Sensors (Basel, Switzerland)
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Sensors integrated into objects of everyday life potentially allow unobtrusive health monitoring at home. However, since the coupling of sensors and subject is not as well-defined as compared to a clinical setting, the signal quality is much more variable and can be disturbed significantly by motion artifacts. One way of tackling this challenge is the combined evaluation of multiple channels via sensor fusion. ⋯ The shape-based signal-to-noise ratio SNR S is introduced and used to quantify the effect on motion on different sensing modalities. Based on this analysis, an optimal combination of sensors and fusion methodology is developed and evaluated. Using the proposed approach, beat-to-beat heart-rate is estimated with a coverage of 99.5% and a mean absolute error of 7.9 ms on 425 min of data from seven volunteers in a proof-of-concept measurement scenario.
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This paper reports a dual-butterfly structure gyroscope based on the traditional butterfly structure. This novel structure is composed of two butterfly structures, each of which contains a main vibrational beam, four proof masses, and a coupling mechanism. ⋯ The experimental results show a Q-factor of 10,967 in driving mode and there were two peaks in the frequency responses curve of sensing direction due to unavoidable fabrication errors. Scale factor and bias instability were also measured, reaching a scale factor of 10.9 mV/°/s and a bias instability of 10.7°/h, according to the Allan Variance curve.