查看更多>>摘要：For an unstable Markov jump stochastic differential system (MJ-SDS) with high nonlinearity, can one introduce a discrete feedback control to stabilize it? This question has been well answered for the case of the feedback control derived from discrete state observations, in the form of H-infinity stabilization and exponential stabilization. Whereas, the existing theory can not tackle the non-autonomous systems and do not consider the factor of discrete mode observations, which are the motivations of this paper. Fortunately, for an unstable non-autonomous MJ-SDS, the feedback control, originated from discrete observations of system state and system mode, is well designed to stabilize it not only in the sense of exponential decay rate but also of polynomial decay rate and even general decay rate. Thereinto, the designing rule of discrete feedback control is given as well. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Following to the thermal applications of optimized nanoparticles, the inspired attention is devoted by scientists on this topic as it attribute dynamic role in the engineering and different industrial processes. The phenomenon of entropy generation is quite significant for the ensuring the enhanced thermal features and stability of nanoparticles. This thermal contribution addressed the optimized aspects of viscous nanoparticles confined by curved surface with Joule heating and viscous dissipation thermal reflections. Moreover, the radiative pattern is also observed to execute the energy enhancement. The slip enrollment is considered instead of traditional no-slip flow mechanism. After re-attaining dimensionless form of governing equations, the shooting algorithm via MATLAB software is developed. The confirmations of obtained numerical data are verified after comparative analysis. The physical sense of parameters is observed with graphical framework. The change in entropy generation and Bejan number is also visualized in view of parameters. Based on reported outcomes, it is concluded that curvature parameter improves the change in velocity while velocity profile reduces with implementation of slip factors. The radiation parameter and curvature constant enhanced the temperature. Moreover, the enhancement in slip parameters increases the Bejan number. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：A kinetic model, describing the influence of decision-making competence in evolution of wealth for a multi-agent system with feedback control, is investigated. The control term is analyzed by the minimization of a quadratic cost functional, which aims to decrease the wealth gap between agents. The constant saving propensities and diffusion coefficients in the model are modified as functions of wealth and decision competence, respectively. In our micro binary wealth exchange model, an extra risk shared by all agent is discussed, which increases the inequality of wealth distribution. The main macro properties of the kinetic model and the marginal distributions of wealth and decision-making competence are considered through several examples. Our results illustrate that the disequilibrium of decision-making competence is one of the reasons to increase wealth inequality. (C) 2021 Published by Elsevier Inc.
Ismaeel, A. M.Mansour, M. A.Ibrahim, F. S.Hady, F. M....
12页
查看更多>>摘要：Heat transfer in the biological tissue during/after thermal therapy is dominated by the blood perfusion in the tissue. In this study we introduce a mathematical model to simulate the heat and nanoparticle transport in the tissue in the presence of a vertical vessel at the microscale. This model incorporates the effects of the nanoparticle Brownian motion, nanoparticle transport due to thermophoresis and heat transfer by radiation. We consider the nanoparticles and the interstitial fluid extravasate from the vessel into the surrounding tissue through a uniform distribution of pores at the vessel wall. We introduce similarity transformations to convert the governing equations into a system of ODEs, which we solve numerically using MATLAB. The model predictions show a significant influence of the vessel pore size on the heat transfer in the tissue. On the other hand, the nanoparticle transport across the tissue depends on the thermophoresis parameter. Furthermore, the heat removal from the tissue by the vessel strongly depends on the fluid extravasation velocity and the heat flux across the tissue outer boundary interface. (C) 2021 Elsevier Inc. All rights reserved.
Henning, Michael A.Pilsniak, MonikaTumidajewicz, Elzbieta
11页
查看更多>>摘要：A set Sof vertices in a graph G is a paired dominating set if every vertex of G is adjacent to a vertex in Sand the subgraph induced by Scontains a perfect matching (not necessarily as an induced subgraph). The minimum cardinality of a paired dominating set of G is the paired domination number gamma(pr)(G) of G. In this paper, we show that if G is a graph of order n and delta(G) >= 3, then gamma(pr)(G) <= 19037/30000 n < 0.634567 n. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The single server queueing system is investigated. When the system is idle or while serving a customer, it fails at random. System failure is classified into two types: hard failure and soft failure. Hard failure usually necessitates the repairman's physical presence and takes a long time. Soft failure, on the other hand, takes less time because the system can be restored to operation by simply rebooting it. When the system is being repaired, the server is forced to take a vacation and the repair process begins immediately. The model's transient state probabilities are derived and using the final value theorem of the Laplace transform, steady state probabilities are derived from transient state probabilities. Finally, numerical illustrations are provided to demonstrate the system's behaviour as the parameters' values are varied. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：In this paper, we develop a hybrid spectral method for the nonlinear second-kind Volterra integral equations (VIEs) with weakly singular kernel and vanishing delays. Our main strategy is to divide the original interval into subintervals, to employ the shifted generalized log orthogonal functions (GLOFs) as the basis on the first interval, to take the classical shifted Legendre polynomials as the basis on other intervals. We analyze the existence and uniqueness of the numerical scheme, and derive the corresponding error estimates. A series of examples demonstrate the effectiveness of the proposed method. (C) 2021 Elsevier Inc. All rights reserved.
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