• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2927-2929
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• 2000

정보보호를 위해 비연성 디지털 워터마킹 방법으로 웨이브릿 변환을 많이 사용하고 있다. 본 연구에서는 여러 웨이브릿 변환인 드비시(Daubechies)변환, Coiflets 변환, Symlets 변환과 biorthogonal 변환등을 이용하여 비연성 디지털 워터마킹기법을 구성하고 각 변환의 특징과 성능비교를 한다. 공격의 형태는 dct변환 압축에 의한 영향에 의한 워터마킹의 보존여부에 관하여 고찰한다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.11
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• pp.503-509
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• 2002

In this paper, the robust non-fragile guaranteed cost control problem is studied for a class of linear large-scale systems with uncertainties and a given quadratic cost functions. The uncertainty in the system is assumed to be norm-bounded and 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 a 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 for all admissible uncertainties and controller gain variations. 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 controllers is given in terms of the feasible solutions to a certain LMI. A numerical example is given to illustrate the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.5
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• pp.8-17
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• 2002

This paper considers the problems of robust decentralized control for uncertain discrete-time large-scale systems with delays in interconnections and state feedback gain perturbations. Based on the Lyapunov method, the state feedback control design for robust stability is given in terms of solutions to a linear matrix inequality (LMI), and the measure of non-fragility in controller is presented. The solutions of the LMI can be easily obtained using efficient convex optimization techniques. A numerical example is included to illustrate the design procedures.