Scientists at Northeastern University and MIT devised a graphical approach that first derives the mathematical...

 Scientists at Northeastern University and MIT devised a graphical approach that first derives the mathematical equations describing a complex system's dynamics, and then determines the key sensors for that system. Moreover, when applying their approach to biochemical reaction systems, the researchers discovered that the derived sensors were both necessary and sufficient to describe the complete system.

 Read more here : http://phys.org/news/2013-03-sensor-complex.html