Scuba Diving Hand Signals Underwater Communication Pocket Companion For Recreational Scuba Divers

Author: Lars Behnke
Publisher: CreateSpace Independent Publishing Platform
ISBN: 1502488485
Size: 29.60 MB
Format: PDF
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Proficiency in underwater communication is not only a vital part of scuba diving training, it also makes diving a much more enjoyable and safer experience. Scuba Diving Hand Signals intends to support beginning recreational scuba divers in learning underwater communication via hand signals. More than 240 commonly used gestures are illustrated and grouped into eight categories:
  • Common signals
  • Problem and emergency signals
  • Training signals
  • Air pressure and number signals
  • Underwater wildlife signals
  • Environment signals
  • Emotion signals
  • Miscellaneous signals
Underwater wildlife signals are supplemented with images of each indicated animal and useful information about its features, distribution, and human interactions.

Digital Underwater Acoustic Communications

Author: Lufen Xu
Publisher: Academic Press
ISBN: 0128030097
Size: 36.86 MB
Format: PDF
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Digital Underwater Acoustic Communications focuses on describing the differences between underwater acoustic communication channels and radio channels, discusses loss of transmitted sound in underwater acoustic channels, describes digital underwater acoustic communication signal processing, and provides a comprehensive reference to digital underwater acoustic communication equipment.

This book is designed to serve as a reference for postgraduate students and practicing engineers involved in the design and analysis of underwater acoustic communications systems as well as for engineers involved in underwater acoustic engineering.

  • Introduces the basics of underwater acoustics, along with the advanced functionalities needed to achieve reliable communications in underwater environment
  • Identifies challenges in underwater acoustic channels relative to radio channels, underwater acoustic propagation, and solutions
  • Shows how multi-path structures can be thought of as time diversity signals
  • Presents a new, robust signal processing system, and an advanced FH-SS system for multimedia underwater acoustic communications with moderate communication ranges (above 20km) and rates (above 600bps)
  • Describes the APNFM system for underwater acoustic communication equipment (including both civil and military applications), to be employed in active sonar to improve its performance

Underwater Communications Synthesis Lectures On Communications

Author: Marco Lanzagorta
Publisher: Morgan & Claypool Publishers
ISBN: 160845844X
Size: 72.25 MB
Format: PDF, ePub, Docs
View: 6739
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Underwater vehicles and underwater moorings are increasing in tactical importance. As such, it is critical to have a robust and secure communication system connecting underwater vehicles on a long seaborne mission and a ground station. As a matter of fact, the deployment of efficient communication links with underwater vehicles is one of the greatest technological challenges presently confronted by the world's naval forces.

To circumvent most of the limitations involved in the use of RF or acoustic channels for perfectly secure communications with underwater vehicles, it is worth considering the feasibility of an optical channel to facilitate a two-way satellite communication link secured via perfectly secure ciphers enabled by a quantum key distribution protocol.

This book offers a concise review of underwater communications systems. Our approach is pedagogical, making a strong emphasis on the physics behind the attenuating properties of the oceanic environment and the propagation of electromagnetic signals in the ELF, VLF, and optical bands. We assume the reader is familiar with the basic principles of classical electrodynamics and optics.

The system design, components, and noise analysis of an underwater optical communications device are discussed in detail. Furthermore, we offer simulations of the performance of the communication system for different types of ocean waters. Our final conclusion is that it appears to be feasible to design and build underwater communications using optical classical and quantum channels secured with quantum key distribution protocols.

Table of Contents: Introduction / Electrodynamics of Attenuating Media / Underwater Communication Channels / Underwater Optical Communications: Technology / Underwater Optical Communications: Noise Analysis / Underwater Optical Communications: System Performance / Underwater Quantum Communications / Conclusions


Ofdm For Underwater Acoustic Communications

Author: Shengli Zhou
Publisher: Wiley
ISBN: 1118458869
Size: 62.89 MB
Format: PDF, Docs
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A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development

This book, which is the first to describe the processing techniques central to underwater OFDM, is arranged into four distinct sections: First, it describes the characteristics of underwater acoustic channels, and stresses the difference from wireless radio channels. Then it goes over the basics of OFDM and channel coding. The second part starts with an overview of the OFDM receiver, and develops various modules for the receiver design in systems with single or multiple transmitters. This is the main body of the book. Extensive experimental data sets are used to verify the receiver performance. In the third part, the authors discuss applications of the OFDM receiver in i) deep water channels, which may contain very long separated multipath clusters, ii) interference-rich environments, where an unintentional interference such as Sonar will be present, and iii) a network with multiple users where both non-cooperative and cooperative underwater communications are developed. Lastly, it describes the development of a positioning system with OFDM waveforms, and the progress on the OFDM modem development. Closely related industries include the development and manufacturing of autonomous underwater vehicles (AUVs) and scientific sensory equipment. AUVs and sensors in the future could integrate modems, based on the OFDM technology described in this book.

Contents includes: Underwater acoustic channel characteristics/OFDM basics/Peak-to-average-ratio control/Detection and Doppler estimation (Doppler scale and CFO)/Channel estimation and noise estimation/A block-by-block progressive receiver and performance results/Extensions to multi-input multi-output OFDM/Receiver designs for multiple users/Cooperative underwater OFDM (Physical layer network coding and dynamic coded cooperation)/Localization with OFDM waveforms/Modem developments

A valuable resource for Graduate and postgraduate students on electrical engineering or physics courses; electrical engineers, underwater acousticians, communications engineers


Cooperative Ofdm Underwater Acoustic Communications Wireless Networks

Author: Xilin Cheng
Publisher: Springer
ISBN: 3319332066
Size: 14.62 MB
Format: PDF, Docs
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Following underwater acoustic channel modeling, this book investigates the relationship between coherence time and transmission distances. It considers the power allocation issues of two typical transmission scenarios, namely short-range transmission and medium-long range transmission. For the former scenario, an adaptive system is developed based on instantaneous channel state information. The primary focus is on cooperative dual-hop orthogonal frequency division multiplexing (OFDM).
This book includes the decomposed fountain codes designed to enable reliable communications with higher energy efficiency. It covers the Doppler Effect, which improves packet transmission reliability for effective low-complexity mirror-mapping-based intercarrier interference cancellation schemes capable of suppressing the intercarrier interference power level. 
Designed for professionals and researchers in the field of underwater acoustic communications, this book is also suitable for advanced-level students in electrical engineering or computer science.


What A Fish Knows The Inner Lives Of Our Underwater Cousins

Author: Jonathan Balcombe
Publisher: Scientific American / Farrar, Straus and Giroux
ISBN: 0374288216
Size: 19.43 MB
Format: PDF
View: 5551
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A New York Times Bestseller

Do fishes think? Do they really have three-second memories? And can they recognize the humans who peer back at them from above the surface of the water? In What a Fish Knows, the myth-busting ethologist Jonathan Balcombe addresses these questions and more, taking us under the sea, through streams and estuaries, and to the other side of the aquarium glass to reveal the surprising capabilities of fishes. Although there are more than thirty thousand species of fish―more than all mammals, birds, reptiles, and amphibians combined―we rarely consider how individual fishes think, feel, and behave. Balcombe upends our assumptions about fishes, portraying them not as unfeeling, dead-eyed feeding machines but as sentient, aware, social, and even Machiavellian―in other words, much like us.
What a Fish Knows draws on the latest science to present a fresh look at these remarkable creatures in all their breathtaking diversity and beauty. Fishes conduct elaborate courtship rituals and develop lifelong bonds with shoalmates. They also plan, hunt cooperatively, use tools, curry favor, deceive one another, and punish wrongdoers. We may imagine that fishes lead simple, fleeting lives―a mode of existence that boils down to a place on the food chain, rote spawning, and lots of aimless swimming. But, as Balcombe demonstrates, the truth is far richer and more complex, worthy of the grandest social novel.
Highlighting breakthrough discoveries from fish enthusiasts and scientists around the world and pondering his own encounters with fishes, Balcombe examines the fascinating means by which fishes gain knowledge of the places they inhabit, from shallow tide pools to the deepest reaches of the ocean.
Teeming with insights and exciting discoveries, What a Fish Knows offers a thoughtful appraisal of our relationships with fishes and inspires us to take a more enlightened view of the planet’s increasingly imperiled marine life. What a Fish Knows will forever change how we see our aquatic cousins―the pet goldfish included.


Underwater Signal And Data Processing

Author: Joseph C. Hassab
Publisher: CRC Press
ISBN: 0849368006
Size: 38.44 MB
Format: PDF, ePub, Docs
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A systematic and integrated account of signal and data processing with emphasis on the distinctive marks of the ocean environment is provided in this informative text. Underwater problems such as space-time processing relations vs. disjointed ones, processing of passive observations vs. active ones, time delay estimation vs. frequency estimation, channel effects vs. transparent ones, integrated study of signal, data, and channel processing vs. separate ones, are highlighted. The book provides the beginner with a concise presentation of the essential concepts, defines the basic computational steps, and gives the mature reader an advanced view of underwater systems and the relationships among their building blocks. It presents the needed topics on applied estimation theory within the underwater systems context. Included are topics in linear and nonlinear filtering, spectral analysis, generalized correlation, cepstrum and complex demodulation, Cramer-Rao Bounds, maximum likelihood, weighted least-squares, Kalman filtering, expert systems, wave propagation and their use, as well as their performance in applications to canonical ocean problems. The applications center on the definition, analysis, and solution implementations to representative underwater signal analysis problems dealing with signals estimation, their location and motion. The potential limitations and pitfalls of the implementations are delineated in homogeneous, noisy, interfering, inhomogeneous, multipath, distortions, and/or dispersive channels.

Underwater Electroacoustic Transducers A Handbook For Users And Designers

Author: Dennis Stansfield
Publisher: Peninsula Pub
ISBN: 0932146724
Size: 14.23 MB
Format: PDF, Mobi
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This reprint is a practical handbook for users and designers of underwater transducers. It has been an authoritative text in the field since first published by the Bath University Press in 1991. Design methods are illustrated by concentrating on the design of piezoelectric transducers in the 2 - 20 kHz range, most commonly used in sonar systems. Designs for frequencies below this range are also discussed. Treatment is down-to-earth and avoids complex mathematics. Topics include the role of the transducer as an element of the complete system; wide bandwidth, high power transmitter applications; wide band hydrophones; characteristics of piezoelectric and magnetostrictive materials; and transducer testing. For the user, the wide range of topics and practical approach of the book help him to identify the most important features of the requirement and assist him in drawing up realistic specifications. For the designer, the book describes the necessary theoretical and practical aspects involved in developing a transducer to most effectively suit the application and it discusses the main features of the various types of designs.

Scuba Talk A Guide To Underwater Communication Florida Bahamas And Caribbean Edition

Author: Keith A. Ellenbogen
Publisher: Blue Reef Pubns Inc
ISBN: 0964540746
Size: 61.10 MB
Format: PDF, ePub, Mobi
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Two communicate underwater a diver needs one of two things, expensive underwater communication equipment or a creative imagination. Scuba Talk has solved the problem with a system of hand signals to relay the sighting of marine life with speed, ease and accuracy. This book provides a diagram of each hand signal, which is accompanied by a spectacular color photograph, useful facts, plus diving advice for commonly seen aquatic animals in the Florida, Bahamas and Caribbean region.

Underwater Communications

Author: Marco Lanzagorta
Publisher: Morgan & Claypool Publishers
ISBN: 160845844X
Size: 38.84 MB
Format: PDF, Kindle
View: 3459
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As a matter of fact, the deployment of efficient communication links with underwater vehicles is one of the greatest technological challenges presently confronted by the world's naval forces.To circumvent most of the limitations involved in ...

Digital Underwater Acoustic Communications

Author: Lufen Xu
Publisher: Academic Press
ISBN: 0128030291
Size: 20.64 MB
Format: PDF, ePub, Docs
View: 4157
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This book is designed to serve as a reference for postgraduate students and practicing engineers involved in the design and analysis of underwater acoustic communications systems as well as for engineers involved in underwater acoustic ...

Ofdm For Underwater Acoustic Communications

Author: Shengli Zhou
Publisher: John Wiley & Sons
ISBN: 1118693817
Size: 37.37 MB
Format: PDF
View: 1768
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A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development This book, which is the first to describe the processing techniques central to ...