22,049 research outputs found
The Most Influential Paper Gerard Salton Never Wrote
Gerard Salton is often credited with developing the vector space model
(VSM) for information retrieval (IR). Citations to Salton give the impression
that the VSM must have been articulated as an IR model sometime between
1970 and 1975. However, the VSM as it is understood today evolved over a
longer time period than is usually acknowledged, and an articulation of the
model and its assumptions did not appear in print until several years after
those assumptions had been criticized and alternative models proposed. An
often cited overview paper titled ???A Vector Space Model for Information
Retrieval??? (alleged to have been published in 1975) does not exist, and
citations to it represent a confusion of two 1975 articles, neither of which
were overviews of the VSM as a model of information retrieval. Until the
late 1970s, Salton did not present vector spaces as models of IR generally
but rather as models of specifi c computations. Citations to the phantom
paper refl ect an apparently widely held misconception that the operational
features and explanatory devices now associated with the VSM must have
been introduced at the same time it was fi rst proposed as an IR model.published or submitted for publicatio
The Zeroth Law of Thermodynamics and Volume-Preserving Conservative Dynamics with Equilibrium Stochastic Damping
We propose a mathematical formulation of the zeroth law of thermodynamics and
develop a stochastic dynamical theory, with a consistent irreversible
thermodynamics, for systems possessing sustained conservative stationary
current in phase space while in equilibrium with a heat bath. The theory
generalizes underdamped mechanical equilibrium: , with and respectively
representing phase-volume preserving dynamics and stochastic damping. The
zeroth law implies stationary distribution . We find an
orthogonality as a hallmark of the system. Stochastic
thermodynamics based on time reversal
is formulated: entropy
production ; generalized "heat" ,
being "internal energy", and "free
energy" never increases.
Entropy follows . Our formulation is shown to
be consistent with an earlier theory of P. Ao. Its contradistinctions to other
theories, potential-flux decomposition, stochastic Hamiltonian system with even
and odd variables, Klein-Kramers equation, Freidlin-Wentzell's theory, and
GENERIC, are discussed.Comment: 25 page
Two variable deformations of the Chebyshev measure
We construct one and two parameter deformations of the two dimensional
Chebyshev polynomials with simple recurrence coefficients, following the
algorithm in [3]. Using inverse scattering techniques, we compute the
corresponding orthogonality measures.Comment: 16 page
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