The comprehensive research activity around the World in the fields of Underwater Acoustics and Signal Processing being strongly supported by new experimental technique and equipment and by the parallel fast developments in computer technology and solid state devices, which has led to a rapidly reducing cost of digital processing thus enabling more complex processing to be carried out economically, emphasize how necessary it is at intervals of a few years through a NATO Advanced Study Institute (NATO ASI) and guided by leading experts to study the conquests in the fields of Underwater Acoustics and Signal Processing. This need of study is moreover stressed by the interdisciplina­ rity of Underwater Acoustics and Signal Processing, where a strong impact from other branches of science, - Geophysics, Radioastronomy, Bioengineering, Telecommunication, Seismology, Space Research etc. - is taking place, which makes it an extre­ mely difficult task for scientists to follow-up the development in all its phases and to preserve the general view of its rapid­ ly increasing number of possibilities. The present Proceedings of the NATO ASI held in Copenhagen during August 1980 join the series of proceedings of NATO summer schools on Underwater Acoustics and Signal Processing held during the past 20 years. The equality and the fusion of the individual research fields of Underwater Acoustics and Signal Processing and the separate introduction of advanced research results from other scientific areas related to underwater acoustics such as transducers characterize the subject matter of this NATO ASI.

Inhalt

I: Underwater Sound Sources and Propagation.- Noise Sources, Radiation and Mitigation.- Inhomogeneities and Instabilities in Underwater Sound Propagation.- Medium Inhomogeneities and Instabilities: Effects on Spatial and Temporal Processing.- Chemical Sound Absorption in the Sea.- Environmental Tresholds of Ambient Noise in the Ocean.- Underwater Explosives: Scaling of Source Spectra.- The Remote Sensing of Factors Influencing Underwater Acoustics.- Scattering from Inhomogeneities.- Deterministic Propagation Modelling I: Fundamental Principles.- Deterministic Propagation Modelling II: Numerical Results.- Stochastic Propagation Modelling.- A Brief History of Submarine Exploration of the Arctic Basin and Contiguous Marginal Sea Ice Zones.- A Calculation of Complex Wavenumbers of Virtual Modes in a Pekeris Model.- Ambient Noise Generation in Pack Ice.- Acoustic Detection, Communication, and Signal Processing Requirements for the Optional Deployment of SSBNs in the Poseidon-X Mode in Shallow Ocean Waters.- Propagation of Sound in Marine Sediments.- Signal Processing Aspects on Nonlinear Acoustics.- Calculation of the Accurate Difference Frequency Field of a Parametric Circular Piston.- II: Transducer Technology.- Modern Transducers, Theory and Practice.- New Types of Transducers.- Status of Ultrasonic Lens Development.- Control of Radiated Pressure Using State Variable Feedback.- III: Mathematical Fundamentals of Signal Processing.- A Review of Adaptive Antennas.- Adaptive Beamforming with Emphasis on Narrowband Implementation.- Random Acoustic Arrays.- Array Adaptive Noise Cancellation under Signal Leakage Conditions.- Multi Dimensional Constrained Lattice Processor for Adaptive Arrays.- General Detection and Estimation Theory in an Adaptive Context.- Detection and Estimation. A Summary of Results.- Fast Algorithms for Time Domain Adaptive Array Processing.- Time Delay Estimation in a Sensor Array.- Modeling, Algorithmic and Performance Issues in Deepwater Ranging Sound Systems.- Generalized Time Space Approach and Convolution Arrays.- Recent Developments in Least Squares Model Fitting.- Modern Empirical Statistical Spectral Analysis.- Passive Sonar Signal Processing.- Adaptive High Resolution Spatial Discrimination of Passive Sources.- On Array Processing in Non-Stationary Random Fields.- Response of Optimal Beamformer to Broad Angular Spectra.- Two-Dimensional Digital Filtering with Applications to Image Processing.- Two-Dimensional Spectral Estimation by Linear Prediction.- Design of Two-Dimensional Digital Filters for Electron Microscopy.- On the Detection of Fluctuating Signals.- Nonparametric Tests for Coherent Detection.- Estimation of Radial Target Length Using High Resolution Signals.- Eigenvector Directions of Spectral Density Matrix: Applications to Characterization of Sources and Modelling of Propagation Media.- Estimation and Tracking of Frequencies of Sinusoids in Noise.- Dynamic Programming for Phase and Frequency Tracking.- The Underwater Medium as a Generalized Communication Channel.- Physical and Descriptive Approaches to Medium-Induced Acoustic Fluctuation.- Characterisation of Submarine Acoustic Transmission Channels.- IV: Computational Background of Signal Processing.- Application of Micro, Mini and Maxi Processors.- High-Speed Programmable Digital Signal Processing Systems for Underwater Research.- Estimates of the Channel Capacity for Acoustic Underwater Communication.- Application of the Coupling of SAW-TO-DIGITAL Technologies to Fast Underwater Signal Processing.- V: Contributions from Other Fields.- Signal Processing in Geophysics.- Radioastronomy.- The Application of Advanced Pattern Recognition Techniques for the Discrimination between Earthquakes and Nuclear Detonations.- Tomographic Ocean Surveillance.- Summaries of Workshops.- Summaries of Workshops.- List of Chairmen.