Towards Systematic Specification of NonFunctional Requirements for Sharing Economy Systems Sharing Economy (SE) systems use technologies to enable sharing of physical assets and services among individuals. This allows optimisation of resources, thus contributing to the reuse principle of Circular Economy. In this paper, we assess existing SE services and identify their challenges in areas that are not technically connected to their core functionality but are essential in creating trust: information security and privacy, personal data protection and fair economic incentives. Existing frameworks for elicitation of nonfunctional requirements are heterogeneous in their focus and domain specific. Hence, we propose to develop a holistic methodology for nonfunctional requirements specification for SE systems following a topdowntop approach. A holistic methodology considering nonfunctional requirements is essential and can assist in the analysis and design of SE systems in a systematic and unified way applied from the early stages of the system development.

Towards GDPR Compliant Software Design: A Formal Framework for Analyzing System Models Software systems nowadays store and process large amounts of personal data of individuals, rendering privacy protection a major issue of concern during their development. The EU General Data Protection Regulation addresses this issue with several provisions for protecting the personal data of individuals and makes it compulsory for companies and individuals to comply with the regulation. However, few methodologies have been considered to date to support GDPR compliance during system development. In this paper, we propose a processcalculus framework for formal modeling of software systems during the design phase, and validation of properties relating to the GDPR notion of Consent, the Right to Erasure, the Right to Access, and the Right to Rectification. Moreover, the framework enables the treatment of the notion of purpose through privacy policy satisfaction. Validation is performed with static analysis using type checking. Our work is the first step towards a framework that will implement PrivacybyDesign and GDPR compliance throughout the development cycle of a software system.