NP-completeness and other complexity proofs often merely State that the problem at hand is a generalization of some other intractable problem. This proof technique relies on the widely accepted assumption that complexity results hold regardless of the model formulation used to represent the...

This paper deals with lot sizing and scheduling for a single-stage production System where setup costs and times are sequence dependent. A large bücket mixed integer programming (MIP) model is formulated which considers only efficient sequences. A tailor-made enumeration method of the...

Nicht in erster Linie der Stoff macht das Wesen eines Faches aus, sondern das in ihm gepflegte Denken. ... Die Pflege des betriebswirtschaftlichen Denkens ist nach meiner Meinung neben der Forschungsarbeit die wesentliche Aufgabe der akademischen Betriebswirtschaftslehre. Nach unserer Meinung...

Im Bereich der Entwicklung elektronischer Leitstände werden derzeit große Anstrengungen unternommen, die Produktionsplanung und -steuerung wissensbasiert zu unterstützen. Von besonderem Interesse sind dabei Konzepte und Implementierungen wissensbasierter Leitstände zur Losgrößen-, Termin-...

A batch sequencing model with sequence-dependent setup-times and -costs is used to compare modelling and solving with two different general solvers. "Conceptual models" are implemented in the constraint propagation / logic programming language CHARME and solved with the PROLOG inference engine....

Lotsizing and scheduling comprises activities which have to be done repeatedly within MRP-systems. We consider the proportional (multi-item, capacitated, dynamic) lotsizing and scheduling problem which is more general than the discrete lotsizing and scheduling problem as well as the continuous...

Cellular automata were used to model and to simulate phenomena in the area of physics, biology and medicine. In this paper it is now shown how the idea of cellular automata can be applied to optimization problems as well. As an example a cellular automaton is used as a basis for solving...

A new model is presented for capacitated lot-sizing with sequence dependent setup costs. The model is solved heuristically with a backward oriented method; the sequence and lot-size decisions are based on a priority rule which consists of a convex combination of setup and holding costs. A...

The discrete lotsizing and scheduling problem with setup-times is transformed into a single-machine scheduling problem, denoted as batch sequencing problem, which integrates sequence-dependent setups as well. The relationship between the lotsizing and the batch sequencing problem is analyzed....

In machine tool assembly several make-to-order products have to be manufactured simultaneously in a multi-stage production system. Due to customer requirements batches are very small. A process plan specifies the neccessary machines, tools, auxiliary devices as well as the operations to be...