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Sporadic metal layers in the upper mesosphere

FARADAY DISCUSSIONS 1995年第 1 期100卷 431-439页

作者： Gardner, CS Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign 315 Computer and Systems Research Laboratory Urbana IL 61801 1308 West Main Street United States

One of the most interesting current problems in the aeronomy of the mesosphere is the origin of sporadic Na (Na-s) and sporadic Fe (Fe-s) layers. These are very thin (ca. 1 km), dense layers of atomic Na and Fe which often form explosively in a matter of minutes, may extend horizontally for several thousand kilometres, persist for several hours, and then disappear rapidly. While the typical concentrations of atomic Na and Fe in the upper mesosphere are respectively, 4 x 10(3) and 10(4) cm(-3), maximum densities exceeding 10(5) cm(-3) have been observed for both species during sporadic layer events. Incoherent scatter radar and lidar observations at Arecibo have shown conclusively that many Na-s layers are linked to the formation of sporadic E (E(s)) layers, while rocket and lidar observations at Andoya have shown a similar link between Fe-s and E(s). Recent lidar observations at Urbana and Hawaii have revealed the simultaneous formation of Na-s, Fe-s, and Ca+ layers and the occurrence of substantial temperature enhancements and wind shears during some Na-s events. We present new observations of Na-s obtained with a Na wind/temperature (W/T) lidar during the recent ALOHA-93 (1993 airborne lidar and observations of the Hawaiian airglow) Campaign in Hawaii. These observations are used to characterize the wind and temperature structure associated with several of the major Na-s events observed during ALOHA-93.

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Secure Communication in Dynamic RDARS-Driven systems

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IEEE Wireless Communications Letters 2025年

作者： Pei, Ziqian Wang, Jintao Zhang, Pingping Shi, Zheng Yang, Guanghua Ma, Shaodan University of Macau Department of Electrical and Computer Engineering State Key Laboratory of Internet of Things for Smart City Macau999078 China Jinan University School of Intelligent Systems Science and Engineering Zhuhai519070 China

In this letter, we investigate a dynamic reconfigurable distributed antenna and reflection surface (RDARS)-driven secure communication system, where the working mode of the RDARS can be flexibly configured. We aim to maximize the secrecy rate by jointly designing the active beamforming vectors, reflection coefficients, and the channel-aware mode selection matrix. To address the non-convex binary and cardinality constraints introduced by dynamic mode selection, we propose an efficient alternating optimization (AO) framework that employs penalty-based fractional programming (FP) and successive convex approximation (SCA) transformations. Simulation results demonstrate the potential of RDARS in enhancing the secrecy rate and show its superiority compared to existing reflection surface-based schemes. © 2012 IEEE.

关键词： Secure communication

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BOUNDARY-VALUE PROBLEMS IN ELECTROFLUIDIZED AND MAGNETICALLY STABILIZED BEDS

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CHEMICAL engineering COMMUNICATIONS 1988年第1期67卷 181-204页

作者： MOISSIS, AA ZAHN, M High Voltage Research Laboratory Laboratory for Electromagnetic and Electronic Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139

The stress balance boundary condition at the free surface of a one dimensional electrofluidized or magnetically stabilized bed is reviewed. Conditions for zero interfacial force balance at the top of the bed are investigated. For the case of a uniformly fluidized bed, it is shown that a nonzero particle collision pressure is necessary for a force free bed surface. For the case where the collision pressure is neglected, it is shown that the electrofluidized or magnetically stabilized bed must be nonuniform at equilibrium. Stability criteria for a semi-infinite bed show that a critical field strength is necessary for stabilization. Below this critical condition the bed is convectively unstable. The temporal and spatial responses of a stabilized bed to small signal variations in superficial gas velocity, electrode position, and applied potential are calculated. Specific attention is directed to sinusoidal time variations in superficial gas velocity, where at low frequencies a standing wave character results for the fluidized bed variables.

关键词： Electrofluidization Magnetically stabilized beds Fiuidization Stabilization Boundary value problems.

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Optics for terawatt-scale photovoltaics: review and perspectives

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Advances in Optics and Photonics 2025年第1期17卷 185-294页

作者： Jäger, Klaus Aeberhard, Urs Llado, Esther Alarcon Bläsi, Benedikt Burger, Sven Ehrler, Bruno Favre, Wilfried Fejfar, Antonín Gageot, Tristan Gordon, Ivan Helmers, Henning Höhn, Oliver Isabella, Olindo Jošt, Marko Ledinský, Martin Mandal, Jyotirmoy Manley, Phillip Muñoz, Delfina Omair, Zunaid Lizcano, Juan Camilo Ortiz Paetzold, Ulrich W. Raman, Aaswath P. Sai, Hitoshi Saive, Rebecca Schmid, Martina Yablonovitch, Eli Becker, Christiane Department Optics for Solar Energy Helmholtz-Zentrum Berlin für Materialien und Energie Kekuléstraße 5 Berlin12489 Germany Computational Nano Optics Zuse Institute Berlin Takustraße 7 Berlin14195 Germany Fluxim AG Katharina-Sulzer-Platz 2 Winterthur8400 Switzerland LMPV-Sustainable Energy Materials Department AMOLF Science Park 104 Amsterdam1098 XG Netherlands Fraunhofer Institute for Solar Energy Systems ISE Heidenhofstraße 2 Freiburg79100 Germany JCMwave GmbH Bolivarallee 22 Berlin14050 Germany Université Grenoble Alpes CEA LITEN Campus INES 50 avenue du Lac Léman Le Bourget-du-Lac73375 France FZU - Institute of Physics The Czech Academy of Sciences Na Slovance 1999/2 Prague 8182 00 Czech Republic IMEC/Energyville Thor Park 8320 Genk3600 Belgium Hasselt University Martelarenlaan 42 Hasselt3500 Belgium Photovoltaic Materials and Devices Laboratory Delft University of Technology Mekelweg 4 Delft2628 CD Netherlands University of Freiburg Emmy-Noether-Str.2 Freiburg79110 Germany Faculty of Electrical Engineering University of Ljubljana Tržaška 25 Ljubljana1000 Slovenia Department of Civil and Environmental Engineering Princeton University E209A Engineering Quadrangle PrincetonNJ08544 United States Department of Electrical Engineering and Computer Sciences University of California BerkeleyCA94720 United States Institute of Microstructure Technology Karlsruhe Institute of Technology Eggenstein-Leopoldshafen76344 Germany Light Technology Institute Karlsruhe Institute of Technology Karlsruhe76131 Germany Department of Materials Science and Engineering University of California Los AngelesCA90095 United States Ibaraki Tsukuba305-8568 Japan MESA+ Institute for Nanotechnology Inorganic Materials Science University of Twente NB Enschede7522 Netherlands University of Duisburg-Essen Forsthausweg 2 Duisburg47057 Germany Faculty 1 School of Engineering – Energy and Information Hochschule für Technik und Wirtschaft Berlin

In this section, we described the various device architectures in production for crystalline-silicon PV as well as the various absorber materials being used and developed for thin-film PV. We also explained why multijunction PV technology is considered the future of PV technology. We identified four major technological challenges (Fig. 1) for future mass production and deployment of PV technology in order to achieve the goal of climate neutrality and indicated how optics could help resolve these challenges. The four main challenges (Fig. 1) are: • Sustainable production of PV systems;• Higher energy conversion efficiencies;• Higher energy output and operational lifetime;• Integration of PV systems in their environment. © 2025 Optica Publishing Group (formerly OSA). All rights reserved.

关键词： Energy conversion efficiency

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On Algebraic Immunity of Trace Inverse Functions on Finite Fields of Characteristic Two

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Journal of systems Science & Complexity 2016年第1期29卷 272-288页

作者： FENG Xiutao GONG Guang Key Laboratory of Mathematics Mechanization Academy of Mathematics and Systems ScienceChinese Academy of Sciences State Key Laboratory of Information Security(Institute of Information Engineering Chinese Academy of Sciences) Department of Electrical and Computer Engineering University of Waterloo

The trace inverse functions Tr(λx^(-1)) over the finite field F_(2~n) are a class of very important Boolean functions and are used in many stream ciphers such as SFINKS,RAKAPOSHI,the simple counter stream cipher(SCSC) presented by Si W and Ding C(2012),*** order to evaluate the security of those ciphers in resistance to(fast) algebraic attacks,the authors need to characterize algebraic properties of Tr(λx^(-1)).However,currently only some bounds on algebraic immunity of Tr(λx^(-1)) are given in the public literature,for example,the NGG upper bound and the Bayev lower bound,*** paper gives the exact value of the algebraic immunity of Tr(λx^(-1)) over F_(2~n),that is,AI(Tr(λx^(-1))) =[2n^(1/2)]- 2,where n ≥ 2,A ∈ F_(2~n) and λ≠ 0,which shows that Dalai's conjecture on the algebraic immunity of Tr(λx^(-1)) is *** is more,the authors demonstrate some weak properties of Tr(λx^(-1)) against fast algebraic attacks.

关键词： Algebraic immunity boolean functions fast algebraic attacks trace inverse functions

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Reducing division latency with reciprocal caches

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Reliable Computing 1996年第2期2.0卷 147-153页

作者： Oberman, Stuart F. Computer Systems Laboratory Department of Electrical Engineering Stanford University Stanford CA United States

Floating-point division is generally regarded as a high latency operation in typical floating-point applications. Many techniques exist for increasing division performance, often at the cost of increasing either chip area, cycle time, or both. This paper presents two methods for reducing the latency of division. Using applications from the SPECfp92 and NAS benchmark suites, these methods are evaluated to determine their effects on overall system performance. The notion of recurring computation is presented, and it is shown how recurring division can be exploited using an additional, dedicated division cache. For multiplication-based division algorithms, reciprocal caches can be utilized to store recurring reciprocals. Results show that reciprocal caches can achieve nearly a two-times speedup in division performance for reasonable cache sizes. © S. F. Oberman, M. J. Flynn, 1996.

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Compact Model Build Upon Dynamic Weighting Artificial Neural Network Approach for Complementary Field Effect Transistors

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IEEE Transactions on Electron Devices 2024年第1期71卷 246-253页

作者： Butola, Rajat Li, Yiming Kola, Sekhar Reddy National Yang Ming Chiao Tung University Parallel and Scientific Computing Laboratory Electrical Engineering and Computer Science International Graduate Program Hsinchu300093 Taiwan Institute of Pioneer Semiconductor Innovation The Institute of Artificial Intelligence Innovation National Yang Ming Chiao Tung University Parallel and Scientific Computing Laboratory Electrical Engineering and Computer Science International Graduate Program The Institute of Communications Engineering the Institute of Biomedical Engineering Department of Electronics and Electrical Engineering Hsinchu300093 Taiwan

In this work, a dynamic weighting-artificial neural network (DW-ANN) methodology is presented for quick and automated compact model (CM) generation. It takes advantage of both TCAD simulations for high accuracy and SPICE simulations for cost-effectiveness. This methodology is developed for gate-all-around (GAA) silicon (Si) nanosheet (NS) complementary field effect transistor (CFET), a potential candidate for future CMOS technology due to its innate properties. The critical process variation (PV) sources that severely degrade the CFET performance are estimated using DW-ANN. It reduces the computation cost and predicts the effects of PV sources with less than 1% error. Furthermore, a compact DW-ANN-based Verilog-A model has been developed that captures the dc as well as transient behavior accurately for circuit-level analysis. CFET-based circuits such as inverter, 6T-static random access memory (SRAM), and ring oscillator (RO) are characterized and implemented using DW-ANN-based CM. The overall average error of the model is reported as less than 2%. Therefore, the proposed device and circuit modeling approach provides a feasible solution for the rapid compact modeling of new emerging devices with good convergence and high accuracy. © 1963-2012 IEEE.

关键词： Neural networks

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Implementing real-time partitioned convolution algorithms on conventional operating systems

Implementing real-time partitioned convolution algorithms on...

引用

14th International Conference on Digital Audio Effects, DAFx 2011

作者： Battenberg, Eric Avižienis, Rimas Parallel Computing Laboratory Department of Electrical Engineering and Computer Science University of California Berkeley CA United States

ISBN: (纸本)9782954035109

We describe techniques for implementing real-time partitioned convolution algorithms on conventional operating systems using two different scheduling paradigms: time-distributed (cooperative) and multi-threaded (preemptive). We discuss the optimizations applied to both implementations and present measurements of their performance for a range of impulse response lengths on a recent high-end desktop machine. We find that while the time-distributed implementation is better suited for use as a plugin within a host audio application, the preemptive version was easier to implement and significantly outperforms the time-distributed version despite the overhead of frequent context switches.

关键词： Impulse response

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Adaptive Fault Detection Scheme Using an Optimized Self-healing Ensemble Machine Learning Algorithm

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CSEE Journal of Power and Energy systems 2022年第4期8卷 1145-1156页

作者： Levent Yavuz Ahmet Soran AhmetÖnen Xiangjun Li S.M.Muyeen Electrical and Computer Engineering Department in Abdullah Gül University Kayseri 38080Turkey Department of Electrical and Computer Engineering College of EngineeringSultan Qaboos UniversityAl-KhoudMuscat123Oman Department of Electrical Engineering Qatar UniversityDoha 2713Qatar State Key Laboratory of Control and Operation of Renewable Energy and Storage Systems China Electric Power Rescarch InstituteBeijing 100192China

This paper proposes a new cost-efficient,adaptive,and self-healing algorithm in real time that detects faults in a short period with high accuracy,even in the situations when it is difficult to *** than using traditional machine learning(ML)algorithms or hybrid signal processing techniques,a new framework based on an optimization enabled weighted ensemble method is developed that combines essential ML *** the proposed method,the system will select and compound appropriate ML algorithms based on Particle Swarm Optimization(PSO)*** this purpose,power system failures are simulated by using the PSCA D-Python *** of the salient features of this study is that the proposed solution works on real-time raw data without using any pre-computational techniques or pre-stored ***,the proposed technique will be able to work on different systems,topologies,or data *** proposed fault detection technique is validated by using PSCAD-Python co-simulation on a modified and standard IEEE-14 and standard IEEE-39 bus considering network faults which are difficult to detect.

关键词： Decision tree(DT) ensemble machine learning algorithm fault detection islanding operation k-Nearest Neighbor(kNN) linear discriminant analysis(LDA) logistic regression(LR) Naive Bayes(NB) self-healing algorithm

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Enhancement of pulsed laser ablation assisted with continuous wave laser irradiation

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Science China(Physics,Mechanics & Astronomy) 2019年第3期62卷 66-74页

作者： Ye Ding LiJun Yang MingHui Hong Key Laboratory of Micro-systems and Micro-structures Manufacturing Ministry of Education Harbin Institute of Technology Department of Electrical and Computer Engineering National University of Singapore School of Mechatronics Engineering Harbin Institute of Technology

Continuous wave(CW) laser irradiation is employed to enhance the pulsed laser ablation of silicon and stainless steel(316 L)samples. Different surface temperatures generated by the CW laser irradiation are set as the initial working circumstance for the pulsed laser ablation. The diameter and depth of laser-ablated craters are measured to study threshold fluence, pulse incubation coefficient and ablation rate under different surface temperatures. Numerical simulation employing Heat Transfer in Solid and Deformed Geometry Interface modules in COMSOL is performed to estimate ablation rate theoretically based on Hertz-Knudsen equation. The realized crater-related data are analyzed to further obtain their dependences on surface temperature. The parametric and morphological studies indicate that the weakened plasma shielding effect and thermal diffusion in the ablated region induced by the CW laser irradiation lead to the enhanced pulsed laser ablation significantly.

关键词： enhanced pulsed laser ablation CW laser irradiation Hertz-Knudsen equation parametric and morphological studies

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