Critical situation management utilizing IoT-based data resources through dynamic contextual role modeling and activation

New opportunities have been created for the management of critical situations utilizing the Internet of Things (IoT). However, one of the difficulties in providing services for critical situation management using IoT is that access will often be needed by users at the critical events, where access to data and resources is usually restricted by means of their normal roles. In Role-Based Access Control, these roles are organized in static hierarchies and users are authorized to play such roles in order to exercise their organizational functions. However, some of these roles cannot be organized in the same way in static hierarchies as the authorizations granted to such roles directly correspond to the dynamic contextual conditions (e.g., body sensors data). Users need to satisfy these conditions to exercise the functions of such dynamic contextual roles. These dynamic conditions can be effectively derived from the IoT devices in order to manage the critical situations. However, a large number of static roles and contextual conditions has led to the high administrative and processing overheads. In this paper, we present a formal approach to CAAC for dynamically specifying the contextual roles based on the relevant contextual conditions derived from information provided through IoT. We also introduce an ontology-based approach which models the dynamic contextual roles and its associated access control policies. We demonstrate the feasibility of our proposal by providing a walkthrough of the whole mechanism. We also carry out an experimental study on the performance of our approach compared to our previous approach.