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arXiv 2023年

作者： Mark, Christoph Liu, Steven Institute of Control Systems Department of Electrical and Computer Engineering University of Kaiserslautern-Landau Kaiserslautern67663 Germany

In this paper, we develop a distributionally robust model predictive control framework for the control of wind farms with the goal of power tracking and mechanical stress reduction of the individual wind turbines. We introduce an ARMA model to predict the turbulent wind speed, where we merely assume that the residuals are sub-Gaussian noise with statistics contained in an moment-based ambiguity set. We employ a recently developed distributionally model predictive control scheme to ensure constraint satisfaction and recursive feasibility of the control algorithm. The effectiveness of the approach is demonstrated on a practical example of five wind turbines in a row. © 2023, CC BY-NC-ND.

关键词： Wind turbines

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Bio-Orthogonally Double Cross-Linked Alginate-Gelatin Hydrogels with Tunable Viscoelasticity for Cardiac Tissue engineering

SSRN

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SSRN 2025年

作者： Testore, Daniele Zoso, Alice Paoletti, Camilla Groppo, Sara Marcello, Elena Chiono, Valeria Department of Mechanical and Aerospace Engineering Politecnico di Torino Turin Italy Polito BIOMedLab Politecnico di Torino Torino Italy Department of Control and Computer Engineering Politecnico di Torino Turin Italy

Growing evidence has shown that cells respond to the viscoelastic properties of the extracellular matrix (ECM), particularly its stress-relaxation, which influences their spreading, proliferation, and remodeling. Since cardiac tissue viscoelasticity plays a key role in modulating cellular mechanosensing, the development of biomimetic viscoelastic hydrogels is highly needed in cardiac tissue engineering (CTE). This work presents bio-orthogonal double cross-linked alginate-gelatin hydrogels with tunable viscoelasticity, designed to replicate the dynamic mechanical properties of cardiac ECM. Alginate and gelatin were functionalized with azide groups and cross-linked by a 4-arm-dibenzocyclooctyne (DBCO) crosslinker using strain-promoted azide-alkyne cycloaddition (SPAAC) with 0.5:1 (AG_Click(R0.5)) and 1:1 (AG_Click(R1)) DBCO:azide molar ratios. Calcium ions were also introduced to obtain double cross-linked hydrogels (AG_DC(R0.5) and AG_DC(R1)). Rheology showed that hydrogels exhibited tunable stiffness and stress relaxation, closely mimicking the properties of native cardiac tissue. The behavior of human cardiac fibroblasts (HCFs), seeded on hydrogels, was analyzed. When compared to purely elastic polyacrylamide (pAAm) hydrogels with comparable stiffness, soft stress-relaxing hydrogels (AG_Click(R0.5) and AG_DC(R0.5)) were found to promote cell spreading area, while stiffer stress-relaxing hydrogels (AG_Click(R1) and AG_DC(R1)) enhanced asymmetric cell elongation, reflecting substrate-mediated mechanosensing. Additionally, HCFs showed high viability when cultured in 3D hydrogels over 7 days. Overall, rapid gelation, biocompatibility, and tunable viscoelastic properties of bio-orthogonal double cross-linked alginate-gelatin hydrogels support their use as injectable formulations or engineered cardiac tissues for CTE. © 2025, The Authors. All rights reserved.

关键词： Cell signaling

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Multiphase LLC Resonant Converter with Natural Current Sharing and Phase-Shedding

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IEEE Transactions on Industry Applications 2025年

作者： Ahmad, Ubaid Giral, Roberto Olalla, Carlos Sangwongwanich, Ariya Davari, Pooya Blaabjerg, Frede Universitat Rovira i Virgili Països Catalans Department of Electrical Electronics and Automatic Control Engineering School of Electrical and Computer Engineering Catalonia Tarragona26 43007 Spain Aalborg University Department of Energy Aalborg Ost9220 Denmark

The multiphase LLC converter is commonly used for high-power and high step-down applications. However, the tolerances in the tank circuit parameters cause uneven current sharing (CS), reducing system reliability. Additionally, phase-shedding (PS) can improve converter efficiency at partial load by turning-OFF phases. This paper proposes a multiphase input-parallel output-parallel LLC resonant converter with a common inductor-capacitor branch, with the objective to achieve excellent CS and phase-shedding at the same time. Thanks to the shared branch, current-sharing is natural, and phase-shedding is realized without affecting the operating point. With fewer passive comp- onents and a simple phase connection, the design offers low-cost, high-power density, and improved light-load efficiency compared to existing solutions. Detailed analysis shows improved CS on both the primary and secondary sides, when compared to previous approaches. Simulation and experimental results for the proposed two-phase LLC resonant converter validate the analysis and illustrate the effectiveness of the CS and PS capabilities. At the rated load of 800 W, CS error is 2.48% on the primary side and 2.0% on the secondary side. Phase-shedding improves efficiency by 3.60% at 50% load and 6.82% at 25% load. © 1972-2012 IEEE.

关键词： Resonant converters

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Manipulation of Elasto-Flexible Cables with Single or Multiple UAVs

arXiv

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arXiv 2025年

作者： Gabellieri, Chiara Teeuwen, Lars Shen, Yaolei Franchi, Antonio Faculty University of Twente Enschede7500 AE Netherlands Department of Computer Control and Management Engineering Sapienza University of Rome Rome00185 Italy

This work considers a large class of systems composed of multiple quadrotors manipulating deformable and extensible cables. The cable is described via a discretized representation, which decomposes it into linear springs interconnected through lumped-mass passive spherical joints. Sets of flat outputs are found for the systems. Numerical simulations support the findings by showing cable manipulation relying on flatness-based trajectories. Eventually, we present an experimental validation of the effectiveness of the proposed discretized cable model for a two-robot example. Moreover, a closed-loop controller based on the identified model and using cable-output feedback is experimentally tested. © 2025, CC BY.

关键词： Closed loop control systems

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Optimisation-Based Iterative Learning control for Distributed Consensus Tracking

Optimisation-Based Iterative Learning Control for Distribute...

引用

UKACC International Conference on control (control)

作者： Yueqing Zhang Bin Chen Bing Chu Zhan Shu Faculty of Engineering and Physical Sciences University of Southampton Southampton Department of Automatic Control and Systems Engineering University of Sheffield Sheffield U.K. Department of Electrical and Computer Engineering University of Alberta Edmonton Canada

ISBN: (数字)9798350374261

ISBN: (纸本)9798350374278

This paper addresses high-performance consensus tracking of repetitively operating networked dynamical systems using an iterative learning control (ILC) algorithm. It circumvents the need for precise model information in traditional methods and guarantees the high-performance by the predictive framework with a novel performance index that takes into account both current and future performance. The proposed algorithm ensures geometric convergence of the tracking error norm to zero and can be applied to both heterogeneous and non-minimum-phase systems. A distributed implementation of the algorithm is developed using the Alternating Direction Method of Multipliers, with detailed convergence analysis and numerical examples confirming its effectiveness.

关键词： System dynamics Heuristic algorithms Scholarships Predictive models Prediction algorithms Performance analysis Reliability

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IT'S ALL IN THE EMBEDDING! FAKE NEWS DETECTION USING DOCUMENT EMBEDDINGS

arXiv

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arXiv 2023年

作者： Truicǎ, Ciprian-Octavian Apostol, Elena-Simona Computer Science and Engineering Department Faculty of Automatic Control and Computers University Politehnica of Bucharest Bucharest Romania

With the current shift in the mass media landscape from journalistic rigor to social media, personalized social media is becoming the new norm. Although the digitalization progress of the media brings many advantages, it also increases the risk of spreading disinformation, misinformation, and malformation through the use of fake news. The emergence of this harmful phenomenon has managed to polarize society and manipulate public opinion on particular topics, e.g., elections, vaccinations, etc. Such information propagated on social media can distort public perceptions and generate social unrest while lacking the rigor of traditional journalism. Natural Language Processing and Machine Learning techniques are essential for developing efficient tools that can detect fake news. Models that use the context of textual data are essential for resolving the fake news detection problem, as they manage to encode linguistic features within the vector representation of words. In this paper, we propose a new approach that uses document embeddings to build multiple models that accurately label news articles as reliable or fake. We also present a benchmark on different architectures that detect fake news using binary or multi-labeled classification. We evaluated the models on five large news corpora using accuracy, precision, and recall. We obtained better results than more complex state-of-the-art Deep Neural Network models. We observe that the most important factor for obtaining high accuracy is the document encoding, not the classification model's complexity. © 2023, CC BY-NC-ND.

关键词： Embeddings

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State-Space Piece-Wise Affine System Identification with Online Deterministic Annealing

State-Space Piece-Wise Affine System Identification with Onl...

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European control Conference (ECC)

作者： Christos N. Mavridis Aris Kanellopoulos John S. Baras Karl Henrik Johansson Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm Department of Electrical and Computer Engineering and the Institute for Systems Research University of Maryland College Park USA

ISBN: (数字)9783907144107

ISBN: (纸本)9798331540920

We propose an online identification scheme for discrete-time piece-wise affine state-space models based on a system of adaptive algorithms running in two timescales. A stochastic approximation algorithm implements an online deterministic annealing scheme at a slow timescale, estimating the partition of the augmented state-input space that defines the switching signal. At the same time, an adaptive identification algorithm, running at a higher timescale, updates the parameters of the local models based on the estimate of the switching signal. Identifiability conditions for the switched system are discussed and convergence results are given based on the theory of two-timescale stochastic approximation. In contrast to standard identification algorithms for piece-wise affine systems, the proposed approach progressively estimates the number of modes needed and is appropriate for online system identification using sequential data acquisition. This progressive nature of the algorithm improves computational efficiency and provides real-time control over the performance-complexity trade-off, desired in practical applications. Experimental results validate the efficacy of the proposed methodology.

关键词： Switched systems Annealing Stochastic processes Switches Approximation algorithms Real-time systems System identification

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A Distributed Automatic Domain-Specific Multi-Word Term Recognition Architecture using Spark Ecosystem

A Distributed Automatic Domain-Specific Multi-Word Term Reco...

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International Symposium on Parallel and Distributed Computing

作者： Ciprian-Octavian Truică Neculai-Ovidiu Istrate Elena-Simona Apostol Computer Science and Engineering Department Faculty of Automatic Control and Computers University Politehnica of Bucharest Bucharest Romania

Automatic Term Recognition is used to extract domain-specific terms that belong to a given domain. In order to be accurate, these corpus and language-dependent methods require large volumes of textual data that need to be processed to extract candidate terms that are afterward scored according to a given metric. To improve text preprocessing and candidate terms extraction and scoring, we propose a distributed Spark-based architecture to automatically extract domain-specific terms. The main contributions are as follows: (1) propose a novel distributed automatic domain-specific multi-word term recognition architecture built on top of the Spark ecosystem; (2) perform an in-depth analysis of our architecture in terms of accuracy and scalability; (3) design an easy-to-integrate Python implementation that enables the use of Big Data processing in fields such as Computational Linguistics and Natural Language Processing. We prove empirically the feasibility of our architecture by performing experiments on two real-world datasets.

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Deep Learning ECG Signal Analysis: Description and Preliminary Results 18th

Deep Learning ECG Signal Analysis: Description and Prelimin...

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Dependable computer Systems and Networks - Proceedings of the Eighteenth International Conference on Dependability of computer Systems DepCoS-RELCOMEX

作者： Surowiec, Mateusz Ciskowski, Piotr Kluwak, Kondrad Jeleń, Lukasz Department of Computer Engineering Wroclaw University of Science and Technology Wybrzeże Wyspiańskiego 27 Wroclaw50-370 Poland Department of Control Systems and Mechatronics Wroclaw University of Science and Technology Wybrzeże Wyspiańskiego 27 Wroclaw50-370 Poland

ISBN: (纸本)9783031377198

Electrocardiography is one of the most commonly performed examinations when a patient experiences symptoms of heart disease. A detailed analysis of the problem shows that it can also be used to detect and recognize emotions and activity. In this paper, we present several architectures for the analysis of electrocardiogram (ECG) data. Such architectures could be used for activity and emotion detection in augmentative and alternative communication (AAC) schemes. The use of deep learning algorithms shows the potential of using popular wearable devices and their usefulness for this analysis. Here, we present the preliminary results of our analysis, which provide promising conclusions on the application of a complete AAC framework. The presented methodology is applicable for the classification of the ECG data and can be further used with wearable devices. The conclusions and results of the study presented allow us to investigate real-time data analysis with a wearable device to predict certain cardiac conditions. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Wearable technology

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Coordinated Trajectories for Non-stop Flying Carriers Holding a Cable-Suspended Load

arXiv

引用

arXiv 2025年

作者： Gabellieri, Chiara Franchi, Antonio Faculty University of Twente Enschede7500 AE Netherlands Department of Computer Control and Management Engineering Sapienza University of Rome Rome00185 Italy

Multirotor UAVs have been typically considered for aerial manipulation, but their scarce endurance prevents long-lasting manipulation tasks. This work demonstrates that the non-stop flights of three or more carriers are compatible with holding a constant pose of a cable-suspended load, thus potentially enabling aerial manipulation with energy-efficient non-stop carriers. It also presents an algorithm for generating the coordinated non-stop trajectories. The proposed method builds upon two pillars: (1) the choice of n special linearly independent directions of internal forces within the 3n − 6-dimensional nullspace of the grasp matrix of the load, chosen as the edges of a Hamiltonian cycle on the graph that connects the cable attachment points on the load. Adjacent pairs of directions are used to generate n forces evolving on distinct 2D affine subspaces, despite the attachment points being generically in 3D;(2) the construction of elliptical trajectories within these subspaces by mapping, through appropriate graph coloring, each edge of the Hamiltonian cycle to a periodic coordinate while ensuring that no adjacent coordinates exhibit simultaneous zero derivatives. Combined with conditions for load statics and attachment point positions, these choices ensure that each of the n force trajectories projects onto the corresponding cable constraint sphere with non-zero tangential velocity, enabling perpetual motion of the carriers while the load is still. The theoretical findings are validated through simulations. © 2025, CC BY.

关键词： Trajectories

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