Curtailing cascading failures

Cascading behaviors are ubiquitous, from power-grid failures (1) to “flash crashes” in financial markets (2, 3) to the spread of political movements such as the “Arab Spring” (4). The causes of these cascades are varied with many unknowns, which make them extremely difficult to predict or contain. Particularly challenging are cascading failures that arise from the reorganization of flows on a network, such as in electric power grids, supply chains, and transportation networks. Here, the network edges (or “links”) have some fixed capacity, and we see that some small disturbances easily dampen out, but other seemingly similar ones lead to massive failures. On page 886 of this issue, Yang et al. (5) establish that a small “vulnerable set” of components in the power grid is implicated in large-scale outages. Although the exact elements in this set vary with operating conditions, they reveal intriguing correlations with network structure.


 Curtailing cascading failures
Raissa M. D’Souza

Science  17 Nov 2017:
Vol. 358, Issue 6365, pp. 860-861
DOI: 10.1126/science.aaq0474


Small vulnerable sets determine large network cascades in power grids

Sometimes a power failure can be fairly local, but other times, a seemingly identical initial failure can cascade to cause a massive and costly breakdown in the system. Yang et al. built a model for the North American power grid network based on samples of data covering the years 2008 to 2013 (see the Perspective by D’Souza). Although the observed cascades were widespread, a small fraction of all network components, particularly the ones that were most cohesive within the network, were vulnerable to cascading failures. Larger cascades were associated with concurrent triggering events that were geographically closer to each other and closer to the set of vulnerable components.


Small vulnerable sets determine large network cascades in power grids
Yang Yang, Takashi Nishikawa, Adilson E. Motter


Winter School on Complexity Science

The 2018 Winter School provides an overview of complexity and complex systems science that empowers participants search for their own answers to these questions. The knowledge gained will enable participants to apply complexity science ideas in their own domains.

Essentially the school will:

teach basic aspects of complexity and complex systems, answering the question: What makes a system complex? Aspects that will be covered include nonlinearity, order disorder & chaos, emergence and complex adaptive systems
introduce methods, models and simulation tools to study the behaviours of complex systems and provide hands-on experience on through the use of software for building, simulating and visualizing complex networks. Participants are encouraged to bring their own data, work in groups mentored by instructors. Participants will then have the opportunity to present their own finding​s at the end of the week long course.
provide insights into how complexity manifests itself in real life e.g. politics & governance, eco-systems, cities and spreading phenomena such as rumours, epidemics, economics and innovation.


Winter School on Complexity Science

Date: 22-23 & 26-28 March 2018
Venue: Nanyang Executive Centre, NTU, Singapore


Re-conceptualizing the origins of life

Over the last several hundred years of scientific progress, we have arrived at a deep understanding of the non-living world. We have not yet achieved an analogous, deep understanding of the living world. The origins of life is our best chance at discovering scientific laws governing life, because it marks the point of departure from the predictable physical and chemical world to the novel, history-dependent living world. This theme issue aims to explore ways to build a deeper understanding of the nature of biology, by modelling the origins of life on a sufficiently abstract level, starting from prebiotic conditions on Earth and possibly on other planets and bridging quantitative frameworks approaching universal aspects of life. The aim of the editors is to stimulate new directions for solving the origins of life. The present introduction represents the point of view of the editors on some of the most promising future directions.


Re-conceptualizing the origins of life
Sara I. Walker, N. Packard, G. D. Cody
Published 13 November 2017.DOI: 10.1098/rsta.2016.0337