71 resultados para Companhia de Navegação

em Universidade Federal do Rio Grande do Norte(UFRN)


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Seted in the context of the educational actions of Casa Renascer, a non-governmental organization, located in Natal city, which had as its primary purpose the care with children and adolescent girls in vulnerable situations, this research is based on describing and analysis on the topic in the creative process developed by Asmarias Theatre Company from 1993 to 2003, a process that culminated in the assembly of the dramatic text, Mateus e Mateusa, of Qorpo-Santo. In this research is focused on the route of the Theatre Company has done so much theater in its early history (1993), with the practice of reading and dramatic writing in the preparation of didactic material called Primer of Inventions, as in the procedures with theater street and forum theater (1997 to 2000) to the reunion in 2001 of seven teenagers which articulated the last group formation next to the assembly's text Qorpo-Santo (2002- 2003). During the development on this learning, the evolution of the creative process based on institutional theme when asked if one can provide moments of educational experiences through the traditional form of theater, with reference to the issues inherent in the dramatic texts considered classics. The debate on the issue through research and analysis in its descriptions and finds in the interim between his past and present indications that lead to conclusive guises. The methodology, which is guided by research, is based in theatrical archeology (PAVIS, 2005), the evidential paradigm (GINZBURG, 1989) and the second approaches the experiences narrated by Benjamin (1985). We selected documents in formats of written texts, photographic and filmed, and identified in these files, marks and tracks which took us to understand the subject in the creative process of Asmarias Theatre Company during the tests with the dramatic text, Mateus and Mateusa, of Qorpo-Santo. In this theatrical practice, located in the field of the theater pedagogy, it appears that the actions across thematic theater in the Casa Renascer and allowed the formation of critical aesthetic perspective and personal social dimension of the subjects involved. The theme has gained a significant proportion in the theatrical activity as a guiding point of the creative process of Theatre Company, taking in the theatrical art form. In this sense, the creative process with the dramatic and classic texts won the educational dimension to address the issue in the movement of the drama as the focus of individual creation which added to the collective universe of the interactive game

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Large efforts have been maden by the scientific community on tasks involving locomotion of mobile robots. To execute this kind of task, we must develop to the robot the ability of navigation through the environment in a safe way, that is, without collisions with the objects. In order to perform this, it is necessary to implement strategies that makes possible to detect obstacles. In this work, we deal with this problem by proposing a system that is able to collect sensory information and to estimate the possibility for obstacles to occur in the mobile robot path. Stereo cameras positioned in parallel to each other in a structure coupled to the robot are employed as the main sensory device, making possible the generation of a disparity map. Code optimizations and a strategy for data reduction and abstraction are applied to the images, resulting in a substantial gain in the execution time. This makes possible to the high level decision processes to execute obstacle deviation in real time. This system can be employed in situations where the robot is remotely operated, as well as in situations where it depends only on itself to generate trajectories (the autonomous case)

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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

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This work deals with the development of a prototype of a helicopter quadrotor for monitoring applications in oil facilities. Anomaly detection problems can be resolved through monitoringmissions performed by a suitably instrumented quadrotor, i.e. infrared thermosensors should be embedded. The proposed monitoring system aims to reduce accidents as well as to make possible the use of non-destructive techniques for detection and location of leaks caused by corrosion. To this end, the implementation of a prototype, its stabilization and a navigation strategy have been proposed. The control strategy is based on dividing the problem into two control hierarchical levels: the lower level stabilizes the angles and the altitude of the vehicle at the desired values, while the higher one provide appropriate references signals to the lower level in order the quadrotor performs the desired movements. The navigation strategy for helicopter quadrotor is made using information provided by a acquisition image system (monocular camera) embedded onto the helicopter. Considering that the low-level control has been solved, the proposed vision-based navigation technique treats the problem as high level control strategies, such as, relative position control, trajectory generation and trajectory tracking. For the position control we use a control technique for visual servoing based on image features. The trajectory generation is done in a offline step, which is a visual trajectory composed of a sequence of images. For the trajectory tracking problem is proposed a control strategy by continuous servovision, thus enabling a navigation strategy without metric maps. Simulation and experimental results are presented to validate the proposal

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The main task and one of the major mobile robotics problems is its navigation process. Conceptualy, this process means drive the robot from an initial position and orientation to a goal position and orientation, along an admissible path respecting the temporal and velocity constraints. This task must be accomplished by some subtasks like robot localization in the workspace, admissible path planning, trajectory generation and motion control. Moreover, autonomous wheeled mobile robots have kinematics constraints, also called nonholonomic constraints, that impose the robot can not move everywhere freely in its workspace, reducing the number of feasible paths between two distinct positions. This work mainly approaches the path planning and trajectory generation problems applied to wheeled mobile robots acting on a robot soccer environment. The major dificulty in this process is to find a smooth function that respects the imposed robot kinematic constraints. This work proposes a path generation strategy based on parametric polynomials of third degree for the 'x' and 'y' axis. The 'theta' orientation is derived from the 'y' and 'x' relations in such a way that the generated path respects the kinematic constraint. To execute the trajectory, this work also shows a simple control strategy acting on the robot linear and angular velocities

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The incorporation of computing in class instigate the use of the Internet and websites as a content support in the teaching/leaning process. This kind of practice had challenged the students to read through eletronic hypertextual means. In that way, we re trying to undestand which strategies of reading and navigation the students of the second and third grade of highschool levels are using when reading electronic hypertexts from the www.ambientebrasil.com.br website. The research took place in the Escola Estadual Jerônimo Rosado in Mossoró RN. Our theoretical base was estructured on the digital Technology (electronic hypertext estructure and it s navigation modes), in applied linguistics (act of reading) and in cognition (interaction of the reader with the text and the use of reading strategies in the virtual computing enviroment). The applied methodology was the case analysis which was developed with the reunion of collected data through qualitative reseach questionaries, direct observations and video recording sessions. The research demonstrates that reader s ability in the act of navigating on virtual sites activates his/her reading strategies. Also shows how the semantic architecture of the hyperlinks can interfere directly over the strategies of reading and navigation in specific websites. Our research also intend to demonstrate that the student use his strategies of linear text reading when are not accustomed to use the reading through websites in a regular basis. The investigation concludes observing that the amount of hypertexts per pages and the inappropriate use of the multimedia elements were harmful to the reading fluency

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Panoramic rendering is the visualization of three-dimensional objects in a virtual environment through a wide viewing angle. This work investigated if the use of panoramas is able to promote faster searches in a virtual environment. Panoramas allow the presentation of space through less need to change the orientation of the camera, especially for the case of projections spanning 360º surrounding the user, which can benefit searching. However, the larger the angle, more distorted is the visualization of the environment, causing confusion in navigation. The distortion is even bigger when the user changes the pitch of the camera, by looking up or down. In this work we developed a technique to eliminate specifically the distortions caused by changes in pitch, which was called hemispheric projection. Experiments were done to evaluate the performance of search navigation through perspective, cylindrical and hemispherical projections. The results indicate that navigating with perspective projection is superior than navigating with panoramic projections, possibly due to factors such as (i) lack of experience of the participants in understanding the scenes displayed as panoramas, (ii) the inherent presence of distortion in panoramic projections and (iii) a lower display resolution because the objects are presented in smaller sizes in panoramic projections, making the perception of details more difficult. However, the hemispherical projection was better than the cylindrical, indicating that the developed technique provides benefits for navigation compared to current techniques of panoramic projection. The hemispheric projection also provided the least amount of changes of camera orientation, which is an indication that the hemispheric projections may be particularly useful in situations where there are restrictions on the ease to change the orientation. Future research will investigate the performance of cameras interactions on slower devices, such as using only keyboard, or brain-machine interfaces

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This work presents a proposal to build a Mathematics Teaching Laboratory (MTL) whose main theme is the study, construction and use of instruments for navigation and location of mathematical content in an interdisciplinary way approach, and develop a notebook of activities focused on navigational instruments. For this it was necessary a literature review to understand the different conceptions of MTL and its pedagogical implications. The methodology used was literature research, construction and handling of instruments, and pedagogical experimentation. Lorenzato (2006) highlights the importance of an environment and suitable for a professional who can do a good job instruments. The implementation of an LEM can find some obstacles. The lack of support from other teachers or the management, the lack of a suitable place to store the materials produced, the lack of time in the workload of the teacher to prepare the lab activity, etc. Even in unfavorable or adverse conditions, according Lorenzato (2006), its implementation will benefit teachers and students. The lack of teacher training in their initial and continuing education, to use materials, and the lack of manuals with lab activities are also mentioned as factors that keep teachers from MTL. With propóposito assist the teacher of elementary or middle school in building a theme MTL prepared and we are providing a notebook of activities that provides a didactic sequence involving History and Mathematics. The book consists of four accompanied by suggestions for teachers activities, however the teacher has full autonomy to adapt the activities to the reality of your school. Among the instruments of navigation presented in this study chose to build the quadrant due to its simplicity, low cost of material and great teaching potential that this instrument has. But a theme lab is always being built and rebuilt as it is a research environment

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Navigation, in both virtual and real environments, is the process of a deliberated movement to a specific place that is usually away from the origin point, and that cannot be perceived from it. Navigation aid techniques (TANs) have as their main objective help finding a path through a virtual environment to a desired location and, are widely used because they ease the navigation on these unknown environments. Tools like maps, GPS (Global Positioning System) or even oral instructions are real world examples of TAN usage. Most of the works which propose new TANs for virtual environments aim to analyze their impact in efficiency gain on navigation tasks from a known place to an unknown place. However, such papers tend to ignore the effect caused by a TAN usage over the route knowledge acquisition process, which is important on virtual to real training transfer, for example. Based on a user study, it was possible to confirm that TANs with different strategies affects the performance of search tasks differently and that the efficiency of the help provided by a TAN is not inversely related to the cognitive load of the technique’s aids. A technique classification formula was created. This formula utilizes three factors instead of only efficiency. The experiment’s data were applied to the formula and we obtained a better refinement of help level provided by TANs.

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Oil exploration at great depths requires the use of mobile robots to perform various operations such as maintenance, assembly etc. In this context, the trajectory planning and navigation study of these robots is relevant, as the great challenge is to navigate in an environment that is not fully known. The main objective is to develop a navigation algorithm to plan the path of a mobile robot that is in a given position (

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Oil exploration at great depths requires the use of mobile robots to perform various operations such as maintenance, assembly etc. In this context, the trajectory planning and navigation study of these robots is relevant, as the great challenge is to navigate in an environment that is not fully known. The main objective is to develop a navigation algorithm to plan the path of a mobile robot that is in a given position (

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This work proposes a new autonomous navigation strategy assisted by genetic algorithm with dynamic planning for terrestrial mobile robots, called DPNA-GA (Dynamic Planning Navigation Algorithm optimized with Genetic Algorithm). The strategy was applied in environments - both static and dynamic - in which the location and shape of the obstacles is not known in advance. In each shift event, a control algorithm minimizes the distance between the robot and the object and maximizes the distance from the obstacles, rescheduling the route. Using a spatial location sensor and a set of distance sensors, the proposed navigation strategy is able to dynamically plan optimal collision-free paths. Simulations performed in different environments demonstrated that the technique provides a high degree of flexibility and robustness. For this, there were applied several variations of genetic parameters such as: crossing rate, population size, among others. Finally, the simulation results successfully demonstrate the effectiveness and robustness of DPNA-GA technique, validating it for real applications in terrestrial mobile robots.

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This work proposes a new autonomous navigation strategy assisted by genetic algorithm with dynamic planning for terrestrial mobile robots, called DPNA-GA (Dynamic Planning Navigation Algorithm optimized with Genetic Algorithm). The strategy was applied in environments - both static and dynamic - in which the location and shape of the obstacles is not known in advance. In each shift event, a control algorithm minimizes the distance between the robot and the object and maximizes the distance from the obstacles, rescheduling the route. Using a spatial location sensor and a set of distance sensors, the proposed navigation strategy is able to dynamically plan optimal collision-free paths. Simulations performed in different environments demonstrated that the technique provides a high degree of flexibility and robustness. For this, there were applied several variations of genetic parameters such as: crossing rate, population size, among others. Finally, the simulation results successfully demonstrate the effectiveness and robustness of DPNA-GA technique, validating it for real applications in terrestrial mobile robots.

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Seted in the context of the educational actions of Casa Renascer, a non-governmental organization, located in Natal city, which had as its primary purpose the care with children and adolescent girls in vulnerable situations, this research is based on describing and analysis on the topic in the creative process developed by Asmarias Theatre Company from 1993 to 2003, a process that culminated in the assembly of the dramatic text, Mateus e Mateusa, of Qorpo-Santo. In this research is focused on the route of the Theatre Company has done so much theater in its early history (1993), with the practice of reading and dramatic writing in the preparation of didactic material called Primer of Inventions, as in the procedures with theater street and forum theater (1997 to 2000) to the reunion in 2001 of seven teenagers which articulated the last group formation next to the assembly's text Qorpo-Santo (2002- 2003). During the development on this learning, the evolution of the creative process based on institutional theme when asked if one can provide moments of educational experiences through the traditional form of theater, with reference to the issues inherent in the dramatic texts considered classics. The debate on the issue through research and analysis in its descriptions and finds in the interim between his past and present indications that lead to conclusive guises. The methodology, which is guided by research, is based in theatrical archeology (PAVIS, 2005), the evidential paradigm (GINZBURG, 1989) and the second approaches the experiences narrated by Benjamin (1985). We selected documents in formats of written texts, photographic and filmed, and identified in these files, marks and tracks which took us to understand the subject in the creative process of Asmarias Theatre Company during the tests with the dramatic text, Mateus and Mateusa, of Qorpo-Santo. In this theatrical practice, located in the field of the theater pedagogy, it appears that the actions across thematic theater in the Casa Renascer and allowed the formation of critical aesthetic perspective and personal social dimension of the subjects involved. The theme has gained a significant proportion in the theatrical activity as a guiding point of the creative process of Theatre Company, taking in the theatrical art form. In this sense, the creative process with the dramatic and classic texts won the educational dimension to address the issue in the movement of the drama as the focus of individual creation which added to the collective universe of the interactive game

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Algumas pesquisas demonstram que a presença de um parceiro social durante uma situação de risco modula a resposta ao estresse, atenuando seus efeitos negativos. Neste estudo, 8 díades de machos e 8 de fêmeas de sagüi comum (Callithrix jacchus) foram expostos a um ambiente novo, sozinhos e acompanhados de um parceiro de mesmo sexo e idade. Quando submetidos a um ambiente novo em companhia de um animal de mesmo sexo, os machos apresentaram um perfil mais filiativo enquanto as fêmeas foram mais competitivas entre si. Os resultados mostram que a resposta comportamental é sexualmente dimórfica, e que machos e fêmeas utilizam diferentes estratégias quando confrontados com situações desafiadoras no ambiente natural Abstract Some researches demonstrate that the presence of a social partner during a challenging situation modulates the stress response, decreasing its negative effects. In this study common marmoset (Callithrix jacchus) males and females were exposed to a new environment, alone or in companion of a social partner of the same sex and age. When submitted to new environment in companion of a same-sex social partner males showed more affiliation whereas females performed agonistic behaviors. The results show that behavioral response is sexually dimorphic and that males and females used different strategies when facing challenging situations in natural conditions