34,190 research outputs found

    Enabling Highly-Scalable Remote Memory Access Programming with MPI-3 One Sided

    Get PDF

    “Legal or Illegal? Documented or Undocumented?” The Struggle over Brookhaven’s \u3cem\u3eNeighborhood Preservation Act\u3c/em\u3e

    Get PDF
    This critical essay applies the concept of “presence” as a theoretical lens for explaining the rhetorical efficacy of protest events surrounding a contemporary debate about immigrants’ rights in a suburban New York township. Specifically, the protests surrounding the town board meetings regarding Brookhaven’s “Neighborhood Preservation Act,” a piece of legislation geared toward making rental laws more stringent, are examined. A group comprised largely of white, upper middle-class citizens voiced their support for the proposed legislation, while a group of day laborers and those sympathetic with their cause characterized the proposed legislation as a form of racial discrimination disguised as a rental law. This analysis focuses on the specific tactics used by protesters on both sides of this issue in their attempts to persuade members of the town board, the news media, and the citizens of Brookhaven township

    A review of advances in pixel detectors for experiments with high rate and radiation

    Full text link
    The Large Hadron Collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog. Phy

    “Legal or Illegal? Documented or Undocumented?” The Struggle over Brookhaven’s \u3cem\u3eNeighborhood Preservation Act\u3c/em\u3e

    Get PDF
    This critical essay applies the concept of “presence” as a theoretical lens for explaining the rhetorical efficacy of protest events surrounding a contemporary debate about immigrants’ rights in a suburban New York township. Specifically, the protests surrounding the town board meetings regarding Brookhaven’s “Neighborhood Preservation Act,” a piece of legislation geared toward making rental laws more stringent, are examined. A group comprised largely of white, upper middle-class citizens voiced their support for the proposed legislation, while a group of day laborers and those sympathetic with their cause characterized the proposed legislation as a form of racial discrimination disguised as a rental law. This analysis focuses on the specific tactics used by protesters on both sides of this issue in their attempts to persuade members of the town board, the news media, and the citizens of Brookhaven township

    Scalable Applications on Heterogeneous System Architectures: A Systematic Performance Analysis Framework

    Get PDF
    The efficient parallel execution of scientific applications is a key challenge in high-performance computing (HPC). With growing parallelism and heterogeneity of compute resources as well as increasingly complex software, performance analysis has become an indispensable tool in the development and optimization of parallel programs. This thesis presents a framework for systematic performance analysis of scalable, heterogeneous applications. Based on event traces, it automatically detects the critical path and inefficiencies that result in waiting or idle time, e.g. due to load imbalances between parallel execution streams. As a prerequisite for the analysis of heterogeneous programs, this thesis specifies inefficiency patterns for computation offloading. Furthermore, an essential contribution was made to the development of tool interfaces for OpenACC and OpenMP, which enable a portable data acquisition and a subsequent analysis for programs with offload directives. At present, these interfaces are already part of the latest OpenACC and OpenMP API specification. The aforementioned work, existing preliminary work, and established analysis methods are combined into a generic analysis process, which can be applied across programming models. Based on the detection of wait or idle states, which can propagate over several levels of parallelism, the analysis identifies wasted computing resources and their root cause as well as the critical-path share for each program region. Thus, it determines the influence of program regions on the load balancing between execution streams and the program runtime. The analysis results include a summary of the detected inefficiency patterns and a program trace, enhanced with information about wait states, their cause, and the critical path. In addition, a ranking, based on the amount of waiting time a program region caused on the critical path, highlights program regions that are relevant for program optimization. The scalability of the proposed performance analysis and its implementation is demonstrated using High-Performance Linpack (HPL), while the analysis results are validated with synthetic programs. A scientific application that uses MPI, OpenMP, and CUDA simultaneously is investigated in order to show the applicability of the analysis

    The ‘credibility paradox’ in China’s science communication: Views from scientific practitioners

    Get PDF
    In contrast to increasing debates on China’s rising status as a global scientific power, issues of China’s science communication remain under-explored. Based on 21 in-depth interviews in three cities, this article examines Chinese scientists’ accounts of the entangled web of influence which conditions the process of how scientific knowledge achieves (or fails to achieve) its civic authority. A main finding of this study is a ‘credibility paradox’ as a result of the over-politicisation of science and science communication in China. Respondents report that an absence of visible institutional endorsements renders them more public credibility and better communication outcomes. Thus, instead of exploiting formal channels of science communication, scientists interviewed were more keen to act as ‘informal risk communicators’ in grassroots and private events. Chinese scientists’ perspectives on how to earn public support of their research sheds light on the nature and impact of a ‘civic epistemology’ in an authoritarian state

    Delayed Action and Uncertain Targets. How Much Will Climate Policy Cost?

    Get PDF
    Despite the growing concern about actual on-going climate change, there is little consensus about the scale and timing of actions needed to stabilise the concentrations of greenhouse gases. Many countries are unwilling to implement effective mitigation strategies, at least in the short-term, and no agreement on an ambitious global stabilisation target has yet been reached. It is thus likely that some, if not all countries, will delay the adoption of effective climate policies. This delay will affect the cost of future policy measures that will be required to abate an even larger amount of emissions. What additional economic cost of mitigation measures will this delay imply? At the same time, the uncertainty surrounding the global stabilisation target to be achieved crucially affects short-term investment and policy decisions. What will this uncertainty cost? Is there a hedging strategy that decision makers can adopt to cope with delayed action and uncertain targets? This paper addresses these questions by quantifying the economic implications of delayed mitigation action, and by computing the optimal abatement strategy in the presence of uncertainty about a global stabilisation target (which will be agreed upon in future climate negotiations). Results point to short-term inaction as the key determinant for the economic costs of ambitious climate policies. They also indicate that there is an effective hedging strategy that could minimise the cost of climate policy under uncertainty, and that a short-term moderate climate policy would be a good strategy to reduce the costs of delayed action and to cope with uncertainty about the outcome of future climate negotiations. By contrast, an insufficient short-term effort significantly increases the costs of compliance in the long-term.Uncertainty, Climate Policy, Stabilisation Costs, Delayed Action
    corecore