152 research outputs found

    Aspect angle estimation of targets in forward looking infrared images using the model-based vision approach

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    We develop a model-based vision algorithm to estimate the aspect angle of a target in a forward-looking infrared (FLIR) image. In the preprocessing stage of the algorithm, a set of 3-D voxel-based models is created using a CAD/CAM package. These models are rotated about the vertical axis through a series of predetermined angles and then projected onto the horizontal plane. This gives us a database library of 2-D images. We select as signature from a given FLIR image and attempt to match it with the various images in the given database library of images using the normalized cross-correlation method. The angle of rotation corresponding to the image in the database library giving the best possible match is estimated to be the aspect angle of the signature (target). We use an algebraic approach to represent images and the process involves certain algebraic operations on the polynomials. An advantage of the algebraic approach is that a high speedup in the run time is possible if the fast Fourier transform is used to compute the polynominal multiplications involved in the processing

    On the modular representation of permutation groups of prime power degree

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    AbstractPermutation groups of prime power degree are investigated here through the study of the corresponding group algebra of the set of all functions from the underlying set on which the permutation group acts to a finite field of characteristic p. For the case when the permutation group is of degree p2 acting on a set consisting of the direct product of two elementary abelian p-groups, the structure of a minimal permutation module is obtained under certain conditions. The proofs do not depend on the recent classification results of finite simple groups

    A Model of Optimal Development for an Economy with an Informal Sector

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    Inequalities in Child Mortality in India: A District-Level Analysis

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    This paper measures the degree of inequality in child mortality rates across districts in India, using data from the 1981, 1991 and 2001 Indian population censuses. The results show that child mortality is more concentrated in less developed districts in all three census years. Further, between 1981 and 2001, the inequality in child mortality seems to have increased to the advantage of the more developed districts (i.e., there was an increasing concentration of child mortality in less developed districts). However, the inequality in female child mortality rates seems to have declined between 1991 and 2001, even as it increased – albeit at a slower rate than before – for male child mortality rates. In the decomposition analysis, it is found that while a more equitable distribution of medical facilities and safe drinking water across districts did contribute towards reducing inequality in child mortality between 1981 and 1991, different levels of structural change among districts were responsible for a very large part of the inequality in child mortality to the advantage of the more developed districts in all three census years. Other variables which played important roles in increasing inequality included a measure of infrastructure development, female literacy, and a social group status variable. The paper concludes with some brief comments on the policy implications of the findings

    India in the Rise of Britain and Europe: A Contribution to the Convergence and Great Divergence Debates

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    This paper discusses the role of the British control of India in the rise of Britain and Europe as well as in the convergence in incomes within the Atlantic economy in the late nineteenth century. Britain was at the apex of the world economy throughout most of the nineteenth century. The paper argues that the emergence of Britain as the apex economic and political power depended on her control over India.This control of India then enabled Britain to pursue a set of policies that were of critical importance both for the convergence in incomes within the Atlantic economy and the rise of Europe. The thesis advanced here can be viewed, depending on one's prior position, as being either complementary to or alternative to the views of many of the protagonists of the divergence debate in the literature

    A potential cyanobacterial ancestor of Viridiplantae chloroplasts

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    The theory envisaging the origin of plastids from endosymbiotic cyanobacteria is well-established but it is difficult to explain the evolution (spread) of plastids in phylogenetically diverse plant groups. It is widely believed that primordial endosymbiosis occurred in the last common ancestor of all algae^1^, which then diverged into the three primary photosynthetic eukaryotic lineages, viz. the Rhodophyta (red algae), Glaucocystophyta (cyanelle-containing algae) and Viridiplantae (green algae plus all land plants)^2^. Members of these three groups invariably have double membrane-bound plastids^3^, a property that endorses the primary endosymbiotic origin of the organelles. On the other hand, the three or four membrane-bound plastids of the evolutionary complicated Chromalveolates [chromista (cryptophytes, haptophytes, and stramenopiles) and alveolata (dinoflagellates, apicomplexans, and ciliates)] are inexplicable in the light of a single endosymbiosis event, thereby necessitating the postulation of the secondary^4,5^ and tertiary^6^ endosymbiosis theories where a nonphotosynthetic protist supposedly engulfed a red or a green alga^7^ and an alga containing a secondary plastid itself was engulfed^8^ respectively. In the current state of understanding, however, there is no clue about the taxonomic identity of the cyanobacterial ancestor of chloroplasts, even though there is a wide consensus on a single primordial endosymbiosis event. During our metagenomic investigation of a photosynthetic geothermal microbial mat community we discovered a novel order-level lineage of Cyanobacteria that - in 16S rRNA gene sequence-based phylogeny - forms a robust monophyletic clade with chloroplast-derived sequences from diverse divisions of Viridiplantae. This cluster diverged deeply from the other major clade encompassing all hitherto known groups of Cyanobacteria plus the chloroplasts of Rhodophyta, Glaucocystophyceae and Chromalveolates. Since this fundamental dichotomy preceded the origin of all chloroplasts, it appears that two early-diverging cyanobacterial lineages had possibly given rise to two discrete chloroplast descents via two separate engulfment events

    A coastal groundwater management model with Indian case study

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    The complexity of the hydrogeological setup in coastal areas calls for the adoption of scientific groundwater management techniques. Excessive withdrawal of groundwater in coastal zones will lead to depression of the water table, with associated hazards such as putting the well out of use, rendering abstraction uneconomic with increased lift. A sustained regional groundwater drawdown below sea level runs the risk of saline water intrusion, even for confined coastal aquifers. Uncontrolled groundwater development may lead to reversal of the freshwater gradient, thereby resulting in saline water ingress into coastal aquifers. There are, however, several established methodologies to control and minimise the problems associated with groundwater extraction followed by saline water intrusion. This study developed a convenient and easily implementable analytical model for coastal groundwater management aimed at the control of saltwater intrusion. The technique includes withdrawal of coastal freshwater by means of qanat-well structures associated with artificial recharge through rainwater harvesting aided by percolation ponds and recharge wells. The proposed methodology is suitable specifically for not highly urbanised coastal areas with significant annual precipitation, good hydraulic conductivity of the aquifer and a low depth of fresh groundwater. As a case study, the model is applied to a coastal zone of the Purba Medinipur district of West Bengal, India. Adequate quantifications of the efficiency of the methodology are incorporated and relevant conclusions are drawn

    Histopathological Image Analysis with Style-Augmented Feature Domain Mixing for Improved Generalization

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    Histopathological images are essential for medical diagnosis and treatment planning, but interpreting them accurately using machine learning can be challenging due to variations in tissue preparation, staining and imaging protocols. Domain generalization aims to address such limitations by enabling the learning models to generalize to new datasets or populations. Style transfer-based data augmentation is an emerging technique that can be used to improve the generalizability of machine learning models for histopathological images. However, existing style transfer-based methods can be computationally expensive, and they rely on artistic styles, which can negatively impact model accuracy. In this study, we propose a feature domain style mixing technique that uses adaptive instance normalization to generate style-augmented versions of images. We compare our proposed method with existing style transfer-based data augmentation methods and found that it performs similarly or better, despite requiring less computation and time. Our results demonstrate the potential of feature domain statistics mixing in the generalization of learning models for histopathological image analysis.Comment: Paper is published in MedAGI 2023 (MICCAI 2023 1st International Workshop on Foundation Models for General Medical AI) Code link: https://github.com/Vaibhav-Khamankar/FuseStyle Paper link: https://nbviewer.org/github/MedAGI/medagi.github.io/blob/main/src/assets/papers/P17.pd

    Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO3_3/Ag nanocomposite

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    We report observation of more than an order of magnitude jump in saturation magnetization in BiFeO3_3/Ag nanocomposite at room temperature compared to what is observed in bare BiFeO3_3 nanoparticles. Using transmission electron microscopy together with energy dispersive x-ray spectra (which maps the element concentration across the BiFeO3_3/Ag interface) and x-ray photoelectron spectroscopy, we show that both the observed specific self-assembly pattern of BiFeO3_3 and Ag nanoparticles and the charge transfer between Ag and O are responsible for such an enormous rise in room-temperature magnetization. The BiFeO3_3/Ag nanocomposites, therefore, could prove to be extremely useful for a variety of applications including biomedical.Comment: 11 pages, 7 figures, accepted for publication in Nanotechnolog

    Graphene and amyloid peptide binding and its implications in Alzheimer's disease

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    A poster discussing the relation of graphene and amyloid peptide binding to Alzheimer's disease
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