PID control schemes based on classical control theory, have been widely used for real control systems. Further, there are a lot of researches on control schemes of tuning PID gains. Also several self-tuning and autotu...
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PID control schemes based on classical control theory, have been widely used for real control systems. Further, there are a lot of researches on control schemes of tuning PID gains. Also several self-tuning and autotuning techniques in the PID control systems have been reported for systems with unknown parameters. However, to the best of our knowledge, there is no result for discrete-time systems with unknown time-delays. On the other hand, a generalized predictive control scheme has been reported as a useful self-tuning control technique for unknown time-delay systems. In this paper, we present a self-tuning PID control algorithm for unknown time-delay systems based on minimization of a GPC criterion. Furthermore, we illustrate a numerical simulation result in order to show the effectiveness of this method.
Numerical results are presented in detail for the effective propagation constant of a space where many small spheres with high permittivity are randomly distributed, on the basis of the multiple scattering theory. The...
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Numerical results are presented in detail for the effective propagation constant of a space where many small spheres with high permittivity are randomly distributed, on the basis of the multiple scattering theory. The results are valid also for the space where the results given by conventional methods become invalid.< >
Presents the effective permittivity of the discrete random medium where dielectric spheres are randomly distributed for a coherent field, in the region of low to resonance frequencies. In addition, the authors have in...
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Presents the effective permittivity of the discrete random medium where dielectric spheres are randomly distributed for a coherent field, in the region of low to resonance frequencies. In addition, the authors have in part compared the results with those of the effective field approximation, the quasi-crystalline approximation and the quasi-crystalline approximation and coherent potential.
The authors have observed that the fibrinolytic process in strong magnetic fields up to 8 T was enhanced. In this study, they focused on the mechanism of this phenomenon. First, they observed that gradient magnetic fi...
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The authors have observed that the fibrinolytic process in strong magnetic fields up to 8 T was enhanced. In this study, they focused on the mechanism of this phenomenon. First, they observed that gradient magnetic fields eroded a fibrin gel in a specific direction. Second, they carried out an experiment to measure concentrations of fibrin in magnetic fields and concluded that redistribution of fibrin polymers concentration occurred in gradient magnetic fields up to 8 T.< >
This study focuses on the investigation of higher brain function using electroencephalogram (EEG) and magnetoencephalogram (MEG) techniques. The authors observed verbal cognitive activities by measuring EEGs and MEGs ...
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This study focuses on the investigation of higher brain function using electroencephalogram (EEG) and magnetoencephalogram (MEG) techniques. The authors observed verbal cognitive activities by measuring EEGs and MEGs evoked by visually cognitive tasks. English words, meaningless sets of letters, and simple flashes were presented. The authors analyzed the EEG and MEG data with a subtraction technique and topographic maps. Visual evoked potentials (VEPs) associated with cognition of meanings were obtained by subtracting VEPs evoked by random letters from VEPs evoked by English words. The topographic EEG maps in several subjects show a clear interhemispheric difference between latencies of 300 and 600 msec. The EEG maps in a few subjects, however, show no interhemispheric differences.< >
Here, the authors investigate a source model which is used in inverse problems of magnetoencephalography (MEG) or electroencephalography (EEG). A source model with a 2-dimensional spread which corresponds to the surfa...
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Here, the authors investigate a source model which is used in inverse problems of magnetoencephalography (MEG) or electroencephalography (EEG). A source model with a 2-dimensional spread which corresponds to the surface of the cortex is proposed. The spread of the source is expressed by locating many dipoles in a region. Assuming that the dipoles each have a time-varying moment, spatio-temporal patterns of magnetoencephalograms (MEGs) are simulated. The results show that the waveforms of MEG are affected significantly by varying the spread of the source.< >
The authors propose models in which both magnetoencephalogram (MEG) and electroencephalogram (EEG) activities evoked by color imagination are recorded simultaneously. The components of the magnetic fields perpendicula...
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The authors propose models in which both magnetoencephalogram (MEG) and electroencephalogram (EEG) activities evoked by color imagination are recorded simultaneously. The components of the magnetic fields perpendicular to the surface of a head were measured by using a DC SQUID with a first-derivative gradiometer. The authors observed that both MEG and EEG activities were affected by color imagination. The power spectrum of the MEG evoked by color imagination showed a single sharp peak at 11 Hz. In contrast, the power spectrum of EEG showed broad patterns. The EEG topography showed that the spectrum component at 11 Hz dominated in the occipital region. On the basis of these results, the authors propose a two-dipole model whose directions vary with time to explain the change in EEG topography evoked by color imagination.< >
A combination of magnetoencephalography (MEG) and MRI was used to localize the sources of human middle latency auditory evoked responses (MLR). MEG measurements were performed over the right hemisphere of five normal ...
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A combination of magnetoencephalography (MEG) and MRI was used to localize the sources of human middle latency auditory evoked responses (MLR). MEG measurements were performed over the right hemisphere of five normal volunteers while the left ear was stimulated by clicks. The MEG data were plotted onto the individual MR images. The sources of Pa, Nb, and Pb responses, which are the main components of MLR, were estimated to be in the auditory cortex. The source of Nb was found to be lateral to the source of Pa. In addition, the source of Pb was estimated to be anterior and lateral to the source of Pa.< >
The authors investigated the effects of the stimulation side on middle latency auditory evoked responses (MLR) with neuromagnetic methods. Middle latency auditory evoked magnetic fields elicited by 1.0 msec clicks del...
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The authors investigated the effects of the stimulation side on middle latency auditory evoked responses (MLR) with neuromagnetic methods. Middle latency auditory evoked magnetic fields elicited by 1.0 msec clicks delivered to the ipsilateral and contralateral ear were recorded with a 7-channel DC SQUID. The amplitudes and latencies of the magnetic equivalents of Pa and Pb responses, which are the two main peaks of MLR, were measured. The amplitude of the contralateral Pa response was found to be significantly larger than the ipsilateral Pa response. On the other hand, no significant difference was observed in the latencies of Pa and Pb between the ipsi- and contralateral responses.< >
This study focuses on the detection of ABR magnetic fields using a SQUID magnetometer with a variable baseline. The authors developed a highly sensitive DC-SQUID system. The SQUID magnetometer has a first-order gradio...
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This study focuses on the detection of ABR magnetic fields using a SQUID magnetometer with a variable baseline. The authors developed a highly sensitive DC-SQUID system. The SQUID magnetometer has a first-order gradiometer with a variable baseline, i.e., the distance between two co-axial coils. ABR signals, which are generated from a brainstem in a deep part of the brain, are very weak fields. The authors measured the ABR magnetic fields using three gradiometers which have different baselines: 30 mm, 50 mm and 80 mm. In this experiment, the authors were able to obtain the best signal-to-noise ratio using the gradiometer with the 50 mm baseline.< >
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