Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. ?? 2013 Elsevier B.V. All rights reserved

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Abstract-Cognitive Radio (CR) was designed to support flexible spectrum usage by adding spectrum sensing facilities and decision making logic to the radio devices. Cognitive Radio Network (CRN) is an extension of the CR concept to enable holistic end-to-end optimization of the network operation and services. We discuss CRN management issues in the context of military and tactical operation environments, where the key feature is the temporal nature of the network installations. Our special interest is in the wireless ad hoc network solutions. The network lifetime may extend from just hours to several days. The limited lifetime of the networks makes it both possible and necessary to define the management functionalities with respect to different mission phases. Traditional FCAPS (Fault, Configuration, Administration, Performance, and Security) functions and their required actions are therefore detailed to some level at each operational phase (before, during and after mission). We will emerge the idea that, as the cognitive and autonomous technologies will be developed to operate communication networks and become trustworthy enough to be applied also in tactical context, they will most likely first be applied in the during mission phase. Of course, this phase is also the most critical in the sense that it is here that lives are at stake. To answer this critical issue, the policy management must be seen as an equally critical functionality. It is necessary to develop the interconnection between mission goals and defined policies so that the Cognitive Network Engine (CNE) determining the operational parameters of the network, in all situations provides a reliable and failsafe communication solution to be utilized. 1

In the absence of real-life implementations, this paper attempts to conceptually capture potential benefits and improvements that Cognitive Radio Networks (CRN) could introduce to a military environment. Functional business capability areas, as well as a system model, are used to frame analysis. Military CRNs improve reliability and availability of information flows. These may lead to improved information sharing and situation awareness and eventually to wider adoption of mission command and self-synchronization. However, fundamental capacity benefits of the CRNs remain a research topic. The requirement of computer-aided planning, preparation and simulation environment in support of deployed CRNs could also serve as a research and development platform for a Cognitive Radio System development activity as a collaborative international effort.