The Challenge of Complex Systems

  • A System is a set of interacting components--whether human-made, naturally-occuring, or a combination of both.
  • By "interact", we mean the exchange of physical force, energy, mass flow, or information, such that one component can change the state of another component.
  • The technologies or natures of these systems may be mechanical, chemical, electronic, biological, informational, or combinations of these or others.
  • The behavior of a system can include "emergent" aspects that are not a characteristic of any individual component, but arise from their combination.
  • Emergent properties can be valuable (e.g., delivery of new services) or undesired (e.g., dangerous or unstable).
  • The behavior of a system is often not easily predicted from the behavior of its individual components, and may also be more complex.
  • The complexity of human-engineered systems is growing, in response to demands for increased sophistication, in response to market or military competition, and enabled by technologies.
  • It has become relatively easy to construct systems which cannot be so readily understood. 
  • This leads to challenges throughout the life cycle of systems, including human ability to:
    • Design
    • Manufacture
    • Distribute
    • Maintain
    • Test
    • Operate
    • Use
    • Support
    • Diagnose
    • Describe, Specify
    • Predict
    • Modify
    • Extend
    • Decommssion
    • Dispose of 
  • The work of specialists in individual disciplines, such as mechanical, electrical, software, process, or other branches of engineering, materials science, human factors, quality, manufacturing, distribution, or other areas is challenging to coordinate, to obtain the overall results sought at acceptable cost, schedule, or risk.
  • Systems Engineering has emerged over the last half-century as an approach to these challenges, over the life cycle of human-engineered systems. 
  • Systems Science is emerging as a scientific and mathematical basis for understanding the systemic nature of natural and human-engineered systems.