Now showing items 581-600 of 926

    • Construction professionals’ perspectives on drivers and barriers of sustainable construction 

      Tokbolat, Serik; Karaca, Ferhat; Durdyev, Serdar; Calay, Rajnish K (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-05)
      With the associated environmental challenges and unsustainable patterns of construction, there is also notable awareness and willingness among the state bodies to adopt sustainability measures and practices in Kazakhstan. This study explores the drivers of and barriers inhibiting the adoption of sustainability paradigm in the construction context of Kazakhstan. The drivers and barriers were validated ...
    • Dual quaternion control: a review of recent results within motion control 

      Johansen, Tor-Aleksander; Sánchez, José J.; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-24)
      This paper presents a review of recent results in the field of dual quaternion based motion control. In addition, we derive two control laws for trajectory tracking control of a fully actuated rigid-body based on the resemblance of dual quaternion kinematics and dynamics to the quaternion based rotational kinematics and dynamics. A velocity error sliding surface and an integrator backstepping ...
    • Equivalent integral conditions related to bilinear Hardy-type inequalities 

      Kanjilal, Saikat; Persson, Lars Erik; Shambilova, Guldarya E (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      Infinitely many, even scales of, equivalent conditions are derived to characterize the bilinear Hardy-type inequality under various ranges of parameters.
    • Singularly perturbed spectral problems in a thin cylinder with fourier conditions on its bases 

      Piatnitski, Andrey; Rybalko, Volodymyr (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      The paper deals with the bottom of the spectrum of a singularly perturbed second order elliptic operator defined in a thin cylinder and having locally periodic coefficients in the longitudinal direction. We impose a homogeneous Neumann boundary condition on the lateral surface of the cylinder and a generic homogeneous Fourier condition at its bases. We then show that the asymptotic behavior of the ...
    • Homogenization of Levy-type operators with oscillating coefficients 

      Kassmann, Moritz; Piatnitski, Andrey; Zhizhina, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-05)
      The paper deals with homogenization of Lévy-type operators with rapidly oscillating coefficients. We consider cases of periodic and random statistically homogeneous micro-structures and show that in the limit we obtain a Lévy-operator. In the periodic case we study both symmetric and non-symmetric kernels whereas in the random case we only investigate symmetric kernels. We also address a nonlinear ...
    • Homogenization of biased convolution type operators 

      Piatnitski, Andrey; Zhizhina, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-07)
      This paper deals with homogenization of parabolic problems for integral convolution type operators with a non-symmetric jump kernel in a periodic elliptic medium. It is shown that the homogenization result holds in moving coordinates. We determine the corresponding effective velocity and prove that the limit operator is a second order parabolic operator with constant coefficients. We also consider ...
    • Exploring future C++ features within a geometric modeling context 

      Bratlie, Jostein; Dalmo, Rune (Conference object; Konferansebidrag, 2019-11)
      The development of the C++ programming language and its standard library has undergone a renaissance since the introduction of the C++11 standard, making the language more relevant than ever, through modern features, simplification and expansion of the standard library. Comparing past and future feature sets (C++17, C++20, ...) similar to comparing different programming languages. In this article ...
    • Limit behaviour of diffusion in high-contrast periodic media and related Markov semigroups 

      Piatnitski, Andrey; Pirogov, S; Zhizhina, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      The goal of the paper is to describe the large time behaviour of a symmetric diffusion in a high-contrast periodic environment and to characterize the limit process under the diffusive scaling. We consider separately the C0 and the L2 settings.
    • Numerical study on the ventilation performance of a livestock house built in porous panels in Cold Regions 

      Mustafa, Mohamad; Xu, Yizhong; Calay, Rajnish K; Sørensen, Bjørn Reidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11)
      This paper presents a numerical prediction on the assessment of natural ventilation on a livestock house built in porous panels, aided by Computational Fluid Dynamics techniques. A typical climatic environment in Cold Regions was taken into consideration. The ventilation performances have been assessed by the distribution of indoor air velocity, turbulence intensity and local mean age of air through ...
    • Numerical study on the ventilation performance of a livestock house built in porous panels in Cold Regions 

      Xu, Yizhong; Mustafa, Mohamad; Calay, Rajnish K; Sørensen, Bjørn Reidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      This paper presents a numerical prediction on the assessment of natural ventilation on a livestock house built in porous panels, aided by Computational Fluid Dynamics techniques. A typical climatic environment in Cold Regions was taken into consideration. The ventilation performances have been assessed by the distribution of indoor air velocity, turbulence intensity and local mean age of air through ...
    • Architecture for Safe Human-Robot Collaboration: Multi-Modal Communication in Virtual Reality for Efficient Task Execution 

      Shu, Beibei; Sziebig, Gabor; Pieters, Roel (Peer reviewed; Chapter; Bokkapittel, 2019-08-01)
      Task-sharing and Human-Robot Collaboration has gained increased attention with the widespread commissioning and usage of collaborative robots. However, recent studies show that the fenceless collaborative robots are not as harmless as they look like. In order to study Human-Robot Interaction scenarios, in a safe manner, we propose to execute the scenario in Virtual Reality simulation and afterwards ...
    • Preliminary Results on Waypoint Tracking for Spacecraft with Actuator Constraints 

      Oland, Espen; Andersen, Tom Stian (Peer reviewed; Chapter; Bokkapittel, 2019-07-22)
      This paper presents preliminary results on how to perform waypoint tracking with spacecraft with actuator constraints. It considers a simplified spacecraft model and can be considered a deep space model, and shows how to perform waypoint tracking with only one main thruster together with full attitude control. As the spacecraft reaches close to the waypoint during a deceleration phase that makes the ...
    • Controlling a Chain of Integrators with Constrained Actuation Using Exponential Activation Functions 

      Oland, Espen; Kristiansen, Raymond (Peer reviewed; Chapter; Bokkapittel, 2019-10-24)
      This paper shows how to control a chain of integrators with constrained actuation by using exponential activation functions. Specifically, it shows how the control law can be decomposed into several parts that can be activated as they are required, resulting in a simple control law that is able to make the states converge fast to zero.
    • Review of energy demands and wind resource assessment of the Solovetsky Archipelago 

      Ghani, Rizwan; Virk, Muhammad Shakeel; Kangash, Aleksei; Maryandshev, Pavel; lubov, viktar; Mustafa, Mohamad (Journal article; Tidsskriftartikkel, 2019-07)
      This paper aims to analyse the current situation of the energy system of the remote island territory of Solovetsky Archipelago. The Solovetsky historical and cultural complex was included in the list of UNESCO World Heritage Sites. Diesel fuel, which is used on the archipelago is expensive and pollutes the environment. By using Computational Fluid Dynamics (CFD) based numerical method, this study ...
    • 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 ...
    • Feasibility study for utilization of solar energy in the arctic areas 

      Tamrakar, Stutee; Mustafa, Mohamad; Riise, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      This research investigates a solar thermal system and a solar photovoltaic system which produces local energy, by incoming solar radiation, to meet the energy consumption demand of a residential building in the arctic region. The study on the use of the solar systems in the arctic areas is rare and often doubted. So, to analyze the potential of solar energy, a study case of an existing building block ...
    • Embeddings of weighted generalized Morrey Spaces into Lebesgue Spaces on fractal sets 

      Samko, Natasha Gabatsuyevna (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-19)
      We study embeddings of weighted local and consequently global generalized Morrey spaces defined on a quasi-metric measure set (X, d, μ) of general nature which may be unbounded, into Lebesgue spaces Ls(X), 1 ≤ s ≤ p < ∞. The main motivation for obtaining such an embedding is to have an embedding of non-separable Morrey space into a separable space. In the general setting of quasi-metric measure ...
    • PD+ based trajectory tracking of the underactuated quadrotor platform using dual quaternions 

      Johansen, Tor-Aleksander; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-29)
      We address the problem of state feedback trajectory tracking of the underactuated quadrotor platform in the dual quaternion framework through a PD+ tracking controller. The control law negates the need of generating a desired attitude trajectory as the translational error is mapped directly onto the rotational actuators through a virtual frame. More precisely, we show uniform practical asymptotic ...
    • Blending functions based on trigonometric and polynomial approximations of the Fabius function 

      Olofsen, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      Most simple blending functions are polynomials, while more advanced blending functions are, for example, rational or expo-rational fractions. The Fabius function has the required properties of a blending function, but is a nowhere analytic function and cannot be calculated exactly everywhere on the required domain. We present a new set of trigonometric and polynomial blending functions with the shape ...
    • Finite element method application of ERBS triangles 

      Kravetc, Tatiana (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11)
      In this paper we solve an eigenvalue problem on a circular membrane with fixed outer boundary by using a finite element method, where an element is represented as an expo-rational blending triangle. ERBS triangles combine properties of B-spline finite elements and standard polynomial triangular elements. The overlapping of local triangles allows us to provide a flexible handling of the surface while ...