The information-carrying capacity of the d-dimensional depolarizing channel is computed. It is shown that this capacity can be achieved by encoding messages as products of pure states belonging to an orthonormal basis of the state space, and using measurements which are products of projections onto this same orthonormal basis. In other words, neither entangled signal states nor entangled measurements give any advantage for information capacity. The result follows from an additivity theorem for the product channel /spl Delta//spl ominus//spl Psi/, where /spl Delta/ is the depolarizing channel and /spl Psi/ is a completely arbitrary channel. We establish the Amosov-Holevo-Werner(see Probl. Inform. Transm., vol.36, p.305-313, 2000) p-norm conjecture for this product channel for all p/spl ges/1, and deduce from this the additivity of the minimal entropy and of the Holevo quantity /spl chi//sup */.

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This paper describes a control method for searching suitable gripping points on the outline of generic shapes. It is aimed at robotic grasping tasks where no full geometrical knowledge of the shape is assumed. We first describe the method for a range of 2D generic shapes and then instantiate the method for pick and place operations on known shapes. The algorithms are run on the shape as it appears on the computer screen directly from a vision system. Virtual robotic fingers and associated sensors are then configured and positioned on the screen with three variables being simultaneously controlled. When the control systems reach a steady state, information about virtual finger position and orientation are then used to drive the manipulator.