104,884 research outputs found
Realization of Systems with Exogenous Inputs and Subspace Identification Methods
No full textThis paper solves the stochastic realization problem for a discrete-time stationary process with an exogenous input. The oblique projection of the future outputs on the space of the past observations along the space of the future inputs is factorized as a product of the extended observability matrix and the state vector. The state vector is chosen by using the canonical correlation analysis (CCA) of past and future conditioned on the future inputs. We then derive the state equations of the optimal predictor of the future outputs in terms of the state vector and the future inputs. These equations lead to a forward innovation model for the output process in the presence of exogenous inputs. The basic step of the realization procedure is a factorization of the conditional covariance matrix of future outputs and past data given future inputs. This factorization is based on CCA and can be easily adapted to finite input–output data. We derive four stochastic subspace identification algorithms which adapt the realization procedure to finite input–output data. Numerical results are also included
[Acute schistosomiasis (Katayama fever)]
No full textAcute schistosomiasis (Katayama fever) may present with a broad spectrum of symptoms three to six weeks after primary infection by Schistosoma (S) mansoni, S. japonicum or, more rarely, S. haematobium. The acute phase of schistosomiasis is frequently confused with other feverish diseases. It occurs almost exclusively in nonimmune visitors to endemic areas. We describe seven cases of acute S. mansoni infection. The pathogenesis, clinical features, diagnosis and treatment are briefly discussed. Katayama fever should be considered in patients returning from endemic areas with fever and eosinophilia. Clinically normal, but potentially exposed travel companions should be examined as well. Early diagnosis and treatment may be important in preventing the infection's serious sequelae of the infection
Subspace identification of closed-loop systems by orthogonal decomposition
No full textIn this paper, we consider a problem of identifying the deterministic part of a closed loop system by applying the stochastic realization technique of (Signal Process. 52 (2) (1996) 145) in the framework of the joint input-output approach. Using a preliminary orthogonal decomposition, the problem is reduced to that of identifying the plant and controller based on the deterministic component of the joint input-output process. We discuss the role of input signals in closed loop identification and the realization method based on a finite data, and then sketch a subspace method for identifying state space models of the plant and controller. Since the obtained models are of higher order, a model reduction procedure should be applied for deriving lower order models. Some numerical results are included to show the applicability of the present technique
A Subspace Identification of the deterministic part of a state-space model operating in closed loop
No full text
Somatosensory evoked potentials and high frequency oscillations are differently modulated by theta burst stimulation over primary somatosensory cortex in humans
No full textObjective: The effects of theta burst stimulation (TBS) have been extensively investigated in primary motor cortex, where it leads to long-lasting LTP/LTD-like effects on synaptic plasticity. This study aimed to extend these observations to sensory cortex. Methods: Fourteen healthy subjects participated in the study. Conditioning 600-pulse intermittent TBS (iTBS) and continuous TBS (cTBS) were delivered to left somatosensory cortex (S1) with an intensity of 80% active motor threshold. Somatosensory evoked potentials (SEPs) were evoked by median nerve electrical stimulation at right wrist. High frequency oscillations (HFOs) were obtained by digital filtering of original SEPs and divided into early and late subcomponents, relative to N20(peak) latency. Results: Repeated-measures ANOVA showed that iTBS facilitated N20(onset)-N20(peak) at 15 min and N20(peak)-P25 at 15 and 30 min after conditioning, whereas cTBS did not. iTBS left the early and late HFOs unchanged. Conversely, cTBS facilitated the early HFOs, whereas it inhibited the late HFOs at 15 min after conditioning. Conclusions: S1-iTBS facilitated SEPs without changes in HFOs whereas cTBS modulated early and late HFOs without changes in SEPs. Significance: S1-TBS produces lasting changes in the excitability of intracortical circuits generating SEPs and HFOs differentially through mechanisms of LTP/LTD-like synaptic plasticity. (C) 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
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