Logistics time-based approaches

Despite the clear benefits of time-based approaches to logistics management described above, there are often barriers to its application, as well as bmltations to its relevance. 

An age-based imperfect PM combined with CM replacements was modelled for an offshore wind turbine using GSPN with predicates coupled with MCS and considering the logistics, times and costs, and weather constraints. The PM repairs were modelled to be performed after a repair threshold age, p X MTTF, of the components. The failure models of the components were obtained from onshore ones using an empirical approach based on stress factors for mechanical systems. 

A corollary to the mechanisms of cell-death execution is that a dying cell does not need to reach a stable apoptotic state to be dead. This creates a logistical problem for many standard dynamical-systems approaches (nullclines, bifurcation analysis, etc.) that are based on steady-state solutions to the governing equations. Aldridge and coworkers applied finite-time approaches (that do not require d/df = 0) to define the separation of cellular trajectories in a model of caspase activation (Aldridge et al. 2006). These types of approaches may be particularly relevant for other irreversible cell-fate choices, such as during the mitotic-spindle checkpoint. 

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