A genetic algorithm-based procedure for solving the optimal phasor measurement units (PMUs) placement problem is presented. It determines the minimal number of PMUs and their geographic distribution making the network observable, and it shows the relationship between the number of current phasors that must be measured on each PMU and the necessary number of PMUs for a given network.

Autonomous robots are capable of navigating on their own. Shared control approaches, however, allow humans to make some navigation decisions. This is typically executed either by overriding the human or the robot control at some specific situations. In this paper, we propose a method to allow cooperation between humans and robots at each point of any given trajectory so that both have some weight in the emergent behavior of the mobile robot. This is achieved by evaluating their efficiencies at each time instant and combining their commands into a single order. In order to achieve a seamless combination, this procedure is integrated into a bottom-up architecture via a reactive layer. We have tested the proposed method using a real robot and several volunteers, and results have been satisfactory both from a quantitative and qualitative point of view.