Institutt for datateknologi og beregningsorienterte ingeniørfag: Nye registreringer
Viser treff 181-200 av 234
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Periodic homogenization of nonlocal operators with a convolution-type kernel
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017)The paper deals with a homogenization problem for a nonlocal linear operator with a kernel of convolution type in a medium with a periodic structure. We consider the natural diffusive scaling of this operator and study the limit behavior of the rescaled operators as the scaling parameter tends to 0. More precisely we show that in the topology of resolvent convergence the family of rescaled operators ... -
Homogenization of biomechanical models for plant tissues
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017)In this paper homogenization of a mathematical model for plant tissue biomechanics is presented. The microscopic model constitutes a strongly coupled system of reaction-diffusion-convection equations for chemical processes in plant cells, the equations of poroelasticity for elastic deformations of plant cell walls and middle lamella, and Stokes equations for fluid flow inside the cells. The chemical ... -
Stationary convection-diffusion equation in an infinite cylinder
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-21)We study the existence and uniqueness of a solution to a linear stationary convection–diffusion equation stated in an infinite cylinder, Neumann boundary condition being imposed on the boundary. We assume that the cylinder is a junction of two semi-infinite cylinders with two different periodic regimes. Depending on the direction of the effective convection in the two semi-infinite cylinders, we ... -
Pre-evaluation and interactive editing of B-spline and GERBS curves and surfaces
(Conference object; Konferansebidrag, 2017-12)Interactive computer based geometry editing is very useful for designers and artists. Our goal has been to develop useful tools for geometry editing in a way that increases the ability for creative design. When we interactively editing geometry, we want to see the change happening gradually and smoothly on the screen. Pre-evaluation is a tool for increasing the speed of the graphics when doing ... -
Two-scale convergence in thin domains with locally periodic rapidly oscillating boundary
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)The aim of this paper is to adapt the notion of two-scale convergence in Lp to the case of a measure converging to a singular one. We present a specific case when a thin cylinder with locally periodic rapidly oscillating boundary shrinks to a segment, and the corresponding measure charging the cylinder converges to a one-dimensional Lebegues measure of an interval. Themethod is then applied to the ... -
A new look at classical inequalities involving Banach lattice norms
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017-12-08)Some classical inequalities are known also in a more general form of Banach lattice norms and/or in continuous forms (i.e., for ‘continuous’ many functions are involved instead of finite many as in the classical situation). The main aim of this paper is to initiate a more consequent study of classical inequalities in this more general frame. We already here contribute by discussing some results of ... -
Matrix factorization of multivariate Bernstein polynomials
(Journal article; Peer reviewed; Tidsskriftartikkel, 2015)Ordinary univariate Bernstein polynomials can be represented in matrix form using factor matrices. In this paper we present the definition and basic properties of such factor matrices extended from the univariate case to the general case of arbitrary number of variables by using barycentric coordinates in the hyper-simplices of respective dimension. The main results in the paper are related to the ... -
Multi-source data collection for state-of-the-art data analysis from ground-proximate images in sea ice classification
(Konferansebidrag; Conference object, 2017-08-08)In modern data analysis it is imperative to use well maintained data sources with curated content. This publication gives an approach for research areas, where there is no such central facility. The specific area used here is sea ice classification from images. The publication is split into two parts. The first part describes the integration of discontinuous sources for different aspects of data ... -
Additive weighted Lp estimates of some classes of integral operators involving generalized Oinarov kernels
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017) -
Regression analysis using a blending type spline construction
(Peer reviewed; Chapter; Bokkapittel, 2017-10-18)Regression analysis allows us to track the dynamics of change in measured data and to investigate their properties. A sufficiently good model allows us to predict the behavior of dependent variables with higher accuracy, and to propose a more precise data generation hypothesis. By using polynomial approximation for big data sets with complex dependencies we get piecewise smooth functions. One way ... -
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 ... -
Modelling and simulating a hybrid electric vehicle
(Master thesis; Mastergradsoppgave, 2017-06-12)This thesis presents an overview of the different types of hybrid electric vehicle structures and basic guidelines regarding choice of components. The simulation model of a hybrid electric vehicle was created for this thesis to investigate the impact on fuel efficiency in relation to rolling resistance coefficient and vehicle weight. Although the model is not designed for optimal engine operation, ... -
Transition to DC distribution grids
(Master thesis; Mastergradsoppgave, 2017-08-15)"The war between AC and DC has emerged once again due to the rapid development and advancement of electric power technologies. Nowadays, power electronics and DC/DC converters are able to change voltage levels, which could only be achieved by an AC transformer hundred years ago. Rising trend development of electric vehicle and renewable energy technology have led to an urgency for re-evaluation of ... -
Intelligent load frequency control in an isolated wind-solar PV-micro turbine-diesel based micro-grid using V2G integration
(Master thesis; Mastergradsoppgave, 2017-06-12)Abstract Modern power systems need more intelligence and flexibility to maintain and control a generation load balance from subsequent serious disturbances due to the emerging of more renewable energy sources. This problem is becoming more significant today because of the increasing number of micro-grids (MGs). MGs usually use renewable energies in electrical production those fluctuate naturally. ... -
DC distribution systems
(Master thesis; Mastergradsoppgave, 2017-06-12)In today’s distribution system, the dominating type of current used is AC. In newer time, improvements have been done within the field of DC. The developments that are achieved, are in terms of converter efficiency and conversion capabilities. Along with development of DC equipment, the use and development of renewable energy sources have increased. This has brought up the topic of using DC in the ... -
Design of a grid connected photovoltaic power electronic converter
(Master thesis; Mastergradsoppgave, 2017-06-12)In this thesis, the designing of a grid-connected photovoltaic system for the power electronic laboratory of UiT- Campus Narvik has been carried out. The relevant topics and literature regarding the elements in a photovoltaic system and grid connection standards have been studied and reviewed. A system with the capacity and ratings of solar modules currently available has been designed in Simulink. ... -
Electric vehicles and vehicle-to-grid technology. How utilities can play a role
(Master thesis; Mastergradsoppgave, 2017-06-12)Adverse effects of fossil fuel burning internal combustion engine vehicles has alarmed nations worldwide. With recent technological advancements in electric vehicle industry, governments throughout the world are promoting wider adoption of electric vehicles to mitigate environmental issues. However, increasing popularity of electric vehicles will pose a great threat to existing electric grids due ... -
FPGA-based data acquisition system for GNSS receiver for LEO-satellites applications
(Master thesis; Mastergradsoppgave, 2017-06-12)The modern Low Earth Orbit satellites (LEO-satellites) technology is highly complex and reliable than it was yesterday. Nowadays, the LEO-satellites applications extend from civilian to military applications. However, LEO-satellites require a Global Navigation Satellite System (GNSS) service, to achieve various tasks which require positioning and localizing. The challenge is to have a GNSS receiver ... -
FPGA-based tracking system for GNSS receivers
(Master thesis; Mastergradsoppgave, 2017-06-12)This report presents the design and simulation of code and carrier tracking system for a GNSS receiver. The GNSS receiver processes the signal sent by satellites in space. These signal contain carrier wave signal, ranging code and navigation data in encrypted form. To demodulate the navigation data, the processing block should accurately track the phase of incoming code and the frequency of incoming ... -
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 ...