10 research outputs found

    AWARE: Platform for Autonomous self-deploying and operation of Wireless sensor-actuator networks cooperating with unmanned AeRial vehiclEs

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    This paper presents the AWARE platform that seeks to enable the cooperation of autonomous aerial vehicles with ground wireless sensor-actuator networks comprising both static and mobile nodes carried by vehicles or people. Particularly, the paper presents the middleware, the wireless sensor network, the node deployment by means of an autonomous helicopter, and the surveillance and tracking functionalities of the platform. Furthermore, the paper presents the first general experiments of the AWARE project that took place in March 2007 with the assistance of the Seville fire brigades

    Experimental demonstration of a macroscopic cryptography technique

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    Physical layer cryptography offers the unique possibility of certifiably secure data transmission between remote locations. We present here for the first time, to our knowledge, the experimental results of a secure full Poincare occupancy polarization encrypted data transmission system. The scheme uses an approach to macroscopic physical layer cryptography based on combining a multilevel polarisation modulation cipher with a differential phase shift keying data transmission technique. Depolarized noise is added to the encrypted data so as to hide both the data and key from a potential eavesdropper. Experimental results prove the effectiveness of the technique over amplified optical transmission links. The technique hence opens up new avenues for long distance secure data transmission over fibre link

    Stokes encrypted secure communication over optically amplified links

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    The authors describe an innovative polarization-based optical fibre physical layer cryptography technique capable of highly secure data transmission over amplified optical links. It offers completely opaque communication over trans-oceanic distances, gigabit date rates and multiple wavelength

    An inverse method for determining source characteristics for emergency response applications

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    Following a malicious or accidental atmospheric release in an outdoor environment it is essential for first responders to ensure safety by identifying areas where human life may be in danger. For this to happen quickly, reliable information is needed on the source strength and location, and the type of chemical agent released. We present here an inverse modelling technique that estimates the source strength and location of such a release, together with the uncertainty in those estimates, using a limited number of measurements of concentration from a network of chemical sensors considering a single, steady, ground-level source. The technique is evaluated using data from a set of dispersion experiments conducted in a meteorological wind tunnel, where simultaneous measurements of concentration time series were obtained in the plume from a ground-level point-source emission of a passive tracer. In particular, we analyze the response to the number of sensors deployed and their arrangement, and to sampling and model errors. We find that the inverse algorithm can generate acceptable estimates of the source characteristics with as few as four sensors, providing these are well-placed and that the sampling error is controlled. Configurations with at least three sensors in a profile across the plume were found to be superior to other arrangements examined. Analysis of the influence of sampling error due to the use of short averaging times showed that the uncertainty in the source estimates grew as the sampling time decreased. This demonstrated that averaging times greater than about 5min (full scale time) lead to acceptable accuracy

    Recognition of complex human behaviours using 3D imaging for intelligent surveillance applications

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    We introduce a system that exploits 3-D imaging technology as an enabler for the robust recognition of the human form. We combine this with pose and feature recognition capabilities from which we can recognise high-level human behaviours. We propose a hierarchical methodology for the recognition of complex human behaviours, based on the identification of a set of atomic behaviours, individual and sequential poses (e.g. standing, sitting, walking, drinking and eating) that provides a framework from which we adopt time-based machine learning techniques to recognise complex behaviour patterns

    Enhanced transmission techniques

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    Next generation Passive Optical Networks (ngPONs) that offer increased bandwidth and distance-reach to a higher number of customers may require some modifications in the network infrastructure and in the technology of its devices. Nevertheless, these changes should not require a significant increased cost nor upgrading complexity. Optical Network Units (ONUs) at customer premises of currently deployed PONs include a fixed laser at a non-controlled wavelength, launching the light into the upstream fibre or into a single fibre via a coarse WDM multiplexer. In future PONs, Wavelength division multiplexing (WDM) can be effectively used to upgrade the overall PON capacity in several ways. Thus, new generation ONUs may be wavelength-controlled, wavelength-tuneable or wavelength-agnostic. WDM allows superposing different TDMA PONs over the access fibre line. The number of wavelengths then corresponds to two times the number of TDMA PON systems. This solution offers desirable characteristics for an access infrastructure as the use of one single fibre for both upstream and downstream transmission reduces the network size and connection complexity

    Enhanced transmission techniques

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    \u3cp\u3eNext generation Passive Optical Networks (ngPONs) that offer increased bandwidth and distance-reach to a higher number of customers may require some modifications in the network infrastructure and in the technology of its devices. Nevertheless, these changes should not require a significant increased cost nor upgrading complexity. Optical Network Units (ONUs) at customer premises of currently deployed PONs include a fixed laser at a non-controlled wavelength, launching the light into the upstream fibre or into a single fibre via a coarse WDM multiplexer. In future PONs, Wavelength division multiplexing (WDM) can be effectively used to upgrade the overall PON capacity in several ways. Thus, new generation ONUs may be wavelength-controlled, wavelength-tuneable or wavelength-agnostic. WDM allows superposing different TDMA PONs over the access fibre line. The number of wavelengths then corresponds to two times the number of TDMA PON systems. This solution offers desirable characteristics for an access infrastructure as the use of one single fibre for both upstream and downstream transmission reduces the network size and connection complexity.\u3c/p\u3
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