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  • Who benefits from postponement in multi-period supply channel optimization? 

    Azad Gholami, Reza; Sandal, Leif Kristoffer; Ubøe, Jan (Journal article; Peer reviewed, 2024)
    Duopolistic price-setting supply channels competing in a bilevel framework have been extensively studied in single-period (static) settings. However, such supply channels typically face uncertain and time-varying demand; ...
  • 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 ...
  • 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 ...
  • The highly nonlinear shallow water equation: local well-posedness, wave breaking data and non-existence of sech2 solutions 

    Hussien Elkhorbatly, Bashar (Journal article; Peer reviewed, 2024)
    In the context of the initial data and an amplitude parameter ε, we establish a local existence result for a highly nonlinear shallow water equation on the real line. This result holds in the space Hk as long as k > 5/2. ...
  • Limited Link of Common Blood Parameters with Tinnitus 

    Bulla, Jan; Brueggemann, Petra; Wrzosek, Małgorzata; Klasing, Sven; Boecking, Benjamin; Basso, Laura; Nyamaa, Amarjargal; Psatha, Stamatina; Rose, Matthias; Mazurek, Birgit (Journal article; Peer reviewed, 2023)
    Background: Tinnitus severity is generally assessed by psychometric and audiological instruments. However, no objective measure exists to evaluate the subjective discomfort and suffering caused by this hearing phenomenon. ...
  • Quantifying prior model complexity for subsurface reservoir models 

    Mioratina, Nomenjanahary Tanteliniaina; Oliver, Dean (Journal article; Peer reviewed, 2023)
    In Bayesian approaches to history matching for subsurface inference, the prior model specifies the uncertain model parameters and the joint probability of those parameters before incorporating production-related data. A ...
  • Rigorous derivation of some asymptotic models for free water surfaces and interfaces 

    Paulsen, Martin Oen (Doctoral thesis, 2024-04-26)
    Opprinnelsen til moderne matematisk hydrodynamikk kan spores tilbake til 1700-tallet. I 1757 publiserte Euler artikkelen der han introduserte ligninger, i dag kjent som Euler likningene, som kan beskrive væskedynamikk [31]. ...
  • The dissolution of a miscible drop rising or falling in another liquid at low Reynolds number 

    Nordbotten, Jan Martin; Mossige, Joachim (Journal article; Peer reviewed, 2023)
    “A basic and basically unsolved problem in fluid dynamics is to determine the evolution of rising bubbles and falling drops of one miscible liquid in another” [D. D. Joseph and Y. Y. Renardy, Fundamentals of Two-Fluid ...
  • The weight spectrum of two families of Reed-Muller codes 

    Carlet, Claude Michael; Solé, Patrick (Journal article; Peer reviewed, 2023)
    We determine the weight spectra of the Reed-Muller codes RM (m− 3, m) for m ≥ 6 and RM (m − 4, m) for m ≥ 8. The technique used is induction on m, using that the sum of two weights in RM (r −1, m−1) is a weight in RM (r, ...
  • PoroTwin: A Digital Twin for a FluidFlower Rig 

    Keilegavlen, Eirik; Fonn, Eivind; Johannessen, Kjetil Andre; Eikehaug, Kristoffer; Both, Jakub Wiktor; Fernø, Martin; Kvamsdal, Trond; Rasheed, Adil; Nordbotten, Jan Martin (Journal article; Peer reviewed, 2023)
    We present a framework for integrated experiments and simulations of tracer transport in heterogeneous porous media using digital twin technology. The physical asset in our setup is a meter-scale FluidFlower rig. The digital ...
  • Count time series with application to corporate defaults 

    Mohammed, Elyas Dawud (Master thesis, 2020-06-12)
  • Simulation of Reactive Transport in Fractured Porous Media 

    Banshoya, Shin Irgens; Berre, Inga; Keilegavlen, Eirik (Journal article; Peer reviewed, 2023)
    Numerical simulations of reactive transport in fractured porous media require the solution of coupled physical and chemical processes that depend on the fractures. Such coupled processes are described by a system of nonlinear ...
  • A TMB Approach to Study Spatial Variation in Weather-Generated Claims in Insurance 

    Thorsen, Ingrid Sandvig; Støve, Bård; Skaug, Hans Julius (Journal article; Peer reviewed, 2023)
    In this paper, we use TMB to study spatial variation in weather-generated claims in insurance. Our motivation is twofold. By comparing with INLA, we first find that TMB is a robust and efficient approach to deal with spatial ...
  • Tinnitus Is Marginally Associated with Body Mass Index, Heart Rate and Arterial Blood Pressure: Results from a Large Clinical Sample 

    Langguth, Berthold; Bulla, Jan; Fischer, Beate; Baurecht, Hansjoerg; Schecklmann, Martin; Marcrum, Steven C.; Vielsmeier, Veronika (Journal article; Peer reviewed, 2023)
    Introduction: This study aimed to explore whether body mass index (BMI), systolic blood pressure (RR syst), diastolic blood pressure (RR diast) or heart rate (HR) are associated with tinnitus status and/or severity. Methods: ...
  • Screening for Circulating Inflammatory Proteins Does Not Reveal Plasma Biomarkers of Constant Tinnitus 

    Cederroth, Christopher R.; Hong, Mun-Gwan; Freydin, Maxim B.; Edvall, Niklas K.; Trpchevska, Natalia; Jarach, Carlotta; Schlee, Winfried; Schwenk, Jochen M.; Lopez-Escamez, Jose-Antonio; Gallus, Silvano; Canlon, Barbara; Bulla, Jan; Williams, Frances M. K. (Journal article; Peer reviewed, 2023)
    Background and Objective Tinnitus would benefit from an objective biomarker. The goal of this study is to identify plasma biomarkers of constant and chronic tinnitus among selected circulating inflammatory proteins. ...
  • Computational issues in parameter estimation for hidden Markov models with template model builder 

    Bacri, Timothee Raphael Ferdinand; Berentsen, Geir Drage; Bulla, Jan; Støve, Bård (Journal article; Peer reviewed, 2023)
    A popular way to estimate the parameters of a hidden Markov model (HMM) is direct numerical maximization (DNM) of the (log-)likelihood function. The advantages of employing the TMB [Kristensen K, Nielsen A, Berg C, et al. ...
  • Particle Trajectories in Long Wave Models 

    Ige, Olufemi Elijah (Doctoral thesis, 2024-04-05)
    Atferden og mønstrene til partikkelbaner i bølgebevegelser i grunt vann har blitt studert av forskere i flere tiår, spesielt har egenskapene til strømmer under overflatebølger i grunt vann blitt studert ved bruk av matematiske ...
  • On coupled envelope evolution equations in the Hamiltonian theory of nonlinear surface gravity waves 

    Li, Yan (Journal article; Peer reviewed, 2023)
    This paper presents a novel theoretical framework in the Hamiltonian theory of nonlinear surface gravity waves. The envelope of surface elevation and the velocity potential on the free water surface are introduced in the ...
  • The influence of directional spreading on rogue waves triggered by abrupt depth transitions 

    Tang, Tianning; Moss, Charlotte; Draycott, Samuel; Bingham, Harry B.; Van Den Bremer, Ton S.; Li, Yan; Adcock, Thomas A.A. (Journal article; Peer reviewed, 2023)
    An increased number of rogue waves, relative to standard distributions, can be induced by unidirectional waves passing over abrupt decreases in water depth. We investigate this phenomenon in a more general setting of ...
  • Coupled effects of wave and depth-dependent current interaction on loads on a bottom-fixed vertical slender cylinder 

    Xin, Zirui; Li, Xin; Li, Yan (Journal article; Peer reviewed, 2023)
    The coupled effects of waves and a subsurface current on the hydrodynamic loads on offshore slender structures in coastal water regions have been examined in this paper, especially the coupling of the weak nonlinearity of ...

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