[ACM Press the 2019 ACM International Joint Conference on Pervasive and Ubiquitous Computing and the 2019 ACM International Symposium - London, United Kingdom (2019.09.09-2019.09.13)] Proceedings of the 2019 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2019 ACM International Symposium on Wearable Computers - UbiComp/ISWC '19 - A theoretical framework to study long-term use of smart eyewear