This paper presents the NAct (Nutrition & Activity) Ontology, designed to drive personalised nutritional and physical activity recommendations and effectively support healthy living, through a reasoning-based AI decision support system. NAct coalesces nutritional, medical, behavioural and lifestyle indicators with potential dietary and physical activity directives. The paper presents the first version of the ontology, including its co-design and engineering methodology, along with usage examples in supporting healthy nutritional and physical activity choices. Lastly, the plan for future improvements and extensions is discussed.

The requirements for the efficient management of authorisations in web-based collaborative applications lead to new access control administration paradigms during run-time. The need for fine-grained and just-in-time access control can effectively be addressed by dynamic administration of authorisations, via either proper role or permission activation. In this paper, an authorisation architecture that is based on the Dynamically Administering Role-based Access Control (DARBAC) model, and provides access control and meta-access control capabilities, is presented. The paper describes the implementation of the components and the structure of the architecture within the .NET framework. The application of the implemented access control system is also demonstrated. Based on the results of this demonstration, a more detailed investigation of the benefits of the proposed approach, which are related to improvements in the administration of Role-based Access Control (RBAC) during run-time, is presented.