• Reiterated homogenization of nonlinear monotone operators in a general deterministic setting 

      Lukkassen, Dag; Nguetseng, Gabriel; Nnang, Hubert; Wall, Peter (Journal article; Peer reviewed, 2009)
      We study reiterated homogenization of a nonlinear non-periodic elliptic differential operator in a general deterministic setting as opposed to the usual stochastic setting. Our approach proceeds from an appropriate notion of convergence termed reiterated Σ-convergence. A general deterministic homogenization theorem is proved and several concrete examples are studied under various structure hypotheses ...
    • Cascade-Based Controlled Attitude Synchronization and Tracking of Spacecraft in Leader-Follower Formation 

      Schlanbusch, Rune; Nicklasson, Per Johan; Loria, Antonio (Journal article; Peer reviewed, 2011)
    • Atmospheric icing on wind turbines : Modeling and consequences for energy production 

      Homola, Matthew Carl (Doctoral thesis; Doktorgradsavhandling, 2011)
    • Numerical Study of Atmospheric Ice Accretion on Various Geometric Cross-sections 

      Virk, Muhammad Shakeel (Journal article; Peer reviewed, 2011)
    • On heat conduction in domains containing noncoaxial cylinders 

      Lukkassen, Dag; Meidell, Annette (Journal article; Peer reviewed, 2012)
      We consider heat conduction in domains containing noncoaxial cylinders. In particular, we present some regularity results for the solution and consider criteria which ensure the single valueness of the corresponding complex potential. Examples are discussed. In addition, we present some classes of cases where the parameters describing the solution are rational. Alternative ways of calculating the ...
    • Steklov Problems in Perforated Domains with a Coefficient of Indefinite Sign 

      Piatnitski, Andrey L.; Piat, Valeria C.; Nazarov, Sergey S. (Journal article; Peer reviewed, 2012)
    • An Empirical Study on the Impact of Cultural Types on Resources Integration Model 

      Solvang, Wei Deng; Zhan, Yan; Lu, Jiansha (Journal article; Peer reviewed, 2012)
      From the perspective of Resource-based Theory (RBT), organizational culture can be a source of sustained competitive advantage. And resources integration models, divided by property rights of resource, not firm boundary, as internal and external resources integration models, are presented as being specific in different cultural contexts. However, the litera- ture review shows the absences of an ...
    • Quantitative analysis of accuracy of voidage computations in CFD-DEM Simulations 

      Khawaja, Hassan Abbas; Scott, Stuart A.; Virk, Muhammad Shakeel; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
    • Control of rigid bodies : with applications to leader-follower spacecraft formations 

      Schlanbusch, Rune (Doctoral thesis; Doktorgradsavhandling, 2012)
    • Exact Asymptotic Expansion of Singular Solutions for the (2+1)-D Protter Problem 

      Dechevski, Lubomir T (Journal article; Peer reviewed, 2012)
    • Weighted Hardy Operators in Complementary Morrey Spaces 

      Lukkassen, Dag; Persson, Lars Erik; Samko, Stefan (Journal article; Peer reviewed, 2012)
    • Weighted Hardy-Type Inequalities in Variable Exponent Morrey-Type Spaces 

      Lukkassen, Dag; Persson, Lars Erik; Samko, Stefan; Wall, Peter (Journal article; Peer reviewed, 2013)
      We study the p(.) -> q(.) boundedness of weighted multidimensional Hardy-type operators H-w(alpha(.)) and H-w(alpha(.)) of variable order alpha(x), with radial weight w(vertical bar x vertical bar), from a variable exponent locally generalized Morrey space L-p(.),L-phi(.)(R-n, w) to another L-q(.),L-psi(.)(R-n, w). The exponents are assumed to satisfy the decay condition at the origin and infinity. ...
    • Ubemannede flaksende mikrofly 

      Oland, Espen (Journal article, 2013)
    • Atmospheric ice monitoring system operation at Remote locations in cold region 

      Virk, Muhammad Shakeel; Rashid, Taimur; Mustafa, Mohamad Y (Journal article; Peer reviewed, 2013)
      The problems encountered in installation, maintenance and operations of equipment in the cold climate regions are far more complicated than others. The contributing factors and problems that can affect the system operation and performance should be identified, assessed and focused within well-defined parameters before its installation in cold climate regions. The harsh cold environment, could not ...
    • Underactuated Waypoint Tracking of a Fixed-Wing UAV 

      Oland, Espen; Schlanbusch, Rune; Kristiansen, Raymond (Journal article; Peer reviewed, 2013)
      In this paper a new method of performing waypoint tracking is shown for underactuated fixed-wing UAVs. The position error can be mapped onto the desired axis using a desired rotation matrix, while the velocity error can be mapped to the desired axis using a desired angular velocity. With all errors defined along one axis, the tracking problem is easily solved using only one thruster. A velocity ...
    • Real-Time Particle Tracking using a Formation of UAVs 

      Oland, Espen; Kristiansen, Raymond (Journal article; Peer reviewed, 2013)
      In this paper the problem of real-time particle tracking is studied. Using sensor measurements, a formation of UAVs autonomously find the closest point with high particle density where they enter a holding pattern. After converging to the holding pattern, one UAV will remain, while the rest will go looking for other maxima. To avoid collisions between the UAVs during the mission, a controller is ...
    • Underactuated Control of Quadrotors with Collision Avoidance 

      Oland, Espen; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Peer reviewed, 2013)
      In this paper a saturated controller is derived that solves the translational control problem for underactuated quadrotors. The controller is applied to multiple quadrotors during a formation reconfiguration where the quadrotors move from an initial position to a desired position. The null-space-based behavioral control method is a popular method for avoiding collisions between mobile agents, and ...
    • Experimental study of relative permittivity of atmospheric ice 

      Bhattu, Shravan K; Mughal, Umair Najeeb; Virk, Muhammad Shakeel (Journal article; Peer reviewed, 2013-01-01)
      Atmospheric icing on onshore and offshore structures is problematic, if we don’t detect and remove it. Despite of various ice detection techniques, capacitor based ice sensing technique is interesting one, as it is based on dielectric properties of material. This technique of measuring icing event is simple and cost- effective. Based on the dielectric concept, an experi mental ...
    • Atmospheric Icing Sensors - Capacitive Techniques 

      Mughal, Umair Najeeb; Virk, Muhammad Shakeel (Peer reviewed, 2013-01-22)
      The application of capacitive sensing technique is widely distributed in different physical domains primarily because of the diversity in dielectric permittivity and due to its minimum loading error and inertial effects. Atmospheric ice is a complex mixture of water, ice and air which is reflected in its complex dielectric constant. There are many existing atmospheric icing sensors but only few are ...
    • Numerical Study of Atmospheric Icing on Non Rotating Circular Cylinders in Tandem Arrangement 

      Virk, Muhammad Shakeel (Journal article; Peer reviewed, 2013-03-01)
      Numerical study of atmospheric ice accretion on two non-rotating circular cylinders in tandem arrangement was carried out at different operating and geometric conditions. To validate the numerical model, initially the results of ice accretion on single circular cylinder were compared with the experimental data obtained from CIGELE atmospheric icing research wind tunnel (CAIRWT) [1, 2]. A good agreement ...