Ulrich John

Constraint-based configuration of large systems

Configuration processes in industry are complex and until now have been time-consuming and costly, even though computers are sometimes used. Furthermore, the configuration found is seldom an optimal or near-optimal solution. We developed a constraint-based system for expert driven configuration that yields good solutions in fairly quickly time depending on the information and the expert knowledge available. We have now extended this approach to deal with large systems consisting of hundred or thousands of components. We describe methods to limit memory-consuming processes and provide results for benchmark problems.

Integrating time constraints into constraint-based configuration models

Over the last few years, we have been developing the configuration model ConBaCon, which is based on Constraint Programming over finite domains. The model is sound and suitable for building efficient and flexible systems that fulfill all the requirements of advanced configuration systems. In this paper, we present model extensions that enable time-extended configuration and reconfiguration problems to be solved: Besides “normal” configuration and reconfiguration problems, the extended model can now also solve problems that contain time-dependent resource avaibilities or supply constraints for the ground components included. The general nature of the model extensions introduced seems to be suitable for integration in other (commercial) constraint-based configuration systems/configurator libraries as well.

Konfiguration komplexer Produkte mit Constraint-basierter Modellierung

Zusammenfassung. Industrielle Konfigurationsprozesse sind, bedingt durch die vorherrschende Variantenvielfalt, sehr komplex. Aufgrund der inhärenten Potentiale ist die Realisierung von effizienten, flexiblen Konfigurationsprozessen ein zentrales Ziel vieler Unternehmen. Wir haben einen Ansatz für die Konfiguration und Rekonfiguration von Produkten entwickelt, der auf Constraint-basierter Modellierung über endlichen Domänen basiert. Das auf diesem Ansatz beruhende System ConBaCon deckt eine breite Palette von Konfigurationsproblemen ab und ermöglicht eine effiziente Lösung, die sowohl automatisch als auch gesteuert durch hoch flexible Nutzerinteraktion erfolgen kann. Wendet man das System jedoch auf große Konfigurationsprozesse an, so treten Performanzprobleme auf. Als zwei wesentliche Modellerweiterungen, die diesem Mangel entgegenwirken, stellen wir in dieser Arbeit einerseits eine Modell-Clusterung und andererseits die Behandlung großer Netze arithmetischer Constraints vor.Abstract. The configuration of complex industrial products is often costly and inaccurate because of the numerous variants of products and their components. Improving the configuration of technical products using computer-supported methods is a prerequisite for modern, efficient and flexible customer-oriented production. We describe an approach to the configuration and reconfiguration of technical devices that is based on constraint programming over finite domains. The system ConBaCon, which uses this method, combines automatic processing with interactive user interactions. Benchmark tests are used to investigate the relations between the number of components, hierarchy depth and efficiency. Furthermore, clustering and special treatment of large networks of arithmetic constraints are presented as methods of dealing with high complexity.