Minimising tardiness in hybrid two-stage batch scheduling problem in cyber-physical systems

The real time characteristic is a critical property of cyber-physical systems and the transmission tardiness introduced by the computer system can lead to a significant performance degradation. In order to improve the real-time performance, data aggregation is always employed during data transmission. This paper studies a hybrid two-stage batch scheduling problem in which a set of receiving sensors are assigned to collect the data at the first stage and an aggregation sensor is employed to receive the data from receiving sensors, fuse and transmit the data to the destination at the second stage. Two objectives, which are minimising the number of tardy tasks and the total transmission tardiness, are studied. Some analytical properties are proved and some algorithms are proposed to solve the problem. Extensive numerical experiments are conducted to test the performances of the proposed algorithms.