675 research outputs found
Enhanced Cluster Based Routing Protocol for MANETS
Mobile ad-hoc networks (MANETs) are a set of self organized wireless mobile
nodes that works without any predefined infrastructure. For routing data in
MANETs, the routing protocols relay on mobile wireless nodes. In general, any
routing protocol performance suffers i) with resource constraints and ii) due
to the mobility of the nodes. Due to existing routing challenges in MANETs
clustering based protocols suffers frequently with cluster head failure
problem, which degrades the cluster stability. This paper proposes, Enhanced
CBRP, a schema to improve the cluster stability and in-turn improves the
performance of traditional cluster based routing protocol (CBRP), by electing
better cluster head using weighted clustering algorithm and considering some
crucial routing challenges. Moreover, proposed protocol suggests a secondary
cluster head for each cluster, to increase the stability of the cluster and
implicitly the network infrastructure in case of sudden failure of cluster
head.Comment: 6 page
The Gompertz-Pareto Income Distribution
This work analyzes the Gompertz-Pareto distribution (GPD) of personal income,
formed by the combination of the Gompertz curve, representing the overwhelming
majority of the economically less favorable part of the population of a
country, and the Pareto power law, which describes its tiny richest part.
Equations for the Lorenz curve, Gini coefficient and the percentage share of
the Gompertzian part relative to the total income are all written in this
distribution. We show that only three parameters, determined by linear data
fitting, are required for its complete characterization. Consistency checks are
carried out using income data of Brazil from 1981 to 2007 and they lead to the
conclusion that the GPD is consistent and provides a coherent and simple
analytical tool to describe personal income distribution data.Comment: 13 pages, 5 figures, LaTeX. Accepted for publication in "Physica A
Dipolar degrees of freedom and Isospin equilibration processes in Heavy Ion collisions
Background: In heavy ion collision at the Fermi energies Isospin
equilibration processes occur- ring when nuclei with different charge/mass
asymmetries interacts have been investigated to get information on the
nucleon-nucleon Iso-vectorial effective interaction. Purpose: In this paper,
for the system 48Ca +27 Al at 40 MeV/nucleon, we investigate on this process by
means of an observable tightly linked to isospin equilibration processes and
sensitive in exclusive way to the dynamical stage of the collision. From the
comparison with dynamical model calculations we want also to obtain information
on the Iso-vectorial effective microscopic interaction. Method: The average
time derivative of the total dipole associated to the relative motion of all
emitted charged particles and fragments has been determined from the measured
charges and velocities by using the 4? multi-detector CHIMERA. The average has
been determined for semi- peripheral collisions and for different charges Zb of
the biggest produced fragment. Experimental evidences collected for the systems
27Al+48Ca and 27Al+40Ca at 40 MeV/nucleon used to support this novel method of
investigation are also discussed.Comment: Submitted for publication on Phys. Rev. C. 0n 24-oct-201
Evidence that the Bursting Component of the X-ray Radiation From 3C 111 Originates in the PC-Scale Jet
Evidence is presented indicating that the bursting component of the X-ray
radiation detected in the nuclear region of the active radio galaxy 3C 111
comes from the blobs ejected in the pc-scale jet and not from the accretion
disc. After each new outburst the radio flux density associated with it
increases to a peak in ~1 year and then subsides over a period of 1-2 years
with the flux falling off exponentially as the blob moves outward and
dissipates. Similar peaks (bursts) are seen in the X-ray light curve and a
cross-correlation between the two shows a very high correlation with the X-ray
peaks leading the radio peaks by ~100 days. A second cross-correlation, this
time between the radio event start times and the X-ray light curve, also shows
a significant correlation. When this is taken together with the long (~1 yr)
delay between the start of each ejection event and its associated X-ray peak it
indicates that this bursting component of the X-ray flux must be associated
with the ejected blobs in the pc-scale jet and not with the accretion disc.
Because X-ray telescopes do not have the resolution required to resolve the
accretion disc area from the pc-scale jet, this paper is the first to present
observational evidence that can pinpoint the point of origin of at least those
long-timescale X-ray bursts with durations of 1-3 yrs.Comment: 11 pages, 8 Figures. Accepted for publication in Astrophysics and
Space Scienc
String non(anti)commutativity for Neveu-Schwarz boundary conditions
The appearance of non(anti)commutativity in superstring theory, satisfying
the Neveu-Schwarz boundary conditions is discussed in this paper. Both an open
free superstring and also one moving in a background antisymmetric tensor field
are analyzed to illustrate the point that string non(anti)commutativity is a
consequence of the nontrivial boundary conditions. The method used here is
quite different from several other approaches where boundary conditions were
treated as constraints. An interesting observation of this study is that, one
requires that the bosonic sector satisfies Dirichlet boundary conditions at one
end and Neumann at the other in the case of the bosonic variables
being antiperiodic. The non(anti)commutative structures derived in this paper
also leads to the closure of the super constraint algebra which is essential
for the internal consistency of our analysis.Comment: new references added, original article appeared in Int.J.Theor.Phy
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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