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Traffic prediction enabled dynamic access points switching for energy saving in dense networks

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Digital Communications and Networks 2023年第4期9卷 1023-1031页

作者： yuchao Zhu Shaowei Wang School of Electronic Science and Engineering Nanjing UniversityNanjing210000China

To meet the ever-increasing traffic demand and enhance the coverage of cellular networks,network densification is one of the crucial paradigms of 5G and beyond mobile networks,which can improve system capacity by deploying a large number of Access Points(APs)in the service ***,since the energy consumption of APs generally accounts for a substantial part of the communication system,how to deal with the consequent energy issue is a challenging task for a mobile network with densely deployed *** this paper,we propose an intelligent AP switching on/off scheme to reduce the system energy consumption with the prerequisite of guaranteeing the quality of service,where the signaling overhead is also taken into consideration to ensure the stability of the ***,based on historical traffic data,a long short-term memory method is introduced to predict the future traffic distribution,by which we can roughly determine when the AP switching operation should be triggered;second,we present an efficient three-step AP selection strategy to determine which of the APs would be switched on or off;third,an AP switching scheme with a threshold is proposed to adjust the switching frequency so as to improve the stability of the *** results indicate that our proposed traffic forecasting method performs well in practical scenarios,where the normalized root mean square error is within 10%.Furthermore,the achieved energy-saving is more than 28% on average with a reasonable outage probability and switching frequency for an area served by 40 APs in a commercial mobile network.

关键词： Access points switching on/off Energy-saving Green network Long short-term memory Traffic prediction

Values of binary linear forms at prime arguments

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Frontiers of Mathematics in China 2015年第6期10卷 1449-1459页

作者： yuchao Wang Department of Mathematics Shanghai University Shanghai 200444 China

We investigate the exceptional set of real numbers not close to some value of a given binary linear form at prime arguments. Let λ1 and λ2 be positive real numbers such that λ1/λ2 is irrational and algebraic. For any （C, c） well-spaced sequence v and δ 〉 0, let E（v, X,δ ） denote the number of ν∈v with v ≤ X for which the inequality ｜λ1P1 ＋ λ2P2 - v｜〈 v-δ has no solution in primes P1,P2. It is shown that for any ε 〉 0, we have E（V, X, δ）〈〈 max（X3/5＋2δ＋ε, X1/3＋4/3δ＋ε）.

关键词： Circle method Diophantine inequality

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苏北不同林龄杨树人工林碳储量时空分配格局

水土保持研究 2025年第1期32卷 243-248页

作者：顾宇晨张茜安宇超王国兵南京林业大学生态与环境学院南方现代林业协同创新中心

[目的]探讨不同林龄对苏北杨树人工林生产力形成及林分碳储量地上、地下空间分配格局的影响及机理，为提高杨树人工林生态系统碳汇功能以及为杨树人工林经营和管理等提供科学依据。[方法]基于江苏省宿迁市泗洪林场，选取10个不同林龄分... 详细信息

[目的]探讨不同林龄对苏北杨树人工林生产力形成及林分碳储量地上、地下空间分配格局的影响及机理，为提高杨树人工林生态系统碳汇功能以及为杨树人工林经营和管理等提供科学依据。[方法]基于江苏省宿迁市泗洪林场，选取10个不同林龄分别为2,5,6,7,8,10,14,16,17,26 a生，林分密度为6 m×6 m的杨树人工林作为试验调查样地。分析了杨树人工林乔木层、草本层及土壤层碳储量净积累随林龄的变化规律及杨树人工林不同层次碳储量变化与土壤理化性质的相关关系。[结果]（1）乔木层碳储量在林分发展过程中呈现快速净积累特征，拟合其年平均积累速率、连年积累速率两条曲线，表明杨树人工林最佳轮伐期为15～20 a;（2）土壤有机碳在林分发展过程中呈现出缓慢的净积累，林下草本层碳储量随林分发展呈降低趋势；（3）杨树人工林土壤层和乔木层碳储量与土壤中SOC,TN,NO-3-N,N/P呈显著正相关，与AP,C/N,pH呈负相关。[结论]在杨树人工林生长过程中施N肥以及在土壤固碳水平最佳时期15～20 a进行轮作，有助于林分碳储量增加。

关键词：碳储量杨树人工林不同林龄苏北地区

Constrained LQ Problem with a Random Jump and Application to Portfolio Selection

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Chinese Annals of Mathematics,Series B 2018年第5期39卷 829-848页

作者： yuchao DONG Department of Mathematics Fudan University

This paper deals with a constrained stochastic linear-quadratic（LQ for short）optimal control problem where the control is constrained in a closed cone. The state process is governed by a controlled SDE with random coefficients. Moreover, there is a random jump of the state process. In mathematical finance, the random jump often represents the default of a counter party. Thanks to the Ito-Tanaka formula, optimal control and optimal value can be obtained by solutions of a system of backward stochastic differential equations（BSDEs for short）. The solvability of the BSDEs is obtained by solving a recursive system of BSDEs driven by the Brownian motions. The author also applies the result to the mean variance portfolio selection problem in which the stock price can be affected by the default of a counterparty.

关键词： Backward stochastic Riccati equation Default time Mean-varianceproblem

On the saturation number for singular cubic surfaces

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Science China Mathematics 2023年第12期66卷 2803-2818页

作者： yuchao Wang Weili Yao Department of Mathematics Shanghai UniversityShanghai 200444China

We investigate the distribution of rational points on singular cubic surfaces,whose coordinates have few prime *** key tools used are universal torors,the circle method and results on linear equations in primes.

关键词： circle method universal torsors cubic surfaces prime

Decreasing ruminal methane production through enhancing the sulfate reduction pathway

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Animal Nutrition 2022年第2期9卷 320-326页

作者： yuchao Zhao Guangyong Zhao State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural University100193 BeijingChina

Methane(CH4)production from ruminants accounts for 16%of the global greenhouse gas emissions and represents 2%to 12%of feed *** CH_(4) production from ruminants is of great importance for sustainable development of the ruminant industry.H_(2) is the primary substrate for CH_(4) production in the processes of ruminal *** reducing bacteria are able to compete with methanogens for H_(2) in the rumen,and consequently inhibit the *** the ruminal sulfate reducing pathway is an important approach to mitigate CH_(4) emissions in *** review summarized the effects of sulfate and elemental S on ruminal methanogenesis,and clarified the related mechanisms through the impacts of sulfate and elemental S on major ruminal sulfate reducing *** the activities of the major ruminal sulfate reducing bacteria including Desulfovibrio,Desulfohalobium and Sulfolobus through dietary sulfate addition,elemental S and dried distillers grains with solubles can effectively decrease the ruminal CH_(4) *** levels of dietary addition with different S sources for reducing the ruminal CH_(4) production,as well as maintaining the performance and health of ruminants,need to be investigated in the future.

关键词： Methane Rumen Sulfur Sulfate reduction pathway

Two-frequency mutual coherence function and its applications to pulse scattering by random rough surface

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Science China(Physics,Mechanics & Astronomy) 2008年第2期51卷 157-164页

作者： REN yuchao GUO LiXin School of Science Xidian UniversityXi’an 710071China

An analytic expression of the two-frequency mutual coherence function (MCF) was derived for a two-dimensional random rough surface. The scattered field was cal-culated by the Kirchhoff approximation, which is valid in the case that the radius of curvature of the surface is much larger than the incident wave length. The scatter-ing problem of narrowband pulse was investigated to simplify the analytic expres-sion of the two-frequency MCF. Numerical simulations show that the two-frequency MCF is greatly dependent on the root-mean-square (RMS) height, while less de-pendent on the correlation length. The analytic solutions were compared with the results of Monte Carlo simulation to assess the accuracy and computational efficiency.

关键词： mutual coherence function pulse scattering random rough surface

Single-cell biomagnifier for optical nanoscopes and nanotweezers

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Light(Science & Applications) 2019年第1期8卷 651-662页

作者： yuchao Li Xiaoshuai Liu Baojun Li Institute of Nanophotonics Jinan University511443 GuangzhouChina

Optical microscopes and optical tweezers,which were invented to image and manipulate microscale objects,have revolutionized cellular and molecular ***,the optical resolution is hampered by the diffraction limit;thus,optical microscopes and optical tweezers cannot be directly used to image and manipulate *** emerging plasmonic/photonic nanoscopes and nanotweezers can achieve nanometer resolution,but the high-index material structures will easily cause mechanical and photothermal damage to ***,we demonstrate subdiffraction-limit imaging and manipulation of nano-objects by a noninvasive device that was constructed by trapping a cell on a fiber *** trapped cell,acting as a biomagnifier,could magnify nanostructures with a resolution of 100 nm(λ/5.5)under white-light *** focus of the biomagnifier formed a nano-optical trap that allowed precise manipulation of an individual nanoparticle with a radius of 50 *** biomagnifier provides a high-precision tool for optical imaging,sensing,and assembly of bionanomaterials.

关键词： limit optical resolution

Memristive dynamics enabled neuromorphic computing systems

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Science China(Information Sciences) 2023年第10期66卷 5-19页

作者： Bonan YAN yuchao Yang Ru HUang Center for Brain Inspired Chips Institute for Artificial Intelligence Peking University Beijing Advanced Innovation Center for Integrated Circuits School of Integrated Circuits Peking University School of Electronic and Computer Engineering Peking University Center for Brain Inspired Intelligence Chinese Institute for Brain Research(CIBR)

The slowing down of transistor scaling and explosive growth for intelligence computing power emerge as the two driving factors for the study of novel devices and materials to pursue highly-efficient computing systems. Memristors, incorporating rich intrinsic dynamics, are a promising candidate for constructing efficient and scalable bio-inspired computing systems. In this progress report, we review the latest advances in novel types of memristors as well as their applications in implementing neuromorphic computing systems. This paper not only covers the memristive dynamics-enabled bionic computing systems but also discusses the memristive sensory systems that integrate sensing and computing. Eventually, device-circuit co-optimization methods are given to emphasize the trend of cross-layer co-design in this fast-evolving *** innovation in memristor devices mainly focuses on specialized computing hardware and yields superior computing and sensing efficiency. At last, we offer our insight into the trend of state-of-the-art research in memristive materials, devices, circuits, and systems.

关键词： memrsitor memristive dynamics artificial synapse artificial neuron neuromorphic computing