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IEEE Conference on Computer Communications Workshops, INFOCOM Wksps

作者： Jingheng Zheng Wanli Ni Hui Tian Deniz Gü ndü z Tony Q. S. Quek State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China Department of Electrical and Electronic Engineering Imperial College London UK Information System Technology and Design Pillar Singapore University of Technology and Design Singapore

In cellular-based federated learning (FL), the base station (BS) is only used to aggregate parameters, which incurs a waste of computing resources at the BS. In this paper, a novel semi-federated learning (SemiFL) framework is proposed to break this bottleneck, where local devices simultaneously send their gradient updates and training samples to the BS for global model computation. To capture the performance of SemiFL over wireless networks, a closed-form convergence upper bound of SemiFL is derived. Then, a non-convex problem is formulated to improve the convergence behavior of SemiFL, subject to the transmit power, communication latency, and computation distortion. To solve this intractable problem, a two-stage algorithm is proposed by controlling the transmit power and receive beamformers. Numerical experiments validate that the proposed SemiFL framework can effectively improve accuracy and accelerate convergence as compared to conventional FL.

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Filter algorithm based on cochlear mechanics and neuron filter mechanism and application on enhancement of audio signals

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Journal of Central South University 2021年第6期28卷 1813-1828页

作者： GAO Wa KAN Yue ZHA Fu-sheng College of Furnishings and Industrial Design Nanjing Forestry UniversityNanjing 210037China School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454003China The State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

A filter algorithm based on cochlear mechanics and neuron filter mechanism is proposed from the view point of *** helps to solve the problem that the non-linear amplification is rarely considered in studying the auditory filters.A cochlear mechanical transduction model is built to illustrate the audio signals processing procedure in cochlea,and then the neuron filter mechanism is modeled to indirectly obtain the outputs with the cochlear properties of frequency tuning and non-linear *** mathematic description of the proposed algorithm is derived by the two *** parameter space,the parameter selection rules and the error correction of the proposed algorithm are *** unit impulse responses in the time domain and the frequency domain are simulated and compared to probe into the characteristics of the proposed *** a 24-channel filter bank is built based on the proposed algorithm and applied to the enhancements of the audio *** experiments and comparisons verify that,the proposed algorithm can effectively divide the audio signals into different frequencies,significantly enhance the high frequency parts,and provide positive impacts on the performance of speech enhancement in different noise environments,especially for the babble noise and the volvo noise.

关键词： cochlea neuron filter audio signal processing speech enhancement

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Link Budget Calculation for LoRa-band Remoting Sensing Satellite

Link Budget Calculation for LoRa-band Remoting Sensing Satel...

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IEEE International Symposium on Electromagnetic Compatibility (EMC-Beijing)

作者： Shurui Wang Xiang Zhang Xiaojun Hao Shuaige Gong Chong Li Qian Xu Lei Xing College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing China College of Mechanical Engineering (Aircraft design and engineering) Nanjing University of Science and Technology Nanjing China State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System (CEMEE) Luoyang China

Small satellites are increasingly attracting the attention of the industry for its many aspects of advantages. We proposed a communication subsystem for commercial remote sensing satellite. The interface between the communication system and other modules on the satellite and the communication protocol are briefly introduced. In order to make sure that the satellite-to-ground link is reliable, we calculate the link budget at 471 MHz for LEO small satellite. Additionally, the transmission power and reception sensitivity is 17 dBm and −123 dBm respectively. The result shows that the proposed subsystem is reliable in RF performance and can be used in other commercial satellite in the future.

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Curvature-property coupling governed heat transfer deterioration in supercritical helically coiled tubes: Mechanistic insights and mitigation strategies via structural parametrization

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International Journal of Thermal Sciences 2025年 215卷

作者： Chang, Fucheng Xin, Jiaxing Wu, Xiaoyi Li, Liwei Li, Huixiong Zhu, Yanlin National Key Lab of Aerospace Power System and Plasma Technology School of Mechanical Engineering Xi'an Jiaotong University Xi'an710049 China China Special Equipment Testing and Research Institute Beijing100029 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China Shanghai Nuclear Engineering Research & Design Institute Co. Ltd Shanghai200233 China

The unique thermo-hydrodynamic coupling phenomena in the helically coiled tube (HCT) handling supercritical fluids present both opportunities and challenges for next-generation compact heat exchangers. While the pronounced thermophysical property variations near pseudo-critical temperatures (Tpc) and curvature-induced secondary flows synergistically enhance heat transfer coefficient (HTC), their nonlinear coupling mechanisms may unexpectedly provoke severe heat transfer deterioration (HTD). Through systematic numerical investigations, this study reveals that circumferential wall temperature inhomogeneity (CWTI) exhibits an inverted N-shaped evolution, providing valuable insights for thermal homogenization design near Tpc. The secondary flow Reynolds number (Se), quantifying secondary flow intensity, shows a monotonic increase with decreasing coil diameter (Dc) or inner diameter (Di), reaching saturation in high-enthalpy regions. Notably, CWTI demonstrates non-monotonic behavior, achieving minimum values near Tpc before manifesting distinct rebound characteristics near Tpc conditions. Parametric analysis establishes that: (1) Elevating heat flux (q) increases Se, reducing Dc boosts it by 50.3 %, and decreasing Di raises it by 60.0 %. (2) HTD predominantly initiates at the outer wall under high-q conditions, with Dc reduction achieving HTD suppression and 26.9 % enhancement in the local HTC;(3) Reducing the Di results in a reduction of maximum CWTI by 22.5 %–28.6 %, suggesting that structural parametrization effectively mitigates wall temperature non-uniformity, thus suppressing the HTD. While centered on supercritical water, the dimensionless scaling relationships demonstrate extendibility to other media, with the curvature-property coupling mechanism both elucidating fundamental interactions and guiding robust heat exchanger design. © 2025 Elsevier Masson SAS

关键词： Electric heating

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Thermal-mechanical coupling behavior analysis of solid-state constrained component in advanced nuclear energy system

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Energy 2025年 330卷

作者： Yang, Xuan Li, Quan Zhang, Jing Wu, Yingwei He, Yanan Li, Chenxi Wang, Mingjun Guo, Kailun Wang, Chenglong Su, G.H. Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

With the advantage of phase change heat transfer, heat pipes have the potential to replace flowing coolants for removing fission heat from nuclear reactors. However, the solid-state constrained heat transfer configuration poses mutual constraints between mechanical properties and heat transfer, and their long-term thermal-mechanical coupling behavior requires further investigation. Currently, research on long-term behavior is limited to either individual/local system components or a single physical field. In this paper, an analysis method for coupled thermal-mechanical behavior is proposed and verified, comprehensively considering thermal-mechanical properties, interactions between components, and the fission gas release. This method is employed to analyze the operating characteristics of a solid-state constrained component. The results indicate that prolonged operation leads to complete contact between structural components, generating high contact pressure that enhances heat transfer but increases creep. The release of gaseous fission products, accumulated over operating time, results in a synchronous increase in both gap and external contact pressures, reaching 5.2 MPa and 4.8 MPa, respectively. This process reduces the gas gap conductance, leading to elevated system peak temperatures and a reduction in temperature safety margins by 43 K. After heat pipe failure, continued operation significantly increases the local creep strain, up to 3.9 times that under normal conditions. The gap size and fuel gap pressure should be optimized to enhance gap heat transfer and reduce component creep. Excessive fission gas release should be avoided in fuel configuration. Reducing the system power following a single heat pipe failure can mitigate component creep and extend the operational lifespan. © 2025 Elsevier Ltd

关键词： Electric heating

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Learnable Operational design Condition Monitor for Failure Prediction in Autonomous Driving

SSRN

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SSRN 2025年

作者： Xu, Haowei Bian, Yougang Li, Yang Qin, Hongmao Zhou, Hanchu Chang, Fangrong Wang, Shaofei Ye, Qing State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Research and Development Center of Transport Industry of Self-driving Technology China Merchants Chongqing Communications Technology Research and Design Institute Co. Ltd. Chongqing China School of Traffic and Transportation Engineering Central South University Changsha China Department of Data and System Engineering The University of Hong Kong Hong Kong School of Resources and Safety Engineering Central South University Changsha China School of Data Science China

Ensuring the safety of Autonomous Driving systems (ADS) across diverse and unpredictable operational scenarios remains a significant challenge for accident prevention. Central to this effort is the continuous monitoring of Operational design Conditions (ODC), which encompass both in-vehicle factors and external Operational design Domain (ODD). However, the absence of robust methodologies to precisely identify ODC boundaries hinders the deployment and adoption of high-level ADS. This paper introduces a learnable ODC monitor designed to identify implicit operational design condition boundaries to prevent ADS failures. By integrating a state-space duality encoder and a Bayesian neural network decoder, we propose an efficient learnable ODC monitor, termed ODCNet. Furthermore, to further enhance prediction reliability, residual error analysis with linear discrimination is applied for calibrating prediction. Experimental results demonstrate ODCNet's superiority in failure prediction compared to baseline models, achieving a balance between safety and coverage. These findings contribute to advancing data-driven accident prediction and prevention strategies, ensuring safer deployments of ADS in complex environments. © 2025, The Authors. All rights reserved.

关键词： Autonomous vehicles

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Study on Evolution Characteristics of Partial Discharge in Transformer Insulating Oil

Study on Evolution Characteristics of Partial Discharge in T...

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International Conference on Power system technology (POWERCON)

作者： Luyao Liu Ziyue Zhang Hongli Zhang Pengfei Lu Haoxi Cong Hongshun Liu Shandong Provincial Key Laboratory of UHV Transmission Technology and Equipment Shandong University Jinan China Qingdao Power Supply Company State Grid Shandong Electric Power Company Qingdao China Mechanical and Electrical Business Department of Tongyuan Design Group Co. Ltd Jinan China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China

As the core equipment of AC power grids, the oil-paper insulation structure of power transformers is prone to accidents such as explosions and fires due to frequent partial discharges. In order to suppress the development of transformers to severe arc discharges and explore the dynamic evolution characteristics of partial discharges from the source, this paper builds an experimental platform for partial discharge image acquisition in oil from the perspective of morphological analysis. Based on a multi-scale retinal algorithm with grey-scale analysis, an enhancement processing algorithm for low-illumination discharge images was designed to extract a continuous discharge profile. The effect of the external applied voltage on the horizontal displacement and half-perimeter distortion of the discharge was then explored. The results show that the horizontal displacement of the discharge at low voltage levels is small and the aberrations are not obvious. At high voltage levels, the discharge horizontal displacement and morphological distortion jumped strongly, and the energy was not easily concentrated. The discharge in the transition stage is always maintained at a high energy level, instead showing the least number of discharges.

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Characterization of Microstructure, Grain Distribution, and Surface Properties of Niti-Based Superelastic Alloy

SSRN

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SSRN 2022年

作者： Yan, Chao Zeng, Qunfeng Khanlari, Khashayar Zhu, Xijing Wang, Zhao Shanxi Key Laboratory of Advanced Manufacturing Technology North University of China Shanxi Taiyuan030051 China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong University Xi’an710049 China The State Key Laboratory of Powder Metallurgy Central South University Changsha410083 China

Hardened 58Ni39Ti3Hf possesses a superior resistance to quenching cracking and spall-type surface fatigue as compared to 60NiTi, which makes it considered as an alternative for this binary intermetallic. Nonetheless, it is still a lack of deep understanding of how the microstructure, grain distribution, and surface properties of 58Ni39Ti3Hf differ from those of 60NiTi. In this work, combined analysis methods of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM) were conducted to systematically characterize the phase composition, microstructure, and grain distribution. Nanoindentation test was carried out to study the mechanical properties of surface. The growth of passive film in seawater was analyzed using X-ray photoelectron spectroscopy (XPS). Finally, electrochemical impedance spectroscopy (EIS) measurement before, during, and after the tribocorrosion test was performed to evaluate the corrosion resistance of these two alloys when served in different conditions. 58Ni39Ti3Hf was found to have better corrosion and mechanical properties than that of 60NiTi within the range of this experiment, and the involved mechanism was discussed in detail. © 2022, The Authors. All rights reserved.

关键词： Microstructure

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Two points are enough

arXiv

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arXiv 2024年

作者： Liu, Hao Zhao, Yanbin Zheng, Huarong Fan, Xiulin Deng, Zhihua Chen, Mengchi Wang, Xingkai Liu, Zhiyang Lu, Jianguo Chen, Jian State Key Laboratory of Fluid Power Components and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou China Ocean College Zhejiang University Hangzhou China State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and Engineering Zhejiang University Hangzhou China Nanyang Technological University Singapore School of Control Science and Engineering Zhejiang University Hangzhou China School of Materials Science and Engineering Tianjin University Tianjin China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

Prognosis and diagnosis play an important role in accelerating the development of lithium-ion batteries, as well as reliable and long-life operation. In this work, we answer an important question: What is the minimum amount of data required to extract features for accurate battery prognosis and diagnosis? Based on the first principle, we successfully extracted the best two-point feature (BTPF) for accurate battery prognosis and diagnosis using the fewest data points (only two) and the simplest feature selection method (Pearson correlation coefficient). The BTPF extraction method is tested on 820 cells from 6 open-source datasets (covering five different chemistry types, seven manufacturers, and three data types). It achieves comparable accuracy to state-of-the-art features in both prognosis and diagnosis tasks. This work challenges the cognition of existing studies on the difficulty of battery prognosis and diagnosis tasks, subverts the fixed pattern of establishing prognosis and diagnosis methods for complex dynamic systems through deliberate feature engineering, highlights the promise of data-driven methods for field battery prognosis and diagnosis applications, and provides a new benchmark for future studies. Copyright © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Numerical Investigation on Condensation-Induced Water Hammer in an Equal-Height-Difference Passive Heat Removal system Under Rolling Conditions

SSRN

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SSRN 2022年

作者： Wang, Zhiwei Duan, Zhongdi He, Yanping Huang, Chao Yuan, Yuchao Liu, Shiwen Li, Mingzhi State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China School of Naval Architecture Ocean & Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Institute of Marine Equipment Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The investigation of condensation-induced water hammer (CIWH) under ocean conditions is crucial to the system safety of the offshore floating nuclear plants (OFNPs). This paper establishes a CIWH numerical model under rolling conditions based on the computational fluid dynamics (CFD) code combined with user-defined functions (UDF). First, the numerical model is verified by published experimental data. Then, the transient behaviors of CIWH events under various rolling parameters are numerically investigated. The results show that the rolling motion causes a significant steam slug and enhances the steam-subcooled water contact area, which promotes the average condensation rate. The average condensation rate increases with an increase in rolling angle, decreases with an increase in rolling period. Due to the larger average condensation rate and reverse flow caused by rolling motion, the pressure peak generated by the CIWH significantly increases compared to static conditions. Similarly, the pressure peak increases as rolling angle increases, decreases as rolling period increase. Moreover, the pressure peak is proportional to steam inlet velocity, and the location of the pressure peak gradually moves back to the outlet direction as the steam velocity increases. These qualitative conclusions are useful to understand the effects of rolling motion on the CIWH and provide a reference for the CIWH simulations. © 2022, The Authors. All rights reserved.

关键词： Condensation

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