136 research outputs found
Alternative method to find orbits in chaotic systems
We present here a new method which applies well ordered symbolic dynamics to
find unstable periodic and non-periodic orbits in a chaotic system. The method
is simple and efficient and has been successfully applied to a number of
different systems such as the H\'enon map, disk billiards, stadium billiard,
wedge billiard, diamagnetic Kepler problem, colinear Helium atom and systems
with attracting potentials. The method seems to be better than earlier applied
methods.Comment: 5 pages, uuencoded compressed tar PostScript fil
FOCALE: A Novel Autonomic Networking Architecture
Network resources will always be heterogeneous, and thus have different
functionalities and programming models. This can be solved through the
combination of information models and knowledge engineering, which together
can be used to discover and program semantically similar functionality for
heterogeneous devices regardless of the data and language used by each device.
This paper introduces FOCALE, a semantically rich architecture for orchestrating
the behavior of heterogeneous and distributed computing resources. We apply the
FOCALE architecture to Beyond 3G Networks as a case study
Chaos in a Relativistic 3-body Self-Gravitating System
We consider the 3-body problem in relativistic lineal gravity and obtain an
exact expression for its Hamiltonian and equations of motion. While
general-relativistic effects yield more tightly-bound orbits of higher
frequency compared to their non-relativistic counterparts, as energy increases
we find in the equal-mass case no evidence for either global chaos or a
breakdown from regular to chaotic motion, despite the high degree of
non-linearity in the system. We find numerical evidence for a countably
infinite class of non-chaotic orbits, yielding a fractal structure in the outer
regions of the Poincare plot.Comment: 9 pages, LaTex, 3 figures, final version to appear in Phys. Rev. Let
Association of Phosphodiesterase-5 Inhibitors Versus Alprostadil With Survival in Men With Coronary Artery Disease
Abstract Background Phosphodiesterase 5 inhibitor (PDE5i) treatment is associated with reduced mortality compared with no treatment for erectile dysfunction after myocardial infarction (MI). Objectives This study sought to investigate the association between treatment with PDE5i or alprostadil and outcomes in men with stable coronary artery disease. Methods All Swedish men with a prior MI or revascularization who received PDE5i or alprostadil during 2006 through 2013 at >6 months after the event were included, using the Swedish Patient Register and the Swedish Prescribed Drug Register. Cox regression was used to estimate adjusted hazard ratios with 95% confidence intervals for all-cause mortality, MI, heart failure, cardiovascular mortality, noncardiovascular mortality, cardiac revascularization, peripheral arterial disease, and stroke in men treated with PDE5i versus alprostadil. Results This study included 16,548 men treated with PDE5i and 1,994 treated with alprostadil. The mean follow-up was 5.8 years, with 2,261 deaths (14%) in the PDE5i group and 521 (26%) in the alprostadil group. PDE5i compared with alprostadil treatment was associated with lower mortality (hazard ratio: 0.88; 95% confidence interval: 0.79 to 0.98) and with similar associations for MI, heart failure, cardiovascular mortality, and revascularization. When quintiles (q) of filled PDE5i prescriptions were compared using q1 as reference, patients in q3, q4, and q5 had lower all-cause mortality. Among alprostadil users, those in q5 had a lower all-cause mortality compared to q1. Conclusions In men with stable coronary artery disease, treatment with PDE5i is associated with lower risks of death, MI, heart failure, and revascularization compared with alprostadil treatment. Although the decrease in all-cause mortality was PDE5i dose dependent, the data do not permit the inference of causality or any clinical benefits of PDE5i because of the observational study design
End-to-End Model Driven Policy Based Network Management
The continued movement towards converged networks changes the focus to building application services that enable customers to move between different types of service providers based on their needs. Policy management becomes paramount for the rapid deployment and management of these application services. This paper presents the concept of a policy continuum and discusses the importance of modelling and natural languages in the presence of the policy continuum, resulting in a novel architecture suitable for autonomic computing
Ontology-Based Knowledge Representation for Self-Governing Systems
Self-governing systems need a reliable set of semantics and
a formal theoretic model in order to facilitate automated reasoning. We
present an ontology-based knowledge representation that will use data
from information models while preserving the semantics and the taxonomy
of existing systems. This will facilitate the decomposition and
validation of high level goals by autonomous, self-governing components.
Our solution reuses principles and standards from the Semantic Web
and the OMG to precisely describe the managed entities and the shared
objectives that these entities are trying to achieve by autonomously correlating
their behavior. We describe how we created UML2, MOF, OCL
and QVT ontologies, and we give a case study using the NGOSS Shared
Information and Data model. We also set the requirements for integrating
existing information models and domain ontologies into a unique
knowledge base
Evaluation de l’exposition tabagique chez un groupe de « fumeurs actifs » et un groupe de « fumeurs passifs ».
La fumée de cigarette expose les fumeurs et leur entourage, à des substances chimiques toxiques responsables de maladies graves voire mortelles. L’évaluation de l’exposition au tabac permet d’apprécier le degré de dépendance et l’intensité de l’imprégnation tabagique.Notre étude porte sur l’évaluation de cette exposition chez un groupe de fumeurs chroniques et un groupe de « fumeurs passifs »et ceci par détermination des marqueurs du tabagisme :-Evaluer les taux de nicotine et de cotinine urinaires chez l’ensemble des sujets par chromatographie liquide haute performance (HPLC-DAD) utilisant une méthode d’extraction en phase solide (SPE) ;-Evaluer le taux de la carboxyhémoglobine chez ces sujets ; -Evaluer certains paramètres biochimiques (bilan lipidique et glycémie) et hémobiologiques (numération sanguine) chez ces sujets ; relever les perturbations éventuelles
Chaos in an Exact Relativistic 3-body Self-Gravitating System
We consider the problem of three body motion for a relativistic
one-dimensional self-gravitating system. After describing the canonical
decomposition of the action, we find an exact expression for the 3-body
Hamiltonian, implicitly determined in terms of the four coordinate and momentum
degrees of freedom in the system. Non-relativistically these degrees of freedom
can be rewritten in terms of a single particle moving in a two-dimensional
hexagonal well. We find the exact relativistic generalization of this
potential, along with its post-Newtonian approximation. We then specialize to
the equal mass case and numerically solve the equations of motion that follow
from the Hamiltonian. Working in hexagonal-well coordinates, we obtaining
orbits in both the hexagonal and 3-body representations of the system, and plot
the Poincare sections as a function of the relativistic energy parameter . We find two broad categories of periodic and quasi-periodic motions that we
refer to as the annulus and pretzel patterns, as well as a set of chaotic
motions that appear in the region of phase-space between these two types.
Despite the high degree of non-linearity in the relativistic system, we find
that the the global structure of its phase space remains qualitatively the same
as its non-relativisitic counterpart for all values of that we could
study. However the relativistic system has a weaker symmetry and so its
Poincare section develops an asymmetric distortion that increases with
increasing . For the post-Newtonian system we find that it experiences a
KAM breakdown for : above which the near integrable regions
degenerate into chaos.Comment: latex, 65 pages, 36 figures, high-resolution figures available upon
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