Journal Articles and Book Contributions

Results: 12
Created on: Wed, 29 Jun 2022 23:04:12 +0200 in 1.3214 sec

Genath, Jonas; Bergmann, Sören; Straßburger, Steffen; Spieckermann, Sven; Stauber, Stephan;
Data farming and knowledge discovery in simulation data : development of an integrated solution
Data Farming und Wissensentdeckung in Simulationsdaten : Entwicklung einer integrierten Lösung. - In: Zeitschrift für wirtschaftlichen Fabrikbetrieb, ISSN 2511-0896, Bd. 117 (2022), 3, S. 144-150

Simulation als Methode der Digitalen Fabrik hat sich seit langem zur Unterstützung der Planung von Produktions- und Logistiksystemen etabliert. In Ergänzung zu bisher vorherrschenden Simulationsstudien wird bei der hier vorgestellten Methode der Wissensentdeckung in Simulationsdaten ein Simulationsmodell als Datengenerator verwendet. Dadurch können mittels Data-Mining- und Visual-Analytics-Methoden versteckte und potenziell nützliche Ursache-Wirkungs-Beziehungen in den generierten Daten aufgedeckt werden. Bislang fehlte es jedoch an integrierten Softwarelösungen für die Praxis.
Feldkamp, Niclas; Bergmann, Sören; Conrad, Florian; Straßburger, Steffen;
A method using generative adversarial networks for robustness optimization. - In: ACM transactions on modeling and computer simulation, ISSN 1558-1195, Bd. 32 (2022), 2, S. 12:1-12:22

The evaluation of robustness is an important goal within simulation-based analysis, especially in production and logistics systems. Robustness refers to setting controllable factors of a system in such a way that variance in the uncontrollable factors (noise) has minimal effect on a given output. In this paper, we present an approach for optimizing robustness based on deep generative models, a special method of deep learning. We propose a method consisting of two Generative Adversarial Networks (GANs) to generate optimized experiment plans for the decision factors and the noise factors in a competitive, turn-based game. In a case study, the proposed method is tested and compared to traditional methods for robustness analysis including Taguchi method and Response Surface Method.
Wörrlein, Benjamin; Straßburger, Steffen;
On the usage of deep learning for modelling energy consumption in simulation models. - In: Simulation Notes Europe, ISSN 2164-5353, Bd. 30 (2020), 4, S. 165-174

With the increasing availability of data, the desire to interpret that data and use it for behavioral predictions arises. Traditionally, simulation has used data about the real system for input data analysis or within data-driven model generation. Automatically extracting behavioral descriptions from the data and representing it in a simulation model is a challenge for these approaches. Machine learning on the other hand has proven successful in extracting knowledge from large data sets and transforming it into more useful representations. Combining simulation approaches with methods from machine learning seems, therefore, promising. Representing some aspects of a real system by a traditional simulation model and others by a model generated from machine learning, a hybrid system model (HSM) is generated. This paper discusses such HSMs and suggests a specific HSM incorporating a deep learning method for predicting the power consumption of machining jobs.
Feldkamp, Niclas; Bergmann, Sören; Straßburger, Steffen;
Knowledge discovery in simulation data. - In: ACM transactions on modeling and computer simulation, ISSN 1558-1195, Bd. 30 (2020), 4, S. 24:1-24:25

This article provides a comprehensive and in-depth overview of our work on knowledge discovery in simulations. Application-wise, we focus on manufacturing simulations. Specifically, we propose and discuss a methodology for designing, executing, and analyzing large-scale simulation experiments with a broad coverage of possible system behavior targeted at generating knowledge about the system. Based on the concept of data farming, we suggest a two-phase process which starts with a data generation phase, in which a smart experiment design is used to set up and efficiently execute a large number of simulation experiments. In the second phase, the knowledge discovery phase, data mining and visually aided analysis methods are applied on the gathered simulation input and output data. This article gives insights into this knowledge discovery phase by discussing different machine learning approaches and their suitability for different manufacturing simulation problems. With this, we provide guidelines on how to conduct knowledge discovery studies within the manufacturing simulation context. We also introduce different case studies, both academic and applied, and use them to validate our methodology.
Bergmann, Sören; Straßburger, Steffen;
Automatische Modellgenerierung - Stand, Klassifizierung und ein Anwendungsbeispiel. - In: Ablaufsimulation in der Automobilindustrie, (2020), S. 333-347

Die automatische Modellgenerierung (AMG) ist ein Ansatz, der darauf abzielt, sowohl die Aufwände einer Simulationsstudie zu senken als auch die Qualität der erzeugten Modelle zu verbessern. Unter automatischer Modellgenerierung werden im Kontext der Simulation verschiedene Ansätze subsumiert, die es erlauben, Simulationsmodelle oder zumindest Teile von Simulationsmodellen mittels Algorithmen zu erzeugen. Eine umfassende Klassifizierung der Ansätze nach verschiedenen Merkmalen ist Ausgangspunkt weiterer Betrachtungen des Beitrags, in denen u. a. verschiedene technische Ansätze zur Modellgenerierung diskutiert werden. Weiterhin werden ergänzende Techniken, die die eigentliche Modellgenerierung flankierenden, wie z. B. die automatische Modellinitialisierung, diskutiert. Als ein möglicher Lösungsansatz wird beispielhaft ein Framework zur automatischen Modellgenerierung, -initialisierung und -adaption, welches das standardisierte Core Manufacturing Simulation Data (CMSD) Format als Basis nutzt, beschrieben.
Bergmann, Sören; Feldkamp, Niclas; Straßburger, Steffen;
Emulation of control strategies through machine learning in manufacturing simulations. - In: Journal of simulation, ISSN 1747-7786, Bd. 11 (2017), 1, S. 38-50

Discrete-event simulation is a well-accepted method for planning, evaluating, and monitoring processes in production and logistics. To reduce time and effort spent on creating simulation models, automatic simulation model generation is an important area in modeling methodology research. When automatically generating a simulation model from existing data sources, the correct reproduction of dynamic behavior of the modeled system is a common challenge. One example is the representation of dispatching and scheduling strategies of production jobs. When generating a model automatically, the underlying rules for these strategies are typically unknown but yet have to be adequately emulated. In this paper, we summarize our work investigating the suitability of various data mining and supervised machine learning methods for emulating job scheduling decisions based on data obtained from production data acquisition. We report on the performance of the algorithms and give recommendations for their application, including suggestions for their integration in simulation systems.
Bergmann, Sören; Stelzer, Sören; Straßburger, Steffen;
On the use of artificial neural networks in simulation-based manufacturing control. - In: Journal of simulation, ISSN 1747-7786, Bd. 8 (2014), 1, S. 76-90

The automatic generation of simulation models has been a recurring research topic for several years. In manufacturing industries, it is currently also becoming a topic of high practical relevance. A well-known challenge in most model generation approaches is the correct reproduction of the dynamic behaviour of model elements, for example, buffering or control strategies. This problem is especially relevant in simulation-based manufacturing control. In such scenarios, simulation models need to reflect the current state and behaviour of the real system in a highly accurate way, otherwise its suggested control decisions may be inaccurate or even dangerous towards production goals. This paper introduces a novel methodology for approximating dynamic behaviour using artificial neural networks, rather than trying to determine exact representations. We suggest using neural networks in conjunction with traditional material flow simulation systems whenever a certain decision cannot be made ex ante in the model generation process due to insufficient knowledge about the behaviour of the real system. In such cases the decision is delegated to the neural network, which is connected to the simulation system at runtime. Training of the neural network is performed by observation of the real systems decision and based on the evaluation of data that can be gained through production data acquisition. Our approach has certain advantages compared to other approaches and is especially well suited in the context of on-line simulation and simulation-based operational decision support. We demonstrate the applicability of our methodology using a case study and report on performance results.
Meyer, Torben; Straßburger, Steffen
Integrierte virtuelle Inbetriebnahme : erhöhte Skalierbarkeit durch Integration von Materialfluss- und Anlagensimulation. - In: Werkstattstechnik, ISSN 1436-5006, Bd. 103 (2013), 3, S. 177-183

In den vergangenen Jahren hat sich die virtuelle Inbetriebnahme als Methode der "Digitalen Fabrik" zur Verkürzung der realen Inbetriebnahmezeit und zum Softwaretest einzelner Maschinen oder Anlagen etabliert. Eine weitere Methode der Digitalen Fabrik ist die Materialflusssimulation; sie untersucht ganze Fabriken beispielsweise hinsichtlich produktionslogistischer Fragestellungen. An einem Prototyp wurden die Potentiale und Herausforderungen dargestellt, die infolge der Verbindung von Materialflusssimulation und virtueller Inbetriebnahme entstehen.

Taylor, Simon J. E.; Turner, Stephen J.; Straßburger, Steffen; Mustafee, Navonil;
Bridging the gap: a standards-based approach to OR/MS distributed simulation. - In: ACM transactions on modeling and computer simulation, ISSN 1558-1195, Bd. 22 (2012), 4, S. 18:1-18:23

In Operations Research and Management Science (OR/MS), Discrete Event Simulation (DES) models are typically created using commercial off-the-shelf simulation packages (CSPs) such as AnyLogic, Arena, Flexsim, Simul8, SLX, Witness, and so on. A DES model represents the processes associated with a system of interest. Some models may be composed of submodels running in their own CSPs on different computers linked together over a communications network via distributed simulation software. The creation of a distributed simulation with CSPs is still complex and typically requires a partnership of problem owners, modelers, CSP vendors, and distributed simulation specialists. In an attempt to simplify this development and foster discussion between modelers and technologists, the SISO-STD-006-2010 Standard for COTS Simulation Package Interoperability Reference Models has been developed. The standard makes it possible to capture interoperability capabilities and requirements at a DES modeling level rather than a computing technical level. For example, it allows requirements for entity transfer between models to be clearly specified in DES terms (e.g. the relationship between departure and arrival simulation times and input element (queue, workstation, etc.), buffering rules, and entity priority, instead of using specialist technical terminology. This article explores the motivations for distributed simulation in this area, related work, and the rationale for the standard. The four Types of Interoperability Reference Model described in the standard are discussed and presented (A. Entity Transfer, B. Shared Resource, C. Shared Event, and D. Shared Data Structure). Case studies in healthcare and manufacturing are given to demonstrate how the standard is used in practice.
Wack, Karl-Josef; Riegmann, Tobias; Straßburger, Steffen; Guenther, Ulrich
Mehr Sicherheit in der Fertigung : virtuelle Produktionsabsicherung in der Montage. - In: Digital-Engineering-Magazin, ISSN 1618-002X, (2011), 5, S. 46-47

Automobilhersteller müssen in der Lage sein, kürzere Innovations- und Produktlebenszyklen zu realisieren, um wettbewerbsfähig zu bleiben. Zusätzlich führen unterschiedliche Kundenanforderungen zu einer großen Zahl an Produktvarianten - und so zu einer steigenden Anzahl an Serienanläufen. Effiziente Produktionsanläufe gewinnen daher mehr und mehr an Bedeutung. Die Methoden und Werkzeuge der digitalen Fabrik erlauben bereits frühzeitig eine virtuelle Absicherung der Montage.