The Delayed Ack Method to Measure Trust in Organic Computing Systems

Trust is an important factor for autonomous distributed systems. Organic Computing systems feature self-organizing techniques to manage complex distributed systems. This paper introduces the delayed ack method to measure and calculate trust values of network entities based on direct observation. It is designed to do this with minimum overhead. We demonstrate the approach within our middleware OCμ and show that the algorithm converges towards the real trust value. Evaluations also show the amount of measurements needed to gain a meaningful trust value as well as the influence of a node´s own reliability on trust computation. To our knowledge this is the first published method that proposes how to gather trust by direct observation.