Friday, 25 December 2015

Relationship Between Self-Organization and Emergence

The concept of Emergence (emergere, lat. : to appear, being produced, come into existence) has been known to the ancient Greek already and can be found throughout a large number of scientific fields, e.g. psychology, biology, physics and many more.

The best-known definition of emergence is that, "the sum is more than the whole of its parts". In the context of self-organization this means that the behavior of a system as a whole:


                            • Arises from the interactions of its parts.

                            • Seems not to resemble to the behaviors of its parts.

                            • Is substantially more complex than the bahavior of its parts.


The term of Self-organization is more widely used than the one of Emergence. It is also interpreted in different ways.

In general, "Self-organization"    serves as a super ordinate concept for a variety of natural self-organizing systems. Moreover it is used to classify distributed computer systems and algorithms that seemingly "exhibit" self-organizing properties.

Hermann et al. give a formal definition of self-organization. They introduce three criteria (Adaptivity, structure and decentralized control) by which they determine whether a distributed computer system should be labelled "self-organizing" or not. Unlike Emergence the notion of Self-organization is more often found when the adaptivity of a system and its sub-properties (e.g. self-optimization, self-configuration, self-healing and self-protection) are in focus.

In the context of Self-organization Emergence mostly is looked upon as a  synonym, a sub-super property, or a component. Holvoet and De Wolf take an interesting viewpoint towards these two concepts; they contrariously consider that Self-organization and Emergence represent two autonomous and independent concepts, each of them emphasizing different characteristics of a systems behavior. Refining both concepts with a set of sub-properties, they are able to identify systems that solely show self-organization or solely show emergence.


According to De Wolf and Holvoet the following aspects characterize emergent behavior:

- Micro-Macro-effect.
- Radical Novelty.
- Coherence.
- Interacting parts.
- Dynamical.
- Decentralized control: Because local interactions (only them) are responsible for global behavior, we say that the control of the system is distributed among its elements.

- Two-way link.
- Robustness and Flexibility: Decentralized control of the system contributes to its robustness, this is by the fact that a system is resistant to perturbations and have a strong capacity to restore its normal state in case of damages.


Self-organization on the contrary is characterized by:

- An increase in order.
- Autonomy.
- Robustness (with regard to changes).
- Dynamical (in the sense of far-from-equilibrium).



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