POSTURAL STABILITY AND ANTICIPATORY POSTURAL ADJUSTMENTS PERFORMANCES AFTER GENERAL MUSCLE FATIGUE IN TRAINED AND UNTRAINED ADULTS

The objective of this study was to explore the differences of postural stability and Anticipatory Postural Adjustments (APAs) performances after general muscle fatigue between trained and untrained adults. The displacements of Center of Pressure (COP) during static bipedal standing, the APAs of deep trunk muscles induced by voluntary movements, the Heart Rate (HR) and the Borg Rating of Perceived Exertion Scale (RPE) were recorded before and after a 20-minute general muscle fatigue on a rowing ergometer for eighteen trained and eighteen untrained subjects. After fatigue, the trained group exhibited less disturbed postural stability performances. Meanwhile, earlier and larger APAs activations of lumbar multifidus (LMF) were found in trained group regardless of fatigue conditions. These results suggest a beneficial effect of long-term training experience on counter-perturbation feedforward control and highlight the distinguishing role of LMF in evaluation and rehabilitation of motor dysfunction

Free dcpo-algebras via directed spaces

Directed spaces are natural topological extensions of dcpos in domain theory and form a cartesian closed category. We will show that the D-completion of free algebras over a Scott space $\Sigma L$, on the context of directed spaces, are exactly the free dcpo-algebras over dcpo $L$, which reveals the close connection between directed powerspaces and powerdomains. By this result, we provide a topological representation of upper, lower and convex powerdomains of dcpos uniformly.Comment: 18 page

Event-based multi-objective filtering for multi-rate time-varying systems with random sensor saturation

summary:This paper focuses on the multi-objective filtering of multirate time-varying systems with random sensor saturations, where both the variance-constrained index and the $H_\infty$ index are employed to evaluate the filtering performance. According to address issues, the high-frequency period of the internal state of the system is nondestructively converted to the low-frequency period, which determined by the measurement devices. Then the saturated output of multiple sensors is modeled as a sector bounded nonlinearity. At the same time, in order to reduce the communication frequency between sensors and filters, a communication scheduling rule is designed by the utilization of an event-triggered mechanism. By means of random analysis technology, the sufficient conditions are given to guarantee the preset $H_\infty$ performance and variance constraint performance indexes of the system, and then the solution of the desired filter is obtained by using linear matrix inequalities. Finally, the validity and effectiveness of the proposed filter scheme are verified by numerical simulation