Recent additions

  • 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 ...
  • CFD modelling of pollutant transport from a docked marine vessel: Multiphysics 2019 [poster] 

    Madsen, Synne; Asier, Zubiaga; Khawaja, Hassan; Boiger, Gernot (Conference object; Konferansebidrag, 2019)
    With the increase of the human activities in the Arctic, including land and sea, is resulting in higher release of pollutants to the environment. These pollutants can be categorised as gases released in the air such as carbon dioxide, sulphur dioxide, NOx, etc., and waste released in seas such as chemical toxins, microplastic, etc. This work presents a computational fluid dynamics (CFD) study ...
  • Qualitative visualization of the development of stresses through infrared thermography 

    Stange, Even; Andleeb, Zahra; Khawaja, Hassan (Journal article; Peer reviewed, 2019)
    In this work, the IR thermography was used to study the steel specimens (DIN 50125 Standard) undergoing the tensile tests. The tensile tests were performed using GUNT® Hamburg Universal Material Tester. The tensile specimens were clamped, and the test force was applied using a hand-operated hydraulic system. A dial gauge measured the elongation of the specimens. Using the WP 300.20 system for data ...
  • Non-parametric Linear Technique for Measuring the Efficiency of Winter Road Maintenance in the Arctic Area 

    Hatamzad, Mahshid; Polanco Pinerez, Geanette (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-05)
    Improving the performance of Winter Road Maintenance (WRM) can increase the traffic safety and reduce the cost as well as environmental impacts. This study evaluates the efficiency of WRM technique, named salting, in the Arctic area by using Data Envelopment Analysis (DEA), which is a non-parametric linear method to measure the efficiencies of decision-making units (DMUs) based on handling multiple ...
  • Multidimensional Hardy-type inequalities on time scales with variable exponents 

    Fabelurin, Olanrewaju O; Oguntuase, J. A.; Persson, Lars Erik (Journal article; Peer reviewed, 2019)
    A new Jensen inequality for multivariate superquadratic functions is derived and proved. The derived Jensen inequality is then employed to obtain the general Hardy-type integral inequality for superquadratic and subquadratic functions of several variables.
  • Ventilation and environmental control of underground spaces: A short review 

    Li, Angui; Kosonen, Risto; Melikov, Arsen; Yang, Bin; Olofsson, Thomas; Sørensen, Bjørn Reidar; Zhang, Linhua; Cui, Ping; Han, Ou (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-13)
    More and more underground spaces were used in 21st century because of rapid urbanization, traffic problems, etc. Underground city, metro, tunnel, mine, industrial and agriculture engineering, civil air defence engineering need large underground spaces. Underground spaces with different thermal, ventilation and lighting environments may cause comfort, health and safety problems. Concrete problems ...
  • Optimization of the CO2 Liquefaction Process-Performance Study with Varying Ambient Temperature 

    Jackson, Steven; Brodal, Eivind (Journal article; Peer reviewed, 2019-10-22)
    In carbon capture utilization and storage (CCUS) projects, the transportation of CO2 by ship can be an attractive alternative to transportation using a pipeline, particularly when the distance between the source and usage or storage location is large. However, a challenge associated with this approach is that the energy consumption of the liquefaction process can be significant, which makes the ...
  • Multiphysics study of infrared thermography (IRT) applications 

    Andleeb, Zahra; Ilyas, Muhammad; Khawaja, Hassan; Moatamedi, Mojtaba (Conference object; Konferansebidrag, 2019-12)
    Infrared thermography is the science of detecting infrared energy emitted from an object, converting it to apparent temperature, and producing images of that radiation, called thermograms. Infrared thermography means "beyond red temperature image". IR thermography being a remote non-contact/non-destructive means of testing is perfectly suitable for tests in extreme environments. Also, it is fast, ...
  • Best Venue to Disseminate Multiphysics Research 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2019-12)
    Multiphysics analysis has been developed over the recent past to better represent the behaviour of complex processes by the use of simultaneous modelling of a number of systems. This development is driven by the industrial need to further the understanding of real physical phenomena in order to develop and design safer and more efficient products which are environmentally friendly. Such analyses ...
  • The International Conference of MULTIPHYSICS 2020 

    Khawaja, Hassan (Conference object; Konferansebidrag, 2019-12)
    Multiphysics analysis has become increasingly important in recent years due to demand in design and understanding of complex systems. The objective of the conferences is to share and explore findings on mathematical advances, numerical modelling and experimental validation of theoretical and practical systems in a wide range of applications.

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