The combination of neural estimates in prediction and decision problems

In this dissertation, different ways of combining neural predictive models or neural-based forecasts are discussed. The proposed approaches consider mostly Gaussian radial basis function networks, which can be efficiently identified and estimated through recursive/adaptive methods. Two different ways of combining are explored to get a final estimate – model mixing and model synthesis –, with the aim of obtaining improvements both in terms of efficiency and effectiveness. In the context of model mixing, the usual framework for linearly combining estimates from different models is extended, to deal with the case where the forecast errors from those models are correlated. In the context of model synthesis, and to address the problems raised by heavily nonstationary time series, we propose hybrid dynamic models for more advanced time series forecasting, composed of a dynamic trend regressive model (or, even, a dynamic harmonic regressive model), and a Gaussian radial basis function network. Additionally, using the model mixing procedure, two approaches for decision-making from forecasting models are discussed and compared: either inferring decisions from combined predictive estimates, or combining prescriptive solutions derived from different forecasting models. Finally, the application of some of the models and methods proposed previously is illustrated with two case studies, based on time series from finance and from tourism.

What public experience may be - on publicity, communication and the expression of lived experiences

The idea of public experience is often invoked in different social and academic contexts. However, it seldom deserved a reflection that specifically sought to deepen its meaning from the point of view of social life. In this article we contribute to the understanding of the uniqueness of the public form of experience. We believe that one of the best ways through which we can observe the public experience is by the objectification, performance and dramatization of the culture, i.e., the “expression of lived experiences”. There is, in publicity, the possibility of simultaneous allocation of individual and collective experiences, and it is in this sense that we can see how culture influences the shaping of experience itself. Public experience is characterized by the weaving and intertwining of singular experiences that are pluralized and plural lived experiences that are singularized, in a process where individual and society interpenetrate. The relationship between experience and publicity arises from this symbolic communion contained in the systems of thought and action of societies. The decisive role of the principle of publicity to experience consists, according with the hypothesis we wish to put forward, in making available and communicating the social world of symbolic (cultural) activity. Public experience is, then, envisaged as the experience of a common world where both singular and plural definitions of the individual (taken as society) converge through lived experiences and, particularly, through their expression, which can take different symbolic forms.