly reduced. Aiming at the problem, a collaborative filtering recommendation algorithm based on multi-relational social networks is proposed. The algorithm divides the multi-relational social networks based on the multi-subnet complex network model into communities by using information dissemination method, which divides the users with similar degree into a community. Then the user-item rating matrix… More >

Chunfang Yang^1,*, Jie Wang¹, Chengliang Lin¹, Huiqin Chen², Wenjuan Wang¹

CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 633-644, 2019, DOI:10.32604/cmc.2019.06154

Abstract For the case of that only a single stego image of LSB (Least Significant Bit) matching steganography is available, the existing steganalysis algorithms cannot effectively locate the modified pixels. Therefore, an algorithm is proposed to locate the modified pixels of LSB matching based on spatial and wavelet filter fusion. Firstly, the validity of using the residuals obtained by spatial and wavelet filtering to locate the modified pixels of LSB matching is analyzed. It is pointed out that both of these two kinds of residuals can be used to identify the modified pixels of LSB matching with success rate higher than… More >

Wentao Ma¹, Jiaohua Qin^1,*, Xuyu Xiang¹, Yun Tan¹, Yuanjing Luo¹, Neal N. Xiong²

CMC-Computers, Materials & Continua, Vol.58, No.3, pp. 665-677, 2019, DOI:10.32604/cmc.2019.05683

Abstract As the first barrier to protect cyberspace, the CAPTCHA has made significant contributions to maintaining Internet security and preventing malicious attacks. By researching the CAPTCHA, we can find its vulnerability and improve the security of CAPTCHA. Recently, many studies have shown that improving the image preprocessing effect of the CAPTCHA, which can achieve a better recognition rate by the state-of-the-art machine learning algorithms. There are many kinds of noise and distortion in the CAPTCHA images of this experiment. We propose an adaptive median filtering algorithm based on divide and conquer in this paper. Firstly, the filtering window data quickly sorted… More >

Gongshen Liu¹, Kui Meng^1,*, Jiachen Ding¹, Jan P. Nees¹, Hongyi Guo¹, Xuewen Zhang¹

CMC-Computers, Materials & Continua, Vol.58, No.1, pp. 101-120, 2019, DOI:10.32604/cmc.2019.03898

Abstract Collaborative filtering is the most popular approach when building recommender systems, but the large scale and sparse data of the user-item matrix seriously affect the recommendation results. Recent research shows the user’s social relations information can improve the quality of recommendation. However, most of the current social recommendation algorithms only consider the user's direct social relations, while ignoring potential users’ interest preference and group clustering information. Moreover, project attribute is also important in item rating. We propose a recommendation algorithm which using matrix factorization technology to fuse user information and project information together. We first detect the community structure using… More >

Lihua Zhu¹, Yu Wang¹, Lei Wang², Zhiqiang Wu^1,*

CMC-Computers, Materials & Continua, Vol.59, No.3, pp. 1015-1026, 2019, DOI:10.32604/cmc.2019.05656

Abstract The performance of the transfer alignment has great impact on inertial navigation systems. As the transfer alignment is generally implemented using a filter to compensate the errors, its accuracy, rapidity and anti-disturbance capability are key properties to evaluate the filtering process. In terms of the superiority in dealing with the noise, H∞ filtering has been used to improve the anti-disturbance capability of the transfer alignment. However, there is still a need to incorporate system uncertainty due to various dynamic conditions. Based on the structural value theory, a robustness stability analysis method has been proposed for the transfer alignment to evaluate… More >

Taoyun Zhou^1,2, Baowang Lian¹, Siqing Yang^2,*, Yi Zhang¹, Yangyang Liu^1,3

CMC-Computers, Materials & Continua, Vol.56, No.2, pp. 225-245, 2018, DOI: 10.3970/cmc.2018.02671

Abstract For situations such as indoor and underground parking lots in which satellite signals are obstructed, GNSS cooperative positioning can be used to achieve high-precision positioning with the assistance of cooperative nodes. Here we study the cooperative positioning of two static nodes, node 1 is placed on the roof of the building and the satellite observation is ideal, node 2 is placed on the indoor windowsill where the occlusion situation is more serious, we mainly study how to locate node 2 with the assistance of node 1. Firstly, the two cooperative nodes are located with pseudo-range single point positioning, and the… More >

Zhenjun Tang^1,*, Man Ling¹, Heng Yao¹, Zhenxing Qian², Xianquan Zhang¹, Jilian Zhang³, Shijie Xu¹

CMC-Computers, Materials & Continua, Vol.55, No.2, pp. 331-344, 2018, DOI:10.3970/cmc.2018.02222

Abstract Image hashing is a useful multimedia technology for many applications, such as image authentication, image retrieval, image copy detection and image forensics. In this paper, we propose a robust image hashing based on random Gabor filtering and discrete wavelet transform (DWT). Specifically, robust and secure image features are first extracted from the normalized image by Gabor filtering and a chaotic map called Skew tent map, and then are compressed via a single-level 2-D DWT. Image hash is finally obtained by concatenating DWT coefficients in the LL sub-band. Many experiments with open image datasets are carried out and the results illustrate… More >