7,244 research outputs found
Fibers on a graph with local load sharing
We study a random fiber bundle model with tips of the fibers placed on a
graph having co-ordination number 3. These fibers follow local load sharing
with uniformly distributed threshold strengths of the fibers. We have studied
the critical behaviour of the model numerically using a finite size scaling
method and the mean field critical behaviour is established. The avalanche size
distribution is also found to exhibit a mean field nature in the asymptotic
limit.Comment: 9 pages, 6 figures, To appear in International Journal of Modern
Physics
Quantum Effects in Neural Networks
We develop the statistical mechanics of the Hopfield model in a transverse
field to investigate how quantum fluctuations affect the macroscopic behavior
of neural networks. When the number of embedded patterns is finite, the Trotter
decomposition reduces the problem to that of a random Ising model. It turns out
that the effects of quantum fluctuations on macroscopic variables play the same
roles as those of thermal fluctuations. For an extensive number of embedded
patterns, we apply the replica method to the Trotter-decomposed system. The
result is summarized as a ground-state phase diagram drawn in terms of the
number of patterns per site, , and the strength of the transverse
field, . The phase diagram coincides very accurately with that of the
conventional classical Hopfield model if we replace the temperature T in the
latter model by . Quantum fluctuations are thus concluded to be quite
similar to thermal fluctuations in determination of the macroscopic behavior of
the present model.Comment: 34 pages, LaTeX, 9 PS figures, uses jpsj.st
Nutation versus angular dependent NQR spectroscopy and the impact of underdoping on charge inhomogeneities in YBaCuO
We describe two different nuclear quadrupole resonance (NQR) based
techniques, designed to measure the local asymmetry of the internal electric
field gradient, and the tilt angle of the main NQR principal axis z from the
crystallographic axis c. These techniques use the dependence of the NQR signal
on the duration of the radio frequency (rf) pulse and on the direction of the
rf field H1 with respect to the crystal axis. The techniques are applied to
oriented powder of YBaCuO fully enriched with 63Cu.
Measurements were performed at different frequencies, corresponding to
different in-plane copper sites with respect to the dopant. Combining the
results from both techniques, we conclude that oxygen deficiency in the chain
layer lead to a rotation of the NQR main principal axis at the nearby Cu on the
CuO2 planes by 20+-degrees. This occurs with no change to the asymmetry. The
axis rotation associated with oxygen deficiency means that there must be
electric field inhomogeneities in the CuO2 planes only in the vicinity of the
missing oxygen.Comment: 9 pages, 10 figure
Capacity strengthening in malaria research: the Gates Malaria Partnership.
The Gates Malaria Partnership (GMP) includes five African and four European partner institutions. Its research programme has five priority areas involving an extensive range of field-based studies. GMP research has contributed significantly to the development of new research consortia investigating strategies for improving means of malaria control, and has already had an impact on policy and practice. A substantial investment in innovative training activities in malaria has enhanced knowledge and practice of malaria control at all levels from policy making to local community involvement. Capacity development, notably through a PhD programme, has been an underlying feature of all aspects of the programme
Morbidity Pattern Among Out-Patients Attending Urban Health Training Centre in Srinagar
The current study was designed to identify the morbidity pattern of out-patients attending Urban Health Training Centre in an urban area of a medical college in Srinagar, Pauri Garhwal district, Uttarakhand, North India. The present study record-based retrospective study was conducted among the out-patients attending the regular clinic at the Urban Health Training Centre, of a medical college in Srinagar city of Uttarakhand State of North India during the study period of one year in 2014. Data was retrieved from the OPD registers maintained at the clinic. Data was collected pertaining to socio-demographic profile, morbidity details and treatment pattern. Diseases were identified using the International Classification of Diseases (ICD-10) code. Descriptive analysis was done. During the study period, a total of 9343 subjects attended the OPD. Among them, majority of them (60%) were females. More than half (56 %) belonged to the age group of 35-65 year age-group. The association of disease classification was found to be statistically significant with respect to gender. The leading morbidity of communicable disease was found to be certain infectious and parasitic diseases especially Typhoid whereas musculoskeletal system and connective tissue disorders were the most common cause among morbidity due to NCDs. Out of all, typhoid was found to cause maximum of morbidity among the subjects. The present study highlights the morbidity pattern of communicable and NCDs among the population of hilly areas of Garhwal, Uttarakhand India. Priority should be preferred for the regular tracking of diseases in terms of preventive and promotive aspects. Morbidity in the out- door clinics reflects the emerging trend of mixed disease spectrum burden comprising communicable and non-communicable diseases
Modulation of the local density of states within the -density wave theory in the underdoped cuprates
The low temperature scanning tunneling microscopy spectra in the underdoped
regime is analyzed from the perspective of coexisting -density wave and
d-wave superconducting states. The calculations are carried out in the presence
of a low concentration of unitary impurities and within the framework of the
fully self-consistent Bogoliubov-de Gennes theory, which allows local
modulations of the magnitude of the order parameters in response to the
impurities. Our theory captures the essential aspects of the experiments in the
underdoped BSCCO at very low temperatures.Comment: 4 pages, 4 eps figures, RevTex4. New added material as well as
reference
Charge-Inhomogeneity doping relations in YBCO detected by Angle Dependent Nuclear Quadrupole Resonance
The origin of charge inhomogeneity in YBa_{2}Cu_{3}O_{y} is investigated
using a new experimental method designed to determine the nuclear quadrupole
resonance (NQR) asymmetry parameter eta for very wide NQR lines at different
positions on the line. The method is based on the measurement of the echo
intensity as a function of the angle between the radio frequency field H1 and
the principal axis of the electric field gradient. Static charge inhomogeneity
deduced from eta>0 are found in this compound, but only in conjunction with
oxygen deficiency. This limits considerably the possible forms of charge
inhomogeneity in bulk YBa_{2}Cu_{3}O_{y}.Comment: To be published in Phys. Rev. B; Revised version with a correction to
figure
Hybrid LSTM and Encoder-Decoder Architecture for Detection of Image Forgeries
With advanced image journaling tools, one can easily alter the semantic
meaning of an image by exploiting certain manipulation techniques such as
copy-clone, object splicing, and removal, which mislead the viewers. In
contrast, the identification of these manipulations becomes a very challenging
task as manipulated regions are not visually apparent. This paper proposes a
high-confidence manipulation localization architecture which utilizes
resampling features, Long-Short Term Memory (LSTM) cells, and encoder-decoder
network to segment out manipulated regions from non-manipulated ones.
Resampling features are used to capture artifacts like JPEG quality loss,
upsampling, downsampling, rotation, and shearing. The proposed network exploits
larger receptive fields (spatial maps) and frequency domain correlation to
analyze the discriminative characteristics between manipulated and
non-manipulated regions by incorporating encoder and LSTM network. Finally,
decoder network learns the mapping from low-resolution feature maps to
pixel-wise predictions for image tamper localization. With predicted mask
provided by final layer (softmax) of the proposed architecture, end-to-end
training is performed to learn the network parameters through back-propagation
using ground-truth masks. Furthermore, a large image splicing dataset is
introduced to guide the training process. The proposed method is capable of
localizing image manipulations at pixel level with high precision, which is
demonstrated through rigorous experimentation on three diverse datasets
Sine-Gordon Field Theory for the Kosterlitz-Thouless Transitions on Fluctuating Membranes
In the preceding paper, we derived Coulomb-gas and sine-Gordon Hamiltonians
to describe the Kosterlitz-Thouless transition on a fluctuating surface. These
Hamiltonians contain couplings to Gaussian curvature not found in a rigid flat
surface. In this paper, we derive renormalization-group recursion relations for
the sine-Gordon model using field-theoretic techniques developed to study flat
space problems.Comment: REVTEX, 14 pages with 6 postscript figures compressed using uufiles.
Accepted for publication in Phys. Rev.
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