Blar i NTNU Open på forfatter "Alfredsen, Jo Arve"
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A Formation of Unmanned Vehicles for Tracking of an Acoustic Fish-Tag
Zolich, Artur Piotr; Johansen, Tor Arne; Alfredsen, Jo Arve; Kuttenkeuler, J; Erstorp, E (Chapter; Peer reviewed, 2017)In this paper we present a proof-of-concept for an hydro acoustic fish-tag position estimation and tracking system. In our field-tested concept, a formation of Unmanned Surface Vehicles (USV) creates a mobile array of ... -
A novel Doppler based speed measurement technique for individual free-ranging fish
Hassan, Waseem; Føre, Martin; Pedersen, Magnus Oshaug; Alfredsen, Jo Arve (Chapter, 2019)A novel Doppler based speed measurement technique for free-ranging acoustically tagged fish was developed and validated through a field experiment in a marine aquaculture farm. For emulated swimming speeds in the range ... -
An acoustic sensor transmitter for in situ assessment of water quality and fish behaviour during chemical treatment of a parasite-infected river system: tag design and practical use
Alfredsen, Knut; Urke, Henning Andre; Kristensen, Torstein; Kvakland, Marte; Grønningsæter, Åge; Hagen, Anders Gjørwad; Alfredsen, Jo Arve (Journal article; Peer reviewed, 2021) -
Akustisk posisjoneringssystem for fisk: PinPoint
Hammer, Joakim (Master thesis, 2008)Sammendrag Hensikten med denne masteroppgaven har vært å utvikle en autonom hydrofonbøye for PinPointsystemet. Hydrofonbøyen består av tre moduler; en kommunikasjonsmodul, en GPS-modul og en hydrofonmodul. PinPoint-systemet ... -
Assimilering av sonardata med matematiske modeller av fiskeatferd i oppdrettsmerder
Myrberg, Sondre (Master thesis, 2019)En viktig del av det å drive med oppdrett er å ha kontroll på tilstanden i merden. Ekkolodd er et hjelpemiddel for å overvåke og følge med på hva som skjer under overflaten, men hva slags informasjon gir egentlig et ekkolodd, ... -
Automated First-Feeding and Monitoring System for Marine Hatchery
Eriksen, Tor-Inge J (Master thesis, 2013)CodTech provides the Norwegian, and European aquaculture industry with facilities for testing new techniques and equipment related to the rearing of marine fish larvae. The facilities provides cutting edge technology to ... -
Automatic Inspection of Cage Integrity with Underwater Vehicle
Jakobsen, Rolf Arne Hult (Master thesis, 2011)This thesis is a preliminary study for the initiative to develop an autonomous AUV foruse in aquaculture. A micro-ROV is used to test the concept of inspecting net integrityin sh cages by analyzing video feed from a video ... -
Automatisert system for marin fiskeyngelproduksjon
Lund Jensen, Olav (Master thesis, 2008)Stor etterspørsel etter hvitfisk på verdensmarkedet har ført til økt interesse for oppdrett av marine fiskearter. For å oppnå en storskala produksjon av marin fisk kreves det også en storskala produksjon av fiskeyngel av ... -
Autonomous environmental monitoring probe for aquaculture sites
ramezaniakhmareh, alireza (Master thesis, 2012)This project aims to develop an instrument that is capable of moving vertically in a controlled manner along a taut string from the sea surface to a predetermined depth while measuring pertinent seawater parameters. The ... -
Behavioural response of farmed Atlantic salmon (Salmo salar L.) to artificial underwater lights: Wavelet analysis of acoustic telemetry data
Ulvund, John Birger; Engebretsen, S.; Alfredsen, Jo Arve; Kristensen, Torstein; Urke, H.A.; Jansen, P.A. (Peer reviewed; Journal article, 2021)Biological, environmental, economic and ethical issues become increasingly pertinent as the scale of the aquaculture industry expands. This study used acoustic telemetry data and wavelet analysis to investigate behavioural ... -
Biomonitoring using tagged sentinel fish and acoustic telemetry in commercial salmon aquaculture: A feasibility study
Føre, Martin; Frank, Kevin; Dempster, T; Alfredsen, Jo Arve; Høy, Erik (Journal article; Peer reviewed, 2017)We tested if it is technically feasible to monitor fish in real-time in full-scale commercial fish farms using acoustic telemetry. 31 Atlantic salmon were equipped with acoustic transmitter tags containing depth sensors. ... -
Bottom-detection in Doppler Velocity Logs using Recurrent Neural Networks on an embedded platform
Almås, Fredrik (Master thesis, 2022)Økt bruk av autonome undervannsfarkoster (Autonomous Underwater Vehicle, AUV) skaper en økende etterspørsel etter systemer for undervannsnavigasjon. Derfor har viktigheten av å tilby robuste og nøyaktige langsiktige systemer ... -
Characteristic current flow through a stocked conical sea-cage with permeable lice shielding skirt
Jonsdottir, Kristbjørg Edda; Pascal, Klebert; Volent, Zsolt; Alfredsen, Jo Arve (Peer reviewed; Journal article, 2021)The characteristic current flow field around a 55 m deep full-scale stocked conical Atlantic salmon sea-cage equipped with a 10 m permeable skirt was studied experimentally using acoustic Doppler velocimeters and profilers. ... -
Computer Vision-Based Robot Control For Lobster Identification and Tracking
Tesfaghiorghis, Georgis Micael (Master thesis, 2020)Europeiske hummere er høyt verdsatt og har en høy pris, men i de siste tiårene har intensiv akvakultur produksjon av hummere vist seg å være vanskelig å gjennomføre. En vanlig egenskap hos hummere er agnostisk oppførsel ... -
Control system for rotifer production
Rumí Pastor, Alejandro (Master thesis, 2007)Rotifers are used extensively as start feed for many cultured marine fish species and commercial size hatcheries require stable daily supply of high quality rotifers of substantial volumes. This is often done relying on ... -
Current flow and dissolved oxygen in a full-scale stocked fish-cage with and without lice shielding skirts
Jónsdóttir, Kristbjörg Edda; Volent, Zsolt; Alfredsen, Jo Arve (Peer reviewed; Journal article, 2020)Shielding skirts are widely used on Atlantic Salmon sea-cages as a non-invasive preventive measure against salmon lice infestations. The skirts are however known to impact the current flow and thereby the environment within ... -
Data for characterization of the optical properties of Atlantic salmon (Salmo salar) blood
Svendsen, Eirik; Randeberg, Lise Lyngsnes; Føre, Martin; Finstad, Bengt; Olsen, Rolf-Erik; Bloecher, Nina; Alfredsen, Jo Arve (Peer reviewed; Journal article, 2023)Photoplethysmography is a recent addition to physio-logging in Atlantic salmon which can be used for pulse oximetry provided that the properties for light propagation in salmon tissues are known. In this work, optical ... -
Design and development of a robotic fish tracking vehicle
Lauvås, Nikolai (Master thesis, 2020)Posisjonering av akustiske fiskemerker (tags) over tid er ønsket til bruksområder som å spore fiskers vandring gjennom fjorder. Bruken av autonome fartøy utstyrt med akustiske mottakere har i de senere årene dukket opp i ... -
Design and experimental validation of a control architecture for a wave-propelled USV: From system design to ocean studies
Dallolio, Alberto (Doctoral theses at NTNU;2022:42, Doctoral thesis, 2022)In a time of unprecedented anthropogenic pressures on the oceans, preserving the health of underwater ecosystems is of the uttermost importance. Since the beginning of human exploration of the oceans, ship-based ocean ... -
Design and Validation of a Course Control System for a Wave-Propelled Unmanned Surface Vehicle
Dallolio, Alberto; Øveraas, Henning; Alfredsen, Jo Arve; Fossen, Thor Inge; Johansen, Tor Arne (Journal article, 2022)Unlike common marine vessels, wave-propelled vehicles cannot directly control their speed, but rely instead on the forces exerted by the environment to navigate as intended. The unique navigation capabilities of such ...