The University of Oslo is closed. The PhD defence and trial lecture will therefore be fully digital and streamed directly using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation.
Ex auditorio questions: the chair of the defence will invite the audience to ask ex auditorio questions either written or oral. This can be requested by clicking 'Participants -> Raise hand'.
Trial lecture
Title: "Acoustics for mapping marine habitats - state-of-the art and research trends"
Main research findings
Multi-beam echo sounder (MBES) is an advanced sonar system for mapping the seabed by the mean of acoustic waves. This thesis explores through realistic sonar simulation, new signal processing designs and solutions that may be advantageous for the next generations of MBES systems.
Orthogonal waveforms where multiple signals can share the same frequency band with minimum interferences have been investigated. We demonstrate the feasibility of an encoded multi-sector MBES system with orthogonal waveforms. Results show that the new system can be a viable alternative for seabed mapping as it maintains a correct accuracy while the bandwidth and the range resolution per sector have been significantly increased. The work provides analytical performance model that includes the characteristics of a sonar system and the geometry of the target and enable a quick assessment of the signal quality before a given task. The last topic of this work was the development of algorithms for correcting the Doppler shift that affects matched filters with linear frequency modulation. We have proposed innovative solutions that may extend the usable time for data acquisition in adverse conditions without compromising the signal quality.
Adjudication committee:
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Professor Mirjam Snellen, Acoustics group, Delft University of Technology, The Netherlands
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Associate Professor Egil Eide, Department of Electronic Systems, Norwegian University of Science and Technology (NTNU), Norway
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Professor Svein-Erik Hamran, Department of Technology Systems, University of Oslo, Norway
Supervisors
- Professor II Roy Edgar Hansen, Department of Informatics, University of Oslo, Norway
- Professor Andreas Austeng, Department of Informatics, University of Oslo, Norway
- Associate Professor Alan Joseph Hunter, University of Bath, Department of Mechanical Engineering/Department of Informatics, University of Oslo, Norway
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Frank Tichy, Kongsberg Maritime AS
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Fabrice Prieur, Department of Informatics, University of Oslo, Norway
Chair of defence
- Professor Carsten Griwods, Department of Informatics, UiO
Contact information to Department: Anniken R. Birkelund