In this note we propose a controller that solves the problem of coordination of two (or more) robots, under a master-slave scheme, in the case when only position measurements are available. The controller consists of a feedback control law, and two nonlinear observers. It is shown that the controller yields ultimate uniformly boundedness of the closed loop errors, and a relation between this bo...

We present a new, simple algorithmic idea for exploiting the potential for bidirectional communication present in many modern interconnects for the collective MPI operations broadcast, reduction and scan. Our algorithms achieve up to twice the bandwidth of most previous and commonly used algorithms. In particular, our algorithms for reduction and scan are the currently best known. Experiments o...

It is basically a solved problem for a server to authenticate itself to a client using standard methods of Public Key cryptography. The Public Key Infrastructure (PKI) supports the SSL protocol which in turn enables this functionality. The single-point-of-failure in PKI, and hence the focus of attacks, is the Certi cation Authority. However this entity is commonly o -line, well defended, and no...