By endowing his agents with simple forecasting models, or representations, Woodford (1990) found that finite state Markov sunspot equilibria may be stable under learning. We show that common factor representations generalize to all sunspot equilibria the representations used by Woodford (1990). We find that if finite state Markov sunspots are stable under learning then all sunspots are stable u...

We consider a linear univariate rational expectations model, with a predetermined variable, and study existence and stability of solutions driven by an extraneous finite-state Markov process. We show that when the model is indeterminate there exists a new class of kstate dependent sunspot equilibria in addition to the k-state sunspot equilibria (k-SSEs) already known to exist in part of the ind...

ABSTRACT The Carte Synoptique catalogue of solar filaments from March 1919 to December 1989, corresponding to complete cycles 16 to 21 is utilized to show latitudinal migration of filaments at low latitudes ( less than 50), and the latitudinal drift of solar filaments in each hemisphere in each cycle of the time interval is compared with the corresponding drift of sunspot groups. The latitudina...

The dates of presentation of 191 cases of acute closed-angle glaucoma which presented at the Birmingham and Midland Eye Hospital between 1971 and 1974 were analysed and the seasonal incidence of acute glaucoma confirmed (P<0.001). These data were compared with meteorological data for air temperature, rainfall, hours of sunshine, atmospheric pressure, cloud amount, terrestrial magnetic field lev...

A hybrid system for the automated detection and McIntosh-based classification of sunspot groups on SOHO/MDI white-light images using active-region data extracted from SOHO/MDI magnetogram images is presented in this paper. After sunspots are detected from MDI white-light images they are grouped/clustered using MDI magnetogram images. By integrating image-processing and Neural Networks technique...

■ Abstract Important physical processes on the Sun, and especially in sunspots, occur on spatial scales at or below the limiting resolution of current solar telescopes. Over the past decade, using a number of new techniques, high-resolution observations have begun to reveal the complex thermal and magnetic structure of a sunspot, along with associated flows and oscillations. During this time re...

Sunspot equilibrium and lottery equilibrium are two stochastic solution concepts for nonstochastic economies. Recent work on nonconvex exchange economies has shown that when the randomizing device is a continuous random variable, applying the two concepts to the same fundamental economy yields the same set of equilibrium allocations. In the present paper, we examine economies based on a discret...

Sunspots are the subject of interest to many astronomers and solar physicists. Sunspot observation, analysis and classification form an important part of furthering the knowledge about the Sun. Sunspot classification is a manual and thus very labor intensive process that could be automated if it can be successfully learned by a machine. This paper deals with data mining approaches to the proble...

In this study, the relationship between annual sunspot number (ASN) and annual precipitation totals (APT) has been investigated over the northern coasts of the Persian Gulf and Oman Sea by using two statistical methods: contingency tables and cross-correlation function. Only Bushehr and Jask stations (270 mm and 140 mm mean APT) have long term monthly precipitation records started instrumentall...

In order to improve the forecasts of the impact of solar activity on the terrestrial environment on time scales longer than days, improved understanding and forecasts of the solar activity are needed. The first results of a new approach of modelling and forecasting solar activity are presented. Time series of solar activity indicators, such as sunspot number, group sunspot number, F10.7, E10.7,...