RCAAP Repository

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

This work aims to diagnose and analyze the solid urban residues from Tupaciguara MG. The specific objectives are: review the laws relating to the issue; make a succinct approach of Tupaciguara; contextualize what is done in the city with the solid urban residues; describing the private solid urban residues; and analysing the city s actions related to the theme in question. The methodology used was: a bibliographic survey; submission to the project to the Comitê de Ética e Pesquisa (Ethics and Research Committee) from Universidade Federal de Uberlândia; analysing the collection s structure and final residues disposal in the city; classifying the private solid urban residues in Tupaciguara from field trips and observations; estimating the number of establishments in town; through interviews and photographic records from researches, final solid urban residues disposal in the city and field trips. From the physical private solid urbans residues classification in Tupaciguara we could notice that the biggest private solid residues percentage in the city is from organic substance with something around 34%, plastic 27%, paper 14%, others (such as toilet paper, diapers, shavers, batteries, etc.) 9%, ferrous metals 6%, glass 5%, fabric 4% and styrofoam 1%, remembering that these data were calculated by weight rather than by volume of materials. At the end if there are suggestions for improving the collection s system and final disposal in the city which was developed from data analysis.

The issue accessibility to the disable people has been reason of great debate in some segments of the society, mainly to the economic sector. In the specific case of transportation, either urban or interurban, there are adequacies necessary to make it accessible, mainly to the disable people. The general objective of this work was to analyze the accessibility of the people with physical disability in the urban public transportation regarding the fulfillment of the laws and technical regulations related to the subject. The specific objective was to evaluate the accessibility of the public transportation service offered by the city of Uberlândia, Brazil using the results from a survey with disable users. In addition, physical spaces were observed, beginning with the sidewalks, which are used for the trips by foot, as well as equipments and vehicles used in the deployment of the public transportation service. In the public transportation system of the city of Uberlândia, Brazil it was verified what was already deployed, how was it working and if the service is in according to the existing laws. In the end, some directions were presented for orientation of the administrators and operators in the deployment and adjustment of the service. It is expected that this work provides to the readers a better understanding of the necessities of a public transportation that can be used by any person, despite of his/her physical condition, making possible the creation of a critical visualization by public administrators and operators in the execution of projects for the deployment and adaptation of urban public transportation systems with autonomy and safety to passengers.

This master dissertation aims to evaluate the use of Electronic Devices for Enforcement of Speed MEV on the reduction of traffic accidents in urban area, mainly the ones related to the drivers exceeding the speed limits. It was evaluated some intersections and a monitoring circular area surrounding it with a 500 m radii where the MEV was installed in order to verify if the accidents were not transferred to this area. It was used the default procedure by manuals from the Brazilian Ministry of Transportation which deal with the evaluation of the before and after measure to mitigate traffic accidents. Based on a visual observation of the number of registered traffic accidents it was concluded that one can not say that an accident migration occurred due to the deployment of the MEV. It was also concluded that the occurrence of traffic accidents is a statistical phenomenon due to chance and their variability was due to the random nature of accident occurrence. It is expected that this work gives more precise insights to the local administrator to control the traffic in urban areas.

The fractal compression is an emerging digital image coding technique which explores the self-similarity present in digital images, showing good fidelity between the original image and the reconstructed image, achieving high compression rates. However it has some weaknesses and because it demands a considerable computational complexity commonly is used the assistance of one or more techniques to meet those needs. This research presents a model which combines fractal coding and vector quantization (VQ). In addition, the time spent in choosing geometric transformation (isometry), which is an important step of fractal coding, is minimized by being made in the frequency domain by the DCT (Discrete Cosine Transform) inner product. The LBG (Linde_Buzo_Gray) algorithm is used to designate a generic codebook that replaces the traditional domain-pool of a fractal coder. The result is a hybrid coder with better performance than the pure fractal coders that preserve the visual quality of the reconstructed image and reaches high compression rates.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The switched reluctance generator emerged as an alternative generator and grew in interest among the scientific community during the last decade. It has a simple construction and comes up as a competitive option when one deals with variable speed applications and also when power electronics is required. Nowadays the most aimed applications are the aircraft applications, hybrid or electric vehicles and wind power. This machine has a doubly salient structure without copper in the rotor. The coils are concentrated in the stator poles. Thus, there is low copper and iron consumption and, because of it, this machine is closer to the modern environmental requirements. The switched reluctance generator driving uses power electronics and needs continuous information about the rotor position to drive properly the switches of the phases. The optimal design for this machine is still been established from the experimental results. Many operational details are under investigation. The machine has two different electrical circuits: one for the excitation and other when the load is fed. It is possible to insulate those two circuits and because of this it is also possible to reduce the electronic switches count. This work is helpful to understand how the SRG works. To get it the goals were to build a mathematical model for this machine and to simulate its operation. And than to know how it dynamically conducts. A prototype was constructed and used to test some driving circuits with it. Also it is presented an extensive comparative study. With this all this work presents a contribution for the development of this kind of machinery.

Universidade Federal de Uberlândia

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

This study demonstrate the importance of Distance Education as respects on-line distance learning. It intends to discuss the possibilities of this type of learning: the credibility of distance education platforms, the use of metaphors in the creation of referentially explicit graphic interfaces, the construction of educational programs utilizing graphic libraries and efficient program languages and, further, the proposal for an on-line distance learning platform monitored by the apprentice. It concludes that the utilization of distance laboratories is a way of breaking down barriers, creating conditions that make on-line teaching an educational system that will be acceptable and will promote efficiente learning. Besides this, the proposal to create an on-line distance learning plataform monitored by the apprentice can be an important contribution toward improving the teaching-learning process.

Due to the increasing demand of consumption, the electric energy systems have faced, in the current times, problems with its operation, being the voltage control one of the most relevant matters. To provide means to solve such problems, the use of static compensators has emerged, amongst others, as a classical alternative. Although the modern solutions are mainly based on power electronic equipments, in the past, an old fashion compensator using saturated core reactor had been largely used. This is composed, basically, by a magnetic core with special windings operating in parallel with a fixed capacitor. This equipment, due to its robustness, low cost, minor maintenance requirement and good performance, consists in an attractive alternative in relation to electronic proposals when the voltage requirement control is not so strict. However, the technology of this product, appeared in the year of 60, is quite rare documented. This has created a great lack of information regarding the project and construction of these compensators. In this context, the present thesis aims at searching for mechanisms to support the design of the saturated reactor. The searched process, amongst other properties, focuses the optimization of losses associates with the operation of the device. On the basis of these procedures, in addition to computational tools utilizations to predict the equipment performance, a real size saturated reactor is designed, constructed and tested. The results are then used to validate two software (FEMM and SABER) chosen to evaluate the equipment performance analysis before the final construction.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This work analyzes the technical and regulatory aspects of reactive power supply ancillary services of synchronous generators and emphasizes that Brazilian rules do not stimulate investment for such purpose and this can degrade those resources. In the past, the electrical worldwide systems used to have a centralized public utility which could include the several costs of ancillary services for electric power supply in the final price of the active power. After the privatization and decentralization, there was the need to separate the remuneration for such ancillary services. The resolutions that rule the reactive power ancillary services of synchronous generators have developed differently in several world regions. In this work it is given a description of some foreign legislations, which are then compared to the present status of Brazilian legislation, indicating its questionable aspects. Indexes are proposed for the selection of generators to supply reactive power to some electric power system area. It is proposed the public bidding for this supply taking the indexes into account, so that the price will depend on the effective contribution of each generator to the voltage rise in the target area. Simulations are presented to illustrate that the generator choice depends upon its localization. The need of reactive power support to improve the security margin against voltage collapse can be indicated by several indexes. It is shown a top view of the voltage collapse proximity indicators, with emphasis to those selected for this work. Often the electric power system operators call for a reactive power redispatch for voltage profile correction, but it is shown that sometimes this procedure leads to a risk of voltage collapse The dynamical behavior of synchronous generator excitation systems is very important for the reactive power dispatch. The operator requirements from Brazil, USA and Canada are presented. It is proposed a technique for voltage regulator adjustment, taking into account the time constant, the regulation error and the ceiling voltage, with illustration by means of simulations. Concluding, several suggestions are synthesized towards the evolution of the legislation concerning to reactive power supply from synchronous generators.

This work aimed to assess the relevance of the most common clinical tests and risk factors current used to establish the probability of falls among the elderly. 85 seniors took part in this research, both male and female, fallers and no fallers, 60 years old or more. This population was analyzed and divided into seven classes: (1) The whole population; (2) The whole female population (Female Group FG); (3) The whole male population (Male Group MG); (4) Female group 1 (FG1: 60 to 69 years old); (5) Female group 2 (FG2: > 70 years old); (6) Male group 1 (MG1: 60 to 69 years old); (7) Male group 2 (MG2: > 70 years old). The following criteria were considered in the analyses: quantity of falls, daily medication (Med), Body Mass Index (BMI), Calf Circumference (CC), Waist Circumference (WC), grip strength (MF), Dynamic Gait Index (DGI), balance (Berg Balance Scale BBS), mobility (Timed Up & Go TUG), cognitive state (Mini Mental State Examination MMSE), Life Satisfaction (LS), Physical Self-Efficacy (PSE), Functional Capacity (FC) and Fear of Falling (Falls Efficacy Scale International - FES I Brasil). Although 60% of the whole population did not fall, FG falls more frequently (53%) than MG (14%). The age range analysis shows that FG2 falls the most (FG2: 62%; FG1: 39%; MG2: 27%; and MG1: 6%). The Spearman Test (p &#8804; 0,05) revealed that the relationship fall x criteria (significantly correlated) varies according to the group, as follows: FG: Med, WC, MF, DGI, FES I Brasil, TUG, LS, FC; FG1: there was no relevant correlation; FG2: DGI; MG: BBS and TUG; MG2: FES I Brasil (p<0,001). The covariance was assessed for all indices in relation to the variable fall. According to those analyses, the most relevant elements are: FG: Med, DGI, and FES I Brasil; MG: MF, DGI, BBS, and TUG; FG1: BMI, WC, FES I Brasil, and TUG; FG2: Med, CC, and DGI; MG1: MF, DGI, and TUG; MG2: BBS and FES I Brasil. The results shows that the proper risk factors and the assessment tools to be used to evaluate the probability of fall among the elderly are significantly different for males and females, as well as among the same sex but at different age range. It is therefore suggested that the assessment protocols should be developed taking these differences into consideration, in order to ensure better efficacy, better directions for the treatment and earlier interventions. Such specificity would contribute to reduce the amount of falls and, consequently, improve the quality of life of the elderly population.

This thesis presents a study of architecture for virtual environment distribution as support tool for learning multidisciplinary projects. Different distribution platforms have been evaluated with the objective to identify the one that with more efficiency allowed exactly that occurred alterations in an environment modify the behavior of others, that these are related to other areas of the knowledge. Building prototypes under the platform chosen for the distribution, following same methodology (modifying aspects of the data model) and having the latency, scalability and extensibility as method of comparison had demonstrated to which the best choice for building multidisciplinary virtual environment. Each prototype was constructed on the basis of distribution algorithms that had allowed the system to function correctly in possible situations of errors. Virtual environments of Biology (landscape with plants, water, light and land) and Chemistry (membrane and molecules) had been used having the phenomenon of the photosynthesis as study of case and relation between two environments. The system was evaluated by professors and students and the reached results had allowed concluding that it is efficient and applicable.

A great number of researchers believe that problem resolution is inherent from the great part of the teaching and learning processes. It is considered that this methodology presents a better effectiveness when applied cooperatively, in other words, an apprentice improves your acting in solving problems when accomplishes his activity in cooperation with other apprentices. In the context of computational systems applied to learning, Virtual Reality (VR) is emerging as a technology that motivates the apprentice, since it allows the navigation, visualization, manipulation and interaction with virtual objects of its learning environment. In this context, this work presents a proposal that allows the use of VR to offers support to the resolution of problems through the cooperative learning. For this, the learning foundations will be considered by experimentation and the effectiveness of theories and constructivities pedagogic principles. As case study it was chosen for developing the project in the Physics ambit. The present work approaches and bases its proposal through the state of the art description of the research in this area. It makes an analysis, supplies specifications of the project, introduces details of system developing, discusses that evaluation and finally, presents the conclusions and proposals future work for this project.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

As the Internet has become an enormous interconnected network, the information security today is very important to guarantee confidentiality, integrity and availability of computing resources. Advanced Intrusion Detections Systems (IDS) should be capable of identifying malicious actions that may compromise these guarantees, as quickly as possible. In this work, we present a hybrid approach for the IDS, with two different techniques: wavelets and artificial neural network. The wavelet is used to indicate to detect anomalous behavior on the network, while the neural networks are used to classify the attacks. A prototype was developed and evaluated data from simulation tests, on laboratory network and the KDD99 database. Besides the analysis of results of the other approaches, was also carried out a comparison with the learning vector quantization. Good results were obtained in all experiments, this demonstrating that the approach is very promising.

This research developed a method of evaluation for computer tools for education (FCE), called Structure Cognitive for Education Technologies Constructivists (ECoTEC). This methodology detects the construction of structures of logical-mathematical thinking through the proposed activities on FCE. In the ECoTEC conception was used a strategy of analysis which includes: organization of cognitive structure of logical-mathematical thinking according to Piaget operative theory; the differentiation of essential concepts of this theory; and the deconstruction of Piaget operative theory. It was made an ascendant unfolding of principal concepts and organized them in a sort of integrated network and additional. The structure allows comprehending the structures of thinking in the concrete operative periods and formal operative, according to the operative activities, the interaction and the cooperation. From this structure it was established a process of measurement. It was used as a strategy for development the paradigm GQM (Goal/Question/Metric), a technique for identification of significant metrics. To automate the collection for information to the user and assist in calculation of the metrics for the characterization of FCE was developed an instrument of optimization called Web-ECoTEC. The validation of Web-ECoTEC while methodology of evaluation of FCE revealed his potentiality to characterize these tools according to the structure of thinking developed. The evaluations generated by the methodology can guide teachers, educators and educational professionals in the selection of FCE, since that these evaluations showed the structures of logical-mathematical thinking which can be used with the FCE evaluated. The utilization of Web-ECoTEC for validation, also presented efficient in the collection of answers and in generation of results of characterization of FCE.