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arXiv 2024年

作者： Zhao, Changyuan Du, Hongyang Liu, Guangyuan Niyato, Dusit College of Computing and Data Science Nanyang Technological University Singapore CNRS@CREATE 1 Create Way # 08-01 Create Tower 138602 Singapore Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong The Energy Research Institute @ NTU Interdisciplinary Graduate Program Singapore

Score-based generative models can effectively learn the distribution of data by estimating the gradient of the distribution. Due to the multi-step denoising characteristic, researchers have recently considered combining score-based generative models with the gradient boosting algorithm, a multi-step supervised learning algorithm, to solve supervised learning tasks. However, existing generative model algorithms are often limited by the stochastic nature of the models and the long inference time, impacting prediction performances. Therefore, we propose a Supervised Score-based Model (SSM), which can be viewed as a gradient boosting algorithm combining score matching. We provide a theoretical analysis of learning and sampling for SSM to balance inference time and prediction accuracy. Via the ablation experiment in selected examples, we demonstrate the outstanding performances of the proposed techniques. Additionally, we compare our model with other probabilistic models, including Natural Gradient Boosting (NGboost), Classification and Regression Diffusion Models (CARD), Diffusion Boosted Trees (DBT), and non-probabilistic GBM models. The experimental results show that our model outperforms existing models in both accuracy and inference time. © 2024, CC BY.

关键词： Self-supervised learning

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A Fiber Bragg Grating based Accelerometer for Monitoring the Vibration of an Industrial Engine Prototype: A Preliminary Study 5

A Fiber Bragg Grating based Accelerometer for Monitoring the...

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5th International Conference on Applications of Optics and Photonics, AOP 2022

作者： Silveira, Mariana Avellar, Leticia Cruzeiro, Filipe Macedo, Leandro Leal-Junior, Arnaldo Garcia, Guilherme Frizera, Anselmo Díaz, Camilo Telecommunications Laboratory LABTEL Electrical Engineering Department Federal University of Espírito Santo Espírito Santo29075-910 Brazil Graduate Program in Mechanical Engineering Federal University of Espírito Santo Fernando Ferrari Avenue-ES Vitória29075-910 Brazil ArcelorMittal Global R&D Brazil

Monitoring the vibration of industrial engines is essential for running diagnostics that can detect faults and point out the feasibility of predictive maintenance. Therefore, this paper describes an optical accelerometer based on a fiber Bragg grating to monitor the vibration of the gearbox of an industrial engine prototype. Experimental tests were performed varying the motor's rotation speed during normal operation. To validate the proposed system, two electronic accelerometers were attached to the motor's gearbox and bearing. The natural frequency response of the optical accelerometer was simulated and good agreement with the experimental results was obtained (0.83% of error). The proposed sensor was able to correctly identify the operation speeds of 20, 25, 35, 40, 45 and 50 rps with a maximum error of 0.05%. The mean signal-to-noise ratio (SNR) of the optical accelerometer was 64.05% higher than the SNR of one of the electronic solutions. The experimental results show that the vibration signals have different characteristics when measured at the bearings and at the gearbox, indicating the feasibility of multi-signals analysis for fault detection. © Published under licence by IOP Publishing Ltd.

关键词： Accelerometers

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A Method for Automatic Generation of 3D Background Models Using Fractal Models and Genetic Algorithms

A Method for Automatic Generation of 3D Background Models Us...

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International Symposium on Computing and Networking Workshops (CANDARW)

作者： Kaito Watanabe Hirotaka Nakayama Atsushi Shiraki Tomoyoshi Ito Katsumi Hirata Naoto Hoshikawa Advanced Course General Engineering Program National Institute of Technology Oyama College Oyama Japan Center for Computational Astrophysics National Astronomical Observatory of Japan Mitaka Japan Graduate School of Engineering Chiba University Chiba Japan Department of Innovative Electrical and Electronic Engineering National Institute of Technology Oyama College Oyama Japan Graduate School of Science and Tecnology University of Tsukuba Tsukuba Japan

In recent years, 3DCG-related industries have grown rapidly and the demand for 3DCG content has increased. However, 3DCG production requires special skills and a lot of time. In particular, the creation of background data requires a lot of human resources at the production site because the data is huge and complex. Therefore, we propose an automatic creation system that generates 3D background data for 3DCG production. The proposed system consists of three functions: 3D model generation, generation parameter optimization, and fitness evaluation. The user inputs a landscape photograph as idea information into the system, and the system optimizes the generation parameters so that the 3D object shape approximates the input image. To evaluate the accuracy of the system's performance, we observe the optimization process and the 3D object output when a previously generated fractal image or landscape photos are input. Experimental results show that the system accurately optimizes the generation parameters and generates 3D objects that are almost identical to the shape of the fractal image. In addition, the parameters were also optimized with a certain degree of accuracy for landscape photographs for which no specific solution had been determined.

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On dc-Link Capacitor Reliability in Photovoltaic Inverters with Harmonic Current Compensation 8

On dc-Link Capacitor Reliability in Photovoltaic Inverters w...

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8th Southern Power electronics Conference and the 17th Brazilian Power electronics Conference, SPEC / COBEP 2023

作者： De Barros, Rodrigo Cassio De Sousa, Renata Oliveira Amorim, William Caires Silva Cupertino, Allan Fagner Pereira, Heverton Augusto Universidade Federal Do Recôncavo da Bahia Centro de Ciências Exatas e Tecnológicas Bahia Cruz das Almas Brazil Universidade Tecnológica Federal Do Paraná Department of Electronics Paraná Brazil Universidade Federal de Minas Gerais Graduate Program in Electrical Eng. Minas Gerais Brazil Universidade Federal de Juiz de Fora Department of Electrical Energy Juiz de Fora Brazil Universidade Federal de Viçosa Department of Electrical Engineering Viçosa Brazil

ISBN: (纸本)9798350321128

Photovoltaic (PV) inverters can provide ancillary services to the electrical grid, such as harmonic current compensation (HCC), reactive power injection, power smoothing and frequency regulation. Even though this extra functionality can improve the grid power quality, the reliability of the power electronics components of the PV inverter can be affected. Some studies performed further analysis in the semiconductor devices operating as HCC. However, there is a lack in the literature exploring the HCC effect in the dc-link capacitors. Thus, the main objective of this work is perform a further analysis in the HCC operation effects on the dc-link capacitor. The influences of the harmonic order, amplitude and phase angles on the dc-link capacitor are explored. In addition, thermal experimental results of the dc-link capacitor temperatures are performed to evidence the simulation results. Based on the results obtained in this work, the HCC affects the dc-link capacitor power losses and lifetime consumption. The harmonic order directly affects the dc-link power losses and it is higher when the 5th and 7th harmonic orders are compensated simultaneously. In addition, the compensation of 7th harmonic order presents higher power losses than the 5th harmonic component. It was also observed that harmonic phase-angle does not present significant effect in the dc-link capacitor power losses. © 2023 IEEE.

关键词： dc-link capacitor Harmonic Current Compensation lifetime evaluation power losses

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Hybrid Machine Learning Approach for Enhanced Vulnerability Detection in Cloud Environments Using NIST and MITRE Frameworks

Hybrid Machine Learning Approach for Enhanced Vulnerability ...

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Advanced Research in Computing (ICARC), International Conference on

作者： N W Chanaka Lasantha M W P Maduranga Ruvan Abeysekara Valmik Tilwari Nilotpal Chakraborty Debashree Sharma Faculty of Graduate Studies IIC University of Technology Phnom Penh Cambodia Department of Electrical and Electronic Engineering University of Sri Jayewardenepura Nugegoda Sri Lanka Faculty of Computing BCAS Campus Colombo Sri Lanka Department. of Electronics & Communication Engineering Indian Institute of Information Technology Guwahati India Department of Computer Science Engineering Indian Institute of Information Technology Guwahati India Department of Electronics & Communication Engineering Indian Institute of Information Technology Guwahati India

ISBN: (数字)9798331530983

ISBN: (纸本)9798331530990

Cloud security is challenged by constant adaptive cyber threats and traditional detection methods lack real time adaptability. In this paper, we propose a new hybrid ML approach stitching data from National Institute of Standards and Technology (NIST) and MITRE Adversarial Tactics, Techniques and Common Knowledge (ATT&CK) databases together. In contrast to existing methods, this framework combines, in unique and unprecedented fashion, ensemble ML models and Realtime data processing for increased detection accuracy and reduced false positives. This approach addresses specific challenges in the cloud environments and by leveraging standardised frameworks, it offers actionable audiences for efficient and effective vulnerability management process. The framework is validated by the experimental results which prove its robustness to evolution of the cybersecurity demands.

关键词： Adaptation models Accuracy Cloud computing security Scalability NIST Transformers Data models Threat assessment Robustness Anomaly detection

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Assessment of force control improvement induced by sinusoidal vibrotactile stimulation in dominant and non-dominant hands

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Research on Biomedical engineering 2021年第1期37卷 95-103页

作者： Germer, Carina Marconi Moreira, Luciana Sobral Elias, Leonardo Abdala Department of Electronics and Biomedical Engineering School of Electrical and Computer Engineering University of Campinas CampinasSP Brazil Neural Engineering Research Laboratory Center for Biomedical Engineering University of Campinas CampinasSP Brazil Cellular and Structural Biology Graduate Program Institute of Biology University of Campinas CampinasSP Brazil Faculty of Biological Sciences Center for Life Sciences Pontifical Catholic University of Campinas CampinasSP Brazil

Purpose: Vibrotactile stimulation has been shown to improve sensorimotor integration in the central nervous system, thereby enhancing motor performance in several conditions. Here we aim to address two questions: (1) Would lateral asymmetries yielding handedness influence the force control improvement induced by sinusoidal vibrotactile stimulation? (2) Does the force control improvement depend on finding an optimum stimulus intensity? Methods: Eleven participants performed a visually guided force-matching task, while different intensities of sinusoidal vibrations were applied to the index finger skin. Tasks consisted of abductions of the index fingers of dominant and non-dominant hands at 5% of their maximal voluntary contractions. The force coefficient of variation (CoV) in the condition without vibration was used as the reference (control) for later comparison with five vibration intensities. Also, force CoV in the control condition was compared with those obtained from the optimal vibration selected either from both hands or from a single hand (the one that started the experiment). Results: Despite the known sensory asymmetries in cortical and spinal circuits, handedness did not significantly influence the improvement of force control induced by sinusoidal vibrotactile stimulation during low-intensity contractions. Moreover, there was a significant reduction in force variability irrespective of the criteria used to select the vibration intensity. Conclusion: These findings add to the current knowledge on the effects of sinusoidal vibrotactile stimulation on force control and have potential implications for the development of wearable motor enhancer devices. © 2020, Sociedade Brasileira de Engenharia Biomedica.

关键词： Force control

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Impact on mental health due to COVID-19 pandemic: A cross-sectional study in Bangladesh

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Clinical eHealth 2023年第1期6卷 42-52页

作者： Pathan, Refat Khan Biswas, Munmun Yasmin, Suraiya Uddin, Mohammad Amaz Das, Anindya Khandaker, Mayeen Uddin Faruque, M.R.I. Sarker, Moniruzzaman Dept. of Computing and Information Systems School of Engineering and Technology Sunway University Selangor Bandar Sunway 47500 Malaysia Dept. of Computer Science and Engineering BGC Trust University Bangladesh Chittagong 4381 Bangladesh Department of Computer and Information Science Tokyo University of Agriculture and Technology Koganei - 184-0012 Tokyo Japan Dept. of Computer Science and Engineering Chittagong University of Engineering and Technology Chittagong 4349 Bangladesh Dept. of Electrical and Electronic Engineering Chittagong University of Engineering and Technology Chittagong 4349 Bangladesh Center for Applied Physics and Radiation Technologies School of Engineering and Technology Sunway University Selangor Bandar Sunway 47500 Malaysia Space Science Centre Universiti Kebangsaan Malaysia 43600 UKM Selangor Bangi Malaysia Department of Marketing Sunway University Business School Sunway University Selangor Bandar Sunway 47500 Malaysia Faculty of Graduate Studies Daffodil International University Daffodil Smart City Birulia Savar Dhaka – 1216 Bangladesh

The government of Bangladesh has implemented the “Stay Home” policy following the WHO recommendation to resist the community transmission of Covid-19. As a result, the routine activities of all government, semi-government establishments, including educational institutions, are severely affected, and the country's economic growth becomes slowed down. To overcome such a situation, the relevant authorities have introduced the “Work from Home” policy for the employees and “Remote Education” for students. However, due to the persistence of multi-dimensional socio-economic problems, many employees and students face big challenges in performing their regular jobs while adopting such a policy. Consequently, enormous psychological anxiety has been developed for all people, including students, parents, employees, etc., and concurrently created severe changes in their behavior. This study aims to analyze the reasons for the behavioral changes of the employees, students, academic staff, and family members of different ages due to psychological anxiety, stress, or physical issues. A comprehensive online-based survey has been carried out on people working in various sectors in Bangladesh. A modified Apriori Algorithm has been used to sort out the associations between the causes and types of behavioral changes. Analyzed data revealed a massive human behavioral change in most participants. This finding indicates that the negligence of those significant human behavioral changes may cause a higher risk of creating psychological imbalance. Therefore, there is a need to have a solid understanding of the reasons for the behavioral changes and set up standard guidelines to maintain “Work from Home” in this Covid-19 situation to avoid psychological imbalance. Based on this study, some suggestions have been given for implementation by the government on an urgent basis. © 2023

关键词： Apriori algorithm Behavioral changes Covid-19 outbreak Family crisis Work from home

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A Design Approach of Wilkinson Power Divider with Ultra-wideband Bandpass Performance

A Design Approach of Wilkinson Power Divider with Ultra-wide...

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2021 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, iWEM 2021

作者： Wang, Xiaolong Xie, Taiyang Bao, Chunxi Ma, Zhewang Chen, Chun-Ping Lu, Geyu College of Electronic Science and Engineering Jilin University Changchun130012 China Graduate School of Science and Engineering Saitama University Saitama338-8570 Japan Department of Electrical Electronics and Information Engineering Kanagawa University Yokohama221-8686 Japan

ISBN: (纸本)9781665418287

A novel design approach of Wilkinson power divider (WPD) with ultra-wideband (UWB) bandpass performance is reported in this letter. In even-mode analysis, a 100 ? - 50 ? UWB bandpass transformer is summarized and discussed, where the Chebyshev responses of S11, S21 and S31 can be realized by suitable selecting all the characteristic impedances of short-circuited stubs and transmission lines. In odd-mode analysis, several isolation resistors are bridged between upper and lower equivalent circuits, by controlling all the resistances, the isolation performance (S32) and reflection performance (S22 and S33) can be easily suppressed around quite low level. Furthermore, coupled line sections are also considered for miniaturization with proposed optimization algorithm. Finally, two UWB bandpass WPDs are fabricated and measured for verification. © 2021 IEEE.

关键词： Equivalent circuits

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Blocking phenomenon of hard/soft bilayer FePt grains in granular film

Blocking phenomenon of hard/soft bilayer FePt grains in gran...

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Magnetic Conference - Short Papers (INTERMAG Short Papers), IEEE International

作者： Daiki Isurugi Takashi Saito Kim Kong Tham Tomoyuki Ogawa Yoichiro Tanaka Simon John Greaves Shin Saito Department of Electronic Engineering Graduate School of Engineering Tohoku University Sendai Japan Tanaka Kikinzoku Kogyo K. K. Tsukuba Japan Research Institute of Electrical Communication Tohoku University Sendai Miyagi Japan

The structural inhomogeneity of an L1 0 –FePt grain in a granular film was investigated, and its blocking phenomenon was simulated. It was confirmed that 1) structural analysis reveals that both lattice distorted disordered portion at near the interface with MgO underlayer and ordered potion at the upper region exist inside one FePt grain in a granular film, 2) simulation of blocking phenomenon for FePt grains with structural inhomogeneity, hard (order)/soft (disorder) bilayer grains, shows that switching field (H sw ) increases steeply near T C of the disorder layer with decreasing temperature. To generalize blocking phenomenon of the hard/soft bilayer structure, it was found that matching the Curie temperatures of the hard and soft layers leads to high H sw near the T C , which means high robustness against thermal field in random direction. These are useful findings for the design of cap-layer media for HAMR to realize the high spatial resolution.

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Imprinting Spatial Helicity Structure of Vector Vortex Beam on Spin Texture in Semiconductors

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Physical Review Letters 2023年第12期130卷 126701-126701页

作者： Jun Ishihara Takachika Mori Takuya Suzuki Sota Sato Ken Morita Makoto Kohda Yuzo Ohno Kensuke Miyajima Department of Applied Physics Tokyo University of Science Tokyo 125-8585 Japan Graduate School of Electrical and Electronic Engineering Chiba University Chiba 263-8522 Japan Department of Materials Science Tohoku University Sendai 980-8579 Japan Graduate School of Pure and Applied Sciences University of Tsukuba Tsukuba 305-8573 Japan

We present the transfer of the spatially variant polarization of topologically structured light to the spatial spin texture in a semiconductor quantum well. The electron spin texture, which is a circular pattern with repeating spin-up and spin-down states whose repetition rate is determined by the topological charge, is directly excited by a vector vortex beam with a spatial helicity structure. The generated spin texture efficiently evolves into a helical spin wave pattern owing to the spin-orbit effective magnetic fields in the persistent spin helix state by controlling the spatial wave number of the excited spin mode. By tuning the repetition length and azimuthal angle, we simultaneously generate helical spin waves with opposite phases by a single beam.

关键词： Optical spin injection Spin dynamics Spin texture Spin-orbit coupling III-V semiconductors Two-dimensional electron system Magneto-optical Kerr effect Time-resolved reflection spectroscopy

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