Signal-flow graphs: Direct method of reduction and MATLAB implementation

Block diagrams and signal-flow graphs are used to represent and to obtain the transfer function of interconnected systems. The reduction of signal-flow graphs is considered simpler than the reduction of block diagrams for systems with complex interrelationships. Signal-flow graphs reduction can be made without graphic manipulations of diagrams, and it is attractive for a computational implementation. In this paper the authors propose a computational method for direct reduction of signal-flow graphs. This method uses results presented in this paper about the calculation of literal determinants without symbolic mathematics tools. The Cramer's rule is applied for the solution of a set of linear equations, A program in MATLAB language for reduction of signal-flow graphs with the proposed method is presented.

On lag controllers: Design and implementation

Sometimes it is inconvenient or expensive to open the loop of a system to insert lag controllers-for instance, when this system is an open-loop system. A new controller structure where the loop is not opened, and that allows the design of lag controllers as in the case where one can open the loop, is presented. This result can be used by educators in undergraduate courses that deal with classic control system theory, because it allows a better comprehension of the concept of lag compensation and provides a new method for its design and implementation. An example illustrates the application of the proposed method.

DIRECT EXPRESSIONS FOR OGATA LEAD-LAG DESIGN METHOD USING ROOT LOCUS

Direct expressions for the design of a lead-lag continuous compensator using the root locus method and the procedure described in the 1970 and 1990 books by Ogata are presented. These results are useful in the Ogata design method because they avoid the geometrical determination of poles and zeros, making it easier to create a computer-based design.

Anísio Teixeira e a Psicologia: o valor da mensuração

This article analyzes the ideas and the work of Anísio Teixeira in the 1920s and 1930s, focusing on his views about the value of measurement for educational reform in Brazil. Considering that the thinking and practices of Teixeira should be understood in the context in which it was developed, the study presents the history of the presence of psychological knowledge in education, with special attention to the entrance of the Psychometrics in the New School movement. The paper concludes that, by defending the use of measurement, Teixeira has remained true to the goal of the New School that required to diagnoses scientifically the school universe, which was necessary to respond to the growing demand for schooling and the educational disabilities of the Brazilian educational institutions.

Estudo das representações do mundo do trabalho de alunos do meio rural através do uso de mídias virtuais

This paper aims to present the representations of the working world of high school students, the State School Prof. Dr. João Deoclécio da Silva Ramos, Distrito de Talhado, São José do Rio Preto (SP), through the use of virtual media, specifically the Blog de Aula – Mutirão de Sociologia (www.mutiraodesociologia.com.br). Understanding the representations of the world work enables students to think of a profession which identify themselves, and stimulate reflection as future professionals. The virtual media, especially blogs, allow students to express their ways of living and thinking the world of work. In the context of the city of Rio Preto, is especially relevant these representations of the world’s rural work, so this project is to collaborate in the development of research concerned with the description and understanding of processes that involve relationships between work, education and rural.

Concepções políticas e educacionais de Renato Jardim na década de 1930

This article aims to analyze the political and educational conceptions of Renato Jardim, intellectual who participated actively in Brazilian educational and political scenario in the early decades of XXth century. He was responsible for educational reform initiatives and had an active participation in major debates on education that occurred at that time. The methodology is the traditional analyses of bibliography. In addition to literature specialized in this theme, this work uses the author’s autobiography published in 1946 and four books of his own published between 1932 and 1936. In political area, it examines his arguments concerning the government stated by Getúlio Vargas in 1930 and the constitutionalist movement of 1932. In educational area, the work analyses his ideas regarding the introduction of psychoanalysis in pedagogical practices and his thoughts in search of a definition for the concept of New School.

O discurso de Lourenço Filho em defesa da pedagogia do estado novo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anísio Teixeira e a psicologia: o diálogo com a psicanálise

This paper analyses the ideas and the work of Anísio Teixeira in the first years of the 1930s, focusing his conceptions concerning the value of Psychoanalysis for Educational Reform in Brazil. Whereas the ideas and practices Teixeira should be understood in the historical context in which they were developed, the work presents the history of the introduction of the psychoanalytic knowledge in the Brazilian Renovator Educational Movement, highlighting the relevance of hygienism in the dissemination of Freud's theses in education. The findings indicate that Teixeira interacted with the concepts of Psychoanalysis through the hygienist movement and the ideas of Arthur Ramos, considering the individual as being linked to the social environment.

Intelectuais brasileiros em disputa pela Escola Nova na década de 1930

In the first decades of the last century, Brazilian intellectuals played an im- portant role in the new configuration to the country reached. Brazil had then passed by rapid process of moderniza- tion. The educational field was place of contention between different currents of intellectuals. The idea was to create a new society through what is called the New School. In Brazil, unlike in Europe, most of the population had no access to school. Therefore, the New School was not privileged to critique existing school system, but the actual construction of the large Brazilian childhood schooling. Thus, we crea- ted libraries in teaching urban school groups, with the aim of improving the training of primary school teachers in the pedagogical ideas of the New School. This work has for objective to understand the conflicts among Brazi- lian intellectuals on the list of recommended readings for teacher training schools in the first half of the twentieth century. This paper presents an exam- ple of this intellectual dispute through the analysis of a Brazilian school li- brary copy of the 1930s.