Refine
Document Type
- Preprint (7) (remove)
Has Fulltext
- yes (7)
Keywords
- 3D Printing (2)
- Combined simulation (2)
- Optimierung (2)
- Simulation (2)
- 3D-Druck (1)
- Adaptive Schrittweite (1)
- Angewandte Mathematik (1)
- Biogas (1)
- Biogas Plant (1)
- Board Games (1)
In 2021 feiert die Technische Hochschule Köln (TH Köln) ihr 50-jähriges Jubiläum und damit auch das Institut für Versicherungswesen (ivwKöln), wobei sich inzwischen Forschung, Lehre und Transfer in die Praxis auf alle Risikofelder des Versicherungsgeschäfts und alle Kompetenzbereiche der Versicherungsunternehmen beziehen. Anlässlich dieses Jubiläums hat das ivwKöln daher in einem Band „Risiko im Wandel. Herausforderung für die Versicherungswirtschaft“, der in 2022 als Open Access erscheinen wird, die Vielfalt von Forschung und Praxis aller Mitwirkenden an der Arbeit des Institutes gebündelt zusammengefasst. Der nachfolgende Beitrag soll schon vorab einen Überblick der verschiedenen Forschungsthemen geben.
Increasing computational power and the availability of 3D printers provide new tools for the combination of modeling and experimentation. Several simulation tools can be run independently and in parallel, e.g., long running computational fluid dynamics simulations can be accompanied by experiments with 3D printers. Furthermore, results from analytical and data-driven models can be incorporated. However, there are fundamental differences between these modeling approaches: some models, e.g., analytical models, use domain knowledge, whereas data-driven models do not require any information about the underlying processes.
At the same time, data-driven models require input and output data, but analytical models do not. Combining results from models with different input-output structures might improve and accelerate the optimization process. The optimization via multimodel simulation (OMMS) approach, which is able to combine results from these different models, is introduced in this paper.
Using cyclonic dust separators as a real-world simulation problem, the feasibility of this approach is demonstrated and a proof-of-concept is presented. Cyclones are popular devices used to filter dust from the emitted flue gases. They are applied as pre-filters in many industrial processes including energy production and grain processing facilities. Pros and cons of this multimodel optimization approach are discussed and experiences from experiments are presented.
Forschendes Lernen versteht sich als ein methodisches Prinzip, das Forschungsorientierung und Verknüpfung von Forschung und Lehre in die Studiengänge und Lehrveranstaltungen integriert und für studentische Lernprozesse nutzbringend anwendet. Studierende sind dabei Teil der Scientific Community.
Dieser Artikel ist ein Erfahrungsbericht, in dem das Konzept des „Forschenden Lernens“ in einer Variante vorgestellt wird, die in den letzten zehn Jahren an einer deutschen Fachhochschule für ingenieurwissenschaftliche Studiengänge entwickelt wurde.
Da es „das“ Forschende Lernen nicht gibt, werden zunächst die für diesen Artikel relevanten Gesichtspunkte zusammengestellt. Darauf aufbauend wird ein Prozessmodell des Forschenden Lernens vorgestellt. Dieses Modell ermöglicht Forschendes Lernen für Bachelor- und Masterstudierende sowie für Doktorandinnen und Doktoranden.
Cyclone separators are popular devices used to filter dust from the emitted flue gases. They are applied as pre-filters in many industrial processes including energy production and grain processing facilities.
Increasing computational power and the availability of 3D printers provide new tools for the combination of modeling and experimentation, which necessary for constructing efficient cyclones. Several simulation tools can be run in parallel, e.g., long running CFD simulations can be accompanied by experiments with 3D printers. Furthermore, results from analytical and data-driven models can be incorporated. There are fundamental differences between these modeling approaches: some models, e.g., analytical models, use domain knowledge, whereas data-driven models do not require any information about the underlying processes.
At the same time, data-driven models require input and output data, whereas analytical models do not. Combining results from models with different input-output structure is of great interest. This combination inspired the development of a new methodology. An optimization via multimodel simulation approach, which combines results from different models, is introduced.
Using cyclonic dust separators (cyclones) as a real-world simulation problem, the feasibility of this approach is demonstrated. Pros and cons of this approach are discussed and experiences from the experiments are presented.
Furthermore, technical problems, which are related to 3D-printing approaches, are discussed.
Computational intelligence methods have gained importance in several real-world domains such as process optimization, system identification, data mining, or statistical quality control. Tools are missing, which determine the applicability of computational intelligence methods in these application domains in an objective manner. Statistics provide methods for comparing algorithms on certain data sets. In the past, several test suites were presented and considered as state of the art. However, there are several drawbacks of these test suites, namely: (i) problem instances are somehow artificial and have no direct link to real-world settings; (ii) since there is a fixed number of test instances, algorithms can be fitted or tuned to this specific and very limited set of test functions; (iii) statistical tools for comparisons of several algorithms on several test problem instances are relatively complex and not easily to analyze. We propose amethodology to overcome these dificulties. It is based on standard ideas from statistics: analysis of variance and its extension to mixed models. This work combines essential ideas from two approaches: problem generation and statistical analysis of computer experiments.
Learning board games by self-play has a long tradition in computational intelligence for games. Based on Tesauro’s seminal success with TD-Gammon in 1994, many successful agents use temporal difference learning today. But in order to be successful with temporal difference learning on game tasks, often a careful selection of features and a large number of training games is necessary. Even for board games of moderate complexity like Connect-4, we found in previous work that a very rich initial feature set and several millions of game plays are required. In this work we investigate different approaches of online-adaptable learning rates like Incremental Delta Bar Delta (IDBD) or Temporal Coherence Learning (TCL) whether they have the potential to speed up learning for such a complex task. We propose a new variant of TCL with geometric step size changes. We compare those algorithms with several other state-of-the-art learning rate adaptation algorithms and perform a case study on the sensitivity with respect to their meta parameters. We show that in this set of learning algorithms those with geometric step size changes outperform those other algorithms with constant step size changes. Algorithms with nonlinear output functions are slightly better than linear ones. Algorithms with geometric step size changes learn faster by a factor of 4 as compared to previously published results on the task Connect-4.
An essential task for operation and planning of biogas plants is the optimization of substrate feed mixtures. Optimizing the monetary gain requires the determination of the exact amounts of maize, manure, grass silage, and other substrates. Accurate simulation models are mandatory for this optimization, because the underlying chemical processes are very slow. The simulation models themselves may be time-consuming to evaluate, hence we show how to use surrogate-model-based approaches to optimize biogas plants efficiently. In detail, a Kriging surrogate is employed. To improve model quality of this surrogate, we integrate cheaply available data into the optimization process. Doing so, Multi-fidelity modeling methods like Co-Kriging are employed. Furthermore, a two-layered modeling approach is employed to avoid deterioration of model quality due to discontinuities in the search space. At the same time, the cheaply available data is shown to be very useful for initialization of the employed optimization algorithms. Overall, we show how biogas plants can be efficiently modeled using data-driven methods, avoiding discontinuities as well as including cheaply available data. The application of the derived surrogate models to an optimization process is shown to be very difficult, yet successful for a lower problem dimension.