Fréttir frá Fjarskiptahandbókin.is
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Fréttir frá Fjarskiptahandbókin.is
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Í síðustu viku settu tæknimenn Vodafone upp tvo nýja UHF-endurvarpa fyrir Digital Ísland á vesturlandi. Þeir eru: 1. Í Girðisholti...
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GlobalSpec - Engineering News - Electrical Engineering
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Publication year: 2012Source: Energy, Available online 24 January 2012Andreja?Nemet, Ji?? Jarom?r?Kleme?, Petar Sabev?Varbanov, Zdravko?KravanjaA problem when exploiting renewable energy sources, such as wind and solar radiation, is their fluctuating availability. In the presented work, the Heat Integration methodology for batch processes based on Time Slices has been extended to cover the integration of solar thermal energy, thus allowing for dealing with such variations. A procedure for identifying the number and durations of Time Slices for a problem featuring variable renewable energy supply has been formulated, and developed for solar energy utilisation. The main procedural steps involve partitioning of the measured/forecasted heat availability profile using a large number of candidate time boundaries, and then approximating it by a piecewise-constant profile using high-precision. The approximation profile is obtained by subjecting the candidate superset of time-boundaries to MILP optimisation, thus minimising integral inaccuracy compared to the forecasted availability profile. The Time Slice definitions are completed by approximating the heat loads within the Time Slices. The integration of solar thermal energy can be performed for the specified Time Slice, after the optimal number of Time Slices with approximated constant load has been selected. Using heat storage, the heat can be transferred between Time Slices.
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Publication year: 2012Source: Energy, Available online 24 January 2012Zhanfeng?Song, Tingna?Shi, Changliang?Xia, Wei?ChenA novel adaptive current controller for DFIG-based wind turbines is introduced in this paper. The attractiveness of the proposed strategy results from its ability to actively estimate and actively compensate for the plant dynamics and external disturbances in real time. Thus, the control strategy can successfully drive the rotor current to track the reference value, ensuring that the performance degradation caused by grid disturbances, cross-coupling terms and parameter uncertainties can be successfully suppressed. Besides, the two-parameter tuning feature makes the control strategy practical and easy to implement in commercial wind turbines. To quantify the controller performances, the transfer function description of the controller is derived. General disturbance rejection, robustness against parameter uncertainties, bandwidth and stability are also addressed. Simulation results, together with the time-domain responses, proved the stability and the strong robustness of the control system against parameter uncertainties and grid disturbances. Significant tracking and disturbance rejection performances are achieved.Highlights? The controller can compensate for plant dynamics and external disturbances. ? Performance degradation caused by disturbance can be successfully suppressed. ? General disturbance rejection of the proposed strategy is addressed. ? The stability and the strong robustness of the control system are proved.
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Get all your AV news here from infoComm iQ
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Apantac continues to expands its line of MT HOOD and MAZAMA signal processing and extension solutions and is launching ten new products at ISE, stand 11 N67.   New
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CERRITOS, Calif., Jan 19, 2012 — Elite Screens, Inc. an innovative company that specializes in quality projection screens, today announced that its MaxWhite, MaxWhite FG and Versawhite
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Engadget
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Engadget
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What happens when you take a PogoPlug, add 8GB of flash storage, some radios (WiFi, GPS) and perhaps a few sensors, then stuff everything in a 3D-printed box? You get the F-BOMB (Falling or Ballistically-launched Object that Makes Backdoors), a battery-powered surveillance computer that costs less than $50 to put together using off-the-shelf parts. The 4 x 3.5 x 1-inch device, created by security researcher Brendan O'Connor and funded by DARPA's Cyber Fast Track program, is cheap enough for single-use scenarios where costly traditional hardware is impractical. It can be dropped from an AR Drone, tossed over a fence, plugged into a wall socket or even hidden inside a CO detector. Once in place, the homebrew Linux-based system can be used to gather data and hop onto wireless networks using WiFi-cracking software. Sneaky. Paranoid yet? Click on the source link below for more info.

F-BOMB $50 surveillance computer hides in your CO detector, cracks your WiFi originally appeared on Engadget on Sat, 28 Jan 2012 08:07:00 EDT. Please see our terms for use of feeds.

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