NewL_2-instability criteria for large-scale interconnected systems

In this paper, we derive several new criteria for the
L_2
- Instability of large-scale interconnected systems. These fall into two categories: the first set of results is based on the idea of dissipativity, while the second set is based on an orthogonal decomposition of the input space. The latter results have the advantage that they can be readily converted into
L_{\infty}
-instabiity criteria using the technique of exponential weighting. The former results are more general, but provide only
L_2
-instability criteria and no
L_{\infty}
-instability criteria.