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Proceedings of the 60th Annual ACM/IEEE design Automation Conference

作者： Qinghai Liu Qinfei Tang Jiarui Chen Chuandong Chen Ziran Zhu Huan He Jianli Chen Yao-Wen Chang Center for Discrete Mathematics Fuzhou University Fuzhou China and Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou China Center for Discrete Mathematics Fuzhou University Fuzhou China College of Computer and Date Science Fuzhou University Fuzhou China Department of Microelectronics Fuzhou University Fuzhou China Department of Microelectronics Southeast University Nanjing China Hangzhou Huawei Enterprises Telecommunication Technologies Co. Ltd Hangzhou China State Key Lab of ASIC & System Fudan University Shanghai China Graduate Institute of Electronics Engineering National Taiwan University Taipei Taiwan and Department of Electrical Engineering National Taiwan University Taipei Taiwan

ISBN: (纸本)9798350323481

PCB routing becomes time-consuming as the complexity of PCB design increases. Unlike traditional schemes that treat the two essential PCB routing processes separately, namely, escape and bus routing, we consider the continuity between them and present a golden-pin-based routing scheme to find the desired solution with angle and topology constraints. Further, conventional rip-up and reroute methods are often ineffective and inefficient for congestion alleviation and routability optimization. We construct a component graph by modeling components as vertices and applying the minimum weight vertex covering method to improve the routability. A self-adaptable ordering method is presented for escape routing to arrange the pin order on the component boundary, guaranteeing successful bus routing. In addition, escape routing is performed based on a disjoint path method. We construct a dynamic Hanan grid in bus routing and utilize a novel congestion adjustment technique to improve solution quality. Compared with FreeRouting and Allegro, the experiment results show that our algorithm achieves high routability and a significant 90% runtime reduction.

关键词： escape routing

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On-edge multi-task transfer learning: Model and practice with data-driven task allocation

arXiv

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arXiv 2021年

作者： Zheng, Zimu Chen, Qiong Hu, Chuang Wang, Dan Liu, Fangming The National Engineering Research Center for Big Data Technology and System Key Laboratory of Services Computing Technology and System Ministry of Education School of Computer Science and Technology Huazhong University of Science and Technology Wuhan China The Edge Cloud Innovation Lab. Technical Innovation Department Cloud BU Huawei Technologies Co. Ltd. Shenzhen China The Department of Computing Hong Kong Polytechnic University Kowloon Hong Kong Hong Kong

On edge devices, data scarcity occurs as a common problem where transfer learning serves as a widely-suggested remedy. Nevertheless, transfer learning imposes heavy computation burden to the resource-constrained edge devices. Existing task allocation works usually assume all submitted tasks are equally important, leading to inefficient resource allocation at a task level when directly applied in Multi-task Transfer Learning (MTL). To address these issues, we first reveal that it is crucial to measure the impact of tasks on overall decision performance improvement and quantify task importance. We then show that task allocation with task importance for MTL (TATIM) is a variant of NP-complete Knapsack problem, where the complicated computation to solve this problem needs to be conducted repeatedly under varying contexts. To solve TATIM with high computational efficiency, we propose a Data-driven Cooperative Task Allocation (DCTA) approach. Finally, we evaluate the performance of DCTA by not only a trace-driven simulation, but also a new comprehensive real-world AIOps case study which bridges model and practice via a new architecture and main components design within AIOps system. Extensive experiments show that our DCTA reduces 3.24 times of processing time, and saves 48.4% energy consumption compared with the state-of-the-art when solving TATIM. Copyright © 2021, The Authors. All rights reserved.

关键词： Energy utilization

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Feasibility Analysis of Superconducting MHD Propeller for Vessel Propulsion

Feasibility Analysis of Superconducting MHD Propeller for Ve...

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International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD

作者： Yu Wang Xiwen Yu Youxing Xiong Wen Huang Junquan Chen National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan China

ISBN: (数字)9781728152158

ISBN: (纸本)9781728152165

In this paper, mathematical models for three types of MHD propeller are built. And they are used to achieve the most efficient propeller with the given design constraints. Based on the design result and current status of practical magnet technology, we can infer that it is very difficult for these three types of MHD propeller to be used practically.

关键词： Propellers Magnetohydrodynamics Superconducting magnets Electrodes Superconductivity Magnetoacoustic effects Magnetic shielding

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design of an Inductor-Integrated Transformer Applied to Inverter Power Supply

Design of an Inductor-Integrated Transformer Applied to Inve...

引用

Electrical Engineering (CIYCEE), IEEE China International Youth Conference on

作者： Xinsheng Zhang Ruitian Wang Fei Xiao Guisheng Jie Xujie Lou Beichao Yang National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan China

ISBN: (数字)9781728196596

ISBN: (纸本)9781728196602

The cascaded H-bridges with carrier phase-shift SPWM can increase the equivalent switching frequency and improve the output voltage quality. When the cascaded H-bridges topology is applied to the line-frequency inverter power supply, the bulky magnetic components limit the power density of the power supply. This paper integrates the isolation transformers and filter inductors in the power supply, and develops an optimization design method of the transformer. Through integration and optimization design, the volume power density of the transformer is increased by 69.6%, and the weight power density is increased by 44.8%.

关键词： Power system measurements Power supplies Density measurement Windings Inverters Inductors Optimization

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The grassland carbon cycle:Mechanisms,responses to global changes,and potential contribution to carbon neutrality

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Fundamental Research 2023年第2期3卷 209-218页

作者： Lingli Liu Emma J.Sayer Meifeng Deng Ping Li Weixing Liu Xin Wang Sen Yang Junsheng Huang Jie Luo Yanjun Su JoséM.Grünzweig Lin Jiang Shuijin Hu Shilong Piao State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China Lancaster Environment Centre Lancaster UniversityLancaster LA14YQUnited Kingdom Department of Evolutionary Biology and Environmental Studies University of ZurichZurich 8057Switzerland Institute of Plant Sciences and Genetics in Agriculture The Robert H.Smith Faculty of AgricultureFood and EnvironmentThe Hebrew University of JerusalemRehovot 7610001Israel School of Biological Sciences Georgia Institute of Technology310 Ferst DriveAtlantaGA 30332United States Department of Plant Pathology North Carolina State UniversityRaleighNC 27607United States Sino-French Institute for Earth System Science College of Urban and Environmental SciencePeking UniversityBeijing 100871China National Hulunber Grassland Ecosystem Observation and Research Station Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China

Grassland is one of the largest terrestrial biomes,providing critical ecosystem services such as food production,biodiversity conservation,and climate change *** climate change and land-use intensification have been causing grassland degradation and desertification *** one of the primary medium for ecosystem energy flow and biogeochemical cycling,grassland carbon(C)cycling is the most fundamental process for maintaining ecosystem *** this review,we first summarize recent advances in our understanding of the mechanisms underpinning spatial and temporal patterns of the grassland C cycle,discuss the importance of grasslands in regulating inter-and intra-annual variations in global C fluxes,and explore the previously unappreciated complexity in abiotic processes controlling the grassland C balance,including soil inorganic C accumulation,photochemical and thermal degradation,and wind *** also discuss how climate and land-use changes could alter the grassland C balance by modifying the water budget,nutrient cycling and additional plant and soil ***,we examine why and how increasing aridity and improper land use may induce significant losses in grassland C ***,we identify several priorities for future grassland C research,including improving understanding of abiotic processes in the grassland C cycle,strengthening monitoring of grassland C dynamics by integrating ground inventory,flux monitoring,and modern remote sensing techniques,and selecting appropriate plant species combinations with suitable traits and strong resistance to climate fluctuations,which would help design sustainable grassland restoration strategies in a changing climate.

关键词： Climate changes Land-use change Soil Biotic and abiotic interactions Grassland degradation Grassland restoration Carbon accounting Carbon storage and sequestration mechanisms

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Measurement of Equivalent Electrical Conductivity of Carbon Fiber Sleeve

Measurement of Equivalent Electrical Conductivity of Carbon ...

引用

International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD

作者： Xiwen Yu Youxing Xiong Yu Wang Junquan Chen Dong Wang National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan China

ISBN: (数字)9781728152158

ISBN: (纸本)9781728152165

In this paper, a method for measuring electrical conductivity of the carbon fiber sleeve is introduced. Different from traditional method using the bar, the ring shaped specimen is adopted, where eddy current is induced and flows in the closed loop. An air-gapless reactor was designed, based on this, the reactor was given a sinusoidal excitation with a certain frequency and different amplitudes. By separating the joule loss from the measured total loss, the equivalent electrical conductivity along the circumferential direction can be computed according to the theoretical formula. The result is validated by a finite element model established in Ansoft/Maxwell 3D.

关键词： Loss measurement Carbon Conductivity Current measurement Magnetic separation Magnetic cores Eddy currents

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Optimization design of the reactor coolant pump flywheel comprised of multi-ring packing heavy metal alloy

引用

Journal of Physics: Conference Series 2021年第1期1777卷

作者： L Jiang C W Wu X J Shao Y Zhang M D Yu National Key Laboratory of Science and Technology on Reactor System Design Technology Nuclear Power Institute of China Chengdu 610041 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China

To improve energy storage performance of the multi-ring RCP flywheel comprised of inner hub, tungsten alloy ring and outer retainer, optimization design process for the radial thicknesses of components and interference fit assembly is demonstrated. Radial thicknesses of these components and magnitude of interference fit are set as design parameters to construct parametric analysis model. design of experiments (DOE) technique is adopted to generate design matrix for sensitive analysis. Subsequently, radial basis function (RBF) approximation is employed to search for the optimal design considering structural integrity requirement. Finally, a proper range of the magnitude of interference fit is obtained which can not only prevent neither slippage nor separation between the inner hub and tungsten alloy ring but also ensure the safety of structural strength. In addition, it is found that to ensure a high moment of inertia and energy density, a reasonable large radial thickness of tungsten alloy ring and a reasonable small radial thickness of outer retainer are required.

关键词：

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ARS: Reducing F2FS Fragmentation for Smartphones using Decision Trees

ARS: Reducing F2FS Fragmentation for Smartphones using Decis...

引用

design, Automation and Test in Europe Conference and Exhibition

作者： Lihua Yang Fang Wang Zhipeng Tan Dan Feng Jiaxing Qian Shiyun Tu Wuhan National Laboratory for Optoelectronics Key Laboratory of Information Storage System Engineering Research Center of Data Storage Systems and Technology Huazhong University of Science & Technology

ISBN: (数字)9783981926347

ISBN: (纸本)9781728144689

As we all know, file and free space fragmentation negatively affect file system performance. F2FS is a file system designed for flash memory. However, it suffers from severe fragmentation due to its out-of-place updates and the highly synchronous, multi-threaded writing behaviors of mobile applications. We observe that the running time of fragmented files is 2.36× longer than that of continuous files and that F2FS's in-place update scheme is incapable of reducing fragmentation. A fragmented file system leads to a poor user experience.(p)(/p)Reserving space to prevent fragmentation is an intuitive approach. However, reserving space for all files wastes space since there are a large number of files. To deal with this dilemma, we propose an adaptive reserved space (ARS) scheme to choose some specific files to update in the reserved space. How to effectively select reserved files is critical to performance. We collect file characteristics associated with fragmentation to construct data sets and use decision trees to accurately pick reserved files. Besides, adjustable reserved space and dynamic reservation strategy are adopted. We implement ARS on a Hikey960 development platform and a commercial smartphone with slight space and file creation time overheads. Experimental results show that ARS reduces file and free space fragmentation dramatically, improves file I/O performance and reduces garbage collection overhead compared to traditional F2FS and F2FS with in-place updates. Furthermore, ARS delivers up to 1.26× transactions per second under SQLite than traditional F2FS and reduces running time of realistic workloads by up to 41.72% than F2FS with in-place updates.

关键词： Smart phones Performance evaluation Facebook Twitter Decision trees Writing Databases

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Intelligent Reflecting Surface for MIMO VLC: Joint design of Surface Configuration and Transceiver Signal Processing

arXiv

引用

arXiv 2022年

作者： Sun, Shiyuan Yang, Fang Song, Jian Zhang, Rui Department of Electronic Engineering Beijing National Research Center for Information Science and Technology Tsinghua University Beijing100084 China Key Laboratory of Digital TV System of Guangdong Province and Shenzhen City Research Institute of Tsinghua University in Shenzhen Shenzhen518057 China Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore School of Science and Engineering The Chinese University of Hong Kong Shenzhen518172 China

With the capability of reconfiguring the wireless electromagnetic environment, intelligent reflecting surface (IRS) is a new paradigm for designing future wireless communication systems. In this paper, we consider optical IRS for improving the performance of visible light communication (VLC) under a multiple-input and multiple-output (MIMO) setting. Specifically, we focus on the downlink communication of an indoor MIMO VLC system and aim to minimize the mean square error (MSE) of demodulated signals at the receiver. To this end, the MIMO channel gain of the IRS-aided VLC is first derived under the point source assumption, based on which the MSE minimization problem is then formulated subject to the emission power constraints. Next, we propose an alternating optimization algorithm, which decomposes the original problem into three subproblems, to iteratively optimize the IRS configuration, the precoding and detection matrices for minimizing the MSE. Moreover, theoretical analysis on the performance of the proposed algorithm in high and low signal-to-noise ratio (SNR) regimes is provided, revealing that the joint optimization process can be simplified in such special cases, and the algorithm’s convergence property and computational complexity are also discussed. Finally, numerical results show that IRS-aided schemes significantly reduce the MSE as compared to their counterparts without IRS, and the proposed algorithm outperforms other baseline schemes. Copyright © 2022, The Authors. All rights reserved.

关键词： Mean square error

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Numerical analyses and experimental verification on multiphase flow measurements using a gamma-ray densitometer with blind-tee mixing 27

Numerical analyses and experimental verification on multipha...

引用

27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Ma, Yugao Cui, Yinghuan Hao, Yisheng Huang, Shanfang Pan, Yanzhi Yu, Hongxing Department of Engineering Physics Tsinghua University Beijing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9784888983051

Gas-liquid two-phase flow widely exists in nuclear industry, where the heat flux is quite high. Accurate predictions of key parameters such as void fraction and gas volume fraction are important to the insurance of reactor safety operation. However, the accuracy of most multiphase flowmeters is flow-pattern dependent. A common way to homogenize the gas-liquid mixture and to eliminate the flow pattern effects is to install a blind-tee upstream of the flow measurement section to transform the horizontal flow to vertical upward flow. It is therefore of great interest to verify the effectiveness of flow mixing caused by blind-tee via experiments or simulation. In this study, the three-dimensional transient numerical simulation on gas-liquid two-phase flow was carried out by a commercial CFD software Fluent, using VOF model as multiphase model and Realizable k-Ε model as turbulence model. The results show that the flow develops from centrifugal flow to homogenous flow after passing around the bend and recovers its intermittent nature further downstream. CFD simulation analysis shows that there is a relatively ideal mixing effect after about 7 pipe diameters downstream. Therefore, the complexity of horizontal flow and intermittent flow are avoided by means of device design and measurement position optimization, which simplifies the measurement and calculation model. A flow-pattern based flow rate model is established by introducing the homogeneous-degree evaluation factor. The formula is simple and yet accurate. The relative average error of the model for predicting the total mass flow rate is within 2.66%. Copyright © 2018-2019 by JSME

关键词： Flowmeters

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