Uwe Clausen

Optimizing the Door Assignment in LTL-Terminals

In less-than-truckload (LTL) terminals, arriving trucks have to be assigned to inbound doors and to suitable time slots for unloading. Simultaneously, waiting trucks have to be allocated to outbound doors. During a couple of hours, shipments from all incoming trucks are unloaded, sorted according to their relation, transported to the right outbound door, and loaded on the outgoing truck. (The term “relation” is an equivalent for destination; it originates from the German logistics vocabulary that uses the term to specify a certain transport offered between a source and a sink.) The first and the most important optimization aim is to minimize the total distance when transshipping units, because this leads to reduction in operational costs, which are usually very high. The second, and minor, aim is to minimize the waiting time for each truck. Usually the operator of an LTL transshipment building works with subcontractors when collecting and delivering goods. Therefore, no penalties have to be paid by the operators in case waiting times are too long. The logistical optimization task is modeled as a time-discrete, multicommodity flow problem with side constraints. Based on the applicable model, a decomposition approach and a modified column-generation approach are developed. In parallel, an evolutionary algorithm (EA) was implemented to tackle the problem at hand. Both algorithms---from the field of discrete mathematics, as well as from the field of computational intelligence---are applied to 10 test scenarios. A comparison of the solution process, as well as a comparison of the solution quality, concludes the work.

Heuristics for solving a capacitated multiple allocation hub location problem with application in German wagonload traffic

Abstract In this paper, we present a capacitated multiple allocation hub location problem, which arose from a network design problem in German wagonload traffic. We develop heuristic solution approaches based on local improvements. We solve the problem with the heuristics and CPLEX on test data sets provided by our partner Deutsche Bahn AG. The computational results are presented and compared.

Hub location problems with choice of different hub capacities and vehicle types

Hub-and-spoke networks have wide (logistical) applications, e. g. , in air and cargo transportation, post delivery, and telecommunication systems. In these networks transport volume is specified as flow between several origins and destinations. Hubs are specific facilities that serve as sorting, handling, transfer, and distribution points. In hub-and-spoke networks, flows with different origins and destinations are consolidated in hubs. Consolidation of flows in hubs may decrease transportation costs but increase additional costs due to establishing and operating hub facilities. Hub location problems deal with the location of hubs and allocation of origin-destination nodes to hub nodes in order to route the demand of each origin-destination pair through the network. In this paper, we extend the classical capacitated hub location problem. For each potential hub node we consider a set of different capacity levels which can be chosen. Besides, we consider the choice of different vehicle types of different capacities and costs to model more realistic costs. We present a single and a multiple allocation version. We implement the resulting integer programs in GAMS and solve them with CPLEX.

Logistics and Supply Chain Innovation: Bridging the Gap between Theory and Practice

This contributed volume presents state-of-the-art advances in logistics theory in various fields as well as case studies. The book reports on a number of recently conducted studies in the Dinalog and the Effizienz Cluster Logistik Ruhr, thus bridging the gap between different perspectives of theoretical and applied research. A selection of theoretical topics, practical examples, case studies and project reports is presented in this volume. The editors carefully selected contributions from a wide variety of projects, which were carried out in both the Dinalog cluster and the Effizienzcluster Logistik Ruhr. The contributions are grouped in five main sections, each representing key domains in the evolution of logistics and supply chain management: sustainability, urban logistics, value chain management, IT-based innovation, knowledge management. This book is intended for both researchers and practitioners in the field of logistics and supply chain management, to serve as an important source of information for further research as well as to stimulate further innovation.

A Compact Linearisation of Euclidean Single Allocation Hub Location Problems

Abstract Hub location problems are strategic network planning problems. They formalise the challenge of mutually exchanging shipments between a large set of depots. The aim is to choose a set of hubs (out of a given set of possible hubs) and connect every depot to a hub so that the total transport costs for exchanging shipments between the depots are minimised. In classical hub location problems, the unit cost for transport between hubs is proportional to the distance between the hubs. Often these distances are Euclidean distances: Then it is possible to replace the quadratic cost term for hub-hub-transport in the objective function by a linear term and a set of linear inequalities. The resulting model can be solved by a row generation scheme. The strength of the method is shown by solving all AP instances to optimality.

Modeling of handling task sequencing to improve crane control strategies in container terminals

Free space to expand the handling area in a container terminal is often not available. Therefore terminal operators have to improve operating strategies to increase the capacity of the terminal. For this purpose the authors developed a handling task sequencing strategy with a priority number for a multi crane module in a container terminal. In this paper this control strategy is compared with other state of the art control strategies to find out which crane control strategy is the best strategy for a container terminal. State of the art strategies only consider terminal specific requirements like travel time improvement, but a container terminal is also subject to market requirements such as short waiting times of the vehicles. Those requirements for terminals are often different so that a handling task sequencing is required which can be adjusted to the specific needs of a terminal.

Entwicklung eines Konzepts zur Innenstadtbelieferung mittels Elektromobilität

In Zeiten des Klimawandels und der Verknappung von endlichen Ressourcen ruckt der Begriff Elektromobilitat immer mehr in den Fokus groser Industrienationen. Vgl. Clausen (2008, S. 16 ff.) [1]. Die Bundesregierung plant, dass im Rahmen des „Nationalen Entwicklungsplans Elektromobilitat“, welcher im August 2009 verabschiedet wurde, bis 2020 eine Million Elektrofahrzeuge in Deutschland verkehren. Die finanzielle Forderung des Bundes durch 500 Millionen Euro soll die kurzfristigen Ziele unterstutzen und in Form eines Dreistufen-Plans die Marktreife von Elektrofahrzeugen realisieren und somit eine breite Marktdurchdringung ermoglichen. Die finanzielle Forderung wird dabei besonders fur Forschung und Entwicklung von Elektrofahrzeugen und deren Komponenten eingesetzt. In der ersten Phase des Entwicklungsplans werden seit 2009 in acht Modellregionen in Deutschland Mobilitatsprojekte gefordert. So werden die Implementierung von Ladeinfrastruktur, der Einsatz von Elektrofahrzeugen sowie neue Konzepte der City-Logistik untersucht. Ob die Elektromobilitat jedoch auch vor dem Hintergrund der Energiewende in Deutschland weiterhin als Schlussel fur die Losung der Umwelt- und Klimaproblematik gesehen werden kann, bleibt abzuwarten. Einen (noch) erstaunlich geringen Stellenwert scheinen in dieser Diskussion die (heute schon) in hoherem Mase elektromobilen offentlichen Personenverkehrssysteme sowie der Wirtschaftsverkehr zu haben. Lieferfahrzeuge nehmen insgesamt bisher nur eine untergeordnete Rolle gegenuber den Pkw in den Projekten zur Elektromobilitat ein. Vgl. Swantusch (2010, S. 22 f.) [2], Simon (2009, S. 29) [3], Becker (2010, S. 148) [4]. Die oft klarer definierten Einsatzzwecke und -radien legten eigentlich ein tendenziell groseres Nutzenpotential im Vergleich zum Individualverkehr nahe, sodass es notwendig und lohnend erscheint, neue Konzepte im Bereich der Ver- und Entsorgung in Stadten integriert mit den einhergehenden Charakteristika von Lieferfahrzeugen der Elektromobilitat zu berucksichtigen. Vgl. Clausen (2011) [5]. Besonders im Funktionsraum der Innenstadt sowie in Ballungsgebieten ist die Anwendung der Elektromobilitat aufgrund der spezifischen Umweltsituation sinnvoll und erfordert dabei eine Erweiterung bzw. Neuinterpretation des Begriffs der City-Logistik. Vgl. Kummerlin (2009, S. 6) [6].

Logistics Research and the Logistics World of 2050

Without doubt the logistics industry as well as logistics research are a central element of worldwide business structures and societal welfare. Therefore increasing interest and funding is directed towards innovative research in logistics – sustaining the broad expectations towards this sector in providing economic cost-effective as well as sustainable transport chains for global value chains. The challenge to provide even more availability with less resources and even less environmental impact will be crucial for industrial nations as well as developing countries – access to markets at reasonable transport prices is a cornerstone for the benefits of globalization. One major research initiative in this area is the EffizienzCluster LogistikRuhr established 2010 in Germany with international network links. This overview connects logistics trends and innovation expectations with the research objectives and structure of this cluster in order to clarify the eminent research agenda in logistics.

Efficiency in Logistics Facilities

Resulting from an increase of shipment quantities many logistics facilities (e.g., terminals, distribution centers, or production sites) reach their performance limit and thus become bottlenecks in supply chains. This is endangering defined cost and service goals and therefore the aim of the project “Efficiency in Logistics Facilities” is to develop a suitable modular software tool for the control of large logistics facilities. The developed technologies will increase the amount of available information at logistics facilities including shipment data and properties (e.g., volume, form, and handling requirements) in relation to resources and their current status.

Development of priority rules for handlings in inland port container terminals with simulation

A container terminal is a complex system with many subsystems, for example stacking area, cranes and vehicles, and a large number of decisions for each subsystem. Due to the interactions of these subsystems, there is a lot of stochastic influence and interdependencies within the decisions, which make an optimized operation of a whole container terminal very complex and without technical and methodical support hard to handle. One optimal operated subsystem influences all other subsystems and therefore does not result in an optimality for the whole system. To optimize the operations in an overall system with all its stochastic influence and interactions the method of simulation is used in this paper, which provides the opportunity to create an experimental model and identify the best recommended course of action. The Institute of Transport Logistics developed the simulation suite ContSim, which permits the modelling and simulation of material and information flows in a container terminal. ContSim provides the possibility to model a terminal on a microscopical layer. All handling and controlling processes of the terminal can be modelled and parameterized.