The optimization of the embedded software, the communication
and time-synchronization protocols, and the low energy
consumption of the devices has been carried out. A wearable
sensor system for reading Braille uses a compact tactile sensor
system, made up of a polyvinylidene fluoride (PVDF) film
for the sensory receptor [47]. The sensor is mounted onto a
fingertip and moved over Braille manually to obtain the output.
A robust recognition system has been developed to analyze
the waveforms of the signals obtained from the movements of
the fingers. A new scheme to identify the locations of wearable
sensor nodes in a wireless body area network (WBAN)
automatically has been presented [48] enabling unassisted
sensor nodes continuously monitor node locations without
anchor nodes or beacons. The authors have experimentally
demonstrated an enhancement of the scheme aiming to reduce
false-positive (Type I) errors in conventional accelerometerbased
on-body fall detection schemes. The authors have
explored on-body energy management mechanisms in the
context of emerging wireless body area networks [49]. It characterizes
the dynamic nature of on body links with varying
body postures which helps in developing a WBAN-specific
dynamic power control mechanism for optimal power assignments.
A multi-layer task model based on the concept of
Virtual Sensors to improve architecture modularity and design