1,723,569 research outputs found
Using visual feature extraction neural network model to improve performance of quadtree based image coding
No full textIn this paper, we propose a new technique to improve the performance of quadtree (QT) based image coding through the utilization of a neural network based visual feature extraction model(VFEM). After QT reconstruction is completed, a trained VFEM uses the information contained in the QT reconstructed image to recover the QT reconstruction error. This results in a better quality reconstructed image than the one simply reconstructed from QT representation. Since no extra information other than QT structure itself needs to be transmitted, the VFEM improvement does not increase the coding bit rate. Therefore, a better rate-distortion performance is achieved
Effect of vertex singularities on stress intensities near plate free surfaces
No full textThe stress intensity factor (SIF) distribution along the front of a through-the-thickness crack is significantly influenced by the presence of the 3D corner (vertex) singularities. All past 3D finite element studies indicated that for mode I, SIF rapidly decreases near the free surface and for mode II, it sharply increases. From the previous numerical simulations, it is unclear what the limiting values of SIF near the surface are and whether these values are infinite or bounded at the vertex point. In this paper, we conduct a careful finite element study and propose a theoretical equation, which describes the SIF behaviour near the vertex. We demonstrate that the asymptotic behaviour of SIF near the surface is governed by the difference in the strength of the corner and edge singularities. Furthermore, we validate our numerical approach and calculations by utilising the invariant properties of J-integral
Effect of vertex singularities on stress intensities near plate free surfaces
No full textThe stress intensity factor (SIF) distribution along the front of a through-the-thickness crack is significantly influenced by the presence of the 3D corner (vertex) singularities. All past 3D finite element studies indicated that for mode I, SIF rapidly decreases near the free surface and for mode II, it sharply increases. From the previous numerical simulations, it is unclear what the limiting values of SIF near the surface are and whether these values are infinite or bounded at the vertex point. In this paper, we conduct a careful finite element study and propose a theoretical equation, which describes the SIF behaviour near the vertex. We demonstrate that the asymptotic behaviour of SIF near the surface is governed by the difference in the strength of the corner and edge singularities. Furthermore, we validate our numerical approach and calculations by utilising the invariant properties of J-integral. © 2015 Wiley Publishing Ltd
Artificial neural network visual model for image quality enhancement
No full textAn artificial neural network visual model is developed, which extracts multi-scale edge features from the decompressed image and uses these visual features as input to estimate and compensate for the coding distortions. This provides a generic postprocessing technique that can be applied to all the main coding methods. Experimental results involving post-processing the JPEG and quadtree coding systems show that the proposed artificial neural network visual model significantly enhances the quality of reconstructed images, both in terms of the objective peak signal to noise ratio and subjective visual assessment
A generic postprocessing technique for image compression
No full textA postprocessing approach is developed for image coding applications. In this approach, a distortion-recovery model extracts multi-resolution edge features from the decompressed image and uses these visual features as input to estimate the difference image between the original uncompressed image and the decompressed image. Coding distortions are directly compensated by adding the model output to the decompressed image. Unlike the majority of existing postprocessing methods, which adopt filtering techniques to smooth blocking artifacts and are designed specifically for transform coding or vector quantization, the proposed approach is a generic postprocessing technique and can be applied to all of the main coding methods. Experiments involving postprocessing four coding systems were conducted, and the results obtained show that the proposed technique achieves significant improvements on the quality of reconstructed images, both in terms of the objective distortion measure and subjective visual assessment
Post-processing block coded images using artificial neural networks
No full textIn this paper, a technique employing artificial neural networks for post-processing block coded images is presented. Visually important image features are extracted from the decompressed image and used as input to a feedforward neural network. The neural network learns to reconstruct the difference image between the original (uncompressed) and the decompressed image. Coding artifact reduction is achieved by adding the neural networks output to the decompressed image. Experimental resultsusing the new technique for post-processingquadtree coded images are presented. It is shownthe new technique can significantly improve thecompressed image both in terms of peak signal to noise ratio (PSNR) and visual quality of the image
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Guest editorial guided lightwaves for sensors and measurement systems: advanced techniques and applications
No full textThis IEEE/OSA Journal of Lightwave Technology special issue on \u201cGuided Lightwaves for Sensors & Measurement Systems: Advanced Techniques and Applications\u201d is organized by the IEEE Instrumentation and Measurement Society. It aims to highlight the advancement of guided lightwaves in applications to sensors, instrumentation and measurement. The special issue includes both comprehensive review articles and original technical contributions covering the rapid advancement of guided lightwaves in the applications to instrumentation and measurement. 18 invited papers and 22 contributed papers will be published in this issue. The authors are from universities, government labs and industries. We hope that this JLT Special Issue will provide an in-depth look at the topic areas and serve as a valuable reference for the current and future scientists, engineers, and technical applicators working in the related fields.Peer reviewed: YesNRC publication: Ye
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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