• Four definitions of magnetic permeability for periodic metamaterials 

      Skaar, Johannes; Hågenvik, Hans Olaf; Dirdal, Christopher Andrew (Journal article; Peer reviewed, 2019)
      We state and compare four different definitions of magnetic permeability for periodic, artificial media, or metamaterials. The connections among them, and properties in general, are discussed in detail, including causality, ...
    • Higher order multipoles in metamaterial homogenization 

      Dirdal, Christopher Andres; Hågenvik, Hans Olaf; Haave, Haakon Aamodt; Skaar, Johannes (Journal article; Peer reviewed, 2018)
      The higher order multipoles above the electric quadrupole are commonly neglected in metamaterial homogenization. We show that they nevertheless can be significant when the second-order spatial dispersive effects, such as ...
    • Nonconvex Environmental Constraints in Hydropower Scheduling 

      Helseth, Arild; Mo, Birger; Hågenvik, Hans Olaf (Chapter, 2020)
      Environmental constraints in hydropower systems serve to ensure sustainable use of water resources. Through accurate treatment in hydropower scheduling, one seeks to respect such constraints in the planning phase while ...