Category Archives: Production Operations

New Paper in Games

I recently published a new paper in the journal Games.  You can see it below.

It deals with a very important logistics problem. In a cold chain, different parcels require different conditions of temperature. A multiple compartment vehicle can be sued to consolidate loads with different temperature characteristics in one vehicle.   But loading the vehicle at a low cost is a hard problem, requiring heuristics to solve.  And even then, how do we divide the cost of loading among the different package owners in a fair way?  ‘Fair’ here means that no group of owners will choose to leave the consolidation, because they cannot do better on their own than the cost they are charged.

The paper uses an inductive algorithm on top of a common heuristic to give a method for solution. There is a small example in the paper that shows how to apply the algorithm.

games-logovia Games | Free Full-Text | Sharing Loading Costs for Multi Compartment Vehicles

You can get the pdf here.  games-09-00025 (1) final version

 

Geographic gaps are widening in U.S. as economic growth increases

This is a quite interesting article on the distribution of economic development in the US.  It says we have to start doing something about the ill distribution to a few highly urbanized areas that are often based on high tech industries.

screenshot-www.brookings.edu 2018-01-25 13-18-03-392   via Geographic gaps are widening while U.S. economic growth increases

IATA to review air cargo load factor calculations

Project Selfie examined load factors used in reporting by major airlines. It turns out that there is a wide range of ways the load factor is calculated by airlines. Weight alone yields low load factors (the percent of utilization of the aircraft with respect to cargo weight).  Most of the airlines use a combination of weight and size, and this is done differently for different carriers.  Thus they report load factors on different bases, so they are not comparable.   IATA, the industry group, wants to have a more consistent basis than weight for reporting its figures for the industry. Weight alone is not very significant.

“(Weight alone) poorly reflects how full the planes really are.”

In short they cube out before they weigh out.  Packages that go by air are not very dense! This may partially explain why air freight rates are going up while load factors are not very high. So IATA has been misrepresenting capacity utilization of planes.

logo2via IATA to review air cargo load factor calculations after Project Selfie revelations – The Loadstar

Some notes on Project selfie:  Weight loadfactors a poor way of showing utilisation, Project Selfie confirms – The Loadstar