• East Asian mathematical journal
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• v.17 no.2
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• pp.375-383
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• 2001

In this paper we deal with the duality theory of optimality for an optimal control problem governed by a class of second order evolution equations. First we establish the dual control systems by using conjugate functions and then associate them to the original optimization problem.

• Research in Community and Public Health Nursing
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• v.29 no.1
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• pp.97-107
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• 2018

Purpose: A mediated model of Korean college students' problem gambling based on Blaszczynski and Nower's pathway model is developed and tested to explore mediating roles of self-control and irrational gambling beliefs in the association between emotionally vulnerable variables and problem gambling. Methods: 273 student participants recruited from 4 universities in Seoul and Gyeonggi, Korea responded. Data were collected with a structured self-report questionnaire comprising measures of problem gambling, depression, anxiety, coping styles, irrational gambling belief, and self-control. Results: The modified research model provides a reasonable fit to the data. Depression, anxiety, reflective coping, irrational beliefs, and self-control turned out to have direct effects on problem gambling, while indirect effects were reported in some suppressive and reactive styles. These predictors account for 38% of the college students' problem gambling. Conclusion: The findings suggest that developing intervention programs for reducing depression, anxiety, irrational gambling beliefs, and increasing reflective coping and self-control are needed to prevent Korean college students'problem gambling.

• Journal of applied mathematics & informatics
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• v.9 no.2
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• pp.717-730
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• 2002

In this paper we use measure theory to solve a wide range of the nonlinear programming problems. First, we transform a nonlinear programming problem to a classical optimal control problem with no restriction on states and controls. The new problem is modified into one consisting of the minimization of a special linear functional over a set of Radon measures; then we obtain an optimal measure corresponding to functional problem which is then approximated by a finite combination of atomic measures and the problem converted approximately to a finite-dimensional linear programming. Then by the solution of the linear programming problem we obtain the approximate optimal control and then, by the solution of the latter problem we obtain an approximate solution for the original problem. Furthermore, we obtain the path from the initial point to the admissible solution.

• Management Science and Financial Engineering
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• v.16 no.3
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• pp.95-102
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• 2010

This paper considers the robust inventory control problem introduced by Bertsimas and Thiele [4]. In their paper, they have shown that the robust version of the inventory control problem can be solved by solving a nominal inventory problem which is formulated as a mixed integer program. As a proper generalization of the model, we consider the problem with non-stationary cost. In this paper, we show that the generalized version can also be solved by solving a nominal inventory problem. Furthermore, we show that the problem can be solved efficiently.

• Journal of the Korean Home Economics Association
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• v.43 no.2
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• pp.1-17
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• 2005

The purposes of this study were to show general trends in the degree of parental monitoring, self-control and problem behavior perceived by adolescents and to examine possible changes in such trends in accordance with gender of adolescents and mother's employment, and then to determine the effects of these variables on adolescents' problem behavior. The subjects were 1288 adolescents of middle school in Busan (male 661, female 627). The main results were as follow. (1) General trends in the degree of internalizing problems and total behavior problems showed that girls had more problem behaviors than boys. (2) Boys and girls with unemployed mother perceived more parental monitoring than ones with employed mothers. Boys with unemployed mother had more self-control than ones with employed mothers. Boys with employed mother showed more problem hehaviors than ones with unemployed mother. (3) Mother's employment, the degree of parental monitoring and self-control had a significant indirect effect on internalizing problems, externalizing problems and total behavior problems. (4) The degree of self-control was the most powerful predicator of problem behaviors of middle school students.

• Journal of Ocean Engineering and Technology
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• v.26 no.3
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• pp.20-25
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• 2012

In this paper, the authors propose a new approach to the control problem of marine vessels that are moored or controlled by actuators. The vessel control system is basically based on Dynamic Positioning System (DPS) technology. The main object of this paper is to obtain a more useful control design method for DPS. In this problem, the control allocation is a complication. For this problem, many results have been given and verified by other researchers using a two-step process, with the controller and control allocation design processes carried out individually. In this paper, the authors provide a more sophisticated design solution for this issue. The authors propose a new design method in which the controller design and control allocation problems are considered and solved simultaneously. In other words, the system stability, control performance, and allocation problem are unified by an LMI (linear matrix inequality) based on control theory. The usefulness of the proposed approach is verified by a simulation using a supply vessel model.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1539-1544
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• 1991

In this paper we formulate and solve a generalized $H^{\infty}$ control problem. The conventional formulation of $H^{\infty}$ problem has some constraints in application, e.g. it can not deal with the servo problem. This is due to the superfluous requirement of internal stability of the augmented system. In this paper, we alleviate the stability of the augmented system to admit pole-zero cancellation on the imaginary aids outside the feedback loop of G22 and K. After such generalization, the servo problem is naturally incorporated into the $H^{\infty}$ synthesis.is.

• Bulletin of the Korean Mathematical Society
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• v.35 no.2
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• pp.325-338
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• 1998

Some nonlocal boundary value problems which arise from a feedback control problem are considered. We give a precise statement of the mathematical problems and then prove the existence and uniqueness of the solutions. We consider the Dirichlet type boundary value problem and the Neumann type boundary value problem with nonlinear boundary conditions. We also provide a regularity results for the solutions.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.413-418
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• 1991

Two methods are applied to the problem of trajectory optimization for launch vehicles which burn solid propellant. One is 'Optimal Control' theory, the other is 'NonLinear Programming' method. Trajectory optimization for solid rocket motors has a special problem. The special problem is that the payload of launch vehicle is not the function of control variable. This paper deals with this special problem.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.481-488
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• 1998

The drift and inter-story drift control method for steel structures subjected to seismic forces is formulated into a structural optimization problem in this paper. The formulated optimization problem with constraints on drift, inter-story drifts, and member strengthes are transformed into an unconstrained optimization problem. For the solution of the tranformed optimization problem an searching algorithm based on the gradient projection method utilizing gradient information on eigenvalues and eigenvectors are developed and presented in detail. The performance of the proposed algorithm is demonstrated by application to drift control of a verifying example.