IEEE OES Japan Chapter organized the Distinguished Lecture (DL) program in June 2018 after the OCEANS’18 MTS/IEEE
Kobe / Techno-Ocean 2018 as fellows.
Ocean Acoustic Signal Processing: A Bayesian Approach by Dr. James V. Candy
Reported by Hayato Kondo, OES Japan Chapter, TC Member
On the 4th of June, 2018, a Distinguished Lecturer, Dr. James V. Candy, gave a lecture titled “Ocean Acoustic Signal Processing: A Bayesian Approach” at the Etchujima Campus of the Tokyo University of Marine Science and Technology (TUMSAT). This DL program was planned as a post event of the OCEANS’18 MTS/IEEE Kobe/Techno-Ocean 2018. Eleven participants from university, research institution and company enjoyed his thought-provoking lecture.
According to Jim, “The application of Bayesian methods to complex ocean acoustic processing problems, especially in shallow water, has evolved from well-known probability distributions like Gaussian leading to model-based, Kalman filtering solutions to nonparametric representations driven by the uncertain ocean environment leading to sequential Monte Carlo or equivalently particle filtering solutions. In this lecture, an overview of particle filtering methods coupled to a shallow ocean modal tracking application motivated by the nonlinear nature of underlying ocean acoustic phenomenology is presented. Beginning with a brief overview of Bayesian inference leading to sequential processors, the Bayesian paradigm is established. Simulation-based methods using sampling theory and sequential Monte Carlo realizations are discussed. Here the usual limitations of nonlinear approximations and non-gaussian processes prevalent in classical algorithms (e.g. Kalman filters) are no longer a restriction to perform Bayesian processing. It is shown how the underlying state variables are easily assimilated into this sequential Bayesian construct. With this in mind, the idea of a particle filter, which is a discrete nonparametric representation of a probability distribution, is developed and shown how it can be implemented using sequential methods. Finally, an oceanic application of this approach is discussed comparing the performance of the particle filter designs with that of the classical unscented Kalman filter.”
The lecture was comprehensive and high-leveled, it was well-arranged for beginners of Bayesian methods to easily understand from basics to applications by giving not only theories but also real data obtained at sea tests.
After the lecture, participants were invited to take a short-tour of the university campus. There is a Meiji-maru, a national important cultural property. She was an iron ship planned to be used as a lighthouse patrol ship, ordered by the Meiji Government from a British shipbuilder, Napier, located in Glasgow and built in 1874. The ship was a state-of-the-art ship equipped with special rooms and saloons and, in addition to patrolling lighthouses, it also served as a royal ship. (www.kaiyodai.ac.jp/english/overview/facilities/meijimaru.html)
Acoustics in Fisheries Research: Evolving Technology and
New Opportunities to Solve Old Problems by Dr. Kenneth G. Foote
Reported by Katsunori Mizuno, OES Japan Chapter,
Beacon Associate Editor
Dr. Kenneth G. Foote, who is a Senior Scientist, Applied Ocean Physics & Engineering, Woods Hole Oceanographic Institution, was invited as a distinguished lecturer and talked about the acoustic technologies in fisheries research. The title of the lecture was “Acoustics in fisheries research: evolving technology and new opportunities to solve old problems.” A total of 21 participants, including academian, business people, and students, attended his lecture. Most of the audience are concerned with the fisheries acoustic through their research and business, therefore, the lecture was filled with the excitement and seemed to be meaningful.
The lecture was started from the introduction about Dr. Foote’s achievements by Dr. Koichi Sawada, who was a group leader, National Research Institute of Fisheries Engineering, FRA. Dr. Sawada said “The greatest effort of Ken-san is a finding of the “linearity” between the backscatter strength and the abundance of fish school.” The author was really impressed because the finding was one of the most important ideas in fisheries acoustic. Dr. Sawada continued, “However, the specialty of Ken-san is “non-linear” acoustics.” It was really interesting because the expert of non-linear acoustics found the most important linear dependence!
Dr. Foote introduced broad topics of technologies in sonar and applications in fisheries research. The basic sonar performances, e.g., bandwidth, sensitivity, dynamic range, and beamforming, are still important, and consistently improved by novel powerful signal processors and platforms for the sonar. He also said the steady development may solve the general problems in fisheries research that involve detection, localization, classification, and quantification. The recent case studies related to the problems were briefly explained with the introduction of several types of sonars. These practical talks strongly attracted the participants. After the lecture, the author recalled the famous word “ (onkochishin),” which means “developing new ideas based on study of the past learning from the past”.