6 research outputs found
On a universal photonic tunnelling time
We consider photonic tunnelling through evanescent regions and obtain general
analytic expressions for the transit (phase) time (in the opaque barrier
limit) in order to study the recently proposed ``universality'' property
according to which is given by the reciprocal of the photon frequency.
We consider different physical phenomena (corresponding to performed
experiments) and show that such a property is only an approximation. In
particular we find that the ``correction'' factor is a constant term for total
internal reflection and quarter-wave photonic bandgap, while it is
frequency-dependent in the case of undersized waveguide and distributed Bragg
reflector. The comparison of our predictions with the experimental results
shows quite a good agreement with observations and reveals the range of
applicability of the approximated ``universality'' property.Comment: RevTeX, 8 pages, 4 figures, 1 table; subsection added with a new
experiment analyzed, some other minor change
The Airline Container Loading Problem with Pickup and Delivery
This paper considers the loading optimization problem for a set of containers and pallets
transported into a cargo aircraft that serves multiple airports. Because of pickup and
delivery operations that occur at intermediate airports, this problem is simultaneously a
Weight & Balance Problem and a Sequencing Problem. Our objective is to minimize fuel
and handling operation costs. This problem is shown to be NP-hard. We resort to a
mixed integer linear program. Based on real-world data from a professional partner (TNT
Airways), we perform numerical experiments using a standard B&C library. This approach
yields better solutions than traditional manual planning, which results in substantial cost
savings.Optimization in air transpor