Project Objectives: 1. Develop necessary theory, techniques and tools to construct and analyze models of nonlinear systems. 2. Construct appropriate models of nonlinear systems such as the hormone secretion system, mechanical ventilation, bacteria growth in the presence of antibiotics, blood flow, tumor growth, disease transmission, and other biological processes of current interest. 3. Analyze the models theoretically and numerically to gain insights leading to useful suggestions for control/management strategies. Research Activities: This research team has in fact been studying, as well as those originally proposed for this project, several other biological systems which were not specifically mentioned in the proposal, yielding a lot more international publications than what has been promised. The following is the detailed description of activities and outputs of each subproject in the past 3 years. Subproject 1: Dynamical Modeling of Systems in Medical Science Subproject 2: Mathematical Modeling of Blood Flow in the Coronary Artery Bypass Grafting Subproject 3: Mathematical Modeling of Disease Transmission Subproject 4: Application of Log-linear and Logistic Models to Cancer Patients: A Case Study of the National Cancer Institute Subproject 5: Modeling and Computer Simulation in Cancer Research: Theory and Modeling of the Growth of Tumors Subproject 6: Research on Asymptotic Stability of Difference Equations with Delays