354 research outputs found

    Multimodal decision-level fusion for person authentication

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    In this paper, the use of clustering algorithms for decision-level data fusion is proposed. Person authentication results coming from several modalities (e.g., still image, speech), are combined by using fuzzy k-means (FKM), fuzzy vector quantization (FVQ) algorithms, and median radial basis function (MRBF) network. The quality measure of the modalities data is used for fuzzification. Two modifications of the FKM and FVQ algorithms, based on a novel fuzzy vector distance definition, are proposed to handle the fuzzy data and utilize the quality measure. Simulations show that fuzzy clustering algorithms have better performance compared to the classical clustering algorithms and other known fusion algorithms. MRBF has better performance especially when two modalities are combined. Moreover, the use of the quality via the proposed modified algorithms increases the performance of the fusion system

    Surgical correction of valvular pathology in infants and children. Results and perspectives

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    Department of Cardiac Surgery, Republican Hospital, Chisinau, the Republic of MoldovaBackground: Valvular pathology in infants and children pose numerous problems such as valvular narrow rings, inconveniences of mechanical valves prosthesis, accelerated degeneration of bioprosthetic valves and homografts. Valvular repair is the goal of intervention, because restoration of valvular anatomy and function allows growth and avoids the problems of valvular substitution. When reconstruction fails or is not feasible, valve replacement becomes inevitable. The goal of this article is to address valve surgical options for all four valve positions within the pediatric sector. We review current literature and our practice to support our preferences. Material and methods: A group of 205 patients under the age of 18 with valvular pathology was operated on at our institution in 1988-2006. Results: Hospital mortality was 4.3% in aortic group and 5.4% in a mitral group of patients. Valvular repair was possible in 84% and 78.3% of each group respectively. Aortic annuloplasty was done in 6.4% of patients. We inserted minimal 21 mm prosthesis in a mitral position and 19 mm in aortic position. Long – term results need to be evaluated. Conclusions: A multitude of options and surgical experiences exist. Valvular repair remains a procedure of choice in a pediatric group of patients

    Enhancing reliability and efficiency for real-time robust adaptive steganography using cyclic redundancy check codes

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    The development of multimedia and deep learning technology bring new challenges to steganography and steganalysis techniques. Meanwhile, robust steganography, as a class of new techniques aiming to solve the problem of covert communication under lossy channels, has become a new research hotspot in the field of information hiding. To improve the communication reliability and efficiency for current real-time robust steganography methods, a concatenated code, composed of Syndrome–Trellis codes (STC) and cyclic redundancy check (CRC) codes, is proposed in this paper. The enhanced robust adaptive steganography framework proposed is this paper is characterized by a strong error detection capability, high coding efficiency, and low embedding costs. On this basis, three adaptive steganographic methods resisting JPEG compression and detection are proposed. Then, the fault tolerance of the proposed steganography methods is analyzed using the residual model of JPEG compression, thus obtaining the appropriate coding parameters. Experimental results show that the proposed methods have a significantly stronger robustness against compression, and are more difficult to be detected by statistical based steganalytic methods

    Universal DNA methylation age across mammalian tissues

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    Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals

    Neural Correlates of the Difference between Working Memory Speed and Simple Sensorimotor Speed: An fMRI Study

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    The difference between the speed of simple cognitive processes and the speed of complex cognitive processes has various psychological correlates. However, the neural correlates of this difference have not yet been investigated. In this study, we focused on working memory (WM) for typical complex cognitive processes. Functional magnetic resonance imaging data were acquired during the performance of an N-back task, which is a measure of WM for typical complex cognitive processes. In our N-back task, task speed and memory load were varied to identify the neural correlates responsible for the difference between the speed of simple cognitive processes (estimated from the 0-back task) and the speed of WM. Our findings showed that this difference was characterized by the increased activation in the right dorsolateral prefrontal cortex (DLPFC) and the increased functional interaction between the right DLPFC and right superior parietal lobe. Furthermore, the local gray matter volume of the right DLPFC was correlated with participants' accuracy during fast WM tasks, which in turn correlated with a psychometric measure of participants' intelligence. Our findings indicate that the right DLPFC and its related network are responsible for the execution of the fast cognitive processes involved in WM. Identified neural bases may underlie the psychometric differences between the speed with which subjects perform simple cognitive tasks and the speed with which subjects perform more complex cognitive tasks, and explain the previous traditional psychological findings
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