13,571 research outputs found
Farm practices and their effects on farm earnings
Includes bibliographical references
TOPEX satellite concept. TOPEX option study report
Candidate bus equipment from the Viking, Applications Explorer Mission, and Small Scientific Satellite programs for application to the TOPEX mission options is assessed. Propulsion module equipment and subsystem candidates from the Applications Explorer Mission satellites and the Small Scientific Satellite spacecraft are evaluated for those TOPEX options. Several subsystem concepts appropriate to the TOPEX options are described. These descriptions consider performance characteristics of the subsystems. Cost and availability information on the candidate equipment and subsystems are also provided
Combining Models of Approximation with Partial Learning
In Gold's framework of inductive inference, the model of partial learning
requires the learner to output exactly one correct index for the target object
and only the target object infinitely often. Since infinitely many of the
learner's hypotheses may be incorrect, it is not obvious whether a partial
learner can be modifed to "approximate" the target object.
Fulk and Jain (Approximate inference and scientific method. Information and
Computation 114(2):179--191, 1994) introduced a model of approximate learning
of recursive functions. The present work extends their research and solves an
open problem of Fulk and Jain by showing that there is a learner which
approximates and partially identifies every recursive function by outputting a
sequence of hypotheses which, in addition, are also almost all finite variants
of the target function.
The subsequent study is dedicated to the question how these findings
generalise to the learning of r.e. languages from positive data. Here three
variants of approximate learning will be introduced and investigated with
respect to the question whether they can be combined with partial learning.
Following the line of Fulk and Jain's research, further investigations provide
conditions under which partial language learners can eventually output only
finite variants of the target language. The combinabilities of other partial
learning criteria will also be briefly studied.Comment: 28 page
An Inverse Scattering Transform for the Lattice Potential KdV Equation
The lattice potential Korteweg-de Vries equation (LKdV) is a partial
difference equation in two independent variables, which possesses many
properties that are analogous to those of the celebrated Korteweg-de Vries
equation. These include discrete soliton solutions, Backlund transformations
and an associated linear problem, called a Lax pair, for which it provides the
compatibility condition. In this paper, we solve the initial value problem for
the LKdV equation through a discrete implementation of the inverse scattering
transform method applied to the Lax pair. The initial value used for the LKdV
equation is assumed to be real and decaying to zero as the absolute value of
the discrete spatial variable approaches large values. An interesting feature
of our approach is the solution of a discrete Gel'fand-Levitan equation.
Moreover, we provide a complete characterization of reflectionless potentials
and show that this leads to the Cauchy matrix form of N-soliton solutions
Performance of cylindrical converters with preferred-crystal-orientation emitters of chemically vapor deposited tungsten
Design and evaluation of cylindrical out-of-pile thermionic converter test vehicle to determine performance of tungsten emitters with preferred crystal orientatio
Comparing Wealth Effects: The Stock Market versus the Housing Market
We examine the link between increases in housing wealth, financial wealth, and consumer spending. We rely upon a panel of 14 countries observed annually for various periods during the past 25 years and a panel of U.S. states observed quarterly during the 1980s and 1990s. We impute the aggregate value of owner-occupied housing, the value of financial assets, and measures of aggregate consumption for each of the geographic units over time. We estimate regressions relating consumption to income and wealth measures, finding a statistically significant and rather large effect of housing wealth upon household consumption.Consumption, nonfinancial wealth, housing market, real estate
Comparing Wealth Effects: The Stock Market Versus the Housing Market
We examine the link between increases in housing wealth, financial wealth, and consumer spending. We rely upon a panel of 14 countries observed annually for various periods during the past 25 years and a panel of U.S. states observed quarterly during the 1980s and 1990s. We impute the aggregate value of owner-occupied housing, the value of financial assets, and measures of aggregate consumption for each of the geographic units over time. We estimate regressions relating consumption to income and wealth measures, finding a statistically significant and rather large effect of housing wealth upon household consumption.
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