Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Model combination in neural-based forecastingPublication . Freitas, Paulo S. A.; Rodrigues, António J. L.This paper discusses different ways of combining neural predictive models or neural-based forecasts. The proposed approaches consider Gaussian radial basis function networks, which can be efficiently identified and estimated through recursive/adaptive methods. The usual framework for linearly combining estimates from different models is extended, to cope with the case where the forecasting errors from those models are correlated. A prefiltering methodology is pro posed, addressing the problems raised by heavily nonstationary time series. Moreover, the paper discusses two approaches for decision-making from forecasting models: either inferring decisions from combined predictive estimates, or combining prescriptive solutions derived from different forecasting models.
- Experiments in machine learning of alpha-decay half-livesPublication . Freitas, Paulo S. A.; Clark, John W.Artificial neural networks are trained by a standard backpropagation learning algorithm with regularization to model and predict the systematics of alpha decay of heavy and superheavy nuclei. This approach to regression is implemented in two alternative modes: (i) construction of a statistical global model based solely on available experimental data for alpha-decay half-lives and Q-values, and (ii) modeling of the residuals between the predictions of state-of-the-art phenomenological model (specifically, the effective liquid-drop model (ELDM)) and experiment. Analysis of the results provides insights on the strengths and limitations of this application of machine learning (ML) to exploration of the nuclear landscape in regions beyond the valley of stability.