994 resultados para VISUAL GUIDANCE
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This study evaluates the influence of different cartographic representations of in-car navigation systems on visual demand, subjective preference, and navigational error. It takes into account the type and complexity of the representation, maneuvering complexity, road layout, and driver gender. A group of 28 drivers (14 male and 14 female) participated in this experiment which was performed in a low-cost driving simulator. The tests were performed on a limited number of instances for each type of representation, and their purpose was to carry out a preliminary assessment and provide future avenues for further studies. Data collected for the visual demand study were analyzed using non-parametric statistical analyses. Results confirmed previous research that showed that different levels of design complexity significantly influence visual demand. Non-grid-like road networks, for example, influence significantly visual demand and navigational error. An analysis of simple maneuvers on a grid-like road network showed that static and blinking arrows did not present significant differences. From the set of representations analyzed to assess visual demand, both arrows were equally efficient. From a gender perspective, women seem to took at the display more than men, but this factor was not significant. With respect to subjective preferences, drivers prefer representations with mimetic landmarks when they perform straight-ahead tasks. For maneuvering tasks, landmarks in a perspective model created higher visual demands.
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This work investigates the gender effect on visual demand of drivers for dynamic maps at different cartographic scales presented In-Vehicle Route Guidance and Navigation System (RGNS). A group of 52 subjects (26 males and 26 females) took part in an experiment performed in a low-cost driving simulator. the driver's task consisted of navigating in an unknown route using a RGNS prototype which presents maps at two different cartographic scales. This paper replicates the known phenomenon of significant relationships between gender and performance at visual-spatial tasks issue. Our results show that drivers of different genders present distinct levels of visual demand both due to the cartographic scales and maneuver complexity variation. These discussed results are based upon individual differences in terms of spatial ability and spatial anxiety.
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The role of low-level stimulus-driven control in the guidance of overt visual attention has been difficult to establish because low- and high-level visual content are spatially correlated within natural visual stimuli. Here we show that impairment of parietal cortical areas, either permanently by a lesion or reversibly by repetitive transcranial magnetic stimulation (rTMS), leads to fixation of locations with higher values of low-level features as compared to control subjects or in a no-rTMS condition. Moreover, this unmasking of stimulus-driven control crucially depends on the intrahemispheric balance between top-down and bottom-up cortical areas. This result suggests that although in normal behavior high-level features might exert a strong influence, low-level features do contribute to guide visual selection during the exploration of complex natural stimuli.
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Objectives: In alveolar distraction, in cases of severe atrophy in particular, it is often difficult to perform osteotomies in order to make a transport segment in optimal size and shape. Moreover care must be taken, not to damage the closely locating anato- mical structures such as the maxillary sinus, the inferior alveolar nerve, and the roots of the neighboring teeth. For setting ideal osteotomy lines exactly, we have developed a CT-based preoperative planning tool. Methods: 3-dimensional visual reconstruction of the jaw is created from the preoperative CT scans (1.0-mm slice thick- ness). Using the image-processing software Mimics (Materialise, Yokohama, Japan), various procedures of virtual cutting are simulated first to determine optimal osteotomy lines and to design an ideal transport segment. After the computer planning, data from the virtual solid model are transferred to a rapid prototype model, and a guiding splint is made to transfer the planned surgical simulation to the actual surgery. Results: The method was used in a case of severe atrophy of the anterior maxilla. The patient had a large maxillary sinus requir- ing a precise osteotomy in this critical area. Using the splint allowing a 3-dimensional guidance, alveolar osteotomies were easily done to achieve a transport segment in sufficient dimen- sion as planned, and any perforation of the maxillary sinus could be avoided. Finally the alveolar distraction of 10mm has suc- cessfully been performed. Conclusion: The preoperative planning method and the guiding splint described here are useful in problematic cases requiring an extremely precise osteotomy due to lack of bony space.
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Este trabajo está dirigido a indagar los factores asociados a las elecciones que realizan los sujetos con Necesidades Educativas Especiales derivadas de la Discapacidad Visual en la etapa de transición entre la escolaridad secundaria y las posibilidades de proseguir estudios superiores. Para este fin, se ha tomado en consideración que la Orientación Vocacional Ocupacional y la transición hacia la vida adulta adquieren características específicas en el caso de jóvenes que presentan Discapacidad Visual, particularmente en relación con la preparación para la continuación de estudios superiores. El interés de este trabajo reside en poder esclarecer la existencia de factores que facilitan u obstaculizan ese tránsito, a partir de la observación de sujetos disminuidos visuales y ciegos que finalizan sus estudios secundarios. Se trata de un tema que ha ocasionado interés y preocupación acerca de las estrategias a seguir para garantizar un ingreso y permanencia exitosos en los estudios superiores elegidos. Sin embargo, si se desconocen o más bien se carece de evidencia acerca de los factores a los que obedece el fenómeno descripto, es difícil poder diseñar estrategias de intervención que resulten adecuadas. Con el fin de tomar conocimiento sobre las problemáticas específicas de los jóvenes que finalizan sus estudios secundarios y que presentan Discapacidad Visual, se eligió una escuela especial de referencia en la mencionada discapacidad y se seleccionaron en ella los alumnos que participaron de este proyecto
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Este trabajo está dirigido a indagar los factores asociados a las elecciones que realizan los sujetos con Necesidades Educativas Especiales derivadas de la Discapacidad Visual en la etapa de transición entre la escolaridad secundaria y las posibilidades de proseguir estudios superiores. Para este fin, se ha tomado en consideración que la Orientación Vocacional Ocupacional y la transición hacia la vida adulta adquieren características específicas en el caso de jóvenes que presentan Discapacidad Visual, particularmente en relación con la preparación para la continuación de estudios superiores. El interés de este trabajo reside en poder esclarecer la existencia de factores que facilitan u obstaculizan ese tránsito, a partir de la observación de sujetos disminuidos visuales y ciegos que finalizan sus estudios secundarios. Se trata de un tema que ha ocasionado interés y preocupación acerca de las estrategias a seguir para garantizar un ingreso y permanencia exitosos en los estudios superiores elegidos. Sin embargo, si se desconocen o más bien se carece de evidencia acerca de los factores a los que obedece el fenómeno descripto, es difícil poder diseñar estrategias de intervención que resulten adecuadas. Con el fin de tomar conocimiento sobre las problemáticas específicas de los jóvenes que finalizan sus estudios secundarios y que presentan Discapacidad Visual, se eligió una escuela especial de referencia en la mencionada discapacidad y se seleccionaron en ella los alumnos que participaron de este proyecto
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Este trabajo está dirigido a indagar los factores asociados a las elecciones que realizan los sujetos con Necesidades Educativas Especiales derivadas de la Discapacidad Visual en la etapa de transición entre la escolaridad secundaria y las posibilidades de proseguir estudios superiores. Para este fin, se ha tomado en consideración que la Orientación Vocacional Ocupacional y la transición hacia la vida adulta adquieren características específicas en el caso de jóvenes que presentan Discapacidad Visual, particularmente en relación con la preparación para la continuación de estudios superiores. El interés de este trabajo reside en poder esclarecer la existencia de factores que facilitan u obstaculizan ese tránsito, a partir de la observación de sujetos disminuidos visuales y ciegos que finalizan sus estudios secundarios. Se trata de un tema que ha ocasionado interés y preocupación acerca de las estrategias a seguir para garantizar un ingreso y permanencia exitosos en los estudios superiores elegidos. Sin embargo, si se desconocen o más bien se carece de evidencia acerca de los factores a los que obedece el fenómeno descripto, es difícil poder diseñar estrategias de intervención que resulten adecuadas. Con el fin de tomar conocimiento sobre las problemáticas específicas de los jóvenes que finalizan sus estudios secundarios y que presentan Discapacidad Visual, se eligió una escuela especial de referencia en la mencionada discapacidad y se seleccionaron en ella los alumnos que participaron de este proyecto
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Image Based Visual Servoing (IBVS) is a robotic control scheme based on vision. This scheme uses only the visual information obtained from a camera to guide a robot from any robot pose to a desired one. However, IBVS requires the estimation of different parameters that cannot be obtained directly from the image. These parameters range from the intrinsic camera parameters (which can be obtained from a previous camera calibration), to the measured distance on the optical axis between the camera and visual features, it is the depth. This paper presents a comparative study of the performance of D-IBVS estimating the depth from three different ways using a low cost RGB-D sensor like Kinect. The visual servoing system has been developed over ROS (Robot Operating System), which is a meta-operating system for robots. The experiments prove that the computation of the depth value for each visual feature improves the system performance.
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This paper presents a new framework based on optimal control to define new dynamic visual controllers to carry out the guidance of any serial link structure. The proposed general method employs optimal control to obtain the desired behaviour in the joint space based on an indicated cost function which determines how the control effort is distributed over the joints. The proposed approach allows the development of new direct visual controllers for any mechanical joint system with redundancy. Finally, authors show experimental results and verifications on a real robotic system for some derived controllers obtained from the control framework.
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Traditional visual servoing systems do not deal with the topic of moving objects tracking. When these systems are employed to track a moving object, depending on the object velocity, visual features can go out of the image, causing the fail of the tracking task. This occurs specially when the object and the robot are both stopped and then the object starts the movement. In this work, we have employed a retina camera based on Address Event Representation (AER) in order to use events as input in the visual servoing system. The events launched by the camera indicate a pixel movement. Event visual information is processed only at the moment it occurs, reducing the response time of visual servoing systems when they are used to track moving objects.
Control and Guidance of Low-Cost Robots via Gesture Perception for Monitoring Activities in the Home
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This paper describes the development of a low-cost mini-robot that is controlled by visual gestures. The prototype allows a person with disabilities to perform visual inspections indoors and in domestic spaces. Such a device could be used as the operator's eyes obviating the need for him to move about. The robot is equipped with a motorised webcam that is also controlled by visual gestures. This camera is used to monitor tasks in the home using the mini-robot while the operator remains quiet and motionless. The prototype was evaluated through several experiments testing the ability to use the mini-robot’s kinematics and communication systems to make it follow certain paths. The mini-robot can be programmed with specific orders and can be tele-operated by means of 3D hand gestures to enable the operator to perform movements and monitor tasks from a distance.
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A replacement for, rather than an addition to, the bibliographies of the former National Organization for Public Health Nursing, the National League of Nursing Education, 1952, and the National League for Nursing, 1954-55.
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Vol. 5 issued by the National League for Nursing, Division of Nursing Education.
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The human brain assembles an incredible network of over a billion neurons. Understanding how these connections form during development in order for the brain to function properly is a fundamental question in biology. Much of this wiring takes place during embryonic development. Neurons are generated in the ventricular zone, migrate out, and begin to differentiate. However, neurons are often born in locations some distance from the target cells with which they will ultimately form connections. To form connections, neurons project long axons tipped with a specialized sensing device called a growth cone. The growing axons interact directly with molecules within the environment through which they grow. In order to find their targets, axonal growth cones use guidance molecules that can either attract or repel them. Understanding what these guidance cues are, where they are expressed, and how the growth cone is able to transduce their signal in a directionally specific manner is essential to understanding how the functional brain is constructed. In this chapter, we review what is known about the mechanisms involved in axonal guidance. We discuss how the growth cone is able to sense and respond to its environment and how it is guided by pioneering cells and axons. As examples, we discuss current models for the development of the spinal cord, the cerebral cortex, and the visual and olfactory systems. (c) 2005, Elsevier Inc.
Memory-Based Attentional Guidance: A Window to the Relationship between Working Memory and Attention
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Attention, the cognitive means by which we prioritize the processing of a subset of information, is necessary for operating efficiently and effectively in the world. Thus, a critical theoretical question is how information is selected. In the visual domain, working memory (WM)—which refers to the short-term maintenance and manipulation of information that is no longer accessible by the senses—has been highlighted as an important determinant of what is selected by visual attention. Furthermore, although WM and attention have traditionally been conceived as separate cognitive constructs, an abundance of behavioral and neural evidence indicates that these two domains are in fact intertwined and overlapping. The aim of this dissertation is to better understand the nature of WM and attention, primarily through the phenomenon of memory-based attentional guidance, whereby the active maintenance of items in visual WM reliably biases the deployment of attention to memory-matching items in the visual environment. The research presented here employs a combination of behavioral, functional imaging, and computational modeling techniques that address: (1) WM guidance effects with respect to the traditional dichotomy of top-down versus bottom-up attentional control; (2) under what circumstances the contents of WM impact visual attention; and (3) the broader hypothesis of a predictive and competitive interaction between WM and attention. Collectively, these empirical findings reveal the importance of WM as a distinct factor in attentional control and support current models of multiple-state WM, which may have broader implications for how we select and maintain information.