Positive Dynamical Systems: New Applications, Old Problems

This review paper presents four relevant and very recent real-world application problems demanding developments of long-standing theoretical open problems in the field of positive systems research. Notably, the selected applications belong to very different fields of science and technology, ranging from biology and medicine to civil and electronic engineering. This clearly shows how pervasive positive systems are in mainstream research. Additionally, the theoretical issues stemming from these applications are the living proofs of how the apparently simple positivity constraint on the variables of interest makes the theory behind practical problems far from trivial, even for the linear case.