| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
・ We have studied the Lotka-Volterra two species system with competitive relationship which is disappeared periodically in time. In the period without competitive relationship, each of two species populations grows independently of each other. Our results show that such temporally intermittency of competitive relationship can cause the change of which species goes extince or the coexistence of two species. Results about the relation between such specific phases and the parameters in model have been presented in part at some domestic or international scientific meetings, and are planned to be published in paper in 2002.
・ We have studied some mathematical methods to analyze the Lotka-Volterra prey-predator system with temporally intermittent disturbance. Method developed by P.H. Leslie (1958) in some intuitive way is extended and applied for Lotka-Volterra prey-predator ODE system, and we can obatin a time-discrete dynamical system derived from it, which conserves the characteristics of original ODE dynamical system. We applied our extended method for the other fundamental mathematical models in Mathematical Biology, and show that those derived time-discrete systems can conserve well the behavior of solution for the original system. Some results have been already presented in some domestic and international scientific meetings.
・ We have studied the Lotka-Volterra prey-predator system with harvestion term which is temporally intermittent, that is, which is disappeared periodically in time. In the system with temporally continuous harvestion, the extinction of prey or predator occurs in a finite time, depending on the initial condition. In contrast, as for the system with temporally intermittent harvestion, the conclusion of population dynamics can change : for instance, the extinct species is changed. Some results will be presented in some domestic and international scientific meetings.
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