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  • Open Access


    DSA-Based Quantitative Assessment of Cerebral Hypoperfusion in Patients with Asymmetric Carotid Stenosis

    Xu Zhang1,‡, Jie Gao2,‡, Xinke Yao1, Zhengze Dai3,4, Gelin Xu2,*, Yan Cai1,*, Zhiyong Li1,5,*

    Molecular & Cellular Biomechanics, Vol.16, No.1, pp. 27-39, 2019, DOI:10.32604/mcb.2019.06140

    Abstract Digital subtraction angiography (DSA) is often used to evaluate the morphological and pathological changes of cerebral arteries in clinical practice. This study aims to explore the possibility of assessing cerebral hypoperfusion with DSA in patients with carotid stenosis. Thirty patients with a mild to severe stenosis on one side, and a mild stenosis on the other side of the carotid artery were recruited. Frontal, parietal, temporal and occipital lobes were chosen as regions of interest for measuring the quantitative perfusion parameters from their time-density curves (TDCs) of DSA images. The perfusion parameters were compared between the two hemispheres by using… More >

  • Open Access


    An Asymmetric Controlled Bidirectional Quantum State Transmission Protocol

    Yiru Sun1,2, Yuling Chen1,*, Haseeb Ahmad3, Zhanhong Wei4

    CMC-Computers, Materials & Continua, Vol.59, No.1, pp. 215-227, 2019, DOI:10.32604/cmc.2019.05253

    Abstract In this paper, we propose an asymmetric controlled bidirectional transmission protocol. In the protocol, by using the thirteen-qubit entangled state as the quantum channel, Alice can realize the transmission of a two-qubit equatorial state for Bob and Bob can transmit a four-qubit equatorial state for Alice under the control of Charlie. Firstly, we give the construction of the quantum channel, which can be done by performing several H and CNOT operations. Secondly, through implementing the appropriate measurements and the corresponding recovery operations, the desired states can be transmitted simultaneously, securely and deterministically. Finally, we analyze the performance of the protocol,… More >

  • Open Access


    Efficient Secure Data Provenance Scheme in Multimedia Outsourcing and Sharing

    Zhen Yang1,2, Yongfeng Huang1,2,*, Xing Li1,2, Wenyu Wang3

    CMC-Computers, Materials & Continua, Vol.56, No.1, pp. 1-17, 2018, DOI: 10.3970/cmc.2018.03697

    Abstract To cope with privacy leakage caused by multimedia outsourcing and sharing, data provenance is used to analyze leaked multimedia and provide reactive accountability. Existing schemes of multimedia provenance are based on watermarking protocols. In an outsourcing scenario, existing schemes face two severe challenges: 1) when data leakage occurs, there exists a probability that data provenance results can be repudiated, in which case data provenance tracking fails; and 2) when outsourced data are shared, data encryption transfer causes key management burden outside the schemes, and privacy leakage threatens users. In this paper, we propose a novel data provenance scheme with an… More >

  • Open Access


    Modeling and Analysis of Novel Multilevel Inverter Topology with Minimum Number of Switching Components

    V. Thiyagarajan1, P. Somasundaram2

    CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 461-473, 2017, DOI:10.3970/cmes.2017.113.461

    Abstract This paper proposes a novel single phase symmetrical and asymmetrical type extendable multilevel inverter topology with minimum number of switches. The basic circuit of the proposed inverter topology consist of four dc voltage sources and 10 main switches which synthesize 9-level output voltage during symmetrical operation and 17-level output voltage during asymmetrical operation. The comparison between the proposed topology with conventional and other existing inverter topologies is presented in this paper. The advantages of the proposed inverter topology includes minimum switches, less harmonic distortion and minimum switching losses. The performance of the proposed multilevel inverter topology has been analyzed in… More >

  • Open Access


    Asymmetric Shell Elements Based on a Corrected Updated-Lagrangian Approach

    P. Areias1,2,3, T. Rabczuk4, D. Dias-da-Costa5,6

    CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.6, pp. 475-506, 2012, DOI:10.3970/cmes.2012.088.475

    Abstract Surprisingly good displacement results are obtained by using the Petrov-Galerkin method with assumed and enhanced metric components in the test functions and enhanced metric components in the trial functions. Cartesian trial functions are required to ensure completeness and assumed/enhanced metric components are introduced to ensure high coarse-mesh accuracy. In the trial functions, the original incompatible-mode in-plane Q6 element by Wilson et al. can be used without violating the patch test. As a beneficial side-effect, Newton-Raphson convergence behavior for non-linear problems is improved. Transverse-shear and in-plane patch tests are satisfied while distorted-mesh performance is better than with symmetric formulations due to… More >

  • Open Access


    Computations of a Compressible Turbulent Flow in a Rocket Motor-Chamber Configuration with Symmetric and Asymmetric Injection

    W.A. El-Askary1,2, A. Balabel2, S.M. El-Behery2, A. Hegab3

    CMES-Computer Modeling in Engineering & Sciences, Vol.82, No.1, pp. 29-54, 2011, DOI:10.32604/cmes.2011.082.029

    Abstract In the present paper, the characteristics of compressible turbulent flow in a porous channels subjected to either symmetric or asymmetric mass injection are numerically predicted. A numerical computer-program including different turbulence models has been developed by the present authors to investigate the considered flow. The numerical method is based on the control volume approach to solve the governing Reynolds-Averaged Navier-Stokes (RANS) equations. Turbulence modeling plays a significant role here, in light of the complex flow generated, so several popular engineering turbulence models with good track records are evaluated, including five different turbulence models. Numerical results with available experimental data showed… More >

  • Open Access


    Stable PDE Solution Methods for Large Multiquadric Shape Parameters

    Arezoo Emdadi1, Edward J. Kansa2, Nicolas Ali Libre1,3, Mohammad Rahimian1, Mohammad Shekarchi1

    CMES-Computer Modeling in Engineering & Sciences, Vol.25, No.1, pp. 23-42, 2008, DOI:10.3970/cmes.2008.025.023

    Abstract We present a new method based upon the paper of Volokh and Vilney (2000) that produces highly accurate and stable solutions to very ill-conditioned multiquadric (MQ) radial basis function (RBF) asymmetric collocation methods for partial differential equations (PDEs). We demonstrate that the modified Volokh-Vilney algorithm that we name the improved truncated singular value decomposition (IT-SVD) produces highly accurate and stable numerical solutions for large values of a constant MQ shape parameter, c, that exceeds the critical value of c based upon Gaussian elimination. More >

  • Open Access


    Identification of dynamical systems with fractional derivative damping models using inverse sensitivity analysis

    R Sivaprasad1,2, S Venkatesha1, C S Manohar1,3

    CMC-Computers, Materials & Continua, Vol.9, No.3, pp. 179-208, 2009, DOI:10.3970/cmc.2009.009.179

    Abstract The problem of identifying parameters of time invariant linear dynamical systems with fractional derivative damping models, based on a spatially incomplete set of measured frequency response functions and experimentally determined eigensolutions, is considered. Methods based on inverse sensitivity analysis of damped eigensolutions and frequency response functions are developed. It is shown that the eigensensitivity method requires the development of derivatives of solutions of an asymmetric generalized eigenvalue problem. Both the first and second order inverse sensitivity analyses are considered. The study demonstrates the successful performance of the identification algorithms developed based on synthetic data on one, two and a 33… More >

  • Open Access


    A New Locking Free Higher Order Finite Element Formulation for Composite Beams.

    M.V.V.S. Murthy1, S. Gopalakrishnan2,3, P.S. Nair4

    CMC-Computers, Materials & Continua, Vol.5, No.1, pp. 43-62, 2007, DOI:10.3970/cmc.2007.005.043

    Abstract A refined 2-node, 7 DOF/node beam element formulation is presented in this paper. This formulation is based on higher order shear deformation theory with lateral contraction for axial-flexural-shear coupled deformation in asymmetrically stacked laminated composite beams. In addition to axial, transverse and rotational degrees of freedom, the formulation also incorporates the lateral contraction and its higher order counterparts as degrees of freedom. The element shape functions are derived by solving the static part of the governing equations. The element considers general ply stacking and the numerical results shows that the element exhibits super convergent property. The efficiency of the element… More >

  • Open Access


    Controlled Cyclic Remote State Preparation of Arbitrary Qubit States

    Mingming Wang1,2,*, Chen Yang1, Reza Mousoli3

    CMC-Computers, Materials & Continua, Vol.55, No.2, pp. 321-329, 2018, DOI:10.3970/cmc.2018.02064

    Abstract Quantum secure communications could securely transmit quantum information by using quantum resource. Recently, novel applications such as bidirectional and asymmetric quantum protocols have been developed. In this paper, we propose a new method for generating entanglement which is highly useful for multiparty quantum communications such as teleportation and Remote State Preparation (RSP). As one of its applications, we propose a new type of quantum secure communications, i.e. cyclic RSP protocols. Starting from a four-party controlled cyclic RSP protocol of one-qubit states, we show that this cyclic protocol can be generalized to a multiparty controlled cyclic RSP protocol for preparation of… More >

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