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This research proposes a PVDF film pulse wave sensor for use in driver's drowsiness detection. The sensor non-intrusively measures heart pulse wave from driver's palm and an adaptive filter is employed to cancel the measurement noise aroused by the changing of gripping force. Experimental results show clear pulse wave signals can be obtained. Two-hour driving simulation is performed for drowsiness detection tests. The low frequency to high frequency (LF/HF ratio) is calculated from power spectrum density (PSD) of subjects' heart rate time series. The LF/HF ratio shows decreasing trends as subjects go from awake to drowsy.

A reference setup for system calibration of industrial transformer loss measurement (TLM) systems consists of three main components, a voltage divider, current transformer and a power meter, and their phase displacements should each not be more than 10 µrad to achieve an overall system uncertainty of better than 20 µW/VA. We have extensively verified the uncertainty level of the current-comparator-based capacitive voltage divider (CVD) used in the TLM reference setup of the Van Swinden Laboratorium (VSL), both from the component level and the system as a whole. Different practical conditions relevant for on-site measurements are considered, e.g. measurement cable lengths, cable types and grounding. The verification measurement results show an agreement of better than (6 ± 6) × 10 −6 in ratio error and (4 ± 6) µrad in phase displacement between the CVD component and system calibrations up to 100 kV. Requirements for achieving this agreement are adequate grounding of the CVD and the use of triax cable between the HV capacitor and the CVD low-voltage electronics in case large distances have to be covered on-site. The (4 ± 6) µrad agreement in phase displacement is well within the required 10 µrad limit for voltage measurements as part of on-site TLM system calibrations with 20 µW/VA overall uncertainty at low power factors.

there are many plates and beams on the radar array. In the process of finite element calculation, choosing the appropriate shell mesh finite element model to replace the solid finite element model can reduce the calculation amount. In this paper, the finite element solid mesh model is established based on the reflection panel model of a radar antenna array, and the simulation results are obtained. Secondly, the shell grid is used to perform finite element modeling and correction calculations on the reflective panel. The results show that the modified shell grid calculation results are very close to the solid grid model results, and can replace the solid grid to simplify the calculation of the array.

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