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Now showing items 609-628 of 919
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Path-following in three dimensions using quaternions for a fixed-wing UAV
(Conference object; Konferansebidrag, 2017-08-08)This paper presents a three dimensional guidance strategy for fixed-wing UAVs using quaternions. The algorithm is based on constructing two quaternions, one which makes the UAV fly towards the path and one that makes the UAV follow the path. These two quaternions are then blended together such that the path-following objective is reached. The guidance algorithm is applied to a simple kinematic model ... -
PD+ based trajectory tracking of the underactuated quadrotor platform using dual quaternions
(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 ... -
Performance Analysis of Bidirectional Multi-Hop Vehicle-to-Vehicle Visible Light Communication
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-14)Vehicular visible light communication (VVLC) has emerged as a promising field of research, garnering considerable attention from scientists and researchers. VVLC offers a potential solution to enable connectivity and communication between travelling vehicles along the road by using their existing headlights (HLs) and taillights (TLs) as wireless transmitters and integrating photodetectors (PDs) ... -
Performance and Design Study of Optimized LNG Mixed Fluid Cascade Processes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-26)Mixed Fluid Cascade (MFC) processes are often claimed to be one of the most efficient methods to liquefy natural gas. Their performance depends on both operating conditions such as ambient temperature, and system design parameters such as exchanger sizes. The performance of the standard MFC process can be further improved by modifying the design with additional equipment, such as liquid refrigerant ... -
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 ... -
Permanente og mobile løsninger for tining av stikkrenner, grøfter og bekkeløp
(Master thesis; Mastergradsoppgave, 2022-05-16)Åpne linjegrøfter, stikkrenner og bekkeløp er essensielt for å ha et sikkert og velfungerende veg- og jernbanenett. Det vises at iskjøving er et av hovedproblemene som gjør at vannet fryser til is i nærheten til infrastrukturen og man får driftsforstyrrelser i form at is som enten har falt ned på vegbanen, eller fryser ut i skjæringene og gir reduksjon av profilet som jernbanens materiell krever for ... -
Perspectives and reflections on teaching linear algebra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-03)This paper presents ‘expert opinions’ on what should be taught in a first-year linear algebra course at university; the aim is to gain a generic picture and general guiding principles for such a course. Drawing on a Delphi method, 14 university professors—called ‘experts’ in this study—addressed the following questions: What should be on a first-year linear algebra undergraduate course for engineering ... -
pH-dependent endocytosis mechanisms for influenza A and SARS-coronavirus
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-10)The ongoing SARS-CoV-2 pandemic and the influenza epidemics have revived the interest in understanding how these highly contagious enveloped viruses respond to alterations in the physicochemical properties of their microenvironment. By understanding the mechanisms and conditions by which viruses exploit the pH environment of the host cell during endocytosis, we can gain a better understanding ... -
Playing a video game is more than mere procrastination
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-13)<i>Background</i>: Procrastination is seen as a severe problem among young people, and many factors have been claimed to be associated with it, playing video games being one of them. One of the reasons why video games might be related to procrastination is their ability to offer instant gratification and feedback, while at the same time offer distractions from less tempting and rewarding tasks. ... -
Pointwise estimates for heat kernels of convolution-type operators
(Journal article; Peer reviewed; Tidsskriftartikkel, 2018-04-16)We study the large‐time behaviour of the fundamental solution of parabolic equations with an elliptic part being non‐local convolution‐type operator. We assume that this operator is a generator of a Markov jump process, and that its convolution kernel decays at least exponentially at infinity. The fundamental solution shows rather different asymptotic behaviour depending on whether | x | ≲ t , or t ... -
Poly[2,2′-(4,4′-bipyridine)-5,5′-bibenzimidazole] functionalization of carbon black for improving the oxidation stability and oxygen reduction reaction of fuel cells
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-20)The rapid oxidation of carbon black (CB) is a major drawback for its use as a catalyst support in polymer electrolyte fuel cells. Here, we synthesize poly[2,20 -(4,40 -bipyridine)-5,50 -bibenzimidazole] (BiPyPBI) as a conducting polymer and use it to functionalize the surface of CB and homogenously anchor platinum metal nanoparticles (Pt-NPs) on a CB surface. The as-prepared materials were ... -
Possibility study for utilization of solar energy in Arctic areas
(Master thesis; Mastergradsoppgave, 2019-06-26)This thesis 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. An existing building block in Narvik, within the sub-arctic region, was taken as study case to analyze the potential of solar energy. -
Post-COVID ventilation design: Infection risk-based target ventilation rates and point source ventilation effectiveness
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-19)Ventilation, air filtration and disinfection have been found to be the main engineering measures to control the airborne respiratory infection transmission in shared indoor spaces. Wells-Riley model modifications allow to calculate the infection risk probability, but gaps in viral load data, risk control methods and dealing with incomplete mixing have resulted in ventilation recommendations falling ... -
Potensial for reduksjon av livssyklus klimagassutslipp ved gjenbruk og resirkulering av betong
(Master thesis; Mastergradsoppgave, 2021-05-15)Verden står ovenfor store klimaendringer og klimagassmengden fortsetter å øke. For å begrense økning av gjennomsnittstemperaturen må tiltak iverksettes for å redusere utslippene. Betong er det mest anvendte byggematerialet i verden og det brukes dobbelt så mye betong enn andre byggematerialer til sammen. Sementproduksjon antas å bidra til 7-8 prosent av klimagassutslipp på verdensbasis. Betong ... -
Potential type operators in PDEs and their applications
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017-01)We prove the boundedness of Potential operator in weighted generalized Morrey space in terms of Matuszewska-Orlicz indices of weights and apply this result to the Hemholtz equation in ℝ<sup>3</sup> with a free term in such a space. We also give a short overview of some typical situations when Potential type operators arise when solving PDEs. -
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 ... -
Pre-Holocene volcanic ash in sediments near Jan Mayen
(Conference object; Konferansebidrag, 2022-05) -
Predicting Bedside Falls using Current Context
(Peer reviewed; Chapter; Bokkapittel, 2018-02-05)Each year about a third of the elderly aged 65 or older experience a fall. Many of these falls could be avoided if fall risk assessment and prevention tools where available in the daily living situation. Such tools would need to use the current context as input to predict an imminent fall. This paper presents an approach predicting imminent falls using data from a roof-mounted infrared array combined ... -
Predicting Peak Prices in the Current Day-Ahead Market
(Chapter; Bokkapittel, 2023-06)The work presented has studied price developments in the day-ahead market. The statistical properties inherent in the time series constituting the day-to-day prices have been investigated. It is shown that these properties are radically different in 2022 than former years and resemble more chance like properties for which make predicting future peak prices especially hard. To overcome this, a space ... -
Prefabrikkert eller plassbygd? Sammenligning av byggemetode for leilighetskomplekser av tre
(Master thesis; Mastergradsoppgave, 2021-05-18)I den norske byggebransjen i dag er det lite samsvar mellom tilbud og etterspørsel av boliger, og det er dermed behov for økt effektivisering av byggebransjen. Prefabrikasjon som byggemetode har potensiale til å bidra til å øke effektiviteten i bygg- og anleggsnæringen, sett opp mot tradisjonell plassbygd metode. Denne artikkelen har dermed gjennomført en sammenligning av de positive og negative ...
