• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.505-510
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• 1994

To prevent the stable states from the complex dynamics, the global behavior of the overall system must be considered. Thus, indirect adaptive scheme might result in needless responses. Discrete-time variable structure controllers for a well-known logistic map are designed for two deferent sliding hyperplanes. Impulse disturbances are fully rejected by tile virtue of discrete-time variable structure control(DVSC). A numerical example is given to illustrate the effectless of the DVSC.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.483-488
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• 1989

In this paper, the concept of persistent excitation(PE) is examed and the model reference adaptive control of a linear plant subjected to bounded disturbances is considered. Computer simulation reasults of nonlinear differential equations shows that the global behavior of the adaptive system depends upon the PE of the reference input as well as the amplitude of the external disturbances. The sufficient conditions on the PE of the reference input for the signals in the adaptive system to be globally bounded has been derived.

• Proceedings of the CALSEC Conference
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• 2005.03a
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• pp.272-277
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• 2005

The Web Services Choreogaphy Description Language (WS-CDL) is an XML-based language that describes peer-to-peer collaborations of parties by defining, from a global viewpoint, their common and complementary observable behavior; where ordered message exchanges result in accomplishing a common business goal. In this paper, we survey and analysis the functionality of the WS-CDL, and propose new language, which enhance the WS-CDL for the conversation the message between entities.

• Journal of the Korean Mathematical Society
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• v.57 no.1
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• pp.249-281
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• 2020

A reaction-diffusion model with spatiotemporal delay modeling the dynamical behavior of a single species is investigated. The parameter regions for the local stability, global stability and instability of the unique positive constant steady state solution are derived. The conditions of the occurrence of Turing (diffusion-driven) instability are obtained. The existence of time-periodic solutions, the existence and nonexistence of nonconstant positive steady state solutions are proved by bifurcation method and energy method. Numerical simulations are presented to verify and illustrate the theoretical results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2355-2361
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• 1996

Convergence analysis on Godard's quartic(GQ) algorithm used for blind equalization is accomplished in this paper. First, we explain the local behavior of the GQ algoithm around the global minimum point of the average performance function. Then we consider the geometry of the average performance function. The main result is that a good initial parameter vector of the GQ algorithm can be chosen based on the information of the geometry of the average performance function.

• Communications of the Korean Mathematical Society
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• v.23 no.1
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• pp.61-65
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• 2008

In this paper we prove that every positive solution of the third order rational difference equation $$x_{n+1}\;=\;\frac{{\beta}x_n\;+\;x_{n-2}}{A\;+\;Bx_n\;+\;x_{n-2}}$ converges to the positive equilibrium point $$\bar{x}\;=\;\frac{{\beta}\;+\;1\;-\;A}{B\;+\;1}$, where $0\;<\;{\beta}\;{\leq}\;B$, $1\;<\;A\;<\;{\beta}\;+\;1$

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.26 no.4
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• pp.224-243
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• 2022

In this paper, we prove the global existence of classical solutions to the 2D incompressible Boussinesq equations for the micropolar fluid. Furthermore, applying the Fourier splitting methods, we obtain the lager time decay properties.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.754-761
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• 2005

The 40\% of wall thickness criterion which has been used as a plugging rule of steam generator tubes is applicable only to a single cracked tube. In the previous studies performed by authors, several global failure prediction models were introduced to estimate the failure loads of steam generator tubes containing two adjacent parallel axial through-wall cracks. These models were applied for thin plates with two parallel cracks and the COD base model was selected as the optimum one. The objective of this study is to verify the applicability of the proposed optimum global failure prediction model for real steam generator tubes with two parallel axial through-wall cracks. For the sake of this, a series of plastic collapse tests and finite element analyses have been carried out fur the steam generator tubes with two machined parallel axial through-wall cracks. Thereby, it was proven that the proposed optimum failure prediction model can be used as the best one to estimate the failure load quite well. Also, interaction effects between two adjacent cracks were assessed through additional finite element analyses to investigate the effect on the global failure behavior.

• Asian Journal of Innovation and Policy
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• v.9 no.1
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• pp.95-105
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• 2020

Air pollution is a global challenge that not only threatens public health, but also takes away lives. Strategic communication, in other words, public relations, is an essential way of tackling air pollution and managing the risks involved. Engaging global citizens into the public sphere requires the building of a sense of collectivity and duty on achieving clean air. Strategies and policies on an international scale that are based on the theoretical framework (Behavior Procedure Model) and focus on leading citizens into the mature and unified Collectivity during the observance of the 'International Day of Clean Air for blue skies' are crucial. Notably, the Asian continent has inevitably found itself at the crossroad between economic growth and environmental protection, and has even been observed to be pursuing a passive response to air pollution. The key communication strategies are supported by the three goals, which include: expanding existing communities and building a new Collectivity, supporting international solidarity and individual member state activities, and implementing systems and structures. The key goals can be further specified into six strategies. This paper has analyzed global problems and discussed possible communication strategies to increase public engagement for the observation of the 'International Day of Clean Air for blue skies.' It will be the responsibility of all nations to implement the aforementioned strategies and policies as well as promoting global action.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.625-632
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• 2011

The ignition characteristics of a $CH_4$/hot air counterflow diffusion flame were investigated numerically using a flame-controlling continuation method. For the chemical reactions, the GRI-v1.2 reaction mechanism was used in the simulation. The maximum flame temperature was presented in the space of the inverse global strain rate, and showed S-curve-type behavior. The flame temperatures and velocities of the upper and middle branches were compared for different global strain rates. In addition, the global strain rate was compared with the local strain rates defined at the flame surface and the boundaries of the fuel and oxidizer sides of the fuel/air mixing layer. These local strain rates correlated well with the global strain rate.