Economics Insights @ CBS

Often the timing of certain activities has a strong periodic element. Due to circumstances an activity is sometimes made outside the regular cycle, but it does not break the cycle. Thus, the timing of future activities is highly predictable. We provide a stochastic model where the data are not seasonal yet the optimal behaviour has a strong periodic element.

Radial patterns of optical flow produced by observer translation could be used to perceive the direction of self-movement during locomotion, and a number of formal analyses of such patterns have recently appeared. However, there is comparatively little empirical research on the perception of heading from optical flow, and what data there are indicate surprisingly poor performance, with heading errors on the order of 5 degrees–10 degrees.

We consider the polymatroidal flow network model which incorporates two important extensions of the standard maximal flow problem: general concave objective functions of the vector of supplies to a collection of sinks, as well as polymatroidal capacity restrictions on sets of arcs emanating from or pointing to a common node. A number of important applications are reviewed.

We present an exact solution method for a single-server queueing system which alternates between periods in which service can be provided (on-periods) and periods in which the server is out of operation (off-periods). The arrival process is Poisson, on-periods are assumed to have a phase-type distribution, and service times and off-periods are assumed to be arbitrary.