2,693 research outputs found

    MR image reconstruction using deep density priors

    Full text link
    Algorithms for Magnetic Resonance (MR) image reconstruction from undersampled measurements exploit prior information to compensate for missing k-space data. Deep learning (DL) provides a powerful framework for extracting such information from existing image datasets, through learning, and then using it for reconstruction. Leveraging this, recent methods employed DL to learn mappings from undersampled to fully sampled images using paired datasets, including undersampled and corresponding fully sampled images, integrating prior knowledge implicitly. In this article, we propose an alternative approach that learns the probability distribution of fully sampled MR images using unsupervised DL, specifically Variational Autoencoders (VAE), and use this as an explicit prior term in reconstruction, completely decoupling the encoding operation from the prior. The resulting reconstruction algorithm enjoys a powerful image prior to compensate for missing k-space data without requiring paired datasets for training nor being prone to associated sensitivities, such as deviations in undersampling patterns used in training and test time or coil settings. We evaluated the proposed method with T1 weighted images from a publicly available dataset, multi-coil complex images acquired from healthy volunteers (N=8) and images with white matter lesions. The proposed algorithm, using the VAE prior, produced visually high quality reconstructions and achieved low RMSE values, outperforming most of the alternative methods on the same dataset. On multi-coil complex data, the algorithm yielded accurate magnitude and phase reconstruction results. In the experiments on images with white matter lesions, the method faithfully reconstructed the lesions. Keywords: Reconstruction, MRI, prior probability, machine learning, deep learning, unsupervised learning, density estimationComment: Published in IEEE TMI. Main text and supplementary material, 19 pages tota

    Automatic License Plate Location and Recognition Algorithm for Color Images

    Get PDF
    An automatic car license plate location and recognition system has a great importance in today's industrial world for intelligent transport systems. Any automatic license plate location and recognition system has two main stages: (1) the license plate location and (2) the license plate recognition (LPR). The license plate location is the most important stage in the LPR systems which affects the system's accuracy, directly. Most of the previous methods are based on gray images but the color information is also an important factor to locate the license plate. In this project, we propose a novel license plate location algorithm for color images. The proposed algorithm is based on the brake lights and headlights of car. At the recognition stage, a well known and accepted character recognition algorithm has been used

    Primary headaches, attention deficit disorder and learning disabilities in children and adolescents

    Get PDF
    BACKGROUND: Primary headaches and Learning difficulties are both common in the pediatric population. The goal of our study was to assess the prevalence of learning disabilities and attention deficit disorder in children and adolescents with migraine and tension type headaches. METHODS: Retrospective review of medical records of children and adolescents who presented with headache to the outpatient pediatric neurology clinics of Bnai-Zion Medical Center and Meyer Children’s Hospital, Haifa, during the years 2009–2010. Demographics, Headache type, attention deficit disorder (ADHD), learning disabilities and academic achievements were assessed. RESULTS: 243 patients met the inclusion criteria and were assessed: 135 (55.6%) females and 108 (44.4%) males. 44% were diagnosed with migraine (35.8% of the males, 64.2% of the females, p = 0.04), 47.7% were diagnosed with tension type headache (50.4% of the males, 49.6% of the females). Among patients presenting with headache for the first time, 24% were formerly diagnosed with learning disabilities and 28% were diagnosed with attention deficit disorder (ADHD). ADHD was more prevalent among patients with tension type headache when compared with patients with migraine (36.5% vs. 19.8%, p = 0.006). Poor to average school academic performance was more prevalent among children with tension type headache, whereas good to excellent academic performance was more prevalent among those with migraine. CONCLUSIONS: Learning disabilities and ADHD are more common in children and adolescents who are referred for neurological assessment due to primary headaches than is described in the general pediatric population. There is an association between headache diagnosis and school achievements

    On the equivalence of strong formulations for capacitated multi-level lot sizing problems with setup times

    Get PDF
    Several mixed integer programming formulations have been proposed for modeling capacitated multi-level lot sizing problems with setup times. These formulations include the so-called facility location formulation, the shortest route formulation, and the inventory and lot sizing formulation with (l,S) inequalities. In this paper, we demonstrate the equivalence of these formulations when the integrality requirement is relaxed for any subset of binary setup decision variables. This equivalence has significant implications for decomposition-based methods since same optimal solution values are obtained no matter which formulation is used. In particular, we discuss the relax-and-fix method, a decomposition-based heuristic used for the efficient solution of hard lot sizing problems. Computational tests allow us to compare the effectiveness of different formulations using benchmark problems. The choice of formulation directly affects the required computational effort, and our results therefore provide guidelines on choosing an effective formulation during the development of heuristic-based solution procedures

    Determination of vapor bubble diameter of fc3284, fc84 and their binary mixtures during pool boiling

    Get PDF
    The bubble diameter of FC3284, FC84 and their mixtures during pool boiling were measured with a dual-probe which was located at a certain distance from the heating surface. In this study, temperature controlled heating surface was used. The difference between heating surface and saturation temperatures was increased gradually to obtain entire pool boiling regions at atmospheric pressure. Along the entire boiling curve, vapor bubble diameter was determined at that specified point. First of all, bubble diameter was determined for pure substances and their binary mixtures respectively. Different bubble diameters were determined in the different pool boiling regions. The results were compared with each other and with existing correlations in literature. It was found out that surface tension, viscosity and wall superheat are important factors which may affect the bubble departure diameter. At the beginning of the nucleate boiling, the results were in agreement with some related correlations in the literature and bubble diameters for pure substances FC3284 and FC84 were lower when compared to that of their binary mixtures.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

    Comparison of active vs. expectant management of the third stage of labor in women with low risk of postpartum hemorrhage: a randomized controlled trial

    Get PDF
    Objectives: To compare the ‘strictly’ active management protocol in women with low risk of postpartum hemorrhage using the expectant management protocol with respect to changes in hematologic parameters, uterotonics, blood transfusions, or additional interventions. Material and methods: A randomized controlled prospective trial in which 934 singleton parturients enrolled; 654 were randomly assigned to the active and mixed management groups. The primary outcome parameter was the reduction in hemoglobin concentrations due to delivery, and the secondary outcome parameters were changes in hemoglobin of more than 3 g/dL (ΔHb ≥ 3 g/dL), durations of the third stage of labor, need for additional uterotonic agents, blood transfusions, manual removal of the placenta, and surgical evacuation of retained products of conception. Results: The mean postpartum hemoglobin concentration was significantly higher (P = 0.04) in the active management group with a significantly lower reduction (P = 0.03). Falls of hemoglobin levels of more than 3 g/dL (ΔHb ≥ 3g/dL) were less common in the active management group though not significantly (P = 0.32). The mean duration of the third stage of labor was significantly (P < 0.001) shorter in the active management group. There was no significant difference between the two groups with regard to the need for additional uterotonic agents, uterine atony, blood transfusion, manual removal of the placenta, surgical evacuation of retained products of conception, and prolonged third stage of labor. Conclusions: Although active management of the third stage of labor was associated with higher postpartum hemoglobin levels, it did not influence the risk of ‘severe postpartum hemorrhage’ in women with low risk of postpartum hemorrhage

    The Energetic Particle Detector (EPD) Investigation and the Energetic Ion Spectrometer (EIS) for the Magnetospheric Multiscale (MMS) Mission

    Get PDF
    Abstract The Energetic Particle Detector (EPD) Investigation is one of 5 fields-and-particles investigations on the Magnetospheric Multiscale (MMS) mission. MMS comprises 4 spacecraft flying in close formation in highly elliptical, near-Earth-equatorial orbits targeting understanding of the fundamental physics of the important physical process called magnetic reconnection using Earth’s magnetosphere as a plasma laboratory. EPD comprises two sensor types, the Energetic Ion Spectrometer (EIS) with one instrument on each of the 4 spacecraft, and the Fly’s Eye Energetic Particle Spectrometer (FEEPS) with 2 instruments on each of the 4 spacecraft. EIS measures energetic ion energy, angle and elemental compositional distributions from a required low energy limit of 20 keV for protons and 45 keV for oxygen ions, up to \u3e0.5 MeV (with capabilities to measure up to \u3e1 MeV). FEEPS measures instantaneous all sky images of energetic electrons from 25 keV to \u3e0.5 MeV, and also measures total ion energy distributions from 45 keV to \u3e0.5 MeV to be used in conjunction with EIS to measure all sky ion distributions. In this report we describe the EPD investigation and the details of the EIS sensor. Specifically we describe EPD-level science objectives, the science and measurement requirements, and the challenges that the EPD team had in meeting these requirements. Here we also describe the design and operation of the EIS instruments, their calibrated performances, and the EIS in-flight and ground operations. Blake et al. (The Flys Eye Energetic Particle Spectrometer (FEEPS) contribution to the Energetic Particle Detector (EPD) investigation of the Magnetospheric Magnetoscale (MMS) Mission, this issue) describe the design and operation of the FEEPS instruments, their calibrated performances, and the FEEPS in-flight and ground operations. The MMS spacecraft will launch in early 2015, and over its 2-year mission will provide comprehensive measurements of magnetic reconnection at Earth’s magnetopause during the 18 months that comprise orbital phase 1, and magnetic reconnection within Earth’s magnetotail during the about 6 months that comprise orbital phase 2

    Restoration of CFTR function in patients with cystic fibrosis carrying the F508del-CFTR mutation

    Get PDF
    <div><p>Restoration of BECN1/Beclin 1-dependent autophagy and depletion of SQSTM1/p62 by genetic manipulation or autophagy-stimulatory proteostasis regulators, such as cystamine, have positive effects on mouse models of human cystic fibrosis (CF). These measures rescue the functional expression of the most frequent pathogenic CFTR mutant, F508del, at the respiratory epithelial surface and reduce lung inflammation in <i>Cftr<sup>F508del</sup></i> homozygous mice. Cysteamine, the reduced form of cystamine, is an FDA-approved drug. Here, we report that oral treatment with cysteamine greatly reduces the mortality rate and improves the phenotype of newborn mice bearing the <i>F508del-CFTR</i> mutation. Cysteamine was also able to increase the plasma membrane expression of the F508del-CFTR protein in nasal epithelial cells from <i>F508del</i> homozygous CF patients, and these effects persisted for 24 h after cysteamine withdrawal. Importantly, this cysteamine effect after washout was further sustained by the sequential administration of epigallocatechin gallate (EGCG), a green tea flavonoid, both <i>in vivo</i>, in mice, and <i>in vitro</i>, in primary epithelial cells from CF patients. In a pilot clinical trial involving 10 <i>F508del-CFTR</i> homozygous CF patients, the combination of cysteamine and EGCG restored BECN1, reduced SQSTM1 levels and improved CFTR function from nasal epithelial cells <i>in vivo</i>, correlating with a decrease of chloride concentrations in sweat, as well as with a reduction of the abundance of <i>TNF/TNF-alpha (tumor necrosis factor)</i> and <i>CXCL8</i> (<i>chemokine [C-X-C motif] ligand 8</i>) transcripts in nasal brushing and TNF and CXCL8 protein levels in the sputum. Altogether, these results suggest that optimal schedules of cysteamine plus EGCG might be used for the treatment of CF caused by the <i>F508del-CFTR</i> mutation.</p></div

    A linear programming-based method for job shop scheduling

    Get PDF
    We present a decomposition heuristic for a large class of job shop scheduling problems. This heuristic utilizes information from the linear programming formulation of the associated optimal timing problem to solve subproblems, can be used for any objective function whose associated optimal timing problem can be expressed as a linear program (LP), and is particularly effective for objectives that include a component that is a function of individual operation completion times. Using the proposed heuristic framework, we address job shop scheduling problems with a variety of objectives where intermediate holding costs need to be explicitly considered. In computational testing, we demonstrate the performance of our proposed solution approach
    corecore