• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.425-428
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• 1998

This paper proposes a new fuzzy controller using variable structure control theory. In this paper, after the time-varying fuzzy sliding surface is designed, the fuzzy rules are defined based on the variable structure control theory. This design method makes the fuzzy controller design more structured and can guarantee the stability and robustness of the fuzzy controller and overcome the shortcoming of the variable structure system. Through computer simulation and experiment of nonlinear inverted pendulum system, this thesis demonstrate that system has the robustness against disturbance and modelling error, and the tracking performance of it is improved.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.617-622
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• 2000

In this paper proposed is an $H_{\ifty}$ based flow controller for the ATM networks. The round trip time-delay uncertainty is taken into account and robustness of the proposed controller is analyzed. Maximum allowable time-delay uncertainties are computed with different weightings on performance and robustness. And discussed is a time-domain implementation method of the proposed controller. Time domain simulation with realistic environment demonstrates that the performance of the proposed controller is much better than that of conventional one.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.577-580
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• 1996

LQ-servo is a stability-robustness guaranteed multivariable controller design method based on the LQR structure to improve command following performance with output feedback. In this paper, a new type of PI controller based on LQ-servo is introduced. Then, Command following performance is improved using the limiting behavior of the control gain and weighting factors on the low frequency part of design parameter Q that is the state weighting matrix in the cost function.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.167-169
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• 2005

This paper proposes an optimum tuning which improves the tuning effect of IMC-PID and guarantees the performance and robustness of controller system by considering gain margin, phase margin, sensitivity functions and integral square error(ISE) for IMC-PID controller.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.237-237
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• 2000

In this paper, The modified dead-time compensator for plants with an integrator and long dead time is proposed. The design procedure takes account of the closed-loop performance and robustness. The tuning of the controller can be done using some information about the plant and its uncertainties. The proposed controller is compared to others recently presented in the literature. Some simulation results verify good closed-performance and robustness of the proposed DTC.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2060-2066
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• 2002

The closed-loop state and input observer is a pole-placement type observer and estimates unknown state and input variables simultaneously. Pole-placement type observers may have poor transient performance with respect to ill-conditioning factors such as unknown initial estimates, round-off error, etc. For the robust transient performance, the effects of these ill-conditioning factors must be minimized in designing observers. In this paper, the transient performance of the closed-loop state and input observer is investigated quantitatively by considering the error bounds due to ill-conditioning factors. The performance indices are selected from these error bounds and are related to the observer robustness with respect to the ill -conditioning factors. The closed-loop state and input observer with small performance indices is considered as a well-conditioned observer from the transient perspective.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2067-2072
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• 2002

The closed-loop state and input observer is a pole-placement type observer and estimates unknown state and input variables simultaneously. Pole-placement type observers may have poor performances with respect to modeling error and sensing bias error. The effects of these ill-conditioning factors must be minimized for the robust performance in designing observers. In this paper, the steady-state performance of the closed-loop state and input observer is investigated quantitatively and is represented as the estimation error bounds. The performance indices are selected from these error bounds and are related to the robustness with respect to modeling errors and sensing bias. By considering both transient and steady-state performance, the main performance index is determined as the condition number of the eigenvector matrix based on $L_2$-norm.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.229-236
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• 2023

As the importance and dependency of the positioning, navigation, and timing (PNT) information provided by the radio navigation satellite service (RNSS) increases, the vulnerability of RNSS to jamming can lead to significant risks. The signal design under the consideration of anti-jamming performance helps to provide service which is robust to jamming environment. Therefore, it is necessary to evaluate the jamming robustness performance during the design of new signals. In this paper, we introduce figures-of-merit (FoMs) that can be used for an anti-jamming performance analysis of designed signals of interest. We then calculate the FoMs, such as the quality factor (Q factor), tolerable jamming-to-signal ratio (tolerable J/S), and range to jammer (d) for legacy RNSS signals and analyze the results. Finally, based on the results of the analysis, we derive waveform design conditions to obtain good anti-jamming performance. As a result, this paper shows that the waveforms with wide bandwidth leading to good spectral efficiency provide strong anti-jamming performance.

• Korean small business review
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• v.43 no.2
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• pp.1-30
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• 2021

This study is to analyze the relationship between supply chain resilience antecedent factors, supply chain resilience and business performance. Supply chain integration, risk management activity, and visibility were selected as the preceding factors of supply chain resilience, and the effect of these factors on agility and robustness as supply chain resilience, and the effects of agility and robustness factors on corporate management performance are studied. To this end, a survey was conducted on Korean manufacturing companies, and a total of 124 questionnaires were used for the study. As a result of the testing of the research hypothesis, supply chain integration, risk management activity, and visibility have a positive (+) significant effect on agility and robustness. In addition, agility had a positive (+) effect on corporate management performance. But robustness had a positive (+) effect on corporate management performance, but not significant. In order for manufacturing companies to secure supply chain resilience through such research hypothesis testing, it is necessary to secure supply chain integration, risk management activity, and visibility capabilities. It was confirmed that agility and visibility capability can be linked to corporate management performance. In addition, the overall relationship structure between the preceding factors of supply chain resilience, supply chain resilience, and business performance was presented.