Blar i Department of Mathematics på utgivelsesdato

Viser treff 61-80 av 966

    • Symmetric waves are traveling waves of some shallow water scalar equations 

      Hussien Elkhorbatly, Bashar (Journal article; Peer reviewed, 2023)
      Following a straightforward proof for symmetric solutions to be traveling waves by Pei (Exponential decay and symmetry of solitary waves to Degasperis-Procesi equation. Journal of Differential Equations. 2020;269(10):7730-7749), ...

    • The aromatic bicomplex for the description of divergence-free aromatic forms and volume-preserving integrators 

      Laurent, Adrien Ange Andre; Mclachlan, Robert I.; Munthe-Kaas, Hans Zanna; Verdier, Olivier Philippe Paul (Journal article; Peer reviewed, 2023)
      Aromatic B-series were introduced as an extension of standard Butcher-series for the study of volume-preserving integrators. It was proven with their help that the only volume-preserving B-series method is the exact flow ...

    • Menopausal hormone therapy, oral contraceptives and risk of chronic low back pain: the HUNT Study 

      Heuch, Ingrid; Heuch, Ivar; Hagen, Knut; Storheim, Kjersti; Zwart, John Anker Henrik (Journal article; Peer reviewed, 2023)
      Background There are indications that use of menopausal hormone therapy (MHT) and oral contraceptives (OC) increases the risk of low back pain (LBP), with higher oestrogen levels involved in the underlying mechanisms. The ...

    • The FluidFlower Validation Benchmark Study for the Storage of CO2 

      Flemisch, Bernd; Nordbotten, Jan Martin; Fernø, Martin; Juanes, Ruben; Both, Jakub Wiktor; Class, Holger; Delshad, Mojdeh; Doster, Florian; Ennis-King, Jonathan; Franc, Jacques; Geiger, Sebastian; Gläser, Dennis; Green, Christopher; Gunning, James; Hajibeygi, Hadi; Jackson, Samuel J.; Jammoul, Mohamad; Karra, Satish; Li, Jiawei; Matthäi, Stephan K.; Miller, Terry; Shao, Qi; Spurin, Catherine; Stauffer, Philip; Tchelepi, Hamdi; Tian, Xiaoming; Viswanathan, Hari; Voskov, Denis; Wang, Yuhang; Wapperom, Michiel; Wheeler, Mary F.; Wilkins, Andrew; Youssef, AbdAllah A.; Zhang, Ziliang (Journal article; Peer reviewed, 2023)
      Successful deployment of geological carbon storage (GCS) requires an extensive use of reservoir simulators for screening, ranking and optimization of storage sites. However, the time scales of GCS are such that no sufficient ...

    • Elliptic curves, ACM bundles and Ulrich bundles on prime Fano threefolds 

      Ciliberto, Ciro; Flamini, Flaminio; Knutsen, Andreas Leopold (Journal article; Peer reviewed, 2023)
      Let X be any smooth prime Fano threefold of degree 2g−2 in Pg+1 , with g ∈ {3, . . . , 10, 12}. We prove that for any integer d satisfying ⌊ g+3 2 ⌋ d g+3 the Hilbert scheme parametriz- ing smooth irreducible elliptic ...

    • Marginalized iterative ensemble smoothers for data assimilation 

      Stordal, Andreas Størksen; Lorentzen, Rolf Johan; Fossum, Kristian (Journal article; Peer reviewed, 2023)
      Data assimilation is an important tool in many geophysical applications. One of many key elements of data assimilation algorithms is the measurement error that determines the weighting of the data in the cost function to ...

    • Covering tour problem with varying coverage: Application to marine environmental monitoring 

      Torabi, Parisa; Oleynik, Anna; Hemmati, Ahmad; Alendal, Guttorm (Journal article; Peer reviewed, 2023)
      In this paper, we present a novel variant of the Covering Tour Problem (CTP), called the Covering Tour Problem with Varying Coverage (CTP-VC). We consider a simple graph 𝐺 = (𝑉 ,𝐸), with a measure of importance assigned ...

    • Machine learning in marine ecology: an overview of techniques and applications 

      Rubbens, Peter; Brodie, Stephanie; Cordier, Tristan; Desto Barcellos, Diogo; DeVos, Paul; Fernandes-Salvador, Jose A; Fincham, Jennifer; Gomes, Alessandra; Handegard, Nils Olav; Howell, Kerry L.; Jamet, Cédric; Kartveit, Kyrre Heldal; Moustahfid, Hassan; Parcerisas, Clea; Politikos, Dimitris V.; Sauzède, Raphaëlle; Sokolova, Maria; Uusitalo, Laura; Van den Bulcke, Laure; van Helmond, Aloysius; Watson, Jordan T.; Welch, Heather; Beltran-Perez, Oscar; Chaffron, Samuel; Greenberg, David S.; Kühn, Bernhard; Kiko, Rainer; Lo, Madiop; Lopes, Rubens M.; Möller, Klas Ove; Michaels, William; Pala, Ahmet; Romagnan, Jean-Baptiste; Schuchert, Pia; Seydi, Vahid; Villasante, Sebastian; Malde, Ketil; Irisson, Jean-Olivier (Journal article; Peer reviewed, 2023)
      Machine learning covers a large set of algorithms that can be trained to identify patterns in data. Thanks to the increase in the amount of data and computing power available, it has become pervasive across scientific ...

    • Numerical Treatment of State-Dependent Permeability in Multiphysics Problems 

      Stefansson, Ivar; Keilegavlen, Eirik (Journal article; Peer reviewed, 2023)
      Constitutive laws relating fluid potentials and fluxes in a nonlinear manner are common in several porous media applications, including biological and reactive flows, poromechanics, and fracture deformation. Compared to ...

    • DarSIA: An Open-Source Python Toolbox for Two-Scale Image Processing of Dynamics in Porous Media 

      Nordbotten, Jan Martin; Benali, Benyamine; Both, Jakub Wiktor; Brattekås, Bergit; Storvik, Erlend; Fernø, Martin (Journal article; Peer reviewed, 2023)
      Understanding porous media flow is inherently a multi-scale challenge, where at the core lies the aggregation of pore-level processes to a continuum, or Darcy-scale, description. This challenge is directly mirrored in image ...

    • Ulrich bundles on a general blow-up of the plane 

      Ciliberto, Ciro; Flamini, Flaminio; Knutsen, Andreas Leopold (Journal article; Peer reviewed, 2023)
      We prove that on X n , the plane blown-up at n very general points, there are Ulrich line bundles with respect to a line bundle corresponding to curves of degree m passing simply through the n blown-up points, with m ≤ 2√n ...

    • Irreducible unirational and uniruled components of moduli spaces of polarized Enriques surfaces 

      Ciliberto, Ciro; Dedieu, Thomas; Galati, Concettina; Knutsen, Andreas Leopold (Journal article; Peer reviewed, 2023)
      We prove that infinitely many irreducible components of the moduli space of polarized Enriques surfaces are unirational (resp. uniruled), characterizing them in terms of decompo- sitions of the polarization as an effective ...

    • Nonemptiness of severi varieties on enriques surfaces 

      Ciliberto, Ciro; Dedieu, Thomas; Galati, Concettina; Knutsen, Andreas Leopold (Journal article; Peer reviewed, 2023)
      Let (S,L) be a general polarised Enriques surface, with L not numerically 2-divisible. We prove the existence of regular components of all Severi varieties of irreducible nodal curves in the linear system |L| , that is, ...

    • Addressing class imbalance in deep learning for acoustic target classification 

      Pala, Ahmet; Oleynik, Anna; Utseth, Ingrid; Handegard, Nils Olav (Journal article; Peer reviewed, 2023)
      Acoustic surveys provide important data for fisheries management. During the surveys, ship-mounted echo sounders send acoustic signals into the water and measure the strength of the reflection, so-called backscatter. ...

    • Cellular and environmental dynamics influence species-specific extents of organelle gene retention 

      Garcia Pascual, Belen; Nordbotten, Jan Martin; Johnston, Iain (Journal article; Peer reviewed, 2023)
      Mitochondria and plastids rely on many nuclear-encoded genes, but retain small subsets of the genes they need to function in their own organelle DNA (oDNA). Different species retain different numbers of oDNA genes, and the ...

    • Perfusion estimation using synthetic MRI-based measurements and a porous media flow model 

      Lorentzen, Rolf Johan; Nævdal, Geir; Sævareid, Ove; Hodneland, Erlend; Hanson, Erik Andreas; Munthe-Kaas, Antonella Zanna (Journal article; Peer reviewed, 2023)
      The measurement of perfusion and filtration of blood in biological tissue give rise to important clinical parameters used in diagnosis, follow-up, and therapy. In this paper, we address techniques for perfusion analysis ...

    • Local Gaussian Cross-Spectrum Analysis 

      Jordanger, Lars Arne; Tjøstheim, Dag Bjarne (Journal article; Peer reviewed, 2023)
      The ordinary spectrum is restricted in its applications, since it is based on the second-order moments (auto- and cross-covariances). Alternative approaches to spectrum analysis have been investigated based on other measures ...

    • MRI-based radiomic signatures for pretreatment prognostication in cervical cancer 

      Wagner-Larsen, Kari Strøno; Hodneland, Erlend; Fasmer, Kristine Eldevik; Lura, Njål; Woie, Kathrine; Bertelsen, Bjørn; Salvesen, Øyvind Olav; Halle, Mari Kyllesø; Smit, Noeska Natasja; Krakstad, Camilla; Haldorsen, Ingfrid S. (Journal article; Peer reviewed, 2023)
      Background Accurate pretherapeutic prognostication is important for tailoring treatment in cervical cancer (CC). Purpose To investigate whether pretreatment MRI-based radiomic signatures predict disease-specific ...

    • Some recent trends in embeddings of time series and dynamic networks 

      Tjøstheim, Dag Bjarne; Jullum, Martin; Løland, Anders (Journal article; Peer reviewed, 2023)
      We give a review of some recent developments in embeddings of time series and dynamic networks. We start out with traditional principal components and then look at extensions to dynamic factor models for time series. Unlike ...

    • Statistical Embedding: Beyond Principal Components 

      Tjøstheim, Dag Bjarne; Jullum, Martin; Løland, Anders (Journal article; Peer reviewed, 2023)
      There has been an intense recent activity in embedding of very high-dimensional and nonlinear data structures, much of it in the data science and machine learning literature. We survey this activity in four parts. In the ...