Complexity analysis in health informatics

Abstract

Complexity can be interpreted as a manifestation of the intricate entwining or inter-connectivity of elements within a system and between a system and its surroundings. Complex adaptive systems (CAS) are comprised of multiple subsystems that exhibit nonlinear deterministic & stochastic characteristics, and are regulated hierarchically. Examples of CAS include stock markets, human heart or brain, weather and climate systems, internet etc. A system’s complexity usually reflected in the dynamical fluctuations of the output generated by the free-running conditions. In this chapter, the definitional controversies for complexity are introduced and signal properties associated with complexity are reviewed. We then introduce some criteria used to classify complexity measures in the literature, and finally some representative complexity measures used in health informatics are described.