Blar i NTNU Open på forfatter "Alfredsen, Jo Arve"

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    • Design and validation of a system of autonomous fish tracking vehicles 

      Lauvås, Nikolai; Urke, Henning Andrè; Alfredsen, Jo Arve (Chapter, 2022)
      Abstract: This paper presents the technical design and validation of an autonomous surface vehicle (ASV) system capable of robotic search, localization and autonomous tracking of free-ranging fish carrying acoustic transmitter ...

    • Design of a low power acoustic Telemetry Buoy 

      Moen, Stian Orø (Master thesis, 2009)
      A telemetry buoy is a standalone device used to receive acoustic pulse-position modulated signals from digital tags attached to fish. The buoy is submerged in the sea and will store any valid signals from tagged fish. The ...

    • Designing a Flow-Through Particle Imaging System for Autonomous Surface Vehicles 

      Haugum, Matias (Master thesis, 2022)
      Innsamling av vannprøver er ofte gjort for h˚and, og logistikken rundt innhenting og analyse av prøver kan være en tidkrevende prosess. In-situ partikkelavbilding ved hjelp av autonome overflatefartøy og billedtakingsystemer ...

    • Designing an embedded closed loop motor control system 

      Riple, Laurits Telle (Master thesis, 2018)
      A Polargraph drawing machine is a machine that positions the drawing gondola by using a couple of cords. By doing that and controlling the drawing action it s possible to print an image much larger than conventional ...

    • Development of DP System for Merlin WR200 ROV 

      Knausgård, Lasse Muri (Master thesis, 2013)
      This thesis presents and documents the efforts to model, develop and implement a full six-degree-of-freedom dynamic positioning system for IKM Subsea's Merlin WR200 ROV. It also documents the performance of the system ...

    • Digital Twins in intensive aquaculture — Challenges, opportunities and future prospects 

      Føre, Martin; Alver, Morten Omholt; Alfredsen, Jo Arve; Rasheed, Adil; Hukkelås, Thor; Bjelland, Hans Vanhauwaert; Su, Biao; Ohrem, Sveinung Johan; Kelasidi, Eleni; Norton, Tomas; Papandroulakis, Nikos (Peer reviewed; Journal article, 2024)
      Digital Twin technology has emerged to become a key enabling technology in the ongoing transition into Industry 4.0. A Digital Twin is in essence a digital representation of an asset that provides better insight into its ...

    • Dynamic Positioning for ROV Operating in Fish Farms 

      Drozdik, Ron (Master thesis, 2015)
      The usages of Remotely Operated Unmanned Underwater Vehicles (ROVs') for inspection of marine structures is today an essential part of the offshore industry. However, in the case of inspection of fish farms, the ROV has ...

    • Dynamics of dissolved oxygen inside salmon sea-cages with lice shielding skirts at two hydrographically different sites 

      Jónsdóttir, Kristbjörg Edda; Volent, Zsolt; Alfredsen, Jo Arve (Peer reviewed; Journal article, 2020)
      Shielding skirts are widely used as a non-invasive preventive measure against salmon lice Lepeophtheirus salmonis infestations on Atlantic salmon Salmo Salar L. in sea-cages. Low levels of dissolved oxygen (DO) are reported ...

    • ECG augmented pulse oximetry in Atlantic salmon (Salmo salar)—A pilot study 

      Svendsen, Eirik; Føre, Martin; Randeberg, Lise Lyngsnes; Olsen, Rolf-Erik; Finstad, Bengt; Remen, Mette; Bloecher, Nina; Alfredsen, Jo Arve (Peer reviewed; Journal article, 2023)
      Understanding the tolerance limits of fish is crucial for developing aquaculture operations that ensure good animal welfare. However, there exist little data describing the physiological responses in farmed Atlantic salmon, ...

    • Effect of cage size on oxygen levels in Atlantic salmon sea cages: A model study 

      Alver, Morten; Føre, Martin; Alfredsen, Jo Arve (Peer reviewed; Journal article, 2022)
      The supply of dissolved oxygen (DO) to salmon in sea cages depends on many interacting factors including biomass density, temperature and current speed. With other factors being equal, hypoxic conditions are more likely ...

    • Embedded System for Underwater Data Acquisition 

      Halsos, Odd Inge (Master thesis, 2020)
      En små-skala oppdrftsaktuator, designet for a holde en gitt dybde mellom 0 og 50 meter, har potensial til å bli et nyttig verktøy med bruksområde relatert til kart- legging av undervannsstrømmer og innsamling av data. Ut ...

    • Feed Distribution in Large Scale Sea Cage Aquaculture: Experiments, modelling and simulation 

      Skøien, Kristoffer Rist (Doctoral theses at NTNU;2017:14, Doctoral thesis, 2017)
      The objective of this thesis was to gain new insight into the process of feeding in large scale sea cage aquaculture and investigate novel methods of feeding in order to increase profitability, welfare and minimize ...

    • Feed intake in Atlantic salmon fed with or without surface spreading of feed 

      Aas, Turid Synnøve; Ytrestøyl, Trine; Åsgård, Torbjørn Einar; Skøien, Kristoffer Rist; Alver, Morten Omholt; Alfredsen, Jo Arve (Journal article, 2020)
      In intensive salmon farming, it is common practice to spread the feed over a large surface area, assuming that spreading of the feed increases feed intake in the fish. However, the impact on the feed pellets during spreading ...

    • Feed intake in Atlantic salmon fed with two different spreading patterns of feed 

      Aas, Turid Synnøve; Ytrestøyl, Trine; Åsgård, Torbjørn Einar; Skøien, Kristoffer Rist; Alver, Morten Omholt; Alfredsen, Jo Arve (Report;14, Research report, 2015)
      Atlantic salmon with initial body weight 0.6 kg kept in 3.3 m3 tanks was fed one meal daily, either by dropping the feed from one point, or by spreading the feed over the water surface, for one month. The relative feed ...

    • Feed spreaders in sea cage aquaculture – Motion characterization and measurement of spatial pellet distribution using an unmanned aerial vehicle 

      Skøien, Kristoffer Rist; Alver, Morten; Zolich, Artur Piotr; Alfredsen, Jo Arve (Journal article; Peer reviewed, 2016)
      Pneumatic rotary feed spreaders represent essential equipment in the feeding system of present day industrial-scale sea cage aquaculture. This study presents experimentally obtained attitude measurements and corresponding ...

    • Fish on net: Acoustic Doppler telemetry and remote monitoring of individual fish in aquaculture 

      Hassan, Waseem (Doctoral theses at NTNU;2021:259, Doctoral thesis, 2021)
      The two main contributions of this thesis are the Internet of Fish (IoF) concept and a novel fish swimming speed measurement principle. The IoF concept is a reliable communication protocol which could relay acoustic telemetry ...

    • Fish welfare based classification method of ocean current speeds at aquaculture sites 

      Jónsdóttir, Kristbjörg Edda; Hvas, Malthe; Alfredsen, Jo Arve; Føre, Martin; Alver, Morten; Bjelland, Hans Vanhauwaert; Oppedal, Frode (Journal article; Peer reviewed, 2019)
      ABSTRACT: A major trend in marine aquaculture is to move production to more exposed sites with occasionally rough ocean current events. However, it is unclear whether fish will thrive in these extreme environments, since ...

    • Heart rate and swimming activity as indicators of post-surgical recovery time of Atlantic salmon (Salmo salar) 

      Føre, Martin; Svendsen, Eirik; Økland, Finn; Gräns, Albin; Alfredsen, Jo Arve; Finstad, Bengt; Hedger, Richard David; Uglem, Ingebrigt (Peer reviewed; Journal article, 2021)
      Background Fish telemetry using electronic transmitter or data storage tags has become a common method for studying free-swimming fish both in the wild and in aquaculture. However, fish used in telemetry studies must be ...

    • Heart rate and swimming activity as stress indicators for Atlantic salmon (Salmo salar) 

      Svendsen, Eirik; Føre, Martin; Økland, Finn; Gräns, Albin; Hedger, Richard David; Alfredsen, Jo Arve; Uglem, Ingebrigt; Rosten, Carolyn; Frank, Kevin; Erikson, Ulf Gøran; Finstad, Bengt (Peer reviewed; Journal article, 2020)
      We investigated the relationship between telemetry measurements of heart rate and swimming activity and the physiological status in farmed Atlantic salmon (Salmo salar) to assess the potential to use telemetry measurements ...

    • Implantable sensing technologies for monitoring of behavioural and physiological dynamics in farmed Atlantic salmon 

      Svendsen, Eirik (Doctoral theses at NTNU;2023:339, Doctoral thesis, 2023)
      Atlantic salmon aquaculture is a major food industry with 1.5 million tonnes produced for worldwide consumption in 2022. However, in Norway during the same year, current farming methods resulted in a 17.1% mortality rate ...