Adapting and Evaluating Distributed Real-Time and Embedded Systems in Dynamic Environments
QoS-enabled pub/sub middleware, such as the OMG Data Distribution Service (DDS) or the JAIN Service Logic Execution Environment (SLEE), is increasingly used in mission-critical Distributed Real-time and Embedded (DRE) application domains ranging from shipboard computing environments to air traffic management systems, telecom and fractionated spacecraft constellations. Various mechanisms in the middleware, such as transport protocols, can be used to support QoS and provide desired behavior. It can be hard, however, to quantitatively evaluate multiple QoS concerns that interrelate with each other. For example, data reliability and jitter can be at odds since reliability often implies retransmission of data which can add to jitter.