There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

In this work, algorithms are developed and evaluated to de- tect physical activities from data acquired using five small biaxial ac- celerometers worn simultaneously on different parts of the body. Ac- celeration data was collected from 20 subjects without researcher su- pervision or observation. Subjects were asked to perform a sequence of everyday tasks but not told specifically where or how to do them. Mean, energy, frequency-domain entropy, and correlation of acceleration data was calculated and several classifiers using these features were tested. De- cision tree classifiers showed the best performance recognizing everyday activities with an overall accuracy rate of 84%. The results show that although some activities are recognized well with subject-independent training data, others appear to require subject-specific training data. The results suggest that multiple accelerometers aid in recognition because conjunctions in acceleration feature values can effectively discriminate many activities. With just two biaxial accelerometers - thigh and wrist - the recognition performance dropped only slightly. This is the first work to investigate performance of recognition algorithms with multiple, wire-free accelerometers on 20 activities using datasets annotated by the subjects themselves.

/pdf/activity-recognition-from-user-annotated-acceleration-data-lh3b5ajkau.pdf

Activity recognition from user-annotated acceleration data

How we Think

The theory of affordances

Cultivating Communities of Practice: A Guide to Managing Knowledge

This work investigated in Alzheimer's disease dementia (AD), whether the probability of making an error on a task (or a correct response) was influenced by the outcome of the previous trials. We used the antisaccade task (AST) as a model task given the emerging consensus that it provides a promising sensitive and early biological test of cognitive impairment in AD. It can be employed equally well in healthy young and old adults, and in clinical populations. This study examined eye-movements in a sample of 202 participants (42 with dementia due to AD; 65 with mild cognitive impairment (MCI); 95 control participants). The findings revealed an overall increase in the frequency of AST errors in AD and MCI compared to the control group, as predicted. The errors on the current trial increased in proportion to the number of consecutive errors on the previous trials. Interestingly, the probability of errors was reduced on the trials that followed a previously corrected error, compared to the trials where the error remained uncorrected, revealing a level of adaptive control in participants with MCI or AD dementia. There was an earlier peak in the AST distribution of the saccadic reaction times for the inhibitory errors in comparison to the correct saccades. These findings revealed that the inhibitory errors of the past have a negative effect on the future performance of healthy adults as well as people with a neurodegenerative cognitive impairment.

/pdf/the-effects-of-previous-error-and-success-in-alzheimer-s-1wowjx9ttx.pdf

The Effects of Previous Error and Success in Alzheimer’s Disease and Mild Cognitive Impairment

Much of the past pervasive computing research has been devoted to systems composed of a small number of devices that interact with a single individual or a small group of users. Body-worn sensors and sensors embedded in the user's environment were used to infer user location, activity, and information about the user's immediate surroundings, shaping the concept of context awareness. This issue is motivated by the fact that as technology becomes truly pervasive, we must proceed from the "single user, single system" perspective to "large-scale heterogeneous systems" involving many devices and many individuals collaborating over different spatial and temporal scales.

Beyond Context Awareness

Prior work has shown gaze behaviour correlates with mouse movement in conventional desktop interfaces. As many devices now employ direct touch instead of a mouse, we have conducted a first study analysing how gaze correlates with touch input. We collected touch and gaze data on a tablet from 24 participants, on search, shopping, and “link-following” tasks representative of typical online use of tablets. Our analysis shows a gaze fixation typically leads touch input by 337 ms within 197 pixels. We observed a stronger correlation in the context of link-following, in comparison with touch on other HTML objects and virtual keyboard.

/pdf/touch-input-and-gaze-correlation-on-tablets-17ck0qb263.pdf

Touch Input and Gaze Correlation on Tablets

By adding sensing capabilities to ear-worn devices, earables have emerged as a new platform. The ears are located closely to a number of important anatomical structures (e.g., brain, blood vessels). Also, the ear canal deforms upon facial movements and the ears can be comfortably touched by the hands. In a recent paper, we conducted a systematic literature review of 271 earable papers. We synthesized an open-ended taxonomy of 47 phenomena that can be sensed in, on, or around the ear. We identified 13 fundamental phenomena from which all other phenomena can be derived, and discuss sensing principles to detect them. The phenomena were reviewed in-depth in four main areas: (i) physiological monitoring and health, (ii) movement and activity, (iii) interaction, and (iv) authentication and identification. This breadth highlights the potential earables have to offer as a ubiquitous, general-purpose platform.

Excerpt from “Sensing with Earables: A Systematic Literature Review and Taxonomy of Phenomena”

The mostly used application is still telephony between two parties. Here the called party and the environment of the called party is usually interrupted by an incoming call. The social acceptability of phone usage evolves over time and differs according to the group of users, types of people, and also to the country. One common understanding that is shared over most of the users is that the one who uses the mobile phone is responsible to set the phone in a mode that is appropriate for the situation he or she is in. In most cases this is a binary decision switch the phone offor leave it on! This puts the trade-off:

Hans Gellersen

Papers

The Effects of Previous Error and Success in Alzheimer’s Disease and Mild Cognitive Impairment

Beyond Context Awareness

Touch Input and Gaze Correlation on Tablets

Excerpt from “Sensing with Earables: A Systematic Literature Review and Taxonomy of Phenomena”

Context-aware mobile telephony