具有年龄结构的捕食种群系统的最优收获策略

分析了一类基于年龄结构的食饵-捕食者系统的最优收获问题．证明了系统非负解的存在唯一性、解对控制变量的连续依赖性．讨论了最优策略的存在性,利用法锥和Dubovitskii-Milyutin理论导出了最优性条件．     

Analysis and discretization of an optimal control problem for the time-periodic MHD equations

We consider the mathematical formulation and analysis of an optimal control problem associated with the tracking of the velocity and the magnetic field of a viscous, incompressible, electrically conducting fluid in a bounded two-dimensional domain through the adjustment of distributed controls. Existence of optimal solutions is proved and first-order necessary conditions for optimality are used to derive an optimality system of partial differential equations whose solutions provide optimal states and controls. Semidiscrete-in-time approximations are defined and their convergence to the exact optimal solutions is shown.     

OPTIMAL CONTROL FOR LINEAR SYSTEM WITH QUADRATIC INDEFINITE CRITERION ON HILBERT SPACES

In this paper we consider optimal control problems for linear system on real separableHilbert spaces with quadratic criterion,in which the state weighted operators are indefinite.Wellposedness and solvability,existence and uniqueness of optimal control are discussed.Weprove that the closed-loop syntheses of optimal control are state linear feedback.Existence ofsolutions of related operator Riccati equations is investigated.     

A FINITE ELEMENT COLLOCATION METHOD FOR TWO-PHASE INCOMPRESSIBLE IMMISCIBLE PROBLEMS

Two-phase,incompressible,immiscible flow in porous media is governed by a coupled system of nonlinear partial differential equations.The pressure equation is elliptic, whereas the concentration equation is parabolic,and both are treated by the collocation scheme.Existence and uniqueness of solutions of the algorithm are proved.A optimal convergence analysis is given for the method.     

A synthesis problem for the optimal control of epidemics *

The present paper deals with the problem of preventing an epidemic by vaccination. Existence and uniqueness results for the optimal solutions are obtained. Moreover it is shown that if the treatment interval is suitably small then the problem has a unique optimal synthesis.     

The optimization of directivity and signal-to-noise ratio of an arbitrary antenna array

The authors consider the optimization of the signal-to-noise ratio of an arbitrary cylindrical antenna array. Existence of an optimal solution and convergence of finite-dimensional approximations is shown. The necessary optimality conditions are used to compute optimal solutions for some numerical examples.     

Global solutions for a class of hamilton-jacobi equations in hilbert spaces

Existence and uniqueness results for Hamilton-Jacobi equations in Hilbert spaces are given. These solutions allow to find optimal feedback controls for the linear quadratic regulator problem with constrained controls.     

Tracking nonperiodic trajectories with the overtaking criterion

A tracking problem on an infinite time interval is studied, where the plant is linear with quadratic cost, and the tracked trajectory is not necessarily period. Optimal solutions with respect to the overtaking criterion are studied. Existence and uniqueness of such optimal solutions are proved and they are shown to be given by a linear feedback law which is the same as in the periodic case. A close relation between the solutions of tracking problems where the tracked trajectories are different only for very large times is established.     

OPTIMAL HARVESTING OF A SPATIALLY EXPLICIT FISHERY MODEL

Abstract We consider an optimal fishery harvesting problem using a spatially explicit model with a semilinear elliptic PDE, Dirichlet boundary conditions, and logistic population growth. We consider two objective functionals: maximizing the yield and minimizing the cost or the variation in the fishing effort (control). Existence, necessary conditions, and uniqueness for the optimal harvesting control for both cases are established. Results for maximizing the yield with Neumann (no‐flux) boundary conditions are also given. The optimal control when minimizing the variation is characterized by a variational inequality instead of the usual algebraic characterization, which involves the solutions of an optimality system of nonlinear elliptic partial differential equations. Numerical examples are given to illustrate the results.     

A class of nonlinear integrodifferential impulsive periodic systems of mixed type and optimal controls on Banach space

A class of nonlinear integrodifferential impulsive periodic systems of mixed type on Banach space is considered. Existence of periodic PC-mild solutions is proved. Existence of periodic optimal pairs of systems governed by nonlinear impulsive integrodifferential equations of mixed type is also presented. An example is given for demonstration.     

Optimal Control of Obstacle Problems by H1-Obstacles

Optimal control of variational inequalities with the controls given by the obstacles is considered. Existence optimal solutions are proved for obstacles with H¹ regularity and first-order optimality conditions are derived which, under additional assumptions, are also sufficient. A numerical algorithm is proposed and its practical feasibility is investigated.     

State-constrained optimal control of the three-dimensional stationary Navier-Stokes equations

In this paper, an optimal control problem for the stationary Navier-Stokes equations in the presence of state constraints is investigated. Existence of optimal solutions is proved and first order necessary conditions are derived. The regularity of the adjoint state and the state constraint multiplier is also studied. Lipschitz stability of the optimal control, state and adjoint variables with respect to perturbations is proved and a second order sufficient optimality condition for the case of pointwise state constraints is stated.     

Optimal control problem on insect pest populations

In this article we present a model of insect infestation of grape vines and consider the optimal control of the pest through egg population removal. Existence and uniqueness of solutions are proved.     

Mixed Finite Element Methods for the Ferrofluid Model with Magnetization Paralleled to the Magnetic Field

Mixed finite element methods are considered for a ferrofluid flow model with magnetization paralleled to the magnetic field. The ferrofluid model is a coupled system of the Maxwell equations and the incompressible Navier-Stokes equations. By skillfully introducing some new variables, the model is rewritten as several decoupled subsystems that can be solved independently. Mixed finite element formulations are given to discretize the decoupled systems with proper finite element spaces. Existence and uniqueness of the mixed finite element solutions are shown, and optimal order error estimates are obtained under some reasonable assumptions. Numerical experiments confirm the theoretical results.     

A class of fractional delay nonlinear integrodifferential controlled systems in Banach spaces

We study a class of fractional delay nonlinear integrodifferential controlled systems associated with analytic semigroup in Banach spaces. Existence of α-mild solutions and optimal controls are obtained. Lastly, an example is presented to illustrate our abstract results.     

Semidiscrete approximations of optimal Robin boundary control problems constrained by semilinear parabolic PDE

An optimal Robin boundary control problem associated with semilinear parabolic partial differential equations is considered. Existence of an optimal solution is proved and an optimality system of equations is derived. Semidiscrete finite element approximations of the optimality system are defined and error estimates are obtained.     

Fast Solvers of Fredholm Optimal Control Problems

<正>The formulation of optimal control problems governed by Fredholm integral equations of second kind and an efficient computational framework for solving these control problems is presented.Existence and uniqueness of optimal solutions is proved. A collective Gauss-Seidel scheme and a multigrid scheme are discussed.Optimal computational performance of these iterative schemes is proved by local Fourier analysis and demonstrated by results of numerical experiments.     

Optimal control problems in diffusion processes with a nonsmooth nonlinear boundary condition

We investigate a one-dimensional diffusion process controlled by a nonsmooth nonlinear boundary condition. Existence and estimates of positive solutions of the differential equation are derived. We prove necessary conditions for optimal controls and apply them to two examples.     

Sequential Quadratic Programming Method for Volatility Estimation in Option Pricing

Our goal is to identify the volatility function in Dupire’s equation from given option prices. Following an optimal control approach in a Lagrangian framework, a globalized sequential quadratic programming (SQP) algorithm combined with a primal-dual active set strategy is proposed. Existence of local optimal solutions and of Lagrange multipliers is shown. Furthermore, a sufficient second-order optimality condition is proved. Finally, some numerical results are presented underlining the good properties of the numerical scheme.     

An optimal order convergence for a weak formulation of the compressible Stokes system with inflow boundary condition

Summary. We formulate the compressible Stokes system given in (1.1) into a (new) weak formulation (2.1). A finite element method for this is presented. Existence and uniqueness of the finite element method is shown. An optimal error estimate for the numerical approximation is obtained. Numerical examples are given, showing its efficiency and rates of convergence of the approximate solutions that results from the discrete problem (3.1). Received October 20, 1996 / Revised version received January 21, 1999 / Published online: April 20, 2000