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Real-time model calibration with deep reinforcement learning
(2022)Mechanical Systems and Signal ProcessingThe real-time, and accurate inference of model parameters is of great importance in many scientific and engineering disciplines that use computational models (such as a digital twin) for the analysis and prediction of complex physical processes. However, fast and accurate inference for processes of complex systems cannot easily be achieved in real-time with state-of-the-art methods under noisy real-world conditions with the requirement ...Journal Article -
The evolution of roles
(2022)Social NetworksWe propose a novel formalization of roles in social networks that unifies the most commonly used definitions of role equivalence. As one consequence, we obtain a single, straightforward proof that role equivalences form lattices. Our formalization focuses on the evolution of roles from arbitrary initial conditions and thereby generalizes notions of relative and iterated roles that have been suggested previously. In addition to the unified ...Journal Article -
Learning Q-function approximations for hybrid control problems
(2022)IEEE Control Systems LettersThe main challenge in controlling hybrid systems arises from having to consider an exponential number of sequences of future modes to make good long-term decisions. Model predictive control (MPC) computes a control action through a finite-horizon optimisation problem. A key ingredient in this problem is a terminal cost, to account for the system’s evolution beyond the chosen horizon. A good terminal cost can reduce the horizon length ...Journal Article -
A System Level Approach to Tube-based Model Predictive Control
(2022)IEEE Control Systems LettersRobust tube-based model predictive control (MPC) methods address constraint satisfaction by leveraging an a priori determined tube controller in the prediction to tighten the constraints. This letter presents a system level tube-MPC (SLTMPC) method derived from the system level parameterization (SLP), which allows optimization over the tube controller online when solving the MPC problem, which can significantly reduce conservativeness. ...Journal Article -
Parametric reduced order models for output-only vibration-based crack detection in shell structures
(2022)Mechanical Systems and Signal ProcessingJournal Article -
Fusing physics-based and deep learning models for prognostics
(2022)Reliability Engineering & System SafetyPhysics-based and data-driven models for remaining useful lifetime (RUL) prediction typically suffer from two major challenges that limit their applicability to complex real-world domains: (1) the incompleteness of physics-based models and (2) the limited representativeness of the training dataset for data-driven models. Combining the advantages of these two approaches while overcoming some of their limitations, we propose a novel hybrid ...Journal Article -
Process design within planetary boundaries: Application to CO2 based methanol production
(2021)Chemical Engineering ScienceDesigning sustainable processes is gaining momentum in the chemical engineering community. Conventional life cycle assessment approaches often employed to assess the sustainability level of chemical processes can be used to compare alternatives. However, because they lack clear quantitative thresholds above which a process should be deemed unsustainable, the insight provided into whether a technology is truly sustainable in absolute terms ...Journal Article -
Understanding the interaction of organic corrosion inhibitors with copper at the molecular scale: Benzotriazole on Cu(110)
(2021)Applied Surface ScienceBenzotriazole (BTAH) has been used for several industrial applications, but most commonly as a corrosion inhibitor for copper, since the 1950s. However, the mechanism of its interaction with copper surfaces at the atomistic scale is still a matter of debate. Here, the adsorption of BTAH onto a clean Cu(110) surface has been investigated by a combination of scanning tunnelling microscopy, X-ray photoelectron spectroscopy, high resolution ...Journal Article -
Seasonal variation in sleep homeostasis in migratory geese: a rebound of NREM sleep following sleep deprivation in summer but not in winter
(2021)SleepSleep is a behavioral and physiological state that is thought to serve important functions. Many animals go through phases in the annual cycle where sleep time might be limited, for example, during the migration and breeding phases. This leads to the question whether there are seasonal changes in sleep homeostasis. Using electroencephalogram (EEG) data loggers, we measured sleep in summer and winter in 13 barnacle geese (Branta leucopsis) ...Journal Article -
Price-region bids in electricity markets
(2021)European Journal of Operational ResearchCurrent bid formats in pool-based electricity markets are ill-equipped to accommodate the broad range of non-conventional sources of flexibility, such as demand response and interconnected heating, natural gas and water infrastructure networks. To address this issue, this paper introduces the novel price-region bid format to be used in both forward electricity markets and financial right auctions. We show that price-region bids are able ...Journal Article