We very much appreciated the oppositions and discussions with the external comittee members Professor Kathleen Wage, George Mason University, and Senior Researcher Carl-Inge Colombo Nilsen, Norwegian Computing center:
The full thesis text will soon be publicly available through the "DUO" publishing portal at the University of Oslo: Link to DUO
Main research findings of the thesis
In the current thesis, I provide novel approaches to estimate the performance bounds for both adaptive and conventional beamformers. Beamforming combines the signal of multiple transducers to form a narrow beam pointing towards the target. Such an array can consist of antenna elements as used in mobile communication, or ultrasonic sensors as used in sonars. Adaptive beamformers have, in general, a better potential to suppress unwanted signals then conventional beamformers, but they also tend to be more sensitive to calibration errors. My results contribute to a better understanding of beamforming performance. I foresee these results to be applicable in the development of novel and efficient beamformers for specific applications, such as bathymetric sonar, medical ultrasound, imaging radar and mobile communication. The current thesis provides both novel theoretical results derived from first principles, and open-source tools for evaluating beamformers. The results provide a balanced emphasis on the accuracy and robustness of beamformers, which encourages engineers to pay equal consideration to these aspects when choosing the appropriate beamformer for an application.
Trial lecture
Gabór also gave the trial lecture “Deep Learning for Direction of Arrival Estimation”.