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Item type:Publication, Access status: without files , Logistic operating curves for closed queueing systems: Enhancing container terminal productivity through shared queuesContainer terminals are vital nodes in global supply chains, linking maritime and land transport. Terminal operators face the critical challenge of balancing vessel handling times and operational costs – a conflict of objectives. Building on our previous work that introduced an engineering-oriented approach using Logistic Operating Curves and an extended Kingman approximation for ship-to-shore crane productivity under fixed vehicle allocations, this paper advances the model to accommodate shared vehicle queues. In such configurations, terminal trucks serve multiple ship-to-shore cranes from a common pool, preserving the closed queueing system characteristics inherent to terminal operations.Publicationtype: Conference Paper32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Assignment of orders in horizontal transport at sea-port container terminals(Springer Nature Switzerland, 2026-07-09); ; ; ; Quay cranes (QCs) represent the primary operational bottleneck at seaport container terminals due to their high capital intensity and role as critical nodes in global supply chains. Their productivity is strictly dependent on the efficient coordination of horizontal transport, specifically the assignment of transport orders to terminal trucks (TTs). While many terminals still rely on fixed TT-to-QC assignments, this approach often lacks the flexibility to handle disruptions and fluctuating workloads. This paper investigates the potential of a flexible, multi-criteria assignment procedure – considering work-in-process, travel distances, and QC waiting times – compared to traditional fixed assignments. The performance is evaluated using Logistic Operating Curves (LOCs), which map QC productivity against the number of deployed TTs. The results demonstrate that flexible assignment significantly outperforms fixed assignment in underload scenarios (low TT availability or high travel speeds), showing productivity gains of up to 17.85% during vehicle disruptions. However, this advantage diminishes as transport capacity increases. In high-utilization overload zones, the flexible method falls slightly below fixed assignment performance. This discrepancy is attributed to the timing of order assignment; making decisions when a previous task is completed, rather than at the last possible second, limits the system’s ability to react to real-time fluctuations. The study concludes that flexible assignment increases robustness during transport shortages, but achieving theoretical productivity benchmarks requires shifting toward late-assignment strategies.Publicationtype: Conference Paper74 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modelling of logistics objectives at the sea side of container terminalsIn the context of the expanding global economy, the significance of transport chains has been increasingly recognized, with container terminals assuming a pivotal role within these networks. The competitive environment has led to pressure on these terminals, giving rise to a conflict of logistical objectives such as short vessel handling times and minimized handling costs. Previous attempts to address this issue, including simulation studies and deterministic mathematical models, have yet to be effectively implemented in practical settings due to their sensitivity to parameters and inherent complexity. This study proposes a novel engineering-centred approach utilizing Logistic Operating Curves to model terminal objectives, with a particular emphasis on quayside operations such as container handling by ship-to-shore cranes and terminal trucks. The paper explores the derivation of ideal and real Logistic Operating Curves for ship-to-shore cranes. Therefore, the well-known Kingman equation is extended to map the special characteristics of a closed queueing system. The simulation experiments conducted demonstrate that the proposed model provides sufficient accuracy in predicting mean productivities. The study concludes that the Logistic Operating Curves framework serves as an effective, understandable and adaptable method for improving terminal operations and highlights areas for further research.Publicationtype: Conference Paper120 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Betriebskennlinien für Portalkrane – Analyse der Leistungsfähigkeit von Umschlagterminals zur Steuerung der Lkw-AnkünfteIn the “BePoT” research project, the Funnel model from production logistics was successfully transferred to the gantry crane operations of a combined transport terminal. Based on this, throughput diagrams and Logistic Operating Curves (LOCs) were derived for two main types of orders at combined transport terminals – crane orders and dispatch orders. On the one hand, these models make it possible to systematically and generally describe the logistics objective conflict between high mean crane output rate and short mean throughput times of crane and dispatch orders. On the other hand, they form the basis for the monitoring, utilization, and booking systems developed in the project. In addition, the research project developed partial models for three key types of operational waste at combined transport terminals – intermediate storage, restacking and empty crane runs – as well as for the corresponding improvement measures – direct transshipments, stacking logics and double cycles. These partial models describe the respective types of waste and improvement measures as a function of their control variables. On the other hand, by integrating them into the LOC models, it is possible to describe the individual effects and the overall effect on the logistics objectives of combined transport terminals. The results achieved in the project show that these improvement measures have great potential to increase the handling performance and to defuse the logistics objective conflict in combined transport terminals.Publicationtype: Project Deliverable73 27 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Simulation-based analysis of conflicting objectives of quay cranes and terminal trucks at container terminals(Technische Universität Dresden, Fakultät Maschinenwesen, Institut für Technische Logistik und Arbeitssysteme, Professur für Technische Logistik, 2025); ; ; ; Quay cranes are essential operating systems at container terminals. Their scheduling involves conflicting objectives, such as minimising vessel handling times, maximising productivity, and reducing the number of required terminal trucks. Logistic Operating Curves, known from production logistics, offer a suitable method for analysing such trade-offs and can be derived and validated through simulation. This paper proposes a simulation model of a container terminal to develop and parameterise characteristic Logistic Operating Curves. The analysis focuses on the conflict between quay cranes productivity and number of terminal trucks. Different assignment procedures for terminal truck are considered to examine their impact on system productivity.Publicationtype: Conference Paper63 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modeling of logistics objectives at rail-road inland transshipment terminals(Springer, 2024-09-08); ; ; The logistics performance of inland transshipment terminals, such as rail-road container terminals, is crucial for establishing a reliable combined transport and for accomplishing sustainability goals. Main logistics objectives, such as high output rate and short throughput times, cannot be achieved simultaneously, creating an objective conflict. Modeling the interdependencies between the objectives can support terminals in determining an optimal operation point depending on their goals. Previously, these interdependencies have been analyzed primarily using complex simulation or optimization models. This paper presents an approach to model these interdependencies using Logistic Operating Curves (LOCs) and validates it using simulation.Publicationtype: Conference Paper85 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Untersuchung von Doppelspielen eines Portalkrans auf Umschlagterminals(Selbstverlag der Technischen Universität Dresden, 2024-03-12); ; ; ; Die Leistungsfähigkeit von Umschlagterminals ist ein wichtiger Faktor für die Wettbewerbsfähigkeit und die Attraktivität des Kombinierten Verkehrs (KV). Dieser kann einen wichtigen Beitrag zur Erfüllung der Nachhaltigkeitsziele Deutschlands leisten. Wichtigstes Arbeitssystem von KV-Umschlagterminals ist häufig ein Portalkran. Seine Leistung beeinflusst die Abfertigungsleistung eines Terminals und somit des Kombinierten Verkehrs. Steuerungsstrategien der Portalkrane können helfen, die Abfertigungszeit der Verkehrsträger, den Energiebedarf und die Betriebskosten der Krananlagen zu reduzieren und logistische und betriebswirtschaftliche Zielerreichung eines Terminals zu verbessern. Eine dieser Strategien ist die Doppelspielstrategie. Bei der Doppelspielstrategie erfolgen Beladungen und Entladungen der Verkehrsmittel alternierend mit dem Ziel, Leerfahrtzeiten zu reduzieren. Ziel dieses Beitrags ist es, den Einfluss der Doppelspiele auf die Kranleistung und den Energiebedarf der Krananlagen zu untersuchen und ihren optimalen Einsatz im operativen Kranbetrieb zu diskutieren.Publicationtype: Conference Paper29 53 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Logistics Objective conflicts at intermodal terminals(Thüringer Universitäts- und Landesbibliothek Jena, 2023-09-13); ; ; Gantry cranes are essential working systems at intermodal terminals. Their operation faces conflicting logistical objectives, such as improving the throughput time of the loading units, increasing the handling output, or reducing the waiting times of vehicles. Possible methods for analysing such conflicting objectives are Logistic Operating Curves (LOC) and throughput diagrams, which have found application in production logistics and can be derived and verified using simulation. In this paper, a simulation model for intermodal terminals is proposed to parameterize characteristic LOC. The LOC are used to analyse the conflict between the target values of a high output rate and a low throughput time.Publicationtype: Conference Paper24