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Initial Implementation (initial + implementation)
Selected Abstracts369 Tflop/s molecular dynamics simulations on the petaflop hybrid supercomputer ,Roadrunner'CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 17 2009Timothy C. Germann Abstract We describe the implementation of a short-range parallel molecular dynamics (MD) code, SPaSM, on the heterogeneous general-purpose Roadrunner supercomputer. Each Roadrunner ,TriBlade' compute node consists of two AMD Opteron dual-core microprocessors and four IBM PowerXCell 8i enhanced Cell microprocessors (each consisting of one PPU and eight SPU cores), so that there are four MPI ranks per node, each with one Opteron and one Cell. We will briefly describe the Roadrunner architecture and some of the initial hybrid programming approaches that have been taken, focusing on the SPaSM application as a case study. An initial ,evolutionary' port, in which the existing legacy code runs with minor modifications on the Opterons and the Cells are only used to compute interatomic forces, achieves roughly a 2× speedup over the unaccelerated code. On the other hand, our ,revolutionary' implementation adopts a Cell-centric view, with data structures optimized for, and living on, the Cells. The Opterons are mainly used to direct inter-rank communication and perform I/O-heavy periodic analysis, visualization, and checkpointing tasks. The performance measured for our initial implementation of a standard Lennard,Jones pair potential benchmark reached a peak of 369 Tflop/s double-precision floating-point performance on the full Roadrunner system (27.7% of peak), nearly 10× faster than the unaccelerated (Opteron-only) version. Copyright © 2009 John Wiley & Sons, Ltd. [source] An architecture for Internet service via broadband satellite networksINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 1 2001Vijay G. Bharadwaj Abstract High bandwidth satellites offer the promise of a rapidly deployable communications infrastructure with a natural support for mobility. However, many widely used versions of the Transmission Control Protocol perform poorly over satellite links, and this presents an obstacle to the deployment of such systems. We present an architecture that overcomes these problems and allows easy integration of heterogeneous networks into the larger Internet. We also present some results from our initial implementation, which uses TCP connection splitting to improve TCP performance over satellite links. Copyright © 2001 John Wiley & Sons, Ltd. [source] Four "lessons learned" while implementing a multi-site caries prevention trialJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 3 2010James D. Bader DDS Abstract As the number of dental-related randomized clinical trials (RCTs) increases, there is a need for literature to help investigators inexperienced in conducting RCTs design and implement studies. This commentary describes four "lessons learned" or considerations important in the planning and initial implementation of RCTs in dentistry that, to our knowledge, have not been discussed in the general dental literature describing trial techniques. These considerations are a) preparing or securing a thorough systematic review; b) developing a comprehensive set of study documents; c) designing and testing multiple recruitment strategies; and d) employing a run-in period prior to enrollment. Attention to these considerations in the planning phases of a dental RCT can help ensure that the trial is clinically relevant while also maximizing the likelihood that its implementation will be successful. [source] Summary report of a national conference: Evolving concepts in liver allocation in the MELD and PELD eraLIVER TRANSPLANTATION, Issue S10 2004Kim M. Olthoff A national conference was held to review and assess data gathered since implementation of MELD and PELD and determine future directions. The objectives of the conference were to review the current system of liver allocation with a critical analysis of its strengths and weaknesses. Conference participants used an evidence-based approach to consider whether predicted outcome after transplantation should influence allocation, to discuss the concept of minimal listing score, to revisit current and potential expansion of exception criteria, and to determine whether specific scores should be used for automatic removal of patients on the waiting list. After review of data from the first 18 months since implementation, association and society leaders, and surgeons and hepatologists with wide regional representation were invited to participate in small group discussions focusing on each of the main objectives. At the completion of the meeting, there was agreement that MELD has had a successful initial implementation, meeting the goal of providing a system of allocation that emphasizes the urgency of the candidate while diminishing the reliance on waiting time, and that it has proven to be a powerful tool for auditing the liver allocation system. It was also agreed that the data regarding the accuracy of PELD as a predictor of pretransplant mortality were less conclusive and that PELD should be considered in isolation. Recommendations for the transplant community, based on the analysis of the MELD data, were discussed and are presented in the summary document. (Liver Transpl 2004;10:A6,A22.) [source] PUTTING THE CIVIL SOCIETY SECTOR ON THE ECONOMIC MAP OF THE WORLDANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 2 2010Lester M. Salamon ABSTRACT,:,The past twenty-five years have witnessed a spectacular expansion of philanthropy, volunteering, and civil society organizations throughout the world. Indeed, we seem to be in the midst of a ,global associational revolution,' a worldwide upsurge of organized private voluntary activity. Despite the promise that this development holds, however, the nonprofit or civil society sector remains the invisible subcontinent on the social landscape of most countries, poorly understood by policymakers and the public at large, often encumbered by legal limitations, and inadequately utilized as a mechanism for addressing public problems. One reason for this is the lack of basic information on its scope, structure, financing, and contributions in most parts of the world. This lack of information is due in part to the fact that significant components of the nonprofit sector fall within the non-observed, or informal, economy, and in part to the way even the observed parts of this sector have historically been treated in the prevailing System of National Accounts (SNA). This paper provides an overview of a series of steps that have been taken over the past 20 years by researchers at the Johns Hopkins University in cooperation with colleagues around the world and, more recently, with officials in the United Nations Statistics Division and the International Labour Organization to remedy this situation, culminating in the issuance and initial implementation of a new United Nations Handbook on Nonprofit Institutions in the System of National Accounts and the forthcoming publication of a new International Labour Organization Manual on the Measurement of Volunteer Work. Taken together, these efforts point the way toward putting the civil society sector on the economic map of the world for the first time in a systematically comparative way. [source] | ||||||||||