• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.61-76
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• 2002

The robust non-fragile guaranteed cost control problem is studied in this paper for class of uncertain linear large-scale systems with time-varying delays in subsystem interconnections and given quadratic cost functions. The uncertainty in the system is assumed to be norm-hounded arid time-varying. Also, the state-feedback gains for subsystems of the large-scale system are assumed to have norm-bounded controller gain variations. The problem is to design state feedback control laws such that the closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound far all admissible uncertainties. Sufficient conditions for the existence of such controllers are derived based on the linear matrix inequality (LMI) approach combined with the Lyapunov method. A parameterized characterization of the robust non-fragile guaranteed cost contrellers is 7iven in terms of the feasible solution to a certain LMI. Finally, in order to show the application of the proposed method, a numerical example is included.

• International Journal of Control, Automation, and Systems
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• v.5 no.3
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• pp.269-282
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• 2007

This paper presents a robust control method via the intelligent adaptive backstepping design technique for stable walking of nine-link biped robots with unknown model uncertainties and external disturbances. In our control structure, the self recurrent wavelet neural network(SRWNN) which has the information storage ability is used to observe the uncertainties of the biped robots. The adaptation laws for all weights of the SRWNN are induced from the Lyapunov stability theorem, which are used for on-line controlling biped robots. Also, we prove that all signals in the closed-loop adaptive system are uniformly ultimately bounded. Through computer simulations of a nine-link biped robot with model uncertainties and external disturbances, we illustrate the effectiveness of the proposed control system.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.2
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• pp.121-127
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• 2009

This paper deals with the design problem of robust stabilization and non-fragile controller for discrete-time singular systems with parameter uncertainties and time-varying delays in state and input by delay-dependent Linear Matrix Inequality (LMI) approach. A new delay-dependent bounded real lemma for singular systems with time-varying delays is derived. Robust stabilization and robust non-fragile state feedback control laws are proposed, which guarantees that the resultant closed-loop system is regular, causal and stable in spite of time-varying delays, parameter uncertainties, and controller gain variations. A numerical example is given to show the validity of the design method.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2081-2083
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• 2001

In this paper, without mathematical modeling dynamics, the plant parameter in sliding mode are estimated by the indirect adaptive fuzzy control. Adaptive laws for fuzzy parameters and fuzzy rule structure are established so that the whole system is stable in the sense of Lyapunov stability. The computer simulation results for inverted pendulum system show the performance of the proposed fuzzy sliding mode controller.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.117-121
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• 2021

Multi-crew Pilot License (MPL) is an international pilot certification adopted by the International Civil Aviation Organization (ICAO) in 2006 under the recognition of the need for efficient and systematic pilot training including the education of pilots with advanced aviation technology and ability to respond to flight environment, resolution of the human factor problems of pilots, and provision of stable training tools for transport aircraft pilots for potential risk of pilot shortage in the future. South Korea also has prepared a legal basis for operating an MPL system in the Aviation Act in 2009, but there has been no domestic MPL qualifier. The biggest reason for this seems to be the insufficient domestic MPL training system. Therefore, it is necessary to benchmark the international standards of the ICAO, and to promote the development of the Korean MPL training system through revision and supplementation of laws and regulations in consideration of Korean circumstances.

• Journal of Arbitration Studies
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• v.17 no.3
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• pp.31-56
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• 2007

The purpose of this thesis lies on building the foundation for the further activation of trade among the Northeast Asian countries such as South Korea, Japan, China, Russia, and North Korea through an analytical comparison of their arbitration systems. Further activation of trade cannot be reached without previously building safety measures on the negotiation of exports, the control on defective imported merchandise, the returns on investments, and the stable management of businesses. Throughout this thesis an analytical comparison of these five countries' most important areas on arbitration will be carried out. These areas are the arbitration laws and organizations; the structures of the laws; scope of arbitration; form of arbitration agreement, appointment of arbitratiors, place of arbitration, hearing, court assistance in taking evidence, governing law, decision making by panel of arbitrators, form and contents of awards, effective of award, recourse against award, recognition and enforcement of awards. etc. It was found in each of the areas cases to be identical, similar or verydifferent; also, cases unable to arbitrate. This phenomenon was found to occur due to the differences in political and economic systems and perception of arbitration among these countries. Additionally, this thesis points out what should each country do for its integration. It is also suggested the organization of a common arbitration research body to continue the efforts for raising the awareness, building trust, and mutual recognition among the countries to ultimately create a common arbitration system. Lastly, it is a personal will that this thesis will serve as the starting point for in depth researches in each of the presented areas.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.604-613
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• 2002

Generation characteristics of electrospray droplets for highly viscous liquid have been investigated by measuring size distributions of droplets emitted from the Taylor cone using glycerol solutions with various conductivities. Because of very small volatility of glycerol, droplet sizes can be measured by an aerodynamic size spectrometer (TSI Aerosizer DSP) with negligible evaporation of droplets. For highly conducting and viscous liquid, the sizes of the droplets electrosprayed from the Taylor cone are found to be relatively insensitive to applied voltages and the electrosprays assisted by the corona discharge call produce monodisperse droplets as long as the corona intensity is not too high. Near the minimum flow rate where a liquid cone is stable, the spray tends to consist of a one -peak monodisperse distribution of drop lets. However, at high flow rates, the spray bifurcates into bimodal distributions, which are consistent with the result of the previous study for less viscous liquids than our liquids. For liquid flow rates (Q) below 1 nl/s, the measured droplet diameters by the aerosizer are in the range of 0.30 to 1.2 ${\mu}{\textrm}{m}$ for the glycerol solutions. The diameters of monodisperse droplets scale approximately with $r^*=Q_$\tau$(Q$\tau$){^1/3}$ where $r^*$ is a characteristic length and $\tau$is the electrical relaxation time of the fluid. However, when compared with several represe ntative scaling laws, the droplet diameters are two to six factors greater than those predicted by the scaling laws. This may be closely related to the combined effect of the much higher viscosity and the electrical charge on the jet breakup of glycerol so solution.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.99-99
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• 2011

Fuel cell systems are a completely different form of electricity source that has been used so far and is an aggregation of multiple technologies with multidisciplinary features that can be operated safely only when gas and electrical safety are being considered. Since fuel cells generate through electrochemical reactions there are difficulties in ensuring electricity safety, power quality assessment, effective control and reliability standards for system faults using conventional inspection techniques and even though they are necessary as a primary means for reduction of CO2 owing to the Climate Convention, electrical safety assessment and measures are required for the prevention of faults in residential facilities. Although small-scaled distributed power supplies can be utilized as important means of peak control and energy management measures, research is required for observing the effects on the system and the development of inspection technology to ensure stable operation, and the electrical safety of residential fuel cell systems need to be assessed and the problems derived for establishing electrical safety standards. From the year 2002, Japan has established laws on technical safety standards and development and rules on the product specifications and standards for the industrialization of hydrogen fuel cells. Also, a lot of effort have been made for the commercialization of fuel cells by building one-stop certification services. Internationally, the IEC TC 105 has established international standards based on fuel cells. In order to protect the national interest, the country should be able to respond accordingly meet global standards. In fact, in Korea, to comply with the international trend, Korea Energy Management Corporation is establishing a certified agenda for fuel cells and Korean Agency for Technology and Standards is enacting technical standards for fuel cells. The current terms of fuel cells are that research has been focused more on the quality and performance of manufactured products rather than stable power operation and maintenance over time. In this paper, by considering the household fuel cell as a power device, the safety standards of the fuel cell system for a reliable operation with the existing power system is being proposed.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.85-91
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• 2016

This study is related with support system plans of public-private convergence for emergency recovery services to fire victims. The current issues are analysed from the condition and problem analysis results of emergency recovery activities for fire victims. And building plans of an integrated support system based on the government and private sector cooperation are proposed. Overall, the system shows that the government is responsible for the functionality of management and supervision for the system operation, and the private is responsible for the functionality of specialized agencies for practical emergency recovery. Consequently, support system plans include with infrastructure maintenance of laws and regulations, contracting-out of the support system, stable supply of operating budget and function strengthening of public-private convergence for emergency recovery. Especially, plan for stable supply of operating budget in detail including with establishment of the fund and self-financing composition of private corporations for emergency recovery services is proposed. The results of this study will lead strengthening of fire safety welfare and social safety nets at future.

• Journal of Korea Water Resources Association
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• v.47 no.11
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• pp.1061-1066
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• 2014

A stable second-order finite volume method was proposed to predict sediment transport under rapidly varied flow conditions such as transcritical flow. For the use under unsteady flow conditions, a sediment transport model was coupled with shallow water equations. HLLC approximate Riemann solver based on a monotone upstream-centered schemes for conservation laws (MUSCL) reconstruction was used for the computation of the flux terms. From the comparisons of dam break flow experiments on erodible beds in one- and two-dimensional channels, good agreements were obtained when proper parameters were provided. Lastly, dam surface erosion problem by overtopped water was simulated. Overall, the numerical solutions showed reasonable results, which demonstrated that the proposed numerical scheme could provide stable and physical results in the cases of subcritical and supercritical flow conditions.