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.
Jane's World Railways covers the railway systems in nearly 140 countries and states worldwide. System details include: key personnel, political background, organisations, financial status, current operations, planned developments, and traction and rolling-stock data. There is also an extensive range of detailed maps and images, all regularly updated. Contact details are given for 2,000 manufacturers, suppliers and service companies, including descriptions of their services and equipment. Key contents include: organisational structures; traffic and revenue statistics; rollingstock fleet data; principal infrastructure details of networks; manufacturers of locomotives and passenger vehicles; diesel engines, transmission and fuelling systems; electric traction equipment; passenger coach equipment; freight vehicles and equipment; brakes and draw gear; bogies and suspension, wheels, axles and bearings; simulation and training systems; signalling and communication systems; passenger information systems; revenue collection systems and station equipment; electrification contractors and equipment suppliers; cables and cable equipment; permanent way components, equipment and services; freight yard and terminal equipment; vehicle maintenance equipment and services; turnkey systems contractors; information technology systems; rolling-stock leasing companies; consultancy services; railway associations and agencies.
Whilst maritime studies tend to reflect the dominance of large navies, history shows how relatively small naval forces can have a disproportionately large impact on global events. From Confederate commerce raiders in the nineteenth century, to Somali pirates today, even the most minor of maritime forces can become a key player on a global stage. Examining a broad range of examples, this volume addresses the roles and activities of small navies in the past and the present at the national, regional and international level. In particular, it focusses on the different ways in which such forces have identified and addressed national and international security challenges and the way in which they interact with other navies and security agencies. In addition the collection also investigates the relationship of such navies with non-governmental organisations, institutions and bodies in pursuit of broader maritime goals, be they political, financial or environmental. Adopting an interdisciplinary approach drawing on the best new research from the fields of international relations, security studies, strategic studies and maritime history, the book examines the diversity of experience amongst different smaller navies and also establishes areas of similarity. Divided into two sections, part one begins with a number of chapters that are theoretical in nature, whilst part two provides case studies that offer a more regional focus, including analysis of the challenges facing contemporary navies and historical case studies designed to reveal the experience of small navies over time. By adopting an approach that combines historical considerations with analysis of current events, the collection offers a unique perspective on the role that small navies have played in wider nautical affairs and their continued impact upon global maritime strategies.
The authority on aircraft under development or in production This unparalleled reference to the world's aircraft provides you with independent cataloguing of all known powered aircraft under development or in production worldwide.
Which military missions for unmanned undersea vehicles (UUVs) appear most promising to pursue in terms of military need, operational and technical risks, alternatives, and cost? To answer this question, the authors assess risks associated with using UUVsfor advocated missions, identify non-UUV alternatives that may be more appropriate for such missions, and analyze potential costs associated with UUV development and use. They conclude that seven missions: mine countermeasures, deployment of leave-behindsurveillance sensors or sensor arrays, near-land and harbor monitoring, oceanography, monitoring undersea infrastructure, anti-submarine warfare tracking, and inspection/identification - appear most promising. Among other recommendations, the authors suggest that the U.S. Navy consolidate its unmanned system master plans and establish relevant priorities in coordination with the Office of the Secretary of Defense. Increased emphasis on the use of surface platforms rather than submarines as host platformsis recommended.