A survey of control architectures for autonomous mobile robots

MEDEIROS, Adelardo A. D.A survey of control architectures for autonomous mobile robots. J. Braz. Comp. Soc., Campinas, v. 4, n. 3, abr. 1998 .Disponível em: Acesso: 27 set. 2010.

Representation of odometry errors on occupancy grids

SOUZA, Anderson A. S. ; SANTANA, André M. ; BRITTO, Ricardo S. ; GONÇALVES, Luiz Marcos G. ; MEDEIROS, Adelardo A. D. Representation of Odometry Errors on Occupancy Grids. In: INTERNATIONAL CONFERENCE ON INFORMATICS IN CONTROL, AUTOMATION AND ROBOTICS, 5., 2008, Funchal, Portugal. Proceedings... Funchal, Portugal: ICINCO, 2008.

Contribuição da Geodésia ao monitoramento costeiro do Litoral Setentrional do Rio Grande do Norte, área de influência da indústria petrolífera

The general objective of this thesis has been seasonal monitoring (quarterly time scale) of coastal and estuarine areas of a section of the Northern Coast of Rio Grande do Norte, Brazil, environmentally sensitive and with intense sediment erosion in the oil activities to underpin the implementation of projects for containment of erosion and mitigate the impacts of coastal dynamics. In order to achieve the general objective, the work was done systematically in three stages which consisted the specific objectives. The first stage was the implementation of geodetic reference infrastructure for carrying out the geodetic survey of the study area. This process included the implementation of RGLS (Northern Coast of the RN GPS Network), consisting of stations with geodetic coordinates and orthometric heights of precision; positioning of Benchmarks and evaluation of the gravimetric geoid available, for use in GPS altimetry of precision; and development of software for GPS altimetry of precision. The second stage was the development and improvement of methodologies for collection, processing, representation, integration and analysis of CoastLine (CL) and Digital Elevation Models (DEM) obtained by geodetic positioning techniques. As part of this stage have been made since, the choice of equipment and positioning methods to be used, depending on the required precision and structure implanted, and the definition of the LC indicator and of the geodesic references best suited, to coastal monitoring of precision. The third step was the seasonal geodesic monitoring of the study area. It was defined the execution times of the geodetic surveys by analyzing the pattern of sediment dynamics of the study area; the performing of surveys in order to calculate and locate areas and volumes of erosion and accretion (sandy and volumetric sedimentary balance) occurred on CL and on the beaches and islands surfaces throughout the year, and study of correlations between the measured variations (in area and volume) between each survey and the action of the coastal dynamic agents. The results allowed an integrated study of spatial and temporal interrelationships of the causes and consequences of intensive coastal processes operating in the area, especially to the measurement of variability of erosion, transport, balance and supply sedimentary over the annual cycle of construction and destruction of beaches. In the analysis of the results, it was possible to identify the causes and consequences of severe coastal erosion occurred on beaches exposed, to analyze the recovery of beaches and the accretion occurring in tidal inlets and estuaries. From the optics of seasonal variations in the CL, human interventions to erosion contention have been proposed with the aim of restoring the previous situation of the beaches in the process of erosion.

Medidas de parâmetros morfológicos e funcionais do Coração em brasileiros: um subestudo do primeiro registro multicêntricos latino-americano em ressonância magnética cardiáca

There is no data about cardiac measurements em Brazilians obtained by CMR. This a muldisciplinary study with the objective of obtaining measurements of the left ventricle (LV) and right ventricle (RV) diastolic diameter (Dd), systolic diameter (Ds), diastolic volume (Dv), systolic volume (Sv), ejection fraction (EF) and myocardial mass in Brazilians. One hundred and seven (54 men and 53 women, mean age of 43.4 ± 13.1 years) asymptomatic individuals without heart disease were submitted to cardiac magnetic resonance (cMR) studies using steady state free precession technique. The means and standard deviations of the parameters of the LV and RV were respectively: LVDD = 4,8 ± 0,5 cm; LVSD = 3,0±0,6 cm; LVDV = 128,4±29,6 ml; LVSV = 45,2±16,6 ml; LVEF = 65,5±6,3%; LV mass = 95,2±30,8.1 g; RVDD = 3,9±1,3 cm; RVSD = 2,5±0,5 cm; RVDV = 126,5±30,7 ml; RVSV = 53.6±18,4 ml; RVEF = 58.3±8,0.0% and RV mass = 26,1±6,1 g. The masses and volumes were significantly higher in men, except for the LVSV. The RV EF was significantly higher in women. There was inverse correlation between RV systolic volume and with age, being more significant in men. This study describes for the first time benchmarks for cardiac measurements obtained by CMR among asymptomatic Brazilians individuals without heart disease and demonstrated differences according to sex and age

FERRITINA: intervalos de referência para adultos no Estado do Rio Grande do Norte

Ferritin is a protein composed of heavy and light chains, non-covalently linked and which accommodates, in its core, thousands of atoms of iron. Furthermore, this protein represents the stock of iron in the body and it is characterized as an acute marker and predictor of diseases, such as iron deficiency anemia, hereditary hemochromatosis and others. Considering the variability of reference values and the analytical methods currently available, the aim of this work was to propose 95% confidence intervals for adults in the State of Rio Grande do Norte, Brazil, after determining the average concentration of serum ferritin for both sexes, beyond its correlation with the age. We analyzed 385 blood samples, collected by venipuncture from individuals residing in the State, after 12-14 hours of fast. The populational sample had 169 men and 216 women between 18-59 years old, which filled a questionnaire on socioeconomic, food habits and accounts about previous and current diseases. The sample collections were itinerant and the results of erythrogram, fasting glucose, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, urea, creatinine, leukocyte count and platelets, beyond C-reactive protein, were issued to each participant, so that, after selection of the apparently healthy individuals, the dosage of serum ferritin was carried out. Statistical analysis was performed using the softwares SPSS 11.0 Windows version, Epi Info 3.3.2 and Graf instant pad (version 3.02), and the random population sample was single (finite population), for which the test of linear correlation and diagram of dispersion were also made. After selection of individuals and determination of serum ferritin, the most discrepant outliers were disregarded (N = 358, Men = 154/Women = 207) and the average value determined for the masculine sex individuals was 167,18 ng / dL; for the feminine sex individuals, the average value obtained was 81,55 ng / dL. Moreover, we found that 25% of men had values < 90,30 ng / dL; 50% ≤ 156,25 ng / dL and 75% ≤ 229,00 ng / dL. In the group of women, 25% had values < 38,80 ng / dL; 50% ≤ 65,00 ng / dL and 75% ≤ 119,00 ng / dL. Through the correlation coefficient (r = 0,23 with p = 0,003), it is possible to suggest the existence of positive linear correlation between age and serum ferritin for men. The correlation coefficient for women (r = 0,16 with p = 0,025) also confirms the existence of positive linear correlation between serum ferritin and age. Considering the analysis carried out and specific methods corroborating with the proposed benchmarks, we concluded that the average value found for men is higher than that found for women. Furthermore, this scenario rises with age for both sexes, and the 95% confidence intervals obtained were 74 ng/dL ≤ μ ≤ 89 ng/dL and 152ng/dL ≤ μ ≤183ng/dL for the feminine and masculine sex individuals respectively

Percursos para novas imagens: a produção audiovisual por não videntes

The purpose is to write a reflection on the audiovisual production by the visually impaired. The starting point for this research was a documentary video production workshop offered by the Instituto de Educação e Reabilitação de Cegos do Rio Grande do Norte - IERC / RN, with the participation of blind people with low vision and sighted employees of the institution. The research approach follows the precepts of complex thinking, where work is woven into the network, along with the researched. The theoretical framework is based on the theory of French sociologist Edgar Morin, and other important thinkers for this work, namely: Erving Goffman, Paulo Freire, Michel Foucault, Edward Said, Jacques Aumont, Phillpe Dubois, as well as scholars who think and theorize about his own condition and conduct discussions on the issue of blindness: Francisco Jose de Lima, Evgen Bavcar Jacques Lusseyran and Joana Belarmino. The research was formulated based on the statement in the interest of respondents to understand and produce visual images using video as a tool. In this sense, the methodology adopted approaches of action research in constructing the text and dialogue with the participation of those involved in the project. The technique of gathering the information was based on ethnographic description describing the dynamics of the workshop, the relationships between participants, relationship to the other that sees and the manner of operation of equipment. The main focus is the relationship based on dialogue of information, attitudes and ways of knowing from experience and capacity developed and obstacles for blind people to produce visual images using other benchmarks, such as touch, smell and time dimension and space, and add references that give new meaning to the guidelines based on visuality of ministering to the workshop. It is also held to discuss aspects related to the concept of image with sociological reflection about the audiovisual production made by blind people socially constructed and perpetuated by what Edgar Morin called cultural imprinting. Thus we attempted to walk the route with its obstacles and achievements in the production of new images that were seen

Professoras e projetos: concepções e práticas no ensino fundamental

The discussion we have established in this study is about how the practice is developing educational projects based on work with because the methodological choice of the teacher. The study of an ethnographic qualitative approach was conducted with a group of six teachers in two public schools in School Administrative Zone north of the city of Natal / RN. Data were constructed from semi-structured, reinforced by the direct observation of the practice of teaching of teachers. The goals outlined were to identify the reasons why the option for the project, listing the benchmarks that subsidized their construction, the observation of everyday experience in educational planning and development of projects developed. In the light of information we can notice a complex and even contradictory, which is confusing the concepts and practices are weakened. The analysis revealed inconsistencies between theory and practice in working with projects, the fruit of little theoretical development of teachers. The adoption of the project as a methodological option has meant a change in direction of the effective action didactic. Reflects on this situation, it was concluded that there is a need to broaden the understanding of the significance of this type of work, covering the different dimensions that involve the practice of research, research and training of teachers. Even preventing the intentions and initiatives of the teachers, it must be emphasized is the process of learning within an approach that focuses the process of learning in multiple dimensions, inter-relational, both the capabilities of students in the areas of knowledge.

Modelo de covariância bayesiana para seleção de protfólios de investimentos

The portfolio theory is a field of study devoted to investigate the decision-making by investors of resources. The purpose of this process is to reduce risk through diversification and thus guarantee a return. Nevertheless, the classical Mean-Variance has been criticized regarding its parameters and it is observed that the use of variance and covariance has sensitivity to the market and parameter estimation. In order to reduce the estimation errors, the Bayesian models have more flexibility in modeling, capable of insert quantitative and qualitative parameters about the behavior of the market as a way of reducing errors. Observing this, the present study aimed to formulate a new matrix model using Bayesian inference as a way to replace the covariance in the MV model, called MCB - Covariance Bayesian model. To evaluate the model, some hypotheses were analyzed using the method ex post facto and sensitivity analysis. The benchmarks used as reference were: (1) the classical Mean Variance, (2) the Bovespa index's market, and (3) in addition 94 investment funds. The returns earned during the period May 2002 to December 2009 demonstrated the superiority of MCB in relation to the classical model MV and the Bovespa Index, but taking a little more diversifiable risk that the MV. The robust analysis of the model, considering the time horizon, found returns near the Bovespa index, taking less risk than the market. Finally, in relation to the index of Mao, the model showed satisfactory, return and risk, especially in longer maturities. Some considerations were made, as well as suggestions for further work

RoboEduc: uma metodologia de aprendizado com robótica educacional

In this work, we propose a methodology for teaching robotics in elementary schools, based on the socio-historical Vygotsky theory. This methodology in conjunction with the Lego Mindstoms kit (R) and an educational software (an interface for control and programming of prototypes) are part of an educational robotics system named RoboEduc. For the practical development of this work, we have used the action-research strategy, being realized robotics activities with participation of children with age between 8 and 10 years, students of the elementary school level of Municipal School Ascendino de Almeida. This school is located at the city zone of Pitimbu, at the periphery of Natal, in Rio Grande do Norte state. The activities have focused on understanding the construction of robotic prototypes, their programming and control. At constructing prototypes, children develop zone of proximal development (ZPDs) that are learning spaces that, when well used, allow the construction not only of scientific concepts by the individuals but also of abilities and capabilities that are important for the social and cultural interactiond of each one and of the group. With the development of these practical workshops, it was possible to analyse the use of the Robot as the mediator element of the teaching-learning process and the contributions that the use of robotics may bring to teaching since elementary levels

Localização e planejamento de caminhos para um robô humanóide e um robô escravo com rodas

This work presents the localization and path planning systems for two robots: a non-instrumented humanoid and a slave wheeled robot. The localization of wheeled robot is made using odometry information and landmark detection. These informations are fused using a Extended Kalman Filter. The relative position of humanoid is acquired fusing (using another Kalman Filter) the wheeled robot pose with the characteristics of the landmark on the back of humanoid. Knowing the wheeled robot position and the humanoid relative position in relation to it, we acquired the absolute position of humanoid. The path planning system was developed to provide the cooperative movement of the two robots,incorporating the visibility restrictions of the robotic system

Infra-estrutura para avaliação e testes de protocolos sociais de comunicação em ambientes tridimencionais compartilhados

The advent of the Internet stimulated the appearance of several services. An example is the communication ones present in the users day-by-day. Services as chat and e-mail reach an increasing number of users. This fact is turning the Net a powerful communication medium. The following work explores the use of communication conventional services into the Net infrastructure. We introduce the concept of communication social protocols applied to a shared virtual environment. We argue that communication tools have to be adapted to the Internet potentialities. To do that, we approach some theories of the Communication area and its applicability in a virtual environment context. We define multi-agent architecture to support the offer of these services, as well as, a software and hardware platform to support the accomplishment of experiments using Mixed Reality. Finally, we present the obtained results, experiments and products

Mapeamento robótico 2,5-D com representação em grade de ocupação-elevação

This work introduces a new method for environment mapping with three-dimensional information from visual information for robotic accurate navigation. Many approaches of 3D mapping using occupancy grid typically requires high computacional effort to both build and store the map. We introduce an 2.5-D occupancy-elevation grid mapping, which is a discrete mapping approach, where each cell stores the occupancy probability, the height of the terrain at current place in the environment and the variance of this height. This 2.5-dimensional representation allows that a mobile robot to know whether a place in the environment is occupied by an obstacle and the height of this obstacle, thus, it can decide if is possible to traverse the obstacle. Sensorial informations necessary to construct the map is provided by a stereo vision system, which has been modeled with a robust probabilistic approach, considering the noise present in the stereo processing. The resulting maps favors the execution of tasks like decision making in the autonomous navigation, exploration, localization and path planning. Experiments carried out with a real mobile robots demonstrates that this proposed approach yields useful maps for robot autonomous navigation

Navegação cooperativa de um robô humanóide e um robô com rodas usando informação visual

This work presents a cooperative navigation systemof a humanoid robot and a wheeled robot using visual information, aiming to navigate the non-instrumented humanoid robot using information obtained from the instrumented wheeled robot. Despite the humanoid not having sensors to its navigation, it can be remotely controlled by infra-red signals. Thus, the wheeled robot can control the humanoid positioning itself behind him and, through visual information, find it and navigate it. The location of the wheeled robot is obtained merging information from odometers and from landmarks detection, using the Extended Kalman Filter. The marks are visually detected, and their features are extracted by image processing. Parameters obtained by image processing are directly used in the Extended Kalman Filter. Thus, while the wheeled robot locates and navigates the humanoid, it also simultaneously calculates its own location and maps the environment (SLAM). The navigation is done through heuristic algorithms based on errors between the actual and desired pose for each robot. The main contribution of this work was the implementation of a cooperative navigation system for two robots based on visual information, which can be extended to other robotic applications, as the ability to control robots without interfering on its hardware, or attaching communication devices

Plataforma Robótica de Baixíssimo Custo para Robótica Educacional

Robots are present each time more on several areas of our society, however they are still considered expensive equipments that are restricted to few people. This work con- sists on the development of control techniques and architectures that make possible the construction and programming of low cost robots with low programming and building complexity. One key aspect of the proposed architecture is the use of audio interfaces to control actuators and read sensors, thus allowing the usage of any device that can produce sounds as a control unit of a robot. The work also includes the development of web ba- sed programming environments that allow the usage of computers or mobile phones as control units of the robot, which can be remotely programmed and controlled. The work also includes possible applications of such low cost robotic platform, including mainly its educational usage, which was experimentally validated by teachers and students of seve- ral graduation courses. We also present an analysis of data obtained from interviews done with the students before and after the use of our platform, which confirms its acceptance as a teaching support tool

Odometria visual baseada em técnicas de structure from motion

Visual Odometry is the process that estimates camera position and orientation based solely on images and in features (projections of visual landmarks present in the scene) extraced from them. With the increasing advance of Computer Vision algorithms and computer processing power, the subarea known as Structure from Motion (SFM) started to supply mathematical tools composing localization systems for robotics and Augmented Reality applications, in contrast with its initial purpose of being used in inherently offline solutions aiming 3D reconstruction and image based modelling. In that way, this work proposes a pipeline to obtain relative position featuring a previously calibrated camera as positional sensor and based entirely on models and algorithms from SFM. Techniques usually applied in camera localization systems such as Kalman filters and particle filters are not used, making unnecessary additional information like probabilistic models for camera state transition. Experiments assessing both 3D reconstruction quality and camera position estimated by the system were performed, in which image sequences captured in reallistic scenarios were processed and compared to localization data gathered from a mobile robotic platform