19 research outputs found

    Dynamics of Functional Meanings in Discourse

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    Master'sMASTER OF ART

    The Dynamical Distinction between Elliptical and Lenticular Galaxies in Distant Clusters: Further Evidence for the Recent Origin of S0 Galaxies

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    We examine resolved spectroscopic data obtained with the Keck II telescope for 44 spheroidal galaxies in the fields of two rich clusters, Cl0024+16 (z=0.40) and MS0451-03 (z=0.54), and contrast this with similar data for 23 galaxies within the redshift interval 0.3<z<0.65 in the GOODS northern field. For each galaxy we examine the case for systemic rotation, derive central stellar velocity dispersions sigma and photometric ellipticities, epsilon. Using morphological classifications obtained via Hubble Space Telescope imaging as the basis, we explore the utility of our kinematic quantities in distinguishing between pressure-supported ellipticals and rotationally-supported lenticulars (S0s). We demonstrate the reliability of using the v/(1-epsilon) vs sigma and v/sigma vs epsilon distributions as discriminators, finding that the two criteria correctly identify 63%+-3% and 80%+-2% of S0s at z~0.5, respectively, along with 76%+8-3% and 79%+-2% of ellipticals. We test these diagnostics using equivalent local data in the Coma cluster, and find that the diagnostics are similarly accurate at z=0. Our measured accuracies are comparable to the accuracy of visual classification of morphologies, but avoid the band-shifting and surface brightness effects that hinder visual classification at high redshifts. As an example application of our kinematic discriminators, we then examine the morphology-density relation for elliptical and S0 galaxies separately at z~0.5. We confirm, from kinematic data alone, the recent growth of rotationally-supported spheroidals. We discuss the feasibility of extending the method to a more comprehensive study of cluster and field galaxies to z~1, in order to verify in detail the recent density-dependent growth of S0 galaxies.Comment: 7 pages, 4 figures, updated with version accepted to Ap

    New spatiotemporal method for assessing video quality

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    The existence of temporal effects and temporal distortions in a video differentiate the way it is assessed from an image. Temporal effects and distortions can enhance or depress the visibility of spatial effects in a video. Thus, the temporal part of videos plays a significant role in determining the video quality. In this study, a spatiotemporal video quality assessment (VQA) method is proposed due to the importance of temporal effects and distortions in assessing video quality. Instead of measuring the frame quality on a frame basis, the quality of several averaged frames is measured. The proposed spatiotemporal VQA method is significantly improved compared with image quality assessment (IQA) methods applied on a frame basis. When combined with IQA methods, the proposed spatiotemporal VQA method has comparable performance with state-of-the-art VQA methods. The computational complexity of the proposed temporal method is also lower when compared with current VQA methods

    An error-based video quality assessment method with temporal information

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    t Videos are amongst the most popular online media for Internet users nowadays. Thus, it is of utmost importance that the videos transmitted through the internet or other transmission media to have a minimal data loss and acceptable visual quality. Video quality assessment (VQA) is a useful tool to determine the quality of a video without human intervention. A new VQA method, termed as Error and Temporal Structural Similarity (EaTSS), is proposed in this paper. EaTSS is based on a combination of error signals, weighted Structural Similarity Index (SSIM) and difference of temporal information. The error signals are used to weight the computed SSIM map and subsequently to compute the quality score. This is a better alternative to the usual SSIM index, in which the quality score is computed as the average of the SSIM map. For the temporal information, the second-order time-differential information are used for quality score computation. From the experiments, EaTSS is found to have competitive performance and faster computational speed compared to other existing VQA algorithms
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