704 research outputs found
A New Family of Multistep Methods with Improved Phase Lag Characteristics for the Integration of Orbital Problems
In this work we introduce a new family of ten-step linear multistep methods
for the integration of orbital problems. The new methods are constructed by
adopting a new methodology which improves the phase lag characteristics by
vanishing both the phase lag function and its first derivatives at a specific
frequency. The efficiency of the new family of methods is proved via error
analysis and numerical applications.Comment: 21 pages, 3 figures, 1 tabl
Will gravitational waves confirm Einstein's General Relativity?
Even if Einstein's General Relativity achieved a great success and overcame
lots of experimental tests, it also showed some shortcomings and flaws which
today advise theorists to ask if it is the definitive theory of gravity. In
this proceeding paper it is shown that, if advanced projects on the detection
of Gravitational Waves (GWs) will improve their sensitivity, allowing to
perform a GWs astronomy, accurate angular and frequency dependent response
functions of interferometers for GWs arising from various Theories of Gravity,
i.e. General Relativity and Extended Theories of Gravity, will be the ultimate
test for General Relativity. This proceeding paper is also a short review of
the Essay which won Honorable Mention at the 2009 Gravity Research Foundation
Awards.Comment: To appear in Proceedings of the 7th International Conference of
Numerical Analysis and Applied Mathematics, Rethymno, Crete (near to Chania),
Greece, 18-22 September 200
Reducing Spatial Data Complexity for Classification Models
Intelligent data analytics gradually becomes a day-to-day reality of today's businesses. However, despite rapidly
increasing storage and computational power current state-of-the-art predictive models still can not handle massive and noisy
corporate data warehouses. What is more adaptive and real-time operational environment requires multiple models to be
frequently retrained which fiirther hinders their use. Various data reduction techniques ranging from data sampling up to
density retention models attempt to address this challenge by capturing a summarised data structure, yet they either do
not account for labelled data or degrade the classification performance of the model trained on the condensed dataset. Our
response is a proposition of a new general framework for reducing the complexity of labelled data by means of controlled
spatial redistribution of class densities in the input space. On the example of Parzen Labelled Data Compressor (PLDC) we
demonstrate a simulatory data condensation process directly inspired by the electrostatic field interaction where the data are
moved and merged following the attracting and repelling interactions with the other labelled data. The process is controlled
by the class density function built on the original data that acts as a class-sensitive potential field ensuring preservation of
the original class density distributions, yet allowing data to rearrange and merge joining together their soft class partitions.
As a result we achieved a model that reduces the labelled datasets much further than any competitive approaches yet with
the maximum retention of the original class densities and hence the classification performance. PLDC leaves the reduced
dataset with the soft accumulative class weights allowing for efficient online updates and as shown in a series of experiments
if coupled with Parzen Density Classifier (PDC) significantly outperforms competitive data condensation methods in terms of
classification performance at the comparable compression levels
Analytic Approach for Controlling Realistic Quantum Chaotic Systems
An analytic approach for controlling quantum states, which was originally
applied to fully random matrix systems [T. Takami and H. Fujisaki, Phys. Rev. E
75, 036219 (2007)], is extended to deal with more realistic quantum systems
with a banded random matrix (BRM). The validity of the new analytic field is
confirmed by directly solving the Schroedinger equation with a BRM interaction.
We find a threshold of the width of the BRM for the quantum control to be
successful.Comment: 4 pages with 4 PostScript figures, to appear in the Proceedings of
ICCMSE 2007 in a section of Symposium 8 "Quantum Control and Light-Matter
Interactions: Recent Computational and Theoretical Results
Fast cooling of trapped ions using the dynamical Stark shift gate
A laser cooling scheme for trapped ions is presented which is based on the
fast dynamical Stark shift gate, described in [Jonathan etal, PRA 62, 042307].
Since this cooling method does not contain an off resonant carrier transition,
low final temperatures are achieved even in traveling wave light field. The
proposed method may operate in either pulsed or continuous mode and is also
suitable for ion traps using microwave addressing in strong magnetic field
gradients.Comment: 4 pages 5 figure
Gravitomagnetic effect in gravitational waves
After an introduction emphasizing the importance of the gravitomag- netic
effect in general relativity, with a resume of some space-based appli- cations,
we discuss the so-called magnetic components of gravitational waves (GWs),
which have to be taken into account in the context of the total response
functions of interferometers for GWs propagating from ar- bitrary directions.Comment: To appear in Proceedings of the 7th International Conference of
Numerical Analysis and Applied Mathematics, Rethymno, Crete (near to Chania),
Greece, 18-22 September 200
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