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International Conference of Modelling and Simulation in Engineering, Economics, and Management, MS 2018

作者： Gil-Doménech, Dolors Berbegal-Mirabent, Jasmina Merigó, José M. Department of Economy and Business Organisation Universitat Internacional de Catalunya C. Immaculada 22 Barcelona08017 Spain Department of Management Control and Information Systems University of Chile Av. Diagonal Paraguay 257 Santiago8330015 Chile School of Information Systems and Modelling Faculty of Engineering and Information Technology University of Technology Sydney 81 Broadway UltimoNSW2007 Australia

ISBN: (纸本)9783030154127

In the recent years, STEM (science, technology, engineering and mathematics) education has received increasing attention, and many calls for a fundamental change in this field have emerged. In this context, the analysis of the evolution and development of this scientific domain results crucial. In order to do so, the present study presents a bibliometric overview of the academic research developed in STEM education over the last years. The work uses the Web of Science database and a wide range of bibliometric indicators including the number of publications and citations, the h-index, and citation thresholds. The article also develops a graphical visualisation of the bibliographic data using the visualisation of similarities (VOS) viewer software. Results indicate that the amount of works addressing this topic has substantially increased in the recent years, although the number of citations has not experienced a similar growth rate. Also, when analysing journals and research areas, it can be deduced that the research on STEM education is diverse. The bibliometric analysis performed provides a rigorous and comprehensive view of research on STEM education that might be useful for those researchers interested in advancing future knowledge in this area. © 2020, Springer Nature Switzerland AG.

关键词： Visualization

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Nonlinearity Measures for Distributed Parameter and Descriptor systems

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IFAC-PapersOnLine 2020年第2期53卷 7545-7550页

作者： Pedro Reyero-Santiago Carlos Ocampo-Martinez Rolf Findeisen Richard D. Braatz Automatic Control Department Universitat Politècnica de Catalunya Institut de Robòtica i Informàtica Industrial (CSIC-UPC) 08028 Barcelona Spain Institute for Automation Engineering (IFAT) Laboratory for Systems Theory and Automatic Control Otto-von-Guericke Universität Magdeburg 39106 Magdeburg Germany Massachusetts Institute of Technology Room E19-551 77 Massachusetts Avenue Cambridge MA 02139 USA

control design and state estimation are usually more straightforward for linear than for nonlinear dynamical systems, which has motivated the development of methods for quantifying the extent of nonlinearity in dynamical systems. Although many well-defined methods have been proposed for systems described by ordinary differential equations, such methods are not as well explored for dynamical systems described by PDEs and descriptor systems that represent most chemical processes. This paper reviews, discusses, and compares methods for the definition and computation of nonlinearity measures. The measures are categorized in terms of open- vs. closed-loop control topologies, theoretical vs. numerically computed, state transformation dependency, input scaling dependency, linearization vs. optimized linear modeling vs. average linear modeling, applicability to unstable dynamical systems, and applicability to the right-hand side of the state equation or to input-output relationships. Then extensions of the nonlinearity measures are discussed for hybrid systems and those described by coupled differential, integral, and algebraic equations, often referred to as descriptor/singular systems.

关键词： nonlinear systems process control nonlinear measures descriptor systems distributed parameter systems

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STGCNFormer: Spatio-Temporal Dual-Stream Graph Convolutional Networks and Transformers for Traffic Forecasting

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IEEE Transactions on Vehicular technology 2025年

作者： Yang, Changzhi Pan, Huihui Wang, Jue Harbin Institute of Technology Research Institute of Intelligent Control and Systems Harbin150001 China Tongji University National Key Laboratory of Autonomous Intelligent Unmanned Systems Shanghai201210 China Ningbo Institute of Intelligent Equipment Technology Company Ltd. Ningbo315200 China University of Science and Technology of China Department of Automation Hefei230027 China

In intelligent transportation systems, traffic prediction constitutes the fundamental component of traffic optimization, aiming to precisely forecast traffic flow. Modeling spatio-temporal interactions is a crucial step in achieving long-term and accurate predictions. Traditional methods are mostly based on single-stream networks, which alternately extract spatio-temporal features through sequential iterations. However, time and space are inherently two different modalities. Employing a single-stream network to address multi-modal tasks is suboptimal. In this paper, we propose Spatio-Temporal Dual-Stream Graph Convolutional Networks and Transformers (STGCNFormer), a dual-stream network for traffic forecasting, decoupling spatio-temporal features in parallel through a temporal stream and a spatial stream. The core of STGCNFormer is a STGCNFormer block, comprising three components. The first component is a GCN block, which restricts the kernel of graph convolution and adopts Chebyshev polynomials of the first kind to approximate the convolutional kernel, capturing spatial interactions and achieving localized convolution. Secondly, we present a Transformer block, designed as a simplified version of vanilla Transformers, which captures temporal interactions and significantly reduces computational complexity. Thirdly, we propose a cross attention mechanism, consisting of a temporal attention mechanism and a spatial attention mechanism, which serves as a bidirectional bridge for sharing information between the dual streams. Experimental results demonstrate that STGCNFormer achieves superior prediction accuracy with reduced computational complexity compared with previous state-of-the-art methods. © 1967-2012 IEEE.

关键词： Air traffic control

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Improved photocatalytic production of hydrogen peroxide over graphitic carbon nitride doped with potassium salts

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Journal of Colloid and Interface Science 2025年 695卷 137675页

作者： Jing, Shengyu Xu, Qingyuan Wang, Haoran Kannan, Palanisamy Liang, Huagen Brouzgou, Angeliki Wang, Ruiyu Tsiakaras, Panagiotis School of Information and Control Engineering China University of Mining and Technology Xuzhou221116 China Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization Carbon Neutrality Institute China University of Mining and Technology Xuzhou221008 China College of Biological Chemical Sciences and Engineering Jiaxing University Jiaxing314001 China Department of Energy Systems Faculty of Technology University of Thessaly Larisa Geopolis41500 Greece Laboratory of Alternative Energy Conversion Systems Department of Mechanical Engineering School of Engineering University of Thessaly Pedion Areos38334 Greece

Hydrogen peroxide (H2O2) has long been recognized as an important green cleaning chemical. Due to its narrow bandgap and nitrogen-rich structure, graphitic carbon nitride (g-C3N5) is considered a promising photocatalyst for H2O2 generation. However, the limited visible light harvesting capacity and weak charge separation ability of bulk g-C3N5 limit its photocatalytic activity. Herein, to address the low photogenerated carrier mobility of g-C3N5, we successfully synthesized a series of K-ion-doped g-C3N5 (KCN) by co-calcination of 3-amino-1,2,4-triazole with potassium salt. The effects of different potassium salts (potassium oxalate-K2C2O4, potassium nitrate-KNO3, and potassium hydroxide-KOH) and different additions on the photocatalytic ability of g-C3N5 were compared and systematically analyzed. The results showed that the KCN sample synthesized with KOH as dopant exhibits the highest H2O2 yield up to 1546.7 µmol L−1h−1, seven times more than that of pure g-C3N5. The excellent photocatalytic H2O2 evolution efficiency is confirmed by DFT calculations to be mainly attributed to the rational design of g-C3N5, which produces more pronounced cyano groups under high-temperature calcination and alkaline environment while promoting the formation of N vacancies. This design effectively promotes the separation of electron-hole pairs and the optimization of carrier transport capacity, and as a result, KOH doping exhibits better photocatalytic performance. The current work provides a more favorable modification strategy for future solar energy conversion. © 2025 Elsevier Inc.

关键词： Potassium hydroxide

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Soft Starters of Powerful Electric Motors and Economic Aspects of Their Application 25

Soft Starters of Powerful Electric Motors and Economic Aspec...

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25th IEEE International Conference on Problems of Automated Electric Drive. Theory and Practice, PAEP 2020

作者： Tytiuk, Valerii Rozhnenko, Zhanna Baranovska, Mila Berdai, Abdelmajid Chornyi, Oleksii Saravas, Viktoriya Kryvyi Rih National University Kryvyi Rih Ukraine University Hassan Ii of Casablanca National School of Electricity and Mechanics Ensem Casablanca Morocco Institute of Electromechanics Energy Saving and Automatic Control Systems Kremenchuk Mykhailo Ostrogradskyi National University Kremenchuk Ukraine Pryazovskyi State Technical University Power Energy Department Mariupol Ukraine

ISBN: (纸本)9781728199351

The paper dedicated to the development of methods for determining economic efficiency in the implementation of starting devices of powerful electric motors. Currently, manufacturers of starting devices provide only general information about the various technical advantages of using soft starters, without affecting the economic aspects of their application. The start-up of powerful electric motors has a profound effect on the reliability of electromechanical equipment and creates additional economic risks for the enterprise. It is for powerful electric motors that the decision to use a soft starter needs a deep economic justification, since such engine operate in a long mode, and the initial cost of a soft starter is high. The results obtained make it possible to evaluate the planned economic effect of the introduction of soft starters for high power electric motors and, thereby, will further expand the market of soft starters in the medium and high power segment. © 2020 IEEE.

关键词： Economic efficiency

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Adaptive voltage regulation of an inverter-based power distribution network with a class of droop controllers ??

arXiv

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arXiv 2020年

作者： Chong, Michelle S. Sandberg, Henrik Department of Mechanical Engineering Eindhoven University of Technology Netherlands Division of Decision and Control Systems KTH Royal Institute of Technology Sweden

The voltage received by each customer connected to a power distribution line with local controllers (inverters) is regulated to be within a desired margin through a class of slope-restricted controllers, known conventionally as droop controllers. We adapt the design of the droop controllers according to the known bounds of the net power consumption of each customer in each observation time window. A sufficient condition for voltage regulation is provided for each time window, which guides the design of the droop controllers, depending on the properties of the distribution line (line impedances) and the upper bound of all the customers’ power consumption during each time window. The resulting adaptive scheme is verified on a benchmark model of a European low-voltage network by the CIGRE task force. Copyright © 2020, The Authors. All rights reserved.

关键词： Sales

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Distributed training and scalability for the particle clustering method UCluster

arXiv

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arXiv 2021年

作者： Gudnadottir, Olga Sunneborn Gedon, Daniel Desmarais, Colin Bernander, Karl Bengtsson Sainudiin, Raazesh Suarez, Rebeca Gonzalez Department of Physics and Astronomy Division of High Energy Physics Uppsala University Department of Information Technology Division of Systems and Control Uppsala University Department of Information Technology Division of Visual Information & Interaction Uppsala University Department of Mathematics Uppsala University Combient Competence Centre for Data Engineering Sciences Uppsala University

In recent years, machine-learning methods have become increasingly important for the experiments at the Large Hadron Collider (LHC). They are utilised in everything from trigger systems to reconstruction and data analysis. The recent UCluster method is a general model providing unsupervised clustering of particle physics data, that can be easily modified to provide solutions for a variety of different decision problems. In the current paper, we improve on the UCluster method by adding the option of training the model in a scalable and distributed fashion, and thereby extending its utility to learn from arbitrarily large data sets. UCluster combines a graph-based neural network called ABCnet with a clustering step, using a combined loss function in the training phase. The original code is publicly available in TensorFlow v1.14 and has previously been trained on a single GPU. It shows a clustering accuracy of 81% when applied to the problem of multi-class classification of simulated jet events. Our implementation adds the distributed training functionality by utilising the Horovod distributed training framework, which necessitated a migration of the code to TensorFlow v2. Together with using parquet files for splitting data up between different compute nodes, the distributed training makes the model scalable to any amount of input data, something that will be essential for use with real LHC data sets. We find that the model is well suited for distributed training, with the training time decreasing in direct relation to the number of GPU’s used. However, further improvements by a more exhaustive and possibly distributed hyper-parameter search is required in order to achieve the reported accuracy of the original UCluster method. Copyright © 2021, The Authors. All rights reserved.

关键词： Learning systems

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Input-to-State Stability of Networked and Quantized control systems ⁎

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IFAC-PapersOnLine 2020年第2期53卷 3079-3084页

作者： Wei Ren Junlin Xiong Division of Decision and Control Systems EECS KTH Royal Institute of Technology SE-10044 Stockholm Sweden Department of Automation University of Science and Technology of China Hefei 230026 China

This paper studies input-to-state stability of networked and quantized control systems with external disturbances. Since the external disturbance is considered, the state may escape from the quantization regions, which thus leads to the introduction of the quantization mechanism with zooming-out and zooming-in stages. We first propose a novel hybrid system to incorporate both the open-loop and closed-loop systems. Based on the developed hybrid model, we establish the boundedness of the state in the zooming-out stage, and the convergence of the state in the zooming-in stage. Furthermore, sufficient conditions are established for input-to-state stability in the case of switching between the zooming-in and zooming-out stages. Finally, a numerical example is presented to illustrate the obtained results.

关键词： Hybrid systems networked control systems quantized control system modelling input-to-state stability average dwell-time

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Performance analysis and optimization of power systems with spatially correlated noise

arXiv

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arXiv 2020年

作者： Jouini, Taouba Sun, Zhiyong Department of Automatic Control LTH Lund University Ole Rmers vg 1 Lund22363 Sweden Department of Electrical Engineering Eindhoven University of Technology Netherlands

Based on stochastic differential equations (SDEs), we analyse the overall performance of heterogeneous power systems network, subject to spatially distributed and correlated noise with random initial conditions. We determine bounds on the H2 norm of the heterogeneous system based on a closed-form of the norm of the homogeneous power system. Then, we formulate possible scenarios for performance optimization and link these to applications for network design and control problems in power systems. Our results are corroborated by numerical simulations from Kundur’s four-machine two-area network after adaption to our setup. Copyright © 2020, The Authors. All rights reserved.

关键词： White noise

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Performance Analysis of OMA/NOMA-aided Satellite Communication Networks: A Stochastic Geometry Approach

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IEEE Transactions on Communications 2024年

作者： Li, Kecheng Wang, Jun Hou, Tianwei Li, Anna Yue, Xinwei Liu, Yuanwei Chen, Wei School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom KU Leuven Leuven3001 Belgium School of Computing and Communications Lancaster University LancasterLA1 4WA United Kingdom Key Laboratory of Information and Communication Systems Ministry of Information Industry China Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science and Technology University Beijing100101 China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong

The increasing quality of service requirements and demand for satellite services necessitate higher data rates, spectral efficiency, and stability in satellite communication networks. Therefore, this paper investigates the non-orthogonal multiple access (NOMA) assisted satellite communication networks, where multiple users are uniformly distributed over a spherical hat according to the homogeneous Poisson point process (HPPP). Based on the characteristics of HPPP, we analyze the distance distributions of users. To evaluate the performance of the proposed networks, we first derive the closed-form expressions and approximated expressions of the outage probability (OP) for paired NOMA users. To obtain more insights into the proposed networks, the ergodic rate and diversity orders for paired NOMA users are also derived. Spectral efficiency is derived for NOMA and orthogonal multiple access (OMA) assisted satellite communication networks. Our analytical results demonstrate that the diversity order of the proposed networks is all one. Numerical results confirm that: 1) compared to OMA, the proposed NOMA-assisted satellite network demonstrates superior outage performance and spectral efficiency, especially in the higher power regimes;2) fading factors have negligible effects on OP and spectral efficiency;and 3) under certain target rates for both near and far users, the outage performance of far users in NOMA-assisted satellite communication networks is superior to that of near users. © 2024 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.

关键词： Satellite communication systems

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