336 research outputs found
Monotone properties of random geometric graphs have sharp thresholds
Random geometric graphs result from taking uniformly distributed points
in the unit cube, , and connecting two points if their Euclidean
distance is at most , for some prescribed . We show that monotone
properties for this class of graphs have sharp thresholds by reducing the
problem to bounding the bottleneck matching on two sets of points
distributed uniformly in . We present upper bounds on the threshold
width, and show that our bound is sharp for and at most a sublogarithmic
factor away for . Interestingly, the threshold width is much sharper for
random geometric graphs than for Bernoulli random graphs. Further, a random
geometric graph is shown to be a subgraph, with high probability, of another
independently drawn random geometric graph with a slightly larger radius; this
property is shown to have no analogue for Bernoulli random graphs.Comment: Published at http://dx.doi.org/10.1214/105051605000000575 in the
Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute
of Mathematical Statistics (http://www.imstat.org
Biligiri Tiger reserve: include Soligas in conservation plan
Protesting against the proposal of the Karnataka forest department to notify the Biligiri Hills as a Tiger Reserve, the resident Soliga adivasis have instead proposed a community-based tiger conservation model
Generalized Zero-Shot Learning via Synthesized Examples
We present a generative framework for generalized zero-shot learning where
the training and test classes are not necessarily disjoint. Built upon a
variational autoencoder based architecture, consisting of a probabilistic
encoder and a probabilistic conditional decoder, our model can generate novel
exemplars from seen/unseen classes, given their respective class attributes.
These exemplars can subsequently be used to train any off-the-shelf
classification model. One of the key aspects of our encoder-decoder
architecture is a feedback-driven mechanism in which a discriminator (a
multivariate regressor) learns to map the generated exemplars to the
corresponding class attribute vectors, leading to an improved generator. Our
model's ability to generate and leverage examples from unseen classes to train
the classification model naturally helps to mitigate the bias towards
predicting seen classes in generalized zero-shot learning settings. Through a
comprehensive set of experiments, we show that our model outperforms several
state-of-the-art methods, on several benchmark datasets, for both standard as
well as generalized zero-shot learning.Comment: Accepted in CVPR'1
The Hemispheric Asymmetry of Solar Activity During the Twentieth Century and the Solar Dynamo
We believe the Babcock--Leighton process of poloidal field generation to be
the main source of irregularity in the solar cycle. The random nature of this
process may make the poloidal field in one hemisphere stronger than that in the
other hemisphere at the end of a cycle. We expect this to induce an asymmetry
in the next sunspot cycle. We look for evidence of this in the observational
data and then model it theoretically with our dynamo code. Since actual polar
field measurements exist only from 1970s, we use the polar faculae number data
recorded by Sheeley (1991) as a proxy of the polar field and estimate the
hemispheric asymmetry of the polar field in different solar minima during the
major part of the twentieth century. This asymmetry is found to have a
reasonable correlation with the asymmetry of the next cycle. We then run our
dynamo code by feeding information about this asymmetry at the successive
minima and compare with observational data. We find that the theoretically
computed asymmetries of different cycles compare favourably with the
observational data, the correlation coefficient being 0.73. Due to the coupling
between the two hemispheres, any hemispheric asymmetry tends to get attenuated
with time. The hemispheric asymmetry of a cycle either from observational data
or from theoretical calculation statistically tends to be less than the
asymmetry in the polar field (as inferred from the faculae data) in the
preceding minimum. This reduction factor turns out to be 0.38 and 0.60
respectively in observational data and theoretical simulation.Comment: 14 pages, 6 figure
Design and Development of High Voltage High Pulse Power Supply using FPGA for Dynamic Impedance Matching
High Voltage High Pulse Power Supply (HVHPPS) is designed with the goal to match fixed load, so thatprecise pulse output can be achieved. Generally the loads involve magnetron, klystron, and particle accelerators etc. The HVHPPS output pulse shape changes with load impedance variation due to various reasons. Due to changes in impedance, the performance of Pulse Power Supply degrades and reflects the power at the source end which causes component failure and system shut down. To overcome such problems, a scale down High Voltage High Pulse Power is designed and developed to match the dynamic impedance variations upto 25 % of mismatch. In earlier days, all HVHPPS were designed using microcontrollers where the problem of pulse to pulse monitoring and computational speed was compromised. The availability of variable and self-defined, Field Programmable Gate Array (FPGA) controller, which provided flexibility to design the pulse to pulse shaping and various vital parameter monitoring, made it possible. This paper presents the design and implementation of HVHPPS over an FPGA platform to meet the fast response requirement. This paper provides a solution for impedance mismatch problems associated with such types of power supply, and also presents specifications for major components in a high voltage pulse power system for various types of load ranges. An experimental test hardware was designed and developed for HVHPPS to implement dynamic impedance algorithm and validate the results
Inflammatory cytokine profile of VEGF and IL-6 from the endometrium of women with and without endometriosis
Background: Endometriosis affects an estimated 176 million women worldwide, which constitutes 10% of the total female population causing debilitating symptoms of pelvic pain and infertility, which limits the quality of reproductive life of affected women. The present study aimed to assess the serum level of VEGF and pro-inflammatory marker IL-6 in cases and normal healthy control groups.Methods: VEGF and IL-6 serum levels were measured by competitive sandwich enzyme-linked immunosorbent assay (ELISA) from 34 subjects with surgically confirmed endometriosis, 16 subjects with adenomyosis and 18 similar age matched healthy controls with no clinical evidence of the disease or detectable endometriotic lesions at the time of surgical examination. Patients were characterized in terms of their socio-demographic and clinically diagnosed characteristics, including the validated infertility and chronic disease registries.Results: The mean serum level of VEGF was significantly (p<0.0001) higher in case of endometriosis (3887 ng/l) followed by adenomyosis (2588 ng/l) group and lower in case of normal healthy control (665 ng/l) group. The mean serum IL-6 was found to be highly significant (p<0.0001) in case of endometriosis (90.49 pg/ml) followed by adenomyosis (70.37 pg/ml) group and lower in case of normal healthy control (22.97 pg/ml) group.Conclusions: VEGF and IL-6 seems to play a crucial role in the implantation and development of endometriotic lesions, and the disease is associated with significant modulations in the serum levels of VEGF. IL-6 can be a reliable non-invasive diagnostic marker for endometriosis
Isolation and characterization of opportunistic fungi causing secondary infection in debilitated patients
An opportunistic infection is caused by variety of pathogens such as bacteria, virus, fungi or protozoans that usually do not cause disease in a healthy host. In order to accomplish the objectives of the present research work clinical samples were collected from debilitated patients. Out of 45 samples 27 were found to be positive for fungal infection. A total number of 76 mold form and ample number of Candida spp. clinical isolates were obtained. The common molds isolated were Alternaria alternata, A. fumigatus, A. niger, A. terreus, A. nidulans, A. flavus, Rhizopus spp. Mucur spp. and Curvularia lunata. In order to study the antifungal profile of the clinical isolates in vitro antifungal susceptibility test was performed by Kirby Bauer Method. Ketoconazole was found to be most effective azole against the clinical isolates followed by Clotrimazole, Itraconazole and Amphoterecin B
Investigation on the Effect of Cable Length on Pulse Shape of High Voltage High Pulse Power Supply
In the present scenario of pulse power applications, transmission of high voltage pulses varies as per load condition. In the early days of its application, High Voltage High Pulse Power Supply (HVHPPS) design saw short distance between load and source, where the effect of cable length was not taken into account for design. This paper presents the effect of cable length on pulse shape of High Voltage High Pulse Power Supply. The load under observation is Klystron based high energy particle accelerator system. The performance of pulse power systems were observed continuously on a daily basis throughout the year and detailed analysis was carried out. This paper generates the model of pulse forming system and provides details of pattern distortion of the pulse shape due to various dynamic parameter changes i.e. impedance, Load Voltage, Load Current, Cavity Dimensional Changes (Microwave components) due to temperature variations and performance of the power supply. The results were analysed and validated with hardware results across a range of actual industrial loads
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