Network reconfiguration and loss allocation in a deregulated environment of distribution systems

Low flexibility and reliability in the operation of radial distribution networks make those systems be constructed with extra equipment as sectionalising switches in order to reconfigure the network, so the operation quality of the network can be improved. Thus, sectionalising switches are used for fault isolation and for configuration management (reconfiguration). Moreover, distribution systems are being impacted by the increasing insertion of distributed generators. Hence, distributed generation became one of the relevant parameters in the evaluation of systems reconfiguration. Distributed generation may affect distribution networks operation in various ways, causing noticeable impacts depending on its location. Thus, the loss allocation problem becomes more important considering the possibility of open access to the distribution networks. In this work, a graphic simulator for distribution networks with reconfiguration and loss allocation functions, is presented. Reconfiguration problem is solved through a heuristic methodology, using a robust power flow algorithm based on the current summation backward-forward technique, considering distributed generation. Four different loss allocation methods (Zbus, Direct Loss Coefficient, Substitution and Marginal Loss Coefficient) are implemented and compared. Results for a 32-bus medium voltage distribution network, are presented and discussed.

Urban sprawl and energy use for transportation in the largest Brazilian cities

A study of the relationships between the amount of energy consumed for transportation purposes and a few selected variables related to urban form and socioeconomic characteristics of some of the largest Brazilian cities is conducted in this work. The studied cities include all 27 state capitals regardless of their size and population and 184 urban areas each with more than 20,000 inhabitants located in the state of São Paulo. Two different techniques were applied for data analyses: a more traditional regression analysis approach and artificial neural networks. In general, the results found in the analyses conducted here support the assumption that urban sprawl increases the energy use for transportation. In the case of the 27 state capitals, the analysis indicated that two spatial variables have a strong impact on the energy consumed for urban transportation: urban density and the ratio between the longest distances in the east-west and north-south directions. In the case of the 184 urbanized areas we also reached a similar conclusion. In that case, however, income and employment level apparently have a stronger influence on the amount of energy consumed. The results of the present study stress the importance of physical planning in developing country cities in order to reduce energy use for transportation. © 2007 International Energy Initiative, Inc.

Wireless mesh networks planning based on parameters of quality of service

The use of QoS parameters to evaluate the quality of service in a mesh network is essential mainly when providing multimedia services. This paper proposes an algorithm for planning wireless mesh networks in order to satisfy some QoS parameters, given a set of test points (TPs) and potential access points (APs). Examples of QoS parameters include: probability of packet loss and mean delay in responding to a request. The proposed algorithm uses a Mathematical Programming model to determine an adequate topology for the network and Monte Carlo simulation to verify whether the QoS parameters are being satisfied. The results obtained show that the proposed algorithm is able to find satisfactory solutions.

Análise bibliométrica da revista Scire: Um estudo de colaboração científica institucional

The aim of this research is to make a bibliometric analysis of the journal Scire: Representación y Organización del Conocimiento, edited in Spain, in order to evidence the most productive institutions and countries, as well as to build a cooperation network and calculate the density indicators, centrality degree and betweenness. The 292 articles of the period 1996 to 2010 were analyzed. It was found out that, of the institutions participating in the articles, 25 institutions have been clearly the most productive. Almost all of them are Spanish, except four Brazilian ones and three more from three different countries. The institutional network showed a low density, but several cooperative sub-networks were identified, which suggest the existence of an international dialogue among researchers on the discipline.

A controvérsia nestoriana e suas implicações político-administrativas nas cartas de Cirilo de Alexandria (séc. V d.c.)

Pós-graduação em História - FCHS

Correspondence between the one-loop three-point vertex and the Y and Delta electric resistor networks

Different mathematical methods have been applied to obtain the analytic result for the massless triangle Feynman diagram yielding a sum of four linearly independent (LI) hypergeometric functions of two variables F-4. This result is not physically acceptable when it is embedded in higher loops, because all four hypergeometric functions in the triangle result have the same region of convergence and further integration means going outside those regions of convergence. We could go outside those regions by using the well-known analytic continuation formulas obeyed by the F-4, but there are at least two ways we can do this. Which is the correct one? Whichever continuation one uses, it reduces a number of F-4 from four to three. This reduction in the number of hypergeometric functions can be understood by taking into account the fundamental physical constraint imposed by the conservation of momenta flowing along the three legs of the diagram. With this, the number of overall LI functions that enter the most general solution must reduce accordingly. It remains to determine which set of three LI solutions needs to be taken. To determine the exact structure and content of the analytic solution for the three-point function that can be embedded in higher loops, we use the analogy that exists between Feynman diagrams and electric circuit networks, in which the electric current flowing in the network plays the role of the momentum flowing in the lines of a Feynman diagram. This analogy is employed to define exactly which three out of the four hypergeometric functions are relevant to the analytic solution for the Feynman diagram. The analogy is built based on the equivalence between electric resistance circuit networks of types Y and Delta in which flows a conserved current. The equivalence is established via the theorem of minimum energy dissipation within circuits having these structures.

O uso do rádio e da TV por instituições religiosas: um fenômeno crescente nos mais variados canais de comunicação

In the present study aimed to study the use of radio and television in Brazil by the various Christian aspects rooted in the country. The main objective was to analyze how the churches define the orientation or the use of strategies of both comprehensive and traditional media vehicles, which are still the most popular mass media, both for the formation of culture and national public opinion in both states and municipalities, which demarcate and retain regional traits that differentiate culturally, economically and socially diverse Brazilian populations. Christian churches are increasingly seeking loopholes and legal facilities, public spaces and broadcast media to facilitate the achievement of followers of their theological ideologies. On the radio, on television and also through social networks of the Internet, pastors, priests, bishops and lay Christians to seek their potential both in public space and home individually, using old and new individual devices and portable reception of audiovisual content. All preachers fiercely competing for space leased the open television networks, in national and local radio stations and invest in the organization of broadcasters Community legalized or informal. The work also aims to study the radio and television concessions in Bauru, to show the failures that occur in broadcasting spectrum management by the federal government and also for the reader to understand what the Constitution says about the use of these vehicles public concession by religious institutions

Cocriação nas redes sociais: um estudo do caso Jornada Ekos

This study aims to address the significance of co-creation and its importance in the process for competitive advantage among the processes and social changes that have impact on the interests and market needs. For this, was made a case study of the project Jornada Ekos, of Natura, an open network of people who identify with the essence and purpose of the company, through a literature search in the works and records of the Jornada Ekos, such as sites about the study, social networks and search of testimonials. Was analyzed the strategies of the co-creation process used by the company on social networks in 2014. The elements analyzed were content, content generation, multimedia content, multiple platforms, interaction, building bond and innovation. The analysis identified a communication which sought to build strong bonds with those involved on the Jornada Ekos, once the company sought to innovate through co-creation and strengthen the relationship with the public, in addition to strengthening the institutional image of the organization through the dissemination of Jornadas Ekos project on the media

O papel das redes de transformação no processo de inovação: estudos de caso sobre a descoberta e a comercialização da inovação

Innovation is widely recognized as important. In addition, in this context, innovation networks have gained importance in academic studies, since an organization alone, does not always have access to all necessary resources. Gobbo Junior and Olsson (2010) proposed a model of network innovation whereby the transformation networks would be the linking structures between exploration and exploitation networks. In this context, this paper presents two case studies of innovation networks, aiming to increase the understanding on transformation networks. The objective was to understand how they interconnect exploration and exploitation networks; the main actors present in this interface; and to evaluate whether these actors can act as agents, to accelerate the innovation process. It was possible to verify how the transformation networks interconnect exploration and exploitation, and identify the practices and their main actors.

Neural models for predicting hole diameters in drilling processes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Neural models for predicting hole diameters in drilling processes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)