Production planning (RCPSP)

Production planning of product batches is a combination of batch set assignment and plant scheduling. We can solve this problem with various algorithms including MILP, constraint programming (CP) and heuristics. We have implemented and evaluated different model variants for the assignment part. While portfolio-based solvers are promising (OR-Tools CP-SAT, Chuffed), their solving time is complex and depends on many different factors.

Weather NRW 2009-2018 Visualization (Plotly Dash, served by Gunicorn)

What is the station of highest summer temperature in North-Rhine Westfalia in the years 2009-2018 (named after its city location)?

This and other questions you can answer with weather observation data and interactive visual analytics. The dataset is open data from the german weather service, described here (en / de). It has been prepared and joined as in our notebook.

Compression Domain Queries

The compression/decompression of digital elevation models is necessary for handling large areas in high resolutions. We propose a wavelet-based datastructure for the on-the-fly decompression during ray and general visibility queries.

Geometric Constraints & Constraint Solving

Using linear program relaxation, it is possible to compute solution bounds for polynomial (in-)equalities. The approach is iterative and complete in terms of solutions. The Bernstein-Bézier form can be used to form a tight convex enclosure of the polynomial variety. The number and the computational complexity for finding its coefficients (from the given monomial coefficients) are essential for this method. Bernstein-Bézier techniques and interval arithmetic are essential tools inside.