On general systems with randomly occurring incomplete information

In the system and control community, the incomplete information is generally regarded as the results of (1) our limited knowledge in modelling real-world systems; and (2) the physical constraints on the devices for collecting, transmitting, storing and processing information. In terms of system modelling, the incomplete information typically includes the parameter uncertainties and norm-bounded non-linearities that occur with certain bounds. As for the physical constraints, two well-known examples are the actuator/sensor saturation caused by the limited power/altitude of the devices as well as the signal quantization caused by limited bandwidth for signal propagation. Traditionally, the incomplete information is assumed to occur in a deterministic way, that is, it always happens in a certain environment. Such an assumption is, however, not always true. Recently, in response to the development of network technologies, the incomplete information often appears in a random fashion depending on the random fluctuation of the network loads/conditions whose probabilistic distribution could be estimated a priori through statistical tests. Two intensively studied examples are the packet dropouts and communication delays. So far, the phenomenon of randomly occurring incomplete information (ROII) has become more and more prevalent in networked environments, and a great deal of research attention has devoted to the investigation on the ROII including randomly varying non-linearities, randomly occurring mixed time delays, randomly occurring parameter uncertainties and randomly occurring quantization errors, to name just a few. ROII, if not properly handled, would seriously deteriorate the performance of a control system. It is, therefore, the purpose of this special issue to examine (1) how ROII impacts on the system behaviour and (2) how to analyse/control systems with ROII.