scholarly journals Mathematical Modeling of the Pandemic Peak

2022 ◽  
Vol 10 (E) ◽  
pp. 22-26
Author(s):  
Nadezhda Cherkunova

BACKGROUND:  The article examines the history and statistics of the pandemic spread. AIM: The study aimed to  develop a mathematical model reflecting the time dependence of the parameters characterizing the spread of the pandemic. MATERIALS AND METHODS: Differential equations were used to study the spread of the pandemic. RESULTS:  The case, where the coefficients of morbidity and recovery are different is considered. The patterns of change in the number of people susceptible to the disease and the number of infectious patients are revealed as a function of time. Using the developed model, the peak of the pandemic is found, i.e., the time at which the number of infectious patients will be the maximum.

2020 ◽  
Vol 13 (08) ◽  
pp. 2050167
Author(s):  
Anka Markovska

A mathematical model of adaptive immune response after transplantation is formulated by five nonlinear ordinary differential equations. Theorems of existence, uniqueness and nonnegativity of solution are proven. Numerical simulations of immune response after transplantation without suppression of acquired cellular immunity and after suppression were performed.


2016 ◽  
Vol 7 (3) ◽  
pp. 1271
Author(s):  
Jorge Guerra Pires

The ambition of this document is to set in evidence the prerequisite for integrative (mathematical) models, mechanism-based models, for appetite/bodyweight control. For achieving this goal, it is provided a scrutinized literature review and it is organized them in such a way to make the point. The quantitative methods exploited by the authors are called differential equations solved numerically; they are discussed briefly since it is not our goal herein to handle details. On the current state of the art, there is no mathematical model to the best of the author’s knowledge targeting at integrating several hormones at once in mathematical descriptions: even for single hormones, the literature is either occasional or do not exist at all; it is depicted some results for simple models already built. As it can be seen, the functions and roles seem fuzzy, most hormones seem to be piloting the same undertaking. The key challenge from a mathematical modeling perspective is how to separate properly the mechanisms of each hormone. The kind of pursuit presented herein could initiate an imperative cascade of mathematical modeling applied to metabolism of bodyweight control and energy homeostasis.


Author(s):  
И.А. Шаповалова

Современная иммунология не может успешно развиваться без помощи математического моделирования. Математические модели являются эффективным фильтром идей и индикатором правильности выбранных предположений, позволяют дать правильную интерпретацию результатам и выбирать критерии для оценки правильности, могут быть использованы как средство для визуализации результатов вычисления, что помогает дальнейшему развитию вычислительных алгоритмов. Исследование математической модели иммунной системы позволяет сравнивать теоретические и экспериментальные результаты и уточнять предположения, положенные в основу математического моделирования. Иммунная система является высокоразвитой биологической системой, функция которой заключается в выявлении и уничтожении чужеродного агента, поэтому она должна распознавать разнообразных возбудителей. Иммунная система способна к обучению, запоминанию, распознаванию образов, аналогичными свойствами обладают искусственные нейронные сети. Искусственные нейронные сети, подобно биологическим, являются вычислительной системой с огромным числом параллельно функционирующих простых процессоров с огромным числом связей. Нейросетевые алгоритмы используются в кластеризации, визуализации данных, контроле и оптимизации управляемых процессов, разработке искусственных нейронных сетей. В работе исследуется математическая модель иммунной системы, которая моделируется с помощью искусственной нейронной сети и описывается системой дифференциальных уравнений с запаздыванием. При анализе модели используется аппарат математической теории оптимального управления, а именно принцип максимума для систем дифференциальных уравнений с запаздыванием в аргументе функции состояния и аппарат методов оптимизации, базирующийся на методе быстрого автоматического дифференцирования. Вместо традиционных методов программирования используется обучение полносвязной искусственной нейронной сети с помощью метода распространения ошибки. Modern immunology can not be developed successfully without the help of mathematical modeling. Mathematical models are an effective way filter and indicator of the correctness of the selected assumptions. Mathematical models allow us to give a correct interpretation of the results, to select criteria for evaluating the correctness and that help the development of the numerical methods and algorithm. The research of the mathematical model of the immune system allow to compare theoretical and experimental results and clarified mathematical assumptions laid down in the basis of mathematical modeling. The immune system is a highly developed biological system, whose function is to detect and destroy foreign substance, so it needs to recognize a variety of pathogens.The immune system is capable of learning to remember the recognitions of images. The similar properties possess artificial neural networks. Similar to biological ones artificial neural networks are computer systems with a huge number of parallel functioning simple processors and with a large number of connections. Neural networks algorithms are used in clustering, data visualization, control and optimization of processes, the development of artificial neural networks. In the article we consider mathematical model of immune system modeled with the help of artificial multi layer neural net described by the system of differential equations with delay in argument of state functions. The model is analyzed with the help of the theory of optimal control namely the maximum principle of Pontrjagin for the systems of differential equations with delay in argument of the state functions. The method of optimization is based on the method of fast automatic differentiations. Instead of traditional methods of programming the training of the fully connected neural networks and the error propagation method are used.


Author(s):  
M. S Seheda ◽  
Ye. V Cheremnykh ◽  
P. F Gogolyuk ◽  
Yu. V Blyznak

Purpose. To create a method for mathematical modeling of wave processes in power two-winding transformers based on a substitute scheme, which takes into account the design features of power transformers. Methodology. Formation of mathematical models for the research on wave processes in power two-winding transformers and further development of the analytical method for solving the system of partial differential equations. Findings. A mathematical model for the research on wave processes in power two-winding transformers based on a substitution scheme, witch adequately takes into account both electrical and magnetic connections, is created and an improved analytical method is proposed for solving a system of partial differential equations which allows taking into account the interval time of propagation of electromagnetic waves along the entire length of the windings and the time interval, during which the voltage changes significantly from its complete change during the wave processes,. Originality. The paper proposes a mathematical model for the research on wave processes in the windings of power two-winding transformers based on its alternative scheme, which takes into account electrical and magnetic connections, and improves the Fourier method for solving a system of differential equations with partial derivatives. Practical value. A mathematical model is created for calculating wave processes in transformers, which allows analyzing the voltage distribution in the transformer windings during the action of pulse voltage on them and adjusting their insulating abilities, given that the operation of power transformers is subject to high requirements for the reliability of their work.


2007 ◽  
Vol 12 (4) ◽  
pp. 511-524 ◽  
Author(s):  
A. K. Misra

In this paper a non-linear mathematical model is proposed for a qualitative representation of ecosystem dynamics in a eutrophied water body. The model variables are the concentration of nutrients, densities of algal population, zooplankton population, detritus and the concentration of dissolved oxygen. The model consists of five coupled ordinary differential equations. By using the qualitative theory of differential equations the model steady-state dynamics are studied. Simulation analysis is also performed to see the effect of rate of input of nutrients on different variables participating in the proposed model.


2018 ◽  
Vol 22 ◽  
pp. 01029
Author(s):  
Özlem ERTEKİN

Mathematical modeling of biochemical, chemical reaction processes facilitates understanding. The kinetics of these reaction processes can be analyzed mathematically and kinetics are presented as systems of differential equations. Mathematical model of a reaction kinetic is studied in this study. Bernoulli-Sub equation function method is used in this study. This example can be new model for food engineering applications.


1998 ◽  
Vol 2 ◽  
pp. 23-30
Author(s):  
Igor Basov ◽  
Donatas Švitra

Here a system of two non-linear difference-differential equations, which is mathematical model of self-regulation of the sugar level in blood, is investigated. The analysis carried out by qualitative and numerical methods allows us to conclude that the mathematical model explains the functioning of the physiological system "insulin-blood sugar" in both normal and pathological cases, i.e. diabetes mellitus and hyperinsulinism.


Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.


2017 ◽  
Vol 992 (4) ◽  
pp. 32-38 ◽  
Author(s):  
E.G. Voronin

The article opens a cycle of three consecutive publications dedicated to the phenomenon of the displacement of the same points in overlapping scans obtained adjacent CCD matrices with opto-electronic imagery. This phenomenon was noticed by other authors, but the proposed explanation for the origin of displacements and the resulting estimates are insufficient, and developed their solutions seem controversial from the point of view of recovery of the measuring accuracy of opticalelectronic space images, determined by the physical laws of their formation. In the first article the mathematical modeling of the expected displacements based on the design features of a scanning opto-electronic imaging equipment. It is shown that actual bias cannot be forecast, because they include additional terms, which may be gross, systematic and random values. The proposed algorithm for computing the most probable values of the additional displacement and ways to address some of the systematic components of these displacements in a mathematical model of optical-electronic remote sensing.


Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1309
Author(s):  
P. R. Gordoa ◽  
A. Pickering

We consider the problem of the propagation of high-intensity acoustic waves in a bubble layer consisting of spherical bubbles of identical size with a uniform distribution. The mathematical model is a coupled system of partial differential equations for the acoustic pressure and the instantaneous radius of the bubbles consisting of the wave equation coupled with the Rayleigh–Plesset equation. We perform an analytic analysis based on the study of Lie symmetries for this system of equations, concentrating our attention on the traveling wave case. We then consider mappings of the resulting reductions onto equations defining elliptic functions, and special cases thereof, for example, solvable in terms of hyperbolic functions. In this way, we construct exact solutions of the system of partial differential equations under consideration. We believe this to be the first analytic study of this particular mathematical model.


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