• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4483-4501
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• 2015

In this paper, we investigate a security transmission scheme at the physical layer for cooperative wireless relay networks in the presence of a passive eavesdropper. While the security scheme has been previously investigated with perfect channel state information(CSI) in the presence of a passive eavesdropper, this paper focuses on researching the robust cooperative relay beamforming mechanism for wireless relay networks which makes use of artificial noise (AN) to confuse the eavesdropper and increase its uncertainty about the source message. The transmit power used for AN is maximized to degrade the signal-to-interference-plus-noise-ratio (SINR) level at the eavesdropper, while satisfying the individual power constraint of each relay node and worst-case SINR constraint at the desired receiver under a bounded spherical region for the norm of the CSI error vector from the relays to the destination. Cooperative beamforming weight vector in the security scheme can be obtained by using S-Procedure and rank relaxation techniques. The benefit of the proposed scheme is showed in simulation results.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.7
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• pp.881-886
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• 2005

This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent tile complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also, by using the power series, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of tile digitally controlled system are formulated in terms of linear matrix inequalities (LMIs). Finally, a TS fuzzy model for the chaotic Lorentz system is used as an example to guarantee the stability and effectiveness of the proposed method.

• The Korean Journal of Archival Studies
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• no.63
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• pp.167-225
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• 2020

The author conducted a records research named 'daily life and records.' The purpose of the research was to find an archive, if possible, that would be effective in promoting exchange and cooperation among people in their daily lives, and to distinguish what type of archive it would be, as well as how to let it naturally take place in their ordinary lives. For 4 months (August-December 2019) with 100 college students in their 20s, trial and error were repeated. There was no separate laboratory for the research, and it used regular school hours at universities. Although it is true that there was a control through power by the college system, the plot was centered on the sunshine policy. To human being there is a voluntary and positive attitude. If anyone begins to take this attitude it is difficult to stop such action. Through emotional support, this voluntary action was encouraged to take root. The experiment was an attempt to doubt the obvious, and to search for something new. From afar, this may seem irrelevant to archives. However, for the author who is a professional archivist, it was a time of records through control by Records principles. By organizing into a form of story, its archival implications are observed.