RULES FOR THE IDENTIFICATION OF PORTFOLIO-INCOMPATIBLE REQUESTS IN DYNAMIC VEHICLE ROUTING

In this article, we propose and evaluate simple rules for selecting transport requests that do not fit into a request portfolio because their temporal or spatial requirements are incompatible with the requirements of other requests so that the compilation of profitable routes is compromised. We integrate these rules into an adaptive online vehicle operations planning system and analyze in numerical simulation experiments how their application has impacts on the flexibility, the stability and the profitability of the controlled transportation system and the integration of consecutively arriving requests

An instance data repository for the round-robin sports timetabling problem

The sports timetabling problem is a combinatorial optimization problem that consists of creating a timetable that defines against whom, when and where teams play games. This is a complex matter, since real-life sports timetabling applications are typically highly constrained. The vast amount and variety of constraints and the lack of generally accepted benchmark problem instances make that timetable algorithms proposed in the literature are often tested on just one or two specific seasons of the competition under consideration. This is problematic since only a few algorithmic insights are gained. To mitigate this issue, this article provides a problem instance repository containing over 40 different types of instances covering artificial and real-life problem instances. The construction of such a repository is not trivial, since there are dozens of constraints that need to be expressed in a standardized format. For this, our repository relies on RobinX, an XML-supported classification framework. The resulting repository provides a (non-exhaustive) overview of most real-life sports timetabling applications published over the last five decades. For every problem, a short description highlights the most distinguishing characteristics of the problem. The repository is publicly available and will be continuously updated as new instances or better solutions become available

Operational freight carrier planning: basic concepts, optimization models and advanced memetic algorithms

The modern freight carrier business requires a sophisticated automatic decision support in order to ensure the efficiency and reliability and therefore the survival of transport service providers. This book addresses these challenges and provides generic decision models for the short-term operations planning as well as advanced metaheuristics to obtain efficient operation plans. After a thorough analysis of the operations planning in the freight carrier business, decision models are derived. Their suitability is proven within a large number of numerical experiments, in which a new class of hybrid genetic search approaches demonstrate their appropriateness

(Re-)Allokationsstrategien für Aufträge mit alternativen Ausführungsmodi – Simulationsexperimente zur Transportlogistik

Volatile Entscheidungskonstellationen werden typischerweise als eine Sequenz miteinander verknüpfter statischer Entscheidungsinstanzen (d.h. als Online-Entscheidungsproblem) repräsentiert. Diese Instanzen werden sukzessive bearbeitet. Eine wesentliche Herausforderung, die bei der Definition von Entscheidungsunterstützungssystemen für Online-Entscheidungsprobleme bewältigt werden muss, besteht in der Bewältigung der logischen Abhängigkeiten zwischen den nacheinander bearbeiteten Instanzen. In diesem Artikel untersuchen wir ein Online-Entscheidungsproblem aus der Transportlogistik. Es wird untersucht, ob einmal getroffene Allokationsentscheidungen in späteren Instanzen modifiziert oder beibehalten werden sollten. Verschiedene Re-Allokationsstrategien werden vorgeschlagen und in computerbasierten Simulationsexperimenten evaluiert