900,039 research outputs found
Predictions on the transverse momentum spectra for charged particle production at LHC-energies from a two component model
Transverse momentum spectra, d2σ/(dηdpT2) , of charged hadron production in pp -collisions are considered in terms of a recently introduced two component model. The shapes of the particle distributions vary as a function of the c.m.s. energy in the collision and the measured pseudorapidity interval. As a result the pseudorapidity of a secondary hadron in the moving proton rest frame is shown to be a universal parameter describing the shape of the spectra in pp -collisions. In order to extract predictions on the double-differential cross sections d2σ/(dηdpT2) of hadron production for future LHC-measurements the different sets of available experimental data have been used in this study
Multi-Path Routing and Wavelength Assignment (RWA) Algorithm for WDM Based Optical Networks
In optical WDM networks, transmission of information along optical lines is
advantageous since it has high transmission capacity, scalability, feasibility
and also high reliability. But large amount of information is being carried;
any problem during transmission can lead to severe damage to the data being
carried. Hence it is essential to consider the routing as well as the
wavelength assignment problems and then develop a combined solution for both
the problems. In this paper, we propose to develop a routing and wavelength
assignment algorithm for selecting the suitable alternate path for the data
packets transmission. Two stages are based on the available bandwidth and the
number of wavelength used in the link as construction of alternate paths, route
and wavelength selection. In proposed work, Adaptive Routing and First-Fit
Wavelength Assignment (AR-FFWA) algorithm to be used. For each pair of source
and destination, the path with the minimum granularity values are selected as
the primary path for data transmission, allocating the sufficient wavelength
and the performances will be evaluated by using ns-2 simulation models. When we
compared to existing system the overall blocking probability will be reduced to
too low.Comment: 6 page
Analysis of two transmission eigenvalue problems with a coated boundary condition
In this paper, we investigate two transmission eigenvalue problems associated
with the scattering of a media with a coated boundary. In recent years, there
has been a lot of interest in studying these eigenvalue problems. It can be
shown that the eigenvalues can be recovered from the scattering data and hold
information about the material properties of the media one wishes to determine.
Motivated by recent works we will study the electromagnetic transmission
eigenvalue problem and scalar `zero-index' transmission eigenvalue problem for
a media with a coated boundary. Existence of infinitely many real eigenvalues
will be proven as well as showing that the eigenvalues depend monotonically on
the refractive index and boundary parameter. Numerical examples in two spatial
dimensions are presented for the scalar `zero-index' transmission eigenvalue
problem. Also, in our investigation we prove that as the boundary parameter
tends to zero and infinity we recover the classical eigenvalue problems
Supplement to: Code Spectrum and Reliability Function: Binary Symmetric Channel
A much simpler proof of Theorem 1 from M.Burnashev "Code spectrum and
reliability function: Binary symmetric channel" is presented.Comment: to appear in Problems of Information Transmission, 2007, v. 43, no.
On Reliability Function Of BSC: Expanding The Region, Where It Is Known Exactly
The region of rates ("straight-line"), where the BSC reliability function is
known exactly, is expanded.Comment: Published in Problems of Information Transmission, vol. 51, no. 4,
pp. 3-22, 201
Secure Beamforming in Full-Duplex SWIPT Systems
Physical layer security is a key issue in the full duplex (FD) communication
systems due to the broadcast nature of wireless channels. In this paper, the
joint design of information and artificial noise beamforming vectors is
proposed for the FD simultaneous wireless information and power transferring
(FD-SWIPT) systems. To guarantee high security and energy harvesting
performance of the FD-SWIPT system, the proposed design is formulated as a sum
information transmission rate (SITR) maximization problem under
information-leakage and energy constraints. In addition, we consider the
fairness issue between the uplink and downlink information transmission rates
by formulating a \mbox{fairness-aware} SITR-maximization problem. Although the
formulated \mbox{SITR-maximization} and \mbox{fairness-aware}
\mbox{SITR-maximization} problems are non-convex, we solve them via
semidefinite relaxation and one-dimensional search. The optimality of our
proposed algorithms is theoretically proved, and the computation complexities
are established. Moreover, we propose two suboptimal solutions to the
formulated optimization problems. In terms of the SITR-maximization problem,
numerical results show that the performance achieved by one of the two
suboptimal algorithms is close to the performance of the optimal algorithm with
increasing maximum transmission power of the FD-BST.Comment: submitted for journal publicatio
Metabolically Efficient Information Processing
Energy efficient information transmission may be relevant to biological
sensory signal processing as well as to low power electronic devices. We
explore its consequences in two different regimes. In an ``immediate'' regime,
we argue that the information rate should be maximized subject to a power
constraint, while in an ``exploratory'' regime, the transmission rate per power
cost should be maximized. In the absence of noise, discrete inputs are
optimally encoded into Boltzmann distributed output symbols. In the exploratory
regime, the partition function of this distribution is numerically equal to 1.
The structure of the optimal code is strongly affected by noise in the
transmission channel. The Arimoto-Blahut algorithm, generalized for cost
constraints, can be used to derive and interpret the distribution of symbols
for optimal energy efficient coding in the presence of noise. We outline the
possibilities and problems in extending our results to information coding and
transmission in neurobiological systems.Comment: LaTeX, 15 pages, 4 separate Postscript figure
On Reliability Function of Gaussian Channel with Noisy Feedback: Zero Transmission Rate
For information transmission a discrete time channel with independent
additive Gaussian noise is used. There is also feedback channel with
independent additive Gaussian noise, and the transmitter observes without delay
all outputs of the forward channel via that feedback channel. Transmission of
nonexponential number of messages is considered and the achievable decoding
error exponent for such a combination of channels is investigated. It is shown
that for any finite noise in the feedback channel the achievable error exponent
is better than similar error exponent of the no-feedback channel. Method of
transmission/decoding used in the paper strengthens the earlier method used by
authors for BSC. In particular, for small feedback noise, it allows to get the
gain of 23.6% (instead of 14.3% earlier for BSC).Comment: Published in Problems of Information Transmission, vol. 48, no. 3,
pp. 3--23, 201
Energy Efficiency of Distributed Antenna Systems with Wireless Power Transfer
In this paper, we study energy-efficient resource allocation in distributed
antenna system (DAS) with wireless power transfer, where time-division multiple
access (TDMA) is adopted for downlink multiuser information transmission. In
particular, when a user is scheduled to receive information, other users
harvest energy at the same time using the same radio-frequency (RF) signal. We
consider two types of energy efficiency (EE) metrics: user-centric EE (UC-EE)
and network-centric EE (NC-EE). Our goal is to maximize the UC-EE and NC-EE,
respectively, by optimizing the transmission time and power subject to the
energy harvesting requirements of the users. For both UC-EE and NC-EE
maximization problems, we transform the nonconvex problems into equivalently
tractable problems by using suitable mathematical tools and then develop
iterative algorithms to find the globally optimal solutions. Simulation results
demonstrate the superiority of the proposed methods compared with the benchmark
schemes.Comment: This paper has been already accepted by IEEE Journal on Selected
Areas in Communication
Asynchronous Consensus in Continuous-Time Multi-Agent Systems With Switching Topology and Time-Varying Delays
In this paper, we study asynchronous consensus problems of continuous-time
multi-agent systems with discontinuous information transmission. The proposed
consensus control strategy is implemented only based on the state information
at some discrete times of each agent's neighbors. The asynchronization means
that each agent's update times, at which the agent adjusts its dynamics, are
independent of others'. Furthermore, it is assumed that the communication
topology among agents is time-dependent and the information transmission is
with bounded time-varying delays. If the union of the communication topology
across any time interval with some given length contains a spanning tree, the
consensus problem is shown to be solvable. The analysis tool developed in this
paper is based on the nonnegative matrix theory and graph theory. The main
contribution of this paper is to provide a valid distributed consensus
algorithm that overcomes the difficulties caused by unreliable communication
channels, such as intermittent information transmission, switching
communication topology, and time-varying communication delays, and therefore
has its obvious practical applications. Simulation examples are provided to
demonstrate the effectiveness of our theoretical results.Comment: Regular pape
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