Karl Thomas Hjelmervik

Karl Thomas Hjelmervik

Førsteamanuensis
Fakultet for teknologi, naturvitenskap og maritime fag
Institutt for mikrosystemer
Campus Vestfold (G3-21)
31 00 88 14
Karl Thomas Hjelmervik was employed at the University first in 2019 in 20% position teaching physics, but transitioned to USN for full time in June 2022. His background is a MSc in Underwater acoustics at the University of Bergen in 2002 and a PhD in acoustics at NTNU in 2011. He has also worked for 20 years with defence research at FFI.

Ansvarsområder

  • Teaching physics and mathematics
  • Research within the fields of acoustics, signal processing, and oceanography

Kompetanse

  • Underwater acoustics
  • Signal processing
  • Numerical modelling
  • Oceanography
  • Teaching

CV

Utdanning

  • Cand Scient i Fysikk ved Universitetet i Bergen                                  1996 - 2002
  • PhD i akustikk og signalbehandling ved NTNU i 2011                         2004 - 2011

Yrkeserfaring

  • Gruppeleder ved Matematisk institutt på Universitetet i Bergen          1997 – 2000
  • Gruppeleder ved Høyskolen Stord/Haugesund                                   2001 – 2002
  • Forsker ved Forsvarets forskningsinstitutt i Horten                              2002 – 2022
  • Førsteamanuensis 2 ved Universitetet i Sørøst-Norge                        2019 – 2022
  • Førsteamanuensis ved Universitetet i Sørøst-Norge                           2022 -

Publikasjoner

PhD avhandling

Sonar false alarm rate suppression using classification methods based on acoustic modeling, NTNU, 2011

Journalartikler

  1. Karl Thomas Hjelmervik: Predicting sonar false alarm rate inflation using acoustic modeling and a high-resolution terrain model, IEEE Journal of Oceanic Engineering, 2010.
  2. Jan Kristian Jensen, Karl Thomas Hjelmervik & Petter Østenstad: Finding acoustically stable areas through EOF classification, IEEE Journal of Oceanic Engineering, 2012.
  3. Karl Thomas Hjelmervik, Jan Kristian Jensen og Petter Østenstad: Classification of acoustically stable areas using empirical orthogonal functions, Journal of Ocean Dynamics, 2012
  4. Karina Hjelmervik & Karl Thomas Hjelmervik: Demonstration of Comparison Methods for Ocean Model Validation, The Open Ocean Engineering Journal, 2012
  5. Karl Thomas Hjelmervik & Karina Hjelmervik: Estimating climatological temperature and salinity profiles using empirical orthogonal functions and clustering, Journal of Ocean Dynamic, 2013
  6. Karina Hjelmervik & Karl Thomas Hjelmervik: Time-calibrated estimates of oceanographic profiles using empirical orthogonal functions and clustering, Journal of Ocean Dynamic, 2014
  7. Karina Hjelmervik & Karl Thomas Hjelmervik: Detection of oceanographic fronts on variable water depths using empirical orthogonal functions, IEEE Journal of Oceanic Engineering, 2019.
  8. Karl Thomas Hjelmervik, Henrik Berg og Tale S Såstad: Predicting false alarm rates for high resolution, anti-submarine warfare sonars in a cluttering environment prone to false alarm rate inflation, IEEE Journal of Oceanic Engineering, 2019.
  9. Karl Thomas Hjelmervik og Elin M Bøhler: Optimization of active sonar parameters in a measured environment, POMA, 2021
  10. Kristoffer Engedal Andreassen og Karl Thomas Hjelmervik. "Modelled sonar and target depth distributions for active sonar operations in realistic environments." POMA, 2022.

Konferansebidrag med paper

  1. Jon Wegge, Elling Tveit, Elin Dombestein & Karl Thomas Hjelmervik: Active sonar clutter prediction, UDT, Malmø, Sverige, 2003
  2. Karl Thomas Hjelmervik: Ray tracing in the presence of an ice layer, ECUA, Delft, Nederland, 2004
  3. Karl Thomas Hjelmervik, Amund Gjersøe, Jon Wegge & Elling Tveit: Sonar False Alarm Reduction Using Detailed Bathymetry Data and Acoustic Propagation Modelling, UDT, Nederland, Amsterdam, 2005
  4. Karl Thomas Hjelmervik & Amund Gjersøe: Sonar simulation module for land-based sonar operator training, UDT, Hamburg, Tyskland, 2006
  5. Karl Thomas Hjelmervik: A quest for valid acoustic model predictions in an uncertain environment, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2007
  6. Geir Helge Sandsmark, Svein Alsterberg, Elin Dombestein, Karl Thomas Hjelmervik, Tor Knudsen, Svein Mjølsnes, Tale S Såstad, Harald Tholo & Jon Wegge: Environmental impact and assessment: In ocean evaluation of sonar system performance, expectations and experience, UDT, Napoli, Italia, 2007
  7. Karl Thomas Hjelmervik: The acoustic raytrace model Lybin - Description and applications, UDT, Glasgow, Skottland, 2008
  8. Karl Thomas Hjelmervik & Geir Helge Sandsmark: In ocean evaluation of low frequency active sonar systems, Acoustics08, Paris, Frankrike 2008
  9. Karl Thomas Hjelmervik, Elin Dombestein, Svein Mjølsnes, Tale Solberg Såstad, Jon Wegge: “The acoustic raytrace model Lybin – Description and applications”, UDT, Glasgow, 2008.
  10. Karl Thomas Hjelmervik: Target depth estimation using a ray backpropagation scheme on min-frequency, active sonar data, ECUA, Istanbul, Tyrkia, 2010
  11. Karl Thomas Hjelmervik: Inverting the water column sound speed, ECUA, Istanbul, Tyrkia, 2010
  12. Tale Solberg Såstad, Henrik Berg, Karl Thomas Hjelmervik & Wenche Oxholm: Guidelines for optimal use of active anti-submarine warfare sonars, UDT, London, England, 2011
  13. Karl Thomas Hjelmervik & Henrik Berg: Automatic target classification for low and mid-frequency anti-submarine warfare sonars, OCEANS, Bergen, Norge, 2013
  14. Karl Thomas Hjelmervik & Karina Hjelmervik: Improved estimation of oceanographic climatology using empirical orthogonal functions and clustering, OCEANS, Bergen, Norge, 2013
  15. Michael A. Ainslie, Dale D. Ellis, Jan Ehrlich, Pieter Schippers, Karl Thomas Hjelmervik & Mathieu E. G. D. Colin: Echo, reverberation and echo to reverberation ratio for isovelocity waveguides related to Weston Memorial Workshop Scenarios A2.I and A2.IV, UAC, Kreta, Hellas, 2013
  16. Karl Thomas Hjelmervik: Automatic classification for mid-frequency anti-submarine sonars – recognizing pipelines, UAC, Rhodos, Hellas, 2013
  17. Vidar Anmarkrud & Karl Thomas Hjelmervik: Modeling multistatic sonar performance, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2014
  18. Karl Thomas Hjelmervik, Henrik Berg, Dan Henrik Sekse Stender & Tale Solberg Såstad: A hybrid recorded-synthetic sonar data set for validation of ASW classification algorithms, OCEANS, Genova, Italia, 2015
  19. Karina Hjelmervik, Karl Thomas Hjelmervik & Petter Østenstad: Estimation of oceanographic profiles and climatological regions in the Barents Sea, OCEANS, Genova, Italia, 2015
  20. Karl Thomas Hjelmervik, Karina Hjelmervik & Petter Østenstad: Assessing acoustic sensitivity to oceanographic variability using climatology, UAC, Kreta, Hellas, 2015
  21. Petter Østenstad & Karl Thomas Hjelmervik: Combining climatology and ocean modelling for improved modeling of the acoustic field, UAC, Kreta, Hellas, 2015
  22. Karl Thomas Hjelmervik, Henrik Berg, Dan Henrik Sekse Stender & Tale Solberg Såstad: Optimised prediction of false alarm rate inflation for anti-submarine warfare sonars employed in littoral waters, UDT, Lillestrøm, 2016
  23. Dan Henrik Sekse Stender , Henrik Berg, Karl Thomas Hjelmervik & Tale Solberg Såstad: Assessing the performance of kinematic track features for classification of sonar targets in anti-submarine warfare, UDT, Lillestrøm, 2016
  24. Tale Solberg Såstad, Fredrik Hermansen, Karl Thomas Hjelmervik, Morten Kloster, Frode Langset, Wenche Oxholm, Dan Henrik Sekse Stender & Jørn Inge Vestgården: SIMSON – a sonar analysis tool for Underwater Warfare, UDT, Lillestrøm, 2016
  25. Henrik Berg, Karl Thomas Hjelmervik, Dan Henrik Sekse Stender & Tale Solberg Såstad: A Comparison of Different Machine Learning Algorithms for Automatic Classification of Sonar Targets. OCEANS, Monteray, 2016
  26. Tale S. Såstad, Elin Margrethe Bøhler Dombestein Fredrik Hermansen, Karl Thomas Hjelmervik, Morten Kloster, Frode Langset, Wenche Oxholm, Dan Henrik S Stender & Jørn Inge Vestgården. SIMSON - visualization and analysis of ASW sonar data. OCEANS, Monteray, 2016
  27. Andre A Søvik og Karl Thomas Hjelmervik: Comparison of measured and modelled reverberation signal-to-noise ratio in littoral waters. OCEANS, Aberdeen, 2017
  28. Dan Henrik S Stender, Henrik Berg, Karl Thomas Hjelmervik og Tale S Såstad:Assessing the performance of Signal-to-noise ratio and kinematic features in varying environments. OCEANS, Aberdeen, 2017
  29. Karl Thomas Hjelmervik, Lloyd Andreassen og Karina Hjelmervik: Detection of oceanographic fronts using empirical orthogonal functions. OCEANS, Aberdeen, 2017
  30. Henrik Berg, Tom Erik Lindhjem og Karl Thomas Hjelmervik: Rattus – a Simulation Framework for Tactical Analysis and Development, UDT, Bremen, Tyskland, 2017
  31. Petter Østenstad, Karina Hjelmervik, Karl Thomas Hjelmervik og Jon Albretsen: Adjusting modelled sound speed profiles for use in sonar operations. OCEANS, Aberdeen, 2017
  32. Jørn Inge Vestgården, Henrik Berg, Karl Thomas Hjelmervik og Dan Henrik S Stender: Sonar scattering from the sea bottom near the Norwegian coast. OCEANS, Anchorage, 2017
  33. Tale S Såstad og Karl Thomas Hjelmervik: Synthesizing realistic, high-resolution anti-submarine warfare sonar data. OCEANS, Kobe, 2018.
  34. Dan Henrik S Stender, Henrik Berg, Karl Thomas Hjelmervik og Tale S Såstad: Sensitivity to target behaviour in automatic classification on kinematic track features. OCEANS, Kobe, 2018.
  35. Henrik Berg og Karl Thomas Hjelmervik: Classification of anti-submarine warfare sonar targets using a deep neural network. OCEANS, Charleston, 2018.
  36. Karl Thomas Hjelmervik, Henrik Berg, Dan Henrik Stender, Wenche Oxholm og Tale S Såstad: Synthesizing active anti-submarine warfare sonar data. OCEANS, Marseille, 2019.
  37. Dan Henrik Stender, Karl Thomas Hjelmervik, Wenche Oxholm og Tale S Såstad: DOPPLER & SNR DEPENDENT THRESHOLDING OF CW-DATA. OCEANS, Marseille, 2019.
  38. Karl Thomas Hjelmervik, Kristoffer Engedahl Andreassen, Henrik Berg, Elin Bøhler, Dan Henrik Stender og Jørn Inge Vestgården: Bayesian occupancy grid for active sonar detection and localization of moving targets, OCEANS digital, 2020
  39. Elin M Bøhler og Karl Thomas Hjelmervik: A Monte Carlo approach for capturing the uncertainty in sonar performance modelling, OCEANS digital, 2020
  40. Henrik Berg og Karl Thomas Hjelmervik: Deep learning on active sonar data using Bayesian optimization for hyperparameter tuning, ICPR2020, 2020
  41. Wenche Oxholm, Dan Henrik S Stender, Tale S Såstad, Karl Thomas Hjelmervik, Tom Erik Lindhjem: Anti-submarine warfare - Measures of Performance, UDT, 2022
  42. Kristoffer Engedal Andreassen, Henrik Berg, Karl Thomas Hjelmervik, Tom Erik Lindhjem: Simulations of ASW operations in the littoral zone, UDT, 2022

 

Konferansebidrag uten paper

  1. Karl Thomas Hjelmervik: Ray tracing in the presence of an ice layer, Scandinavian Symposium in Physical Acoustics, Ustaoset, Norge, 2001
  2. Karl Thomas Hjelmervik: False alarm reduction in an LFAS system, Scandinavian symposium in Physical Acoustics, Ustaoset, Norge, 2005
  3. Karl Thomas Hjelmervik: Akustisk bølgeforplantning følsomhet for tidsvarierende lydhastighet, Geodesi- og hydrografidagene, Stavanger, Norge, 2006
  4. Karl Thomas Hjelmervik: Lybin, an acoustic raytrace model, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2008
  5. Karl Thomas Hjelmervik, Jan Kristian Jensen & Petter Østenstad: Finding acoustically stable areas through EOF classification, MREA, Lerici, Italia, 2010
  6. Karl Thomas Hjelmervik: Target depth estimation using a ray backpropagation scheme, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2010
  7. Karina Hjelmervik & Karl Thomas Hjelmervik: Ocean model validation methods, MREA, Lerici, Italia, 2010
  8. Karina Hjelmervik & Karl Thomas Hjelmervik: Classification of water masses using empirical orthogonal functions,  JONSMOD, Brest, Frankrike, 2012
  9. Karl Thomas Hjelmervik & Tale Solberg Såstad: Guidelines for optimal use of active anti-submarine warfare sonars, Tactical decision aids workshop, La Spezia, Italia, 2012
  10. Karina Hjelmervik & Karl Thomas Hjelmervik: Classification of water masses using empirical orthogonal functions,  IWMO, Bergen, Norge, 2013
  11. Karl Thomas Hjelmervik & Henrik Berg: Automatic classification of sonar targets using low- and mid frequency ASW sonars, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2013
  12. Karina Hjelmervik & Karl Thomas Hjelmervik: Estimating climatological profiles using empirical orthogonal functions and clustering, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2013
  13. Karl Thomas Hjelmervik & Karina Hjelmervik: Sensitivity of sonar performance to oceanographic variability, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2014
  14. Karl Thomas Hjelmervik & Henrik Berg: Automatic classification for mid-frequency sonars in a littoral environment, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2015
  15. Karl Thomas Hjelmervik, Henrik Berg, Dan Henrik S Stender og Tale S Såstad: Automatic classification of sonar targets – recent results, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2016
  16. Paul van Walree, Karl Thomas Hjelmervik og Trond Jenserud: Impact of channel fluctuations on the detection of large time-bandwidth signals, UAC, Skiathos, Hellas, 2017
  17. Tale S Såstad og Karl Thomas Hjelmervik: Synthesizing realistic, high-resolution anti-submarine warfare sonar data, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2018
  18. Karl Thomas Hjelmervik, Henrik Berg, Dan Henrik S Stender og Tale S Såstad: Automatic classification of sonar targets, Scandinavian Symposium in Physical Acoustics, Geilo, Norge, 2018
  19. Dan Henrik Stender, Karl Thomas Hjelmervik, Wenche Oxholm og Tale S Såstad: DOPPLER & SNR DEPENDENT THRESHOLDING OF CW-DATA. Scandinavian Symposium in Physical Acoustics, Geilo, 2019.
  20. Karl Thomas Hjelmervik og Tale S Såstad: Synthesizing high level data. Scandinavian Symposium in Physical Acoustics, Geilo, 2019.
  21. Karl Thomas Hjelmervik, Kristoffer Engedahl Andreassen, Henrik Berg, Elin Bøhler, Dan Henrik s Stender og Jørn Inge Vestgården: Bayesian occupancy grid for active sonar detection and localization of moving targets, SSPA 2021
  22. Karl Thomas Hjelmervik og Elin Bøhler: Optimization of active sonar parameters in a measured environment, UACE, 2021
  23. Kristoffer Engedal Andreassen og Karl Thomas Hjelmervik: Modelled sonar and target depth distributions for active sonar operations in realistic environments. UACE, 2022.

Tekniske rapporter ved FFI: 77 stk totalt