1,633 research outputs found
Heterogeneous V2V Communications in Multi-Link and Multi-RAT Vehicular Networks
Connected and automated vehicles will enable advanced traffic safety and
efficiency applications thanks to the dynamic exchange of information between
vehicles, and between vehicles and infrastructure nodes. Connected vehicles can
utilize IEEE 802.11p for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure
(V2I) communications. However, a widespread deployment of connected vehicles
and the introduction of connected automated driving applications will notably
increase the bandwidth and scalability requirements of vehicular networks. This
paper proposes to address these challenges through the adoption of
heterogeneous V2V communications in multi-link and multi-RAT vehicular
networks. In particular, the paper proposes the first distributed (and
decentralized) context-aware heterogeneous V2V communications algorithm that is
technology and application agnostic, and that allows each vehicle to
autonomously and dynamically select its communications technology taking into
account its application requirements and the communication context conditions.
This study demonstrates the potential of heterogeneous V2V communications, and
the capability of the proposed algorithm to satisfy the vehicles' application
requirements while approaching the estimated upper bound network capacity
Bohr's equivalence relation in the space of Besicovitch almost periodic functions
Based on Bohr's equivalence relation which was established for general
Dirichlet series, in this paper we introduce a new equivalence relation on the
space of almost periodic functions in the sense of Besicovitch,
, defined in terms of polynomial approximations. From
this, we show that in an important subspace , where Parseval's equality and Riesz-Fischer theorem
holds, its equivalence classes are sequentially compact and the family of
translates of a function belonging to this subspace is dense in its own class.Comment: Because of a mistake detected in one of the references, the
equivalence relation which is inspired by that of Bohr is revised to adapt
correctly the situation in the general case. arXiv admin note: text overlap
with arXiv:1801.0803
A generalization of Bohr's Equivalence Theorem
Based on a generalization of Bohr's equivalence relation for general
Dirichlet series, in this paper we study the sets of values taken by certain
classes of equivalent almost periodic functions in their strips of almost
periodicity. In fact, the main result of this paper consists of a result like
Bohr's equivalence theorem extended to the case of these functions.Comment: Because of a mistake detected in one of the references, the previous
version of this paper has been modified by the authors to restrict the scope
of its application to the case of existence of an integral basi
On some solutions of a functional equation related to the partial sums of the Riemann zeta function
In this paper, we prove that infinite-dimensional vector spaces of α-dense curves are generated by means of the functional equations f(x)+f(2x)+⋯+f(nx)=0, with n≥2, which are related to the partial sums of the Riemann zeta function. These curves α-densify a large class of compact sets of the plane for arbitrary small α, extending the known result that this holds for the cases n=2,3. Finally, we prove the existence of a family of solutions of such functional equation which has the property of quadrature in the compact that densifies, that is, the product of the length of the curve by the nth power of the density approaches the Jordan content of the compact set which the curve densifies.The author was partially supported by Vicerrectorado de Investigación, Desarrollo e Innovación de la Universidad de Alicante under project GRE11-23
Analytical Models of the Performance of C-V2X Mode 4 Vehicular Communications
The C-V2X or LTE-V standard has been designed to support V2X (Vehicle to
Everything) communications. The standard is an evolution of LTE, and it has
been published by the 3GPP in Release 14. This new standard introduces the
C-V2X or LTE-V Mode 4 that is specifically designed for V2V communications
using the PC5 sidelink interface without any cellular infrastructure support.
In Mode 4, vehicles autonomously select and manage their radio resources. Mode
4 is highly relevant since V2V safety applications cannot depend on the
availability of infrastructure-based cellular coverage. This paper presents the
first analytical models of the communication performance of C-V2X or LTE-V Mode
4. In particular, the paper presents analytical models for the average PDR
(Packet Delivery Ratio) as a function of the distance between transmitter and
receiver, and for the four different types of transmission errors that can be
encountered in C-V2X Mode 4. The models are validated for a wide range of
transmission parameters and traffic densities. To this aim, this study compares
the results obtained with the analytical models to those obtained with a C-V2X
Mode 4 simulator implemented over Veins
Vida en el Universo ¿Regla o excepción?
Nuestro planeta Tierra es hoy el único lugar conocido que alberga vida. La posible existencia de vida extraterrestre es una cuestión que ha fascinado a la humanidad durante siglos. Desde el punto de vista cientÃfico, obtener una respuesta requiere un enorme esfuerzo colaborativo entre múltiples campos de investigación cientÃfica que incluyen astronomÃa, fÃsica, quÃmica, biologÃa, geologÃa, e incluso filosofÃa de la ciencia. Lejos de ser exhaustivo, el presente dossier expone diferentes piezas del enorme rompecabezas que es la astrobiologÃa, desde la exploración de nuestro Sistema Solar hasta el de los exoplanetas (planetas orbitando alrededor de otras estrellas). El dossier subraya el importante papel que juega la investigación europea para conseguir el nivel de conocimiento que poseemos, incluyendo un artÃculo entero dedicado a la misión espacial JUICE, de la ESA (European Space Agency), como ejemplo ilustrativo. El último artÃculo aborda áreas más imaginativas que describen la conexión que existe entre la música y la exploración del cosmos, mostrando que la astronomÃa y el arte van muy frecuentemente de la mano
On the Result of Invariance of the Closure Set of the Real Projections of the Zeros of an Important Class of Exponential Polynomials
In this paper we provide the proof of a practical point-wise characterization of the set RP defined by the closure set of the real projections of the zeros of an exponential polynomial P(z) = Σn j=1 cjewjz with real frequencies wj linearly independent over the rationals. As a consequence, we give a complete description of the set RP and prove its invariance with respect to the moduli of the c′ js, which allows us to determine exactly the gaps of RP and the extremes of the critical interval of P(z) by solving inequations with positive real numbers. Finally, we analyse the converse of this result of invariance.The research was partially supported by Generalitat Valenciana under Project GV/2015/035
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