• Journal of applied mathematics & informatics
• /
• v.25 no.1_2
• /
• pp.231-244
• /
• 2007

In this paper, we use measure theory for considering asymptotically stable of an autonomous system [1] of first order nonlinear ordinary differential equations(ODE's). First, we define a nonlinear infinite-horizon optimal control problem related to the ODE. Then, by a suitable change of variable, we transform the problem to a finite-horizon nonlinear optimal control problem. Then, the problem is modified into one consisting of the minimization of a linear functional over a set of positive Radon measures. The optimal measure is approximated by a finite combination of atomic measures and the problem converted to a finite-dimensional linear programming problem. The solution to this linear programming problem is used to find a piecewise-constant control, and by using the approximated control signals, we obtain the approximate trajectories and the error functional related to it. Finally the approximated trajectories and error functional is used to for considering asymptotically stable of the original problem.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.3
• /
• pp.213-220
• /
• 2008

The object of this paper is to propose a method to deal with the problem of modeling user specifications in approaches based on supervisory control and Petri nets. However, most of Petri Net approaches are based on forbidden states specifications, and these specifications are suitable the use of tool such as the reachability graph. But these methods were not able to show the user specification easily and these formalisms are generally limited by the combinatorial explosion that occurs when attempting to model complex systems. Herein, we propose a new efficient method using FSSTP (Forbidden Sequences of State-Transitions Problem) and theory of region. Also, to detect and avoid the deadlock problem in control process, we use DAPN method (Deadlock Avoidance Petri nets) for solving this problem in control model.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.76.5-76
• /
• 2002

In this paper, we provide a Nash solution to predictive control problem for nonminimum phase singular nonlinear systems. Until now, there is no result on predictive control problem for this class of nonlinear systems. Chen's recent work considered predictive control problem for a class of nonlinear systems with ill-defined relative degree. Since his work is not a result considered in the feedback linearization framework, there is no a result on singular probem in his paper. In contrast to the existing predictive control result, our work considers two main obstacles (singularity and nonminimum phase) in the feedback linearization framework. For a generally formu...

• 제어로봇시스템학회:학술대회논문집
• /
• 1988.10b
• /
• pp.896-900
• /
• 1988

Tree search can be applied to a control problem if the system is a discrete-time one and if the control input takes only discrete values. This paper considers the application of heuristic tree search to a simple control problem. The results of simulation studies show the good possibility of this approach to a control problem.

• Journal of applied mathematics & informatics
• /
• v.18 no.1_2
• /
• pp.1-23
• /
• 2005

The decentralized static output feedback design problem is considered. A constrained trust region method is developed that solves this optimal control problem when a complete set of state variables is not available. The considered problem is interpreted as a non-linear (non-convex) constrained matrix optimization problem. Then, a decentralized constrained trust region method is developed for this problem class exploiting the diagonal structure of the problem and using inexact computations. Finally, numerical results are given for the proposed method.

• Management Science and Financial Engineering
• /
• v.20 no.2
• /
• pp.1-5
• /
• 2014

The robust inventory control problem was proposed and solved by Bertsimas and Thiele (2006). Their results are very interesting in that the problem can be solved easily and also the solution possesses nice properties of those found in the traditional stochastic inventory control problem. However, their formulation is shown to be incorrect, which invalidates all of the results given there. In this paper, we propose an alternative formulation of the problem which uses a different but practically applicable uncertainty set. Under the newly proposed model, all of the useful properties given in Bertsimas and Thiele (2006) will be shown to be valid.

• Honam Mathematical Journal
• /
• v.26 no.4
• /
• pp.423-439
• /
• 2004

We are concerned with the robust control problem for the Keller-Segel equations with the distributed control and disturbance. We consider the present problem as a differential game finding the best control which takes into account the worst disturbance. We prove the existence of solutions and the optimality conditions to a corresponding problem.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.1
• /
• pp.25-34
• /
• 2000

In this paper, we design a H^\infty servo controller for gauge control of tandem cold mill. To improve the performance of the AGC(Aotomatic Gauge Control) system based on the Taylor linearized model of tandem cold mill, the H^\infty servo controller is designed to satisfy robust stability, disturbance attenuation and robust tracking properties. The H^\infty servo controller problem is modified as an usual H^\infty control problem, and the solvability condition of the H^\infty servo problem depends on the solvability of the modified H^\infty control problem. Since this modified problem does not satisfied standard assumptions for the H^\infty control problem, it is solved by an LMI(Linear Matrix Inequality) technique. Consequently, the comparison between the H^\infty servo controller and the existing PID/FF(FeedForward) controller shows the usefulness of this study.

• Korean Journal of Human Ecology
• /
• v.13 no.4
• /
• pp.485-496
• /
• 2004

The purpose of this study is to examine how the difference of parents' verbal control styles influence children's perspective-taking and interpersonal cognitive problem-solving skills. The subjects of this study were 117 five-year-old children with their parents included. The questionnaire used was relevant to the topic, such as parents' verbal control styles, young children's perspective-taking ability, and their interpersonal cognitive problem-solving skills. The percent, mean, standard deviation, three-way ANOVA, and Scheffe were used to analyze the data collected through SPSS WIN program. The major findings are as follows: First, a father's verbal control style makes a significant difference in young child's perspective-taking ability. However, there is no interaction effect between parents' verbal control styles and a child's sex. Second, a father's verbal control style makes a significant difference in young child's interpersonal cognitive problem-solving skills. Character-oriented verbal control mode of a father, in particular, produces more effects on boys than girls. Lastly, Two skills - alternative problem-solving skills and cause-solving skills - have interaction effects. Boys demonstrate higher skills than girls when parents apply character-oriented verbal control styles. Girls do so when mothers use position-oriented verbal control styles, especially in the area of cause-solving skills.

• Journal of the Korean Mathematical Society
• /
• v.41 no.4
• /
• pp.681-715
• /
• 2004

Mathematical formulation and numerical solutions of an optimal Dirichlet boundary control problem for the Boussinesq equations are considered. The solution of the optimal control problem is obtained by adjusting of the temperature on the boundary. We analyze finite element approximations. A gradient method for the solution of the discrete optimal control problem is presented and analyzed. Finally, the results of some computational experiments are presented.