Enhancing IEEE 802.11 Energy Efficiency for Continuous Media Applications

This paper proposes the Optimized Power save Algorithm for continuous Media Applications (OPAMA) to improve end-user device energy efficiency. OPAMA enhances the standard legacy Power Save Mode (PSM) of IEEE 802.11 by taking into consideration application specific requirements combined with data aggregation techniques. By establishing a balanced cost/benefit tradeoff between performance and energy consumption, OPAMA is able to improve energy efficiency, while keeping the end-user experience at a desired level. OPAMA was assessed in the OMNeT++ simulator using real traces of variable bitrate video streaming applications. The results showed the capability to enhance energy efficiency, achieving savings up to 44% when compared with the IEEE 802.11 legacy PSM.

An IEEE 802.11 energy efficient mechanism for continuous media applications

The widespread deployment of wireless mobile communications enables an almost permanent usage of portable devices, which imposes high demands on the battery of these devices. Indeed, battery lifetime is becoming one the most critical factors on the end-users satisfaction when using wireless communications. In this work, the optimized power save algorithm for continuous media applications (OPAMA) is proposed, aiming at enhancing the energy efficiency on end-users devices. By combining the application specific requirements with data aggregation techniques, {OPAMA} improves the standard {IEEE} 802.11 legacy Power Save Mode (PSM) performance. The algorithm uses the feedback on the end-user expected quality to establish a proper tradeoff between energy consumption and application performance. {OPAMA} was assessed in the OMNeT++ simulator, using real traces of variable bitrate video streaming applications, and in a real testbed employing a novel methodology intended to perform an accurate evaluation concerning video Quality of Experience (QoE) perceived by the end-users. The results revealed the {OPAMA} capability to enhance energy efficiency without degrading the end-user observed QoE, achieving savings up to 44 when compared with the {IEEE} 802.11 legacy PSM.

Fukushima Effects on Media Coverage and Attitudes in Germany

The paper examines the question, in how far Fukushima caused changes in the media coverage and the public opinion about nuclear power in Germany. To answer this question we used two methods, content analysis and survey. Firstly we analysed data from a quantitative content analyses to examine changes in the media coverage about nuclear power between 2010 and 2011. The first investigation period lasted from 10.07.2010 to 04.09.2010, immediately before the German Bundestag vote for the lifetime extension of nuclear power stations. The second investigation period covered the first two months of media coverage after Fukushima from 12.03.2011 to 16.5.2011. Secondly our data consist of a representative telephone panel survey (n=341). As the first wave was carried out from 16.8.2010 to 06.9.2010 and the second wave from 15.5.2011 to 04.06.2011 these data set gives us the unique possibility to investigate attitude changes about nuclear power on the individual level.