Henk L. Muller

Ambient wood: designing new forms of digital augmentation for learning outdoors

Ubiquitous and mobile technologies provide opportunities for designing novel learning experiences that move out of the classroom. Information can be presented and interacted with in a variety of ways while exploring a physical environment. A key issue this raises is when, where, what and how much? Our research is concerned with the design, delivery and interaction of digital information when learning about ecology outdoors. We present a framework of the different forms of digital augmentation and the different processes by which they can be accessed. Using the framework, we designed an outdoors learning experience, aimed at encouraging students to carry out contextualized scientific enquiry and to reflect on their interactions. Pairs of 11-12 year olds explored a woodland and were presented at certain times with different forms of digital augmentation. Our study showed that this kind of exploration promoted interpretation and reflection at a number of levels of abstraction.

Context awareness by analysing accelerometer data

In this paper we describe continuing work being carried out as part of the Bristol Wearable Computing Initiative. We are researching processing techniques for data from accelerometers which enable the wearable computer to determine the users activity. Techniques already employed by others have been explored and we propose new methods for analysing the data delivered by these devices. We try to minimise the number of devices needed by using a single X-Y accelerometer device. Using our techniques we have adapted our GPS based Tourist Guide application to vary its multimedia presentation according to the users activity as well as location.

Shakra: tracking and sharing daily activity levels with unaugmented mobile phones

This paper explores the potential for use of an unaugmented commodity technology—the mobile phone—as a health promotion tool. We describe a prototype application that tracks the daily exercise activities of people, using an Artificial Neural Network (ANN) to analyse GSM cell signal strength and visibility to estimate a user’s movement. In a short-term study of the prototype that shared activity information amongst groups of friends, we found that awareness encouraged reflection on, and increased motivation for, daily activity. The study raised concerns regarding the reliability of ANN-facilitated activity detection in the ‘real world’. We describe some of the details of the pilot study and introduce a promising new approach to activity detection that has been developed in response to some of the issues raised by the pilot study, involving Hidden Markov Models (HMM), task modelling and unsupervised calibration. We conclude with our intended plans to develop the system further in order to carry out a longer-term clinical trial.

Low Cost Indoor Positioning System

This report describes a low cost indoor position sensing system utilising a combination of radio frequency and ultrasonics. Using a single rf transmitter and four ceiling mounted ultrasonic transmitters it provides coverage in a typical room in an area greater than 8m by 8m. As well as finding position within a room, it uses data encoded into the rf signal to determine the relevant web server for a building, and which floor and room the user is in. It is intended to be used primarily by wearable/mobile computers, though it has also been extended for use as a tracking system.

Personal position measurement using dead reckoning

This paper compares position measurement techniquesusing dead reckoning. We are seeking to find a techniquewhich is suitable for use by pedestrians, and have compareda number of sensors that can be used to achieve a robustand accurate dead reckoning system. All our techniquesare step based. To measure steps we have compared the useof pedometers and accelerometers. To determine headingwe have compared two and three dimensional compassesand a rate gyroscope. Finally we have performed four casestudies based on real applications with standard deviationmeasured at 2.2m for a short test and 19.9m for an extendedtest. These errors can be reduced by using more computationallyexpensive filtering operations.

Random Register Renaming to Foil DPA

Techniques such as DPA and SPA can be used to find the secret keys stored in smart-cards. These techniques have caused concern for they can allow people to recharge their stored value smartcards (in effect printing money), or illegally use phone or digital TV services. We propose an addition to current processors which will counteract these techniques. By randomising register usage, we can hide the secret key stored in a smartcard. The extension we propose can be added to existing processors, and is transparent to the algorithm.

Increasing the Awareness of Daily Activity Levels with Pervasive Computing

Public health promotion technology should be accessible to the general public at which it is aimed. This paper explores the potential for use of an unaugmented commodity technology - the mobile phone - as a health promotion tool. We describe a prototype application that tracks the daily exercise activities of people carrying phones, using fluctuation in signal strength to estimate a users movement. In a short-term study of the prototype that shared activity information amongst groups of friends, we found that awareness encouraged reflection on, and increased motivation for, daily activity. We describe some of the details of the pilot study, and conclude with our intended plans to develop the system further in order to carry out a longer-term clinical trial

Non-deterministic Processors

New techniques have been discovered to find the secret keys stored in smart-cards. These techniques have caused concern for they can allow people to recharge their smartcards (in effect printing money), or illegally use phone or digital TV services. We propose a new processor design which will counteract these techniques. By randomising the instruction stream being executed by the processor we can hide the secret key stored in a smartcard. The extension we propose can be added to existing processors, and is transparent to the algorithm.

Things aren't what they seem to be: innovation through technology inspiration

How does designing for novel experiences with largely untried technologies get its inspiration? Here we report on a project whose goal was to promote learning through novel, playful visions of technologies. To this end, we experimented with a diversity of ambient and pervasive technologies to inspire and drive our design. Working as a large multi-disciplinary group of researchers and designers we developed novel and imaginative experiences for children. To crystallise our ideas we designed, implemented and experimented with a mixed reality adventure game, where children had to hunt an elusive, virtual creature called the Snark, in a large interactive environment. We describe our experiences, reflecting on the process of design inspiration in an area where so much remains unknown.

RF free ultrasonic positioning

All wearable centric location sensing technologies mustaddress the issue of clock synchronisation between signaltransmitting systems and signal receiving systems. GPS receivers,for example, compensate for synchronisation errorsby incorporating a model of the receiver clock offsetin the navigation solution. Drift between satellite clocks isalso monitored to keep signal data in synch with GPS time.Most ultrasonic positioning systems solve the synchronisationproblem by using a second medium for communicationbetween transmitter and receiver devices. The transmittersin these systems emit RF signals (pings) to indicatethe transmission of subsequent ultrasound signals (chirps).By subtracting the arrival time of the ping from that of thechirps, the receiver is able to compute the distance to eachtransmitter.In this paper, we describe an ultrasonic positioning systemthat does not use RF signals to achieve synchronisation.Instead, it exploits a periodic chirp transmission pattern tomodel the receivers position using chirp reception timesexclusively. Not only does the system improve on the accuracyof previous technologies but it also eliminates bulky RFcircuitry - a definite advantage for wearable applicationswhere component size and weight are critical for usability.