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

The classic obstacles in the digital augmentation of everyday objects and appliances are usually situated around batteries, communication, size, and weight. Wired communication is often not possible, changing or charging batteries is generally considered a nuisance, and augmenting an appliance is usually not worth it if it means increasing its size or weight. For the subclass of devices and objects that are typically attached to surfaces such as walls and boards, we consider surface augmentation to address this problem. We present several implementations where low-cost wallpaper, consisting of insulated conductive layers, provides both power and a networking bus to common devices like pins on a notice board, wall switches, lights, and thermostats. They can be placed and replaced at will in any orientation, while the attachment to the wall supplies power and networking as a bonus. Moreover, our prototypes show that this doesn't affect familiarity of the objects, which makes interaction with them a breeze.

/pdf/pin-play-bringing-power-and-networking-to-wall-mounted-4hkgcz9lnt.pdf

Pin&Play: bringing power and networking to wall-mounted appliances

VoodooIO is a new architecture for physical user interfaces, providing interface devices that can be flexibly arranged on an interactive substrate. The architecture supports rapid assembly of physical interfaces and dynamic rearrangement of devices. In this paper we provide an account of a case study in which VoodooIO was used to rapidly build and explore a physical interface to an existing application, Google Earth. The case study gives insight into VoodooIO’s support for rapid prototyping of physical user interface applications.

The Friday Afternoon Project: A Two-Hour VoodooIO Prototyping Exercise.

We introduce Touch-Display Keyboards (TDK) that retain the traditional physical key layout and in addition provide dynamic display and touch-sensing capability for each key. We demonstrate how TDKs can be seamlessly integrated with graphical user interfaces by extending the graphical output as well as three-state input across the keyboard’s surface. TDKs allow the graphical interface to be dynamically distributed across keyboard and display, exploiting both the benefits of physical controls and the flexibility of graphical widgets.

/pdf/touch-display-keyboards-and-their-integration-with-graphical-1o68bqntm3.pdf

Touch-Display Keyboards and their Integration with Graphical User Interfaces

We propose a position detection mechanism enabling location-aware Pin&Play. Though the positions of inserted pins are important for most applications, it could not be detected in previous systems. The proposed method detects the positions of pins by processing images taken with a camera placed in front of the board. The proposed method has an error estimation mechanism to avoid the accumulation of position error. We also clarify the effectiveness of our proposed method through performance evaluations.

A Position Detection Mechanism enabling Location-aware Pin&Play

In this paper, we present an exploration of players’ nonverbal body expressions when playing survival-horror games. We compared physiological signals and body expressions of 16 participants playing two games: a survival-horror game (Slender: The Eight Pages) and a custom-built baseline game with the same map and controls (Treasure Hunt). We show that the hard fun style of Survival-Horror games makes full body expressions an unsuitable modality for affect recognition, but scary game events are clearly expressed by their physiological signals.

Hans Gellersen

Papers

Pin&Play: bringing power and networking to wall-mounted appliances

The Friday Afternoon Project: A Two-Hour VoodooIO Prototyping Exercise.

Touch-Display Keyboards and their Integration with Graphical User Interfaces

A Position Detection Mechanism enabling Location-aware Pin&Play

The body language of fear:fearful nonverbal signals in survival-horror games