This paper describes the results of current research at DREA in which techniques of optimum array processing are being applied to active sonar. We are presenting these results at the Advanced Study Institute in order to illustrate some actual applications for such processing and to point out some of the practical considerations which arise in real systems. In particular, the paper concerns the problems which arise when the individual sensor elements have a complicated directivity pattern themselves. This is a common phenomenon in active systems where the receiving sensors are complex resonant structures and are housed in a dome or towed body presenting various baffling and diffraction effects. Most treatments of array processing consider ideal elements which have well behaved directivity properties and are transparent to the field. The results of this paper show that where these properties are not met, careful in situ array measurements are required, and even with such measurements practical array gains may not be as good as predictions based on ideal sensors.

The summer school held in Portovenere followed a tutorial format with the purpose of familiarizing postdoctoral or postgraduate students in the basic theories and up-to-date applications of present knowledge. Although, from a teaching point of view, a certain areount of overlapping is always useful, in order to avoid excessive duplication direct contact between lecturers expert in the same subject was encouraged during the preparation phase. In recent years computer facilities and theoretical implementa tion have considerably increased the possibility of solving problems relating to signal detection in noise. Any type of communication may take advantage of signal processing principles, including any type of physical measurement that can be considered as a non-semantic and/or quasi-semantic communication. Since signal processing techniques are common to many branches of science (telecommunications, radar, sonar, seismology, geophysics, nuclear research, space research and others), the advanced and sophisticated levels reached singularly in anyone of them could be used to the advantage of the others. In particular, underwater acoustics is a discipline which, to some extent, represents a practical general model that has permitted the development of signal processing techniques suitable to meet data reduction and interpretation needs of other branches of science. This ASI consequently underlined the inter-disciplinarity of signal proces sing in order that the principles of outstanding methods developed in one field may be adapted to others.

Control Applications of Adaptive covers the proceedings of the 197 Workshop on Applications of Adaptive Control, held in Yale University. This book is organized into five parts encompassing 18 chapters that summarize the potential application of adaptive control to many practical problems. Part I contains tutorials that bring together important result s in two of the most studied approaches to adaptive control, namely, self-tuning regulators and model reference adaptive control (MRAC), with a particular emphasis on the importance of error models in the stability analysis of MRAC. Part II examines the algorithms used for adaptive signal processing, while Part III describes the types of power systems problems that could benefit from application of adaptive control and how to apply adaptive control algorithms for controlling large electric generators. Part IV highlights adaptive control in aircraft systems. This part also considers how adaptive control fell into disfavor in the flight control community, illustrating the existence of residual negative bias. The desirability of cost elimination of air data sensors in less-sophisticated flight control systems is also discussed. Part V addresses the application of process control to chemical processes and to electromechanical systems. This part also shows the robustness and superior tracking and regulation properties of model reference adaptive control applied to liquid level control. Discussion on various classes of model reference adaptive controllers in a common framework from the viewpoint of microcomputer implementation is also included. This book will be of value to control system theorists and practitioners.

Underwater acoustic digital signal processing and communications is an area of applied research that has witnessed major advances over the past decade. Rapid developments in this area were made possible by the use of powerful digital signal processors (DSPs) whose speed, computational power and portability allowed efficient implementation of complex signal processing algorithms and experimental demonstration of their performance in a variety of underwater environments. The early results served as a motivation for the development of new and improved signal processing methods for underwater applications, which today range from classical of autonomous underwater vehicles and sonar signal processing, to remote control underwater wireless communications. This book presents the diverse areas of underwater acoustic signal processing and communication systems through a collection of contributions from prominent researchers in these areas. Their results, both new and those published over the past few years, have been assembled to provide what we hope is a comprehensive overview of the recent developments in the field. The book is intended for a general audience of researchers, engineers and students working in the areas of underwater acoustic signal processing. It requires the reader to have a basic understanding of the digital signal processing concepts. Each topic is treated from a theoretical perspective, followed by practical implementation details. We hope that the book can serve both as a study text and an academic reference.

Applied Underwater Acoustics meets the needs of scientists and engineers working in underwater acoustics and graduate students solving problems in, and preparing theses on, topics in underwater acoustics. The book is structured to provide the basis for rapidly assimilating the essential underwater acoustic knowledge base for practical application to daily research and analysis. Each chapter of the book is self-supporting and focuses on a single topic and its relation to underwater acoustics. The chapters start with a brief description of the topic's physical background, necessary definitions, and a short description of the applications, along with a roadmap to the chapter. The subtopics covered within individual subchapters include most frequently used equations that describe the topic. Equations are not derived, rather, assumptions behind equations and limitations on the applications of each equation are emphasized. Figures, tables, and illustrations related to the sub-topic are presented in an easy-to-use manner, and examples on the use of the equations, including appropriate figures and tables are also included. - Provides a complete and up-to-date treatment of all major subjects of underwater acoustics - Presents chapters written by recognized experts in their individual field - Covers the fundamental knowledge scientists and engineers need to solve problems in underwater acoustics - Illuminates, in shorter sub-chapters, the modern applications of underwater acoustics that are described in worked examples - Demands no prior knowledge of underwater acoustics, and the physical principles and mathematics are designed to be readily understood by scientists, engineers, and graduate students of underwater acoustics - Includes a comprehensive list of literature references for each chapter