842 resultados para CLUSTER TURNOFFS
氢甲酰化反应的有效双金属催化剂:Rh-Co簇合物 AN EFFECTIVE ORGANO-BIMETALLIC Rh-Co CLUSTER CATALYST FOR HYDROFORMYLATI-ON
Resumo:
An effective approach of simulating fluid dynamics on a cluster of non- dedicated workstations is presented. The approach uses local interaction algorithms, small communication capacity, and automatic migration of parallel processes from busy hosts to free hosts. The approach is well- suited for simulating subsonic flow problems which involve both hydrodynamics and acoustic waves; for example, the flow of air inside wind musical instruments. Typical simulations achieve $80\\%$ parallel efficiency (speedup/processors) using 20 HP-Apollo workstations. Detailed measurements of the parallel efficiency of 2D and 3D simulations are presented, and a theoretical model of efficiency is developed which fits closely the measurements. Two numerical methods of fluid dynamics are tested: explicit finite differences, and the lattice Boltzmann method.
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The photoionization of methyl iodide beam seeded in argon and helium is studied by time-of-flight mass spectrometry using a 25 ns, 532 nm Nd-YAG laser with intensities in the range of 2 x 10(10)-2 x 10(11) W/cm(2). Multiply charged ions Of Iq+ (q = 2-3) and C2+ with tens of eV kinetic energies have been observed when laser interacts with the middle part of the pulsed molecular beam, whose peak profiles are independent on the laser polarization directions. Strong evidences show that these ions are coming from the Coulomb explosion of multiply charged CH3I clusters, and laser induced inverse bremsstrahlung absorption of caged electrons plays a key role in the formation of multiply charged ions. (C) 2004 Elsevier B.V. All rights reserved.
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Multicharged xenon and krypton ions with charge states up to Xe11+ and Kr11+ have been observed in laser ionization of a pulsed xenon or krypton beam by a 25 ns Nd-YAG laser with laser intensity of 10(10)-10(11) W cm(-2) at 532 nm. There is strong evidence to support that those multicharged ions come from cluster-assisted electron recolliding ionizations inside the cluster after multiphoton ionization of atoms in the cluster, the electron can gain its kinetic energy by inverse bremsstrahlung absorption from a laser field quickly.
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Neal M J Timmis J and Hunt J. Data analysis with artificial immune systems, cluster analysis and kohonen networks: some comparisons. In Proceedings of IEEE international conference of systems, man and cybernetics, pages 922-927, Tokyo, 1999. IEEE.
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Cox, S.J., Vaz, M.F. and Weaire, D. (2003) Topological changes in a two-dimensional foam cluster. The European Physical Journal E - Soft Matter . 11:29-35.
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We consider the problem of performing topological optimizations of distributed hash tables. Such hash tables include Chord and Tapestry and are a popular building block for distributed applications. Optimizing topologies over one dimensional hash spaces is particularly difficult as the higher dimensionality of the underlying network makes close fits unlikely. Instead, current schemes are limited to heuristically performing local optimizations finding the best of small random set of peers. We propose a new class of topology optimizations based on the existence of clusters of close overlay members within the underlying network. By constructing additional overlays for each cluster, a significant portion of the search procedure can be performed within the local cluster with a corresponding reduction in the search time. Finally, we discuss the effects of these additional overlays on spatial locality and other load balancing scheme.
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In this paper, we propose and evaluate an implementation of a prototype scalable web server. The prototype consists of a load-balanced cluster of hosts that collectively accept and service TCP connections. The host IP addresses are advertised using the Round Robin DNS technique, allowing any host to receive requests from any client. Once a client attempts to establish a TCP connection with one of the hosts, a decision is made as to whether or not the connection should be redirected to a different host---namely, the host with the lowest number of established connections. We use the low-overhead Distributed Packet Rewriting (DPR) technique to redirect TCP connections. In our prototype, each host keeps information about connections in hash tables and linked lists. Every time a packet arrives, it is examined to see if it has to be redirected or not. Load information is maintained using periodic broadcasts amongst the cluster hosts.
Resumo:
This Portfolio is about the changes that can be supported and achieved through transformational education that impacts on personal, professional and organisational levels. Having lived through an era of tremendous change over the second half of the twentieth century and into the twenty-first the author has a great drawing board to contemplate in the context of professional career experience as an engineer. The ability to engage in ‘subject-object’ separation is the means by which Kegan (1994, 2009) explains that transformation takes place and the Essays in this Portfolio aim to support and bring about such change. Exploration of aspects of ‘Kerry’ is the material selected to both challenge support change in the way of knowing from being subject to certain information and knowledge that to being able to consider it more objectively. The task of being able to distance judgement about the economy and economic development of Kerry was facilitated by various readings around of a number of key thinkers including Kegan, Drucker, Porter and Penrose. The central themes of Kerry or the potential for economic development are built into each Essay. Essay One focuses on reflections of Kerry life - on Kerry people within and without Kerry - and events as they affected understandings of how people related to and worked with one another. These reflections formed the basis for transformational goals identified which required a shift from an engineering mindset to encompass an economics-based view. In Essay Two knowledge of economic concepts is developed by exploring the writings of Drucker, Penrose, and Porter with pertinence to considering economic development generally, and for Kerry in particular in the form of an ‘entrepreneurial platform’. The concepts and theories were the basis of explorations presented in Essays Three and Four. Essay Three focuses on Kerry’s potential for economic development give its current economic profile and includes results from interviews with selected businesses. Essay Four is an exercise in the application of Porter’s ‘Cluster’ concept to the equine sector.