This paper is devoted to the existence of the traveling waves of the equations describing a diffusive susceptible-exposed-infected-recovered(SEIR) model. The existence of traveling waves depends on the basic reproduct...This paper is devoted to the existence of the traveling waves of the equations describing a diffusive susceptible-exposed-infected-recovered(SEIR) model. The existence of traveling waves depends on the basic reproduction rate and the minimal wave speed. We obtain a more precise estimation of the minimal wave speed of the epidemic model, which is of great practical value in the control of serious epidemics. The approach in this paper is to use the Schauder fixed point theorem and the Laplace transform. We also give some numerical results on the minimal wave speed.展开更多
Two different methods to model a point absorber wave energy converter （WEC） with direct drive linear power take-off （PTO） are proposed in the present study： the frequency domain （FD） method and the time domain ...Two different methods to model a point absorber wave energy converter （WEC） with direct drive linear power take-off （PTO） are proposed in the present study： the frequency domain （FD） method and the time domain （TD） method. In the FD analysis, the frequency response function （FRF） of the WEC device is obtained via the equation of motion, and the expressions of power capture width in regular and random waves are derived as well. In the TD modeling, based on a state space approximation of the convolution term in the motion equation, both regular wave and random wave simulations are carded out. The regular wave simulation results indicate that the state space approximation is sufficiently accurate and the capture width reaches the maximum in the vicinity of the natural frequency. In the random wave simulations, the effects of buoy size, the PTO damping and wave climate on the power capture width are discussed in detail, which leads to the conclusion that the capture widths are influenced by the natural frequency of the WEC device, peak frequency of the wave spectrum, the amplitude of FRF and PTO damping. Furthermore, the increase of the capture width is at the cost of a relatively large buoy size and PTO damping when control is not included.展开更多
基金supported by National Natural Science Foundation of China(Grant No.11371058)the Fundamental Research Funds for the Central Universities
文摘This paper is devoted to the existence of the traveling waves of the equations describing a diffusive susceptible-exposed-infected-recovered(SEIR) model. The existence of traveling waves depends on the basic reproduction rate and the minimal wave speed. We obtain a more precise estimation of the minimal wave speed of the epidemic model, which is of great practical value in the control of serious epidemics. The approach in this paper is to use the Schauder fixed point theorem and the Laplace transform. We also give some numerical results on the minimal wave speed.
基金supported by the State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University(Grant No.GKZD010023)
文摘Two different methods to model a point absorber wave energy converter （WEC） with direct drive linear power take-off （PTO） are proposed in the present study： the frequency domain （FD） method and the time domain （TD） method. In the FD analysis, the frequency response function （FRF） of the WEC device is obtained via the equation of motion, and the expressions of power capture width in regular and random waves are derived as well. In the TD modeling, based on a state space approximation of the convolution term in the motion equation, both regular wave and random wave simulations are carded out. The regular wave simulation results indicate that the state space approximation is sufficiently accurate and the capture width reaches the maximum in the vicinity of the natural frequency. In the random wave simulations, the effects of buoy size, the PTO damping and wave climate on the power capture width are discussed in detail, which leads to the conclusion that the capture widths are influenced by the natural frequency of the WEC device, peak frequency of the wave spectrum, the amplitude of FRF and PTO damping. Furthermore, the increase of the capture width is at the cost of a relatively large buoy size and PTO damping when control is not included.
