• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.1-9
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• 2015

Stability criterion and its calculation are the crucial issue in the application of sail-assisted ship. However, there is at present no specific criterion and computational methods for the stability of sail-assisted ship. Based on the stability requirements for seagoing ships, the stability criterion of the sail-assisted ships is suggested in this paper. Furthermore, how to calculate the parameters and determine some specific coefficients for the ship stability calculation, as well as how to redraw stability curve are also discussed in this paper. Finally, to give an illustration, the proposed method is applied on a sail assisted-ship model with comments and recommendations for improvement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.41-45
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• 1997

To design a control system, it is a elementary point that the stability of the system should be guaranteed. Also, the phase of the system plays an important role for its frequence performance. In this paper, we present two stability criterion of repetitive control system with phase-lead and lag compensator. First, the stability criterion for the servo control system with phase-lead and lag compensator is shown by using small-gain theorem. Second, for the repetitive control system with the compensator, the stability criterion, also, is determined by using small-gain theorem. Two stability criterions show the same results that the stability depends on a coefficient of the phase-lead and lag compensator under some condition in servo control system and repetitive control system.

• International Journal of Control, Automation, and Systems
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• v.3 no.4
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• pp.580-590
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• 2005

In this paper, we propose a new stability criterion and a controller design method for switched linear systems. The proposed stability criterion is applicable to each subsystem independently without the need to consider the overall system. The controller can be easily designed through geometric relations between eigenvalues of each subsystem matrix. The proposed methods provide a systematic and simple pole assignment approach for switched linear systems. Illustrative examples are given.

• Wind and Structures
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• v.6 no.2
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• pp.151-164
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• 2003

On the basis of the first Lyapunov stability theory, this paper develops a dynamic stability criterion for elastic structural systems under arbitrary dynamic loads, and shows the stability criterion using energy variation. After the dynamic stability criterion is validated through a classic example, it is used for the dynamic stability investigation of practical guyed masts under random wind loads. The criterion is reliable, simple and of advantage for structures with large number of elements and nodes. The slack guys and internal resonance between guys and mast are two main factors which induces the dynamic instability of guyed masts, at the same time, some dynamic stability characteristics of guyed masts are found.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.92-94
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• 2004

In the previous work, we proposed a new stability criterion for the stability of switched linear systems. By the proposed criterion, we could simply check the stability of switched linear systems because the criterion is applicable to each individual subsystem without need to consider the overall system. Using this criterion, we provided the methods that design a state feedback control when full states are available. In this paper, we apply the same criterion to the case when full states are not available. Unlike existing method such as dwelling time analysis, the proposed method is suitable to a fast switching process because there is no need to consider dwelling time. And we can easily achieve designing multi-controller, multi-estimator, and the supervisor by means of the proposed method.

• Journal of Power Electronics
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• v.14 no.1
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• pp.143-155
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• 2014

The stability issues of a multi-module distributed DC power system without current-sharing loop are analyzed in this study. The physical understanding of the terminal characteristics of each sub-module is focused on. All the modules are divided into two groups based on the different terminal property types, namely, impedance (Z) and admittance (Y) types. The equivalent circuits of each group are established to analyze the stability issues, and the mathematical equations of the equivalent circuits are derived. A generalized criterion for multi-module distributed systems is proposed based on the stability criterion in a cascade system. The proposed criterion is independent of the power flow direction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.620-624
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• 2011

This paper propose a new delay-dependent stability criterion of neutral time-delay systems. By employing double-integral terms in augmented states and constructing a new Lyapunov-Krasovskii's functional, a delay-dependent stability criterion is established in terms of Linear Matrix Inequality. Through numerical examples, the validity and improvement results obtained by applying the proposed stability criterion will be shown.

• Geomechanics and Engineering
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• v.10 no.1
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• pp.59-76
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• 2016

The non-linear Hoek-Brown failure criterion has been widely accepted and applied to evaluate the stability of rock slopes under plane-strain conditions. This paper presents a kinematic approach of limit analysis to assessing the static and seismic stability of three-dimensional (3D) rock slopes using the generalized Hoek-Brown failure criterion. A tangential technique is employed to obtain the equivalent Mohr-Coulomb strength parameters of rock material from the generalized Hoek-Brown criterion. The least upper bounds to the stability number are obtained in an optimization procedure and presented in the form of graphs and tables for a wide range of parameters. The calculated results demonstrate the influences of 3D geometrical constraint, non-linear strength parameters and seismic acceleration on the stability number and equivalent strength parameters. The presented upper-bound solutions can be used for preliminary assessment on the 3D rock slope stability in design and assessing other solutions from the developing methods in the stability analysis of 3D rock slopes.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.467-477
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• 2008

In this paper, we provide a criterion for Chow stability in terms of log canonical threshold of the Chow form in the Grassmannian.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.2
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• pp.97-102
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• 2009

In this paper, the problem of stability analysis for networked control systems with norm-bounded parameter uncertainties is investigated. By construction Lyapunov's functional, a new delay-dependent stability criterion for uncertain networked control system is established in terms of LMIs (linear matrix inequalities) which can be easily by various convex optimization algorithms. One numerical example is included to show the effectiveness of proposed criterion.