A quiet revolution – the science of complex systems
Box 2 | Building reliable networks
Scientists who study complex systems are helping us to understand what’s needed to design networks that can cope with a range of disturbances.
Modern society depends on the reliable delivery of power, water, telecommunications, finance and government. It’s easy to visualise these services as being delivered to us via a network. To guarantee that these systems don’t shut down from small disturbances – such as the failure of a few components – care must be taken in the way components are connected to each other.
An example of the fragility of our large scale infrastructure networks occurred in August 1996, when the western United States power grid collapsed. A sagging power line touched a tree limb, causing a short circuit that triggered a cascading failure, where the backbone of the power grid fell like dominoes. Within minutes, the failure swept across Idaho, Utah, Colorado, Arizona, New Mexico, and Nevada, fracturing the entire system into four disconnected islands, leaving 7.5 million people without power and incurring a damage bill of US $2 billion.
The power grid was designed for the efficient delivery of electricity, with little thought given to redundancy. The drive for efficiency produced unintended consequences by increasing the vulnerability of the system and the risk of failure.
Boxes
Box 1. Complex systems, resilience and ecological sustainability
Box 3. It's a small world after all
Posted October 2006.