RCAAP Repository

Mestre em Ciências

This thesis presents the development of a Distributed Virtual Environment with the use of computational techniques that, associated to Virtual Reality, as a tool to support project in education to Internet. Considering the related work, you can see that the currents Distributed Virtual Environment did not explore techniques to improve the bandwidth and latency. In face of this, the objective for this dissertation, the development of an online multiplayer 3D game with Virtual Reality techniques. The principal idea is that through Distributed System and VR techniques, can demonstrate efficiency on interaction between players. For this reason, it was proposed the case study LudosTop, it is game Quarto and can aid the educator's activity. Such learning atmosphere returns to mathematical contents and it has, as public, students of the Fundamental Teaching. The design of the software bases on the image of a park. From within of the park, the user has the possibility to play ( Quarto ) a match against other player over Internet. The objective of the game is to align geometric solids with common attributes, giving possibility of add, at a certain moment of match; a third or fourth person as observer. The work included the analysis of some educational games, such educational systems served as theoretical and methodological referential for the elaboration of the proposed software. Therefore, a potential technology were evaluated to creation and distribution of Virtual Environment, where it can apply distributed virtual environment (DVE) techniques and make seen advantages in application to improve performance network communication. The work includes description and implementation of virtual reality s techniques with technology Torque Game Engine though C++ Programming Language, OpenGL Library and Toque Scripting API. The 3D Multiplayer Game was tested with children of the fundamental teaching, generating, finally, a report that indicated absolute contribution this experience.

Attenuation caused by rain can cause serious impact on communication services by radio that operate in frequencies over 10 GHz. For frequencies above this, more damage caused by rain occurs in satellite or terrestrial links. In general, to calculate with a degree of certainty the attenuation caused by rain in a certain locality, a history of precipitation is needed and more than this, the history must be long, that is, a period of registers of over 10 years of observation. The data in this study was obtained at the National Institute of Meteorology and from the book Drenagem Urbana published by Companhia de Tecnologia em Saneamento Ambiental de São Paulo. Information was obtained from this book concerning the intensity of rain which had a return prevision (when the rain can occur again). This information was of 2, 5, 10, 15, 20 and more years. The intensities of the return of rain of 2 years were converted to the equivalent in 1 year. With the data vector of 1 year, it is possible to arrive at that referent to 0,01% of this time, or 53 minutes, and apply it in the mathematical routines used to find the attenuations caused by rains in the selected cities. Data from ten cities was collected: Rio Branco (AC), Porto Velho (RO), Cuiabá (MT), Porto Alegre (RS), Curitiba (PR), Belo Horizonte (MG), Salvador (BA), Natal (RN), São Gonçalo (PB), and Quixeramobim (CE). These were chosen due to the fact that, as a group, they form a geographical corridor covering almost the totality of the Brazilian territory that is mentioned in the literature which refers to calculations of attenuation due to rain [3] and [4], with values of rain equal to 0,01% of the time either by the CCIR model that is 95 mm/h, or by the Crane model that is 67mm/h. Although this study does not intend to question the validity of these values in calculations, they marked the boundaries to compare with those obtained for each city, which are obviously different, not only because of the distance between them, but by the known annual rate in the regions. Even considering the fact that intensity rates of short rain tend to approximate for the several regions, the rates for the chosen cities are different from each other and these in turn are different from those recommended by the models mentioned. With the rain intensity of each city being known, it was possible, therefore to calculate the attenuations of signal using the models, obtaining the statistics and probabilities of occurrences either in satellite or terrestrial links.

This dissertation presents an application of Virtual and Augmented Reality, having as main focus the study of the magnetic field created by a single-phase engine of induction during its functioning. Virtual Reality and Augmented Reality potentially emerges every days, due increasing number of its applications in the most varied areas of the knowledge. One of the most benefited is Education. Therefore, these technologies becomes supporting tools for education, for assisting in the perception and interaction of the students in diverses subjects. The visualization of the magnetic field is related to strategies of use of ferromagnetic elements. Such fields, the example of others (Electric Field, Gravitational Field) have threedimensional characteristics. Since great part of the referring images to this physical phenomenon is static what most of the time it finishes making it difficult the learning of this subject. In this work, the Magnetic Field could be visualized, for the user, with use of Virtual Reality or Augmented Reality. The study element will be the Magnetic Field that is generated in an electric engine (of single-phase induction). It is intended, by means of this boarding, to identify the advantages of if using the techniques of Virtual Reality and Augmented Reality in relation the other forms of visualization of the magnetic field.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Universidade Federal do Triângulo Mineiro

This work describes a micro controlled-based device for over current protection and online monitoring of induction motor operation, able to replace with some advantages the traditional over current thermal relays. It allows real time monitoring of induction machine currents and over current protection, with programmable current x time characteristic. The typical current x time thermal relay curve can be easily programmed in this device and both the curve and setting points of operation can be altered online with the motor in operation. The device has a network communication interface for remote control and operation monitoring in a remote PC. Due to the programmable characteristic, the hardware can be used for different ranges of motor sizes and rated powers. The work shows details of design and programming, and presents experimental results obtained with a prototype developed in laboratory.

Nowadays, the presence of computers is noted, even subtle, in almost every area of human knowledge and activity. The advantages emerged by computers are many, but there are still drawbacks that need efficient solutions. The tech devices and audiovisual ways of communication between the user and computers are still a great challenge, because to use successfully these devices, is needed to the user to learn the new unnatural ways of interaction, like clicking and typing. There are some more natural approaches of interfaces, and One of them is known as Augmented Reality. Augmented Reality has as goal to provide people, with more intuitive ways of interaction and visualization, close to those that happen in real world. So, it s possible to interact with an object using the hands as main way of interaction, inspect it and view it in it s natural shape. The interaction elements are brought to the real world, instead of classic interaction with computers, where the user has to get inside the computer s world and adapt himself to it. The applications for Augmented Reality are countless, and results can be already seen in several areas like Education, Training, Entertainment and Medicine. The focus of this work is on the integration between Augmented Reality and Health Science. Traditionally, the patients have limited or none knowledge about Medicine, which by the way stops him to interpret information like x-ray and electrocardiograms. So, very often even after clarifying with the specific professionals, remain doubts about organ function, disease particularities and even interpretation of tests. The system proposed in this dissertation, has as goal to provide a friendly and intuitive interface in Augmented Reality for heart beat viewing. The data needed to visualization are received from very heterogenic fonts, which goes from simple fixed values up to real time capture and viewing from heart beat sensors. Trough markers and a viewing device, the users are allowed to view in its own chest the virtual animated heart and it s beating in real time, answering to his own heart beating. The developed system should be used as bases to studies on health schools, as well to view by patients, providing a way of help learn and interpret of medical data.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

This research presents a mathematical model for a voltage regulator transformer with on load tap change, in order to perform dynamic stability studies in an electrical system. It permits verifying the behavior of the voltage, current, frequency, active and reactive powers, after disturbances in this system. It can simulate and evaluate electromagnetic and electro-mechanical transients caused by its operation which can affect the quality power of the electric system. The model of the transformer is divided into three different parts, which represent the voltage regulator transformer of a substation. Those parts are: the modeling of the transformation system, the modeling of the commutation mechanical system and the modeling of the electro-mechanical system of the on load tap change. The mathematical model implemented in the ATP program consists of linear and non-linear inductors that represent the magnetic flux through the air and through the core, respectively. The non-linear inductors are represented by the transformer s magnetization curve. The TACS routine in the ATP program was used to simulate the on load tap change. The implemented model presented a good performance regarding the simulations of the transformer operative modes in a substation.

This work presents a new approach for PFC boost converter controller, which sets the priority of the controller to high power factor, under normal utility condition, or output voltage regulation, under sag condition. The new controller is based on modification of chip 3854 feedback loop. The monitoring system has a LPC2138 microcontroller that modifies the 3854 feedback loop depending of the energy network condition. This proposal conceives a ride-through capability improvement of PFC boost converters to hard voltage sags. Experimental results under normal and sag conditions are shown. Through these results it is possible to compare the performance between the proposed system and the ordinary PFC converter.

The present thesis aims firstly to argue theoretically, of what occurs in carbon steel and silicon steel plates for electric ends, when used in transformers, electric motors and generators, and other electromagnetic devices. Secondly, experimental data and results are used to justify the "new" concepts adopted the analyses and conclusions drawn with samples of these materials. The total losses in the iron and the magnetic permeability, important in the choice of plates, are investigated taking in consideration their main function of magnetic flow amplifyers, and, therefore, more representative values are searched. For the fact of the measurement currently to be effected in the Epstein square with 50/50 values (0° and 90°), is considered, remaining the same device, to change themselves in plate GNO, for 25/50/25 (0°, 45° and 90°) with the proven certainty, gotten experimentally, that these values reflect more adequately what it occurs with plates mounted in the stators of engines of induction and alternating chain generators. In one of the studied samples, the difference between the two methods reaches 86,2% in the relative permeability, and 4,4% for the total losses in the iron, with B = 1,5 T, concluding itself for the immediate necessity of the change in the assay methodology.

The use of a computer system for vehicle routing is essential for the competitiveness of companies working with distribution of resources and products. Despite high cost, such a system ofiers a guaranteed return on investment made. Using a Metaheuristics techniques combined with the resources currently ofiered by web, free development tools can be developed routing systems with features, performance and eficiency very close to commercial systems. In this work, was first performed a study of the theoretical foundations of Genetic Algorithms. Using the Java programming language, is implemented a set of routines common to the AGs, in the form of a library of development. With this routines, was developed an algorithm routes of vehicles with support for multiple routes and various types of calculations of costs between locations. To improve the performance of the algorithm implemented, we used the technique of local search 2opt, and are thus resulting in a Hybrid Genetic Algorithm. This algorithm was used as a core for the development of a functional prototype of a web vehicles routing system capable of handling the geographical coordinates of settlements in land surface and create routes on a map of vehicles considering the vehicular trafic routes . The system also generates a detailed list of routes and close to describing direction to be taken on each site to facilitate the work of a driver of the vehicle.

Two systems to control the computer s and video game s use were developed on this work. By using a database for the control of the computer in which the restrictions of use for each user will be stored, and having as a graphic interface and agenda which will allow the administrator to interact with the system. Yet on this control of computer s use, the entire system will be controlled through a device that will be linked to the computer. The repealing of this device will be explained as a violation to the program, what will be stored in the database too, the administrator will have the mastery on all the information that an average user does. At any moment, the administrator will be able to print a report about what each user did. As far as the control of the domestic plug of energy, the administrator will be able to insert a determined restriction for each kind of plug. The control will also be done by using a microcontroller, and the data will be sent from the USB protocol. The devices were tested and were taken as efficient systems, although as future work will be able to be implemented a system, which, through the help of a computer, will be able to become available a schedule for a specific user, according to presented damages.

The objective of the project is to demonstrate the use of the information s technology and geoprocessing, in intention to extend the city knowledge and to democratize the use of the information in all levels of the public administration and in the society. Presenting concepts and strategies of data modeling and techniques of data migration of different information systems in the consolidation of the Corporative Data base, the work presents the necessary stages to development and implantation of a Managemental Information System using geoprocessing tools, supporting Santos City Administrative Modernization Project. The difficulties in conciliating systems sequential archives legacies to a relationary data base, the change of mentality of the analysts of systems and programmers, the documentation s methodology, security techniques, the search of a geoprocessing solution whose modeling was opened for the creation of an only data base that allowed to add information of all the municipal sectors, also is detached in this work. The challenge of this project is to spread out the idea that, exactly small city halls which possess computer science sectors, can with an efficient management use its internal resources for the implantation of Information Managing System becoming independent for any type of maintenance or implementation of its applications, diminishing stated periods and costs.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Interest in discovering the reasons for student s lack of interest/stimulus in Geography as a school subject gave rise to this study. Thus, we examined the educational methodologies used in the pedagogic practice developed in the fifth grade of the elementary school in Brazil (Uberlândia) and in "sixiéme" in schools in France (Paris). We have redeemed the interest and attraction that this subject could have in the schools by questioning the old conception that the teaching of Geography is not important, because it only demands memorization and that it does not develop the thinking and the critical spirit of the students. Our research shows signs for the improvement of the methodology used in present didactic books by means of: the images and the language of the midia; field work; the valorization of maps; and of the students daily routine as a start of the pedagogic practice, whenever possible. By using these pedagogic practices, we understand that the reconstruction of geographical knowledge and the redimensioning of the educational practices are possible. In this manner the delights of learning Geography as a school subject can be accomplished. The renewal of our daily pedagogy in the classroom becomes more and more important if we wish to impart to the students the conditions necessary to assimilate the knowledge which study of Geography provides for a greater understanding of challenges we face in today s world.