• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.107-109
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• 2007

The recently-developed off-line learning control approaches for the rejection of periodic disturbances utilize the specific property that the learning system tends to oscillate in steady state. Unfortunately, the prior works have not clarified how closely the learning system should approach the steady state to achieve the rejection of periodic disturbances to satisfactory level. In this paper, we address this issue extensively for the class of linear systems. We also attempt to remove the effect of other aperiodic disturbances on the rejection of the periodic disturbances effectively. In fact, the proposed learning control algorithm can provide very fast convergence performance in the presence of aperiodic disturbance. The effectiveness and practicality of our work is demonstrated through mathematical, performance analysis as well as various simulation results.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.947-952
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• 2002

A new concept of forming self-aligned multidomains is used for fabricating wide-viewing liquid crystal displays (LCDs) with periodic surface gratings.An array of the periodic surface gratings is produced on substrates using a photosensitive polymer by the illumination o. the UV light through a patterned photomask. A multidomain structure is naturally formed on the grating surface by the initial director distortions together with continuous variations of an external electric field. The LCD cells with periodic surface gratings are found to show excellent extinction in the off-state and wide-viewing property m the on-state.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.1
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• pp.113-120
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• 1999

In this paper, chaotic signals of a Chua's oscillator are effectively controlled to low periodic signal(1-periodic signal, 2-periodic signal, etc) or equilibrium point using the linear state feedback technique. The proposed linear state feedback technique has characteristics, that any solution of the Chua's oscillator can be a goal of the control(fixed point, periodic orbit, etc). The controller has a very simple structure, which does not require adjusting system parameters.

• Journal of the Korean Mathematical Society
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• v.16 no.2
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• pp.113-116
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• 1980

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1996-1999
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• 2002

Applying a higher frequency periodic control signal, a state of a chaotic pulse-train generator is quantized. The circuit has various co-existing super-stable periodic pulse-trains (ab. SSPTs) and generates one of them depending on the initial state. Also correlation characteristics of the SSPTs are analyzed precisely. We then consider application of the SSPTs to spread sequences of CDMA with pulse-train signals.

• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.26-30
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• 2011

Although the pathophysiologic mechanism is unknown, there has been long-running debate on whether periodic discharges such as periodic lateralized epileptiform discharges (PLEDs) and generalized periodic epileptiform discharges are an ictal or interictal EEG pattern. The goal of this review is to give evidence that such periodic discharges on EEG are not ictal phenomenon and just represent underlying acute brain damage. This review includes coma with epileptiform EEG pattern and its prognostic and therapeutic implications. Based on previous reports, rather than taking the view PLEDs represent either an underlying ictal process or an electrographic correlate of neuronal injury, it would be more reasonable that PLEDs are considered as a dynamic pathophysiological state in which unstable neurobiological processes create an ictal-interictal continuum.

• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.21-25
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• 2011

Periodic lateralized epileptiform discharges (PLEDs) had been debated whether it is ictal or non-ictal phenomenon. As most of PLEDs occur in patients with acute structural lesions, some epileptologists prefer PLEDS as a non-ictal phenomenon, rather an obscure epiphenomenon of etiological diseases. But, almost half of the patients with PLEDs do not have acute structural lesions in the brain and metabolic disorders or old CNS lesions may cause PLEDs and even more, no brain lesion was identified in some patients. There are many data supporting PLEDs as ictal phenomena. Occurrence of PLEDs usually accompanied by decreased mentality and is improved as PLEDs disappeared. Current SPECT study showed marked hyperperfusion in the lesion side of PLEDs, that is striking evidence of PLEDs as ictal phenomena. Also careful review of EEG with PLEDs revealed it is a dynamic process rather than a static state. Despite of these evidences, as PLEDs are an end-stage of animal status epilepticus models, it may be a transition of ictal to interictal state.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.225-228
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• 1992

The purpose of this project is the presentation of new method for selection of a scalar control of linear time-periodic system. The approach has been proposed by Radziszewski and Zaleski [4] and utilizes the quadratic form of Lyapunov function. The system under consideration is assigned either in closed-loop state or in modal variables as in Calico, Wiesel [1]. The case of scalar control is considered, the gain matrix being assumed to be at worst periodic with the system period T, each element being represented by a Fourier series. As the optimal gain matrix we consider the matrix ensuring the minimum value of the larger real part of the two Poincare exponents of the system. The method, based on two-step optimization procedure, allows to find the approximate optimal gain matrix. At present state of art determination of the gain matrix for this case has been done by systematic numerical search procedure, at each step of which the Floquet solution must be found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.311-316
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• 2012

In this paper, chaotic circuit of the Lorentz system for engineering applications was implemented using resistor, multipliers, capacitors and operational amplifiers. The implemented Lorentz chaotic system was analysed by PSPICE program. PSPICE simulation results show many kind of chaotic phenomena such time waveforms and phase plots. Meanwhile, according to resistor's variation, we got that Lorentz system show equilibrium state, periodic state and chaotic state.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.558-558
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• 1992