Computers & Operations Research 36 (2009) 1740--1750 Contents lists available at ScienceDirect Computers & Operations Research journal homepage: www.elsevier.com/locate/cor Online decision making and automatic decision model adaptation  J ¨ orn Sch ¨ onberger ∗ , Herbert Kopfer University of Bremen, Chair of Logistics, Wilhelm-Herbst-Straße 5, 28359 Bremen, Germany ARTICLE INFO ABSTRACT Available online 1 May 2008 Keywords: Transportation Vehicle routing Online optimization Adaptation Dynamic decision problem Supply chain The paper investigates an online version of the vehicle routing problem with time windows, in which additionally arriving requests cause the revision of so far followed routes and schedules. An extended online optimization framework is proposed, which automatically adapts to problem variations and en- ables the explicit consideration of up-to-date knowledge about the current performance of the controlled system. Actually, we use the mean punctuality observed in the transportation system to adjust the ob- jective function utilized for solving the next decision problem instance. The search is guided toward least cost solutions coming along with high punctuality. We prove the applicability of this approach within comprehensive numerical experiments. © 2008 Elsevier Ltd. All rights reserved. 1. Introduction The supply chain of a product describes the sequence of activ- ities to be carried out in order to create the desired output from one or several inputs factors. Supply chain planning (SCP) aims at achieving the highest possible efficiency of a supply chain by coordi- nating and consolidating the necessary material flows ("processes'') so that economies of scale are exploited to the largest possible extent. Recent trends in the management of supply chains compromise the successful application of existing concepts for computational planning support. • The ability to consider unexpected events in an ad hoc fashion is propagated as significant competitive advantage. The continuous incorporation of recent problem data requires a continuous plan revision. • The partners forming the supply chain are not willing to give up the responsibility and self-reliance for the material flow decisions in their part of a supply chain. Consequently, the cen- tralized supply chain wide top-down material flow determina- tion and the goals of the incorporated partners are sometimes contradicting.  This research was supported by the German Research Foundation (DFG) as part of the Collaborative Research Centre 637 "Autonomous Cooperating Logistic Processes'' (Subproject B7). ∗ Corresponding author. Fax: +49 421 218 4271. E-mail addresses: jsb@uni-bremen.de (J. Sch ¨ onberger), kopfer@uni-bremen.de (H. Kopfer). 0305-0548/$ - see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.cor.2008.04.009 Contracts between supply chain partners are fixed for several months and must consider both the responsiveness of the involved partners to dynamics (e.g. demand variations and peaks) and the partners' autonomy in the operational deployment planning. Although a sup- ply chain is built by independent partners, one of them, the supply chain coordinator is dedicated and entitled to persuade the indepen- dent partners to behave and act in the sense of the superior supply chain goals instead of the subordinate partner's aims. Computer-supported decision making is necessary for all supply chain partners. The definition of a suitable mathematical decision model is a prerequisite for the successful application of automatic decision making tools like optimization algorithms. How- ever, the fine-tuning of such a model is a sophisticated task that typically requires some trial-and-error runs in order to identify the best parameter setting. Solving a concatenated sequence of decision problem instances is referred to as online optimization. The defini- tion and the solving of a new instance are triggered by events that compromise the realization of the so far optimal solution. There is no time to experiment on the right parameters for the decision model of the new problem. Here, the right parameters have to be adjusted automatically. Within this article, we investigate the impacts of different con- figurations for the interaction between the supply chain coordinator and a transport-providing partner in a given supply chain. We ana- lyze the implications of different intervention rights that enable the coordinator to bias the planning decisions of the transport partner by adjusting relevant decision model parameters. We show that a performance-oriented adaptation of the transport partner's decision logic has positive impacts on the overall supply chain reliability. An extension of the well-established online decision making frame- work is proposed. It enables a planning system of the coordinator to