644 research outputs found
Pre-processing Algorithm for Rectification of Geometric Distortions in Satellite Images
A number of algorithms have been reported to process and remove geometric distortions in satellite images. Ortho-correction, geometric error correction, radiometric error removal, etc are a few important examples. These algorithm require supplementary meta-information of the satellite images such as ground control points and correspondence, sensor orientation details, elevation profile of the terrain, etc to establish corresponding transformations. In this paper, a pre-processing algorithm has been proposed which removes systematic distortions of a satellite image and thereby removes the blank portion of the image. It is an input-to-output mapping of image pixels, where the transformation computes the coordinate of each output pixel corresponding to the input pixel of an image. The transformation is established by the exact amount of scaling, rotation and translation needed for each pixel in the input image so that the distortion induced during the recording stage is corrected.Defence Science Journal, 2011, 61(2), pp.174-179, DOI:http://dx.doi.org/10.14429/dsj.61.42
Canonical steering ellipsoids of pure symmetric multiqubit states with two distinct spinors and volume monogamy of steering
Quantum steering ellipsoid formalism provides a faithful representation of
all two-qubit states and helps in obtaining correlation properties of the state
through the steering ellipsoid. The steering ellipsoids corresponding to the
two-qubit subsystems of permutation symmetric -qubit states is analysed
here. The steering ellipsoids of two-qubit states that have undergone local
operations on both the qubits so as to bring the state to its canonical form
are the so-called canonical steering ellipsoids. We construct and analyze the
geometric features of the canonical steering ellipsoids corresponding to pure
permutation symmetric -qubit states with two distinct spinors. Depending on
the degeneracy of the two spinors in the pure symmetric -qubit state, there
arise several families which cannot be converted into one another through
Stochastic Local Operations and Classical Communications (SLOCC). The canonical
steering ellipsoids of the two-qubit states drawn from the pure symmetric
-qubit states with two distinct spinors allow for a geometric visualization
of the SLOCC-inequivalent class of states. We show that the states belonging to
the W-class correspond to oblate spheroid centered at with
fixed semiaxes lengths and . The states belonging to
all other SLOCC inequivalent families correspond to ellipsoids centered at the
origin of the Bloch sphere. We also explore volume monogamy relations of states
belonging to these families, mainly the W-class of states.Comment: 13 pages, 13 figures; Revised version; Comments welcom
Optical absorption and photoluminescence spectroscopy of the growth of silver nanoparticles
Results obtained from the optical absorption and photoluminescence (PL)
spectroscopy experiments have shown the formation of excitons in the
silver-exchanged glass samples. These findings are reported here for the first
time. Further, we investigate the dramatic changes in the photoemission
properties of the silver-exchanged glass samples as a function of postannealing
temperature. Observed changes are thought to be due to the structural
rearrangements of silver and oxygen bonding during the heat treatments of the
glass matrix. In fact, photoelectron spectroscopy does reveal these chemical
transformations of silver-exchanged soda glass samples caused by the thermal
effects of annealing in a high vacuum atmosphere. An important correlation
between temperature-induced changes of the PL intensity and thermal growth of
the silver nanoparticles has been established in this Letter through precise
spectroscopic studies.Comment: 15 pages,4 figures,PDF fil
Quantum Hamilton-Jacobi analysis of PT symmetric Hamiltonians
We apply the quantum Hamilton-Jacobi formalism, naturally defined in the
complex domain, to a number of complex Hamiltonians, characterized by discrete
parity and time reversal (PT) symmetries and obtain their eigenvalues and
eigenfunctions. Examples of both quasi-exactly and exactly solvable potentials
are analyzed and the subtle differences, in the singularity structures of their
quantum momentum functions, are pointed out. The role of the PT symmetry in the
complex domain is also illustrated.Comment: 11 page
Block Least-Mean Squares Algorithm Over Distributed Wireless Sensor Network
In a distributed parameter estimation problem, during each sampling instant, a typical sensor node communicates its estimate either by the diffusion algorithm or by the incremental algorithm. Both these conventional distributed algorithms involve significant communication overheads and, consequently, defeat the basic purpose of wireless sensor networks. In the present paper, we therefore propose two new distributed algorithms, namely, block diffusion least mean square (BDLMS) and block incremental least mean square (BILMS) by extending the concept of block adaptive filtering techniques to the distributed adaptation scenario. The performance analysis of the proposed BDLMS and BILMS algorithms has been carried out and found to have similar performances to those offered by conventional diffusion LMS and incremental LMS algorithms, respectively. The convergence analyses of the proposed algorithms obtained from the simulation study are also found to be in agreement with the theoretical analysis. The remarkable and interesting aspect of the proposed block-based algorithms is that their communication overheads per node and latencies are less than those of the conventional algorithms by a factor as high as the block size used in the algorithms
Laughlin Wave Function and One-Dimensional Free Fermions
Making use of the well-known phase space reduction in the lowest Landau
level(LLL), we show that the Laughlin wave function for the
case can be obtained exactly as a coherent state representation of an one
dimensional wave function. The system consists of copies of
free fermions associated with each of the electrons, confined in a common
harmonic well potential. Interestingly, the condition for this exact
correspondence is found to incorporate Jain's parton picture. We argue that,
this correspondence between the free fermions and quantum Hall effect is due to
the mapping of the system under consideration, to the Gaussian unitary
ensemble in the random matrix theory.Comment: 7 pages, Latex , no figure
Evaluation of gastrointestinal helminths in canine population of Bhubaneswar, Odisha, India: a public health appraisal
Aim: To evaluate the presence of gastrointestinal helminthic parasites in clinically apparent canines of Bhubaneswar, Odisha and to determine the risk of zoonotic infection to dog owners through questionnaire survey.
Materials and Methods: A total of 154 dogs, with clinical signs of gastroenteritis were examined for the presence of helminthic ova and /or larvae in their faecal sample by direct smear and/ or floatation and centrifugation method. Prevalence was determined by sex wise, age wise, and breed wise. A structured questionnaire on 50 dog owners was designed to gather information on dog ownership, management and related risks on public health.
Results: In the present investigation, the overall prevalence of gastrointestinal helminths infection was 41.46%. The infection rate was highest for mixed parasitic infection (26.57%) followed by Ancylostoma caninum (23.44%), Toxocara canis (20.31%) and lowest for Taenia spp. (3.13%). In relation to different groups, the prevalence was higher in male than female, highest in younger animals and it was shown a decreasing trend as age increased. It was also higher in non-descriptive breeds than pure and exotic breeds. Very few dog owners (10%) were conscious about that canine parasite could be transmitted to humans but none of them could provide correct information on the mode of transmission. Only 12 % dog owners had maintained standard deworming schedule.
Conclusion: The findings showed that the high levels of ignorance among dog owners about canine helminthic parasites and transmission coupled with significant infection rates among the dogs in the community warrants immediate action needs to be taken to decrease infection rate in dogs and to raise awareness among the community about zoonotic diseases
Blue luminescence of Au nanoclusters embedded in silica matrix
Photoluminescence study using the 325 nm He-Cd excitation is reported for the
Au nanoclusters embedded in SiO2 matrix. Au clusters are grown by ion beam
mixing with 100 KeV Ar+ irradiation on Au [40 nm]/SiO2 at various fluences and
subsequent annealing at high temperature. The blue bands above ~3 eV match
closely with reported values for colloidal Au nanoclusters and supported Au
nanoislands. Radiative recombination of sp electrons above Fermi level to
occupied d-band holes are assigned for observed luminescence peaks. Peaks at
3.1 eV and 3.4 eV are correlated to energy gaps at the X- and L-symmetry
points, respectively, with possible involvement of relaxation mechanism. The
blue shift of peak positions at 3.4 eV with decreasing cluster size is reported
to be due to the compressive strain in small clusters. A first principle
calculation based on density functional theory using the full potential linear
augmented plane wave plus local orbitals (FP-LAPW+LO) formalism with
generalized gradient approximation (GGA) for the exchange correlation energy is
used to estimate the band gaps at the X- and L-symmetry points by calculating
the band structures and joint density of states (JDOS) for different strain
values in order to explain the blueshift of ~0.1 eV with decreasing cluster
size around L-symmetry point.Comment: 13 pages, 7 Figures Only in PDF format; To be published in J. of
Chem. Phys. (Tentative issue of publication 8th December 2004
Analytic calculations of trial wave functions of the fractional quantum Hall effect on the sphere
We present a framework for the analytic calculations of the hierarchical wave
functions and the composite fermion wave functions in the fractional quantum
Hall effect on the sphere by using projective coordinates. Then we calculate
the overlaps between these two wave functions at various fillings and small
numbers of electrons. We find that the overlaps are all most equal to one. This
gives a further evidence that two theories of the fractional quantum Hall
effect, the hierarchical theory and the composite fermion theory, are
physically equivalent.Comment: 37 pages, revte
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