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Metamaterial absorbers realized in an X-band rectangular waveguide

Chinese Physics B 2012年第11期21卷 474-478页

作者：黄勇军文光俊李建钟靖平王平孙元华 O.Gordon 朱卫仁 Key Laboratory of Broadband Optical Fiber Transmission&Communication Networks School of Communication and Information EngineeringUniversity of Electronic Science and Technology of China Advanced Computing and Simulation Laboratory(AχL) Department of Electrical and Computer Systems EngineeringMonash University

In this paper, we demonstrate six types of metamaterial absorbers （MMAs） by measuring their absorptivities in an X-band （8 12 GHz） rectangular waveguide. Some of the MMAs have been demonstrated previously by using the free space measurement method, and the others are proposed firstly in this paper. The measured results show that all of the six MMAs exhibit high absorptivities above 98%, which have similar absorbing characteristics to those measured in the free space. The numerically obtained surface current densities for each MMA show that the absorbing mechanism is the same as that under the free space conditions. Such a demonstration method is superior to the conventional free space measurement method due to the small-scale test samples required, the simple measure device, and its low cost. Most importantly, the proposed method opens a way to enable MMAs to be used in microwave applications such as matched terminations.

关键词： metamaterial absorber electric resonator rectangular waveguide

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PHASE AND FREQUENCY TRACKING ACCURACY IN DIRECT-DETECTION OPTICAL-COMMUNICATION systems

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IEEE TRANSACTIONS ON COMMUNICATIONS 1972年第6期CO20卷 1139-&页

作者： SNYDER, DL RHODES, IB Department of Electrical Engineering and the Biomedical Computer Laboratory Washington University Saint Louis MO USA Laboratory of Control Systems Science and Engineering Washington University Saint Louis MO USA

Lower bounds are given on the attainable mean-square performance in causally tracking the phase and frequency of a subcarrier that modulates an optical carrier in a direct-detection opticalcommunication system.

关键词： Optical modulation Oscillators Stochastic processes Frequency synchronization Phase modulation Intensity modulation Difference equations Gaussian processes Viterbi algorithm Communication system control

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Adjustable and distributionally robust chance-constrained economic dispatch considering wind power uncertainty

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Journal of Modern Power systems and Clean Energy 2019年第3期7卷 658-664页

作者： Xin FANG Bri-Mathias HODGE Fangxing LI Ershun DU Chongqing KANG National Renewable Energy Laboratory GoldenCO80401USA Department of Electrical Engineering and Computer Science The University of TennesseeKnoxvilleTN37996USA State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing100084China

This paper proposes an adjustable and distributionally robust chance-constrained(ADRCC) optimal power flow(OPF) model for economic dispatch considering wind power forecasting uncertainty. The proposed ADRCC-OPF model is distributionally robust because the uncertainties of the wind power forecasting are represented only by their first-and second-order moments instead of a specific distribution assumption. The proposed model is adjustable because it is formulated as a second-order cone programming(SOCP) model with an adjustable *** coefficient can control the robustness of the chance constraints, which may be set up for the Gaussian distribution, symmetrically distributional robustness, or distributionally robust cases considering wind forecasting uncertainty. The conservativeness of the ADRCC-OPF model is analyzed and compared with the actual distribution data of wind forecasting error. The system operators can choose an appropriate adjustable coefficient to tradeoff between the economics and system security.

关键词： Economic dispatch Adjustable and distributionally robust chance-constrained(ADRCC) optimization Wind power forecasting Uncertainty

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Cyber-physical Modeling and Control of Crowd of Pedestrians:A Review and New Framework

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IEEE/CAA Journal of Automatica Sinica 2015年第3期2卷 334-344页

作者： Kecai Cao Yangquan Chen Dan Stuart Dong Yue the College of Automation Nanjing University of Posts and Telecommunications Mechatronics Embedded Systems and Automation Laboratory School of EngineeringUniversity of California the Department of Electrical and Computer Engineering Utah State University

Recent advances in modeling and control of crowd of pedestrians are briefly surveyed in this paper. Possibilities of applying fractional calculus in the modeling of crowd of pedestrians have been shortly reviewed and discussed from different aspects such as descriptions of motion, interactions of long range and effects of memory. Control of the crowd of pedestrians have also been formulated using the framework of cyber-physical systems and been realized using networked Segways with onboard emergency response personnels to regulate the velocity and flux of the crowd. Platform for verification of the theoretical results are also provided in this paper. © 2014 Chinese Association of Automation.

关键词： Calculations Embedded systems

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Mechanical resonant sensing of spin texture dynamics in a two-dimensional antiferromagnet

arXiv

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arXiv 2025年

作者： Yousuf, S.M. Enamul Hoque Wang, Yunong Ramachandran, Shreyas Koptur-Palenchar, John Tarantini, Chiara Xiang, Li McGill, Stephen Smirnov, Dmitry Santos, Elton J.G. Feng, Philip X.-L. Zhang, Xiao-Xiao Department of Electrical & Computer Engineering University of Florida GainesvilleFL32611 United States Institute for Condensed Matter Physics and Complex Systems School of Physics and Astronomy The University of Edinburgh EdinburghEH9 3FD United Kingdom Department of Physics University of Florida GainesvilleFL32611 United States National High Magnetic Field Laboratory TallahasseeFL32312 United States Donostia-San Sebastian20018 Spain Higgs Centre for Theoretical Physics The University of Edinburgh EH9 3FD United Kingdom

The coupling between the spin degrees of freedom and macroscopic mechanical motions, including striction[1], shearing[2], and rotation[3-4], has attracted wide interest with applications in actuation, transduction, and information processing[5-7]. Experiments so far have established the mechanical responses to the long-range ordered[1, 5] or isolated single spin states[8]. However, it remains elusive whether mechanical motions can couple to a different type of magnetic structure, the non-collinear spin textures, which exhibit nanoscale spatial variations of spin (domain walls, skyrmions, etc.) and are promising candidates to realize high-speed computing devices[9-12]. Here, we report the detection of collective spin texture dynamics with nanoelectromechanical resonators made of two-dimensional antiferromagnetic (AFM) MnPS3 with 10-9 strain sensitivity. By examining radio frequency mechanical oscillations under magnetic fields, new magnetic transitions were identified with sharp dips in resonant frequency. They are attributed to the collective AFM domain wall motions as supported by the analytical modeling of magnetostriction and large-scale spin-dynamics simulations. Additionally, an abnormally large modulation in the mechanical nonlinearity at the transition field infers a fluid-like response due to the ultrafast domain motion. Our work establishes a strong coupling between spin texture and mechanical dynamics, laying the foundation for electromechanical manipulation of spin texture and developing quantum hybrid devices. © 2025, CC BY.

关键词： Degrees of freedom (mechanics)

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parallel Dispatch:A New Paradigm of electrical Power System Dispatch

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 311-319页

作者： Jun Jason Zhang Fei-Yue Wang Qiang Wang Dazhi Hao Xiaojing Yang David Wenzhong Gao Xiangyang Zhao Yingchen Zhang Department of Electrical and Computer Engineering Ritchie School of Engineering and Computer Science University of Denver Denver 80210 CO USA State Key Laboratory of Management and Control for Complex Systems Institute of Automation Chinese Academy of Science (SKL-MCCS CASIA) Beijing 100190 China Research Center of Computational Experiments and Parallel Systems The National University of Defense Technology Changsha 410073 China State Grid Tianjin Electric Power Company Tianjin 300010 China School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China National Renewable Energy Laboratory Golden CO 80401 USA IEEE

Modern power systems are evolving into sociotechnical systems with massive complexity, whose real-time operation and dispatch go beyond human capability. Thus,the need for developing and applying new intelligent power system dispatch tools are of great practical significance. In this paper, we introduce the overall business model of power system dispatch, the top level design approach of an intelligent dispatch system, and the parallel intelligent technology with its dispatch applications. We expect that a new dispatch paradigm,namely the parallel dispatch, can be established by incorporating various intelligent technologies, especially the parallel intelligent technology, to enable secure operation of complex power grids,extend system operators' capabilities, suggest optimal dispatch strategies, and to provide decision-making recommendations according to power system operational goals.

关键词： ACP knowledge automation power dispatch parallel dynamic programming parallel intelligence paralle learning situational awareness

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CAMP: A Technique to Estimate Per-Structure Power at Run-time using a Few Simple Parameters

CAMP: A Technique to Estimate Per-Structure Power at Run-tim...

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15th International Symposium on High-Performance computer Architecture

作者： Powell, Michael D. Biswas, Arijit Emer, Joel S. Mukherjee, Shubhendu S. Sheikh, Basit R. Yardi, Shrirang Intel Massachusetts United States Computer Systems Laboratory Cornell University United States Department of Electrical and Computer Engineering Virginia Tech United States

ISBN: (纸本)9781424429325

Microprocessor power has become a first-order constraint at run-time. Designers must employ aggressive power-management techniques at run-time to keep a processors ballooning power requirements under control. Effective power management benefits from knowledge of run-time microprocessor power consumption in both the core and individual microarchitectural structures, such as caches, queues, and execution units. Increasingly feasible per-structure power-control techniques, such as fine-grain clock gating, power gating, and dynamic voltage/frequency scaling (DVFS), become more effective from run-time estimates of per-structure power However, run-time computation of per-structure power estimates based on utilization requires daunting numbers of input statistics, which makes per-structure monitoring of run-time power a challenging problem. To address the challenges of estimating per-structure power in hardware, we propose a new technique, called Common Activity-based Model for Power (CAMP), to estimate activity factors and power for microarchitectural structures. Despite using a relatively few input parameters-specifically nine-based on general microprocessor utilization statistics (e.g., IPC and load rate), our linear-regression-based model estimates activity and dynamic power for over 100 structures in an out-of-order x86 pipeline and core power with an average error of 8%. Because the computations utilize few inputs, CAMP is simple enough to implement in hardware, providing run-time structure and core power estimates for dynamic power management. Because the input statistics are generic in nature and the model remains accurate across incremental microarchitectural refinements, CAMP provides simple intuitive equations relating global microarchitectural statistics to structure activity and power. These equations provide a simple technique that can equate changes in one structure activity to power variations in other structures across the pipeline.

关键词： Pipelines

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GPU accelerated blockchain over key-value database transactions

IET Blockchain

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IET Blockchain 2022年第1期2卷 1-12页

作者： Iliakis, Konstantinos Koliogeorgi, Konstantina Litke, Antonios Varvarigou, Theodora Soudris, Dimitrios Microprocessors and Digital Systems Laboratory Department of Electrical and Computer Engineering National Technical University of Athens Zografou Campous 9 Iroon Polytechniou str Athens Greece Distributed Knowledge and Media Systems group Department of Electrical and Computer Engineering National Technical University of Athens Zografou Campous 9 Iroon Polytechniou str Athens Greece

Blockchain is a distributed ledger based on peer-to-peer networks, originally used for crypto-currency systems. Blockchains are being used as an enabling technology for decentralised applications in the areas of Internet-of-Things, finance, supply-chain and others. Consistency, data privacy, performance, and energy efficiency are of paramount importance in such applications. The full nodes of public, permissionless blockchains undertake the task of verifying the transactions generated by the network. Full nodes perform operations such as confirming balances, transactions, and history, i.e. mostly database search queries. Consequently, their throughput is crucial for the performance of blockchain systems. In this work, the benefits of accelerating the blockchain search and insert queries by leveraging GPU platforms are studied. An extensive comparison between the most dominant utilized database is provided, i.e. LevelDB, and MegaKV, a high-performance GPU-accelerated database. Realistic operations that take place in blockchain systems are emulated and evaluated over representative scenarios, showing three orders of magnitude gains in throughput and energy efficiency without compromising the security aspect. The extensive comparison between LevelDB and MegaKV indicates that GPU acceleration is an effective solution for runtime and energy efficiency enhancement of blockchain systems, and the integration of the two technologies is a promising field of research. © 2022 The Authors. IET Blockchain published by John Wiley & Sons Ltd on behalf of The Institution of engineering and Technology.

关键词： Blockchain

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parallel Planning:A New Motion Planning Framework for Autonomous Driving

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IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 236-246页

作者： Long Chen Xuemin Hu Wei Tian Hong Wang Dongpu Cao Fei-Yue Wang IEEE School of Data and Computer Science Sun Yat-sen University the School of Computer Science and Information Engineering Hubei University Institute of Measurement and Control Systems Karlsruhe Institute of Technology Department of Mechanical and Mechatronics Engineering University of Waterloo the State Key Laboratory of Management and Control for Complex Systems.Institute of Automation Chinese Academy of Sciences the Research Center for Military Computational Experiments and Parallel Systems Technology National University of Defense Technology

Motion planning is one of the most significant technologies for autonomous driving. To make motion planning models able to learn from the environment and to deal with emergency situations, a new motion planning framework called as"parallel planning" is proposed in this paper. In order to generate sufficient and various training samples, artificial traffic scenes are firstly constructed based on the knowledge from the reality.A deep planning model which combines a convolutional neural network(CNN) with the Long Short-Term Memory module(LSTM) is developed to make planning decisions in an end-toend mode. This model can learn from both real and artificial traffic scenes and imitate the driving style of human ***, a parallel deep reinforcement learning approach is also presented to improve the robustness of planning model and reduce the error rate. To handle emergency situations, a hybrid generative model including a variational auto-encoder(VAE) and a generative adversarial network(GAN) is utilized to learn from virtual emergencies generated in artificial traffic scenes. While an autonomous vehicle is moving, the hybrid generative model generates multiple video clips in parallel, which correspond to different potential emergency scenarios. Simultaneously, the deep planning model makes planning decisions for both virtual and current real scenes. The final planning decision is determined by analysis of real observations. Leveraging the parallel planning approach, the planner is able to make rational decisions without heavy calculation burden when an emergency occurs.

关键词： Autonomous driving artificial traffic scene deep learning emergencies motion planning parallel planning

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Kalman-filtering timing recovery scheme for orthogonal frequency domain multiplexing (OFDM) systems 25

Kalman-filtering timing recovery scheme for orthogonal frequ...

引用

25th IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2000

作者： Hajirostam, Mohamad Maddah-Ali, M.A. Haft-Baradaran, A. Kilani, M.T. Fakhraie, S.M. Sharif-Khani, M. Shoaei, O. VLSI Circuits and Systems Laboratory Department of Electrical and Computer Engineering University of Tehran Tehran Iran

ISBN: (纸本)0780362934

This paper describes a new technique for timing synchronization in orthogonal frequency domain multiplexing (OFDM) transceiver systems. The proposed technique is based on non-synchronized sampling rate and no pilot is required to be transmitted. Therefore the transmission capacity is increased. The proposed algorithm employs the angles of the received symbols in the OFDM subchannels and provides a computationally efficient technique for estimation of the timing error. An equivalent state space model is also derived for timing error and then Kalman filtering method is exploited for tracking purposes. The proposed technique is very robust, particularly under low signal to noise ratio conditions and has been verified by means of computer simulations. © 2000 IEEE.

关键词： Timing circuits

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