检索结果-南通市图书馆

The Alternating Group Explicit Iterative Method for the Regularized Long-Wave Equation

在线全文

学校读者我要写书评

暂无评论

Journal of Applied Mathematics and Physics 2024年第1期12卷 52-59页

作者： Anqi Xie Xiaojia Ye Guanyu Xue School of Mathematics and Information Sciences Yantai University Yantai China

An Alternating Group Explicit (AGE) iterative method with intrinsic parallelism is constructed based on an implicit scheme for the Regularized Long-Wave (RLW) equation. The method can be used for the iteration solution of a general tridiagonal system of equations with diagonal dominance. It is not only easy to implement, but also can directly carry out parallel computation. Convergence results are obtained by analysing the linear system. Numerical experiments show that the theory is accurate and the scheme is valid and reliable.

关键词： RLW Equation AGE Iterative Method parallelism Convergence

parallelism and Optimization of Numerical Ocean Forecasting Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2016年第5期15卷 783-788页

作者： XU Jianliang PANG Renbo TENG Junhua LIANG Hongtao YANG Dandan College of Information Science and Engineering Ocean University of China Department of Computer and Network National Marine Environmental Forecasting Center Division of Information System National Marine Environmental Forecasting Center

According to the characteristics of Chinese marginal seas, the Marginal Sea Model of China(MSMC) has been developed independently in China. Because the model requires long simulation time, as a routine forecasting model, the parallelism of MSMC becomes necessary to be introduced to improve the performance of it. However, some methods used in MSMC, such as Successive Over Relaxation(SOR) algorithm, are not suitable for parallelism. In this paper, methods are developedto solve the parallel problem of the SOR algorithm following the steps as below. First, based on a 3D computing grid system, an automatic data partition method is implemented to dynamically divide the computing grid according to computing resources. Next, based on the characteristics of the numerical forecasting model, a parallel method is designed to solve the parallel problem of the SOR algorithm. Lastly, a communication optimization method is provided to avoid the cost of communication. In the communication optimization method, the non-blocking communication of Message Passing Interface(MPI) is used to implement the parallelism of MSMC with complex physical equations, and the process of communication is overlapped with the computations for improving the performance of parallel MSMC. The experiments show that the parallel MSMC runs 97.2 times faster than the serial MSMC, and root mean square error between the parallel MSMC and the serial MSMC is less than 0.01 for a 30-day simulation(172800 time steps), which meets the requirements of timeliness and accuracy for numerical ocean forecasting products.

关键词： ocean numerical model parallelism optimization

Hound:a parallel image distribution system for cluster based on Docker

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2023年第4期34卷 955-965页

作者： LIU Zijie LI Junjiang CHEN Can ZHANG Dengyin School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Key Laboratory of Broadband Wireless Communication and Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China College of Telecommunications&Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China

Current applications,consisting of multiple replicas,are packaged into lightweight containers with their execution dependencies.Considering the dominant impact of distribution efficiency of gigantic images on container startup(e.g.,distributed deep learning application),the image“warm-up”technique which prefetches images of these replicas to destination nodes in the cluster is proposed.However,the current image“warm-up”technique solely focuses on identical image distribution,which fails to take effect when distributing different images to destination nodes.To address this problem,this paper proposes Hound,a simple but efficient cluster image distribution system based on Docker.To support diverse image distribution requests of cluster nodes,Hound additionally adopts node-level parallelism(i.e.,downloading images to destination nodes in parallel)to further improve the efficiency of image distribution.The experimental results demonstrate Hound outperforms Docker,kubernetes container runtime interface(CRI-O),and Docker-compose in terms of image distribution performance when cluster nodes request different images.Moreover,the high scalability of Hound is evaluated in the scenario of ten nodes.

关键词： container image image distribution parallelism containerization

VBMq： pursuit baremetal performance by embracing block I/O parallelism in virtualization

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2018年第5期12卷 873-886页

作者： Diming ZHANG Fei XUE Hao HUANG Shaodi YOU Faculty of Computer Science and Technology Nanjing University Nanjing 210023 China College of Computer Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China College of Engineering and Computer Science Australian National University Canberra 2600 Australia Data61-CSIRO Australian National University Canberra 2600 Australia

Barely acceptable block I/O performance prevents virtualization from being widely used in the HighPerformance Computing field. Although the virtio paravirtual framework brings great I/O performance improvement, there is a sharp performance degradation when accessing high-performance NAND-flash-based devices in the virtual machine due to their data parallel design. The primary cause of this fact is the deficiency of block I/O parallelism in hypervisor, such as KVM and Xen. In this paper, we propose a novel design of block I/O layer for virtualization, named VBMq. VBMq is based on virtio paravirtual I/O model, aiming to solve the block I/O parallelism issue in virtualization. It uses multiple dedicated I/O threads to handle I/O requests in parallel. In the meanwhile, we use polling mechanism to alleviate overheads caused by the frequent context switches of the VM＇s notification to and from its hypervisor. Each dedicated I/O thread is assigned to a non-ovedapping core to improve performance by avoiding unnecessary scheduling. In addition, we configure CPU affinity to optimize I/O completion for each request. The CPU affinity setting is very helpful to reduce CPU cache miss rate and increase CPU efficiency. The prototype system is based on Linux 4.1 kernel and QEMU 2.3.1. Our measurements show that the proposed method scales graciously in the multi-core environment, and provides performance which is 39.6x better than the baseline at most, and approaches bare-metal performance.

关键词： high-performance parallelism paravirtual I/O

General difference schemes with intrinsic parallelism for nonlinear parabolic systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 1997年第4期40卷 357-365页

作者：周毓麟袁光伟 Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China

The boundary value problem for nonlinear parabolic system is solved by the finite difference method with intrinsic parallelism. The existence of the discrete vector solution for the general finite difference schemes with intrinsic parallelism is proved by the fixed-point technique in finite-dimensional Euclidean space. The convergence and stability theorems of the discrete vector solutions of the nonlinear difference system with intrinsic parallelism are proved. The limitation vector function is just the unique generalized solution of the original problem for the parabolic system.

关键词： difference scheme intrinsic parallelism nonlinear parabolic system convergence stability.

PASS: a simple, efficient parallelism-aware solid state drive I/O scheduler

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第5期15卷 321-336页

作者： Hong-yan LI Nai-xue XIONG Ping HUANG Chao GUI Wuhan National Laboratory for Optoelectronics School of Computer Science and TechnologyHuazhong University of Science and Technology School of Information Management Hubei University of Economics School of Computer Science Colorado Technical University Colorado Spring

Emerging non-volatile memory technologies,especially flash-based solid state drives(SSDs),have increasingly been adopted in the storage stack.They provide numerous advantages over traditional mechanically rotating hard disk drives(HDDs)and have a tendency to replace HDDs.Due to the long existence of HDDs as primary building blocks for storage systems,however,much of the system software has been specially designed for HDD and may not be optimal for non-volatile memory media.Therefore,in order to realistically leverage its superior raw performance to the maximum,the existing upper layer software has to be re-evaluated or re-designed.To this end,in this paper,we propose PASS,an optimized I/O scheduler at the Linux block layer to accommodate the changing trend of underlying storage devices toward flash-based SSDs.PASS takes the rich internal parallelism in SSDs into account when dispatching requests to the device driver in order to achieve high performance.Specifically,it partitions the logical storage space into fixed-size regions(preferably the component package sizes)as scheduling units.These scheduling units are serviced in a round-robin manner and for every chance that the chosen dispatching unit issues only a batch of either read or write requests to suppress the excessive mutual interference.Additionally,the requests are sorted according to their visiting addresses while waiting in the dispatching queues to exploit high sequential performance of SSD.The experimental results with a variety of workloads have shown that PASS outperforms the four Linux off-the-shelf I/O schedulers by a degree of 3%up to41%,while at the same time it improves the lifetime significantly,due to reducing the internal write amplification.

关键词： Solid state drive(SSD) I/O scheduler parallelism

Difference schemes with intrinsic parallelism for quasi-linear parabolic systems

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 1997年第3期40卷 270-278页

作者：周毓麟 Laboratory of Computational Physics Center of Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing 100088 China

The boundary value problem for quasi-linear parabolic system is solved by the finite difference method with intrinsic parallelism The existence and uniqueness and convergence theorems of the discrete vector solu tions of the nonlinear difference system with intrinsic parallelism are proved The limiting vector function is just the unique generalized solution of the original problem for the parabolic

关键词： difference scheme intrinsic parallelism quasi-linear parabolic system.

Studies of the linearity of the readout module assembling using the eXTP-GPD chips

在线全文

学校读者我要写书评

暂无评论

辐射探测技术与方法(英文) 2023年第2期7卷 255-262页

作者： Jiechen Jiang Liang Sun Yang Jiao Weichun Jiang Yupeng Xu Huilin He Xiaohua Liu Yuanyuan Du Sheng Yang Zefang Dong Xiaojing Liu Boyu Dai Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China Key Laboratory of Particle Astrophysics Chinese Academy of SciencesBeijing100049China University of Chinese Academy of Sciences Beijing100049China

Background The Gas Pixel Detector(GPD)is a key part of the Polarimetry Focusing Array(PFA)sub-system onboard the enhance X-ray Timing and Polarimetry mission(eXTP).The GPD can accurately provide the polarized angle and degree for incoming soft X-rays(requirements of minimum detectable polarizationparallelism between the top surface of an ASIC chip and the bottom surface of a Gas Electron Multiplier(GEM)foil can have impact on the distribution of electric field within transfer region and reconstruction of photoelectric trajectories,resulting in deterioration of the GPD sensitivity.This study quantifies the influence and gives a reasonable expectation of the parallelism.Methods A simulation framework of the GPD is constructed to quantify the influence on the GPD performance and values of the parallelism are measured by a gauge with a position resolution of o.1μm.Results:The difference of degree of modulation is less than 1% comparing the parallelism with a value of 20μm to a value of 0μm in response to both polarized and unpolarized X-rays.Meanwhile,the value of parallelism can reach 6.9±3.4μm(0.0176°±0.0087°)by testing and verifying.Conclusions The impact on the GPD performance can be less than 1%as the parallelism with an order of 20μm,and we also give a reasonable measuring method and verify the controllability and feasibility of the parallelism with an order of 20μm for pasting the ASIC chip on the surface of a ceramic package.

关键词： parallelism Gas pixel detectors Gaseous detector simulation Measurements

A Study of parallelism in English Speeches

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Literature and Art Studies 2023年第9期13卷 692-698页

作者： NI Xiu-jing ZHANG Shun-sheng University of Shanghai for Science and Technology Shanghai200093 China

Every public speaker prepares his or her public speech meticulously.Witty remarks emerge in an endless stream,and demonstrate the rhetoric beauty of English to a great extent.Almost every speaker employs parallelism in his or her public speeches.The present paper is intended to study the concept,the classification and the significance of parallelism in English.

关键词： speeches parallelism concept classification significance