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Item type:Publication, Access status: without files , Hierarchical reinforcement learning for fleet control in multilayer container storage systemsPublicationtype: Journal Article7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Process structures and operational vulnerability in RoPax terminals: A qualitative analysisRoPax terminals play a critical role in European short sea shipping and intermodal transport systems, yet research on their internal operational processes remains limited. This paper reconstructs the process structures of RoPax terminals and analyses how differences between accompanied and unaccompanied traffic flows generate operational interdependencies and vulnerability. The study adopts a qualitative, process-oriented research design based on 29 semi-structured expert interviews with stakeholders involved in RoPax terminal operations. The interview data are analysed through inductive qualitative content analysis and iterative process reconstruction to identify recurring process structures, functional areas, control mechanisms, and bottlenecks. The findings show that RoPax terminal operations are organised around tightly connected functional areas, including gate and check-in, pre-staging areas, trailer yards, internal transport, ramps, and the vessel interface. Accompanied and unaccompanied traffic flows follow different process logics in terms of controllability, buffering capacity, sequencing requirements, and dependence on terminal-controlled resources. These differences create strong interdependencies between gate operations, yard management, internal transport, and ramp usage, leading to recurrent bottlenecks and coordination challenges under fixed sailing schedules and short port stays. The paper conceptualises RoPax terminals as coupled process systems in which operational vulnerability emerges from the interaction of heterogeneous traffic flows, shared interfaces, temporal compression, and soft control mechanisms. It clarifies why container-centric assumptions are only partially transferable to RoPax terminals and demonstrates how qualitative process reconstruction complements quantitative modelling by making implicit operational logics visible where empirical process-level analysis remains limited.Publicationtype: Journal Article5 3 - Some of the metrics are blocked by yourconsent settings
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 Paper31 - 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 , A novel approach to calculate fuel consumption of offshore wind operation and maintenance vessels using AIS dataOffshore wind is considered environmentally friendly; however, the logistics side involves a large number of vessels for operation and maintenance, contributing to greenhouse gas emissions which should not be overlooked. This paper presents a methodology for estimating fuel consumption and emissions of offshore wind service vessels operating in offshore wind farms by using Automatic Identification System (AIS) data. The approach accounts for ship resistance components, propulsion power requirements, and emission factors for multiple fuel types. Validation against real operational data of an offshore supply vessel shows close correlation, with fuel consumption estimates deviating by approximately 12.5% from recorded measurements. The findings underscore the potential of an AIS-based analysis to optimize fuel consumption and reduce emissions of offshore wind supply vessels.Publicationtype: Conference Paper41 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , An AIS-based analysis of the transfer of maritime pilotsThis study presents a systematic analysis of maritime pilot transfer operations using Automatic Identification System (AIS) data. Pilots are essential nautical service providers who enable safe navigation of ships during port calls. Their transfers are facilitated by pilot boats whose activities influence the efficiency of port calls. The methodological framework developed in this study segments ship trajectories of pilot boats into nine operational categories, with particular emphasis on embarkation and disembarkation. These events are detected using a ship domain–based identification method, enabling the recognition of transfer operations directly from AIS data. Data from three Scandinavian regions are analyzed over a ten-day period. These include ports within the Oslofjord, the port of Helsinki and the port of Copenhagen. Results show that pilot boats spend the majority of their time berthed, while embarkation and disembarkation constitute relatively small shares of total activity. Average transfer durations are approximately two to three minutes, with limited variation across ship size classes, though larger ships tend to require more time. Speed analyses further reveal distinct maneuvering phases, with higher speeds observed when a pilot is on board. The findings provide empirical reference values for pilot transfer operations and demonstrate the potential of AIS-based methods to enhance port call optimization.Publicationtype: Conference Paper33 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A multi-layer framework for modelling resilience in waterway-dependent supply chains using reliability theory : a case study of the West German canal system(2026)68 25 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Test and evaluation methodology for indoor localization systems in intralogistics(2026); The research, development, and application of Indoor Localization Systems (ILS) are hindered by the absence of adequate methods for Test and Evaluation (T&E). This dissertation tackles this challenge within the intralogistics context. It introduces methods for systematically designing test scenarios, for benchmarking, and for specifying location data requirements, which are integrated into a comprehensive T&E methodology. The contributions of this work enable stakeholders to meaningfully evaluate the performance of ILS and identify suitable systems for intralogistics applications, ultimately fueling the ongoing transition to a more interconnected and efficient industry.Publicationtype: Doctoral Thesis55 37 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , AI-based business models in manufacturing SMEs - A case study analysisBased on five case studies, this article exami nes the design of AI-based business models in manufacturing SMEs. Using the 4V model, structural implications are analy zed along the dimensions of value proposition, value delivery, value creation, and value capture. The findings reveal recur ring patterns of data-driven value creation and distinguishable factors shaped by industry context and organizational capabilities.Publicationtype: Journal Article38 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Design options to increase the efficiency of intra-port container transportsHigh volumes, short buffer times and many other players influence the maritime transport chain and intraport container transport. Congestion at logistics hubs leads to inefficient processes, increased waiting times, costs and emissions. Truck appointment systems are designed to reduce congestion by offering trucking companies time slots for delivering or collecting containers. However, these systems lack flexibility, which limits utilization and reduces efficiency. The study aims to develop strategies to evaluate and improve these systems in a simulation study. The results show that medium-length time slots improve the situation for transparent processes, or long time slots for limited transparency. Overbooking and open access are mutually exclusive, but offer slight advantages individually. Adjustments to opening hours of other nodes show little benefit. Overall, flexibility options positively influence the ratio of load trips and waiting times.Publicationtype: Conference Paper29