The use of static frequency converters, which have a high switching frequency, generates voltage pulses with a high rate of change over time. In combination with cable and motor impedance, this generates repetitive overvoltage at the motor terminals, influencing the occurrence of partial discharges between conductors, causing degradation of the insulation of electric motors. Understanding the effects resulting from the frequency converter–electric motor interaction is essential for developing and implementing insulation systems with characteristics that support the most diverse applications, have an operating life under economically viable conditions, and promote energy efficiency. With this objective, a search was carried out in three recognized databases. Duplicate articles were eliminated, resulting in 1069 articles, which were systematically categorized and reviewed, resulting in 481 articles discussing the causes of degradation in the insulation of electric motors powered by frequency converters. A bibliographic portfolio was built and evaluated, with 230 articles that present results on the factors that can be used in estimating the life span of electric motor insulation. In this structure, the historical evolution of the collected information, the authors who conducted the most research on the theme, and the relevance of the knowledge presented in the works were considered.

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Territorial planning plays a fundamental role in preservation of areas for ecological conservation and environmental management as well as in providing adequate spaces for visitation and research and prioritizing sustainable relationships between man and nature. The present work exhibits a methodological proposal that allows the standardization of territorial classifications in preservation areas. Based on fuzzy logic, the proposed model observes the particularities of a preservation area; hence, the decision generated in the classification of zones represents the work that is currently being developed in the areas of biology, geography, environmental engineering, among other research groups. The modeling combines the evaluation of the data collected in the field (variables: quantitative and qualitative) with vegetation indices obtained from satellite imagery. Combining this information enables each sampling point to be categorized, thereby generating preservation area zones. The results showed that the methodology can distinguish border areas as transition zones, allowing appropriate management to offer detailed information of the study area. The case study, in which the methodology was applied in a preservation area in southern Brazil, showed that the methodology assists in territorial planning, with a clear indication of what actions have been performed and simple data collection.

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The aim of this paper is to evaluate the efficiency and productivity change of Paraná’s Credit Union. The analysis considered 45 units (each credit union researched), each of one with 10 variables in each period (8 inputs and 2 outputs). This evaluation has taken into account quarterly credit union’s data, from January 2009 to July 2015 (27 periods). The methodology included Data Envelopment Analysis (DEA), Principal Components Analysis (PCA) and Malmquist Index (MI) techniques. The results showed that DMUs 453, 498 and 517 were considered 100% efficient in all periods, making them ideal benchmarks. There was no case that a DMU was not considered 100% efficient in at least one observation. The MI showed that the difference between the biggest and the smallest average was significant (varying between 19.837 for DMU 251 and 0.926 for DMU 450). The average between all MI was 4,735 with a standard deviation of 3,547, evidencing the different measures of efficiency between each DMU when compared to the others.

The objective of this study was to verify the impact of convergence Brazilian accounting standards international accounting systems performance assessment of the economic and financial sector companies listed on the construction and transportation BM&FBovespa. Was used the model of data envelopment analysis (DEA) to evaluate financial performance. The data refer to the re-release of 55 companies in the construction and transportation in 2009, using a set of 23 indicators. The DEA model used in the evaluation of the economic and financial performance was satisfactory and earned important results for the comparison between before and after IFRS. The results were significant in the comparison between the results in IFRS and BR GAAP, which indicates and effectives the relationship between the two performances of companies. Thus we conclude that the performance was not affected with the change of accounting standards in Brazil.

Radiotherapy planning is vital for ensuring the maximum level of effectiveness of treatment. In the planning task, there are at least two connected decision problems that can be modelled and solved using operational research techniques: determining the best position of the radiotherapy machine (beam angle problem) and the optimal dose delivered through each beam (dose distribution problem). This paper presents a mathematical optimization model for solving the combined beam angle and dose distribution problems in the presence of multiple objectives. A matheuristic based on Tabu Search (called TSrad) is developed to solve realistic large-scale instances. The performance of the proposed method is assessed on two prostate cancer instances, namely a single computed tomography (CT) slice and a set of CT slices (three-dimensional problem). For the single-slice problem, the results of TSrad are compared to the optimal solutions obtained by an exact method. Our experiments show that TSrad is able to achieve optimality for some instances. For the multi-slice problem, our experiments show that TSrad produces viable solutions that can be attained in a reasonable computational time.

In this paper we propose a new algorithm for finding a feasible initial solution to transportation problems. The MOMC Method (Maximum Supply with Minimum Cost) as it was called, was compared with three classical methods: Corner Northwest, Minimum Cost and Vogel, obtaining significant results (better than the methods shown). A numerical example was presented to a rigorous understanding of the algorithm, and the results in a case study with a transportation problem with fuzzy parameters after the application of a classification technique showed great computational advantage (higher processing speed and less use of memory).