59,242 research outputs found
Adaptive Sequential Optimization with Applications to Machine Learning
A framework is introduced for solving a sequence of slowly changing
optimization problems, including those arising in regression and classification
applications, using optimization algorithms such as stochastic gradient descent
(SGD). The optimization problems change slowly in the sense that the minimizers
change at either a fixed or bounded rate. A method based on estimates of the
change in the minimizers and properties of the optimization algorithm is
introduced for adaptively selecting the number of samples needed from the
distributions underlying each problem in order to ensure that the excess risk,
i.e., the expected gap between the loss achieved by the approximate minimizer
produced by the optimization algorithm and the exact minimizer, does not exceed
a target level. Experiments with synthetic and real data are used to confirm
that this approach performs well.Comment: submitted to ICASSP 2016, extended versio
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Lepidochelys kempii
Number of Pages: 8Integrative BiologyGeological Science
Irreducible completely pointed modules of quantum groups of type
We give a classification of all irreducible completely pointed
modules over a characteristic zero field in which
is not a root of unity. This generalizes the classification result of
Benkart, Britten and Lemire in the non quantum case. We also show that any
infinite-dimensional irreducible completely pointed
can be obtained from some irreducible completely pointed module over the
quantized Weyl algebra .Comment: 25 page
Characteristics of a variable spaced planar thermionic converter with a tungsten emitter and a niobium collector
Current-voltage characteristics of variable spaced thermionic converter with tungsten emitter and niobium collecto
Lattice theory of finite-size effects above the upper critical dimension
We present a perturbative calculation of finite-size effects near of
the lattice model in a -dimensional cubic geometry of size with
periodic boundary conditions for . The structural differences between
the lattice theory and the field theory found previously in
the spherical limit are shown to exist also for a finite number of components
of the order parameter. The two-variable finite-size scaling functions of the
field theory are nonuniversal whereas those of the lattice theory are
independent of the nonuniversal model parameters.One-loop results for
finite-size scaling functions are derived. Their structure disagrees with the
single-variable scaling form of the lowest-mode approximation for any finite
where is the bulk correlation length. At , the large-
behavior becomes lowest-mode like for the lattice model but not for the
field-theoretic model. Characteristic temperatures close to of the
lattice model, such as of the maximum of the susceptibility
, are found to scale asymptotically as ,
in agreement with previous Monte Carlo (MC) data for the five-dimensional Ising
model. We also predict asymptotically. On a
quantitative level, the asymptotic amplitudes of this large - behavior close
to have not been observed in previous MC simulations at because
of nonnegligible finite-size terms caused by the
inhomogeneous modes. These terms identify the possible origin of a significant
discrepancy between the lowest-mode approximation and previous MC data. MC data
of larger systems would be desirable for testing the magnitude of the
and terms predicted by our theory.Comment: Accepted in Int. J. Mod. Phys.
Business strategy and firm performance: the British corporate economy, 1949-1984
There has been considerable and ongoing debate about the performance of the British economy since 1945. Empirical studies have concentrated on aggregate or industry level indicators. Few have examined individual firms’ financial performance. This study takes a sample of c.3000 firms in 19 industries and identifies Britain’s best performing companies over a period of 35 years. Successful companies are defined as a) those that survive as independent entities, b) that outperform peer group average return to capital for that industry, and c) that outperform other firms in the economy according to return on capital relative to industry average. Results are presented as league tables of success and some tentative explanations offered concerning the common strategies of successful firms. A broader research agenda for British business history is suggested
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