Modelers often rely on robustness analysis, the search for predictions common to several independent models. Robustness analysis has been characterized and championed by Richard Levins and William Wimsatt, who see it as central to modern theoretical practice. The practice has also been severely criticized by Steven Orzack and Elliott Sober, who claim that it a non-empirical form of confirmation...

This paper proposes a new logic RoCTL* to model robustness in concurrent systems. RoCTL* extends CTL* with the addition of Obligatory and Robustly operators, which quantify over failure-free paths and paths with one more failure respectively. We present a number of examples of problems to which RoCTL* can be applied. The core result of this paper is to show that RoCTL* is expressively equivalen...

The concept of robustness in the context of most work in Alife and complex systems implies that the results of a given model remain consistent despite unexpected variation. For example, homeostatic coupling between an animat and the environment is one possible simple form of robustness which we have demonstrated in simple simulation models (Ikegami et al., 2008, BioSystems, 91, p. 388), in whic...

Gain and time-constant factors shift the inverse process relative to its feedback controller. A new robustness plot cross-graphs these shift factors that take the loop to the stability boundary as a function of frequency.