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Low C/N_0 Carrier Tracking Loop Based on Optimal Estimation Algorithm in GPS Software Receivers

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Chinese Journal of Aeronautics 2010年第1期23卷 109-116页

作者： miao jianfeng Chen Wu Sun Yongrong Liu Jianye Navigation Research Center College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016 China Department of Land Surveying and Geo-informatics Hong Kong Polytechnic UniversityHong Kong China

Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C/No ）. This article proposes and analyzes an improved Kalman-filter-based PLL to process weak carrier signals in GPS software receivers. After reviewing the optimal-bandwidth-based traditional second-order PLL, a Kalman-filter-based estimation algorithm is implemented for the new PLL by decorrelating the model error noises and the measurement noises. Finally,the efficiency of this new Kalman-filter-based PLL is verified by experimental data. Compared to the traditional second-order PLL, this new PLL is in position to make correct estimation of the carrier phase differences and Doppler shifts with less overshoots and noise disturbances and keeps an effective check on the disturbances out of jitter noises in PLL. The results show that during processing normal signals,this improved PLL reduces the standard deviation from 0. 010 69 cycle to 0. 007 63 cycle, and for weak signal processing,the phase jitter range and the Doppler shifts can be controlled within ± 17° and ±5 Hz as against ±25° and ＋ 15 Hz by the traditional PLL.

关键词： global positioning system signal processing Kalman filters software radio phase locked loop

Design and realization of synchronization circuit for GPS software receiver based on FPGA

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Journal of Systems Engineering and Electronics 2010年第1期21卷 20-26页

作者： Xiaolei Yu Yongrong Sun Jianye Liu jianfeng miao Navigation Research Center Nanjing University of Aeronautics and Astronautics Nanjing 210016 E R. China Faculty of Science and Technology Deakin University Geelong VIC 3217 Australia Department of Land Surveying & Geo-Informatics Hong Kong Polytechnic University Hong Kong E R. China

With research on the carrier phase synchronization and symbol synchronization algorithm of demodulation module, a synchronization circuit system is designed for GPS software receiver based on field programmable gate array （FPGA）, and a series of experiment is done on the hardware platform. The result shows the all-digital synchronization and demodulation of GPS intermediate frequency （IF） signal can be realized and applied in embedded real-time GPS software receiver system. It is verified that the decision-directed joint tracking algorithm of carrier phase and symbol timing for received signals from GPS is reasonable. In addition, the loop works steadily and can be used for receiving GPS signals using synchronous demodulation. The synchronization circuit for GPS software receiver designed based on FPGA has the features of low cost, miniaturization, low power and real-time. Surely, it will become one of the development directions for GPS and even GNSS embedded real-time software receiver.

关键词： software receiver synchronization circuit field programmable gate army GPS joint tracking algorithm.

基于GA-PSO-BP与灰色关联的光伏短期功率预测

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电力与能源 2024年第2期45卷 219-227页

作者：孙玉波涂承谦李斌缪健锋国网福建省电力有限公司宁德供电公司福建宁德352100

光伏功率预测本身是一个较为复杂的非线性问题,为此首先介绍了在一般情况下影响光伏发电功率预测的客观因素,然后根据客观影响因素进行灰色关联度分析,把预测日作为参考,找到满足条件的日期作为训练样本。针对反向传播(BP)神经网络易于... 详细信息

光伏功率预测本身是一个较为复杂的非线性问题,为此首先介绍了在一般情况下影响光伏发电功率预测的客观因素,然后根据客观影响因素进行灰色关联度分析,把预测日作为参考,找到满足条件的日期作为训练样本。针对反向传播(BP)神经网络易于陷入局部极值的问题,利用粒子群优化(PSO)算法与遗传算法(GA)融合寻优,将粒子群中最优粒子进行排序,对高适应度粒子进行重组,反之进行变异;同时引入莱维飞行与随机游动策略增强算法跳出局部最优的能力,加入自适应权重因子平衡算法的探索与寻优能力。仿真实例证明,在不同的天气条件下,GA-PSO-BP模型与BP、PSO-BP、极限学习机(ELM)模型相比,预测效果更好,预测误差更小。

关键词：光伏功率预测粒子群优化遗传算法灰色关联

Efficient privacy-preserving federated learning under dishonest-majority setting

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Science China(Information Sciences) 2024年第5期67卷 323-324页

作者： Yinbin miao Da KUANG Xinghua LI Tao LENG Ximeng LIU jianfeng MA School of Cyber Engineering Xidian University Intelligent Policing Key Laboratory of Sichuan Province Sichuan Police College Institute of Information Engineering Chinese Academy of Sciences School of Cyber Security University of Chinese Academy of Sciences Key Laboratory of Information Security of Network Systems Fuzhou University

Federated learning(FL) is an emerging distributed learning paradigm that solves the problem of isolated data by jointly learning the global model through distributed ***, recent studies have shown that FL may not always guarantee sufficient privacy preservation, this is mainly because the model parameters(e.g., weights or gradients)may leak sensitive information to malicious adversaries.

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Kinetics-controlled growth SnO2 nanorod arrays for superior rate performance of aligned mesocrystalline lithium-ion batteries with

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Nano Research 2013年第4期6卷 243-252页

作者： Shuai Chen miao Wang jianfeng Ye Jinguang Cai Yurong Ma Henghui Zhou Limin Qi Beijing National Laboratory for Molecular Sciences State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesCollege of Chemistry Peking University Beijing 100871 China

A general method for facile kinetics-controlled growth of aligned arrays of mesocrystalline SnO2 nanorods on arbitrary substrates has been developed by adjusting supersaturation in a unique ternary solvent system comprising acetic acid, ethanol and water. The hydrolysis processes of Sn（IV） as well as the nucleation and growth of SnO2 crystals were carefully controlled in the mixed solvents, leading to an exclusively heterogeneous nucleation on a substrate and the subsequent growth into mesocrystalline nanorod arrays. In particular, aligned arrays of hierarchically structured, [001]-oriented mesocrystalline SnO2 nanorods with four {110} lateral facets can be readily grown on Ti foil as well as many other inert substrates such as fluoride-doped tin oxide （FTO）, Si, graphite, and polytetrafluoroethylene （Teflon）. Due to the unique combination of the mesocrystalline structure and the one-dimensional nanoarray structure, the obtained mesocrystalline SnO2 nanorod arrays grown on metallic Ti substrate exhibited an excellent rate performance with a high initial Coulombic efficiency of 65.6% and a reversible capacity of 720 mA.h/g at a charge/discharge rate of 10 C （namely, 7,820 mA/g） when used as an anode material for lithium-ion batteries.

关键词： tin dioxide nanostructures mesocrystals hierarchical structures lithium-ion batteries

SOLVING SYSTEMS OF PHASELESS EQUATIONS VIA RIEMANNIAN OPTIMIZATION WITH OPTIMAL SAMPLING COMPLEXITY

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Journal of Computational Mathematics 2024年第3期42卷 755-783页

作者： jianfeng Cai Ke Wei Department of Mathematics Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong SARChina School of Data Science Fudan UniversityShanghaiChina

A Riemannian gradient descent algorithm and a truncated variant are presented to solve systems of phaseless equations|Ax|^(2)=*** algorithms are developed by exploiting the inherent low rank structure of the problem based on the embedded manifold of rank-1 positive semidefinite *** recovery guarantee has been established for the truncated variant,showing that the algorithm is able to achieve successful recovery when the number of equations is proportional to the number of *** key ingredients in the analysis are the restricted well conditioned property and the restricted weak correlation property of the associated truncated linear *** evaluations show that our algorithms are competitive with other state-of-the-art first order nonconvex approaches with provable guarantees.

关键词： Phaseless equations Riemannian gradient descent Manifold of rank-1 and positive semidefinite matrices Optimal sampling complexity

Limit state analysis of rigid retaining structures against seismically induced passive failure in heterogeneous soils

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1095-1105页

作者： jianfeng Zhou Changbing Qin College of Civil Engineering Huaqiao UniversityXiamen362021China School of Civil Engineering Chongqing UniversityChongqing400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqing400045China

Soils are not necessarily uniform and may present linearly varied or layered characteristics,for example the backfilled soils behind rigid retaining *** the presence of large lateral thrust imposed by arch bridge,passive soil failure is possible.A reliable prediction of passive earth pressure for the design of such wall is challenging in complicated soil strata,when adopting the conventional limit analysis *** order to overcome the challenge for generating a kinematically admissible velocity field and a statically allowable stress field,finite element method is incorporated into limit analysis,forming finiteelement upper-bound(FEUB)and finite-element lower-bound(FELB)***-static,original and modified pseudo-dynamic approaches are adopted to represent seismic acceleration *** generating feasible velocity and stress fields within discretized elements based on specific criteria,FEUB and FELB formulations of seismic passive earth pressure(coefficient K_(P))can be derived from work rate balance equation and stress *** to an interior point algorithm,optimal upper and lower bound solutions are *** proposed FEUB and FELB procedures are well validated by limit equilibrium as well as lower-bound and kinematic *** studies are carried out to investigate the effects of influential factors on seismic K_(P).Notably,true solution of K_(P) is well estimated based on less than 5%difference between FEUB and FELB solutions under such complex scenarios.

关键词： Retaining wall Passive earth pressure Earthquakes Finite-element limit-analysis methods

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关于农村校长教育管理能力建设的思考

中共福建省委党校学报 2010年第5期 88-92页

作者：缪剑峰宁德市教师进修学院福建宁德352100

提升农村校长教育管理能力,对促进教育均衡发展具有重要意义。文章在分析农村校长教育管理能力建设具体内容的基础上,对农村校长教育管理能力的提升策略进行探讨。

关键词：农村校长教育管理能力内容策略

Tripartite motif-containing protein 11(TRIM11):a novel weapon against Alzheimer’s disease

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Signal Transduction and Targeted Therapy 2024年第2期9卷 339-340页

作者： Yichu Fu Bi Zhang jianfeng Liu College of Life Science and Technology Key Laboratory of Molecular Biophysics of MOEHuazhong University of Science and TechnologyWuhanHubei 430074China

In a recent study published in Science,Zhang et *** that tripartite motif-containing(TRIM)protein 11(TRIM11)exhibited strong inhibition on tau aggregation,which is a pathological characteristic of tauopathies including Alzheimer’s disease(AD).1 This makes TRIM11 a promising novel target for the treatment of AD and other tauopathies.

关键词： Alzheimer tau TRIM