6,865 research outputs found

    Adaptive Image Denoising by Targeted Databases

    Full text link
    We propose a data-dependent denoising procedure to restore noisy images. Different from existing denoising algorithms which search for patches from either the noisy image or a generic database, the new algorithm finds patches from a database that contains only relevant patches. We formulate the denoising problem as an optimal filter design problem and make two contributions. First, we determine the basis function of the denoising filter by solving a group sparsity minimization problem. The optimization formulation generalizes existing denoising algorithms and offers systematic analysis of the performance. Improvement methods are proposed to enhance the patch search process. Second, we determine the spectral coefficients of the denoising filter by considering a localized Bayesian prior. The localized prior leverages the similarity of the targeted database, alleviates the intensive Bayesian computation, and links the new method to the classical linear minimum mean squared error estimation. We demonstrate applications of the proposed method in a variety of scenarios, including text images, multiview images and face images. Experimental results show the superiority of the new algorithm over existing methods.Comment: 15 pages, 13 figures, 2 tables, journa

    Achieving a Vision of Success For English Language Learners

    Get PDF
    This qualitative research study explored participant perceptions of a district-sponsored leadership program for Language Learners, the International Youth Leadership Council, specifically as it applies to student advocacy, leadership, empowerment, and voice. This study utilized Critical Race Theory and Culturally Relevant Pedagogy to examine a comparison of participant perceptions of personal and institutional barriers to leadership opportunities for Emergent Bilingual students in American educational systems and their experience participating in the district’s leadership program specifically designed for Emergent Bilingual students. Results showed that participants in the district’s Emergent Bilingual leadership program experienced high cultural alignment, racially, culturally, and linguistically aligned support staff, and increases in leadership, social justice and advocacy skills, and academic success as a result of participation in the district’s International Youth Leadership Council. By contrast, participants shared narratives regarding marginalization, stigmatization, teacher low expectations, and invisibility in American educational systems in regard to access to leadership and academic opportunities at the high school level. This qualitative study investigated student and staff participants of the International Youth Leadership Council’s activities for English Learners and of these activities’ impact on student participants’ leadership skills, sense of empowerment, and student voice. The study explored the results and its implications for education and English Language Learners, specifically regarding participant perception of racially, culturally and linguistically aligned leadership programs

    Lumped Parameters in Permanent Displacement

    Get PDF
    New dynamic spring and damping values, which are dependent on the frequency, have been introduced into calculations of horizontal permanent displacement. The new dynamic damping value, which is inversely proportional to the circular frequency, has the same form as the material damping, while the new value of stiffness increases with increase in circular frequency. Similar methods can be used to obtain new dynamic spring and damping values for other modes of vibrations such as vertical, rocking and torsional. An analytical treatment of the coupled rocking and sliding modes is presented which considers horizontal and vertical Coulomb friction forces, two-layered soil deposits and also the vertical vibration

    Parametric Study of Horizontal Permanent Displacement on Sand

    Get PDF
    Dynamic loading such as cyclic loading should be taken into account in designing shallow foundations for any dynamically related structures. Horizontal permanent displacement, which can occur at any time due to wind and/or wave and dynamic loads of moving vehicles, can significantly reduce the bearing capacity of the footing. Effects of dynamic soil properties, e.g. frequency, Poisson\u27s ratio, Young\u27s modulus, on the permanent displacement are considered and the assumption of the linear variation between deformation and cycles can be used to predict the long-term horizontal permanent displacement. Sensitivity analyses for both pure sliding and coupled rocking and sliding vibrations of a rigid rectangular footing are also carried out with the following variables: internal damping, added soil mass, rocking level, amplitude of cyclic load and initial constant horizontal load

    An HMM-based Comparative Genomic Framework for Detecting Introgression in Eukaryotes

    Full text link
    One outcome of interspecific hybridization and subsequent effects of evolutionary forces is introgression, which is the integration of genetic material from one species into the genome of an individual in another species. The evolution of several groups of eukaryotic species has involved hybridization, and cases of adaptation through introgression have been already established. In this work, we report on a new comparative genomic framework for detecting introgression in genomes, called PhyloNet-HMM, which combines phylogenetic networks, that capture reticulate evolutionary relationships among genomes, with hidden Markov models (HMMs), that capture dependencies within genomes. A novel aspect of our work is that it also accounts for incomplete lineage sorting and dependence across loci. Application of our model to variation data from chromosome 7 in the mouse (Mus musculus domesticus) genome detects a recently reported adaptive introgression event involving the rodent poison resistance gene Vkorc1, in addition to other newly detected introgression regions. Based on our analysis, it is estimated that about 12% of all sites withinchromosome 7 are of introgressive origin (these cover about 18 Mbp of chromosome 7, and over 300 genes). Further, our model detects no introgression in two negative control data sets. Our work provides a powerful framework for systematic analysis of introgression while simultaneously accounting for dependence across sites, point mutations, recombination, and ancestral polymorphism
    • …