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Mathematical Modeling and Analysis on the Effects of Surgery and Chemotherapy on Lung Cancer 肺癌手术与化疗效果的数学建模与分析
Pub Date : 2023-06-23 DOI: 10.1155/2023/4201373
Md. Ahsan Ullah, Uzzwal Kumar Mallick
Lung cancer is the biggest cause of cancer mortality worldwide and a major impediment to extending life expectancy. In comparison to other cancers, it has a relatively poor survival rate. In this paper, we have developed a mathematical model for lung cancer based on biological phenomena using nonlinear ordinary differential equations and analyzed it both analytically and numerically. According to the findings, CD8+ T cells and dendritic cells have a role in tumor cell variety. Surgery and chemotherapy have been used as treatment options, and we have observed that three doses of chemotherapy after surgery had the greatest results after examining several treatment options. During the treatment period, the cycle of each chemotherapy has been taken every 4 weeks, and the first dose has been taken after 28 days of surgery. Finally, we have evaluated the various starting dates for the best treatment choice and discovered that the patient who begins treatment sooner has a better probability of surviving.
肺癌是全球癌症死亡的最大原因,也是延长预期寿命的主要障碍。与其他癌症相比,它的存活率相对较低。本文利用非线性常微分方程建立了基于生物现象的肺癌数学模型,并对其进行了解析和数值分析。根据研究结果,CD8+ T细胞和树突状细胞在肿瘤细胞的多样性中起作用。手术和化疗已被用作治疗方案,我们观察到,在检查了几种治疗方案后,手术后三次化疗的效果最好。治疗期间,每4周进行一次化疗周期,手术28天后进行第一次化疗。最后,我们评估了最佳治疗选择的各种开始日期,发现越早开始治疗的患者存活的可能性越大。
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引用次数: 0
An Alternative Method for Analytical Solutions of Two-Dimensional Black-Scholes-Merton Equation 二维Black-Scholes-Merton方程解析解的一种替代方法
Pub Date : 2023-06-21 DOI: 10.1155/2023/6725686
Jun Yu, Michael J. Tomas
We present a method of deriving analytical solutions for a two-dimensional Black-Scholes-Merton equation. The method consists of three changes of variables in order to reduce the original partial differential equation (PDE) to a normal form and then solve it. Analytical solutions for two cases of option pricing on the minimum and maximum of two assets are derived using our method and are shown to agree with previously published results. The advantage of our solution procedure is the ability of splitting the original problem into several components in order to demonstrate some solution properties. The solutions of the two cases have a total of five components; each is a particular solution of the PDE itself. Due to the linearity of the two-dimensional Black-Scholes-Merton equation, any linear combination of these components constitutes another solution. Some other possible solutions as well as the solution properties are discussed.
给出了二维Black-Scholes-Merton方程解析解的一种推导方法。该方法通过三次变量变换,将原偏微分方程化为标准形式并求解。用我们的方法推导了两种资产的最小和最大期权定价的两种情况的解析解,并显示与先前发表的结果一致。我们的解决方案过程的优点是能够将原始问题分解为几个组件,以便演示一些解决方案的属性。这两种情况的解共有五个组成部分;每一个都是偏微分方程本身的特解。由于二维布莱克-斯科尔斯-默顿方程的线性,这些分量的任何线性组合都构成另一个解。讨论了其他可能的解及其性质。
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引用次数: 0
Mathematical Optimization on Hybrid Channel Pricing Digital Products in Two-Sided Market with Network Effect 网络效应下双边市场数字产品混合渠道定价的数学优化
Pub Date : 2023-05-27 DOI: 10.1155/2023/4456931
W. Li, Yan-peng He, Shuangbao Ma
In the two-sided market where the third-party platforms connect the providers and consumers, the online platforms become the significant distribution channel of digital products; therefore, the digital product firms face the hybrid channel pricing problem in the two-sided market in which the products are launched through the platform channel and the existing direct channel. Because the network externality effect is the significant economic characteristic of digital products and services, the current work presents the models of consumers’ utility obtained by adopting digital products from the direct and platform channels, and the utility models use the network effect in the direct and platform channels as the parameters. The optimization model on pricing is derived from the utility models and solved mathematically. The closed-form solutions show that the price in the direct channel is supposed to be lower than that in the platform channel, while the prices of digital products would be affected by the network effect only when the products are distributed through the direct channel. The comparative statics analysis on the network effect illustrates that the network effect in the direct channel and the platform channel would, respectively, have the positive and negative impact on the products’ prices and the firms’ profit. The current work explores the hybrid channel pricing problem and provides insights for the digital product firms on the optimal pricing decision in the context of the emerging platform economy.
在第三方平台连接供应商和消费者的双边市场中,在线平台成为数字产品的重要分销渠道;因此,数字产品企业在通过平台渠道和现有直接渠道推出产品的双边市场中,面临着混合渠道定价问题。由于网络外部性效应是数字产品和服务的重要经济特征,因此,本文提出了采用直接渠道和平台渠道的数字产品所获得的消费者效用模型,实用新型以直接渠道和平台渠道中的网络效应作为参数。根据本实用新型导出了定价优化模型,并进行了数学求解。封闭形式的解表明,直接渠道的价格应该低于平台渠道的价格,而数字产品的价格只有在通过直接渠道分销时才会受到网络效应的影响。对网络效应的比较统计分析表明,直销渠道和平台渠道的网络效应分别对产品价格和企业利润产生积极和消极的影响。本文探讨了混合渠道定价问题,并为数字产品公司在新兴平台经济背景下的最优定价决策提供了见解。
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引用次数: 0
Error Bounds for Approximations Using Multichannel Deep Convolutional Neural Networks with Downsampling 带下采样的多通道深度卷积神经网络逼近误差界
Pub Date : 2023-05-18 DOI: 10.1155/2023/8208424
Xinling Liu, Jingyao Hou
Deep learning with specific network topologies has been successfully applied in many fields. However, what is primarily called into question by people is its lack of theoretical foundation investigations, especially for structured neural networks. This paper theoretically studies the multichannel deep convolutional neural networks equipped with the downsampling operator, which is frequently used in applications. The results show that the proposed networks have outstanding approximation and generalization ability of functions from ridge class and Sobolev space. Not only does it answer an open and crucial question of why multichannel deep convolutional neural networks are universal in learning theory, but it also reveals the convergence rates.
具有特定网络拓扑结构的深度学习已经成功地应用于许多领域。然而,人们主要质疑的是其缺乏理论基础研究,特别是对结构化神经网络的研究。本文从理论上研究了应用中常用的带下采样算子的多通道深度卷积神经网络。结果表明,该网络对岭类和Sobolev空间的函数具有较好的逼近和泛化能力。它不仅回答了一个开放而关键的问题,即为什么多通道深度卷积神经网络在学习理论中是普遍的,而且它还揭示了收敛速度。
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引用次数: 0
Exact Nonlinear Spectral Analysis of Nonsmooth WENO-JS Solutions 非光滑WENO-JS解的精确非线性谱分析
Pub Date : 2023-05-10 DOI: 10.1155/2023/4941679
T. Kasem
The fifth-order accurate Weighted Essentially Nonoscillatory space discretization developed by Jiang and Shu (WENO-JS) is studied theoretically. An exact Nonlinear Spectral Method (NSM) is developed based on an innovative yet simple methodology. The NSM explains the behaviour of nonsmooth solutions because it is valid for arbitrary modified wave numbers (MWN). The NSM clarifies the effects of the time integration methods and the Courant number. The mode isolation assumption, extensively used to analyse WENO-JS, is elucidated, and several novel findings are presented. The improved performance of the combination of WENO-JS with the forward Euler time integration method, compared to the Linear Fifth-Order Upwind discretization, is illustrated. The overdamping of the combination of WENO-JS with the popular third-order total variation diminishing Runge-Kutta method is discovered. Thus, the NSM covers several gaps in the current literature.
对Jiang和Shu提出的五阶精确加权本质非振荡空间离散化(WENO-JS)进行了理论研究。基于一种新颖而简单的方法,提出了一种精确的非线性谱法。NSM解释了非光滑解的行为,因为它对任意修正波数(MWN)有效。NSM阐明了时间积分方法和科朗数的影响。模态隔离假设,广泛用于分析WENO-JS,被阐明,并提出了一些新的发现。与线性五阶迎风离散相比,WENO-JS与正演欧拉时间积分方法相结合的性能得到了改善。发现了WENO-JS与流行的三阶全变分递减龙格-库塔法组合时的过阻尼问题。因此,NSM涵盖了当前文献中的几个空白。
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引用次数: 0
Modeling Cholera Epidemiology Using Stochastic Differential Equations 用随机微分方程模拟霍乱流行病学
Pub Date : 2023-05-09 DOI: 10.1155/2023/7232395
W. Iddrisu, Inusah D. Iddrisu, Abdul-Karim Iddrisu
In this study, we extend Codeço’s classical SI-B epidemic and endemic model from a deterministic framework into a stochastic framework. Then, we formulated it as a stochastic differential equation for the number of infectious individuals I t under the role of the aquatic environment. We also proved that this stochastic differential equation (SDE) exists and is unique. The reproduction number, R 0 , was derived for the deterministic model, and qualitative features such as the positivity and invariant region of the solution, the two equilibrium points (disease-free and endemic equilibrium), and stabilities were studied to ensure the biological meaningfulness of the model. Numerical simulations were also carried out for the stochastic differential equation (SDE) model by utilizing the Euler-Maruyama numerical method. The method was used to simulate the sample path of the SI-B stochastic differential equation for the number of infectious individuals I t , and the findings showed that the sample path or trajectory of the stochastic differential equation for the number of infectious individuals I t is continuous but not differentiable and that the SI-B stochastic differential equation model for the number of infectious individuals I t fluctuates inside the solution of the SI-B ordinary differential equation model. Another significant feature of our proposed SDE model is its simplicity.
在本研究中,我们将codecadeo经典的SI-B流行病和地方病模型从确定性框架扩展到随机框架。然后,我们将其表述为在水生环境作用下感染个体数I t的随机微分方程。并证明了该随机微分方程的存在性和唯一性。推导了确定性模型的繁殖数r0,并研究了解的正性和不变区、两个平衡点(无病平衡点和地方病平衡点)和稳定性等定性特征,以确保模型的生物学意义。采用Euler-Maruyama数值方法对随机微分方程(SDE)模型进行了数值模拟。用该方法模拟感染个体数I t的SI-B随机微分方程的样本路径;结果表明,感染个体数随机微分方程的样本路径或轨迹是连续的但不可微的,感染个体数的SI-B随机微分方程模型在SI-B常微分方程模型的解内波动。我们提出的SDE模型的另一个重要特征是它的简单性。
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引用次数: 0
Interaction of Two Rigid Spheres Oscillating in an Infinite Liquid under the Control of a Magnetic Field 磁场控制下在无限液体中振荡的两个刚性球体的相互作用
Pub Date : 2023-05-05 DOI: 10.1155/2023/1146872
Shreen El-Sapa, W. Albalawi
The transient creeping motion of two rigid spheres oscillating in a boundless viscous fluid beneath the impact of the magnetic field is investigated. There is no slippage associated with a Stokes flow on the two rigid spherical surfaces with different sizes and radii. The solutions can be obtained using the boundary collocation scheme at low Reynolds numbers. The unsteady real and imaginary drag coefficients are estimated on the hard spherical particles. These coefficients are computed in tables for various parameters and illustrated graphically. The frequency parameter and Hartmann number also play a significant role in this study where the drag coefficients decrease or increase by 100 percent after the value of κ = 5.0 . Using available literature data, we tested the accuracy and reliability of our results.
研究了在无边界粘性流体中振荡的两个刚性球体在磁场作用下的瞬态蠕动运动。在两个不同尺寸和半径的刚性球面上,不存在与斯托克斯流相关的滑移。在低雷诺数条件下,可以采用边界配置格式求解。对硬球形颗粒的非定常实阻力系数和虚阻力系数进行了估计。这些系数在各种参数的表中计算出来,并用图形说明。频率参数和Hartmann数在本研究中也发挥了重要作用,当κ = 5.0时,阻力系数减小或增大100%。利用现有文献资料,我们检验了结果的准确性和可靠性。
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引用次数: 1
Hydromagnetic Flow of Two Immiscible Couple Stress Fluids through Porous Medium in a Cylindrical Pipe with Slip Effect 带滑移效应的两种不混相耦合应力流体在圆柱管中通过多孔介质的磁流
Pub Date : 2023-05-03 DOI: 10.1155/2023/1902844
Punnamchandar Bitla, Yitagesu Daba Kore
In this study, the steady hydromagnetic flow of two immiscible couple stress fluids through a uniform porous medium in a cylindrical pipe with slip effect is investigated analytically. Essentially, the flow system is divided into two regions, region I and region II, which occupy the core and periphery of the system, respectively. The flow is driven by a constant pressure gradient applied in a direction parallel to the cylinder’s axis, and an external uniform magnetic field is applied in the direction perpendicular to the direction of fluid motion. Instead of the classical no-slip condition, the slip velocity along with vanishing couple stress boundary conditions is taken on the surface of the rigid cylinder, and continuity conditions of velocity, vorticity, shear stress, and couple stress are imposed at the fluid-fluid interface. The governing equations are modeled using the fully developed flow conditions. The resulting differential equations governing the flow in the two regions are converted to nondimensional forms using appropriate dimensionless variables. The nondimensional equations are solved analytically, and closed-form expressions for the flow velocity, flow rate, and stresses are derived in terms of the Bessel functions. The impacts of several parameters pertaining to the flow such as the magnetic number, couple stress parameters, Darcy number, viscosity ratio, Reynolds number, and slip parameter on the velocities in respective regions are examined and illustrated through graphs. The flow rate’s numerical values are also calculated for different fluid parameters and displayed in tabular form. It is found that increasing the magnetic number, viscosity ratio, Reynolds number, and slip parameters decreases the velocities of the fluids whereas increasing the couple stress parameter, Darcy number, and pressure gradient increases fluid velocities. The results obtained in this paper show an excellent agreement with the already existing results in the literature as limiting cases.
本文分析研究了两种不混相耦合应力流体在均匀多孔介质中具有滑移效应的圆柱形管道中的稳态磁流体流动。从本质上讲,流动系统分为两个区域,区域I和区域II,分别占据系统的核心和外围。在平行于圆筒轴线方向上施加恒定压力梯度,并在垂直于流体运动方向的方向上施加外部均匀磁场,驱动流体流动。代替经典的无滑移条件,在刚性圆柱体表面取滑移速度和消失耦合应力边界条件,在流体-流体界面处施加速度、涡度、剪切应力和耦合应力的连续性条件。控制方程采用充分开发的流动条件进行建模。使用适当的无量纲变量将控制两个区域内流动的微分方程转换为无量纲形式。对无量纲方程进行了解析求解,导出了流速、流量和应力的贝塞尔函数封闭表达式。考察了磁数、耦合应力参数、达西数、黏度比、雷诺数、滑移参数等与流动有关的几个参数对相应区域速度的影响,并用图形说明了这些影响。计算了不同流体参数下的流量数值,并以表格形式显示。结果表明,增大磁数、黏度比、雷诺数和滑移参数会降低流体的速度,增大耦合应力参数、达西数和压力梯度会增大流体的速度。本文所得到的结果与已有文献中作为极限情况的结果非常吻合。
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引用次数: 0
A Fast and Efficient Estimation of the Parameters of a Model of Accident Frequencies via an MM Algorithm 基于MM算法的事故频率模型参数快速有效估计
Pub Date : 2023-04-19 DOI: 10.1155/2023/3377201
Issa Cherif Geraldo, Edoh Katchekpele, T. A. Kpanzou
In this paper, we consider a multivariate statistical model of accident frequencies having a variable number of parameters and whose parameters are dependent and subject to box constraints and linear equality constraints. We design a minorization-maximization (MM) algorithm and an accelerated MM algorithm to compute the maximum likelihood estimates of the parameters. We illustrate, through simulations, the performance of our proposed MM algorithm and its accelerated version by comparing them to Newton-Raphson (NR) and quasi-Newton algorithms. The results suggest that the MM algorithm and its accelerated version are better in terms of convergence proportion and, as the number of parameters increases, they are also better in terms of computation time.
在本文中,我们考虑了一个具有可变数量参数的事故频率的多元统计模型,该模型的参数是相关的,并受盒形约束和线性等式约束。我们设计了一个最小化最大化(MM)算法和一个加速的MM算法来计算参数的最大似然估计。我们通过仿真来说明我们提出的MM算法及其加速版本的性能,并将它们与Newton-Raphson (NR)和准牛顿算法进行比较。结果表明,MM算法及其加速版本在收敛比例上更胜一筹,并且随着参数数量的增加,其计算时间也更胜一筹。
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引用次数: 1
Network Model with Scale-Free, High Clustering Coefficients, and Small-World Properties 具有无标度、高聚类系数和小世界性质的网络模型
Pub Date : 2023-04-17 DOI: 10.1155/2023/5533260
Chuankui Yan
Networks are prevalent in real life, and the study of network evolution models is very important for understanding the nature and laws of real networks. The distribution of the initial degree of nodes in existing classical models is constant or uniform. The model we proposed shows binomial distribution, and it is consistent with real network data. The theoretical analysis shows that the proposed model is scale-free at different probability values and its clustering coefficients are adjustable, and the Barabasi-Albert model is a special case of p = 0 in our model. In addition, the analytical results of the clustering coefficients can be estimated using mean-field theory. The mean clustering coefficients calculated from the simulated data and the analytical results tend to be stable. The model also exhibits small-world characteristics and has good reproducibility for short distances of real networks. Our model combines three network characteristics, scale-free, high clustering coefficients, and small-world characteristics, which is a significant improvement over traditional models with only a single or two characteristics. The theoretical analysis procedure can be used as a theoretical reference for various network models to study the estimation of clustering coefficients. The existence of stable equilibrium points of the model explains the controversy of whether scale-free is universal or not, and this explanation provides a new way of thinking to understand the problem.
网络在现实生活中普遍存在,网络演化模型的研究对于理解现实网络的性质和规律非常重要。在现有的经典模型中,节点初始度的分布是常数或均匀的。该模型呈现二项分布,与实际网络数据一致。理论分析表明,该模型在不同概率值下是无标度的,聚类系数是可调的,Barabasi-Albert模型是模型中p = 0的特例。此外,利用平均场理论可以估计聚类系数的分析结果。由模拟数据计算的平均聚类系数与分析结果趋于稳定。该模型还具有小世界特性,对实际网络的短距离具有良好的再现性。我们的模型结合了三种网络特征,即无标度、高聚类系数和小世界特征,与传统的只有一个或两个特征的模型相比,这是一个显著的改进。理论分析过程可作为各种网络模型研究聚类系数估计的理论参考。模型稳定平衡点的存在解释了无标度是否普遍存在的争议,这一解释为理解问题提供了一种新的思路。
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引用次数: 0
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J. Appl. Math.
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