Order allocation and sequencing with variable degree of uncertainty in aircraft manufacturing

A predictive–reactive approach for the sequencing of assembly operations in an automated assembly line

“…All the cited works address the optimization of the expected value of an objective function, e.g., the minimization of the expected completion time. Nevertheless, this does not protect against rare but very extreme scenarios, as discussed in Tolio et al (2011) and in Urgo et al (2018) for a generic production plan, in Urgo and Váncza (2014) for the single machine case, and in Alfieri et al (2012) and Manzini and Urgo (2015) with regards to Make-to-Order processes.…”

A Kronecker Algebra Formulation for Markov Activity Networks with Phase-Type Distributions

“…Although being a reasonable objective function, the expected value of the makespan, as well as any other objective function addressed in terms of its expected value, does not entirely model the stochastic nature of the problem. In fact, minimizing the expected makespan aims at ensuring an average good performance, but does not protect against the worst case scenario if their probability is low [14][15][16][17]. A balanced compromise between values and the impact of rare but unfavourable events typically requires knowledge of the distribution of the objective function under study.…”

An approach for the robust design of a reconfigurable assembly cell with 7-axis robot

“…This scheduling problem can be formalized as a Stochastic Resource-Constrained Project Scheduling Problem (Stochastic RCPSP ) whose main aim is to cope with the uncertainty and optimize the utilization of the equipment, i.e., minimizing the makespan to produce the entire batch. In a context where the use of human operators is considered, the expected makespan (e.g., (Möhring et al 2000) and (Radermacher 1985)) could not be the best choice in terms of target performance, because it does not protect against rare but very extreme scenarios (see (Tolio et al 2011) and (Urgo et al 2018) for a generic production plan, (Urgo and Váncza 2014) for the single scheduling problem and (Alfieri et al 2012) and (Manzini and Urgo 2015) with regards to Make-to-Order processes). To overcome these limitations, a proactive-reactive scheme (PR) grounding on the approach presented in Manzini et al (2018a) has been consider.…”