Publikationen

2021

• Adapting Behavior Driven Development (BDD) for large-scale software systems

  Irshad, M., Britto, R., & Petersen, K. (2021). Adapting Behavior Driven Development (BDD) for large-scale software systems. Journal of Systems and Software, 177, 110944.

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    • Petersen, Kai

  • Abteilung/Einrichtung

    • FLAIR - Flensburg Artificial Intelligence Research

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  • 2021
  • Journal Article
  • • Mohsin Irshad
    • Ricardo Britto
    • Kai Petersen

• Delegating Supersingular Isogenies over F_p^2 with Cryptographic Applications

  Pedersen, R., & Uzunkol, O. (2021). Delegating Supersingular Isogenies over F_p^2 with Cryptographic Applications. IACR Cryptol. ePrint Arch., 2021, 506. Abgerufen von https://eprint.iacr.org/2021/506

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  • Personenseiten

    • Uzunkol, Osmanbey

  • Fachbereich

    • Fachbereich 3: Information und Kommunikation

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  • 2021
  • Journal Article
  • • Robi Pedersen
    • Osmanbey Uzunkol

• Implementation of Variable Blade Inertia in OpenFAST to Integrate a Flywheel System in the Rotor of a Wind Turbine

  Alhrshy, L. (2021). Implementation of Variable Blade Inertia in OpenFAST to Integrate a Flywheel System in the Rotor of a Wind Turbine. Energies, 14. http://doi.org/10.3390/en14102783

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  In this paper, the integration of the dynamic behavior of the flywheel system into the load simulation tool OpenFAST is presented. The flywheel system enables a wind turbine to vary the inertia of its rotor blades to control the power production and, most importantly, to affect the vibratory behavior of wind turbine components. Consequently, in order to simulate the behavior of a wind turbine with a flywheel system in its rotor, the variable blade characteristics need to be considered in the load simulation tool. Currently, computer-aided engineering tools for simulating the mechanical loads of wind turbines are not designed to simulate variable blade inertia. Hence, the goal of this paper is to explain how variable inertias of rotor blades are implanted in such load simulation tools as OpenFAST. OpenFAST is used because of it is free, publicly available, and well documentation. Moreover, OpenFAST is open source, which allows modifications in its source code. This add-on in the load simulation is applied to correct rotor mass imbalance. It can also be applied in many cases related to the change in the inertia of wind turbine rotor blades during its operation as, for example, atmospheric ice accretion on the blades, smart blades, etc.

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    • Alhrshy, Laurence

  • Forschungsprojekt

    • Schwungrad

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

  • Fachbereich

    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Laurence Alhrshy

• Grid Support with Wind Turbines: The Case of the 2019 Blackout in Flensburg

  Gloe, A., Jauch, C., & Räther, T. (2021). Grid Support with Wind Turbines: The Case of the 2019 Blackout in Flensburg. Energies, 14(6), 1697. http://doi.org/10.3390/en14061697

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  The work presented in this paper aims to show how modern wind turbines can help to control the frequency in a small grid which suffers from large power imbalances. It is shown for an exemplary situation, which occurred in Flensburg’s distribution grid in 2019: a major blackout, which occurred after almost two hours in islanding operation, affecting almost the entire distribution grid, which supplies approximately 55,000 households and businesses. For the analysis, a wind turbine model and a grid support controller developed at the Wind Energy Technology Institute are combined with real measurements from the day of the blackout to generate a fictional yet realistic case study for such an islanding situation. For this case study, it is assumed that wind turbines with grid support functionalities are connected to the medium voltage distribution grid of the city. It is shown to what extent wind turbines can help to operate the grid by providing grid frequency support in two ways: By supplying synthetic inertia only, where the wind turbines can help to limit the rate of change of frequency in the islanded grid directly after losing the connection to the central European grid. In combination with the primary frequency control capabilities of the wind turbines (WTs), the disconnection of one gen set in the local power station might have been avoided. Furthermore, wind turbines with primary frequency control capabilities could have restored the grid frequency to 50 Hz shortly after the islanding situation even if the aforementioned gen-set was lost. This would have allowed connecting a backup medium voltage line to the central European grid and thereby avoiding the blackout.

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    • Gloe, Arne
    • Jauch, Clemens

  • Forschungsprojekt

    • Grenzland INNOVATIV Schleswig-Holstein

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

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  • 2021
  • Journal Article
  • • Arne Gloe
    • Prof. Dr. Clemens Jauch
    • Thomas Räther
  • • WETI

• Feature selection techniques for modelling tower fatigue loads of a wind turbine with neural networks

  Movsessian, A., Schedat, M., & Faber, P. D.-I. T. (2021). Feature selection techniques for modelling tower fatigue loads of a wind turbine with neural networks. Wind Energy Science. http://doi.org/https://doi.org/10.5194/wes-6-539-2021

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    • Faber, Torsten

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

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  • 2021
  • Journal Article
  • • A. Movsessian
    • M. Schedat
    • Prof. Dr.-Ing. Torsten Faber
  • • WETI

• Influence of Continuous Provision of Synthetic Inertia on the Mechanical Loads of a Wind Turbine

  Gloe, A., Jauch, C., Craciun, B., Zanter, A., & Winkelmann, J. (2021). Influence of Continuous Provision of Synthetic Inertia on the Mechanical Loads of a Wind Turbine. Energies, 14(16), 5185. http://doi.org/10.3390/en14165185

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  In many electrical grids, the share of renewable energy generation increases. As these generators are typically connected to the grid via inverters, the level of grid inertia decreases. Such grids may therefore suffer from high rates of change of frequency during power imbalances. Modern wind turbines can help in controlling the frequency in such grids by providing synthetic inertia. A controller to provide synthetic inertia with wind turbines was developed at the Wind Energy Technology Institute in collaboration with Suzlon Energy. For this controller the influence of providing synthetic inertia on the mechanical loads of the wind turbine is assessed for different grid frequency scenarios. Such a scenario-based load analysis has not been published before, especially as the scenarios are derived from real measurements. The effect of the loads strongly depends on the analyzed grid frequency behavior. Ten months of high quality grid frequency measurements of the Indian grid are analyzed in order to derive inputs for the load calculation. Different types of grid frequency abnormities are identified and categorized with respect to their severity. Based on the observed occurrences of the grid frequency abnormities, realistic scenarios for the load calculations are chosen. The load calculations are performed for a state-of-the-art Suzlon wind turbine generator. The load increases caused by the supply of synthetic inertia are calculated for individual components assuming an otherwise undisturbed power production of the wind turbine in turbulent wind. Furthermore, a hardware-in-the-loop test bench is used to show how the measured grid frequencies are actually perceived by the control system of a typical wind turbine. The original frequency data were recorded with high quality measurement equipment, which is faster and more accurate than a multi-function relay, often used in wind turbines. For exemplary time traces, the effect of the reduced measurement accuracy on the reaction of the wind turbine is shown. This aspect has not been investigated in the literature yet. The results show that wind turbines can provide synthetic inertia without a considerable effect on the lifetime of the wind turbine. However, there are still problems with providing synthetic inertia reliably at high power operating points, which have to be solved.

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    • Gloe, Arne
    • Jauch, Clemens

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

  • Fachbereich

    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Arne Gloe
    • Prof. Dr. Clemens Jauch
    • B. Craciun
    • Arvid Zanter
    • J. Winkelmann
  • • WETI

• Towards evidence-based decision-making for identification and usage of assets in composite software: A research roadmap

  Wohlin, C., Papatheocharous, E., Carlson, J., Petersen, K., egroth, E. A., Axelsson, J., … others,. (2021). Towards evidence-based decision-making for identification and usage of assets in composite software: A research roadmap. Journal of Software: Evolution and Process, 33, e2345.

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    • Petersen, Kai

  • Abteilung/Einrichtung

    • FLAIR - Flensburg Artificial Intelligence Research

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  • 2021
  • Journal Article
  • • Claes Wohlin
    • Efi Papatheocharous
    • Jan Carlson
    • Kai Petersen
    • Emil egroth
    • Jakob Axelsson
    • Deepika Badampudi
    • Markus Borg
    • Antonio Cicchetti
    • Federicio Ciccozzi
    • others

• Exploration vs. limitation – An investigation of instructional design techniques for spatial ability training on mobile devices

  Montag, M., Bertel, S., de Koning, B. B., & Zander, S. (2021). Exploration vs. limitation – An investigation of instructional design techniques for spatial ability training on mobile devices. Computers in Human Behavior, 118, 106678. http://doi.org/https://doi.org/10.1016/j.chb.2020.106678

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  Spatial abilities and thus mental rotation skills predict achievement in STEM domains. Thus, a wide range of studies investigated the possibilities and trainings of mental rotation skills. One prominent approach is using different digital tools and representation formats to foster spatial abilities. Thereby numerous studies analyzed effects of static in comparison to interactive dynamic representations of mental rotation tasks using different types of interactions. Although the use of dynamic representations is discussed critical regarding superficial information processing, there are no studies to date varying instructional techniques in interactive dynamic spatial trainings. In two studies we compared Limited Rotation training to non-limited Free Rotation training with high school students (Npilot = 21, Nmain = 66). Results after training show a superior effect of the limited compared to the non-limited training regarding the students’ success rate, but not their motivation and mental demand. Additionally analyzed process data show more efficient ways of task solving after limited rotation training indicated by reduced response time and rotation way accompanied by higher success rates in solving non-limited rotation tasks. Results of a pre-and-post-comparison of mental rotation skills indicate a higher increment after limited rotation training. Over-facilitating effects of dynamic representations are discussed.

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    • Bertel, Sven

  • Abteilung/Einrichtung

    • CIVU – Center for Interaction, Visualization and Usability

  • Fachbereich

    • Fachbereich 3: Information und Kommunikation

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  • 2021
  • Journal Article
  • • Michael Montag
    • Sven Bertel
    • Bjorn de Koning
    • Steffi Zander
  • • Spacial abilities
    • STEM
    • Multimedia learning
    • mental rotation

• Does it pay for new firms to be green? An empirical analysis of when and how different greening strategies affect the performance of new firms

  Neumann, T. (2021). Does it pay for new firms to be green? An empirical analysis of when and how different greening strategies affect the performance of new firms. Journal of Cleaner Production, 317, 128403. http://doi.org/https://doi.org/10.1016/j.jclepro.2021.128403

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  Despite the significant attention devoted to the impact of corporate greening strategies on firm performance, research has so far focused on established firms, leaving the situation in new firms unclear. In this study, it is hypothesised that the impact of greening strategies on the performance of new firms depends on the type of strategy, and that the firm s age positively moderates this impact. Using a cross-sectoral dataset of 11,039 new firms from 36 countries, binary and ordinal logistic regressions were estimated for different start-up phases. The results indicate that new firms benefit from substantive greening strategies but, contrary to expectations, not from symbolic greening strategies. The performance of new firms in their later start-up phases was even found to be harmed if they adopt symbolic strategies but do not reinforce them with substantive actions (green-washing). No impact, or only a weakly positive impact was found for firms adopting both substantive and symbolic greening strategies (green-highlighting) or only substantive ones (brown-washing). Furthermore, the interaction analyses did not reveal any moderating effects of firm age, but additional investigation shows that the impacts of greening strategies do differ between age groups. Finally, robustness tests reveal that the relationship between substantive greening strategies and the performance of new firms is not linear but decreases with increasing environmental efforts.

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  • Forschungsprojekt

    • StartUP SH

  • Abteilung/Einrichtung

    • Jackstädt-Zentrum Flensburg (JZF)

  • Fachbereich

    • Fachbereich 4: Wirtschaft

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  • 2021
  • Journal Article
  • • Thomas Neumann
  • • Entrepreneurship
    • Start-up
    • Substantive vs symbolic greening
    • Greenwashing
    • Brownwashing
    • Age

• Apps und webbasierte Interventionen in der Prostatakrebsnachsorge – ein Scoping Review

  Pornak, S. C., Papachrysanthou, A., & Lehr, B. (2021). Apps und webbasierte Interventionen in der Prostatakrebsnachsorge – ein Scoping Review. Der Urologe, 60, 911–920.

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    • Pornak, Shirin Caroline

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  • 2021
  • Journal Article
  • • Shirin Pornak
    • Anna Papachrysanthou
    • Bosco Lehr