Resumen
The problem of assigning information packets of different services to time slots of a radio frame is addressed. Packet sizes are divisible, and a maximum time slot to which a packet can be assigned is given. We present a polynomial-time scheduling algorithm maximizing the number of scheduled packets.

Resumen
We derive several results on the computational complexity of train rearrangement problems in railway optimization. Our main result states that arranging a departing train in a depot is NP-complete, even if each track in the depot contains only two cars.