Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded to work at off-design conditions, where complex flow patterns and cavitation appear, especially in Francis turbines. The draft tube cavitation surge is a hydraulic phenomenon that appears in Francis turbines below and above its Best ...

Wind is the world’s fastest growing electric energy source. Because it is intermittent, though, wind is not used to supply baseload electric power today. Interconnecting wind farms through the transmission grid is a simple and effective way of reducing deliverable wind power swings caused by wind intermittency. As more farms are interconnected in an array, wind speed correlation among sites dec...

The PowerTimer toolset has been developed for use in earlystage, microarchitecture-level power–performance analysis of microprocessors. The key component of the toolset is a parameterized set of energy functions that can be used in conjunction with any given cycle-accurate microarchitectural simulator. The energy functions model the power consumption of primitive and hierarchically composed bui...

In recent decades, developments in the financial sector have played a major role in shaping macroeconomic outcomes in a wide range of countries. Financial developments have reinforced the momentum of underlying economic cycles, and in some cases have led to extreme swings in economic activity and a complete breakdown in the normal linkages between savers and investors. These experiences have le...

A central challenge in asset pricing is the weak connection between stock returns and observable economic fundamentals. We provide evidence that this connection is stronger than previously thought. We use a modified version of the Bry-Boschan algorithm to identify long-run swings in the stock market. We call these swings long-run bull and bear episodes. We find that there is a high correlation ...

Recent years have seen large swings in house prices in many countries. Motivated by housing price variations, proposals for taxing capital gains (nominal or real) on housing have repeatedly been put forth. The idea seems to be that such taxes would curb the redistribution occurring between those owning houses and those trying to get into the market for owner-occupied housing. Our paper shows th...

Abstract In this paper, we demonstrate the importance of the number of wavelength division multiplexing (WDM) channels and the network traffic variability on the dynamics of a cascade of erbium-doped fibre amplifiers (EDFAs) fed by packet traffic in burst mode. The dynamics are determined using a numerical model incorporating time variation effects in the EDFA. Calculations are based on the sol...

Abstract Power systems are subjected to a wide range of small or large disturbances during operating conditions. Power system disturbances such as line switching, generator disconnection and sudden removal of faults causes oscillations in an electrical machine rotor angles that can result in severe power swings. Depending on the protection controls, the system may remain stable or unstable and ...