Now showing items 1-10 of 276
Two-sided estimates of the Lebesgue constants with respect to Vilenkin systems and applications
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017-03-13)
In this paper, we derive two-sided estimates of the Lebesgue constants for bounded Vilenkin systems, we also present some applications of importance, e.g., we obtain a characterization for the boundedness of a subsequence of partial sums with respect to Vilenkin–Fourier series of H 1 martingales in terms of n's variation. The conditions given in this paper are in a sense necessary and sufficient.
Scenario-based approaches for handling uncertainty in MPC for power system frequency control
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017)
A stochastic nonlinear model predictive controller (SNMPC) is designed for automatic generator control of a proxy of the Nordic power system, and it is compared with a multi-stage nonlinear model predictive controller (MNMPC). Both controllers are scenario based, but originate in two different disturbance modeling paradigms; stochastic and deterministic. A simulation study indicates that the two ...
A case study to estimate thermal conductivity of ABS in Cold Climate Chamber
(Journal article; Peer reviewed; Tidsskriftartikkel, 2015-10-22)
Non steady state thermal conductivity of ABS was estimated using an analytical approach in a Cold Climate Chamber at ?10?C and ?14?C. Two hollow cylinders of ABS of varying thickness were used to estimate the conductivity. The material was porous but the porosity was unknown. This paper is a case study to understand, if it is reasonable to estimate the thermal conductivity using the analytical varying ...
Lagrangian and ALE Formulations For Soil Structure Coupling with Explosive Detonation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
Simulation of Soil-Structure Interaction becomes more and more the focus of computational engineering in civil and mechanical engineering, where FEM (Finite element Methods) for soil and structural mechanics and Finite Volume for CFD (Computational Fluid Dynamics) are dominant. New advanced formulations have been developed for FSI (Fluid Structure Interaction) applications using ALE (Arbitrary ...
Recognizing Bedside Events Using Thermal and Ultrasonic Readings
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-09)
Falls in homes of the elderly, in residential care facilities and in hospitals commonly occur in close proximity to the bed. Most approaches for recognizing falls use cameras, which challenge privacy, or sensor devices attached to the bed or the body to recognize bedside events and bedside falls. We use data collected from a ceiling mounted 80 60 thermal array combined with an ultrasonic sensor ...
To Measure Relative Permittivity of Atmospheric Ice Using Frequency Sweep
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-31)
The use of AD59333 IC for detecting atmospheric ice and atmospheric ice type was evaluated in this article. A prototype circuit was developed and was tested using a frequency sweep from 40 Hz to 20 kHz. The IC was calibrated using 100 kΩ resistor. The real and imaginary components of discrete Fourier transform were recorded at each frequency increment in order calculate the gain factor at each ...
A field study of atmospheric icing analysis in a complex terrain of the high north
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-12)
Analyses of atmospheric icing events hold the key for computing the significant parameters leading to icing load calculations. In the cold regions of the high north, atmospheric icing loads on structures become important when it comes to design and safety of infrastructures. Furthermore, icing load calculations over a certain period of time provide a vital input for designers to improve the ...
Atmospheric ice accretion on non rotating vertical circular cyliner
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-22)
Study of atmospheric ice accretion on a non-rotating vertical circular cylindrical object was carried out at dry and wet ice conditions. Both numerical and experimental techniques were used during this study. 3D numerical study was carried out using computational fluid dynamics based approach, whereas experimental study was carried out at Cryospheric Environmental Simulator ‘CES’ in Shinjo, Japan. ...
Experimental study of relative permittivity of atmospheric ice
(Journal article; Peer reviewed; Tidsskriftartikkel, 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 ...
Numerical Study of Atmospheric Icing on Non Rotating Circular Cylinders in Tandem Arrangement
(Journal article; Tidsskriftartikkel; 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 ...