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Three inherent properties shared by all complex systems are complexity, emergent
behavior and composability from autonomous components [3]. Complexity refers to
the immense amount of information required to depict the system profile in terms of
macro and micro states. Emergent behavior in complex system refers to the ability of
the components of the system to change/evolve their structures and/or functions
without external intervention as a result of their interactions or in response to changes
in their environment. Emergent behavior can be classified as self-organization,
adaptation or evolution. Self-organization refers to changes in component individual
behavior due to inter-component communication, while adaptation refers to changes in
components' behavior in response to changes in the surrounding environment. Both
self-organization and adaptation imply information propagation and adaptive
processing through feedback mechanisms. Evolution of the network configuration report, on the other hand, refers to a
higher form of intelligent adaptation and/or self organization of components in
response to changes by accounting on previously recorded knowledge form past
experience(s). Evolution usually implies the presence of memory elements as well as
monitoring functions in evolvable components. Finally composability from
autonomous components implies the distributed structure of complex systems where
different entities collaborate to perform the global system function. Although
delineating the properties of complex systems are rather straightforward, yet designing
a system that exhibits these properties is a challenging task. This observation led us to
1) devise a network building block that we coin as the "network cell" by which we
build the network in an attempt to imitate natural complex systems' structure behavior
and capabilities; and 2) Adopt Separation of Concerns (SoC) as software engineering
methodology to tackle functional decomposition in networks yielding our proposed
CellNet framework that identifies Application, Communication, Resource and
Federation as four functional concerns.
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