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 position paper outlines the authors’ vision on how the Web of Things, using interconnected devices, including sensor nodes, mobile phones and conventional computers can help improve the overall health and wellbeing of its users. We describe ongoing work being carried by our research group both at PUC-Rio and at Lancaster University as well as the motivating background.

http://groupware.les.inf.puc-rio.br/public/papers/2011.Velloso.WebScience_FinalVersion.pdf

The Web of Things as an Infrastructure for Improving Users’ Health and Wellbeing

As our interactions increasingly cut across diverse devices, we often encounter situations where we find information on one device but wish to use it on another device, for instance, a phone number spotted on a public display but wanted on a mobile. We conceptualize this problem as Select & Apply and contribute two user studies where we presented participants with eight different scenarios involving different device combinations, applications and data types. In the first, we used a think-aloud methodology to gain insights on how users currently accomplish such tasks and how they ideally would like to accomplish them. In the second, we conducted a focus group study to investigate which factors influence their actions. Results indicate shortcomings in present support for Select & Apply and contribute a better understanding of which factors affect cross-device interaction.

/pdf/select-apply-understanding-how-users-act-upon-objects-across-i5k2zvvlmv.pdf

Select & apply: understanding how users act upon objects across devices

Our everyday life is surrounded by pervasive services. While on the run we should be able to use the mobile devices we carry to interact with these services. Yet, a number of studies have shown that it is difficult for users to identify available services in an unknown context. RelateGateways extends the desktop of a mobile device with a new kind of widget: the gateways, arranged around the edge of the screen, pointing towards the co-located services. Identified services can be consumed in a consistent manner by dragging-and-dropping an object on the gateway.

https://www.medien.ifi.lmu.de/pubdb/publications/pub/fischer2007ubidemo/fischer2007ubidemo.pdf

RelateGateways: Using Spatial Context to Identify and Interact with Pervasive Services

As an example of sensory augmentation of a tiny object, a small cube-sized die is presented that perceives rolls and records what face it lands on. It is thus able to detect bias for unfair behaviour due to its physical imperfections. On a deeper level, this case study demonstrates the integration of energy-efficient sensor fusion, combination of classifiers, and a wireless interface to adaptive classification heuristics.

/pdf/fair-dice-a-tilt-and-motion-aware-cube-with-a-conscience-2pywqnwfdc.pdf

Fair Dice: A Tilt and Motion-Aware Cube with a Conscience

Individuals, groups and organizations host places in the World Wide Web to attract visitors, but once they have established a web presence they usually maintain little or no awareness of visiting activity. However, the standard web infrastructure supports the capture of detailed activity-related information. In the first part of this paper, we contribute a preliminary study conducted with expert web hosts in different domains, investigating the use of information on visiting activity as feedback for web operation. From this study, we infer general requirements for web awareness support, based on which we have designed two systems aimed to promote more awareness of web activity and visitors. The first is a system supporting ambient notification of web events, end-user configurability, and ambient display for overview and comparison of activity in a web place. The second system moves beyond awareness of web activity to provide glances into the visitors’ sites, introducing reciprocity to the host–visitor relationship. Both systems have been prototyped and deployed in work environments for an evaluation in everyday use.

Hans Gellersen

Papers

The Web of Things as an Infrastructure for Improving Users’ Health and Wellbeing

Select & apply: understanding how users act upon objects across devices

RelateGateways: Using Spatial Context to Identify and Interact with Pervasive Services

Fair Dice: A Tilt and Motion-Aware Cube with a Conscience

Look Who's Visiting: Supporting Awareness for Visitors in the Web