An investigation of the performance portability of OpenCL

This paper reports on the development of an MPI/OpenCL implementation of LU, an application-level benchmark from the NAS Parallel Benchmark Suite. An account of the design decisions addressed during the development of this code is presented, demonstrating the importance of memory arrangement and work-item/work-group distribution strategies when applications are deployed on different device types. The resulting platform-agnostic, single source application is benchmarked on a number of different architectures, and is shown to be 1.3–1.5× slower than native FORTRAN 77 or CUDA implementations on a single node and 1.3–3.1× slower on multiple nodes. We also explore the potential performance gains of OpenCL’s device fissioning capability, demonstrating up to a 3× speed-up over our original OpenCL implementation.     

Disruptive innovation for social change: how technology innovation can be best managed in social context

This paper describes a research approach based on the Actor-Network Theory (ANT) to interpret and understand the Korea’s strategy for the development of the ubiquitous city (u-city). Analyzing empirical materials from u-city development, this study traces and unpacks the interaction occurring around the u-city innovation and also identifies patterns of innovation, concentrating on negotiation and translation implementation. The findings imply that Korean approach has marginalized key issues relating to the development potential inherent in the combination of knowledge and technology and thus conflicts with broader development suggestions of participative design. Korean case reveals the essential role of participatory design in u-city development. U-city as a public utility should draw users’ perspectives, its design should be heavily grounded in users’ needs, and its design decisions should be based on a community consensus.     

基于移动边缘计算的虚拟现实压缩与传输系统

针对基于云服务的虚拟现实对数据传输速率的高要求以及对传输时延的敏感性问题,提出并设计了基于移动边缘计算技术的云VR系统方案,主要包括基于视点的VR处理和混合数模传输优化。首先采用基于金字塔投影的用户视点感知动态推流方法实现基于视点的VR处理;然后引入混合数模技术对传输进行优化改进,并给出了启发式的资源分配优化算法;最后在长期演进(LTE)系统的基础上改造基站协议栈,融入移动边缘计算技术,实现了完整的移动边缘云VR系统。实验结果表明,与已有方案相比,所提方案能够实现更加稳健高效的传输,达到更好的VR用户体验。     

5G端到端网络切片进展与挑战分析

随着5G端到端网络切片商用部署的逐步推进,在切片实施过程中遇到一些问题和挑战,因此亟需对其当前的研究进展及挑战进一步分析.从对5G端到端网络切片的系统性论述切入,首先介绍了5G网络切片的架构和功能,之后梳理了目前国内外标准组织对网络切片及其增强技术的研究进展,最后识别并深入分析了端到端网络切片面临的挑战,包括SLA保障...     

一种评价搜索引擎信息覆盖率的模型及其验证

搜索引擎的网页搜集子系统通常以WWW的网页构成的有向图结构为依据,循着网页间的链接进行搜集从而扩大信息覆盖面.本文针对这种信息覆盖能力,建立量化模型从多个角度考察搜集系统对WWW信息资源的覆盖程度.文章首先分析了网页搜集不完全性的若干因素,在指出信息覆盖率的研究意义后提出了三类重要的信息覆盖率概念,然后围绕其中的数量和质量覆盖率展开研究工作.在建立"采样-权值计算-验证"的覆盖率评测模型之后,以北大"燕穹"网页信息博物馆为考察对象并获得其网页数据,用不同的方式对中国Web进行采样;然后分别采用PageRank和HITS两种网页权值算法算出其中的重要网页作为样本,从量和质的角度考察"燕穹"系统的信息覆盖率,得到合理的数量和质量覆盖率值,从而验证了"燕穹"系统信息覆盖率结论的合理性和该信息覆盖率评测模型的可靠性.     

单沟道传输门绝热触发器和相对绝热计算原理

该文从动态功耗在工程上有界限的观点出发,讨论单沟道传输门的相对绝热计算原理。在此基础上设计单沟道和双沟道传输门动态绝热锁存器,使其保存信息时,存储介质与外界隔离。将两种绝热锁存器进行比较、分析,并用计算机模拟程序检验其结果。     

钟控准静态能量回收逻辑电路

钟控准静态能量回收逻辑 (clocked quasi- static energy recovery logic,CQSERL)只在输入信号导致输出状态发生变化的情况下才对电路节点充电 (或者回收 ) ,不需要在每个功率时钟周期循环充电和回收操作 ;CQSERL是单端输入输出逻辑 ,减小了电路实现代价 .设计了 4位 QSERL 串行进位加法器 (RCA)电路 ,和相应的 CMOS电路进行了功耗比较 .功率时钟为 10 MHz时 ,CQSERL 电路功耗是对应 CMOS电路的 35 % .流片实现了一个简单结构的正弦功率时钟产生电路 ,功率时钟的频率和相位与外接系统时钟相同     

An Efficient Time-Based Checkpointing Protocol for Mobile Computing Systems over Mobile IP

Time-based coordinated checkpointing protocols are well suited for mobile computing systems because no explicit coordination message is needed while the advantages of coordinated checkpointing are kept. However, without coordination, every process has to take a checkpoint during a checkpointing process. In this paper, an efficient time-based coordinated checkpointing protocol for mobile computing systems over Mobile IP is proposed. The protocol reduces the number of checkpoints per checkpointing process to nearly minimum, so that fewer checkpoints need to be transmitted through the costly wireless link. Our protocol also performs very well in the aspects of minimizing the number and size of messages transmitted in the wireless network. In addition, the protocol is nonblocking because inconsistencies can be avoided by the piggybacked information in every message. Therefore, the protocol brings very little overhead to a mobile host with limited resource. Additionally, by taking advantage of reliable timers in mobile support stations, the time-based checkpointing protocol can adapt to wide area networks.     

用Delphi实现快速删除TList的批连续结点算法的探讨

在编制遥测数据处理软件的过程中，面对大量的测试数据，经常需要编写高效率的数据过滤器。本文讨论了一种通过采用跨单元、跨类访问Delphi类的私有域的方法实现快速删除TList批连续结点的新算法，并通过测试结果得到验证。