a b s t r a c tThis study presents an evaluation of an advanced Doppler radar-based method for detection of vital signs, presence, and activity of a human subject in a test room with radar-signal reflecting aluminum-coated surfaces. Ten test subjects lay in four positions, and they sat in two locations in the room, both breathing normally and holding their breath. The mean ratios of the pulse rates determined from the radar signal and electrocardiography and respiration reference signals were 110% (respiration) and 99% (heartbeat), and the mean occupied and empty room radar signal variance ratios were 608 (breathing) and 20 (breath-hold). In a one-subject activity monitoring test, walking, standing and lying activities could be well separated from the radar signal. The results are promising and the proposed system seems to have potential to be used in position-independent health and activity monitoring of, for example, elderly people in care homes or intoxicated people in police custody.

No abstract

No abstract

A pulsed NMR system for platinum nuclear spin thermometry and for measurements of the nuclear spin-lattice relaxation time T, has been developed. The nuclear free precession signal is detected with a fast linear det~ctor an~ an RC integrator. The T, measurements were performed by the transient recovery ~ethod with the aid of automated circuitry multiplexing of the linear detector output into four separate m~eg~ators. The ~hermometer was tested between 10 mK and 2 K using a powdered platinum sample. Wlthm the expenm~ntal accuracy of about 2% the amplitude of the nuclear free precession signal was foun? to be propor~\Onal to 11 T. The thermometer could be calibrated with the aid of the Korringa relation T, T=K, With K=29.6 msec K. Thermal equilibrium problems of the T measurements are discussed in detail. I II. THERMOMETER ELECTRONICSThe basic arrangement of our thermometer circuitry! is similar to that described by Wahlstedt et al. 2 The block diagram of the thermometer electronics is shown in Fig. 1.

No abstract

No abstract