2008
Autores
Bessa, R; Miranda, V; Gama, J;
Publicação
2008 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, VOLS 1-11
Abstract
This paper reports new results in adopting entropy concepts to the training of mappers such as neural networks to perform wind power prediction as a function of wind characteristics (mainly speed and direction) in wind parks connected to a power grid. It also addresses the differences relevant to power system operation between off-line and on-line training of neural networks. Real case examples are presented.
2009
Autores
Bessa, RJ; Miranda, V; Gama, J;
Publicação
IEEE TRANSACTIONS ON POWER SYSTEMS
Abstract
This paper reports new results in adopting entropy concepts to the training of neural networks to perform wind power prediction as a function of wind characteristics (speed and direction) in wind parks connected to a power grid. Renyi's entropy is combined with a Parzen windows estimation of the error pdf to form the basis of two criteria (minimum entropy and maximum correntropy) under which neural networks are trained. The results are favorably compared in online and offline training with the traditional minimum square error (MSE) criterion. Real case examples for two distinct wind parks are presented.
2012
Autores
Ferreira, CA; Gama, J; Costa, VS; Miranda, V; Botterud, A;
Publicação
Discovery Science - 15th International Conference, DS 2012, Lyon, France, October 29-31, 2012. Proceedings
Abstract
The motivation for this work is the study and prediction of wind ramp events occurring in a large-scale wind farm located in the US Midwest. In this paper we introduce the SHRED framework, a stream-based model that continuously learns a discrete HMM model from wind power and wind speed measurements. We use a supervised learning algorithm to learn HMM parameters from discretized data, where ramp events are HMM states and discretized wind speed data are HMM observations. The discretization of the historical data is obtained by running the SAX algorithm over the first order variations in the original signal. SHRED updates the HMM using the most recent historical data and includes a forgetting mechanism to model natural time dependence in wind patterns. To forecast ramp events we use recent wind speed forecasts and the Viterbi algorithm, that incrementally finds the most probable ramp event to occur. We compare SHRED framework against Persistence baseline in predicting ramp events occurring in short-time horizons, ranging from 30 minutes to 90 minutes. SHRED consistently exhibits more accurate and cost-effective results than the baseline. © 2012 Springer-Verlag Berlin Heidelberg.
2008
Autores
Bessa, R; Miranda, V; Gama, J;
Publicação
2008 10TH INTERNATIONAL CONFERENCE ON PROBABILISTIC METHODS APPLIED TO POWER SYSTEMS
Abstract
This paper reports new results in adopting entropy concepts to the training of mappers such as neural networks to perform wind power prediction as a function of wind characteristics (mainly speed and direction) in wind parks connected to a power grid. Renyi's Entropy is combined with a Parzen Windows estimation of the error pdf to form the basis of three criteria (MEE, MCC and MEEF) under which neural networks are trained. The results are favourably compared with the traditional minimum square error (MSE) criterion. Real case examples for two distinct wind parks are presented.
2023
Autores
Pashami, S; Nowaczyk, S; Fan, Y; Jakubowski, J; Paiva, N; Davari, N; Bobek, S; Jamshidi, S; Sarmadi, H; Alabdallah, A; Ribeiro, RP; Veloso, B; Mouchaweh, MS; Rajaoarisoa, LH; Nalepa, GJ; Gama, J;
Publicação
CoRR
Abstract
2023
Autores
Andrade, T; Gama, J;
Publicação
38TH ANNUAL ACM SYMPOSIUM ON APPLIED COMPUTING, SAC 2023
Abstract
Road transportation emissions have increased in the last few decades and have been the primary source of pollutants in urban areas with ever-growing populations. In this context, it is important to have effective measures to monitor road emissions in regions. Creating an emissions inventory over a region that can map road emissions based on vehicle trips can be helpful. In this work, we show that it is possible to use raw GPS data to estimate vehicle-related levels of pollution in a region. By transforming the data using feature engineering and calculating the vehicle-specific power (VSP) as well as various specific pollutants by using a microscopic emissions model, we show the areas with higher emissions levels made by a fleet of taxis in Porto, Portugal.
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