Don't just do something, stand there! Reflections on the counterintuitive behavior of complex systems, seen through the eyes of System Dynamics, Systems Thinking and simulation.
This is a new replication of a classic model, for the library. The model began in Nelson Repenning’s thesis, and was later published in Organization Science: A Simulation-Based Approach to Understanding the Dynamics of Innovation Implementation The history of management practice is filled with innovations that failed to live up to the promise suggested by … Continue reading “The Dynamics of Initiative Success”
The NYT has an interesting article on the difficulties of reforesting Iceland. This is an example of forest cover tipping points. Iceland appears to be stuck in a state in which “no trees” is locally stable. So, the system pushes back when you try to reforest, at least until you can cross into another basin … Continue reading “Reforesting Iceland”
Yasaman Jalili and David Ford look take a deeper look at project model dynamics in the January System Dynamics Review. An excerpt: Quantifying the impacts of rework, schedule pressure, and ripple effect loops on project schedule performance Schedule performance is often critical to construction project success. But many times projects experience large unforeseen delays and … Continue reading “Feedback and project schedule performance”
An interesting article in PLOS one explores the consequences of a system of random feedbacks: The Emergence of Environmental Homeostasis in Complex Ecosystems The Earth, with its core-driven magnetic field, convective mantle, mobile lid tectonics, oceans of liquid water, dynamic climate and abundant life is arguably the most complex system in the known universe. This … Continue reading “Random rein control”
There are warning signs when the active structure of a system is changing. But a new paper shows that they may not always be helpful for averting surprise catastrophes. Catastrophic Collapse Can Occur without Early Warning: Examples of Silent Catastrophes in Structured Ecological Models (PLOS ONE – open access) Catastrophic and sudden collapses of ecosystems … Continue reading “Early warnings of catastrophe”
Phase plots are the key to understanding life, the universe and the dynamics of everything. Well, maybe that’s a bit of an overstatement. But they do nicely explain tipping points and bifurcations, which explain a heck of a lot (as I’ll eventually get to). Fortunately, phase plots for simple systems are easy to work with. … Continue reading “Fun with 1D vector fields”
A while back, Bruce Skarin asked for an explanation of the bifurcations in a nuclear core model. I can’t explain that model well enough to be meaningful, but I thought it might be useful to explain the concept of bifurcations more generally. A bifurcation is a change in the structure of a model that brings … Continue reading “What the heck is a bifurcation?”
Taking my own advice, I grabbed a simple project model and did a Monte Carlo experiment to see if project performance had a heavy tailed distribution in response to normal and uniform inputs. The model is the project tipping point model from Taylor, T. and Ford, D.N. Managing Tipping Point Dynamics in Complex Construction Projects … Continue reading “A project power law experiment”
An interesting paper finds a heavy-tailed (power law) distribution in IT project performance. IT projects fall in to a similar category. Calculating the risk associated with an IT project using the average cost overrun is like creating building standards using the average size of earthquakes. Both are bound to be inadequate. These dangers have yet … Continue reading “Project Power Laws”
On the heels of the 40th anniversary of Limits to Growth, the Breakthrough crowd is still pushing a technical miracle, just around the corner. Their latest editorial paints sustainability advocates as the bad guys: Stop and think for a moment about the basic elements of the planetary boundaries hypothesis: apocalyptic fears of the future, a professed … Continue reading “The neo-cornucopians, live from planet Deepwater Horizon”