Viser treff 121-140 av 316

    • Estimation of Blood Glucose Concentration During Endurance Sports 

      Sebastiani, Giovanni; Uteng, Stig; Godtliebsen, Fred; Polàk, Jan; Brož, Jan (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-21)
      In this paper, we describe a new statistical approach to estimate blood glucose concentration along time during endurance sports based on measurements of glucose concentration in subcutaneous interstitial tissue. The final goal is the monitoring of glucose concentration in blood to maximize performance in endurance sports. Blood glucose concentration control during and after aerobic physical ...
    • Hierarchical Representation Learning in Graph Neural Networks with Node Decimation Pooling 

      Bianchi, Filippo Maria; Grattarola, Daniele; Livi, Lorenzo; Alippi, Cesare (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-31)
      In graph neural networks (GNNs), pooling operators compute local summaries of input graphs to capture their global properties, and they are fundamental for building deep GNNs that learn hierarchical representations. In this work, we propose the Node Decimation Pooling (NDP), a pooling operator for GNNs that generates coarser graphs while preserving the overall graph topology. During training, the ...
    • A polymatroid approach to generalized weights of rank metric codes 

      Ghorpade, Sudhir R; Johnsen, Trygve (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-15)
      We consider the notion of a (<i>q,m)</i>-polymatroid, due to Shiromoto, and the more general notion of (<i>q,m</i>)-demi-polymatroids, and show how generalized weights can be defined for them. Further, we establish a duality for these weights analogous to Wei duality for generalized Hamming weights of linear codes. The corresponding results of Ravagnani for Delsarte rank metric codes, and Martínez-Peñas ...
    • Relative generalized Hamming weights of affine Cartesian codes 

      Datta, Mrinmoy (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-10)
      We explicitly determine all the relative generalized Hamming weights of affine Cartesian codes using the notion of footprints and results from extremal combinatorics. This generalizes the previous works on the determination of relative generalized Hamming weights of Reed–Muller codes by Geil and Martin, as well as the determination of all the generalized Hamming weights of the affine Cartesian codes ...
    • Integrability via Geometry: Dispersionless Differential Equations in Three and Four Dimensions 

      Calderbank, David M. J.; Kruglikov, Boris (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-25)
      We prove that the existence of a dispersionless Lax pair with spectral parameter for a nondegenerate hyperbolic second order partial differential equation (PDE) is equivalent to the canonical conformal structure defined by the symbol being Einstein–Weyl on any solution in 3D, and self-dual on any solution in 4D. The first main ingredient in the proof is a characteristic property for dispersionless ...
    • Homogeneous Levi non-degenerate hypersurfaces in C3 

      Doubrov, Boris; Medvedev, Alexandr; The, Dennis (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-09)
      We classify all (locally) homogeneous Levi non-degenerate real hypersurfaces in C<sup>3</sup> with symmetry algebra of dimension ≥6.
    • Blow-ups and infinitesimal automorphisms of CR-manifolds 

      Kruglikov, Boris (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-07)
      For a real-analytic connected CR-hypersurface M of CR-dimension n⩾1 having a point of Levi-nondegeneracy the following alternative is demonstrated for its symmetry algebra s=s(M): (i) either dims=n2+4n+3 and M is spherical everywhere; (ii) or dims⩽n2+2n+2+δ2,n and in the case of equality M is spherical and has fixed signature of the Levi form in the complement to its Levi-degeneracy locus. A version ...
    • Incorporating capture heterogeneity in the estimation of autoregressive coefficients of animal population dynamics using capture–recapture data 

      Nicolau, Pedro Guilherme; Sørbye, Sigrunn Holbek; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-31)
      Population dynamic models combine density dependence and environmental effects. Ignoring sampling uncertainty might lead to biased estimation of the strength of density dependence. This is typically addressed using state‐space model approaches, which integrate sampling error and population process estimates. Such models seldom include an explicit link between the sampling procedures and the true ...
    • Risk-Averse Food Recommendation Using Bayesian Feedforward Neural Networks for Patients with Type 1 Diabetes Doing Physical Activities 

      Ngo, Phuong; Tejedor Hernandez, Miguel Angel; Tayefi, Maryam; Chomutare, Taridzo; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-12)
      <p><i>Background.</i> Since physical activity has a high impact on patients with type 1 diabetes and the risk of hypoglycemia (low blood glucose levels) is significantly higher during and after physical activities, an automatic method to provide a personalized recommendation is needed to improve the blood glucose management and harness the benefits of physical activities. This paper aims to reduce ...
    • Generalized eigenvalue methods for Gaussian quadrature rules 

      Blekherman, Grigoriy; Kummer, Mario; Riener, Cordian; Schweighofer, Markus; Vinzant, Cynthia (Journal article; Tidsskriftartikkel; Peer reviewed, 2020)
      A quadrature rule of a measure <i>µ</i> on the real line represents a conic combination of finitely many evaluations at points, called nodes, that agrees with integration against <i>µ</i> for all polynomials up to some fixed degree. In this paper, we present a bivariate polynomial whose roots parametrize the nodes of minimal quadrature rules for measures on the real line. We give two symmetric ...
    • Condition Monitoring System for Internal Blowout Prevention (IBOP) in Top Drive Assembly System using Discrete Event Systems and Deep Learning Approaches 

      Noori, Nadia Saad; Waag, Tor Inge; Bianchi, Filippo Maria (Conference object; Konferansebidrag, 2020-07-19)
      <p>Offshore oil drilling is a complex process that requires careful coordination of hardware and control systems. Fault monitoring systems play an important role in such systems for safe and profitable operations. Thus, predictive maintenance and monitoring operating conditions of drilling systems are critical to the overall production cycle. In this paper, we are addressing the topic of condition ...
    • Statistical estimation of global surface temperature response to forcing under the assumption of temporal scaling 

      Myrvoll-Nilsen, Eirik; Sørbye, Sigrunn Holbek; Fredriksen, Hege-Beate; Rue, Håvard; Rypdal, Martin Wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-08)
      Reliable quantification of the global mean surface temperature (GMST) response to radiative forcing is essential for assessing the risk of dangerous anthropogenic climate change. We present the statistical foundations for an observation-based approach using a stochastic linear response model that is consistent with the long-range temporal dependence observed in global temperature variability. We ...
    • Spectral clustering with graph neural networks for graph pooling 

      Bianchi, Filippo Maria; Grattarola, Daniele; Alippi, Cesare (Conference object; Konferansebidrag, 2020)
      Spectral clustering (SC) is a popular clustering technique to find strongly connected communities on a graph. SC can be used in Graph Neural Networks (GNNs) to implement pooling operations that aggregate nodes belonging to the same cluster. However, the eigendecomposition of the Laplacian is expensive and, since clustering results are graph-specific, pooling methods based on SC must perform a ...
    • Reservoir computing approaches for representation and classification of multivariate time series 

      Bianchi, Filippo Maria; Scardapane, Simone; Løkse, Sigurd; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-29)
      Classification of multivariate time series (MTS) has been tackled with a large variety of methodologies and applied to a wide range of scenarios. Reservoir computing (RC) provides efficient tools to generate a vectorial, fixed-size representation of the MTS that can be further processed by standard classifiers. Despite their unrivaled training speed, MTS classifiers based on a standard RC ...
    • Validation of prediction models of severe disease course and non-achievement of remission in juvenile idiopathic arthritis part 2: Results of the Nordic model in the Canadian cohort 

      Henrey, Andrew; Rypdal, Veronika Gjertsen; Rypdal, Martin Wibe; Loughin, Thomas; Nordal, Ellen Berit; Guzman, Jaime (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-15)
      <b>Background</b> Validated clinical prediction models to identify children with poor prognosis at the time of juvenile idiopathic arthritis (JIA) diagnosis would be very helpful for tailoring treatments, and avoiding under- or over-treatment. Our objective was to externally validate Nordic clinical prediction models in Canadian patients with JIA. <b>Methods</b> We used data from 513 subjects ...
    • Homogeneous Levi non-degenerate hypersurfaces in C^3 

      Doubrov, Boris; Medvedev, Alexandr; The, Dennis (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-09)
      We classify all (locally) homogeneous Levi non-degenerate real hypersurfaces in C<sup>3</sup> with symmetry algebra of dimension ≥6.
    • Higher Weight Spectra of Veronese Codes 

      Johnsen, Trygve; Verdure, Hugues (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-18)
      We study q-ary linear codes C obtained from Veronese surfaces over finite fields.We show how one can find the higher weight spectra of these codes, or equivalently, the weight distribution of all extension codes of C over all field extensions of the ground field. Our methods will be a study of the Stanley-Reisner rings of a series of matroids associated to each code C.
    • Spatial trend analysis of gridded temperature data at varying spatial scales 

      Haug, Ola; Thorarinsdottir, Thordis Linda; Sørbye, Sigrunn Holbek; Franzke, Christian L.E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-28)
      Classical assessments of trends in gridded temperature data perform independent evaluations across the grid, thus, ignoring spatial correlations in the trend estimates. In particular, this affects assessments of trend significance as evaluation of the collective significance of individual tests is commonly neglected. In this article we build a space–time hierarchical Bayesian model for temperature ...
    • Symmetric Non-Negative Forms and Sums of Squares 

      Blekherman, Grigoriy; Riener, Cordian (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-21)
      We study symmetric non-negative forms and their relationship with symmetric sums of squares. For a fixed number of variables <i>n</i> and degree 2<i>d</i>, symmetric non-negative forms and symmetric sums of squares form closed, convex cones in the vector space of <i>n</i>-variate symmetric forms of degree 2<i>d</i>. Using representation theory of the symmetric group we characterize both cones in a ...
    • Food recommendation using machine learning for physical activities in patients with type 1 diabetes 

      Ngo, Phuong; Tayefi, Maryam; Nordsletta, Anne Torill; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      Physical activities have a significant impact on blood glucose homeostasis of patients with type 1 diabetes. Regular physical exercise provides many proven health benefits and is recommended as part of a healthy lifestyle. However, one of the main side effects of physical activities is hypoglycemia (low blood glucose). Fear of hypoglycemia generally leads to the patients not participating in ...