Cognitive radio (CR) is an enabling technology that helps efficiently use spectrum. In this paper, a collaborative spectrum sensing mechanism is proposed which combines passive detection and sensing service compensation. Theoretical analysis and simulations show that this method not only reduces the energy cost and the passive sensing time, but also maintains fairness in the CR communication sy...

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics...

This article compares two hypotheses regarding the mechanisms responsible for aging in humans and other mammals. In the passive mechanism, aging is the result of inadequacies in maintenance and repair functions that act to prevent or repair damage from fundamental deteriorative processes. In the active mechanism, a life span management system purposely limits life span by deactivating maintenan...