The 2 full-time PhD positions will be part of an ITEA project entitled MAST - Managing Sustainability Tradeoffs. The group at the University of Groningen has teamed up with a European consortium to strengthen the way in which sustainability can be brought to products and services in a technically viable way. The aim of the project is to deal with the complex trade-offs between two aspects of sustainability: technical sustainability (esp. technical debt) and environmental sustainability (esp. carbon footprint).