Identification And Simulation Of HBV Dynamic Model

Based on the summarization of the study of domestic and foreign HBV mathematical models researches and the parameters identification technology, in this thesis, the HBV dynamics model was improved on the basis of the interaction mechanism of the hepatitis B virus, liver cells and the immune system. And simulated the various clinical symptoms of hepatitis B to verify the effectiveness of the HBV dynamic model. Then based on the HBV dynamic models and the hepatitis B patients'clinical examination data, this thesis introduced the parameters identification technology to identify the parameters in HBV dynamic model which closely related to the illness development of the hepatitis B patients, such as the parameters related to the infection and replication capabilities of HBV and the parameters related to the cure and kill capabilities of the T cells. Thus the results of the parameters identification were used to simulate the illness development situation and the development trends of hepatitis B patients, including the development of patients'healthy liver cells, infected liver cells, the total amount of liver cells, the HBV DNA content, the CTL content and the ALT content, to provide a new method and a assistant measure for the hepatitis B patients'diagnosis and the curative effect assessment.After the study of the research on parameters identification and the application in engineering, this thesis used two different parameters identification methods to identify the HBV dynamic models, respectively are the multi-directional search method and the BP neural network method. Through the comparison results of the two different parameters identification methods based on the hepatitis B patients'clinical examination data, this thesis discussed the characteristics, the advantages, the disadvantages and the adaptability of these two kinds of methods used in the HBV dynamics model. Then the conclusion about the characteristics and the reason of the existence of errors in the identification of HBV dynamic model was made.Finally, this thesis analyzed the defects and the possibly improving ways in the HBV dynamic model, and discussed the difficulty in the parameters identification of HBV dynamic model.