The proportional Service model is receiving a lot of attention as an attractive model for providing differentiated services on the Internet. In particular, this model is controllable, able to provide the “tuning knobs” for network operators to quantitatively differentiate the quality-ofservice (QoS) of different classes, and lends itself naturally to simple pricing schemes. In this paper, we fo...

In this paper we prove that the broad class of direct-search methods of directional type, based on imposing sufficient decrease to accept new iterates, exhibits the same worst case complexity bound and global rate of the gradient method for the unconstrained minimization of a convex and smooth function. More precisely, it will be shown that the number of iterations needed to reduce the norm of ...

This paper describes a new measure for presence in immersive virtual environments (VEs) based on data that can be obtained unobtrusively during the course of a VE experience. At different times during an experience a participant will occasionally switch between interpreting the totality of sensory inputs as forming the VE or the real world. The number of transitions from virtual to real is coun...