Mathematics and Computers in Simulation最新文献_第9页

Multi-objective sand cat swarm optimization based on adaptive clustering for solving multimodal multi-objective optimization problems 基于自适应聚类的多目标沙猫群优化，用于解决多模式多目标优化问题

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-23 DOI: 10.1016/j.matcom.2024.08.022

Yanbiao Niu , Xuefeng Yan , Weiping Zeng , Yongzhen Wang , Yanzhao Niu

{"title":"Multi-objective sand cat swarm optimization based on adaptive clustering for solving multimodal multi-objective optimization problems","authors":"Yanbiao Niu , Xuefeng Yan , Weiping Zeng , Yongzhen Wang , Yanzhao Niu","doi":"10.1016/j.matcom.2024.08.022","DOIUrl":"10.1016/j.matcom.2024.08.022","url":null,"abstract":"<div><p>Multimodal multi-objective optimization problems (MMOPs) represent a highly challenging class of complex problems, characterized by the presence of several Pareto solution sets in the decision space which map to the identical Pareto-optimal front. The goal of solving MMOPs is to find multiple distinct Pareto sets to sustain a balance between good convergence and diversification of populations. In this paper, a multi-objective sand cat swarm optimization algorithm (MOSCSO) is developed to address MMOPs. In the MOSCSO algorithm, an adaptive clustering-based specific congestion distance technique is introduced to compute the level of crowdedness. This ensures an even distribution of individuals, avoiding excessive crowding in the local area. Subsequently, enhanced search-and-attack prey updating mechanisms are designed to effectively increase not only the exploration and exploitation capabilities of the algorithm but also to enhance the diversity of the swarm in both the decision space and the objective space. To verify the effectiveness of the proposed algorithm, the MOSCSO is applied to solve the CEC2019 complex multimodal benchmark function. The experimental outcomes illustrate that the proposed approach possesses excellent performance in searching for Pareto solutions compared with other algorithms. Meanwhile, the method is also employed to address the map-based distance minimization problem, which further validates the usefulness of the MOSCSO.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142058347","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}

引用次数: 0

Distributed adaptive tracking consensus control for a class of heterogeneous nonlinear multi-agent systems 一类异构非线性多代理系统的分布式自适应跟踪共识控制

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-23 DOI: 10.1016/j.matcom.2024.08.023

Yongqing Fan, Yu Zhang, Zhen Li

引用次数: 0

Strong convergence of a class of adaptive numerical methods for SDEs with jumps 有跳跃的 SDE 的一类自适应数值方法的强收敛性

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-22 DOI: 10.1016/j.matcom.2024.08.020

Cónall Kelly , Gabriel J. Lord , Fandi Sun

引用次数: 0

A compartmental model for the dynamic simulation of pandemics with a multi-phase vaccination and its application to Italian COVID-19 data 多阶段疫苗接种大流行动态模拟分区模型及其在意大利 COVID-19 数据中的应用

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-22 DOI: 10.1016/j.matcom.2024.08.011

Roy Cerqueti , Alessandro Ramponi , Sergio Scarlatti

{"title":"A compartmental model for the dynamic simulation of pandemics with a multi-phase vaccination and its application to Italian COVID-19 data","authors":"Roy Cerqueti , Alessandro Ramponi , Sergio Scarlatti","doi":"10.1016/j.matcom.2024.08.011","DOIUrl":"10.1016/j.matcom.2024.08.011","url":null,"abstract":"<div><p>We introduce a generalization of the 4 compartments SVIR epidemic model discussed in <span><span>[1]</span></span> for the first time. Our model has K+4 compartments. K-1 of these compartments represent additional subsequent vaccination stages not considered in the original SVIR model, while a further compartment accounts for dead people. We analyze the equilibrium points of the model. A time-varying parameters version of it, having <span><math><mrow><mi>K</mi><mo>=</mo><mn>3</mn></mrow></math></span> vaccination compartments, is then calibrated to Italian COVID-19 dataset. This analysis is carried out for three specific sub-periods: the first one, ranging from February 24th, 2020, up to December 26th 2020, when no vaccines were available; the second one, from the December 27th, 2020 up to December 31st, 2021, during which the Delta variant of the virus prevailed and Delta-targeted vaccination doses were administered to the population for the first time; finally, the last considered period is ranging from January 10th, 2022 up to June 3rd, 2022, and it was characterized by the diffusion of the Omicron variant. To tackle the problem of undetected infected or undetected recovered people we adopt an approach relying on different scenarios. The calibration of the model uses the property that the discrete-time version of it turns out to be explicitly solvable with respect to the parameters, hence providing a daily estimate of the involved parameters. This produces meaningful evolution patterns of the COVID-19 epidemic which allow a better understanding of the diffusive behavior of the pandemic along time. Lastly a statistical analysis of the epidemiological parameters estimators supports the non stationarity of their time series.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0378475424003136/pdfft?md5=e9dcee6e844a052f58bc0e23c0078c5e&pid=1-s2.0-S0378475424003136-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of fear and non-linear predator harvesting on a predator–prey system in presence of environmental variability 在环境多变的情况下，恐惧和非线性捕食对捕食者-猎物系统的影响

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-22 DOI: 10.1016/j.matcom.2024.08.021

Biswajit Paul , Gopal Chandra Sikdar , Uttam Ghosh

引用次数: 0

Convergence analysis of a novel high order networks model based on entropy error function 基于熵误差函数的新型高阶网络模型收敛性分析

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-21 DOI: 10.1016/j.matcom.2024.08.014

Qianru Huang , Qinwei Fan , Zhiwei Xing , Xiaofei Yang , Xingshi He

{"title":"Convergence analysis of a novel high order networks model based on entropy error function","authors":"Qianru Huang , Qinwei Fan , Zhiwei Xing , Xiaofei Yang , Xingshi He","doi":"10.1016/j.matcom.2024.08.014","DOIUrl":"10.1016/j.matcom.2024.08.014","url":null,"abstract":"<div><p>It is generally known that the error function is one of the key factors that determine the convergence, stability and generalization ability of neural networks. For most feedforward neural networks, the squared error function is usually chosen as the error function to train the network. However, networks based on the squared error function can lead to slow convergence and easily fall into local optimum in the actual training process. Recent studies have found that, compared to the squared error function, the gradient method based on the entropy error function measures the difference between the probability distribution of the model output and the probability distribution of the true labels during the iterative process, which can be more able to handle the uncertainty in the classification problem, less likely to fall into a local optimum and can learn to converge more rapidly. In this paper, we propose a batch gradient method for Sigma-Pi-Sigma neural networks based on the entropy error function and rigorously demonstrate the weak and strong convergence of the new algorithm in the batch input mode. Finally, the theoretical results and effectiveness of the algorithm are verified by simulation.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142075979","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}

引用次数: 0

Canard cycle and nonsmooth bifurcation in a piecewise-smooth continuous predator-prey model 片状光滑连续捕食者-猎物模型中的卡纳德循环和非光滑分岔

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-20 DOI: 10.1016/j.matcom.2024.08.017

Zirui Zhu , Xingbo Liu

{"title":"Canard cycle and nonsmooth bifurcation in a piecewise-smooth continuous predator-prey model","authors":"Zirui Zhu , Xingbo Liu","doi":"10.1016/j.matcom.2024.08.017","DOIUrl":"10.1016/j.matcom.2024.08.017","url":null,"abstract":"<div><p>This article establishes a bifurcation analysis of a singularly perturbed piecewise-smooth continuous predator–prey system with a sufficiently small parameter. The bifurcation that can generate limit cycles here is our main concern. To achieve this goal, we have developed a lemma that is used to determine the parameter region that can generate limit cycles. Further conclusions indicate that the existence of a 2-shaped critical manifold is required. Based on the Poincaré-Bendixon lemma, Fenichel’s theory and geometric singular perturbation theory, we demonstrate the possibility of generating smooth and nonsmooth bifurcations. In fact, nonsmooth bifurcations only occur in piecewise-smooth systems. More specifically, different types of nonsmooth bifurcations are also presented in this article, including nonsmooth Hopf bifurcation, Hopf-like bifurcation and super-explosion. In addition, this article discusses the existence of crossing limit cycles and explains whether the crossing limit cycle is characterized by canard cycles without head, canard cycles with head or relaxation oscillations. Furthermore, the coexistence of two relaxation oscillations, the coexistence of two canard cycles without head, and the coexistence of one relaxation oscillation and one canard cycle without head are investigated. Moreover, the one-parameter bifurcation diagram is also presented in this paper through numerical simulations.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142083499","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}

引用次数: 0

Modelling the comparative influence of conjugation and transformation on plasmid spread in biofilms 模拟共轭和转化对质粒在生物膜中传播的比较影响

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-20 DOI: 10.1016/j.matcom.2024.08.018

Julien Vincent , Alberto Tenore , Maria Rosaria Mattei , Luigi Frunzo

{"title":"Modelling the comparative influence of conjugation and transformation on plasmid spread in biofilms","authors":"Julien Vincent , Alberto Tenore , Maria Rosaria Mattei , Luigi Frunzo","doi":"10.1016/j.matcom.2024.08.018","DOIUrl":"10.1016/j.matcom.2024.08.018","url":null,"abstract":"<div><p>In this work, we propose a multidimensional continuum model for plasmid dissemination in biofilms via horizontal gene transfer. The model is formulated as a system of nonlocal partial differential equations derived from mass conservation laws and reaction kinetics principles. Biofilm is modelled as a homogeneous, viscous, incompressible fluid with a velocity given by Darcy’s law. The model considers plasmid-carrying cells as distinct volume fractions and their vertical and horizontal gene transfer via conjugation and natural transformation. The model encompasses local detoxification of biofilm due to plasmid-borne resistance gene and its effect at the community scale. The equations are solved numerically and simulations are performed to investigate how transformation and conjugation regulate the dynamics and the ecology of plasmid spread in both a multidimensional and one-dimensional biofilm system. Model results are able to predict relevant experimentally observed results in plasmid spread, such as the respective intensity of different horizontal gene transfer mechanisms and the importance of selective pressure. Moreover, model results predict coexistence of plasmid-carrying and plasmid-free bacteria even in conditions when one should out-compete the other, offering a simple modelling explanation on global plasmid persistence in bacterial communities.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0378475424003203/pdfft?md5=e7ff43680b5d4c4c9620aedc92a8950f&pid=1-s2.0-S0378475424003203-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dimension reduction for Quasi-Monte Carlo methods via quadratic regression 通过二次回归降低准蒙特卡罗方法的维度

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-17 DOI: 10.1016/j.matcom.2024.08.016

Junichi Imai , Ken Seng Tan

{"title":"Dimension reduction for Quasi-Monte Carlo methods via quadratic regression","authors":"Junichi Imai , Ken Seng Tan","doi":"10.1016/j.matcom.2024.08.016","DOIUrl":"10.1016/j.matcom.2024.08.016","url":null,"abstract":"<div><p>Quasi-Monte Carlo (QMC) methods have been gaining popularity in computational finance as they are competitive alternatives to Monte Carlo methods that can accelerate numerical accuracy. This paper develops a new approach for reducing the effective dimension combined with a randomized QMC method. A distinctive feature of the proposed approach is its sample-based transformation that enables us to choose a flexible manipulation via regression. In the proposed approach, the first step is to perform a regression using the samples to estimate the parameters of the regression model. An optimal transformation is proposed based on the regression result to minimize the effective dimension. An advantage of this approach is that adopting a statistical approach allows greater flexibility in selecting the regression model. In addition to a linear model, this paper proposes a dimension reduction method based on a linear-quadratic model for regression. In numerical experiments, we focus on pricing different types of exotic options to test the effectiveness of the proposed approach. The numerical results show that different regression models are chosen depending on the underlying risk process and the type of derivative securities. In particular, we show several examples where the proposed method works while existing dimension reductions are ineffective.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0378475424003185/pdfft?md5=faa81dfc482a8f8a1e66a2e0a08e568e&pid=1-s2.0-S0378475424003185-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142049993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamic complexities in a predator–prey model with prey refuge influenced by double Allee effects 受双重阿利效应影响的捕食者-猎物模型中猎物避难所的动态复杂性

IF 4.4 2区数学

Mathematics and Computers in Simulation Pub Date : 2024-08-17 DOI: 10.1016/j.matcom.2024.08.015

Gourav Mandal , Lakshmi Narayan Guin , Santabrata Chakravarty , Renji Han

{"title":"Dynamic complexities in a predator–prey model with prey refuge influenced by double Allee effects","authors":"Gourav Mandal , Lakshmi Narayan Guin , Santabrata Chakravarty , Renji Han","doi":"10.1016/j.matcom.2024.08.015","DOIUrl":"10.1016/j.matcom.2024.08.015","url":null,"abstract":"<div><p>Within the context of a two-dimensional framework encompassing interacting species, an examination is conducted in this study on the double Allee effect and prey refuge, considering both species in the interaction. The stability of the feasible equilibrium of the system and diverse bifurcation patterns including codimension-one and codimension-two bifurcations are scrutinized through theoretical and numerical investigations, which reveals the complex dynamics induced by saturated functional response and double Allee effects. Additionally, one-parameter bifurcation diagrams and two-parameter bifurcation diagrams are constructed to intricately evaluate the system’s dynamics indicative of the presence of multiple attractors like bi-stability and tri-stability. Lastly, the sensitivity analysis is performed to delve into the effect of system parameters on species density, which indicates that the parameter <span><math><mi>η</mi></math></span> proportional to the conversion rate is the most sensitive parameter. A brief discussion further reveals that the model without double Allee effect reduces dynamic complexity.</p></div>","PeriodicalId":49856,"journal":{"name":"Mathematics and Computers in Simulation","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142096965","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}

引用次数: 0