Associate 2011-12

Harry Dankowicz

Mechanical Science and Engineering

On the Tendency of Complex Systems to Evolve Toward Collapse

Traditional measures of the robustness of complex systems focus on the long-term response to small fluctuations. Evidence from real-world complex systems (the international framework regulating environmental exploitation and resource allocation, for example) suggests that an increased emphasis should be placed on the short-term response to such fluctuations. In instances of increased volatility, such fluctuations may grow rapidly over the short term, far outpacing the decay rates associated with the long-term response and steadily eroding the vitality of the system.

During his Center appointment Professor Dankowicz is examining questions of robustness and stability in relation to complex social networks that evolve through cooperation, competition, and conflict among a large number of participants (frameworks for international security, for example). In particular, how can we recognize and assess risks to a (social) system’s sustained vitality when its individual parts (agents) seek to exploit local fluctuations for short-term gain?

In the recent global financial crisis, for example, enough individuals sought to capitalize on local fluctuations, thereby exacerbating their effects, ultimately bringing the whole system to the brink of collapse. A similar scenario plays out in the global balancing of growth, its repercussions on the natural environment, and continuing challenges to human and national sustainability and security. By first characterizing the robustness of complex systems, Professor Dankowicz aims to eventually develop a quantifiable measure of systemic risk and explore its use in the successful design of robust complex systems.

His project team will begin by developing models that account for the social network structure of system agents, the rule-based actions engaged in by these agents in response to their individual states and network connectivity, and the changes in network valuations that result. One avenue they plan to explore involves introducing an online game environment within or similar to the FarmVille game available on Facebook. Here, local players can choose short-term gains at the possible expense of long-term stability.