T. Tietz, J. Waitelonis, K. Zhou, P. Felgentreff, N. Meyer, A. Weber, and H. Sack. Proceedings of the Posters and Demo Track of the 15th International Conference on Semantic Systems co-located with 15th International Conference on Semantic Systems (SEMANTiCS 2019), Karlsruhe, Germany, September 9th - to - 12th, 2019, volume 2451 of CEUR Workshop Proceedings, CEUR-WS.org, (2019)