Biological networks are complex in the terms of physical and chemical events that underlie them. System analysis methods can highlight different states of biological networks and the biologically significant transitions can be described. In addition modeling also reveals functional similarities between properties of biological networks and other well understood engineering systems such as electrical and electronic circuits and neural networks. Based on such descriptions it is possible to regard biological networks as systems that decode complex inputs into combinatorial patterns of biological activity. My interests lie in applying principles of engineering to biological networks and systems.