Results on multi-day simulated data show circadian energy variations in healthy subjects and non-circadian fluctuations throughout 24 h periods in patient models suffering from hypercortisolism. We derive Bayesian filter equations for state estimation and use the Expectation-Maximization algorithm for model parameter recovery. We relate an internal energy state variable to cortisol pulse timings and to the upper and lower serum cortisol envelopes. Secretory event timings carry important information regarding internal feedback signaling taking place, as do the upper and lower serum cortisol levels. Cortisol is secreted in pulses and follows a 24 h circadian rhythm. We develop a state-space model relating the body's internal energy to cortisol hormone secretions. Keywords: Kalman filtering, Parametric filtering and estimation, Physiological systems modeling - Signal processing in simulationДЄbstract: Hormones play a fundamental role in homeostasis. These results provide some keys to interpret knowingly ActiLife count based studies.ДЄ Cortisol-Based Energy Decoder for Investigation of Fatigue in Hypercortisolism This study reproduces well ActiLife filter and reveals the impact of band-pass filtering on ActiLife count conversion. plateau-phenomenon) thanks to a treadmill test with incremental speed (n=4). Experimental data were used 1) to assess reconstructed filter performances to replicate ActiGraph counts during an urban-circuit involving 20 subjects wearing an ActiGraph GT3X+ and 2) explain filter limitations (e.g. Several points are discussed regarding bandpass filtering and amplitude non-linearities that may hamper some analysis. This paper investigates the way how Actigraph counts are computed. The accelerometer data are usually converted into activity counts and these counts can be used on their own to quantify the intensity and duration of a PA period or they can serve as features for energy expenditure computation or activity classification. Keywords: Adaptive filtering, Time-frequency and time-scale analysis - Empirical mode decomposition in biosignal analysisДЄbstract: Objective physical activity (PA) quantification is traditionally achieved using lightweight accelerometers accounting for activity frequency, intensity and duration. Physical Activity Estimation from AccelerometryД¬RNH RhГґne-Alpes/CENS, Centre Hospitalier Lyon Sud - 165 Chemin Multi-reference implementation reveals its superiority, whereas the single-reference implementation suffers from the electrodes positioning and cannot be trustily used even for the fetal heart rate only on the adopted dataset. The performance is assessed on real data in terms of signal-to-interference ratio, detection of fetal QRS complexes and maternal ECG attenuation. In this work, this aspect is systematically analyzed by comparing single- and multi-reference implementations of the QRD-RLS adaptive filter, and by challenging them in the fetal ECG enhancement on three abdominal leads differently oriented in space. Such techniques encompass approaches using one or more reference signals, which is an important aspect for the development of accurate and unobtrusive monitoring systems. Among the different techniques proposed in the scientific literature, some variants of adaptive filters have been proposed for maternal ECG cancellation and fetal QRS complex enhancement. However, the signal-to-noise ratio is significantly low, since fetal ECG is embedded in instrumental noise and spectrally overlapping maternal electrophysiological interferences. Abstract: Non-invasive fetal electrocardiography (ECG) would allow accessing very relevant information on fetal cardiac function, especially for arrhythmias.

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