Spectrum Efficiency in CRNs using Hybrid Dynamic Channel Reservation and Enhanced Dynamic Spectrum Access

Blocking of new arriving services and dropping of ongoing services are inherent problems in Cognitive Radio Networks (CRNs), which need to be addressed to enhance spectrum efficiency. In particular, Secondary Users (SUs) undergo service degradation in the face of Primary Users (PUs)’ arrivals. In this paper, we present a scheme called Efficient Spectrum Utilization (ESU) that reduces the dropping and blocking probabilities of existing and new services, respectively, to make efficient use of the available spectrum. The scheme divides the available spectrum into reserved and non-reserved bands. The reserved band is dynamically allocated a number of channels from the non-reserved band in order to accommodate those services which face interruptions while operating in the non-reserved band. The scheme renders dynamic access to the available spectrum and facilitates priority-based channel allocation and termination. SUs are divided into low and high priority levels depending on their Quality of Service (QoS) requirements. SUs with low priority level are granted direct access to both the bands to enhance channel utilization. SUs operating in the reserved band with high priority levels are granted uninterruptible status to ensure a certain level of service provisioning to SUs. The proposed ESU scheme is modeled using Continuous Time Markov Chain (CTMC) and mathematical expressions are derived for several QoS parameters. Performance of the proposed scheme is evaluated under various network conditions. Results demonstrate that ESU reasonably improves spectrum efficiency under channel failure in CRNs

An ad hoc wireless mobile communications model for Special Operations Forces

The digitization of the battlefield enables special operators to use improved communications supported by computer networks across a range of missions. The communications paradigm is evolving toward mobile wireless ad hoc networks. This development enables an autonomous system of mobile nodes supporting peer-to-peer communications in forward-deployed military networks. Ad hoc networks have to establish a reliable, secure, instant, and usually temporary, communication infrastructure and to be able to access in a global communications infrastructure. Our model describes a global communication network supporting the special operator in mobile wireless communications. The main purpose is to provide a handheld wireless communications node which is capable of transferring voice, data, and imagery to and from parallel and vertical command structures within an environment replete with electronic countermeasures. The model will support the representation of requirements such as throughput, quality of service with low power consumption, and low probability of detection/interception. Special Forces are moving toward using commercial-off-the- shelf products and services based on availability and cost effectiveness. Using GloMoSim tool, we run simulations for a direct action scenario and compared the efficiency of on-demand and table-driven routing protocols under different bandwidths and communications loadshttp://www.archive.org/details/adhocwirelessmob00ogutFirst Lieutenant, Turkish ArmyApproved for public release; distribution is unlimited

Improving the performance of a dismounted Future Force Warrior by means of C4I2SR

This thesis comprises seven peer-reviewed articles and examines systems and applications suitable for increasing Future Force Warrior performance, minimizing collateral damage, improving situational awareness and Common Operational Picture. Based on a literature study, missing functionalities of Future Force Warrior were identified and new ideas, concepts and solutions were created as part of early stages of Systems of Systems creation. These introduced ideas have not yet been implemented or tested in combat and for this reason benefit analyses are excluded. The main results of this thesis include the following: A new networking concept, Wireless Polling Sensor Network, which is a swarm of a few Unmanned Aerial Vehicles forming an ad-hoc network and polling a large number of fixed sensor nodes. The system is more robust in a military environment than traditional Wireless Sensor Networks. A Business Process approach to Service Oriented Architecture in a tactical setting is a concept for scheduling and sharing limited resources. New components to military Service Oriented Architecture have been introduced in the thesis. Other results of the thesis include an investigation of the use of Free Space Optics in tactical communications, a proposal for tracking neutral forces, a system for upgrading simple collaboration tools for command, control and collaboration purposes, a three-level hierarchy of Future Force Warrior, and methods for reducing incidents of fratricide

Diseño de mecanismos para el desarrollo de sistemas seguros con calidad de servicio (QoS)

Seguridad y Calidad de Servicio (QoS) son aspectos ampliamente confrontados. En esta tesis se realiza un análisis detallado de las características y requisitos de seguridad y QoS en las redes candidatas a formar parte de la Internet del Futuro (IF) y de la Internet de los Objetos (IdO), así como de los mecanismos actuales para el análisis de la compensación entre mecanismos de seguridad y QoS. De este estudio se desprende la necesidad de definir nuevos modelos para la evaluación del impacto entre mecanismos de seguridad y QoS, dado que la mayor parte de los estudios centra sus esfuerzos en entornos específicos y características determinadas que no pueden ser fácilmente mapeadas a otros entornos, o cambiar dinámicamente. Por ello definimos un modelo para la composición de esquemas de definición paramétrica basado en el contexto, definido por sus siglas en inglés, Context-based Parametric Relationship Model (CPRM). Este modelo es implementado en una herramienta para la evaluación de mecanismos de Seguridad y QoS (SQT), y su rendimiento evaluado en base a la información integrada en los contextos y la dependencia paramétrica. Finalmente, para mejorar la visualización de los resultados y agilizar la comprensión del modelo definimos un sistema de recomendaciones para la herramienta SQT (SQT-RS). El análisis del modelo y de la herramienta se realiza empleando dos casos base dentro de escenarios del FI: mecanismos de autenticación en redes de sensores (WSN) y recomendaciones para la composición de mecanismos en escenarios de 5G Green sometidos a eavesdropping y jamming

Air Traffic Management Abbreviation Compendium

As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages. In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation

Arquitectura de un sistema C4ISR para pequeñas unidades

La presente tesis doctoral aborda el problema de los sistemas de mando y control, y en concreto los sistemas C4ISR. Los sistemas C4ISr (Command Control, Computers and Communications Information Surveillance and Reconaissance) engloban un amplio número de arquitecturas y sistemas informáticos y de comunicaciones. Su principal finalidad, tanto en aplicaciones civiles como militares, es la de obtener información sobre el estado del teatro de operaciones para entregársela, convenientemente formateada, a las personas al mando de una operación de forma que se construyan una adecuada visión del mismo que les permita tomar las decisiones correctas. Por otra parte, deben servir de plataforma de comunicaciones para transmitir dichas órdenes y cualquier otra información que se estime oportuna. La presente tesis doctoral se centra en identificar las necesidades existentes en mando y control a nivel táctico, tanto en la vertiente civil como en la militar, y plantear una arquitectura global para sistemas C4ISR que permita diseñar, desarrollar e implementar una solución de sistema de mando y control de pequeñas unidades (nivel de batallón e inferiores) para mejorar la conciencia situacional, tanto individual como como compartida, de los comandantes en esos niveles. Se ha promovido el planteamiento de arquitecturas y el desarrollo de sistemas que implementen los novedosos conceptos de mando y control, detectados en la literatura científica reciente, para la consecución de la efectividad en el cumplimiento de una misión, siguiendo la filosofía COTS (Commercial off-the self), enfatizando el uso de estándares en todos sus componentes y una aproximación OSS (open source software) en el desarrollo de componentes software, e integrando fluljos multimedia como una de las principales aportaciones. Para ello se ha realizado un exhaustivo y profundo análisis del estado del arte acerca de los sistemas de mando y control, desde sus comienzos hasta las últimas propuestas. Esto nos ha conducidoPérez Llopis, I. (2009). Arquitectura de un sistema C4ISR para pequeñas unidades [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6067Palanci

Space Cooperation Under Anarchy: Commercialization of Outer Space and Space Security in the Post-Cold War Era

The 20th century brought the most horrific weapons and most devastating wars in the history of human civilization. It also gave us the most breathtaking discoveries and technological breakthroughs, including the opening up of outer space to human reach. The commercialization of outer space is one of the most significant developments of our time, giving us an opportunity to put the richness of this medium to the betterment of human conditions on Earth on an increasingly widening scale. Technological advances have also made space more important militarily. A puzzle now is whether the commercialization of outer space facilitates international cooperation in the security realm or makes interstate relations more competitive in the fourth medium. This study tries to address the issue of outer space security by placing it within the realist-liberal debate on economic interdependence and international conflict and cooperation. It shows that as the post-Cold War transition era drew to its close, security interests of the United States, on the one hand, and Russia and China, on the other, continued to diverge with regard to space security. The sole international intergovernmental organization charged with the negotiations on space security issues failed to bridge the differences and bring about compromises among the major space players. As a result, a new space security regime regulating expanding military uses of space has not emerged. Liberal expectations fail on two important accounts. Firstly, the cost-benefit analysis that lies in the heart of the argument of liberal pacification consists of the costs of fighting a war as well as the opportunity costs of war and the former has not necessarily increased with technological progress and, even with greater commercialization of outer space, the latter may not necessarily offset the trend in the former. Secondly, the liberal expectation that expanding commercial relations between states would gradually lead to progressive de-legitimization of the use force has so far failed to materialize with respect to outer space

Department of Defense Dictionary of Military and Associated Terms

The Joint Publication 1-02, Department of Defense Dictionary of Military and Associated Terms sets forth standard US military and associated terminology to encompass the joint activity of the Armed Forces of the United States. These military and associated terms, together with their definitions, constitute approved Department of Defense (DOD) terminology for general use by all DOD components