Transformada wavelet aplicada a análise automática de oscilografias de curta duração em unidades geradoras

The focus of this work is the automatic analysis of disturbance records for electrical power generating units. The main proposition is a method based on wavelet transform applied to short-term disturbance records (waveform records). The goal of the method is to detect the time instants of recorded disturbances and extract meaningful information that characterize the faults. The result is a set of representative information of the monitored signals in power generators. This information can be further classified by an expert system (or other classification method) in order to classify the faults and other abnormal operating conditions. The large amount of data produced by digital fault recorders during faults justify the research of methods to assist the analysts in their task of analysing the disturbances. The literature review pointed out the state of the art and possible applications for oscillography records. The review of the COMTRADE standard and wavelet transform underlines the choice of the method for solving the problem. The conducted tests lead to the determination of the best mother wavelet for the segmentation process. The application of the proposed method to five case studies with real oscillographic records confirmed the accuracy and efficiency of the proposed scheme. With this research, the post-operation analysis of occurrences is improved and as a direct result is the reduction of the time that generators are offline.

A narrativa histórica de Alexandre Wollner sobre o design brasileiro em sua relação com arte, indústria e tecnologia

This work aims to investigate the historical narratives in which the graphic designer Alexandre Wollner assembled about the development of its own profession in Brazil, focusing the ways in which his discourse points relations among design (with greater emphasis in graphic design) and visual arts, the industrial development and notions about technology. Firstly, the theoretical setup searched for dialogues with design historians, with Mikhail Bakhtin, specially his concepts about “ideology” and “discourse’, and the theory of Field Autonomy by Pierre Bourdieu applied in the artistic practice. Following, the relation between Wollner’s own journey and the Brazilian industrial development is shown, and, at last, three of his historical texts are studied, which are written in different moments (1964; 1983; 1998), being those in which the analyzed author wished to point out the origens, events and names that are more remarkable. Throughout the work, it is pointed the importance of Wollner’s contact with the modernist european ideologies that share an abstract and rationalist matrix found at Hochschule für Gestaltung Ulm (HfG Ulm), the german design school from the city of Ulm, in the 1950s. Such modernist discourse understood the practice of design as a method with scientific character, being then different of some other more recurring artistic professional practices in some productive sectors. Wollner aimed to apply such ideals in his professional practice, being the foundation of the paulista office forminform, in 1958, one of his first expressions of such posture, and in his academic practice, helping the foundation of the Escola Superior de Desenho Industrial (ESDI), in Rio de Janeiro, in 1963. Such modernist ideals went along with moments of the Brazilian industrial development during the government of Juscelino Kubitschek (1956–1961) and the “Economical Miracle” from the military government (1968–1973). Wollner argued about the need for the development of national design as a technological and productive differential that would help the growth of national industry, based on Ulm’s project model concept. It is defended that Wollner’s professional and intelectual path, in his efforts of thinking a history of Brazilian design through the choice of pioneers in the area, was founded on an “ideal model” of design, leaving aside the modernist experiences from the 1950s. Such posture would indicate a search for validation of his own profession that was beginning to become more evident in Brazilian productive means, aiming the creation of a differential space in comparison with pre-established practices, usually link to graphic artists from the time.