Lijuan Wang’s research while affiliated with Wuhan University and other places

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Publications (29)


Numerical computation of t∗(M)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$t^*(M)$$\end{document}
Optimal controls of Examples 2 and 3. a Example 2, b Example 3
Optimal control of Example 4
Computation of Time Optimal Control Problems Governed by Linear Ordinary Differential Equations
  • Article
  • Publisher preview available

October 2017

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80 Reads

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16 Citations

Journal of Scientific Computing

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Lijuan Wang

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In this paper, a novel numerical algorithm is presented to compute the optimal time of a time optimal control problem where the governing system is a linear ordinary differential equation. By the equivalence between time optimal control problem and norm optimal control problem, computation of the optimal time can be obtained by solving a sequence of norm optimal control problems, which are transferred into their Lagrangian dual problems. The nonsmooth structure of the dual problem is approximated by the iteratively reweighted least square strategy. Several numerical tests are given to show the efficiency of the proposed algorithm.

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Bang-bang property of time optimal controls for some semilinear heat equation

October 2015

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51 Reads

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18 Citations

SIAM Journal on Control and Optimization

In this paper, we derive a bang-bang property of a kind of time optimal control problem for some semilinear heat equation on bounded C2C^2 domains (of the Euclidean space), with homogeneous Dirichlet boundary condition and controls distributed on an open and non-empty subset of the domain where the equation evolves.


Bang-bang property of time optimal controls of semilinear parabolic equation

June 2015

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44 Reads

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19 Citations

Discrete and Continuous Dynamical Systems

The bang-bang property of time optimal controls for a semilinear parabolic equation, with homogeneous Dirichlet boundary condition and distributed controls acting on an open subset of the domain is established. This relies on an observability estimate from a measurable set in time for a linear parabolic equation, with potential depending on both space and time variables. The proof of the bang-bang property relies on a Kakutani fixed point argument.


The bang-bang property of time optimal controls for the Burgers equation

September 2014

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60 Reads

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15 Citations

Discrete and Continuous Dynamical Systems

The bang-bang property of time optimal controls for the Burgers equations in dimension up to three, with homogeneous Dirichlet boundary conditions and distributed controls acting on an open subset of the domain is established. This relies on an observability estimate from a measurable set in time for linear parabolic equations, with potentials depending on both space and time variables. The proof of the bang-bang property relies on a Kakutani fixed point argument.


Bang-bang property for time optimal control of semilinear heat equation

May 2014

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96 Reads

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89 Citations

Annales de l Institut Henri Poincaré C Analyse Non Linéaire

This paper studies the bang-bang property for time optimal controls governed by semilinear heat equation in a bounded domain with control acting locally in a subset. Also, we present the null controllability cost for semilinear heat equation and an observability estimate from a positive measurable set in time for the linear heat equation with potential.


Time Optimal Controls of Semilinear Heat Equation with Switching Control

April 2014

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31 Reads

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18 Citations

Journal of Optimization Theory and Applications

This paper is concerned with the bang-bang property of time optimal controls, governed by a semilinear heat equation in a bounded domain with switching controls acting locally into two open subsets. The proofs rely on an observability estimate from a positive measurable set in time for the linear heat equation, and a Kakutani fixed point argument.


Time optimal control of the heat equation with pointwise control constraints

April 2013

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73 Reads

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60 Citations

ESAIM Control Optimisation and Calculus of Variations

Time optimal control problems for an internally controlled heat equation with pointwise control constraints are studied. By Pontryagin’s maximum principle and properties of nontrivial solutions of the heat equation, we derive a bang-bang property for time optimal control. Using the bang-bang property and establishing certain connections between time and norm optimal control problems for the heat equation, necessary and sufficient conditions for the optimal time and the optimal control are obtained.


Time optimal controls of the linear FitzHugh–Nagumo equation with pointwise control constraints

November 2012

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156 Reads

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48 Citations

Journal of Mathematical Analysis and Applications

Time optimal control governed by the internally controlled linear Fitzhugh-Nagumo equation with pointwise control constraint is considered. Making use of Ekeland's variational principle, we obtain Pontryagin's maximum principle for a time optimal control problem. Using the maximum principle, the bang-bang property of the optimal controls is established under appropriate assumptions.


Citations (20)


... The plan of the proof of Lemma 1, inspired by the ideas presented in [14,16,30], is outlined as follows. In Step 1, we perform a change of function and introduce both the symmetric and antisymmetric parts. ...

Reference:

Null Approximate Impulse Controllability for a Degenerate Parabolic Equation in Non Divergence Form with Drift
Quantitative unique continuation for parabolic equations with Neumann boundary conditions
  • Citing Article
  • January 2022

Mathematical Control and Related Fields

... There are many interesting works about norm optimal control problems governed by evolution equations (see, for instance, [10], [9], [7], [15], [14], [6], [16]). Most of them are mainly concerned with two topics: characterization of norm optimal controls, and connections between minimal (or maximal) time controls and the minimal norm controls. ...

Equivalence of three kinds of optimal control problems for linear heat equations with memory

ESAIM Control Optimisation and Calculus of Variations

... On the one side, we want to avoid chaos in some fields of engineering for its characteristic. On the other side, chaotic property can be applied in secure communication in order to enhance the security of information [1][2][3][4][5]. These extensive and deep researches lead to a large number of areas of implementation related to nonlinear systems with chaotic characteristic. ...

Exact synchronization and asymptotic synchronization for linear ODEs
  • Citing Article
  • December 2021

Science China Mathematics

... In [20], the authors proved that the unique continuation estimate for the pure heat equation in R n holds if and only if the unbounded observable set is thick set. In [21,22], the authors proved a global interpolation inequality for solutions of the heat equation with bounded potential at one point of time variable using the parabolic-type frequency function method. In [23], the authors proved a Hölder-type interpolation inequalities of unique continuation for fractional order parabolic equations with space-time dependent potentials on a thick set. ...

A uniform bound on costs of controlling semilinear heat equations on a sequence of increasing domains and its application

ESAIM Control Optimisation and Calculus of Variations

... For such an ideal state, it is necessary to study dynamical systems with discontinuous trajectories, which can also be called impulsive dynamic systems. In recent years, due to the needs of modern technology, impulsive control system and impulsive perturbation system have attracted more and more attention, and the application of impulse dynamical system in technical problems is increasingly extensive, such as [33,7,39,37,3,28,30,34,29,26]. As is known to all that time delay is ubiquitous in dynamical systems and engineering applications. ...

Constrained Approximate Null Controllability of The Coupled Heat Equation with Impulse Controls
  • Citing Article
  • September 2021

SIAM Journal on Control and Optimization

... In fact, the theory of minimum time impulse controls has been extensively used in various practical mathematical models, and has become an important research field in recent years. This can be found in a large number of literature (see [1,4,7,11,12,15,16,21,23,26,28,31]). ...

Minimal Time Impulse Control Problem of Semilinear Heat Equation

Journal of Optimization Theory and Applications

... This question is motivated by the literature [14], which studies a similar equation in a bounded convex domain. Extensive related references can be found in [2,5,9,13] and the rich works cited therein. Reference [16] studies the relationship between the observation region and observability for the linear heat equation in R n and shows that an observation region satisfies the observability inequality if and only if it is γ−thick at scale L for some γ > 0 and L > 0. To study this problem, we need to characterize suitable conditions for the observation region ω. ...

Observability Inequalities for the Heat Equation with Bounded Potentials on the Whole Space
  • Citing Article
  • July 2020

SIAM Journal on Control and Optimization

... For time-dependent systems, the control problem (1.1)-(1.2) posed in M(Ī c ; L 2 (ω)) yields controls with compact support in time. This characteristic allows for determining the optimal moments for control device actions, akin to a generalization of impulse control [31][32][33][34][35][36][37][38][39][40][41]. Recall that in impulse control problems, the control q in (1.1)-(1.2) is replaced by ...

Minimal Norm Control Problem Governed by Semilinear Heat Equation with Impulse Control

Journal of Optimization Theory and Applications

... For time-dependent systems, the control problem (1.1)-(1.2) posed in M(Ī c ; L 2 (ω)) yields controls with compact support in time. This characteristic allows for determining the optimal moments for control device actions, akin to a generalization of impulse control [31][32][33][34][35][36][37][38][39][40][41]. Recall that in impulse control problems, the control q in (1.1)-(1.2) is replaced by ...

Minimal Time Impulse Control of an Evolution Equation

Journal of Optimization Theory and Applications