8,164 research outputs found
Wind turbine condition assessment through power curve copula modeling
Power curves constructed from wind speed and active power output measurements provide an established method of analyzing wind turbine performance. In this paper it is proposed that operational data from wind turbines are used to estimate bivariate probability distribution functions representing the power curve of existing turbines so that deviations from expected behavior can be detected. Owing to the complex form of dependency between active power and wind speed, which no classical parameterized distribution can approximate, the application of empirical copulas is proposed; the statistical theory of copulas allows the distribution form of marginal distributions of wind speed and power to be expressed separately from information about the dependency between them. Copula analysis is discussed in terms of its likely usefulness in wind turbine condition monitoring, particularly in early recognition of incipient faults such as blade degradation, yaw and pitch errors
Income inequality : a summary of the Bank's 1998 Symposium
Income inequality has become an increasingly important public policy issue in industrialized countries in recent years. Although macroeconomic conditions have been favorable in many of these countries, the distribution of income within and across countries has remained uneven. In fact, in several countries, income inequality has risen. As a result, policymakers have become concerned that large segments of the population are not reaping the benefits of economic growth.> To gain a better understanding of these issues, the Federal Reserve Bank of Kansas City sponsored a symposium titled "Income Inequality: Issues and Policy Options" held at Jackson Hole, Wyoming, August 27-29, 1998. The symposium brought together a distinguished group of public officials, academics, and private-sector representatives. The discussion was far-ranging and insightful. As moderator Alice Rivlin noted toward the end of the conference, while there was a divergence of opinion in several areas, there was a consensus that "poverty, deprivation, and lack of opportunity are things that ought to be of great concern to us."> Weiner and Monto summarize the papers and commentary presented at the symposium. The first section reviews the changes in income inequality patterns over the past two decades. The second explores the reasons for these changes. Monetary policy links and the economic impact of distributional change are taken up in the following two sections. The final section considers policy options and summarizes the remarks of an overview panel.Income ; Income distribution
Comparing policy gradient and value function based reinforcement learning methods in simulated electrical power trade
In electrical power engineering, reinforcement learning algorithms can be used to model the strategies of electricity market participants. However, traditional value function based reinforcement learning algorithms suffer from convergence issues when used with value function approximators. Function approximation is required in this domain to capture the characteristics of the complex and continuous multivariate problem space. The contribution of this paper is the comparison of policy gradient reinforcement learning methods, using artificial neural networks for policy function approximation, with traditional value function based methods in simulations of electricity trade. The methods are compared using an AC optimal power flow based power exchange auction market model and a reference electric power system model
Generalised CP and Family Symmetry
We perform a comprehensive study of family symmetry models based on
combined with the generalised CP symmetry . We investigate the
lepton mixing parameters which can be obtained from the original symmetry
breaking to different remnant symmetries in the
neutrino and charged lepton sectors. We find that only one case is
phenomenologically viable, namely in the neutrino sector and in the charged lepton sector, leading to the
prediction of no CP violation, namely and the Majorana phases
and are all equal to either zero or . We then
propose an effective supersymmetric model based on the symmetry in which trimaximal lepton mixing is predicted together with
either zero CP violation or with non-trivial
Majorana phases. An ultraviolet completion of the effective model yields a
neutrino mass matrix which depends on only three real parameters. As a result
of this, all three CP phases and the absolute neutrino mass scale are
determined, the atmospheric mixing angle is maximal, and the Dirac CP can
either be preserved with or maximally broken with
and sharp predictions for the Majorana phases and
neutrinoless double beta decay.Comment: 38 pages, 3 figure
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