Mathematics and Computers in Simulation最新文献

{"title":"Minimax concave penalty-based TGV model for Poissonian image restoration","authors":"Xinwu Liu ,&nbsp;Xiang Yu ,&nbsp;Jiangli Liang","doi":"10.1016/j.matcom.2025.05.001","DOIUrl":"10.1016/j.matcom.2025.05.001","url":null,"abstract":"<div><div>As is known to all, although the denoising models based on total generalized variation regularization prevent the occurrence of staircase artifacts, they also tend to result in blurred edges in the restored images. In order to obtain high-quality images that conform human visual characteristics, we add a minimax concave penalty into the total generalized variation function, and develop a novel Kullback–Leibler divergence fidelity-based model for Poissonian image restoration. By integrating the variable splitting technique, a modified alternating direction method of multipliers is designed for numerical computation. Moreover, under proper parameter selection, the convergence of our proposed algorithm is established in detail. As the experimental validations, we have conducted a variety of numerical experiments comparing our new solver with some existing state-of-the-art methods. From the numerical experiments, it follows that our approach can not only preserve structural features well, but also achieve comparable recovery effects over other denoising schemes.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"238 ","pages":"Pages 25-44"},"PeriodicalIF":4.4,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the risk of mosquito-borne diseases in non-endemic regions: A dynamic modeling approach","authors":"Nico Stollenwerk ,&nbsp;Luís Mateus ,&nbsp;Vanessa Steindorf ,&nbsp;Bruno V. Guerrero ,&nbsp;Rubén Blasco-Aguado ,&nbsp;Aitor Cevidanes ,&nbsp;Joseba Bidaurrazaga Van-Dierdonck ,&nbsp;Maíra Aguiar","doi":"10.1016/j.matcom.2025.04.026","DOIUrl":"10.1016/j.matcom.2025.04.026","url":null,"abstract":"<div><div>Mosquito-borne diseases are spreading into temperate zones, raising concerns about local outbreaks driven by imported cases. Using stochastic methods, we developed a vector-host model to estimate the risk of import-driven autochthonous outbreaks in non-endemic regions. The model explores key factors such as imported cases and vector abundance. Our analysis shows that mosquito population abundance significantly affects the probability and timing of outbreaks. Even with moderate mosquito populations, isolated or clustered outbreaks can be triggered, highlighting the importance of monitoring vector abundance for effective public health planning and interventions.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"238 ","pages":"Pages 1-24"},"PeriodicalIF":4.4,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Limit cycles of homogeneous polynomial Kukles differential systems","authors":"Jaume Giné ,&nbsp;Joan Torregrosa","doi":"10.1016/j.matcom.2025.04.045","DOIUrl":"10.1016/j.matcom.2025.04.045","url":null,"abstract":"<div><div>We study the number of limit cycles which can bifurcate from the periodic orbits of the harmonic oscillator when it is perturbed by homogeneous polynomials of degree <span><math><mi>n</mi></math></span>, only in the second differential equation, which corresponds to the so-called Kukles systems. Moreover, the degenerate Hopf bifurcation is also studied for such systems.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 335-343"},"PeriodicalIF":4.4,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143949030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Voltage reference varying-based adaptive IDA-PBC design and stability analysis for DC microgrids","authors":"Cong Yuan ,&nbsp;Jean-Philippe Martin ,&nbsp;Serge Pierfederici ,&nbsp;Matheepot Phattanasak ,&nbsp;Farid Meibody-Tabar ,&nbsp;Shengzhao Pang","doi":"10.1016/j.matcom.2025.04.028","DOIUrl":"10.1016/j.matcom.2025.04.028","url":null,"abstract":"<div><div>Constant Power Loads (CPLs), which are widely present in DC microgrids, exhibit negative impedance characteristics, reducing the system’s stability margin and posing significant challenges to grid control and stability. To address this issue, we propose an Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) strategy. By reshaping system energy and injecting damping, the proposed controller ensures the attainment of the desired equilibrium point and dynamic performance, thereby enhancing the microgrid’s stability margin. Unlike conventional IDA-PBC methods, which typically modify the interconnection matrix by introducing a parameter <span><math><mi>K</mi></math></span> to obtain a unique control law solution, our approach achieves a unique solution by redefining the reference voltage. This strategy effectively eliminates singularity issues at the equilibrium point. Furthermore, we conduct a comprehensive stability analysis of the proposed IDA-PBC, derive the system’s stability margin, and design a trajectory-tracking controller to validate its advantages in improving stability. Finally, numerical simulations and experiments are performed to verify both the effectiveness of the proposed controller and the accuracy of the stability analysis.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 355-372"},"PeriodicalIF":4.4,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Image hiding algorithm based on local binary pattern and compressive sensing","authors":"Guodong Ye ,&nbsp;Shoukang Liu ,&nbsp;Xiuchun Xiao ,&nbsp;Xiaoling Hunag","doi":"10.1016/j.matcom.2025.05.005","DOIUrl":"10.1016/j.matcom.2025.05.005","url":null,"abstract":"<div><div>In recent years, with the rapid growth of digital communication, the protection of image privacy has become a critical concern. Traditional image encryption methods may attract attacker attention due to the noise-like appearance of cipher image. To address the theft risk to the private image, a novel three-dimensional chaotic map of Chebyshev coupled Logistic with Sine map (3D-CCLSM) is designed, and then an image hiding algorithm based on local binary pattern (LBP) and compressive sensing (CS) is proposed, named ImHALC. By integrating LBP-based texture feature extraction and CS-based image compression, ImHALC aims to enhance both the security and imperceptibility for steganographic image. Especially, LBP is taken to connect the plain image and keystream, resulting a high security for ImHALC. Firstly, in stage of keystream generation, texture information of the plain image is extracted by using LBP and seen as input of hash function SHA-256, to produce corresponding hash values. Then, these hash values are used to generate the initial value of 3D-CCLSM by a new designed key transformation model (KAM), so as to get the keystream for encryption. Secondly, in stage of image compression, a measurement matrix is constructed by above keystream, and CS is applied to the plain image to get measurements. Thirdly, in stage of image encryption, measurements are confused and diffused to produce a cipher image. Finally, in stage of embedding, an embedding method using integer wavelet transformation (IWT) and 2^k correction is presented, so as to embed the secrets (i.e., cipher image) into a given carrier image to obtain hiding performance, i.e., forming a carrier image hiding secrets (CHS). In particular, the ImHALC can achieve the effect of blind extraction. After adopting a two-dimensional projection gradient algorithm with embedded decryption (2DPG-ED), the reconstruction quality for the plain image is good for test images.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 316-334"},"PeriodicalIF":4.4,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An optimal and efficient framework for the construction of nonlinear components based on a polynomial ring","authors":"Ch Muhammad Afaq Aslam ,&nbsp;Ikram Ullah ,&nbsp;Muhammad Ishaq","doi":"10.1016/j.matcom.2025.04.022","DOIUrl":"10.1016/j.matcom.2025.04.022","url":null,"abstract":"<div><div>The widespread use of internet makes it essential to protect the private data from the intruders via developing highly secure cryptographic systems. The Substitution box (s-box) is the only nonlinear component of any security system. It plays a crucial role in securing data from an unauthorized access by inverting it into an unreadable form. The algebraic structures are mostly utilized to develop two types of s-box generators, namely the randomized and the optimal generators. The one type outputs dynamic, while the other one is responsible to design s-boxes with high cryptographic properties. However, the generator which gives highly dynamic and optimal s-boxes needs high computational overhead, which limits the encryption throughput of a large useful data set. This fact implies the need of developing an s-box generator that is capable to construct an s-box with high cryptographic properties at a low computational cost. This study presents an innovative algebraic method for constructing optimal s-boxes using a finite field and a polynomial ring. Our approach offers flexibility in selecting unconstrained primes and polynomials, allowing the generation of highly dynamic and nonlinear s-boxes. By evaluating polynomials over a finite field and introducing a new total ordering, we effectively diffuse input elements and derive optimal s-boxes with a nonlinearity of 112. We determine the total number of s-boxes based on the proposed scheme. The performance of the proposed s-box is assessed using standard metrics. We compare the attained results with that of the s-boxes constructed by the recent and state of the art algorithms. Apart from this, we compare the proposed s-box generator with an efficient one regarding the execution time and other cryptographic properties. We showed that the proposed scheme attains the highly nonlinear component approximately 5 times faster than the existing one, and the experimental results indicate that the current method outperforms than others across the standard cryptographic metrics.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 263-280"},"PeriodicalIF":4.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel BDF-spectral method and its error analysis for Cahn–Hilliard equation in polar geometry","authors":"Jihui Zheng,&nbsp;Zhenlan Pan,&nbsp;Jing An","doi":"10.1016/j.matcom.2025.04.023","DOIUrl":"10.1016/j.matcom.2025.04.023","url":null,"abstract":"<div><div>In this paper, we first propose and study a finite difference Legendre-Fourier spectral method for solving the Cahn–Hilliard equation in polar geometry. The fundamental idea is to restate the original problem in an equivalent form under polar coordinates. Subsequently, by introducing an auxiliary second-order equation, we transform it into a coupled second-order nonlinear system. Furthermore, we introduce a class of weighted Sobolev spaces and their approximation spaces, formulate first- and second-order semi-implicit schemes for the coupled second-order nonlinear system, and demonstrate the stability of these schemes under specific conditions on the time step. In particular, the introduction of pole singularities and the nonlinearity of coupling problem pose significant challenges to theoretical analysis. To overcome these difficulties, we construct a new class of projection operators and prove their approximation properties, thereby providing error estimates for the approximate solutions. Finally, we provide numerous numerical examples, and the numerical results confirm the effectiveness of the algorithm and the correctness of the theoretical findings.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 145-166"},"PeriodicalIF":4.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enriched physics-informed neural networks for dynamic Poisson-Nernst-Planck systems","authors":"Xujia Huang ,&nbsp;Fajie Wang ,&nbsp;Benrong Zhang ,&nbsp;Hanqing Liu","doi":"10.1016/j.matcom.2025.04.037","DOIUrl":"10.1016/j.matcom.2025.04.037","url":null,"abstract":"<div><div>This paper proposes a meshless deep learning algorithm, called enriched physics-informed neural networks (EPINNs), to solve dynamic Poisson-Nernst-Planck (PNP) equations characterized by strong coupling and nonlinear behaviors. EPINNs build upon traditional physics-informed neural networks (PINNs) by incorporating an adaptive loss weight mechanism, which automatically adjusts the weights of the loss functions during training, based on maximum likelihood estimation, to achieve balanced optimization. Additionally, a resampling strategy is introduced to accelerate the convergence of the loss function. Four numerical examples are presented to demonstrate the validity and effectiveness of the proposed method. The results show that EPINNs have better applicability than traditional numerical methods in solving such coupled nonlinear systems. Furthermore, EPINNs outperform traditional PINNs in terms of accuracy, stability, and speed. This work provides a robust and efficient numerical tool for solving PNP equations with arbitrary boundary shapes and conditions.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 231-246"},"PeriodicalIF":4.4,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel time-fractional decomposition model for image denoising integrating Caputo derivative","authors":"Z. Zaabouli,&nbsp;L. Afraites,&nbsp;A. Laghrib","doi":"10.1016/j.matcom.2025.04.013","DOIUrl":"10.1016/j.matcom.2025.04.013","url":null,"abstract":"<div><div>In this work, we tackle the persistent problem of image restoration by developing a novel model that integrates a Caputo time fractional derivative into a reaction–diffusion framework. This approach exploits the memory effect of fractional derivatives for better diffusion control. With a thorough analysis employing the <em>H^-1</em> norm decomposition strategy and the Weickert filter, our model excels in noise reduction and image quality preservation. The task of establishing solution existence and uniqueness was managed using the fixed point method. The results reveal substantial improvements in denoising performance, highlighting the model’s potential.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 1-17"},"PeriodicalIF":4.4,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the computational modeling of the behavior of a three-dimensional Brusselator system using a localized meshless method","authors":"Manzoor Hussain ,&nbsp;Abdul Ghafoor","doi":"10.1016/j.matcom.2025.04.020","DOIUrl":"10.1016/j.matcom.2025.04.020","url":null,"abstract":"<div><div>Nonlinear coupled reaction–diffusion equations form an important class of partial differential equations (PDEs) as they are central to the study of certain processes arising in chemical kinetics and biochemical reactions. The analytical solutions of such equations are difficult to establish and often require certain simplified assumptions, which demand for alternative solution procedures. Finite difference, finite element and spectral schemes are well-established methods to tackle such equations, yet they have the challenging issues of mesh generation, underlying integral evaluations, ill-conditioned dense system matrices, and are often restricted by domain geometry. This article presents an efficient and simple localized meshless approximation scheme to analyze the solution behavior of a three-dimensional reaction–diffusion system. The proposed scheme produces sparse (collocation) differentiation matrices for discretization of spatial differential operators which alleviates the problem of ill-conditioned and dense collocation matrices. The scheme is a truly meshless, background integration-free scheme and is equally effective for solving problems over non-rectangular domains with scattered data points. The convergence, stability, and positivity properties of the proposed scheme are theoretically established and numerically verified on some benchmark problems. The outcomes verify the reliability, accuracy, and simplicity of the proposed scheme in higher dimensions when compared to the available results in the literature.</div></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":"237 ","pages":"Pages 18-41"},"PeriodicalIF":4.4,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}