A Wireless Sensor Network testbed for Information Fusion


Also see WSN Summer Project 2008

Project Overview

Wireless Sensor Networks (WSNs) play an increasingly more important role in surveillance and situation awareness systems. WSNs monitor parts of the environment, and need to provide timely alarms for any anomalies detected.  The Common Goals and Infrastructure project within the Information Fusion (IF) research program at University of Skövde, Sweden, aims at finding generic properties of infrastructures to be used for IF. Many IF applications rely on getting timely updates about the environment, with information used for time critical decisions. Typically infrastructures need to provide real-time guarantees, while distributing only the useful information, in a very large distributed system of more of less autonomous nodes.

To enable experiments with new IF algorithms and approaches, we are building up a WSN testbed for our IF lab. In collaboration with our industrial partners we will evaluate new IF based approaches for their business areas. This includes military vehicle recognition sensors (Exensor), surveillance situation awareness (SAAB), and soil monitoring for real-time precision agriculture (SLU/Agroväst).

Project Purpose

New testbed and lab resources allows integration of commercially available WSN and IF equipment, with specific sensors, equipment and algorithms used by our partners. The major goal is to be able to present how typical components and approaches need to be used and combined, to meet the complex requirements from typical IF applications.

Motivation

We have proposed an approach for a WSN/IF infrastructure based on commercially available hardware, including sensor nodes such as Crossbow’s Telos and MICAz motes, and more powerful mobile nodes, such as the Nokia N800/N810 tablet PC. Both type of units are small and mobile, and have an operating time of about a week. These development platforms are publicly available and can be easily extended for specific purposes. We use a multi-tiered approach to achieve scalability: The limited processing and storage resources of the sensor nodes are complemented by the more powerful tablet PCs[Mat07, Mat08]. In this architecture, sensors perform simple monitoring of the environment, and more processing-intensive computation is done at the upper tier. We will further extend this approach to allow more tiers, to process or fuse higher level information at further upper tiers.

We will specifically evaluate a database approach to large scale communication in IF infrastructures. Using a database for communication allows any node to safely publish and read information by using transactions, and the data becomes available in the database for all users of the a communication infrastructure. A distributed real-time database with eventual consistency and virtual full replication allows large scale systems to be built. In such systems users access their data locally as if the database was entirely locally available, while using a fraction of the resources in communication storage and processing required from a centralized communication approach. There is no need for unpredictable remote operations during database transactions since the database approach can replicate database objects to all nodes where they are available, resulting in that all transactions use only local data replicas.

Distributed Information Fusion allows fusion at lower levels, reducing the amount of data to propagate in the network, and also dissemination to users without passing a central node. Local decisions may be done based on lower levels of fused data, possibly more relevant to the local situation to control.

Problem

It is a complex problem to propagate updates timely through a resource-constrained network, and to provide the right abstraction level for information at points of decision. Further, implicit addressing of dynamic communication links is a complex issue for the users of a distributed solution.

It is difficult to understand generic requirements on an information fusion infrastructure, which information fusion methods are generally useful and how to apply them, without experiments and evaluations where requirements from different application scenarios are used. Deepening the collaboration with different such scenarios allows a deeper understanding from joint development of ideas and approaches.

Partners and collaborations

The project is currently supported by Saab Microwave Systems, Exensor, SLU/Agroväst. These companies already support the Information Fusion Program as external sponsors, but also want to deepen the collaboration regarding infrastructure issues, and also for future additional applications for research projects.

We also collaborate with University of Latvia with a group that specialize in sensor integration and software/hardware development for sensor platforms. Further, we have collaboration with the WSN group at University of Virginia. This group is one of the top three groups in the US for state-of-the art research in WSNs.

Current funding

The project is a part of the Information Fusion research profile, a research program at the University of Skövde within the area of information fusion from databases, sensors and simulations (http://www.infofusion.se), sponsored by a number of partners (http://www.his.se/infofusion/partners).

The Wireless Sensor Network testbed project has so far received direct funding for purchase of testbed equipment, such as 50 sensors and 4 tablet PCs. Additional funding is approved for project man-hours, for deepened collaboration with the partners in the three areas of military vehicle recognition, surveillance situation awareness, and soil monitoring.

Current equipment

References

[Mat07]  G. Mathiason, S.F. Andler, S.H. Son and L. Selavo (2007) Virtual Full Replication for Wireless Sensor Networks, Proceedings of the 19th ECRTS (WiP), Pisa, Italy, July 4-6 (http://feanor.sssup.it/ecrts07/)

[Mat08]  G. Mathiason, S.F. Andler, and S.H. Son (2008).  "Virtual Full Replication for Scalable and Adaptive Real-Time Communication in Wireless Sensor Networks", Proceedings of the Second International Conference on Sensor Technologies and Applications (SENSORCOMM 2008), Aug 25-31, Cap Esterel, France (http://www.iaria.org/conferences2008/SENSORCOMM08.html)

[Mat08b] G. Mathiason, S.F. Andler, and W. Kang (2008) "Exploring a Multi-Tiered Whiteboard Infrastructure for Information Fusion in Wireless Sensor Networks", Skövde Workshop on Information Fusion Topics (SWIFT 2008)


Uppdaterad: 2010-03-11
Sidansvarig: DRTS-gruppen