Abstract Drawdown/regret times feature prominently in optimal stopping problems, statistics (CUSUM procedure), and mathematical finance (Russian options). Recently it was discovered that a first passage theory with more general drawdown times, which generalize classic ruin may be explicitly developed for spectrally negative Lévy processes [9, 20]. In this paper we further examine the drawdown-r...

The 4-year drawdown of Horsetooth Reservoir, Colorado, for dam maintenance, provides a case study analog of vegetation response on sediment that might be exposed from removal of a tall dam. Early vegetation recovery on the exposed reservoir bottom was a combination of (1) vegetation colonization on bare, moist substrates typical of riparian zones and reservoir sediment of shallow dams and (2) a...

Experimental hydraulic heads and electrical (self-potential) signals associated with a pumping test were used in an inverse model to estimate the transmissivity distribution of a real aquifer. Several works reported in the literature show that there is a relatively good linear relationship between the hydraulic heads in the aquifer and electrical signals measured at the ground surface. In this ...

When facing the challenge of developing an individual that best fits its environment, nature demonstrates an interesting combination of two fundamentally different adaptive mechanisms: genetic evolution and phenotypic plasticity. Following numerous computational models, it has become the accepted wisdom that lifetime acclimation (e.g. via learning) smooths the fitness landscape and consequently...

The question of optimal portfolio is addressed. The conventional Markowitz portfolio optimisation is discussed and the shortcomings due to non-Gaussian security returns are outlined. A method is proposed to minimise the likelihood of extreme non-Gaussian drawdowns of the portfolio value. The theory is called leptokurtic, because it minimises the effects from ”fat tails” of returns. The leptokur...

Aquifer information carried by aquifer test data may be affected by the presence of a finite thickness skin around the wellbore. The mathematical treatment for an aquifer accounting for the skin zone can be characterized by five parameters, that is, the outer radius of the skin zone and the transmissivity and storativity for each of the skin and aquifer zones. Sensitivity analysis was performed...

The present study examined the effect of the geometric parameters of the Rockfill dams on the 2D static analysis of slope stability. In this regard, several numerical models analyzed for eight heights, three slopes of upstream and downstream, three vertical and skewed core thicknesses and four different impounding time stages namely, "End of Construction", "Full Reservoir", "Half Full Reservoir...