1,120 research outputs found

    Online Learning Algorithm for Time Series Forecasting Suitable for Low Cost Wireless Sensor Networks Nodes

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    Time series forecasting is an important predictive methodology which can be applied to a wide range of problems. Particularly, forecasting the indoor temperature permits an improved utilization of the HVAC (Heating, Ventilating and Air Conditioning) systems in a home and thus a better energy efficiency. With such purpose the paper describes how to implement an Artificial Neural Network (ANN) algorithm in a low cost system-on-chip to develop an autonomous intelligent wireless sensor network. The present paper uses a Wireless Sensor Networks (WSN) to monitor and forecast the indoor temperature in a smart home, based on low resources and cost microcontroller technology as the 8051MCU. An on-line learning approach, based on Back-Propagation (BP) algorithm for ANNs, has been developed for real-time time series learning. It performs the model training with every new data that arrive to the system, without saving enormous quantities of data to create a historical database as usual, i.e., without previous knowledge. Consequently to validate the approach a simulation study through a Bayesian baseline model have been tested in order to compare with a database of a real application aiming to see the performance and accuracy. The core of the paper is a new algorithm, based on the BP one, which has been described in detail, and the challenge was how to implement a computational demanding algorithm in a simple architecture with very few hardware resources.Comment: 28 pages, Published 21 April 2015 at MDPI's journal "Sensors

    Vacuum Induced CP Violation Generating a Complex CKM Matrix with Controlled Scalar FCNC

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    We propose a viable minimal model with spontaneous CP violation in the framework of a Two Higgs Doublet Model. The model is based on a generalised Branco-Grimus-Lavoura model with a flavoured Z2\mathbb{Z}_2 symmetry, under which two of the quark families are even and the third one is odd. The lagrangian respects CP invariance, but the vacuum has a CP violating phase, which is able to generate a complex CKM matrix, with the rephasing invariant strength of CP violation compatible with experiment. The question of scalar mediated flavour changing neutral couplings is carefully studied. In particular we point out a deep connection between the generation of a complex CKM matrix from a vacuum phase and the appearance of scalar FCNC. The scalar sector is presented in detail, showing that the new scalars are necessarily lighter than 1 TeV. A complete analysis of the model including the most relevant constraints is performed, showing that it is viable and that it has definite implications for the observation of New Physics signals in, for example, flavour changing Higgs decays or the discovery of the new scalars at the LHC. We give special emphasis to processes like thc,hut\to {\rm h} c,{\rm h} u, as well as hbs,bd{\rm h}\to bs, bd, which are relevant for the LHC and the ILC.Comment: 36 pages, 11 figure

    The signal of ill-defined CPT weakening entanglement in the BdB_d system

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    In the presence of quantum gravity fluctuations (space-time foam), the CPT operator may be ill-defined. Its perturbative treatment leads to a modification of the Einstein-Podolsky-Rosen correlation of the neutral meson system by adding an Entanglement-weakening term of the wrong exchange symmetry, the ω\omega-effect. In the current paper we identify how to probe the complex ω\omega in the entangled BdB_d-system using Flavour(f)-CP(g) eigenstate decay channels: the connection between the Intensities for the two time-ordered decays (f, g) and (g, f) is lost. Appropriate observables are constructed allowing independent experimental determinations of Re(ω\omega) and Im(ω\omega), disentangled from CPT violation in the evolution Hamiltonian Re(θ\theta) and Im(θ\theta). 2-σ\sigma tensions for both Re(θ\theta) and Im(ω\omega) are shown to be uncorrelated.Comment: 18 pages, 4 figures, 1 tabl

    Vector-like Quarks at the Origin of Light Quark Masses and Mixing

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    We show how a novel fine-tuning problem present in the Standard Model can be solved through the introduction of a single flavour symmetry G, together with three Q=1/3Q = - 1/3 quarks, three Q=2/3Q = 2/3 quarks, as well as a complex singlet scalar. The symmetry G is extended to the additional fields and it is an exact symmetry of the Lagrangian, only spontaneously broken by the vacuum. Specific examples are given and a phenomenological analysis of the main features of the model is presented. It is shown that even for vector-like quarks with masses accessible at the LHC, one can have realistic quark masses and mixing, while respecting the strict constraints on process arising from flavour changing neutral currents (FCNC). The vector-like quark decay channels are also described.Comment: 25 pages, no figure

    Algunas consideraciones sobre la masa (o masa no hay más que una)

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    This article presents sorne reasoned arguments against relativistic mass as a basic concept in Theory of Special Relativity. Relativistic mass limitations are examined and invariant mass is defended as the only one. Finally, a didactic proposal, consistent with the use of invariable mass, is presented in order to introducing rnass and energy concepts at Bachillerato
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