Now showing items 119-138 of 191

    • Observations of sunlit N2+ aurora at high altitudes during the RENU2 flight 

      Ellingsen, Pål Gunnar; Lorentzen, Dag Arne; Kenward, David; Hecht, James H.; Evans, J. Scott; Sigernes, Fred; Lessard, Marc (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-24)
      We present measurements of sunlit aurora during the launch of the Rocket Experiment for Neutral Upwelling 2 (RENU2) on the 13 December 2015, 07:34 UTC. The in situ auroral conditions coincide with those of sunlit aurora and were characterised by the 391.4 and 427.8 nm N<sub>2</sub> <sup>+</sup> emissions. A correlation between several auroral wavelengths, as measured by a meridian-scanning ...
    • Optical water types of the Nordic Seas and adjacent areas 

      Aas, Eyvind; Højerslev, Niels Kristian; Høkedal, Jo; Sørensen, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-05-20)
      A new map of Jerlov's optical water types in the Nordic Seas and adjacent waters at 139 locations, as well as a table with statistical and geographical properties of the vertical attenuation coefficient of downward irradiance at 475 nm, are presented. The data analysis is based on 715 recordings at different stations, at latitudes between 54° and 82°N, and longitudes between 31°W and 49°E, obtained ...
    • Optimal bruk av reaktive ressurser 

      Arnesen, Jan Tore (Master thesis; Mastergradsoppgave, 2021-05-18)
      God kontroll av reaktiv effekt er en helt nødvendig del av et velfungerende kraftsystem. Reaktiv effekt er funksjon av spenning og lastvinkel, men er i størst grad påvirket av spenningen under normale forhold. Det finnes mange forskjellige reaktive ressurser i kraftsystemet, og de har forskjellige egenskaper og karakteristikker. Statiske reaktive ressurser er kondensatorbatterier, reaktorer og ...
    • Optimal power flow based coordinated reactive and active power control to mitigate voltage violations in smart inverter enriched distribution network 

      Wagle, Raju; Sharma, Pawan; Charu, Sharma; Amin, Mohammad (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-30)
      Voltage violations are the main problem faced in distribution networks (DN) with a higher penetration of inverter-based generations (IBG). Active and reactive power control from smart inverters (SI) can mitigate such violations. Optimal power flow (OPF)-based control provides more accurate operating set points for the coordinated operation of SIs. Therefore, this paper presents a three-phase OPF-based ...
    • Optimal routing and charging procedures for electric buses 

      Masliakova, Kseniia (Master thesis; Mastergradsoppgave, 2016-04-06)
      The goal of the project is to use Ant Colony Optimization techniques with Genetic Algorithm to design and analyse routes and recharging schedules for electric buses. One system so-called “en route” charging was analysed where the bus applies a kind of pantograph at bus stops to recharge the bus batteries. This implies more frequent, but short recharging intervals. The program offers diff t variants ...
    • Optimal Solutions for Underwater Capacitive Power Transfer 

      Al-Sallami, Hussein; Hoff, Bjarte; Østrem, Trond (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-09)
      Capacitive power transfer (CPT) has attracted attention for on-road electric vehicles, autonomous underwater vehicles, and electric ships charging applications. High power transfer capability and high efficiency are the main requirements of a CPT system. This paper proposes three possible solutions to achieve maximum efficiency, maximum power, or conjugate-matching. Each solution expresses the ...
    • Optimal Volt Var control in Smart Distribution Networks 

      Shamraiz, Shamraiz (Master thesis; Mastergradsoppgave, 2021-05-24)
      Both the generation and transmission power networks are facing new threats and opportunities as the number of distributed energy resources (DERs) grows. Because of the high solar PV penetration, voltage rise and voltage volatility are becoming major problems in the distribution network. Voltage regulating devices (VRDs), such as on load tap changers (OLTCs), phase voltage regulators (SVRs), and ...
    • Optimization of industrial power grid of Narvik 

      Khan, Md Nafis Ul Hoq (Master thesis; Mastergradsoppgave, 2023-05-22)
      The objective of this study is to review a comprehensive plan for optimization framework for the industrial power grid. Few factors considered such as power generation, transmission, distribution, energy storage solutions, cost development. The aim targets an overview of planning and optimization for a hydrogen production plant in Narvik region. It will improve the overall efficiency, stability, ...
    • Optimization of the mass of a sandwich plate that TAM is producing 

      Jensen, Bjarne Steinulv (Master thesis; Mastergradsoppgave, 2017-06-15)
      In this report the possibility to optimize the mass of a sandwich plate that TAM produces have been reviewed. Dimensions of the plate is 2602mm x 2404mm with a core thickness of 40mm, top facing of 3mm and bottom facing of 1mm. To simplify the computations they calculate with uniform facings of 1mm. The function of the sandwich plate is to lift livestock with wires that are fastened in the four ...
    • Parabolic reflector for focusing of underwater acoustic waves 

      Rasmussen, Helene Liebak; Flø, Julianne Tjervåg (Master thesis; Mastergradsoppgave, 2017-06-15)
      Kongsberg Maritime has produced a transponder placed on the seabed designed for receiving and transmitting sound waves from vessels and ROVs. The soundwaves contain data regarding depth and location, and can be transformed to energy thus increasing the transponder battery lifetime. The transponder can only receive a small amount of energy, since its receiving area is small. This project aims to ...
    • Path planning and reactive based control for a quadrotor with a suspended load 

      Corona Sanchez, Jose Juan; Kristiansen, Raymond; Andersen, Tom Stian (Conference object; Konferansebidrag, 2021-06)
      This paper presents a solution to quadrotor cargo transportation, more precisely when cargo is suspended as a sling load. The challenge lies in payload position control and swing attenuation, which we approach by dividing the model into subsystems: attitude quadrotor in free flight, and translational and attitude load dynamics. We propose a solution based on reactive control, in the sense that we ...
    • Path planning for UAV harvesting information from dynamical wireless sensor nodes at sea 

      Ho, Tu Dac; Grøtli, Esten Ingar; Johansen, Tor Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-16)
      A system of several wireless sensor nodes and one unmanned aerial vehicle (UAV) is considered in this research. The nodes are only floating and drifting with the sea stream. The UAV will be operating as a data mule to gather sensing information from wireless sensor nodes. Unlike prior studies, this paper addressed a realistic ocean model for the nodes movements which will be the references to the ...
    • Path-following in three dimensions using quaternions for a fixed-wing UAV 

      Andersen, Tom Stian; Kristiansen, Raymond (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 

      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 ...
    • Performance Analysis of Bidirectional Multi-Hop Vehicle-to-Vehicle Visible Light Communication 

      Refas, Souad; Acheli, Dalila; Yahia, Selma; Meraihi, Yassine; Ramdane-Cherif, Amar; Van, Nhan Vo; Ho, Tu Dac (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) ...
    • Perspectives and reflections on teaching linear algebra 

      Rensaa, Ragnhild Johanne; Hogstad, Ninni Marie; Monaghan, John David (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 ...
    • 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 ...
    • Prestasjonsoppfølging av elektriske brytere via datahøsting og analyse av plattformdata 

      Solrød, Andreas (Master thesis; Mastergradsoppgave, 2023-05-21)
      This thesis is a study of data material extracted from log files belonging to the oil and gas installation Norne. The data is put into a system, analyzed, and assessed how it can be used to drive performance monitoring of electrical switches. The thesis presents theory related to the task about ignition source, tag, maintenance and time determinations, the systems SAS and SMS on which the logs are ...
    • A proxy for reliable 5G (and beyond) mmWave communications. Contributions to multi-path scheduling for a reliability focused mmWave proxy 

      Tofah, Dzifa Korbla Wisdom (Master thesis; Mastergradsoppgave, 2022-05-16)
      Reliable, consistent and very high data rate mobile communication will become especially important for future services such as, among other things, future emergency communication needs. MmWave technology provides the needed capacity, however, lacks the reliability due to the abrupt capacity changes any one path experiences. Intelligently making use of varying numbers of available mmWave paths, ...
    • PSO and Kalman Filter-Based Node Motion Prediction for Data Collection from Ocean Wireless Sensors Network with UAV 

      Ho, Tu Dac; Grøtli, Esten Ingar; Johansen, Tor Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-13)
      In this paper, we consider a wireless sensor network of nodes at the sea surface drifting due to wind and sea currents. In our scenario an Unmanned Aerial Vehicle (UAV) will be used to gather data from the sensor nodes. The goal is to find a flyable path which is optimal in terms of sensor node energy consumption, total channel throughput between the UAV and sensor nodes, flight time for the UAV and ...