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Colombian Caribbean Conference (C3), IEEE

作者： Eduardo Dias Pedro Ulhoa Rafhael Andrade Department of Mechanical Engineering. Universidade Federal do Espírito Santo Vitória Brazil Department of Electrical Engineering Universidade Federal do Espírito Santo Vitória Brazil Graduate Program in Mechanical Engineering Universidade Federal do Espírito Santo Vitória Brazil

Exoskeletons are wearable mechanisms which, parallel to the wearer’s joints, modulate movements through active or passive torque application. While existing upper-limb exoskeletons offer benefits in strength augmentation and therapy, they often suffer from limited degrees of freedom and excessive bulk, hindering their utility in neuromotor rehabilitation. This study introduces a three degree-of-freedom active upper-limb exoskeleton optimized for neuromotor rehabilitation. Employing anthropometric data and rigorous kinematic analysis, the design accommodates elbow flexion/extension, forearm pronation/supination, and hand gripping. The upper limb dynamics, kinematics, and physiology were evaluated to provide adequate joint ranges of motion. Cable-driven actuators in the elbow and forearm joints were designed to provide low worn weight through the relocation of the motor units away from the user’s joints. The result is a lightweight, compact exoskeleton that provides optimal conditions for neuromotor rehabilitation. Finally, a preliminary control strategy was tested using myoelectric signals to trigger motion.

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Fault Analysis of a Ladle Furnace Transformer caused by Switching Transient and Ferroresonance

Fault Analysis of a Ladle Furnace Transformer caused by Swit...

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International Conference on engineering and Emerging Technologies (ICEET)

作者： Virna C. Onofri Thales A. C. Maia Graduate Program in Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte MG Brazil Department of Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte MG Brazil

ISBN: (纸本)9781665491075

Electric Arc Furnace and Ladle Furnace transformers are very important in steel production industry. The overvoltages caused by vacuum circuit breaker during operation are very repetitive and can lead to failures and, consequently, large financial losses. The use of protection devices, as RC filters and surge arresters, can attenuate theses transient overvoltages. However, the clamping of one of the circuit breaker phases, which is a common event to occur in a system like this, can cause failure to one of the phases of the transformer protection system, due to ferroresonance effect. Operation of this transformer without one of the phases of the RC filter and surge arrest will likely lead it to failure after repetitive overvoltages. This paper presents the study and analysis of the cause of insulation failure in a no-load Ladle Furnace (LF) transformer caused by overvoltages during vacuum circuit breaker switching transients and by ferroresonance effects. The system of a real steel mill is modelled and will be used to perform simulations in Simulink/Matlab.

关键词： Insulation Furnaces Circuit breakers Ferroresonance Steel Surges Integrated circuit modeling

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Age Optimal Sampling for Unreliable Channels Under Unknown Channel Statistics

Age Optimal Sampling for Unreliable Channels Under Unknown C...

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International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)

作者： Hongyi He Haoyue Tang Jiayu Pan Jintao Wang Jian Song Leandros Tassiulas Beijing National Research Center for Information Science and Technology (BNRist) Department of Electronic Engineering Tsinghua University Beijing China Department of Electronic Engineering Yale University New Haven USA Department of Electrical and Computer Engineering The Ohio State University Columbus OH USA Research Institute of Tsinghua University in Shenzhen Shenzhen China Shenzhen International Graduate School Tsinghua University Shenzhen China

In this work, we study a system with a sensor forwarding status update to the receiver through an error-prone channel, and the receiver sends the transmission results to the sensor via a reliable link. We assume both transmission links suffer from random delays. We use Age of Information (AoI) to measure the freshness of the status information at the receiver. Our goal is to design a sampling policy that minimizes the expected time average AoI when the channel statistics are unknown. The problem is reformulated into a renewal-reward process optimization, and an online algorithm based on the Robbins-Monro algorithm is proposed. We prove that when the forward and backward transmission delays are bounded, the AoI difference between the online algorithm and the optimal policy decays with rate $\mathcal{O}(\ln K/K)$ , where $K$ is the number of successful transmissions. Simulation results validate the performance of our proposed algorithm.

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Balanced coding with Lehmer code

Balanced coding with Lehmer code

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International Symposium on Information Theory and Its Applications, ISITA

作者： Hiroshi Kamabe Takumi Marumo Shan Lu Dept. of Electrical Electronic and Computer Engineering Faculty of Engineering Gifu University Gifu Japan Department of Intelligence Science and Engineering Graduate School of Natural Science and Technology Gifu University Gifu Japan

ISBN: (数字)9784885523410

ISBN: (纸本)9781665499071

We propose two balanced coding schemes based on the Lehmer code. The first one is very efficient because it is essentially an enumerative coding without any loss. However, it needs an arithmetic device with very long precision proportional to the output block length. The redundancy of the second coding scheme is almost log n, where n is the length of the output block. The scheme needs a list of numbers with length n and lists of numbers with length n/2 in encoding.

关键词： Codes Redundancy Encoding Arithmetic

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A 35 V-5 V monolithic integrated GaN-based DC-DC floating buck converter

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Semiconductor Science and Technology 2023年第9期38卷 095001-095001页

作者： Zhu, Yuhao Su, Haodong Li, Fan Li, Ang Lei, Xiaohaoyang Cui, Miao Lai, Wen-Cheng Wen, Huiqing Liu, Wen School of Advanced Technology Xi’an Jiaotong-Liverpool University Suzhou China Department of Electrical Engineering and Electronics University of Liverpool Liverpool United Kingdom Bachelor Program in Industrial Projects National Yunlin University of Science and Technology Yunlin Taiwan Department of Electronic Engineering National Yunlin University of Science and Technology Yunlin Taiwan

The paper presents the development of a GaN DC-DC power converter with a pre-driver module and power device based on a monolithic integrated GaN E/D-mode metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) platform. The pre-driver module with direct coupled field effect transistor logic circuit structure has been monolithically integrated with a GaN power transistor on a Si-based AlGaN/GaN commercial epitaxial wafer. The MIS-HEMTs structure adopts an insulated gate dielectric layer to suppress the leakage current and increase gate voltage robustness. The GaN-based floating buck converter employs a 1 mH inductor and a 9 μF capacitor to achieve 35 V-5 V power conversion. As a result, the pre-driver module is capable of delivering a 10 V driving voltage. GaN monolithic integration of the pre-driver module and power device can reduce the system area in the DC-DC application, which allows for an integrated chip size of 1.8 mm2 © 2023 IOP Publishing Ltd

关键词： III-V semiconductors

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Vision-based Semantic Communications for Metaverse Services: A Contest Theoretic Approach

Vision-based Semantic Communications for Metaverse Services:...

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IEEE Conference on Global Communications (GLOBECOM)

作者： Guangyuan Liu Hongyang Du Dusit Niyato Jiawen Kang Zehui Xiong Boon Hee Soong Energy Research Institute@NTU Interdisciplinary Graduate Program School of Computer Science and Engineering Nanyang Technological University Singapore School of Computer Science and Engineering Nanyang Technological University Singapore School of Automation Guangdong University of Technology China Pillar of Information Systems Technology and Design Singapore University of Technology and Design Singapore Department of Electrical and Electronic Engineering Nanyang Technological University Singapore

The popularity of Metaverse as an entertainment, social, and work platform has led to a great need for seamless avatar integration in the virtual world. In Metaverse, avatars must be updated and rendered to reflect users' behaviour. Achieving real-time synchronization between the virtual bilocation and the user is complex, placing high demands on the Metaverse Service Provider (MSP)'s rendering resource allocation scheme. To tackle this issue, we propose a semantic communication framework that leverages contest theory to model the interactions between users and MSPs and determine optimal resource allocation for each user. To reduce the consumption of network resources in wireless transmission, we use the semantic communication technique to reduce the amount of data to be transmitted. Under our simulation settings, the encoded semantic data only contains 51 bytes of skeleton coordinates instead of the image size of 8.243 megabytes. Moreover, we implement Deep Q-Network to optimize reward settings for maximum performance and efficient resource allocation. With the optimal reward setting, users are incentivized to select their respective suitable uploading frequency, reducing down-sampling loss due to rendering resource constraints by 66.076% compared with the traditional average distribution method. The framework provides a novel solution to resource allocation for avatar association in VR environments, ensuring a smooth and immersive experience for all users.

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A Large Reservoir Computing Forecasting Method Based on Randomized Fuzzy Cognitive Maps

A Large Reservoir Computing Forecasting Method Based on Rand...

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IEEE Workshop on Evolving and Adaptive Intelligent Systems (EAIS)

作者： Omid Orang Fabricio J. Erazo-Costa Petrônio C. L. Silva Guilherme de Alencar Barreto Frederico Gadelha Guimarães Department of Computer Science Universidade Federal de Minas Gerais Belo Horizonte Brazil Graduate Program in Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte Brazil Federal Institute of Northern Minas Gerais Januária Campus Brazil Department of Teleinformatics Engineering Universidade Federal do Ceará Fortaleza Brazil

ISBN: (数字)9798350366235

ISBN: (纸本)9798350366242

This paper introduces a novel forecastings technique based on randomized fuzzy cognitive maps (FCM), called LRHFCM (or large reservoir of randomized high-order FCM) for predicting univariate time series. LR-HFCM is a hybrid method combining fuzzy time series (FTS), FCMs, and reservoir computing. It is a type of echo state network (ESN) consisting of the input layer, intermediate (or large reservoir) layer, and output layer, where LASSO regression is applied to train the output layer. The novelty of this approach is that the internal layer includes a very large reservoir, considering different combinations from the sets of concepts and order using a certain number of sub-reservoirs to capture different dynamics of input time series. It is important to highlight that the weights within each sub-reservoir are chosen randomly and remain constant throughout the training process. The validity of the LR-HFCM approach is evaluated across 15 different time series datasets. The results highlight the outperformance of the LR-HFCM technique in comparison to various baseline models.

关键词： Training Adaptation models Adaptive systems Computational modeling Time series analysis Fuzzy cognitive maps Reservoirs

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Design of Mission Profile Emulator for Battery Degradation Tests

Design of Mission Profile Emulator for Battery Degradation T...

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IEEE Annual Southern Power electronics Conference (SPEC)

作者： Pedro Ivo De Oliveira Tironi Heverton Augusto Pereira Victor Flores Mendes Allan Fagner Cupertino Graduate Program in Electrical Engineering Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG) Belo Horizonte Brazil Department of Electrical Engineering Universidade Federal de Virçosa (UFV) Viçosa Brazil Department of Electrical Engineering Universidade Federal de Minas Gerais (UFMG) Belo Horizonte Brazil Department of Electrical Energy Universidade Federal de Juiź de Fora (UFJF) Juiz de Fora Brazil

This research paper introduces a perspective for the design of a power converter to test batteries and evaluate their performance under realistic operational conditions based on sinusoidal ripple current. A design of a mission profile emulator (MPE) is proposed to generate battery test scenarios by implementing signals from real-world applications, such as a Modular Multilevel Converter (MMC) or a single-phase inverter. The proposed MPE is based on a synchronous buck converter in conventional and interleaved versions. The proposal is validated through PLECS simulations and Hardware-in-the-Ioop (HIL) experiments. The research investigates the relationship between control bandwidth and harmonic tracking capability for emulation purposes. This analysis centers on optimizing the converter design and enhancing comprehension of the battery's behavior, particularly when the current exhibits sinusoidal components. HIL experiments explore four distinct scenarios, illustrating behavior in simple buck converter systems and demonstrating bandwidth extension and ripple reduction in interleaved systems. The study validates these findings by examining Total Harmonic Distortion (THD) and current ripple across various conditions.

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Miniaturized Quad-Band Filter Design Using Substrate Integrated Coaxial Cavity

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Micromachines 2023年第2期14卷 347-347页

作者： Hsu, Chung-I G. Hong, Wanchu Chen, Mingchih Tu, Wei-Chun Su, Gwan-Wei Ho, Min-Hua Department of Electrical Engineering College of Engineering National Yunlin University of Science and Technology Yunlin64002 Taiwan Department of Electronic Engineering College of Engineering National Changhua University of Education Chunghua50007 Taiwan Graduate Institute of Business Administration College of Management Fu Jen Catholic University New Taipei City24205 Taiwan Universal Microwave Technology Inc Keelung20647 Taiwan Wistron Corporation Taipei11469 Taiwan

We propose a miniaturized quad-band filter (QBF), designed using substrate-integrated coaxial cavities (SICCs). The employed SICC structure consists of two vertically stacked substrates with a large circular patch embedded in between. The embedded patch is segmented unevenly into four pieces, which are shorted to the cavity’s bottom wall through one or two blind vias. This SICC structure exhibits four independently controlled resonances with frequencies much lower than the frequency of its conventional SIW cavity counterpart, thus achieving size reduction. A sample quad-band filter is designed and fabricated for experimental measurement. Reasonably good agreement between measured and simulated data is observed. © 2023 by the authors.

关键词： Substrates

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Evaluating a New Configuration for Medium-Voltage Drive Systems in a Mining Plant

Evaluating a New Configuration for Medium-Voltage Drive Syst...

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Industrial Applications Society Annual Conference on Petroleum and Chemical Industry

作者： André M. Alzamora Caio Eduardo Silva Marco T. A. Êvo Hélder De Paula Graduate Program in Electrical Engineering Federal University of Uberlândia (UFU) Uberlândia MG Brazil Electrical Engineering Department (DEPEL) Federal University of São João del-Rei (UFSJ) São João del-Rei MG Brazil Faculty of Electrical Engineering (FEELT) Federal University of Uberlândia (UFU) Uberlândia MG Brazil

Large AC motors are ubiquitous in the mining industry, and these often require medium-voltage (MV) converters. Generally, long cables provide the connection between the variable speed drive (VSD) and the motor, which increases problems involving high frequency currents and overvoltages. These undesired phenomena are attenuated by large, heavy and expensive inverter output filters. As an alternative solution to such problems, the authors have proposed, in previous works, the separation of the frequency converter into its rectifier and inverter units, where the rectifier remains in its original location and the inverter is placed beside the motor, thus establishing a DC transmission link through the long cable. Such a configuration naturally (i) mitigates the high-frequency phenomena, (ii) reduces the voltage drop along the cable, and (Hi) can result in substantial copper savings. Until the present moment, the evaluations performed on the proposed topology was aimed at low voltage mining applications, which have shown excellent results. However, since MV drive systems are common in the mining industry, the proposed drive topology should also be analyzed considering this application. In this way, this paper evaluates the copper and energy savings obtained through this alternative drive topology by means of a case study involving three MV motor drive systems situated in a mining plant.

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