Tactile Working Memory Capacity of Users Who Are Blind in an Electronic Travel Aid Application with a Vibration Belt

Electronic travel aids (ETAs) can increase the safety and comfort of pedestrians who have a visual impairment by displaying obstacles through a vibrotactile navigation belt. Building a complete picture of relevant obstacles and finding a safe route requires ETA users to integrate vibrotactile cues over time and space in their tactile working memory. Previous research suggests that the sense of touch exhibits a working memory that has characteristics similar to vision and audition. However, the capacity of the tactile working memory and the effects of secondary tasks are still under-researched. We investigated tactile working memory capacity of 14 adolescent participants who are blind in an immediate, whole report recall test. Participants received trials consisting of one to five vibration patterns presented sequentially at different locations on their torso representing obstacles with a direction (vibration location) and distance (vibration pattern). Recall performance was assessed under four conditions: baseline and with distracting background sounds and/or while walking with the long cane. Both walking and ignoring distracting sounds are relevant for everyday use of an ETA and were expected to decrease memory performance. We calculated the 75% correct scores for two memory performance measures: the number of items in a trial (numerosity), and item location and pattern correct. In the baseline condition, the scores were close to ceiling (i.e., 5 items). However, in the presence of distracting sounds and while walking, the scores were reduced to 3.2 items for numerosity and 1.6 items for location and identity correct. We recommend using 2 items as the maximum tactile working memory load in an applied setting unless users are trained and/or can adopt their strategy without unacceptable costs, such as reducing their walking speed

Enhancing human understanding through intelligent explanations,”

Abstract. Ambient systems that explain their actions promote the user's understanding as they give the user more insight in the effects of their behavior on the environment. In order to provide individualized intelligent explanations, we need not only to evaluate a user's observable behavior, but we also need to make sense of the underlying beliefs, intentions and strategies. In this paper we argue for the need of intelligent explanations, identify the requirements of such explanations, propose a method to achieve generation of intelligent explanations, and report on a prototype in the training of naval situation assessment and decision making. We discuss the implications of intelligent explanations in training and set the agenda for future research

Obstacle detection display for visually impaired:Coding of direction, distance, and height on a vibrotactile waist band

Electronic travel aids (ETAs) can potentially increase the safety and comfort of blind users by detecting and displaying obstacles outside the range of the white cane. In a series of experiments, we aim to balance the amount of information displayed and the comprehensibility of the information taking into account the risk of information overload. In Experiment 1, we investigate perception of compound signals displayed on a tactile vest while walking. The results confirm that the threat of information overload is clear and present. Tactile coding parameters that are sufficiently discriminable in isolation may not be so in compound signals and while walking and using the white cane. Horizontal tactor location is a strong coding parameter, and temporal pattern is the preferred secondary coding parameter. Vertical location is also possible as coding parameter but it requires additional tactors and makes the display hardware more complex and expensive and less user friendly. In Experiment 2, we investigate how we can off-load the tactile modality by mitigating part of the information to an auditory display. Off-loading the tactile modality through auditory presentation is possible, but this off-loading is limited and may result in a new threat of auditory overload. In addition, taxing the auditory channel may in turn interfere with other auditory cues from the environment. In Experiment 3, we off-load the tactile sense by reducing the amount of displayed information using several filter rules. The resulting design was evaluated in Experiment 4 with visually impaired users. Although they acknowledge the potential of the display, the added of the ETA as a whole also depends on its sensor and object recognition capabilities. We recommend to use not more than two coding parameters in a tactile compound message and apply filter rules to reduce the amount of obstacles to be displayed in an obstacle avoidance ETA.</p

Values in Design Methodologies for AI

Addressing and integrating human values into AI design and development processes in research and practice can be di cult, and a clear methodological approach can clarify issues of both theory and prac- tice. One such approach is Value Sensitive Design (VSD), an established theory for addressing issues of values in a systematic and principled fash- ion in the design of information technology. However, it is unclear how VSD is translated into current design practices and whether it has been integrated into existing methodologies. In this paper, we investigated whether and to what extent VSD has passed down into design method- ologies used in practice. We found that the actual application of VSD in methodologies is limited, but that in the last few years, steps have been taken to bridge the gap between theory and practice

Blind user requirements to support tactile mobility

Various innovations have been identified in assistive technology for the visually impaired. One of these innovations are systems that present feedback and information in a tactile format. These tactile systems have the potential to help the visually impaired, but there is little attention to how it can be combined with other assistive technology. In this research, we present a set of user requirements for tactile systems, focusing on the needs of the visually impaired. This is done by telephone, personal, and group interviews. As a result, we identify three themes related to the use of non-visual tactile assistive devices for blind persons: 1) context of use, 2) trust issues, and 3) user interaction. Our recommendations include focusing on a devices that solve very specific mobility problems, being transparent with users about system status such as battery life and accuracy, and limiting output to prevent overload