837 resultados para Peak to average power ratio (PAPR)


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Includes bibliography.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The United States has exerted a major influence on Southeast Asia, especially since World War II. As both a promoter of neoliberal reform and as the key strategic actor in the wider East Asian region, the impact of U.S. power has been immense. But both the Asian economic crisis and its aftermath, and the more recent war on terror, have highlighted the contradictory impact of evolving U.S. foreign policy and intervention in the region. At both an elite and a mass level there is evidence of resentment about, and hostility toward, U.S. policy and its perceived negative effects. This article outlines how U.S. foreign policy has impacted the region in the economic, political, and security spheres, and argues that not only has it frequently not achieved its goals, but it may in fact be undermining both America's long-term hegemonic position in the region and any prospects for political liberalization.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This letter considers clip-limited transmission over multiple-input multiple-output digital subscriber lines (MIMO-DSL). We show that a recent low complexity, low peak-to-average-ratio (PAR) single-input modulation technique can be applied to the case of multiple cross-talking channels in a bonded-DSL system. Unfortunately however the direct initialization procedure is computationally infeasible. In this paper, we provide a novel low-complexity initialization procedure. Simulations confirm that the proposed approach has superior performance in clip-limited conditions, compared with both discrete matrix multitone and vectored discrete multitone.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective To investigate current use of the internet and eHealth amongst adults. Design Focus groups were conducted to explore participants' attitudes to and reasons for health internet use. Main outcome measures The focus group data were analysed and interpreted using thematic analysis. Results Three superordinate themes exploring eHealth behaviours were identified: decline in expert authority, pervasiveness of health information on the internet and empowerment. Results showed participants enjoyed the immediate benefits of eHealth information and felt empowered by increased knowledge, but they would be reluctant to lose face-to-face consultations with their GP. Conclusions Our findings illustrate changes in patient identity and a decline in expert authority with ramifications for the practitioner–patient relationship and subsequent implications for health management more generally.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Germany has traditionally played a key role in promoting European Union solutions to domestic policy problems. In doing so it gained a reputation as a 'tamed power' (Katzenstein). This article reviews Germany's diplomacy two decades after unification. It explores the 'tamed power' hypothesis with reference to three policy areas: constitutional reform in the EU; Justice and Home Affairs policy; and an issue that has made German European policy very salient of late, the management of the Eurozone. The article argues that Germany has become a much less inclusive actor in European policy, pursuing policy solutions through 'pioneer groups' where these offer greater promise than the EU itself and becoming increasingly attentive to domestic political constraints. The article argues that Germany has become a normalized power, with significant implications for the EU. © 2010 The Author(s). International Affairs © 2010 The Royal Institute of International Affairs.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Distributed Generation (DG) from alternate sources and smart grid technologies represent good solutions for the increase in energy demands. Employment of these DG assets requires solutions for the new technical challenges that are accompanied by the integration and interconnection into operational power systems. A DG infrastructure comprised of alternate energy sources in addition to conventional sources, is developed as a test bed. The test bed is operated by synchronizing, wind, photovoltaic, fuel cell, micro generator and energy storage assets, in addition to standard AC generators. Connectivity of these DG assets is tested for viability and for their operational characteristics. The control and communication layers for dynamic operations are developed to improve the connectivity of alternates to the power system. A real time application for the operation of alternate sources in microgrids is developed. Multi agent approach is utilized to improve stability and sequences of actions for black start are implemented. Experiments for control and stability issues related to dynamic operation under load conditions have been conducted and verified.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Future power systems are expected to integrate large-scale stochastic and intermittent generation and load due to reduced use of fossil fuel resources, including renewable energy sources (RES) and electric vehicles (EV). Inclusion of such resources poses challenges for the dynamic stability of synchronous transmission and distribution networks, not least in terms of generation where system inertia may not be wholly governed by large-scale generation but displaced by small-scale and localised generation. Energy storage systems (ESS) can limit the impact of dispersed and distributed generation by offering supporting reserve while accommodating large-scale EV connection; the latter (load) also participating in storage provision. In this paper, a local energy storage system (LESS) is proposed. The structure, requirement and optimal sizing of the LESS are discussed. Three operating modes are detailed, including: 1) storage pack management; 2) normal operation; and 3) contingency operation. The proposed LESS scheme is evaluated using simulation studies based on data obtained from the Northern Ireland regional and residential network.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper presents a study on the implementation of Real-Time Pricing (RTP) based Demand Side Management (DSM) of water pumping at a clean water pumping station in Northern Ireland, with the intention of minimising electricity costs and maximising the usage of electricity from wind generation. A Genetic Algorithm (GA) was used to create pumping schedules based on system constraints and electricity tariff scenarios. Implementation of this method would allow the water network operator to make significant savings on electricity costs while also helping to mitigate the variability of wind generation.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This research study investigates the application of phase shifter-based smart antenna system in distributed beamforming. It examines the way to optimise the transmit power by jointly maximising the directivity of the array antennas and the weight vector for distributed beamforming. This research study concludes that maximising directivity can lead to better transmit power minimisation compared to maximising field intensity. This study also concludes that signal to noise power ratio maximisation subject to a power constraint and power minimisation subject to a signal to noise power ratio constraint yield the same results.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The current density-voltage (J-V) characteristics of poly(3-methylthiophene) devices show a negative differential resistance (NDR) at room temperature with a large peak to valley current ratio (similar to 507). This NDR can be tuned by two orders of magnitude by controlling the carrier density due to the variation of the space-charge region in the device. The temperature and scan rate dependent J-V measurements infer that the NDR is mainly driven by the trapping and de-trapping of carriers. The photo-generation of carriers is observed to reduce the NDR effect.