UDAE: Universal Data Access Engine for Sensor Networks

We present the design and implementation of UDAE, a universal data access engine for wireless sensor networks. The UDAE allows developers to access data both locally and over the network from a variety of sources, such as sensors, communications links and platform components in a unified manner. It is also fully extensible, allowing data sources and users to be added flexibly at run-time. This enables capabilities for cross-component optimization and run-time configuration. In order to validate our proposed system, we have implemented UDAE for two operating systems (Contiki and TinyOS). While the TinyOS implementation has been done as native code, the Contiki implementation is based on a reconfigurable component-oriented middleware enabling developers to fully benefit from the flexibility offered by the UDAE. Both of these implementations have been made publicly available under an open source license. A detailed performance evaluation carried out with these implementations shows that the overhead induced by the adoption of UDAE in terms of memory, processing requirements and energy consumption is very small and the additional latencies induced by the framework negligible. We also discuss various different application scenarios for UDAE in some detail, particularly cross-component optimization and run-time configuration. Furthermore, a practical case study of cross-component optimization selected from the TinyOS domain is addressed.