A real-time task model based on ideal instant

In many digital control applications, data acquisition are process control are time-critical actions, assumed to be instantaneous and strictly periodic. However aspects related to real-time scheduling algorithms may, postpone the task execution and, consequently. delay the data acquisition and process control. We consider the acquired data from sensors as valid if acquired inside a timeinterval that surrounds an ideal instant which is the point of maximum systems benefit. Pie data acquired before or after this time-interval are considered useless to the controller. We propose a new task model to deal with the variation in the evecution time of a specific point inside tasks. In this model, tasks have an ideal instant to present their results or acquire data from sensors (QoS metric).