1,795 research outputs found
Positioning by multicell fingerprinting in urban NB-IoT networks
Narrowband Internet of Things (NB-IoT) has quickly become a leading technology in the deployment of IoT systems and services, owing to its appealing features in terms of coverage and energy efficiency, as well as compatibility with existing mobile networks. Increasingly, IoT services and applications require location information to be paired with data collected by devices; NB-IoT still lacks, however, reliable positioning methods. Time-based techniques inherited from long-term evolution (LTE) are not yet widely available in existing networks and are expected to perform poorly on NB-IoT signals due to their narrow bandwidth. This investigation proposes a set of strategies for NB-IoT positioning based on fingerprinting that use coverage and radio information from multiple cells. The proposed strategies were evaluated on two large-scale datasets made available under an open-source license that include experimental data from multiple NB-IoT operators in two large cities: Oslo, Norway, and Rome, Italy. Results showed that the proposed strategies, using a combination of coverage and radio information from multiple cells, outperform current state-of-the-art approaches based on single cell fingerprinting, with a minimum average positioning error of about 20 m when using data for a single operator that was consistent across the two datasets vs. about 70 m for the current state-of-the-art approaches. The combination of data from multiple operators and data smoothing further improved positioning accuracy, leading to a minimum average positioning error below 15 m in both urban environments
Comment on ``Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions''
We point out that if the majoron-like scheme is implemented within a 331
model, there must exist at least three different mass scales for the scalar
vacuum expectation values in the model.Comment: 4 pages, no figures, Revtex. To be published in Physical Review
Linking solar and long baseline terrestrial neutrino experiments
We show that in the framework of three light neutrino species with
hierarchical masses and assuming no fine tuning between the entries of the
neutrino mass matrix, one can use the solar neutrino data to obtain information
on the element of the lepton mixing matrix. Conversely, a measurement
of in atmospheric or long baseline accelerator or reactor neutrino
experiments would help discriminate between possible oscillation solutions of
the solar neutrino problem.Comment: revtex, 4 pages, no figures. Discussion of the LOW solution modified;
results unchanged. References adde
Spontaneous R-Parity violation bounds
We investigate bounds from tree-level and one-loop processes in generic
supersymmetric models with spontaneous R-parity breaking in the superpotential.
We analyse the bounds from a general point of view. The bounds are applicable
both for all models with spontaneous R-parity violation and for explicit
bilinear R-parity violation based on general lepton-chargino and
neutrino-neutralino mixings. We find constraints from semileptonic B, D and K
decays, leptonic decays of the mu and tau, electric dipole moments, as well as
bounds for the anomalous magnetic moment of the muon.Comment: 22 page
On the Mixing of the Scalar Mesons , and
Based on a mass matrix describing the mixing of the scalar states
, and , the hadronic decays of the three
states are investigated. Taking into account the two possible assumptions
concerning the mass level order of the bare states
, and in the
scalar sector, and , we obtain the
glueball-quarkonia content of the three states by solving the unlinear
equations. Some predictions about the decays of the three states in two cases
are presented, which can provide a stringent consistency check of the two
assumptions.Comment: revtex 10 pages, 1 eps figur
S_3 and the L=1 Baryons in the Quark Model and the Chiral Quark Model
The S_3 symmetry corresponding to permuting the positions of the quarks
within a baryon allows us to study the 70-plet of L=1 baryons without an
explicit choice for the spatial part of the quark wave functions: given a set
of operators with definite transformation properties under the spin-flavor
group SU(3) x SU(2) and under this S_3, the masses of the baryons can be
expressed in terms of a small number of unknown parameters which are fit to the
observed L=1 baryon mass spectrum. This approach is applied to study both the
quark model and chiral constituent quark model. The latter theory leads to a
set of mass perturbations which more satisfactorily fits the observed L=1
baryon mass spectrum (though we can say nothing, within our approach, about the
physical reasonableness of the parameters in the fit). Predictions for the
mixing angles and the unobserved baryon masses are given for both models as
well as a discussion of specific baryons.Comment: 24 pages, requires picte
Effective String Theory of Vortices and Regge Trajectories
Starting from a field theory containing classical vortex solutions, we obtain
an effective string theory of these vortices as a path integral over the two
transverse degrees of freedom of the string. We carry out a semiclassical
expansion of this effective theory, and use it to obtain corrections to Regge
trajectories due to string fluctuations.Comment: 27 pages, revtex, 3 figures, corrected an error with the cutoff in
appendix E (was previously D), added more discussion of Fig. 3, moved some
material in section 9 to a new appendi
Testing Matter Effects in Very Long Baseline Neutrino Oscillation Experiments
Assuming three-neutrino mixing, we study the capabilities of very long
baseline neutrino oscillation experiments to verify and test the MSW effect and
to measure the lepton mixing angle theta_13. We suppose that intense neutrino
and antineutrino beams will become available in so-called neutrino factories.
We find that the most promising and statistically significant results can be
obtained by studying nu_e ->nu_mu and \bar{nu}_e-> \bar{nu}_mu oscillations
which lead to matter enhancements and suppressions of wrong sign muon rates. We
show the theta_13 ranges where matter effects could be observed as a function
of the baseline. We discuss the scaling laws of rates, significances and
sensitivities with the relevant mixing angles and experimental parameters. Our
analysis includes fluxes, event rates and statistical aspects so that the
conclusions should be useful for the planning of experimental setups. We
discuss the subleading Delta m^2_{21} effects in the case of the LMA MSW
solution of the solar problem, showing that they are small for L >= 7000 km.
For shorter baselines, Delta m^2_{21} effects can be relevant and their
dependence on L offers a further handle for the determination of the
CP-violation phase \delta. Finally we comment on the possibility to measure the
specific distortion of the energy spectrum due to the MSW effect.Comment: 30 pages, 13 figures, figures and more discussion added, results and
conclusions unchange
Coherent and incoherent atomic scattering: Formalism and application to pionium interacting with matter
The experimental determination of the lifetime of pionium provides a very
important test on chiral perturbation theory. This quantity is determined in
the DIRAC experiment at CERN. In the analysis of this experiment, the breakup
probabilities of of pionium in matter are needed to high accuracy as a
theoretical input. We study in detail the influence of the target electrons.
They contribute through screening and incoherent effects. We use Dirac-Hartree-
Fock-Slater wavefunctions in order to determine the corresponding form factors.
We find that the inner-shell electrons contribute less than the weakly bound
outer electrons. Furthermore, we establish a more rigorous estimate for the
magnitude of the contributions form the transverse current (magnetic terms thus
far neglected in the calculations).Comment: Journal of Physics B: Atomic, Molecular and Optical Physics;
(accepted; 22 pages, 6 figures, 26 references) Revised version: more detailed
description of DIRAC experiment; failure of simplest models for incoherent
scattering demonstrated by example
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