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Labeled yon Neumann Architecture for Software-Defined Cloud

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Journal of Computer Science & Technology 2017年第2期32卷 219-223页

作者： Yun-Gang Bao Sa Wang, member, ccf State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

As cloud computing is moving forward rapidly, cloud providers have been encountering great challenges： long tail latency, low utilization, and high interference. They intend to co-locate multiple workloads on a single server to improve the resource utilization. But the co-located applications suffer from severe performance interference and long tail latency, which lead to unpredictable user experience. To meet these challenges, software-defined cloud has been proposed to facilitate tighter coordination among application, operating system and hardware. Users＇ quality of service （QoS） requirements could be propagated all the way down to the hardware with differential management mechanisms. However, there is little hardware support to maintain and guarantee users＇ QoS requirements. To this end, this paper proposes Labeled von Neumann Architecture （LvNA）, which introduces a labelling mechanism to convey more software＇s semantic information such as QoS and security to the underlying hardware. LvNA is able to correlate labels with various entities, e.g., virtual machine, process and thread, and propagate labels in the whole machine and program differentiated services based on rules. We consider LvNA to be a fundamental hardware support to the software-defined cloud.

关键词： software-defined cloud von Neumann architecture tail latency performance interference

Global-to-Local Approach to Rigorously Developing Distributed System with Exception Handling

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Journal of Computer Science & Technology 2009年第2期24卷 238-249页

作者：蔡超裘宗燕 Senior member, member, ccf, IEEE 杨红丽赵翔鹏 LMAM and Department of Informatics School of Mathematical Science Peking University Beijing 100871 China College of Computer Sciences Beijing University of Technology Beijing 100124 China

Cooperative distributed system covers a wide range of applications such as the systems for industrial controlling and business-to-business trading, which are usually safety-critical. Coordinated exception handling （CEH） refers to exception handling in the cooperative distributed systems, where exceptions raised on a peer should be dealt with by all relevant peers in a consistent manner. Some CEH algorithms have been proposed. A crucial problem in using these algorithms is how to develop the peers which are guaranteed coherent in both normal execution and exceptional execution. Straightforward testing or model checking is very expensive. In this paper, we propose an effective way to rigorously develop the systems with correct CEH behavior. Firstly, we formalize the CEH algorithm by proposing a Peer Process Language to precisely describe the distributed systems and their operational semantics. Then we dig out a set of syntactic conditions, and prove its sufficiency for system coherence. Finally~ we propose a global-to-local approach, including a language describing the distributed systems from a global perspective and a projection algorithm, for developing the systems. Given a well-formed global description, a set of peers can be generated automatically. We prove the system composed of these peers satisfies the conditions, that is, it is always coherent and correct for CEH.

关键词： distributed system exception handling fault tolerant formal methods

CCNoC:Cache-Coherent Network on Chip for Chip Multiprocessors

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Journal of Computer Science & Technology 2010年第2期25卷 257-266页

作者：王惊雷薛一波 member, ccf, IEEE 王海霞李崇民汪东升 Senior member,ccf Department of Computer Science and Technology Tsinghua University Beijing 100084 China Tsinghua National Laboratory of Information Science and Technology Beijing 100084 China

As the number of cores in chip multiprocessors （CMPs） increases, cache coherence protocol has become a key issue in integration of chip multiprocessors. Supporting cache coherence protocol in large chip multiprocessors still faces three hurdles： design complexity, performance and scalability. This paper proposes Cache Coherent Network on Chip （CCNoC）, a scheme that decouples cache coherency maintenance from processors and shared L2 caches and implements it completely in network on chip to free up processors and shared L2 caches from the chore of maintaining coherency, thereby reduces design complexity of CMPs. In this way, CCNoC also improves the performance of cache coherence protocol through reducing directory access latency and enhances scalability by avoiding massive directories overhead in shared L2 caches. In CCNoC, coherence state caches and active directory caches are implemented in the network interface components of network on chip to maintain cache coherence states for blocks in L1 caches and manage directory information for recently accessed blocks in L2 caches respectively. CCNoC provides a scalable CMP framework to tackle cache coherency which is the foundation of CMP. This paper evaluates the performance of CCNoC. Experimental results show that for a 16-core system, CCNoC improves performance by 3% on average over the conventional chip multiprocessor and by 10% at best, while reduces storage overhead by 1.8% and saves directory storage by 88%, showing good scalability.

关键词： chip multiprocessor network on chip cache coherence protocol

A Novel Spatial Pooling Strategy for Image Quality Assessment

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Journal of Computer Science & Technology 2016年第2期31卷 225-234页

作者： Qiaohong Li Yu-Ming Fang member, ccf Jing-Tao Xu School of Computer Engineering Nanyang Technological University Singapore 639798 Singapore School of Information Technology Jiangxi University of Finance and Economics Nanchang 330013 China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100086 China

A variety of existing image quality assessment （IQA） metrics share a similar two-stage framework： at the first stage, a quality map is constructed by comparison between local regions of reference and distorted images; at the second stage, the spatial pooling is adopted to obtain overall quality score. In this work, we propose a novel spatial pooling strategy for image quality assessment through statistical analysis of the quality map. Our in-depth analysis indicates that the overall image quality is sensitive to the quality distribution. Based on the analysis, the quality histogram and statistical descriptors extracted from the quality map are used as input to the support vector regression to obtain the final objective quality score. Experimental results on three large public IQA databases have demonstrated that the proposed spatial pooling strategy can greatly improve the quality prediction performance of the original IQA metrics in terms of correlation with human subjective ratings.

关键词： image quality assessment spatial pooling statistical pooling support vector regression structural similarity

Providing Virtual Cloud for Special Purposes on Demand in JointCloud Computing Environment

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Journal of Computer Science & Technology 2017年第2期32卷 211-218页

作者： Dong-Gang Cao member, ccf, IEEE, Bo An Pei-Chang Shi Huai-Min Wang Key Laboratory of High Confidence Software Technologies (Peking University) Ministry of Education Beijing 100871 China National Key Laboratory for Parallel and Distributed Processing National University of Defense and Technology Changsha 410073 China

Cloud computing has been widely adopted by enterprises because of its on-demand and elastic resource usage paradigm. Currently most cloud applications are running on one single cloud. However, more and more applications demand to run across several clouds to satisfy the requirements like best cost efficiency, avoidance of vender lock-in, and geolocation sensitive service. JointCloud computing is a new research initiated by Chinese institutes to address the computing issues concerned with multiple clouds. In JointCloud, users＇ diverse and dynamic requirements on cloud resources axe satisfied by providing users virtual cloud （VC） for special purposes. A virtual cloud for special purposes is in essence a user＇s specific cloud working environment having the customized software stacks, configurations and computing resources readily available. This paper first introduces what is JointCloud computing and then describes the design rationales, motivation examples, mechanisms and enabling technologies of VC in JointCloud.

关键词： cloud computing JointCloud virtual cloud (VC) cloud working environment

HAG： An Energy-Proportional Data Storage Scheme for Disk Array Systems

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Journal of Computer Science & Technology 2015年第4期30卷 679-695页

作者：金培权谢希科 Christian S. Jensen 金勇岳丽华 School of Computer Science and Technology University of Science and Technology of China Hefei 230027 China Key Laboratory of Electromagnetic Space Information Chinese Academy of Sciences Hefei 230027 China Department of Computer Science Aalborg University Aalborg DK-9220 Denmark

Energy consumption has been a critical issue for data storage systems, especially for modern data centers. A recent survey has showed that power costs amount to about 50%of the total cost of ownership in a typical data center, with about 27% of the system power being consumed by storage systems. This paper aims at providing an effective solution to reducing the energy consumed by disk storage systems, by proposing a new approach to reduce the energy consumption. Differing from previous approaches, we adopt two new designs. 1） We introduce a hotness-aware and group-based system model （HAG） to organize the disks, in which all disks are partitioned into a hot group and a cold group. We only make file migration between the two groups and avoid the migration within a single group, so that we are able to reduce the total cost of file migration. 2） We use an on-demand approach to reorganize files among the disks that is based on workload change as well as the change of data hotness. We conduct trace-driven experiments involving two real and nine synthetic traces and we make detailed comparisons between our method and competitor methods according to different metrics. The results show that our method can dynamically select hot files and disks when the workload changes and that it is able to reduce energy consumption for all the traces. Furthermore, its time performance is comparable to that of the compared algorithms. In general, our method exhibits the best energy e？ciency in all experiments, and it is capable of maintaining an improved trade-off between performance and energy consumption.

关键词： energy-aware system file organization storage management

ccf走进中国电信&天翼云,共探算力互联网前沿技术

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计算机科学 2024年第5期51卷 231-231页

作者： ccf微信公众号

ccf理事长、中国工程院院士、中国科学院计算技术研究所研究员孙凝晖,中国电信集团有限公司副总经理李峻分别为活动致辞。中国电信首席科学家、云计算研究院院长吴杰主持活动。ccf秘书长唐卫清,ccf副理事长、北京并行科技股份有限公司... 详细信息

ccf理事长、中国工程院院士、中国科学院计算技术研究所研究员孙凝晖,中国电信集团有限公司副总经理李峻分别为活动致辞。中国电信首席科学家、云计算研究院院长吴杰主持活动。ccf秘书长唐卫清,ccf副理事长、北京并行科技股份有限公司董事长陈健等以及中国电信集团有限公司科创部总经理王桂荣、天翼云科技有限公司总经理胡志强等出席活动。

关键词：中国工程院院士陈健中国电信 ccf 胡志强前沿技术互联网云计算

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FCES2024第一次筹备会议于沈阳召开

计算机科学 2024年第3期51卷 264-264页

作者： ccf微信公众号

计算机教育关乎计算机学科的发展和人才培养,提升我国计算机本科教育的质量并且保持可持续发展的专业竞争力,是ccf未来计算机教育峰会(FCES)在2017年应运召开的使命。FCES至今已举办七届。会议面向全国高校计算机教育领域校领导、学院... 详细信息

计算机教育关乎计算机学科的发展和人才培养,提升我国计算机本科教育的质量并且保持可持续发展的专业竞争力,是ccf未来计算机教育峰会(FCES)在2017年应运召开的使命。FCES至今已举办七届。会议面向全国高校计算机教育领域校领导、学院院长、副院长、系主任和专家学者,近年来每届峰会都有近四百人参会,已经成为了计算机教育领域一场高规格的专业盛会。

关键词：计算机教育计算机学科计算机本科教育专业竞争力专业盛会人才培养 FCE

2023年“ccf最高科学技术奖”评选结果公告

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计算机科学 2024年第2期51卷 251-251页

作者： ccf微信公众号中国计算机学会

“ccf最高科学技术奖”授予在计算机科学、技术和工程领域取得重大突破,成就卓著、贡献巨大的资深中国计算机科技工作者。ccf奖励委员会决定授予北京航空航天大学李未教授、北京信息科技大学苏东庄教授2023年“ccf最高科学技术奖”,以... 详细信息

“ccf最高科学技术奖”授予在计算机科学、技术和工程领域取得重大突破,成就卓著、贡献巨大的资深中国计算机科技工作者。ccf奖励委员会决定授予北京航空航天大学李未教授、北京信息科技大学苏东庄教授2023年“ccf最高科学技术奖”,以表彰他们为中国计算机事业的发展做出的卓越贡献。

关键词：奖励委员会科技工作者科学技术奖计算机科学 ccf 结果公告