Alfred Link

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The variability of electric and magnetic signals from the heart during the depolarization phase is investigated. A signal processing method is developed, which provides estimates for the beat-to-beat variability of the QRS-complex. The method is based on the decomposition of the depolarization signal into bandpass signals by means of the Morlet wavelet(More)
A semi-parametric approach for the quantitative analysis of magnetic resonance (MR) spectra is proposed and an uncertainty analysis is given. Single resonances are described by parametric models or by parametrized in vitro spectra and the baseline is determined nonparametrically by regularization. By viewing baseline estimation in a reproducing kernel(More)
− We consider the task of uncertainty evaluation in the context of dynamic measurements. We assume that the relation between the time-dependent value of the measurand and the available output signal of an employed sensor is governed by a linear time-invariant system. Estimation of the measurand is done by applying a digital filter to the sensor's output(More)
− The output signal of an accelerometer typically contains dynamic errors when a broadband acceleration is applied. In order to retrieve the applied acceleration, post-processing of the accelerometer's output signal is required. To this end, we propose the application of a digital filter. We describe the construction of an appropriate filter and consider(More)
DC-magnetoencephalography (DC-MEG) technique has been refined and allows to record cortical activity in the infraslow frequency range less than 0.1 Hz noninvasively. Important questions however, remained, especially, how specific these infraslow activations can be recorded and whether different activations, for example, motor versus acoustic, can be(More)
Pooling information from multiple, independent studies (meta-analysis) adds great value to medical research. Random effects models are widely used for this purpose. However, there are many different ways of estimating model parameters, and the choice of estimation procedure may be influential upon the conclusions of the meta-analysis. In this paper, we(More)
The compensation of LTI systems and the evaluation of the according uncertainty is of growing interest in metrology. Uncertainty evaluation in metrology ought to follow specific guidelines, and recently two corresponding uncertainty evaluation schemes have been proposed for FIR and IIR filtering. We employ these schemes to compare an FIR and an IIR approach(More)
− Knowledge of the transfer function of a force transducer is required in order to determine a transient force from the transducer's output signal. We describe a linear least-squares fit method for system identification to estimate the transfer function from sinusoidal force calibration measurements, and we consider the evaluation of uncertainty associated(More)
− We show that correlations in the estimate of the impulse response of ultrafast sampling oscilloscopes might play an important role for uncertainty evaluations. This is demonstrated by determining the uncertainty associated with the estimate of the oscilloscope's input signal which is calculated using the output signal of the oscilloscope and the impulse(More)
Appropriate spatial filtering followed by temporal filtering is well suited for the single-trial analysis of multi-channel magnetoencephalogram or electroencephalogram recordings. This is demonstrated by the results of a single-trial latency analysis obtained for auditory evoked M100 responses from nine subjects using two different stimulation frequencies.(More)