Mycoplasmal mastitis in dairy herds

This paper addresses two main issues of the DOK system [15], that is the design of a framework for enforcing security policies and a secure architecture which implements such a framework. Federated security policies are expressed as logic-based expressions (called "aggregation constraints") specifying the different combinations of transactions that a user is not allowed to issue, either in single or multiple states of a federation. To enable efficient monitoring of aggregation constraints, state transition graphs are generated to model the different sub-computations of the constraints. Two marking techniques, namely LMT (Linear Marking Technique) and ZMT (Zigzag Marking Technique), are proposed to detect violations of federated security policies. To enable an effective enforcement of security policies, we designed a secure DOK architecture using specialised agents: (i) coordination agents allow the coordination of different federated activities, (ii) task agents perform specific tasks of th..