Recent Posts by Roman Stumm

DelyMate – communication using Spring, RabbitMQ and JSON

The Viaboxx DelyMate product consists of separate subsystems that need a communication infrastructure to exchange messages. The DelyMate client is a Java/Groovy-program running on the delivery machine to open the lockers and to handle the interaction with the user at the machine, e.g. to process input from the touch screen. The DelyMate server is a…
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Distances for Vehicle Routing with GraphHopper

This articles gives some hints for solving the Vehicle Routing with GraphHopper and OptaPlanner. It focuses on the GraphHopper's API to compute distances. I also recommend the blog post of Geoffrey De Smet about OptaPlanner and GraphHopper, that discusses the necessity of using real distances instead of euclidian distances for solving real vehicle routing problems.…
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Generate nice documents out of Confluence

Problem: Your company is using Confluence and this is the place, where the employees write their documents, maintain the links between the pages etc. You have to deliver high-quality documents (documentation, manuals etc.) to your customer, so you have to produce PDF or Word-files. The customer wants you to use specific templates with header-page, logo,…
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Scaling the Vehicle Routing Problem

This article gives an idea how the vehicle routing problem can scale for many vehicles and many stops. During solving of a problem, OptaPlanner tries to find better and better solutions by creating (random) moves to exchange the sequence of the locations in the vehicle routes. One of the major bottlenecks is the calculation of…
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