@inproceedings{SchmidWildSchneidewindetal., author = {Schmid, Florian and Wild, Tobias and Schneidewind, Jan and Vogl, Tobias and Schuhegger, Lukas and Galka, Stefan}, title = {Simulation Based Approach for Reconfiguration and Ramp up Scenario Analysis in Factory Planning}, series = {Proceedings of the 2022 Winter Simulation Conference (WSG), 11-14 Dec. 2022, Singapore}, booktitle = {Proceedings of the 2022 Winter Simulation Conference (WSG), 11-14 Dec. 2022, Singapore}, publisher = {IEEE}, isbn = {978-1-6654-7661-4}, doi = {10.1109/WSC57314.2022.10015310}, pages = {2842 -- 2852}, abstract = {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.}, language = {en} } @inproceedings{GalkaSchuhegger, author = {Galka, Stefan and Schuhegger, Lukas}, title = {Integration of Discrete-event Simulation in the Planning of a Hydrogen Electrolyzer Production Facility}, series = {Proceedings of the 2022 Winter Simulation Conference (WSC), 11-14 Dec. 2022, Singapore}, booktitle = {Proceedings of the 2022 Winter Simulation Conference (WSC), 11-14 Dec. 2022, Singapore}, editor = {Feng, B. and Pedrielli, G. and Peng, Y. and Shashaani, S. and Song, E. and Corlu, C.G. and Lee, L.H. and Chew, E.P. and Roeder, T. and Lendermann, P.}, publisher = {IEEE}, address = {Singapore}, pages = {2}, abstract = {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.}, language = {en} } @inproceedings{UlbrichGalkaGuenthner, author = {Ulbrich, Alexander and Galka, Stefan and G{\"u}nthner, Willibald A.}, title = {Secure planning of order picking systems with the aid of simulation}, series = {Proceedings of th 43rd Hawaii International Conference on System Sciences (HICSS), 5-8 Jan. 2010, Koloa, Kauai, Hawaii}, booktitle = {Proceedings of th 43rd Hawaii International Conference on System Sciences (HICSS), 5-8 Jan. 2010, Koloa, Kauai, Hawaii}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-0-7695-3869-3}, issn = {1530-1605}, doi = {10.1109/HICSS.2010.326}, pages = {1 -- 7}, abstract = {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.}, language = {de} } @inproceedings{SchneidewindGalka, author = {Schneidewind, Jan and Galka, Stefan}, title = {Interactive reinforcement learning-based factory layout planning}, series = {13th Conference on Learning Factories (CLF 2023), 9-11 May 2023, Reutlingen, Germany}, booktitle = {13th Conference on Learning Factories (CLF 2023), 9-11 May 2023, Reutlingen, Germany}, publisher = {SSRN}, pages = {6}, abstract = {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.}, language = {en} } @misc{Galka, author = {Galka, Stefan}, title = {Podcast "Irgendwas mit Logistik", Folge 82: Automatisierungstechnik richtig und fair abnehmen}, edition = {ver{\"o}ffentlicht am 05.04.2021}, abstract = {Professoren wird h{\"a}ufig 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 {\"u}ber ein ziemlich praktisches Thema zu sprechen - Inbetriebnahmen von Automatisierungstechnik. Stefan, Jens und Thomas z{\"a}umen das Pferd von hinten auf und versuchen zu kl{\"a}ren, wer welche Verantwortungen und (ggf. verdeckten) Interessen bei der Realisierung von technischen Gewerken hat, welche Richtlinien bei der Durchf{\"u}hrung helfen k{\"o}nnen und definieren gemeinsam, wie die Inbetriebnahme zum Erfolg wird.}, language = {de} } @inproceedings{GalkaScherbarth, author = {Galka, Stefan and Scherbarth, Christoph}, title = {Simulationsbasierte Untersuchung der Grenzproduktivit{\"a}t von Robotern in einem AutoStore-Lagersystem}, series = {Simulation in Produktion und Logistik 2021 : Erlangen, 15.-17. September 2021}, booktitle = {Simulation in Produktion und Logistik 2021 : Erlangen, 15.-17. September 2021}, editor = {Franke, J{\"o}rg and Schuderer, Peter}, publisher = {Cuvillier Verlag}, address = {G{\"o}ttingen}, isbn = {978-3-7369-7479-1}, pages = {197 -- 206}, language = {de} } @book{Galka, author = {Galka, Stefan}, title = {AutoStore - was Nutzer {\"u}ber das System berichten k{\"o}nnen}, address = {Regensburg}, isbn = {978-3-9818209-9-7}, doi = {10.35096/othr/pub-646}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-6463}, publisher = {Ostbayerische Technische Hochschule Regensburg}, subject = {Kleinteil}, language = {de} } @inproceedings{StrassburgerGalkaLangetal., author = {Strassburger, Steffen and Galka, Stefan and Lang, Sebastian and Reggelin, Tobias}, title = {Introduction to the Minitrack on Simulation Modeling, Artificial Intelligence and Digital Twins for Decision Making in Production and Logistics}, series = {Proceedings of the 58th Hawaii International Conference on System Sciences, January 7-10, 2025, Honolulu, Hawaii}, booktitle = {Proceedings of the 58th Hawaii International Conference on System Sciences, January 7-10, 2025, Honolulu, Hawaii}, editor = {Bui, Tung}, publisher = {University of Hawaii at Manoa}, isbn = {978-0-9981331-8-8}, doi = {10.24251/HICSS.2025.205}, pages = {1677 -- 1678}, abstract = {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.}, language = {en} } @misc{WildGalkaWappleretal., author = {Wild, Tobias and Galka, Stefan and Wappler, Mona and Xing, Lu}, title = {Integrating supply chain aspects into factory planning, a simulation approach}, series = {The journey to sustainable supply chains: proceedings of the 26th International Symposium on Logistics (ISL 2022), 10-13th July 2022, Cork, Ireland}, journal = {The journey to sustainable supply chains: proceedings of the 26th International Symposium on Logistics (ISL 2022), 10-13th July 2022, Cork, Ireland}, editor = {Potter, A. and Pawar, K. S. and O'Reilly, S. and Jimo, A.}, publisher = {Nottingham University Business School, UK}, address = {Nottingham, UK}, isbn = {978-0-85358-350-9}, pages = {6}, abstract = {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.}, language = {de} } @inproceedings{Galka, author = {Galka, Stefan}, title = {Untersuchung von Auftragsfreigabestrategien f{\"u}r mehrzonige Kommissioniersysteme im Online-Lebensmittelhandel}, series = {ASIM SST 2022 Proceedings Langbeitr{\"a}ge, 26. ASIM Symposium Simulationstechnik: 25.07.-27.07.2022, TU Wien}, volume = {2022}, booktitle = {ASIM SST 2022 Proceedings Langbeitr{\"a}ge, 26. ASIM Symposium Simulationstechnik: 25.07.-27.07.2022, TU Wien}, publisher = {ARGESIM Verlag}, address = {Wien}, organization = {Gesellschaft f{\"u}r Informatik. Arbeitskreis f{\"u}r Simulation in der Fertigungstechnik}, isbn = {978-3-901608-97-1}, doi = {10.11128/arep.20.a2021}, pages = {23 -- 30}, abstract = {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.}, subject = {Simulation}, language = {de} } @inproceedings{GalkaGuenthnerUlbrich, author = {Galka, Stefan and G{\"u}nthner, Willibald A. and Ulbrich, Alexander}, title = {Planning of order-picking-systems with support of discrete simulation}, series = {Logistics and Supply Chain Management: Deutsch-Russische Perspektiven. Proceedings of the 5th German-Russian Logistics Workshop (DR-LOG10)}, booktitle = {Logistics and Supply Chain Management: Deutsch-Russische Perspektiven. Proceedings of the 5th German-Russian Logistics Workshop (DR-LOG10)}, language = {en} } @article{GalkaKlenkGuenthner, author = {Galka, Stefan and Klenk, Eva Marianne and G{\"u}nthner, Willibald A.}, title = {Einfluss von Artikeleigenschaften auf die Entnahmezeit in Kommissioniersystemen}, series = {Logistics Journal / Proceedings}, journal = {Logistics Journal / Proceedings}, publisher = {WGTL, Wissenschaftliche Gesellschaft f{\"u}r Technische Logistik e. V.}, address = {Stuttgart ; Dortmund}, issn = {2192-9084}, doi = {10.2195/lj_Proc_galka_de_201610_01}, url = {http://nbn-resolving.de/urn:nbn:de:0009-14-44540}, abstract = {Das Kommissionieren z{\"a}hlt zu den arbeitsintensivsten Aufgaben in der Logistik. Aus diesem Grund ist es wichtig, m{\"o}glichst genau die erwarteten Prozesszeiten f{\"u}r diese Aufgabe zu bestimmen. Ein verbreiteter Ansatz f{\"u}r die Bestimmung von Prozesszeiten f{\"u}r manuelle T{\"a}tigkeiten beim Kommissionieren ist die Methods-Time-Measurement (MTM). Um eine Vorgabezeit mittels MTM zu bestimmen, m{\"u}ssen Einflussfaktoren spezifiziert werden. Dieser Beitrag zeigt anhand der Greifzeit auf, wie diese Einfluss-faktoren auf Grundlage von Artikelstammdaten bestimmt werden k{\"o}nnen. Weiterhin wird der Unterschied zwischen einer f{\"u}r jeden Artikel individuell bestimmten Greifzeit und der Greifzeit basierend auf repr{\"a}sentativen Eigenschaften von Artikelgruppen verglichen. Wesentlich wird dabei die mittels MTM bestimmte Greifzeit durch das Gewicht und die Abmessungen (Sperrigkeit) beeinflusst.}, language = {de} } @article{GalkaRammelmeierGuenthner, author = {Galka, Stefan and Rammelmeier, Tobias and G{\"u}nthner, Willibald A.}, title = {Fehlervermeidung in der kommissionierung}, series = {Logistics Journal}, journal = {Logistics Journal}, publisher = {WGTL, Wissenschaftliche Gesellschaft f{\"u}r Technische Logistik e. V.}, address = {Stuttgart ; Dortmund}, issn = {2192-9084}, doi = {10.2195/lj_Proc_rammelmeier_de_201210_01}, url = {http://nbn-resolving.de/urn:nbn:de:0009-14-34494}, pages = {1 -- 8}, abstract = {Manuelle Kommissioniersysteme sind aufgrund ihrer Flexibilit{\"a}t weit verbreitet, jedoch treten bei diesen auch vermehrt Kommissionierfehler auf, die weitreichende Folgen haben k{\"o}nnen. Deshalb werden zu Beginn des Beitrags die Auswirkungen und Ursachen von Kommissionierfehlern betrachtet. Der Fokus des Beitrags liegt auf der Darlegung von M{\"o}glichkeiten zur Fehlervermeidung. Dabei wird ein ganzheitlicher Ansatz verfolgt, der Maßnahmen aus den Handlungsfeldern Technik, Prozess, Organisation und Motivation umfasst. Als Ausblick auf zuk{\"u}nftige technische Hilfsmittel zur Fehlervermeidung wird das Augmented-Reality-unterst{\"u}tzte System Pick-by-Vision aus der Forschung vorgestellt, das wesentliche Vorteile existierender Techniken der Informationsbereitstellung vereinigt.}, language = {en} } @inproceedings{ReggelinGalkaIvanovetal., author = {Reggelin, Tobias and Galka, Stefan and Ivanov, Dmitry and Lang, Sebastian}, title = {Introduction to the Minitrack on Modeling and Decision Making in Manufacturing and Logistics in the Age of Industry 4.0}, series = {Proceedings of the 54th Hawaii International Conference on System Sciences (HICSS): 2021 Hawaii, USA}, booktitle = {Proceedings of the 54th Hawaii International Conference on System Sciences (HICSS): 2021 Hawaii, USA}, publisher = {University of Hawai'i at Manoa Hamilton Library}, address = {Honolulu, HI}, isbn = {978-0-9981331-4-0}, doi = {10.24251/HICSS.2021.198}, pages = {1643 -- 1644}, abstract = {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.}, language = {de} } @inproceedings{HaimerlTschernitzSchilleretal., author = {Haimerl, Simon and Tschernitz, Christoph and Schiller, Tobias and Weig, Christoph and Briem, Ulrich and Galka, Stefan}, title = {Development of a Simulation Framework for Urban Ropeway Systems and Analysis of the Planned Ropeway Network in Regensburg, Germany}, series = {Proceedings of the 2022 Winter Simulation Conference (WSC), 11-14 Dec. 2022, Singapore}, booktitle = {Proceedings of the 2022 Winter Simulation Conference (WSC), 11-14 Dec. 2022, Singapore}, publisher = {IEEE}, isbn = {978-1-6654-7661-4}, doi = {10.1109/WSC57314.2022.10015510}, pages = {1413 -- 1424}, abstract = {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.}, language = {en} } @article{KlenkGalka, author = {Klenk, Eva Marianne and Galka, Stefan}, title = {Analysis of real-time tour building and scheduling strategies for in-plant milk-run systems with volatile transportation demand}, series = {IFAC - PapersOnLine}, volume = {52}, journal = {IFAC - PapersOnLine}, number = {13}, publisher = {Elsevier}, doi = {10.1016/j.ifacol.2019.11.517}, pages = {2110 -- 2115}, abstract = {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.}, language = {en} } @article{GalkaWappler, author = {Galka, Stefan and Wappler, Mona}, title = {Integration of cash flow management and further aspects of the supply chain management in production system design}, series = {IFAC-PapersOnLine}, volume = {56}, journal = {IFAC-PapersOnLine}, number = {2}, publisher = {IFAC / Elsevier}, doi = {10.1016/j.ifacol.2023.10.1687}, pages = {947 -- 952}, abstract = {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.}, language = {en} } @book{GalkaFottnerKlenketal., author = {Galka, Stefan and Fottner, Johannes and Klenk, Eva Marianne and Habenicht, Sebastian and Meinhardt, Ingolf and Schmidt, Thorsten}, title = {Planung von innerbetrieblichen Transportsystemen}, volume = {2022}, edition = {1. Auflage}, publisher = {Springer Vieweg}, address = {Berlin, Heidelberg}, isbn = {978-3-662-63972-6}, doi = {10.1007/978-3-662-63973-3}, pages = {231}, abstract = {Dieses Buch beschreibt bew{\"a}hrte, praxistaugliche Methoden zur Planung innerbetrieblicher Transportsysteme. Der Fokus liegt auf den wesentlichen Systemen und F{\"o}rderfahrzeugen, die derzeit in der Industrie eingesetzt werden: Gabelstapler, fahrerlose Transportfahrzeuge, Routenz{\"u}ge und Elektroh{\"a}ngebahnen. Neben einer Beschreibung relevanter Systemelemente und Gestaltungsm{\"o}glichkeiten 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 ben{\"o}tigter 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 einschl{\"a}giger Studienf{\"a}cher bekommen einen vertieften Einblick in die Umsetzung der Methoden.}, subject = {Intralogistik}, language = {de} } @inproceedings{GalkaSchmid, author = {Galka, Stefan and Schmid, Florian}, title = {Initialization of Simulation-Based Digital Twins for Internal Transport Systems}, series = {IFAC-PapersOnLine}, volume = {58}, booktitle = {IFAC-PapersOnLine}, number = {19}, editor = {Schlund, Sebastian and Ansari, Fazel}, address = {Wien}, organization = {International Federation of Automatic Control (IFAC)}, issn = {2405-8963}, doi = {10.1016/j.ifacol.2024.09.127}, pages = {1084 -- 1089}, abstract = {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.}, language = {en} } @inproceedings{Galka, author = {Galka, Stefan}, title = {Reducing Transient Behavior in Simulation-Based Digital Twins: A Novel Initialization Approach for Order Picking Systems}, series = {2024 Winter Simulation Conference (WSC), 15-18 December 2024, Orlando, FL, USA}, booktitle = {2024 Winter Simulation Conference (WSC), 15-18 December 2024, Orlando, FL, USA}, publisher = {IEEE}, isbn = {979-8-3315-3420-2}, doi = {10.1109/WSC63780.2024.10838961}, pages = {1434 -- 1445}, abstract = {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.}, language = {en} } @inproceedings{SchuheggerArmbrusterGalka, author = {Schuhegger, Lukas and Armbruster, Thomas and Galka, Stefan}, title = {Factory Data Model for Planning Variant Sequences, Expansion Stages and Reconfigurations}, series = {IFAC-PapersOnLine}, volume = {56}, booktitle = {IFAC-PapersOnLine}, number = {2}, publisher = {IFAC / Elsevier}, doi = {10.1016/j.ifacol.2023.10.1573}, pages = {227 -- 232}, abstract = {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.}, language = {en} } @inproceedings{RolfReggelinLangetal., author = {Rolf, Benjamin and Reggelin, Tobias and Lang, Sebastian and Galka, Stefan}, title = {Developing a Decision Support System for Integrated Decision-Making in Purchasing and Scheduling under Lead Time Uncertainty}, series = {Proceedings of the 55th Hawaii International Conference on System Sciences (HICSS55): January 3-7, 2022, Maui, Hawaii, USA}, volume = {2022}, booktitle = {Proceedings of the 55th Hawaii International Conference on System Sciences (HICSS55): January 3-7, 2022, Maui, Hawaii, USA}, doi = {10.24251/HICSS.2022.247}, pages = {1964 -- 1973}, abstract = {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.}, language = {en} } @inproceedings{KaukeFottnerGalka, author = {Kauke, Dirk and Fottner, Johannes and Galka, Stefan}, title = {Digital Twins in Order Picking Systems for Operational Decision Support}, series = {Proceedings of the 54th Hawaii International Conference on System Sciences (HICSS): 2021 Hawaii, USA}, booktitle = {Proceedings of the 54th Hawaii International Conference on System Sciences (HICSS): 2021 Hawaii, USA}, publisher = {University of Hawai'i at Manoa Hamilton Library}, address = {Honolulu, HI}, isbn = {978-0-9981331-4-0}, doi = {10.24251/HICSS.2021.200}, pages = {1655 -- 1664}, abstract = {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.}, language = {en} } @incollection{FottnerGalkaHabenichtetal., author = {Fottner, Johannes and Galka, Stefan and Habenicht, Sebastian and Klenk, Eva Marianne and Meinhardt, Ingolf and Schmidt, Thorsten}, title = {Gestaltungsprinzipien f{\"u}r innerbetriebliche Fahrzeugsysteme}, series = {Planung von innerbetrieblichen Transportsystemen}, booktitle = {Planung von innerbetrieblichen Transportsystemen}, editor = {Fottner, Johannes and Galka, Stefan and Habenicht, Sebastian and Klenk, Eva Marianne and Meinhardt, Ingolf and Schmidt, Thorsten}, edition = {First Online: 07 May 2022}, publisher = {Springer}, address = {Berlin, Heidelberg}, isbn = {978-3-662-63972-6}, doi = {10.1007/978-3-662-63973-3_3}, pages = {67 -- 76}, abstract = {Bei der Planung von innerbetrieblichen Transportsystemen besteht die Aufgabe darin, Transportsysteme so zu gestalten und zu dimensionieren, dass Unternehmensziele unter Ber{\"u}cksichtigung gegebener Rahmenbedingungen m{\"o}glichst ideal erf{\"u}llt werden. Ob ein geplantes System schlussendlich den an die L{\"o}sung 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, m{\"u}ssen die Systembausteine in geeigneter Kombination ausgestaltet und dimensioniert werden. Ans{\"a}tze daf{\"u}r werden in Kap. 5 ausf{\"u}hrlich vorgestellt.}, language = {de} } @book{LiebKlenkGalkaetal., author = {Lieb, Christian and Klenk, Eva Marianne and Galka, Stefan and Keuntje, Christopher}, title = {Einsatz von Routenzugsystemen zur Produktionsversorgung : Studie zu Planung Steuerung und Betrieb}, publisher = {fml - Lehrstuhl f{\"u}r F{\"o}rdertechnik Materialfluß Logistik Technische Universit{\"a}t M{\"u}nchen}, address = {Garching b. M{\"u}nchen}, isbn = {978-3-941702-79-0}, language = {de} } @article{Galka, author = {Galka, Stefan}, title = {Tipps zur Absicherung der Investitionsentscheidung in ein Autostore-System}, series = {F{\"o}rdern + Heben}, journal = {F{\"o}rdern + Heben}, number = {1-2}, publisher = {Vereinigte Fachverlage GmbH}, address = {Mainz}, pages = {12 -- 14}, language = {de} } @article{GalkaFollathBross, author = {Galka, Stefan and Follath, Alexander and Bross, Florian}, title = {Vorgehensmodell zur Erstellung Digitaler Zwillinge f{\"u}r Produktion und Logistik}, series = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, volume = {117}, journal = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, number = {11}, editor = {Bauer, Wilhelm and Volk, Wolfram and Z{\"a}h, Michael}, publisher = {De Gruyter}, address = {Berlin}, doi = {10.1515/zwf-2022-1127}, pages = {691 -- 696}, abstract = {Der Digitale Zwilling (DZ) ist ein wichtiger Bestandteil der Industrie 4.0 und erm{\"o}glicht 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 f{\"u}r die Erstellung eines Digitalen Zwillings im Bereich der Produktion und Logistik aufgezeigt werden. Das Vorgehensmodell hilft bei der Einordnung, f{\"u}r welche Anwendungsf{\"a}lle ein Digitaler Zwilling entwickelt werden kann, welche Schritte bei einer Umsetzung erfolgen m{\"u}ssen, und gibt einen {\"U}berblick {\"u}ber die Voraussetzungen und Komplexit{\"a}t 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.}, language = {de} } @article{Galka, author = {Galka, Stefan}, title = {Operating strategies for in-plant milk-run systems}, series = {IFAC-Papers OnLine}, volume = {48}, journal = {IFAC-Papers OnLine}, number = {3}, publisher = {Elsevier}, address = {Frankfurt}, doi = {10.1016/j.ifacol.2015.06.361}, pages = {1882 -- 1887}, abstract = {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.}, language = {en} } @inproceedings{GalkaKlenkGuenthner, author = {Galka, Stefan and Klenk, Eva Marianne and G{\"u}nthner, Willibald A.}, title = {Planning of production supermarkets for production supply}, series = {Proceedings of 2013 IEEE International Conference on Service Operations and Logistics, and Informatics, 28-30 July 2013, Dongguan, China}, booktitle = {Proceedings of 2013 IEEE International Conference on Service Operations and Logistics, and Informatics, 28-30 July 2013, Dongguan, China}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4799-0530-0}, doi = {10.1109/SOLI.2013.6611458}, pages = {456 -- 461}, abstract = {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.}, language = {de} } @article{GalkaKlenkGuenthner, author = {Galka, Stefan and Klenk, Eva Marianne and G{\"u}nthner, Willibald A.}, title = {Potenziale einer flexiblen Routenzugsteuerung: Strategien zum besseren Umgang mit schwankenden Transportbedarfen}, series = {Zeitschrift fuer Wirtschaftlichen Fabrikbetrieb : ZWF}, volume = {110}, journal = {Zeitschrift fuer Wirtschaftlichen Fabrikbetrieb : ZWF}, number = {12}, publisher = {de Gruyter}, address = {Berlin}, issn = {2511-0896}, doi = {10.3139/104.111444}, pages = {805 -- 809}, language = {de} } @incollection{Galka, author = {Galka, Stefan}, title = {Planung und Auswahl von Kommissioniersystemen}, series = {MTM in einer globalisierten Wirtschaft : Arbeitsprozesse systematisch gestalten und optimieren}, booktitle = {MTM in einer globalisierten Wirtschaft : Arbeitsprozesse systematisch gestalten und optimieren}, editor = {Britzke, Bernd}, publisher = {mi-Wirtschaftsbuch Finanzbuch-Verl.}, address = {M{\"u}nchen}, isbn = {978-3-86880-091-3}, pages = {201 -- 220}, language = {de} } @inproceedings{ReggelinGalkaStrassburgeretal., author = {Reggelin, Tobias and Galka, Stefan and Strassburger, Steffen and Lang, Sebastian}, title = {Introduction to the Minitrack "Simulation Modeling and Digital Twins for Decision Making in the Age of Industry 4.0"}, series = {Proceedings of the 56th Hawaii International Conference on System Sciences (HICSS), January 3-6, 2023, Lahaina, Hawaii}, booktitle = {Proceedings of the 56th Hawaii International Conference on System Sciences (HICSS), January 3-6, 2023, Lahaina, Hawaii}, publisher = {ScholarSpace}, doi = {10.24251/HICSS.2023.179}, pages = {1436 -- 1437}, abstract = {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.}, language = {en} } @inproceedings{GalkaMeissnerObermeir, author = {Galka, Stefan and Meißner, Sebastian and Obermeir, Theresia}, title = {Digitale Zwillinge f{\"u}r die Steuerung innerbetrieblicher Transportsysteme}, series = {32. Deutscher Materialfluss-Kongress 2025, Garching bei M{\"u}nchen, 20.-21.3.2025}, booktitle = {32. Deutscher Materialfluss-Kongress 2025, Garching bei M{\"u}nchen, 20.-21.3.2025}, editor = {Fottner, Johannes}, publisher = {VDI-Verlag}, pages = {6}, abstract = {Im Rahmen des Forschungsprojektes "Digitale(r) Zwillinge zur dynamischen Simulation f{\"u}r die Planung und Steuerung innerbetrieblicher Transportsysteme im Rahmen der digitalen Fabrik" (TwInTraSys) wurde ein simulationsbasierter Digitaler Zwilling zur vorausschauenden Entscheidungsunterst{\"u}tzung im operativen Betrieb von innerbetrieblichen Transportsystemen entwickelt. Das Konzept wurde demonstratorisch umgesetzt und bei verschiedenen Anwendungsunternehmen getestet und validiert. Im Folgenden werden die Einsatzm{\"o}glichkeiten im Zentrallager der Firma HiPP am Beispiel einer Ressourceneinsatzplanung dargestellt.}, language = {de} } @article{StaabKlenkGalkaetal., author = {Staab, T. and Klenk, Eva Marianne and Galka, Stefan and G{\"u}nthner, Willibald A.}, title = {Efficiency in in-plant milk-run systems - The influence of routing strategies on system utilization and process stability}, series = {Journal of Simulation}, volume = {10}, journal = {Journal of Simulation}, number = {2}, publisher = {Taylor \& Francis}, address = {Abingdon}, issn = {1747-7786}, doi = {10.1057/jos.2015.6}, pages = {137 -- 143}, abstract = {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.}, language = {en} } @article{SchuheggerKaraGalkaetal., author = {Schuhegger, Lukas and Kara, Sinan and Galka, Stefan and D{\"u}nnweber, Jan and Meißner, Sebastian}, title = {Umzugsplanung mit Fabrikdatenmodellen und Virtual Reality}, series = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, volume = {119}, journal = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, number = {11}, publisher = {de Gruyter}, issn = {2511-0896}, doi = {10.1515/zwf-2024-1154}, pages = {799 -- 804}, abstract = {Angesichts eines dynamischen industriellen Umfelds m{\"u}ssen produzierende Unternehmen flexibel bleiben und sich kontinuierlich anpassen, um ihre Wettbewerbsf{\"a}higkeit zu erhalten. Eine effektive Planung von Restrukturierungen in Produktionssystemen, oft als Umzugsplanung bezeichnet, ist entscheidend, um Verz{\"o}gerungen zu vermeiden und Stillstandszeiten zu minimieren. Die Identifikation von Umzugsf{\"a}llen, welche den Umfang umzuziehender Ressourcen wie Maschinen, Anlagen, Ausr{\"u}stungen und Arbeitspl{\"a}tzen beschreiben und die Definition zugeh{\"o}riger Aufgaben sind essenzielle Schritte der Umzugsplanung. Dieser Beitrag stellt eine Vorgehensweise zur Bestimmung von Umzugsf{\"a}llen mittels eines Fabrikdatenmodells vor, erg{\"a}nzt durch eine Visualisierung in Virtual Reality, um Planende bei der Umzugsplanung zu unterst{\"u}tzen.}, language = {de} } @inproceedings{MarinkovicGalkaMeissner, author = {Marinkovic, Minja and Galka, Stefan and Meißner, Sebastian}, title = {Digital Twins for Internal Transport Systems: Use Cases, Functions, and System Architecture}, series = {Proceedings of the 56th Hawaii International Conference on System Sciences: January 3-6, 2023, Maui, Hawaii, USA}, booktitle = {Proceedings of the 56th Hawaii International Conference on System Sciences: January 3-6, 2023, Maui, Hawaii, USA}, publisher = {University of Hawaiʻi at Mānoa}, address = {Honolulu, HI}, isbn = {978-0-9981331-6-4}, pages = {1195 -- 1204}, abstract = {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.}, language = {en} } @inproceedings{SchmidGalkaMarinkovicetal., author = {Schmid, Florian and Galka, Stefan and Marinkovic, Minja and Meißner, Sebastian}, title = {Simulationsbasierte Untersuchung von Abstraktionsgraden im Kontext Digitaler Zwillinge f{\"u}r innerbetriebliche Transportsysteme}, series = {Tagungsband 20. ASIM-Fachtagung Simulation in Produktion und Logistik, Ilmenau, 13. - 15. September 2023}, booktitle = {Tagungsband 20. ASIM-Fachtagung Simulation in Produktion und Logistik, Ilmenau, 13. - 15. September 2023}, editor = {Bergmann, S{\"o}ren and Feldkamp, Niclas and Souren, Rainer and Straßburger, Steffen}, publisher = {Universit{\"a}tsverlag Ilmenau}, address = {Ilmenau}, isbn = {978-3-86360-276-5}, doi = {10.22032/DBT.57794}, pages = {135 -- 144}, abstract = {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.}, language = {de} } @inproceedings{GalkaSchmidGrasseretal., author = {Galka, Stefan and Schmid, Florian and Grasser, Dominik and Hohm, Jonathan and Stauber, Stephan and Meißner, Sebastian}, title = {Integration eines SAP-Transportleitsystem in eine Simulationsumgebung zur Unterst{\"u}tzung von Entscheidungen im operativen Betrieb}, series = {Tagungsband 20. ASIM-Fachtagung Simulation in Produktion und Logistik, Ilmenau, 13. - 15. September 2023}, booktitle = {Tagungsband 20. ASIM-Fachtagung Simulation in Produktion und Logistik, Ilmenau, 13. - 15. September 2023}, publisher = {Universit{\"a}tsverlag Ilmenau}, address = {ILmenau}, isbn = {978-3-86360-276-5}, doi = {10.22032/DBT.57813}, pages = {281 -- 291}, abstract = {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.}, language = {de} } @inproceedings{GalkaWeigert, author = {Galka, Stefan and Weigert, Alexander}, title = {Systematik zur planungsbegleitenden Simulation bei der Konzeptplanung von Produktionssystemen - ein Anwendungsfall aus der Elektrolysestack-Produktion}, series = {Simulation in Produktion und Logistik 2025}, booktitle = {Simulation in Produktion und Logistik 2025}, editor = {Schmidt, Thorsten and K{\"u}hn, Mathias and Rank, Sebastian}, publisher = {Technische Universit{\"a}t Dresden, Professur f{\"u}r Technische Logistik}, address = {Dresden}, isbn = {978-3-86780-806-4}, doi = {10.25368/2025.278}, pages = {45-1 -- 45-10}, abstract = {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.}, language = {de} } @inproceedings{GalkaMeissner, author = {Galka, Stefan and Meißner, Sebastian}, title = {Einsatz von Digitalen Zwillingen f{\"u}r die operative Steuerung von innerbetrieblichen Transportsystemen}, series = {Simulation in Produktion und Logistik 2025}, booktitle = {Simulation in Produktion und Logistik 2025}, editor = {Schmidt, Thorsten and Rank, Sebastian and K{\"u}hn, Mathias}, publisher = {Technische Universit{\"a}t Dresden, Professur f{\"u}r Technische Logistik}, address = {Dresden}, isbn = {978-3-86780-806-4}, doi = {10.25368/2025.280}, pages = {47-1 -- 47-11}, abstract = {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.}, language = {de} } @inproceedings{GalkaWeigert, author = {Galka, Stefan and Weigert, Alexander}, title = {Petri Net Structures for Automated Model Generation through Process Descriptions}, series = {IFAC Papers OnLine}, volume = {59}, booktitle = {IFAC Papers OnLine}, number = {10}, publisher = {Elsevier}, doi = {10.1016/j.ifacol.2025.09.093}, pages = {542 -- 547}, abstract = {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.}, language = {en} } @inproceedings{Galka, author = {Galka, Stefan}, title = {Integration and usage of simulation-based digital twins in internal logistics systems}, series = {IFAC Papers OnLine}, volume = {59}, booktitle = {IFAC Papers OnLine}, number = {10}, publisher = {Elsevier}, doi = {10.1016/j.ifacol.2025.09.152}, pages = {897 -- 902}, abstract = {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.}, language = {en} } @article{GinsterWeigertHeymetal., author = {Ginster, Vinzenz and Weigert, Alexander and Heym, Maximilian Klaus and Beier, Christoph J{\"u}rgen Anton and Schiebahn, Alexander and Galka, Stefan}, title = {Factory simulation of adhesive bonding processes considering pot-life-induced waste}, series = {Journal of Advanced Joining Processes}, volume = {13}, journal = {Journal of Advanced Joining Processes}, publisher = {Elsevier}, issn = {2666-3309}, doi = {10.1016/j.jajp.2026.100375}, pages = {7}, abstract = {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.}, language = {en} } @inproceedings{GalkaMeissner, author = {Galka, Stefan and Meißner, Sebastian}, title = {Simulation-Based Digital Twins for Internal Transport Systems}, series = {Procedia Computer Science}, volume = {274}, booktitle = {Procedia Computer Science}, publisher = {Elsevier}, doi = {10.1016/j.procs.2025.12.016}, pages = {161 -- 170}, abstract = {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.}, language = {en} } @inproceedings{GalkaWappler, author = {Galka, Stefan and Wappler, Mona}, title = {INTEGRATION OF CASH FLOW MANAGEMENT AND FURTHER ASPECTS OF THE SUPPLY CHAIN MANAGEMENT IN PRODUCTION SYSTEM DESIGN}, series = {IFAC-PapersOnLine}, volume = {56}, booktitle = {IFAC-PapersOnLine}, number = {2}, publisher = {International Federation of Automatic Control. Published by Elsevier Ltd.}, address = {Yokohama}, issn = {2405-8963}, doi = {10.1016/j.ifacol.2023.10.1687}, pages = {947 -- 952}, abstract = {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.}, subject = {Supply chain management}, language = {de} } @techreport{SchuheggerGalka, author = {Schuhegger, Lukas and Galka, Stefan}, title = {Herausforderungen von produzierenden Startups}, doi = {10.35096/othr/pub-8852}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-88520}, pages = {30}, abstract = {Startups bringen mit ihrer Dynamik und neuen innovativen Gesch{\"a}ftsmodellen frischen Wind in die deutsche Unternehmenslandschaft. Die disruptiven Ans{\"a}tze gestalten die Zukunft und damit geraten sie immer weiter in den Fokus, unter anderem auch f{\"u}r Investoren. Das Ziel der Studie ist es, Zusammenh{\"a}nge zwischen Herausforderungen und Eigenschaften von produzierenden Startups darzulegen. Dieses Wissen soll an andere Startups weitergegeben werden, um die Erfolgschancen in der Gr{\"u}nderszene zu erh{\"o}hen. Im Juli 2021 wurde hierzu eine Umfrage entworfen, um die Erfahrungen von Gr{\"u}ndern und Startup-Mitarbeitern zu sammeln und die spezifischen Herausforderungen besser zu verstehen.}, subject = {Unternehmensgr{\"u}ndung}, language = {de} } @inproceedings{GalkaStrassburgerLangetal., author = {Galka, Stefan and Strassburger, Steffen and Lang, Sebastian and Reggelin, Tobias}, title = {Introduction to the Minitrack on Simulation Modeling and Digital Twins for Decision Making in the Age of Industry 4.0}, series = {Proceedings of the 57th Hawaii International Conference on System Sciences (HICSS), January3-6, 2024, Honolulu, Hawaii}, booktitle = {Proceedings of the 57th Hawaii International Conference on System Sciences (HICSS), January3-6, 2024, Honolulu, Hawaii}, editor = {Bui, Tung}, publisher = {ScholarSpace}, isbn = {978-0-9981331-7-1}, doi = {10.24251/HICSS.2024.206}, pages = {1647 -- 1648}, abstract = {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.}, language = {en} } @article{WeigertGalkaDuennweberetal., author = {Weigert, Alexander and Galka, Stefan and D{\"u}nnweber, Jan and Meißner, Sebastian and Riege, Jacob and B{\"o}ck, Hendrik and Wagner, Martin}, title = {Simulationsframework mit Anordnungsalgorithmus von Petri-Netzen}, series = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, volume = {121}, journal = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, number = {3}, publisher = {DeGruyter}, doi = {10.1515/zwf-2026-1035}, pages = {125 -- 130}, abstract = {Die serienm{\"a}ßige Produktion von Elektrolysezellen befindet sich im Anfangsstadium, sodass belastbare Erfahrungen f{\"u}r standardisierte Produktionssysteme fehlen. Die Planung ist daher durch hohe Unsicherheit gepr{\"a}gt. Unterschiedliche Gestaltungsm{\"o}glichkeiten der Produktionssysteme m{\"u}ssen fr{\"u}hzeitig bewertet und ihre Leistungsf{\"a}higkeit 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 M{\"o}glichkeit der Simulation von Produktionssystemen in der Planung. Ein besonderes Leistungsmerkmal des Frameworks ist, dass zun{\"a}chst un{\"u}bersichtlich generierte Modelle mit einem Graphenalgorithmus so angeordnet werden, dass ihre Funktionsweise aus der Darstellung nachvollziehbar wird.}, language = {de} }