1,720,977 research outputs found
Enabling Context Awareness through Distributed Query Processing in Wireless Sensor Networks
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Automatic virtual Calibration of Range-Based Indoor Localization Systems
No full textThe localization methods based on received signal strength indicator (RSSI) link the RSSI values to the position of the mobile to be located. In the RSSI localization techniques based on propagation models, the accuracy depends on the tuning of the propagation models parameters. In indoor wireless networks, the propagation conditions are hardly predictable due to the dynamic nature of the RSSI, and consequently the parameters of the propagation model may change. In this paper, we present an automatic virtual calibration method of the propagation model that does not require human intervention; therefore, can be periodically performed, following the wireless channel conditions. We also propose a novel RSSI-based localization algorithm that selects the RSSI values according to their strength, and uses a calibrated propagation model to transform these values into distances, in order to estimate the position of the mobile
Design Guidelines for an Interactive 3D Model as a Supporting Tool for Exploring a Cultural Site by Visually Impaired and Sighted People
Full text linkBeing able to explore and familiarise themselves with the structure and details of a cultural site before actually visiting it is fundamental for orienting visually impaired people during the visit; otherwise, it is particularly difficult to gain a global understanding of the structure and an overall impression of a square, a church, or a large monument. Our project addressed this problem by using low cost 3D models combined with audio descriptions to enable visually impaired users to explore the cultural site autonomously. Audio descriptions are organised into three groups (for historical, practical, and architectural information), and for each group, several tracks are recorded giving increasing levels of details. Users can easily navigate through the audio tracks to follow their tactile exploration by listening to the information they are most interested in. Relevant details are reproduced separately and linked to the main model via the audio tracks. A goal of our model is to enhance the understanding of the cultural site also for partially sighted as well as sighted people, making them able to appreciate the details of the architectural design using both visual and auditory senses. We exploited low-cost and partially open-source technologies, thus rendering our system easily replicable. We evaluated the interactive system with blind, partially sighted, and sighted users. Our user test confirmed the validity of our approach: (1) the 3D models and the tactile reproduction of details obtained via a low-cost 3D printing solution are well perceived by touch; (2) the semantic auditory information activated via perceptible buttons on demand and the different content levels for the audio tracks are suitable for an interactive, autonomous, and satisfying exploration; and (3) relevant details are well perceived. Finally, we propose guidelines to use in the 3D reproduction of buildings or large sites based on our experience
Smart Cultural Site: An Interactive 3d Model Accessible to People with Visual Impairment
Full text linkIn our study, we proposed a prototype of "Piazza dei Miracoli" (Pisa, Italy) as an intelligent 3D interface system aimed at improving the accessibility and usability of cultural sites for all, including people with vision impairment. We combine tactile information with audio tracks in order to enable potential users to explore the artifact autonomously. Low-cost and partially open-source technologies are two important features leading our approach, creating a system easily replicable. First, we designed some 3D source-based models to be printed with an additive manufacturing technology. Next, the 3D prototype has been linked to a Raspberry for handling a set of detailed audio tracks to enrich the tactile exploration with an interactive audio guide. A preliminary evaluation was conducted to test the proposed system in order to better refine its design
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