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Congruences for finite triple harmonic sums

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 946-948页

作者： FU Xu-dan zhou xia CAi Tian-xin Department of Mathematics Zhejiang University Hangzhou 310028 China hangzhou Foreign Language School Hangzhou 310023 China

Zhao （2003a） first established a congruence for any odd prime p〉3, S（1,1,1 ;p）=-2Bp-3 （mod p）, which holds when p=3 evidently. in this paper, we consider finite triple harmonic sum S（α,β, γ,ρ）（modp） is considered for all positive integers α,β, γ. We refer to w=α＋β＋ γ as the weight of the sum, and show that if w is even, S（α,β, γ,ρ）=0 （mod p） for p≥w＋3; if w is odd, S（α,β, γ,ρ）=-rBp-w （mod p） for p≥w, here r is an explicit rational number independent ofp. A congruence of Catalan number is obtained as a special case.

关键词： Finite triple harmonic sums Recursive relation Bernoulli numbers Catalan numbers

Security-Enhanced Directional Modulation Based on Two-Dimensional M-WFRFT

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China Communications 2024年第5期21卷 229-248页

作者： zhou Zhuang Luo Junshan Wang Shilian xia Guojiang School of Electronic Science National University of Defense TechnologyChangsha 410073China Beijing institute of Astronautical Systems Engineering Beijing 100076China

Directional modulation(DM)is one of the most promising secure communication ***,when the eavesdropper is co-located with the legitimate receiver,the conventional DM has the disadvantages of weak anti-scanning capability,anti-deciphering capability,and low secrecy *** response to these problems,we propose a twodimensional multi-term weighted fractional Fourier transform aided DM scheme,in which the legitimate receiver and the transmitter use different transform terms and transform orders to encrypt and decrypt the confidential *** order to further lower the probability of being deciphered by an eavesdropper,we use the subblock partition method to convert the one-dimensional modulated signal vector into a twodimensional signal matrix,increasing the confusion of the useful *** results demonstrate that the proposed DM scheme not only provides stronger anti-deciphering and anti-scanning capabilities but also improves the secrecy rate performance of the system.

关键词： bit error rate directional modulation phased array secrecy rate weighted fractional Fourier transform

Multi-Agent Few-Shot Meta Reinforcement Learning for Trajectory Design and Channel Selection in UAV-Assisted Networks

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China Communications 2022年第4期19卷 166-176页

作者： Shiyang zhou Yufan Cheng xia Lei huanhuan Duan National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China

Unmanned aerial vehicle(UAV)-assisted communications have been considered as a solution of aerial networking in future wireless networks due to its low-cost, high-mobility, and swift features. This paper considers a UAV-assisted downlink transmission,where UAVs are deployed as aerial base stations to serve ground users. To maximize the average transmission rate among the ground users, this paper formulates a joint optimization problem of UAV trajectory design and channel selection, which.is NP-hard and non-convex. To solve the problem, we propose a multi-agent deep Q-network(MADQN) ***, the agents that the UAVs act as perform actions from th.ir observations distributively and share the same reward. To tackle the tasks where the experience is insufficient, we propose a multi-agent meta reinforcement learning algorithm to fast adapt to the new tasks. By pretraining the tasks with similar distribution, the learning model can acquire general knowledge. Simulation results have indicated the MADQN scheme can achieve higher throughput than fixed allocation. Furthermore, our proposed multiagent meta reinforcement learning algorithm learns the new tasks much faster compared with the MADQN scheme.

关键词： UAV trajectory design channel selection MADQN meta reinforcement learning

Consolidation of partially saturated ground improved by impervious column inclusion:Governing equations and semi-analytical solutions

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Journal of Rock Mechanics and Geotech.ical Engineering 2022年第3期14卷 837-850页

作者： Lei Wang Annan zhou Yongfu Xu xiaohe xia School of Urban Railway Transportation Shanghai University of Engineering ScienceShanghai201620China Civil and infrastructure Engineering Discipline School of EngineeringRMIT UniversityMelbourne3001Australia Department of Civil Engineering Shanghai Jiao Tong UniversityShanghai200240China

This study focuses on the consolidation behavior and mathematical interpretation of partially-saturated ground improved by impervious column *** constitutive relations for soil skeleton,pore air and pore water for partially saturated soils are proposed in the context of partially-saturated ground improved by impervious column *** equation and dissipation equations of excess pore air/water pressures for a partially saturated improved ground are then *** semi-analytical solutions for ground settlement and pore pressure dissipation are then obtained through the Laplace transform and validated by the existing solutions for two special cases in the literature and the numerical results obtained from the finite difference method.A series of parametric studies is finally conducted to investigate the influence of some key factors on consolidation of partially saturated ground improved by impervious column *** on the parametric study,it can be found that a higher value of the area replacement ratio or modulus of the pile results in a longer dissipation time of excess pore air pressure(PAP),a shorter dissipation time of excess pore water pressure(PWP),and a lower normalized settlement.

关键词： Semi-analytical solution Consolidation Partially saturated soil Ground improvement impervious column inclusion

LDA-iD:An LDA-Based Framework for Real-Time Network intrusion Detection

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China Communications 2023年第12期20卷 166-181页

作者： Weidong zhou Shengwei Lei Chunhe xia Tianbo Wang Key Laboratory of Beijing Network Technology Beihang UniversityBeijing 100191China School of Cyber Science and Technology Beihang UniversityBeijing 100191China

Network intrusion poses a severe threat to the ***,existing intrusion detection models cannot effectively distinguish different intrusions with high-degree feature *** addition,efficient real-time detection is an urgent *** address the two above problems,we propose a Latent Dirichlet Allocation topic model-based framework for real-time network intrusion Detection(LDA-iD),consisting of static and online *** problem of feature overlap is transformed into static LDA-iD topic number optimization and topic ***,the detection is based on the latent topic *** achieve efficient real-time detection,we design an online computing mode for static LDA-iD,in which a parameter iteration method based on momentum is proposed to balance the contribution of prior knowledge and new ***,we design two matching mechanisms to accommodate the static and online LDA-iD,*** results on the public NSL-KDD and UNSW-NB15 datasets show that our framework gets higher accuracy than the others.

关键词： feature overlap LDA-iD optimal topic number determination real-time intrusion detection

Amino acids in piglet diarrhea:Effects,mechanisms and insights

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Animal Nutrition 2024年第1期16卷 267-274页

作者： Xihong zhou Jing Liang xia Xiong Yulong Yin Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureThe Chinese Academy of SciencesChangsha 410125China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100049China

Piglet diarrhea is among one of the most serious health problems faced by the pig industry,resulting in significant economic *** disease in piglets has a multifactorial etiology that is affected by physiology,environment,and management *** is the most apparent symptom of intestinal *** a key class of essential nutrients in the piglet diet,amino acids confer a variety of beneficial effects on piglets in addition to being used as a substrate for protein synthesis,including maintaining appropriate intestinal integrity,permeability and epithelial renewal,and alleviating morphological damage and inflammatory and oxidative ***,provision of appropriate levels of amino acids could alleviate piglet *** amino acid effects are mediated by metabolites,gut microbes,and related signaling *** this review,we summarize the current understanding of dietary amino acid effects on gut health and diarrhea incidence in piglets,and reveal the mechanisms *** also provide ideas for using amino acid blends and emphasize the importance of amino acid balance in the diet to prevent diarrhea in piglets.

关键词： Piglet Amino acid Diarrhea Gut microbe immune

high thermal stability and blue-violet emitting phosphor CaYA1O4:Ti^4+with enhanced emission by Ca^2+vacancies

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Journal of Rare Earths 2020年第3期38卷 227-233页

作者： Mao xia Yongli Zhang Mingh.i Li Yuan Zhong Simin Gu Nan zhou Zhi zhou College of Science Hunan Agricultural UniversityChangsha 410128China hunan Optical Agriculture Engineering Technology Research Center Changsha 410128China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Blue-violet light can not only enhance the total content of biomass and glucoside but also enrich the taste of the ***,it is meaningful to study the blue-violet luminescent materials for plant *** this study,titanium(iV)-activated CaYAlO4(CYAO) phosphors were synthesized by conventional hightemperature solid-state reaction.X-ray powder diffraction was employed to analyze the crystalstructure of *** is found that the doped Ti^4+ ions do not change obviously the crystal structure of *** 246 nm excitation,CaYAl1-xO4:xTi^4+phosphors exhibit broad blue-violet emission band peaking at 395 nm,which can be attributed to the charge transfer of Ti^4+-O^2-.Moreover,this phosphor exhibits strong thermal *** luminescence emission intensity at 150℃maintained about 91 mol% of its initial value at room ***,the electron transition process and concentration quenching mechanism of CaYAl1-xO4:xTi^4+are discussed in *** excellent luminescent properties indicate that CaYAl1-xO4:xTi^4+phosphor may have promising application in indoor plant cultivation.

关键词： Blue-violet-emitting Ca^2+ vacancies Phosphors Plant growth ligh.ing Ti^4+-activated

Safety lifetime analysis method for multi-mode time-dependent structural system

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Chinese Journal of Aeronautics 2022年第11期35卷 294-308页

作者： Yingshi hU Zhenzhou LU Ning WEi xia JiANG Changcong zhou School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

it is important to determine the safety lifetime of Multi-mode Time-Dependent Structural System(MTDSS). however, there is still a lack of corresponding analysis ***, this paper establishes MTDSS safety lifetime model firstly, and then proposes a Kriging surrogate model based method to estimate safety lifetime. The first step of proposed method is to construct the Kriging model of MTDSS performance function by using extremum learning function. By identifying possible extremum mode of MTDSS, the performance function of MTDSS can be equivalently transformed into the one of Single-mode Time-Dependent Structure(STDS).The second step is to use the Advanced First Failure instant Learning Function(AFFiLF) to train the Kriging model constructed in the first step, so that the convergent Kriging model can identify the possible First Failure instant(FFi) of STDS. Then safety lifetime can be searched quickly by dichotomy search. By using AFFiLF, the minimum instant that the state is not accurately identified by the current Kriging model is selected as the training point, which avoids the unnecessary calculation which may be introduced into the existing First Failure instant Learning Function(FFiLF).in addition, the Candidate Sample Pool(CSP) reduction strategy is also adopted. By adaptively deleting the random candidate sample points whose FFi have been accurately identified by the current Kriging model, the training efficiency is further improved. Three cases show that the proposed method is accurate and efficient.

关键词： Kriging Learning function Lifetime System reliability Time-dependent reliability analysis

Reliability study of super-ellipsoid DEM in representing the packing structure of blast furnace

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Particuology 2022年第11期70卷 72-81页

作者： Xiuhao xia Lianyong zhou huaqing Ma Changhua Xie Yongzhi Zhao institute of Process Equipment College of Energy EngineeringZhejiang UniversityHangzhou 310027China

in industrial blast furnaces(BFs),the investigations involving the flow behaviors of particles and the resultant burden structure are essential to optimize its operation stability and energy *** the advance of computing capability and mathematical model,the discrete element method(DEM)specialized in characterizing particle behavior has manifested its power in the investigation of *** the framework of DEM,many particle models have been developed,but which model is more suitable for simulating the particle behaviors of BFs remains a question because real particles in BFs have large shape and size *** these particle models,the super-ellipsoid model possesses the ability to change shape ***,the focus of this study is to investigate whether the super-ellipsoid model can meet the requirement of authenticity and accuracy in simulating the behaviors of particles with large shape and size *** answer this question,a simplified BF charging system composed of a hopper and a storage bin is *** charging process and the final packing structure are analyzed and compared between experiments and simulations with different shape *** results show that super-ellipsoid particles have prominent advantages over spherical particles in terms of representing the real BF particles,and it can more reasonably reproduce the flow behaviors and packing structure of experimental *** computation cost of super-ellipsoid particles is also acceptable for engineering ***,the micro-scale characteristics of packing structure is analyzed and the single-ring charging process in industry-scale BF using super-ellipsoid particles is conducted.

关键词： Blast furnace Discrete element method(DEM) Super-ellipsoid model Non-spherical particle Packing structure