Scientific Work

Thomas Lagö’s background before entering the university, is from industry, and as the first “25-4″ (a person 25 years of age and at least four years of experience), he joined the university using a separate 25-4 allocation group. College credits in all key topics were still mandatory, and Lagö collected these via Hermods (a correspondence institute). Lagö then entered Lund Institute of and with his industry perspective, had an immediate impact on teachers and departments, already at regular course level. Thus, he was quickly selected as a teacher for different courses and lab exercises, long before he finished his Master’s Degree. His man interest was signal processing and telecommunication theory, but also measurement techniques and applied electronics were of interest. Lagö worked in a part time capacity at the department for Measurement Technologies as a Ph.D. student, but then moved to the department of Telecommunication Theory, still keeping a good contact with professor Hertz at the previous department and for some time helping out with selected courses in measurement technology.

Electrical Engineering is the foundation for Thomas  Lagö’s background, but it turns out that many applications in acoustics, sound and vibration uses advanced signal processing tools, and the mathematical platform is very similar. Thus, it was possible for Thomas Lagö to enter these vibro-acoustic applications and perform very well, and actually contribute with new ideas and concepts. Several of these ideas have led to patents, industrial implementations and numerous publications.

The interest for acoustic applications began early, and already at graduate level, he participated in a research project founded by STU (a governmental organization). When Thomas  Lagö later joined Hewlett-Packard, he involved Lund University (Dr. Per Eriksson1 and the company Signal Control AB) in many collaborative research projects. These projects led to patents and other innovations, of major interest for Volvo and other large Swedish companies. With time, more and more international projects were initiated by Dr. Thomas Lagö, often as joint projects with Lund University and companies like Signal Control AB.

The research work performed by Dr. Thomas Lagö has been applied, and focused on vibro-acoustic applications using signal processing and control theory as the mathematical and more scientific foundation. The main work can divided into the following categories:

Hydro-acoustics 

The development of a new estimation method for Doppler Current Estimation, named The Symmiktos Method®. This work was expanded by analyzing the foundation for the classical Gaussian-based approach using the covariance  method. It turns out, that the classical assumption that relies on the Gaussian assumption, is rarely fulfilled. Thus, a new backscattering signal model has been proposed based upon the evaluation using many water locations with different current properties, many signal processing tools and many depths. This extensive work was summarized in the eleven volume technical report (!), with about 600 pages per volume. Based on the experience and outcome of this analysis, a new non-linear filtering method was proposed and used for the analysis of current data. This innovative work was summarized in Lagö’s doctoral thesis.’ Numerous papers were presented at international conferences. The project also led to a complete industrial installation at the Hongkong Marine Department, analyzing the current at different depths (profiling current measurements). The system is still in operation and is used to guide the traffic scheduling in the Ma-Wan channel, that is highly dependent on the water current at different depths (often extreme currents).

Active Noise and Vibration Control

Thomas Lagö started the active noise and vibration control research group at the Blekinge University, and also founded the company Active Control AB. In this work, that was initiated by the participation the European Community research project ASANCA (Advanced Studies on Active Noise Control in Aircraft), Lagö developed a research group that expanded greatly during his period, at the Blekinge University. Some of the projects were (Lagö was the manager for all of them):

  • ASANCA-II, a large European Community research project (Advanced Studies on Active Noise Control in Aircraft).
  • Pipe noise attenuation using stacked piezo-actuators. This project was performed in collaboration with the shipyard in Karlskrona (Karlskronavarvet)
  • Hearing conversation program utilizing active damping in ear muffs, speech enhancement using spectral subtraction like algorithms and virtual sound to decrease hearing loss for Super Puma pilots at the air force.
  • AVIIS, Active Vibration Isolation In Ships.
  • CG13, active acoustic suppression in ships using loudspeakers.
  • Active Vibration Isolation in High-Speed Trains.
  • Active Vibration Suppression in Cutting Applications Using Embedded Actuators and Sensors.
  • Gamla Ullevi: Below, some text in regards to this project can be found.
  • Granö — a water poweer station with vibration challenges.

Contributions to Industrial Signal Processing

With the extensive industrial and university experience, it has become natural for Thomas Lagö to connect the different groups in collaborative research. This mutually beneficial work has led to numerous projects and papers presented at international conferences and multiple patents. Visit the separate page for more information.

Medical Applications

Sound Engineering