7,964 research outputs found

    An improved block matching algorithm for motion estimation in video sequences and application in robotics

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    Block Matching is one of the most efficient techniques for motion estimation for video sequences. Metaheuristic algorithms have been used effectively for motion estimation. In this paper, we propose two hybrid algorithms: Artificial Bee Colony with Differential Evolution and Harmony Search with Differential Evolution based motion estimation algorithms. Extensive experiments are conducted using four standard video sequences. The video sequences utilized for experimentation have all essential features such as different formats, resolutions and number of frames which are generally required in input video sequences. We compare the performance of the proposed algorithms with other algorithms considering various parameters such as Structural Similarity, Peak Signal to Noise Ratio, Average Number of Search Points etc. The comparative results demonstrate that the proposed algorithms outperformed other algorithms

    COMPARATIVE PHYSICOCHEMICAL, PHYTOCHEMICAL AND HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY EVALUATION OF HEART WOOD AND SMALL BRANCHES OF AQUILARIA AGALLOCHA ROXB.

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    Aquilaria agallocha Roxb. commonly called as Agaru is a medicinal plant. Heartwood of this tree is widely used in Ayurveda for various diseases. Removal of heart wood from trunk of this tree may make this plant weak and susceptible to damage due to which availability of this plant may be difficult in near future. Present study outlines the concept of plant part substitution. Heart wood and small branches of A. agallocha are compared on the basis of physicochemical analysis, phytochemical analysis, total phenolic contents, total flavonoid contents and high performance thin layer chromatography (HPTLC) to evaluate the possibilities of using small branches instead of heart wood. Physicochemical parameters of heartwood and small branches and phytochemical analysis of n-hexane, ethyl acetate and ethanol extract of both heart wood and small branches were carried out using standard methods. Total phenolics and total flavonoids were estimated spectrophotometrically using Folin-ciocalteu assayand aluminum chloride assaymethods, respectively. CAMAG HPTLC system equipped with semi-automatic applicator was used for HPTLC of n-hexane, ethyl acetate and ethanol extracts of stem bark and small braches using suitable mobile phases. Results of phytochemical analysis and HPTLC of n-hexane, ethyl acetate and ethanol extracts showed many similarities whichsuggest that small branches may have nearly similar active potency like heart wood and may be used as a substitute of heart wood after comparison and confirmation of same for pharmacological activities

    Charge and Spin Response of the Spin--Polarized Electron Gas

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    The charge and spin response of a spin--polarized electron gas is investigated including terms beyond the random phase approximation. We evaluate the charge response, the longitudinal and transverse spin response, and the mixed spin--charge response self--consistently in terms of the susceptibility functions of a non--interacting system. Exchange--correlation effects between electrons of spin σ\sigma and σ\sigma^{'} are included following Kukkonen and Overhauser, by using spin--polarization dependent generalized Hubbard local field factors Gσ±{G_\sigma}^{\pm} and Gσˉ±{G_{\bar\sigma}}^{\pm}. The general condition for charge--density and spin--density--wave excitations of the system is discussed.Comment: 4 pages, latex, no figure

    SUBSTITUTION OF ROOTS WITH SMALL BRANCHES OF RAUWOLFIA SERPENTINA FOR THERAPEUTIC USES - A PHYTOCHEMICAL APPROACH

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    Rauwolfia serpentina commonly called Sarpagandha is a medicinal plant widely used in Ayurveda. As per the Ayurvedic literature, roots of this plant are used in cardiac disorder, cancer, mental illness and psychiatric disorder. To collect roots for medicinal purpose whole plant is uprooted on a mass scale from their natural habitat which is leading to depletion of resources, due to which plant may be difficult in near future for use in traditional systems of medicine. Present study was carried out to assess possibilities of using small branches of R. serpentina in place of its roots which will help in conservation of this plant and availability of raw material for therapeutic purposes. Roots and small branches of R. serpentina are compared on the basis of physicochemical analysis, phytochemical analysis, total phenolic contents, total flavonoid contents and high performance thin layer chromatography (HPTLC) to evaluate the possibilities of using small branches in place of its roots. Results of phytochemical analysis and HPTLC of n-hexane, ethyl acetate and ethanol extracts showed many similarities whichsuggest that small branches may have nearly similar active constituents like roots and may be used as a substitute of roots after comparison and confirmation of same for pharmacological activities

    Multithermal apparent damping of slow waves due to strands with a Gaussian temperature distribution

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    Funding: T.V.D. was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 724326), the C1 grant TRACEspace of Internal Funds KU Leuven, and a Senior Research Project (G088021N) of the FWO Vlaanderen. V.P. is supported by SERB start-up research grant (File no. SRG/2022/001687). A.W.H. acknowledges the financial support of the Science and Technology Facilities Council (STFC) through Consolidated Grants ST/S000402/1 and ST/W001195/1 to the University of St Andrews and support from the European Research Council (ERC) Synergy grant “The Whole Sun” (810218).Context Slow waves in solar coronal loops are strongly damped, but the current theory of damping by thermal conduction cannot explain some observational features. Aims We investigated the propagation of slow waves in a coronal loop built up from strands of different temperatures. Methods We considered the loop to have a multithermal, Gaussian temperature distribution. The different propagation speeds in different strands led to a multithermal apparent damping of the wave, similar to observational phase mixing. We used an analytical model to predict the damping length and propagation speed for the slow waves, including in imaging with filter telescopes. Results   We compared the damping length due to this multithermal apparent damping with damping due to thermal conduction and found that the multithermal apparent damping is more important for shorter period slow waves. We quantified the influence of instrument filters on the wave’s propagation speed and damping. This allowed us to compare our analytical theory to forward models of numerical simulations. Conclusions We find that our analytical model matches the numerical simulations very well. Moreover, we offer an outlook for using the slow wave properties to infer the loop’s thermal properties.Peer reviewe

    Observation of semiannual and annual oscillation in equatorial middle atmospheric long term temperature pattern

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    Extensive measurement of middle atmospheric temperature with the help of lidar data of more than 10 years (1998–2008) and TIMED/SABER data of 7 years (2002–2008), has been carried out from a low latitude station, Gadanki, India (13.5° N, 79.2° E), which exhibits the presence of semiannual oscillation (SAO) and annual oscillation (AnO). The AnO component is stronger in the mesospheric region (80–90 km) and the SAO is dominant at stratospheric altitudes (30–50 km). Overall, the AnO possesses higher amplitude ~6–7 K, and the SAO shows less amplitude ~1–2 K. The AnO present at 90 km finds crest near summer solstice, and the same at 80 km shows peak near winter solstice with a downward progression speed ~1.7 km/month. The SAO propagates downward with an average phase speed ~9 km/month and phase maximizes around equinox and solstice at 50 and 30 km, respectively. The observed SAO has also shown seasonal asymmetry in peaks
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