Look-ahead strategies for controlling batch operations in industry - overview, comparison and exploration

Batching jobs in a manufacturing system is a very common policy in most industries. The main reasons for batching are avoidance of set ups and/or facilitation of material handling. Good examples of batch-wise production systems are ovens found in aircraft industry and in semiconductor manufacturing. Starting from the early nineties much research efforts have been put in constructing strategies for the dynamic control of these systems in order to reduce cycle times. Typically, these so-called "look-ahead strategies" base their scheduling decision on the information on a few near future product arrivals. In this paper we give a literature overview of the developed strategies, evaluate their performance and explore their relevance for practical situations by means of a simulation study

Adaptive techniques for Evolutionary Topological Optimum Design

This paper introduces some advances in Evolutionary Topological Optimum Design, thanks to extensive use of adaptive techniques. On the genotypic side, a variable length representation is used: the complexity of the representation of each individual is evolved by the algorithm rather than being prescribed by some fixed mesh of the design domain, resulting in self-adaptive complexity. On the phenotypic side, an original adaptive mechanism is proposed that maintains both feasible and infeasible individuals, thus exploring both sides of the boundary of the feasible region, where the optimum structure is known to lie. Not only does this improves the results of past work in on Evolutionary Topological Optimum Design on standard benchmark bidimensional cantilever problems, but it also allows to address three-dimensional problems who had up to now stayed beyond reach for evolutionary algorithms