Fengrui Liu^{1, 2, 3}, Wanting Yao^{1, 2}, Xinhong Shi^{4, *}, Libin Zhao^{1, 2}, Jianyu Zhang^{5, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 977-999, 2020, DOI:10.32604/cmc.2020.07184

Abstract To minimize the mass and increase the bearing failure load of composite doublelap bolted joints, a three-step optimization strategy including feasible region reduction, optimization model decoupling and optimization was presented. In feasible region reduction, the dimensions of the feasible design region were reduced by selecting dominant design variables from numerous multilevel parameters by sensitivity analyses, and the feasible regions of variables were reduced by influence mechanism analyses. In model decoupling, the optimization model with a large number of variables was divided into various sub-models with fewer variables by variance analysis. In the third step, the optimization sub-models were solved one… More >

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 also has a better performance… More >

Weihua Fang¹, Zhilin An², Tiantang Yu^{2, *}, Tinh Quoc Bui^{3, 4, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 929-962, 2020, DOI:10.32604/cmc.2020.05022

Abstract Numerical analysis of unsteady heat transfer problems with complex geometries by the isogeometric boundary element method (IGABEM) is presented. The IGABEM possesses many desirable merits and features, for instance, (a) exactly represented arbitrarily complex geometries, and higher-order continuity due to nonuniform rational B-splines (NURBS) shape functions; (b) using NURBS for both field approximation and geometric description; (c) directly utilizing geometry data from computer-aided design (CAD); and (d) only boundary discretization. The formulation of IGABEM for unsteady heat transfer is derived. The domain discretization in terms of IGABEM for unsteady heat transfer is required as that in traditional BEM. The internal… More >

Haiwen Chen¹, Guang Yu¹, Fang Liu², Zhiping Cai^{1, *}, Anfeng Liu³, Shuhui Chen¹, Hongbin Huang¹, Chak Fong Cheang⁴

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 917-927, 2020, DOI:10.32604/cmc.2020.05981

Abstract For many Internet companies, a huge amount of KPIs (e.g., server CPU usage, network usage, business monitoring data) will be generated every day. How to closely monitor various KPIs, and then quickly and accurately detect anomalies in such huge data for troubleshooting and recovering business is a great challenge, especially for unlabeled data. The generated KPIs can be detected by supervised learning with labeled data, but the current problem is that most KPIs are unlabeled. That is a time-consuming and laborious work to label anomaly for company engineers. Build an unsupervised model to detect unlabeled data is an urgent need… More >

Yong Yan¹, Yao Dai^{2, *}, Zhiqiang Zhou³, Wei Jiang⁴, Shaoyong Guo²

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 905-915, 2020, DOI:10.32604/cmc.2020.07425

Abstract Internet of Things (IoT) technology is rapidly evolving, but there is no trusted platform to protect user privacy, protect information between different IoT domains, and promote edge processing. Therefore, we integrate the blockchain technology into constructing trusted IoT platforms. However, the application of blockchain in IoT is hampered by the challenges posed by heavy computing processes. To solve the problem, we put forward a blockchain framework based on mobile edge computing, in which the blockchain mining tasks can be offloaded to nearby nodes or the edge computing service providers and the encrypted hashes of blocks can be cached in the… More >

Tingting Zhang^{1, 2, 3, *}, Yushi Lan², Minggang Yu¹, Changyou Zheng¹, Kun Liu¹

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 893-904, 2020, DOI:10.32604/cmc.2020.06216

Abstract Web Services Choreography Description Language lacks a formal system to accurately express the semantics of service behaviors and verify the correctness of a service choreography model. This paper presents a new approach of choreography model verification based on Description Logic. A meta model of service choreography is built to provide a conceptual framework to capture the formal syntax and semantics of service choreography. Based on the framework, a set of rules and constraints are defined in Description Logic for choreography model verification. To automate model verification, the UML-based service choreography model will be transformed, by the given algorithms, into the… More >

Yali Wang¹, Youqian Feng¹, Zhonghai Yin¹, Cheng Zhou^{1, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 877-891, 2020, DOI:10.32604/cmc.2020.06423

Abstract This paper researches some problems in complex formation for multi-agents, in which two matrices are proposed to record the formation. The pattern matrix is used to describe the pattern of the formation; meanwhile, the location matrix is used to record the location of each agent. Thus, all desired positions of each agent will be obtained by geometrical relationship on the basis of two matrices above. In addition a self-adaptation flocking algorithm is proposed to control all agents to form a desired formation and avoid obstacles. The main idea is as follows: agents will form a desired formation through the method… More >

Zengshan Tian¹, Weiqin Yang¹, Yue Jin¹, Liangbo Xie^{1, *}, Zhengwen Huang²

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 861-876, 2020, DOI:10.32604/cmc.2020.07297

Abstract With the popularity of indoor wireless network, device-free indoor localization has attracted more and more attention. Unlike device-based localization where the target is required to carry an active transmitter, their frequent signal scanning consumes a large amount of energy, which is inconvenient for devices with limited energy. In this work, we propose the MFPL, device-free localization (DFL) system based on WiFi distance measurement. First, we combine multi-subcarrier characteristic of Channel State Information (CSI) with classical Fresnel reflection model to get the linear relationship between the change of the length of reflection path and the subcarrier phase difference. Then we calculate… More >

Yuan Chen¹, Liangtao Duan¹, Weize Sun^{2, *}, Jingxin Xu³

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 849-859, 2020, DOI:10.32604/cmc.2020.07115

Abstract In this paper, we address the frequency estimator for 2-dimensional (2-D) complex sinusoids in the presence of white Gaussian noise. With the use of the sinc function model of the discrete Fourier transform (DFT) coefficients on the input data, a fast and accurate frequency estimator is devised, where only the DFT coefficient with the highest magnitude and its four neighbors are required. Variance analysis is also included to investigate the accuracy of the proposed algorithm. Simulation results are conducted to demonstrate the superiority of the developed scheme, in terms of the estimation performance and computational complexity. More >

Bo Gao^{1, *}, Xuan Liu¹, Xiaobo Wu^{1, *}, Shudong Li^{2, *}, Zhongzhou Lan¹, Hui Lu^{2, *}, Boyan Liu¹

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 833-847, 2020, DOI:10.32604/cmc.2020.06702

Abstract The stability of Non-Linear Feedback Shift Registers (NFSRs) plays an important role in the cryptographic security. Due to the complexity of nonlinear systems and the lack of efficient algebraic tools, the theorems related to the stability of NFSRs are still not well-developed. In this paper, we view the NFSR with periodic inputs as a Boolean control network. Based on the mathematical tool of semi-tensor product (STP), the Boolean network can be mapped into an algebraic form. Through these basic theories, we analyze the state space of non-autonomous NFSRs, and discuss the stability of an NFSR with periodic inputs of limited… More >