Designing and Implementing Future Aerial Communication Networks

Providing "connectivity from the sky" is the new innovative trend in wireless communications. High and low altitude platforms, drones, aircrafts and airships are being considered as the candidates for deploying wireless communications complementing the terrestrial communication infrastructure. In this article, we report the detailed account of the design and implementation challenges of an aerial network consisting of LTE Advanced (LTE-A) base stations. In particular, we review achievements and innovations harnessed by an aerial network composed of Helikite platforms. Helikites can be raised in the sky to bring Internet access during special events and in the aftermath of an emergency. The trial phase of the system mounting LTE-A technology onboard Helikites to serve users on the ground showed not only to be very encouraging but that such a system could offer even a longer lasting solution provided that inefficiency in powering the radio frequency equipment in the Helikite can be overcome.Comment: IEEE Communications Magazine 201

A Small but Efficient Collaboration for the Spiral2 Control System Development

http://accelconf.web.cern.ch/AccelConf/ICALEPCS2013/papers/tucobab01.pdfThe Spiral2 radioactive ion beam facility to be commissioned in 2014 at Ganil (Caen) is built within international collaborations. This also concerns the control system development shared by three laboratories: Ganil has to coordinate the control and automated systems work packages, CEA/IRFU is in charge of the "injector" (sources and low energy beam lines) and the LLRF, CNRS/IPHC provides the emittancemeters and a beam diagnostics platform. Besides the technology Epics based, this collaboration, although being handled with a few people, nevertheless requires an appropriate and tight organization to reach the objectives given by the project. This contribution describes how, started in 2006, the collaboration for controls has been managed both from the technological point of view and the organizational one, taking into account not only the previous experience, technical background or skill of each partner, but also their existing working practices and "cultural" approaches. A first feedback comes from successful beam tests carried out at Saclay and Grenoble; a next challenge is the migration to operation, Ganil having to run Spiral2 as the other members are moving to new projects

Asal-usul manusia: menurut bibel Al-quran sains

buku ini menjelaskan tentang asal-usul munculnya manusia berdasarkan bible Al-quran250 hal.; 21 c

Asal-usul manusia: menurut bibel Al-quran sains

buku ini menjelaskan tentang asal-usul munculnya manusia berdasarkan bible Al-quran250 hal.; 21 c

Pengetahuan modern dalam Qur'an

xii, hal.13-200; 21c

Capacity evaluation of aerial LTE base-stations for public safety communications

Aerial-Terrestrial communication networks able to provide rapidly-deployable and resilient communications capable of offering broadband connectivity are emerging as a suitable solution for public safety scenarios. During natural disasters or unexpected events, terrestrial infrastructure can be seriously damaged or disrupted due to physical destruction of network components, disruption in subsystem interconnections and/or network congestion. In this context, Aerial-Terrestrial communication networks are intended to provide temporal large coverage with the provision of broadband services at the disaster area. This paper studies the performance of Aerial UMTS Long Term Evolution (LTE) base stations in terms of coverage and capacity. Network model relies on appropriate channel model, LTE 3GPP specifications and well known schedulers are used. The results show the effect of the temperature, bandwidth, and scheduling discipline on the system capacity while at the same time coverage is investigated in different public safety scenarios

Correlating the rheological and mechanical response of polyurethane nanocomposites containing hyperbranched polymers

Cast polyurethane thermosets have been modified with randomly oriented exfoliated and intercalated montmorillonite clay usinghyperbranched polymers (HBP) as reactive additives to promote dispersion of the clay platelets. The influence of the clay content on thestiffness of the nanocomposites is discussed in terms of simplified classical micromechanical models that allow correlations to be establishedbetween the properties of the final polyurethane and the limiting high strain rate shear viscosity of the HBP or HBP/polyethylene glycolnanocomposite precursors. Such models imply certain restrictions on the potential for mechanical reinforcement with unoriented plateletsowing to crowding effects. Moreover, they appear unable to account simultaneously for the observed degrees of reinforcement in the glassyand the rubbery states, if currently accepted values for the stiffness of the MMT are assumed. Possible reasons for this are discussed