ABSTRACT
The complexity and high performance requirements of present-day industrial processes place increasing demands on control technology. The orthodox concept of driving a large systemby a central computer has become unattractive for either economic or reliability reasons. New emerging notions are subsystems, interconnections, distributed computing, parallel processing, and information constraints, to mention a few. In complex systems, where databases are developed around the plants with distributed sources of data, a need for fast control action in response to local inputs and perturbations dictates the use of distributed (that is, decentralized) information and control structures.
