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The wide spread use of power electronic equipment causes serious current harmonics in electrical power system. Harmonic currents that flow in the electrical power system would cause extra copper loss and immature operation of over current protection devices. Voltage distortion due to harmonic voltage drop in the electrical power distribution system impairs the operation of voltage-sensitive equipment. To improve the electrical power quality and reduce energy wastage in the electrical power distribution system, especially under the deregulated environment, the nature of the harmonics must be identified so that the causes and effects of the harmonics would be studied. Moreover, corrective measures cannot be easily implemented without knowing the characteristics of the harmonics existing in the electrical power system. The chapter presents investigation results obtained from the harmonics analysis and modeling of load forecast and consists of three main sections. The first presents an algorithm based on continuous wavelet transform (CWT) to identify harmonics in a power signal. The new algorithm is able to identify the frequencies, amplitudes, and phase information of all distortion harmonic components, including integer harmonics, sub-harmonics, and inter-harmonics. The second section describes a wavelet transform-based algorithm for reconstructing the harmonic waveforms from the complex CWT coefficients. This is useful for identifying the amplitude variations of the nonstationary harmonics over the estimation period. The third section presents wavelet-genetic algorithm-neural network-based hybrid model for accurate prediction of short-term load forecast. Examples and case study will be used to demonstrate the benefits derived from these approaches. [ABSTRACT FROM AUTHOR]

Defining a procedure to calculate the H/V spectral ratio of seismic noise has recently been the focus of several studies. Although some issues have been addressed and a general procedure to follow in choosing the optimal seismological equipment, carrying out the measurements and analyzing the data has been agreed upon by the majority of specialists in this field, some points still remain open. One open question is whether transients should be avoided when H/V spectral ratios are calculated. Starting from contradictory results of previous papers, an ad-hoc experiment at the Nauen test site (Germany) was conducted to verify the influence of transients on the H/V spectral ratio of seismic noise. We show, consistent with some previous studies, that transients generated by high frequency content sources can amplify spectral ratio peaks at low frequencies. After careful polarization analysis of the data and estimation of the spectral amplitude decay with distance, we provide an explanation in terms of the composition of the wavefield over certain distance ranges. Our results highlight the importance of a better understanding of the wave-field composition for better exploiting the potential of H/V spectral ratio method. [ABSTRACT FROM AUTHOR]

In this paper a novel model for transients detection in piecewise stationary signals is presented. A hybrid representation is assumed for the signal and the different behavior of each component (stationary, transient and stochastic) in the time-scale plane is exploited. Experimental results on both shape contours, described by a differential chain code, and audio signals show the generality of the proposed model. [ABSTRACT FROM AUTHOR]

Since the publication of Rolando Mellafe's groundbreaking study on the importance of migration in the Viceroyalty of Peru, demographers have emphasized the significance of the city as a factor in colonial Latin American migration patterns. The city has figured prominently in various efforts to characterize general population trends and migrants have been important subgroups in analyses of the censuses of specific cities. Rather than emphasizing the role of the city in migration patterns, this study attempts to address the role of the migrant within the colonial city by utilizing a different data source: the conciertos de trabajo, or labor contracts, governing indigenous workers in seventeenth-century Cuzco. These conciertos yield a variety of data on job descriptions and distributions, periodic crises in the labor market, regional economic patterns, changing family relationships, and growing occupational identification. The detailed information from these valuable notarial documents adds a new and important dimension to the analysis of indigenous migration in colonial Peru. Although this study emphasizes migrations to the city of Cuzco, such migration did not take place in a vacuum. The city was also an important source for an urban-to-rural population outflow, as urban natives moved into depopulated lands in the countryside. Moreover, broader patterns of indigenous migration affected the provinces surrounding Cuzco. Migration within the bishopric of Cuzco varied dramatically according to regional labor trends and mita obligations, but much of that population movement involved short-scale relocation by individuals who remained within rural society. These various interrelated patterns of migration had a profound impact on the indigenous communities and played a major role in the formation of colonial society. [ABSTRACT FROM AUTHOR]