Static stability analysis of the two-point mooring autonomous underwater vehicle(AUV) is presented.The mathematic model is a set of equilibrium equations describing the attitude of the AUV.The mooring lines are regard...Static stability analysis of the two-point mooring autonomous underwater vehicle(AUV) is presented.The mathematic model is a set of equilibrium equations describing the attitude of the AUV.The mooring lines are regarded as inelastic catenaries,and five degrees of freedom of AUV are considered.The stability of the system is represented by inequality conditions between several physical quantities and the corresponding limitations.We analyze stability of the prime AUV and find that the AUV has a flow-following tendency,which makes the swing angle big.The result shows that the two-point mooring AUV can remain stable under 2.5 kn ocean current speed,and it will weigh anchor when the speed is greater than 3 kn.Subsequent parametric study reveals the influence of the designing parameters on the stability.展开更多
Bubonic plague is a serious bacterial disease, mainly transmitted to human beings and rodents through flea bite. However, the disease may also be transmitted upon the interaction with the infected materials or surface...Bubonic plague is a serious bacterial disease, mainly transmitted to human beings and rodents through flea bite. However, the disease may also be transmitted upon the interaction with the infected materials or surfaces in the environment. In this study, a deterministic model for bubonic plague disease with Yersinia pestis in the environment is developed and analyzed. Conditions for existence and stability of the equilibrium points are established. Using Jacobian method disease free equilibrium (DFE) point, E<sup>0</sup> was proved to be locally asymptotically stable. The Metzler matrix method was used to prove that the DFE was globally asymptotically stable when R<sub>0</sub> < 1. By applying Lyapunov stability theory and La Salles invariant principle, we prove that the endemic equilibrium point of system is globally asymptotically stable when R<sub>0</sub> > 1. Numerical simulations are done to verify the analytical predictions. The results show that bubonic plague can effectively be controlled or even be eradicated if efforts are made to ensure that there are effective and timely control strategies.展开更多
基金the National Natural Science Foundation of China(No.11302176)the Special Research Fund for the Doctoral Program of Higher Education of China(No.20126102120021)
文摘Static stability analysis of the two-point mooring autonomous underwater vehicle(AUV) is presented.The mathematic model is a set of equilibrium equations describing the attitude of the AUV.The mooring lines are regarded as inelastic catenaries,and five degrees of freedom of AUV are considered.The stability of the system is represented by inequality conditions between several physical quantities and the corresponding limitations.We analyze stability of the prime AUV and find that the AUV has a flow-following tendency,which makes the swing angle big.The result shows that the two-point mooring AUV can remain stable under 2.5 kn ocean current speed,and it will weigh anchor when the speed is greater than 3 kn.Subsequent parametric study reveals the influence of the designing parameters on the stability.
文摘Bubonic plague is a serious bacterial disease, mainly transmitted to human beings and rodents through flea bite. However, the disease may also be transmitted upon the interaction with the infected materials or surfaces in the environment. In this study, a deterministic model for bubonic plague disease with Yersinia pestis in the environment is developed and analyzed. Conditions for existence and stability of the equilibrium points are established. Using Jacobian method disease free equilibrium (DFE) point, E<sup>0</sup> was proved to be locally asymptotically stable. The Metzler matrix method was used to prove that the DFE was globally asymptotically stable when R<sub>0</sub> < 1. By applying Lyapunov stability theory and La Salles invariant principle, we prove that the endemic equilibrium point of system is globally asymptotically stable when R<sub>0</sub> > 1. Numerical simulations are done to verify the analytical predictions. The results show that bubonic plague can effectively be controlled or even be eradicated if efforts are made to ensure that there are effective and timely control strategies.
