4 resultados para Fourier and Laplace Transforms

em Universidade Federal do Rio Grande do Norte(UFRN)


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This work an algorithm for fault location is proposed. It contains the following functions: fault detection, fault classification and fault location. Mathematical Morphology is used to process currents obtained in the monitored terminals. Unlike Fourier and Wavelet transforms that are usually applied to fault location, the Mathematical Morphology is a non-linear operation that uses only basic operation (sum, subtraction, maximum and minimum). Thus, Mathematical Morphology is computationally very efficient. For detection and classification functions, the Morphological Wavelet was used. On fault location module the Multiresolution Morphological Gradient was used to detect the traveling waves and their polarities. Hence, recorded the arrival in the two first traveling waves incident at the measured terminal and knowing the velocity of propagation, pinpoint the fault location can be estimated. The algorithm was applied in a 440 kV power transmission system, simulated on ATP. Several fault conditions where studied and the following parameters were evaluated: fault location, fault type, fault resistance, fault inception angle, noise level and sampling rate. The results show that the application of Mathematical Morphology in faults location is very promising

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The great amount of data generated as the result of the automation and process supervision in industry implies in two problems: a big demand of storage in discs and the difficulty in streaming this data through a telecommunications link. The lossy data compression algorithms were born in the 90’s with the goal of solving these problems and, by consequence, industries started to use those algorithms in industrial supervision systems to compress data in real time. These algorithms were projected to eliminate redundant and undesired information in a efficient and simple way. However, those algorithms parameters must be set for each process variable, becoming impracticable to configure this parameters for each variable in case of systems that monitor thousands of them. In that context, this paper propose the algorithm Adaptive Swinging Door Trending that consists in a adaptation of the Swinging Door Trending, as this main parameters are adjusted dynamically by the analysis of the signal tendencies in real time. It’s also proposed a comparative analysis of performance in lossy data compression algorithms applied on time series process variables and dynamometer cards. The algorithms used to compare were the piecewise linear and the transforms.

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During the latest years, the art of storytelling has received special attention from those who make education, art and culture. The storyteller is a singular person who manages to seduce itself and its listeners, by involving them in an atmosphere of pleasure and complicity, dodging situations, space and time, providing delight, stimulating creativity, daydreaming and imagination. This is a study developed with storyteller teachers that takes as its starting point the need to change the landscape of education, which seeks to emphasize the affirmation of embodiment of the teacher, so that it participates in a creative self-dynamic and the context in which they live. In addition , the following purposes accompanied the study : education - liberating practice and human development ; corporality - radiant , first and main focus of educational criteria; playfulness - a human dimension ; autopoiese - as an organization of human beings that produces and continuously transforms itself; flow experience concerns the feeling of full involvement in the activity , the psychic energy toward something that is being produced or performed , something that brings us pleasure , happiness and profound sense of well being. As general objective of the study we analysed the humanescent self-formation and its ludopoiética nature in storyteller teachers from humanescent workshops developed in a state school in Natal / RN. In view of the overall objective , we developed the following specific objectives : to identify the ludopoiéticas properties of self-worth , self-connectivity , self-territoriality , autotelia and self realization present in the life of storyteller teachers and the changes in the school environment, from the development of humanescent workshops; reveal the nature of humanescent self-training in storyteller teachers lives. The investigated group had the participation of eight teachers, and had the Escola Estadual Potiguassu as environment for the research. This is a descriptive study, understood as an action-research , developed with basis in the fundamentals and ethnomethodological principles , which used eight humanescents workshops , developed in the context of humanescent experiential pedagogy in conjunction with participant observation .The analyzes were focused on the chosen categories for the study : self-worth , self-connectivity , self-territoriality , autotelia and self-, indexicality and reflexivity . In terms of conclusions, we noted that the properties of ludopoiese were unveiled in the lives of the teachers by providing changes in their ways of being and living together. The teachers have become more creative and intensely began to experience their own life, social life, as well as its meaning. The struggle for a more cheerful and happy school was another important development highlighted in the reports of the teachers, also observing that there was a significant improvement in the reduction of violence in the school environment. Thus, we emphasize that the teachers began to recognize themselves like being ludic, playing with the beauty of storytelling and life

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In this work we use Interval Mathematics to establish interval counterparts for the main tools used in digital signal processing. More specifically, the approach developed here is oriented to signals, systems, sampling, quantization, coding and Fourier transforms. A detailed study for some interval arithmetics which handle with complex numbers is provided; they are: complex interval arithmetic (or rectangular), circular complex arithmetic, and interval arithmetic for polar sectors. This lead us to investigate some properties that are relevant for the development of a theory of interval digital signal processing. It is shown that the sets IR and R(C) endowed with any correct arithmetic is not an algebraic field, meaning that those sets do not behave like real and complex numbers. An alternative to the notion of interval complex width is also provided and the Kulisch- Miranker order is used in order to write complex numbers in the interval form enabling operations on endpoints. The use of interval signals and systems is possible thanks to the representation of complex values into floating point systems. That is, if a number x 2 R is not representable in a floating point system F then it is mapped to an interval [x;x], such that x is the largest number in F which is smaller than x and x is the smallest one in F which is greater than x. This interval representation is the starting point for definitions like interval signals and systems which take real or complex values. It provides the extension for notions like: causality, stability, time invariance, homogeneity, additivity and linearity to interval systems. The process of quantization is extended to its interval counterpart. Thereafter the interval versions for: quantization levels, quantization error and encoded signal are provided. It is shown that the interval levels of quantization represent complex quantization levels and the classical quantization error ranges over the interval quantization error. An estimation for the interval quantization error and an interval version for Z-transform (and hence Fourier transform) is provided. Finally, the results of an Matlab implementation is given