TY - CHAP A1 - Schmid, Florian A1 - Wild, Tobias A1 - Schneidewind, Jan A1 - Vogl, Tobias A1 - Schuhegger, Lukas A1 - Galka, Stefan T1 - Simulation Based Approach for Reconfiguration and Ramp up Scenario Analysis in Factory Planning T2 - Proceedings of the 2022 Winter Simulation Conference (WSG), 11-14 Dec. 2022, Singapore N2 - Structural changes in production entail a potential economic risk for manufacturing companies. It is necessary to identify a suitable strategy for the reconfiguration process and to continue to meet the demand during the change in the factory structure and ramp-up phase. A simulation offers the possibility to analyze different ramp-up scenarios for the factory structure and to select a suitable concept for the reconfiguration process. A discrete event simulation approach is presented that can be used to evaluate variants of structural changes and serves as a basis for deciding on a reconfiguration strategy. This approach is demonstrated using a specific production step of a plant producing hydrogen electrolyzers, the results and generalized conclusions are discussed. KW - Simulation KW - Production KW - Ramp up Y1 - 2022 SN - 978-1-6654-7661-4 U6 - https://doi.org/10.1109/WSC57314.2022.10015310 SP - 2842 EP - 2852 PB - IEEE ER - TY - CHAP A1 - Galka, Stefan A1 - Schuhegger, Lukas ED - Feng, B. ED - Pedrielli, G. ED - Peng, Y. ED - Shashaani, S. ED - Song, E. ED - Corlu, C.G. ED - Lee, L.H. ED - Chew, E.P. ED - Roeder, T. ED - Lendermann, P. T1 - Integration of Discrete-event Simulation in the Planning of a Hydrogen Electrolyzer Production Facility T2 - Proceedings of the 2022 Winter Simulation Conference (WSC), 11-14 Dec. 2022, Singapore N2 - In the context of production and factory planning, the expansion of the factory must already be taken into account during initial planning. This results in an increase in planning complexity, as the involved planners have to know the expansion stages of the factory in the different time periods and have to evaluate concept modifications across all time periods. This paper presents an idea for a planning tool, which takes expansion stages into consideration. The data model contains all relevant information to generate a simulation model of the factory in an almost automated way. The aim is to enable factory planners to quickly investigate concept changes with the help of simulation, for example, to identify bottlenecks. KW - Simulation KW - Production KW - Digital Twin Y1 - 2022 UR - https://informs-sim.org/wsc22papers/pos114.pdf PB - IEEE CY - Singapore ER - TY - CHAP A1 - Ulbrich, Alexander A1 - Galka, Stefan A1 - Günthner, Willibald A. T1 - Secure planning of order picking systems with the aid of simulation T2 - Proceedings of th 43rd Hawaii International Conference on System Sciences (HICSS), 5-8 Jan. 2010, Koloa, Kauai, Hawaii N2 - Planning a new logistics center is a quite difficult job. Depending on the requirements there are a great number of possible design versions. The planner has to consider not only the present but also the future requirements. Up to now, the planner decides on the basis of experience which system will perform the requested services best. This paper illustrates the redesign of a new order-picking system in industry supported by a simulation tool of our institute designed especially for the rough planning. With the described project the road capability of the applied simulation concept is underlined. Several versions based on the requirements were investigated and evaluated. Key figures are calculated and a recommendation depending on performance and arising expenses is given. Y1 - 2010 SN - 978-0-7695-3869-3 SN - 076953869X U6 - https://doi.org/10.1109/HICSS.2010.326 SN - 1530-1605 SP - 1 EP - 7 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Schneidewind, Jan A1 - Galka, Stefan T1 - Interactive reinforcement learning-based factory layout planning T2 - 13th Conference on Learning Factories (CLF 2023), 9-11 May 2023, Reutlingen, Germany N2 - Due to the complexity and the number of factors involved in factory layout planning, computers were identified as an efficient tool to support the process. However, so far no method for computer-aided layout planning has gained wide acceptance in practical application. One reason for this is that in present approaches either the user or the computer designs the layout, neglecting either the qualitative or the quantitative goals. To bridge this gap, this article introduces a concept for human-computer-integration based on evaluative feedback and inverse reinforcement learning. A key element of the concept is the interactive planning process in which user and computer alternately design and improve the layout until a satisfactory layout is found. The user evaluates the layouts according to qualitative criteria, adjusts them intuitively and specifies objectives and restrictions in an explorative way. The computer on the other hand – in form of a reinforcement algorithm – generates possible layouts and incorporates the user’s feedback into its policy. This synergy is expected to generate better results than an expert or an algorithm alone could. Furthermore, in the context of learning factories, it encourages critical thinking and allows students to develop a deeper understanding of the factors that contribute to efficient manufacturing processes. Both an architecture for the implementation is proposed and the requirements for the user interface are specified. KW - factory planning KW - facility layout problem KW - machine learning KW - optimization KW - inverse reinforcement learning Y1 - 2023 UR - https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4469300 PB - SSRN ER - TY - GEN A1 - Galka, Stefan T1 - Podcast "Irgendwas mit Logistik", Folge 82: Automatisierungstechnik richtig und fair abnehmen N2 - Professoren wird häufig unterstellt Theoretiker zu sein. Das haben wir zum Anlass genommen, um gemeinsam mit Stefan Galka, Professor an der OTH Regensburg, im Irgendwas mit Logistik Podcast über ein ziemlich praktisches Thema zu sprechen - Inbetriebnahmen von Automatisierungstechnik. Stefan, Jens und Thomas zäumen das Pferd von hinten auf und versuchen zu klären, wer welche Verantwortungen und (ggf. verdeckten) Interessen bei der Realisierung von technischen Gewerken hat, welche Richtlinien bei der Durchführung helfen können und definieren gemeinsam, wie die Inbetriebnahme zum Erfolg wird. Y1 - 2021 UR - https://irgendwas-mit-logistik.podigee.io/82-automatisierungstechnik-richtig-und-fair-abnehmen-gast-stefan-galka-von-der-oth-regensburg ET - veröffentlicht am 05.04.2021 ER - TY - CHAP A1 - Galka, Stefan A1 - Scherbarth, Christoph ED - Franke, Jörg ED - Schuderer, Peter T1 - Simulationsbasierte Untersuchung der Grenzproduktivität von Robotern in einem AutoStore-Lagersystem T2 - Simulation in Produktion und Logistik 2021 : Erlangen, 15.-17. September 2021 Y1 - 2021 SN - 978-3-7369-7479-1 SP - 197 EP - 206 PB - Cuvillier Verlag CY - Göttingen ER - TY - BOOK A1 - Galka, Stefan T1 - AutoStore - was Nutzer über das System berichten können BT - Ergebnisse einer Online-Umfrage KW - Kleinteil KW - Lager KW - Intralogistik KW - Umfrage Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-6463 SN - 978-3-9818209-9-7 CY - Regensburg ER - TY - CHAP A1 - Strassburger, Steffen A1 - Galka, Stefan A1 - Lang, Sebastian A1 - Reggelin, Tobias ED - Bui, Tung T1 - Introduction to the Minitrack on Simulation Modeling, Artificial Intelligence and Digital Twins for Decision Making in Production and Logistics T2 - Proceedings of the 58th Hawaii International Conference on System Sciences, January 7-10, 2025, Honolulu, Hawaii N2 - The minitrack contains contributions with a focus on simulation modeling and digital twins and decision making in the context of Industry 4.0. The use of simulation models and digital twins is manifold, from planning to virtual commission and real-time operational decision support. Cyber-physical systems integrate the real world and the virtual world to enable decision making in the age of Industry 4.0. For example, customer decisions and supply disruptions which directly influence manufacturing and logistics systems require immediate decisions. Thus, models must have the capability to support decision making in manufacturing as well as in internal and external logistics in real-time. Methods include discrete-event simulation, discrete-rate simulation, hybrid simulation, system dynamics simulation, the combination of simulation modeling with machine learning or optimization heuristics, prescriptive analytics, and adaptive systems. Furthermore, this minitrack addresses simulation education and simulation models and digital twins used for education and training in manufacturing and logistics. Y1 - 2025 SN - 978-0-9981331-8-8 U6 - https://doi.org/10.24251/HICSS.2025.205 SP - 1677 EP - 1678 PB - University of Hawaii at Manoa ER - TY - GEN A1 - Wild, Tobias A1 - Galka, Stefan A1 - Wappler, Mona A1 - Xing, Lu ED - Potter, A. ED - Pawar, K. S. ED - O’Reilly, S. ED - Jimo, A. T1 - Integrating supply chain aspects into factory planning, a simulation approach T2 - The journey to sustainable supply chains: proceedings of the 26th International Symposium on Logistics (ISL 2022), 10-13th July 2022, Cork, Ireland N2 - One major goal of green-field factory planning 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 in the factory and should therefore be considered in the factory planning. This research article proposes a simulation approach for a factory simulation in which raw material replenishment is integrated to evaluate the space requirements for raw materials. KW - factory planning KW - supply chain management KW - replenishment strategies KW - space requirements KW - discrete event simulation Y1 - 2022 UR - https://isl21.org/wp-content/uploads/2022/07/ISL_2022_Proceedings.pdf SN - 978-0-85358-350-9 PB - Nottingham University Business School, UK CY - Nottingham, UK ER - TY - CHAP A1 - Galka, Stefan T1 - Untersuchung von Auftragsfreigabestrategien für mehrzonige Kommissioniersysteme im Online-Lebensmittelhandel T2 - ASIM SST 2022 Proceedings Langbeiträge, 26. ASIM Symposium Simulationstechnik: 25.07.-27.07.2022, TU Wien N2 - This paper briefly presents the challenges for order control and release of multi-zone order picking systems. On the one hand, the order control must ensure that all orders are processed on time, and on the other hand, the space requirements (buffer) and the utilisation of the zones must be considered. Within the framework of a case study, different strategies for order release were developed. The paper shortly describes the ideas of the strategies and presents results of a case-based simulative evaluation of the strategies. The findings of the simulation study are the basis for the development of a digital twin for the operational control of multi-zone picking systems. KW - Simulation KW - Kommissionierung KW - Simulation KW - Logistik KW - Planung Y1 - 2022 SN - 978-3-901608-97-1 U6 - https://doi.org/10.11128/arep.20.a2021 VL - 2022 SP - 23 EP - 30 PB - ARGESIM Verlag CY - Wien ER - TY - CHAP A1 - Galka, Stefan A1 - Günthner, Willibald A. A1 - Ulbrich, Alexander T1 - Planning of order-picking-systems with support of discrete simulation T2 - Logistics and Supply Chain Management: Deutsch-Russische Perspektiven. Proceedings of the 5th German-Russian Logistics Workshop (DR-LOG10) Y1 - 2010 ER - TY - JOUR A1 - Galka, Stefan A1 - Klenk, Eva Marianne A1 - Günthner, Willibald A. T1 - Einfluss von Artikeleigenschaften auf die Entnahmezeit in Kommissioniersystemen JF - Logistics Journal / Proceedings N2 - Das Kommissionieren zählt zu den arbeitsintensivsten Aufgaben in der Logistik. Aus diesem Grund ist es wichtig, möglichst genau die erwarteten Prozesszeiten für diese Aufgabe zu bestimmen. Ein verbreiteter Ansatz für die Bestimmung von Prozesszeiten für manuelle Tätigkeiten beim Kommissionieren ist die Methods-Time-Measurement (MTM). Um eine Vorgabezeit mittels MTM zu bestimmen, müssen Einflussfaktoren spezifiziert werden. Dieser Beitrag zeigt anhand der Greifzeit auf, wie diese Einfluss-faktoren auf Grundlage von Artikelstammdaten bestimmt werden können. Weiterhin wird der Unterschied zwischen einer für jeden Artikel individuell bestimmten Greifzeit und der Greifzeit basierend auf repräsentativen Eigenschaften von Artikelgruppen verglichen. Wesentlich wird dabei die mittels MTM bestimmte Greifzeit durch das Gewicht und die Abmessungen (Sperrigkeit) beeinflusst. T2 - Impact of items characteristics on picking time in order picking systems systems Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0009-14-44540 SN - 2192-9084 PB - WGTL, Wissenschaftliche Gesellschaft für Technische Logistik e. V. CY - Stuttgart ; Dortmund ER - TY - JOUR A1 - Galka, Stefan A1 - Rammelmeier, Tobias A1 - Günthner, Willibald A. T1 - Fehlervermeidung in der kommissionierung JF - Logistics Journal N2 - Manuelle Kommissioniersysteme sind aufgrund ihrer Flexibilität weit verbreitet, jedoch treten bei diesen auch vermehrt Kommissionierfehler auf, die weitreichende Folgen haben können. Deshalb werden zu Beginn des Beitrags die Auswirkungen und Ursachen von Kommissionierfehlern betrachtet. Der Fokus des Beitrags liegt auf der Darlegung von Möglichkeiten zur Fehlervermeidung. Dabei wird ein ganzheitlicher Ansatz verfolgt, der Maßnahmen aus den Handlungsfeldern Technik, Prozess, Organisation und Motivation umfasst. Als Ausblick auf zukünftige technische Hilfsmittel zur Fehlervermeidung wird das Augmented-Reality-unterstützte System Pick-by-Vision aus der Forschung vorgestellt, das wesentliche Vorteile existierender Techniken der Informationsbereitstellung vereinigt. T2 - Error prevention in manual order picking KW - Kommissionierfehlervermeidung KW - Kommissionierung KW - Pick-by-Vision KW - augmented reality KW - order picking KW - picking error Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0009-14-34494 SN - 2192-9084 N1 - https://www.logistics-journal.de/proceedings/2012/3449 Jedermann darf dieses Werk unter den Bedingungen der freien Digital Peer Publishing Lizenz elektronisch über­mitteln und zum Download bereit­stellen. Der Lizenztext ist im Internet unter der Adresse http://www.dipp.nrw.de/lizenzen/dppl/fdppl/f-DPPL_v1_de_11-2004.html abrufbar. SP - 1 EP - 8 PB - WGTL, Wissenschaftliche Gesellschaft für Technische Logistik e. V. CY - Stuttgart ; Dortmund ER - TY - CHAP A1 - Reggelin, Tobias A1 - Galka, Stefan A1 - Ivanov, Dmitry A1 - Lang, Sebastian T1 - Introduction to the Minitrack on Modeling and Decision Making in Manufacturing and Logistics in the Age of Industry 4.0 T2 - Proceedings of the 54th Hawaii International Conference on System Sciences (HICSS): 2021 Hawaii, USA N2 - The minitrack contains contributions with a focus on modeling and decision making in manufacturing and logistics in the context of Industry 4.0. Cyber-physical systems integrate the real world and the virtual world. For example, customer decisions and supply disruptions which directly influence manufacturing and logistics systems require immediate decisions in terms of planning and controlling the manufacturing and logistics systems. In order to immediately respond to these dynamics, models must have the capability to support decision making in manufacturing as well as in internal and external logistics in real-time. Two of the Mintrack papers describe concepts and models for digital twins. One paper provides an adaptive scheduling framework for solving multi-objective hybrid flow shop scheduling problems and one paper investigates matrix production systems and with their requirements and impacts on logistics planning. Y1 - 2021 SN - 978-0-9981331-4-0 U6 - https://doi.org/10.24251/HICSS.2021.198 SP - 1643 EP - 1644 PB - University of Hawai'i at Manoa Hamilton Library CY - Honolulu, HI ER - TY - CHAP A1 - Haimerl, Simon A1 - Tschernitz, Christoph A1 - Schiller, Tobias A1 - Weig, Christoph A1 - Briem, Ulrich A1 - Galka, Stefan T1 - Development of a Simulation Framework for Urban Ropeway Systems and Analysis of the Planned Ropeway Network in Regensburg, Germany T2 - Proceedings of the 2022 Winter Simulation Conference (WSC), 11-14 Dec. 2022, Singapore N2 - To evaluate the performance of a ropeway in an urban environment, simulations of the dynamic passenger transport characteristics are required. Therefore, a modular simulation model for urban ropeway networks was developed, which can be flexibly adapted to any city and passenger volume. This simulation model was used to analyze the ropeway network concept of the German city Regensburg and to determine the expected operating conditions. The passenger volume, different types of persons, their occurrence probability and their destination distribution is depending on the location and daytime and can be defined for each individual station. In an initial analysis, the number of passengers currently occurring in bus traffic were projected onto the ropeway network. To enable climate-friendly and efficient operation, different strategies were developed to significantly reduce the number of gondolas. The best fitting strategies resulted in significant cost savings while passenger comfort, as represented by queue time, remained unchanged. KW - Simulation KW - urban mobility KW - ropeway Y1 - 2022 SN - 978-1-6654-7661-4 U6 - https://doi.org/10.1109/WSC57314.2022.10015510 SP - 1413 EP - 1424 PB - IEEE ER - TY - JOUR A1 - Klenk, Eva Marianne A1 - Galka, Stefan T1 - Analysis of real-time tour building and scheduling strategies for in-plant milk-run systems with volatile transportation demand JF - IFAC - PapersOnLine N2 - In modern manufacturing systems, milk run (MR) systems represent route-based, cyclic material-handling systems that are used widely and enable frequent deliveries of containerized parts in small lot sizes from a central storage area to multiple points of use on the factory floor. Usually, deliveries take place at predetermined, constant time intervals. As in real-world MR systems, the number of containers to deliver in each interval varies in the short term, peaks in the number of deliveries may lead to capacity bottlenecks and late deliveries. In this paper, we develop three alternative strategies to determine starting times of MR cycles in real-time based on the current number of delivery orders in the system aiming to better handle variations in the number of orders. We evaluate the three strategies for different system load scenarios with respect to delivery service levels, order lead times, systems utilization and necessary number of MR trains using a discrete-event simulation model. KW - Control algorithms KW - Logistics KW - Material handling KW - Milk-run systems KW - Production systems KW - Real-time decision making KW - Transportation control Y1 - 2019 U6 - https://doi.org/10.1016/j.ifacol.2019.11.517 VL - 52 IS - 13 SP - 2110 EP - 2115 PB - Elsevier ER - TY - JOUR A1 - Galka, Stefan A1 - Wappler, Mona T1 - Integration of cash flow management and further aspects of the supply chain management in production system design JF - 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. Therefore, it should 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. Y1 - 2023 U6 - https://doi.org/10.1016/j.ifacol.2023.10.1687 VL - 56 IS - 2 SP - 947 EP - 952 PB - IFAC / Elsevier ER - TY - BOOK A1 - Galka, Stefan A1 - Fottner, Johannes A1 - Klenk, Eva Marianne A1 - Habenicht, Sebastian A1 - Meinhardt, Ingolf A1 - Schmidt, Thorsten T1 - Planung von innerbetrieblichen Transportsystemen BT - Fahrzeugsysteme N2 - Dieses Buch beschreibt bewährte, praxistaugliche Methoden zur Planung innerbetrieblicher Transportsysteme. Der Fokus liegt auf den wesentlichen Systemen und Förderfahrzeugen, die derzeit in der Industrie eingesetzt werden: Gabelstapler, fahrerlose Transportfahrzeuge, Routenzüge und Elektrohängebahnen. Neben einer Beschreibung relevanter Systemelemente und Gestaltungsmöglichkeiten liefert das Buch Empfehlungen zur Auswahl eines geeigneten Systems entsprechend der individuellen Anforderungen. Planungsschritte von der Erhebung von Plandaten bis zur Umsetzung werden vorgestellt. Methoden, die bei Planungsentscheidungen wie der Bestimmung der Anzahl benötigter Fahrzeuge helfen, sind detailliert beschrieben; ihre Anwendung wird anhand von Fallbeispielen demonstriert. Do's and Dont’s, basierend auf Erfahrungen von Praktikern und Wissenschaftlern, tragen dazu bei, Planungsfehler zu vermeiden. Das Buch wendet sich an Planer und Betreiber derartiger Systeme, Studierende einschlägiger Studienfächer bekommen einen vertieften Einblick in die Umsetzung der Methoden. KW - Intralogistik KW - Materialflussplanung KW - Flurförderzeug KW - Logistik Y1 - 2022 SN - 978-3-662-63972-6 U6 - https://doi.org/10.1007/978-3-662-63973-3 VL - 2022 PB - Springer Vieweg CY - Berlin, Heidelberg ET - 1. Auflage ER - TY - CHAP A1 - Galka, Stefan A1 - Schmid, Florian ED - Schlund, Sebastian ED - Ansari, Fazel T1 - Initialization of Simulation-Based Digital Twins for Internal Transport Systems T2 - IFAC-PapersOnLine N2 - To support operational decisions using simulation-based digital twins, it is crucial to synchronize the simulation model quickly and accurately with the load state in the real system. This minimizes the typical transient behavior of material flow simulations to a short period of time. This paper presents a concept for initializing a simulation model using the example of a distribution center that uses SAP EWM as a warehouse management system. As part of a study, the influence of the presented initialization concept on the simulation models’ transient behavior is investigated. The simulation model used as a reference is in an ‘empty’ load state at the beginning of the simulation. The study results indicate that the proposed approach can significantly shorten the transient behavior. KW - Discrete event simulation KW - Digital Twins KW - Logistic KW - Modell Initialization Y1 - 2024 U6 - https://doi.org/10.1016/j.ifacol.2024.09.127 SN - 2405-8963 VL - 58 IS - 19 SP - 1084 EP - 1089 CY - Wien ER - TY - CHAP A1 - Galka, Stefan T1 - Reducing Transient Behavior in Simulation-Based Digital Twins: A Novel Initialization Approach for Order Picking Systems T2 - 2024 Winter Simulation Conference (WSC), 15-18 December 2024, Orlando, FL, USA N2 - In the context of facilitating operational decision-making through simulation-based digital twins, precise and expeditious synchronization of simulation models with real-system load states is paramount. Such synchronization serves to attenuate the typical transient behavior observed in material flow simulation, confining it to a brief temporal window. This paper delineates a novel conceptual framework for initializing simulation models, illustrated through an exemplar of an order picking system integrated with SAP Extended Warehouse Management as its warehouse and operation management system. Through empirical inquiry, the ramifications of the proposed initialization framework on simulation model transient behavior are scrutinized. Notably, the reference simulation model commences in a state of ‘empty’ load. The findings of this study evince that the proposed approach yields a significant improvement in transient behavior. Y1 - 2024 SN - 979-8-3315-3420-2 U6 - https://doi.org/10.1109/WSC63780.2024.10838961 SP - 1434 EP - 1445 PB - IEEE ER - TY - CHAP A1 - Schuhegger, Lukas A1 - Armbruster, Thomas A1 - Galka, Stefan T1 - Factory Data Model for Planning Variant Sequences, Expansion Stages and Reconfigurations T2 - IFAC-PapersOnLine N2 - A factory has to adapt to a future production program and increasing volumes. The planning of new factories must therefore already take expansion stages and reconfigurations into account. This leads to an increase in the complexity of planning, as different variants have to be planned and put into a chronologically reasonable and cost-optimized sequence. A factory data model that covers expansion stages manages the planning data amount and reduces complexity. Based on existing models from the literature, a factory data model was developed and modeled in the Unified Modeling Language standard. The factory data model shows which classes are interdependent and how planning results are stored reusable for other variants. An example is used to explain the developed factory data model and highlighting its advantages. The aim is to enable factory planners to document variant sequences and expansion stages in a comprehensible way, which supports the interdisciplinarity of factory planning projects. Y1 - 2023 U6 - https://doi.org/10.1016/j.ifacol.2023.10.1573 VL - 56 IS - 2 SP - 227 EP - 232 PB - IFAC / Elsevier ER - TY - CHAP A1 - Rolf, Benjamin A1 - Reggelin, Tobias A1 - Lang, Sebastian A1 - Galka, Stefan T1 - Developing a Decision Support System for Integrated Decision-Making in Purchasing and Scheduling under Lead Time Uncertainty T2 - Proceedings of the 55th Hawaii International Conference on System Sciences (HICSS55): January 3-7, 2022, Maui, Hawaii, USA N2 - Decision-making in supply chain management is complex because of the relations between planning tasks from different stages and planning levels. Uncertainties such as unpredictable supplier lead times and supply chain disruptions further complicate decision-making. Considering the case study of a company in printed circuit board assembly, a three-level concept is proposed that includes a decision support system. The global single-source supply network is characterized by highly variable lead times. Hence, the company maintains high inventory levels to prevent running out of stock. The decision support system considers the purchasing and scheduling decision problems in an integrated way. The prototypical implementation of the purchasing algorithm uses a genetic algorithm that recommends reorder days and order quantities using a simulation model. In addition, it evaluates the risks of the recommended solution by calculating the probability of stockouts for each order cycle. KW - decision support system KW - simulation KW - supply chain optimization, KW - purchasing KW - cyber-physical system KW - Industry 4.0 Y1 - 2022 U6 - https://doi.org/10.24251/HICSS.2022.247 VL - 2022 SP - 1964 EP - 1973 ER - TY - CHAP A1 - Kauke, Dirk A1 - Fottner, Johannes A1 - Galka, Stefan T1 - Digital Twins in Order Picking Systems for Operational Decision Support T2 - Proceedings of the 54th Hawaii International Conference on System Sciences (HICSS): 2021 Hawaii, USA N2 - Digital twins are arousing great interest in both science and industry. There are a large number of papers that demonstrate and evaluate the potential of Digital Twins in different application areas. However, it must be noted that there is still no uniform definition of Digital Twins. This paper first examines the concept of Digital Twins and highlight how they differ in level, compared with other digital models. The focus of this paper lies in the conceptual development of a digital twin in order picking systems. The described approach in the paper aims at supporting the operational control in order picking systems. Both the architectural structure and the functions, e.g. the simulation, are described in detail. Overall, this thesis shows the benefits of Digital Twins. However, some functional extensions are still needed before the full potential can be achieved. Y1 - 2021 SN - 978-0-9981331-4-0 U6 - https://doi.org/10.24251/HICSS.2021.200 SP - 1655 EP - 1664 PB - University of Hawai'i at Manoa Hamilton Library CY - Honolulu, HI ER - TY - CHAP A1 - Fottner, Johannes A1 - Galka, Stefan A1 - Habenicht, Sebastian A1 - Klenk, Eva Marianne A1 - Meinhardt, Ingolf A1 - Schmidt, Thorsten ED - Fottner, Johannes ED - Galka, Stefan ED - Habenicht, Sebastian ED - Klenk, Eva Marianne ED - Meinhardt, Ingolf ED - Schmidt, Thorsten T1 - Gestaltungsprinzipien für innerbetriebliche Fahrzeugsysteme T2 - Planung von innerbetrieblichen Transportsystemen N2 - Bei der Planung von innerbetrieblichen Transportsystemen besteht die Aufgabe darin, Transportsysteme so zu gestalten und zu dimensionieren, dass Unternehmensziele unter Berücksichtigung gegebener Rahmenbedingungen möglichst ideal erfüllt werden. Ob ein geplantes System schlussendlich den an die Lösung gestellten Zielen gerecht wird und wie gut es "funktioniert", ergibt sich aus dem Zusammenspiel der in Kap. 2 beschriebenen Systemelemente. Da sich Ziele und Rahmenbedingungen je nach konkretem Einsatzfall unterscheiden und sich daraus unterschiedliche Anforderungen an Transportsysteme ergeben, müssen die Systembausteine in geeigneter Kombination ausgestaltet und dimensioniert werden. Ansätze dafür werden in Kap. 5 ausführlich vorgestellt. Y1 - 2022 SN - 978-3-662-63972-6 U6 - https://doi.org/10.1007/978-3-662-63973-3_3 SP - 67 EP - 76 PB - Springer CY - Berlin, Heidelberg ET - First Online: 07 May 2022 ER - TY - BOOK A1 - Lieb, Christian A1 - Klenk, Eva Marianne A1 - Galka, Stefan A1 - Keuntje, Christopher T1 - Einsatz von Routenzugsystemen zur Produktionsversorgung : Studie zu Planung Steuerung und Betrieb KW - Effizienz KW - Produktion KW - Routenzug Y1 - 2017 SN - 978-3-941702-79-0 PB - fml - Lehrstuhl für Fördertechnik Materialfluß Logistik Technische Universität München CY - Garching b. München ER - TY - JOUR A1 - Galka, Stefan T1 - Tipps zur Absicherung der Investitionsentscheidung in ein Autostore-System JF - Fördern + Heben Y1 - 2021 UR - https://digital.foerdern-und-heben.de/f-h-fordern-und-heben-1-2-2021/65265320 IS - 1-2 SP - 12 EP - 14 PB - Vereinigte Fachverlage GmbH CY - Mainz ER - TY - JOUR A1 - Galka, Stefan A1 - Follath, Alexander A1 - Bross, Florian ED - Bauer, Wilhelm ED - Volk, Wolfram ED - Zäh, Michael T1 - Vorgehensmodell zur Erstellung Digitaler Zwillinge für Produktion und Logistik JF - Zeitschrift für wirtschaftlichen Fabrikbetrieb N2 - Der Digitale Zwilling (DZ) ist ein wichtiger Bestandteil der Industrie 4.0 und ermöglicht Anwendungen wie Predictive Maintenance, virtuelles Prototyping oder die Steuerung von Produktions- und Logistikprozessen. Herausforderungen bei der Entwicklung des Digitalen Zwillings entstehen durch fehlende Struktur und Standards. Mit diesem Beitrag soll ein Vorgehensmodell für die Erstellung eines Digitalen Zwillings im Bereich der Produktion und Logistik aufgezeigt werden. Das Vorgehensmodell hilft bei der Einordnung, für welche Anwendungsfälle ein Digitaler Zwilling entwickelt werden kann, welche Schritte bei einer Umsetzung erfolgen müssen, und gibt einen Überblick über die Voraussetzungen und Komplexität bei der Entwicklung. Das zentrale Element bildet dabei die zielgerichtete Aufbereitung und Analyse der zugrunde liegenden Daten mittels des in der Industrie etablierten Vorgehensmodell CRISP-DM. KW - Digitale Zwillinge KW - Simulation KW - Logistik KW - Produktion Y1 - 2022 U6 - https://doi.org/10.1515/zwf-2022-1127 VL - 117 IS - 11 SP - 691 EP - 696 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Galka, Stefan T1 - Operating strategies for in-plant milk-run systems JF - IFAC-Papers OnLine N2 - In-plant milk-run systems are transportation systems, where materials are delivered from a central storage area to several points of use on defined routes and in short intervals. Milk-run systems generally enable frequent deliveries in smaller lot sizes with short lead times and low inventory at the points of use. In real milk-run systems, the number of deliveries per interval varies due to, e.g., variations in the production program. To enable efficient and stable milk-run system operations, these systems therefore must be able to cope with peaks in the number of deliveries. We develop different strategies for handling these delivery peaks and evaluate them with respect to delivery cost, lead time and service level using real material consumption data from two large companies from the automotive industry. KW - Automobile industry KW - Control algorithms KW - Lean manufacturing KW - Logistics KW - Mulk-run systems KW - Production systems KW - Transportation control Y1 - 2015 U6 - https://doi.org/10.1016/j.ifacol.2015.06.361 VL - 48 IS - 3 SP - 1882 EP - 1887 PB - Elsevier CY - Frankfurt ER - TY - CHAP A1 - Galka, Stefan A1 - Klenk, Eva Marianne A1 - Günthner, Willibald A. T1 - Planning of production supermarkets for production supply T2 - Proceedings of 2013 IEEE International Conference on Service Operations and Logistics, and Informatics, 28-30 July 2013, Dongguan, China N2 - Production supermarkets are a system to ensure high-frequency, demand-oriented, in-plant production supply with low lot sizes. The paper presents methods to design and dimension these systems using qualitative design criteria and quantitative approaches based on well-known analytical methods for conventional order picking systems. The methods help to design layout, provision type and path strategy and to derive space consumption and the number of supermarket employees required to fulfill a defined demand. Y1 - 2013 SN - 978-1-4799-0530-0 U6 - https://doi.org/10.1109/SOLI.2013.6611458 SP - 456 EP - 461 PB - IEEE CY - Piscataway, NJ ER - TY - JOUR A1 - Galka, Stefan A1 - Klenk, Eva Marianne A1 - Günthner, Willibald A. T1 - Potenziale einer flexiblen Routenzugsteuerung: Strategien zum besseren Umgang mit schwankenden Transportbedarfen JF - Zeitschrift fuer Wirtschaftlichen Fabrikbetrieb : ZWF T2 - Potentials of a in-plant milk run control Y1 - 2015 U6 - https://doi.org/10.3139/104.111444 SN - 2511-0896 SN - 0947-0085 VL - 110 IS - 12 SP - 805 EP - 809 PB - de Gruyter CY - Berlin ER - TY - CHAP A1 - Galka, Stefan ED - Britzke, Bernd T1 - Planung und Auswahl von Kommissioniersystemen T2 - MTM in einer globalisierten Wirtschaft : Arbeitsprozesse systematisch gestalten und optimieren Y1 - 2010 SN - 978-3-86880-091-3 SN - 978-3-86416-195-7 SP - 201 EP - 220 PB - mi-Wirtschaftsbuch Finanzbuch-Verl. CY - München ER - TY - CHAP A1 - Reggelin, Tobias A1 - Galka, Stefan A1 - Strassburger, Steffen A1 - Lang, Sebastian T1 - Introduction to the Minitrack “Simulation Modeling and Digital Twins for Decision Making in the Age of Industry 4.0” T2 - Proceedings of the 56th Hawaii International Conference on System Sciences (HICSS), January 3-6, 2023, Lahaina, Hawaii N2 - The minitrack contains contributions with a focus on simulation modeling and digital twins and decision making in the context of Industry 4.0. The use of simulation models and digital twins is manifold, from planning to virtual commission and real-time operational decision support. Cyber-physical systems integrate the real world and the virtual world to enable decision making in the age of Industry 4.0. For example, customer decisions and supply disruptions which directly influence manufacturing and logistics systems require immediate decisions. Thus, models must have the capability to support decision making in manufacturing as well as in internal and external logistics in real-time. Methods include discrete-event simulation, discrete-rate simulation, hybrid simulation, system dynamics simulation, the combination of simulation modeling with machine learning or optimization heuristics, prescriptive analytics, and adaptive systems. Furthermore, this minitrack addresses simulation education and simulation models used for education and training in manufacturing and logistics. Y1 - 2023 UR - https://aisel.aisnet.org/cgi/viewcontent.cgi?article=1456&context=hicss-56 U6 - https://doi.org/10.24251/HICSS.2023.179 SP - 1436 EP - 1437 PB - ScholarSpace ER - TY - CHAP A1 - Galka, Stefan A1 - Meißner, Sebastian A1 - Obermeir, Theresia ED - Fottner, Johannes T1 - Digitale Zwillinge für die Steuerung innerbetrieblicher Transportsysteme T2 - 32. Deutscher Materialfluss-Kongress 2025, Garching bei München, 20.-21.3.2025 N2 - Im Rahmen des Forschungsprojektes "Digitale(r) Zwillinge zur dynamischen Simulation für die Planung und Steuerung innerbetrieblicher Transportsysteme im Rahmen der digitalen Fabrik" (TwInTraSys) wurde ein simulationsbasierter Digitaler Zwilling zur vorausschauenden Entscheidungsunterstützung im operativen Betrieb von innerbetrieblichen Transportsystemen entwickelt. Das Konzept wurde demonstratorisch umgesetzt und bei verschiedenen Anwendungsunternehmen getestet und validiert. Im Folgenden werden die Einsatzmöglichkeiten im Zentrallager der Firma HiPP am Beispiel einer Ressourceneinsatzplanung dargestellt. KW - Innerbetrieblicher Transport KW - Simulation KW - Digitale Zwillinge Y1 - 2025 PB - VDI-Verlag ER - 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 - TY - RPRT A1 - Schuhegger, Lukas A1 - Galka, Stefan T1 - Herausforderungen von produzierenden Startups N2 - Startups bringen mit ihrer Dynamik und neuen innovativen Geschäftsmodellen frischen Wind in die deutsche Unternehmenslandschaft. Die disruptiven Ansätze gestalten die Zukunft und damit geraten sie immer weiter in den Fokus, unter anderem auch für Investoren. Das Ziel der Studie ist es, Zusammenhänge zwischen Herausforderungen und Eigenschaften von produzierenden Startups darzulegen. Dieses Wissen soll an andere Startups weitergegeben werden, um die Erfolgschancen in der Gründerszene zu erhöhen. Im Juli 2021 wurde hierzu eine Umfrage entworfen, um die Erfahrungen von Gründern und Startup-Mitarbeitern zu sammeln und die spezifischen Herausforderungen besser zu verstehen. KW - Unternehmensgründung KW - Produktion KW - Studie KW - Logistik KW - Herausforderungen KW - Herausforderung bei der Gründung KW - Technologie Start-ups KW - Hochlauf KW - Phasenmodell Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-88520 ER - TY - CHAP A1 - Galka, Stefan A1 - Strassburger, Steffen A1 - Lang, Sebastian A1 - Reggelin, Tobias ED - Bui, Tung T1 - Introduction to the Minitrack on Simulation Modeling and Digital Twins for Decision Making in the Age of Industry 4.0 T2 - Proceedings of the 57th Hawaii International Conference on System Sciences (HICSS), January3-6, 2024, Honolulu, Hawaii N2 - The minitrack contains contributions with a focus on simulation modeling and digital twins and decision making in the context of Industry 4.0. The use of simulation models and digital twins is manifold, from planning to virtual commission and real-time operational decision support. Cyber-physical systems integrate the real world and the virtual world to enable decision making in the age of Industry 4.0. For example, customer decisions and supply disruptions which directly influence manufacturing and logistics systems require immediate decisions. Thus, models must have the capability to support decision making in manufacturing as well as in internal and external logistics in real-time. Methods include discrete-event simulation, discrete-rate simulation, hybrid simulation, system dynamics simulation, the combination of simulation modeling with machine learning or optimization heuristics, prescriptive analytics, and adaptive systems. Furthermore, this minitrack addresses simulation education and simulation models used for education and training in manufacturing and logistics. Y1 - 2024 SN - 978-0-9981331-7-1 U6 - https://doi.org/10.24251/HICSS.2024.206 SP - 1647 EP - 1648 PB - ScholarSpace ER - TY - JOUR A1 - Weigert, Alexander A1 - Galka, Stefan A1 - Dünnweber, Jan A1 - Meißner, Sebastian A1 - Riege, Jacob A1 - Böck, Hendrik A1 - Wagner, Martin T1 - Simulationsframework mit Anordnungsalgorithmus von Petri-Netzen JF - Zeitschrift für wirtschaftlichen Fabrikbetrieb N2 - Die serienmäßige Produktion von Elektrolysezellen befindet sich im Anfangsstadium, sodass belastbare Erfahrungen für standardisierte Produktionssysteme fehlen. Die Planung ist daher durch hohe Unsicherheit geprägt. Unterschiedliche Gestaltungsmöglichkeiten der Produktionssysteme müssen frühzeitig bewertet und ihre Leistungsfähigkeit mit dynamischen Methoden, wie der Simulation, abgesichert werden. Anhand eines von den Autoren entwickelten Simulationsframeworks mit automatisierter Modellgenerierung auf Basis der Petri-Netz-Logik zeigt dieser Beitrag die Möglichkeit der Simulation von Produktionssystemen in der Planung. Ein besonderes Leistungsmerkmal des Frameworks ist, dass zunächst unübersichtlich generierte Modelle mit einem Graphenalgorithmus so angeordnet werden, dass ihre Funktionsweise aus der Darstellung nachvollziehbar wird. KW - Continuous Simulation; Framework; Automated Simulation Model Generation; Graph-Layout-algorithm; Petri-Net Y1 - 2026 U6 - https://doi.org/10.1515/zwf-2026-1035 VL - 121 IS - 3 SP - 125 EP - 130 PB - DeGruyter ER -