Triage strategies for agile core sorting in extreme value scenarios

Abstract: Surveys have indicated that the remanufacturing industry is concerned about the necessity of agile and prioritized core sorting due to its potential benefits to optimal core inventory and condition assessment, both at equipment and component levels. As such, core sorting holds a pivotal role in generalized remanufacturing operations, however, extreme value core arrivals, its stochastic nature and resulting sorting issues warrant targeted modelling and analysis. This paper is devoted to triage as an agile and quality-based sorting strategy in extreme value scenarios, which can be utilized as a complementary core sorting strategy. A statistical model of extreme core arrivals is developed based on Extreme Value (EV) theory and related Generalized Extreme Value (GEV) and Fr\'echet (Fisher-Tippett type-II) distributions. The model is applied to extreme arrivals of valves in an industrial valve repair shop in order to formulate extreme arrival sorting strategies. Using a large sample size, distribution parameters are estimated and the stochastic behaviour of the extreme valve arrivals is evaluated and verified. A generic analogy between medical triage and remanufacturing triage is discussed, because triage can be used to address extreme core arrivals, associated statistical distributions, and their effect on core condition assessment in order to enhance management of unpredictable consequences of extreme core arrivals.