There are many navigation systems for visually impaired people but few can provide dynamic interactions and adaptability to changes. None of these systems work seamlessly both indoors and outdoors. Drishti uses a precise position measurement system, a wireless connection, a wearable computer, and a vocal communication interface to guide blind users and help them travel in familiar and unfamiliar environments independently and safely. Outdoors, it uses DGPS as its location system to keep the user as close as possible to the central line of sidewalks of campus and downtown areas; it provides the user with an optimal route by means of its dynamic routing and rerouting ability. The user can switch the system from an outdoor to an indoor environment with a simple vocal command. An OEM ultrasound positioning system is used to provide precise indoor location measurements. Experiments show an in-door accuracy of 22 cm. The user can get vocal prompts to avoid possible obstacles and step-by-step walking guidance to move about in an indoor environment. This paper describes the Drishti system and focuses on the indoor navigation design and lessons learned in integrating the indoor with the outdoor system. 1.

The RERC Center on Aging at the University of Florida is dedicated to creating smart environments and assistants to enable elderly persons to live a longer and a more independent life at home. By achieving this goal, technology will increase the chances of successful aging despite an ailing Health Care system (e.g. Medicaid). One of the essential services required to maximize the intelligence of a smart environment is an indoor precision tracking system. Such system allows the smart home to make proactive decisions to better serve its occupants by enabling context-awareness instead of being solely reactive to their commands. This paper presents our hands-on experience and lessons learnt from our first phase work to build up a smart home infrastructure for the elderly. We review location tracking technology and describe the rational behind our choice of the emerging ultrasonic sensor technology. We give an overview of the House of Matilda (an in-laboratory mock up house) and describe our design of a precision in-door tracking system. We also describe an OSGi-based robust framework that abstracts the ultrasonic technology into a standard service to enable the creation of tracking based applications by third party, and to facilitate the collaboration among various devices and other OSGi services. Finally, we describe three pervasive computing applications that use the location-tracking system, which we have implemented in Matilda’s house.

The BATS project focuses on helping students with visual impairments access and explore spatial information using standard computer hardware and open source software. Our work is largely based on prior techniques used in presenting maps to the blind such as text-to-speech synthesis, auditory icons, and tactile feedback. We add spatial sound to position auditory icons and speech callouts in three dimensions, and use consumer-grade haptic feedback devices to provide additional map information through tactile vibrations and textures. Two prototypes have been developed for use in educational settings and have undergone minimal assessment. A system for public release and plans for more rigorous evaluation are in development.

Capturing, defining, and modeling the essence of context are challenging, compelling, and prominent issues for interdisciplinary research and discussion. The roots of its emergence lie in the inconsistencies and ambivalent definitions across and within different research specializations (e.g., philosophy, psychology, pragmatics, linguistics, computer science, and artificial intelligence). Within the area of computer science, the advent of mobile context-aware computing has stimulated broad and contrasting interpretations due to the shift from traditional static desktop computing to heterogeneous mobile environments. This transition poses many challenging, complex, and largely unanswered research issues relating to contextual interactions and usability. To address those issues, many researchers strongly encourage a multidisciplinary approach. The primary aim of this article is to review and unify theories of context within linguistics, computer science, and psychology. Summary models within each discipline are used to propose an outline and detailed multidisciplinary model of context involving (a) the HUMAN--COMPUTER INTERACTION, 2005, Volume 20, pp. 403--446 Copyright 2005, Lawrence Erlbaum Associates, Inc.

This is an author-produced version of a paper published in Personal and

Abstract–Wearable computers can certainly support audio-only presentation of information; a visual interface need not be present for effective user interaction. A System for Wearable Audio Navigation (SWAN) is being developed to serve as a navigation and orientation aid for persons temporarily or permanently visually impaired. SWAN is a wearable computer consisting of audio-only output and tactile input via a taskspecific handheld interface device. SWAN aids a user in safe pedestrian navigation and includes the ability for the user to author new GIS data relevant to their needs of wayfinding, obstacle avoidance, and situational awareness support. Emphasis is placed on representing pertinent data with nonspeech sounds through a process of sonification. SWAN relies on a Geographic Information System (GIS) infrastructure for supporting geocoding and spatialization of data. Furthermore, SWAN utilizes a novel tracking system. 1

We report on two route guidance tasks using a highly accurate GPS receiver. Eight participants who were visually impaired or blind traveled two routes, one on a city sidewalk, and one in a city park. We tested and compared two types of spatial output devices that give route guidance information. One output display used a hand-held pointer, using a standard Talking Signs receiver that integrated the GPS signal information with the Talking Signs ® signal information. This device gave travel instructions and oncourse confirmation when pointed in the proper direction. The other spatial display used auditory virtual reality that presented the audible spatial information (waypoint direction and distance) through small air-tubes inserted into the ear. Travel times, distance, and errors were recorded. In addition, we tested users ’ ability to find precise locations, such as the intersections of small paths and a bus stop pole. Various subjective ratings were collected about blind participants ’ needs and perception of the various display and output options that they used. All subjects completed the tasks with both output displays, found all the waypoints and locations, and rated the two displays highly. The virtual sound display produced superior times overall and received slightly higher favorable ratings.

Research into context-aware computing has not sufficiently addressed human and social aspects of design. Existing design frameworks are predominantly software orientated, make little use of cross-disciplinary work, and do not provide an easily transferable structure for cross-application of design principles. To address these problems, this paper proposes a multidisciplinary and user-centred design framework, and two models of context, which derive from conceptualisations within Psychology, Linguistics, and Computer Science. In a study, our framework was found to significantly improve the performance of postgraduate students at identifying the context of the user and application, and the usability issues that arise.

spatial representations derived from spatial language can function equivalently to those derived from perception. The authors tested functional equivalence for reporting spatial relations that were not explicitly stated during learning. Participants learned a spatial layout by visual perception or spatial language and then made allocentric direction and distance judgments. Experiments 1 and 2 indicated allocentric relations could be accurately reported in all modalities, but visually perceived layouts, tested with or without vision, produced faster and less variable directional responses than language. In Experiment 3, when participants were forced to create a spatial image during learning (by spatially updating during a backward translation), functional equivalence of spatial language and visual perception was demonstrated by patterns of latency, systematic error, and variability. People typically learn about space by means of direct perception. By viewing, hearing, touching, or moving around objects in their environment, they can form spatial representations of their physical surroundings. However, mental representations of space are not formed exclusively through direct perceptual input. They can also be constructed indirectly by means of symbolic media

Abstract — Trinetra aims to develop cost-effective assistive technologies to provide blind people with a greater degree of independence in their daily activities. The overall objective of the Trinetra system is to improve the quality of life for the blind by harnessing the collective capability of diverse networked embedded devices to support navigation, grocery shopping, transportation, etc. This paper describes our research and development of the original Trinetra prototype, a barcode-based solution comprising a combination of off-the-shelf components, such as an Internet- and Bluetooth-enabled cell phone, text-tospeech software and a portable barcode reader. We also describe our experiences with the first deployment and evaluation of Trinetra to aid grocery shopping for the blind at the Carnegie Mellon University’s campus convenience store, Entropy.