487,690 research outputs found
Muscogiana Vol. 4(1&2), Summer 1993
https://csuepress.columbusstate.edu/muscogiana/1016/thumbnail.jp
Cold-air investigation of a 4 1/2 stage turbine with stage-loading factor of 4.66 and high specific work output. 2: Stage group performance
The stage group performance of a 4 1/2 stage turbine with an average stage loading factor of 4.66 and high specific work output was determined in cold air at design equivalent speed. The four stage turbine configuration produced design equivalent work output with an efficiency of 0.856; a barely discernible difference from the 0.855 obtained for the complete 4 1/2 stage turbine in a previous investigation. The turbine was designed and the procedure embodied the following design features: (1) controlled vortex flow, (2) tailored radial work distribution, and (3) control of the location of the boundary-layer transition point on the airfoil suction surface. The efficiency forecast for the 4 1/2 stage turbine was 0.886, and the value predicted using a reference method was 0.862. The stage group performance results were used to determine the individual stage efficiencies for the condition at which design 4 1/2 stage work output was obtained. The efficiencies of stages one and four were about 0.020 lower than the predicted value, that of stage two was 0.014 lower, and that of stage three was about equal to the predicted value. Thus all the stages operated reasonably close to their expected performance levels, and the overall (4 1/2 stage) performance was not degraded by any particularly inefficient component
Scrapbook RF/1/4/1/2: 1948
Ruth First's scrapbook of newspaper cuttings from 1948. Many articles are unauthored
Sum-of-Squares Certificates for Maxima of Random Tensors on the Sphere
For an -variate order- tensor , define to be the maximum value taken by the
tensor on the unit sphere. It is known that for a random tensor with i.i.d entries, w.h.p. We study the
problem of efficiently certifying upper bounds on via the natural
relaxation from the Sum of Squares (SoS) hierarchy. Our results include:
- When is a random order- tensor, we prove that levels of SoS
certifies an upper bound on that satisfies Our upper bound improves a result of Montanari and Richard
(NIPS 2014) when is large.
- We show the above bound is the best possible up to lower order terms,
namely the optimum of the level- SoS relaxation is at least
- When is a random order- tensor, we prove that levels of SoS
certifies an upper bound on that satisfies For growing , this improves upon the bound
certified by constant levels of SoS. This answers in part, a question posed by
Hopkins, Shi, and Steurer (COLT 2015), who established the tight
characterization for constant levels of SoS
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