• Honam Mathematical Journal
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• v.34 no.1
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• pp.19-34
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• 2012

In this paper, we investigate the stability of a functional equation f(x+y+z)-f(x+y)-f(y+z)-f(x+z)+f(x)+f(y)+f(z) = 0 by using the fixed point theory in the sense of L. Cadariu and V. Radu.

• Honam Mathematical Journal
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• v.32 no.1
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• pp.29-43
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• 2010

In this note, by using the fixed point method, we prove the generalized stability for a mixed type functional equation in random normed spaces of which the general solution is either cubic or quadratic.

• Nuclear Engineering and Technology
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• v.30 no.4
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• pp.353-363
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• 1998

The H$_{\infty}$ algorithms of the mixed weight sensitivity is used for the robust design of the reactor power control system. The mixed weight sensitivity method requires the selection of the proper weighting functions for the loop shaping in frequency domain. The complexity of the system equation and the non-convexity of the problem make it very difficult to determine the weighting functions. The genetic algorithm which is improved and hybridized with the simulated annealing is applied to determine the weighting functions. This approach permits an automatic calculation and the resultant system shows good robustness and performance.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.194-197
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• 2005

In this work, a mixed beam approach is performed to identify the transverse shear behavior of thin-walled composite beams with closed cross-sections. The analytical model includes the effects of elastic couplings, shell wall thickness, and torsion warping. The distributions of shear flow across the section as well as the shear correction coefficients are obtained in a closed form in the beam formulation. The influence of transverse shear deformation on the static behavior of closed cross-section composite beams is also investigated in the analysis

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.3
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• pp.188-193
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• 1996

In this paper, an integrated navigation system based on GPS(Global Positioning System) and Dead-Reckoning (DR) is designed. For the calibration of DR, a self-calibration method and a GPS-based calibration method are proposed. From the field-test results, it is shown that DR can be successfully calibrated by the two proposed calibration methods. Also, a cascaded filter approach and a mixed-measurement algorithm are employed for GPS/DR integration. By using the newly proposed mixed-measurement algorithm, it is shown in simulation that the position error becomes smaller than by using only DR even if the number of visible GPS satellites is less than 4.

• Proceedings of the Korean Statistical Society Conference
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• 2002.11a
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• pp.141-146
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• 2002

In this article we consider the problem of constructing confidence intervals for a linear regression model with nested error structure. A popular approach is the likelihood-based method employed by PROC MIXED of SAS. In this paper, we examine the ability of MIXED to produce confidence intervals that maintain the stated confidence coefficient. Our results suggest the intervals for the regression coefficients work well, but the intervals for the variance component associated with the primary level cannot be recommended. Accordingly, we propose alternative methods for constructing confidence intervals on the primary level variance component. Computer simulation is used to compare the proposed methods. A numerical example and SAS code are provided to demonstrate the methods.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.109-124
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• 2001

This paper presents a new method that can efficiently solve the integrated problem of line balancing and model sequencing in mixed model assembly lines (MMALs). Line balancing and model sequencing are important for an efficient use of MMALs. The two problems of balancing and sequencing MMALs are tightly related with each other. However, In almost all the existing researches on mixed-model production lines, the two problems have been considered separately. In this research, an endosymbiotic evolutionary a1gorithm, which is a kind of coevolutionary a1gorithm, is adopted as a methodology in order to solve the two problems simultaneously. This paper shows how to apply an endosymbiotic evolutionary a1gorithm to solving the integrated problem. Some evolutionary schemes are used In the a1gorithm to promote population diversity and search efficiency. The proposed a1gorithm is compared with the existing evolutionary algorithms in terms of solution quality and convergence speed. The experimental results confirm the effectiveness of our approach.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.22-22
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• 2000

This study investigates the use of mixed $H_2/H_{\infty}$ and $\mu$-synthesis to construct a robust controller for the benchmark problem. The model treated in the problem is a coupled three-inertia system which reflects the dynamics of mechanical vibrations. We, first adopt the mixed $H_2/H_{\infty}$ the to design a feedback controller K(s). Next, $\mu$-synthesis method is applied to the overall system to make use of structured parametric uncertainty.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.675-685
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• 2013

Generation capacities and transmission line constraints in a competitive electricity market make it troublesome to compute Nash Equilibrium (NE) for analyzing participants' strategic generation quantities. The NE can cause a mixed strategy NE rather than a pure strategy NE resulting in a more complicated computation of NE, especially in a multiplayer game. A two-level hierarchical optimization problem is used to model competition among multiple participants. There are difficulties in using a mathematical programming approach to solve a mixed strategy NE. This paper presents heuristics applied to the mathematical programming method for dealing with the constraints on generation capacities and transmission line flows. A new formulation based on the heuristics is provided with a set of linear and nonlinear equations, and an algorithm is suggested for using the heuristics and the newly-formulated equations.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.11
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• pp.896-903
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• 2001

This study investigates the use of mixed $H_2/H_{$\infty}$ and $\mu$-synthesis to construct a robust controller for the benchmark problem. The model treated in the problem is a coupled three-inertial system that reflects the dynamics of mechanical vibrations. This kind of problem requires to be satisfied the robust performance (both in the time and frequency-domain specifications). We, first, adopt the mixed $H_2/H_{$\infty}$ theory to design a feedback controller K(s). Next, $\mu$-synthesis method is applied to the overall system to make use of structured parametric uncertainty. This process permits higher levels of controller authority and reduces the conservativeness of the controller. Finally, the feedforward controller is also used to improve the transient response of the output. We confirm that all design specifications except a complementary sensitivity condition can be achieved.