On general systems with network-enhanced complexities

In recent years, the study of networked control systems has gradually become an active research area due to the advantages of using networked media in many aspects, such as the ease of maintenance and installation, the large flexibility and the low cost. It is well known that the devices in networks are mutually connected via communication cables that are of limited capacity. Therefore, some network-induced phenomena have inevitably emerged in the areas of signal processing and control engineering. These phenomena include, but are not limited to, network-induced communication delays, missing data, signal quantization, saturations and channel fading. It is of great importance to understand how these phenomena influence closed-loop stability and performance properties. It should be pointed out that what a network induces is much more than those phenomena already studied. Nowadays, large-scale general systems are usually subject to various sorts of complexities such as parameter uncertainties, time delays, missing measurements, sensor/actuator saturations, signal quantization, information compressing, signal encryptions and nonlinear disturbances. These kinds of complexities which exist in a non-networked environment are becoming even more severe (in terms of their degrees or intensities) with networked systems due mainly to the limited bandwidth and fluctuation of network load. In other words, these kinds of complexities have been greatly enhanced because of the usage of the communication networks. In this case, it would be interesting to examine (1) how the networks have substantial impacts on the complexity and (2) how to analyse/reduce such kind of networkenhanced complexity. Systems with network-enhanced complexities (NEC) have already become an ideal research area for control engineers, mathematicians and computer scientists to manage, analyse, interpret and synthesize functional information from real-world networked systems.