The goal of this study was to examine the optimal strategies for the recognition of gait phase based on surface electromyogram (sEMG) of leg muscles while children with cerebral palsy (CP) walked on a treadmill. Ten children with CP were recruited to participate in this study. sEMG from eight leg muscles and leg position signals were recorded while subjects walked on a treadmill. The position signals of left and right legs were used to develop a five gait sub-phases classifier, i.e., mid stance, terminal stance, pre-swing, mid swing, and terminal swing. Seven feature sets of sEMG signals were tested in recognizing the five gait sub-phases of children with CP. Results from this study indicated that the recognition performance of mean absolute value and zero crossing was better than that with other feature sets when using support vector machine (average classification accuracy was 89.40%). Further, we found that the performance of gait phase recognition is relatively better in pre-swing than other sub-phases, and the performance of gait phase recognition is relatively poorer in mid-swing than other sub-phases. Results from this study may be used to develop an intention-driven robotic gait training system/paradigm for assisting walking in children with CP through robotic training.

Ambipolar field-effect transistors allowing both holes and electrons transport can work in different states, which are attractive for simplifying the device manufactures and miniaturizing the integrated circuits. However, conventional ambipolar transistors intrinsically suffer from poor switching-off capability because the gate electrode is not able to simultaneously deplete holes and electrons across the entire transport channel. Here, we show that the switching-off capability of polymer ambipolar transistor is largely improved by up to 3 orders, through introducing non-uniformly distributed compensation potentials along the channel to synchronically tune the charge transport at different channel locations. Non-uniformly gate-stressed conjugated-polymer@insulator blend film induces non-uniformly trapped charges in the insulators, which consequently generates non-uniform compensation electrical field imposed in the conjugated-polymers. Both n-type and p-type operations with high mobility (2.2 and 0.8 cm2s-1V-1 respectively) and high on/off ratio (105) are obtained in the same device, and the device states are reversibly switchable, which provides a new strategy for three-level non-volatile memories and artificial synapses.