1,721,049 research outputs found
Immersive vs desktop virtual reality in game based learning
No full textVirtual environments are recognized as more effective than other digital approaches for the acquisition of several abilities. This is because the brain recognizes the virtual world as real and this facilitates the transfer of the newly acquired skills to the real world. In this paper, we present a game that has been designed and developed with the aim of teaching spatial orientation abilities to teenagers with mild intellectual impairments. In particular, the game focuses on the training of two basic skills: Perspective taking and mental rotation. Perspective taking refers to the ability of imagining how the world looks like from another person's point of view, while mental rotation is the ability to mentally represent and manipulate physical objects in one's mind. The game, which takes place in a virtual environment, shows the player a scene with some objects on the table. The player has to choose among four provided alternatives, the one that shows how the scene would look like from a different side of the table. The game was first developed to be used with either a desktop pc monitor or an interactive touch table. In this case, a virtual world is represented, but the player is not completely immersed in it, he just looks at the scene from outside. A second version of the same game has then been developed using a Head Mounted Display (HMD), which makes the player feel immersed in the virtual environment, where he can freely move around just as if it was real. In this paper, we discuss both advantages and disadvantages of the immersive Virtual Reality (VR) compared to the desktop VR. In fact, on the one hand, having the possibility to "dive" into the virtual world allows the player to: Better build a mental model of the scene and the involved objects by freely moving around the table and examining the objects from all the possible perspectives; Manage by himself the amount of help needed: It is always possible, at any time of the game, to move to the other side of the table and see what the scene looks like. Increase his involvement in the game by exploring the virtual world as he pleases. Have a better learning transfer thanks to the similarities between the virtual and the real worlds. On the other hand, using a HMD can be tiring and cause sickness to some players. Furthermore, the presence of a complete environment in which to move and explore, can draw the attention away from the main task of the game and therefore influence learning negatively. Experiments are planned to verify the foreseen advantages and disadvantages involving young adults with mild intellective disabilities
Geographic Information Systems (GIS) for land planning and surveying: the case of the city of Khouribga (Morocco)
No full textGeographic Information Systems, together with remote sensing, represent today a basic tool for land management and planning and for the monitoring of the environmental critical factors of human and natural origin. Their use has been increasing in the last years also thanks to software and hardware development; therefore the use of GIS has spread not only into the field of cartography or land management and planning but also into other particular sectors among which there are the environmental and civil protection, geomarketing, social and economical analyses, agriculture, water, the exploitation of underground and overground resources, etc. All this testifies the relevance that this technologies have acquired in the more advanced countries: they give the chance of a complete integration of the available information, guaranteeing the possibility of immediate and rational decisions by assisting the operator in the data organization and in the comprehension of their mutual spatial correlations.
In this paper, after a brief introduction to the geographic information systems through the definitions of their main basic concepts, we shall describe an information system created for the monitoring and the territorial planning of the city of Khouribga (Morocco), chosen as a model for the several environmental problems it presents. In fact the city and its surroundings are characterised by the presence of an intense mining activity for phosphate minerals and of extended areas in which phosphate waste materials are accumulated. These are a source of strong degradation, pollution and landscape alteration to which the competent local authorities want to find a solution
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
UN ITINERARIO NATURALISTICO PER I MONTI DELLA CALVANA. I geositi: una risorsa da tutelare per la salvaguardia di un territorio alla periferia della città.
No full textComparing real walking in immersive virtual reality and in physical world using gait analysis
No full textOne of the main goals of immersive virtual reality is to allow people to walk in virtual environments in an ecological way. Several techniques have been developed in the literature: the use of devices such as omnidirectional treadmills, robotic tiles, stepping systems, sliding-based surfaces and human-sized hamster balls; or techniques such as the walking-in-place. Conversely, real walk requires the precise tracking of the user, performed on a large area, in order to allow him/her to explore the virtual environment without limitations. This can be achieved by using optical tracking systems, or low cost off-the shelf devices, such as the HTC-Vive tracking system. Here, we consider the latter solution and we aim to compare real walking in a virtual environment with respect to walking in a corresponding real world situation, with the long term goal of using it in rehabilitation and clinical setups. Moreover, we analyze the effect of having a virtual representation of the user’s body inside the virtual environment. Several spatio-temporal gait parameters are analyzed, such as the total distance walked, the patterns of velocity in each considered path, the velocity peaks, the step count and step length. Differently from what can be typically found in the literature, in our preliminary results we did not find significant differences between real walk in virtual environments and in a real world situation. Also having the virtual representation of the body inside virtual reality does not affect the gait parameters. The implication of these results for future research, in particular with respect to the specific considered setup, are discussed
Il sistema informativo geografico della città di Khouribga (Marocco): uso e monitoraggio del suolo attraverso immagini satellitari ad alta risoluzione IKONOS
No full textIl lavoro di implementazione del sistema informativo territoriale della città di Khouribga è stato realizzato nell’ambito della fase di diagnostica del progetto SIGEK 2000 – “amélioration des capacitès techniques et de gestion locale pour la mise en place d'un système de gestion environnementale intégrée dans la ville de Khouribga (Maroc)"-, finanziato dall’Unione Europea, di cui tale lavoro costituisce uno degli obiettivi primari . Lo scopo è stato quello di realizzare un sistema informativo della città e dei suoi dintorni da fornire agli uffici tecnici della municipalità di Khouribga. Con esso l’amministrazione comunale è stata dotata di uno strumento moderno, versatile e dinamico per la gestione territoriale e la pianificazione di tutti gli aspetti ambientali su un’area in forte sviluppo industriale ed antropico, scelta come modello a causa delle innumerevoli problematiche ambientali in essa presenti. La città ed i suoi dintorni sono infatti caratterizzati dalla presenza di una intensa attività estrattiva per minerali fosfatici e di estesi accumuli di sterile fosfatico che, oltre ad alterare il paesaggio, rappresentano una fonte di degrado e di inquinamento ambientale a cui le autorità competenti vogliono porre rimedio.
Dopo la costruzione del modello della base dati, completo dei relativi metadati, si è proceduto alla introduzione nel sistema informativo, tramite digitalizzazione a video, di un elevato numero di oggetti geografici. A questa attività sono seguite procedure di analisi, in particolare per la realizzazione del modello digitale della morfologia e degli acquiferi.
Una immagine satellitare Ikonos ad alta risoluzione è stata utilizzata per costruire, tramite interpretazione a video, una Carta dell’uso del suolo. Verifiche all’interpretazione sono state eseguite attraverso il controllo di informazioni cartografiche preesistenti e di foto aeree in stereoscopia; numerosi sopralluoghi sono stati effettuati sul territorio sia urbano che rurale per dirimere alcuni dubbi interpretativi
Autonomous learning of disparity-vergence behavior through distributed coding and population reward: Basic mechanisms and real-world conditioning on a robot stereo head
Full text linkAbstract A robotic system implementation that exhibits autonomous learning capabilities of effective control for vergence eye movements is presented. The system, directly relying on a distributed (i.e. neural) representation of binocular disparity, shows a large tolerance to the inaccuracies of real stereo heads and to the changeable environment. The proposed approach combines early binocular vision mechanisms with basic learning processes, such as synaptic plasticity and reward modulation. The computational substrate consists of a network of modeled V1 complex cells that act as oriented binocular disparity detectors. The resulting population response, besides implicit binocular depth cues about the environment, also provides a global signal (i.e. the overall activity of the population itself) to describe the state of the system and thus its deviation from the desired vergence position. The proposed network, by taking into account the modification of its internal state as a consequence of the action performed, evolves following a differential Hebbian rule. The overall activity of the population is exploited to derive an intrinsic signal that drives the weights update. Exploiting this signal implies a maximization of the population activity itself, thus providing an highly effective reward for the developing of a stable and accurate vergence behavior. The role of the different orientations in the learning process is evaluated separately against the whole population, evidencing that the interplay among the differently oriented channels allows a faster learning capability and a more accurate control. The efficacy of the proposed intrinsic reward signal is thus comparatively assessed against the ground-truth signal (the actual disparity) providing equivalent results, and thus validating the approach. Trained in a simulated environment, the proposed network, is able to cope with vergent geometry and thus to learn effective vergence movements for static and moving visual targets. Experimental tests with real robot stereo pairs demonstrate the capability of the architecture not just to directly learn from the environment, but to adapt the control to the stimulus characteristics
Importanza del coefficiente di Witmer-Desmonts nella diagnostica delle uveiti da toxoplasma gondii.
No full textGait-related frequency modulation of beta oscillatory activity in the subthalamic nucleus of parkinsonian patients
Full text linkBackground: Abnormal beta band activity in the subthalamic nucleus (STN) is known to be exaggerated in patients with Parkinson's disease, and the amplitude of such activity has been associated with akinetic rigid symptoms. New devices for deep brain stimulation (DBS) that operate by adapting the stimulation parameters generally rely on the detection of beta activity amplitude modulations in these patients. Movement-related frequency modulation of beta oscillatory activity has been poorly investigated, despite being an attractive variable for extracting information about basal ganglia activity. Objective: We studied the STN oscillatory activity associated with locomotion and proposed a new approach to extract movement related information from beta band activity. Methods: We recorded bilateral local field potential of the STN in eight parkinsonian patients implanted with DBS electrodes during upright quiet standing and unperturbed walking. Neurophysiological recordings were combined with kinematic measurements and individual molecular brain imaging studies. We then determined the information carried by the STN oscillatory activity about locomotion and we identified task-specific biomarkers. Results: We found a gait-related peak frequency modulation of the beta band of STN recordings of parkinsonian patients. This novel biomarker and the associated power modulations were highly informative to detect the walking state (with respect to standing) in each single patient. Conclusion: Frequency modulation in the human STN represents a fundamental aspect of information processing of locomotion. Our information-driven approach could significantly enrich the spectrum of Parkinson's neural markers, with input signals encoding ongoing tasks execution for an appropriate online tuning of DBS delivery
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