Virtual simulator for mobile robots navigation systems

This paper presents the virtual environment implementation for project simulation and conception of supervision and control systems for mobile robots, that are capable to operate and adapting in different environments and conditions. This virtual system has as purpose to facilitate the development of embedded architecture systems, emphasizing the implementation of tools that allow the simulation of the kinematic conditions, dynamic and control, with real time monitoring of all important system points. For this, an open control architecture is proposal, integrating the two main techniques of robotic control implementation in the hardware level: systems microprocessors and reconfigurable hardware devices. The implemented simulator system is composed of a trajectory generating module, a kinematic and dynamic simulator module and of a analysis module of results and errors. All the kinematic and dynamic results shown during the simulation can be evaluated and visualized in graphs and tables formats, in the results analysis module, allowing an improvement in the system, minimizing the errors with the necessary adjustments optimization. For controller implementation in the embedded system, it uses the rapid prototyping, that is the technology that allows, in set with the virtual simulation environment, the development of a controller project for mobile robots. The validation and tests had been accomplish with nonholonomics mobile robots models with diferencial transmission. © 2008 IEEE.

Sistema gerador de apoio a um dicionário temático visual-gestual baseado em realidade virtual

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Elaboração e avaliação de um ambiente virtual para o ensino/aprendizagem de embriologia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

SIMPLARCOM: simulador para planejamento de redes de comunicação sem fio utilizando realidade virtual e modelos de propagação

Este simulador é formado pela junção de técnicas de Realidade Virtual com modelos de propagação, desenvolvidos através dos estudos de rádio enlace, que descrevem a perda que o sinal transmitido sofre ao longo do percurso no ambiente. O simulador possui dois módulos. O primeiro permite a criação do ambiente virtual com o posicionamento, sobre um terreno, de prédios, árvores, carros, antenas e outras primitivas que permitem a construção de um ambiente tridimensional customizável. O segundo módulo permite a configuração dos parâmetros relacionados a propagação de sinal de antenas como a potência, a frequência, o ganho, etc., e também selecionar o modelo de propagação para a execução da simulação. Dentro deste segundo módulo, existe um submódulo responsável pelo estudo do planejamento da área de cobertura composta pelas antenas, em outras palavras, este submódulo simula a distância que cada antena no cenário consegue atingir e gera a respectiva área de cobertura. Para demonstrar a eficiência do simulador foram criados dois ambientes virtuais para testes. Um cenário representando um ambiente urbano onde empregou-se um modelo de propagação clássico, Okumura-Hata para cidades pequenas e médias, e um ambiente tridimensional arborizado utilizando um modelo especifico para simulação de propagação para regiões densamente arborizadas, desenvolvido na Universidade Federal do Pará chamado de Lyra-Castro-UFPA.

O processo de formação permanente em serviço e em exercício de formadores para a docência virtual

Pós-graduação em Educação - FCT

Procedimentos de jogadores no jogo virtual Colheita Feliz: a virtude e a regra

This study based on moral culture research and the theoretical Piagetian perspective aims to investigate the relation between virtue and rules in the procedures of participants in the Internet game Colheita Feliz (Happy Harvest) – an Orkut application. By means of descriptive qualitative analysis, the behavior of 60 participants in the game was observed during two months. The participants’ performance ranking was analyzed according to the procedures they used. The results showed predominance of the crop stealing procedure in comparison with the crop cultivation procedure and allowed to consider that the action of stealing of the participants was not guided by the universal principles of virtue, honesty or lack of it (moral domain) but by the playing convention for the game (social domain) favoring the stealing procedure, and also by personal domain (choices) and mutual agreement among the subjects participating in the game. The data did not indicate connections between the participants’ actions inside and outside virtual and real fields with regard to stealing, and reinforced the idea that rules are conventionalized in the domain of a group and depend on social interactions by which mutual respect among peers must prevail. The data also shows that morality is not the regulatory actions in the game. The results also showed the importance of carrying out research on procedures used by computer game players since such procedures can demonstrate cognitive, moral, affective and social aspects perceived during playful interaction situations.

Espaço virtual de um grupo de pesquisa: o olhar dos tutores

O Grupo de Estudos e Pesquisas de Tecnologia da Informação nos Processos de Trabalho em Enfermagem (GEPETE) visa produzir e socializar o conhecimento na área de tecnologia da informação e comunicação na saúde e enfermagem, articular a integração com grupos de pesquisas desta área e propiciar a participação de alunos. O estudo realizado pelos tutores teve como objetivo relatar a construção do ambiente virtual de aprendizagem (AVA) e a experiência dos tutores como mediadores de um grupo de pesquisa na plataforma Moodle. Para tanto, foi construído um AVA, realizada a mediação pedagógica sob a temática tutoria e o diagnóstico inicial em relação às dificuldades na utilização da tecnologia na interatividade e na comunicação, o que permitiu a proposição da continuidade da utilização da plataforma como um recurso para apoiar as atividades de pesquisa, oferecer aos líderes pesquisadores mecanismos para socialização dos projetos e possibilidades de orientação à distância.

Virtual sensing technology applied to a swarm of autonomous robots.

This thesis proposes a novel technology in the field of swarm robotics that allows a swarm of robots to sense a virtual environment through virtual sensors. Virtual sensing is a desirable and helpful technology in swarm robotics research activity, because it allows the researchers to efficiently and quickly perform experiments otherwise more expensive and time consuming, or even impossible. In particular, we envision two useful applications for virtual sensing technology. On the one hand, it is possible to prototype and foresee the effects of a new sensor on a robot swarm, before producing it. On the other hand, thanks to this technology it is possible to study the behaviour of robots operating in environments that are not easily reproducible inside a lab for safety reasons or just because physically infeasible. The use of virtual sensing technology for sensor prototyping aims to foresee the behaviour of the swarm enhanced with new or more powerful sensors, without producing the hardware. Sensor prototyping can be used to tune a new sensor or perform performance comparison tests between alternative types of sensors. This kind of prototyping experiments can be performed through the presented tool, that allows to rapidly develop and test software virtual sensors of different typologies and quality, emulating the behaviour of several hardware real sensors. By investigating on which sensors is better to invest, a researcher can minimize the sensors’ production cost while achieving a given swarm performance. Through augmented reality, it is possible to test the performance of the swarm in a desired virtual environment that cannot be set into the lab for physical, logistic or economical reasons. The virtual environment is sensed by the robots through properly designed virtual sensors. Virtual sensing technology allows a researcher to quickly carry out real robots experiment in challenging scenarios without all the required hardware and environment.

Real Walking through Virtual Environments by Redirection Techniques

We present redirection techniques that support exploration of large-scale virtual environments (VEs) by means of real walking. We quantify to what degree users can unknowingly be redirected in order to guide them through VEs in which virtual paths differ from the physical paths. We further introduce the concept of dynamic passive haptics by which any number of virtual objects can be mapped to real physical proxy props having similar haptic properties (i. e., size, shape, and surface structure), such that the user can sense these virtual objects by touching their real world counterparts. Dynamic passive haptics provides the user with the illusion of interacting with a desired virtual object by redirecting her to the corresponding proxy prop. We describe the concepts of generic redirected walking and dynamic passive haptics and present experiments in which we have evaluated these concepts. Furthermore, we discuss implications that have been derived from a user study, and we present approaches that derive physical paths which may vary from the virtual counterparts.

3-D Audio in Mobile Communication Devices: Effects of Self-Created and External Sounds on Presence in Auditory Virtual Environments

This article describes a series of experiments which were carried out to measure the sense of presence in auditory virtual environments. Within the study a comparison of self-created signals to signals created by the surrounding environment is drawn. Furthermore, it is investigated if the room characteristics of the simulated environment have consequences on the perception of presence during vocalization or when listening to speech. Finally the experiments give information about the influence of background signals on the sense of presence. In the experiments subjects rated the degree of perceived presence in an auditory virtual environment on a perceptual scale. It is described which parameters have the most influence on the perception of presence and which ones are of minor influence. The results show that on the one hand an external speaker has more influence on the sense of presence than an adequate presentation of one’s own voice. On the other hand both room reflections and adequately presented background signals significantly increase the perceived presence in the virtual environment.

Language Learning in 3D Virtual World

Second Life (SL) is an ideal platform for language learning. It is called a Multi-User Virtual Environment, where users can have varieties of learning experiences in life-like environments. Numerous attempts have been made to use SL as a platform for language teaching and the possibility of SL as a means to promote conversational interactions has been reported. However, the research so far has largely focused on simply using SL without further augmentations for communication between learners or between teachers and learners in a school-like environment. Conversely, not enough attention has been paid to its controllability which builds on the embedded functions in SL. This study, based on the latest theories of second language acquisition, especially on the Task Based Language Teaching and the Interaction Hypothesis, proposes to design and implement an automatized interactive task space (AITS) where robotic agents work as interlocutors of learners. This paper presents a design that incorporates the SLA theories into SL and the implementation method of the design to construct AITS, fulfilling the controllability of SL. It also presents the result of the evaluation experiment conducted on the constructed AITS.

Considering Stage Direction as Building Informed Virtual Environments

This article begins with some recent considerations about real-time music, inspired by the latest contribution of French composer Philippe Manoury. Then, through the case study of the scenic performance La Traversée de la nuit, we analyse some perspectives for designing an Informed Virtual Environment dedicated to live show artistic domain.

Influence of Information and Instructions on Human Behavior in Tunnel Accidents: A Virtual Reality Study

Human behavior is a major factor modulating the consequences of road tunnel accidents. We investigated the effect of information and instruction on drivers' behavior as well as the usability of virtual environments to simulate such emergency situations. Tunnel safety knowledge of the general population was assessed using an online questionnaire, and tunnel safety behavior was investigated in a virtual reality experiment. Forty-four participants completed three drives through a virtual road tunnel and were confronted with a traffic jam, no event, and an accident blocking the road. Participants were randomly assigned to a control group (no intervention), an informed group who read a brochure containing safety information prior to the tunnel drives, or an informed and instructed group who read the same brochure and received additional instructions during the emergency situation. Informed participants showed better and quicker safety behavior than the control group. Self-reports of anxiety were assessed three times during each drive. Anxiety was elevated during and after the emergency situation. The findings demonstrate problematic safety behavior in the control group and that knowledge of safety information fosters adequate behavior in tunnel emergencies. Enhanced anxiety ratings during the emergency situation indicate external validity of the virtual environment.

Ecological validity of virtual reality daily living activities screening for early dementia: longitudinal study

Background: Dementia is a multifaceted disorder that impairs cognitive functions, such as memory, language, and executive functions necessary to plan, organize, and prioritize tasks required for goal-directed behaviors. In most cases, individuals with dementia experience difficulties interacting with physical and social environments. The purpose of this study was to establish ecological validity and initial construct validity of a fire evacuation Virtual Reality Day-Out Task (VR-DOT) environment based on performance profiles as a screening tool for early dementia. Objective: The objectives were (1) to examine the relationships among the performances of 3 groups of participants in the VR-DOT and traditional neuropsychological tests employed to assess executive functions, and (2) to compare the performance of participants with mild Alzheimer’s-type dementia (AD) to those with amnestic single-domain mild cognitive impairment (MCI) and healthy controls in the VR-DOT and traditional neuropsychological tests used to assess executive functions. We hypothesized that the 2 cognitively impaired groups would have distinct performance profiles and show significantly impaired independent functioning in ADL compared to the healthy controls. Methods: The study population included 3 groups: 72 healthy control elderly participants, 65 amnestic MCI participants, and 68 mild AD participants. A natural user interface framework based on a fire evacuation VR-DOT environment was used for assessing physical and cognitive abilities of seniors over 3 years. VR-DOT focuses on the subtle errors and patterns in performing everyday activities and has the advantage of not depending on a subjective rating of an individual person. We further assessed functional capacity by both neuropsychological tests (including measures of attention, memory, working memory, executive functions, language, and depression). We also evaluated performance in finger tapping, grip strength, stride length, gait speed, and chair stands separately and while performing VR-DOTs in order to correlate performance in these measures with VR-DOTs because performance while navigating a virtual environment is a valid and reliable indicator of cognitive decline in elderly persons. Results: The mild AD group was more impaired than the amnestic MCI group, and both were more impaired than healthy controls. The novel VR-DOT functional index correlated strongly with standard cognitive and functional measurements, such as mini-mental state examination (MMSE; rho=0.26, P=.01) and Bristol Activities of Daily Living (ADL) scale scores (rho=0.32, P=.001). Conclusions: Functional impairment is a defining characteristic of predementia and is partly dependent on the degree of cognitive impairment. The novel virtual reality measures of functional ability seem more sensitive to functional impairment than qualitative measures in predementia, thus accurately differentiating from healthy controls. We conclude that VR-DOT is an effective tool for discriminating predementia and mild AD from controls by detecting differences in terms of errors, omissions, and perseverations while measuring ADL functional ability.

Adaptive fuzzy knowledge-based systems for control metabots' mobility on virtual environments

The confluence of three-dimensional (3D) virtual worlds with social networks imposes on software agents, in addition to conversational functions, the same behaviours as those common to human-driven avatars. In this paper, we explore the possibilities of the use of metabots (metaverse robots) with motion capabilities in complex virtual 3D worlds and we put forward a learning model based on the techniques used in evolutionary computation for optimizing the fuzzy controllers which will subsequently be used by metabots for moving around a virtual environment.