392 resultados para GnuRadi,SDR,SDR ADALM-PLUTO
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Mode of access: Internet.
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Cover title.
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The substance of this essay was reprinted in Perticari's Opre, Bologna, 1838-39, ii.155-172.
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Text in Spanish and English.
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Concert Program
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This paper proposes a theoretical explanation of the variations of the sediment delivery ratio (SDR) versus catchment area relationships and the complex patterns in the behavior of sediment transfer processes at catchment scale. Taking into account the effects of erosion source types, deposition, and hydrological controls, we propose a simple conceptual model that consists of two linear stores arranged in series: a hillslope store that addresses transport to the nearest streams and a channel store that addresses sediment routing in the channel network. The model identifies four dimensionless scaling factors, which enable us to analyze a variety of effects on SDR estimation, including (1) interacting processes of erosion sources and deposition, (2) different temporal averaging windows, and (3) catchment runoff response. We show that the interactions between storm duration and hillslope/channel travel times are the major controls of peak-value-based sediment delivery and its spatial variations. The interplay between depositional timescales and the travel/residence times determines the spatial variations of total-volume-based SDR. In practical terms this parsimonious, minimal complexity model could provide a sound physical basis for diagnosing catchment to catchment variability of sediment transport if the proposed scaling factors can be quantified using climatic and catchment properties.
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This paper presents a scientific and technical description of the modelling framework and the main results of modelling the long-term average sediment delivery at hillslope to medium-scale catchments over the entire Murray Darling Basin (MDB). A theoretical development that relates long-term averaged sediment delivery to the statistics of rainfall and catchment parameters is presented. The derived flood frequency approach was adapted to investigate the problem of regionalization of the sediment delivery ratio (SDR) across the Basin. SDR, a measure of catchment response to the upland erosion rate, was modeled by two lumped linear stores arranged in series: hillslope transport to the nearest streams and flow routing in the channel network. The theory shows that the ratio of catchment sediment residence time (SRT) to average effective rainfall duration is the most important control in the sediment delivery processes. In this study, catchment SRTs were estimated using travel time for overland flow multiplied by an enlargement factor which is a function of particle size. Rainfall intensity and effective duration statistics were regionalized by using long-term measurements from 195 pluviograph sites within and around the Basin. Finally, the model was implemented across the MDB by using spatially distributed soil, vegetation, topographical and land use properties under Geographic Information System (GIs) environment. The results predict strong variations in SDR from close to 0 in floodplains to 70% in the eastern uplands of the Basin. (c) 2005 Elsevier Ltd. All rights reserved.
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This paper proposes a new converter protection method, primarily based on a series dynamic resistor (SDR) that avoids the doubly-fed induction generator (DFIG) control being disabled by crowbar protection during fault conditions. A combined converter protection scheme based on the proposed SDR and conventional crowbar is analyzed and discussed. The main protection advantages are due to the series topology when compared with crowbar and dc-chopper protection. Various fault overcurrent conditions (both symmetrical and asymmetrical) are analyzed and used to design the protection in detail, including the switching strategy and coordination with crowbar, and resistance value calculations. PSCAD/EMTDC simulation results show that the proposed method is advantageous for fault overcurrent protection, especially for asymmetrical faults, in which the traditional crowbar protection may malfunction.
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Distributed source coding (DSC) has recently been considered as an efficient approach to data compression in wireless sensor networks (WSN). Using this coding method multiple sensor nodes compress their correlated observations without inter-node communications. Therefore energy and bandwidth can be efficiently saved. In this paper, we investigate a randombinning based DSC scheme for remote source estimation in WSN and its performance of estimated signal to distortion ratio (SDR). With the introduction of a detailed power consumption model for wireless sensor communications, we quantitatively analyze the overall network energy consumption of the DSC scheme. We further propose a novel energy-aware transmission protocol for the DSC scheme, which flexibly optimizes the DSC performance in terms of either SDR or energy consumption, by adapting the source coding and transmission parameters to the network conditions. Simulations validate the energy efficiency of the proposed adaptive transmission protocol. © 2007 IEEE.
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Erősődő igény van a jelenlegi sokoldalú nemzetközi felügyeleti rendszer reformjára úgy, hogy az a nemzeti gazdaságpolitikák nemzetközi hatásait is figyelembe vegye. Ehhez át kell reformálni a jelenlegi globális pénzügyi szabályozási rendszert, de ki kell alakítani a nemzeti gazdaságpolitikák egymásra hatásának koordinációját is. Ide tartozik a globális külső sokkok csillapítására szolgáló anti-ciklikus finanszírozás, a nemzetközi adózási együttműködés fokozása, a nemzetközi adósságfinanszírozás tökéletesítése, vagy a globális fizetésieszköz-tartalékok és a fizetési rendszer viszonya. Ez utóbbi területen az SDR kiterjedtebb használatának feltételeit kell kimunkálni. A jelenlegi globális intézmények – WTO, Nemzetközi Valutaalap, Világbank – alapos megújítása elkerülhetetlen. A globális gazdasági koordináció intézményi kereteinek kidolgozása viszont még várat magára. A G20-ak csoportja – bár fontos reformokat kezdeményezett –, nem tekinthető a világgazdasági egyensúlytalanságok megoldása letéteményesének. A cél csak olyan globális intézményi struktúra lehet, amely egyaránt képes a világ nagy számú gazdaságai közötti koordinációs feladatok megoldására, s a döntések végrehajtásának kikényszerítésére. / === / The present multilateral international surveillance system needs to be reformed with an eye on international repercussions of national economic policies. The present global financial architecture, the coordination of interplays of national economic policies must be modified. An anti-cyclical financing capable of absorbing global external shocks, strengthening of international tax cooperation, improving international debt financing or the relations between global financial reserves and the global payment system might be part and parcel of this process. A more extended use of SDR could be worked out. Reforms of the present global institutions – the WTO, the IMF, the World Bank – cannot be avoided any further. Institutional frameworks of global economic coordination mechanism have still not been worked out. The Group of 20 (G-20) cannot be seen as the sole player in fighting world economic disequlibria. A global institutional system is envisaged, which is able to implement economic coordination among national economic units and to enforce the implementation of decisions taken. At present there is no global institution dealing with coherence and consistency of global issues. Reforming present institutions and/or designing new ones are possible options. The basis for such an international coordination must involve general acceptance of principles, transparent implementation, and enforcement of decisions taken.
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Post-crisis Argentina is a case study of crisis management through debt restructuring. This article examines how Argentina negotiated the external debt in the wake of the sovereign default in December 2001 and now confronts challenges posed by holdout creditors—the so called “vulture funds”. It argues that debt restructuring has put a straitjacket on the national economy, making it virtually impossible for healthy growth short of a break with the international economic order. While Argentina has successfully restructured a $95 billion debt with an unprecedented “hair cut” (around 70% reduction in “net value of debt”), a sustainable growth appears out of reach as long as reliance on the government debt market prevails. In this cycle, the transmission belt of financial crisis to developing countries is characterized by the entry of highly speculative players such as hedge funds, conflicts of interests embedded in “sovereign debt restructuring” (SDR) and vulnerabilities associated with “emerging market debt”.