3,571 research outputs found
Improved design of queueing simulation experiments with highly heteroscedastic responses
No full textSimulation experiments for analysing the steady-state behaviour of queueing systems over a range of traffic intensities are considered, and a procedure is presented for improving their design. In such simulations the mean and variance of the response output can increase dramatically with traffic intensity; the design has to be able to cope with this complication. A regression metamodel of the likely mean response is used consisting of two factors, namely, a low-degree polynomial and a factor accounting for the exploding mean as the traffic intensity approaches its saturation. The best choice of traffic intensities at which to make simulation runs depends on the variability of the simulation output, and this variability is estimated using analytical heavy traffic results. The optimal numbers of customers simulated at each traffic intensity are built up using a multistage procedure. The asymptotic properties of the procedure are investigated theoretically. The procedure is shown to be robust and to be more efficient than more naive procedures. A result of note is that even when the range of interest includes high traffic intensities, the highest traffic load simulated should remain well away from its upper limit; but the number of customers simulated should be concentrated at the higher traffic intensities used. Empirical results are included for simulations of a single server queue with different priority rules and for a complicated queueing network. These results support the theoretical results, demonstrating that the proposed procedure can increase the accuracy of the estimated metamodel significantly compared with more naive methods
Multi-Strengthening Effects on The Martensitic Transformation Temperatures of TiNi Shape Memory Alloys
No full textGovernment Subsidy and Cost Efficiency of Financial Institutions: The Case of Farmers' Credit Unions in Taiwan
No full textX-Ray Instrumentation in Medicine and Biology, Plasma Physics, Astrophysics, and Synchrotron Radiation
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Interview With P.C. Hodgell
Full text linkP.C. Hodgell, author of God Stalk and Dark of the Moon, was one of the many authors who attended Mythcon XIX in Berkeley last summer. She was good enough to meet with the Mythic Circle writers\u27 roundtable and share some of her experiences with us. The following is transcribed from a low-quality tape; when it was possible to recognize a speaker’s voice I have identified them - others are noted as ct. Hope you enjoy it
Three-dimensional reconstructions of Zea mays stem by magnetic resonance imaging (MRI) technology
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Effects of Cr underlayer and Pt buffer layer on the interfacial structure and magnetic characteristics of sputtered FePt films
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