274 research outputs found

    Reduction of blocking artifacts in both spatial domain and transformed domain

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    In this paper, we propose a bi-domain technique to reduce the blocking artifacts commonly incurred in image processing. Some pixels are sampled in the shifted image block and some high frequency components of the corresponding transformed block are discarded. By solving for the remaining unknown pixel values and the transformed coefficients, a less blocky image is obtained. Simulation results using the Discrete Cosine Transform and the Slant Transform show that the proposed algorithm gives a better quantitative result and image quality than that of the existing methods

    Experimental bond behaviour of GFRP and masonry bricks under impulsive loading

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    Fibre Reinforced Polymers have become a popular material for strengthening of masonry structures. The performance of this technique is strongly dependent on the bond between the FRP and the substrate. Understanding the strain rate effect on these materials and strengthening techniques is important for proper design and proper modelling of these systems under impacts or blast loads. This work aims to study the behaviour of the bond between GFRP and brick at different strain rates. A Drop Weight Impact Machine specially developed for pull-off tests (single shear tests) is used with different masses and different heights introducing different deformation rates. The strain rate effect on the failure mode, shear capacity and effective bond length is determined from the experimental results. Empirical relations of dynamic increase factors (DIF) for these materials and techniques are also presented.This work was performed under Project CH-SECURE (PTDC/EMC/120118/2010) funded by the Portuguese Foundation of Science and Technology – FCT. The authors acknowledge the support. The first author also acknowledges the support from his PhD FCT grant with the reference SFRH/BD/45436/2008

    An overview of digital speech watermarking

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    Digital speech watermarking is a robust way to hide and thus secure data like audio and video from any intentional or unintentional manipulation through transmission. In terms of some signal characteristics including bandwidth, voice/non-voice and production model, digital speech signal is different from audio, music and other signals. Although, various review articles on image, audio and video watermarking are available, there are still few review papers on digital speech watermarking. Therefore this article presents an overview of digital speech watermarking including issues of robustness, capacity and imperceptibility. Other issues discussed are types of digital speech watermarking, application, models and masking methods. This article further highlights the related challenges in the real world, research opportunities and future works in this area, yet to be explored fully

    Laboratory misdiagnosis of von Willebrand disease in post- menarchal females: A multi- center study

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    Increased awareness of von Willebrand Disease (VWD) has led to more frequent diagnostic laboratory testing, which insurers often dictate be performed at a facility with off- site laboratory processing, instead of a coagulation facility with onsite processing. Off- site processing is more prone to preanalytical variables causing falsely low levels of von Willebrand Factor (VWF) due to the additional transport required. Our aim was to determine the percentage of discordance between off- site and onsite specimen processing for VWD in this multicenter, retrospective study. We enrolled females aged 12 to 50- years who had off- site specimen processing for VWF assays, and repeat testing performed at a consulting institution with onsite coagulation phlebotomy and processing. A total of 263 females from 17 institutions were included in the analysis. There were 251 subjects with both off- site and onsite VWF antigen (VWF:Ag) processing with 96 (38%) being low off- site and 56 (22%) low onsite; 223 subjects had VWF ristocetin co- factor (VWF:RCo), 122 (55%) were low off- site and 71 (32%) were low onsite. Similarly, 229 subjects had a Factor VIII (FVIII) assay, and 67 (29%) were low off- site with less than half, 29 (13%) confirmed low with onsite processing. Higher proportions of patients demonstrated low VWF:Ag, VWF:RCo, and/or FVIII with off- site processing compared to onsite (McNemarʼs test P- value <.0005, for all assays). These results emphasize the need to decrease delays from sample procurement to processing for VWF assays. The VWF assays should ideally be collected and processed at the same site under the guidance of a hematologist.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156476/2/ajh25869.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156476/1/ajh25869_am.pd

    Radio Astronomy

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    Contains summary of research and reports on nine research projects.National Science Foundation (Grant AST81-21416)National Science Foundation (Grant AST82-14296)National Aeronautics and Space Administration (Grant S-10781-C)National Aeronautics and Space Administration (Grant NAGW-373)National Science Foundation (Grant AST79-19553)M.I.T. Sloan Fund for Basic ResearchNational Oceanic and Atmospheric Administration (Grant 04-8-M01-1)National Aeronautics and Space Administration (Grant NAG5-10)National Aeronautics and Space Administration (Contract NAS5-22929)Defense Advanced Research Projects Agency (Contract MDA 903-82-K-0521)Center for Advanced Television Studie

    Angiopoietin-2 Promotes Inflammatory Activation in Monocytes of Systemic Sclerosis Patients

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    Angiopoietin-2 (Ang-2), a ligand of the tyrosine kinase receptor Tie2, is essential for vascular development and blood vessel stability and is also involved in monocyte activation. Here, we examined the role of Ang-2 on monocyte activation in patients with systemic sclerosis (SSc). Ang-2 levels were measured in serum and skin of healthy controls (HCs) and SSc patients by ELISA and array profiling, respectively. mRNA expression of ANG2 was analyzed in monocytes, dermal fibroblasts, and human pulmonary arterial endothelial cells (HPAECs) by quantitative PCR. Monocytes were stimulated with Ang-2, or with serum from SSc patients in the presence of a Tie2 inhibitor or an anti-Ang2 neutralizing antibody. Interleukin (IL)-6 and IL-8 production was analyzed by ELISA. Ang-2 levels were elevated in the serum and skin of SSc patients compared to HCs. Importantly, serum Ang-2 levels correlated with clinical disease parameters, such as skin involvement. Lipopolysaccharide (LPS) LPS, R848, and interferon alpha2a (IFN-alpha) stimulation up-regulated the mRNA expression of ANG2 in monocytes, dermal fibroblasts, and HPAECs. Finally, Ang-2 induced the production of IL-6 and IL-8 in monocytes of SSc patients, while the inhibition of Tie2 or the neutralization of Ang-2 reduced the production of both cytokines in HC monocytes stimulated with the serum of SSc patients. Therefore, Ang-2 induces inflammatory activation of SSc monocytes and neutralization of Ang-2 might be a promising therapeutic target in the treatment of SSc
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