• Classification of simply-transitive Levi non-degenerate hypersurfaces in C^3 

      Doubrov, Boris; Merker, Joël; The, Dennis (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-24)
      Holomorphically homogeneous Cauchy–Riemann (CR) real hypersurfaces <i>M<i/><sup>3</sup>⊂C<sup>2</sup> were classified by Élie Cartan in 1932. In the next dimension, we complete the classification of simply-transitive Levi non-degenerate hypersurfaces <i>M<i/><sup>5</sup>⊂C<sup>3</sup> using a novel Lie algebraic approach independent of any earlier classifications of abstract Lie algebras. Central ...
    • Climate variability in the subarctic area for the last 2 millennia 

      Nicolle, Marie; Debret, Maxime; Massei, Nicolas; Colin, Christophe; de Vernal, Anne; Divine, Dmitry V; Werner, Johannes; Hormes, Anne; Korhola, Atte; Linderholm, Hans W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-25)
      To put recent climate change in perspective, it is necessary to extend the instrumental climate records with proxy data from paleoclimate archives. Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many types of proxy data archived in the ...
    • Clustering and climate associations of Kawasaki Disease in San Diego County suggest environmental triggers 

      Rypdal, Martin wibe; Rypdal, Veronika Gjertsen; Burney, Jennifer A.; Cayan, Daniel; Bainto, Emelia; Skochko, Shannon; Tremoulet, Adriana H.; Creamean, Jessie; Shimizu, Chisato; Kim, Ji-Hoon; Burns, Jane C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-12)
      Kawasaki Disease (KD) is the most common cause of pediatric acquired heart disease, but its etiology remains unknown. We examined 1164 cases of KD treated at a regional children’s hospital in San Diego over a period of 15 years and uncovered novel structure to disease incidence. KD cases showed a well-defined seasonal variability, but also clustered temporally at much shorter time scales (days to ...
    • Codes from symmetric polynomials 

      Johnsen, Trygve; Datta, Mrinmoy (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-10)
      We define and study a class of Reed–Muller type error-correcting codes obtained from elementary symmetric functions in finitely many variables. We determine the code parameters and higher weight spectra in the simplest cases.
    • Coloring the Voronoi tessellation of lattices 

      Dutour Sikirić, Mathieu; Madore, David A.; Moustrou, Philippe; Vallentin, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-03)
      In this paper we define the chromatic number of a lattice: It is the least number of colors one needs to color the interiors of the cells of the Voronoi tessellation of a lattice so that no two cells sharing a facet are of the same color. We compute the chromatic number of the root lattices, their duals, and of the Leech lattice, we consider the chromatic number of lattices of Voronoi’s first ...
    • Comment on "Scaling regimes and linear/nonlinear responses of last millennium climate to volcanic and solar forcing" by S. Lovejoy and C. Varotsos (2016) 

      Rypdal, Kristoffer; Rypdal, Martin Wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-13)
      Lovejoy and Varotsos (2016) (L&V) analyse the temperature response to solar, volcanic, and solar plus volcanic forcing in the Zebiak–Cane (ZC) model, and to solar and solar plus volcanic forcing in the Goddard Institute for Space Studies (GISS) E2-R model. By using a simple wavelet filtering technique they conclude that the responses in the ZC model combine subadditively on timescales from 50 to ...
    • Comparison of computer systems and ranking criteria for automatic melanoma detection in dermoscopic images 

      Møllersen, Kajsa; Zortea, Maciel; Schopf, Thomas Roger Griesbeck; Kirchesch, Herbert M.; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-21)
      Melanoma is the deadliest form of skin cancer, and early detection is crucial for patient survival. Computer systems can assist in melanoma detection, but are not widespread in clinical practice. In 2016, an open challenge in classification of dermoscopic images of skin lesions was announced. A training set of 900 images with corresponding class labels and semi-automatic/manual segmentation masks ...
    • Compatibility, multi-brackets and integrability of systems of PDEs 

      Kruglikov, Boris; Lychagin, Valentin V. (Journal article; Tidsskriftartikkel; Peer reviewed, 2008-02-20)
      We establish an efficient compatibility criterion for a system of generalized complete intersection type in terms of certain multi-brackets of differential operators. These multi-brackets generalize the higher Jacobi- Mayer brackets, important in the study of evolutionary equations and the integrability problem. We also calculate Spencer δ-cohomology of generalized complete intersections and ...
    • Comprehensive uncertainty estimation of the timing of Greenland warmings in the Greenland ice core records 

      Myrvoll-Nilsen, Eirik; Riechers, Keno; Rypdal, Martin Wibe; Boers, Niklas (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-20)
      Paleoclimate proxy records have non-negligible uncertainties that arise from both the proxy measurement and the dating processes. Knowledge of the dating uncertainties is important for a rigorous propagation to further analyses, for example, for identification and dating of stadial– interstadial transitions in Greenland ice core records during glacial intervals, for comparing the variability in ...
    • Computer-aided decision support for melanoma detection applied on melanocytic and non-melanocytic skin lesions: a comparison of two systems based on automatic analysis of dermoscopic images 

      Møllersen, Kajsa; Kirchesch, Herbert M.; Zortea, Maciel; Schopf, Thomas Roger Griesbeck; Hindberg, Kristian; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Commercially available clinical decision support systems (CDSSs) for skin cancer have been designed for the detection of melanoma only. Correct use of the systems requires expert knowledge, hampering their utility for nonexperts. Furthermore, there are no systems to detect other common skin cancer types, that is, nonmelanoma skin cancer (NMSC). As early diagnosis of skin cancer is essential, there ...
    • Computing critical points for invariant algebraic systems 

      Faugère, Jean-Charles; Labahn, George; Safey El Din, Mohab; Schost, Éric; Vu, Thi Xuan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-24)
    • 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 ...
    • Conformal differential invariants 

      Kruglikov, Boris (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-27)
      We compute the Hilbert polynomial and the Poincar´e function counting the number of fixed jet-order differential invariants of conformal metric structures modulo local diffeomorphisms, and we describe the field of rational differential invariants separating generic orbits of the diffeomorphism pseudogroup action. This resolves the local recognition problem for conformal structures.
    • Constraining two climate field reconstruction methodologies over the North Atlantic realm using pseudo-proxy experiments 

      Nilsen, Tine; Talento, Stefanie; Werner, Johannes P (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-06)
      This study presents pseudo-proxy experiments to quantify the reconstruction skill of two climate field reconstruction methodologies for a marine proxy network subject to age uncertainties. The BARCAST methodology (Bayesian Algorithm for Reconstructing Climate Anomalies in Space and Time) is tested for sea surface temperature (SST) reconstruction for the first time over the northern North Atlantic ...
    • Constructing a partially transparent computational boundary for UPPE using leaky modes 

      Juhász, Dávid; Jakobsen, Per Kristen (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-19)
      In this paper, we introduce a method for creating a transparent computational boundary for the simulation of unidirectional propagation of optical beams and pulses using leaky modes. The key element of the method is the introduction of an artificial-index material outside a chosen computational domain and utilization of the quasi-normal modes associated with such artificial structure. The method is ...
    • Continuum mechanics of media with inner structures 

      Duyunova, Anna; Lychagin, Valentin; Tychkov, Sergey (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-05)
      We propose a geometrical approach to the mechanics of continuous media equipped with inner structures and give the basic (Navier–Stokes, mass conservation and energy conservation) equations of their motion.
    • Control of Blood Glucose for Type-1 Diabetes by Using Reinforcement Learning with Feedforward Algorithm 

      Ngo, Phuong; Wei, Susan; Holubova, Anna; Muzik, Jan; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-30)
      <p><i>Background</i>: Type-1 diabetes is a condition caused by the lack of insulin hormone, which leads to an excessive increase in blood glucose level. The glucose kinetics process is difficult to control due to its complex and nonlinear nature and with state variables that are difficult to measure.</p> <p><i>Methods</i>: This paper proposes a method for automatically calculating the basal and ...
    • Convergence and completeness for square-well Stark resonant state expansions 

      Juhász, David; Kolesik, Miro; Jakobsen, Per (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-02)
      In this paper, we investigate the completeness of the Stark resonant states for a particle in a square-well potential. We find that the resonant state expansions for target functions converge inside the potential well and that the existence of this convergence does not depend on the depth of the potential well, <i>V</i><sub>0</sub>. By analyzing the asymptotic form of the terms in these expansions, ...
    • COPD in primary lung cancer patients: prevalence and mortality 

      Ytterstad, Elinor; Moe, Per Christian; Hjalmarsen, Audhild (Journal article; Peer reviewed; Tidsskriftartikkel, 2016-03-23)
      Background: Previous studies have relied on international spirometry criteria to diagnose COPD in patients with lung cancer without considering the effect lung cancer might have on spirometric results. The aim of this study was to examine the prevalence of COPD and emphysema at the time of primary lung cancer diagnosis and to examine factors associated with survival. Materials and methods: Medical ...
    • Cosheaves 

      Prasolov, Andrei (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-21)
      The categories pCS(X,Pro(k)) of precosheaves and CS(X,Pro(k)) of cosheaves on a small Grothendieck site X, with values in the category Pro(k) of prok-modules, are constructed. It is proved that pCS(X,Pro(k)) satisfies the AB4 and AB5* axioms, while CS(X,Pro(k)) satisfies AB3 and AB5*. Homology theories for cosheaves and precosheaves, based on quasi-projective resolutions, are constructed and investigated.