Browsing Fakultet for ingeniørvitenskap og teknologi by Issue Date

Now showing items 1-20 of 740

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

      Lukkassen, Dag; Nguetseng, Gabriel; Nnang, Hubert; Wall, Peter (Journal article; Peer reviewed; Tidsskriftartikkel, 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 ...

    • Atmospheric icing on wind turbines : Modeling and consequences for energy production 

      Homola, Matthew Carl (Doctoral thesis; Doktorgradsavhandling, 2011)

    • Cascade-Based Controlled Attitude Synchronization and Tracking of Spacecraft in Leader-Follower Formation 

      Schlanbusch, Rune; Nicklasson, Per Johan; Loria, Antonio (Journal article; Peer reviewed; Tidsskriftartikkel, 2011)

    • Numerical Study of Atmospheric Ice Accretion on Various Geometric Cross-sections 

      Virk, Muhammad Shakeel (Journal article; Peer reviewed; Tidsskriftartikkel, 2011)

    • Ant colony optimization and analysis of time step resolution in transmission expansion computations for wind power integration 

      Fuchs, Ida; Gjengedal, Terje (Chapter; Bokkapittel, 2011)
      This paper investigates the necessary time step resolution in a transmission expansion planning algorithm based on ant colony optimization. A maximal and efficient wind power integration is the main motivation for the grid expansion, which requires a planning tool dealing with wind energy fluctuations. For the analysis a power system model for the Nordic area is used, including a wind power ...

    • Cascade-Based Controlled Attitude Synchronization and Tracking of Spacecraft in Leader-Follower Formation 

      Schlanbusch, Rune; Loria, Antonio; Nicklasson, Per Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-05-05)
      We propose controllers for leader-follower attitude synchronization of spacecraft formations in the presence of disturbances, that is, the leader spacecraft is controlled to follow a given reference, while a follower spacecraft is controlled to synchronize its motion with the leader’s. In the ideal disturbance-free scenario, we show that synchronization takes place asymptotically. Moreover, we ...

    • Atmospheric Ice Accretion Measurement Techniques 

      Virk, Muhammad Shakeel; Mustafa, Mohamad Y; Hamdan, Qusai-Al (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-09-30)
      Atmospheric icing on structures has proven to be an area of concern in many cold climate geographical regions like arctic and alpine. Difficulties encountered by the communication, construction and power industries in these areas are the subject of intense investigations for researchers from decades. Three main methods of investigation are generally employed by researchers to study atmospheric ice ...

    • Fluid-structure Interaction for Water Hammers Effects in Petroleum and Nuclear Plants 

      Messahel, Ramzi; Cohen, B; Souli, M; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-12-31)
      Fluid-Structure Interaction (FSI) becomes more and more the focus of computational engineering in Petroleum and Nuclear Industry in the last years. These problems are computer time consuming and require new stable and accurate coupling algorithms to be solved. For the last decades, the new development of coupling algorithms, and the increasing of computer performance have allowed to solve some ...

    • Exact Asymptotic Expansion of Singular Solutions for the (2+1)-D Protter Problem 

      Dechevski, Lubomir T (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)

    • Steklov Problems in Perforated Domains with a Coefficient of Indefinite Sign 

      Piatnitski, Andrey L.; Piat, Valeria C.; Nazarov, Sergey S. (Journal article; Tidsskriftartikkel; 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; Tidsskriftartikkel; 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 ...

    • On heat conduction in domains containing noncoaxial cylinders 

      Lukkassen, Dag; Meidell, Annette (Journal article; Tidsskriftartikkel; 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 ...

    • Control of rigid bodies : with applications to leader-follower spacecraft formations 

      Schlanbusch, Rune (Doctoral thesis; Doktorgradsavhandling, 2012)

    • 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)

    • Weighted Hardy Operators in Complementary Morrey Spaces 

      Lukkassen, Dag; Persson, Lars Erik; Samko, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)

    • Homogenization of a singular random one-dimensional PDE with time-varying coefficients 

      Pardoux, Etienne; Piatnitski, Andrey (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-05-04)
      In this paper we study the homogenization of a nonautonomous parabolic equation with a large random rapidly oscillating potential in the case of one-dimensional spatial variable. We show that if the potential is a statistically homogeneous rapidly oscillating function of both temporal and spatial variables, then, under proper mixing assumptions, the limit equation is deterministic, and convergence ...

    • On a New Class of Hardy-type Inequalities 

      Adeleke, EO; Cizmesija, Aleksandra; Oguntuase, JA; Persson, Lars Erik; Pokaz, D (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-11-05)
      In this paper, we generalize a Hardy-type inequality to the class of arbitrary non-negative functions bounded from below and above with a convex function multiplied with positive real constants. This enables us to obtain new generalizations of the classical integral Hardy, Hardy-Hilbert, Hardy-Littlewood-Pólya, and Pólya-Knopp inequalities as well as of Godunova’s and of some recently obtained ...

    • Weighted Hardy Operators in Complementary Morrey Spaces 

      Lukkassen, Dag; Persson, Lars-Erik; Samko, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-11-11)
      We study the weighted -boundedness of the multidimensional weighted Hardy-type operators and with radial type weight , in the generalized complementary Morrey spaces defined by an almost increasing function . We prove a theorem which provides conditions, in terms of some integral inequalities imposed on and , for such a boundedness. These conditions are sufficient in the general case, but we ...

    • Atmospheric ice monitoring system operation at Remote locations in cold region 

      Virk, Muhammad Shakeel; Rashid, Taimur; Mustafa, Mohamad Y (Journal article; Tidsskriftartikkel; 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; Tidsskriftartikkel; 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 ...