TY - JOUR A1 - Staab, T. A1 - Klenk, Eva Marianne A1 - Galka, Stefan A1 - Günthner, Willibald A. T1 - Efficiency in in-plant milk-run systems - The influence of routing strategies on system utilization and process stability JF - Journal of Simulation N2 - In-plant milk-run systems represent transportation systems, where materials are delivered from a central storage area to several points of use on fixed routes and in short and defined intervals. Milk-run systems generally enable frequent deliveries in low lot sizes with short lead times and low inventories at the points of use. Thus, stable and reliable system operation is crucial to avoid delays and material shortages. In industrial practice, milk-run trains usually share resources, for example, loading areas and technology and use the same tracks, leading to dependencies between routes and possible traffic jams and blockages, which significantly affect cycle times and may lead to instabilities in the system. We present a simulation model to analyse in-plant milk-run systems with a focus on typical traffic situations. We describe its application to a large industrial case study in detail and derive recommendations for designing routes with low risk of delays. KW - logistics KW - traffic KW - simulation KW - production KW - vehicle routing KW - in-plant milk-run Y1 - 2016 U6 - https://doi.org/10.1057/jos.2015.6 SN - 1747-7786 SN - 1747-7778 VL - 10 IS - 2 SP - 137 EP - 143 PB - Taylor & Francis CY - Abingdon ER - TY - JOUR A1 - Schuhegger, Lukas A1 - Kara, Sinan A1 - Galka, Stefan A1 - Dünnweber, Jan A1 - Meißner, Sebastian T1 - Umzugsplanung mit Fabrikdatenmodellen und Virtual Reality JF - Zeitschrift für wirtschaftlichen Fabrikbetrieb N2 - Angesichts eines dynamischen industriellen Umfelds müssen produzierende Unternehmen flexibel bleiben und sich kontinuierlich anpassen, um ihre Wettbewerbsfähigkeit zu erhalten. Eine effektive Planung von Restrukturierungen in Produktionssystemen, oft als Umzugsplanung bezeichnet, ist entscheidend, um Verzögerungen zu vermeiden und Stillstandszeiten zu minimieren. Die Identifikation von Umzugsfällen, welche den Umfang umzuziehender Ressourcen wie Maschinen, Anlagen, Ausrüstungen und Arbeitsplätzen beschreiben und die Definition zugehöriger Aufgaben sind essenzielle Schritte der Umzugsplanung. Dieser Beitrag stellt eine Vorgehensweise zur Bestimmung von Umzugsfällen mittels eines Fabrikdatenmodells vor, ergänzt durch eine Visualisierung in Virtual Reality, um Planende bei der Umzugsplanung zu unterstützen. N2 - Given a dynamic industrial environment, manufacturing companies must remain flexible and continuously adapt to maintain their competitiveness. Effective planning of restructuring efforts in production systems, often referred to as reconfiguration planning, is crucial to avoid delays and minimize downtime. Identifying reconfiguration cases, which describe the scope of resources to be relocated, such as machines, equipment, and workstations, and defining the associated tasks are essential steps in reconfiguration planning. This paper presents an approach for determining reconfiguration cases using a factory data model, complemented by visualization in virtual reality, to support planners in the reconfiguration process. KW - Fabrikdatenmodel KW - Virtual Reality KW - Umzugsplanung KW - Restrukturierung KW - Umstellung KW - Factory Data Model KW - Reconfiguration Planning KW - Restructuring KW - Relocation KW - Virtual Reality Y1 - 2024 U6 - https://doi.org/10.1515/zwf-2024-1154 SN - 2511-0896 SN - 0947-0085 N1 - Corresponding author der OTH Regensburg: Lukas Schuhegger VL - 119 IS - 11 SP - 799 EP - 804 PB - de Gruyter ER - TY - CHAP A1 - Marinkovic, Minja A1 - Galka, Stefan A1 - Meißner, Sebastian T1 - Digital Twins for Internal Transport Systems: Use Cases, Functions, and System Architecture T2 - Proceedings of the 56th Hawaii International Conference on System Sciences: January 3-6, 2023, Maui, Hawaii, USA N2 - Internal transport systems are an essential part of intralogistics in production and distribution facilities. These are characterized by a variety of technologies as well as a multitude of interactions with other processes, such as warehouse, picking, and production processes. Therefore, resource planning and control of these systems is complex, especially for discontinuous conveyors. In this task, users can be supported by Digital Twins for decision-making, as they are suitable for investigating both future system states and possible actions. However, relevant use cases that are generally applicable across sectors as well as a generic system architecture for Digital Twins for resource planning and process control of in-plant transport systems have not yet been sufficiently investigated. In this paper, use cases are presented, relevant functions defined, and, finally, a generic functional and a logical reference architecture described. This is conducted with the design science in information systems research method together with a Systems Engineering approach. The use cases are determined at industrial partners of the research project TwInTraSys, which explores Digital Twins for the planning and control of internal transport systems. They are generalized and, thus, also applicable to other production and distribution facilities in different sectors. Further, the reference architecture can provide a basis for the successful implementation of the Digital Twin. KW - Intelligent Decision Support for Logistics and Supply Chain Management KW - intralogistics KW - internal transport systems KW - digital twin Y1 - 2023 SN - 978-0-9981331-6-4 SP - 1195 EP - 1204 PB - University of Hawaiʻi at Mānoa CY - Honolulu, HI ER - TY - CHAP A1 - Schmid, Florian A1 - Galka, Stefan A1 - Marinkovic, Minja A1 - Meißner, Sebastian ED - Bergmann, Sören ED - Feldkamp, Niclas ED - Souren, Rainer ED - Straßburger, Steffen T1 - Simulationsbasierte Untersuchung von Abstraktionsgraden im Kontext Digitaler Zwillinge für innerbetriebliche Transportsysteme T2 - Tagungsband 20. ASIM-Fachtagung Simulation in Produktion und Logistik, Ilmenau, 13. – 15. September 2023 N2 - Current challenges in the planning and control of internal logistics systems are based on permanent changes in the requirements on the system, e.g., due to fluctuating order numbers or changes in their structure. For the representation and planning of in-house logistics processes, digital twins offer the possibility to verify different operational decisions such as predictive workforce scheduling. In this context, the quality of the results and their in-time presentation plays a decisive role. However, both target criteria are influenced by the detail-level of the digital representation. Based on a case study, this paper investigates the influence of the level of detail on the simulation runtime and result divergence to provide an evaluation for detail levels in the modelling of intralogistic transport systems. T2 - Simulation-based Analysis of Abstraction Degrees in the Context of Digital Twins for Intralogistics Transport Systems Y1 - 2023 SN - 978-3-86360-276-5 U6 - https://doi.org/10.22032/DBT.57794 SP - 135 EP - 144 PB - Universitätsverlag Ilmenau CY - Ilmenau ER - TY - CHAP A1 - Galka, Stefan A1 - Schmid, Florian A1 - Grasser, Dominik A1 - Hohm, Jonathan A1 - Stauber, Stephan A1 - Meißner, Sebastian T1 - Integration eines SAP-Transportleitsystem in eine Simulationsumgebung zur Unterstützung von Entscheidungen im operativen Betrieb T2 - Tagungsband 20. ASIM-Fachtagung Simulation in Produktion und Logistik, Ilmenau, 13. – 15. September 2023 N2 - Digital twins enable the digital representation of physical systems and provide comprehensive modelling and analysis capabilities. An online data exchange between the Digital twin and SAP is feasible, through integration of a transport control systems (SAP) via RESTful API. This interface allows decision making in resource allocation and furthermore the adaptation of the digital model if the real system changes. Despite the associated challenges in terms of data synchronisation, the integration has benefits such as a reduction in modelling effort and an increase in the lifetime of the digital twin. In the context of this work, the design of the interface between the simulation software and a SAP transport control system via RESTful API is described. Y1 - 2023 SN - 978-3-86360-276-5 U6 - https://doi.org/10.22032/DBT.57813 SP - 281 EP - 291 PB - Universitätsverlag Ilmenau CY - ILmenau ER - TY - CHAP A1 - Galka, Stefan A1 - Weigert, Alexander ED - Schmidt, Thorsten ED - Kühn, Mathias ED - Rank, Sebastian T1 - Systematik zur planungsbegleitenden Simulation bei der Konzeptplanung von Produktionssystemen – ein Anwendungsfall aus der Elektrolysestack-Produktion T2 - Simulation in Produktion und Logistik 2025 N2 - Simulation can support early-stage production system planning by enabling efficient evaluation of concept variants. However, detailed models are often impractical in concept phases due to limited data and high modelling effort. This paper presents a structured three-stage simulation approach for supporting the concept planning of water electrolyzer stack production systems . The approach leverages automatic model generation from formal process descriptions and gradually increases model detail across stages, carried out through a custom-developed simulation framework. This enables early validation of the throughput capability, resource planning, and the analysis of stochastically occurring technical malfunction. The method aims to reduce planning time while improving decision quality. KW - Produktion, Simulation, Petri-Netz Y1 - 2025 SN - 978-3-86780-806-4 U6 - https://doi.org/10.25368/2025.278 SP - 45-1 EP - 45-10 PB - Technische Universität Dresden, Professur für Technische Logistik CY - Dresden ER - TY - CHAP A1 - Galka, Stefan A1 - Meißner, Sebastian ED - Schmidt, Thorsten ED - Rank, Sebastian ED - Kühn, Mathias T1 - Einsatz von Digitalen Zwillingen für die operative Steuerung von innerbetrieblichen Transportsystemen T2 - Simulation in Produktion und Logistik 2025 N2 - This paper presents the architecture and functionality of a simulation-based Digital Twin designed to support decision-making in the control of internal transport systems. The developed Digital Twin leverages a wide range of data from operational information systems to predict future system loads. Specific methods for forecasting transport orders have been developed. An integrated simulation framework enables analysis of potential control decisions, such as resource allocation or the timing of order releases. The simulation results are used for multi-criteria evaluation of the available options for preventive action, thus, providing users with concrete recommendations to support their operational decision-making processes. KW - Digital Twin, Simulation, Logistics Y1 - 2025 SN - 978-3-86780-806-4 U6 - https://doi.org/10.25368/2025.280 SP - 47-1 EP - 47-11 PB - Technische Universität Dresden, Professur für Technische Logistik CY - Dresden ER - TY - CHAP A1 - Galka, Stefan A1 - Weigert, Alexander T1 - Petri Net Structures for Automated Model Generation through Process Descriptions T2 - IFAC Papers OnLine N2 - Creating simulation models and running experiments requires expertise and significant effort. Modelling complex production systems by using Petri Nets, which have a simple formalism, leads to considerable modelling effort. To reduce the workload required, fundamental processes within a production system must be analyzed and represented as generic Petri Net structures to enable their automatic generation. These structures can serve as modular building blocks to construct arbitrarily complex systems. The broader objective is to enable the automatic generation of such, based on process descriptions within a simulation framework. Built on these findings, the necessary information for developing a specialized formal process description is derived, enabling the automated generation of Petri Net simulation models for production systems. KW - Digital Twin, Simulation, Logistics Y1 - 2025 U6 - https://doi.org/10.1016/j.ifacol.2025.09.093 VL - 59 IS - 10 SP - 542 EP - 547 PB - Elsevier ER - TY - CHAP A1 - Galka, Stefan T1 - Integration and usage of simulation-based digital twins in internal logistics systems T2 - IFAC Papers OnLine N2 - This paper presents the workflows of Digital Twins in practice, with reference to three case studies. The objective is to present the processing of data and information flow. The most essential requirements for the design of a Digital Twin are synthesized from the case studies and a layer model is presented, which was developed based on the three case studies. The model consists of four functional layers and an overarching data- and workflow-management-backbone. A front-end layer is proposed for communication with the end user. KW - Digital Twin, Simulation, Logistics Y1 - 2025 U6 - https://doi.org/10.1016/j.ifacol.2025.09.152 VL - 59 IS - 10 SP - 897 EP - 902 PB - Elsevier ER - TY - JOUR A1 - Ginster, Vinzenz A1 - Weigert, Alexander A1 - Heym, Maximilian Klaus A1 - Beier, Christoph Jürgen Anton A1 - Schiebahn, Alexander A1 - Galka, Stefan T1 - Factory simulation of adhesive bonding processes considering pot-life-induced waste JF - Journal of Advanced Joining Processes N2 - The simulation of production systems in the planning phase is an established tool for evaluating system performance under dynamic conditions (Da Silva et al., 2018). When planning a production system that includes time-critical processes such as adhesive bonding, exceeding time constraints (e.g., excessive lead times relative to the adhesive pot-life) can lead to product rejection and scrap. These risks should be analyzed by means of simulation, as it enables the consideration of stochastic effects such as random machine breakdowns, which significantly influence product lead times. This study focuses on the production of adhesively bonded electrolyzer-cells. Due to the cell design, several handling and stacking operations must be carried out between adhesive application and final joining, so that immediate joining is not feasible and pot-life-induced scrap becomes a critical risk factor. We therefore conducted an exploratory investigation that combines experimental pot-life characterization with discrete-event simulation of a planned electrolyzer-cell production system. A two-component epoxy adhesive was characterized using differential scanning calorimetry with kinetic analysis, rotational rheometry, and 90° peel tests on application-representative joints. Based on these tests, an application-specific pot-life was derived and implemented as a time-dependent quality criterion in the discrete-event simulation model. A full-factorial simulation study with varied buffer size and mean time to repair at a station availability of 98 % was carried out. The results demonstrated a pronounced trade-off between throughput and pot-life-induced waste and identified a buffer capacity of one and short repair times as the most favorable configuration. Extending pot-life due to different processing temperatures substantially reduced scrap, highlighting the benefit of integrating curing kinetics and dynamic simulation in early-stage production system design for time-critical adhesive processes. KW - Digital Twin, Simulation, Logistics Y1 - 2026 U6 - https://doi.org/10.1016/j.jajp.2026.100375 SN - 2666-3309 VL - 13 PB - Elsevier ER - TY - CHAP A1 - Galka, Stefan A1 - Meißner, Sebastian T1 - Simulation-Based Digital Twins for Internal Transport Systems T2 - Procedia Computer Science N2 - The increasing complexity of internal transport systems in industrial applications poses significant challenges for operational decision-making. This paper presents a simulation-based Digital Twin framework developed within the research project TwinTraSys to support the control of such systems. The framework is specifically tailored to the constraints of real-world IT infrastructures, requiring minimal transaction data, while enabling predictive analysis and dynamic scenario evaluation. It consists of a modular architecture divided into four core components: data provision, data preparation, simulation, and decision support. A dedicated simulation framework enables the automated generation of structural models and the integration of real-world operational control systems. The proposed approach has been validated in industrial settings and has demonstrated its ability to support resource planning and transport resource allocation through simulation-based experimentation and multi-criteria evaluation. This paper contributes to the practical advancement of Digital Twin applications in intralogistics by bridging the gap between theoretical models and real-world constraints. KW - Digital Twin KW - Intralogistics KW - Logistics KW - Operational Control KW - Simulation KW - Simulation-based Decision Support Y1 - 2025 U6 - https://doi.org/10.1016/j.procs.2025.12.016 N1 - Corresponding author der OTH Regensburg: Stefan Galka VL - 274 SP - 161 EP - 170 PB - Elsevier ER - TY - CHAP A1 - Galka, Stefan A1 - Wappler, Mona T1 - INTEGRATION OF CASH FLOW MANAGEMENT AND FURTHER ASPECTS OF THE SUPPLY CHAIN MANAGEMENT IN PRODUCTION SYSTEM DESIGN T2 - IFAC-PapersOnLine N2 - One major goal of production system design is to decide on space requirements in the plant. In this phase, detailed information about the supply chain network (e.g. which suppliers deliver which parts) is often unavailable. Nevertheless, typical decisions in supply chain management, like the definition of replenishment processes and quantities or make-or-buy decisions, impact space requirements and the capital investment in raw materials and should therefore be considered in factory and production planning. This research article proposes a simulation approach for a production simulation in which raw material replenishment is integrated to evaluate the capital investment and space requirements for raw materials. KW - Supply chain management KW - nventory control KW - Logistics in manufacturing KW - Factory planning Y1 - 2023 U6 - https://doi.org/10.1016/j.ifacol.2023.10.1687 SN - 2405-8963 VL - 56 IS - 2 SP - 947 EP - 952 PB - International Federation of Automatic Control. Published by Elsevier Ltd. CY - Yokohama ER -