Starting with NetLogo version 5.1.0, the use of the Java applets is unfortunately deprecated, as explained here; we plan to move in the future to the NetLogo Web feature, to restart publishing these essays in an interactive way.
So currently nothing working on line, but it is possible to download the introduction to the ABMs for the Last Mile Problem simulation work and its .nlogo file and the related files for the genetic algorithm optimization (to download, it is better to right click).