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Global dynamics of a differential susceptibility model
, Article International Journal of Biomathematics ; Volume 5, Issue 5 , September , 2012 ; 17935245 (ISSN) ; Yasaman, S ; Sharif University of Technology
2012
Abstract
An SIS epidemiological model in a population of varying size with two dissimilar groups of susceptible individuals has been analyzed. We prove that all the solutions tend to the equilibria of the system. Then we use the Poincaré Index theorem to determine the number of the rest points and their stability properties. It has been shown that bistability occurs for suitable values of the involved parameters. We use the perturbations of the pitchfork bifurcation points to give examples of all possible dynamics of the system. Some numerical examples of bistability and hysteresis behavior of the system has been also provided
Global analysis of a model of differential susceptibility induced by genetics
, Article Nonlinear Analysis: Real World Applications ; Volume 12, Issue 4 , 2011 , Pages 2183-2197 ; 14681218 (ISSN) ; Yasaman, S ; Sharif University of Technology
2011
Abstract
This paper is concerned with global analysis of an SIS epidemiological model in a population of varying size with two dissimilar groups of susceptible individuals. We prove that this system has no periodic solutions and use the Poincar index theorem to determine the number of rest points and their stability properties. It has been shown that multiple equilibria (bistability) occurs for suitable values of parameters. We also give some numerical examples of all possible bifurcations of this system
Heart Arrhythmia Classification based on Nonlinear Analysis and Dynamic Behavior of Heart Rate Variability (HRV)Signal
, M.Sc. Thesis Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor) ; Ghorshi, Mohammad Ali (Co-Advisor)
Abstract
Detection and classification of arrhythmia is important especially for patients in Emergency care units. Early diagnosis of cardiac arrhythmia makes it possible to choose appropriate anti arrhythmic drugs, and is thus very important for improving arrhythmia therapy. Computer-Assisted Diagnostic (CAD) Systems are used in recent decades in which extracted features and classifiers are the most important factor. In this project, we try to focus on both of these two major factors in heart arrhythmia classification using HRV signal. Therefore, in this project, we try to classify different groups of arrhythmia using HRV signal processing especially the nonlinear processing. Our main aim is to...
Global analysis of an SAIS model
, Article Journal of Biological Dynamics ; Volume 6, Issue 2 , 2012 , Pages 457-474 ; 17513758 (ISSN) ; Yasaman, S ; Sharif University of Technology
2012
Abstract
This paper is concerned with global analysis of an SAIS epidemiological model in a population of varying size introduced by Busenberg and van den Driessche. In this model the population is divided into three subgroups of susceptible, asymptomatic and infective individuals. It has been shown that this system has no periodic solutions and all its trajectories tend to the equilibria of the system. We use the Poincaré Index theorem to determine the number of the equilibria and their stability properties. We have shown that bistability occurs for suitable values of parameters and found a set of examples of all possible dynamics of the system