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arXiv 2025年

作者： He, Hankun Boehringer, Takuya Schäfer, Benjamin Heppell, Kate Beck, Christian Centre for Complex Systems Queen Mary University of London United Kingdom University College London United Kingdom Institute for Automation and Applied Informatics Karlsruhe Institute of Technology Germany Chilterns National Landscape United Kingdom School of Geography Queen Mary University of London United Kingdom

By employing superstatistical methods and machine learning, we analyze time series data of water quality indicators for the River Thames (UK). The indicators analyzed include dissolved oxygen, temperature, electrical conductivity, pH, ammonium, turbidity, and rainfall, with a specific focus on the dynamics of dissolved oxygen. After detrending, the probability density functions of dissolved oxygen fluctuations exhibit heavy tails that are effectively modeled using q-Gaussian distributions. Our findings indicate that the multiplicative Empirical Mode Decomposition method stands out as the most effective detrending technique, yielding the highest log-likelihood in nearly all fittings. We also observe that the optimally fitted width parameter of the q-Gaussian shows a negative correlation with the distance to the sea, highlighting the influence of geographical factors on water quality dynamics. In the context of same-time prediction of dissolved oxygen, regression analysis incorporating various water quality indicators and temporal features identify the Light Gradient Boosting Machine as the best model. SHapley Additive exPlanations reveal that temperature, pH, and time of year play crucial roles in the predictions. Furthermore, we use the Transformer, a state-of-the-art machine learning model, to forecast dissolved oxygen concentrations. For long-term forecasting, the Informer model consistently delivers superior performance, achieving the lowest Mean Absolute Error and Symmetric Mean Absolute Percentage Error with the 192 historical time steps that we used. This performance is attributed to the Informer’s ProbSparse self-attention mechanism, which allows it to capture long-range dependencies in time-series data more effectively than other machine learning models. It effectively recognizes the half-life cycle of dissolved oxygen, with particular attention to critical periods such as morning to early afternoon, late evening to early morning, and key intervals between t

关键词： Aquatic ecosystems

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Mixed-Integer vs. Real-Valued Formulations of Battery Scheduling Problems

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IFAC-PapersOnLine 2018年第28期51卷 350-355页

作者： Murray, Alexander Faulwasser, Timm Hagenmeyer, Veit Institute for Automation and Applied Informatics Karlsruhe Institute of Technology Karlsruhe Germany

Coordinating the charging and discharging of a population of batteries with respect to load and generation forecasts decreases operating costs. However, in the case of asymmetric charging and discharging efficiencies the mathematical formulation of this problem is not straightforward. This paper compares the scheduling problem for a population of batteries in two formulations: mixed-integer (MINLP) and non-convex real-valued (NLP). In the case of the latter, the resulting separable NLP is solved using the Augmented Lagrangian based Alternating Direction Inexact Newton (ALADIN). In the case of the latter, the resulting MINLP is solved in hierarchical distributed fashion, we propose a mixed-integer extension of ALADIN. Real load and generation data is used to create an example of 54 batteries demonstrating improved performance for the MINLP formulation. © 2018

关键词： Charging (batteries) Constrained optimization Natural language processing systems Operating costs Scheduling Secondary batteries Standby power systems ALADIN Alternating directions Augmented Lagrangians Distributed optimization Generation forecast Mathematical formulation MINLP Scheduling problem

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Hierarchical Distributed Mixed-Integer Optimization for Reactive Power Dispatch

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IFAC-PapersOnLine 2018年第28期51卷 368-373页

作者： Murray, Alexander Engelmann, Alexander Hagenmeyer, Veit Faulwasser, Timm Institute for Automation and Applied Informatics Karlsruhe Institute of Technology Karlsruhe Germany

One key aspect of power system operation is the minimization of line losses while maintaining voltages within certain limits. Doing so can be achieved through the use of voltage regulators, tap changing transformers, and shunt capacitors. However, both tap changing transformers and/or shunt capacitors are operated in a discrete manner, i.e. the inputs can only take finitely many discrete values. Thus, the problem of minimizing line losses while maintaining voltage stability can be cast as a mixed-integer optimization problem. For large grids or cases where independent entities have concurrent control of the system, distributed optimization provides a solution. The present paper discusses a hierarchically distributed approach; i.e. the problem is partitioned into local subproblems and solved using a mixed-integer extension of the Augmented Lagrangian based Alternating Direction Inexact Newton (ALADIN) algorithm. We present results for the IEEE 14- and 30-bus systems and compare them with previous approaches, such as particle swarm optimization and genetic algorithms. © 2018

关键词： Electric load dispatching Concurrency control Constrained optimization Electric load flow Genetic algorithms Integer programming Particle swarm optimization (PSO) Reactive power Voltage regulators Alternating directions Distributed approaches Distributed optimization Mixed integer optimization Mixed integer problems Optimal power flows Power system operations Reactive power dispatch

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Simulation-Based Metrological Temperature Ensuring and Control of the Temperature Field in an Induction Furnace Based on Various Parameters

Simulation-Based Metrological Temperature Ensuring and Contr...

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International Conference on Computer and automation Engineering, ICCAE

作者： Jan Rybář Samuel Emebu Sayed Yousuf Sayed Sohaibullah Zarghoon Lukáš Bartalský Peter Onderčo Andrej Smetánka Radek Matušů Faculty of Mechanical Engineering Institute of Automation Informatization and Measurement Slovak University of Technology Bratislava Slovakia Department of Separation Science LUT School of Engineering Science Lappeenranta-Lahti University of Technology Lappeenranta Finland Department of Auto mechanical Engineering Faculty of Electro-Mechanic Kabul Polytechnic University Kabul Afghanistan Department of Automation and Control Engineering Faculty of Applied Informatics Tomas Bata University in Zlín Zlín Czech Republic

ISBN: (数字)9798331533816

ISBN: (纸本)9798331533823

Induction heating is widely used in industrial furnaces because of its rapid response time and high energy efficiency. To design and optimize these furnaces, computer-aided simulations are essential. This study aims to develop an accurate temperature field model for a square cross-section steel billet in an induction furnace by leveraging various parameters in COMSOL Multiphysics software. The simulation analysis incorporated temperature dynamics, considering skin depth, temperaturedependent, and constant parameters of the steel billet. The datadriven model was converted into a state-space representation utilizing MATLAB's System Identification Toolbox. This conversion facilitated the design of a Linear Quadratic Regulator (LQR) with integral gain and pole placement. Further, these controllers' performance was analyzed, and controllers were successfully implemented to regulate the temperature field of the billet from initial temperature to reference temperature, utilizing the distributed parameter system control circuit.

关键词： Billets Analytical models Temperature Accuracy Computational modeling Furnaces Mathematical models Temperature control Steel Induction heating

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Mask R-CNN Outperforms U-Net in Instance Segmentation for Overlapping Cells

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Current Directions in Biomedical Engineering 2023年第1期9卷 335-338页

作者： Rettenberger, Luca Rieken Münke, Friedrich Bruch, Roman Reischl, Markus Institute for Automation and Applied Informatics Karlsruhe Institute of Technology Eggenstein-Leopoldshafen Germany

U-Net is the go-to approach for biomedical segmentation applications. However, it is not designed to segment overlapping objects, a challenge Mask R-CNN has shown to have great potential in. Yet, Mask R-CNN receives little attention in biomedicine. Hence, we evaluate both approaches on a publicly available biomedical dataset. We find that Mask RCNN outperforms U-Net in segmenting overlapping cells and achieves comparable performance if they do not intersect. Our study provides valuable decision support to practitioners in selecting an appropriate method when solving instance segmentation tasks using deep learning, as well as important insights into enhancing the accuracy of such approaches in biomedical image analysis. © 2023 the author(s), published by Walter de Gruyter Berlin/Boston.

关键词： Computer vision

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Prediction of selected production goals by classification methods

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applied Mechanics and Materials 2014年 474卷 115-120页

作者： Jurovata, Dominika Vazan, Pavel Kebisek, Michal Tanuska, Pavol Hrčka, Lukáš Institute of Applied Informatics Automation and Mathematics Slovak University of Technology in Bratislava Slovakia

ISBN: (纸本)9783037859445

The goal of this work was to use the process of knowledge discovery in planning and control of production processes. This work is focused on the prediction of the system behavior from the data of production process. The classification was used as a task of data mining. Some predictive models were created and the predictions of the production process behavior were realized by varying the input parameters using selected methods and techniques of data mining. It can be confirmed that the selected input parameters will lead to the fulfillment of the declared objectives of the process. The process of knowledge discovery has been implemented in the program STATISTICA Data Miner. © (2014) Trans Tech Publications, Switzerland.

关键词： Forecasting

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Assignment of labour to a production line depending on lot size

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applied Mechanics and Materials 2014年 474卷 121-126页

作者： Kurnátová, Júlia Važan, Pavel Križanová, Gabriela Orihelová, Katarína Institute of Applied Informatics Automation and Mathematics Slovak University of Technology in Bratislava Slovakia

ISBN: (纸本)9783037859445

The paper describes the results of real simulation project in production line. The aim was to optimize the number of workers according to the different orders during one working week, to minimize time for orders realization with using the alternative technological processes, to minimize the length of order processing at maximum the number of workers on the shift. The simulation optimization was used for solution finding. © (2014) Trans Tech Publications, Switzerland.

关键词： Mechanics

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Reflection on boon and bane of water absorbing components in active implants during package testing and operation

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Current Directions in Biomedical Engineering 2018年第1期4卷 319-322页

作者： Koker, Liane Gengenbach, Ulrich Bretthauer, Georg Institute for Automation and Applied Informatics (IAI) Karlsruhe Institute of Technology (KIT) Karlsruhe Germany

For package testing of active implants internal humidity measurements are performed. Thereby, the water absorbency of the measurement components can affect the measurement result, leading to an erroneously prolonged predicted lifetime. Here, the infuence of internal components is discussed using an exemplary setup. It is described how to model and consider the components' absorbencies for lifetime estimation and how beneficial they are during implant operation. © 2018 Liane Koker et al.

关键词： Humidity sensors

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Application of Model-Free Control to Reduce the Total Harmonic Distortion of Inverters 8

Application of Model-Free Control to Reduce the Total Harmon...

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8th IEEE Workshop on the Electronic Grid, eGRID 2023

作者： Wachter, Jan Groll, Lutz Hagenmeyer, Veit Institute for Automation and Applied Informatics Karlsruhe Germany

ISBN: (纸本)9798350327007

With the fast rising number of power electronic devices in the electric grid, the harmonic emissions of those devices can lead to significant power quality issues. This is reflected in the recent addition of harmonic stability as one of the grid stability types. The reduction of harmonic emissions is an important task in the development of resilient carbon neutral grids. This paper describes the application of the model-free control concept for grid-Tied inverters as an easily implementable extension for dq0-frame based current control loops, which are often used in cascaded control schemes. The approach incorporates the information contained in the output current derivative. To balance phase-error and measurement noise suppression, the derivative is obtained using an algebraic numerical differentiator. The reduction of the total harmonic distortion (THD) is demonstrated for two use-cases in simulation, in order to show the transferability of the results. Further, measurement data from a hardware implementation of the concept is studied to verify the behavior under real-world conditions. For this, the influence of the tuning parameters is discussed along with limitations of the approach. © 2023 IEEE.

关键词： Power quality

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Real-time State Estimation for an Adaptive Vibration Energy Harvesting System

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IFAC-PapersOnLine 2016年第25期49卷 127-132页

作者： Abdollahpouri, Mohammad Gulan, Martin Takács, Gergely Rohal'-Ilkiv, Boris Slovak University of Technology in Bratislava Faculty of Mechanical Engineering Institute of Automation Measurement and Applied Informatics Slovakia

Moving horizon estimation (MHE) has proven to be an efficient optimization-based technique to address the problem of joint state and parameter estimation with nonlinearities in system dynamics and constraints. This work aims to propose the application of MHE for a specific nonlinear vibration setup, often used to analyze energy harvesting concepts in the laboratory environment. Using a simulated energy harvesting scenario exhibiting a strongly nonlinear behavior, we focus on the estimation of unmeasured system states and a time-varying structural parameter that can be utilized to maximize the harvested energy, or in structural health monitoring. To exploit the recent algorithmic developments in embedded optimization, we implement the proposed scheme on a low-cost embedded computing platform using automatic code generation. A hardware-in-the-loop setup is used in order to investigate the performance of the real-time MHE scheme, and to quantify the associated computational effort. The results demonstrated in this paper, suggest the real-time feasibility of MHE, and certain practical advantages over a standard Kalman filtering in a vibration energy harvesting system. © 2016

关键词： Parameter estimation Automatic programming Cantilever beams Embedded systems Energy harvesting Structural health monitoring Vibration analysis Automatic code generations Duffing oscillator Embedded optimizations Moving horizon estimation Optimization based techniques State and parameter estimations Time varying structural parameters Vibration energy harvesting

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