3,358 research outputs found
Know2Look: Commonsense Knowledge for Visual Search
With the rise in popularity of social media, images accompanied by contextual text form a huge section of the web. However, search and retrieval of documents are still largely dependent on solely textual cues. Although visual cues have started to gain focus, the imperfection in object/scene detection do not lead to significantly improved results. We hypothesize that the use of background commonsense knowledge on query terms can significantly aid in retrieval of documents with associated images. To this end we deploy three different modalities - text, visual cues, and commonsense knowledge pertaining to the query - as a recipe for efficient search and retrieval
An Imaging Polarimeter(IMPOL) for multi-wavelength observations
Taking advantage of the advances in array detector technology, an imaging
polarimeter (IMPOL) has been constructed for measuring linear polarization in
the wavelength band from 400-800 nm. It makes use of a Wollaston prism as the
analyser to measure simultaneously the two orthogonal polarization components
that define a Stoke's parameter. An achromatic half-wave plate is used to
rotate the plane of polarization with respect to the axis of the analyser so
that the second Stoke's parameter also can be determined. With a field of view
correponding to about 30x30 sq. mm for a 1.2 m, f/13 telescope, a sensitive,
liquid-nitrogen cooled CCD camera as the detector and a built-in acquisition
and guidance unit, the instrument can be used for studying stellar fields or
extended objects with an angular resolution close to 2 arcsec. The instrumental
polarization is less than 0.05% and the accuracies of measurement are primarily
limited by photon noise for typical observations.Comment: 10 pages including 5 embedded figures; submitted to Astronomy and
Astrophysics Supplement Series; available on request to A. N. Ramaprakash
([email protected] or [email protected]); quote report n
Studying the Imaging Characteristics of Ultra Violet Imaging Telescope (UVIT) through Numerical Simulations
Ultra-Violet Imaging Telescope (UVIT) is one of the five payloads aboard the
Indian Space Research Organization (ISRO)'s ASTROSAT space mission. The science
objectives of UVIT are broad, extending from individual hot stars, star-forming
regions to active galactic nuclei. Imaging performance of UVIT would depend on
several factors in addition to the optics, e.g. resolution of the detectors,
Satellite Drift and Jitter, image frame acquisition rate, sky background,
source intensity etc. The use of intensified CMOS-imager based photon counting
detectors in UVIT put their own complexity over reconstruction of the images.
All these factors could lead to several systematic effects in the reconstructed
images. A study has been done through numerical simulations with artificial
point sources and archival image of a galaxy from GALEX data archive, to
explore the effects of all the above mentioned parameters on the reconstructed
images. In particular the issues of angular resolution, photometric accuracy
and photometric-nonlinearity associated with the intensified CMOS-imager based
photon counting detectors have been investigated. The photon events in image
frames are detected by three different centroid algorithms with some energy
thresholds. Our results show that in presence of bright sources, reconstructed
images from UVIT would suffer from photometric distortion in a complex way and
the presence of overlapping photon events could lead to complex patterns near
the bright sources. Further the angular resolution, photometric accuracy and
distortion would depend on the values of various thresholds chosen to detect
photon events.Comment: Submitted to PASP, 16 Pages, 9 figure
Geomagnetic Activity and Solar M-regions for the Current Epoch of the Sunspot Minimum
The analysis of geomagnetic activity has been made for the period 1950-54 and four sequences of annual variations have been detected. It has been shown that the most predominant effect of M-regions is observable only on particular dates separated at an interval of 27 days. In the last section the possibility of the association of M-regions with various solar features has been discussed and it is found that they can be identified with unipolar magnetic regions which may also be the seat of low coronal line intensities
New opportunities for Indian space astronomy
This article does not have an abstract
Adsorption efficiency of carbon prepared from agricultural waste materials in removing basic dye from aqueous solution
Management of solid waste is the burgeoning issue of the current times. Agriculture waste is rich in org. material like cellulose, lignin etc. and can be of great use if utilized as right resource at right time and right place. In the current study agriculture waste material has been used for adsorption of color from waste water. Sugarcane bagasse and paddy straw have been recycled to activated carbon and have been utilized and compared as the adsorbent for the removal of basic dye from aq. soln. A basic dye, methylene blue has been used as the adsorbate. Two different mineral acids have been used for activation of raw material and it was obsd. that both H3PO4 and HNO3 were good activating agent but impregnation efficiency was in following order H3PO4 > HNO3. Adsorption expts. were conducted by varying several parameters namely pH, adsorbent dose, initial concn. of dye and contact time. It was obsd. that color was effectively removed at all selected pH and the increase in activated carbon dose showed an increase in its adsorption efficiency. The percentage of color removal decreased with an increase in the initial dye concn. More than 90 % adsorption efficiency of dye from soln. contg. 10 mg/L of dye was attained with an adsorbent dosage of 0.1 g after 45 min of contact time at all pH. Results obtained indicate that agriculture waste material could be employed as a low cost alternative to com. activated carbon in wastewater treatment for dye removal and can thus be a good example of wealth from waste
Adsorption efficiency of carbon from treated sugarcane bagasse in removing chromium (VI) from aqueous solutions by optimization of adsorption parameters
Adsorption is one of the effective techniques for removal of chromium (VI) from wastewater. In the present study, efforts have been made to develop adsorption technology for removing Chromium (Cr) VI from aqueous solutions by using sugarcane bagasse a waste which is left after taking out the juice. Activated carbon was prepared from waste sugarcane bagasse by chemical activation with orthophosphoric acid and burning for 3 hrs. Batch adsorption studies carried out showed that the adsorbent prepared from sugarcane bagasse has a significantcapacity in removing Cr (VI) from aqueous solutions. Optimization of certain adsorption process factors i.e. pH, agitation time; adsorbent dose and adsorbate concentration were also made
A Model for the Lubrication Mechanism in Knee Joint Replacement
Analytical studies are presented for the understanding of the lubrication mechanism occuring in knee joint replacement under restricted motion. The idealised model has been shown to produce results consistent with those in normal situations. Effects of increase in viscoelastic parameter of the lubricant are similar to those of increase in the concentration of hyaluronic acid molecules in synovial fluid. Slip velocity occuring at the poroelastic boundary helps in normal functioning of the joints
Social media users’ online subjective well-being and fatigue: A network heterogeneity perspective
Scholars have drawn increasing attention to the implications of the dark side of social media for users’ online subjective well-being (OSWB). We develop a research framework based on the limited-capacity model to examine the relationship between OSWB and social media fatigue. Moreover, we explore the associations between specific aspects related to network heterogeneity and social media fatigue for social media users in the United States of America (USA). Further, we examine the mediating effect of network heterogeneity on the association between OSWB and social media fatigue. We utilised a cross-sectional research design to collect data from Prolific Academic (N = 320) and analysed the data through structural equation modelling. The results indicate that OSWB is positively correlated with the network heterogeneity aspect of self-disclosure and negatively correlated with social comparison. OSWB, moreover, is negatively correlated with fatigue, while privacy concerns and self-disclosure are positively correlated with fatigue. Further, of the network heterogeneity aspects we considered, only social comparison is a partial mediator for the relationship between OSWB and social media fatigue. The findings provide insights into the pathways through which social media users’ OSWB and network heterogeneity can induce social media fatigue, raising critical implications for theory and practice
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