Runar Unnthorsson

Designing sensory-substitution devices: Principles, pitfalls and potential1

An exciting possibility for compensating for loss of sensory function is to augment deficient senses by conveying missing information through an intact sense. Here we present an overview of techniques that have been developed for sensory substitution (SS) for the blind, through both touch and audition, with special emphasis on the importance of training for the use of such devices, while highlighting potential pitfalls in their design. One example of a pitfall is how conveying extra information about the environment risks sensory overload. Related to this, the limits of attentional capacity make it important to focus on key information and avoid redundancies. Also, differences in processing characteristics and bandwidth between sensory systems severely constrain the information that can be conveyed. Furthermore, perception is a continuous process and does not involve a snapshot of the environment. Design of sensory substitution devices therefore requires assessment of the nature of spatiotemporal continuity for the different senses. Basic psychophysical and neuroscientific research into representations of the environment and the most effective ways of conveying information should lead to better design of sensory substitution systems. Sensory substitution devices should emphasize usability, and should not interfere with other inter- or intramodal perceptual function. Devices should be task-focused since in many cases it may be impractical to convey too many aspects of the environment. Evidence for multisensory integration in the representation of the environment suggests that researchers should not limit themselves to a single modality in their design. Finally, we recommend active training on devices, especially since it allows for externalization, where proximal sensory stimulation is attributed to a distinct exterior object.

Sound of Vision - Spatial Audio Output and Sonification Approaches

The paper summarizes a number of audio-related studies conducted by the Sound of Vision consortium, which focuses on the construction of a new prototype electronic travel aid for the blind. Different solutions for spatial audio were compared by testing sound localization accuracy in a number of setups, comparing plain stereo panning with generic and individual HRTFs, as well as testing different types of stereo headphones vs custom designed quadrophonic proximaural headphones. A number of proposed sonification approaches were tested by sighted and blind volunteers for accuracy and efficiency in representing simple virtual environments.

The Sound of Vision Project: On the Feasibility of an Audio-Haptic Representation of the Environment, for the Visually Impaired

The Sound of Vision project involves developing a sensory substitution device that is aimed at creating and conveying a rich auditory representation of the surrounding environment to the visually impaired. However, the feasibility of such an approach is strongly constrained by neural flexibility, possibilities of sensory substitution and adaptation to changed sensory input. We review evidence for such flexibility from various perspectives. We discuss neuroplasticity of the adult brain with an emphasis on functional changes in the visually impaired compared to sighted people. We discuss effects of adaptation on brain activity, in particular short-term and long-term effects of repeated exposure to particular stimuli. We then discuss evidence for sensory substitution such as Sound of Vision involves, while finally discussing evidence for adaptation to changes in the auditory environment. We conclude that sensory substitution enterprises such as Sound of Vision are quite feasible in light of the available evidence, which is encouraging regarding such projects.

Operation and Maintenance in Icelandic Geothermal Power Plants: Structure and Hierarchy

The Icelandic geothermal industry can be traced back to 1908 and has developed an extensive knowledge from that time. Currently, seven geothermal power plants are operating on the island. The plants are operated and maintained efficiently by relatively few engineers. The power plants generally prefer marine engineers who have worked as chief engineers on fishing vessels. Marine engineers are preferred in the Icelandic geothermal sector because of their education and mentality learned while working on the sea. Teamwork, resourcefulness, proactive thinking and the will to assist with jobs beyond job description are among the qualities believed to be required.This study was carried out in cooperation with three power companies who own and operate all the geothermal power plants in Iceland. The purpose was to study the geothermal power plants and their environment in order to identify the key factors for the effective operation and maintenance with few engineers. The results include a summary and an analysis of the structure and hierarchy and an analysis of the business environment. Lastly, the results from a comparison of work behavior between employees at geothermal plants, fishing vessels and from other sectors are presented. Results were not as expected; employees at the geothermal plant were less considered to their peers, more outspoken and seem to show less civic virtue to their companies.Copyright

Methane yield enhancement via electroporation of organic waste

An experimental study with pulsed electric field (PEF) pre-treatment was conducted to investigate its effect on methane production. PEF pre-treatment converts organic solids into soluble and colloidal forms, increasing bioavailability for anaerobic microorganisms participating in methane generation process. The substrates tested were landfill leachate and fruit/vegetable. Three treatment intensities of 15, 30, and 50kWh/m3 were applied to investigate the influence of pre-treatment on methane production via biochemical methane potential test. Threshold treatment intensity was found to be around 30kWh/m3 for landfill leachate beyond which the methane production enhanced linearly with increase in intensity. Methane production of the landfill leachate significantly increased up to 44% with the highest intensity. The result of pulsed electric field pre-treatment on fruit/vegetable showed that 15kWh/m3 was the intensity by which the highest amount of methane (up to 7%) was achieved. Beyond this intensity, the methane production decreased. Chemical oxygen demand removals were increased up to 100% for landfill leachate and 17% for fruit/vegetable, compared to the untreated slurries. Results indicate that the treatment intensity has a significant effect on the methane production and biosolid removal.

Current Use and Future Perspectives of Spatial Audio Technologies in Electronic Travel Aids

Electronic travel aids (ETAs) have been in focus since technology allowed designing relatively small, light, and mobile devices for assisting the visually impaired. Since visually impaired persons rely on spatial audio cues as their primary sense of orientation, providing an accurate virtual auditory representation of the environment is essential. This paper gives an overview of the current state of spatial audio technologies that can be incorporated in ETAs, with a focus on user requirements. Most currently available ETAs either fail to address user requirements or underestimate the potential of spatial sound itself, which may explain, among other reasons, why no single ETA has gained a widespread acceptance in the blind community. We believe there is ample space for applying the technologies presented in this paper, with the aim of progressively bridging the gap between accessibility and accuracy of spatial audio in ETAs.

Different Approaches to Aiding Blind Persons in Mobility and Navigation in the “Naviton” and “Sound of Vision” Projects

In this chapter, we summarize several years of research efforts aimed at building ICT (Information and Communications Technologies) based systems for aiding the blind in travel and navigation at the Lodz University of Technology, mainly as part of the “Naviton” project (http://www.naviton.pl), from a Polish Ministry of Higher Education grant. We report on different approaches we undertook in these challenging goals which comprise the following prototype solutions: (1) sonified stereovision system for obstacle avoidance and environment imaging, (2) radio beacons for local navigation, (3) remote assistance system, (4) mobile navigation applications, (5) real-time tracking of public transport vehicles, (6) haptic imaging . We shortly describe these technologies and discuss user feedback from the trials of these technological aids. Finally, we point out the key objectives and first results of a Horizon 2020 project entitled “Sound of Vision: natural sense of vision through acoustics and haptics” (http://www.soundofvision.net) that started in 2015.

Blind wayfinding with physically-based liquid sounds

Abstract Translating visual representations of real environments into auditory feedback is one of the key challenges in the design of an electronic travel aid for visually impaired persons. Although the solutions currently available in the literature can lead to effective sensory substitution, high commitment to an extensive training program involving repetitive sonic patterns is typically required, undermining their use in everyday life. The current study explores a novel sensory substitution algorithm that extracts information from raw depth maps and continuously converts it into parameters of a naturally sounding, physically based liquid sound model describing a population of bubbles. This approach is tested in a simplified wayfinding experiment with 14 blindfolded sighted participants and compared against the most popular sensory substitution algorithm available in the literature – the vOICe (Meijer, 1992) – following a short-time training program. The results indicate a superior performance of the proposed sensory substitution algorithm in terms of navigation accuracy, intuitiveness and pleasantness of the delivered sounds compared to the vOICe algorithm. These results should be applied to the visually impaired population with caution.

Auditory depth map representations with a sensory substitution scheme based on synthetic fluid sounds

A novel sensory substitution algorithm based on the sonification of depth maps into physically based fluid flow sounds is described. Spatial properties are extracted from depth maps and mapped into parameters of an empirical phenomenological model of bubble statistics, which manages the generation of the corresponding synthetic fluid flow sound. Following minimal training, the proposed approach was tested in a preliminary experiment with 20 normally sighted participants and compared against the well-known vOICe sensory substitution algorithm. Although the accuracy in recognizing visual sequences based on the corresponding sonification is comparable between the two systems, an overwhelming support for the fluid sounds compared to the vOICe output in terms of pleasantness was recorded. Collected data further suggests that ample margins of performance improvement are achievable following thorough training procedures.

Wellhead Scaling Problems in Geothermal Power Plants Addressed Using a Needle Valve Derivative

One of the most frequent problems in geothermal power plants is scaling. If scaling is allowed to build in the wellhead it can hinder the flow from the well. In this study we investigate how exactly that problem was solved at HS Energy in Iceland. We look at the problem, describe it and how it has been successfully solved. The solution, a valve called the Elli valve, which can be regarded a derivative of the Giffard’s injector, is then described. This valve has been shown to allow for a better flow control, less problems with regards to scaling removal and has economical advantages over other control valves. This solution should allow geothermal power plants dealing with scaling problems to use the presented solution to solve it effectively, in a cost efficient manner.Copyright