9,835 research outputs found
Deep neural networks for network routing
In this work, we propose a Deep Learning (DL) based solution to the problem of routing traffic flows in computer networks. Routing decisions can be made in different ways depending on the desired objective and, based on that objective function, optimal solutions can be computed using a variety of techniques, e.g. with mixed integer linear programming. However, determining these solutions requires solving complex optimization problems and, thus, cannot be typically done at runtime. Instead, heuristics for these problems are often created but designing them is non-trivial in many cases. The routing framework proposed here presents an alternative to the design of heuristics, whilst still achieving good performance. This is done by building a DL model trained on the optimal decisions over flows from known traffic demands. To evaluate our solution, we focused on the problem of network congestion, even though a wide range of alternative objectives could be fitted into this framework. We ran experiments using two publicly available datasets of networks with real traffic demands and showed that our solution achieves close-to-optimal network congestion values.This research was sponsored by the U.S. Army Research
Laboratory and the U.K. Ministry of Defence under Agreement Number W911NF-16-3-0001.info:eu-repo/semantics/publishedVersio
Charge orderings in the atomic limit of the extended Hubbard model
The extended Hubbard model in the atomic limit (AL-EHM) on a square lattice
with periodic boundary conditions is studied with use of the Monte Carlo (MC)
method. Within the grand canonical ensemble the phase and order-order
boundaries for charge orderings are obtained. The phase diagrams include three
types of charge ordered phases and the nonordered phase. The system exhibits
very rich structure and shows unusual multicritical behavior. In the limiting
case of tij = 0, the EHM is equivalent to the pseudospin model with single-ion
anisotropy 1/2U, exchange interaction W in an effective magnetic field
(mu-1/2U-zW). This classical spin model is analyzed using the MC method for the
canonical ensemble. The phase diagram is compared with the known results for
the Blume-Capel model.Comment: 9 pages, 10 figure
Vector Competence of the Tick Ixodes ricinus for Transmission of Bartonella birtlesii
Bartonella spp. are facultative intracellular vector-borne bacteria associated with several emerging diseases in humans and animals all over the world. The potential for involvement of ticks in transmission of Bartonella spp. has been heartily debated for many years. However, most of the data supporting bartonellae transmission by ticks come from molecular and serological epidemiological surveys in humans and animals providing only indirect evidences without a direct proof of tick vector competence for transmission of bartonellae. We used a murine model to assess the vector competence of Ixodes ricinus for Bartonella birtlesii. Larval and nymphal I. ricinus were fed on a B. birtlesii-infected mouse. The nymphs successfully transmitted B. birtlesii to naïve mice as bacteria were recovered from both the mouse blood and liver at seven and 16 days after tick bites. The female adults successfully emitted the bacteria into uninfected blood after three or more days of tick attachment, when fed via membrane feeding system. Histochemical staining showed the presence of bacteria in salivary glands and muscle tissues of partially engorged adult ticks, which had molted from the infected nymphs. These results confirm the vector competence of I. ricinus for B. birtlesii and represent the first in vivo demonstration of a Bartonella sp. transmission by ticks. Consequently, bartonelloses should be now included in the differential diagnosis for patients exposed to tick bites
The four dimensional site-diluted Ising model: a finite-size scaling study
Using finite-size scaling techniques, we study the critical properties of the
site-diluted Ising model in four dimensions. We carry out a high statistics
Monte Carlo simulation for several values of the dilution. The results support
the perturbative scenario: there is only the Ising fixed point with large
logarithmic scaling corrections. We obtain, using the Perturbative
Renormalization Group, functional forms for the scaling of several observables
that are in agreement with the numerical data.Comment: 30 pages, 8 postscript figure
Nishimori point in the 2D +/- J random-bond Ising model
We study the universality class of the Nishimori point in the 2D +/- J
random-bond Ising model by means of the numerical transfer-matrix method. Using
the domain-wall free-energy, we locate the position of the fixed point along
the Nishimori line at the critical concentration value p_c = 0.1094 +/- 0.0002
and estimate nu = 1.33 +/- 0.03. Then, we obtain the exponents for the moments
of the spin-spin correlation functions as well as the value for the central
charge c = 0.464 +/- 0.004. The main qualitative result is the fact that
percolation is now excluded as a candidate for describing the universality
class of this fixed point.Comment: 4 pages REVTeX, 3 PostScript figures; final version to appear in
Phys. Rev. Lett.; several small changes and extended explanation
Duality in finite-dimensional spin glasses
We present an analysis leading to a conjecture on the exact location of the
multicritical point in the phase diagram of spin glasses in finite dimensions.
The conjecture, in satisfactory agreement with a number of numerical results,
was previously derived using an ansatz emerging from duality and the replica
method. In the present paper we carefully examine the ansatz and reduce it to a
hypothesis on analyticity of a function appearing in the duality relation. Thus
the problem is now clearer than before from a mathematical point of view: The
ansatz, somewhat arbitrarily introduced previously, has now been shown to be
closely related to the analyticity of a well-defined function.Comment: 12 pages, 3 figures; A reference added; to appear in J. Stat. Phy
a review
Women have a number of specificities that differentiate them from men. In particular, the role of sex steroid hormones and the menstrual cycle (MC) significantly impact women?s physiology.
The literature has shown nonlinear relationships between MC, exercise, and nutritional intake.
Notably, these relationships are bidirectional and less straightforward than one would suppose. For example, the theoretical implications of the MC?s phases on exercise performance do not always translate into relevant practical effects. There is often a disconnect between internal measures (e.g., levels of hormone concentrations) and external performance. Furthermore, it is not entirely clear how nutritional intake varies across the MC?s phases and whether these variations impact on exercise performance. Therefore, a thorough review of the existing knowledge could help in framing these complex relationships and potentially contribute to the optimization of exercise prescription and nutritional intake according to the naturally occurring phases of the MC. Throughout this review, an emerging trend is the lack of generalizability and the need to individualize interventions, since the consequences of the MC?s phases and their relationships with exercise and nutritional intake seem to vary greatly from person to person. In this sense, average data are probably not relevant and
could potentially be misleading.D915-7373-ED16 | Cesar LeaoN/
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