Neon green light columns, arranged in a circle. They look like a cactus.

Controlling complex systems


power control

driver node

self-organized network


Control | video commentary by Albert-László Barabási

In »Control«, the BarabásiLab addresses the question of how complex, self-organized networks control themselves. Albert-László Barabási’s work assumes that the control of a system does not require authority over each individual element, but that a few elements—called driver nodes—can guide the dynamics of the whole system. In Barabási’s theory, each driver node controls a »cactus.« This term, borrowed from mathematics, denotes the connected sub-graph that represents the elementary units of control.

The visualizations in the light boxes show the field of cacti that determines the controllability of specific real networks, such as a network model or a communication or metabolic network. By depicting the forces necessary to control the respective networks, the hidden order behind controllability is made visible.