37,624 research outputs found
Analysis of neighbour and isolated node of intersection area based geocasting protocol (IBGP) in VANET
Geocasting is a special variant of multicasting, where data packet or message
is transmitted to a predefined geographical location i.e., known as geocast
region. The applications of geocasting in VANET are to disseminate information
like, collision warning, advertising, alerts message, etc. In this paper, we
have proposed a model for highway scenario where the highway is divided into
number of cells. The intersection area between two successive cells is computed
to find the number of common nodes. Therefore, probabilistic analysis of the
nodes present and void occurrence in the intersection area is carried out.
Further, we have defined different forwarding zones to restrict the number of
participated nodes for data delivery. Number of nodes present and void
occurrence in the different forwarding zones have also been analysed based on
various node density in the network to determine the successful delivery of
data. Our analytical results show that in a densely populated network, data can
be transmitted with low radio transmission range. In a densely populated
network smaller forwarding zones will be selected for data delivery
A Performance Analysis of LAR Protocol for Vehicular Ad Hoc Networks in City Scenarios
In this paper, performance analysis of Location Aided Routing (LAR) protocol
in different city scenarios has been done. The mobility model considered is
Manhattan model. This mobility model used to emulate the movement pattern of
nodes i.e., vehicles on streets defined by maps. Our objective is to provide a
qualitative analysis of the LAR protocol in different city scenarios in
Vehicular Ad hoc Networks. We have considered three different city scenarios
for the analysis of the protocol. The simulation work has been conducted using
the Glomosim 2.03 simulator. The results show that LAR1 protocol achieves
maximum packet delivery ratio is 99.68 % and maximum average end-to-end delay
is 7.319969 ms when the network is sparsely populated. Further, for densely
populated network maximum achieved packet delivery ratio is 87.58% and average
end-to-end delay is 0.017684 ms
RMS and charge radii in a potential model
The Dalgarno's method of perturbation is used to solve the Schrodinger's
equation with the Cornell potential . The
short range and long range effect of the potential is incorporated in the same
wave function by using two scales and as an integration limit. The
results for bounds on r.m.s. radii of various heavy flavored mesons are
reported. We have also showed the relation between r.m.s. and charge radius of
mesons.Comment: 10 pages, 3 tables in Indian Journal of Physics (2016
Isgur-Wise function and a new approach to Potential Model
Considering the Cornell potential , we have
revisited the Dalgarno's method of perturbation by incorporating two scales
and as integration limit so that the perturbative
procedure can be improved in a potential model. With the improved version of
the wave function the ground state masses of the heavy-light mesons and are computed. The slopes and curvatures of the form factors
of semi-leptonic decays of heavy-light mesons in both HQET limit and finite
mass limit are calculated and compared with the available data.Comment: 18 pages, 2 figures, To appear in International Journal of Modern
Physics
Study of resonance states of Be with isospectral bound state microscopic potential
The theoretical procedure of supersymmetric quantum mechanics (SQM) is
adopted for the first time to study quasi-bound states of a weakly bound
nuclear system using microscopic potential. The density dependent M3Y (DDM3Y)
effective interaction was found earlier to give a satisfactory description of
radioactivity, nuclear matter and scattering. In the present work, we have
generated a two-body potential microscopically in a single folding model using
the DDM3Y effective interaction. From this potential, SQM generated a family of
isospectral potentials for Be (Be + n). We investigated the
5/2, 3/2 and 3/2 resonance states of Be. The experimental
data and the present calculations of excitation energies of the above resonance
states are found to be in good agreement.Comment: 7 pages, 6 figure
A Kondo route to spin inhomogeneities in the honeycomb Kitaev model
Paramagnetic impurities in a quantum spin-liquid can result in Kondo effects
with highly unusual properties. We have studied the effect of locally
exchange-coupling a paramagnetic impurity with the spin-1/2 honeycomb Kitaev
model in its gapless spin-liquid phase. The (impurity) scaling equations are
found to be insensitive to the sign of the coupling. The weak and strong
coupling fixed points are stable, with the latter corresponding to a
noninteracting vacancy and an interacting, spin-1 defect for the
antiferromagnetic and ferromagnetic cases respectively. The ground state in the
strong coupling limit in both cases has a nontrivial topology associated with a
finite Z2 flux at the impurity site. For the antiferromagnetic case, this
result can be obtained straightforwardly owing to the integrability of the
Kitaev model with a vacancy. The strong-coupling limit of the ferromagnetic
case is however nonintegrable, and we address this problem through
exact-diagonalization calculations with finite Kitaev fragments. Our exact
diagonalization calculations indicate that that the weak to strong coupling
transition and the topological phase transition occur rather close to each
other and are possibly coincident. We also find an intriguing similarity
between the magnetic response of the defect and the impurity susceptibility in
the two-channel Kondo problem.Comment: 9 pages, 4 figures, revtex4-
Magnetoresistive property study of direct and indirect band gap thermoelectric Bi-Sb alloys
We report magnetoresistive properties of direct and indirect band gap
Bismuth-Antimony (Bi-Sb) alloys. Band gap increases with magnetic field. Large
positive magnetoresistance (MR) approaching to 400 % is observed. Low field MR
experiences quadratic growth and at high field it follows a nearly linear
behavior without sign of saturation. Carrier mobility extracted from low field
MR data, depicts remarkable high value. Correlation between MR and mobility is
revealed. We demonstrate that the strong nearly linear MR at high field can be
well understood by classical method, co-build by Parish and Littlewood.Comment: To be published in Applied Physics Letter
Effect of node mobility on AOMDV protocol in MANET
In this paper, we have analyzed the effect of node mobility on the
performance of AOMDV multipath routing protocol. This routing protocol in ad
hoc network has been analyzed with random way point mobility model only. This
is not sufficient to evaluate the behavior of a routing protocol. Therefore, in
this paper, we have considered Random waypoint, Random Direction and
Probabilistic Random Walk mobility Model for performance analysis of AOMDV
protocol. The result reveals that packet delivery ratio decreases with the
increasing node mobility for all mobility models. Also, average end-to-end
delay is also vary with varying node speed, initially upto 20 nodes in all
mobility models delay is minimum.Comment: 9 pages, 6 figures, International Journal of Wireless & Mobile
Networks (IJWMN) Vol. 6, No. 3, June 201
Imaging polarimetry of the Bok globule CB56
The measurement of polarization of the background stars in the region of Bok
globules is important to study the magnetic field geometry and dust grain
characteristics in the globule. These parameters are important for the
formation and evolution of dark clouds. We made polarimetric observations of
Bok globule CB56 in the R-filter from the 2-metre telescope at IUCAA Girawali
Observatory (IGO). The observations were carried out on 2011 March 4th and 5th.
The CCD images obtained from the instrument (IFOSC) were analyzed, to produce
the polarization map of the Bok globule CB56.Comment: 7 pages, 1 figure, 4 tables; To appear in the Bulletin of the
Astronomical Society of India (BASI) in the June 2012 issu
Correlation Trends in the Hyperfine Structures of Fr
We demonstrate the importance of electron correlation effects in the
hyperfine structure constants of many low-lying states in Fr and
Fr. This is achieved by calculating the magnetic dipole and electric
quadrupole hyperfine structure constants using the Dirac-Fock approximation,
second order many-body perturbation theory and the coupled-cluster method in
the singles and doubles approximation in the relativistic framework. By
combining our recommended theoretical results with the corresponding
experimental values, improved nuclear magnetic dipole and electric quadrupole
moments of the above isotopes are determined. In the present work, it is
observed that there are large discrepancies between the hyperfine structure
constants of the state obtained from the experimental and
theoretical studies whereas good agreements are found for the other
states. Our estimated hyperfine constants for the , , and
states could be very useful as benchmarks for the measurement of these
quantities.Comment: 10 pages, 8 table
- …