Viser treff 173-191 av 191

    • Take-Home Exams in University Mathematics and Science Subjects: Some Ethical Considerations 

      Rensaa, Ragnhild Johanne; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2024)
      This article addresses some challenging perspectives related to offering take-home exams in mathematics at university level. The challenges arose during work on a previous article where four perspectives originating from Bjerrum Nielsen’s framework (2003) were used to analyze universities’ assessment methods during the Covid lockdown in our country. The perspectives had some ethical considerations ...
    • Technical Challenges and Solutions of a three-phase bidirectional two stage Electric Vehicle charger 

      Mughal, Babur Zaman Khan (Master thesis; Mastergradsoppgave, 2022-05-15)
      The sustainability of the power grid owing to the building strain of the ever-growing demand for electrical energy urges innovative and more practical solutions that enable active participation of end-users in stable and reliable management of power systems. One of the emerging projections of such a two-way exchange of electrical power between the grid and consumers is the developing field of ...
    • Temporary Load Shedding - Optimization of power distribution system using load shedding Techniques 

      Basit, Abdul (Master thesis; Mastergradsoppgave, 2022-05-15)
      In today’s world, electrical energy is a necessity. The dependency on electricity is increasing day by day which caused the system to work under a stress state close to stability limits and disturbances. An efficient power system supplying electrical energy must be reliable, stable, secure, and reasonable to meet consumer needs. The power demand depends on several factors and weather is one of the ...
    • Tethered Quadcopter Control, Simulation and Modeling platform for a small USV 

      Wæringsaasen, Sindre (Master thesis; Mastergradsoppgave, 2021-05-18)
      Maritime Robotics main intent of the thesis is to develop understanding of a small deployable camera platform capable of providing elevated situational awareness for a small USV using a tether. The thesis goes into the state-ofthe-art methods of usage and control of a tethered drone. The thesis goes into the building and operating of the QAV250 Pixhawk 4 mini drone and making a drone simulation ...
    • Themes within lecturers' views on the teaching of linear algebra 

      Rensaa, Ragnhild Johanne; Hogstad, Ninni Marie; Monaghan, John David (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-25)
      This paper reports on themes that arose in an investigation of university lecturers’ views on the teaching of linear algebra. This focus on themes was the initial part of a study concentrating on four areas: What is important to teach in a first course in linear algebra? Are there teaching methods which are particularly suited for such a course? Are there tools that should/should not be used; and ...
    • Throughput Optimization for NOMA Energy Harvesting Cognitive Radio with Multi-UAV-Assisted Relaying under Security Constraints 

      Dang, Viet-Hung; Nguyen, Le-Mai-Duyen; Vo, Van Nhan; Tran, Hung; Ho, Tu Dac; Chakchai, So-In; Surasak, Sanguanpong (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-28)
      This paper investigates the throughput of a non-orthogonal multiple access (NOMA)-based cognitive radio (CR) system with multiple unmanned aerial vehicle (UAV)-assisted relays under system performance and security constraints. We propose a communication protocol that includes an energy harvesting (EH) phase and multiple communication phases. In the EH phase, the multiple UAV relays (URs) harvest ...
    • Thyristor based short circuit current injection in isolated grids 

      Hoff, Bjarte; Sharma, Pawan; Østrem, Trond (Peer reviewed; Bokkapittel; Chapter, 2017-02-16)
      This paper proposes a thyristor based short circuit current injector for providing short circuit current in isolated and weak grids, where sufficient fault current to trigger circuit breakers may not be available. This will allow the use of conventional miniature circuit breakers, which requires high fault current for instantaneous tripping. The method has been validated through experiments.
    • Time Series Forecasting of Reactive Power Support from Smart Converters in SDN Using Machine Learning 

      Aziz, Mujtaba (Master thesis; Mastergradsoppgave, 2023-05-19)
      The climate changes in the last few years created a major need to integrate more renewable energy sources and other low-carbon technologies into the power system network. This causes to face more changes in the power system network, which are particularly visible in distribution power networks. A higher penetration of the distributed energy resources, installed at low- voltage and or medium-voltage ...
    • TRACKING VOLUME CHANGE OF THE BULK COMMODITIES WITH INTERFEROMETRIC SAR 

      Wu, Zhenming; Ellingsen, Pål Gunnar; Jia, Haiying; Ådland, Roar Os (Journal article; Tidsskriftartikkel; Peer reviewed, 2023)
      Bulk commodities are crucial to global economy and modern society. Some commodities, such as grain, are normally stored in cylindrical tanks. The height of the tank’s roof may be correlated to the substance quantity inside the tank, indicating that roof displacement may be associated with the volume of the bulk commodities. Here we analyzed the displacements derived from C-band Sentinel-1 data ...
    • Transient analysis of road tunnel power system 

      Ivanova, Elizaveta (Master thesis; Mastergradsoppgave, 2018-08-16)
      The main tasks of Statens Vegvesen is to plan, build and maintain the roads of Norway. Tunnels are included as a part of this task. Due to expected changes in usage patterns and needs, the Norwegian authorities decided to adapt to the European model the design of low voltage networks. The backup power system is one of the most important parts of the installation and presents an independent source ...
    • A Two-Stage Deep Modeling Approach to Articulatory Inversion 

      Sabzi Shahrebabaki, Abdolreza; Olfati, Negar; Imran, Ali Shariq; Johnsen, Magne Hallstein; Siniscalchi, Sabato Marco; Svendsen, Torbjørn Karl (Chapter; Bokkapittel, 2021-05-13)
      This paper proposes a two-stage deep feed-forward neural network (DNN) to tackle the acoustic-to-articulatory inversion (AAI) problem. DNNs are a viable solution for the AAI task, but the temporal continuity of the estimated articulatory values has not been exploited properly when a DNN is employed. In this work, we propose to address the lack of any temporal constraints while enforcing a ...
    • Ubemannede flaksende mikrofly 

      Oland, Espen (Journal article; Tidsskriftartikkel, 2013)
    • Under Seawater Capacitive Power Transfer for Maritime Charging Applications 

      Al-Sallami, Hussein Mahdi Yaseen; Hattori, Reiji; Hoff, Bjarte; Østrem, Trond (Chapter; Bokkapittel, 2023-09-12)
      Underwater capacitive power transfer (CPT) can provide an inexpensive and light electric charging solution with good misalignment tolerance for unmanned maritime vehicles. This paper investigates the effect of the changing of the frequency and the distance on the power transfer and overall efficiency of the underwater CPT system, considering the dielectric losses of the medium. It also proposes and ...
    • Underactuated Control of Quadrotors with Collision Avoidance 

      Oland, Espen; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Peer reviewed; Tidsskriftartikkel, 2013)
      In this paper a saturated controller is derived that solves the translational control problem for underactuated quadrotors. The controller is applied to multiple quadrotors during a formation reconfiguration where the quadrotors move from an initial position to a desired position. The null-space-based behavioral control method is a popular method for avoiding collisions between mobile agents, and ...
    • Underactuated Waypoint Tracking of a Fixed-Wing UAV 

      Oland, Espen; Schlanbusch, Rune; Kristiansen, Raymond (Journal article; Peer reviewed; Tidsskriftartikkel, 2013)
      In this paper a new method of performing waypoint tracking is shown for underactuated fixed-wing UAVs. The position error can be mapped onto the desired axis using a desired rotation matrix, while the velocity error can be mapped to the desired axis using a desired angular velocity. With all errors defined along one axis, the tracking problem is easily solved using only one thruster. A velocity ...
    • Underwater Inductive Power Transfer with Wireless Charging Applications 

      Monari, Lydiah Mitchelle (Master thesis; Mastergradsoppgave, 2022-05-16)
      Underwater wireless power transfer (UWPT) has become an area of great interest due to the advancement of autonomous underwater vehicles (AUVs) and electic boats. This paper seeks to investigate the variation of the coupling coefficient and power transfer in air versus in seawater. The design is based on a class E converter as it can achieve soft-switching inherently. I made the transmitter and ...
    • Wireless Charging for Small Electric Vessels 

      Omosanya, Hafeez Abolade (Master thesis; Mastergradsoppgave, 2019-06-28)
      With the presence of traditional thick and heavy cables for charging, the risk of humans exposed to high-voltage, and due to mechanical wear and tear in conductive materials, inductive wireless charging was introduced which is the future of charging technology. This project has focused on magnetic-coupled wireless transfer with some key components involved such as a DC voltage source, a full-bridge ...
    • Wireless charging of offshore wind service vessels 

      Nilsen, Henrik Fjeld (Master thesis; Mastergradsoppgave, 2021-05-18)
      This report discusses the possibility for wireless charging solutions for electric vessels, with a focus on offshore wind turbine service. Where the charging time is minimal and safety for crew is important. Different types of wireless technologies have been studied, where the Inductive power transfer (IPT) is shown to be the preferred technology. Inductive power transfer (IPT) grants a safe ...
    • Zonal Day-Ahead Energy Market: A Modified Version of the IEEE 39-bus Test System 

      Tricarico, Gioacchino; Wagle, Raju; Dicorato, Maria; Forte, Giuseppe; Gonzalez-Longatt, Francisco; Torres, José Luis Rueda (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-11)
      The increasing penetration of renewable energy resources (RES) in transmission system operating conditions require a suitable test system and a dataset to cope with current issues. RES penetration remarkably affects day-ahead market outcomes regarding zonal prices and dispatched generation levels. For this purpose, zonal day-ahead energy market models in the presence of RES in the generation mix ...