57 resultados para Output performances
Resumo:
Public support for private R&D and innovation is part of most national and regional innovation support regimes. In this article, we estimate the effect of public innovation support on innovation outputs in Ireland and Northern Ireland. Three dimensions of output additionality are considered: extensive additionality, in which public support encourages a larger proportion of the population of firms to innovate; improved product additionality, in which there is an increase in the average importance of incremental innovation; new product additionality, in which there is an increase in the average importance of more radical innovation. Using an instrumental variable approach, our results are generally positive, with public support for innovation having positive, and generally significant, extensive, improved and new product additionality effects. These results hold both for all plants and indigenously owned plants, a specific target of policy in both jurisdictions. The suggestion is that grant aid to firms can be effective in both encouraging firms to initiate new innovation and improve the quality and sophistication of their innovation activity. Our results also emphasize the importance for innovation of in-house R&D, supply-chain linkages, skill levels and capital investment, all of which may be the focus of complementary policy initiatives.
Resumo:
The authors use a growth accounting framework to examine growth of the rapidly developing Chinese economy. Their findings support the view that, although feasible in the intermediate term, China's recent pattern of extensive growth is not sustainable in the long run. The authors believe that China will be able to sustain a growth rate of 8 to 9 percent for an extended period if it moves from extensive to intensive growth. They next compare potential growth in China with historical developments in the United States and the European Union. They discuss the differences in production structure and level of development across the three economies that may explain the countries' varied intermediate-term growth prospects. Finally, the authors provide an analysis of "green" gross domestic product and the role of natural resources in China's growth. © 2009, The Federal Reserve Bank of St. Louis.
Resumo:
A significant part of the literature on input-output (IO) analysis is dedicated to the development and application of methodologies forecasting and updating technology coefficients and multipliers. Prominent among such techniques is the RAS method, while more information demanding econometric methods, as well as other less promising ones, have been proposed. However, there has been little interest expressed in the use of more modern and often more innovative methods, such as neural networks in IO analysis in general. This study constructs, proposes and applies a Backpropagation Neural Network (BPN) with the purpose of forecasting IO technology coefficients and subsequently multipliers. The RAS method is also applied on the same set of UK IO tables, and the discussion of results of both methods is accompanied by a comparative analysis. The results show that the BPN offers a valid alternative way of IO technology forecasting and many forecasts were more accurate using this method. Overall, however, the RAS method outperformed the BPN but the difference is rather small to be systematic and there are further ways to improve the performance of the BPN.
Resumo:
Recent landmark experiments have demonstrated how quantum mechanical impurities can be created within strongly correlated quantum gases and used to probe the coherence properties of these systems. Here we present a theoretical model to simulate such an output coupler for a Tonks- Girardeau gas that shows excellent agreement with the experimental results for atom transport and output coupling. The solid theoretical basis our model provides allows us to explore non-equilibrium transport phenomena in ultra-cold quantum gases and leads us to predict a regime of atom blockade, where the impurity component becomes localised in the parent cloud despite the presence of gravity. We show that this provides a stable mixed-species quantum gas in the strongly correlated limit.
Resumo:
In this paper, we address the problem of designing multirate codes for a multiple-input and multiple-output (MIMO) system by restricting the receiver to be a successive decoding and interference cancellation type, when each of the antennas is encoded independently. Furthermore, it is assumed that the receiver knows the instantaneous fading channel states but the transmitter does not have access to them. It is well known that, in theory, minimum-mean-square error (MMSE) based successive decoding of multiple access (in multi-user communications) and MIMO channels achieves the total channel capacity. However, for this scheme to perform optimally, the optimal rates of each antenna (per-antenna rates) must be known at the transmitter. We show that the optimal per-antenna rates at the transmitter can be estimated using only the statistical characteristics of the MIMO channel in time-varying Rayleigh MIMO channel environments. Based on the results, multirate codes are designed using punctured turbo codes for a horizontal coded MIMO system. Simulation results show performances within about one to two dBs of MIMO channel capacity.
Resumo:
Recent cold winters and prolonged periods of low wind speeds have prompted concerns about the increasing penetration of wind generation in the Irish and other northern European power systems. On the combined Republic of Ireland and Northern Ireland system there was in excess of 1.5 GW of installed wind power in January 2010. As the penetration of these variable, non-dispatchable generators increases, power systems are becoming more sensitive to weather events on the supply side as well as on the demand side. In the temperate climate of Ireland, sensitivity of supply to weather is mainly due to wind variability while demand sensitivity is driven by space heating or cooling loads. The interplay of these two weather-driven effects is of particular concern if demand spikes driven by low temperatures coincide with periods of low winds. In December 2009 and January 2010 Ireland experienced a prolonged spell of unusually cold conditions. During much of this time, wind generation output was low due to low wind speeds. The impacts of this event are presented as a case study of the effects of weather extremes on power systems with high penetrations of variable renewable generation.
Resumo:
AND logic gate behaviour can be recognized in chemical-responsive luminescence phenomena concerning small molecules. Though initial developments concerned separate and distinguishable chemical species as inputs, consideration of other types of input sets allows substantial expansion of the sub-field. Dissection of these molecular devices into modules, where possible, enables analysis of their logic behaviour according to supramolecular photochemical mechanisms.
Resumo:
We have studied the effect of prepulses in enhancing the efficiency of generating ASE beams in soft X-ray laser plasma amplifiers based on pumping Ne-like ions, Slab targets were irradiated with a weak prepulse followed by a main plasma heating pulse of nanosecond duration, Time-integrated; time and spectrally resolved and time and angularly resolved lasing emissions on the 3p-3s (J=0-1) XUV lasing lines of Ne-like Ni, Cu and Zn at wavelengths 232 Angstrom 221 Angstrom and 212 Angstrom respectively have been monitored. Measurements were made for pre-pulse/main-pulse intensity ratios from 10(-5)-10(-1) and for pump delay times of 2 ns and 4.5 ns. Zinc is shown to exhibit a peak in output intensity at similar to 2x10(-3) pre-pulse fraction for a 4.5 ns pump delay, with a main pulse pump intensity of similar to 1.3x10(13) W cm(-2) on a 20 mm target. The Zn lasing emission had a duration of similar to 240 ps and this was insensitive to prepulse fraction. The J=0-1 XUV laser output for nickel and copper increased monotonically with prepulse fraction, with copper targets showing least sensitivity to either prepulse level or prepulse to main pulse delay. Under the conditions of the study, the pre-pulse level was observed to haveno significant influence on the output intensity of the 3p-3s (J=2-1) lines of any of the elements investigated.
Resumo:
We report on measurements of the saturated single frequency output of a Ge XXIII x-ray laser on the J=0-->1 transition at 19.6 nm from a refraction compensating double target driven by 150 J of energy from 75-ps Nd-glass laser pulses. The 19.6-nm line completely dominated the laser output. The output energy was measured to be 0.9 mJ in a beam of 6.6x30 mrad(2) divergence, corresponding to a conversion efficiency of 6 x 10(-6).
Resumo:
Amplification of spontaneous emission at 23.6 nm has been studied in a Ge plasma heated by a 1 TW, 1.06 mum wavelength, laser pulse. The exponent of the axial gain reached 21 in a geometry with Fresnel number less-than-or-equal-to 1. Two plasma columns were produced by irradiation of slab targets up to a combined length of 3.6 cm. A narrow band XUV mirror allowed double pass amplification. Saturation of ASE output at 23.6 nm was observed as a change from exponential to linear growth of the output with plasma length. Further evidence of the effect was provided by a decline in the ratio of the output at 23.6 nm to that at 23.2 nm from approximately 1.6: 1 to approximately 0.5: 1, the latter being the theoretically predicted value for saturated operation. The onset of saturation at gL almost-equal-to 15 is consistent with model calculations. The beam divergence was about 8x diffraction limited with a brightness estimated at almost-equal-to 10(14) W/cm2/ster.