15,935 research outputs found
Optimized complex power quality classifier using one vs. rest support vector machine
Nowadays, power quality issues are becoming a significant research topic because of the increasing inclusion of very sensitive devices and considerable renewable energy sources. In general, most of the previous power quality classification techniques focused on single power quality events and did not include an optimal feature selection process. This paper presents a classification system that employs Wavelet Transform and the RMS profile to extract the main features of the measured waveforms containing either single or complex disturbances. A data mining process is designed to select the optimal set of features that better describes each disturbance present in the waveform. Support Vector Machine binary classifiers organized in a ?One Vs Rest? architecture are individually optimized to classify single and complex disturbances. The parameters that rule the performance of each binary classifier are also individually adjusted using a grid search algorithm that helps them achieve optimal performance. This specialized process significantly improves the total classification accuracy. Several single and complex disturbances were simulated in order to train and test the algorithm. The results show that the classifier is capable of identifying >99% of single disturbances and >97% of complex disturbances.Fil: de Yong, David Marcelo. Universidad Nacional de RÃo Cuarto. Facultad de IngenierÃa. Departamento de Electricidad y Electrónica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba; ArgentinaFil: Bhowmik, Sudipto. Nexant Inc; Estados UnidosFil: Magnago, Fernando. Universidad Nacional de RÃo Cuarto. Facultad de IngenierÃa. Departamento de Electricidad y Electrónica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba; Argentin
The limit of massive gravity
Lorentz-invariant massive gravity is usually associated with a strong
coupling scale . By including non-trivial effects from the
Stueckelberg modes, we show that about these vacua, one can push the strong
coupling scale to higher values and evade the linear vDVZ-discontinuity. For
generic parameters of the theory and generic vacua for the Stueckelberg fields,
the -decoupling limit of the theory is well-behaved and free of any
ghost or gradient-like instabilities. We also discuss the implications for
nonlinear sigma models with Lorentzian target spaces.Comment: 38 pages, 1 figure, JHEP version, minor change
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