1,844 research outputs found
A Comparison of Blocking Methods for Record Linkage
Record linkage seeks to merge databases and to remove duplicates when unique
identifiers are not available. Most approaches use blocking techniques to
reduce the computational complexity associated with record linkage. We review
traditional blocking techniques, which typically partition the records
according to a set of field attributes, and consider two variants of a method
known as locality sensitive hashing, sometimes referred to as "private
blocking." We compare these approaches in terms of their recall, reduction
ratio, and computational complexity. We evaluate these methods using different
synthetic datafiles and conclude with a discussion of privacy-related issues.Comment: 22 pages, 2 tables, 7 figure
Charge injection instability in perfect insulators
We show that in a macroscopic perfect insulator, charge injection at a
field-enhancing defect is associated with an instability of the insulating
state or with bistability of the insulating and the charged state. The effect
of a nonlinear carrier mobility is emphasized. The formation of the charged
state is governed by two different processes with clearly separated time
scales. First, due to a fast growth of a charge-injection mode, a localized
charge cloud forms near the injecting defect (or contact). Charge injection
stops when the field enhancement is screened below criticality. Secondly, the
charge slowly redistributes in the bulk. The linear instability mechanism and
the final charged steady state are discussed for a simple model and for
cylindrical and spherical geometries. The theory explains an experimentally
observed increase of the critical electric field with decreasing size of the
injecting contact. Numerical results are presented for dc and ac biased
insulators.Comment: Revtex, 7pages, 4 ps figure
Superconducting MgB(2) films via precursor post-processing approach
Superconducting MgB(2) films with Tc = 38.6 K were prepared using a
precursor-deposition, ex-situ post-processing approach. Precursor films of
boron, ~0.5 micrometer thick, were deposited onto Al(2)O(3) (102) substrates by
e-beam evaporation; a post-anneal at 890 deg C in the presence of bulk MgB(2)
and Mg metal produced highly crystalline MgB(2) films. X-ray diffraction
indicated that the films exhibit some degree of c-axis alignment, but are
randomly oriented in-plane. Transport current measurements of the
superconducting properties show high values of the critical current density and
yield an irreversibility line that exceeds that determined by magnetic
measurements on bulk polycrystalline materials.Comment: PDF file with 10 pages total, including 4 figure
Symmetry of two terminal, non-linear electric conduction
The well-established symmetry relations for linear transport phenomena can
not, in general, be applied in the non-linear regime. Here we propose a set of
symmetry relations with respect to bias voltage and magnetic field for the
non-linear conductance of two-terminal electric conductors. We experimentally
confirm these relations using phase-coherent, semiconductor quantum dots.Comment: 4 pages, 4 figure
New supersymmetric quartet of nuclei in the A=190 mass region
We present evidence for a new supersymmetric quartet in the A=190 region of
the nuclear mass table. New experimental information on transfer and neutron
capture reactions to the odd-odd nucleaus 194 Ir strongly suggests the
existence of a new supersymmetric quartet, consisting of the 192,193 Os and
193,194 Ir nuclei. We make explicit predictions for the odd-neutron nucleus 193
Os, and suggest that its spectroscopic properties be measured in dedicated
experiments.Comment: 5 pages, 4 figures, updated figures and revised text, Physical Review
C, Rapid Communication, in pres
Partial Densities of States, Scattering Matrices, and Green's Functions
The response of an arbitrary scattering problem to quasi-static perturbations
in the scattering potential is naturally expressed in terms of a set of local
partial densities of states and a set of sensitivities each associated with one
element of the scattering matrix. We define the local partial densities of
states and the sensitivities in terms of functional derivatives of the
scattering matrix and discuss their relation to the Green's function. Certain
combinations of the local partial densities of states represent the injectivity
of a scattering channel into the system and the emissivity into a scattering
channel. It is shown that the injectivities and emissivities are simply related
to the absolute square of the scattering wave-function. We discuss also the
connection of the partial densities of states and the sensitivities to
characteristic times. We apply these concepts to a delta-barrier and to the
local Larmor clock.Comment: 13 pages (revtex), 4 figure
Generalized Bayesian Record Linkage and Regression with Exact Error Propagation
Record linkage (de-duplication or entity resolution) is the process of
merging noisy databases to remove duplicate entities. While record linkage
removes duplicate entities from such databases, the downstream task is any
inferential, predictive, or post-linkage task on the linked data. One goal of
the downstream task is obtaining a larger reference data set, allowing one to
perform more accurate statistical analyses. In addition, there is inherent
record linkage uncertainty passed to the downstream task. Motivated by the
above, we propose a generalized Bayesian record linkage method and consider
multiple regression analysis as the downstream task. Records are linked via a
random partition model, which allows for a wide class to be considered. In
addition, we jointly model the record linkage and downstream task, which allows
one to account for the record linkage uncertainty exactly. Moreover, one is
able to generate a feedback propagation mechanism of the information from the
proposed Bayesian record linkage model into the downstream task. This feedback
effect is essential to eliminate potential biases that can jeopardize resulting
downstream task. We apply our methodology to multiple linear regression, and
illustrate empirically that the "feedback effect" is able to improve the
performance of record linkage.Comment: 18 pages, 5 figure
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