University of Helsinki Department of Computer Science

Department of Computer Science

Department information


Context Recognition by User Situation Data Analysis (Context)

The Context project has released the ContextPhone mobile context-aware prototyping platform as free software.


Project overview

In mobile and ubiquitous applications and systems, reacting to user context is a key component of proactivity: changes in the user's situation are rapid and they are strongly reflected to the user's needs and preferences. The Context project studies characterization and analysis of information about user's context and its use in proactive adaptivity: what is the user's understanding of her current context, how to make automatic inferences about the contexts, and how to characterize context to users and design user interaction about contexts. The research problems are approached by qualitative end user studies, data analysis algorithm development, and empirical testing in a prototype environment.

The project is a joint effort of the Department of Computer Science and HIIT Basic Research Unit, both at University of Helsinki, and of HIIT Advanced Research Unit. The research project is funded by the Academy of Finland during years 2002-2005.

Researchers at University of Helsinki/HIIT BRU, the Discovery Group: Prof. Hannu Toivonen, Kari Laasonen, Juho Muhonen, Renaud Petit, and Mika Raento

Researchers at HIIT/ARU: Prof. Martti Mäntylä, Antti Oulasvirta, Matti Rantanen, and Sauli Tiitta. (Project www page at HIIT/ARU)

Evolution of ContextPhone after the Context project

Since 2006, Jaiku Ltd. has developed commercial mobile presence services based on ContextPhone technology and application prototypes (see below).

Since October 2007, Jaiku is part of Google.


Smartphones are the first real pervasive platform. They are always with you and have the processing power and network connectivity of a 1995 PC. A service or application that works on a Smartphone has the unique capability of being available throughout your everyday life.

To make building real applications easier, we have released ContextPhone. ContextPhone consists of four interconnected main modules (see System diagram) provided as a set of open source C++ libraries and source code components, running on off-the-shelf mobile phones (using Symbian OS and the Series 60 Smartphone platform):

are used to acquire context data from different sources, such as location (cell identifier and GPS) or phone usage.
provide connections to services in the outside world via standard Internet protocols using GPRS, Bluetooth transfers, short messages (SMS) and multimedia messages (MMS). The communication channels can be used, e.g., to share presence information (Jabber) or to obtain sensor data (GPS over Bluetooth).
versions of built-in applications} are provided, in particular for the Contacts and Recent call list, to seamlessly replace the original ones.
System services
provide facilities for automatic starting of background services, error logging and recovery as well as status display.

Obtaining ContextPhone

ContextPhone is available under the GNU General Public License (GPL): it is free software that can be redistributed or modified as long as the modified versions are made available under the same terms.

The software works on Nokia Series 60 version 1 and 2 Smartphones, running Symbian OS 6.0 and 7.0s (e.g. Nokia 7650, 3650, 6600 and 7610, Now with experimental support for FP2: 6630). Binaries, source code (approximately 50 KLOC at the time of writing), installation notes and a building guide can be found at

A version of ContextMedia has now been made available for general use. It uses flickr as the media platform (but can easily be adapted to other services). Get it from

Example applications


ContextContacts is a service for automatic communication and representation of the context of your buddies. Recent research has shown that (depending on the sample) 30-70% of all mobile calls fail. This causes undue stress to people and of course the lost time costs money in business. By giving contextual cues about the callees current situation we aim to reduce the number of failed communication attempts:

ContextContacts is also an important vehicle for studying how such automatic publication of ones context can be integrated into the way people manage privacy: what data can safely be communicated, how should the service be controlled and what level of accountability should be provided (amongst others).


A version of ContextMedia has now been made available for general use. It uses flickr as the media platform (but can easily be adapted to other services). Get it from

Smartphones enable not only the capture of media, but also the annotation and sharing of this media. With ContextMedia you can immediately store or share media (photos, sound, video, text) you capture on your Smartphone:

Results can be seen on the aware spatio-temporal moblog.


ContextLogger is an application for recording mobility data. The goal has been to provide a tool for researchers to acquire rich data in a manner that is unobtrusive to the user, requires minimum control and maintenance, and is robust and reliable. Example log. Of course this data can be used by the users themselves to keep an automated diary.

The ability to measure the evolution and strength of social relationships can ``revolutionise the field of social network analysis'' according to the social scientist David Lazer of Harvard University (Celeste Biever. The phone that knows you better than you do. New Scientist, 184:22, 2004.)

Users of ContextPhone


ContextPhone in the press

Press release:

ContextPhone has also been covered in China, Germany, Hungary, India, Italy, Russia, and UK.


We have gathered a dataset on mobile context and communication. An anonymized version is publicly available. If you need access to features not in that version, please contact Mika Raento.

At the moment we might still modify the dataset slightly. If you plan to use it, please contact us so that we can verify you get a correct version and that we freeze that version for future reference.



There's a LaTeX slides template available for making presentations.

We've put up some notes about our experiences with Symbian programming

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