598 research outputs found
The κ - μ shadowed fading model with arbitrary intercluster correlation
In this paper, we propose a generalization of the
well-known κ-μ shadowed fading model. Based on the clustering
of multipath waves as the baseline model, the novelty of this
new distribution is the addition of an arbitrary correlation for
the scattered components within each cluster. It also inherits
the random fluctuation of the dominant component, which is
assumed to be the same for all clusters. Thus, it unifies a wide
variety of models: Rayleigh, Rician, Rician shadowed, Nakagami-
m, κ-μ and κ-μ shadowed as well as multivariate Rayleigh,
Rician and Rician shadowed. The main statistics of the newly
proposed model, i.e. moment generating function, probability
density function and cumulative density function, are given in
terms of exponentials and powers, and some numerical results
are provided in order to analyze the impact of the arbitrary
intercluster correlation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Preface : (Boundary Element Method) Computers and Structures 83 (2005)
The Boundary Element Method is a powerful numerical technique well rooted in everyday engineering practice. This is shown by boundary element methods included in the most important commercial computer packages and in the continuous publication of books composed to explain the features of the method to beginners or practicing engineers. Our first paper in Computers & Structures on Boundary Elements was published in 1979 (C & S 10, pp. 351–362), so this Special Issue is for us not only the accomplishment of our obligation to show other colleagues the possibilities of a numerical technique in which we believe, but also the celebration of our particular silver jubilee with this Journal
A Tractable Product Channel Model for Line-of-Sight Scenarios
We present a general and tractable fading model for line-of-sight (LOS)
scenarios, which is based on the product of two independent and non-identically
distributed - shadowed random variables. Simple closed-form
expressions for the probability density function, cumulative distribution
function and moment-generating function are derived, which are as tractable as
the corresponding expressions derived from a product of Nakagami- random
variables. This model simplifies the challenging characterization of LOS
product channels, as well as combinations of LOS channels with non-LOS ones. We
leverage these results to analyze performance measures of interest in the
contexts of wireless powered and backscatter communications, where both forward
and reverse links are inherently of LOS nature, as well as in device-to-device
communications subject to composite fading. In these contexts, the model shows
a higher flexibility when fitting field measurements with respect to
conventional approaches based on product distributions with deterministic LOS,
together with a more complete physical interpretation of the underlying
propagation characteristics.Comment: This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
A Comprehensive Analysis of 5G Heterogeneous Cellular Systems operating over - Shadowed Fading Channels
Emerging cellular technologies such as those proposed for use in 5G
communications will accommodate a wide range of usage scenarios with diverse
link requirements. This will include the necessity to operate over a versatile
set of wireless channels ranging from indoor to outdoor, from line-of-sight
(LOS) to non-LOS, and from circularly symmetric scattering to environments
which promote the clustering of scattered multipath waves. Unfortunately, many
of the conventional fading models adopted in the literature to develop network
models lack the flexibility to account for such disparate signal propagation
mechanisms. To bridge the gap between theory and practical channels, we
consider - shadowed fading, which contains as special cases, the
majority of the linear fading models proposed in the open literature, including
Rayleigh, Rician, Nakagami-m, Nakagami-q, One-sided Gaussian, -,
-, and Rician shadowed to name but a few. In particular, we apply an
orthogonal expansion to represent the - shadowed fading
distribution as a simplified series expression. Then using the series
expressions with stochastic geometry, we propose an analytic framework to
evaluate the average of an arbitrary function of the SINR over -
shadowed fading channels. Using the proposed method, we evaluate the spectral
efficiency, moments of the SINR, bit error probability and outage probability
of a -tier HetNet with classes of BSs, differing in terms of the
transmit power, BS density, shadowing characteristics and small-scale fading.
Building upon these results, we provide important new insights into the network
performance of these emerging wireless applications while considering a diverse
range of fading conditions and link qualities
Functions of S-nitrosylation in plant hormone networks
In plants, a wide frame of physiological processes are regulated in liaison by both, nitric oxide (NO) and hormones. Such overlapping roles raise the question of how the cross-talk between NO and hormones trigger common physiological responses. In general, NO has been largely accepted as a signaling molecule that works in different processes. Among the most relevant ways NO and the NO-derived reactive species can accomplish their biological functions it is worthy to mention post-translational protein modifications. In the last years, S-nitrosylation has been the most studied NO-dependent regulatory mechanism. Briefly, S-nitrosylation is a redox-based mechanism for cysteine residue modification and is being recognized as a ubiquitous regulatory reaction comparable to phosphorylation. Therefore, it is emerging as a crucial mechanism for the transduction of NO bioactivity in plants and animals. In this mini-review, we provide an overview on S-nitrosylation of target proteins related to hormone networks in plants.Fil: Paris, Ramiro. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Biológicas; ArgentinaFil: Iglesias, María José. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Biológicas; ArgentinaFil: Terrile, Maria Cecilia. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Biológicas; ArgentinaFil: Casalongue, Claudia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Biológicas; Argentin
A Unifying Statistical Model for Atmospheric Optical Scintillation
In this paper we develop a new statistical model for the irradiance
fluctuations of an unbounded optical wavefront (plane and spherical waves)
propagating through a turbulent medium under all irradiance fluctuation
conditions in homogeneous, isotropic turbulence. The major advantage of the
model is that leads to closed-form and mathematically-tractable expressions for
the fundamental channel statistics of an unbounded optical wavefront under all
turbulent regimes. Furthermore, it unifies most of the proposed statistical
models for the irradiance fluctuations derived in the bibliography providing,
in addition, an excellent agreement with the experimental data.Comment: An extended version of this paper has been submitted and
provisionally accepted for publication in the book under the working title
"Numerical Simulations / Book 2", Ed. Intech, ISBN 978-953-307-1423-
Energy Resource Scheduling Optimization for Smart Power Distribution Grids - Hour-Ahead Horizon
As the use of renewable energy sources grows, the energy aggregator company plays an increasingly significant role in ensuring extremely flexible supply and demand, as requested by the smart grid architecture. This study presents a model for the problem of intraday energy resource scheduling (hour-ahead). The model is solved using the CPLEX solver and is developed as mixed integer linear programming. A distribution network with 180 buses located in Portugal considering high distributed energy resources penetration is used to demonstrate the application of the proposed model. The findings indicate how forecast errors and contractual restrictions with energy storage systems and electric car charging stations affect hour-ahead scheduling costs.This research has received funding from FEDER funds through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020) and National Funds through the FCT Portuguese Foundation for Science and Technology, under Projects PTDC/EEI-EEE/28983/2017 (CENER-GETIC), CEECIND/02814/2017 (Joao Soares grant), and UIDB/000760/2020.info:eu-repo/semantics/publishedVersio
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