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Gloo+:利用在网计算技术加速分布式深度学习训练

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计算机工程与科学 2024年第1期46卷 28-36页

作者：黄泽彪董德尊齐星云国防科技大学计算机学院湖南长沙410073

在分布式深度学习训练中,聚合通信是主要的通信方式。在聚合通信优化的研究中,有软件层面的优化和硬件层面的优化。sharp是Mellanox提出来的一种聚合通信网络卸载协议,是针对聚合通信在硬件上的优化,其将聚合操作卸载到网络中的交换机,... 详细信息

在分布式深度学习训练中,聚合通信是主要的通信方式。在聚合通信优化的研究中,有软件层面的优化和硬件层面的优化。sharp是Mellanox提出来的一种聚合通信网络卸载协议,是针对聚合通信在硬件上的优化,其将聚合操作卸载到网络中的交换机,进而缩短了聚合通信时间。在Gloo的基础上集成了sharp技术,设计并实现了一个能够利用在网计算技术来加速分布式深度学习训练的聚合通信库——Gloo+。评估并比较了Gloo+、Gloo以及MPI中聚合操作的性能,并将Gloo+应用于分布式深度学习训练中,以此来检验其实战能力。对Gloo+的实验评估结果显示,在基准测试时,在消息大小较小的情况下,Gloo+相对于Gloo的加速比最高能达到100以上;相比于以太网模式下的MPI,其加速比最高也能达到50以上;相比于IB网模式下的MPI,其加速比在10以内。在分布式深度学习训练的实际应用中,Gloo+相比于Gloo加速比最高能达到1.1,相比于以太网模式下的MPI加速比最高有1.3,相比于IB网模式下的MPI加速比最高有0.5。

关键词：分布式深度学习聚合通信在网计算 Gloo sharp

Insights into the phenomenon of an explosive growth and sharp decline in haze:A case study in Beijing

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Journal of Environmental Sciences 2019年第10期31卷 122-132页

作者： Wenguang Li Xingang Liu Yuanhang Zhang Qinwen Tan Miao Feng Mengdi Song Lirong Hui Yu Qu Junling An Haokai Gao State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing 100875 China State Key Joint Laboratory of Environment Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing 100871 China Chengdu Academy of Environmental Sciences Chengdu 610072 China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Environmental monitoring station of Tianjin Port Free Trade Zone Tianjin 300308 China

A severe haze episode occurred in winter in the North China Plain(NCP),and the phenomenon of an explosive growth and sharp decline in PM2.5(particulate matter with an aerodynamic diameter equal to or less than 2.5μm)concentration was observed.To study the systematic causes for this phenomenon,comprehensive observations were conducted in Beijing from November 26 to December 2,2015;during this period,meteorological parameters,LIDAR data,and the chemical compositions of aerosols were determined.The haze episode was characterized by rapidly varying PM2.5 concentration,and the highest PM2.5 concentration reached 667μg/m3.During the haze episode,the NCP was dominated by a weak high-pressure system and continuously low PBL(planetary boundary layer)heights,which are unfavorable conditions for the diffusion of pollutants.The large increases in the concentrations of SNA(SO42-,NO3-and NH4+)during the haze implied that the formation of SNA was the largest contribution.Water vapor also played a vital role in the formation of haze by promoting the chemical transformation of secondary pollutants,which led to higher PM2.5 concentrations.The spatial distributions of PM2.5 in Beijing at different times and the backward trajectories of the air masses also indicated that pollutants from surrounding provinces in particular,contributed to the higher PM2.5concentration.

关键词： Haze episodes Explosive growth sharp decline Beijing

sharp ESTIMATES OF QUASI-CONVEX MAPPINGS OF TYPE B AND ORDER α

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Acta Mathematica Scientia 2019年第5期39卷 1265-1276页

作者：刘名生吴芬杨燕 School of Mathematical Sciences South China Normal University Guangzhou 510631 China School of Mathematics(Zhuhai) Sun Yat-Sen University Zhuhai 519080 China

In this paper, we first establish several sharp inequalities of homogeneous expansion for biholomorphic quasi-convex mappings of type B and order α on the unit ball E in a complex Banach space X by applying the method and technique of complex analysis. Then, as the application of these sharp inequalities, we derive the sharp estimate of third homogeneous expansions for the above mappings defined on the unit polydisk U^n in C^n.

关键词： quasi-convex mappings of type B and order α inequalities of homogeneous expansions the sharp estimate of third homogeneous expansions

How do Normal Traders and sharp Traders Make Profits in the Chinese Security Market?

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Journal of Systems Science and Systems Engineering 2020年第2期29卷 203-234页

作者： Mingyang Zhang Juliang Zhang TCECheng Guowei Hua Department of Management Science and Engineering School of Economics and ManagementBeijing Forestry UniversityBeijing 100083China Department of Management Science and Engineering School of Economics and ManagementBeijing Jiaotong UniversityBeijing 100044China Department of Logistics and Maritime Studies The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SAR

In this paper,we consider the strategic interaction between the normal and sharp traders in a dynamic limit-order security market and its impact on the Chinese security market at different market volatility levels.We find that when the proportion of sharp traders is less than a threshold in an orderdriven market,the sharp traders who submit limit orders will get more returns than the normal traders.The participation of sharp traders in the market can increase the total social welfare of all the traders.In addition,we show that:(1)when the market volatility level is generally low,the short-term sharp traders benefit from larger volatility;(2)when the market volatility level is generally high,the insider/cheating sharp traders with high-frequent trading rather than the short-term sharp traders benefit from extreme high volatility;(3)when the market volatility level is moderate,the sharp traders can increase market liquidity.

关键词： sharp trader order-driven market limit-order strategic interaction

A unified theory for sharp dissolution front propagation inchemical dissolution of fluid-saturated porous rocks

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Science China(Technological Sciences) 2019年第1期62卷 163-174页

作者： ZHAO ChongBin HOBBS Bruce ORD Alison Computational Geosciences Research Centre Central South University School of Earth and Environment The University of Western Australia

This paper presents a unified theory to deal with when, why and how a sharp acidization dissolution front(ADF), which is represented by the porosity distribution curve, can take place in an acidization dissolution system composed of fluid-saturated porous rocks. The theory contains the following main points:(1) A reaction rate of infinity alone can lead to a sharp ADF of the Stefan-type in the acidization dissolution system. This sharp front is unstable when permeability in the downstream region is smaller than that in the upstream region.(2) For a finite reaction rate, when the acid dissolution capacity number approaches zero,the ADF can have a sharp profile of the Stefan-type either on a much smaller time scale or on a much larger time scale than the dissolution time scale. In the former case, the ADF may become unstable on a much larger time scale than the transport time scale, while in the latter case, it may become unstable if the growth rate of a small perturbation is greater than zero.(3) On the dissolution time scale, even if both the reaction rate is finite and the acid dissolution capacity number approaches zero, the profile of an ADF may not be sharp because it is in a transient state. In this case, not only can an ADF change its profile with time, but also its morphology can grow if the growth rate of a small perturbation is greater than zero. Due to the involvement of both the change rate and the growth rate of the ADF profile, it is necessary to conduct a transient linear stability analysis for determining whether or not a time-dependent ADF is stable in the acidization dissolution system.

关键词： sharp dissolution front stationary/steady state transient state acid dissolution capacity acidization dissolution porous rocks

sharp Fano resonance in 2D photonic crystal and the applications

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Optoelectronics Letters 2020年第5期16卷 349-354页

作者：陈兵陈德媛夏雨张岩李梦凡 Nangjing University of Posts and Telecommunications Nanjing 210009China

Fano resonance is realized theoretically in a photonic crystal.The structure is composed of a cavity side coupled to a partially transmitting waveguide.By optimizing the structure parameters,asymmetric sharp Fano resonance transmittance spectrum is achieved with quality factor of 2213,extinction ratio of 57 dB and peak loss of 0.2 dB.The sharp spectrum can be used in sensor applications.Such as pressure sensor,the pressure sensitivity is about 9.15 nm/GPa.and for refractive index sensing application,the sensitivity is about 800 nm/RIU,and the maximum of figure of merit can reach 1000.Besides,this sharp Fano resonance based on photonic crystal has potential applications in optical switches,filters etc.And it can be integrated into optical communications and optical integration circuits.

关键词： resonance sharp crystal

Research of Power Take-off System for “sharp Eagle Ⅱ” Wave Energy Converter

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China Ocean Engineering 2019年第5期33卷 618-627页

作者： YE Yin WANG Kun-lin YOU Ya-ge SHENG Song-wei Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 510640 China Key Laboratory of Renewable Energy Chinese Academy of Sciences Guangzhou 510640 China Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640 China

The " sharp Eagle” device is a wave energy converter of a hinged double floating body. The wave-absorbing floating body hinges on the semi-submerged floating body structure. Under the action of wave, the wave-absorbing floating body rotates around the hinge point, and the wave energy can be converted into kinetic energy. In this paper, the power take-off system of " sharp Eagle Ⅱ” wave energy converter (the second generation of " sharp Eagle”) was studied, which adopts the hydraulic type power take-off system. The 0-1 power generation mode was applied in this system to make the " sharp Eagle Ⅱ” operate under various wave conditions. The principle of power generation was introduced in detail, and the power take-off system was simulated. Three groups of different movement period inputs were used to simulate three kinds of wave conditions, and the simulation results were obtained under three different working conditions. In addition, the prototype of " sharp Eagle Ⅱ” wave energy converter was tested on land and in real sea conditions. The experimental data have been collected, and the experimental data and simulation results were compared and validated. This work has laid a foundation for the design and application of the following " sharp Eagle” series of devices.

关键词： sharp Eagle Wave Energy Converter power take-off power generation mode hydraulic system

sharp L^p decay of oscillatory integral operators with certain homogeneous polynomial phases in several variables

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Science China Mathematics 2019年第4期62卷 649-662页

作者： Shaozhen Xu Dunyan Yan School of Mathematical Sciences University of Chinese Academy of Sciences

In this paper, we obtain the L^p decay of oscillatory integral operators T_λ with certain homogeneous polynomial phase functions of degree d in(n + n)-dimensions; we require that d > 2 n. If d/(d-n) sharp and the decay rate is related to the Newton distance. For p = d/n or d/(d-n), we obtain the almost sharp decay, where "almost" means that the decay contains a log(λ) term. For otherwise, the L^p decay of T_λ is also obtained but not sharp. Finally, we provide a counterexample to show that d/(d-n) p d/n is not necessary to guarantee the sharp decay.

关键词： oscillatory integral operators sharp L^p decay several variables Newton distance

sharp Threshold of Global Existence for a Nonlocal Nonlinear Schrdinger System in R^(3)

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Chinese Annals of Mathematics,Series B 2019年第1期40卷 131-160页

作者： Zaihui GAN Xin JIANG Jing LI Center for Applied Mathematics Tianjin University School of Preparatory Education Xinjiang Normal University

In this paper, the authors investigate the sharp threshold of a three-dimensional nonlocal nonlinear Schr¨odinger system. It is a coupled system which provides the mathematical modeling of the spontaneous generation of a magnetic field in a cold plasma under the subsonic limit. The main difficulty of the proof lies in exploring the inner structure of the system due to the fact that the nonlocal effect may bring some hinderance for establishing the conservation quantities of the mass and of the energy, constructing the corresponding variational structure, and deriving the key estimates to gain the expected result. To overcome this, the authors must establish local well-posedness theory, and set up suitable variational structure depending crucially on the inner structure of the system under study, which leads to define proper functionals and a constrained variational problem. By building up two invariant manifolds and then making a priori estimates for these nonlocal terms, the authors figure out a sharp threshold of global existence for the system under consideration.

关键词： Nonlocal nonlinear Schrödinger system sharp threshold Blow-up Global existence