abstract spi is based on fitting a gamma distribution to precipitation amounts in selected periods. based on current research, the gamma distribution may not be fitted to annual precipitation of some regions. in order to evaluate this subject, annual precipitation have been used during 1958- 2007 at 11 synoptic stations in iran. in first step, values of spi and frequency of different classes of...

Abstract We investigated the probability distributions of sunspot area and magnetic flux by using data from Royal Greenwich Observatory USAF/NOAA. constructed a sample 2995 regions with maximum-development areas ≥500 MSH (millionths solar hemisphere), covering 146.7 yr (1874–2020). The were fitted power-law distribution four two-parameter (tapered-power-law, gamma, lognormal, Weibull distributi...

We consider cyclic Lotka-Volterra models with three and four strategies where at every interaction agents play a strategy using a time-dependent probability distribution. Agents learn from a loss by reducing the probability to play a losing strategy at the next interaction. For that, an agent is described as an urn containing β balls of three and four types, respectively, where after a loss one...

We calculate crossing probabilities and one-sided last exit time densities for a class of moving barriers on an interval [0, T ] via Schwartz distributions. We derive crossing probabilities and first hitting time densities for another class of barriers on [0, T ] by proving a Schwartz distribution version of the method of images. Analytic expressions for crossing probabilities and related densi...