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  • Open Access

    ARTICLE

    CHAOTIC NATURAL CONVECTION IN AN ANNULAR CAVITY WITH NON-ISOTHERMAL WALLS

    H.E. Dillon, A.F. Emery, A.M. Mescher, O. Sprenger, S.R. Edwards

    Frontiers in Heat and Mass Transfer, Vol.2, No.2, pp. 1-14, 2011, DOI:10.5098/hmt.v2.2.3002

    Abstract The stability of free convection in an annulus is governed by the boundary conditions on the inner and outer walls of the annulus and the upper and lower boundaries. This paper explores the effect of free convection on the inner surface of the annulus, where the boundary conditions for the outer wall and the upper and lower boundaries are controlled. The temperature is measured in the center of the air cavity and just below the surface of the inner annular boundary. Experimental results are shown for a radius ratio of 0.40, aspect ratio of 20.7. These more recent experimental results… More >

  • Open Access

    PROCEEDINGS

    The Method of Moments for Electromagnetic Scattering Analysis Accelerated by the Polynomial Chaos Expansion in Infinite Domains

    Yujing Ma1,*, Leilei Chen2,3, Haojie Lian3,4, Zhongwang Wang2,3

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.28, No.1, pp. 1-1, 2023, DOI:10.32604/icces.2023.010585

    Abstract An efficient method of moments (MoM) based on polynomial chaos expansion(PCE) is applied to quickly calculate the electromagnetic scattering problems. The triangle basic functions are used to discretize the surface integral equations. The PCE is utilized to accelerate the MoM by constructing a surrogate model for univariate and bivariate analysis[1]. The mathematical expressions of the surrogate model for the radar cross-section (RCS) are established by considering uncertain parameters such as bistatic angle, incident frequency, and dielectric constant[2,3]. By using the example of a scattering cylinder with analytical solution, it is verified that the MoM accelerated by PCE presents a considerable… More >

  • Open Access

    ARTICLE

    An Improved Whale Optimization Algorithm for Global Optimization and Realized Volatility Prediction

    Xiang Wang1, Liangsa Wang2,*, Han Li1, Yibin Guo1

    CMC-Computers, Materials & Continua, Vol.77, No.3, pp. 2935-2969, 2023, DOI:10.32604/cmc.2023.044948

    Abstract The original whale optimization algorithm (WOA) has a low initial population quality and tends to converge to local optimal solutions. To address these challenges, this paper introduces an improved whale optimization algorithm called OLCHWOA, incorporating a chaos mechanism and an opposition-based learning strategy. This algorithm introduces chaotic initialization and opposition-based initialization operators during the population initialization phase, thereby enhancing the quality of the initial whale population. Additionally, including an elite opposition-based learning operator significantly improves the algorithm’s global search capabilities during iterations. The work and contributions of this paper are primarily reflected in two aspects. Firstly, an improved whale algorithm… More >

  • Open Access

    ARTICLE

    A New S-Box Design System for Data Encryption Using Artificial Bee Colony Algorithm

    Yazeed Yasin Ghadi1, Mohammed S. Alshehri2, Sultan Almakdi2, Oumaima Saidani3,*, Nazik Alturki3, Fawad Masood4, Muhammad Shahbaz Khan5

    CMC-Computers, Materials & Continua, Vol.77, No.1, pp. 781-797, 2023, DOI:10.32604/cmc.2023.042777

    Abstract Securing digital image data is a key concern in today’s information-driven society. Effective encryption techniques are required to protect sensitive image data, with the Substitution-box (S-box) often playing a pivotal role in many symmetric encryption systems. This study introduces an innovative approach to creating S-boxes for encryption algorithms. The proposed S-boxes are tested for validity and non-linearity by incorporating them into an image encryption scheme. The nonlinearity measure of the proposed S-boxes is 112. These qualities significantly enhance its resistance to common cryptographic attacks, ensuring high image data security. Furthermore, to assess the robustness of the S-boxes, an encryption system… More >

  • Open Access

    ARTICLE

    A Novel Approach for Image Encryption with Chaos-RNA

    Yan Hong1,2, Shihui Fang2,*, Jingming Su2, Wanqiu Xu2, Yuhao Wei2, Juan Wu2, Zhen Yang1,3,*

    CMC-Computers, Materials & Continua, Vol.77, No.1, pp. 139-160, 2023, DOI:10.32604/cmc.2023.043424

    Abstract In today’s information society, image encryption technology is crucial to protecting Internet security. However, traditional image encryption algorithms have problems such as insufficient chaotic characteristics, insufficient randomness of keys, and insecure Ribonucleic Acid (RNA) encoding. To address these issues, a chaos-RNA encryption scheme that combines chaotic maps and RNA encoding was proposed in this research. The initial values and parameters of the chaotic system are first generated using the Secure Hash Algorithm 384 (SHA-384) function and the plaintext image. Next, the Lü hyperchaotic system sequence was introduced to change the image’s pixel values to realize block scrambling, and further disturbance… More > Graphic Abstract

    A Novel Approach for Image Encryption with Chaos-RNA

  • Open Access

    PROCEEDINGS

    Robust Shape Optimization of Sound Barriers Based on Isogeometric Boundary Element Method and Polynomial Chaos Expansion

    Xuhang Lin1, Haibo Chen1,*

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.1, pp. 1-1, 2023, DOI:10.32604/icces.2023.09388

    Abstract As an important and useful tool for reducing noise, the sound barrier is of practical significance. The sound barrier has different noise reduction effects for different sizes, shapes and properties of the sound absorbing material. Liu et al. [1] have performed shape optimization of sound barriers by using isogeometric boundary element method and method of moving asymptotes (MMA). However, in engineering practice, it is difficult to determine some parameters accurately such as material properties, geometries, external loads. Therefore, it is necessary to consider these uncertainty conditions in order to ensure the rationality of the numerical calculation of engineering problems. In… More >

  • Open Access

    ARTICLE

    3D Model Encryption Algorithm by Parallel Bidirectional Diffusion and 1D Map with Sin and Logistic Coupling

    Yongsheng Hu*

    Computer Systems Science and Engineering, Vol.47, No.2, pp. 1819-1838, 2023, DOI:10.32604/csse.2023.040729

    Abstract 3D models are essential in virtual reality, game development, architecture design, engineering drawing, medicine, and more. Compared to digital images, 3D models can provide more realistic visual effects. In recent years, significant progress has been made in the field of digital image encryption, and researchers have developed new algorithms that are more secure and efficient. However, there needs to be more research on 3D model encryption. This paper proposes a new 3D model encryption algorithm, called the 1D map with sin and logistic coupling (1D-MWSLC), because existing digital image encryption algorithms cannot be directly applied to 3D models. Firstly, this… More >

  • Open Access

    ARTICLE

    Securing Healthcare Data in IoMT Network Using Enhanced Chaos Based Substitution and Diffusion

    Musheer Ahmad1, Reem Ibrahim Alkanhel2,*, Naglaa F. Soliman2, Abeer D. Algarni2, Fathi E. Abd El-Samie3, Walid El-Shafai3,4

    Computer Systems Science and Engineering, Vol.47, No.2, pp. 2361-2380, 2023, DOI:10.32604/csse.2023.038439

    Abstract Patient privacy and data protection have been crucial concerns in E-healthcare systems for many years. In modern-day applications, patient data usually holds clinical imagery, records, and other medical details. Lately, the Internet of Medical Things (IoMT), equipped with cloud computing, has come out to be a beneficial paradigm in the healthcare field. However, the openness of networks and systems leads to security threats and illegal access. Therefore, reliable, fast, and robust security methods need to be developed to ensure the safe exchange of healthcare data generated from various image sensing and other IoMT-driven devices in the IoMT network. This paper… More >

  • Open Access

    ARTICLE

    STUDY ON HEAT AND MASS TRANSFER AND NONLINEAR CHARACTERISTICS WITH THERMAL AND SOLUTAL SOURCE IN A CAVITY

    Yubing Lia , Mo Yanga,*, Jian Lib , Zhiyun Wanga

    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.11

    Abstract Thermalsolutal convection induced by mass and heat source in horizontal cavity is investigated numerically based on SIMPLE algorithm with QUICK scheme. The high-concentration heat source is placed in the square cavity, and the cavity wall is low temperature and low concentration. The smoke is used as the diffusion medium, and the flow field, temperature and concentration of the fluid under different Rayleigh number, buoyancy ratio Nc, Soret numbers and Dufour numbers are analyzed systematically. Parameter study demonstrates that heat and mass transfer of thermosolutal convection are enhanced with increasing Rayleigh number or buoyancy ratio, and the couple-diffusive interaction has a… More >

  • Open Access

    ARTICLE

    A New Multi Chaos-Based Compression Sensing Image Encryption

    Fadia Ali Khan1, Jameel Ahmed1, Suliman A. Alsuhibany2,*

    CMC-Computers, Materials & Continua, Vol.76, No.1, pp. 437-453, 2023, DOI:10.32604/cmc.2023.032236

    Abstract The advancements in technology have substantially grown the size of image data. Traditional image encryption algorithms have limited capabilities to deal with the emerging challenges in big data, including compression and noise toleration. An image encryption method that is based on chaotic maps and orthogonal matrix is proposed in this study. The proposed scheme is built on the intriguing characteristics of an orthogonal matrix. Gram Schmidt disperses the values of pixels in a plaintext image by generating a random orthogonal matrix using logistic chaotic map. Following the diffusion process, a block-wise random permutation of the data is performed using multi-chaos.… More >

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