RCAAP Repository

Nowadays, researches and developments related to Power Quality subject have motivated a great afford of work in many centers involved with studies on electrical engineering. Amongst the areas of interest, emerge the investigations associated to the operation of large, medium and small electric-electronic devices. These are frequently found in industrial, commercial and residential installations. Added to the questions of performance analysis of these products, the degree of equipment sensitivity, supportability and withstand capabilities are becoming major concerns in this context. These worries are quite relevant so as to define the equipment/process dependence with the supply conditions as well as the definition of compensation solutions such as consumers refunding. Recognizing, therefore, the importance of these facts, this work is devoted to obtaining the allowable limits of voltage and current of a stereo. A proposed methodology and structure for laboratory destructive testing is presented involving tests at power frequency, simulation of falling out of the high voltage in the low voltage cables and impulsive transients that guided the development of the of thermal and dielectric withstand capability curves of the equipment under investigation. Based on the results obtained, some real cases of compensation claims along with an electric utility are presented and simulated in computer application APR. In addition, further studies are carried out to evaluate the influence of mitigating devices in analysis techniques and their impact on emission of reports for electrical damages claim.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

IEEE 802.16j networks provide, through the Relay Station (RS), improvements with regard to previous specifications of WiMAX in terms of increased coverage area, reduction of deployment costs due to low cost of RS compared to a Base Station (BS) and system average throughput increase. Its main purpose is to meet demands for wireless broadband access at lower cost. The efficient resource allocation is a challenge in the IEEE 802.16 standard and requires total commitment of scheduling algorithm. Few proposals for downlink scheduling developed for IEEE 802.16j networks are relevant to the present moment, and much of it disregards the maximum utilization of basic resources available, such as using only one RS due to a large traffic load, for example. In view of this, we propose the application of a Deficit Round Robin (DRR) algorithm with adaptive quantum operating together with a queue management and congestion control in RS. In the proposed DRR scheduling, implemented in the BS downlink scheduler, the quantum is calculated using the Maximum Transmission Unit (MTU) size and information about the congestion state in RS. In order to balance the average queue length in the output buffer of RS, we have implemented an algorithm based on Adaptive Random Early Detection (ARED). Finally, the proposed solution was evaluated using modeling and simulation. The simulation results demonstrate good performance of the proposed classes for UGS, rtPS, nrtPS and BE compared to a conventional DRR scheduling without queue management.

The Virtual Reality (VR) mainly deals with the creation of three-dimensional environments generated in real time and made available for multisensory interaction with different devices. A high processing capacity and modeling environments is required for applications of this nature. These applications currently extend to various productive sectors such as industry, medicine and health, training (capacity building) and, in particular, in the Education. There are several areas of knowledge that explore VR as a teaching tool to complement the techniques applied to the binomial teaching / learning in a pedagogical context. In recent years, various issues related to the teaching of Mathematics has been a subject of interest and research into the use of Virtual Reality techniques. The developed systems have proved a increase advanced in the use of this technology. One area of the interest for mathematics industry is the study of surfaces NURBS (nonuniform Rational B-Spline). These surfaces have application in many areas of industry and engineer - such as design of automobiles, aircraft, shoes, bottles etc. However, reseachers computer systems were developed as a proposed tool for study and manipulation of NURBS with small levels of interaction and created models. These itens associated with the navigation and involvement, implicit concepts to worked by RV, certainly provide a more natural and user-friendly system. Therefore, this research has come up with a proposal to investigate how VR techniques can be used for teaching and even training in the area of NURBS. Thus, a computer system was developed and evaluated with potential users. The evaluated results demonstrate that virtual reality techniques offer an interesting field of research to provide some computational methods, that lead more dynamic and motivational to study NURBS.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

This dissertation aims at analysing how metallurgy workers in São José dos Campos perceived and, through their experiences, interpreted changes happening in the city (along with urbanization process) as well as in their work (along with industrialization and production restructure process) from the seventies until today. By connecting to oral narratives of metallurgy workers who lived end live this process, we understand how they interpret changes to their way of life and work in the city. This dissertation also analyses written sources like São José dos Campos local press news and metallurgy syndicate s newspaper, O Metalúrgico , mainly in the Dito Bronca section, a space where workers send their complaints and denunciation about daily life facts. Although most of their complaints are about what goes inside the workplace in the industry, denunciation about their immediate chiefs, there is evidence about the living dimension of these metallurgy workers out of their workplace as the problem of working far from home and the worker s disputes for leasure. I looked forward to facing these workers actions in the working place, as well as their home place, in the suburbs. This leads to the analysis of their living habits, of which not only strikes and manifestations are evident, but also their fight for improvements in the quarter, leasure, expectations, rhythm of work, feeding, among others. This dissertation is organized in three chapters: Chapter I: Follows the life and work paths of these metallurgy workers connecting them to the urbanization process of their city, São José dos Campos; Chapter II: Analyses the transformation process of the work in the industry, referenced by the experiences of theses workers. Chapter III: Deals with their significant fight and organization in times of deep changes in the city.

The development of timetable in educational institutions at the beginning of a semester is a complex and lengthy process for course coordinators or responsible, for it must meet various needs of those involved. The situation worsens when each teacher is available to teach classes only in some periods of the week. As the grid generation process is very specific to each institution, as each has its restrictions, it becomes difficult to create a solution that meets all institutions. To assist this process, performed manually in many institutions, this work aims, using the concept of genetic algorithms to create a system that generates a timetable in minutes that meets the specific of course of Analysis and Development Systems at the Federal Institute of Triangulo Mineiro, college Uberaba.

The technique of clustering analysis is an important tool in scientific research, it can be used in various fields of knowledge such as medicine, biology and statistics. To group data in clusters is a way to reflect the internal data structure and identify classes present in this clusters so within the same class there is homogeneity and there is heterogeneity between different classes. There are three types of clustering methods used to find optimal partitioning: hierarchical methods, methods based on graph theory and methods based on objective function. In this study we used the objective function algorithm based on Fuzzy C-Means and also the bootstrap resampling technique. The idea is to vary the cloudiness index in order to find the best value to be used for sorting the databases: Iris, Wine and three other artificial databases, consequently obtaining better partitioning results. The quality of the partitioning is based on traditional measures of comparison such as Crusade Classification (Acc), F1, Hubert (Hub), Jaccard, Random index (Rand) and Fowlkes and Mallows (Fowlkes). The results obtained so far show that the best range for the cloudiness index is between 1.04 and 1.2 for the contents of measures adopted.

The use of computer systems and artificial intelligence techniques to solve real world problems are increasingly common. In the nutrition area it is not different and, in Brazil and worldwide, systems are found to aid the prescription of food menus and diet formulation. The purpose of this paper is to present a methodology for prescription food menus and diet formulation, prioritizing the principles of healthy eating, emphasizing the variety of colors, combination of flavors, texture balance, the breaking of monotony and food supplying of all nutrients, besides contributing to the disciplines of Computer Science applied to Nutrition of the Federal Institute of Triangle Mineiro. To analyze this methodology, it was created a computer system using Genetic Algorithms to find satisfactory solutions in an acceptable time on a wide table food prepared in portion sizes. The experimental results were satisfactory, proving the effectiveness of the methodology.

Obtaining a suitable and trustful software development process, with good quality and that not requires great time in generating artifacts is a strong motivation to respond to market demands. Therefore, it requires strong research. One of the great challenges in this process is to appropriate different software development methodologies to the reality of an Information Technology group task force. This research proposes to adjust a unified process based methodology in order to adapt, particularly, to the software development within the public sector. One of the reasons for this proposal is based upon the fact that none development pattern has been established in such groups, yet. The present study is related to integrated systems that have Government Resource Planning (GRPs) characteristics. As an application model, three projects that have similar complexity aspects and task force characteristics have been used. These projects were undertaken by distinct times within the software factory of the Instituto Federal de Educação, Ciência e Tecnologia do Triângulo Mineiro IFTM. In order to reach established goals the research was conducted during six months and has presented quantitative results when taking the definition of standard patterns and artifacts generation into account. Therefore, this research conducts to apply the obtained results in Institutions that holds similar characteristics.

IP networks have become an increasingly protable option over traditional communication networks. Despite the advantages of VoIP compared to PSTN, it is not possible to replace one technology by the other instantly, due to the complexity involved. This implies a transition period in which the two technologies will coexist. In order to make this feasible, there must be a system for mapping E.164 numbers (used in the PSTN) to URIs (used in the IP network). In this context, the ENUM protocol is gaining prominence as the most promising solution. However, it is not very spread yet. In addition, there are technical issues and especially political and economic interests that need to be worked so that this protocol can be popularized. Regarding technical issues, there is a shortage of tools for the study of this protocol. Thus, this dissertation proposes a simulation platform that enables the study of the ENUM protocol. The project design of the simulator was based on experiments carried out in the laboratory, the proposition of mathematical models and, subsequently, implementation, integration and validation of the simulator. The results indicate that the simulation platform rightly describes the real system considered. The results also proved the success of the proposed modeling strategy. In addition, new modules were developed for the NS-3 simulation environment, oering new opportunities for researchers.

Education institutions seeking to support their expansion strategies and decision making. For this they need tools that provide them with relevant information from data previously stored, these data should be explored in all its granularity in order to find patterns and trends that manages knowledge, especially when a particular point of interest is necessary. However, with the increasing use of computing resources to store complex transactions from simple logs of users, the number of connections between the data and the amount increases considerably, this makes it necessary to find new ways and methods of information visualization that allow navigating through this data and present them to the user. Thus, this study aims to investigate ways and methods of representation and interaction, enabling create a System Information Retrieval able to extract relevant information from these data volumes. Thus, with the literature review and analysis of the state of the art tools that explore the interconnectivity of data through a technique called Data Network, is proposed the architecture of a system using information visualization techniques associated with data an educational institution, presents through visual artifacts, academic indicators. Finally, we present and discuss the results obtained by means of a case study in an educational institution.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The control of the documents flow was always a target of general interest, be for information s management that it represents or as results to stakeholders. This paper presents the prototype of a visual tool for monitoring the flow of documents through the use of computational resources based on information visualization techniques. Thus, in order to present a differentiated metaphor from those already implemented in systems with such purposes, this prototype allows users to record and monitor any type of administrative event in a more intuitive, through interaction with graphical or manipulation of the information representation. So, visualization techniques are investigated to provide resources to do the perception and interaction of users with information easier. In this context, the manipulation refers to change the scenario of the documents´ flow by user demand.