Viser treff 41-60 av 118

    • Evaluations of UAV-enabled FSO Communications in the Arctic 

      Pottoo, Sahil Nazir; Ellingsen, Pål Gunnar; Ho, Tu Dac (Journal article; Tidsskriftartikkel, 2022-02-16)
      This paper investigates the feasibility of using free space optics (FSO) for communication between multiple hovering unmanned aerial vehicles (UAVs) and a detection unit (DU) in the Arctic. The uniqueness that sets apart UAV-based FSO systems from conventional FSO systems is the dynamics of the system since location and inclination of the UAV changes over time due to wind load and UAV oscillations. ...
    • Real-time Volt-Var control of grid forming converters in DER-enriched distribution network 

      Wagle, Raju; Sharma, Pawan; Charu, Sharma; Amin, Mohammad; Gonzalez-Longatt, Francisco (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-06)
      The growing installation of distributed energy resources (DERs) in a distribution network (DN) poses substantial issues related to voltage regulation. Due to constrained switching operation and slower response time, traditional voltage regulation devices cannot handle current voltage-related challenges. One alternative to solve these problems is to use smart converters to control the reactive ...
    • A Review of Power Converters for Ships Electrification 

      Al-Sallami, Hussein Mahdi Yaseen; Hoff, Bjarte; Østrem, Trond (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-07)
      Fully electric ships have become popular to meet the demand for emission-free transportation and improve ships' functionality, reliability, and efficiency. Previous studies reviewed the shipboard power systems, the different types of shipboard energy storage devices, and the influences of the shore-to-ship connection on ports' electrical grid. However, the converter topologies used in the electrification ...
    • 6G Network Architecture Using FSO-PDM/PV-OCDMA System with Weather Performance Analysis 

      Singh, Mehtab; Pottoo, Sahil Nazir; Armghan, Ammar; Aliqab, Khaled; Alsharari, Meshari; Abd El-Mottaleb, Somia A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-04)
      This paper presents a novel 160 Gbps free space optics (FSO) communication system for 6G applications. Polarization division multiplexing (PDM) is integrated with an optical code division multiple access (OCDMA) technique to form a PDM-OCDMA hybrid. There are two polarization states: one is X-polarization generated from adjusting the azimuthal angle of a light source at 0° while the other is ...
    • Mode division multiplexing free space optics system with 3D hybrid modulation under dust and fog 

      Pottoo, Sahil Nazir (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-13)
      Mode division multiplexing (MDM) is an emerging information transmission technique in which multiple data signals can be transmitted simultaneously on different modes of a single wavelength laser beam over a free-space channel. MDM is a potential technique for the realization of high-speed spectral efficient communication links for future generations of wireless networks. We present a novel MDM-based ...
    • Gender perspectives on a flipped classroom environment 

      Rensaa, Ragnhild Johanne; Fredriksen, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-20)
      The present paper investigates the gender perspective of flipped classroom. In particular, it considers how the collaborative setting of in-class group-work affect the female population of students. The paper draws on an in-depth analysis of the interview with one such student. The focus of this interview was on interactional collaboration between peers during group work activities in a ...
    • A Field Programmable and Dynamic Configurable Power Electronic Converter Concept 

      Hoff, Bjarte (Chapter; Bokkapittel, 2022)
      This paper proposes the concept of a field programmable and configurable power electronic converter together with a new synthesis method. By considering the converter as a pack of resources, the converter topology and configuration of inputs and outputs can be programmed in the field through, utilising the available device resources.
    • Cascade-Based Controlled Attitude Synchronization and Tracking of Spacecraft in Leader-Follower Formation 

      Schlanbusch, Rune; Loria, Antonio; Nicklasson, Per Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-05-05)
      We propose controllers for leader-follower attitude synchronization of spacecraft formations in the presence of disturbances, that is, the leader spacecraft is controlled to follow a given reference, while a follower spacecraft is controlled to synchronize its motion with the leader’s. In the ideal disturbance-free scenario, we show that synchronization takes place asymptotically. Moreover, we ...
    • Conformal Transformation Analysis of Capacitive Wireless Charging 

      Al-Sallami, Hussein Mahdi Yaseen; Hoff, Bjarte; Ellingsen, Pål Gunnar; Østrem, Trond (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-30)
      This paper studies the capacitive coupling in a capacitive power transfer (CPT) system designed for charging applications. It proposes mathematical models using the conformal transformation for calculating air-gapped and underwater capacitance and verifies the proposed models using COMSOL multiphysics and measurements. The measured results show that we can achieve nano-farad capacitance ranges ...
    • Roach Infestation Optimization MPPT Algorithm for Solar Photovoltaic System 

      Calay, Rajnish K; Pradhan, Chittaranjan; Senapati, Manoj Kumar; Ntiakoh, Nicholas Kakra (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-16)
      Solar photovoltaic (PV) power has several advantages such as free availability, absence of rotating parts, can be easily integrated with building architecture, and need little maintenance. However, the PV cell current–voltage (I–V) characteristics are non-linear and power generated from a PV array depends on solar insolation/irradiation and panel temperature. The extracted PV output power is ...
    • Norwegian freshmen engineering students' self-efficacy, motivation, and view of mathematics in light of task performance 

      Rensaa, Ragnhild Johanne; Tossavainen, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-15)
      We report on 71 Norwegian freshmen engineering students' self-efficacy and motivation in mathematics. Students' responses to five-point Likert scales were analysed across three groups corresponding to different performance levels on a set of mathematical tasks. The groups were investigated to trace differences in self-efficacy, motivation, and the epistemological beliefs about the nature of mathematics. ...
    • Control of Spacecraft Formation with Disturbance Rejection and Exponential Gains 

      Schlanbusch, Rune; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      We address the problem of state feedback translational motion control of a spacecraft formation through a modified sliding surface controller using variable gains and I^2 action for disturbance rejection. The exponential varying gains ensure faster convergence of the state trajectories during attitude maneuver while keeping the gains small (and the system less stiff) for station keeping. Integral ...
    • Ingeniørstudenters bruk av læringsverktøy i et lineær algebraemne : hvilken rolle spiller nettbaserte forelesninger? 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-11)
      I denne artikkelen diskuteres studentenes bruk av læringsverktøy med spesielt fokus på et nettbasert tilbud. Egne forelesninger i et emne i lineær algebra for master ingeniørstudenter, fjerde år, har blitt streamet og publisert, og jeg har undersøkt hvordan studentene har brukt disse forelesningene. Data er innsamlet første og tredje gang dette ble gjort, og hovedvekten i denne artikkelen er lagt ...
    • A note about frequencies being close or amplitudes being small in frequency analysis 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-10)
      In an earlier paper, an alternative method for how to solve the frequency analysis problem was offered. The object of the present paper is to bring about how to handle situations where the frequencies are close to each other or there is an amplitude that is really small.
    • En tematisk analyse av hva ingeniørstudenter gjør når de lærer lineær algebra 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-15)
      Denne artikkelen diskuterer hva ingeniørstudenter gjør når de lærer lineær algebra. Arbeidet inngår i et pågående forskningsprosjekt om læring, og grunnlagsdataene for artikkelen ble samlet inn ved at studentene besvarte et obligatorisk spørreskjema der spørsmålet om hva de gjør når de lærer lineær algebra, ble stilt som et åpent spørsmål. Dataene representerer derfor studentenes egne ord om hva de ...
    • A computational intelligence-based maximum power point tracking for photovoltaic power generation system with small‐signal analysis 

      Senapati, Manoj Kumar; Pradhan, Chittaranjan; Calay, Rajnish Kaur (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-01)
      There are multiple peak functions in its output power characteristic curve of a photovoltaic (PV) array under partial shading conditions (PSCs), the perturb and observe (P&O) may fail to track the global maximum power point (GMPP). Therefore, a reliable maximum power point tracking (MPPT) technique is essential to track the GMPP within an appropriate time. This article proposes a hybrid technique ...
    • Bio‐inspired hybrid BFOA‐PSO algorithm‐based reactive power controller in a standalone wind‐diesel power system 

      Wagle, Raju; Sharma, Pawan; Charu, Sharma; Gjengedal, Terje; PRADHAN, CHITTARANJAN (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-05)
      With an increase in the penetration of renewable energy sources such as wind into the power systems, the operation and control of voltage/reactive power have become more complicated and challenging than ever. As a result, the reactive power imbalance between reactive power generation and demand instigates a reduction in system voltage stability. To deal with the aforesaid scenarios, automatic voltage ...
    • 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 ...
    • 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 ...
    • Keeping track of samples in multidisciplinary fieldwork 

      Ellingsen, Pål Gunnar; Ferrighi, Lara; Godøy, Øystein Arne; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-10)
      We here present methods, tools and results for efficiently collecting metadata and tracking samples collected in the field. The samples and metadata were collected during scientific cruises conducted by amongst others marine biologists, oceanographers, geochemists and marine geologists in the Nansen Legacy project. It is here reported on the successful development and implementation of a system ...