Dynamics Analysis and Optimality in Selective Harvesting Predator-Prey Model With Modified Leslie-Gower and Holling-Type II

In this work, we consider the optimal harvesting and stability problems of a prey-predator model with modified Leslie-Gower and Holling-type II functional response. The model is governed by a system of three differential equations which describe the interactions between prey, predator and harvesting effort. Boundedness and existence of solutions for this system are showed. The existence and local stability of the possible steady states are analyzed and the conditions of global stability of the interior equilibrium are established by using the Lyapunov function, we prove also the occurrence of Hopf bifurcation at this point. By using the Pontryagin’s maximal principle, we formulate and we solve the problem of the optimal harvest policy. In the end, some numerical simulations are given to support our theoretical results.

Optimization in an asymmetric Lanchester (n, 1) model

Counter-terrorism is a global task that every nation is concerned about. To improve operations against terrorism, many nations carry out counter-terroristic operations not only by themselves but also in cooperation with other nations. In this paper, we propose an extended the Kaplan-Kress-Szechtman model to cope with multi-party counter-terrorism. The optimal control problem for this model is studied. Our main tool is Pontryagin’s maximal principle. The optimal intelligence level and individual reinforcement of each party are found. The numerical results show that counter-terrorism operations in cooperative models are more effective than that in single models.

Analysis of a Fishery Model with two competing prey species in the presence of a predator species for Optimal Harvesting

A harvesting fishery model is proposed to analyze the effects of the presence of red devil fish population, as a predator in an ecosystem. In this paper, we consider an ecological model of three species by taking into account two competing species and presence of a predator (red devil), the third species, which incorporates the harvesting efforts of each fish species. The stability of the dynamical system is discussed and the existence of biological and bionomic equilibrium is examined. The optimal harvest policy is studied and the solution is derived in the equilibrium case applying Pontryagin’s maximal principle. The simulation results is presented to simulate the dynamical behavior of the model and show that the optimal equilibrium solution is globally asymptotically stable. The results show that the optimal harvesting effort is obtained regarding to bionomic and biological equilibrium.

Analysis of a Prey-Predator Fishing Model for Harvesting with The Limited Effect of Density and Toxicity

We proposed a model of prey-predator fishing by considering proportion of prey density and toxicity in ecosystem. The model is analysed to study about biological equilibrium, bionomic equilibrium and its stability. The aim of the model is to determine the optimal sustainable harvesting for each species. The optimal harvesting is resulted from Pontryagin’s maximal principle. The global stability of coexistence equilibrium is analyzed from Lyapunov function. The effect of toxicity leads to the decreasing of sustainable harvesting.

On the simultaneous recovery of boundary heat transfer coefficient and initial heat status

Consider the heat conduction process with heat flux exchanges on the boundary of a 2-dimensional domain. The aim is to identify both the boundary heat exchange coefficient and the initial heat distribution simultaneously from the final measurement data of the heat field. We prove the uniqueness for this nonlinear inverse problem for the strictly positive exchange coefficient and initial heat distribution in terms of the maximal principle and the eigenfunction expansions. Then a regularizing scheme combining the data mollification and quasi-reversibility method along time direction together is established to recover two unknowns, with the choice strategies for the regularizing parameters and the error estimates on the regularizing solutions. The reconstruction implementations are carried out in terms of the potential representation of the heat field, with numerical examples showing the validity of the proposed scheme.

New Results for Multipoint Singular Boundary Value Problems on a Measure Chain

We study the existence and uniqueness of positive solutions for a class of singularm-point boundary value problems of second order differential equations on a measure chain. A sharper sufficient condition for the existence and uniqueness ofCrd⁡1[0,T]positive solutions as well asCrd⁡1[0,T]positive solutions is obtained by the technique of lower and upper solutions and the maximal principle theorem.

Mean Curvature Type Flow with Perpendicular Neumann Boundary Condition inside a Convex Cone

We investigate the evolution of hypersurfaces with perpendicular Neumann boundary condition under mean curvature type flow, where the boundary manifold is a convex cone. We find that the volume enclosed by the cone and the evolving hypersurface is invariant. By maximal principle, we prove that the solutions of this flow exist for all time and converge to some part of a sphere exponentially asttends to infinity.