The intensification of a low-level jet off the Somali coast, as observed through GOES (I-O) satellite during Indian summer monsoon 1979 has been studied. Excitation of Low-level cross-equatorial flow in the western In...The intensification of a low-level jet off the Somali coast, as observed through GOES (I-O) satellite during Indian summer monsoon 1979 has been studied. Excitation of Low-level cross-equatorial flow in the western Indian ocean results from an interaction between extratropical perturbations moving eastward across the South African-Malgassy region of the Southern Hemisphere. This excitation occurs 2-3 days after the first appearance of a northward propagation cold front across the South African-Malgassy region. Inten-sification of cross-equatorial flow is followed by an increase in rainfall activity along the west coast of India after 3-4 days. The study reveals that this association can be used to forecast an increase in rainfall activity along the west coast of India 5-7 days in advance.展开更多
The first task in ensuring a reduction in CO2 emissions is to quantitatively measure the factors and their effect size on increasing CO2 emissions due to fossil fuel consumption. An extension of the buying and import-...The first task in ensuring a reduction in CO2 emissions is to quantitatively measure the factors and their effect size on increasing CO2 emissions due to fossil fuel consumption. An extension of the buying and import-noncompetition economy-energy-CO2 emission input-output model was designed to analyze CO2 emission increases for Beijing from 1997-2007. The increase in CO2 emissions because of energy consumption was broken down into nine kinds of effects including the change in energy consumption intensity and structure, and economic scale expansion. We found that the effect of economic scale expansion such as consumption investment, export and selling were the main factors increasing CO2 emissions. The effect of the change in energy consumption intensity was the dominant factor reducing CO2 emissions. CO2 emissions increased rapidly from 2002. The ifrst increase in carbon emissions was related to the service industry, adjustment in industrial structure and the priority given to tertiary industries. High energy consumption manufacturing was the industrial branch driving CO2 emissions; the main industry driving CO2 emission reductions was the energy industry. The new round of industrialization with ‘high carbon’ features meant that CO2 emissions increased rapidly from 2002-2007. The quantity and direction of the nine focal effects varied across industries and different industrial sectors.展开更多
随着大语言模型(large language models,LLMs)(以下简称“大模型”)参数规模的持续增长,微调百亿级参数大模型对计算和存储资源提出了极高要求。传统分布式训练方案通常依赖大量高端GPU和高速互联网络,训练成本极为昂贵。现有单GPU训练...随着大语言模型(large language models,LLMs)(以下简称“大模型”)参数规模的持续增长,微调百亿级参数大模型对计算和存储资源提出了极高要求。传统分布式训练方案通常依赖大量高端GPU和高速互联网络,训练成本极为昂贵。现有单GPU训练方案虽通过张量卸载缓解显存压力,但仍然面临I/O传输效率低和设备利用率不足等问题。传统内核态I/O操作在大规模张量迁移中引入频繁的系统调用和上下文切换,成为制约性能的关键瓶颈;同时,优化器计算无法充分发挥多核CPU的并行能力,难以实现与GPU计算的有效重叠,进一步限制了系统性能。针对上述问题,提出了一种面向大模型训练的异构内存卸载与I/O优化方案HiTrain。首先构建了基于存储性能开发工具包(storage performance development kit,SPDK)的高性能张量存储模块,通过在用户态管理张量数据,避免了内核I/O栈开销,从而提高张量卸载的并发性与吞吐率;其次,设计并实现了基于异步优化器的存储-计算流水线调度模块,通过对优化器的执行进行优化重排来减少GPU等待时间,提高整体训练效率。实验结果表明,在配备单张GPU和非易失性存储器快速固态硬盘(non-volatile memory express solid state drive,NVMe SSD)的服务器上,所提出的方案能够充分利用系统中的存算资源,使得模型训练过程中张量卸载与加载效率提升32.7%,整体训练吞吐提升至现有方案的1.49倍,为低成本大模型训练提供了切实可行的技术路径。展开更多
文摘The intensification of a low-level jet off the Somali coast, as observed through GOES (I-O) satellite during Indian summer monsoon 1979 has been studied. Excitation of Low-level cross-equatorial flow in the western Indian ocean results from an interaction between extratropical perturbations moving eastward across the South African-Malgassy region of the Southern Hemisphere. This excitation occurs 2-3 days after the first appearance of a northward propagation cold front across the South African-Malgassy region. Inten-sification of cross-equatorial flow is followed by an increase in rainfall activity along the west coast of India after 3-4 days. The study reveals that this association can be used to forecast an increase in rainfall activity along the west coast of India 5-7 days in advance.
基金the National Twelfth-Five Year Science and Technology Support Program(2011BAJ07B03-06)
文摘The first task in ensuring a reduction in CO2 emissions is to quantitatively measure the factors and their effect size on increasing CO2 emissions due to fossil fuel consumption. An extension of the buying and import-noncompetition economy-energy-CO2 emission input-output model was designed to analyze CO2 emission increases for Beijing from 1997-2007. The increase in CO2 emissions because of energy consumption was broken down into nine kinds of effects including the change in energy consumption intensity and structure, and economic scale expansion. We found that the effect of economic scale expansion such as consumption investment, export and selling were the main factors increasing CO2 emissions. The effect of the change in energy consumption intensity was the dominant factor reducing CO2 emissions. CO2 emissions increased rapidly from 2002. The ifrst increase in carbon emissions was related to the service industry, adjustment in industrial structure and the priority given to tertiary industries. High energy consumption manufacturing was the industrial branch driving CO2 emissions; the main industry driving CO2 emission reductions was the energy industry. The new round of industrialization with ‘high carbon’ features meant that CO2 emissions increased rapidly from 2002-2007. The quantity and direction of the nine focal effects varied across industries and different industrial sectors.
文摘随着大语言模型(large language models,LLMs)(以下简称“大模型”)参数规模的持续增长,微调百亿级参数大模型对计算和存储资源提出了极高要求。传统分布式训练方案通常依赖大量高端GPU和高速互联网络,训练成本极为昂贵。现有单GPU训练方案虽通过张量卸载缓解显存压力,但仍然面临I/O传输效率低和设备利用率不足等问题。传统内核态I/O操作在大规模张量迁移中引入频繁的系统调用和上下文切换,成为制约性能的关键瓶颈;同时,优化器计算无法充分发挥多核CPU的并行能力,难以实现与GPU计算的有效重叠,进一步限制了系统性能。针对上述问题,提出了一种面向大模型训练的异构内存卸载与I/O优化方案HiTrain。首先构建了基于存储性能开发工具包(storage performance development kit,SPDK)的高性能张量存储模块,通过在用户态管理张量数据,避免了内核I/O栈开销,从而提高张量卸载的并发性与吞吐率;其次,设计并实现了基于异步优化器的存储-计算流水线调度模块,通过对优化器的执行进行优化重排来减少GPU等待时间,提高整体训练效率。实验结果表明,在配备单张GPU和非易失性存储器快速固态硬盘(non-volatile memory express solid state drive,NVMe SSD)的服务器上,所提出的方案能够充分利用系统中的存算资源,使得模型训练过程中张量卸载与加载效率提升32.7%,整体训练吞吐提升至现有方案的1.49倍,为低成本大模型训练提供了切实可行的技术路径。
