5,397 research outputs found
DiffNodesets: An Efficient Structure for Fast Mining Frequent Itemsets
Mining frequent itemsets is an essential problem in data mining and plays an
important role in many data mining applications. In recent years, some itemset
representations based on node sets have been proposed, which have shown to be
very efficient for mining frequent itemsets. In this paper, we propose
DiffNodeset, a novel and more efficient itemset representation, for mining
frequent itemsets. Based on the DiffNodeset structure, we present an efficient
algorithm, named dFIN, to mining frequent itemsets. To achieve high efficiency,
dFIN finds frequent itemsets using a set-enumeration tree with a hybrid search
strategy and directly enumerates frequent itemsets without candidate generation
under some case. For evaluating the performance of dFIN, we have conduct
extensive experiments to compare it against with existing leading algorithms on
a variety of real and synthetic datasets. The experimental results show that
dFIN is significantly faster than these leading algorithms.Comment: 22 pages, 13 figure
Background field method in the large expansion of scalar QED
Using the background field method, we, in the large approximation,
calculate the beta function of scalar quantum electrodynamics at the first
nontrivial order in by two different ways. In the first way, we get the
result by summing all the graphs contributing directly. In the second way, we
begin with the Borel transform of the related two point Green's function. The
main results are that the beta function is fully determined by a simple
function and can be expressed as an analytic expression with a finite radius of
convergence, and the scheme-dependent renormalized Borel transform of the two
point Green's function suffers from renormalons.Comment: 13 pages, 4 figures, 1 table, to appear in the European Physical
Journal
Entanglement Rate for Gaussian Continuous Variable Beams
We derive a general expression that quantifies the total entanglement
production rate in continuous variable systems, where a source emits two
entangled Gaussian beams with arbitrary correlators.This expression is
especially useful for situations where the source emits an arbitrary frequency
spectrum,e.g. when cavities are involved. To exemplify its meaning and
potential, we apply it to a four-mode optomechanical setup that enables the
simultaneous up- and down-conversion of photons from a drive laser into
entangled photon pairs. This setup is efficient in that both the drive and the
optomechanical up- and down-conversion can be fully resonant.Comment: 18 pages, 6 figure
- …